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[ { "abstract": "Gold based subwavelength photonic crystal (PhC) structures on GaAs substrate have been fabricated on a wafer scale. The structures have then been characterized and compared with related simulation results. Integrating these gold based PhC structures onto III V semiconductor infrared (IR) photodetectors through a top down approach has promising potential to enhance detector's performance; especially as its wafer scale fabrication method enables the direct adaption to high volume IR detector processing line.", "author_names": [ "Reyhaneh Soltanmoradi", "Q Wang", "Min Qiu", "Jan Y Andersson" ], "corpus_id": 11594844, "doc_id": "11594844", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spectral selectivity of subwavelength gold based photonic crystals on GaAs substrate", "venue": "2013 7th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics", "year": 2013 }, { "abstract": "In this paper, anisotropic graphene plasmonic structures are explored for light trapping and absorption enhancement in surrounding media. It is shown that electrically tunable and versatile spectral and polarization selectivity can be realized. Particularly, it is possible to control absorption of the incident light's polarization component at a specific wavelength by varying the Fermi energy with suitable geometric designs. It may find applications for new types of infrared and THz photodetectors and will promote the research of other novel polarization devices.", "author_names": [ "Wenbin Liu", "Jianfa Zhang", "Zhi Hong Zhu", "Xiaodong Yuan", "Shiqiao Qin" ], "corpus_id": 12300235, "doc_id": "12300235", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Electrically Tunable Absorption Enhancement with Spectral and Polarization Selectivity through Graphene Plasmonic Light Trapping", "venue": "Nanomaterials", "year": 2016 }, { "abstract": "Solar blind detectors based on AlGaN heterostructures grown on sapphire by Molecular Beam Epitaxy and with a dielectric interference filter deposited on the back side are demonstrated to provide record spectral selectivity. Rejection ratios of 2 x 10(4) and better than 5 x 10(4) measured between 280 and 320 nm, are achieved in Metal Semiconductor Metal detectors and Schottky diodes respectively. The whole detector process is fully compatible with low cost array fabrication.", "author_names": [ "J Y Duboz", "Nicolas Grandjean", "Amelie Dussaigne", "Mauro Mosca", "Jean-Luc Reverchon", "Pierre G Verly", "Robert Simpson" ], "corpus_id": 95812902, "doc_id": "95812902", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Solar blind AlGaN photodetectors with a very high spectral selectivity", "venue": "", "year": 2006 }, { "abstract": "Semiconductor based photodetectors (PDs) convert light signals into electrical signals via a photon matter interaction process, which involves surface/interface carrier generation, separation, and transportation of the photo induced charge media in the active media, as well as the extraction of these charge carriers to external circuits of the constructed nanostructured photodetector devices. Because of the specific electronic and optoelectronic properties in the low dimensional devices built with nanomaterial, surface/interface engineering is broadly studied with widespread research on constructing advanced devices with excellent performance. However, there still exist some challenges for the researchers to explore corresponding mechanisms in depth, and the detection sensitivity, response speed, spectral selectivity, signal to noise ratio, and stability are much more important factors to judge the performance of PDs. Hence, researchers have proposed several strategies, including modification of light absorption, design of novel PD heterostructures, construction of specific geometries, and adoption of specific electrode configurations to modulate the charge carrier behaviors and improve the photoelectric performance of related PDs. Here, in this brief review, we would like to introduce and summarize the latest research on enhancing the photoelectric performance of PDs based on the designed structures by considering their surface/interface engineering and how to obtain advanced nanostructured photo detectors with improved performance, which could be applied to design and fabricate novel low dimensional PDs with ideal properties in the near future.", "author_names": [ "Meng Ding", "Zhen Guo", "Xuehang Chen", "Xiaoran Ma", "Lianqun Zhou" ], "corpus_id": 211477538, "doc_id": "211477538", "n_citations": 11, "n_key_citations": 0, "score": 1, "title": "Surface/Interface Engineering for Constructing Advanced Nanostructured Photodetectors with Improved Performance: A Brief Review", "venue": "Nanomaterials", "year": 2020 }, { "abstract": "We first report two dimensional (2D) perovskite Ca2Nb3O10 ultraviolet photodetectors (UV PDs) which are prepared via a facile calcination exfoliation method. The 2D Ca2Nb3O10 PDs demonstrate high performance at 3 V at 280 nm, high responsivity (14.94 A W 1) high detectivity (8.7 x 1013 Jones) high spectral selectivity (R280/R400 8.84 x 103) fast speed (0.08/5.6 ms) and long term stability, exceeding those of most reported UV PDs. Furthermore, the Ca2Nb3O10 PDs integrated with poly(ethylene terephthalate) (PET) show excellent flexibility and have high linear dynamic range (96 dB) Our work provides a general strategy for searching new UV PDs based on numerous layered niobates. The Ca2Nb3O10 nanosheets may be one of the optimum semiconductor materials for next generation high performance UV PDs.", "author_names": [ "Yuchuan Zhang", "Siyuan Li", "Ziliang Li", "Hui Liu", "Xinya Liu", "Jiaxin Chen", "Xiaosheng Fang" ], "corpus_id": 229325737, "doc_id": "229325737", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "High Performance Two Dimensional Perovskite Ca2Nb3O10 UV Photodetectors.", "venue": "Nano letters", "year": 2020 }, { "abstract": "Self powered ultraviolet (UV) photodetectors (PDs) based on ZnO heterojunctions have attracted more attention due to the simple preparation and excellent photoresponse performance without any power supply. The self powered UV PDs based on NiO nanoflakes/ZnO nanorod arrays (NRs) heterojunctions were fabricated by a low cost, simple chemical bath deposition (CBD) method. The crystal quality, optical and electronic properties of ZnO NRs is modified by Al3+ ions additions in the precursor solution. The heterojunction devices with ZnO NRs grown in 0.5% Al3+ ions additions precursor solution exhibit a narrow UV spectral selectivity, high photoresponsivity R (85.12 mA/W) and detectivity D* (1.74 x 1012 cm*Hz1/2/W) and a fast response speed ~2 ms) under 378 nm UV light for low intensity irradiance (0.2 mW/cm2) at zero bias. The large built in electric field of the NiO/ZnO heterojunction with the increased Fermi level of ZnO NRs provide a strong driving force to separate and transfer the photo generated carriers, decrease the recombination of the carriers and then improve the photoresponse performance of heterojunction devices without external bias.", "author_names": [ "Chengtai Wei", "Jianping Xu", "Shaobo Shi", "Yichen Bu", "Rui Cao", "J Chen", "Jinjie Xiang", "Xiaosong Zhang", "Lan Li" ], "corpus_id": 219283937, "doc_id": "219283937", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "The improved photoresponse properties of self powered NiO/ZnO heterojunction arrays UV photodetectors with designed tunable Fermi level of ZnO.", "venue": "Journal of colloid and interface science", "year": 2020 }, { "abstract": "We have explored the operation of resonant cavity light emitting diodes (RC LEDs) used as resonant cavity photodetectors (RC PDs) Our experiments were conducted using a variety of components, operating in diverse wavelength ranges and having different structural characteristics (different distributed Bragg reflector mirror reflectivities, different detuning, etc. The measurements show a clear and systematic angular and spectral dependence of the RC PD photodetected signal. The angular and spectral photosensitivity is derived not only from the quantum well absorption but largely from the microcavity enhancement factor and from the photodetection efficiency condition, which both are dependent on angle and wavelength. The detuning of the microcavity and the extension of the distributed Bragg reflector (DBR) stopband control the extension of the photosensitivity spectral window and the front/top DBR mirror reflectivity controls the angular wavelength selectivity. The fact that the RC PDs' angular and spectral selectivity can be controlled by proper microcavity design, together with their high bandwidth, opens the possibility of using the same RC PD device for detecting different WDM channels.", "author_names": [ "Mihail Dumitrescu", "E -M Pavelescu", "Charis Reith", "Tomi Leinonen", "Mikko Suominen", "M Pessa" ], "corpus_id": 137238174, "doc_id": "137238174", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Angular and spectral selectivity of resonant cavity light emitting diodes used as resonant cavity photodetectors", "venue": "SPIE Photonics Europe", "year": 2004 }, { "abstract": "The performance of self powered UV photodetectors (PDs) without an external power source is far from satisfactory for practical applications. The nanostructure heterojunction based self powered UV PDs can enhance light absorption and provide more interface areas for photogenerated carrier separation. However, they suffer from a large dark current and low signal to noise ratio for carrier recombination due to thermal excitation. The p NiO nanoflakes/n ZnO nanorod array (NR) heterojunctions prepared by chemical bath deposition (CBD) demonstrated good rectifying characteristics and a distinct photovoltaic effect. The UV PDs based on p NiO/n ZnO nanostructure heterojunctions exhibited good spectral selectivity, high responsivity and a fast response speed without an external electric field under weak light radiation. The introduction of an MgO interfacial layer between NiO and ZnO NRs could modify the surface defect states of ZnO NRs and decrease the carrier recombination at the heterojunction interface, enhancing the performance of the self powered UV PDs. The investigation of the energy band structure of the heterojunctions revealed that the self powered photocurrent of the devices is correlated to the built in potential of the heterojunctions. The results demonstrate that the p NiO/n ZnO nanostructure heterojunctions with interfacial layers are promising for the development of self powered visible blind UV PDs with a high performance.", "author_names": [ "Chengtai Wei", "Jianping Xu", "Shaobo Shi", "Rui Cao", "Jing Chen", "Hong Dong", "Xiaosong Zhang", "Shougen Yin", "Lan Li" ], "corpus_id": 198817722, "doc_id": "198817722", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Self powered visible blind UV photodetectors based on p NiO nanoflakes/n ZnO nanorod arrays with an MgO interfacial layer", "venue": "", "year": 2019 }, { "abstract": "In this work a new concept of silicon resonant cavity enhanced photodetector working at 1550 nm has been theoretically investigated. The absorption mechanism is based on the internal photoemission effect through a graphene/silicon Schottky junction incorporated into a silicon based Fabry Perot optical microcavity whose input mirror is constituted by a double silicon on insulator substrate. As output mirror we have investigated two options: a distributed Bragg reflector constituted by some periods of silicon nitride/hydrogenated amorphous silicon and a metallic gold reflector. In addition, we have investigated and compared two configurations: one where the current is collected in the transverse direction with respect to the direction of the incident light, the other where it is collected in the longitudinal direction. We show that while the former configuration is characterized by a better responsivity, spectral selectivity and noise equivalent power, the latter configuration is superior in terms of bandwidth and responsivity x bandwidth product. Our results show responsivity of 0.24 A/W, bandwidth in GHz regime, noise equivalent power of 0.6 nW/cmHz and full with at half maximum of 8.5 nm. The whole structure has been designed to be compatible with silicon technology.", "author_names": [ "Maurizio Casalino" ], "corpus_id": 221656129, "doc_id": "221656129", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Theoretical Investigation of Near Infrared Fabry Perot Microcavity Graphene/Silicon Schottky Photodetectors Based on Double Silicon on Insulator Substrates", "venue": "Micromachines", "year": 2020 }, { "abstract": "In this work we have investigated resonant cavity enhanced (RCE) photodetectors (PDs) exploiting the Internal Photoemission Effect (IPE) through a Single Layer Graphene (SLG) replacing metals in the Silicon (Si) Schottky junctions, operating at 1550 nm. The SLG/Si Schottky junction is incorporated into a Fabry Perot (F P) optical microcavity in order to enhance both the graphene absorption and the responsivity. These devices are provided of high spectral selectivity at the resonance wavelength which can be suitably tuned by changing the length of the cavity. We get a wavelength dependent photoresponse with external responsivity ~20 mA/W in a planar F P microcavity with finesse of 5.4. In addition, in order to increase the finesse of the cavity, and consequently its responsivity, a new device where the SLG has placed in the middle of a Si based F P microcavity has been proposed and theoretically investigated. We have demonstrated that, in a properly designed device, a SLG optical absorption, responsivity and finesse of 100% 0.43 A/W and 172 can be obtained, respectively. Unfortunately, the estimated bandwidth is low due to the planarity of the structure where both Ohmic (AI) and Schottky (SLG) contacts are placed in the same plane. In order to improve the PD bandwidth, we have fabricated and characterized a prototype of a vertical RCE SLG/Si Schottky PD where two contacts are both placed at the edges of a high finesse 200nm thick Si based microcavity. Thanks to this innovative structure an increase of the responsivity bandwidth product is expected. The insights included in this work can open the path for developing of a new family of high performance photodetectors that can find application in silicon photonics.", "author_names": [ "Maurizio Casalino", "Teresa Crisci", "Luigi Moretti", "Mariano Gioffre", "Mario Iodice", "Giuseppe Coppola", "Piera Maccagnani", "Rita Rizzoli", "Filippo Bonafe", "Caterina Summonte", "Vittorio Morandi" ], "corpus_id": 221915902, "doc_id": "221915902", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Silicon Meet Graphene for a New Family of Near Infrared Resonant Cavity Enhanced Photodetectors", "venue": "2020 22nd International Conference on Transparent Optical Networks (ICTON)", "year": 2020 } ]

[ { "abstract": "This paper investigates the opportunity and challenges of 3D silicon photonic electronic integrated circuits (3D EPICs) scaling to wafer scale and beyond. The continuing demand for more data and information is driving new computing, communications, imaging, and information processing at higher throughput and energy efficiency at lower manufacturing cost. The newly developed 3D silicon photonic devices including vertical U turns and vertical lightpipes enable through silicon optical vias (TSOVs) that can interconnect multiple layers of 2D silicon photonic electronic integrated circuits consistently with the industry's through silicon via (TSV) based 3D electronic integrated circuit manufacturing. Heterogeneous integration technology based on transfer printing allows wafer scale (or beyond wafer scale) heterogeneous integration of dissimilar materials (e.g. III V semiconductor layers) on silicon at room temperature and 3D ultrafast laser inscription technologies allow arbitrary optical interfaces for high density input/output between the 3D EPICs and many strands of multi core fibers (MCFs) We will discuss applications in neuromorphic computing, 3D LiDAR, photonic integrated interferometric telescopes, 3D fine grain memory, and 3D processor memory realized by large scale 3D EPICs.", "author_names": [ "Yuchuan Zhang", "Anirban Samanta", "Kuanping Shang", "S J Ben Yoo" ], "corpus_id": 212938325, "doc_id": "212938325", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Scalable 3D Silicon Photonic Electronic Integrated Circuits and Their Applications", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2020 }, { "abstract": "Abstract A silicon 3D detector with a single cell of 50 x 50 m m2 was produced and evaluated for timing applications. The measurements of time resolution were performed for 90Sr electrons with dedicated electronics used also for determining time resolution of Low Gain Avalanche Detectors (LGADs) The measurements were compared to those with LGADs and also simulations. The studies showed that the dominant contribution to the timing resolution comes from the time walk originating from different induced current shapes for hits over the cell area. This contribution decreases with higher bias voltages, lower temperatures and smaller cell sizes. It is around 30 ps for a 3D detector of 50 x 50 m m2 cell at 150 V and 20 degC, which is comparable to the time walk due to Landau fluctuations in LGADs. It even improves for inclined tracks and larger pads composed of multiple cells. A good agreement between measurements and simulations was obtained, thus validating the simulation results.", "author_names": [ "", "David Flores", "Salvador Hidalgo", "Maria Manna", "Igor Mandi'c", "David Quirion", "Giulio Pellegrini", "Marko Zavrtanik" ], "corpus_id": 119254680, "doc_id": "119254680", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Timing performance of small cell 3D silicon detectors", "venue": "Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment", "year": 2019 }, { "abstract": "Hierarchical three dimensional (3D) microstructures integrated with low dimensional nanomaterials can realize novel properties or improved performance. We report a unique conductive and highly ordered 3D silicon micro mesh structure, which is fabricated by standard lithography using a modified plasma etch process. Zinc oxide (ZnO) nanowires are then integrated with the micro mesh, and the density of ZnO nanowires (NWs) can be increased by around one order of magnitude compared with ZnO NWs on a 2D substrate. Owing to the high spatial density of ZnO NWs on the robust 3D silicon micro mesh structures, improved photocatalytic activity and stability can be achieved. A remarkable enhancement of photocurrent response is also observed. The ZnO can be converted into ZnS NWs and 2 ZnO@ZIF 8 as on the micromesh. This method is low cost and compatible with traditional complementary metal oxide semiconductor industries, and provides new possibilities for a wide range of devices based on micro nano electro mechanical and chemical systems.", "author_names": [ "Bingdong Chang", "Yingying Tang", "Mingli Liang", "Henri V Jansen", "Flemming Jensen", "Bo Wang", "Kristian Molhave", "Jorg Hubner", "Hongyu Sun" ], "corpus_id": 139682465, "doc_id": "139682465", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Highly Ordered 3D Silicon Micro Mesh Structures Integrated with Nanowire Arrays: A Multifunctional Platform for Photodegradation, Photocurrent Generation, and Materials Conversion", "venue": "", "year": 2019 }, { "abstract": "Design and manufacturing technology of 3D silicon photonic structures with optical interconnections through microchannel vias interposers were developed. Silicon chips placed over each other were separated by the silicon microchannel vias interposer served as a light waveguide. Light emitting diodes and photodiodes were formed at the inner surfaces of silicon chips from nanostructured silicon clusters embedded into alumina matrix. The developed structure is characterized by the current conversion efficiency of 0.1% and can operate in the GHz frequency range.", "author_names": [ "S K Lazarouk", "A A Leshok", "Tamara A Kozlova", "A V Dolbik", "Le Dinh Vi", "V K Ilkov", "Vladimir A Labunov" ], "corpus_id": 140490212, "doc_id": "140490212", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "3D Silicon Photonic Structures Based on Avalanche LED with Interconnections through Optical Interposer", "venue": "International Journal of Nanoscience", "year": 2019 }, { "abstract": "Abstract Graphite composite electrodes mixed with silicon are proposed as next generation anode material for high energy and high power applications. In order to overcome drawbacks caused by volume changes of silicon particles during electrochemical cycling and to maintain high specific capacities at enhanced C rates, free standing structures are generated on silicon/graphite electrodes by applying ultrafast laser ablation. Electrochemical properties are systematically investigated by means of galvanostatic measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. Cells with structured electrodes exhibit improved battery performances and lithium ion transport kinetics in comparison to cells with unstructured electrodes. Furthermore, the cells with structured electrodes exhibit a lower impedance at fully lithiated state. After cycling, post mortem analysis is performed revealing that the mechanical stress within the electrodes and current collector can be significantly reduced due to laser generated free standing structures.", "author_names": [ "Yijing Zheng", "Hans Juergen Seifert", "Huifeng Shi", "Yuefei Zhang", "Christian Kubel", "Wilhelm Pfleging" ], "corpus_id": 181876520, "doc_id": "181876520", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "3D silicon/graphite composite electrodes for high energy lithium ion batteries", "venue": "Electrochimica Acta", "year": 2019 }, { "abstract": "This paper presents a new version of the 3D mesa \"bridge\" microdosimeter comprised of an array of 4248 silicon cells fabricated on 10 um thick silicon on insulator substrate. This microdosimeter has been designed to overcome limitations existing in previous generation silicon microdosimeters and it provides well defined sensitive volumes and high spatial resolution. The charge collection characteristics of the new 3D mesa microdosimeter were investigated using the ANSTO heavy ion microprobe, utilizing 5.5 MeV He2+ ions. Measurement of microdosimetric quantities allowed for the determination of the Relative Biological Effectiveness of 290 MeV/u and 350 MeV/u 12C heavy ion therapy beams at the Heavy Ion Medical Accelerator in Chiba (HIMAC) Japan. The microdosimetric RBE obtained showed good agreement with the tissue equivalent proportional counter. Utilizing the high spatial resolution of the SOI microdosimeter, the LET spectra for 70 MeV 12C+6 ions, like those present at the distal edge of 290 and 350 MeV/u beams, were obtained as the ions passed through thin layers of polyethylene film. This microdosimeter can provide useful information about the lineal energy transfer (LET) spectra downstream of the protective layers used for shielding of electronic devices for single event upset prediction.", "author_names": [ "Linh T Tran", "Lachlan Chartier", "David Bolst", "Dale A Prokopovich", "Susanna Guatelli", "Marco Petasecca", "Michael L F Lerch", "Mark I Reinhard", "Vladimir L Perevertaylo", "Michael Jackson", "Naruhiro Matsufuji", "D J Hinde", "Mahananda Dasgupta", "Andrew E Stuchbery", "Anatoly B Rosenfeld" ], "corpus_id": 136016136, "doc_id": "136016136", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "3D silicon microdosimetry and RBE study using 12C ion of different energies", "venue": "", "year": 2017 }, { "abstract": "3D silicon pixel detectors have been investigated as radiation hard candidates for the innermost layers of the HL LHC upgrade of the ATLAS pixel detector. 3D detectors are already in use today in the ATLAS IBL and AFP experiments. These are based on 50 x 250 mm2 large pixels connected to the FE I4 readout chip. Detectors of this generation were irradiated to HL LHC fluences and demonstrated excellent radiation hardness with operational voltages as low as 180 V and power dissipation of 12 15 mW/cm2 at a fluence of about 1016 neq/cm2, measured at 25degC. Moreover, to cope with the higher occupancies expected at the HL LHC, a first run of a new generation of 3D detectors designed for the HL LHC was produced at CNM with small pixel sizes of 50 x 50 and 25 x 100 mm2, matched to the FE I4 chip. They demonstrated a good performance in the laboratory and in beam tests with hit efficiencies of about 97% at already 1 2 V before irradiation.", "author_names": [ "J orn Christian Lange", "M Carulla Areste", "E Cavallaro", "Fabian Forster", "Sebastian Grinstein", "I L'opez Paz", "Maria Manna", "Giulio Pellegrini", "David Quirion", "S Terzo", "D V'azquez Furelos" ], "corpus_id": 114617837, "doc_id": "114617837", "n_citations": 21, "n_key_citations": 4, "score": 0, "title": "3D silicon pixel detectors for the High Luminosity LHC", "venue": "", "year": 2016 }, { "abstract": "Abstract Carbon nanotubes have attracted widespread attention as ideal materials for Lithium ion batteries (LIBs) due to their excellent conductivity, mechanical flexibility, chemical stability and extremely large surface area. Here, three dimensional (3D) silicon/carbon nanotube capsule composites (Si/CNCs) are firstly prepared via water in oil (W/O) emulsion technique with more than 75 wt% loading amount of silicon. CNCs with unique hollow sphere structure act as a 3D interconnected conductive network skeleton, and the cross linked carbon nanotubes (CNTs) of CNCs can effectively enhance the strength, flexibility and conductivity of the electrode. This Si/CNCs can not only alleviate the volume expansion, but also effectively improve the electrochemical performance of the LIBs. Such Si/CNCs electrode with the unique structure achieves a high initial discharge specific capacity of 2950 mAh g 1 and retains 1226 mAh g 1 after 100 cycles at 0.5 A g 1 as well as outstanding rate performance of 547 mAh g 1 at 10 A g 1", "author_names": [ "Xinyang Yue", "Wang Sun", "Jing Zhang", "Fang Wang", "Kening Sun" ], "corpus_id": 100425617, "doc_id": "100425617", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Facile synthesis of 3D silicon/carbon nanotube capsule composites as anodes for high performance lithium ion batteries", "venue": "", "year": 2016 }, { "abstract": "Abstract Herein, mesoporous 3D silicon carbide (SiC) carbonitride (Si C N) and nitride (Si3N4) structures have been synthesized by nanocasting and pyrolysis using commercial organosilicon polymers as precursors of the different compositions. Detailed characterizations by BET and XRD allowed us to fix the most appropriate parameters to design mesoporous 3D structures with high specific surface areas and high pore volume. Then, the series of 3D structures has been used as supports to grow platinum nanoparticles (Pt NPs) by wet impregnation followed by reduction in hydrogen/argon flow. The Pt supported mesoporous 3D supports kept the mesoporosity of the virgin supports to be used for catalytic hydrolysis of sodium borohydride (NaBH4) A hydrogen generation rate of 24.2 L min 1 gPt 1 is measured for the Pt supported mesoporous 3D Si3N4 structure, which is notably higher than the catalytic hydrolysis using Pt supported mesoporous 3D SiC and Si C N structures. HRTEM investigations demonstrated the homogeneous distribution of Pt NPs over the Si3N4 support.", "author_names": [ "Abhijeet Lale", "Awin Wasan", "Ravinder Kumar", "Philippe Miele", "Umit B Demirci", "Samuel Bernard" ], "corpus_id": 99966454, "doc_id": "99966454", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Organosilicon polymer derived mesoporous 3D silicon carbide, carbonitride and nitride structures as platinum supports for hydrogen generation by hydrolysis of sodium borohydride", "venue": "", "year": 2016 }, { "abstract": "Abstract Herein, the three dimensional free standing nano silicon soft carbon embedded in graphene scaffold composite is prepared to boost the lithium storage property of the silicon anode. For the aspect of \"single\" the own volume expansion is relieved by the encapsulated soft carbon layer and the soft carbon layer can suppress the repeated formation of solid electrolyte interface films onto the \"single\" silicon nanoparticle (SNP) Moreover, the soft carbon layer possesses alternating amorphous and crystalline regions to provide the rapid lithium ion diffusion channel. On the side of \"monolithic\" the 3D free standing graphene scaffold loading with evenly distributed SNPs eliminates collisions between SNPs during the charging/discharging cycles, and endows the 'monolithic' electrode with excellent electronic conductivity, fast lithium ion diffusion pathway and high SNPs content. Thus, the above composite anode exhibits superior specific capacity, cycling performance and rate performance, such as around 2600 mA h g 1 (8.34 mA h cm 2) of specific capacity at a current density of 0.2 A/g and almost no capacity attenuation after 100 cycles. The design thinking (from 'single' to 'monolithic' paves a new avenue towards high performance anodes of silicon and transition metal oxides.", "author_names": [ "Feng-Xia Wang", "Zhenglong Hu", "Limin Mao", "Jian Mao" ], "corpus_id": 213968908, "doc_id": "213968908", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Nano silicon soft carbon embedded in graphene scaffold: High performance 3D free standing anode for lithium ion batteries", "venue": "", "year": 2020 } ]

[ { "abstract": "Hybrid superconductor semiconductor devices are currently one of the most promising platforms for realizing Majorana zero modes. Their topological properties are controlled by the band alignment of the two materials, as well as the electrostatic environment, which are currently not well understood. Here, we pursue to fill in this gap and address the role of band bending and superconductor semiconductor hybridization in such devices by analyzing a gated single Al InAs interface using a self consistent Schrodinger Poisson approach. Our numerical analysis shows that the band bending leads to an interface quantum well, which localizes the charge in the system near the superconductor semiconductor interface. We investigate the hybrid band structure and analyze its response to varying the gate voltage and thickness of the Al layer. This is done by studying the hybridization degrees of the individual subbands, which determine the induced pairing and effective $g$ factors. The numerical results are backed by approximate analytical expressions which further clarify key aspects of the band structure. We find that one can obtain states with strong superconductor semiconductor hybridization at the Fermi energy, but this requires a fine balance of parameters, with the most important constraint being on the width of the Al layer. In fact, in the regime of interest, we find an almost periodic dependence of the hybridization degree on the Al width, with a period roughly equal to the thickness of an Al monolayer. This implies that disorder and shape irregularities, present in realistic devices, may play an important role for averaging out this sensitivity and, thus, may be necessary for stabilizing the topological phase.", "author_names": [ "August E G Mikkelsen", "Panagiotis Kotetes", "Peter Krogstrup", "Karsten Flensberg" ], "corpus_id": 119185090, "doc_id": "119185090", "n_citations": 57, "n_key_citations": 1, "score": 0, "title": "Hybridization at Superconductor Semiconductor Interfaces", "venue": "", "year": 2018 }, { "abstract": "We demonstrate how to design various nonstandard types of Andreev bound state (ABS) dispersions, via a composite construction relying on Majorana bound states (MBSs) Here, the MBSs appear at the interface of a Josephson junction consisting of two topological superconductors (TSCs) Each TSC harbors multiple MBSs per edge by virtue of a chiral or unitary symmetry. We find that, while the ABS dispersions are 2p periodic, they still contain multiple crossings which are protected by the conservation of fermion parity. A single junction with four interface MBSs and all MBS couplings fully controllable, or networks of such coupled junctions with partial coupling tunability, open the door for topological band structures with Weyl points or nodes in synthetic dimensions, which in turn allow for fermion parity (FP) pumping with a cycle set by the ABS dispersion details. In fact, in the case of nodes, the FP pumping is a manifestation of chiral anomaly in 2D synthetic spacetime. The possible experimental demonstration of ABS engineering in these devices further promises to unveil new paths for the detection of MBSs and higher dimensional chiral anomaly.", "author_names": [ "Panagiotis Kotetes", "M T Mercaldo", "M Cuoco" ], "corpus_id": 201698038, "doc_id": "201698038", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Synthetic Weyl Points and Chiral Anomaly in Majorana Devices with Nonstandard Andreev Bound State Spectra.", "venue": "Physical review letters", "year": 2019 }, { "abstract": "We demonstrate how to design various nonstandard types of Andreev bound state (ABS) dispersions, via a composite construction relying on Majorana bound states (MBSs) Here, the MBSs appear at the interface of a Josephson junction consisting of two topological superconductors (TSCs) Each TSC harbors multiple MBSs per edge, by virtue of a chiral or unitary symmetry. We find that, while the ABS dispersions are $2\\pi$ periodic, they still contain multiple crossings which are protected by the conservation of fermion parity. Considering networks of coupled junctions of this type, opens the door for topological bandstructures with nodes or Weyl points in synthetic dimensions, and the realization of chiral anomaly. The latter, also allows for fermion parity pumping with a cycle set by the ABS dispersion details. The possible experimental demonstration of ABS engineering in these devices, will further unveil new paths for the detection of chiral anomaly and MBSs.", "author_names": [ "Panagiotis Kotetes", "M T Mercaldo", "M Cuoco" ], "corpus_id": 119194952, "doc_id": "119194952", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nonstandard Andreev Bound State Spectra in Majorana Devices and Chiral Anomaly Phenomena in Synthetic Dimensions", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 149586742, "doc_id": "149586742", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Topological insulators in 1+1 dimensions", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 150205337, "doc_id": "150205337", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Topological classification of insulators and beyond", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 149770898, "doc_id": "149770898", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Z2 topological insulators", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 150299840, "doc_id": "150299840", "n_citations": 0, "n_key_citations": 0, "score": 2, "title": "Symmetries and effective Hamiltonians", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 149874620, "doc_id": "149874620", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Chern insulators applications", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 149777417, "doc_id": "149777417", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Electron coupling to external fields and transport theory", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Panagiotis Kotetes" ], "corpus_id": 150138841, "doc_id": "150138841", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Chern insulators fundamentals", "venue": "", "year": 2019 } ]

[ { "abstract": "Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike in conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and valley freedom. The interplay between the two is the focus of this review. The energy levels associated with each degree of freedom, and the spin orbit coupling between them, are explained, together with their consequences for transport measurements through nanotube quantum dots. In double quantum dots, the combination of quantum numbers modifies the selection rules of Pauli blockade. This can be exploited to read out spin and valley qubits and to measure the decay of these states through coupling to nuclear spins and phonons. A second unique property of carbon nanotubes is that the combination of valley freedom and electron electron interactions in one dimension strongly modifies their transport behavior. Interaction between electrons inside and outside a quantum dot is manifested in SU(4) Kondo behavior and level renormalization. Interaction within a dot leads to Wigner molecules and more complex correlated states. This review takes an experimental perspective informed by recent advances in theory. As well as the well understood overall picture, open questions for the field are also clearly stated. These advances position nanotubes as a leading system for the study of spin and valley physics in one dimension where electronic disorder and hyperfine interaction can both be reduced to a low level.", "author_names": [ "E A Laird", "Ferdinand Kuemmeth", "Gary A Steele", "K Grove-Rasmussen", "Jesper Nygaard", "Karsten Flensberg", "L P Kouwenhoven" ], "corpus_id": 119208985, "doc_id": "119208985", "n_citations": 175, "n_key_citations": 8, "score": 1, "title": "Quantum transport in carbon nanotubes", "venue": "", "year": 2015 }, { "abstract": "Abstract The renormalization decimation algorithm (RDA) of Lopez Sancho et al. is used in quantum transport theory to calculate bulk and surface Green's functions. We derive an improved version of the RDA for the case of very long quasi one dimensional unit cells (in transport direction) This covers not only long unit cells but also supercell like calculations for structures with disorder or defects. In such large systems, short range interactions lead to sparse real space Hamiltonian matrices. We show how this and a corresponding subdivision of the unit cell in combination with the decimation technique can be used to reduce the calculation time. Within the resulting algorithm, separate RDA calculations of much smaller effective Hamiltonian matrices must be done for each Green's function, which enables the treatment of systems too large for the common RDA. Finally, we discuss the performance properties of our improved algorithm as well as some exemplary results for chiral carbon nanotubes.", "author_names": [ "Fabian Teichert", "Andreas Zienert", "Jorg Schuster", "Michael Schreiber" ], "corpus_id": 119072952, "doc_id": "119072952", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An improved Green's function algorithm applied to quantum transport in carbon nanotubes", "venue": "Computational Materials Science", "year": 2019 }, { "abstract": "Carbon nanotubes are of central importance for applications in nano electronics thanks to their exceptional transport properties. They can be used as sensors, for example in biological applications, provided that they are functionalized to detect specific molecules. Due to their one dimensional geometry the carbon nanotubes are very sensitive to the phenomenon of Anderson localization and it is therefore essential to know how the functionalization modifies their conduction properties and if they remain good conductors. Here we present a study of the quantum localization induced by functionalization in metallic single walled carbon nanotubes (SWCNT) with circumferences up to 15\\,nm. We consider resonant and non resonant adsorbates that represent two types of covalently functionalized groups with strong and moderate scattering properties. The present study provides a detailed analysis of the localization behaviour and shows that the localization length can decrease down to 20 50\\,nm at concentrations of about 1 percent of adsorbates. On this basis we discuss the possible electronic transport mechanisms which can be either metallic like or insulating like with variable range hopping.", "author_names": [ "Ghassen Jemai", "Jouda Jemaa Khabthani", "Guy Trambly de Laissardiere", "Didier Mayou" ], "corpus_id": 199405506, "doc_id": "199405506", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Quantum localization and electronic transport in covalently functionalized carbon nanotubes.", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2019 }, { "abstract": "We report on quantum transport measurements of a carbon nanotube (CNT) quantum dot that is functionalized with magnetic {Mn4} complexes. The coupling between the spin 5/2 MnII ions within each {Mn4} complex is predominantly antiferromagnetic. Coulomb diamond measurements at T 4 K reveal that the covalent attachment of the complexes to the CNT framework has only little influence on the carbon nanotube quantum dot. Surprisingly, a strong increase of noise is observed upon cooling the sample to T 30 mK. Time traces of the current taken at a diamond edge reveal a random telegraph signal. We attribute this to fluctuations of molecular spin states of the attached {Mn4} complexes.", "author_names": [ "Michael Schnee", "Claire Besson", "Robert Frielinghaus", "Christian Lurz", "Paul Kogerler", "Claus Michael Schneider", "Carola Meyer" ], "corpus_id": 125747898, "doc_id": "125747898", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Quantum transport in carbon nanotubes covalently functionalized with magnetic molecules", "venue": "", "year": 2016 }, { "abstract": "We derive an improved version of the renormalization decimation algorithm (RDA) of L\\'opez Sancho, which is used in quantum transport theory to calculate the bulk and the surface Green's function of a device. We consider the case of very long unit cells (in transport direction) This covers not only long unit cells itself but also supercell like calculations for defective structures. For such large systems, short range interactions lead to a sparse real space Hamiltonian matrix. We show how this and a corresponding subdivision of the unit cell in combination with the decimation technique can be used to previously reduce the system size. The result are separate RDA calculation of much smaller effective Hamiltonian matrices for each Green's function. Finally, we present the performance properties of our improved algorithm as well a some exemplary results for chiral carbon nanotubes.", "author_names": [ "Fabian Teichert", "Andreas Zienert", "Jorg Schuster", "Michael Schreiber" ], "corpus_id": 51685231, "doc_id": "51685231", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An improved scheme for calculating the bulk and surface Green's functions within quantum transport theory for systems with long unit cells: Application to carbon nanotubes", "venue": "", "year": 2018 }, { "abstract": "In the last twenty years, due to technological advances, it has become possible to build, manipulate and observe nanometer structures and so their dimensions are intermediate between the microscopic and macroscopic. These new systems present novel features and have originated the new field of mesoscopic physics As for the transport properties the mesoscopic conductors do not have ohmic behaviour and the free mean path of electrons is longer than the conductor length in some systems. In this case the conductor is called ballistic, i. e. the electron can travel without scattering in the bulk of the conductor. Another significant consequence of the conductor low dimensionality is that its conductanceG I /V is quantized. The current approach to describe these phenomena is the transmission formalism introduced by Landauer: the current through a conductor is given by the probability that an electron can transmit through it [1] Carbon nanotubes (CNT) which are cylindrical macromolecules formed by periodic hexagonal structures of carbon atoms and typically 1 to 5 nm wide and 1 to 10mm long, should be in ideal systems to proof the theories about the mesoscopic transport.The nature of the electronic transport in CNT is intriguing and still a matter of debate, and only a few experiments have shown the conductance quantization in CNT [2, 3] In this work we present new transport data on carbon double wall nanotubes (DWNT) by means of the mechanically controllable break junction (MCBJ) technique [4] We assume that scattering in the bulk is negligible and the number of channels determines the average conductance in the ballistic regime. A major conclusion of our work is the realization that actually there are two types of ballistic pathways in carbon nanotubes networks. Further theoretical and experimental studies at high voltages seems necessary to better understand the DWNT properties.", "author_names": [ "Mark Baxendale", "Mauro Melli", "I E Pollini" ], "corpus_id": 41087220, "doc_id": "41087220", "n_citations": 56, "n_key_citations": 3, "score": 0, "title": "Quantum transport in carbon nanotubes", "venue": "", "year": 2005 }, { "abstract": "We study the transport properties of single walled carbon nanotubes (SWCNTs) using the nonequilibrium Green's function method based on first principles calculations. We compared three SWCNTs with different chiralities (3, 3) (5, 0) and (4, 2) and found that the thermal conductance varies significantly with the chirality, especially at low temperatures. Such differences are attributed to the dependence on the chirality of the frequency of the lowest optical mode and phonon phonon interaction with the semi infinite leads. To obtain accurate low vibrational frequencies, a force constant correction based on the Lagrange undetermined multiplier method was employed. The phonon phonon interaction was analyzed in terms of the projection of the phonon coupling with the semi infinite leads onto the normal modes of the center region. Our result indicates that high optical mode frequency and weak phonon coupling on the armchair (3, 3) SWCNT are the origin of the long quantized plateau found in the experimental thermal conductance.", "author_names": [ "Tomoyuki Hata", "Hiroki Kawai", "Tatsuhiko Ohto", "Koichi Yamashita" ], "corpus_id": 24326190, "doc_id": "24326190", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Chirality dependence of quantum thermal transport in carbon nanotubes at low temperatures: a first principles study.", "venue": "The Journal of chemical physics", "year": 2013 }, { "abstract": "Abstract MnO quantum dots homogenously embedded in carbon nanotubes (denoted as MnO QDs@CNTs) were prepared via a scalable electrospinning technique with LiN 3 serving as poregen agent. The strong N 2 evolution resulting from the explosive decomposition of the porogen LiN 3 and oxidation diffusion of MnCl 2 during the heat treatment are found to be responsible for the formation of the hierarchy structure. As binder free anodes, the composite networks displayed extraordinary LIBs performance with good reversible capacity (as high as ~1100 mAh g 1 at 100 mA g 1 high coulombic efficiency, outstanding rate capability and superior cyclic performance (nearly no capacity fading after 200 cycles at a high current density of 3000 mA g 1 owing to the unique combination of ultra small MnO QDs and stable CNTs with excellent transport properties. This shows MnO QDs@CNTs composites are almost the most efficient MnO based anode materials for LIBs so far.", "author_names": [ "Lijun Zhang", "Guanglin Xia", "Yuqin Huang", "Chenyun Wei", "Yiwei Yu", "Dalin Sun", "Xuebin Yu" ], "corpus_id": 100508073, "doc_id": "100508073", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "MnO quantum dots embedded in carbon nanotubes as excellent anode for lithium ion batteries", "venue": "", "year": 2018 }, { "abstract": "Abstract We present a tutorial introduction into the structure and electronic properties of carbon nanotubes which may serve as an entry point into the literature on the field. Some of the original experiments in the field are selected to illustrate the richness of quantum transport in single and multi wall carbon nanotubes.", "author_names": [ "Elsa Thune", "Christoph Strunk" ], "corpus_id": 118946033, "doc_id": "118946033", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Quantum Transport in Carbon Nanotubes", "venue": "", "year": 2006 }, { "abstract": "We study two conceptually different regimes of electronic transport in carbon nanotubes. In the first part, we analyse spin transport across a carbon nanotube quantum dot coupled to ferromagnetic leads. More specifically, we account for charge fluctuations between the dot and contacts that are sensitive to the ferromagnetic properties of the contacts. This enables us to analyse specific features observed in the differential conductance and the tunnelling magneto resistance data. The agreement between the model output and the experimental data is on a qualitative level. In the second part we study electronic wave interference phenomena, similar to the Fabry Perot interference in optics. We find that the interplay of the trigonal warping of the graphene lattice and the geometry of the carbon nanotube are the key to the interpretation of a superimposed modulation of the differential conductance. We provide a detailed analysis of experimental observations in the transparent regime and extract the chiral angle of the carbon nanotube under investigation.", "author_names": [ "Alois Dirnaichner" ], "corpus_id": 136318908, "doc_id": "136318908", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Charge and spin transport in carbon nanotubes:From Coulomb blockade to Fabry Perot interference", "venue": "", "year": 2017 } ]

[ { "abstract": "The prospect of building quantum circuits1,2 using advanced semiconductor manufacturing makes quantum dots an attractive platform for quantum information processing3,4. Extensive studies of various materials have led to demonstrations of two qubit logic in gallium arsenide5, silicon6 12 and germanium13. However, interconnecting larger numbers of qubits in semiconductor devices has remained a challenge. Here we demonstrate a four qubit quantum processor based on hole spins in germanium quantum dots. Furthermore, we define the quantum dots in a two by two array and obtain controllable coupling along both directions. Qubit logic is implemented all electrically and the exchange interaction can be pulsed to freely program one qubit, two qubit, three qubit and four qubit operations, resulting in a compact and highly connected circuit. We execute a quantum logic circuit that generates a four qubit Greenberger Horne Zeilinger state and we obtain coherent evolution by incorporating dynamical decoupling. These results are a step towards quantum error correction and quantum simulation using quantum dots.", "author_names": [ "Nico W Hendrickx", "W I L Lawrie", "Maximilian Russ", "F van Riggelen", "Sander L de Snoo", "R N Schouten", "Amir Sammak", "Giordano Scappucci", "Menno Veldhorst" ], "corpus_id": 221553537, "doc_id": "221553537", "n_citations": 31, "n_key_citations": 0, "score": 1, "title": "A four qubit germanium quantum processor.", "venue": "Nature", "year": 2021 }, { "abstract": "", "author_names": [ "A J Sigillito", "James Loy", "D M Zajac", "Felix Borjans", "Michael J Gullans", "Jason R Petta" ], "corpus_id": 145851918, "doc_id": "145851918", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Four qubit quantum processor in isotopically enriched silicon", "venue": "", "year": 2019 }, { "abstract": "Universal quantum information processing requires the execution of single qubit and two qubit logic. Across all qubit realizations 1 spin qubits in quantum dots have great promise to become the central building block for quantum computation 2 Excellent quantum dot control can be achieved in gallium arsenide 3 5 and high fidelity qubit rotations and two qubit logic have been demonstrated in silicon 6 9 but universal quantum logic implemented with local control has yet to be demonstrated. Here we make this step by combining all of these desirable aspects using hole quantum dots in germanium. Good control over tunnel coupling and detuning is obtained by exploiting quantum wells with very low disorder, enabling operation at the charge symmetry point for increased qubit performance. Spin orbit coupling obviates the need for microscopic elements close to each qubit and enables rapid qubit control with driving frequencies exceeding 100 MHz. We demonstrate a fast universal quantum gate set composed of single qubit gates with a fidelity of 99.3 per cent and a gate time of 20 nanoseconds, and two qubit logic operations executed within 75 nanoseconds. Planar germanium has thus matured within a year from a material that can host quantum dots to a platform enabling two qubit logic, positioning itself as an excellent material for use in quantum information applications. Spin qubits based on hole states in strained germanium could offer the most scalable platform for quantum computation.", "author_names": [ "Nico W Hendrickx", "David P Franke", "Amir Sammak", "Giordano Scappucci", "Menno Veldhorst" ], "corpus_id": 131775776, "doc_id": "131775776", "n_citations": 84, "n_key_citations": 0, "score": 0, "title": "Fast two qubit logic with holes in germanium", "venue": "Nature", "year": 2020 }, { "abstract": "Shor's quantum algorithm factorizes integers, and implementing this is a benchmark test in the early development of quantum processors. Researchers now demonstrate this important test in a solid state system: a circuit made up of four superconducting qubits factorizes the number 15.", "author_names": [ "Erik Lucero", "Rami Barends", "Yu Chen", "Julian Kelly", "Matteo Mariantoni", "Anthony Megrant", "P J J O'Malley", "Daniel Thomas Sank", "Amit Vainsencher", "J Wenner", "T C White", "Yi Yin", "Andrew N Cleland", "John M Martinis" ], "corpus_id": 44055700, "doc_id": "44055700", "n_citations": 218, "n_key_citations": 4, "score": 0, "title": "Computing prime factors with a Josephson phase qubit quantum processor", "venue": "", "year": 2012 }, { "abstract": "The successful implementation of algorithms on quantum processors relies on the accurate control of quantum bits (qubits) to perform logic gate operations. In this era of noisy intermediate scale quantum (NISQ) computing, systematic miscalibrations, drift, and crosstalk in the control of qubits can lead to a coherent form of error which has no classical analog. Coherent errors severely limit the performance of quantum algorithms in an unpredictable manner, and mitigating their impact is necessary for realizing reliable quantum computations. Moreover, the average error rates measured by randomized benchmarking and related protocols are not sensitive to the full impact of coherent errors, and therefore do not reliably predict the global performance of quantum algorithms, leaving us unprepared to validate the accuracy of future large scale quantum computations. Randomized compiling is a protocol designed to overcome these performance limitations by converting coherent errors into stochastic noise, dramatically reducing unpredictable errors in quantum algorithms and enabling accurate predictions of algorithmic performance from error rates measured via cycle benchmarking. In this work, we demonstrate significant performance gains under randomized compiling for the four qubit quantum Fourier transform algorithm and for random circuits of variable depth on a superconducting quantum processor. Additionally, we accurately predict algorithm performance using experimentally measured error rates. Our results demonstrate that randomized compiling can be utilized to maximally leverage and predict the capabilities of modern day noisy quantum processors, paving the way forward for scalable quantum computing.", "author_names": [ "Akel Hashim", "R K Naik", "A Morvan", "J L Ville", "Bradley Mitchell", "John Mark Kreikebaum", "Marc Grau Davis", "Ethan Smith", "Costin Iancu", "Kevin P O'Brien", "Ian N Hincks", "Joel Wallman", "Joseph Emerson", "Irfan Siddiqi" ], "corpus_id": 222090192, "doc_id": "222090192", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Randomized compiling for scalable quantum computing on a noisy superconducting quantum processor", "venue": "", "year": 2020 }, { "abstract": "In quantum information processing, spin 3/2 electron or nuclear spin states are known as two qubit states. For SI (S 3/2, I 3/2) spin system, there are 16 four qubit states. In this study, first, four qubit entangled states are obtained by using the matrix representation of Hadamard and CNOT logic gates. By considering 75As@C60 molecule as SI (S 3/2, I 3/2) spin system, four qubit entangled states are also obtained by using the magnetic resonance pulse sequences of Hadamard and CNOT logic gates. Then, it is shown that obtained entangled states can be transformed into each other by the transformation operators.", "author_names": [ "A Gun", "Selcuk Cakmak", "Azmi Gencten" ], "corpus_id": 5118689, "doc_id": "5118689", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Construction of four qubit quantum entanglement for SI (S 3/2, I 3/2) spin system", "venue": "Quantum Inf. Process.", "year": 2013 }, { "abstract": "Aluminumgermanium nanowires (NWs) thermal activated solid state reaction is a promising system as very sharp and well defined one dimensional contacts can be created between a metal and a semiconductor, that can become a quantum dot if the size becomes sufficiently small. In the search for high performance devices without variability, it is of high interest to allow deterministic fabrication of nanowire quantum dots, avoiding sample variability and obtaining atomic scale precision on the fabricated dot size. In this paper, we present a reliable fabrication process to produce sub10 nm Ge quantum dots (QDs) using a combination of ex situ thermal annealing via rapid thermal annealing (RTA) and in situ Joule heating technique in a transmission electron microscope (TEM) First we present in situ direct joule heating experiments showing how the heating electrode could be damaged due to the formation of Al crystals and voids at the vicinity of the metal/NW contact, likely related with electro migration phenomena. We show that the contact quality can be preserved by including an additional ex situ RTA step prior to the in situ heating. The in situ observations also show in real time how the exchange reaction initiates simultaneously from several locations underneath the Al contact pad, and the Al crystal grows gradually inside the initial Ge NW with the growth interface along a Ge(111) lattice plane. Once the reaction front moves out from underneath the contact metal, two factors jeopardize an atomically accurate control of the Al/Ge reaction interface. We observed a local acceleration of the reaction interface due to the electron beam irradiation in the transmission electron microscope as well as the appearance of large jumps of the interface in unpassivated Ge wires while a smooth advancement of the reaction interface was observed in wires with an Al2O3 protecting shell on the surface. Carefully controlling all aspects of the exchange reaction, we demonstrate a fabrication process combining ex situ and in situ heating techniques to precisely control and produce axial Al/Ge/Al NW heterostructures with an ultra short Ge segment down to 8 nanometers. Practically, the scaling down of Ge segment length is only limited by the microscope resolution.", "author_names": [ "M A Luonga", "E Robina", "N Paucb", "P Gentileb", "M Sistanic", "A Lugsteinc", "M Spiesd", "B Fernandezd", "M I den Hertogd" ], "corpus_id": 211131994, "doc_id": "211131994", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "In situ high resolution TEM observation of Aluminum solid state diffusion in Germanium nanowires: fabricating sub 10 nm Ge quantum dots", "venue": "", "year": 2020 }, { "abstract": "A comparative analysis is carried out of the growth peculiarities under molecular beam epitaxy of germanium quantum dots on the silicon surfaces with different crystallographic orientations Si(100) and Si(111) including the case of the presence of tin surfactant on the surface. The free energy change, activation barrier of nucleation, critical thickness of the transition from two dimensional growth to three dimensional one, as well as the surface density and size distribution function of quantum dots in these systems are calculated.", "author_names": [ "Andrey P Kokhanenko", "Kirill A Lozovoy", "Alexander V Voitsekhovskii" ], "corpus_id": 125096890, "doc_id": "125096890", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Comparison of the Growth Processes of Germanium Quantum Dots on the Si(100) and Si(111) Surfaces", "venue": "", "year": 2018 }, { "abstract": "Advancing quantum information processing is predicated on the preparation of ever larger multiqubit states. Photonic realizations of such states may be achieved by increasing the number of photons populating the state or the number of qubits encoded per photon. Typical approaches to the latter strategy utilize distinct degrees of freedom of the photon field. We present here an approach that encodes two qubits per photon in the spatial parity of its transverse spatial profile. Simple linear optical devices transform each parity qubit separately or the two qubits jointly. Furthermore, we demonstrate that entangled photon pairs produced by spontaneous parametric down conversion may be used to prepare arbitrary four qubit states through sculpting the spatial profile of the classical optical pump. Two examples are highlighted the preparation of two photon four qubit Greenberger Horne Zeilinger and W states, whose encoding in a photon pair has thus far eluded other approaches.", "author_names": [ "Ayman F Abouraddy", "Timothy M Yarnall", "Giovanni Di Giuseppe", "Malvin Carl Teich", "Bahaa E A Saleh" ], "corpus_id": 16203351, "doc_id": "16203351", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Encoding arbitrary four qubit states in the spatial parity of a photon pair", "venue": "", "year": 2012 }, { "abstract": "In this paper theoretical modeling of formation and growth of germanium silicon quantum dots in the method of molecular beam epitaxy (MBE) on different surfaces is carried out. Silicon substrates with crystallographic orientations (100) and (111) are considered. Special attention is paid to the question of growth of quantum dots on the silicon surface covered by tin, since germanium silicon tin system is extremely important for contemporary nano and optoelectronics: for creation of photodetectors, solar cells, light emitting diodes, and fast speed transistors. A theoretical approach for modeling growth processes of such semiconductor compounds during the MBE is presented. Both layer by layer and island nucleation stages in the Stranski Krastanow growth mode are described. A change in free energy during transition of atoms from the wetting layer to an island, activation barrier of the nucleation, critical thickness of 2D to 3D transition, as well as surface density and size distribution function of quantum dots in these systems are calculated with the help of the established model. All the theoretical speculations are carried out keeping in mind possible device applications of these materials. In particular, it is theoretically shown that using of the Si(100) surface covered by tin as a substrate for Ge deposition may be very promising for increasing size homogeneity of quantum dot array for possible applications in low noise selective quantum dot infrared photodetectors.", "author_names": [ "Kirill A Lozovoy", "Andrey P Kokhanenko", "Alexander V Voitsekhovskii" ], "corpus_id": 13101786, "doc_id": "13101786", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Comparative analysis of germanium silicon quantum dots formation on Si(100) Si(111) and Sn/Si(100) surfaces.", "venue": "Nanotechnology", "year": 2018 } ]

[ { "abstract": "Dye sensitized solar cells based on titanium dioxide (TiO2) are promising low cost alternatives to conventional solid state photovoltaic devices based on materials such as Si, CdTe and CuIn1 xGaxSe2 (refs 1, 2) Despite offering relatively high conversion efficiencies for solar energy, typical dye sensitized solar cells suffer from durability problems that result from their use of organic liquid electrolytes containing the iodide/tri iodide redox couple, which causes serious problems such as electrode corrosion and electrolyte leakage. Replacements for iodine based liquid electrolytes have been extensively studied, but the efficiencies of the resulting devices remain low. Here we show that the solution processable p type direct bandgap semiconductor CsSnI3 can be used for hole conduction in lieu of a liquid electrolyte. The resulting solid state dye sensitized solar cells consist of CsSnI2.95F0.05 doped with SnF2, nanoporous TiO2 and the dye N719, and show conversion efficiencies of up to 10.2 per cent (8.51 per cent with a mask) With a bandgap of 1.3 electronvolts, CsSnI3 enhances visible light absorption on the red side of the spectrum to outperform the typical dye sensitized solar cells in this spectral region.", "author_names": [ "In Jae Chung", "Byunghong Lee", "Jiaqing He", "R P H Chang", "Mercouri G Kanatzidis" ], "corpus_id": 4420558, "doc_id": "4420558", "n_citations": 1303, "n_key_citations": 13, "score": 2, "title": "All solid state dye sensitized solar cells with high efficiency", "venue": "Nature", "year": 2012 }, { "abstract": "Abstract Density functional theory study has been carried out to design a new All Solid State dye sensitized solar cell (SDSC) by applying a donor acceptor conjugated polymer instead of liquid electrolyte. The typical redox mediator (I 1 /I 3 is replaced with a narrow band gap, hole transporting material (HTM) The electronic and optical properties predict that donor and acceptor moieties in the polymeric body have increased the visible light absorption and charge transporting ability, compared to their parent polymers. A unique \"upstairs\" like band energy diagram is created by packing N3 between HTM and TiO 2 Upon light irradiation on the proposed configuration, electrons will move from the dye to TiO 2 and from HTM to dye (to regenerate dye) simultaneously. Our theoretical simulations prove that the proposed configuration will be highly efficient as the HOMO level of HTM is 1.19 eV above the HOMO of sanitizer (dye) providing an efficient pathway for charge transfer. High short circuit current density and power conversion efficiency is promised from the strong overlapping of molecular orbitals of HTM and sensitizer. A low reorganization energy of 0.21 eV and exciton binding energy of 0.55 eV, confirm the high efficiency of HTM. Finally, a theoretical open circuit voltage of 1.49 eV would results high quantum yield while, the chemical stability of HTM towards oxidation can be estimated from its high ionization potential value (4.57 eV)", "author_names": [ "Habib Ullah", "Salma Bibi", "Asif Ali Tahir", "Tapas K Mallick" ], "corpus_id": 55342917, "doc_id": "55342917", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Donor acceptor polymer for the design of All Solid State dye sensitized solar cells", "venue": "", "year": 2017 }, { "abstract": "Figure 1. Chemical structures of the ionic conductors 1 5 (a) and the crystallographic packing structure of conductor 1 (b) Since their discovery by O'Regan and Gratzel in 1991,[1] dyesensitized solar cells (DSSCs) have attracted considerable interest[2] because of their low production cost, high power conversion efficiency (e) and environmental friendliness. Although an e over 11% has been recorded for DSSCs with volatile organic liquid electrolytes,[3] they may be inhibited for outdoor applications in view of the need for robust encapsulation. Therefore, considerable efforts have been devoted to developing solid electrolytes for the fabrication of solid state DSSCs (ssDSSCs)[4 12] However, the efficiency of ssDSSCs is still unsatisfactory compared with liquid junction DSSCs. The low conductivity and/or incomplete filling of solid electrolytes containing a I/I3 redox couple in mesoporous TiO2 films usually lead to a lower shortcircuit photocurrent (Jsc) open circuit photovoltage (Voc) and fill factor (FF)[13,14] Therefore, the development of novel solid electrolytes with high ionic conductivity and good pore filling property is of fundamental importance for highly efficient ssDSSCs. Imidazolium based ionic liquids have been proven to be promising materials as liquid electrolytes for high performance DSSCs because of their wide electrochemical window, high electrical conductivity, negligible vapor pressure, and nontoxicity.[15] However, they are still a type of liquid material and leakage during long term operation is unavoidable. To overcome these shortcomings and retain the advantage of the imidazolium structure, the liquid state phase of imidazolium based ionic liquids has been transformed into a solid state by raising their melting points over room temperature.[16] Unfortunately, the conductivities of the reported imidazolium salts with a solid phase and the efficiencies of their ssDSSCs are still low. In this communication, we report for the first time a novel class of ester functionalized ionic conductors based on an imidazolium cation and iodide anion (Figure 1a) for use in ssDSSCs. Such ester functionalized solid state electrolytes possess advantages over inorganic[17] and organic hole conductors.[18] Firstly, ester functionalized ionic conductors can form a three dimensional (3D) ionic channel of iodides, which is advantageous for fast movement of iodides and charge transfer along the polyiodide chain. Secondly, the coordination interactions between esters and Li+ ions (typically used cations in DSSCs) can form dimers of conductor molecules, and thus the", "author_names": [ "Hong Wang", "Xi Zhang", "Feng Gong", "Gang Zhou", "Zhong-Sheng Wang" ], "corpus_id": 38117565, "doc_id": "38117565", "n_citations": 114, "n_key_citations": 0, "score": 0, "title": "Novel ester functionalized solid state electrolyte for highly efficient all solid state dye sensitized solar cells.", "venue": "Advanced materials", "year": 2012 }, { "abstract": "We applied organic donor p acceptor (D p A) sensitizers for photoelectrochemical polymerization (PEP) because of their appropriate energy levels and high light absorption. The polymerized conducting polymer PEDOT was used as hole conductor in all solid state dye sensitized solar cells (ssDSCs) By combination of the D p A sensitizers and the generated PEDOT from PEP of bis EDOT in acetonitrile, the resulting device showed an average power conversion efficiency of 5.6% Furthermore, the PEP in aqueous micellar electrolytic medium was also employed because of the ability to decrease oxidation potential of the precursor, thereby making the polymerization process easier. The latter method is a cost effective and environmentally friendly approach. Using as hole conductor the so obtained PEDOT from PEP of bis EDOT in aqueous electrolyte, the devices exhibited impressive power conversion efficiency of 5.2% To compare the properties of the generated polymer from bis EDOT in these two PEP methods, electron lifeti.", "author_names": [ "Jinbao Zhang", "Lei Yang", "Yang Shen", "Byung-wook Park", "Yan Hao", "Erik M J Johansson", "Gerrit Boschloo", "Lars Kloo", "Erik O Gabrielsson", "Licheng Sun", "Adel Jarboui", "Christian Perruchot", "Mohamed Soufiane Jouini", "Nick Vlachopoulos", "Anders Hagfeldt" ], "corpus_id": 97756545, "doc_id": "97756545", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Poly(3,4 ethylenedioxythiophene) hole transporting material generated by photoelectrochemical polymerization in aqueous and organic medium for all solid state dye sensitized solar cells", "venue": "", "year": 2014 }, { "abstract": "", "author_names": [ "Emmanuelle Lancelle-Beltran", "Philippe Prene", "Christophe Boscher", "Philippe Belleville", "Pierrick Buvat", "Clement Sanchez" ], "corpus_id": 138764511, "doc_id": "138764511", "n_citations": 112, "n_key_citations": 0, "score": 0, "title": "All Solid State Dye Sensitized Nanoporous TiO2 Hybrid Solar Cells with High Energy Conversion Efficiency+", "venue": "", "year": 2006 }, { "abstract": "", "author_names": [ "Bo Xu", "Haining Tian" ], "corpus_id": 139887388, "doc_id": "139887388", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Performance All Solid State Dye Sensitized Solar Cells", "venue": "", "year": 2018 }, { "abstract": "We report on all solid state dye sensitized solar cells with alkyloxy imidazolium iodide ionic polymer/SiO2 nanocomposite electrolyte and triphenylamine based metal free organic dyes (TC15) By optimizing the content of I2, 1,2 dimethyl 3 propylimidazolium iodide, and SiO2 nanoparticles in the electrolyte, considerable ionic conductivity of 0.151 mS cm 1 is achieved due to the formation of high efficiency electron exchange tunnels. The electrolyte is further characterized by differential scanning calorimetry and scanning electron microscopy (SEM) The result of differential scanning calorimetry shows that the melting temperature of the electrolyte is 120 degC. The SEM analysis reveals a favorable interfacial contact between the electrolyte and the TiO2. The all solid state solar cells with the as prepared alkyloxy imidazolium iodide ionic polymer/SiO2 nanocomposite electrolyte and triphenylamine based metal free organic dyes attains high energy conversion efficiency of 2.70% and 4.12% under the illumination.", "author_names": [ "Jifu Shi", "Leren Wang", "Yanliang Liang", "Shengjie Peng", "Fangyi Cheng", "Jingwei Chen" ], "corpus_id": 97986160, "doc_id": "97986160", "n_citations": 53, "n_key_citations": 1, "score": 0, "title": "All Solid State Dye Sensitized Solar Cells with Alkyloxy Imidazolium Iodide Ionic Polymer/SiO2 Nanocomposite Electrolyte and Triphenylamine Based Organic Dyes", "venue": "", "year": 2010 }, { "abstract": "Ionic liquid polymers, poly(1 alkyl 3 (acryloyloxy)hexylimidazolium iodide) are synthesized and used as mono ion transport electrolytes for all solid state dye sensitized solar cells. For these ionic liquid polymers, imidazolium cations are tethered on polymer main chain and only iodide species is mobile. Such a mono ion transport feature is favorable as solid state electrolyte in dye sensitized solar cells. High thermal stability up to 200 degC for these ionic liquid polymers is confirmed by thermogravimetric analysis. Among these ionic liquid polymers, poly(1 ethyl 3 (acryloyloxy)hexylimidazolium iodide) (PEI) exhibits the highest ionic conductivity (3.63 x 10 4 S cm 1) at room temperature. The dye sensitized solar cell based on PEI electrolyte without the addition of iodine exhibits the open circuit voltage of 838 mV, the short circuit current density of 9.75 mA cm 2 and the conversion efficiency of 5.29% measured at AM 1.5 illumination (100 mW cm 2) Incorporating iodine into PEI electrolyte results in the decrease of both the open circuit voltage and the photocurrent density due to the visible light adsorption by iodine and the enhancement of the recombination between conduction band electrons and the triiodide.", "author_names": [ "Guiqiang Wang", "Shuping Zhuo", "Liang Wang", "Shi-bi Fang", "Yuan Lin" ], "corpus_id": 97953720, "doc_id": "97953720", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Mono ion transport electrolyte based on ionic liquid polymer for all solid state dye sensitized solar cells", "venue": "", "year": 2012 }, { "abstract": "Organic ionic crystals carrying 4 cyano 4' hydroxybiphenyl and imidazolium units were synthesized and applied as the electrolytes for dye sensitized solar cells (DSSCs) The fabricated all solid state DSSCs achieved a cell efficiency of ~5.11% at 55 degC under the simulated air mass 1.5 solar spectrum illuminations at 100 mW cm 2 because of the enhanced light harvesting capability of the electrolyte. To further improve the cell efficiency, 1 propyl 3 methylimidazolium iodine (PMII) was added into the electrolytes as a crystal growth inhibitor. These fabricated devices showed an enhanced power conversion efficiency (PCE) of ~6.55% at 45 degC under the simulated air mass 1.5 solar spectrum illuminations at 50 mW cm 2, and a superior long term stability. The cyanobiphenyl functionalized ionic crystal based electrolytes have expanded our vision to explore new types of all solid state electrolytes for high efficiency DSSCs.", "author_names": [ "Huizi Cao-Cen", "Jie Zhao", "Lihua Qiu", "Dan Xu", "Qing Li", "Xiaojian Chen", "Feng Yan" ], "corpus_id": 96808298, "doc_id": "96808298", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "High performance all solid state dye sensitized solar cells based on cyanobiphenyl functionalized imidazolium type ionic crystals", "venue": "", "year": 2012 }, { "abstract": "An organic ionic crystal, 1 methyl 3 acetyl imidazolium iodide (MA II) was synthesized and applied into all solid state dye sensitized solar cells as electrolyte material. We adopted 1 methyl 3 propylimidazolium tetra fluoroborate as a crystal growth inhibitor, lithium bis trifluoro methanesulfonylimide as a charge transport enhancer, and 4 tert butyl pyridine as a carrier recombination inhibitor. The solar cell devices achieved the total conversion efficiencies of 2.6 and 2.0% under half a sun and one sun irradiation, respectively, showing a good stability even without any sealing and protection from ambient condition. The inner work mechanism of solar cell devices was analyzed by measuring the photovoltage, photocurrent transients, and the electrochemical impedance spectra. The results indicated that target solid state materials from liquid molten salts can be obtained ultimately through molecular design and adjustments of molecular structure, which can be used effectively in photoelectrical devices.", "author_names": [ "Yong Zhao", "Jin Zhai", "Jinling He", "Xiao Chen", "Li Chen", "Libing Zhang", "Yuxi Tian", "Lei Jiang", "Daoben Zhu" ], "corpus_id": 42448045, "doc_id": "42448045", "n_citations": 74, "n_key_citations": 1, "score": 0, "title": "High Performance All Solid State Dye Sensitized Solar Cells Utilizing Imidazolium Type Ionic Crystal as Charge Transfer Layer", "venue": "", "year": 2008 } ]

[ { "abstract": "Perovskite Photovoltaics For many types of low cost solar cells, including those using dye sensitized titania, performance is limited by low open circuit voltages. Lee et al. (p. 643, published online 4 October; see the Perspective by Norris and Aydil) have developed a solid state cell in which structured films of titania or alumina nanoparticles are solution coated with a lead halide perovskite layer that acts as the absorber and n type photoactive layer. These particles are coated with a spirobifluorene organic hole conductor in a solar cell with transparent oxide and metal contacts. For the alumina particles, power conversion efficiencies of up to 10.9% were obtained. Mesostructured alumina acts as an insulating scaffold for the assembly of very thin films of n and p type semiconductors. The energy costs associated with separating tightly bound excitons (photoinduced electron hole pairs) and extracting free charges from highly disordered low mobility networks represent fundamental losses for many low cost photovoltaic technologies. We report a low cost, solution processable solar cell, based on a highly crystalline perovskite absorber with intense visible to near infrared absorptivity, that has a power conversion efficiency of 10.9% in a single junction device under simulated full sunlight. This \"meso superstructured solar cell\" exhibits exceptionally few fundamental energy losses; it can generate open circuit photovoltages of more than 1.1 volts, despite the relatively narrow absorber band gap of 1.55 electron volts. The functionality arises from the use of mesoporous alumina as an inert scaffold that structures the absorber and forces electrons to reside in and be transported through the perovskite.", "author_names": [ "Michael M Lee", "Joel Teuscher", "Tsutomu Miyasaka", "Takurou N Murakami", "Henry J Snaith" ], "corpus_id": 37971858, "doc_id": "37971858", "n_citations": 7384, "n_key_citations": 55, "score": 1, "title": "Efficient Hybrid Solar Cells Based on Meso Superstructured Organometal Halide Perovskites", "venue": "Science", "year": 2012 }, { "abstract": "Recently, inorganic and hybrid light absorbers such as quantum dots and organometal halide perovskites have been studied and applied in fabricating thin film photovoltaic devices because of their low cost and potential for high efficiency. Further boosting the performance of solution processed thin film solar cells without detrimentally increasing the complexity of the device architecture is critically important for commercialization. Here, we demonstrate photocurrent and efficiency enhancement in meso superstructured organometal halide perovskite solar cells incorporating core shell Au@SiO2 nanoparticles (NPs) delivering a device efficiency of up to 11.4% We attribute the origin of enhanced photocurrent to a previously unobserved and unexpected mechanism of reduced exciton binding energy with the incorporation of the metal nanoparticles, rather than enhanced light absorption. Our findings represent a new aspect and lever for the application of metal nanoparticles in photovoltaics and could lead to facile tuning of exciton binding energies in perovskite semiconductors.", "author_names": [ "Wei Zhang", "Michael Saliba", "Samuel D Stranks", "Yao Sun", "Xian Shi", "Ulrich B Wiesner", "Henry J Snaith" ], "corpus_id": 37918428, "doc_id": "37918428", "n_citations": 435, "n_key_citations": 3, "score": 0, "title": "Enhancement of perovskite based solar cells employing core shell metal nanoparticles.", "venue": "Nano letters", "year": 2013 }, { "abstract": "To date, numerous approaches have been developed for fabricating high quality organometal halide perovskite thin films, however, perovskite films obtained by such methods reveal a brown or dark brown color, which might restrain their light absorption ability. Here we report a route to synthesize dark blue mirror like perovskite dense films via a two step spin coating process assisted by treatment of nonpolar solvent scouring. Photovoltaic cells based on such dark blue films demonstrate a high short circuit current density (Jsc) of ~23 mA cm 2 and a power conversion efficiency (PCE) of 16.1% Our method would provide a new candidate method for the fabrication of perovskite solar cells with high performance.", "author_names": [ "Jianhang Qiu", "Wang Gaoxiang", "Wenjing Xu", "Jin Qun", "Lusheng Liu", "Bing-Ping Yang", "Tai Kaiping", "Anyuan Cao", "Xin Jiang" ], "corpus_id": 56339157, "doc_id": "56339157", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Dark blue mirror like perovskite dense films for efficient organic inorganic hybrid solar cells", "venue": "", "year": 2016 }, { "abstract": "For efficient hybrid solar cells based on organometal halide perovskites, the real origin of the I V hysteresis became a big issue and has been discussed widely. In this study, simulated I V curves.", "author_names": [ "Ludmila Cojocaru", "Satoshi Uchida", "P V V Jayaweera", "Shoji Kaneko", "Jotaro Nakazaki", "Takaya Kubo", "Hiroshi Segawa" ], "corpus_id": 98707369, "doc_id": "98707369", "n_citations": 78, "n_key_citations": 0, "score": 0, "title": "Origin of the Hysteresis in I V Curves for Planar Structure Perovskite Solar Cells Rationalized with a Surface Boundary induced Capacitance Model", "venue": "", "year": 2015 }, { "abstract": "Organometal halide perovskites are promising solar cell materials for next generation photovoltaic applications. The long carrier lifetime and diffusion length of these materials make them very attractive for use in light absorbers and carrier transporters. While these aspects of organometal halide perovskites have attracted the most attention, the consequences of the Rashba effect, driven by strong spin orbit coupling, on the photovoltaic properties of these materials are largely unexplored. In this work, taking the electronic structure of methylammonium lead iodide as an example, we propose an intrinsic mechanism for enhanced carrier lifetime in 3D Rashba materials. Based on first principles calculations and a Rashba spin orbit model, we demonstrate that the recombination rate is reduced due to the spin forbidden transition. These results are important for understanding the fundamental physics of organometal halide perovskites and for optimizing and designing the materials with better performance. The proposed mechanism including spin degrees of freedom offers a new paradigm of using 3D Rashba materials for photovoltaic applications. The organometal halide perovskites (OMHPs) have attracted significant attention due to the rapid increase in their photovoltaic power conversion efficiency. In the past 2 years, the reported efficiency of OMHP based solar cells has almost doubled from 9.7%1 to over 20%,2 4 making OHMPs very promising for low cost and high efficiency photovoltaics. Methylammonium lead iodide, CH3NH3PbI3 (MAPbI3) and other closely related hybrid perovskites such as Cl doped and Br doped MAPbI3 (MAPbI3 xClx and MAPbI3 xBrx) (NH2)2CHPbI3 (formamidinium lead iodide, FAPbI3) and Sn doped MAPbI3 (MAPbxSn1 xI3) all display band gaps (1.1 to 2.1 eV) in the visible light region, favorable for photovoltaic applications.5 13 The class of materials also possesses strong light absorption, fast charge generation and high carrier mobility.14,15 In particular, exceptionally long carrier lifetime and diffusion length have been observed in MAPbI3 and MAPbI3 xClx, making them better solar cell candidates than other semiconductors with similar band gaps and absorption coefficients.16 18 Intense research has been directed toward understanding and further enhancing the long carrier lifetime and diffusion length in OMHPs. Previous studies reported a relatively low defect 2 concentration in MAPbI3, which reduces the scattering centers for nonradiative charge carrier recombination. Recently, it has been suggested that the spatial carrier segregation caused by disorder induced localization24 or domains acting as internal p n junctions25 27 may reduce the recombination rate. Though many of the OMHPs are 3D Rashba materials driven by strong spin orbit coupling (SOC) and bulk ferroelectricity,28 31 the effects of spin and orbital degrees of freedom on photovoltaic applications are largely unexplored beyond band gap engineering.29 In this work, we focus on an intrinsic mechanism for the enhancement of long carrier lifetime due to the Rashba splitting. Using first principles calculations and effective models, we find that the Rashba splitting arising from SOC under inversion symmetry breaking can result in spin allowed and spin forbidden recombination channels. The spin forbidden recombination path has a significantly slower transition rate due to the mismatch of spin and momentum. The spin allowed recombination path, though kinetically favorable, can be suppressed under appropriate spin texture due to the low population of free carriers. Taking the electronic structures of MAPbI3 under various distortions as examples, we show that the proposed mechanism is possible under room temperature, and is potentially responsible for the long carrier lifetime in OMHPs. This spindependent recombination mechanism highlights the possibility of using 3D Rashba materials for efficient photovoltaic applications. Fig. 1 illustrates the mechanism for enhancing the carrier lifetime in a generic 3D Rashba material. The strong spin orbit coupling effect from heavy elements (e.g. Pb, Sn, I and Br) and the polar distortion (e.g. aligned molecular dipoles in OMHPs) give rise to the Rashba effect, which lifts the two fold degeneracy of bands near the band gap. Near the band gap, the spin degeneracies of the conduction and valence bands are lifted, giving rise to \"inner\" and \"outer\" bands with opposite spin textures, characterizing spin rotation direction as \"clockwise\" (kh 1) and \"counterclockwise\" (kh +1) (Fig. 1) The photo excitation process creates free electrons and holes, which can quickly relax to band extrema in the presence of inelastic phonon scattering. When the spin textures of conduction band minimum (CBM) and valence band maximum (VBM) are opposite, the radiative recombination of Ckh= 1 Vkh=+1 is a spin forbidden transition due", "author_names": [ "Fan Zheng", "Liang Z Tan", "Shi Liu", "Andrew M Rappe" ], "corpus_id": 119239379, "doc_id": "119239379", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Rashba Spin Orbit Coupling Enhanced Carrier Lifetime in Organometal Halide Perovskites", "venue": "", "year": 2015 }, { "abstract": "Hybrid solar cells based on organometal halide perovskite absorbers have recently emerged as promising class for cost and energy efficient photovoltaics. So far, unraveling the morphology of the different materials within the nanostructured absorber layer has not been accomplished. Here, we present the first visualization of the mesoporous absorber layer in a perovskite solar cell from analytical transmission electron microscopy studies. Material contrast is achieved by electron spectroscopic imaging. We found that infiltration of the hole transport material into the scaffold is low and inhomogeneous. Furthermore, our data suggest that the device performance is strongly affected by the morphology of the TiO2 scaffold with a fine grained structure being disadvantageous.", "author_names": [ "Diana Nanova", "Anne Katrin Kast", "Martin Pfannmoller", "Christian Muller", "Lisa Veith", "Irene Wacker", "Michaela Agari", "Wilfried Hermes", "Peter Erk", "Wolfgang Kowalsky", "Rasmus R Schroder", "Robert Lovrincic" ], "corpus_id": 5163852, "doc_id": "5163852", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "Unraveling the nanoscale morphologies of mesoporous perovskite solar cells and their correlation to device performance.", "venue": "Nano letters", "year": 2014 }, { "abstract": "Hybrid perovskites have recently seen an unprecedented improvement in the power conversion efficiency in photovoltaics devices, and therefore are very promising materials for developing efficient and low cost single junction solar cells [1 3] However, a critical issue is the limited understanding of the correlation between the degree of crystallinity and the emergent perovskite/hole (or electron) transport layer on device performance as well as photo stability. Los Alamos National laboratory (LANL) developed an efficient growth procedure for 3D halide perovskites in inverted perovskite cell architecture using PEDOT PSS as a p type hole transporting material (HTM) [4] The initial collaboration between FOTON/ISCR and LANL led to the observation of a reversible self healing mechanism under light soaking [5] and showed that the aging of the precursor solution plays a role in the nucleation of the perovskite crystallites [6] In this study, we show that growth of methylammonium lead perovskites (MAPbI3) on nickel oxide (NiO) HTM, results in the formation of ordered and crystalline thin films with enhanced crystallinity, leading to characteristic XRD Bragg peak width reminiscent of exclusively observed in the tetragonal phase in single crystals. Photo physical and interface sensitive measurements reveal a reduced trap density at the MAPbI3 perovskite/NiO interface in comparison with perovskites grown on PEDOT: PSS. Photovoltaic cells exhibit a high open circuit voltage (1.12 V) indicating a nearideal energy band alignment. Moreover, we observe photo stability of photovoltaic devices up to 10 Suns, which is a direct result of the enhanced crystallinity of perovskite thin films on NiO. These results elucidate the critical role of the quality of the perovskite/HTL interface in rendering highperformance and photo stable optoelectronic devices [7] [1] Lee, M. M. Teuscher, J. Miyasaka, T. Murakami, T. N. Snaith, H. J. \"Efficient Hybrid Solar Cells Based on Meso Superstructured Organometal Halide Perovskites\" Science 338, 643 (2012) [2] Burschka, J. et al. \"Sequential deposition as a route to high performance perovskitesensitized solar cells\" Nature 499, 316 319 (2013) [3] Jeon, N. J. et al. \"Solvent engineering for high performance inorganic organic hybrid perovskite solar cells\" Nat. Mater. 13, 897 903 (2014) [4] Nie, W. et al, \"High efficiency solution processed perovskite solar cells with millimeterscale grains\" Science 347, 522 (2015) [5] Nie, W. et al, \"Light activated photocurrent degradation and self healing in perovskite solar cells\" Nat. Comm. 7, 11574 (2016) [6] Tsai, H. et al,\" Effect of Precursor Solution Aging on the Crystallinity and Photovoltaic Performance of Perovskite Solar Cells\" Adv. Ener. Mat. 7, 1602159 (2017) [7] Nie, W. et al, Adv. Mater. (In press)", "author_names": [ "Olivier Durand", "Wanyi Nie", "Hsinhan Tsai", "Reza Asadpour", "Jean-Christophe Blancon", "Fangze Liu", "Constantinos C Stoumpos", "Joseph W Strzalka", "Jared J Crochet", "Pulickel M Ajayan", "Boubacar Traore", "Mikael Kepenekian", "Claudine Katan", "Sergei Tretiak", "Mercouri G Kanatzidis", "Muhammad A Alam", "Jacky Even", "Aditya D Mohite" ], "corpus_id": 105191302, "doc_id": "105191302", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Critical role of Interface and perovskite lattice in high efficiency and photostable solar cells", "venue": "", "year": 2017 }, { "abstract": "Due to their outstanding optical properties and superior charge carrier mobilities, organometal halide perovskites have been widely investigated in photodetection and solar cell areas. In perovskites photodetection devices, their high optical absorption and excellent quantum efficiency contribute to the responsivity, even the specific detectivity. In this work, we developed a lateral phototransistor based on mesoscopic graphene/perovskite heterojunctions. Graphene nanowall shows a porous structure, and the spaces between graphene nanowall are much appropriated for perovskite crystalline to mount in. Hot carriers are excited in perovskite, which is followed by the holes' transfer to the graphene layer through the interfacial efficiently. Therefore, graphene plays the role of holes' collecting material and carriers' transporting channel. This charge transfer process is also verified by the luminescence spectra. We used the hybrid film to build phototransistor, which performed a high responsivity and specific detectivity of 2.0 x 103 A/W and 7.2 x 1010 Jones, respectively. To understand the photoconductive mechanism, the perovskite's passivation and the graphene photogating effect are proposed to contribute to the device's performance. This study provides new routes for the application of perovskite film in photodetection.", "author_names": [ "Dahua Zhou", "Leyong Yu", "Peng-Li Zhu", "Hongquan Zhao", "Shuanglong Feng", "Jun Shen" ], "corpus_id": 232383548, "doc_id": "232383548", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Lateral Structured Phototransistor Based on Mesoscopic Graphene/Perovskite Heterojunctions", "venue": "Nanomaterials", "year": 2021 }, { "abstract": "A sensitized solar cell introduced by O'Regan and Gratzel in 1991 was one of the milestones in third generation hybrid solar cells because of the novelty of its architecture, ease of its fabrication, cost effectiveness and good efficiency. Despite persistent efforts made by various groups around the world for over 20 years, the efficiency of DSSCs had not crossed 13% Very recently however, a major path breaking advance has been realized in the domain of solid state sensitized solar cells with the introduction of organometal halide perovskites as efficient alternatives to liquid electrolyte based DSSCs. These new systems have already shown efficiency values of about 15 16% and hold great promise for even higher efficiency (20% at lower cost. Interestingly, the optoelectronic properties of organometal halide perovskites can be tuned by varying the organic cation sizes, metal ions, or the halide anions. Several research groups have shown that complete replacement of I with other halide ions such as Br or Cl leads to increase in the energy gap and therefore lower photocurrents and efficiency. However the presence of mixed halides in the perovskite structure such as CH3NH3PbI2Cl can lead to higher photovoltaic performance because of the increase in the carrier diffusion length (B1 mm) without an appreciable increase in the band gap. Chung et al. showed that doping inorganic perovskite CsSnI3 with 5% fluorine could dramatically improve the photocurrent density by nearly 40% However, to the best of our knowledge, there are no reports of mixed halide organometal perovskite systems with I and F ions applied in solar cells. Importantly, Mosconi et al. have shown that the mixed halide perovskite system consists of two different structures whose stability decreases from I to F along the column VIIA in the periodic table. Therefore it is difficult to stabilize I and F based mixed halide perovskite systems. Herein, we report an interesting strategy to incorporate fluoride ions in the perovskite structure via partial substitution of I by BF4 Importantly, I and BF4 both have nearly the same ionic radius, which makes the incorporation of BF4 feasible in the structure. We further show that I and BF4 based mixed halide perovskite possesses an order of magnitude higher low frequency conductivity than I based perovskite without an appreciable change in the absorption onset. In order to incorporate BF4 within the perovskite structure, the organic salt CH3NH3BF4 was prepared using methylamine and tetrafluoroboric acid solutions. The hybrid perovskite films were prepared using chemical vapor deposition of organic salt CH3NH3BF4 on preheated PbI2 films whereas the powder of hybrid perovskite was prepared using the solid state route with a mixture of organic salt and PbI2. The detailed experimental procedure is given in the ESI. The phase of the synthesized perovskite was confirmed using X ray diffraction measurements. Fig. 1(a) shows the XRD pattern of synthesized CH3NH3PbI(3 x)(BF4)x perovskite film on glass. The crystal structure of CH3NH3PbI(3 x)(BF4)x perovskite is found to be identical to the conventional CH3NH3PbI3 tetragonal perovskite structure as indicated by the appearance of peaks at 14.01, 28.31, 31.81 and 43.21 for the (110) (220) (310) and (330) planes, respectively. The presence of sharp peaks in the X ray diffraction pattern indicates the highly crystalline nature of the perovskite film. In order to confirm the presence of BF4 groups in the perovskite structure, we carried out the ATR FTIR study of the CH3NH3PbI(3 x)(BF4)x films on glass. Fig. 1(b) shows the characteristic stretching vibration peaks of BF4 at 1135 cm 967 cm 524 cm 1084 cm 952 cm 1 (for symmetric stretching) and 1053 cm 1 (B F stretching) which are otherwise absent in the CH3NH3PbI3 perovskite. a Centre of Excellence in Solar Energy, National Chemical Laboratory (CSIR NCL) Dr. Homi Bhabha Road, Pune, India b Academy of Scientific and Innovative Research (AcSIR) Network Institute of Solar Energy (CSIR NISE) New Delhi, India. E mail: [email protected], [email protected] Electronic supplementary information (ESI) available: Experimental details and Fig. S1 S4. See DOI: 10.1039/c4cc04537h Received 15th June 2014, Accepted 4th July 2014", "author_names": [ "Satyawan Nagane", "Umesh Pandharinath Bansode", "Onkar S Game", "Shraddha Y Chhatre", "" ], "corpus_id": 115151000, "doc_id": "115151000", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "CH 3 NH 3 PbI 3 x BF 4 x molecular ion substituted hybrid perovskite", "venue": "", "year": 2014 }, { "abstract": "While the field of perovskite based optoelectronics has mostly been dominated by photovoltaics, light emitting diodes and transistors, semiconducting properties peculiar to perovskites make them interesting candidates for innovative and disruptive applications in light signal detection. Perovskites combine effective light absorption in the broadband range with good photo generation yield and high charge carrier mobility, which combination provides promising potential for exploiting sensitive and fast photodetectors that are targeted for image sensing, optical communication, environmental monitoring, or chemical/biological detection. Currently, organic inorganic hybrid and all inorganic halide perovskites with controlled morphologies of polycrystalline thin films, nano particles/wires/sheets, and bulk single crystals have shown key figure of merit features in terms of their responsivity, detectivity, noise equivalent power, linear dynamic range, and response speed. The sensing region has been covered from ultraviolet visible near infrared (UV Vis NIR) to gamma photons, based on two or three terminal device architectures. Diverse photoactive materials and devices with superior optoelectronic performances have stimulated attention from researchers in multidisciplinary areas. We offer a comprehensive overview of the recent progress of perovskite based photodetectors, focusing on versatile compositions, structures, and morphologies of constituent materials, and diverse device architectures toward the superior performance metrics. Combining the advantages of both organic semiconductors (facile solution processability) and inorganic semiconductors (high charge carrier mobility) perovskites are expected to replace commercial silicon for future photodetection applications. The optical and electronic properties of noble metallic nanoparticles can be exploited to enhance the performance of inorganic/organic photodetectors. We integrated a uniformly distributed layer of Au nanorods (AuNRs) into vertically structured perovskite photoconductive photodetectors and report, as a result, perovskite AuNR hybrid photodetectors that exhibit significant photocurrent enhancements. Ultimately it achieves a responsivity of ~320 A/W at a low driving voltage of 1 V. This is an improvement of 60% compared to the responsivity of pristine devices ~200 A/W) The high responsivity and low driving voltage place this device among the highest performing perovskite based thin film photoconductive photodetectors reported. We characterized the stability and linearity of the photoresponse following repeated light/dark cycles. The hybrid device also shows a fast response (with the decay time of ~95 ns) compared to pristine devices ~230 ns) The improvements in photodetection performance are attributed to plasmon enhanced optical absorption, as well as advances in charge extraction and transport. Metal halide perovskites have rapidly advanced thin film photovoltaic performance; as a result, the materials' ob served instabilities urgently require a solution. Using density functional theory (DFT) we show that a low energy of formation, exacerbated in the presence of humidity, explains the propensity of perovskites to decompose back into their precursors. We find, also using DFT, that intercalation of phenylethylammonium between perovskite layers in troduces quantitatively appreciable van der Waals interactions; and these drive an increased formation energy and should therefore improve material stability. Here we report the reduced dimensionality (quasi 2D) perovskite films that exhibit improved stability while retaining the high performance of conventional three dimensional perovskites. Continuous tuning of the dimensionality, as assessed using photophysical studies, is achieved by the choice of stoi chiometry in materials synthesis. We achieve the first certified hysteresis free solar power conversion in a planar per ovskite solar cell, obtaining a 15.3% certified PCE, and observe greatly improved performance longevity. The same protocol was applied to develop highly stable and efficient photodectors in diverse device configurations. Organometal halide perovskites exhibit large bulk crystal domain sizes, rare traps, excellent mobilities, and carriers that are free at room temperature properties that support their excellent performance in charge separating devices. In devices that rely on the forward injection of electrons and holes, such as light emitting diodes (LEDs) excellent mobilities contribute to the efficient capture of nonequilibrium charge carriers to rare nonradiative centres. Moreover, the lack of bound excitons weakens the competition of desired radiative over undesired nonradiative recombination. Here we also report a perovskite mixed material, one comprised of a series of differently quantum size tuned grains, that funnels photoexcitations to the lowest bandgap light emitter in the mixture. The materials function as charge carrier concentrators, ensuring that radiative recombination successfully outcompetes trapping and hence nonradiative recombination. We use the new material to build devices that exhibit an external quantum efficiency (EQE) of 8.8% and a radiance of 80 Wsr 1m 2. These represent the brightest and most efficient solution processed near infrared LEDs to date. Here we show that, by concentrating photoexcited states into a small subpopulation of radiative domains, one can achieve a high quantum yield even at low excitation intensities. We tailor the composition of quasi 2D perovskites to direct the energy transfer into the lowest bandgap minority phase, and to do so faster than it is lost to non radiative centres. The new material exhibits 60% photoluminescence quantum yield at excitation intensities as low as 1.8 mW/cm2, yielding a ratio of quantum yield to excitation intensity of 0.3 cm2/mW; this represents a two orders of magnitude decrease in the excitation power required to reach high efficiency compared to the best prior reports. Using this strategy, we report LEDs with EQEs of 7.4% and a high luminescence of 8400 cd/m2.", "author_names": [ "Dong Ha Kim", "Huan Mei Wang", "Ju Won Lim", "Li Na Quan", "Ilgeum Lee", "Edward H Sargent" ], "corpus_id": 139769290, "doc_id": "139769290", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optoelectronic hybrid perovskite materials and devices (Conference Presentation)", "venue": "", "year": 2018 } ]

[ { "abstract": "High index dielectric and semiconductor nanoparticles supporting strong electric and magnetic resonances have drawn significant attention in recent years. However, until now, there have been no experimental reports of lasing action from such nanostructures. Here, we demonstrate directional lasing, with a low threshold and high quality factor, in active dielectric nanoantenna arrays achieved through a leaky resonance excited in coupled gallium arsenide (GaAs) nanopillars. The leaky resonance is formed by partially breaking a bound state in the continuum generated by the collective, vertical electric dipole resonances excited in the nanopillars for subdiffractive arrays. We control the directionality of the emitted light while maintaining a high quality factor (Q 2,750) The lasing directivity and wavelength can be tuned via the nanoantenna array geometry and by modifying the gain spectrum of GaAs with temperature. The obtained results provide guidelines for achieving surface emitting laser devices based on active dielectric nanoantennas that are compact and highly transparent.Active dielectric nanoantenna arrays exhibit low threshold and high quality factor directional lasing achieved via a leaky resonance excited in coupled gallium arsenide (GaAs) nanopillars.", "author_names": [ "Son Tung Ha", "Yuan Hsing Fu", "Naresh Kumar Emani", "Zhenying Pan", "Reuben M Bakker", "Ramon Paniagua-Dominguez", "Arseniy I Kuznetsov" ], "corpus_id": 52049890, "doc_id": "52049890", "n_citations": 187, "n_key_citations": 1, "score": 1, "title": "Directional lasing in resonant semiconductor nanoantenna arrays", "venue": "Nature Nanotechnology", "year": 2018 }, { "abstract": "Optical nanoantennas have shown a great capacity for efficient extraction of photons from the near to the far field, enabling directional emission from nanoscale single photon sources. However, their potential for the generation and extraction of multi photon quantum states remains unexplored. Here we experimentally demonstrate the nanoscale generation of two photon quantum states at telecommunication wavelengths based on spontaneous parametric down conversion in an optical nanoantenna. The antenna is a crystalline AlGaAs nanocylinder, possessing Mie type resonances at both the pump and the bi photon wavelengths, and when excited by a pump beam it generates photon pairs with a rate of 35 Hz. Normalized to the pump energy stored by the nanoantenna, this rate corresponds to 1.4 GHz/Wm, being 1 order of magnitude higher than conventional on chip or bulk photon pair sources. Our experiments open the way for multiplexing several antennas for coherent generation of multi photon quantum states with complex spatial mode entanglement and applications in free space quantum communications and sensing.", "author_names": [ "Giuseppe Marino", "Alexander S Solntsev", "Lei Xu", "Valerio Flavio Gili", "Luca Carletti", "Alexander N Poddubny", "Mohsen Rahmani", "Daria A Smirnova", "Haitao Chen", "Aristide Lemaitre", "Guoquan Zhang", "Anatoly V Zayats", "Costantino De Angelis", "Giuseppe Leo", "Andrey A Sukhorukov", "Dragomir N Neshev" ], "corpus_id": 209957319, "doc_id": "209957319", "n_citations": 35, "n_key_citations": 5, "score": 0, "title": "Spontaneous photon pair generation from a dielectric nanoantenna", "venue": "Optica", "year": 2019 }, { "abstract": "Dielectric photonics platform provides unique possibilities to control light scattering via utilizing high index dielectric nanoantennas with peculiar optical signatures. Despite the intensively growing field of all dielectric nanophotonics, it is still unclear how surrounding media affect scattering properties of a nanoantenna with complex multipole response. Here, we report on light scattering by a silicon cubic nanoparticle embedded in lossless media, supporting optical resonant response. We show that significant changes in the scattering process are governed by the electro magnetic multipole resonances, which experience spectral red shift and broadening over the whole visible and near infrared spectra as the indices of media increase. Most interestingly, the considered nanoantenna exhibits the broadband forward scattering in the visible and near infrared spectral ranges due to the Kerker effect in high index media. The revealed effect of broadband forward scattering is essential for highly demanding applications in which the influence of the media is crucial such as health care, e.g. sensing, treatment efficiency monitoring, and diagnostics. In addition, the insights from this study are expected to pave the way toward engineering the nanophotonic systems including but not limited to Huygens metasurfaces in media within a single framework.", "author_names": [ "Pavel D Terekhov", "Hadi K Shamkhi", "Egor A Gurvitz", "Kseniia V Baryshnikova", "Andrey B Evlyukhin", "Alexander S Shalin", "Alina Karabchevsky" ], "corpus_id": 119362133, "doc_id": "119362133", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Broadband forward scattering from dielectric cubic nanoantenna in lossless media.", "venue": "Optics express", "year": 2019 }, { "abstract": "Nonlinear plasmons are becoming an appealing and intriguing research area due to their remarkable light concentration and manipulation abilities. In this work, the nonlinear absorption (NLA) phenomena of polarized nanoantenna arrays coupled with the low dimensional topological insulator Bi2Se3 are studied at different excitation wavelengths. Our experimental results indicate that a significant enhancement in the linear absorption coefficient is achieved by localized surface plasmon (LSP) resonance, with enhancement factors that are 10 and 8 fold in magnitude for the cases of 800 nm (y polarization) and 970 nm (x polarization) respectively. Moreover, by polarization sensitive studies under 800 nm laser excitation, this new Bi2Se3 Au nanoantenna hybrid structure exhibits adverse absorption responses of enhancement and suppression compared to pure Bi2Se3 film, providing excellent potential for applications in information converters. In particular, under 800 nm pump light (10 GW cm 2) the transmittance intensity of 450 nm or 1064 nm continuous wave (CW) probe light alters back and forth when the polarization direction changes by 90deg. Thus, \"ON\" and \"OFF\" modes of this Bi2Se3 Au nanoantenna hybrid structure based switch are achieved by using 450 nm and 1064 nm light, respectively, with a corresponding modulation depth of 3.4% and 21.9% which can be applied in versatile photonic devices.", "author_names": [ "Runlin Miao", "Yuze Hu", "Hao Ouyang", "Yuxiang Tang", "Chenxi Zhang", "Jie You", "Xin Zheng", "Zhongjie Xu", "Xiang'ai Cheng", "Tian Jiang" ], "corpus_id": 196617572, "doc_id": "196617572", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "A polarized nonlinear optical response in a topological insulator Bi2Se3 Au nanoantenna hybrid structure for all optical switching.", "venue": "Nanoscale", "year": 2019 }, { "abstract": "Formation of dressed light matter states in optical structures, manifested as Rabi splitting of the eigen energies of a coupled system, is one of the key effects in quantum optics. In pursuing this regime with semiconductors, light is usually made to interact with excitons, electrically neutral quasiparticles of semiconductors; meanwhile interactions with charged three particle states, trions, have received little attention. Here, we report on strong interaction between localized surface plasmons in silver nanoprisms and excitons and trions in monolayer tungsten disulfide (WS2) We show that the plasmon exciton interactions in this system can be efficiently tuned by controlling the charged versus neutral exciton contribution to the coupling process. In particular, we show that a stable trion state emerges and couples efficiently to the plasmon resonance at low temperature by forming three bright intermixed plasmon exciton trion polariton states. Our findings open up a possibility to exploit electrically charged polaritons at the single nanoparticle level.", "author_names": [ "Jorge Cuadra", "Denis G Baranov", "Martin Wersall", "Ruggero Verre", "Tomasz J Antosiewicz", "Timur O Shegai" ], "corpus_id": 206746067, "doc_id": "206746067", "n_citations": 101, "n_key_citations": 0, "score": 0, "title": "Observation of Tunable Charged Exciton Polaritons in Hybrid Monolayer WS2 Plasmonic Nanoantenna System.", "venue": "Nano letters", "year": 2018 }, { "abstract": "In the context of using portions of a photosynthetic apparatus of green plants and photosynthesizing bacteria in bioinspired photovoltaic systems, we consider possible control of the chlorophyll excited state decay rate using nanoantennas in the form of a single metal and semiconductor nanoparticle. Since chlorophyll luminescence competes with electron delivery for chemical reactions chain and also to an external circuit, we examine possible excited state decay inhibition contrary to radiative rate enhancement. Both metal and semiconductor nanoparticles enable inhibition of radiative decay rate by one order of the magnitude as compared to that in vacuum, whereas a metal nanosphere cannot perform the overall decay inhibition since slowing down of radiative decay occurs only along with the similar growth of its nonradiative counterpart whereas a semiconductor nanoantenna is lossless. Additionally, at normal orientation of the emitter dipole moment to a nanoparticle surface, a silicon nanoparticle promotes enhancement of radiative decay by one order of the magnitude within the whole visible range. Our results can be used for other photochemical or photovoltaic processes, and strong radiative decay enhancement found for dielectric nanoantennas paves the way to radiative decays and light emitters engineering without non radiative losses.", "author_names": [ "Sergey V Gaponenko", "Pierre-Michel Adam", "Dmitry V Guzatov", "Alina Muravitskaya" ], "corpus_id": 148573402, "doc_id": "148573402", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Possible nanoantenna control of chlorophyll dynamics for bioinspired photovoltaics", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "Abstract Owing to unique electronic and plasmonic properties at terahertz (THz) band, two dimensional nano material graphene make it easy for the design of highly miniaturized ultra wideband (UWB) reconfigurable THz antenna with simple nano structure at subwavelength scale. In this paper, a sub wavelength miniaturized UWB reconfigurable graphene circular patch nanoantenna at THz band is reported. The simple structured graphene circular patch nanoantenna provides ultra wideband of impedance bandwidth of 370% The propagation of SPP waves in graphene THz antenna enables high miniaturization at THz band. At resonant frequency 0.75 THz, SPP wavelength lSPP of the antenna is 10 times smaller than free space wavelength l0. Broad side radiation pattern with lower back lobe radiation is found at resonant frequency of the antenna. Moreover, frequency reconfiguration in the antenna is easily achievable by applying external voltage via Fermi energy of graphene. For a comparison propose, copper circular patch nanoantenna of the same dimension has been modelled in this work. Copper circular patch nanoantenna resonates at higher frequency 1.15 THz and provides a very narrow bandwidth. Compared to conventional copper metal antenna, graphene nanoantenna enables high miniaturization, UWB behavior, and easy reconfiguration. The proposed graphene nanoantenna can be promising for UWB THz applications.", "author_names": [ "Sasmita Dash", "Amalendu Patnaik" ], "corpus_id": 202979091, "doc_id": "202979091", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Sub wavelength Graphene Planar nanoantenna for THz Application", "venue": "", "year": 2019 }, { "abstract": "Strong coupling of an intersubband (ISB) electron transition in quantum wells to a subwavelength plasmonic nanoantenna can give rise to intriguing quantum phenomena, such as ISB polariton condensation, and enable practical devices including low threshold lasers. However, experimental observation of ISB polaritons in an isolated subwavelength system has not yet been reported. Here, we use scanning probe near field microscopy and Fourier transform infrared (FTIR) spectroscopy to detect formation of ISB polariton states in a single nanoantenna. We excite the nanoantenna by a broadband IR pulse and spectrally analyze evanescent fields on the nanoantenna surface. We observe the distinctive splitting of the nanoantenna resonance peak into two polariton modes and two p phase steps corresponding to each of the modes. We map ISB polariton dispersion using a set of nanoantennae of different sizes. This nano FTIR spectroscopy approach opens doors for investigations of ISB polariton physics in the single subwavelength nanoantenna regime.", "author_names": [ "Chih-Feng Wang", "Terefe G Habteyes", "Ting S Luk", "John F Klem", "Igal Brener", "Hou-Tong Chen", "Oleg Mitrofanov" ], "corpus_id": 184486150, "doc_id": "184486150", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Observation of Intersubband Polaritons in a Single Nanoantenna Using Nano FTIR Spectroscopy.", "venue": "Nano letters", "year": 2019 }, { "abstract": "We study light emission from square arrays of Mie resonant silicon nanoantennas situated on a fluorescent glass substrate. When the spectral positions of the silicon nanoantennas' resonances overlap with the intrinsic emission from the glass, the emission is selectively enhanced for certain spectral and spatial frequencies detemined by the design of the nanoantenna array. We measure the emission spectra of the coupled system for a systematic variation of the nanoantenna geometry, showing that the spectral maximum of the emission coincides with the antenna resonance positions observed in linear optical transmittance spectra. Furthermore, we study the directionality of the emission by back focal plane imaging and numerical calculations based on the Fourier modal method and the reciprocity principle. We observe that the nanoantenna array induces a reshaping of the resonantly enhanced emission in the air half space into a narrow lobe directed out of the substrate plane. This reshaping is explained by coherent.", "author_names": [ "Aleksandr Vaskin", "Justus Bohn", "Katie E Chong", "Tobias Bucher", "Matthias Zilk", "Duk-Yong Choi", "Dragomir N Neshev", "Yuri S Kivshar", "Thomas Pertsch", "Isabelle Staude" ], "corpus_id": 126363324, "doc_id": "126363324", "n_citations": 62, "n_key_citations": 0, "score": 0, "title": "Directional and Spectral Shaping of Light Emission with Mie Resonant Silicon Nanoantenna Arrays", "venue": "", "year": 2018 }, { "abstract": "High refractive index (HRI) nanostructures support optically induced electric dipole (ED) and magnetic dipole (MD) modes that can be used to control scattering and achieve narrowband absorption. In this work, a high absorptance device is proposed and realized by using amorphous silicon nanoantenna (a Si NA) arrays that suppress backward and forward scattering with engineered structures and in particular periods. The overlap of ED and MD resonances, by designing an array with a specific period and exciting lattice resonances, is experimentally demonstrated. The absorptance of a Si NA arrays increases 3 fold in the near infrared range in comparison to unpatterned silicon films. Nonradiating a Si NA arrays can achieve high absorptance with a small resonance bandwidth (Q 11.89) at a wavelength of 785 nm. The effect is observed not only due to the intrinsic loss of material but by overlapping the ED and MD resonances.", "author_names": [ "Chi-Yin Yang", "Jhen-Hong Yang", "Zih-Ying Yang", "Zhong-Xing Zhou", "Mao-Guo Sun", "Viktoriia E Babicheva", "Kuo-Ping Chen" ], "corpus_id": 125160897, "doc_id": "125160897", "n_citations": 54, "n_key_citations": 0, "score": 0, "title": "Nonradiating Silicon Nanoantenna Metasurfaces as Narrowband Absorbers", "venue": "", "year": 2018 } ]

[ { "abstract": "Abstract Applications of the wide band gap (WBG) semiconductors, such as GaN, AlGaN, and InGaN, range from lighting and ultraviolet (UV) technology to high power, radiation hard, high temperature, terahertz (THz) and sub THz electronics and pyroelectronics. Wurtzite (hexagonal) symmetry makes these materials to be quite different from conventional cubic semiconductors. Spontaneous and piezoelectric polarization associated with the wurtzite crystal structure induces two dimensional electron gases at AlGaN/GaN, AlInN/GaN, and AlGaN/InGaN interfaces with sheet concentrations 10 20 times higher than those in Si CMOS. A high current carrying capability and a high breakdown field make these materials perfect for high power applications. Adjusting the energy gaps of AlxGa1 xN and of InxGa1 xN by varying the molar fraction changes the wavelength of light they emit or absorb and enables light and UV emitters, solar cells, and photodetectors operating from THz and infrared to deep UV range. Blue, green, and white LEDs using InGaN revolutionized smart solid state lighting. AlGaN UV LEDs are used for water purification, fighting antibiotic resistant bacteria and viruses, and dramatically increasing produce storage time. InN, ZnO, and BN have potential to compete with the AlN/GaN family. Diamond has re emerged not only as a substrate for a record heat removal but also as a viable THz detector material. The WBG technology has many difficult problems to solve. High dislocation density in the WBG materials leads to a low efficiency of deep AlGaN UV LEDs and reliability problems of high power devices. Non uniformities of the electric field distribution cause a premature breakdown. Using ultrathin WBG quantum well layers and nanowires and exploring radically new physics based device designs might alleviate or even solve these problems.", "author_names": [ "Michael S Shur" ], "corpus_id": 107644023, "doc_id": "107644023", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Wide band gap semiconductor technology: State of the art", "venue": "Solid State Electronics", "year": 2019 }, { "abstract": "The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today's transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore's law. This article presents a review of new architectures, simulation methods, and process technology for nano scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future.", "author_names": [ "Henry H Radamson", "Huilong Zhu", "Zhenhua Wu", "Xiaobin He", "Hongxiao Lin", "Jinbiao Liu", "Jinjuan Xiang", "Zhenzhen Kong", "Wenjuan Xiong", "Junjie Li", "Hushan Cui", "Jian-feng Gao", "Hong Yang", "Yong Du", "Buqing Xu", "Ben Li", "Xuewei Zhao", "Jiahan Yu", "Yan Dong", "Guilei Wang" ], "corpus_id": 221126630, "doc_id": "221126630", "n_citations": 29, "n_key_citations": 0, "score": 1, "title": "State of the Art and Future Perspectives in Advanced CMOS Technology", "venue": "Nanomaterials", "year": 2020 }, { "abstract": "The power density limits of complementary metal oxide semiconductor (CMOS) technology could be overcome by moving from a binary to a ternary logic system. However, ternary devices are typically based on multi threshold voltage schemes, which make the development of power scalable and mass producible ternary device platforms challenging. Here we report a wafer scale and energy efficient ternary CMOS technology. Our approach is based on a single threshold voltage and relies on a third voltage state created using an off state constant current that originates from quantum mechanical band to band tunnelling. This constant current can be scaled down to a sub picoampere level under a low applied voltage of 0.5 V. Analysis of a ternary CMOS inverter illustrates the variation tolerance of the third intermediate output voltage state, and its symmetric in out voltage transfer characteristics allow integrated circuits with ternary logic and memory latch cell functions to be demonstrated. Quantum mechanical band to band tunnelling can be used to create an energy efficient ternary logic technology that can be fabricated on the wafer scale using complementary metal oxide semiconductor (CMOS) processes.", "author_names": [ "Jae Won Jeong", "Young Eun Choi", "Woo Seok Kim", "Jee-Ho Park", "Sunmean Kim", "Sunhae Shin", "Kyuho Lee", "Jiwon Chang", "Seong-Jin Kim", "Kyung Rok Kim" ], "corpus_id": 199187261, "doc_id": "199187261", "n_citations": 22, "n_key_citations": 2, "score": 0, "title": "Tunnelling based ternary metal oxide semiconductor technology", "venue": "Nature Electronics", "year": 2019 }, { "abstract": "This paper presents a systematized review of the research on the production of nanosecond high power pulses using solid state generators based on an inductive energy store and a semiconductor opening switch that have been performed in the past 25 years. This research has been underway since 1992 1993 when the nanosecond cutoff of ultrahigh density currents in semiconductor diodes was discovered and named the SOS (Semiconductor Opening Switch) effect. The discovery of the SOS effect provided a breakthrough in the development of semiconductor generators, as their most important characteristics, such as pulse power and output voltage, were increased tens and hundreds of times compared with previously known semiconductor generators. In particular, in the nanosecond semiconductor technology, megavolt voltages combined with gigawatt peak powers have been achieved. This review considers the main physical processes that determine the mechanism of operation of a SOS based on the SOS effect. The principle of operation, design, and characteristics of SOS diodes and SOS generators is described, and prospects for their further development are discussed. Examples are given of using SOS generators in various pulsed power applications such as electron accelerators, X ray pulse devices, high power microwave electronics, pumping of gas lasers, and ignition of electrical discharges.", "author_names": [ "Sergei N Rukin" ], "corpus_id": 211023605, "doc_id": "211023605", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Pulsed power technology based on semiconductor opening switches: A review.", "venue": "The Review of scientific instruments", "year": 2020 }, { "abstract": "A new time domain wideband numerical model for simulation of quantum dot reflective semiconductor optical amplifier (QD RSOA) steady state and dynamic behavior, is described. The model is used to investigate 1 ps full width at half maximum input Gaussian pulse amplification and also modulation cancellation. A large modulation cancellation dynamic range of about 35 dB, is predicted for high input powers, which is not attainable in bulk and QW RSOAs. The model can be applied to traveling wave and reflective QD SOAs. The combination of the unique features of quantum dots and a reflective structure can be used to realize a colorless modulator for wavelength division multiplexed passive optical networks (WDM PONs)", "author_names": [ "Khalil Safari Anzabi", "Amir Habibzadeh-Sharif", "Michael J Connelly", "Ali Rostami" ], "corpus_id": 209985489, "doc_id": "209985489", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Wideband Steady State and Pulse Propagation Modeling of a Reflective Quantum Dot Semiconductor Optical Amplifier", "venue": "Journal of Lightwave Technology", "year": 2020 }, { "abstract": "The International Technology Roadmap for Semiconductors (ITRS) has roadmapped technology requirements of the semiconductor industry over the past two decades. The roadmap identifies major challenges in advanced technology and leads the investment of research in a cost effective way. Traditionally, the ITRS identifies major semiconductor IC products as drivers; these set requirements for the state of the art semiconductor technologies. High performance microprocessor unit (MPU HP) for servers and consumer portable system on chip (SOC CP) for smartphones are two examples. Throughout the history of the ITRS, Moore's Law has been the main impetus for these drivers, continuously pushing the transistor density to scale at a rate of 2x per technology generation (aka \"node\" However, as new requirements from applications such as data center, mobility, and context aware computing emerge, the existing roadmapping methodology is unable to capture the entire evolution of the current semiconductor industry. Today, comprehending how key markets and applications drive the process, design and integration technology roadmap requires new system level studies along with chip level studies. In this paper, we extend the current ITRS roadmapping process with studies of key requirements from a system level perspective, based on multiple generations of smartphones and microservers. We describe potential new system drivers and new metrics, and we refer to the new system level framing of the roadmap as ITRS 2.0.", "author_names": [ "Juan Antonio Carballo", "Wei-Ting Jonas Chan", "Paolo A Gargini", "Andrew B Kahng", "Siddhartha Nath" ], "corpus_id": 3221445, "doc_id": "3221445", "n_citations": 65, "n_key_citations": 3, "score": 0, "title": "ITRS 2.0: Toward a re framing of the Semiconductor Technology Roadmap", "venue": "2014 IEEE 32nd International Conference on Computer Design (ICCD)", "year": 2014 }, { "abstract": "The Planar Technology. Solid State Technology. Vapor Phase Growth. Thermal Oxidation. Solid State Diffusion. Semiconductors and Semiconductor Devices. Elements of Semiconductor Physics. Semiconductors under Non Equilibrium Conditions. p n Junction. Junction Transistor. Junction Field Effect Transistors. Surface Effects and Surface Controlled Devices. Theory of Semiconductor Surfaces. Surface Effects on p n Junctions. Surface Field Effect Transistors. Properties of the Silicon Silicon Dioxide System.", "author_names": [ "Andrew S Grove" ], "corpus_id": 108892408, "doc_id": "108892408", "n_citations": 2260, "n_key_citations": 51, "score": 0, "title": "Physics and Technology of Semiconductor Devices", "venue": "", "year": 1967 }, { "abstract": "This volume is a collection of papers presented at the 10th International Autumn Meeting on \"Gettering and Defect Engineering in Semiconductor Technology GADEST 2003\" which took place from the 21st to the 26th of September 2003 at the Seehotel Zeuthen, in the state of Brandenburg, Germany. It provided a forum for interactions between scientists and engineers engaged in the field of semiconductor defect physics, materials science and technology, to reflect upon aspects of the coming era of conversion from micro electronics to nano electronics. In addition, a particular ambition was to strengthen the interactions and exchanges between communities working in the fields of crystalline silicon for electronics and photovoltaics.", "author_names": [ "H W Richter", "Martin Kittler" ], "corpus_id": 106678625, "doc_id": "106678625", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Gettering and defect engineering in semiconductor technology GADEST 2003 proceedings of the 10th International Autumn Meeting, Seehotel Zeuthen (suburb of Berlin) State of Brandenburg, Germany, September 21 26, 2003", "venue": "", "year": 2004 }, { "abstract": "Abstract The electrical detection of DNA methylation based biomarkers using semiconductor technology shows great promise for early cancer screening. Presented is the very first proof of concept example of using CMOS based technology for real time DNA methylation detection using Ion Sensitive Field Effect Transistors (ISFETs) An electrochemical label free approach was applied in two gene assays, each one of which incorporated the sequences of DAPK 1 and CDKN 2 A p 16 INK 4 p 16) gene promoters at a both methylated and unmethylated state, performing isothermal methylation specific amplification and detection both in tube and on chip (real time) Good discrimination was shown between the two states, achieving a very good average pH signal change for the methylated state of 1.91 for DAPK 1 assay and of 1.58 for p 16 assay in the tube test. The real time on chip test showed similarly good real time differential signal change in favour of methylated DNA, reaching 37 mV for DAPK 1 assay and 23 mV for p 16 assay, validating the results from the proof of concept test of pH LAMP in tube while confirming the sensitivity of real time methylation specific pH LAMP on chip.", "author_names": [ "Melpomeni Kalofonou", "Christofer Toumazou" ], "corpus_id": 93830973, "doc_id": "93830973", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Semiconductor technology for early detection of DNA methylation for cancer: From concept to practice", "venue": "", "year": 2013 }, { "abstract": "An outstanding goal in quantum optics and scalable photonic quantum technology is to develop a source that each time emits one and only one entangled photon pair with simultaneously high entanglement fidelity, extraction efficiency, and photon indistinguishability. By coherent two photon excitation of a single InGaAs quantum dot coupled to a circular Bragg grating bull's eye cavity with a broadband high Purcell factor of up to 11.3, we generate entangled photon pairs with a state fidelity of 0.90(1) pair generation rate of 0.59(1) pair extraction efficiency of 0.62(6) and photon indistinguishability of 0.90(1) simultaneously. Our work will open up many applications in high efficiency multiphoton experiments and solid state quantum repeaters.", "author_names": [ "Hui Wang", "Hai Hu", "T H Chung", "Jian Qin", "Xiaoxia Yang", "J-P Li", "R-Z Liu", "Han-Sen Zhong", "Y -M He", "Xing Ding", "Y -H Deng", "Qing Dai", "Yongheng Huo", "Sven Hofling", "Chao-Yang Lu", "Jian-Wei Pan" ], "corpus_id": 84836268, "doc_id": "84836268", "n_citations": 109, "n_key_citations": 2, "score": 0, "title": "On Demand Semiconductor Source of Entangled Photons Which Simultaneously Has High Fidelity, Efficiency, and Indistinguishability.", "venue": "Physical review letters", "year": 2019 } ]

[ { "abstract": "Abstract Condition based maintenance and the prediction of the remaining useful life (RUL) of cutting tools are of crucial importance to reduce unexpected downtime and ensure quality. Our paper proposes an original RUL prediction model based on health index (HI) similarity, where both distance similarity and spatial direction similarity are considered. Data mining is carried out to the large and messy original monitoring data to construct the HIs of the cutting tools, which are then used to predict the RUL. The novelty of our method is that it can make full use of limited historical datasets to achieve more accurate prediction results. The model is applied to the data obtained from a turbine factory's slotting cutter machining process and is compared to one of the most popular prognostic method least squares support vector regression. Our proposed approach is also applied to two further case studies a GaAs based semiconductor laser and simulated data. The comparative results show the effectiveness and practicability of our proposed method, even when the data fluctuate a lot and show distinctive trends.", "author_names": [ "Yingchao Liu", "Xiaofeng Hu", "Wenjuan Zhang" ], "corpus_id": 115527725, "doc_id": "115527725", "n_citations": 33, "n_key_citations": 1, "score": 1, "title": "Remaining useful life prediction based on health index similarity", "venue": "Reliab. Eng. Syst. Saf.", "year": 2019 }, { "abstract": "T/R module is an important part of large phased array radar antenna array, the remaining useful life (RUL) prediction is of great significance for equipment support personnel to master current health status and improve maintenance support ability. At first, the key indexes of multistate degradation are extracted by association rule, by calculating the similarity of the key indexes and combining the RUL of similar samples, the RUL information corresponding to the key indexes is obtained. The RUL prediction results of T/R module are obtained according to the weight of different indexes. The practicability and effectiveness of the proposed method are verified by example analysis and comparison, which provide theoretical guidance for the RUL prediction of electronic equipment. The proposed method is of great significance for maintenance support personnel of the military equipment to plan the maintenance resources reasonably and improve the combat effectiveness of the equipment.", "author_names": [ "Xiaodong Hou", "Jiangping Yang", "Bin Deng", "Chunhe Chang", "Yu Lin Zhang", "Jiajing Xu" ], "corpus_id": 57756831, "doc_id": "57756831", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Remaining Useful Life Prediction Method for T/R Module Based on Index Similarity", "venue": "2018 Prognostics and System Health Management Conference (PHM Chongqing)", "year": 2018 }, { "abstract": "The concept of Prognostic and Health Management (PHM) on machinery attracts a lot of attention during these years, as a key technique of PHM, the prediction of Remaining Useful Life (RUL) of equipment is well studied. As a method with reasonable assumption, Health Index (HI) is successfully applied in RUL prediction. However, in the scenario of large mechanical equipment, there are some disadvantages in tradition HI method. So the notion of Core State is raised and some improvements are introduced, and furthermore, a unified framework for the RUL prediction of large equipment, which mainly based on similarity metric of HI, is then presented. Finally, the proposed idea was carried out through a real data experiment. The result indicated the signification effect of Core State in RUL prediction and verified the validity of the framework as well.", "author_names": [ "Bo Wang", "Li Zhang", "Xuliang He" ], "corpus_id": 17971039, "doc_id": "17971039", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Study on the prediction of Remaining Useful Life of large equipment based on the similarity metric of Health Index", "venue": "2010 International Conference on Mechanic Automation and Control Engineering", "year": 2010 }, { "abstract": "Predicting the remaining useful life (RUL) of systems is of importance in prognostics and health management to improve the maintenance capability in modern industries. Several approaches for RUL prediction using multiple sensory data assume the system's degradation in a specific form, which may not be applicable to the diversity of practical engineering systems. In this paper, a two phase data driven framework is proposed. The first phase is an offline process of constructing the health index (HI) library from run to failure data using fuzzy similarity based data fusion, which enables to create the HIs without any assumptions. In the second phase, the HI of online is mapped onto the library created offline to find the best matching position using time series similarity search. This simultaneously enables the current condition of the system being informed as well as estimating its time left. The degradation simulation dataset of turbofan engine from NASA Prognostics Center is used to evaluate the potential application of the proposed framework.", "author_names": [ "Van Tung Tran", "Jihoon Hong" ], "corpus_id": 227062276, "doc_id": "227062276", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Multi Sensor Prognostics Framework Based on Data Fusion and Time Series Similarity Search", "venue": "IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society", "year": 2020 }, { "abstract": "Abstract Remaining useful life (RUL) estimation of a degrading system is the major prognostic activity in many industry applications. This paper presents an improved version of the similarity based curve matching method for the remaining useful life estimation of a mechanical system, which is a companion paper of our previous work on RUL estimations using a bidirectional recurrent neural network (RNN) based autoencoder scheme. We propose a zero centering rule to tackle the varying initial health across instances (systems) when using the similarity based health index curve matching technique to identify the training instances that share a similar degradation pattern with the test instance whose RUL needs to be determined. However, this rule will also induce a significant prediction error, especially when the off line training instances are abundant, or the true RULs of the on line test instances are large. Thus, an ensemble approach that integrates the RUL estimations obtained from the similarity based curve matching techniques, with and without the zero centering rules, is introduced to increase the robustness and accuracy of proposed method for RUL estimations. We evaluate the prognostic performance of the ensemble algorithm and standalone algorithms on four publicly available turbofan engine degradation datasets. The results demonstrate that the proposed ensemble approach gives more robust and reliable RUL estimations compared to any independent algorithm used on all the studied datasets.", "author_names": [ "W Yu", "Ii Yong Kim", "Chris K Mechefske" ], "corpus_id": 216460930, "doc_id": "216460930", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "An improved similarity based prognostic algorithm for RUL estimation using an RNN autoencoder scheme", "venue": "Reliab. Eng. Syst. Saf.", "year": 2020 }, { "abstract": "Abstract Remaining useful life (RUL) prediction has been a difficult problem in industry and academia. Deep learning techniques based on supervised learning have made great progress compared to traditional prediction algorithms. However, due to the random nature of system degradation behavior, deep supervised learning cannot accurately adapt the model obtained based on the training set to the systems in the testing set. The similarity based prediction method has achieved accurate approximate remaining life, which called similar RUL. Therefore, the combination of supervised learning and similarity based prediction has the potential to take advantages of the learning ability of the network model and similar RUL to improve the prediction accuracy. This paper investigates the effect of using similarity to improve the prediction accuracy of deep supervised learning. In addition, since health indicator (HI) and target labels are the essential factors of supervised learning, this paper proposes a method for constructing HI based on unsupervised learning. Then according to the constructed HI, a difference based method proposed to generate target labels. To verify the effectiveness of the proposed method, this paper conducted experimental verification on the C MAPSS engine dataset and XJTU SY bearing dataset and made related comparative experiments. Experimental results show that the proposed method obtains favorable results against the traditional methods.", "author_names": [ "Mengru Hou", "Dechang Pi" ], "corpus_id": 216405347, "doc_id": "216405347", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Similarity based deep learning approach for remaining useful life prediction", "venue": "", "year": 2020 }, { "abstract": "In view of the problems of degradation index construction and predicted lag of similarity based methods, a degradation degree considered method for remaining useful life prediction based on similarity is proposed. The effectiveness of the proposed method is demonstrated by using turbofan engine data from NASA and a real case study.", "author_names": [ "Zeming Liang", "Jianmin Gao", "Hong-Quan Jiang", "Xu Gao", "Zhiyong Gao", "Rongxi Wang" ], "corpus_id": 71151871, "doc_id": "71151871", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "A Degradation Degree Considered Method for Remaining Useful Life Prediction Based on Similarity", "venue": "Computing in Science Engineering", "year": 2019 }, { "abstract": "Extracting suitable features from acquired data to accurately depict the current health state of a system is crucial in data driven condition monitoring and prediction. Usually, analogue sensor data is sampled at rates far exceeding the Nyquist rate containing substantial amounts of redundancies and noise, imposing high computational loads due to the subsequent and necessary feature processing chain (generation, dimensionality reduction, rating and selection) To overcome these problems, Compressed Sensing can be used to sample directly to a compressed space, provided the signal at hand and the employed compression/measurement system meet certain criteria. Theory states, that during this compression step enough information is conserved, such that a reconstruction of the original signal is possible with high probability. The proposed approach however does not rely on reconstructed data for condition monitoring purposes, but uses directly the compressed signal representation as feature vector. It is hence assumed that enough information is conveyed by the compression for condition monitoring purposes. To fuse the compressed coefficients into one health index that can be used as input for remaining useful life prediction algorithms and is limited to a reasonable range between 1 and 0, a logistic regression approach is used. Run to failure data of three translational electromagnetic actuators is used to demonstrate the health index generation procedure. A comparison to the time domain ground truth signals obtained from Nyquist sampled coil current measurements shows reasonable agreement. I.e. underlying wear out phenomena can be reproduced by the proposed approach enabling further investigation of the application of prognostic methods.", "author_names": [ "Christian Knoebel", "Daniel Strommenger", "Johannes Reuter", "Clemens Guehmann" ], "corpus_id": 204101942, "doc_id": "204101942", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Health Index Generation Based on Compressed Sensing and Logistic Regression for Remaining Useful Life Prediction", "venue": "Annual Conference of the PHM Society", "year": 2019 }, { "abstract": "In this work, a hybrid prognostic framework which interfaces a model based prognostic method, namely particle filter, with a similarity based prognostic method is proposed. The proposed framework consists of automatic determination of predication start point, sensor fusion, and prognostics steps that lead to accurate remaining useful life (RUL) estimations. This approach first applies the canonical variate analysis (CVA) approach for determining the prediction start time and constructing the prognostic health indicators (HIs) The similarity based method is then employed together with the model based particle filter (PF) algorithm to improve the predictive performance in terms of reducing the uncertainty of RUL and improving the prediction accuracy. The proposed framework can automatically construct HIs that are suitable for RUL prediction and offer higher prediction accuracy and lower uncertainty boundaries than traditional model based PF methods. Our proposed approach is successfully applied on aircraft turbofan engines RUL prediction.", "author_names": [ "Xiaochuan Li", "David Mba", "Tianran Lin" ], "corpus_id": 209496960, "doc_id": "209496960", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Similarity based and Model based Fusion Prognostics Framework for Remaining Useful Life Prediction", "venue": "2019 Prognostics and System Health Management Conference (PHM Qingdao)", "year": 2019 }, { "abstract": "The problems in the remaining useful life (RUL) prediction of rolling bearings are difficulty in determining the failure threshold and large prediction error with a single prediction model. To solve them, based on the adaptive boosting integrated relevance vector machine model (AdaBoost_RVM) a method for constructing health indices and predicting RUL is proposed. The experimental results show that the failure thresholds of all the different bearings are 1 using the proposed method, and compared with the single RVM model, it yields a bearing RUL prediction that has a smaller error and is closer to the true value.", "author_names": [ "Wang Yujing", "Wang Shida", "Kang Shou-qiang", "Xie Jinbao" ], "corpus_id": 218908205, "doc_id": "218908205", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Health index construction and remaining useful life prediction of rolling bearings", "venue": "2019 14th IEEE International Conference on Electronic Measurement Instruments (ICEMI)", "year": 2019 } ]

[ { "abstract": "Experimental results concerning the study of phase noise in single mode semiconductor lasers are reported, which show a strict connection between phase and intensity noise. In particular, phase noise spectrum is found to present a sharp peak at the same peak frequency of intensity noise spectrum, a fact which is proven to be responsible for the appearance of satellite peaks in the emission line shape. Direct measurements of the line shape, performed by means of a Fabry Perot interferometer, are in agreement with the line shape evaluated by using phase noise spectrum measurements.", "author_names": [ "Benedetto Daino", "Paolo Spano", "Mario Tamburrini", "Sabino Piazzolla" ], "corpus_id": 120471829, "doc_id": "120471829", "n_citations": 136, "n_key_citations": 0, "score": 1, "title": "Phase noise and spectral line shape in semiconductor lasers", "venue": "", "year": 1983 }, { "abstract": "In this paper, we present a full analysis of noise in semiconductor lasers. Time covariance and cross covariance functions of all variables governing single mode semiconductor laser behavior are given including all Langevin noise sources and considering all terms of the laser rate equations, RIN, carrier noise spectrum, frequency noise spectrum, coherence between the FM and AM noise, variance of the phase change and coupling between amplitude and phase are investigated analytically in their more general form. Spectral line shape has been derived showing dissymmetrical satellite lines centered at multiple integers of relaxation frequency around a central line. It is shown that neglecting the shot noise and considering only the carrier contribution in phase dynamics (common procedure) are too general approximations.", "author_names": [ "Lotfi Hassine", "Zeno Toffano", "Francoise Lamnabhi-Lagarrigue", "Alain Destrez", "Irene Joindot" ], "corpus_id": 121901723, "doc_id": "121901723", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Volterra functional series expansions for noise in semiconductor lasers", "venue": "", "year": 1994 }, { "abstract": "This paper considers the effect of phase conjugate feedback (PCF) on the noise characteristics of semiconductor lasers. By using the single mode, rate equation formalism, it is shown that semiconductor lasers can achieve a steady state as long as the amount of PCF is below a critical value. For an ideal phase conjugate mirror, the average value of the steady state phase of the semiconductor laser is found to be locked to a fixed value, determined by the linewidth enhancement factor of the laser. The noise characteristics in the presence of PCF are studied by adding the Langevin noise terms representing the effect of spontaneous emission to the rate equations and solving them approximately. Both the intensity noise and the frequency noise are reduced at low frequencies (below 100 MHz) In particular, the frequency noise nearly vanishes at zero frequency because of the phase locked nature of the steady state solution. The spectral line shape does not remain Lorentzian in the presence of PCF. The satellite peaks occurring at the relaxation oscillation frequency are considerably enhanced because of a reduction in the damping rate of such oscillations.", "author_names": [ "" ], "corpus_id": 33937097, "doc_id": "33937097", "n_citations": 54, "n_key_citations": 3, "score": 0, "title": "Effect of phase conjugate feedback on the noise characteristics of semiconductor lasers.", "venue": "Physical review. A, Atomic, molecular, and optical physics", "year": 1992 }, { "abstract": "Continuous phase frequency shift keying (CPFSK) is a promising technique for optical communication systems using either coherent or direct detection since it utilizes direct modulation of the semiconductor lasers [1 4] More importantly, the CPFSK signal features a compact spectrum which is necessary for the implementation of an optical frequency division multiplexing (FDM) network [1 2] Knowledge of the spectral density for optical CPFSK signals corrupted by laser phase noise is essential for the design and analysis of CPFSKbased systems, for example, the crosstalk analysis for optical FDM systems using coherent detection [1] or direct detection [2] the analysis of nonlinear effects [3] and the receiver filter design [4] The spectrum was previously obtained by means of numerical convolution of the CPFSK spectrum without phase noise and the laser spectrum with Lorentzian line shape [1 3] In this paper, closed analytical expressions are derived for the power spectral density of optical CPFSK signals with an arbitrary laser linewidth. They are useful for the design and analysis of optical communication systems using CPFSK modulation. where RF(t) is the autocorrelation function of the CPFSK signal without phase noise. Dn is the laser full width half maximum (FWHM) linewidth (without CPFSK modulation) A Lorentzian laser line shape is assumed.", "author_names": [ "Q Jiang", "Mohsen Kavehrad" ], "corpus_id": 112613844, "doc_id": "112613844", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spectral Density Function of Optical CPFSK Signals in the Presence of Laser Phase Noise", "venue": "", "year": 1994 }, { "abstract": "We consider the performance of quadratically detected heterodyned lightwave signals in the presence of a laser's relaxation oscillations. Here the limiting form of the channel presents both additive white Gaussian noise (AWGN) of spectral density N/sub 0/ and the laser's phase noise. The widely accepted model for the laser's phase noise is a Brownian motion giving rise to a Lorentzian line spectrum. However, the actual line shape of semiconductor lasers deviates from this simplified and idealized statistical characterization. The analytical techniques provided here show that this deviation may have a significant impact on the communication system performance.", "author_names": [ "Yeheskel E Dallal", "Gunnar Jacobsen", "Shlomo Shamai" ], "corpus_id": 61142022, "doc_id": "61142022", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "On the impact of laser's relaxation oscillation on quadratically detected heterodyned lightwave signals", "venue": "Proceedings of 1995 IEEE International Symposium on Information Theory", "year": 1995 }, { "abstract": "This article reports on extensive investigations of the influence of external optical feedback (OFB) on the spectral line shape and the associated spectra of relative intensity noise (RIN) and frequency noise (FN) in semiconductor lasers. The study is based on a generalized simulation model that treats the OFB as a multiple roundtrip time delay of the lasing field in the external cavity. We present criteria to apply the famous Lang Kobayashi model to predict the operation characteristics of lasers under OFB. The accuracy of approximated models of calculating the spectral linewidth from the low frequency components of the frequency noise is examined. We characterize the spectral line shape and the spectra of the RIN and FN in five distinct operating regions, namely, continuous wave (cw) weak OFB induced pulsation, period doubling route to chaos, chaos or coherence collapse, and strong OFB induced pulsation. InGaAsP lasers emitting in a wavelength of 1.5 mm are included in the calculations. The results sho.", "author_names": [ "Moustafa Ahmed", "Minoru Yamada" ], "corpus_id": 120437976, "doc_id": "120437976", "n_citations": 41, "n_key_citations": 2, "score": 0, "title": "Field fluctuations and spectral line shape in semiconductor lasers subjected to optical feedback", "venue": "", "year": 2004 }, { "abstract": "Beating between the lasing main mode and the non lasing side modes is one of the intensity noise sources of single longitudinal mode lasers. Its characteristics were investigated experimentally recent years. This paper presents a theoretical study of mode beating noises in semiconductor lasers, and intends to explain the experimentally observed phenomena. The effects of coherent population oscillation (CPO) induced by mode beating on gain coefficient and on reflective index are analyzed based on Maxwell Bloch equation and rate equations. The power ratio of the side mode over its conjugation mode generated by four wave mixing (FWM) is discussed; formulas of amplitude and frequency of mode beating intensity noise are given with relations to pump levels and mode orders. The obtained results are suitable for the edge emitting diode lasers and the external cavity lasers. The line shape of mode beating intensity noises is discussed based on CPO induced phase noise, giving explanations of the experimentally observed phenomenon of multiple sub peak spectra. The roles of intensity noise reduction by nonlinear optical absorber (NLA) inserted in the laser cavity are described. More factors related to the mode beating noise are discussed qualitatively, such as spectral hole burning of gain (SHB) the effect of external cavity, and higher order FWM.", "author_names": [ "Zujie Fang", "Fang Wei", "Kang Ying", "Qing Ye", "Haiwen Cai" ], "corpus_id": 231683711, "doc_id": "231683711", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Intensity Noise of Semiconductor Lasers Induced by Inter Mode Beating", "venue": "IEEE Journal of Quantum Electronics", "year": 2021 }, { "abstract": "The effect of optical feedback on the intensity noise spectrum and the longitudinal mode line shape of a 1.55 mm InGaAsP laser is investigated for reflections arising from the far end of a 7.5 km long fiber. The intensity noise near the relaxation oscillation frequency is significantly enhanced by the reflection feedback. Owing to the intercavity coupling, the enhancement is, however, frequency dependent and the noise spectrum exhibits high contrast modulations with a period corresponding to the fiber cavity longitudinal mode separation. A simple rate equation model is used to explain the observed behavior.", "author_names": [ "Govind P Agrawal", "Nils Anders Olsson", "Niloy K Dutta" ], "corpus_id": 120625008, "doc_id": "120625008", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Effect of fiber far end reflections on intensity and phase noise in InGaAsP semiconductor lasers", "venue": "", "year": 1984 }, { "abstract": "An exact result for the spectral density of intensity variations that occur after propagation of ergodic light in a medium having lowest order only group velocity dispersion is obtained and applied to the problem of semiconductor laser phase noise to intensity noise conversion in a single mode optical fiber. It is shown that the intensity spectrum after propagation formally approaches, for a large laser linewidth or a long (or high dispersion) fiber, the intensity spectrum of a thermal source having the same line shape as the laser.", "author_names": [ "William K Marshall", "Bruno Crosignani", "Amnon Yariv" ], "corpus_id": 17700597, "doc_id": "17700597", "n_citations": 66, "n_key_citations": 2, "score": 0, "title": "Laser phase noise to intensity noise conversion by lowest order group velocity dispersion in optical fiber: exact theory.", "venue": "Optics letters", "year": 2000 }, { "abstract": "1 Introduction. 2 Basic Laser Characteristics. 2.1 Double heterostructure characteristics. 2.2 Direct and indirect semiconductors. 2.2.1 Energy and momentum conservation. 2.2.2 Semiconductor materials for direct and indirect semiconductors. 2.3 Emission and absorption. 2.3.1 Density of photon oscillation states. 2.3.2 Principal mechanisms of radiative transitions. 2.3.3 Carrier lifetime and lifetime of spontaneous emission. 2.3.4 Gain and stimulated emission. 2.4 Lasing characteristics of Fabry Perot type lasers. 2.4.1 Lasing conditions. 2.4.2 Dynamic characteristics of laser operation. 2.4.3 Light current characteristics, threshold current and quantum efficiency. 2.4.4 Basic laser structures. 2.4.5 Modifications for the spontaneous emission term. 2.5 Dynamic single mode laser structures. 2.5.1 DFB laser characteristics. References. 3 Longitudinal Mode Spectrum of Lasing Emission. 3.1 Multimode rate equations. 3.2 Spectral envelope for Fabry 1 Introduction. 2 Basic Laser Characteristics. 2.1 Double heterostructure characteristics. 2.2 Direct and indirect semiconductors. 2.2.1 Energy and momentum conservation. 2.2.2 Semiconductor materials for direct and indirect semiconductors. 2.3 Emission and absorption. 2.3.1 Density of photon oscillation states. 2.3.2 Principal mechanisms of radiative transitions. 2.3.3 Carrier lifetime and lifetime of spontaneous emission. 2.3.4 Gain and stimulated emission. 2.4 Lasing characteristics of Fabry Perot type lasers. 2.4.1 Lasing conditions. 2.4.2 Dynamic characteristics of laser operation. 2.4.3 Light current characteristics, threshold current and quantum efficiency. 2.4.4 Basic laser structures. 2.4.5 Modifications for the spontaneous emission term. 2.5 Dynamic single mode laser structures. 2.5.1 DFB laser characteristics. References. 3 Longitudinal Mode Spectrum of Lasing Emission. 3.1 Multimode rate equations. 3.2 Spectral envelope for Fabry Perot type lasers (linear gain) 3.3 Influence of nonlinear gain on the spectral characteristics. 3.3.1 Symmetric nonlinear gain. 3.3.2 Asymmetric nonlinear gain. 3.3.3 Nonlinear gain, conclusions. References. 4 Intensity Modulation Characteristics of Laser Diodes. 4.1 Modulation characteristics by studying single mode rate equations. 4.1.1 Turn on delay. 4.1.2 Rate equations, small signal analysis. 4.1.3 Relaxation oscillation damping. 4.1.4 Upper limits for the modulation bandwidth of laser diodes. 4.2 Influence of lateral carrier diffusion on relaxation oscillation damping. 4.3 Modulation bandwidth limits due to parasitic elements. 4.4 Examples for high speed modulation of laser diodes. 4.5 Modulation and longitudinal mode spectrum. 4.5.1 Transient spectra of laser diodes. 4.5.2 Lasing spectra under high speed modulation. 4.5.3 Dynamic single mode condition. 4.6 Modulation with binary signals. 4.7 Harmonic and intermodulation distortions (without fibre interaction) 4.7.1 Harmonic and intermodulation distortions for low modulation frequencies. 4.7.2 Harmonic and intermodulation distortions for high modulation frequencies. References. 5 Frequency Modulation Characteristics of Laser Diodes. 5.1 Relation between intensity modulation and frequency modulation. 5.2 Current/frequency modulation characteristics. 5.3 Chirp effects in directly modulated laser diodes. 5.3.1 Spectral line broadening due to laser chirping. 5.3.2 Chirp reduction by proper pulse shaping. 5.3.3 Time bandwidth product of chirped pulses. 5.3.4 Transmission of chirped pulses over single mode fibres. 5.4 Possibilities of modifying the chirp parameter 5.4.1 Dispersion of the chirp parameter 5.4.2 Chirp of laser diodes, coupled to optical cavities. References. 6 Instabilities and Bistability in Laser Diodes. 6.1 Repetitive self pulsations due to lateral instabilities. 6.2 Instability and bistability in laser diodes with segmented contacts. References. 7 Noise Characteristics of Solitary Laser Diodes. 7.1 Relative intensity noise (RIN) 7.1.1 Basic properties of noise signals. 7.1.2 Definition and measurement of RIN. 7.1.3 Requirement of RIN for intensity modulated systems. 7.2 Introduction of the spontaneous emission noise. 7.3 Intensity noise of laser diodes. 7.3.1 Intensity noise of laser diodes by studying single mode rate equations. 7.3.2 Mode partition noise. 7.3.3 Mode partition noise analysis for nearly single mode lasers. 7.3.4 Mode hopping noise. 7.3.5 1/f intensity noise. 7.4 Statistics of intensity noise. 7.4.1 Statistics of amplified spontaneous emission. 7.4.2 Probability density distribution for the total laser light output. 7.4.3 Statistics of mode partition noise. 7.4.4 Turn on jitter in laser diodes. 7.5 Mode partition noise for the transmission of pulse code modulated (PCM) signals. 7.5.1 Multimode lasers. 7.5.2 The mode partition coefficient k. 7.5.3 Nearly single mode lasers. 7.6 Phase and frequency noise. 7.6.1 Phase and frequency noise characterization in general. 7.6.2 Spectral line shape for white frequency noise. 7.6.3 Spectral line shape for 1/f frequency noise. 7.6.4 Frequency noise and spectral linewidth for single mode laser diodes. 7.6.5 Power independent contribution to the linewidth of laser diodes. 7.6.6 Correlation between FM noise and AM noise. References. 8 Noise in Interferometers Including Modal Noise and Distortions. 8.1 Noise in interferometers. 8.1.1 Complex degree of coherence. 8.1.2 Interferometric noise analysis for single mode lasers. 8.1.3 Interferometric set ups for measuring the linewidth and the degree of coherence. 8.1.4 Interferometric noise analysis for multimode lasers. 8.2 Modal noise. 8.2.1 Modal noise for monochromatic light sources. 8.2.2 Modal noise for single mode lasers with finite spectral linewidth. 8.2.3 Modal noise for multimode laser diodes. 8.2.4 Modal distortions. 8.3 Modal noise and distortions in single mode fibres. References. 9 Semiconductor Lasers with Optical Feedback. 9.1 Amplitude and phase conditions for laser diodes with external cavities. 9.1.1 Short external reflectors for longitudinal mode stabilization. 9.1.2 Emission frequency shifts due to optical feedback. 9.1.3 Single external cavity mode condition. 9.1.4 Spectral linewidth for laser diodes with external optical feedback. 9.2 Dynamics of laser diodes with external reflections. 9.2.1 Derivation of the time dependent electric field. 9.2.2 Modulation characteristics of external cavity lasers. 9.3 Laser diodes with distant reflections. 9.3.1 Classification of feedback regimes. 9.3.2 Phase and frequency noise of laser diodes with distant reflectors. 9.3.3 Intensity noise in laser diodes with distant reflectors. 9.3.4 Coherence collapse. 9.3.5 Tolerable feedback levels. References. 10 Laser Diodes with Negative Electronic Feedback. 10.1 Modulation characteristics of laser diodes with negative electronic feedback. 10.2 Linewidth narrowing and phase noise reduction with negative electronic feedback. References. 11 Circuitry for Driving the Laser Diode. 11.1 Schemes for stabilizing the bias current. 11.2 Laser drivers with optoelectronic integration. References.", "author_names": [ "Klaus Petermann" ], "corpus_id": 118053992, "doc_id": "118053992", "n_citations": 921, "n_key_citations": 65, "score": 0, "title": "Laser Diode Modulation and Noise", "venue": "", "year": 1988 } ]

[ { "abstract": "Lead mixed halide perovskites are highly promising semiconductors for both multi junction photovoltaic and light emitting applications due to their tunable band gaps, with emission and absorption energies spanning the UV visible to near IR regions. However, many such perovskites exhibit unwanted halide segregation under photo illumination, the cause of which is still unclear. In our study, we establish crucial links between crystal phase stability, photostability and optoelectronic properties of the mixed cation lead mixed halide perovskite CsyFA(1 y)Pb(BrxI(1 x))3. We demonstrate a region for caesium content between 0.10 y 0.30 which features high crystalline quality, long charge carrier lifetimes and high charge carrier mobilities. Importantly, we show that for such high quality perovskites, photo induced halide segregation is strongly suppressed, suggesting that high crystalline quality is a prerequisite for good optoelectronic quality and band gap stability. We propose that regions of short range crystalline order aid halide segregation, possibly by releasing lattice strain between iodide rich and bromide rich domains. For an optimized caesium content, we explore the orthogonal halide variation parameter space for Cs0.17FA0.83Pb(BrxI(1 x))3 perovskites. We demonstrate excellent charge carrier mobilities (11 40 cm2 V 1 s 1) and diffusion lengths (0.8 4.4 mm) under solar conditions across the full iodide bromide tuning range. Therefore, the addition of caesium yields a more photo stable perovskite system whose absorption onsets can be tuned for bandgap optimized tandem solar cells.", "author_names": [ "Waqaas Rehman", "David P McMeekin", "Jay B Patel", "Rebecca L Milot", "Michael B Johnston", "Henry J Snaith", "Laura M Herz" ], "corpus_id": 53605415, "doc_id": "53605415", "n_citations": 260, "n_key_citations": 1, "score": 1, "title": "Photovoltaic mixed cation lead mixed halide perovskites: links between crystallinity, photo stability and electronic properties", "venue": "", "year": 2017 }, { "abstract": "Perovskites for tandem solar cells Improving the performance of conventional single crystalline silicon solar cells will help increase their adoption. The absorption of bluer light by an inexpensive overlying solar cell in a tandem arrangement would provide a step in the right direction by improving overall efficiency. Inorganic organic perovskite cells can be tuned to have an appropriate band gap, but these compositions are prone to decomposition. McMeekin et al. show that using cesium ions along with formamidinium cations in lead bromide iodide cells improved thermal and photostability. These improvements lead to high efficiency in single and tandem cells. Science, this issue p. 151 Addition of cesium cations creates a robust ideal inorganic organic perovskite absorber for tandem silicon solar cells. Metal halide perovskite photovoltaic cells could potentially boost the efficiency of commercial silicon photovoltaic modules from ~20 toward 30% when used in tandem architectures. An optimum perovskite cell optical band gap of ~1.75 electron volts (eV) can be achieved by varying halide composition, but to date, such materials have had poor photostability and thermal stability. Here we present a highly crystalline and compositionally photostable material, [HC(NH2)2]0.83Cs0.17Pb(I0.6Br0.4)3, with an optical band gap of ~1.74 eV, and we fabricated perovskite cells that reached open circuit voltages of 1.2 volts and power conversion efficiency of over 17% on small areas and 14.7% on 0.715 cm2 cells. By combining these perovskite cells with a 19% efficient silicon cell, we demonstrated the feasibility of achieving >25% efficient four terminal tandem cells.", "author_names": [ "David P McMeekin", "Golnaz Sadoughi", "Waqaas Rehman", "Giles E Eperon", "Michael Saliba", "Maximilian T Horantner", "Amir A Haghighirad", "Nobuya Sakai", "Lars Korte", "Bernd Rech", "Michael B Johnston", "Laura M Herz", "Henry J Snaith" ], "corpus_id": 206643942, "doc_id": "206643942", "n_citations": 1788, "n_key_citations": 9, "score": 0, "title": "A mixed cation lead mixed halide perovskite absorber for tandem solar cells", "venue": "Science", "year": 2016 }, { "abstract": "Mixed halide lead perovskites are becoming of paramount interest in the optoelectronic and photovoltaic research fields, offering band gap tunability, improved efficiency, and enhanced stability compared to their single halide counterparts. Formamidinium based mixed halide perovskites (FA MHPs) are critical to obtaining optimum solar cell performance. Here, we report a solvent free mechanochemical synthesis (MCS) method to prepare FA MHPs, starting with their parent compounds (FAPbX3; X Cl, Br, I) achieving compositions not previously accessible through the solvent synthesis (SS) technique. By probing local Pb environments in MCS FA MHPs using solid state nuclear magnetic resonance spectroscopy, along with powder X ray diffraction for long range crystallinity and reflectance measurements to determine the optical band gap, we show that MCS FA MHPs form atomic level solid solutions between Cl/Br and Br/I MHPs. Our results pave the way for advanced methods in atomic level structural understanding while offering a one pot synthetic approach to prepare MHPs with superior control of stoichiometry.", "author_names": [ "Abdelrahman M Askar", "Abhoy Karmakar", "Guy M Bernard", "Michelle Ha", "Victor V Terskikh", "Benjamin D Wiltshire", "Sahil D Patel", "Jonathan Fleet", "Karthik Shankar", "Vladimir K Michaelis" ], "corpus_id": 13683504, "doc_id": "13683504", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Composition Tunable Formamidinium Lead Mixed Halide Perovskites via Solvent Free Mechanochemical Synthesis: Decoding the Pb Environments Using Solid State NMR Spectroscopy.", "venue": "The journal of physical chemistry letters", "year": 2018 }, { "abstract": "Mixed halide perovskites have attracted a strong interest in the photovoltaic community as a result of their high power conversion efficiency and the solid opportunity to realise a low cost and industry scalable technology. Light soaking represents one of the most promising approach to reduce non radiative recombination processes and thus to optimise device performances. Here, we investigate the effects of 1 sun illumination on state of the art triple cation halide perovskite thin films Cs0.05(MA0.14, FA0.86)0.95 Pb (I0.84, Br0.16) by a combined optical and chemical characterization. Competitive passivation and degradation effects on perovskite transport properties have been analyzed by spectrally and time resolved quantitative imaging luminescence analysis and by X ray photoemission spectroscopy (XPS) We notice a clear improvement of the optoelectronic properties of the material, with a net increase of the Quasi Fermi Level Splitting and a corresponding decrease of methylammonium MA+ for short (up to one hour) light soaking time. However, after 5 hours of light soaking phase segregation and in depth oxygen penetration lead to a decrease of the charge mobility.", "author_names": [ "Stefania Cacovich", "Davina Messou", "Adrien Bercegol", "Solene Bechu", "Armelle Yaiche", "Hamza Shafique", "J -G Rousset", "Philip Schulz", "Muriel Bouttemy", "Laurent Lombez" ], "corpus_id": 220411430, "doc_id": "220411430", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Light Induced Passivation in Triple Cation Mixed Halide Perovskites: Interplay between Transport Properties and Surface Chemistry.", "venue": "ACS applied materials interfaces", "year": 2020 }, { "abstract": "Organic inorganic lead halide perovskites containing a mixture of iodide and bromide anions consistently perform better in donor acceptor heterojunction solar cells than the standard methylammonium lead triiodide material. This observation is counterintuitive, as it is generally expected for photovoltaic materials that heterogeneities and compositional disorder cause reduced carrier diffusion length and conversion efficiency. Here, we combine ultrafast photoinduced electroabsorption and broadband fluorescence up conversion spectroscopy measurements to scrutinize the carrier dynamics in mixed cations, mixed halide lead perovskite thin films. Our results evidence the formation of charge transfer excitons (CTE) across the boundaries of domains of various halide compositions. A global analysis of photoinduced transient Stark signals shows that CTE evolve gradually from Br rich to I rich domains over tens to hundreds of picoseconds. Rather than constituting recombination centres, boundaries between domains of various halide compositions appear then to favour charge carrier separation by driving photogenerated holes along channels of decreasing bromide content.", "author_names": [ "Marine E F Bouduban", "Fabrizio Giordano", "Arnulf Rosspeintner", "Joel Teuscher", "Eric Vauthey", "Michael Gratzel", "Jacques-E Moser" ], "corpus_id": 104661844, "doc_id": "104661844", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Inter Domain Charge Transfer as a Rationale for Superior Photovoltaic Performances of Mixed Halide Lead Perovskites", "venue": "", "year": 2018 }, { "abstract": "Tin halide perovskites are promising candidates for lead free photovoltaic and optoelectronic materials, but not all of them have been well characterized. It is essential to determine how the bulk photophysical properties are correlated with their structures at both short and long ranges. Although CsSnCl3 is normally stable in the cubic perovskite structure only above 379 K, it was prepared as a metastable phase at room temperature. The transition from the cubic to the monoclinic phase, which is the stable form at room temperature, was tracked by solid state 133Cs NMR spectroscopy and shown to take place through a first order kinetics process. The complete solid solution CsSn(Cl1 xBrx)3 (0 x 1) was successfully prepared, exhibiting cubic perovskite structures extending between the metastable CsSnCl3 and stable CsSnBr3 end members. The NMR spectra of CsSnBr3 samples obtained by three routes (high temperature, mechanochemical, and solvent assisted reactions) show distinct chemical shift ranges, spin lattice relaxation parameters and peak widths, indicative of differences in local structure, defects and degree of crystallinity within these samples. Variable temperature 119Sn spin lattice relaxation measurements reveal spontaneous mobility of Br atoms in CsSnBr3. The degradation of CsSnBr3, exposed to an ambient atmosphere for nearly a year, was monitored by NMR spectroscopy and powder X ray diffraction, as well as by optical absorption spectroscopy.", "author_names": [ "Abhoy Karmakar", "A J Bhattacharya", "Diganta Sarkar", "Guy M Bernard", "Arthur Mar", "Vladimir K Michaelis" ], "corpus_id": 233619816, "doc_id": "233619816", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Influence of hidden halogen mobility on local structure of CsSn(Cl1 xBrx)3 mixed halide perovskites by solid state NMR+", "venue": "Chemical science", "year": 2020 }, { "abstract": "Managing defects in SnO2 is critical for improving the power conversion efficiency (PCE) of halide perovskite based solar cells. However, typically reported SnO2 based perovskite solar cells have inherent defects in the SnO2 layer, which lead to a lower PCE and hysteresis. Here, we report that a dual coating approach for SnO2 with different annealing temperatures can simultaneously form a SnO2 layer with high crystallinity and uniform surface coverage. Along with these enhanced physical properties, the dual coated SnO2 layer shows favorable band alignment with a mixed halide perovskite. After careful optimization of the dual coating method, the average PCE of the perovskite solar cell based on the dual coated SnO2 layer increases from 18.07% to 19.23% with best performing cell of 20.03% Note that a facile two step coating and annealing method can open new avenues to develop SnO2 based perovskite solar cells with stabilized and improved photovoltaic performances.", "author_names": [ "Jung Hwan Lee", "Dongguen Shin", "Ryan Rhee", "Sang Geun Yun", "Kyung Mun Yeom", "Do Hyung Chun", "Sunje Lee", "Dongho Kim", "Yeonjin Yi", "Jun Hong Noh", "Jong Hyeok Park" ], "corpus_id": 203985579, "doc_id": "203985579", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Band Alignment Engineering between Planar SnO2 and Halide Perovskites via Two Step Annealing.", "venue": "The journal of physical chemistry letters", "year": 2019 }, { "abstract": "Due to their high power conversion efficiency, organic inorganic lead halide perovskites have emerged as promising materials for next generation solar cell devices. As the efficiency race continues for this revolutionary class of light harvesting materials, many questions about the structural, electronic and optical properties of perovskite solar cells have still to be addressed. More particularly, the long term stability of this kind of devices is an open question because various different crystalline phases exist in a narrow temperature range.[1] Mixed cation lead halide perovskites have attracted wide attention due to the possibility of tackling the problem of limited phase stability. Through a theoretical analysis of the phase stability of binary formamidinium (FA) rich, cesiumrich FA/Cs and guanidinium (GUA)/FA mixtures as well as ternary Cs/GUA/FA mixtures, we propose a series of design principles for the synthesis of stable mixed cation lead halide perovskites that could be potential candidates for solar cell applications.[2] In addition to this, an understanding of the correlations between different photophysical properties and the atomistic characteristics of these materials is paving the way for the design of lead halide perovskites with enhanced optical properties.[3] For this reason, the anomalous low temperature behavior of the photoluminescence spectra of cesium lead bromide is rationalized in terms of the structural characteristics of the material at low temperatures.", "author_names": [ "Ariadni Boziki" ], "corpus_id": 204113235, "doc_id": "204113235", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Computational studies of the structural and optical properties of organic inorganic lead halide perovskites.", "venue": "", "year": 2019 }, { "abstract": "Quasi two dimensional (2D) mixed cation hybrid halide perovskites (A'2AN 1MNX3N+1; A' large organic molecule with cationic group, A [Cs+ CH3NH3+ HC(NH2)2+ M [Pb, Sn, Ge] X [I Br Cl have rapidly emerged as candidates to improve the structural stability and device lifetime of 3D perovskite semiconductor devices under operating conditions. The addition of the large A' cation to the traditional AMX3 structure introduces several synthetic degrees of freedom and breaks M X bonds, giving rise to peculiar critical phase behavior in the phase space of these complex materials. In this work, we propose a thermodynamic model parametrized by first principles calculations to generate the phase diagram of 2D and quasi 2D perovskites (q 2DPKs) based on the mechanics and electrostatics of the interface between the A' cations and the metal halide octahedral network. Focusing on the most commonly studied methylammonium lead iodide system where A' is n butylammonium (BA; CH3(CH2)3NH3+ we find that the apparent difficulty in synthesizing phase pure samples with a stoichiometric index N 5 can be attributed to the energetic competition between repulsion of opposing interfacial dipole layers and mechanical relaxation induced by interfacial stress. Our model shows quantitative agreement with experimental observations of the maximum phase pure stoichiometric index (Ncrit) and explains the non monotonic evolution of the lattice parameters with increasing stoichiometric index (N) This model is generalizable to the entire family of q 2DPKs and can guide the design of photovoltaic and optical materials that combine the structural stability of the q 2DPKs while retaining the charge carrier properties of their 3D counterparts.", "author_names": [ "Christopher C Price", "Jean-Christophe Blancon", "Aditya D Mohite", "Vivek B Shenoy" ], "corpus_id": 211214124, "doc_id": "211214124", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Interfacial Electromechanics Predicts Phase Behavior of 2D Hybrid Halide Perovskites.", "venue": "ACS nano", "year": 2020 }, { "abstract": "The development of smart illumination sources represents a central challenge for current technology. In this context, the quest for novel materials that enable efficient light generation is essential. Metal halide compounds with perovskite crystalline structure (ABX3) have gained tremendous interest in the last five years since they come as easy to prepare high performance semiconductors. Perovskite absorbers are driving the power conversion efficiencies of thin film photovoltaics to unprecedented values. Nowadays, mixed cation, mixed halide lead perovskite solar cells reach efficiencies consistently over 20% and promise to get close to 30% in multijunction devices when combined with silicon cells at no surcharge. Nonetheless, perovskites' fame extends further since extensive research on these novel semiconductors has also revealed their brightest side. Soon after their irruption in the photovoltaic scenario, demonstration of efficient color tunable with high color purity perovskite emitters has opened new avenues for light generation applications that are timely to discuss herein.", "author_names": [ "Gabriel Lozano" ], "corpus_id": 49471094, "doc_id": "49471094", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "The Role of Metal Halide Perovskites in Next Generation Lighting Devices", "venue": "The journal of physical chemistry letters", "year": 2018 } ]

[ { "abstract": "Full C and L band tuning of a compact, MEMS tuned external cavity semiconductor laser is obtained using a MEMS actuated lens to switch between resonator configurations, including one configuration that tunes continuously over 5 THz.", "author_names": [ "Douglas William Anthon", "Jill D Berger", "A A Tselikov" ], "corpus_id": 19557383, "doc_id": "19557383", "n_citations": 17, "n_key_citations": 0, "score": 1, "title": "C+L band MEMS tunable external cavity semiconductor laser", "venue": "Optical Fiber Communication Conference, 2004. OFC 2004", "year": 2004 }, { "abstract": "We propose and demonstrate a novel approach to achieving rapid and phase coherent continuous broadband tuning of a single mode external cavity semiconductor laser. Two internal acousto optic devices control the angle of incident light on a diffraction grating and the effective round trip phase electronically. Although the present implementation derives the phase from a long delay line and is not yet mode hop free, the new approach lends itself to fully electronic control.", "author_names": [ "Motonobu Kourogi", "Kazuhiro Imai", "Bagus Widyatmoko", "T Shimizu", "Motoichi Ohtsu" ], "corpus_id": 32790996, "doc_id": "32790996", "n_citations": 16, "n_key_citations": 0, "score": 1, "title": "Continuous tuning of an electrically tunable external cavity semiconductor laser.", "venue": "Optics letters", "year": 2000 }, { "abstract": "An external cavity semiconductor laser employing a birefringent electro optic modulator for wavelength tuning is described. Wide band tuning over 70 A in a single frequency to residual diode modes and narrow band tuning over 0.42 A to many longitudinal modes of the external cavity is demonstrated using different modulator configurations. Threshold current and quantum efficiency are nearly as good as that of the solitary laser diode.", "author_names": [ "Alfred T Schremer", "C L Tang" ], "corpus_id": 120639547, "doc_id": "120639547", "n_citations": 18, "n_key_citations": 0, "score": 1, "title": "Single frequency tunable external cavity semiconductor laser using an electro optic birefringent modulator", "venue": "", "year": 1989 }, { "abstract": "An external cavity diode laser is demonstrated to emit greater than 1.0 W CW in a diffraction limited radiation pattern. The laser wavelength is tunable over a 35 nm span centred at 852 nm.", "author_names": [ "David G Mehuys", "Dave Welch", "Donald R Scifres" ], "corpus_id": 121203841, "doc_id": "121203841", "n_citations": 39, "n_key_citations": 0, "score": 1, "title": "1 W CW, diffraction limited, tunable external cavity semiconductor laser", "venue": "", "year": 1993 }, { "abstract": "Abstract A tunable dual wavelength fiber ring cavity laser based on semiconductor optical amplifier (SOA) using two external injected distributed feedback (DFB) lasers is proposed and experimentally demonstrated. When one of the injected DFB lasers operates at 25 degC and the other at 0 degC, a stable dual wavelength simultaneous oscillation at 1553.68 nm and 1553.90 nm with a wavelength spacing of 0.22 nm is achieved. The wavelength spacing can be tuned by adjusting the operating temperatures of the two injected DFB lasers, and a tuning range from 0.22 nm to 2.95 nm is obtained. Our experimental results demonstrate the new concept of dual wavelength fiber ring cavity laser using two DFB lasers injection and the technical feasibility.", "author_names": [ "Wei Cao", "Min Luo", "Hai-yan Chen" ], "corpus_id": 125426059, "doc_id": "125426059", "n_citations": 2, "n_key_citations": 0, "score": 2, "title": "A tunable dual wavelength fiber ring cavity laser based on semiconductor optical amplifier using two external injected DFB lasers", "venue": "Optik", "year": 2019 }, { "abstract": "Abstract Combination of equivalent reflection cavity model and transmission line theory is applied in theoretical analysis of external cavity semiconductor lasers with sampled fiber Bragg grating. The effects of device parameters on the resonant cavity mode and the side mode suppression ratio have been discussed. For a perfect anti coated facet and the high coupling efficiency, it is found that the Vernier effect between combed reflectivity peaks and F P cavity modes can be destroyed and the laser will work on multi wavelength. The high coupling efficiency plays the same role as the lower anti reflection coating reflectivity in the side mode suppression ratio and the mode resonance. Finally, the side mode suppression ratio is investigated in detail depending on the anti coating reflectivity, the coupling efficiency and the high reflection coating reflectivity.", "author_names": [ "Xiaoying He", "Wei Li", "Jun Zhang", "Xiaodong Huang", "Jiang Shan", "Dexiu Huang" ], "corpus_id": 121902320, "doc_id": "121902320", "n_citations": 10, "n_key_citations": 2, "score": 1, "title": "Theoretical analysis of widely tunable external cavity semiconductor laser with sampled fiber grating", "venue": "", "year": 2006 }, { "abstract": "We report a continuous wave highly coherent and tunable dual frequency laser emitting at two frequencies separated by 30 GHz to 3 THz, based on compact III V diode pumped quantum well surface emitting semiconductor laser technology. The concept is based on the stable simultaneous operation of two Laguerre Gauss transverse modes in a single axis short cavity, using an integrated sub wavelength thick metallic mask. Simultaneous operation is demonstrated theoretically and experimentally by recording intensity noises and beat frequency, and time resolved optical spectra. We demonstrated a >80 mW output power, diffraction limited beam, narrow linewidth of <300 kHz, linear polarization state >45 dB) and low intensity noise class A dynamics of <0.3% rms, thus opening the path to a compact low cost coherent GHz to THz source development.", "author_names": [ "Romain Paquet", "Stephane Blin", "Mikhael Myara", "Luc le Gratiet", "Mohamed Sellahi", "Baptiste Chomet", "Gregoire Beaudoin", "Isabelle Sagnes", "Arnaud Garnache" ], "corpus_id": 23157126, "doc_id": "23157126", "n_citations": 23, "n_key_citations": 4, "score": 1, "title": "Coherent continuous wave dual frequency high Q external cavity semiconductor laser for GHz THz applications.", "venue": "Optics letters", "year": 2016 }, { "abstract": "", "author_names": [ "Chen Shao Wei Chen Shaowei", "Lu Xue Qin Lu Xueqin", "Zhang Jiang Yong Zhang Jiangyong", "Ying Lei Ying Ying Leiying", "Zhang Bao Ping Zhang Baoping" ], "corpus_id": 124566109, "doc_id": "124566109", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Blue Violet Broadly Tunable Grating Coupled External Cavity Semiconductor Laser", "venue": "", "year": 2013 }, { "abstract": "The main objective of this study is to develop a near infrared (NIR) tunable external cavity laser (ECL) that is based on a semiconductor optical amplifier and two different wavelength selective elements. In order to achieve the wavelength selection, several filters have been tested in the ECL setups, including plasmonic filter, acoustooptic tunable filter (AOTF) gradient photonic crystal and Fabry Perot (FP) cavity filter. The results show that the AOTF and FP filter have been applied successfully in the ECL system as wavelength selective elements to demonstrate a broadband wavelength tuning in the range between 830 nm and 870 nm. The tunable ECL realized with the variation of electrical radio frequency input of AOTF or incident angle of FP cavity filter from 15.5deg to 30deg in each system. By controlling the wavelength selective elements, continuous tuning of ECL over 30 nm can be achieved and 23 lasing peaks were measured and analyzed in the laser system with FP cavity filter. The characteristics of the AOTF based and FP based tunable ECL, including I V curve, threshold, tuning range and output power, are measured and reported in this thesis.", "author_names": [ "Zhiyong Han" ], "corpus_id": 54612298, "doc_id": "54612298", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Tunable External Cavity Ring Laser with Wavelength Selective Elements", "venue": "", "year": 2018 }, { "abstract": "We demonstrate high power (2.1W) low noise single frequency operation of a tunable compact verical external cavity surface emitting laser exhibiting a high beam quality. We took advantage of thermal lens based stability to develop a short (3 10 mm) plano plano external cavity without any intracavity filter. The semiconductor structure emitting at 1microm is optically pumped by a 8W commercial 808 nm multimode diode laser at large incidence angle. For heat management purpose the GaAs based VECSEL membrane was bonded on a SiC substrate. We measured a low divergence quasi circular TEM00 beam (M2 1.2) close to diffraction limit, with a linear light polarization >30 dB).We simulated the steady state laser beam of this unstable cavity using Fresnel diffraction. The side mode suppression ratio is 45 dB. The free running laser linewidth is 37 kHz limited by pump induced thermal fluctuations. Thanks to this high Q external cavity approach, the frequency noise is low and the dynamics is in the relaxation oscillation free regime, exhibiting low intensity noise 0.1% with a cutoff frequency approximately 41MHz above which the shot noise level is reached. The key parameters limiting the laser power and coherence are studied. This design/properties can be extended to other wavelengths.", "author_names": [ "Alexandre Laurain", "Mikhael Myara", "Gregoire Beaudoin", "Isabelle Sagnes", "Arnaud Garnache" ], "corpus_id": 43221063, "doc_id": "43221063", "n_citations": 102, "n_key_citations": 6, "score": 1, "title": "Multiwatt power highly coherent compact single frequency tunable vertical external cavity surface emitting semiconductor laser.", "venue": "Optics express", "year": 2010 } ]

[ { "abstract": "Significance Advances in miniaturization paved the way for tiny medical devices that circumvent conventional surgical implantation, but no suitable method for powering them deep in the body has been demonstrated. Existing methods for energy storage, harvesting, or transfer require large components that do not scale to millimeter dimensions. We report a wireless powering method that overcomes this challenge by inducing spatially focused and adaptive electromagnetic energy transport via propagating modes in tissue. We use the method to realize a tiny electrostimulator that is orders of magnitude smaller than conventional pacemakers. The demonstrated performance characteristics far exceed requirements for advanced electronic function and should enable new generations of miniaturized electronic implants. The ability to implant electronic systems in the human body has led to many medical advances. Progress in semiconductor technology paved the way for devices at the scale of a millimeter or less \"microimplants\" but the miniaturization of the power source remains challenging. Although wireless powering has been demonstrated, energy transfer beyond superficial depths in tissue has so far been limited by large coils (at least a centimeter in diameter) unsuitable for a microimplant. Here, we show that this limitation can be overcome by a method, termed midfield powering, to create a high energy density region deep in tissue inside of which the power harvesting structure can be made extremely small. Unlike conventional near field (inductively coupled) coils, for which coupling is limited by exponential field decay, a patterned metal plate is used to induce spatially confined and adaptive energy transport through propagating modes in tissue. We use this method to power a microimplant (2 mm, 70 mg) capable of closed chest wireless control of the heart that is orders of magnitude smaller than conventional pacemakers. With exposure levels below human safety thresholds, milliwatt levels of power can be transferred to a deep tissue >5 cm) microimplant for both complex electronic function and physiological stimulation. The approach developed here should enable new generations of implantable systems that can be integrated into the body at minimal cost and risk.", "author_names": [ "John S Ho", "Alexander J Yeh", "Evgenios A Neofytou", "Sanghoek Kim", "Yuji Tanabe", "Bhagat Patlolla", "Ramin E Beygui", "Ada S Y Poon" ], "corpus_id": 15227901, "doc_id": "15227901", "n_citations": 326, "n_key_citations": 18, "score": 1, "title": "Wireless power transfer to deep tissue microimplants", "venue": "Proceedings of the National Academy of Sciences", "year": 2014 }, { "abstract": "Wireless power transfer (WPT) plays critical roles in powering deep tissue implants, which also contributes to several emerging advances for biomedical engineering. To enable a high power density region in implants, this article presents a method, termed the self phasing technology, to focus electromagnetic fields from various paths at a deep tissue spot. By performing the phase conjugated operation on the incident signal and then retransfer back to the source, coherent RF power can be achieved without learning the precise or even dynamic locations of sources and concerning inhomogeneous medium perturbations. An external slot antenna array placed above skin surface 4 mm is considered as a transmitter and an implanted rectenna consisting of a magnetic resonant coil and an RF to dc rectifier circuit is treated as a receiver. The conversion efficiency of the rectifier circuit is optimized within the received power range and the measured efficiency of 50% can be achieved at 0 dBm. To visualize the transceiver effects of the integrated system under safety thresholds, a light emitting diode (LED) is soldered at the terminal of the rectenna and measurements show that smooth drive can be achieved. Certain brightness of LED can demonstrate that the self phasing technology can support WPT for biomedical applications.", "author_names": [ "Kecheng Zhang", "Changrong Liu", "Zhi Hao Jiang", "Yudi Zhang", "Xue-guan Liu", "Huiping Guo", "Xinmi Yang" ], "corpus_id": 210005869, "doc_id": "210005869", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Near Field Wireless Power Transfer to Deep Tissue Implants for Biomedical Applications", "venue": "IEEE Transactions on Antennas and Propagation", "year": 2020 }, { "abstract": "In future wireless implants, tiny sensor nodes may be used for detection and treatment of various diseases and for monitoring therapeutic activities. This requires ultralow power tiny sensors implantable inside different body organs. This letter presents a biomedical RFID system meant for wireless interrogation of deep tissue millimeter size implant sensors. The communication system is based on using a repeater device that amplifies the attenuated downlink power and thus extends sensor read distance. This system enables monitoring of different body organs by placing miniature sensor implants inside them. This letter studies wireless power transmission in this system through fabrication of the antennas and conducting two port wireless link measurements.", "author_names": [ "Elham Moradi", "Lauri Sydanheimo", "George Steven Bova", "Leena Ukkonen" ], "corpus_id": 9677264, "doc_id": "9677264", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Measurement of Wireless Power Transfer to Deep Tissue RFID Based Implants Using Wireless Repeater Node", "venue": "IEEE Antennas and Wireless Propagation Letters", "year": 2017 }, { "abstract": "This paper proposes a biomedical RFID system meant for wireless interrogation of deep tissue mm size implant sensors. The communication system is based on using a repeater device that amplifies the attenuated downlink power and thus extends sensor read distance. This system enables monitoring of different body organs by placing miniature sensor implants inside them. The repeater device should also be implanted in the wireless power path from external reader to the sensor implant in a safe place not disturbing any body functions.", "author_names": [ "Elham Moradi", "Lauri Sydanheimo", "Leena Ukkonen", "George Steven Bova" ], "corpus_id": 41386693, "doc_id": "41386693", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Wireless power transfer to deep tissue mm size implants using wireless repeater node", "venue": "2016 Loughborough Antennas Propagation Conference (LAPC)", "year": 2016 }, { "abstract": "Midfield wireless power transfer has proved its advantages in power delivery to miniature implantable medical devices located deeply in the human body; however, the delivered power level is still low. Besides, design proposals for a compact source structure concentrating the transmitter field on a miniature implant remain challenges. This letter presents a novel compact transmitting structure (TX) at the midfield band and shows the capability of focusing the magnetic field inside the human tissue. Source performance has been verified by implantable planar inverted F antenna (PIFA) with a total size of 9 x 13 mm$^2} (RX) that positioned in the heart tissue layer at a 55 mm separated distance of TX and RX. In addition, the power transfer efficiency has been demonstrated by a measurement setup using pork muscle, which obtained a good match of the transmission coefficient between the simulation and experiment results. Consequently, for 1 W of output power from the midfield transmitter, the received energy could be achieved more than 5.6 mW via the implantable antenna at a subwavelength distance.", "author_names": [ "Ngan Nguyen", "Nam Ha-Van", "Chulhun Seo" ], "corpus_id": 226605336, "doc_id": "226605336", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Midfield Wireless Power Transfer for Deep Tissue Biomedical Implants", "venue": "IEEE Antennas and Wireless Propagation Letters", "year": 2020 }, { "abstract": "Passive operation and battery charging of deep body implants can be insured through wireless power transfer (WPT) technologies. However, the power transfer efficiency (PTE) is constrained by device miniaturization and implantation depth. This study proposes a complete WPT system consisting of a patterned WPT transmitter (Tx) an efficient rectifier, and an antenna integrated with the system. The WPT Tx had a size of 6 cm <inline formula> <tex math notation=\"LaTeX\"\\times$ /tex math>/inline formula> 6 cm and was optimized to focus the power on the deep tissue implants at 1470 MHz. The voltage doubler was optimized at 1470 MHz, had a small size of 5 mm <inline formula> <tex math notation=\"LaTeX\"\\times$ /tex math>/inline formula> 10 mm, and exhibited a high radio frequency (RF) to direct current (dc) conversion efficiency of 90% at 2 dBm RF input power. Moreover, the implantable antenna occupies a small volume of 8.43 mm³ and supports quad band operations: telemetry at 403 and 915 MHz, WPT at the midfield band of 1470 MHz, and control signaling at 2.4 GHz. First, the fabricated prototypes were measured individually in minced pork, in the American Society for Testing and Materials (ASTM) model, and in the saline filled 3 D head phantom. While operating collectively as an integrated system, the PTE of the system was measured. Additionally, to enhance the PTE of the WPT system, a high dielectric matching layer <inline formula> <tex math notation=\"LaTeX\"\\varepsilon _{r} 78$ /tex math>/inline formula> was used between the WPT Tx and the phantom. Furthermore, to demonstrate the PTE of the WPT system, the voltage doubler was integrated with the implantable antenna, encapsulated in a 3 D printed capsule endoscope, and its PTE was measured in a saline solution and minced pork. Finally, the compliance of the WPT system with the human safety standards was analyzed and found that the system solely satisfied the safety limits. It is evident from the experimental results that the system can transfer 6.7 mW power to millimeter sized implants located 5 cm deep in tissues.", "author_names": [ "Abdul Basir", "Hyoungsuk Yoo" ], "corpus_id": 213959276, "doc_id": "213959276", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Efficient Wireless Power Transfer System With a Miniaturized Quad Band Implantable Antenna for Deep Body Multitasking Implants", "venue": "IEEE Transactions on Microwave Theory and Techniques", "year": 2020 }, { "abstract": "In this study, we introduce a triple band flexible implantable antenna that is tuned by using a ground slot in three specific bands, namely Medical Implanted Communication Service (MICS: 402 405 MHz) for telemetry, the midfield band (lower gigahertz: 1.45 1.6 GHz) for Wireless Power Transfer (WPT) and the Industrial, Scientific and Medical band (ISM: 2.4 2.45 GHz) for power conservation. The telemetry performance of the proposed antenna was simulated and measured by using a porcine heart. To check the feasibility of WPT, a midfield transmitter antenna was introduced. In addition, to reduce the unwanted power leakage due to WPT, a Near Field Plate (NFP) was also used. Finally, power conservation can be realized by triggering the antennas sleep mode in the ISM band.", "author_names": [ "Rupam Das", "Hyoungsuk Yoo" ], "corpus_id": 13428455, "doc_id": "13428455", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A triple band deep tissue implantable antenna incorporating biotelemetry and unidirectional wireless power transfer system", "venue": "2017 IEEE International Symposium on Antennas and Propagation USNC/URSI National Radio Science Meeting", "year": 2017 }, { "abstract": "In this study, we introduce a triple band flexible implantable antenna that is tuned by using a ground slot in three specific bands, namely Medical Implanted Communication Service (MICS: 402~405 MHz) for telemetry, the midfield band (lower gigahertz: 1.45~1.6 GHz) for Wireless Power Transfer (WPT) and the Industrial, Scientific and Medical band (ISM: 2.4~2.45 GHz) for power conservation. The telemetry performance of the proposed antenna was simulated and measured by using a porcine heart. To check the feasibility of WPT, a midfield transmitter antenna was introduced. In addition, to reduce the unwanted power leakage due to WPT, a Near Field Plate (NFP) was also used. Finally, power conservation can be realized by triggering the antenna's `sleep mode' in the ISM band.", "author_names": [ "Rupam Das", "Youngdae Cho", "Hyoungsuk Yoo" ], "corpus_id": 6927325, "doc_id": "6927325", "n_citations": 4, "n_key_citations": 1, "score": 0, "title": "High efficiency unidirectional wireless power transfer by a triple band deep tissue implantable antenna", "venue": "2016 IEEE MTT S International Microwave Symposium (IMS)", "year": 2016 }, { "abstract": "", "author_names": [ "Tracy A Hampton" ], "corpus_id": 72331069, "doc_id": "72331069", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wireless System Transfers Power to Deep Tissue Microimplants", "venue": "", "year": 2014 }, { "abstract": "Mid field wireless power transfer (MF WPT) is a scheme developed for transcutaneous power transfer to microimplants kept deep inside the body in GHz frequency.With deep seated implants, the possible locations available for application increases to almost the entire body. But, this advantage of applicability is severely limited as the power delivered to the micro implants by MF WPT is very low in the range of few 100W. Yet, the mid field operations have higher efficiency in miniaturized weakly coupled coil implants compared to traditional near field system. So, with improvement in certain aspects, MF WPT is expected to play a vital role in biomedical field. For the same reason this paper focuses on analyses of literature available in various aspects of MF WPT, its challenges, drawbacks and future scope of the scheme in medical field.", "author_names": [ "K Keerthi", "K Ilango", "G N Manjula" ], "corpus_id": 53426776, "doc_id": "53426776", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Study of Midfield Wireless Power Transfer for Implantable Medical Devices", "venue": "2018 2nd International Conference on Biomedical Engineering (IBIOMED)", "year": 2018 } ]

[ { "abstract": "", "author_names": [ "W Liu", "Yin Zhizhen", "Xiaoming Chen", "Zhenyun Peng", "Song Helun", "Liu Peihua", "Xinhai Tong", "Yaohui Zhang" ], "corpus_id": 103223591, "doc_id": "103223591", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "A secret key distribution technique based on semiconductor superlattice chaos devices", "venue": "", "year": 2018 }, { "abstract": "Resonances in quantum transport are observed through chaos assisted tunneling with a quantum gas in a shaken optical lattice. The field of quantum simulation, which aims at using a tunable quantum system to simulate another, has been developing fast in the past years as an alternative to the all purpose quantum computer. So far, most efforts in this domain have been directed to either fully regular or fully chaotic systems. Here, we focus on the intermediate regime, where regular orbits are surrounded by a large sea of chaotic trajectories. We observe a quantum chaos transport mechanism, called chaos assisted tunneling, that translates in sharp resonances of the tunneling rate and provides previously unexplored possibilities for quantum simulation. More specifically, using Bose Einstein condensates in a driven optical lattice, we experimentally demonstrate and characterize these resonances. Our work paves the way for quantum simulations with long range transport and quantum control through complexity.", "author_names": [ "M Arnal", "G Chatelain", "M Martinez", "Niels Dupont", "Olivier Giraud", "Denis Ullmo", "Bertrand Georgeot", "Gabriel Lemari'e", "Juliette Billy", "D Guery-Odelin" ], "corpus_id": 214611790, "doc_id": "214611790", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Chaos assisted tunneling resonances in a synthetic Floquet superlattice", "venue": "Science Advances", "year": 2020 }, { "abstract": "Noise enhanced chaos in a doped, weakly coupled GaAs/Al_{0.45}Ga_{0.55}As superlattice has been observed at room temperature in experiments as well as in the results of the simulation of nonlinear transport based on a discrete tunneling model. When external noise is added, both the measured and simulated current versus time traces contain irregularly spaced spikes for particular applied voltages, which separate a regime of periodic current oscillations from a region of no current oscillations at all. In the voltage region without current oscillations, the electric field profile consist of a low field domain near the emitter contact separated by a domain wall consisting of a charge accumulation layer from a high field regime closer to the collector contact. With increasing noise amplitude, spontaneous chaotic current oscillations appear over a wider bias voltage range. For these bias voltages, the domain boundary between the two electric field domains becomes unstable and very small current or voltage fluctuations can trigger the domain boundary to move toward the collector and induce chaotic current spikes. The experimentally observed features are qualitatively very well reproduced by the simulations. Increased noise can consequently enhance chaotic current oscillations in semiconductor superlattices.", "author_names": [ "Zhizhen Yin", "Helun Song", "Yaohui Zhang", "Miguel Ruiz-Garcia", "Manuel Carretero", "Luis L Bonilla", "Klaus Biermann", "Holger T Grahn" ], "corpus_id": 31010535, "doc_id": "31010535", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Noise enhanced chaos in a weakly coupled GaAs/(Al,Ga)As superlattice.", "venue": "Physical review. E", "year": 2017 }, { "abstract": "When quantized, traces of classically chaotic single particle systems include eigenvalue statistics and scars in eigenfuntions. Since 2001, many theoretical and experimental works have argued that classically chaotic single electron dynamics influences and controls collective electron transport. For transport in semiconductor superlattices under tilted magnetic and electric fields, these theories rely on a reduction to a one dimensional self consistent drift model. A two dimensional theory based on self consistent Boltzmann transport does not support that single electron chaos influences collective transport. This theory agrees with existing experimental evidence of current self oscillations, predicts spontaneous collective chaos via a period doubling scenario, and could be tested unambiguously by measuring the electric potential inside the superlattice under a tilted magnetic field.", "author_names": [ "Luis L Bonilla", "Manuel Carretero", "Antigona Segura" ], "corpus_id": 1779629, "doc_id": "1779629", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Two dimensional collective electron magnetotransport, oscillations, and chaos in a semiconductor superlattice.", "venue": "Physical review. E", "year": 2017 }, { "abstract": "We investigate the effects of a linear resonator on the high frequency dynamics of electrons in devices exhibiting negative differential conductance. We show that the resonator strongly affects both the dc and ac transport characteristics of the device, inducing quasiperiodic and high frequency chaotic current oscillations. The theoretical findings are confirmed by experimental measurements of a GaAs/AlAs miniband semiconductor superlattice coupled to a linear microstrip resonator. Our results are applicable to other active solid state devices and provide a generic approach for developing modern chaos based high frequency technologies including broadband chaotic wireless communication and superfast random number generation.", "author_names": [ "Alexander E Hramov", "Vladimir V Makarov", "Alexey A Koronovskii", "Semen A Kurkin", "Marat B Gaifullin", "Natalia V Alexeeva", "Kirill N Alekseev", "M T Greenaway", "T Mark Fromhold", "Amalia Patane", "Feodor V Kusmartsev", "Vladimir A Maksimenko", "Olga I Moskalenko", "Alexander G Balanov" ], "corpus_id": 13708150, "doc_id": "13708150", "n_citations": 51, "n_key_citations": 2, "score": 0, "title": "Subterahertz chaos generation by coupling a superlattice to a linear resonator.", "venue": "Physical review letters", "year": 2014 }, { "abstract": "We investigate the onset of broadband microwave chaos in the miniband semiconductor superlattice coupled to an external resonator. Our analysis shows that the transition to chaos, which is confirmed by calculation of Lyapunov exponents, is associated with the intermittency scenario. The evolution of the laminar phases and the corresponding Poincare maps with variation of a supercriticality parameter suggest that the observed dynamics can be classified as type I intermittency. We study the spatiotemporal patterns of the charge concentration and discuss how the frequency band of the chaotic current oscillations in semiconductor superlattice depends on the voltage applied.", "author_names": [ "Alexander E Hramov", "Vladimir V Makarov", "Vladimir A Maximenko", "Alexey A Koronovskii", "Alexander G Balanov" ], "corpus_id": 28029638, "doc_id": "28029638", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Intermittency route to chaos and broadband high frequency generation in semiconductor superlattice coupled to external resonator.", "venue": "Physical review. E, Statistical, nonlinear, and soft matter physics", "year": 2015 }, { "abstract": "The transition to chaos in a semiconductor superlattice coupled to an external resonator is studied. It is shown that the transition to chaos proceeds through intermittency. It is found that the system exhibits broadband generation regimes, which is of direct interest for the practical use of nanostructures in data transmission systems.", "author_names": [ "Vladimir V Makarov", "Alexander E Hramov", "Alexey A Koronovskii", "Olga I Moskalenko", "Vladimir A Maksimenko", "Kirill N Alekseev", "Alexander G Balanov" ], "corpus_id": 53122388, "doc_id": "53122388", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Transition to chaos and chaotic generation in a semiconductor superlattice coupled to an external resonator", "venue": "", "year": 2014 }, { "abstract": "The transition to chaos in semiconductor superlattice coupled to external resonant system had been investigated. We have shown that transition to chaos goes through type I intermittency in the system under study. This fact is approved by dependence of the mean laminar phase length versus criticality parameter, and form of Poincare mapping.", "author_names": [ "Vladimir V Makarov", "Alexander E Hramov", "Aleksei Koronovskii", "Vladimir A Maximenko", "Alexander G Balanov" ], "corpus_id": 27725673, "doc_id": "27725673", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Transition to chaos in semiconductor superlattice coupled to external resonator", "venue": "2014 24th International Crimean Conference Microwave Telecommunication Technology", "year": 2014 }, { "abstract": "The chaos in Bose Einstein condensate (BEC) in a 1 D tilted optical superlattice potential is studied numerically in this paper. Numerical analysis using the Gross Pitaevskii (G P) equation for the system with attractive interaction reveals that as the tilt of the optical superlattice potential is increased the chaos in the BEC increases. This makes the system more unstable and the phase space orbit increases. The chaos increases as the secondary optical lattice potential increases.", "author_names": [ "Priyanka Verma", "A Bhattacherjee", "Man Mohan" ], "corpus_id": 120058229, "doc_id": "120058229", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Chaos in BEC trapped in tilted optical superlattice potential with attractive interaction", "venue": "", "year": 2012 }, { "abstract": "We have shown that the application of modulating the secondary lattice is an efficient route to suppressing the generation of chaotic traveling waves of a Bose Einstein Condensate with attractive interatomic interaction loaded into a moving optical superlattice consisting of two lattices. With the Melnikov method, we obtain the optimal value of the relative phase between the two lattice harmonics for the control of chaos. We also find that the regularization route as the potential depth of the secondary lattice is varied and fairly rich, including the period doubling bifurcations.", "author_names": [ "Luo Xiao-bing", "Xia Xiu-wen", "Zhang Xiaofei" ], "corpus_id": 122345616, "doc_id": "122345616", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Suppression of Chaos in a Bose Einstein Condensate Loaded into a Moving Optical Superlattice Potential", "venue": "", "year": 2010 } ]

[ { "abstract": "Hydrocarbons contamination of the marine environment generated by the offshore oil and gas industry is generated from a number of sources including oil contaminated drill cuttings and produced waters. The removal of hydrocarbons from both these sources is one of the most significant challenges facing this sector as it moves towards zero emissions. The application of a number of techniques which have been used to successfully destroy hydrocarbons in produced water and waste water effluents has previously been reported. This paper reports the application of semiconductor photocatalysis as a final polishing step for the removal of hydrocarbons from two waste effluent sources. Two reactor concepts were considered: a simple flat plate immobilised film unit, and a new rotating drum photocatalytic reactor. Both units proved to be effective in removing residual hydrocarbons from the effluent with the drum reactor reducing the hydrocarbon content by 90% under 10 minutes.", "author_names": [ "Morgan Adams", "Ian Campbell", "Peter K J Robertson" ], "corpus_id": 54036505, "doc_id": "54036505", "n_citations": 31, "n_key_citations": 2, "score": 1, "title": "Novel photocatalytic reactor development for removal of hydrocarbons from water", "venue": "", "year": 2008 }, { "abstract": "Arsenic's history in science, medicine and technology has been overshadowed by its notoriety as a poison in homicides. Arsenic is viewed as being synonymous with toxicity. Dangerous arsenic concentrations in natural waters is now a worldwide problem and often referred to as a 20th 21st century calamity. High arsenic concentrations have been reported recently from the USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungary, Japan and India. Among 21 countries in different parts of the world affected by groundwater arsenic contamination, the largest population at risk is in Bangladesh followed by West Bengal in India. Existing overviews of arsenic removal include technologies that have traditionally been used (oxidation, precipitation/coagulation/membrane separation) with far less attention paid to adsorption. No previous review is available where readers can get an overview of the sorption capacities of both available and developed sorbents used for arsenic remediation together with the traditional remediation methods. We have incorporated most of the valuable available literature on arsenic remediation by adsorption approximately 600 references) Existing purification methods for drinking water; wastewater; industrial effluents, and technological solutions for arsenic have been listed. Arsenic sorption by commercially available carbons and other low cost adsorbents are surveyed and critically reviewed and their sorption efficiencies are compared. Arsenic adsorption behavior in presence of other impurities has been discussed. Some commercially available adsorbents are also surveyed. An extensive table summarizes the sorption capacities of various adsorbents. Some low cost adsorbents are superior including treated slags, carbons developed from agricultural waste (char carbons and coconut husk carbons) biosorbents (immobilized biomass, orange juice residue) goethite and some commercial adsorbents, which include resins, gels, silica, treated silica tested for arsenic removal come out to be superior. Immobilized biomass adsorbents offered outstanding performances. Desorption of arsenic followed by regeneration of sorbents has been discussed. Strong acids and bases seem to be the best desorbing agents to produce arsenic concentrates. Arsenic concentrate treatment and disposal obtained is briefly addressed. This issue is very important but much less discussed.", "author_names": [ "Dinesh Mohan", "Charles U Pittman" ], "corpus_id": 13291593, "doc_id": "13291593", "n_citations": 2765, "n_key_citations": 100, "score": 0, "title": "Arsenic removal from water/wastewater using adsorbents A critical review.", "venue": "Journal of hazardous materials", "year": 2007 }, { "abstract": "A screening method was developed to evaluate the oil removal capability of biosurfactants for oil contaminated soils collected from a heavy oil polluted site. The ability of removing total petroleum hydrocarbon (TPH) from soil by two biosurfactants was identified and compared with that of synthetic surfactants. The results show that biosurfactants exhibited much higher TPH removal efficiency than the synthetic ones examined. By using 0.2 mass% of rhamnolipids, surfactin, Tween 80, and Triton X 100, the TPH removal for the soil contaminated with ca. 3,000 mg TPH/kg dry soil was 23% 14% 6% and 4% respectively, while removal efficiency increased to 63% 62% 40% and 35% respectively, for the soil contaminated with ca. 9000 mg TPH/kg dry soil. The TPH removal efficiency also increased with an increase in biosurfactant concentration (from 0 to 0.2 mass% but it did not vary significantly for the contact time of 1 and 7 days.", "author_names": [ "Chin Chi Lai", "Yi-Chien Huang", "Yu-Hong Wei", "Jo-Shu Chang" ], "corpus_id": 25684314, "doc_id": "25684314", "n_citations": 310, "n_key_citations": 10, "score": 0, "title": "Biosurfactant enhanced removal of total petroleum hydrocarbons from contaminated soil.", "venue": "Journal of hazardous materials", "year": 2009 }, { "abstract": "In the present study electrocoagulation (EC) has been evaluated as a treatment technology for arsenite [As(III) and arsenate [As(V) removal from water. Laboratory scale experiments were conducted with three electrode materials namely, iron, aluminum and titanium to assess their efficiency. Arsenic removal obtained was highest with iron electrodes. EC was able to bring down aqueous phase arsenic concentration to less than 10 microgl( 1) with iron electrodes. Current density was varied from 0.65 to 1.53 mAcm( 2) and it was observed that higher current density achieved rapid arsenic removal. Experimental results at different current densities indicated that arsenic removal was normalized with respect to total charge passed and therefore charge density has been used to compare the results. Effect of pH on arsenic removal was not significant in the pH range 6 8. Comparative evaluation of As(III) and As(V) removal by chemical coagulation (with ferric chloride) and electrocoagulation has been done. The comparison revealed that EC has better removal efficiency for As(III) whereas As(V) removal by both processes was nearly same. The removal mechanism of As(III) by EC seems to be oxidation of As(III) to As(V) and subsequent removal by adsorption/complexation with metal hydroxides generated in the process.", "author_names": [ "P Ratna Kumar", "Sanjeev Chaudhari", "Kartic C Khilar", "S P Mahajan" ], "corpus_id": 29813636, "doc_id": "29813636", "n_citations": 511, "n_key_citations": 19, "score": 0, "title": "Removal of arsenic from water by electrocoagulation.", "venue": "Chemosphere", "year": 2004 }, { "abstract": "Nitrate contamination in groundwater resources originates mainly from the excessive use of fertilisers and uncontrolled land discharges of treated wastewater. This can cause potential health hazards to infants and pregnant women, thus limiting the direct use of the groundwater resources for the human consumption in several parts of the world, including India. The conventional processes used to eliminate nitrate from water are ion exchange, reverse osmosis and electro dialysis. The utility of these processes has been limited due to their expensive operation and subsequent disposal problem of the generated nitrate waste brine. This paper presents a comprehensive account of the methods/techniques used for the removal of nitrate ion from water during the last 10 years with special reference to the biological denitrification and fate of the metals in decontamination processes.", "author_names": [ "Madhusudan Shrimali", "K P Singh" ], "corpus_id": 43053292, "doc_id": "43053292", "n_citations": 362, "n_key_citations": 8, "score": 0, "title": "New methods of nitrate removal from water.", "venue": "Environmental pollution", "year": 2001 }, { "abstract": "Phytoremediation is an emerging technology that uses plants to clean up pollutants (metals and organics) from the environment. Within this field of phytoremediation, the utilization of plants to transport and concentrate metals from the soil into the harvestable parts of roots and above ground shoots is usually called phytoextraction. Most traditional remediation methods do not provide acceptable solutions for the removal of metals from soils. By contrast, phytoextraction of metals is a cost effective approach that uses metal accumulating plants to clean up these soils. Subsequently, the harvestable parts, rich in accumulated metals, can be easily and safely processed by drying, ashing or composting. Some extracted metals can also be reclaimed from the ash, generating recycling revenues. Phytoextraction appears a very promising technology for the removal of metal pollutants from the environment and may be, at present, approaching commercialization.", "author_names": [ "Carlos Garbisu", "Itziar Alkorta" ], "corpus_id": 12689247, "doc_id": "12689247", "n_citations": 842, "n_key_citations": 29, "score": 0, "title": "Phytoextraction: a cost effective plant based technology for the removal of metals from the environment.", "venue": "Bioresource technology", "year": 2001 }, { "abstract": "Carbon nanotube (CNT) adsorption technology has the potential to support point of use (POU) based treatment approach for removal of bacterial pathogens, natural organic matter (NOM) and cyanobacterial toxins from water systems. Unlike many microporous adsorbents, CNTs possess fibrous shape with high aspect ratio, large accessible external surface area, and well developed mesopores, all contribute to the superior removal capacities of these macromolecular biomolecules and microorganisms. This article provides a comprehensive review on application of CNTs as adsorbent media to concentrate and remove pathogens, NOM, and cyanobacterial (microcystin derivatives) toxins from water systems. The paper also surveys on consideration of CNT based adsorption filters for removal of these contaminants from cost, operational and safety standpoint. Based on the studied literature it appears that POU based CNT technology looks promising, that can possibly avoid difficulties of treating biological contaminants in conventional water treatment plants, and thereby remove the burden of maintaining the biostability of treated water in the distribution systems.", "author_names": [ "Venkata K K Upadhyayula", "S Deng", "Martha C Mitchell", "Geoffrey B Smith" ], "corpus_id": 6592664, "doc_id": "6592664", "n_citations": 532, "n_key_citations": 20, "score": 0, "title": "Application of carbon nanotube technology for removal of contaminants in drinking water: a review.", "venue": "The Science of the total environment", "year": 2009 }, { "abstract": "The available technologies for the abatement of phenol from water and gaseous streams are briefly reviewed, and the recent advancements summarized. Separation technologies such as distillation, liquid liquid extraction with different solvents, adsorption over activated carbons and polymeric and inorganic adsorbents, membrane pervaporation and membrane solvent extraction, have been discussed. Destruction technologies such as non catalytic, supercritical and catalytic wet air oxidation, ozonation, non catalytic, catalytic and enzymatic peroxide wet oxidation, electrochemical and photocatalytic oxidation, supercritical wet gasification, destruction with electron discharges as well as biochemical treatments have been considered. As for the abatement of phenol from gases, condensation, absorption in liquids, adsorption on solids, membrane separation, thermal, catalytic, photocatalytic and biological oxidation have also been considered. The experimental conditions and the performances of the different techniques have been compared.", "author_names": [ "Guido Busca", "Silvia Berardinelli", "Carlo Resini", "Laura Arrighi" ], "corpus_id": 24997944, "doc_id": "24997944", "n_citations": 1038, "n_key_citations": 49, "score": 0, "title": "Technologies for the removal of phenol from fluid streams: a short review of recent developments.", "venue": "Journal of hazardous materials", "year": 2008 }, { "abstract": "Among various water purification and recycling technologies, adsorption is a fast, inexpensive and universal method. The development of low cost adsorbents has led to the rapid growth of research interests in this field. The present protocol describes salient features of adsorption and details experimental methodologies for the development and characterization of low cost adsorbents, water treatment and recycling using adsorption technology including batch processes and column operations. The protocol describes the development of inexpensive adsorbents from waste materials, which takes only 1 2 days, and an adsorption process taking 15 120 min for the removal of pollutants. The applications of batch and column processes are discussed, along with suggestions to make this technology more popular and applicable.", "author_names": [ "Imran Ali", "V K Gupta" ], "corpus_id": 6436105, "doc_id": "6436105", "n_citations": 1017, "n_key_citations": 10, "score": 0, "title": "Advances in water treatment by adsorption technology", "venue": "Nature Protocols", "year": 2007 }, { "abstract": "Nitrate, due to its high water solubility, is possibly the most widespread groundwater contaminant in the world, imposing a serious threat to human health and contributing to eutrophication. Among several treatment technologies applied for nitrate removal, adsorption has been explored widely and offers satisfactory results especially with mineral based and/or surface modified adsorbents. In this review, an extensive list of various sorbents from the literature has been compiled and their adsorption capacities for nitrate removal as available in the literature are presented along with highlighting and discussing the key advancement on the preparation of novel adsorbents tested for nitrate removal.", "author_names": [ "Amit Bhatnagar", "Mika Sillanpaa" ], "corpus_id": 96907327, "doc_id": "96907327", "n_citations": 524, "n_key_citations": 14, "score": 0, "title": "A review of emerging adsorbents for nitrate removal from water", "venue": "", "year": 2011 } ]

[ { "abstract": "Abstract This review paper encompasses a detailed study of semiconductor metal oxide (SMO) gas sensors. It provides for a detailed comparison of SMO gas sensors with other gas sensors, especially for ammonia gas sensing. Different parameters which affect the performance (sensitivity, selectivity and stability) of SMO gas sensors are discussed here under. This paper also gives an insight about the dopant or impurity induced variations in the SMO materials used for gas sensing. It is concluded that dopants enhance the properties of SMOs for gas sensing applications by changing their microstructure and morphology, activation energy, electronic structure or band gap of the metal oxides. In some cases, dopants create defects in SMOs by generating oxygen vacancy or by forming solid solutions. These defects enhance the gas sensing properties. Different nanostructures (nanowires, nanotubes, heterojunctions) other than nanopowders have also been studied in this review. At the end, examples of SMOs are given to illustrate the potential use of different SMO materials for gas sensing.", "author_names": [ "Ananya Dey" ], "corpus_id": 104271227, "doc_id": "104271227", "n_citations": 667, "n_key_citations": 7, "score": 1, "title": "Semiconductor metal oxide gas sensors: A review", "venue": "", "year": 2018 }, { "abstract": "", "author_names": [ "K Govardhan", "G Nirmala" ], "corpus_id": 99090593, "doc_id": "99090593", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Metal/Metal Oxide Doped Semiconductor Based Metal Oxide Gas Sensors A Review", "venue": "", "year": 2016 }, { "abstract": "Abstract Semiconductor metal oxide nanowires (SMO NWs) show great potential for novel gas sensor applications because of their distinct properties, such as a high surface area to volume aspect ratio, high crystallinity and perfect pathway for electron transfer (length of NW) SMO NW sensors can be configured as resistors or field effect transistors for gas detection and different configurations, such as a single NW, multiple NWs, and networked NW films, have been established. Surface functionalizing NWs with catalyst elements and self heating NWs provide additional advantages for highly selective and low power consumption gas sensors. However, an appropriate design of SMO NWs is of practical importance in enhancing the gas sensing performance of SMO NW sensors. The on chip growth of SMO NWs possesses many advantages which can thus be effectively used for the large scale fabrication of SMO NW sensors with improved gas response and stability. This review aims to provide up to date information on the on chip fabrication of SnO2, ZnO, WO3, CuO, and other SMO NW sensors. It also discusses a variety of promising approaches that help advance the on chip fabrication of SMO NW based gas sensors and other NW based devices.", "author_names": [ "Chu Manh Hung", "Dang Thi Thanh Le", "Nguyen Van Hieu" ], "corpus_id": 116446441, "doc_id": "116446441", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "On chip growth of semiconductor metal oxide nanowires for gas sensors: A review", "venue": "", "year": 2017 }, { "abstract": "Conductometric gas sensors facilitated by photons have been investigated for decades. Light illumination may enhance device attributes including operational temperature, sensing sensitivity and selectivity. This paper aims to provide an overview on the progress of light activated gas sensors, with a specific focus on sensors based on metal oxides. The material systems that have been studied include pure metal oxides, heterostructures of semiconductor metal oxides and metal metal oxides, and metal oxides with dopant. Other reported works on the use of different nanostructures such as one dimensional and porous nanostructures, study of sensing mechanisms and the interplay between various factors are also summarized. Possible directions for further improvement of sensing properties, through optimizing the size of nanomaterials, film thickness, light intensity and wavelength are discussed. Finally, we point out that the main challenge faced by light activated gas sensors is their low optical response, and we have analyzed the feasibility of using localized surface plasmon resonance to solve this drawback. This article should offer readers some key and instructive insights into the current and future development of light activated gas sensors.", "author_names": [ "Fang Xu", "Ho-Pui Ho" ], "corpus_id": 52214278, "doc_id": "52214278", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Light Activated Metal Oxide Gas Sensors: A Review", "venue": "Micromachines", "year": 2017 }, { "abstract": "This paper gives a statistical view about important contributions and advances on semiconductor metal oxide (SMO) compounds based gas sensors developed to detect the air pollutants such as liquefied petroleum gas (LPG) H2S, NH3, CO2, acetone, ethanol, other volatile compounds and hazardous gases. Moreover, it is revealed that the alloy/composite made up of SMO gas sensors show better gas response than their counterpart single component gas sensors, i.e. they are found to enhance the 4S characteristics namely speed, sensitivity, selectivity and stability. Improvement of such types of sensors used for detection of various air pollutants, which are reported in last two decades, is highlighted herein.", "author_names": [ "S J Patil", "Arun Vitthal Patil", "C G Dighavkar", "K S Thakare", "Ratan Yadav Borase", "S J Nandre", "Nishad G Deshpande", "R R Ahire" ], "corpus_id": 98399093, "doc_id": "98399093", "n_citations": 75, "n_key_citations": 1, "score": 0, "title": "Semiconductor metal oxide compounds based gas sensors: A literature review", "venue": "Frontiers of Materials Science", "year": 2015 }, { "abstract": "Surface acoustic wave (SAW) gas sensors are of continuous development interest to researchers due to their sensitivity, short detection time, and reliability. Among the most used materials to achieve the sensitive film of SAW sensors are metal oxide semiconductors, which are highlighted by thermal and chemical stability, by the presence on their surface of free electrons and also by the possibility of being used in different morphologies. For different types of gases, certain metal oxide semiconductors are used, and ZnO is an important representative for this category of materials in the field of sensors. Having a great potential for the development of SAW sensors, the discussion related to the development of the sensitivity of metal oxide semiconductors, especially ZnO, by the synthesis method or by obtaining new materials, is suitable and necessary to have an overview of the latest results in this domain.", "author_names": [ "Izabela Constantinoiu", "Cristian Viespe" ], "corpus_id": 221624681, "doc_id": "221624681", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "ZnO Metal Oxide Semiconductor in Surface Acoustic Wave Sensors: A Review", "venue": "Sensors", "year": 2020 }, { "abstract": "In modern world, gas sensors play important role in many fields of technology used for air pollution, breath analysis, public safety and many others. Gas sensor based semiconductor metal oxide is mostly used in these applications because of low cost, ease to use, high sensitivity and lower power consumption. This paper gives an overview about the semiconductor metal oxide and reviews why using it as sensing of gases in electrical applications and then it addresses to the work mechanism of a sensor to sensing H2S gas.", "author_names": [ "Zaid Hameed Mahmoud", "Omar Dhaa Abdalstar", "Noor us Sabah" ], "corpus_id": 225382953, "doc_id": "225382953", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Semiconductor Metal Oxide Nanoparticles: A Review for the Potential of H2S Gas Sensor Application", "venue": "", "year": 2020 }, { "abstract": "Abstract Air pollution is nowadays a big issue regarding the health of human beings. Among the toxic gases emitted in the atmosphere, NO2 is the most problematic one and a lot of countries or cities want to monitor its concentration in order to be able to take measures to reduce it. Therefore, it is urgent to develop NO2 sensors with high performance, low power consumption and low cost. Several technologies have been developed for this purpose. A very popular technology is based on metal oxide semiconductor. The usual semiconductor gas sensors need to be operated at high temperature, but nowadays many efforts are put on metal oxide sensors that can work at room temperature. These sensors present many advantages: low power consumption, low manufacturing cost, as well as moderate stability and safety. However, due to the weak response to NO2 at room temperature, most semiconductor NO2 sensors need to be adapted. This review will present the main strategies and material modification methods studied so far. These include light illumination, sensitization with an organic, formation of heterojunctions, preparation of composites with 1D or 2D materials and an introduction of oxygen vacancies in high concentrations. The gas sensing mechanisms of these sensors are presented and discussed.", "author_names": [ "C Zhang", "Yifan Luo", "Jiaqiang Xu", "Marc Debliquy" ], "corpus_id": 117703669, "doc_id": "117703669", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Room temperature conductive type metal oxide semiconductor gas sensors for NO2 detection", "venue": "Sensors and Actuators A: Physical", "year": 2019 }, { "abstract": "Abstract Flammable, explosive and toxic gases, such as hydrogen, hydrogen sulfide and volatile organic compounds vapor, are major threats to the ecological environment safety and human health. Among the available technologies, gas sensing is a vital component, and has been widely studied in literature for early detection and warning. As a metal oxide semiconductor, zinc ferrite (ZnFe2O4) represents a kind of promising gas sensing material with a spinel structure, which also shows a fine gas sensing performance to reducing gases. Due to its great potentials and widespread applications, this article is intended to provide a review on the latest development in zinc ferrite based gas sensors. We first discuss the general gas sensing mechanism of ZnFe2O4 sensor. This is followed by a review of the recent progress about zinc ferrite based gas sensors from several aspects: different micro morphology, element doping and heterostructure materials. In the end, we propose that combining ZnFe2O4 which provides unique microstructure (such as the multi layer porous shells hollow structure) with the semiconductors such as graphene, which provide excellent physical properties. It is expected that the mentioned composites contribute to improving selectivity, long term stability, and other sensing performance of sensors at room or low temperature.", "author_names": [ "Kaidi Wu", "Jianzhi Li", "C Zhang" ], "corpus_id": 139599993, "doc_id": "139599993", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "Zinc ferrite based gas sensors: A review", "venue": "Ceramics International", "year": 2019 }, { "abstract": "Abstract Metal oxide semiconductor (MOS) gas sensors possess extensive applications due to their high sensitivity, low cost, and simplicity. To boost their excellent sensing performance and meet the growing demand for applications, a series of strategies have been developed, such as the surface morphology engineering and function manipulation. Recently, the controlled morphology with exposed high energy facets and the facet dependent sensing properties have attracted much attention. Because of its abundant unsaturated active sites, the crystal planes with high surface energy usually serve as promising platform for gas sensing. After a lot of survey of literature, the authors provide a review of recent efforts on engineering crystal structures with exposed high energy facets of MOS nanomaterials and their improved gas sensitive performance, emphasis on six kinds of common gas sensitive MOS including ZnO, SnO2, TiO2, a Fe2O3, NiO and Cu2O. Also, the relationship between dangling bonds density and gas sensing properties has been systematically discussed and used as one significant factor to evaluate superior sensing surface of MOS. According to the research and calculation, surface engineering by selectively exposing high energy facets provides an effective way to obtain MOS gas sensitive materials with superior performance. The understanding of the facet dependent properties of MOS will assist in and guide the fabrication of more excellent gas sensors in the future.", "author_names": [ "Xing Gao", "Tong Zhang" ], "corpus_id": 104933227, "doc_id": "104933227", "n_citations": 119, "n_key_citations": 3, "score": 0, "title": "An overview: Facet dependent metal oxide semiconductor gas sensors", "venue": "", "year": 2018 } ]

[ { "abstract": "Abstract Nanostructured CdS thin film was successfully deposited on glass by chemical bath deposition (CBD) at 80 degC. The effect of deposition time on the morphology, composition, optical and optoelectronic properties of nanostructured CdS thin films has been studied. The CBD grown CdS thin films showed random arrangement of interconnected nanoparticles in 2D morphology. Nanostructured CdS thin films exhibited metastable cubic phase having uniform, compact and defect free structure with enhanced crystallinity. Tauc plot of CBD grown nanostructured CdS thin film showed an optimum band gap of 2.30 eV and a resonant Raman peak at 302 cm 1. The transverse optics (TO) mode, multi phonon scattering and high order replicas of nanostructured CdS thin films were also observed. Metal semiconductor metal (MSM) based CdS Photodetector (PD) showed an excellent photodetectivity of 2.6 x 1013 Jones. Photoconductive performance such as photo sensitivity (207% and responsivity (0.38 A/W 420 nm) under an illumination condition was obtained for application in visible light photodetector.", "author_names": [ "Manmohansingh Waldiya", "R Narasimman", "Dharini Bhagat", "Dhaval Vankhade", "Indrajit Mukhopadhyay" ], "corpus_id": 139611453, "doc_id": "139611453", "n_citations": 16, "n_key_citations": 0, "score": 1, "title": "Nanoparticulate CdS 2D array by chemical bath deposition: Characterization and optoelectronic study", "venue": "Materials Chemistry and Physics", "year": 2019 }, { "abstract": "Lead sulfide thin films were prepared at 25 degC temperature using chemical bath deposition (CBD) on both Si (100) and glass substrates. XRD analysis of the PbS film shows that the prepared films have a polycrystalline structure with (200) preferential orientation. The grains become smaller with increasing the deposition concentration. X ray photoelectron spectroscopy (XPS) demonstrated the presence of lead sulfide as PbS. The composition of the prepared films is investigated by energy dispersive X ray spectroscopy technique, and it was found that the films are stoichiometric and have low oxygen contamination. Raman and XPS spectra confirm that the CBD method is a decent one to acquire stoichiometric PbS film with nanostructures. Atomic force microscopy was applied to investigate the change in the films morphology with the concentration. The effect of the concentration, on both optical transmittance in the UV NIR region and the structure of the film, was studied. The results revealed that the optical band gap increased slightly when the concentration increased together with the grain size evolution.", "author_names": [ "Bassam Abdallah", "Reham Hussein", "Nedal Al-Kafri", "W Zetoun" ], "corpus_id": 127017074, "doc_id": "127017074", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "PbS Thin Films Prepared by Chemical Bath Deposition: Effects of Concentration on the Morphology, Structure and Optical Properties", "venue": "Iranian Journal of Science and Technology, Transactions A: Science", "year": 2019 }, { "abstract": "Abstract Flower like Ni(OH)2 nanostructured was synthesized by using simple chemical bath deposition (CBD) method as a binder free electrode for supercapacitor. The nanowalls with thickness 50 70 nm were connected to each other forming pores, which further results in higher electrochemical performance by the virtue of easy transportation of electrolyte and ions to active mass. The maximum specific capacitance of flower like Ni(OH)2 is found 1065 F g 1 at current density 15 mA s 1 with excellent rate capability.", "author_names": [ "P E Lokhande", "Umesh S Chavan" ], "corpus_id": 103635504, "doc_id": "103635504", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Nanoflower like Ni(OH) 2 synthesis with chemical bath deposition method for high performance electrochemical applications", "venue": "", "year": 2018 }, { "abstract": "Abstract Copper antimony sulfide (CAS) has been proposed as low toxicity and earth abundant absorber materials for thin film photovoltaics due to their suitable optical band gap, high absorption coefficient and p type electrical conductivity. The present work reports the formation of copper antimony sulfide by chemical bath deposition using sodium citrate as a complexing agent. We show that by tuning the annealing condition, one can obtain either chalcostibite or tetrahedrite phase. However, the main challenge was co deposition of copper and antimony as ternary sulfides from a single chemical bath due to the distinct chemical behavior of these metals. The as deposited films were subjected to several trials of thermal treatment using different temperatures and time to find the optimized annealing condition. The films were characterized by different techniques including Raman spectroscopy, X ray diffraction (XRD) profilometer, scanning electron microscopy (SEM) UV vis spectrophotometer, and Hall Effect measurements. The results show that the formation of chalcostibite and tetrahedrite phases is highly sensitive to annealing conditions. The electrical properties obtained for the chalcostibite films varied as the annealing temperature increases from 280 to 350 degC: hole concentration (n) 1017 1018 cm 3, resistivity (r) 1.74 2.14 Ocm and carrier mobility (m) 4.7 9.26 cm2/Vseg. While for the tetrahedrite films, the electrical properties were n 5 x 1019 cm 3, m 18.24 cm2/Vseg, and r 5.8 x 10 3 Ocm. A possible mechanism for the formation of ternary copper antimony sulfide has also been proposed.", "author_names": [ "F E Loranca-Ramos", "C J Diliegros-Godines", "Rutilo Silva Gonzalez", "Mou Pal" ], "corpus_id": 104131235, "doc_id": "104131235", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "Structural, optical and electrical properties of copper antimony sulfide thin films grown by a citrate assisted single chemical bath deposition", "venue": "", "year": 2018 }, { "abstract": "Abstract Lead sulfide nanocrystal films, comprising of well faceted 350 nm cubic nanocrystals are tailored by ion flux controlled chemical bath deposition at 50 degC to 80 degC bath temperatures. These possess compact (111) oriented nanocubic morphology and exhibit significantly improved electrical and opto electronic properties as necessary for emerging next generation solar energy conversion applications. All films are of p type nature and concurrently possess high carrier mobility (u) high hole concentration (p) and low electrical resistivity (r) at room temperature. In particular, for films grown at 75 degC, high values of u 29.3 cm2V 1s 1, p 8.1x1017 cm 3 and r 0.26 O cm are observed on the same nanocubic film. At high temperatures (T 150 K) the charge transport is governed by thermally activated band conduction and nearest neighbour hopping conduction. However, at lower temperatures (T", "author_names": [ "Rekha Bai", "Sujeet Chaudhary", "Dinesh K Pandya" ], "corpus_id": 103687550, "doc_id": "103687550", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Temperature dependent charge transport mechanisms in highly crystalline p PbS cubic nanocrystals grown by chemical bath deposition", "venue": "", "year": 2018 }, { "abstract": "Abstract Growth of highly transparent and hydrophilic ZnS thin films on flexible polymeric and glass substrates has been performed using an environmentally friendly chemical bath deposition method with an ammonia and thioacetamide free reaction solution. Deposition time effect on surface morphology, structure and optical properties of the ZnS thin films has been investigated by field emission scanning electron microscopy (FE SEM) atomic force microscopy (AFM) transmission electron microscopy (TEM) X ray diffractometer (XRD) ultraviolet visible light (UV vis) spectroscopy, and photoluminescence (PL) spectroscopy. Also, the chemical composition of the prepared films has been studied in detail by energy dispersive X ray spectrometer (EDX) X ray photoelectron spectroscopy (XPS) and Raman spectroscopy. TEM images show that the ZnS films consisted of small nanocrystals with diameters =5 nm. Moreover, the water contact angles, 38.5deg and 25.4deg for ZnS films deposited on PS and on glass substrates, respectively, indicate a highly hydrophilic nature. Undoubtedly, the chemical analysis shows the formation of the films with a chemical composition of ZnS0.89, lacking impurities such as ZnO and/or Zn (OH)2. Additionally, FE SEM images show a homogenous deposition over a very large surface area substrates. Ultimately, the obtained photoluminescence spectrum indicates a strong and broad emission peak ranging from 400 to 600 nm, which are due to deep levels or trap state defects in the crystalline structure of the ZnS films.", "author_names": [ "Ayat Karimi", "Beheshteh Sohrabi", "Mohammad Reza Vaezi" ], "corpus_id": 102761712, "doc_id": "102761712", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Highly transparent, flexible and hydrophilic ZnS thin films prepared by a facile and environmentally friendly chemical bath deposition method", "venue": "", "year": 2018 }, { "abstract": "A simple, low temperature route for the chemical bath deposition of Mg doped ZnO films, based on low cost, abundant and non toxic materials was developed. The film growth mechanism, the resulting morphology and texture were investigated in detail by scanning electron microscopy and X ray diffraction measurements. It was found that substantial film growth is only possible in a narrow solution pH window due to the Zn(OH)2 supersaturation as driving force for the film deposition. Different amounts of Mg in the solution cause distinct (0001) (10$ \\bar{1} $1 0) or (10$ \\bar{1} $1 1) ZnO crystal textures. Speciation modelling helped to understand the solution chemistry and explain the occurrence of different textures by face selective adsorption of Mg species onto specific ZnO faces. The amount of incorporated Mg into the ZnO lattice, determined by inductively coupled plasma atomic emission spectroscopy, was limited to 2.1 mol% Optical band gaps, calculated from transmittance spectra, showed an increase with higher amounts of incorporated Mg and ranged between 3.41 and 3.55 eV.", "author_names": [ "Nina Winkler", "Stefan Edinger", "Wolfgang Kautek", "Theodoros Dimopoulos" ], "corpus_id": 103846042, "doc_id": "103846042", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Mg doped ZnO films prepared by chemical bath deposition", "venue": "Journal of Materials Science", "year": 2018 }, { "abstract": "This study presents a comparison of the piezoelectric properties of nanostructured thin films made of arrays of vertically oriented ZnO nanorods (ZnO NRs) over ITO glass substrate and of ZnO nanowalls (ZnO NWs) over aluminium substrate. Both nanostructures were synthesized on a large area through chemical bath deposition. The morphological, structural, and chemical characteristics of the produced nanostructures were investigated in order to assess the crystal quality and purity. To this purpose, we used different techniques, such as field emission scanning electron microscopy, atomic force microscopy, energy dispersive x ray analysis, powder x ray diffraction, x ray photoelectron spectroscopy, and photoluminescence spectroscopy. Moreover, the piezoelectric response of the nanostructured films was assessed through piezoresponse force microscopy. This technique was employed to obtain a quantitative evaluation of the piezoelectric coefficient <inline formula><tex math notation=\"LaTeX\"{d_{33}/tex math>/inline formula> of the film. We obtained <inline formula><tex math notation=\"LaTeX\"{d_{33}/tex math>/inline formula> values as high as (7.01 0.33) pm/V for ZnO NRs and (2.63 0.49) pm/V for ZnO NWs films.", "author_names": [ "Marco Fortunato", "Chandrakanth Reddy Chandraiahgari", "Giovanni De Bellis", "Paolo Ballirano", "Peiman Soltani", "Saulius Kaciulis", "Luisa Caneve", "Francesca Sarto", "Maria Sabrina Sarto" ], "corpus_id": 3825020, "doc_id": "3825020", "n_citations": 13, "n_key_citations": 2, "score": 0, "title": "Piezoelectric Thin Films of ZnO Nanorods/Nanowalls Grown by Chemical Bath Deposition", "venue": "IEEE Transactions on Nanotechnology", "year": 2018 }, { "abstract": "Abstract Cu 2 S and Cu 2 O composite (Cu 2 S@Cu 2 O) film with micro/nano binary structure was created on copper surface using the mixing solution of sodium thiosulphate and copper sulfate by a facile chemical bath deposition method. After modification with low cost polydimethylsioxane (PDMS) the superhydrophobic Cu 2 S@Cu 2 O film was obtained. The as prepared film shows outstanding water repellency with a water contact angle larger than 150deg and long term storage stability. The geometric morphology and chemical composition of the film were characterized by scanning electron microscope (SEM) energy dispersive spectrometer (EDS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR) respectively. Moreover, the same method was used to fabricate superhydrophobic/superoleophilic copper mesh, and it could realize separation of various oily sewages with separation efficiency above 94% This strategy has potential to fabricate the practical superhydrophobic Cu 2 S@Cu 2 O film on copper surface on a large scale due to its simplicity and low cost.", "author_names": [ "Pihui Pi", "Kun Hou", "Cailong Zhou", "Li Guidong", "Xiufang Wen", "Shouping Xu", "Jiang Cheng", "Shuangfeng Wang" ], "corpus_id": 138891760, "doc_id": "138891760", "n_citations": 50, "n_key_citations": 0, "score": 0, "title": "Superhydrophobic Cu 2 S@Cu 2 O film on copper surface fabricated by a facile chemical bath deposition method and its application in oil water separation", "venue": "", "year": 2017 }, { "abstract": "Abstract Antimony sulfide (Sb 2 S 3 thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb 2 S 3 thin films produced by normal CBD and LACBD were analyzed by X Ray diffraction (XRD) Raman Spectroscopy, Atomic force microscopy (AFM) X Ray photoelectron spectroscopy (XPS) UV vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb 2 S 3 thin films for optoelectronic applications.", "author_names": [ "Sadasivan Shaji", "L V Garcia", "Shadai Lugo Loredo", "Bindu Krishnan", "J A Aguilar Martinez", "Tushar Kanti Das Roy", "David Avellaneda Avellaneda" ], "corpus_id": 99477396, "doc_id": "99477396", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "Antimony sulfide thin films prepared by laser assisted chemical bath deposition", "venue": "", "year": 2017 } ]

[ { "abstract": "A bottleneck limiting the widespread application of semiconductor nanocrystal solids is their poor conductivity. We report that the conductivity of thin films of n type CdSe nanocrystals increases by many orders of magnitude as the occupation of the first two electronic shells, 1Se and 1Pe, increases, either by potassium or electrochemical doping. Around half filling of the 1Se shell, a peak in the conductivity is observed, indicating shell to shell transport. Introducing conjugated ligands between nanocrystals increases the conductivities of these states to ~10 2 siemens per centimeter.", "author_names": [ "Dong Yu", "Congjun Wang", "Philippe Guyot-Sionnest" ], "corpus_id": 33819795, "doc_id": "33819795", "n_citations": 430, "n_key_citations": 6, "score": 1, "title": "n Type Conducting CdSe Nanocrystal Solids", "venue": "Science", "year": 2003 }, { "abstract": "We present a general synthesis for a family of n type transparent conducting oxide nanocrystals through doping with aliovalent cations. These monodisperse nanocrystals exhibit localized surface plasmon resonances tunable in the mid and near infrared with increasing dopant concentration. We employ a battery of electrical measurements to demonstrate that the plasmonic resonance in isolated particles is consistent with the electronic properties of oxide nanocrystal thin films. Hall and Seebeck measurements show that the particles form degenerately doped n type solids with free electron concentrations in the range of 1019 to 1021 cm 3. These heavily doped oxide nanocrystals are used as the building blocks of conductive, n type thin films with high visible light transparency.", "author_names": [ "Benjamin T Diroll", "Thomas R Gordon", "E Ashley Gaulding", "D R Klein", "Taejong Paik", "Hyeong Jin Yun", "E D Goodwin", "Divij Damodhar", "Cherie R Kagan", "Christopher B Murray" ], "corpus_id": 102321644, "doc_id": "102321644", "n_citations": 33, "n_key_citations": 1, "score": 0, "title": "Synthesis of N Type Plasmonic Oxide Nanocrystals and the Optical and Electrical Characterization of their Transparent Conducting Films", "venue": "", "year": 2014 }, { "abstract": "Thermoelectric materials, capable of converting heat directly into electricity without moving parts, provide a promising solid state solution for waste heat harvesting. However, currently available commercial thermoelectric materials PbTe and Bi2Te3 are based on tellurium, an extremely scarce and expensive element, which prohibits large scale applications. Herein, we present a systematic study on a new low cost Te free material, n type Se doped Mg3Sb1.5Bi0.5, by combining the structure and property characterization with electronic structure and electrical transport modeling. Compared with pure Mg3Sb2, Se doped Mg3Sb1.5Bi0.5 shows the considerably enhanced power factor as well as much lower thermal conductivity. The excellent electrical transport originates from a nontrivial near edge conduction band with six conducting carrier pockets and a light conductivity effective mass as well as the weak contribution from a secondary conduction band with a valley degeneracy of 2. The accurate location of the conduct.", "author_names": [ "Jiawei Zhang", "Lirong Song", "Aref H Mamakhel", "Mads Ry Vogel Jorgensen", "Bo Brummerstedt Iversen" ], "corpus_id": 98962688, "doc_id": "98962688", "n_citations": 80, "n_key_citations": 0, "score": 0, "title": "High Performance Low Cost n Type Se Doped Mg3Sb2 Based Zintl Compounds for Thermoelectric Application", "venue": "", "year": 2017 }, { "abstract": "We investigate the effects of stoichiometric imbalance on the electronic properties of lead chalcogenide nanocrystal films by introducing excess lead (Pb) or selenium (Se) through thermal evaporation. Hall effect and capacitance voltage measurements show that the carrier type, concentration, and Fermi level in nanocrystal solids may be precisely controlled through their stoichiometry. By manipulating only the stoichiometry of the nanocrystal solids, we engineer the characteristics of electronic and optoelectronic devices. Lead chalcogenide nanocrystal field effect transistors (FETs) are fabricated at room temperature to form ambipolar, unipolar n type, and unipolar p type semiconducting channels as prepared and with excess Pb and Se, respectively. Introducing excess Pb forms nanocrystal FETs with electron mobilities of 10 cm(2)(V s) which is an order of magnitude higher than previously reported in lead chalcogenide nanocrystal devices. Adding excess Se to semiconductor nanocrystal solids in PbSe Schottky solar cells enhances the power conversion efficiency.", "author_names": [ "Soong Ju Oh", "Nathaniel E Berry", "Ji-Hyuk Choi", "E Ashley Gaulding", "Taejong Paik", "Sung-Hoon Hong", "Christopher B Murray", "Cherie R Kagan" ], "corpus_id": 29808266, "doc_id": "29808266", "n_citations": 174, "n_key_citations": 4, "score": 0, "title": "Stoichiometric control of lead chalcogenide nanocrystal solids to enhance their electronic and optoelectronic device performance.", "venue": "ACS nano", "year": 2013 }, { "abstract": "line n Type CdS CdSe Electrodes,\" J. Electrochem. Soc. vol. 125 (1978) pp. 375 379. A. J. Strauss et al. \"Phase Diagram of the CdTe CdSe Pseudo Binary System,\" J. Electrochem. Soc, vol. 117, (1970) pp. 1420 1426. H. Tai et al. \"Optical Properties of (CdTe)(CdSe) and (CdTe) (CdS) Systems, Phys. Stat. Sol. (a) vol. 30, K115 K119 (1975) Berishvili et al. Poloprovodn Tekh Mikroelecktron, vol. 28, pp. 23 31 (1978) A. D. Stuckes, \"Electrical Thermal Properties of Alloys of CdTe and CdSe,\" J. Phys. Chem. Solids, vol. 25, pp. 477 482 (1964) Chem. Abstracts, vol. 77, 157719d (1972) Chem. Abstracts, vol. 87 110018r (1977)", "author_names": [ "Alloy Photovoltaic", "Mater Als", "Gary Hodes", "David Cahen" ], "corpus_id": 208137261, "doc_id": "208137261", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "United States Patent 19 Hodes et al 54 CD SE TE ALLOY PHOTOVOLTAIC", "venue": "", "year": 2017 }, { "abstract": "The temperature and electrical field dependent conductivity of n type CdSe nanocrystal thin films is investigated. In the low electrical field regime, the conductivity follows sigma approximately exp( (T(/T)(1/2) in the temperature range 10<T<120 K. At high electrical field, the conductivity is strongly field dependent. At 4 K, the conductance increases by 8 orders of magnitude over one decade of bias. At a very high field, conductivity is temperature independent with sigma approximately exp( (E(/E)(1/2) The complete behavior is very well described by variable range hopping with a Coulomb gap.", "author_names": [ "Dong Yu", "Congjun Wang", "Brian L Wehrenberg", "Philippe Guyot-Sionnest" ], "corpus_id": 10565090, "doc_id": "10565090", "n_citations": 296, "n_key_citations": 5, "score": 0, "title": "Variable range hopping conduction in semiconductor nanocrystal solids.", "venue": "Physical review letters", "year": 2004 }, { "abstract": "Colloidal semiconductor nanocrystals have emerged as fascinating new materials and gained interest in the last 30 years because of their size, shape, and compositionally tunable electronic and optical properties as well as their potential to serve as artificial atoms. Challenges and opportunities have arisen when assembling nanocrystals into nanocrystal solids for electronic and optoelectronic applications, largely because of the significant influence of nanocrystal surface chemistry on the electronic, optical, and structural properties of nanocrystal solids. In order to assemble nanocrystal solids for high performance devices, we must understand and be able to control the effects of nanocrystal surface organic capping ligands, non stoichiometry, and impurity doping on the electronic and optoelectronic properties of the nanocrystal solids. Here, we show that exposing CdSe nanocrystals to methanol removes oleic acid capping ligands and/or Cd ions from the nanocrystal surface, introducing mid band gap trap states that are recombination centers for photogenerated electron/hole pairs. Using photoluminescence spectroscopy and photoconductivity measurements we illustrate that these trap states have the adverse effects of decreased photoluminescence quantum yield and lifetime and decreased photoconductivity. Treatment with CdCl2 fills these traps states, realizing a significant increase in photocurrent magnitude and lifetime. We present examples of intentional nanocrystal surface chemical modifications: non stoichiometry doping of PbSe nanocrystals by surface enrichment with excess Pb or Se, and surface impurity doping and passivation of CdSe nanocrystals by thermal diffusion of indium. We demonstrate how these modifications shift the Fermi level of the PbSe or CdSe nanocrystal solid through the density of electronic states of the valence band (PbSe nanocrystal solid only) mid gap, and the conduction band. Using field effect transistor and flash photolysis time resolved microwave conductivity measurements we show that control of the Fermi level can be used to effectively tailor the charge carrier polarity (PbSe nanocrystal solid only) mobility, and lifetime. We find that Se rich PbSe and non indium treated CdSe nanocrystals have a greater tendency to fuse with nearest neighbor nanocrystals than do Pb rich PbSe and indium treated CdSe nanocrystals. Finally, we present a flexible, robust method for assembling nanocrystals into high quality, ordered (in some cases superlattices) uniform nanocrystal solids for application in electronic and optoelectronic devices. Degree Type Dissertation Degree Name Doctor of Philosophy (PhD) Graduate Group Chemistry First Advisor Cherie R. Kagan This dissertation is available at ScholarlyCommons: http:/repository.upenn.edu/edissertations/1744 Second Advisor Christopher B. Murray", "author_names": [ "E D Goodwin" ], "corpus_id": 137857445, "doc_id": "137857445", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The optoelectronic properties of surface modified semiconductor nanocrystal solids", "venue": "", "year": 2015 }, { "abstract": "Abstract Herein, we introduce a unique nanomaterial chemical transformation (NCT) process whereby selenium (Se) anion is introduced to colloidal silver (Ag) nanocrystals (NCs) to create nanostructured silver selenide (Ag2Se) We present a complete suite of material characterizations, including chemical, structural, optical, and electrical characterizations to understand the details of the transformation process. The Ag2Se thin films obtained through the NCT process exhibit degenerately doped n type semiconductor characteristics with high carrier mobility. We discuss the chemical mechanism that drives the material transformation and elucidates the origin of doping in these semiconducting thin films. We also demonstrate the robustness of Ag2Se thin films toward mechanical strain and temperature cycling stress for flexible device applications. We believed that the NCT process demonstrated here is of wide applicability to other material systems which can open up new avenues for solid state chemistry and device engineering research.", "author_names": [ "Sanghyun Jeon", "Junhyuk Ahn", "Junsung Bang", "Ho Kun Woo", "Shihab Bin Hafiz", "Dong-Kyun Ko", "Soong Ju Oh" ], "corpus_id": 214546584, "doc_id": "214546584", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Property engineering through nanomaterial chemical transformation of colloidal nanocrystal thin films", "venue": "", "year": 2020 }, { "abstract": "CdSe is an important compound semiconducting material for the development of various applications in solid state devices such as solar cells, high efficiency thin film transistors. In recent years major attention has been given to the investigation of structural and electrical properties for the improvement of performance of such devices and its applications[1] We prepared n type CdSe thin films on glass substrate using cadmium selenide material with various composition of Cd (99.999% and Se (99.999% by electron beam evaporation technique under vacuum 10 5 torr in vacuum coating unit, keep substrates at room temperature and studied the effect of composition ratio of cadmium selenium on thin films and evaluate the grain size, resistivity, hallmobility and carrier concentration in n type CdSe thin films.", "author_names": [ "A K Verma", "S R Vishwakarma", "R S N Tripathi", "" ], "corpus_id": 55705725, "doc_id": "55705725", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effect of deposition parameter on structural and electrical properties of n type cadmium selenide thin films", "venue": "", "year": 2011 }, { "abstract": "In the present investigation, polycrystalline semiconductor Cd Se Te films have been electrodeposited at room temperature on conducting glass substrates using cyclic voltammetric technique under controlled periodic scans. The successive anodic and cathodic scans were recorded within the potential range, from 0 to 1.0 V, and over the range of periodic cycles, from 250 to 2,000, in an acidic bath containing respective reducible precursor ions like Cd2+ Se4+ Te4+ and 1 vol. Triton X 100 as the surface active reagent. Thin composite films were produced having variable thickness and composition and grain size of the order of 80 100 nm. The film properties were determined by focused ion beam analysis, energy dispersive analysis of x rays, x ray diffraction studies, atomic force microscopy, and scanning electron microscopy. Thickness of the semiconductor films was found to increase linearly with the number of voltammetric cycles. Band gap energies of the films as derived from the reflectance spectra were found to lie between 1.4 and 1.7 eV. The composite films of the Cd Se Te ternary system when electrochemically characterized in aqueous polysulfide solution exhibited n type semiconducting properties and photoconversion efficiency more than 0.4%", "author_names": [ "Chinmoy Bhattacharya", "Jayati Datta" ], "corpus_id": 94734223, "doc_id": "94734223", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Synthesis of nanostructured Cd Se Te films through periodic voltammetry for photoelectrochemical applications", "venue": "", "year": 2006 } ]

[ { "abstract": "Lithium rich phosphides have recently attracted considerable attention due to their potential application as high capacity and high rate anodes for lithium ion batteries (LIBs) However, there is still short of the promising candidate thus far because of the poor electrical conductivity or huge volume change in the already known Li P compounds. In this work, we report two novel Li P states, Li5P2 and Li4P, stabilized under high pressures that are predicted to be quenchable down to ambient conditions by first principles swarm structure calculations. The predicted P3m1 Li5P2 shows interesting features as a p type semiconductor with an indirect band gap of 0.787 eV, possessing significant anisotropy properties in electrical transport, while R3[combining macron]m Li4P acts as a typical electride with metallic behavior at pressures of 0 82 GPa. More importantly, our calculations reveal that the theoretical capacities of Li5P2 and Li4P are predicted to reach 2164 and 3462 mA h g 1, respectively. Combined with the good electrical transport properties, the calculated volume expansion of Li5P2 (130% is found to be much smaller than those of the previously reported Li P compounds, indicating its potential as a high performance anode material for LIBs.", "author_names": [ "Ge Fei", "Shuai Duan", "Mingxing Zhang", "Zebin Ren", "Yangfan Cui", "Xin-Yu Chen", "Yunxian Liu", "Wencai Yi", "Xiaobing Liu" ], "corpus_id": 221181535, "doc_id": "221181535", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Predicted stable Li5P2 and Li4P at ambient pressure: novel high performance anodes for lithium ion batteries.", "venue": "Physical chemistry chemical physics PCCP", "year": 2020 }, { "abstract": "Metallic lithium, which is a negative electrode for Li ion batteries with one of the highest specific capacities and lowest voltage, has not reached yet the commercial stage in rechargeable batteries because of safety issues related to instabilities arising on the Li surface during electrochemical cycling [1] When metallic lithium is in contact with the battery electrolyte, a surface layer called SEI (Solid Electrolyte Interface) is formed owing to the electrochemical instability of the electrolyte at low voltages. In a conventional Li ion battery with graphite based anode, the SEI layer is a passivation interface that will help to stabilize the battery in exchange of some irreversible capacity loss. However, when considering Li metal anodes, although some interesting approaches with special salts have been reported [2] the conventional SEI is unable to maintain a uniform plating and stripping of Li during battery operation [3] In order to find a suitable solution for the stabilization of the lithium surface, it is essential to have a full understanding of the nature and characteristics of its high reactivity. For this purpose, one of the preliminary steps is to analyze the effects that atmospheric gases present in the dry room environment where Li ion batteries are processed, have on the surface of Li metal. Ambient Pressure X Ray Photoelectron Spectroscopy (APXPS) is an ideal tool to explore this phenomenon. Our recent studies done in the APXPS from beamline 9.3.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory (California, United States) provide key insight in the reaction mechanism behind the formation of lithium carbonate, one of the main components of conventional SEI layers, when this metal is exposed to CO2 gas, as can be seen in Figure 1.", "author_names": [ "Ane Etxebarria", "Monika Blum", "Pinar Aydogan Gokturk", "Dong-Jin Yun", "Ethan J Crumlin", "Miguel A Munoz-Marquez" ], "corpus_id": 221138226, "doc_id": "221138226", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Study of the reaction mechanisms of dry room gases on metallic lithium anodes for Li ion batteries using in situ ambient pressure X ray photoelectron spectroscopy", "venue": "", "year": 2019 }, { "abstract": "", "author_names": [ "Mingyi Chen", "Jiahao Liu", "Dongxu Ouyang", "Jui-ying Wang" ], "corpus_id": 195390263, "doc_id": "195390263", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Experimental investigation on the effect of ambient pressure on thermal runaway and fire behaviors of lithium ion batteries", "venue": "International Journal of Energy Research", "year": 2019 }, { "abstract": "", "author_names": [ "Julia Maibach" ], "corpus_id": 214211858, "doc_id": "214211858", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Lithium ion batteries studied with ambient pressure photoelectron spectroscopy", "venue": "", "year": 2019 }, { "abstract": "Abstract The fire and explosion risks of lithium ion batteries (LIBs) pose serious threat to the transport and application of LIBs on the aircraft. Therefore, the study of corresponding thermal safety problems in flight condition is of great importance. In this work, a dynamic pressure chamber is used to study the effect of cycling aging and ambient pressure on the thermal safety features of LIBs. The results show that both the thermal runaway onset time and temperature decrease with the increase of cycle number or decrease of external pressure. The interval time between gas release and ignition decreases with the increase of cycle number, while the burning time increases with the decrease of pressure. Moreover, the thermal runaway temperature and heat release rate decrease with the increase of cycle number or decrease of pressure. The dV/dQ and X ray computed tomography results show that the loss and structural damage of cathode materials, and the side reactions are the main factors for the decrease of battery safety. The easier occurrence of thermal runaway in low pressure is attributed to the larger differential pressure which facilitates the opening of burst disk and the entry of air.", "author_names": [ "Lixiang Ren", "Xiaoyong Yang", "Xiantao Chen", "Yuanhua He" ], "corpus_id": 209710430, "doc_id": "209710430", "n_citations": 13, "n_key_citations": 0, "score": 1, "title": "Influence of cycling aging and ambient pressure on the thermal safety features of lithium ion battery", "venue": "", "year": 2020 }, { "abstract": "When lithium ion batteries (LIBs) are located at high altitude and low pressure,the characteristics of thermal runaway (TR) and its propagation are different,such as time to TR, the toxicity of TR gases, TR propagation time, mass loss rate, etc. In this article, the author summarized a series of relevant literatures and proposed an instrument that can be used to analyse the TR behavior at different pressure. It is found that: with the decrease of ambient pressure, the TR trigger time becomes longer and the maximum surface temperature decrease. Moreover, the gas released by TR becomes more toxic as the environmental pressure decreases. Beside, the average propagation time between adjacent LIBs is not much difference when the environmental pressure decreases, and when the 18,650 battery module is distributed in a cylindrical shape, the thermal runaway propagation path is basically unchanged as the environmental pressure decreases. This work details TR and its propagation feature under different pressure, and can provide the guidelines for the Air transportation of LIBs.", "author_names": [ "Huai-bin Wang", "Zhiming Du", "Ling Liu", "Ze-lin Zhang", "Jinyuan Hao", "Qinzheng Wang", "Shuang Wang" ], "corpus_id": 212815439, "doc_id": "212815439", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Study on the Thermal Runaway and Its Propagation of Lithium Ion Batteries Under Low Pressure", "venue": "", "year": 2020 }, { "abstract": "DOI: 10.1002/aenm.201900454 Today's lithium ion batteries (LIBs) can offer high energy density (260 Wh kg 1 and 700 Wh L 1 at cell level) and high Coulombic efficiency (99.98% and long cycling life >1000 cycles) making them the dominating power sources for portable electronics and electric vehicles (EVs)[1,2] Due to With the rapid growth of the lithium ion battery (LIBs) market, recycling and re use of end of life LIBs to reclaim lithium (Li) and transition metal (TM) resources (e.g. Co, Ni) as well as eliminating pollution from disposal of waste batteries, has become an urgent task. Here, for the first time the ambient pressure relithiation of degraded LiNi0.5Co0.2Mn0.3O2 (NCM523) cathodes via eutectic Li+ molten salt solutions is successfully demonstrated. Combining such a low temperature relithiation process with a well designed thermal annealing step, NCM523 cathode particles with significant Li loss (40% and capacity degradation (50% can be successfully regenerated to achieve their original composition and crystal structures, leading to effective recovery of their capacity, cycling stability, and rate capability to the levels of the pristine materials. Advanced characterization tools including atomic resolution electron microscopy imaging and electron energy loss spectroscopy are combined to demonstrate that NCM523's original layered crystal structure is recovered. For the first time, it is shown that layer to rock salt phase change on the surfaces and subsurfaces of the cathode materials can be reversed if lithium can be incorporated back to the material. The result suggests the great promise of using eutectic Li+ molten salt solutions for ambient pressure relithiation to recycle and remanufacture degraded LIB cathode materials.", "author_names": [ "Yang Shi", "Minghao Zhang", "Ying Shirley Meng", "Zheng Chen" ], "corpus_id": 145826276, "doc_id": "145826276", "n_citations": 41, "n_key_citations": 0, "score": 0, "title": "Ambient Pressure Relithiation of Degraded Li x Ni 0.5 Co 0.2 Mn 0.3 O 2 (0 x 1) via Eutectic Solutions for Direct Regeneration of Lithium Ion Battery Cathodes", "venue": "Advanced Energy Materials", "year": 2019 }, { "abstract": "Black phosphorus, the result of white P under high pressure, has received much attention as a promising anode material for Li ion batteries (LIBs) However, the final product of lithiation, P63/mmc Li3P, is not satisfactory due to its poor conductivity. In this article we explore the high pressure phase diagram of the Li P system through first principles swarm intelligence structural search and present two hitherto unknown stable Li rich compounds, Fm 3m Li3P at 4.2 GPa and P6/mmm Li5P at 10.3 GPa. Metallic Li5P exhibits interesting structural features, including graphene like Li layers and P centered octadecahedrons, where P is 14 fold coordinated with Li. Interestingly, both compounds exhibit good dynamical and thermal stability properties at ambient pressure, and the theoretical capacity of P6/mmm Li5P reaches 4326 mAhg 1, the highest among the already known Li P compounds. Additionally, their mechanical properties are also favorable for electrode materials. Our work represents a significant step towar.", "author_names": [ "Ziyuan Zhao", "Lulu Liu", "Tong Yu", "Guochun Yang", "Aitor Bergara" ], "corpus_id": 102646309, "doc_id": "102646309", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Pressure Induced Stable Li5P for High Performance Lithium Ion Batteries", "venue": "", "year": 2017 }, { "abstract": "A carbon nanotubes/graphene composite is grown on nickel foil without additional catalysts by one step ambient pressure chemical vapor deposition (CVD) Next, the carbon nanotubes/graphene composite is modified by radio frequency (RF) nitrogen plasma. Finally, to improve its initial coulombic efficiency/electrochemical stability, lower potential during the charge process (coin cell) and boost potential during the discharge process (lithium ion battery) alumina is deposited onto the N doped carbon nanotubes/graphene composite by RF magnetron sputtering at different power levels and periods of time. The charge specific capacity (597 mAh/g) and initial coulombic efficiency (81.44% 75.02% for N doped carbon nanotubes/graphene) of Al2O3/N doped CNTs/graphene for the coin cell reached a maximum at the best sputtering condition and Al2O3/N doped CNTs/graphene (the best sputtering condition) exhibits higher initial coulombic efficiency (79.8% compared with N doped CNTs/graphene (initial coulombic efficiency: 74.3% for the lithium ion battery. Furthermore, the achievement fraction (about 70% of full charge capacity (coin cell) for Al2O3/N doped carbon nanotubes/graphene (the best sputtering condition) is higher than that (about 30% for N doped carbon nanotubes/graphene at a voltage lower than about 0.25 V. Moreover, it also shows a little higher electrochemical stability (coin cell) of charge capacity for Al2O3/N doped carbon nanotubes/graphene (the best sputtering condition) in comparison with N doped carbon nanotubes/graphene and Al2O3/N doped CNTs/graphene (the best sputtering condition) exhibits better cyclic stability (lithium ion battery) of discharge capacity compared with N doped CNTs/graphene.", "author_names": [ "Chuen-Chang Lin", "Shu-Pei Hsu", "Guang-Jhong Chen" ], "corpus_id": 229455405, "doc_id": "229455405", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effects of Alumina Films on N Doped Carbon Nanotubes/Graphene Composites as Anode Materials of Lithium Ion Batteries", "venue": "", "year": 2020 }, { "abstract": "Three groups of 18 65 cylindrical lithium ion cells with different positive active materials (NCA nickel cobalt aluminium, NMC nickel manganese cobalt, LFP lithium iron phosphate) and electrode designs (high power, high energy) were tested using an accelerated low earth orbit (LEO) CubeSat power profile cycle. Each design yields a unique energy density, power capability and cycle life. Each cell type was tested in a 3P group configuration at 10 degC under hard vacuum ~0.2 kPa) and atmospheric pressure ~101 kPa) Cells groups were operated in their respective ambient condition until they failed to successfully execute the accelerated LEO cycle. In atmospheric and vacuum pressure, both NMC groups failed due to internal resistance growth. The atmospheric pressure NCA group failed due to excessive internal gas build up causing the CID (current interrupt device) The NCA group in vacuum pressure has completed approximately 2,680 orbits or 505 equivalent 100% DSoC cycles and is still operational showing 25% capacity degradation from its initial capacity. The LFP groups both in vacuum and atmospheric pressure have completed approximately 2,680 orbits or 1,730 equivalent 100% DSoC cycles and are still operational with both showing 13% capacity degradation from their initial capacity.", "author_names": [ "Riley Cook", "Lukas Swan" ], "corpus_id": 225305185, "doc_id": "225305185", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Experimental Analysis of Lithium Ion Batteries for Low Earth Orbit CubeSat Applications", "venue": "", "year": 2020 } ]

[ { "abstract": "Abstract Hollow heterostructured g C3N4@CeO2 photocatalysts with rich oxygen vacancies are controllable designed by a facile strategy. The synergetic effect and oxygen vacancies of g C3N4@CeO2 play the major role in the process of CO2 reduction, leading to CH4 generating much earlier and higher concentration than that of the pristine g C3N4 and CeO2 alone. Meanwhile, the unique hollow structures can make multiple reflections of light in the cavity, and thus enhance the utilization efficiency of light. Moreover, the L cysteine offers amine groups and meanwhile is anchored on the surface of g C3N4 during the synthesis process, and thus contributes greatly to the enhanced CO2 adsorption capability. Additionally, the large CO2 adsorption capability is also beneficial for the enhanced photocatalytic activity. Therefore, the novel photocatalysts exhibit a remarkable reduction performance for CO2 reduction under visible light irradiation. The g C3N4@CeO2 (CeO2 49.7 wt shows the highest yields of CH4 (3.5 mmol g 1) CH3OH (5.2 mmol g 1) and CO (16.8 mmol g 1) which are higher than most of other latest reported g C3N4 based photocatalysts for CO2 photoreduction, including coupled with semiconductors and noble metal cocatalysts. This strategy might represent a novel way for the effective conversion of CO2 to clean fuels and can also be great potential used in the energy and environmental science.", "author_names": [ "Mengfang Liang", "Timur Borjigin", "Yuhao Zhang", "Beihong Liu", "Hui Liu", "Hong Guo" ], "corpus_id": 105843000, "doc_id": "105843000", "n_citations": 128, "n_key_citations": 1, "score": 0, "title": "Controlled assemble of hollow heterostructured g C3N4@CeO2 with rich oxygen vacancies for enhanced photocatalytic CO2 reduction", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Abstract Organic pollutants' treatment in wastewater has attracted extensive attention due to its degradation resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2 based solid solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2 based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.", "author_names": [ "Ran Ma", "Sai Zhang", "Tao Wen", "Pengcheng Gu", "Lei Li", "Guixia Zhao", "Fenlei Niu", "Qifei Huang", "Zhenwu Tang", "Xiangke Wang" ], "corpus_id": 104298969, "doc_id": "104298969", "n_citations": 114, "n_key_citations": 0, "score": 0, "title": "A critical review on visible light response CeO2 based photocatalysts with enhanced photooxidation of organic pollutants", "venue": "Catalysis Today", "year": 2019 }, { "abstract": "Highly efficient photocatalysts are urgently needed with the ever increasing problems of environmental pollution and the energy crisis. Herein, we report a shape controlled binary photocatalyst consisting of S doped CeO2 hollow spheres sensitized with ultrathin CdS shells. The core shelled CeO2 xSx@CdS composite is synthesized using a simple template assisted method followed by anion exchange and chemical bath deposition processes. Owing to the reduced band gap caused by the oxygen vacancies in the S doped CeO2, and the CdS sensitization effect accelerating the interface carrier separation and transfer, the CeO2 xSx@CdS composite exhibits superior photocatalytic activity for hydrogen evolution (1147.2 mmol g 1 h 1) under visible light illumination, which is 4.4, 11.1 and 94.8 times higher than that of CdS (258.2 mmol g 1 h 1) CeO2 xSx (103.0 mmol g 1 h 1) and CeO2 (12.1 mmol g 1 h 1) respectively. In addition, the composite displays highly efficient organic pollutant degradation (99.8% degradation of RhB within 25 min)", "author_names": [ "Ningchao Zheng", "Ting Ouyang", "Yibo Chen", "Zhu Wang", "Di-yun Chen", "Zhao-Qing Liu" ], "corpus_id": 104391444, "doc_id": "104391444", "n_citations": 109, "n_key_citations": 0, "score": 0, "title": "Ultrathin CdS shell sensitized hollow S doped CeO2 spheres for efficient visible light photocatalysis", "venue": "", "year": 2019 }, { "abstract": "Abstract Pd/CeO2 is an active component in emission control catalysts for CO oxidation. Nanostructured CeO2 powders can be prepared in the form of rods exposing predominantly (111) surfaces and cubes exposing (100) surfaces. While differences in the reactivity of Pd supported on these facets of ceria have been reported, the origins of the reactivity differences are not well understood. Pd supported on (111) surfaces of ceria rods exhibits room temperature CO oxidation activity, while Pd on (100) surface of ceria cubes shows comparable activity at a temperature that is 60 degC higher. Earlier, we established that Pd/CeO2 rods are active due to a Langmuir Hinshelwood mechanism involving isolated Pd atoms in the form of Pd1O and Pd1O2 species. Here, we establish using in situ CO IR spectroscopy and density functional theory (DFT) that, in addition to TEM visible Pd nanoparticles, Pd/CeO2 cubes also contain isolated Pd species, predominantly in the form of Pd1O. DFT calculations show that CO oxidation proceeds via a Mars van Krevelen pathway, which is possible for the (100) surface because of the lower Ce O binding energy compared to the (111) surface. Overall, the catalytic cycle for CO oxidation on Pd/CeO2(100) involves a higher free energy barrier than on Pd/CeO2(111) in keeping with the experimentally observed activity difference. EXAFS measurements show that the active Pd phase in both Pd/CeO2 rods and Pd/CeO2 cubes responds dynamically with respect to reducing and oxidizing conditions. The redispersion of Pd in oxidative conditions is more pronounced for Pd/CeO2 rods and the catalyst is more active after an oxidative treatment.", "author_names": [ "Giulia Spezzati", "Angelica Benavidez", "Andrew DeLaRiva", "Yaqiong Su", "Jan Philipp Hofmann", "Shunsuke Asahina", "E J Olivier", "Johannes H Neethling", "Jeffrey T Miller", "Abhaya K Datye", "Emiel J M Hensen" ], "corpus_id": 104834335, "doc_id": "104834335", "n_citations": 99, "n_key_citations": 0, "score": 0, "title": "CO oxidation by Pd supported on CeO2(100) and CeO2(111) facets", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Stable catalysts through steaming The lifetime of catalysts that convert automotive exhaust pollutants can be increased by lowering their operating temperature, which helps to prevent deactivation caused by the active metal atoms agglomerating into larger, less active particles. Nie et al. show that a thermally stable catalyst, atomically dispersed Pt2+ on CeO2, can become active for CO oxidation at 150degC after steam treatment at 750degC. In studies with simulated vehicle exhaust, this catalyst treatment also improves its oxidation activity for other exhaust components such as hydrocarbons. Science, this issue p. 1419 Steam treatment at 750degC transforms single Pt2+ ions on CeO2 into a CO oxidation catalyst active at low temperatures. To improve fuel efficiency, advanced combustion engines are being designed to minimize the amount of heat wasted in the exhaust. Hence, future generations of catalysts must perform at temperatures that are 100degC lower than current exhaust treatment catalysts. Achieving low temperature activity, while surviving the harsh conditions encountered at high engine loads, remains a formidable challenge. In this study, we demonstrate how atomically dispersed ionic platinum (Pt2+ on ceria (CeO2) which is already thermally stable, can be activated via steam treatment (at 750degC) to simultaneously achieve the goals of low temperature carbon monoxide (CO) oxidation activity while providing outstanding hydrothermal stability. A new type of active site is created on CeO2 in the vicinity of Pt2+ which provides the improved reactivity. These active sites are stable up to 800degC in oxidizing environments.", "author_names": [ "Lei Nie", "Donghai Mei", "Haifeng Xiong", "Boaxing Peng", "Zhibo Ren", "Xavier Isidro Pereira Hernandez", "Andrew DeLaRiva", "Meng Wang", "Mark H Engelhard", "Libor Kovarik", "Abhaya K Datye" ], "corpus_id": 206662589, "doc_id": "206662589", "n_citations": 537, "n_key_citations": 1, "score": 0, "title": "Activation of surface lattice oxygen in single atom Pt/CeO2 for low temperature CO oxidation", "venue": "Science", "year": 2017 }, { "abstract": "Abstract Ceria (CeO2) with abundant oxygen defects, surface alkalinity, low cost effectiveness and admirable redox ability could be used in the photoreduction of CO2. However, little attention has been paid to the interaction of reactant CO2 molecules on CeO2 based photocatalysts. In this work, Cu2O nanoparticles were applied to the modification of the properties of Lewis acid/base, surface oxygen defect content and visible light adsorption of CeO2, and the adsorption/activation abilities of CO2 reactant on Cu2O/CeO2 and CeO2 photocatalysts were investigated in comparison. The photocatalytic performance showed that Cu2O/CeO2 had better activity than CeO2. And the loading of Cu2O resulted in more oxygen defects and Ce3+ species, which was helpful for available visible light adsorption and higher charge separation efficiency. Furthermore, CO2 TPD, CO2 adsorption DRIFTS and in situ ESR results demonstrated that the synergistic effects of Cu2O/CeO2 were beneficial for more generated carboxylate and CO2 radicals, instead of carbonate species which promoted CO2 reduction to CO.", "author_names": [ "Yu Pu", "Yidan Luo", "Xiaoqian Wei", "Jingfang Sun", "Lulu Li", "Weixin Zou", "Lin Dong" ], "corpus_id": 155349363, "doc_id": "155349363", "n_citations": 76, "n_key_citations": 0, "score": 0, "title": "Synergistic effects of Cu2O decorated CeO2 on photocatalytic CO2 reduction: Surface Lewis acid/base and oxygen defect", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Here, we report the synthesis of Cu doped CeO2 nanorods (denoted as Cu CeO2 x, x represents the mass content (wt% of the doped Cu) by a facile hydrothermal method, followed by thermal treatment in an H2/Ar atmosphere. As the electrocatalyst, Cu CeO2 3.9 with a large surface area of 95.2 m2 g 1 and mesoporous structure exhibits high electrocatalytic activity toward the N2 reduction reaction (NRR) delivering an NH3 yield rate of 5.3 x 10 10 mol s 1 cm 2 and a faradaic efficiency of 19.1% at 0.45 V (vs. RHE) in a 0.1 M Na2SO4 electrolyte (pH 6.3) much higher than the NRR performance achieved with pure CeO2 nanorods. The Cu doping can effectively tune the concentration of multiple oxygen vacancies in CeO2, thus resulting in significantly improved NRR activity.", "author_names": [ "Shengbo Zhang", "Cuijiao Zhao", "Yanyan Liu", "Wenyi Li", "Jialu Wang", "Guozhong Wang", "Yunxia Zhang", "Haimin Zhang", "Huijun Zhao" ], "corpus_id": 206140100, "doc_id": "206140100", "n_citations": 67, "n_key_citations": 0, "score": 0, "title": "Cu doping in CeO2 to form multiple oxygen vacancies for dramatically enhanced ambient N2 reduction performance.", "venue": "Chemical communications", "year": 2019 }, { "abstract": "Abstract Manipulating interfacial structure and interaction between metal and supports is important for many heterogenous catalysts with the aim at achieving high and stable activity and selectivity. In this work, two kinds of Ni/CeO2 SiO2 catalysts are fabricated and designed, including CeO2 close contact with Ni nanoparticles (Ni/CeO2 SiO2 P) or CeO2 away from Ni nanoparticles (Ni/CeO2 SiO2 C) for dry reforming of methane. Ni/CeO2 SiO2 P exhibits superior low temperature activity and H2/CO ratio compared with Ni/CeO2 SiO2 C. CO2 and CH4 conversions on the former (87.3% and 78.5% are higher than those of the later (80.5% and 67.8% at 700 degC. Meanwhile, Ni/CeO2 SiO2 P is stable in the long term study whereas Ni/CeO2 SiO2 C presents poor stability and the activity dramatically decreases in 10 h. The improved performance and stability on Ni/CeO2 SiO2 P originates from more reactive oxygen species and more accessible sites for the formate species on the metal support interface. The reaction order and activation energy of both catalysts are also calculated in the kinetic studies. This work opens up new possibilities for exploring the effect of metal support on designing highly efficient heterogeneous catalysts.", "author_names": [ "Xiaoliang Yan", "Tong Hu", "Peng Liu", "Sha Sha Li", "Binran Zhao", "Qian Zhang", "Wei Jiao", "Shuai Chen", "Pengfei Wang", "Jingjun Lu", "Xiaonan Deng", "Yun-Xiang Pan" ], "corpus_id": 104351149, "doc_id": "104351149", "n_citations": 76, "n_key_citations": 0, "score": 0, "title": "Highly efficient and stable Ni/CeO2 SiO2 catalyst for dry reforming of methane: Effect of interfacial structure of Ni/CeO2 on SiO2", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Electrocatalytic oxygen evolution reaction (OER) is a key process in electrochemical energy conversion and storage. Cobalt containing spinel oxides are promising candidates for OER, but suffer from.", "author_names": [ "Bocheng Qiu", "Cong Wang", "Ning Zhang", "Lejuan Cai", "Yujie Xiong", "Yang Chai" ], "corpus_id": 196858265, "doc_id": "196858265", "n_citations": 90, "n_key_citations": 1, "score": 0, "title": "CeO2 Induced Interfacial Co2+ Octahedral Sites and Oxygen Vacancies for Water Oxidation", "venue": "ACS Catalysis", "year": 2019 }, { "abstract": "Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40(th) anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three way catalysts (TWCs) Apart from this well established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2 based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2 based materials has already been acquired, new characterization techniques and powerful theoretical methods are deepening our understanding of these materials, helping us to predict their behavior and application potential. This review has a wide view on all those aspects related to ceria which promise to produce an important impact on our life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.", "author_names": [ "Tiziano Montini", "Michele Melchionna", "Matteo Monai", "Paolo Fornasiero" ], "corpus_id": 206535172, "doc_id": "206535172", "n_citations": 1036, "n_key_citations": 5, "score": 1, "title": "Fundamentals and Catalytic Applications of CeO2 Based Materials.", "venue": "Chemical reviews", "year": 2016 } ]

[ { "abstract": "Reversible Implants Silicon electronics are generally designed to be stable and robust it would be counterproductive if the key parts of your computer or cell phone slowly dissolved away while you were using it. In order to develop transient electronics for use as medical implants, Hwang et al. (p. 1640, see the cover) produced a complete set of tools and materials that would be needed to make standard devices. Devices were designed to have a specific lifetime, after which the component materials, such as porous silicon and silk, would be resorbed by the body. A platform of materials and fabrication methods furnishes resorbable electronic devices for in vivo use. A remarkable feature of modern silicon electronics is its ability to remain physically invariant, almost indefinitely for practical purposes. Although this characteristic is a hallmark of applications of integrated circuits that exist today, there might be opportunities for systems that offer the opposite behavior, such as implantable devices that function for medically useful time frames but then completely disappear via resorption by the body. We report a set of materials, manufacturing schemes, device components, and theoretical design tools for a silicon based complementary metal oxide semiconductor (CMOS) technology that has this type of transient behavior, together with integrated sensors, actuators, power supply systems, and wireless control strategies. An implantable transient device that acts as a programmable nonantibiotic bacteriocide provides a system level example.", "author_names": [ "Suk-Won Hwang", "Hu Tao", "Dae-Hyeong Kim", "Huanyu Cheng", "Jun-Kyul Song", "Elliott Rill", "Mark A Brenckle", "Bruce J B Panilaitis", "Sang Min Won", "Yun-Soung Kim", "Young Min Song", "Ki Jun Yu", "Abid Ameen", "Rui Li", "Yewang Su", "Miaomiao Yang", "David Lee Kaplan", "Mitchell R Zakin", "Marvin J Slepian", "Yonggang Huang", "Fiorenzo G Omenetto", "John A Rogers" ], "corpus_id": 14319558, "doc_id": "14319558", "n_citations": 811, "n_key_citations": 10, "score": 1, "title": "A Physically Transient Form of Silicon Electronics", "venue": "Science", "year": 2012 }, { "abstract": "A remarkable feature of modern silicon electronics is its ability to remain functionally and physically invariant, almost indefinitely for many practical purposes. Here, we introduce a siliconbased technology that offers the opposite behavior: it gradually vanishes over time, in a wellcontrolled, programmed manner. Devices that are 'transient' in this sense create application possibilities that cannot be addressed with conventional electronics, such as active implants that exist for medically useful timeframes, but then completely dissolve and disappear via resorption by the body. We report a comprehensive set of materials, manufacturing schemes, device components and theoretical design tools for a complementary metal oxide semiconductor (CMOS) electronics of this type, together with four different classes of sensors and actuators in addressable To whom correspondence should be addressed. [email protected]; [email protected]. *These authors contributed equally to this work. Supplementary Information is linked to the online version of the paper at www.nature.com/nature. Author Contributions S. W.H. H.T. D. H.K. F.G.O. J.A.R. designed the experiments; S. W.H. H.T. D. H.K. H.C. J. K.S. E.R. M.B. S. M.W. Y. S.K. K. J.Y. A.A. R. L. Y. S. Y.H. F.G.O. J.A.R. performed experiments and analyses; S. W.H. H.T. D.H.K. H.C. Y.H. F.G.O. J.A.R. wrote the paper. Competing Interests statement The authors declare that they have no competing financial interest. NIH Public Access Author Manuscript Science. Author manuscript; available in PMC 2013 September 30. Published in final edited form as: Science. 2012 September 28; 337(6102) 1640 1644. doi:10.1126/science.1226325. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript arrays, two options for power supply and a wireless control strategy. A transient silicon device capable of delivering thermal therapy in an implantable mode and its demonstration in animal models illustrate a system level example of this technology. An overarching goal in the development of nearly any new class of electronics is to achieve high performance operation in physical forms that undergo negligible change with time. Active and passive materials, device and circuit layouts and packaging strategies are each carefully formulated individually and then configured collectively to accomplish this outcome. The transient electronics technology introduced here involves similar attention to engineering design, but in the context of systems that physically disappear, in whole or in part, at prescribed times and with well defined rates. Use scenarios range from integration with living hosts (human/animal/insect/plant; on dwelling or in dwelling) to indoor/outdoor environments such as buildings, roadways or materiel. Enabled devices include medical monitors that fully resorb when implanted into the human body \"bio resorbable\" to avoid adverse long term effects, or communications systems that dissolve when exposed to water \"eco resorbable\" to prevent unwanted discovery. Other concepts involve circuits that incorporate strategic regions with timed transience, to affect controlled transformation in function. In this following, we present (1) a complete collection of transient electronic building blocks, including nand p channel silicon nanomembrane (NM) metal oxide field effect transistors (MOSFETs) and their integration into circuits that disappear or functionally transform, (2) sensors of light, temperature and strain, each of which uses functional materials and formats common to those for the electronics, (3) photovoltaic and inductive devices for power supply, (4) experimentally validated, analytical models of transience, suitable as design tools for engineered behaviours and (5) integrated examples in wirelessly controlled, bio resorbable devices that provide thermal therapy in an implantable form. Because this technology is based on silicon, it can exploit many modern, established aspects of device and circuit design, with operational characteristics that can match those of nontransient counterparts formed in the usual way on wafer substrates. This result, taken together with supporting technologies in sensors, power supply and wireless control, provides access to qualitatively more sophisticated capabilities than those available with recently reported forms of organic electronics in which certain constituent materials are water soluble [1 3] or simple non transient transistors formed on bio resorbable substrates [4] Figure 1a, b and S1 provide images and schematic diagrams of a demonstration platform for the technology. All of the components shown here, ranging from the inductors, capacitors, resistors, diodes, transistors, interconnects and crossovers, to the substrate and encapsulation layers disappear completely, through reactive dissolution by hydrolysis, as illustrated in the time sequence of images in Fig. 1c. This example of transient electronics uses magnesium (Mg) for the conductors, magnesium oxide (MgO) and silicon dioxide (SiO2) for the dielectrics, monocrystalline silicon (Si) NMs for the semiconductors, and silk (not only water soluble but also enzymatically degradable [4, 5] for the substrate and packaging material. The fabrication involves a combination of transfer printing (Si NMs) physical vapour deposition through fine line stencil masks (Mg, MgO, SiO2) and solution casting (silk) (See Methods and SI for details. In some cases, we used minute amounts of titanium to promote adhesion of Mg. Device fabrication was possible without this layer, although with somewhat lower yields in certain cases. The chemical reactions responsible for dissolution of each material appear in Fig. 1d. The Si NMs and layers of SiO2 are particularly important, due to their essential roles in high performance transistors, diodes, photodetectors, solar cells, temperature sensors, strain Hwang et al. Page 2 Science. Author manuscript; available in PMC 2013 September 30. N IH PA Athor M anscript N IH PA Athor M anscript N IH PA Athor M anscript gauges and other semiconductor devices, as described subsequently. For both, hydrolysis forms ortho silicic acid (Si(OH)4) whose water solubility is ~0.10 g/L at room temperature, as determined from studies of nanoporous silicon bodies [6 8] The NM geometry is important because it enables high performance devices and planar architectures, minimizes the amount of material that must be consumed during the transient step, and provides mechanics and processing options that are favourable for heterogeneous integration onto substrates such as silk [4] The second characteristic allows access to high rates of transience while avoiding solubility limits and potentially adverse biological responses, for applications where bio compatibility is important. A typical transistor described here involves less than ~1 mg of Si, which can be dissolved as Si(OH)4 in as little as 30 mL of water (or bio fluid) [8] Straightforward reductions in the dimensions of the devices could decrease even further the required amount of Si. For example, the mass of Si in the active region of a conventional MOSFET built on an ultrathin silicon on insulator wafer is ~10 fg, which corresponds to solubility in as little as ~300 fL [9] Figure 2a presents atomic force micrographs of a Si NM (3 x 3 mm) with thickness of 70 nm, collected at different stages of dissolution in phosphate buffer solution (PBS; pH of 7.4) at a physiologically relevant temperature (37 degC) to simulate transience by bio resorption (See Fig. S2 for different thicknesses of Si NM) The kinetics can be captured analytically using models of reactive diffusion (Fig. 2b; SI for details) [10 12] in which the rate limiting step is defined by diffusion of water and hydroxyl ions into the Si and reaction throughout the thickness direction y, according to [13 15] where D and k are the diffusivity for water and the reaction constant between silicon and PBS, respectively, and w is the concentration of water. Upon dissolution, the following equilibrium is formulated: Si +4H2O Si(OH)4+2H2, where the neutral silicic acid leaves the silicon surface by diffusion. In this model, the thickness of the Si NM (h) normalized by its initial thickness (h0) depends on the normalized time and reaction constant according to", "author_names": [ "Suk-Won Hwang", "Hu Tao", "Dae-Hyeong Kim", "Huanyu Cheng", "Jun-Kyul Song", "", "Mark A Brenckle", "Bruce J B Panilaitis", "Sang Min Won", "Yun-Soung Kim", "Ki Jun Yu", "Abid Ameen", "Rui Li", "Yewang Su", "Miaomiao Yang", "David Lee Kaplan", "Mitchell R Zakin", "Marvin J Slepian", "Yonggang Huang", "Fiorenzo G Omenetto", "A John" ], "corpus_id": 201075758, "doc_id": "201075758", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "A Physically Transient Form of Silicon Electronics With Integrated Sensors Actuators and Power Supply", "venue": "", "year": 2013 }, { "abstract": "Flexible transient photodetectors, a form of optoelectronic sensors that can be physically self destroyed in a controllable manner, could be one of the important components for future transient electronic systems. In this work, a scalable, device first, and bottom up thinning process enables the fabrication of a flexible transient phototransistor on a wafer compatible transferred silicon nanomembrane. A gate modulation significantly restrains the dark current to 10 12 A. With full exposure of the light sensitive channel, such a device yields an ultrahigh photo to dark current ratio of 107 with a responsivity of 1.34 A W 1 (l 405 nm) The use of a high temperature degradable polymer transient interlayer realizes on demand self destruction of the fabricated phototransistors, which offers a solution to the technical security issue of advanced flexible electronics. Such demonstration paves a new way for designing transient optoelectronic devices with a wafer compatible process.", "author_names": [ "Gongjin Li", "Enming Song", "Gaoshan Huang", "Ruobing Pan", "Qinglei Guo", "Fei Ma", "Bin Zhou", "Zengfeng Di", "Yongfeng Mei" ], "corpus_id": 52947667, "doc_id": "52947667", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Flexible Transient Phototransistors by Use of Wafer Compatible Transferred Silicon Nanomembranes.", "venue": "Small", "year": 2018 }, { "abstract": "This paper presents materials, device designs, and physical/electrical characteristics of a form of nanotube electronics that is physically transient, in the sense that all constituent elements dissolve and/or disperse upon immersion into water. Studies of contact effects illustrate the ability to use water soluble metals such as magnesium for source/drain contacts in nanotube based field effect transistors. High mobilities and on/off ratios in transistors that use molybdenum, silicon nitride, and silicon oxide enable full swing characteristics for inverters at low voltages ~5 V) and with high gains ~30) Dissolution/disintegration tests of such systems on water soluble sheets of polyvinyl alcohol demonstrate physical transience within 30 min.", "author_names": [ "Sung Hun Jin", "Jongmin Shin", "In-Tak Cho", "Sang Youn Han", "Dong Joon Lee", "Chi Hwan Lee", "Jongho Lee", "John A Rogers" ], "corpus_id": 16966307, "doc_id": "16966307", "n_citations": 42, "n_key_citations": 1, "score": 0, "title": "Solution processed single walled carbon nanotube field effect transistors and bootstrapped inverters for disintegratable, transient electronics", "venue": "", "year": 2014 }, { "abstract": "Transient electronics represents an emerging class of technology that exploits materials and/or device constructs that are capable of physically disappearing or disintegrating in a controlled manner at programmed rates or times. Inorganic semiconductor nanomaterials such as silicon nanomembranes/nanoribbons provide attractive choices for active elements in transistors, diodes and other essential components of overall systems that dissolve completely by hydrolysis in biofluids or groundwater. We describe here materials, mechanics, and design layouts to achieve this type of technology in stretchable configurations with biodegradable elastomers for substrate/encapsulation layers. Experimental and theoretical results illuminate the mechanical properties under large strain deformation. Circuit characterization of complementary metal oxide semiconductor inverters and individual transistors under various levels of applied loads validates the design strategies. Examples of biosensors demonstrate possibilities for stretchable, transient devices in biomedical applications.", "author_names": [ "Suk-Won Hwang", "Chi Hwan Lee", "Huanyu Cheng", "Jae-Woong Jeong", "Seung-Kyun Kang", "Jae-Hwan Kim", "Jiho Shin", "Jian Yang", "Zhuangjian Liu", "Guillermo A Ameer", "Yonggang Huang", "John A Rogers" ], "corpus_id": 22208103, "doc_id": "22208103", "n_citations": 199, "n_key_citations": 0, "score": 0, "title": "Biodegradable elastomers and silicon nanomembranes/nanoribbons for stretchable, transient electronics, and biosensors.", "venue": "Nano letters", "year": 2015 }, { "abstract": "Reactive dissolution and its effects on electrical conduction, morphological change and chemical transformation in thin films of Mg, AZ31B Mg alloy, Zn, Fe, W, and Mo in de ionized (DI) water and simulated body fluids (Hanks' solution pH 5 8) are systematically studied, to assess the potential for use of these metals in water soluble, that is, physically \"transient\" electronics. The results indicate that the electrical dissolution rates in thin films can be much different that traditionally reported corrosion rates in corresponding bulk materials. Silicon metal oxide field effect transistors (MOSFETs) built with these metals demonstrate feasibility for use in transient electronics.", "author_names": [ "Lan Yin", "Huanyu Cheng", "Shimin Mao", "Richard T Haasch", "Yuhao Liu", "Xu Xie", "Suk-Won Hwang", "Harshvardhan Jain", "Seung-Kyun Kang", "Yewang Su", "Rui Chun Li", "Yonggang Huang", "John A Rogers" ], "corpus_id": 16939898, "doc_id": "16939898", "n_citations": 261, "n_key_citations": 4, "score": 0, "title": "Dissolvable Metals for Transient Electronics", "venue": "", "year": 2014 }, { "abstract": "Significance Bioresorbable electronic systems have the potential to create important new categories of technologies, ranging from temporary biomedical implants to environmentally benign, green consumer devices. The results presented here provide a collection of ideas that establish the foundations for a realistic technology of this type, in which state of the art silicon complementary metal oxide semiconductor foundries serve as the source of microscale, water soluble electronic components configured for rapid assembly and electrical interconnection on soft, biocompatible polymer substrates. Demonstrations in various high performance electronic systems illustrate the concepts, and fundamental studies establish the chemical kinetics and end products of dissolution in aqueous environments. Foundry based routes to transient silicon electronic devices have the potential to serve as the manufacturing basis for \"green\" electronic devices, biodegradable implants, hardware secure data storage systems, and unrecoverable remote devices. This article introduces materials and processing approaches that enable state of the art silicon complementary metal oxide semiconductor (CMOS) foundries to be leveraged for high performance, water soluble forms of electronics. The key elements are (i) collections of biodegradable electronic materials (e.g. silicon, tungsten, silicon nitride, silicon dioxide) and device architectures that are compatible with manufacturing procedures currently used in the integrated circuit industry, (ii) release schemes and transfer printing methods for integration of multiple ultrathin components formed in this way onto biodegradable polymer substrates, and (iii) planarization and metallization techniques to yield interconnected and fully functional systems. Various CMOS devices and circuit elements created in this fashion and detailed measurements of their electrical characteristics highlight the capabilities. Accelerated dissolution studies in aqueous environments reveal the chemical kinetics associated with the underlying transient behaviors. The results demonstrate the technical feasibility for using foundry based routes to sophisticated forms of transient electronic devices, with functional capabilities and cost structures that could support diverse applications in the biomedical, military, industrial, and consumer industries.", "author_names": [ "Jan-Kai Chang", "Hui Fang", "Christopher A Bower", "Enming Song", "Xinge Yu", "John A Rogers" ], "corpus_id": 7325637, "doc_id": "7325637", "n_citations": 59, "n_key_citations": 0, "score": 0, "title": "Materials and processing approaches for foundry compatible transient electronics", "venue": "Proceedings of the National Academy of Sciences", "year": 2017 }, { "abstract": "Areas of application that span almost every class of microsystems technology, from electronics to energy storage devices to chemical/biochemical sensors, can benefit from options in engineering designs that exploit 3D micro/nanostructural layouts. Recently developed methods for forming such systems exploit stress release in prestretched elastomer substrates as a driving force for the assembly of 3D functional microdevices from 2D precursors, including those that rely on the most advanced functional materials and device designs. Here, concepts that expand the options in this class of methods are introduced, to include 1) component parts built with physically transient materials to allow triggered transformation of 3D structures into other shapes and 2) mechanical interlocking elements composed of female type lugs and maletype hooks that activate during the assembly process to irreversibly \"lock in\" the 3D shapes. Wireless electronic devices demonstrate the utility of these ideas in functional systems.", "author_names": [ "Haiwen Luan", "Daniel Franklin", "Wubin Bai", "Yihui Zhang" ], "corpus_id": 201230256, "doc_id": "201230256", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Transformable, Freestanding 3D Mesostructures Based on Transient Materials and Mechanical Interlocking", "venue": "Advanced Functional Materials", "year": 2019 }, { "abstract": "Transient forms of electronics, systems that disintegrate, dissolve, resorb, or sublime in a controlled manner after a well defined operating lifetime, are of interest for applications in hardware secure technologies, temporary biomedical implants, \"green\" consumer devices and other areas that cannot be addressed with conventional approaches. Broad sets of materials now exist for a range of transient electronic components, including transistors, diodes, antennas, sensors, and even batteries. This work reports the first examples of transient light emitting diodes (LEDs) that can completely dissolve in aqueous solutions to biologically and environmentally benign end products. Thin films of highly textured ZnO and polycrystalline Mo serve as semiconductors for light generation and conductors for transparent electrodes, respectively. The emitted light spans a range of visible wavelengths, where nanomembranes of monocrystalline silicon can serve as transient filters to yield red, green, and blue LEDs. Detailed characterization of the material chemistries and morphologies of the constituent layers, assessments of their performance properties, and studies of their dissolution processes define the underlying aspects. These results establish an electroluminescent light source technology for unique classes of optoelectronic systems that vanish into benign forms when exposed to aqueous conditions in the environment or in living organisms.", "author_names": [ "Di Lu", "Tzu-Li Liu", "Jan-Kai Chang", "Dongsheng Peng", "Yanwen Zhang", "Jiho Shin", "Tao Hang", "Wubin Bai", "Quansan Yang", "John A Rogers" ], "corpus_id": 201845208, "doc_id": "201845208", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Transient Light Emitting Diodes Constructed from Semiconductors and Transparent Conductors that Biodegrade Under Physiological Conditions.", "venue": "Advanced materials", "year": 2019 }, { "abstract": "Recent advances in materials chemistry establish the foundations for unusual classes of electronic systems, characterized by their ability to fully or partially dissolve, disintegrate, or otherwise physically or chemically decompose in a controlled fashion after some defined period of stable operation. Such types of \"transient\" technologies may enable consumer gadgets that minimize waste streams associated with disposal, implantable sensors that disappear harmlessly in the body, and hardware secure platforms that prevent unwanted recovery of sensitive data. This second area of opportunity, sometimes referred to as bioresorbable electronics, is of particular interest due to its ability to provide diagnostic or therapeutic function in a manner that can enhance or monitor transient biological processes, such as wound healing, while bypassing risks associated with extended device load on the body or with secondary surgical procedures for removal. Early chemistry research established sets of bioresorbable materials for substrates, encapsulation layers, and dielectrics, along with several options in organic and bio organic semiconductors. The subsequent realization that nanoscale forms of device grade monocrystalline silicon, such as silicon nanomembranes (m Si NMs, or Si NMs) undergo hydrolysis in biofluids to yield biocompatible byproducts over biologically relevant time scales advanced the field by providing immediate routes to high performance operation and versatile, sophisticated levels of function. When combined with bioresorbable conductors, dielectrics, substrates, and encapsulation layers, Si NMs provide the basis for a broad, general class of bioresorbable electronics. Other properties of Si, such as its piezoresistivity and photovoltaic properties, allow other types of bioresorbable devices such as solar cells, strain gauges, pH sensors, and photodetectors. The most advanced bioresorbable devices now exist as complete systems with successful demonstrations of clinically relevant modes of operation in animal models. This Account highlights the foundational materials concepts for this area of technology, starting with the dissolution chemistry and reaction kinetics associated with hydrolysis of Si NMs as a function of temperature, pH, and ion and protein concentration. A following discussion focuses on key supporting materials, including a range of dielectrics, metals, and substrates. As comparatively low performance alternatives to Si NMs, bioresorbable organic semiconductors are also presented, where interest derives from their intrinsic flexibility, low temperature processability, and ease of chemical modification. Representative examples of encapsulation materials and strategies in passive and active control of device lifetime are then discussed, with various device illustrations. A final section outlines bioresorbable electronics for sensing of various biophysical parameters, monitoring electrophysiological activity, and delivering drugs in a programmed manner. Fundamental research in chemistry remains essential to the development of this emerging field, where continued advances will increase the range of possibilities in sensing, actuation, and power harvesting. Materials for encapsulation layers that can delay water diffusion and dissolution of active electronics in passively or actively triggered modes are particularly important in addressing areas of opportunity in clinical medicine, and in secure systems for envisioned military and industrial uses. The deep scientific content and the broad range of application opportunities suggest that research in transient electronic materials will remain a growing area of interest to the chemistry community.", "author_names": [ "Seung-Kyun Kang", "Jahyun Koo", "Yoon Kyeung Lee", "John A Rogers" ], "corpus_id": 4938079, "doc_id": "4938079", "n_citations": 89, "n_key_citations": 0, "score": 0, "title": "Advanced Materials and Devices for Bioresorbable Electronics.", "venue": "Accounts of chemical research", "year": 2018 } ]

[ { "abstract": "Abstract When semiconductor developers noticed in the 1950s that electropolishing of bulk silicon left certain areas rougher than the rest and somewhat porous, they regarded these simply as imperfect areas. It was not until Leigh Canham, a scientist with DERA (the UK's Defence Evaluation and Research Agency) discovered in 1990 that porous silicon (PSi) emits visible light when activated by external ultraviolet sources 1 that this morphological state of the material came to attract significant research interest. Elementary photonic sensors were soon proposed. In 1992 researchers discovered that PSi also emits light when an electric current is applied, a finding that raised prospects for new optronic sensors and other devices coupling light to electronics, including future high speed computers. Technology extensions have since been found that make the material chemi and bio luminescent as well as photo and electro luminescent. In sight by the mid to late 1990s, therefore, was a whole new class of solid state sensors offering significant advantages over solid state gas and other sensors. Many of these were based on bulk silicon and semiconducting oxides such as tin or indium oxide and alumina. Compared with them, PSi offers a high surface area to volume ratio and hence high reactivity and, as researchers have established, a porous structure whose morphology could be engineered for high selectivity to particular molecules. Along with high sensitivity and selectivity, comes a rapid response time.", "author_names": [ "G Marsh" ], "corpus_id": 137099923, "doc_id": "137099923", "n_citations": 31, "n_key_citations": 1, "score": 1, "title": "Porous silicon a useful imperfection", "venue": "", "year": 2002 }, { "abstract": "As subwavelength nanostructures are receiving increasing attention for photonic and plasmonic applications, we grew nanostructured porous silicon (n PS) and hybrid n PS/Ag layers onto silicon substrates and measured their reflection and absorption characteristics as functions of the wavelength, angle of incidence, and polarization state of incident light. The experimental results show that the absorption characteristics of the hybrid n PS/Ag layer can be controlled by selecting the appropriate combination of its thickness and porosity, together with the density of infiltrant silver nanoparticles. The observed wideband optical absorption characteristics of the hybrid n PS/Ag layers might be useful in light harvesting devices and photodetectors, since the overall efficiency will be increased as a result of increased field of view for both s and p polarization states of incident light.", "author_names": [ "Raul Jose Martin-Palma", "Patrick D Mcatee", "Rehab Ramadan", "Akhlesh Lakhtakia" ], "corpus_id": 152283296, "doc_id": "152283296", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Hybrid Nanostructured Porous Silicon Silver Layers for Wideband Optical Absorption", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "a b s t r a c t This review is devoted to summarising the hydrogen assisted properties and applications of porous silicon (PS) The role of hydrogen as an intermediate product in silicon porosification technology is accentuated. The regularities of hydrogen bonding in PS and its applications for hydrogen storage are listed. The models of hydrogen influence on luminescence and electrical properties of PS are analysed. The corresponding applications of PS for H2 gas sensors and pH metres are illustrated. Hydrogen assisted explosion and grafting of PS are discussed. Such a review can be useful for the tailoring of PS properties.", "author_names": [ "Anton I Manilov", "Valeriy A Skryshevsky" ], "corpus_id": 93521349, "doc_id": "93521349", "n_citations": 38, "n_key_citations": 0, "score": 0, "title": "Hydrogen in porous silicon A review", "venue": "", "year": 2013 }, { "abstract": "Abstract Porous silicon (PSi) has a high chemical energy, which has the potential to be converted to mechanical energy very quickly through ignition. Here we investigate a means to convert this mechanical energy to electrical energy via a piezoelectric cantilever and rectifying circuit. This current could be used to power sensors, devices, or store charge, and this type of system could be useful in ignition systems for munitions. The efficiency of this system is critical to realizing the potential for PSi as a one time electrical energy source. A mechanical to electrical efficiency of 4.1 was achieved, but the chemical to electrical efficiency was much less than 1", "author_names": [ "Louis B Levine", "Matthew H Ervin", "Wayne A Churaman" ], "corpus_id": 113919825, "doc_id": "113919825", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Energy Harvesting from Energetic Porous Silicon", "venue": "", "year": 2016 }, { "abstract": "Abstract An express technique to define the thickness and rate of porous silicon (PS) layer growth during the electrochemical etching of silicon wafers is proposed. The method is based on the in situ measurement of reflected laser beam from PS layer in electrochemical cell during the etching process. Numerical simulation of the wavelength dependent interference data obtained from the reflectivity showed the possibility of the selectivity improvement of thin layer PS sensors by the use of a set of PS layers with defined thicknesses and porosities. The different behavior of the reflection coefficients, shape and position of the maxima of the interference peaks during desorption of water ethanol solutions and wines from the PS films were observed. The differences in the peak shape indicated the presence of inhomogeneity in the distribution of the film porosity with depth. On the other hand, the differences in the interaction modes between the adsorbed molecules and the pore surface caused differences in the kinetics of the optical characteristics during the desorption. The obtained results could be useful for development of selective optical sensors based on porous materials.", "author_names": [ "Nickolai I Klyui", "I I Ivanov", "Oleksandr S Kyslovets", "Lyubov V Avksentyeva", "Valeriy A Skryshevsky" ], "corpus_id": 102406358, "doc_id": "102406358", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Features of the use of optical reflection from thin porous silicon for detection of organic liquids", "venue": "", "year": 2017 }, { "abstract": "Abstract We report a detailed study on the concentration profiles and ion irradiation induced desorption of hydrogen from porous silicon (pSi) by on line elastic recoil detection analysis (ERDA) 100 MeV Ag ions have been employed to analyze the pSi samples prepared at different etching current densities. The observed blue shift in the photoluminescence of pSi with increase in etching current density is consistent with previous reports. Here we find that the concentration of hydrogen in near surface regions decreases with increase in etching current density. It is also observed that the concentration of hydrogen is greater in the near surface region and decreases rapidly as a function of depth in porous silicon. Further, the ion irradiation induced desorption of hydrogen from pSi has been characterized by the second order decay, indicating that the hydrogen desorbs in molecular form. The rate of desorption is found to be higher from the deeper layers when compared to that of near surface regions, possibly due to higher diffusivity of elemental hydrogen within the deeper layer. Strong electronic excitations produced by probing beam are expected to be responsible for the observed non thermal dissociation of Si H bonds and consequent desorption of hydrogen from the surface of pSi in molecular form. These results provide useful information to elucidate 1) the role of hydrogen in determining the optical properties of porous/nano crystalline silicon and 2) mechanisms that govern the non thermal dissociation of Si H bonds.", "author_names": [ "V S Vendamani", "S A Khan", "M Dhanunjaya", "A P Pathak", "S V S Nageswara Rao" ], "corpus_id": 99442189, "doc_id": "99442189", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Energetic ion induced desorption of hydrogen from porous silicon studied by on line elastic recoil detection analysis", "venue": "", "year": 2017 }, { "abstract": "A systematic study of nanoenergetic films consisting of nanostructured porous silicon impregnated with sodium perchlorate is carried out. The explosive properties of these films are investigated as a function of thickness, porosity, and confinement. The films' burning rates are investigated using fiber optic velocity probes, demonstrating that flame front velocities vary between approximately 1 and 500 m s( 1) and are very sensitive to the films' structural characteristics. Analysis of the flame profile by high speed video is also presented, suggesting that the reaction type is a deflagration rather than a detonation. A strong plume of flame is emitted from the surface, indicating the potential for this material to perform useful work either as an initiator or as a propellant. The shape of the flame front transitioned from an inverted V at thin film thicknesses to a neat square shaped front once the material became self confining at 50 mm.", "author_names": [ "Andrew Plummer", "Valerian A Kuznetsov", "Timothy Joyner", "Joseph G Shapter", "Nicolas Hans Voelcker" ], "corpus_id": 28241628, "doc_id": "28241628", "n_citations": 42, "n_key_citations": 0, "score": 0, "title": "The burning rate of energetic films of nanostructured porous silicon.", "venue": "Small", "year": 2011 }, { "abstract": "A capacitive sensor based on porous silicon (PSi) for detection of various polar (ethanol, methanol, acetone, acetonitrile, chloroform) and non polar organic solvents (n hexane, toluene) was described. The meso PSi layer with an average pore size of 30 nm was prepared by a galvanostatic electrochemical etching of crystalline silicon in HF based solution. Surface passivation was conducted by anodic oxidation process and the electrical contacts were made exclusively onto the front porous structure. The as fabricated sensor exhibits highly sensitive and reversible response toward polar organic molecules during the real time measurements of capacitance, whereas the capacitive sensing behavior was irreversible and opposite in direction in case of non polar solvents. The response time was in the order of acetone methanol acetonitrile ethanol chloroform. The observed response could be understood as the impact of charge redistribution on the pore walls upon organic infiltration, along with changes in the dielectric constant of the porous layer. A comparative study of such different responses is provided. Excellent repeatability of the device was obtained after twelve cyclic tests of acetone, demonstrating stability of the sensor. Long term stability for the sensor was also observed after four weeks storage. The present approach is useful for the development of a simple, cost effective sensor for detection of various chemical analytes.", "author_names": [ "Farid A Harraz", "Adel A Ismail", "Houcine Bouzid", "Saleh A Al-Sayari", "Ali Al-Hajry", "M Al-assiri" ], "corpus_id": 96689330, "doc_id": "96689330", "n_citations": 34, "n_key_citations": 1, "score": 0, "title": "A capacitive chemical sensor based on porous silicon for detection of polar and non polar organic solvents", "venue": "", "year": 2014 }, { "abstract": "The modern development of nanotechnology requires the discovery of simple approaches that ensure the controlled formation of functional nanostructures with a predetermined morphology. One of the simplest approaches is the self assembly of nanostructures. The widespread implementation of self assembly is limited by the complexity of controlled processes in a large volume where, due to the temperature, ion concentration, and other thermodynamics factors, local changes in diffusion limited processes may occur, leading to unexpected nanostructure growth. The easiest ways to control the diffusion limited processes are spatial limitation and localized growth of nanostructures in a porous matrix. In this paper, we propose to apply the method of controlled self assembly of gold nanostructures in a limited pore volume of a silicon oxide matrix with submicron pore sizes. A detailed study of achieved gold nanostructures' morphology, microstructure, and surface composition at different formation stages is carried out to understand the peculiarities of realized nanostructures. Based on the obtained results, a mechanism for the growth of gold nanostructures in a limited volume, which can be used for the controlled formation of nanostructures with a predetermined geometry and composition, has been proposed. The results observed in the present study can be useful for the design of plasmonic active surfaces for surface enhanced Raman spectroscopy based detection of ultra low concentration of different chemical or biological analytes, where the size of the localized gold nanostructures is comparable with the spot area of the focused laser beam.", "author_names": [ "Dzmitry V Yakimchuk", "Victoria D Bundyukova", "Jon Ustarroz", "Herman Terryn", "Kitty Baert", "Artem L Kozlovskiy", "Maxim V Zdorovets", "Soslan A Khubezhov", "Alexey Trukhanov", "Sergei V Trukhanov", "Larissa V Panina", "Grigory M Arzumanyan", "Kahramon Z Mamatkulov", "Daria I Tishkevich", "Egor Y Kaniukov", "Vladimir Sivakov" ], "corpus_id": 221108627, "doc_id": "221108627", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Morphology and Microstructure Evolution of Gold Nanostructures in the Limited Volume Porous Matrices", "venue": "Sensors", "year": 2020 }, { "abstract": "There are a vast number of applications for biosensors ranging from medical monitoring and control, to release of drugs [1] and biosecurity [2] The goblal market for biosensors in 2012 is estimated to reach 8.5 billion USD and projected to reach 16.8 billion by 2018 [3] Po rous silicon (p Si) offers several advantages for its use as a biosensor such as a large specific surface area (of the order of 500 m 2 cm 3) [4] visible luminescence at room temperature [5] and biocompatibility [6] The p Si was accidentally discovered when, in 1956 at the U.S. Bell Laboratories, Arthur Uhlir Jr. and Ingeborg Uhlir observed a red green film formed on the wafer surface while trying a new technique for polishing silicon (Si) crystalline wafers. At the time however, it was not considered an interesting material. But when Leigh Canham in 1990 [5] discovered its visible luminescence properties, researchers started studying its non linear optical, electric and mechanical properties. These academic and technological efforts have permitted the fabrication of uniform porous layers with diameters as small as one nanometer, permitting an enormous inner surface density, which is useful for biosensing ap plications. Several techniques exist to form this structure from a pure silicon crystalline wa fer. The most popular is the electrochemical etching of crystalline silicon wafers (c Si) [5] Anodization begins when a constant current is applied between the c Si wafer and the elec trolyte by means of an electronic circuit controlling the anodization process [6]", "author_names": [ "M B de la Mora", "Miguel A Ocampo", "Rafael Doti", "Jesus Eduardo Lugo", "Jocelyn Faubert" ], "corpus_id": 1808984, "doc_id": "1808984", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Chapter 6 Porous Silicon Biosensors", "venue": "", "year": 2013 } ]

[ { "abstract": "This paper presents a review and analysis of multilevel inverter topologies. Multilevel inverters are most widely used for medium voltage high power converter like fans, pumps and material transport drives. In this active area, different inverter topologies, circuits, advantages and drawbacks are discussed. Multilevel Inverter topologies such as diode clamped, flyingcapacitor, cascaded H bridge, hybrid H bridge, new hybrid H bridge and new cascaded multilevel inverter have been discussed in the literature. In this work a new idea is developed to increase the level with less number of switches. It is concluded that the topologies are closely related to each particular application, depending on their unique features and limitations like power or voltage level, performance, reliability, costs and other technical specifications. I .INTRODUCTION Numerous industrial applications have began to require higher power apparatus in recent years. Some medium voltage motor drives and utility applications require medium voltage and MW power level. For a medium voltage grid, it is troublesome to connect one power semiconductor switch directly. The application of ac variable frequency speed regulations are widely popularized high power and medium voltage inverter has recently become a research focus so far as known there are many problems in conventional two level inverter in the high power application. Multilevel inverter have been gained more attention for high power application in recent years which can operate at high switching frequencies while producing lower order harmonic components[1] [6] A multilevel inverter not only achieves high power ratings, but also enables the use of renewable energy sources. Renewable energy sources such as photovoltaic, wind, and fuel cells can be easily interfaced to a multilevel inverter system for a high power application [7] [12] There are several topologies such as neutral point clamped inverter, flying capacitor based multilevel, cascaded H bridge multilevel inverter, hybrid H bridge multilevel inverter and new hybrid H bridge multilevel inverter [13] [15] Figure 1 shoes the various multilevel inverter topologies. This paper discusses the operation of different topologies for multilevel inverter which can produce multilevel; under this condition neutral point clamped multilevel inverter is presented, which has a simple structure and good performance .This topology effectively reduce the higher input dc voltage that each device must withstand. The main disadvantage still exists in this topology, which restricts the use of it to the high power range of operation [16] [20] The first topology introduced is the series H bridge design [21] [22] from this several configurations have been obtained. This topology consists of series power conversion cells which form the cascaded Hbridge multilevel inverter and power levels may be scaled easily. An apparent disadvantage of this topology is the large number of isolated voltage required to supply each cell. By using H bridge power conversion cells several topologies are developed and their advantages and disadvantages are discussed. The proposed topology for multilevel inverter has a high number of steps associated with a low number of power switches. In addition for producing all levels at the output voltage, a procedure for calculating the required dc voltage source is proposed. Figure 1.Types of Multilevel Inverter Topologies II.DIODECLAMPED MULTI LEVEL INVERTER: A three phase six level diode clamped inverter is shown in figure.2. Each of the three phases of the inverter shares a common dc bus, which has been subdivided by five capacitors into six levels. The voltage across each capacitor is Vdc and the voltage stress across each switching device is limited to Vdc through the clamping diodes. This involves the (n 1) main dc link capacitors and also S (2n 2) clamping diodes, where n number of levels. For DCMLI requires a large number of clamping devices as 2n 2. Each phase has five complementary switch pairs such that turning on, one of the switches of the pair require that the other complementary switch be turned off. The complementary switch pairs for phase leg a are (Sa1, Sa'1) (Sa2, Sa'2) (Sa3, Sa'3) (Sa4, Sa'4) and (Sa5, Sa'5) The figure.3 shows the line voltage waveform of a fifteen level diode clamped multilevel inverter. The main advantages are the entire phases share a common dc bus, which minimizes the capacitance requirements of the converter. For this reason, a back to back topology is not possible and can be practically used for a highvoltage back to back inter connection or an adjustable speed drive. The capacitors can be precharged as a group and efficiency is high for fundamental frequency switching. The main draw backs are real power flow is difficult for a single inverter because the intermediate dc levels will tend to overcharge or discharge without precise monitoring and control. The number of clamping diodes required is quadratically related to the number Murugesan et al. International Journal of Advanced Engineering Technology E ISSN 0976 3945 Int J Adv Engg Tech/Vol. VII/Issue I/Jan. March.,2016/149 155 of levels, which can be cumbersome for units with a high number of levels [23] [30] Figure 2. Three phase diode clamped multilevel inverter Figure 3. Line voltage waveform of diode clamped multilevel inverter III.FLYING CAPACITOR BASED MULTILEVEL INVERTER: The FCMLI requires a large number of capacitors to clamp the device (switch) voltage to one capacitor voltage level provided all the capacitors are of equal value, an n level inverter will require a total number of (n 1)(n 2)/2 clamping capacitors per phase leg in addition to (n 1) main dc bus capacitors. Figure.4 shows the three phase six level flying capacitor based multilevel inverter. Let us consider the group of capacitors in a single clamping leg as one equivalent capacitor, which is also applicable for 'n' level inverter. If the voltage of the main dc link capacitor is Vdc, the voltage of inner most capacitor, the inner most two devices is Vdc/ (n 1) The voltage of the inner most capacitor will be Vdc/ (n 1) Vdc/ (n 1) 2Vdc/ (n 1) and so on. Each next clamping capacitor will have the voltage increment of Vdc/ (n 1) from its immediate inner one voltage levels. The arrangements of the flying capacitors in the FCMLI structure assures that the voltage stress across each main device is same and is equal to Vdc/ (n 1) for an 'n' level inverter. The advantages of this topology are phase redundancies are available for balancing the voltage levels of the capacitors, real and reactive power flow controlled. Figure 4. Three phase Flying Capacitor based Multilevel Inverter The large number of capacitors enables the inverter to ride through short duration outages and deep voltage sags. The main draw back of this topology is complicated to track the voltage levels for all of the capacitors. Also the pre charging of all the capacitors to the same voltage level and startup are complex. Switching utilization and efficiency are poor for real power transmission. The large numbers of capacitors are more expensive and bulky than clamping diodes in multilevel diode clamped converters. Packaging is also difficult in inverters with a high number of levels [31] [40] The figure.5 shows the line voltage waveform of a fifteen level diode clamped multilevel inverter. Figure 5. Line voltage waveform of flying capacitor based multilevel inverter IV.CASCADED H BRIDGE MULTILEVEL INVERTER: The general structure of the cascaded multilevel inverter for single phase is shown in figure 6. Each of the separate voltage source (Vdc1, Vdc2, Vdc3) connected in cascade with other sources via a special H bridge circuit associated with it. Each of the circuit consists of four active switching elements that can make the output voltage source in positive or negative polarity; or it can be simply zero volts depending on the switching condition of the switches in the circuit. A conventional multilevel power inverter topology employs multiple/link voltage of equal magnitudes. It is fairly easy to generalize the number of distinct levels. [41][55] Figure 6.Topology for Cascaded H Bridge Multilevel", "author_names": [ "M Murugesan", "R Pari", "R Sivakumar", "S Sivaranjani" ], "corpus_id": 27230960, "doc_id": "27230960", "n_citations": 10, "n_key_citations": 0, "score": 1, "title": "DIFFERENT TYPES OF MULTILEVEL INVERTER TOPOLOGIES A TECHNICAL", "venue": "", "year": 2016 }, { "abstract": "Since the introduction of the power electronic power supplies, the electrical insulation of low voltage motors faces new hazards. Especially the primary insulation of the magnet wire is endangered due to the use of frequency inverters. As an effect, partial discharges may appear causing degradation of the electrical insulation to lead finally to a premature breakdown of the machine. This study shows the impact of ozone, generated during partial discharge activity, on the lifespan of samples used to model the winding of the machine. Different types of magnet wires, composed of different enamel polymer, both conventional and corona resistant, were tested in this paper. The results state that the mean time to failure is up to 25% shorter if the ozone is not evacuated from the test chamber and samples are exposed to its degrading properties. This is the case for close machines, in which the air embedded between the stator and the rotor and within the slot is not ventilated, thus allowing ozone to accumulate to significant concentrations.", "author_names": [ "Mateusz Szczepanski", "David Malec", "Pascal Maussion", "Benoit Petitgas", "Philippe Manfe" ], "corpus_id": 23927861, "doc_id": "23927861", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Ozone concentration impact on the lifespan of enameled wires (conventional and corona resistant) for low voltage rotating machines fed by inverters", "venue": "2017 IEEE Electrical Insulation Conference (EIC)", "year": 2017 }, { "abstract": "Performance of any digital control scheme applied to inverters, or any other power electronic structures, can significantly suffer due to time delays. These time delays can be linear and nonlinear. An example of a linear delay is the delay due to sampling, control calculation and application of the new voltage state, which results in a constant delay present in each control cycle. An example of a non linear delay is the inverter dead time, which is different depending on the selected switching state and the direction of the load current. Both types of delays are well known and are addressedin literature. At the same time, the known solutions result in significantly more complicated hardware and/or software implementations. Introduction of MPC to power electronics gives a new and unique opportunity to compensate for both types of the delays in a clear and effective way. This can be done by including the delays, both linear and non linear, in the model predictions. As an illustration, this paper presents an MPC based design of closed loop current control with linear delay compensation for voltage source inverters. The paper also proposes a variable rate MPC based voltage modulator which combines harmonic suppression with inverter dead time compensation. The main points of the paper are illustrated by extensive simulation and experimenal results.", "author_names": [ "Galina Mirzaeva", "Graham C Goodwin", "Christopher David Townsend" ], "corpus_id": 23927394, "doc_id": "23927394", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Dealing with linear and nonlinear time delays under model predictive control of power electronic inverters", "venue": "2016 IEEE International Conference on Automatica (ICA ACCA)", "year": 2016 }, { "abstract": "The paper explains about general introduction to the inverter, different types of inverter and applications of the inverters in the various fields. Dual Buck Full Bridge Inverter topology, different PWM switching methods with description, design of DBFBI and selection of switching devices are discussed in the present chapter. On the other hand, this paper also states the implementation of SIMULINK blocks of Dual Buck Inverter with PWM control unit, results obtained and discusses the analysis of various results. Also, the results obtained from simulation work are analyzed. Total harmonic distortion present in the AC output current under different bipolar PWM methods is calculated. Few important conclusions drawn out of the present project work and scope for the future work", "author_names": [ "Varsha Thakur", "Rakesh Nalgonda", "Mohammed Azam Mohammed Dastagir", "Akshatha Arjun Babu Naidu" ], "corpus_id": 203164369, "doc_id": "203164369", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "New Hybrid PWM technique for dual buck inverter", "venue": "", "year": 2019 }, { "abstract": "Distributed voltage control using \\boldsymbol{Q}\\boldsymbol{U} characteristics is a means to facilitate higher penetrations of decentralized generation. However, stability concerns interfere the wider adoption of this technology. Based on a recent introduction of a robust stability criterion for assessment of droop controlled inverters, this paper aims to improve the modeling of the grid from a control engineering point of view. After analyzing the impact of different types of voltage deviation on nodal voltage sensitivity, a more precise grid model is presented using algorithmic differentiation. The derived model is further implemented in a closed loop scheme for a \\boldsymbol{Q}\\boldsymbol{U} controller. Considering in a first step of evolution solely a single input single output system the existing stability criterion could be improved in terms of accuracy.", "author_names": [ "Friederike Thomas", "Sebastian Krahmer", "Jan Winkler", "Peter Schegner", "Klaus Robenack" ], "corpus_id": 208210513, "doc_id": "208210513", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "On Grid Modeling for Stability Assessment of Droop Voltage Control", "venue": "2019 IEEE PES Innovative Smart Grid Technologies Europe (ISGT Europe)", "year": 2019 }, { "abstract": "Among the different types of inverters for the solar power generation, the impedance source (Z Source) inverter finds a significant role due to its boosting characteristics. Since the source for this proposed work is solar energy, the inverter with impedance will give a sufficient level of voltage for the load. The output of the proposed is given to a three phase asynchronous type of motor, which is commonly used by the farmers in their agricultural pumps. Even though the inverter is working under heavy stress due to the output of the Z Source, necessary filter arrangement is made to get smooth alternate energy for running the motor. The entire arrangement is modeled using MATLAB/SIMULINK and the results are analyzed with the help of THD (Total Harmonic Distortion) values of output voltage and current. KEYWORDSSolar energy, Z Source inverter, asynchronous motor, Total Harmonic Distortion INTRODUCTION Nowadays the thirsty for power has increased manifold due to the enormous growth in industries and population. But the resources of traditional or conventional power have been drastically reduced and they may be available for four or five decades of future. Also the abundant use of conventional or non renewable energy resources, various environmental problems like air pollution, water pollution etc have increased and all become a intimidation for the whole human society. Hence the searching for alternate energy has become a timely needed one. Among the various renewable energy sources like solar, thermal, hydro, biomass and wind energy, the solar energy is the most promising one among them. Solar energy is a radian light and heat from the sun that is harnessed using a range of ever evolving technologies such as solar heating, photo voltaic, solar thermal energy, solar architecture, molten salt power plants and artificial photo synthesis. The large magnitude of solar energy availability makes it a highly appealing source of electricity. The United Nations development programme in its world energy assessment found that the annual potential of solar energy was 1600 to 50000 exa joules [EJ] This is several times larger than the total world energy consumption which was 559.8EJ in 2012. The benefits of renewable energy resources reduce the pollution, lower the costs of mitigating global warming keep fossil fuel prices lower. These advantages are global. Solar energy has the greatest potential of all the sources of renewable energy. Also the farmers in our country are facing power problem for their agricultural pumping motors moreover in all seasons in all states. Moreover the price per unit cost of the power also has become a burden for the farmers. Hence the proposed work aims in harnessing solar energy in a prominent way, which will help the farmers and the environment. In this work, an asynchronous machine is made to run by using solar energy with the help of PWM techniques and a 3 phase inverter. The solar energy is dynamic nature, but it is necessary to give a continuous supply for the motor even the solar energy is not inadequate. In this work the solar energy generated by the solar panel, is stepped up by using impedance network. Generally the Z source network consists of two inductors and two capacitors. In the modified Z source network, in addition to two capacitor, one capacitor is added parallel to the source. Added capacitor boosts the voltage from the source and also acts as filter. The hardware results are validated with the analysis of total harmonic distortion of output voltage and current of the three phase inverter. PROPOSED SYSTEM The proposed system with Modified Z source inverter is shown in figure1. Fig 1. Block diagram of the proposed model (c) 2018 JETIR September 2018, Volume 5, Issue 9 www.jetir.org (ISSN 2349 5162) JETIRA006377 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 338 The primary objective of designing the proposed work is harness the solar energy for the agriculture purposes mainly in the irrigation pumping motors. Present day farmers all over the country are facing numerous problems including power bill due to the irrigation pump motors. In order to find a solution for the above said problem, the work has been proposed. In this proposed work the modified impedance source network is used along with the inverter instead of using the inverter alone. To ensure the boosting of the energy to the inverter, the modified impedance source network is connected parallel to the inverter. The primary source for the inverter is solar energy and pulse width modulator (PWM) controller is used to control the three phase inverter. The alternating three phase energy is fed to the asynchronous motor. The output of the inverter and output of the motor are analyzed by using the MATLAB software with total harmonic distortion values. Solar panel Photovoltaic cells are produced by semiconductor technology to convert solar light energy into electrical energy in the form of Direct Current", "author_names": [ "Dr Arulprakash Andigounder", "Vijayalakshmi Yarra", "Dhanalakshmi Malothu" ], "corpus_id": 214794161, "doc_id": "214794161", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "COMPANIONABILITY OF MODIFIED Z SOURCE INVERTER WITH SOLAR POWER GENERATION FOR A 3O ASYNCHRONOUS MOTOR", "venue": "", "year": 2018 }, { "abstract": "In this Modified half bridge and full bridge topologies with continuous input current by using switched boost inverter are proposed. In this paper, the operation of the proposed inverters in different operating modes is analyzed. In addition, these topologies have high boost factor in comparison with conventional types. The proposed topologies have continuous input current and can generate zero voltage level in output. Then, the values of inductors and capacitors are designed. Comprehensive comparison between the proposed and conventional topologies in terms of boost factor, number of elements and efficiency shows in the proposed inverters. Finally, to verify operation of the proposed topologies by simulation. INTRODUCTION: Z source inverter (ZSI) and quasi Z source inverter (QZSI) have been presented. In switched inductor cells have been used in conventional ZSI to increase voltage gain. In this topology based on cascaded switched inductor cells has been used, which is named L Z source inverter (LZSI) The switched inductor Z source inverter (SLZSI) has improved the value of boost factor All presented topologies in use many passive elements. Hence, to reduce the number of passive elements in conventional topologies, switched boost inverter (SBI) has been presented. To improve and develop the characteristic of SBI, current fed switched inverter (CFSI) has been presented. To increase the boost factor in CFSI, developed switched Z source inverter (DSZSI) has been presented. All presented topologies utilize full bridge inverter in their power circuits and also half bridge inverter is possible. Half bridge Z source inverter (HBZSI) iS uses in two impedance networks (Z networks) In for application in electrochemical and electroplating industry and so. The proposed full bridge inverter has eight operating modes. In the first and fifth operating modes, all switches S1,S2,S3 and S4 are ON. So, the proposed fullbridge inverter is in ST state. In other operating modes, only one of the switches on each leg is ON. So, the proposed fullbridge inverter is in nST state. The analysis of proposed half bridge inverter is very similar to analysis of proposed as fullbridge inverter. The value of boost factor in full bridge inverter is equal but voltage stress on capacitors has been decreased by 50% to value of boost factor in half bridge inverter. It is noticeable that by selecting low values for inductance and switching frequency and high value for output load, number of operating modes will be more than eight. In this state, waveform of output voltage in proposed full bridge inverter loses its symmetry state. The proposed inverters have only one voltage source and few passive elements, including one inductor and few capacitors. It is noticeable that the proposed half bridge inverter has six diodes and three high side switches that these numbers are more than some of the conventional topologies. The high side switches of the proposed half bridge inverter can be driven by using bootstrap technique. In a schematic for this purpose is shown. According to this figure, the current follows a specific path to charge the bootstrap capacitor for high side driver. Hence, there is no need for expensive drivers. PROPOSED SYSTEM: The proposed topologies have continuous input current and can generate zero voltage level in output. In this operation of the proposed inverters in different operating modes is analyzed. Then, the values of inductors and capacitors are designed as per required. Moreover, used switching pattern are used and to solve the above mentioned limitations in conventional half bridge and full bridge inverters, topologies are proposed. In the proposed topologies the operation and functional principles of these topologies in different operating modes are discussed and coding are also used. Then, comparison between the proposed and conventional inverters is done. Finally, correct operation of the proposed inverters is verified by simulation in PSCAD/EMTDC software and experimental results. BLOCK DIAGRAM: Research Article Volume 8 Issue No.11", "author_names": [ "N K Rayaguru", "K N HemanthKumar Teja" ], "corpus_id": 146802091, "doc_id": "146802091", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Modified Half bridge and Full bridge Topologies with Continuous Input Current by using Switch Boost Inverter", "venue": "", "year": 2018 }, { "abstract": "The integrator of the modulator in a delta modulated (DM) inverter control scheme greatly affects the voltage waveform patterns, fundamental voltage and spectral components. The performance of DM with different types of filters suffers from low fundamental voltage. Previous schemes could not provide a fundamental voltage equal to the supply voltage and pulse dropping phenomena occurs as the modulating frequency is increased. To overcome these problems, a dual slope integrating (DSI) filter is proposed in this paper. The introduction of a DSI filter in the DM loop gives a fundamental voltage equal to the supply voltage at 100% modulation index. The number of pulses per fundamental period can be maintained constant in the modified DSI DM scheme. The performance of this modulator is better than other DM schemes so far reported. Simulations and experimental results are presented to justify the claims of the paper.", "author_names": [ "Kazi Mujibur Rahman", "M A Choudhury", "M Rezwan Khan", "M A Rahman" ], "corpus_id": 111254487, "doc_id": "111254487", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Dual slope integrator type delta modulator for high performance voltage source inverters", "venue": "Proceedings of Power Conversion Conference PCC '97", "year": 1997 }, { "abstract": "Nowadays, the high speed induction motors with solid rotors are subject of interest in many studies. These machines are supplied from frequency inverters with corresponding frequency to obtain desire rotating speed. Very simple massive solid rotor is prefer due to its mechanical strength, low cost manufacture and can be used in hostile environment. This article is focused on high speed induction motor with two different rotor types, namely smooth solid and axially slitted rotor. In the introduction the application, method of analysis and rotor topology are discussed especially for rotors, mentioned above. Our motor is designed to provide output power of 12kW and its synchronous speed is 45000 min 1. Models are created in ANSYS Maxwell software package and analyzed with approach of finite element method. Two solid rotors are examined where the first motor is equipped with smooth solid rotor which is made of single steel with no feature modification and can withstand great mechanical forces and the second motor is equipped with rotor where feature modification is applied in form of axial slits with proper depth in order to obtain better electromagnetic performance. The difference and improvement of this modification is investigated.", "author_names": [ "Jiri Klima", "Ondrej Vitek" ], "corpus_id": 3122354, "doc_id": "3122354", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "The influence of the rotor slits on the performance of high speed solid rotor induction machine", "venue": "2016 17th International Conference on Mechatronics Mechatronika (ME)", "year": 2016 }, { "abstract": "This chapter begins with a description of different distributed generation (DG) technologies. These are presented from the point of view of their working principle and their way of connecting to the network. An introduction is also given to the load flow problem in DG systems. The different types of nodes are defined and the problem equations are formulated. The network connection of DG involves a change in the control of the system and the quality of the electrical power. In some cases, this connection leads to a deterioration of the quality indices of electric power. In other cases, it may serve to improve these indices. So, this chapter includes a section in which the impact of DG on the quality of electric power is analyzed. The last section is devoted to present and analyze different control strategies of the inverters that are used as interface for the connection between DG and network.", "author_names": [ "Patricio Salmeron Revuelta" ], "corpus_id": 112413429, "doc_id": "112413429", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "8 Distributed Generation", "venue": "", "year": 2016 } ]

[ { "abstract": "Various forms of light therapy have been practiced around the world for many years. Among them the laser therapy has experienced a prosperous development in recent years. More and more laser equipment has been used in this field. In this study, we present an optical pumped vertical external cavity surface emitting laser (OP VECSEL) system using semiconductor gain chip as the lasering material. Through carefully design of the semiconductor gain chip structure, the fundamental and frequency doubled laser emitting wavelength can be set to the range of 1040 1160nm and 520nm 580nm which is the mainly laser tissue interact wavelength range for laser therapy. In a flat concave short cavity laser assembly test, the maximum fundamental frequency output power of the system is 1.6W using a 2% output coupler. Through a frequency doubling crystal, the continuous output power of the yellow green light can achieve 24mW.", "author_names": [ "Jonathan Li", "Chao Wang", "Xin Wei", "Chuanchuan Li" ], "corpus_id": 227075302, "doc_id": "227075302", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "530 580nm optical pumped vertical external cavity surface emitting lasers for laser therapy", "venue": "Applied Optics and Photonics China", "year": 2020 }, { "abstract": "We demonstrate 0.7W cw output power at 520nm from an intracavity frequency doubled optically pumped semiconductor disk laser at room temperature. High beam quality and optical conversion efficiency of 10% has been achieved.", "author_names": [ "S Lutgen", "Michael Kuehnelt", "Ulrich Steegmueller", "Peter Brick", "T F Albrecht", "Wolfgang Reill", "Johann Luft", "Bernadette Kunert", "S Reinhard", "Kerstin Volz", "Wolfgang Stolz" ], "corpus_id": 111094337, "doc_id": "111094337", "n_citations": 21, "n_key_citations": 0, "score": 1, "title": "Green semiconductor disk laser with 0.7W cw output power", "venue": "SPIE OPTO", "year": 2005 }, { "abstract": "We demonstrate 0.7W cw output power at 520nm from an intracavity frequency doubled Optically Pumped Semiconductor Disk Laser at room temperature. High beam quality and optical conversion efficiency of 10% has been achieved.", "author_names": [ "S Lutgen", "Michael Kuehnelt", "Ulrich Steegmueller", "Peter Brick", "T F Albrecht", "Wolfgang Reill", "Johann Luft", "Werner Spath", "Bernadette Kunert", "S Reinhard", "Kerstin Volz", "Wolfgang Stolz" ], "corpus_id": 109402375, "doc_id": "109402375", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "0.7W Green Frequency Doubled Semiconductor Disk Laser", "venue": "", "year": 2005 }, { "abstract": "oped room temperature blue and 'green' vertical cavity surface emitting lasers (VCSELs) \"for the first time, by current injection\" using nitride semiconductor technology for the active region [Daiji Kasahara et al, Appl. Phys. Express, vol4, p072103, 2011] The thresholds for some of the blue devices (451nm wavelength) and 'green' devices (503nm wavelength, actually more blue green, with true green starting at longer than 520nm) were measured, respectively, as 3.0 and 28kA/cm for current density (assuming uniform injection of 1.5 and 22mA over current aperture) and 3.3V and 6.3V for forward voltage. The current apertures for the blue and 'green' devices were 8mm and 10mm, respectively. While the blue device was subjected to continuouswave (CW) operation, the more challenging green device was only tested under pulsed operation (width/period 1/500msec) The maximum output power for the blue device was 0.7mW at 11mA. Within the limitations of the pulsed test set up, the maximum green output power is estimated at more than 0.8mW. The epitaxial material structures were grown on c plane gallium nitride (GaN) substrates using metal organic chemical vapor deposition (MOCVD) The active region consisted of indium gallium nitride (InGaN) wells in GaN barriers. Further processing to make the VCSEL (Figure 1) consisted of a series of steps involving lithography, sputtering, inductively couple plasma (ICP) reactive ion etching, wafer bonding, and chemical mechanical polishing (CMP) First, a current aperture was patterned, followed by application of an indium tin oxide (ITO) transparent conducting contact and current spreading layer, then an electrode around the current aperture. The backside mirror consisted of silicon dioxide/niobium pentoxide (SiO2/Nb2O5) layer pairs as a distributed Bragg reflector (DBR) The structure was then flipped and bonded onto a highly conductive silicon substrate. The GaN substrate and n type layer were then removed/thinned to create suitable cavities before the n type contact and another SiO2/Nb2O5 DBR. Further characterization of the devices involved looking at spectra below, near and above threshold and at the near field emission patterns. The 'green' device shifts its wavelength by about 4nm, going from 499nm to 503nm, in moving from spontaneous to stimulated emission. The researchers report: \"This abnormal behavior of the laser emission peak may be due to refractive index changes induced by thermal effects. The characteristics of GaN based Technology focus: Nitride lasers", "author_names": [], "corpus_id": 208522794, "doc_id": "208522794", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Nichia has made a VCSEL laser emitting blue light in continuous wave mode with power output of 0 7 mW at an injection current of 11 mA", "venue": "", "year": 2011 }, { "abstract": "We present the study on the dynamics of a semiconductor laser with a tunable Fabry Perot filter and a ring single mode fiber based long cavity. Theoretically and experimentally, we analyse dynamical regimes of the laser in various operation regimes, including stable and chaotic dynamics and the formation of coherent structures. The laser coherence build up is studied during the turn on, as well as different scenarios of coherence deterioration in such lasers are examined.", "author_names": [ "Svetlana Slepneva", "Amy Roche", "U Gouda", "Alexander Pimenov", "Anton Kovalev", "M Marconi", "M Giudici", "Evgeny A Viktorov", "Andrei G Vladimirov", "Guillaume Huyet" ], "corpus_id": 229311196, "doc_id": "229311196", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Nonlinear Dynamics in a Long Cavity Semiconductor Laser", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "We demonstrate generation of \"droplet\" Bessel beams using semiconductor laser and an axicon with rounded tip. Interference of Bessel and Gaussian wave fronts leads to cancellation of side lobes of Bessel beam.", "author_names": [ "S H Abdulrazak", "D V Chistyakov", "Sergey N Losev", "V Yu Myl'nikov", "Yu M Zadiranov", "N G Deryagin", "Vladislav V Dudelev", "Vladimir I Kuchinskii", "Grigorii S Sokolovskii" ], "corpus_id": 229308390, "doc_id": "229308390", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Cancellation of side lobes in \"droplet\" Bessel beams generated with semiconductor laser", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "To reduce measurement error of laser thickness gauges and to provide reasons for the choice of acceptance angle for receiving the signal from the controlled surface, the value of a laser emitter signal was studied as the signal was reflected from the laser indicated spot on the rough surface of metal roll. The measurements were taken at different wavelengths. The position of the reflected signal receiver was being changed relative to the normal to the controlled surface.", "author_names": [ "V I Shlychkov" ], "corpus_id": 229308463, "doc_id": "229308463", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Application of semiconductor laser emitters to thickness measurements", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "We demonstrate a room temperature, continuous wave laser source providing 1 THz output by difference frequency generation in a periodically poled lithium niobate crystal using two serially connected similar semiconductor disk laser chips in one cavity for power scalability.", "author_names": [ "Heyang Guoyu", "Ksenia A Fedorova", "Christian Kriso", "Matthias Wichmann", "F Zhang", "Wolfgang Stolz", "Arash Rahimi-Iman" ], "corpus_id": 229307896, "doc_id": "229307896", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Room Temperature CW THz Emitting Two Chip Semiconductor Disk Laser", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "For the first time, an analysis of a series of laser heterostructures with different active region designs and cavity parameters is performed to solve the problem of generating sub ns pulses with different characteristics (duration and peak optical power) For the study, semiconductor lasers of a mesa stripe design with an aperture width of 100 mm and current pulses with a pulse base from 1 ns to 3 ns and an amplitude up to 50 A were used. It is shown that the minimum pulse width of the first relaxation peak was 50 ps at a peak power of up to 3 W with a combination of such parameters as a single QW, an optical confinement factor of 1.23 and a cavity length of 700 mm. The use of multiple quantum well heterostructures provided the generation of pulses with a peak power of up to 30 W and a pulse width of 100 200 ps.", "author_names": [ "Sergey O Slipchenko", "Alexsandr Podoskin", "Vyacheslav S Golovin", "Viktor Shamakhov", "I N Arsentiev", "L S Vaviliva", "Andrey V Lyutetskiy", "Dmitriy N Nikolaev", "Nikita A Pikhtin", "P S Kopev" ], "corpus_id": 229311532, "doc_id": "229311532", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of semiconductor lasers for generation of high power sub ns laser pulses in the gain switching mode", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 }, { "abstract": "We present a compact picosecond hybrid laser for satellite ranging based on semiconductor DFB laser oscillator, Yb doped fiber and Nd:YVO4 bulk amplifiers. The output of 2.1 mJ, 25 ps pulses at 1 kHz repetition rate, 532 nm second harmonic wavelength with a near diffraction limited beam quality M2<1.5 was obtained, limits of peak power scaling in each amplifier were investigated.", "author_names": [ "I A Gorbunov", "O V Kulagin" ], "corpus_id": 229307324, "doc_id": "229307324", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Picosecond hybrid laser based on semiconductor DFB laser, fiber and Nd:YVO4 amplifiers limits of output peak power scaling", "venue": "2020 International Conference Laser Optics (ICLO)", "year": 2020 } ]

[ { "abstract": "We study the influence of surface passivating ligands on the optical and structural properties of zinc blende CdSe nanoplatelets. Ligand exchange of native oleic acid with aliphatic thiol or phosphonic acid on the surface of nanoplatelets results in a large shift of exciton transition energy for up to 240 meV. Ligand exchange also leads to structural changes (strain) in the nanoplatelet's core analysed by wide angle X ray diffraction. By correlating the experimental data with theoretical calculations we demonstrate that the exciton energy shift is mainly caused by the ligand induced anisotropic transformation of the crystalline structure altering the well width of the CdSe core. Further the exciton reduced mass in these CdSe quantum wells is determined by a new method and this agrees well with the expected values substantiating that ligand strain induced changes in the colloidal quantum well thickness are responsible for the observed spectral shifts. Our findings are important for theoretical modeling of other anisotropically strained systems and demonstrate an approach to tune the optical properties of 2D semiconductor nanocrystals over a broad region thus widening the range of possible applications of AIIBVI nanoplatelets in optics and optoelectronics.", "author_names": [ "Artsiom Antanovich", "Alexander W Achtstein", "A S Matsukovich", "Anatol V Prudnikau", "Prashant Bhaskar", "Vladimir N Gurin", "Michael Molinari", "Mikhail V Artemyev" ], "corpus_id": 206105308, "doc_id": "206105308", "n_citations": 34, "n_key_citations": 1, "score": 0, "title": "A strain induced exciton transition energy shift in CdSe nanoplatelets: the impact of an organic ligand shell.", "venue": "Nanoscale", "year": 2017 }, { "abstract": "We use continuum mechanics to calculate an entire least energy pathway of membrane fusion, from stalk formation, to pore creation, and through fusion pore enlargement. The model assumes that each structure in the pathway is axially symmetric. The static continuum stalk structure agrees quantitatively with experimental stalk architecture. Calculations show that in a stalk, the distal monolayer is stretched and the stored stretching energy is significantly less than the tilt energy of an unstretched distal monolayer. The string method is used to determine the energy of the transition barriers that separate intermediate states and the dynamics of two bilayers as they pass through them. Hemifusion requires a small amount of energy independently of lipid composition, while direct transition from a stalk to a fusion pore without a hemifusion intermediate is highly improbable. Hemifusion diaphragm expansion is spontaneous for distal monolayers containing at least two lipid components, given sufficiently negative diaphragm spontaneous curvature. Conversely, diaphragms formed from single component distal monolayers do not expand without the continual injection of energy. We identify a diaphragm radius, below which central pore expansion is spontaneous. For larger diaphragms, prior studies have shown that pore expansion is not axisymmetric, and here our calculations supply an upper bound for the energy of the barrier against pore formation. The major energy requiring deformations in the steps of fusion are: widening of a hydrophobic fissure in bilayers for stalk formation, splay within the expanding hemifusion diaphragm, and fissure widening initiating pore formation in a hemifusion diaphragm.", "author_names": [ "Rolf J Ryham", "Thomas Klotz", "Lihan Yao", "Fredric S Cohen" ], "corpus_id": 32376557, "doc_id": "32376557", "n_citations": 45, "n_key_citations": 5, "score": 0, "title": "Calculating Transition Energy Barriers and Characterizing Activation States for Steps of Fusion.", "venue": "Biophysical journal", "year": 2016 }, { "abstract": "Abstract Germany has set ambitious policies for increasing renewable energy shares and decommissioning nuclear energy, but there are certain scientific gaps on how this transition should occur, especially when considering all energy sectors. The purpose of this study is to advance the knowledge of transitioning the German energy system to 100% renewable energy towards 2050. Taking into consideration renewable resource potentials, energy system costs and primary energy supply this study develops a path for transitioning the German energy system within the heating, industrial, transport and electricity sectors. The analysis demonstrates that it is possible to carry out this transition from a technical and economic perspective with some measures being vital for achieving this ambition in a cost effective manner. The most significant challenge in this transition is regarding resource potentials where especially biomass resources are constrained and under pressure. Finally, the most influential measures for achieving the renewable transition are discussed.", "author_names": [ "Kenneth Hansen", "Brian Vad Mathiesen", "Iva Ridjan Skov" ], "corpus_id": 115288313, "doc_id": "115288313", "n_citations": 140, "n_key_citations": 1, "score": 1, "title": "Full energy system transition towards 100% renewable energy in Germany in 2050", "venue": "Renewable and Sustainable Energy Reviews", "year": 2019 }, { "abstract": "Owing to its low excitation energy and long radiative lifetime, the first excited isomeric state of thorium 229, 229mTh, can be optically controlled by a laser1,2 and is an ideal candidate for the creation of a nuclear optical clock3, which is expected to complement and outperform current electronic shell based atomic clocks4. A nuclear clock will have various applications such as in relativistic geodesy5, dark matter research6 and the observation of potential temporal variations of fundamental constants7 but its development has so far been impeded by the imprecise knowledge of the energy of 229mTh. Here we report a direct measurement of the transition energy of this isomeric state to the ground state with an uncertainty of 0.17 electronvolts (one standard deviation) using spectroscopy of the internal conversion electrons emitted in flight during the decay of neutral 229mTh atoms. The energy of the transition between the ground state and the first excited state corresponds to a wavelength of 149.7 3.1 nanometres, which is accessible by laser spectroscopy through high harmonic generation. Our method combines nuclear and atomic physics measurements to advance precision metrology, and our findings are expected to facilitate the application of high resolution laser spectroscopy on nuclei and to enable the development of a nuclear optical clock of unprecedented accuracy. The transition energy of the first excited state of 229Th to the ground state is determined through the measurement of internal conversion electrons to correspond to a wavelength of 149.7 3.1 nanometres.", "author_names": [ "Benedict Seiferle", "Lars von der Wense", "Pavlo V Bilous", "Ines Amersdorffer", "Christoph Lemell", "Florian Libisch", "Simon Stellmer", "Thorsten Schumm", "Christoph E Dullmann", "Adriana P'alffy", "Peter G Thirolf" ], "corpus_id": 155090121, "doc_id": "155090121", "n_citations": 65, "n_key_citations": 1, "score": 0, "title": "Energy of the 229Th nuclear clock transition", "venue": "Nature", "year": 2019 }, { "abstract": "Abstract Is an energy transition currently in progress, where renewable energy sources are replacing fossil fuels? Previous changes in the proportion of energy produced by various sources such as in the nineteenth century when coal surpassed biomass in providing the largest share of the global energy supply and in the twentieth century when petroleum overtook coal could more accurately be characterized as energy additions rather than transitions. In both cases, the use of the older energy source continued to grow, despite rapid growth in the new source. Evidence from contemporary trends in energy production likewise suggest that as renewable energy sources compose a larger share of overall energy production, they are not replacing fossil fuels but are rather expanding the overall amount of energy that is produced. We argue that although it is reasonable to expect that renewables will come to provide a growing share of the global energy supply, it is misleading to characterize this growth in renewable energy as a \"transition\" and that doing so could inhibit the implementation of meaningful policies aimed at reducing fossil fuel use.", "author_names": [ "Richard York", "Shannon Elizabeth Bell" ], "corpus_id": 134764110, "doc_id": "134764110", "n_citations": 88, "n_key_citations": 1, "score": 0, "title": "Energy transitions or additions?", "venue": "Energy Research Social Science", "year": 2019 }, { "abstract": "In this paper, intersubband transition energy is computed for core shell (normal and inverted) quantum dots (CSQD) of cubic and spherical geometries by solving time independent Schrodinger equation using finite difference technique. Sparse, structured Hamiltonian matrices of order N3 x N3 for cubic and N x N for spherical dots are produced considering N discrete points in spatial direction. The matrices are diagonalized to obtain eigenstates for electrons. Computed results for the lowest three eigenstates and intersubband transitions are shown for different structural parameters taking GaAs/AlxGa1 xAs based CSQD as example. Transition energy decreases with increase in core thickness. When compared, spherical CSQDs show higher transition energy between two subbands than cubic CSQDs of similar size and same material composition. Also, in inverted configuration, transition energy decreases for a cubic dot while increases for a spherical dot as core size is increased. Wide tuning range for intersubband transition by tailoring dot dimensions indicates important applications for optical emitters/detectors.", "author_names": [ "Arpan Deyasi", "S Bhattacharyya", "Nikhil Ranjan Das" ], "corpus_id": 119805647, "doc_id": "119805647", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Computation of intersubband transition energy in normal and inverted core shell quantum dots using finite difference technique", "venue": "", "year": 2013 }, { "abstract": "The 1s2s (3)S(1) 1s(2) (1)S(0) relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron cyclotron resonance ion source, has been measured using a double flat crystal x ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference free) measurements in the x ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy) This value is the most accurate, reference free measurement done for such a transition and is in good agreement with recent QED predictions.", "author_names": [ "Pedro Amaro", "Sophie Schlesser", "Mauro Guerra", "E-O Le Bigot", "J M Isac", "Pascal Travers", "Jose Paulo Santos", "Csilla I Szabo", "Alexandre Gumberidze", "Paul Indelicato" ], "corpus_id": 32682855, "doc_id": "32682855", "n_citations": 35, "n_key_citations": 3, "score": 0, "title": "Absolute measurement of the relativistic magnetic dipole transition energy in heliumlike argon.", "venue": "Physical review letters", "year": 2012 }, { "abstract": "Abstract The effects of the doping level and the operating current on the transition energy of InGaN/GaN QW diodes have been studied through the self consistent solution of the Schrodinger and Poisson equations. Broad change in the transition energy is observed due to the doping variation. With increase in the current density the emission peak shifts toward higher energy. This shift, which is a major disadvantage of the lighting devices, is reduced significantly by increasing the doping concentration.", "author_names": [ "Siddhartha Panda", "Dipankar Biswas" ], "corpus_id": 121258329, "doc_id": "121258329", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Effects of doping concentration on the transition energy of InGaN/GaN quantum well diodes", "venue": "", "year": 2013 }, { "abstract": "", "author_names": [ "Pengbiao Geng", "Shasha Zheng", "Hao Tang", "Rongmei Zhu", "Li Zhang", "Shuai Cao", "Huaiguo Xue", "Huan Pang" ], "corpus_id": 103574665, "doc_id": "103574665", "n_citations": 375, "n_key_citations": 0, "score": 0, "title": "Transition Metal Sulfides Based on Graphene for Electrochemical Energy Storage", "venue": "", "year": 2018 }, { "abstract": "The calculation of vertical electronic transition energies of molecular systems in solution with accurate quantum mechanical methods requires the use of approximate and yet reliable models to describe the effect of the solvent on the electronic structure of the solute. The polarizable continuum model (PCM) of solvation represents a computationally efficient way to describe this effect, especially when combined with coupled cluster (CC) methods. Two formalisms are available to compute transition energies within the PCM framework: State Specific (SS) and Linear Response (LR) The former provides a more complete account of the solute solvent polarization in the excited states, while the latter is computationally very efficient (i.e. comparable to gas phase) and transition properties are well defined. In this work, I review the theory for the two formalisms within CC theory with a focus on their computational requirements, and present the first implementation of the LR PCM formalism with the coupled cluster singles and doubles method (CCSD) Transition energies computed with LR and SS CCSD PCM are presented, as well as a comparison between solvation models in the LR approach. The numerical results show that the two formalisms provide different absolute values of transition energy, but similar relative solvatochromic shifts (from nonpolar to polar solvents) The LR formalism may then be used to explore the solvent effect on multiple states and evaluate transition probabilities, while the SS formalism may be used to refine the description of specific states and for the exploration of excited state potential energy surfaces of solvated systems.", "author_names": [ "Marco Caricato" ], "corpus_id": 17643282, "doc_id": "17643282", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "A comparison between state specific and linear response formalisms for the calculation of vertical electronic transition energy in solution with the CCSD PCM method.", "venue": "The Journal of chemical physics", "year": 2013 } ]

[ { "abstract": "Nearly lattice matched or pseudomorphically grown III V semiconductor quantum structures such as quantum wells, quantum dots, and superlattices can provide high degree of flexibility in terms cutoff wavelength range. In this presentation, we describe the development of long wavelength quantum well infrared photodetectors (QWIPs) for imaging spectrometer applications and quantum dot infrared photodetectors (QDIPs) for long wavelength applications. In addition, III V semiconductors offer a highly effective platform for the development of sophisticated heterostructure based MWIR and LWIR detectors, as exemplified by the high performance double heterstructure (DH) nBn, XBn, and type II superlattice infrared detectors. A key enabling design element is the unipolar barrier, which is used to implement the complementary barrier infra red detector (CBIRD) design for increasing the collection efficiency of photo generated carriers, and reducing dark current generation without impeding photocurrent flow. Heterostructure superlattice detectors that make effective use of unipolar barriers have demonstrated strong reduction of generation recombination (G R) dark current due to Shockley Read Hall (SRH) processes.", "author_names": [ "Sarath D Gunapala", "David Z Ting", "Alexander Soibel", "Sam Keo", "Sir Rafol", "Jason Mumolo", "John K Liu", "Cory Hill", "Arezou Khoshakhlagh", "Linda Hoglund", "Edward Luong" ], "corpus_id": 124916257, "doc_id": "124916257", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Development of Quantum Well, Quantum Dot, and Antimonide Superlattice Infrared Photodetectors", "venue": "", "year": 2014 }, { "abstract": "While physical properties of ideal antimonide superlattices (ASL) indicate that they should significantly outperform mercury cadmium telluride (MCT) based infrared photodiodes for low dark current applications in the long and very long wave infrared (LWIR and VLWIR) this potential has not yet been fully realized. Even though measured Auger and tunneling rates in ASL's are reduced as predicted, overall carrier lifetimes remain much shorter, and dark currents much higher than expected. The large carrier losses are the result of defects in the ASL structure, with contributions measured from large bulk defects and surface channels along mesa sidewalls, and the remaining component believed to be due to midgap states. In this presentation we report on several studies of epitaxial growth parameters and their influence on defect formation. X ray photoelectron spectroscopy analysis of oxide desorption from GaSb substrates shows the presence of both antimony and gallium oxides, along with their decomposition and desorption behavior with anneal temperature. A study of buffer growth shows that defect density and size are critically dependent on growth temperature, with an optimal growth window between 480 and 500 degC. Side by side GaSb buffer growths on vicinal (100) 1 deg (111) and flat (100) substrates show that while growing on vicinal material can suppress mound formation, it does not yield epilayers as flat as can be obtained on (100) substrates grown under optimal conditons. Finally, the ratio of As to In flux during superlattice growth can be used to tune the lattice parameter both above and below that of GaSb, with strain related defects appearing when the mismatch reaches roughly 0.1%", "author_names": [ "Edward H Aifer", "Eric M Jackson", "Brian R Bennett", "Igor Vurgaftman", "J R Meyer", "Glenn G Jernigan" ], "corpus_id": 99001128, "doc_id": "99001128", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Suppression of Bulk Defects in Antimonide Superlattice Infrared Photodiodes", "venue": "", "year": 2002 }, { "abstract": "Mid infrared (MIR) silicon photonics holds the potential for realizing next generation ultracompact spectroscopic systems for applications in gas sensing, defense, and medical diagnostics. The direct epitaxial growth of antimonide based compound semiconductors on silicon provides a promising approach for extending the wavelength of silicon photonics to the longer infrared range. This paper reports on the fabrication of a high performance MIR photodetector directly grown onto silicon by molecular beam epitaxy. The device exhibited an extended cutoff wavelength at ~5.5 mm and a dark current density of 1.4 x 10 2 A/cm2 under 100 mV reverse bias at 200 K. A responsivity of 0.88 A/W and a specific detectivity in the order of 1.5 x 1010 Jones was measured at 200 K under 100 mV reverse bias operation. These results were achieved through the development of an innovative structure which incorporates a type II InAs/InAsSb superlattice based barrier nBn photodetector grown on a GaSb on silicon buffer layer. The difficulties in growing GaSb directly on silicon were overcome using a novel growth procedure consisting of an efficient AlSb interfacial misfit array, a two step growth temperature procedure and dislocation filters resulting in a low defect density, antiphase domain free GaSb epitaxial layer on silicon. This work demonstrates that complex superlattice based MIR photodetectors can be directly integrated onto a Si platform, which provides a pathway toward the realization of new, high performance, large area focal plane arrays and mid infrared integrated photonic circuits.", "author_names": [ "Evangelia Delli", "V Letka", "Peter Hodgson", "Eva Repiso", "Jonathan P Hayton", "Adam P Craig", "Qi Lu", "Richard Beanland", "Anthony Krier", "Andrew R J Marshall", "Peter J Carrington" ], "corpus_id": 108287670, "doc_id": "108287670", "n_citations": 26, "n_key_citations": 0, "score": 1, "title": "Mid Infrared InAs/InAsSb Superlattice nBn Photodetector Monolithically Integrated onto Silicon", "venue": "", "year": 2019 }, { "abstract": "Type II InAs/GaSb Superlattice (SL) a system of multi interacting quantum wells was first introduced by Nobel Laureate L. Esaki in the 1970s. Since then, this low dimensional system has drawn a lot of attention for its attractive quantum mechanics properties and its grand potential for the emergence into the application world, especially in infrared detection. In recent years, Type II InAs/GaSb superlattice photo detectors have experienced significant improvements in material quality, structural designs and imaging applications which elevated the performances of Type II InAs/GaSb superlattice photodetectors to a comparable level to the state of the art Mercury Cadmium Telluride. We will present in this talk the current status of the state of the art Type II superlattice photodetectors and focal plane arrays, and the future outlook for this material system.", "author_names": [ "Manijeh Razeghi", "Binh Minh Nguyen", "Pierre Yves Delaunay", "Edward Kwei Wei Huang", "Siamak Abdollahi Pour", "Paritosh Manukar", "Simeon I Bogdanov" ], "corpus_id": 121680308, "doc_id": "121680308", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "State of the art Type II antimonide based superlattice photodiodes for infrared detection and imaging", "venue": "Optical Engineering Applications", "year": 2009 }, { "abstract": "Authors discuss how anion incorporation was controlled during the epitaxial growth process to develop InAs/GaInSb superlattice (SL) materials for very long wavelength infrared applications. A SL structure of 47.0 A InAs/21.5 A Ga0.75In0.25Sb was selected to create a very narrow band gap. Although a molecular beam epitaxy growth developed can produce a strain balanced ternary SL structure with a precisely controlled band gap around 50 meV, the material quality of grown SL layers is particularly sensitive to growth defects formed during an anion incorporation process. Since Group III antisites are the dominant structural defects responsible for the low radiative efficiencies, the authors focus on stabilizing III/V incorporation during SL layer growth by manipulating the growth surface condition for a specific anion cracking condition. The optimized ternary SL materials produced an overall strong photoresponse signal with a relatively sharp band edges and a high mobility of ~10,000 cm2/V s that is important for developing infrared materials.", "author_names": [ "H J Haugan", "Gail J Brown", "Said Elhamri", "Larry Grazulis" ], "corpus_id": 95531157, "doc_id": "95531157", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Control of anion incorporation in the molecular beam epitaxy of ternary antimonide superlattices for very long wavelength infrared detection", "venue": "", "year": 2015 }, { "abstract": "Infrared detectors are very important technological tools for many different applications. Infrared detectors have existed as far back as the late 1700s but received a tremendous push 200 years later during World War II. Both thermal and photon based infrared detectors have had significant advancements with many different varieties becoming available with varying degrees of sensitivity, speed, and wavelength sensitivity. One of the best performing technologies is based on Mercury Cadmium Telluride. However, it still has limitations with regard to low operating temperature, material yield and processing difficulties. A newer material technology known as type II indium arsenide/gallium antimonide strain layered superlattice has received much attention for its potential superior performance from lower dark current, mature III V material fabrication techniques, and design versatility. However, superior", "author_names": [ "Stephen A Myers" ], "corpus_id": 138898599, "doc_id": "138898599", "n_citations": 1, "n_key_citations": 1, "score": 0, "title": "Mid Wave and Long Wave Single Uni polar Barrier Infrared Detectors Based on Antimonide Material Systems", "venue": "", "year": 2013 }, { "abstract": "Significant progress has been achieved in the antimonide based type II superlattices since the analysis by Smith and Mailhiot in 1987 first pointed out their advantages for infrared detection. In the long wavelength infrared (LWIR) type II InAs/Ga(In)Sb superlattices have been shown theoretically to have reduced Auger recombination and suppressed band to band tunneling. Suppressed tunneling in turn allows for higher doping in the absorber, which has led to reduced diffusion dark current. The versatility of the antimonide material system, with the availability of three different types of band offsets, provides great flexibility in device design. Heterostructure designs that make effective use of unipolar barriers have demonstrated strong reduction of generation recombination (G R) dark current. As a result, the dark current performance of antimonide superlattice based single element LWIR detectors is now approaching that of the state of the art MCT detector. To date, the antimonide superlattices still have relatively short carrier lifetimes; this issue needs to be resolved before type II superlattice infrared detectors can achieve their true potential. The antimonide material system has relatively good mechanical robustness when compared to II VI materials; therefore FPAs based on type II superlattices have potential advantages in manufacturability. Improvements in substrate quality and size, and reliable surface leakage current suppression methods, such as those based on robust surface passivation or effective use of unipolar barriers, could lead to high performance large format LWIR focal plane arrays.", "author_names": [ "David Z Ting", "Alexander Soibel", "Jean Nguyen", "Linda Hoglund", "Arezou Khoshakhlagh", "Sir Rafol", "Sam Keo", "Anna Liao", "Jason Mumolo", "John K Liu", "Sarath D Gunapala" ], "corpus_id": 122112621, "doc_id": "122112621", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Type II superlattice barrier infrared detector", "venue": "Optical Engineering Applications", "year": 2011 }, { "abstract": "Authors discuss how anion incorporation was controlled during the epitaxial growth process to develop InAs/GaInSb superlattice (SL) materials for very long wavelength infrared applications. A SL structure of 47.0 A InAs/21.5 A Ga0.75In0.25Sb was selected to create a very narrow band gap. Although a molecular beam epitaxy growth developed can produce a strain balanced ternary SL structure with a precisely controlled band gap around 50 meV, the material quality of grown SL layers is particularly sensitive to growth defects formed during an anion incorporation process. Since Group III antisites are the dominant structural defects responsible for the low radiative efficiencies, the authors focus on stabilizing III/V incorporation during SL layer growth by manipulating the growth surface condition for a specific anion cracking condition. The optimized ternary SL materials produced an overall strong photoresponse signal with a relatively sharp band edges and a high mobility of 10,000 cm/V s that is important for developing infrared materials. 2015 Elsevier B.V. All rights reserved.", "author_names": [ "H J Haugan", "G J Brown", "Said Elhamri", "Larry Grazulis" ], "corpus_id": 210843681, "doc_id": "210843681", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CONTROL OF ANION IN CORPORATION IN THE MOLECULAR BEAM EPITAXY OF TERNARY ANTIMONIDE SUPERLATTICES FOR VERY LONG WAVELENGTH INFRARED DETECTION (POSTPRINT)", "venue": "", "year": null }, { "abstract": "The properties of Sb based III V semiconductor compounds for optoelectronic applications in the mid wavelength infrared (MWIR) and long wavelength infrared (LWIR) range were reviewed. The growths of the Sb based binary, ternary and quaternary were studied by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) The structural, optical and electrical characterizations were carried out. Focal plane array, photoconductors and photodiodes were fabricated for the MWIR and LWIR range. Doublehetero structure (DH) multi quantum well (MQW) and strained superlattice (SSL) lasers in the 3 5 m m range were fabricated. InAs GaSb type II superlattices were designed, grown and fabricated into photodetectors for the MWIR and LWIR range.", "author_names": [ "Manijeh Razeghi" ], "corpus_id": 54868264, "doc_id": "54868264", "n_citations": 46, "n_key_citations": 3, "score": 0, "title": "Overview of antimonide based III V semiconductor epitaxial layers and their applications at the center for quantum devices", "venue": "", "year": 2003 }, { "abstract": "The antimonide superlattice infrared detector technology program was established to explore new infrared detector materials and technology. The ultimate goal is to enhance the infrared sensor system capability and meet challenging requirements for many applications. Certain applications require large format focal plane arrays (FPAs) for a wide field of view. These FPAs must be able to detect infrared signatures at long wavelengths, at low infrared background radiation, and with minimal spatial cross talk. Other applications require medium format pixel, co registered, dual band capability with minimal spectral cross talk. Under the technology program, three leading research groups have focused on device architecture design, high quality material growth and characterization, detector and detector array processing, hybridization, testing, and modeling. Tremendous progress has been made in the past few years. This is reflected in orders of magnitude reduction in detector dark current density and substantial increase in quantum efficiency, as well as the demonstration of good quality long wavelength infrared FPAs. Many technical challenges must be overcome to realize the theoretical promise of superlattice infrared materials. These include further reduction in dark current density, growth of optically thick materials for high quantum efficiency, and elimination of FPA processing related performance degradation. In addition, challenges in long term research and development cost, superlattice material availability, FPA chip assembly availability, and industry sustainability are also to be met. A new program was established in 2009 with a scope that is different from the existing technology program. Called Fabrication of Superlattice Infrared FPA (FastFPA) this 4 year program sets its goal to establish U.S. industry capability of producing high quality superlattice wafers and fabricating advanced FPAs. It uses horizontal integration strategy by leveraging existing III V industry resources and taking advantage of years of valuable experiences amassed by the HgCdTe FPA industry. By end of the program span, three sets of FPAs will be demonstrated a small format long wave FPA, a large format long wave FPA, and a medium format dual band FPA at long wave and mid wave infrared.", "author_names": [ "Lucy Zheng", "Meimei Tidrowb", "Leslie Aitchesonb", "Jerry O'Connorc" ], "corpus_id": 26691412, "doc_id": "26691412", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "1 1 2010 Developing High Performance III V Superlattice IRFPAs for Defense Challenges and Solutions", "venue": "", "year": 2016 } ]

[ { "abstract": "Hybrid perovskite MAPbCl3 is considered to be one of the most promising candidates applied in visible blind UV photo detectors due to its outstanding optoelectronic properties. It is proved that the MAPbCl3 single crystal is more excellent than its polycrystalline counterpart because of its fewer defects and grain boundaries. When referring to a single crystal, the crystal orientation or crystal structure anisotropy is an inevitable topic, because structure anisotropy can affect or decide the optoelectronic properties of single crystals. In this study, both cubic and triangular prism MAPbCl3 single crystals with (100) and (110) crystallographic planes were successfully grown from mixed solutions. The crystal growth process, crystal structure and optical absorption were investigated. Moreover, by fabricating metal semiconductor metal (MSM) photo detectors using Au interdigital electrodes on both (100) and (110) planes, the optoelectronic anisotropy was explored by comparing photocurrents, responsivity, external quantum efficiency and detectivity. According to the crystal structure and calculated charge density, the optoelectronic anisotropy in the MAPbCl3 single crystal was revealed.", "author_names": [ "Xiaohua Cheng", "Lin Jing", "Yingge Zhao", "Songjie Du", "Jianxu Ding", "Tian-liang Zhou" ], "corpus_id": 139171852, "doc_id": "139171852", "n_citations": 35, "n_key_citations": 0, "score": 1, "title": "Crystal orientation dependent optoelectronic properties of MAPbCl3 single crystals", "venue": "", "year": 2018 }, { "abstract": "As one type of organic inorganic hybrid lead halide perovskites, MAPbX3 has attracted immense interests in applications of optoelectronic devices because of its remarkable properties. However, the", "author_names": [ "Xiaohua H Cheng", "Lin Jing", "Ye Yuan", "Songjie Du", "Jun Zhang", "Xiaoyuan Zhan", "Jianxu Ding", "Hao Yu", "Guodong Shi" ], "corpus_id": 104412469, "doc_id": "104412469", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Fe2+/Fe3+ Doped into MAPbCl3 Single Crystal: Impact on Crystal Growth and Optical and Photoelectronic Properties", "venue": "", "year": 2019 }, { "abstract": "Since their first appearance, organic inorganic perovskite absorbers have been capturing the attention of the scientific community. While high efficiency devices highlight the importance of band level alignment, very little is known on the origin of the strong n doping character observed in the perovskite. Here, by means of a highly accurate photoemission study, we shed light on the energy alignment in perovskite based devices. Our results suggest that the interaction with the substrate may be the driver for the observed doping in the perovskite samples.", "author_names": [ "Marco Caputo", "N Cefarin", "Andrea Radivo", "Nicola Demitri", "Lara Gigli", "Jasper Rikkert Plaisier", "Mirco Panighel", "Giovanni Di Santo", "Sacha Moretti", "Angelo Giglia", "Maurizio Polentarutti", "Filippo De Angelis", "Edoardo Mosconi", "Paolo Umari", "Massimo Tormen", "Andrea Goldoni" ], "corpus_id": 204835871, "doc_id": "204835871", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Electronic structure of MAPbI3 and MAPbCl3: importance of band alignment", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "The local structure of MAPbCl3 has been investigated through the combined use of X ray and neutron pair distribution function (PDF) analysis and computational modeling. The results indicate the presence of a significant level of distortion at the short range, irrespective of the average structure found by diffraction, and this suggests a possible correlation between the type of distortion and the features of the strongest H X bond. The distortion of the octahedra decreases by reducing temperature, but the overall tilting of the octahedral system increases, and such tilting depends on the size of the anion. The comparison of the short range structural data available on the MAPbX3 family strongly indicates a common pattern of the local structural distortion in these systems.", "author_names": [ "Andrea Bernasconi", "Katharine L Page", "Zhenbang Dai", "Liang Z Tan", "Andrew M Rappe", "Lorenzo Malavasi" ], "corpus_id": 104432589, "doc_id": "104432589", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Ubiquitous Short Range Distortion of Hybrid Perovskites and Hydrogen Bonding Role: the MAPbCl3 Case", "venue": "", "year": 2018 }, { "abstract": "Various methods have been developed to optimize the active layer of perovskite solar cells. To date, the introduction of excess PbI2 and chlorine doping are two typical means. Herein, an ion exchange decomposition process was designed to combine these two approaches. In this process, the I Cl exchange and MACl sublimation occurred simultaneously at elevated temperature, resulting in a PbI2 excess, Cl doped perovskite film. This combined strategy could guarantee that as much chlorine as possible was doped into the perovskite crystal lattice, which enables the production of perovskite films with obviously reduced defect density and enhanced carrier diffusion length. Strikingly, the power conversion efficiency of the device is boosted from 17.17% to 20.15%", "author_names": [ "Cui Ping Zhang", "Zhipeng Li", "Juan Liu", "Yunchuan Xin", "Zhipeng Shao", "Guanglei Cui", "Shuping Pang" ], "corpus_id": 103528750, "doc_id": "103528750", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "MAPbCl3 Mediated Decomposition Process to Tune Cl/PbI2 Distribution in MAPbI3 Films", "venue": "", "year": 2018 }, { "abstract": "Recently, perovskite based solar cells have attracted lots of research interest, some of which is in the passivation of perovskite surfaces, particularly the heterojunction based surface passivation. In this study, the optical dynamics of MAPbBr3 single crystals with and without heterojunction passivation were studied systematically by means of a time resolved spectroscopic technique for the first time. The emission lifetime of MAPbBr3 single crystals under two photon (1064 nm) excitation is a few orders of magnitude longer than that measured under one photon (355 nm or 532 nm) excitation. Interestingly, with surface passivation, the lifetime measured at 355 nm excitations could be tuned significantly, whereas the lifetime change under 1064 nm excitations was considerably less. Our results give a direct evidence of surface quench by comparing the lifetimes before and after surface passivation. Furthermore, the results demonstrate that proper MAPbCl3 MAPbBr3 heterojunctions can dramatically reduce the recombination channels in the surface region, which can be potentially useful for perovskite based solar cells, light emitting diodes (LED) and sensitive detectors.", "author_names": [ "Haizhou Lu", "Huotian Zhang", "Sijian Yuan", "Jiao Wang", "Yiqiang Zhan", "Lirong Zheng" ], "corpus_id": 20620702, "doc_id": "20620702", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "An optical dynamic study of MAPbBr3 single crystals passivated with MAPbCl3/I3 MAPbBr3 heterojunctions.", "venue": "Physical chemistry chemical physics PCCP", "year": 2017 }, { "abstract": "", "author_names": [ "Lu Haizhou", "Zhang Huotian", "Yuan Sijian", "Wang Jiao", "Zhang Yiqiang", "Zheng Li-rong" ], "corpus_id": 231071613, "doc_id": "231071613", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "MAPbCl3/I3 MAPbBr3heteroJie He deBu Dong Tai Hua shitaMAPbBr3Dan Jie Jing noGuang Dong Li Xue Yan Jiu", "venue": "", "year": 2017 }, { "abstract": "Hybrid organic inorganic lead halide perovskites are projected as new generation photovoltaic and optoelectronic materials with improved efficiencies. However, their electronic structure so far remains poorly understood, particularly in the orientationally disordered cubic phase. We performed electronic structure investigations using angle resolved photoemission spectroscopy on two prototypical samples (MAPbBr3 and MAPbCl3) in their cubic phase and the results are compared with the calculations within two theoretical models where MA+ is orientationally (1) disordered (MA+ ion is replaced by spherically symmetric Cs+ ion) and (2) ordered (MA oriented along (100) direction) but keeping the symmetry of the unit cell cubic. Degeneracy of the valence bands and behavior of constant energy contours are consistent with Model (1) which supports strongly the disordered nature of the orientation of the MA+ ions in the cubic phase. Band structure calculations also reveals that spin orbit coupling induced Rashba splitting is suppressed by the orientational disorder.", "author_names": [ "Pronoy Nandi", "Chandan Giri", "Vijay Singh", "Luca Petaccia", "Unnikrishnan Manju", "Subhendra D Mahanti", "Dinesh Topwal" ], "corpus_id": 220306641, "doc_id": "220306641", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Probing the Electronic Structure of Hybrid Perovskites in the Orientationally Disordered Cubic Phase.", "venue": "The journal of physical chemistry letters", "year": 2020 }, { "abstract": "Introducing hole/electron transporting and blocking layers is considered to enhance the performance of electronic devices based on organic inorganic hybrid halide perovskite single crystals (PSCs) In many photodiodes, the hole/electron transporting or blocking materials are spin coated or thermal evaporated on PSC to fabricate heterojunctions. However, the heterojunction interfaces due to lattice mismatch between hole/electron, transporting or blocking materials and perovskites easily form traps and cracks, which cause noise and leakage current. Besides, these low mobility transporting layers increase the difficulty of transporting carriers generated by photons to the electrode; hence, they also increase the response time for photo detection. In the present study, MAPbCl3 MAPbBr2.5Cl0.5 heterojunction interfaces were realized by liquid phase epitaxy, in which MAPbBr2.5Cl0.5 PSC acts as an active layer and MAPbCl3 PSC acts as a hole blocking layer (HBL) Our PIN photodiodes with epitaxial MAPbCl3 PSC as HBL show better performance in dark current, light responsivity, stability, and response time than the photodiodes with spin coated organic PCBM as HBL. These results suggest that the heterojunction interface formed between two bulk PSCs with different halide compositions by epitaxy growth is very useful for effectively blocking the injected charges under high external electric field, which could improve the collection of photo generated carriers and hereby enhance the detection performance of the photodiode. Furthermore, the PIN photodiodes made of PSC with epitaxial HBL show the sensitivities of 7.08 mC Gyair 1 cm 2, 4.04 mC Gyair 1 cm 2, and 2.38 mC Gyair 1 cm 2 for 40 keV, 60 keV, and 80 keV X ray, respectively.", "author_names": [ "Yuzhu Pan", "Xuefeng Wang", "Yubing Xu", "Yuwei Li", "Elias Emeka Elemike", "Ahmed Shuja", "Qing Li", "Xiaobing Zhang", "Junli Chen", "Zhiwei Zhao", "Wei Lei" ], "corpus_id": 221567140, "doc_id": "221567140", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Enhanced Performance of Perovskite Single Crystal Photodiodes by Epitaxial Hole Blocking Layer", "venue": "Frontiers in Chemistry", "year": 2020 }, { "abstract": "Mixed halide perovskite (MAPbI3 xClx) solar cells have been widely researched because of their excellent photoelectronic properties. However, Cl doping is difficult to obtain due to the low formation energy and low boiling point of MAPbCl3 which can decompose into PbCl2 and MACl. MACl can leave the perovskite film during the annealing process leading to the loss of Cl and undesirable pinholes or cracks. Here, we present the chloroformamidinium chloride (Cl FACl) as a \"stabilizer\" to stabilize Cl ions and thus restrain the removal of Cl avoiding the undesirable defects. With the introduction of Cl FACl, improvement of film quality and reduction of defects result in a longer TRPL decay time and thus more stable devices. High efficiency methylammonium lead trihalide (MAPbI3 xClx) perovskite solar cells with an efficiency up to 20.36% have been achieved with negligible hysteresis.", "author_names": [ "Yulei Wu", "Xiao-Da Li", "Sheng Fu", "Li Wan", "Junfeng Fang" ], "corpus_id": 107308650, "doc_id": "107308650", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Efficient methylammonium lead trihalide perovskite solar cells with chloroformamidinium chloride (Cl FACl) as an additive", "venue": "", "year": 2019 } ]

[ { "abstract": "A semiconductor factory goes through many phases in its life cycle including design, build, various ramps, and many levels of production. Maximizing the profitability and return on investment across this life cycle is a critical component of Intels approach to financial success. We have been applying the concepts of Goldratts Theory of Constraints across the factory life cycle and have realized improved performance in many of these phases, as well as in the integration of the phases. Within Intel Corporation, there are at least three identifiable supply lines (Figure 1) The most obvious from outside the company is the product supply line. This supply line includes planning to schedule production, materials to supply the ingredients manufacturing to produce the products, and logistics to deliver them. This is the supply line that springs into action when you place an order with Intel and find it being delivered a short time later. Another supply line for which Intel is famous is its technology supply line, which has two major branches. One is product design, delivering a stream of ever faster and more capable product designs for manufacturing to build. The other is process design, providing a sequence of ever finer and more capable processes for manufacturing to follow in building products. Together they form the supply line that responds to the insatiable market demand for faster semiconductor devices with higher func tionality. Perhaps the least obvious supply line from outside the company is the capacity supply line. This is the supply line that manages manufacturing resources. It is always trying to supply the most cost effective manufacturing capability synchronized with market demand. This supply line involves at least the selection and layout of equipment (design) construction of buildings (build) startup of production (ramp) and operation (Mfg) of Intel factories. Since managing this capacity supply line is the primary focus of this paper, we discuss how this supply line is driven, how its components work together, and what problems it must overcome. Figure 1: Intel supply lines Clearly the capacity supply line is driven by market demand. More interestingly, it is also driven by advances in process technology. As semiconductor process design moves to finer line widths, new cleaner factories with improved equipment are needed to produce cutting edge products commanding premium prices. This results in older factories being relegated to run products that are no longer at the cutting edge and which the market treats as", "author_names": [ "Karl G Kempf" ], "corpus_id": 14554910, "doc_id": "14554910", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Improving Throughput Across the Factory Life Cycle", "venue": "", "year": null }, { "abstract": "Abstract Monitoring changing customer needs and requirements, along with shorterning product development cycle times, are major concerns for manufacturing companies. Factors which influence these concerns are determined often at the front end of New Product Development (NPD) Approaches to requirements capture were investigated from telecommunications, automotive and IT industries. It was found that the automotive company used market research agencies as an ongoing input into the NPD process, while the computing company was attempting to introduce a cross disciplinary approach to both idea capture and requirements capture.", "author_names": [ "Rachel Cooper", "Andrew B Wootton", "Margaret Bruce" ], "corpus_id": 153970952, "doc_id": "153970952", "n_citations": 40, "n_key_citations": 0, "score": 1, "title": "\"Requirements capture\" theory and practice", "venue": "", "year": 1998 }, { "abstract": "This paper describes the influence of operator competence on judgement of product quality. Manual repetitive work with short work cycle was studied in a manufacturing company. One goal of the company was that all employees would be able to do most production tasks. Forty six operators participated in a field study of quality control. Based on how many tasks operators could perform, they were classified as high competence or low competence. Operators inspected 30 items, out of which 6 were of poor quality. In average 38% of the good items were rejected and 10% of the poor items were missed. Signal detection theory was used to compare the sensitivity d' and the criterion b for high and low competence operators and for departments 1 and 2. High competence operators had greater sensitivity and produced less false alarms and misses than low competence operators. The results are discussed in terms of efficiency of company policies and lack of operator feedback. In addition some tasks were perceived by operators as more prestigious and desirable to perform than others. This bias affects the desirability to learn and perform new tasks, and quality control may suffer. It is important to train and maintain competence in quality control as well as in task performance. The use of high competence operators can improve the quality in manufacturing considerably. Relevance to industry Employees with high competence who managed many production tasks performed significantly better in quality control and judgement of quality than employees who managed only few tasks.", "author_names": [ "Eva Loven", "Martin G Helander" ], "corpus_id": 109288730, "doc_id": "109288730", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Effect of operator competence on assessment of quality control in manufacturing", "venue": "", "year": 1997 }, { "abstract": "Industrial companies that carry on innovation and operation must have well organized and capable business systems and processes. Customer needs, market demands, global competition and technological changes drive the companies to be more adaptable, flexible and dynamic. By working in network structures as extended enterprises, the companies face new possibilities and new challenges. Design, manufacturing and delivery of high quality products to competitive prices to the customers are essential for industrial companies. Holistic view of the product life cycle from technology development, via product and business system development and realization, to business operation, is important for sustainable industrial companies. A company with engineering and manufacturing of products in a business context needs to have effective innovation of business system and process. Business innovation encompasses the area from business idea to business operation and includes customer demands and solutions. The main part of business innovation is development of the product platform including product and support structures. Product variants are created and realized by various configurations of products and production systems. The thesis is elucidating that business innovation can be carried out by working in a systematic and structured way and by utilizing engineering design theories and methods. The business models, based on a new theory with a new navigation tool for interactions, are describing which activities should be performed in business innovation with product platform development and product structuring. For companies in business with changes, innovations can create new markets and products. Well managed and innovative companies have good possibilities to be competitive in a tough business environment. The creation of business innovation models has been carried out according to a hermeneutic research method. The research work followed the hermeneutic circle or spiral. The thesis introduces a new dimension to the design area, namely business innovation or engineering, corresponding to business design and development. Business innovation is also a new type of innovation, combining technological, product, process, market and organizational innovations in industrial companies.", "author_names": [ "Leif Clausson" ], "corpus_id": 166328001, "doc_id": "166328001", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Business Innovation by utilizing Engineering Design Theory and Methodology", "venue": "", "year": 2006 }, { "abstract": "In today's market, obtaining a variety of products through configuration design has become increasingly common. However, with the development of the market, customers have not only satisfied the company offering a variety of products, and more demands on participating in the process of configuration design by themselves, so that they can obtain fully personalized products. Customer participation leads to the changes of design process, company's management model, etc. Based on the above problem, this thesis takes industrial robot as an example, and studies the management issues related to the customer involved in the design, in order to address the contradiction between product diversification, personalized requirements and the long design cycle and high manufacturing costs. Firstly, Auser customized configuration design pattern is presented. The theory source of user customized configuration design pattern is introduced, and then the related concepts are expounded. The corresponding business mode of user customized configuration design pattern is given, and the key technologies to realize business mode is studied. System dynamics models were established for user customized configuration design business mode and for traditional business mode of industrial robots by Anylogic simulation software. Secondly, the component based theory and method are studied, including the formal description of things, ontology representation, componentization and servitization. On this basis, the componentization description model is established for the product parts. And the model is represented as service component. Next, the formation process and extension method of service component are introduced. An example of industrial robot components modeling is analyzed, includingestablishing industrial robot domain ontology by protege, describing, instantiating and extensing components. Thirdly, the industrial robot user customized configuration design template is constructed, and users can obtain the industrial robot meeting constraints through parameters setting; The kinematics and dynamics analysis on template is taken by Simscape model, and the dynamic parameters is analyzed, and the finite element analysis on template is taken by ANSYS, including statics analysis and modal analysis. The parameters flow process in template is analyzed. Then taking industrial robot user customized configuration design using configuration template as an example, the configuration template is analyzed in application. Fourthly, the internal algorithm of user customized configuration design is researched. Platform based and user leading user customized configuration design process is constructed, and then the internal algorithm to keep the design running smoothly is studied, including the degree of freedom determination, fuzzy demand calculation, and service component configuration and the configuration program evaluation. A case analysis is also taken for the internal algorithm Finally, on the basis of the previous section, the prototype system design of the open design platform is taken. Based on system requirements analysis and system design, the main pages of the platform are designed, and the key functions are introduced", "author_names": [ "Jing Li" ], "corpus_id": 114506975, "doc_id": "114506975", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design of mechatronic products based on user customized configuration an application for industrial robots", "venue": "", "year": 2015 }, { "abstract": "Lean production is a way to promote production and manage the level of manufacturing as well as to enhance competitiveness in a workshop. Welding is one of the key links of the four important technology processes in auto manufacturing. Based on the theory of lean thinking, this paper took the CS (Changhe) Automobile Company as a specific case and analyzed the current situation of its welding workshop with the SWOT matrix. Conclusions are drawn that enhancement of the logistics system of the welding workshop is necessary. Led by the thought of JIT (just in time) and the balancing of lean production, the basic idea of improving the logistics system is discussed here, and the specific programs for improving the workshop logistics system are put forth. By comparing the improved data, the conclusion shows that the logistics cycle times are cut, site areas are saved, product quality is controlled effectively, labor intensity is significantly reduced, and the production balance in the welding workshop is significantly improved. Thus, the improvement of a welding workshop logistics system based on lean thinking contributes to improving vehicle quality, reducing manufacturing costs, and promoting production efficiency.", "author_names": [ "Haitao Su", "Xiaoyan Jiang", "Yan Xue", "Libao Li" ], "corpus_id": 109015272, "doc_id": "109015272", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Improvement of a Welding Workshop Logistics System Based on Lean Thinking", "venue": "", "year": 2010 }, { "abstract": "In recent years a growing number of firms have reported dramatic results from an operation's improvement technique called Constraint Management (CM) For example, Ford Motor Company's Electronics division attributes reductions in manufacturing cycle time as high as 89 per cent, 76 per cent fewer product returns, reductions in inventory of 49 per cent and 43 per cent lower freight costs to its implementation of CM. Others such as GM, Grand Rapids Spring and Wire, Valmont/ALS, and Kent Moore Cabinets report similar results. The purpose of this paper is to provide the reader with a basic understanding of Constraint Management, which has also been referred to as synchronized manufacturing; the Drum, Buffer, Rope technique; OPT (Optimized Production Technology) the Theory of Constraints, and to explore its potential impact on logistics managers.", "author_names": [ "George C Jackson", "James T Low" ], "corpus_id": 167383751, "doc_id": "167383751", "n_citations": 9, "n_key_citations": 2, "score": 0, "title": "Constraint Management: A Description and Assessment", "venue": "", "year": 1993 }, { "abstract": "Green supply chain management (GSCM) is a modern management model which designs supply chain in ecological method from the view point of product life cycle. In order to optimize the economic performance, environmental and social benefit with high resource efficiency, green supply chain needs close cooperation between sections inside the company and the enterprises, thus integrating environmental management into the supply chain management harmoniously. The theory of green supply chain management is still not systematic but progressive.GSCM can be divided into four research fields: green manufacturing, green purchasing, green logistics, green marketing. Perfecting the environmental law, strengthening the supervising ability of government, cultivating the environmental habit of consumers, advancing the information and environmental protection technology of enterprises will be needed in carrying out GSCM in our country.", "author_names": [ "Shen Cheng-lin" ], "corpus_id": 167985820, "doc_id": "167985820", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Summarization of Green Supply Chain Management", "venue": "", "year": 2004 }, { "abstract": "Abstract This paper examines how organizations connect internal and external processes to enable an agile response to continuous change. Drawing on life cycle theory, a hypothetical model is developed regarding the independent and combinative effects of internal and external process connectivity on supply chain agility and the moderating effect of product and supply complexity. The model is tested using hierarchical regression analysis based on survey data from 143 managers at German manufacturing firms. Our findings suggest that internal and external process connectivity have a positive effect on supply chain agility independently and collectively, with complexity having a moderating effect in particular instances. The findings build on prior research regarding the process related enablers of supply chain agility; research that has yet to clearly differentiate between internal and external processes or uses the terms interchangeably. The theoretical contribution of the paper rests on its extension of life cycle theory to the supply chain.", "author_names": [ "Samuel Roscoe", "Dominik Eckstein", "Constantin Blome", "Matthias Goellner" ], "corpus_id": 155740668, "doc_id": "155740668", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Determining how internal and external process connectivity affect supply chain agility: a life cycle theory perspective", "venue": "Production Planning Control", "year": 2019 }, { "abstract": "Abstract Implementing sustainability principles of the circular economy and associated transitions tend to transcend the boundaries of individual businesses. This calls for a shift in traditional sustainability thinking by transitioning from business oriented sub optimisation to collaborative value chain optimisation. This paper proposes a framework to support companies in this transition by visualising the different relations in a morphological matrix to encourage the selection of the most appropriate principles for the specific industry context. The framework is evaluated in an industrial case with multiple stakeholders resulting in a feasible closed material loop.", "author_names": [ "Willem Haanstra", "Marten E Toxopeus", "M R van Gerrevink" ], "corpus_id": 113553885, "doc_id": "113553885", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Product Life Cycle Planning for Sustainable Manufacturing: Translating Theory into Business Opportunities", "venue": "", "year": 2017 } ]

[ { "abstract": "Abstract The present work was aimed to investigate the electric and dielectric behavior of synthesized graphene oxide as a function of both temperature ranging from the ambient to 873K and frequency varying between 10 Hz and 10 MHz. Graphene oxide nanosheets were prepared by the modified Hummer's Method. The structural and morphological properties were characterized by X Ray diffraction, FTIR and Raman spectroscopies. The ac conductivity, dc conductivity, dielectric constant and loss factors were obtained. Constant phase elements allowed to obtain an equivalent electrical circuit by fitting the theoretical approximations to the experimental results. The synthesized graphene oxide (GO) exhibited high values of dielectric constant e'(o) and low losses. The obtained GO could be a good candidate for semiconductor compound and may be used in colossal memories.", "author_names": [ "K Riahi", "Nasr Sdiri", "Dorra Jellouli Ennigrou", "Karima Horchani-Naifer" ], "corpus_id": 218994047, "doc_id": "218994047", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Investigations on electrical conductivity and dielectric properties of graphene oxide nanosheets synthetized from modified Hummer's method", "venue": "", "year": 2020 }, { "abstract": "The aim of this work is to invent a novel technology for manufacture not only graphene oxide, but also conductive graphene oxide. This is the novelty in this technology, which is not available in any other method for preparing graphene oxide. This study describes a unique way for preparation of conductive nano particles of graphene oxide, GO. The advantages of this technology is very simple, low cost, short time of preparation and can be manufacture a large amount of conductive GO by firing polyvinyl alcohol PVA on SiO2/pSi to preparation this assembly GO/SiO2/pSi as a Schottky barrier diode or Metal Oxide Semiconductor, MOS. Besides the pioneering in this article GO is deemed insulator, however with rising temperature through firing PVA, its conductivity remarkably enhances and the produced GO can be used as a conductor. The as prepared sample has been characterized using different techniques (e.g. Scanning Electron Microscopy (SEM) Raman Spectroscopy, X Ray diffraction (XRD) and Impedance Spectroscopy. Temperature, voltage and frequency dependences of M' M' 1/C2, Rs, sac and tand of GO/SiO2//p Si diodes were achieved in the varied ranges of voltage and frequency. I V characteristic of GO/SiO2/pSi Schottky diode is taken at different temperatures. The elementary factors of the diode such as barrier height (Phb) series resistance (Rs) and ideality factor (n) of GO/SiO2/pSi are also considered. The nyquist plot of M'(M' at different voltages and temperatures were examined.", "author_names": [ "A Ashery", "Mohammed A Moussa", "Gamal Turky" ], "corpus_id": 231921553, "doc_id": "231921553", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Enhancement of Electrical and Dielectric Properties of Graphene Oxide nanoparticle Based Devices", "venue": "Silicon", "year": 2021 }, { "abstract": "Synthesis of a new nanocomposite composed of poly (vinyl chloride co vinyl acetate co 2 hydroxypropyl acrylate) (PVVH) copolymer and graphene oxide (GO) was successfully achieved using solution casting technique. Dielectric properties of the nanocomposite were investigated in the frequency range (10 Hz to 10 MHz) over the temperature range (298 373 K) Many variables such as: dielectric constant, dielectric loss, loss tangent, electric moduli and AC conductivity were studied with changing frequency and temperature, showing improvement in the nanocomposite properties with both of them. The non Debye behaviour of the samples was confirmed from the electric modulus analysis. AC conductivity (sac) was found to follow Jonscher's universal power law. The enhancement in (sac) with frequency and temperature has implied the presence of free charge carriers that pass by hopping through defect sites over the potential barriers separating them in the PVVH/GO matrix. The correlated barrier hopping (CBH) model was found to be the best choice for describing AC conduction mechanism in the current nanocomposite over the above temperature range. Scaling of (sac) carried out for the prepared samples has exhibited that charge carriers within the current matrix follow a common conduction mechanism. A comparison between maximum barrier height and activation energy has been carried out to demonstrate the charge carriers transport mechanism. The PVVH based nanocomposite with the highest concentration of GO (4 wt% has achieved the highest enhancement in (sac) and mechanical properties, suggesting the feasibility of using it in designing electrochemical and energy storage devices.", "author_names": [ "A Y Yassin", "A Raouf Mohamed", "A M Abdelghany", "Elmetwaly M Abdelrazek" ], "corpus_id": 139418855, "doc_id": "139418855", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Enhancement of dielectric properties and AC electrical conductivity of nanocomposite using poly (vinyl chloride co vinyl acetate co 2 hydroxypropyl acrylate) filled with graphene oxide", "venue": "Journal of Materials Science: Materials in Electronics", "year": 2018 }, { "abstract": "Abstract Graphene oxide (GO) has been synthesized by modified Hummers' method and characterized by Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, X ray diffraction technique and Raman spectroscopy. GO characterized using Fourier transform infrared spectra shows that the graphite powder is strongly oxidized by resilient oxidants and the oxygen atoms are present in form of functional groups such as COOH, O H, C O C, and C O, bonds. GO pellets were prepared to study its dielectric properties as a function of frequency. Dielectric permittivity and electrical conductivity of GO strongly depends upon the extent of temperature.", "author_names": [ "Pushpendra Kumar", "Santhosh Penta", "Shyama Prasad Mahapatra" ], "corpus_id": 213540836, "doc_id": "213540836", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Dielectric Properties of Graphene Oxide Synthesized by Modified Hummers' Method from Graphite Powder", "venue": "Integrated Ferroelectrics", "year": 2019 }, { "abstract": "Abstract Polyaniline nanofibers (PANI NFs) was prepared by Interfacial and rapid mixing polymerization Fourier transform infrared (FTIR) X ray diffraction (XRD) and Scanning Electron Microscope (SEM) were used to examine of pure nanofibers. The structural, optical, thermal, and conductivity properties of pure blend and PNCs were studied by using FTIR, XRD, SEM, UV Vis. DTA TGA, and Ac conductivity measurement techniques and have been prepared using the casting method. The analysis of FT IR reflects forming hydrogen bond between the PANI and PMMA. Also it's confirmed the presence interaction between GO NPs with the functional groups of PMMA/PANI matrix. The XRD data revealed the increase of amorphous domains of nanocomposites comparing to that of the pure polymer blend. The SEM indicates the uniform distribution of GO NPs on the surface of the prepared samples. From UV. Vis showed the values of optical energy gap (direct and indirect) for pure blend and nanocomposites decreases with increasing content of GO NPs. Based on DTA and TGA data, the thermal stability of all the investigated samples were improved and the activation energies were calculated. Electrical conductivity analysis indicates that the 0.9 wt sample have a larger conductivity compared to that of prepared samples. The increase in conductivity was mainly due to the increase in mobility of charge carrier according to free volume model.", "author_names": [ "M M Abutalib" ], "corpus_id": 104747028, "doc_id": "104747028", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Insights into the structural, optical, thermal, dielectric, and electrical properties of PMMA/PANI loaded with graphene oxide nanoparticles", "venue": "", "year": 2019 }, { "abstract": "Abstract Graphene oxide (GO) films can be used in structural dielectric capacitors (SDCs) as both primary structures and energy storage devices for large transportation equipment like aircraft. To meet the high requirements for aviation application, in this paper the mechanical and dielectric properties of GO films were optimized by concisely tailoring their carbon to oxygen (C/O) ratio. Our results show that both the mechanical and electrical conductivity of GO films increase with increasing the C/O ratio. This work also demonstrates that both mechanical and dielectric properties of GO films can be enhanced simultaneously through a mild reduction whilst retaining the electrical insulating nature of GO for SDC applications. The insights provided in this work would be beneficial not only for SDC applications but also for fundamental studies and developments of GO related materials.", "author_names": [ "Kit-ying Chan", "Ardeshir Baktash", "Baris Demir", "Edwin L H Mayes", "Dan Yang", "Duy Quang Pham", "Keng-Te Lin", "Adrian Mouritz", "Andrew Siao Ming Ang", "Bronwyn L Fox", "Bo Zhu", "Han Lin", "Baohua Jia", "Kin-tak Alan Lau" ], "corpus_id": 225122564, "doc_id": "225122564", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Tailoring mechanical and electrical properties of graphene oxide film for structural dielectric capacitors", "venue": "", "year": 2021 }, { "abstract": "Graphene metal nanocomposites are the best candidates for the greater sensitivity for various applications. We have prepared Graphene Tin Oxide (G/SnO2) nanocomposite by using facile eco friendly Anton Paar microwave synthesis reactor method. X ray diffraction patterns revealed the formation of G/SnO2 nanocomposite. The scanning electron microscopy and transmission electron microscopy images show a uniform distribution of nano needles on the graphene surface and the average particle size was found to be in the range of 3 5 nm. The G/SnO2 composite shows an enhanced optical property, i.e. tunability in the band of pristine SnO2 nanoparticles while in contacted with graphene. The dielectric properties of the G/SnO2 nanocomposite were measured in the frequency ranges of 75Hz to 4MHz and real value of dielectric constant is found to be 1200, which is quite larger than that of pristine SnO2 nanoparticle, i.e. 12. Further, AC conductivity analysis revealed that the G/SnO2 is two orders conductive than the pristine SnO2. This work may offer an effective and economically viable for the preparation of graphene/metal oxide nanocomposites for various applications.", "author_names": [ "Moheeta Khan", "Azra Parveen" ], "corpus_id": 212719817, "doc_id": "212719817", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Microwave Assisted Synthesis of Graphene/SnO2 Nanocomposite and its Structural, Dielectric and Electrical Properties", "venue": "", "year": 2020 }, { "abstract": "Graphene oxide (GO) nanofiller were incorporated in PVP/PVA blend films for the preparation of nanocomposite polymer films by the solution cast method. The films were characterized using SEM, D.C and A.C and dielectric properties studies at room temperature. SEM structure shows that the GO exfoliated and uniformly dispersed in PVP/PVA matrix. DC conductivity studies were under taken at (303 336) K, and the conductivity was found to be 3.3x10 O.cm for the polymer film prepared at 336K. The A.C electrical conductivity increase with the increase of frequency. The dielectric properties were measured the frequency range 100Hz 5MHz at room temperature show that the dielectric constant (real and imaginary) decrease with the increase of Graphene oxide nanoparticles concentrations.", "author_names": [ "Nadia Abbas Ali" ], "corpus_id": 211733130, "doc_id": "211733130", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Graphene oxide on the electrical properties D.C and A.C and dielectric constant of PVP/PVA Nanocomposites", "venue": "", "year": 2018 }, { "abstract": "Lanthanum Ferrite based nanocomposites were prepared with various Graphene oxide contents by the hydrothermal method. The crystalline structure, morphological properties, electrical and optical properties of samples were investigated. X ray diffraction results indicate that all the nano electroceramics are polycrystalline with an Orthorhombic structure. Results from scanning and transmission electron microscopes indicate that the Bismuth ferrite/Graphene oxide powders have nanostructure. The optical band gaps of the nano electroceramics were calculated for the various amount of Graphene oxide. The electrical properties of samples were investigated with the temperature depend on conductivity measurements. The measurement shows that the electrical conductivity changes with increasing temperature and graphene oxide dopants of all samples. Activation energy (EA) values of the nanocomposites decrease with increasing graphene oxide content. The dielectric properties of Lanthanum Ferrite/Graphene Oxide nanocomposites (real and imaginer) with respect to frequency variation (1 KHz 5 MHz) were measured at room temperature. The relative permittivity (e' dielectric loss (e' and alternating current conductivity (sac) values of the samples were estimated. It is show that (e' (e' and (sac) increase with increasing frequency. The polarization electric field hysteresis loop of all Lanthanum Ferrite/Graphene Oxide nano electroceramics was measured at the room temperature. The loop shows proper saturation with enhanced saturation polarization (Ps) remnant polarization (Pr) and coercive electric field (Ec) The obtained findings suggest that the physical and electrical properties of Lanthanum Ferrite/Graphene Oxide nano electroceramics can be changed by Graphene Oxide doping. These materials can be used for a variety of technological applications in the field of dielectric and ferroelectric.", "author_names": [ "C Aydin", "H Aydin", "Mustafa Taskin", "Fahrettin Yakuphanoglu" ], "corpus_id": 54488261, "doc_id": "54488261", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "A Novel Study: The Effect of Graphene Oxide on the Morphology, Crystal Structure, Optical and Electrical Properties of Lanthanum Ferrite Based Nano Electroceramics Synthesized by Hydrothermal Method.", "venue": "Journal of nanoscience and nanotechnology", "year": 2019 }, { "abstract": "In this study, Yttrium Ferrite based nano electroceramics were prepared by the doping at various ratios of graphene oxide by the hydrothermal method. The obtained doped and undoped samples were characterized by XRD, SEM, FTIR, DTA, UV VIS NIR spectroscopy, temperature dependent electrical resistance changes and dielectric measurements. From the XRD results, it is observed that the obtained samples are polycrystalline with an Orthorhombic structure. The crystal parameters are changed with the doping of graphene oxide. FTIR spectra indicate that the graphene oxide changes the peak intensities. This confirms the incorporation of the graphene oxide into the ceramic structure. The doping of the graphene oxide changes the optical band gaps of the samples. The dielectric constants of the samples are changed with the graphene oxide. The DC electrical conductivity measurements confirm the semiconducting behavior of the samples. The obtained results indicate that the electronic and nanostructure of the synthesized electroceramics can be controlled by the doping of graphene oxide for electronic and energy applications.", "author_names": [ "H Aydin" ], "corpus_id": 202975913, "doc_id": "202975913", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "THE EFFECT OF GRAPHENE OXIDE ON THE STRUCTURAL AND ELECTRICAL PROPERTIES OF YTTRIUM FERRITE BASED NANOPOWDERS", "venue": "European Journal of Technic", "year": 2019 } ]

[ { "abstract": "Fluorescent carbon nanoparticles or carbon quantum dots (CQDs) are a new class of carbon nanomaterials that have emerged recently and have garnered much interest as potential competitors to conventional semiconductor quantum dots. In addition to their comparable optical properties, CQDs have the desired advantages of low toxicity, environmental friendliness low cost and simple synthetic routes. Moreover, surface passivation and functionalization of CQDs allow for the control of their physicochemical properties. Since their discovery, CQDs have found many applications in the fields of chemical sensing, biosensing, bioimaging, nanomedicine, photocatalysis and electrocatalysis. This article reviews the progress in the research and development of CQDs with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.", "author_names": [ "Shi Ying Lim", "Wei Shen", "Zhiqiang Gao" ], "corpus_id": 19393519, "doc_id": "19393519", "n_citations": 2473, "n_key_citations": 21, "score": 1, "title": "Carbon quantum dots and their applications.", "venue": "Chemical Society reviews", "year": 2015 }, { "abstract": "Strategies for selectively imaging and delivering drugs to tumours typically leverage differentially upregulated surface molecules on cancer cells. Here, we show that intravenously injected carbon quantum dots, functionalized with multiple paired a carboxyl and amino groups that bind to the large neutral amino acid transporter 1 (which is expressed in most tumours) selectively accumulate in human tumour xenografts in mice and in an orthotopic mouse model of human glioma. The functionalized quantum dots, which structurally mimic large amino acids and can be loaded with aromatic drugs through p p stacking interactions, enabled in the absence of detectable toxicity near infrared fluorescence and photoacoustic imaging of the tumours and a reduction in tumour burden after the targeted delivery of chemotherapeutics to the tumours. The versatility of functionalization and high tumour selectivity of the quantum dots make them broadly suitable for tumour specific imaging and drug delivery. Intravenously injected functionalized carbon quantum dots that bind to the large neutral amino acid transporter 1 and that structurally mimic large amino acids selectively accumulate in human tumours in mice, facilitating targeted theranostics.", "author_names": [ "Shuhua Li", "Wen Su", "Hao Wu", "Ting Yuan", "Chang Yuan", "Jun Liu", "Gang Deng", "Xingchun Gao", "Zeming Chen", "Youmei Bao", "Fanglong Yuan", "Shixin Zhou", "Hongwei Tan", "Yunchao Li", "Xiaohong Li", "Louzhen Fan", "Jia Zhu", "Ann Tai Chen", "Fuyao Liu", "Yu Zhou", "Miao Li", "Xingchen Zhai", "Jiangbing Zhou" ], "corpus_id": 214704171, "doc_id": "214704171", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids", "venue": "Nature Biomedical Engineering", "year": 2020 }, { "abstract": "Carbon quantum dots (CQDs) as an emerging class of quantum dots (QDs) with advantages such as good photoluminescence (PL) properties, easy synthesis routes, economical synthesis, cheap starting materials, water solubility, low levels of toxicity, chemical stability, and easy functionalization have received great attention during recent years. CQDs have been used in versatile sensor applications. CQD sensors could be ultimately sensitive, and the limit of detection (LOD) for these sensors can reach the nanomolar, picomolar or even femtomolar ranges. CQD based sensors and biosensors work with different mechanisms including fluorescence quenching, static quenching, dynamic quenching, energy transfer, inner filter effect (IFE) photo induced electron transfer (PET) and fluorescence resonance energy transfer (FRET) CQD based sensors and biosensors have been applied for the detection of different species such as metal ions, acids, proteins, biothiols, polypeptides, DNA and miRNA, water pollutants, hematin, drugs, vitamins, and other chemicals. It seems that CQD based sensors and biosensors are promising candidates for high performance and yet accurate sensors in different areas. In this review, CQDs are introduced, and the synthesis methods and optical properties of CQDs are discussed. Different types of CQD based sensors and biosensors and their working mechanisms are clarified.", "author_names": [ "Mohammad Jafar Molaei" ], "corpus_id": 213782522, "doc_id": "213782522", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Principles, mechanisms, and application of carbon quantum dots in sensors: a review", "venue": "", "year": 2020 }, { "abstract": "Efficient full color fluorescent carbon quantum dots are synthesized by acid reagent engineering for white light emitting devices. Quantum dots have innate advantages as the key component of optoelectronic devices. For white light emitting diodes (WLEDs) the modulation of the spectrum and color of the device often involves various quantum dots of different emission wavelengths. Here, we fabricate a series of carbon quantum dots (CQDs) through a scalable acid reagent engineering strategy. The growing electron withdrawing groups on the surface of CQDs that originated from acid reagents boost their photoluminescence wavelength red shift and raise their particle sizes, elucidating the quantum size effect. These CQDs emit bright and remarkably stable full color fluorescence ranging from blue to red light and even white light. Full color emissive polymer films and all types of high color rendering index WLEDs are synthesized by mixing multiple kinds of CQDs in appropriate ratios. The universal electron donating/withdrawing group engineering approach for synthesizing tunable emissive CQDs will facilitate the progress of carbon based luminescent materials for manufacturing forward looking films and devices.", "author_names": [ "Liang Wang", "Weitao Li", "Luqiao Yin", "Yijiang Liu", "Huazhang Guo", "Jiawei Lai", "Yu Han", "Gao Li", "Ming Li", "Jianhua Zhang", "Robert Vajtai", "Pulickel M Ajayan", "Minghong Wu" ], "corpus_id": 222110938, "doc_id": "222110938", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Full color fluorescent carbon quantum dots", "venue": "Science Advances", "year": 2020 }, { "abstract": "Abstract Currently, the disposal of municipal wastes (paper, plastic, and coffee residue) is a problem due to increasing the amount of municipal wastes, global environmental problems, and high disposal cost. Here, we report the synthesis of carbon quantum dots from waste paper by different solvents by a conventional hydro /solvothermal method for solving the environmental and disposal problems. The carbon quantum dots synthesized with waste papers have several advantages such as low toxicity, low cost, and eco friendly. The prepared carbon quantum dots have main emission peak from 440 to 540 nm under 340 480 nm excitation. The prepared carbon quantum dots can be applied to easily prepare anti counterfeiting ink and fluorescent flexible film because of their unique optical property and excellent chemical and photostability.", "author_names": [ "Sung Jun Park", "Jin Young Park", "Jong Won Chung", "Hyun Kyoung Yang", "Byung Kee Moon", "Soung Soo Yi" ], "corpus_id": 208735373, "doc_id": "208735373", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Color tunable carbon quantum dots from wasted paper by different solvents for anti counterfeiting and fluorescent flexible film", "venue": "", "year": 2020 }, { "abstract": "Large doses of anticancer drugs entering cancer cell nuclei are found to be effective at killing cancer cells and increasing chemotherapeutic effectiveness. Here we report red emissive carbon quantum dots, which can enter into the nuclei of not only cancer cells but also cancer stem cells. After doxorubicin was loaded at the concentration of 30 mg/mL on the surfaces of carbon quantum dots, the average cell viability of HeLa cells was decreased to only 21% while it was decreased to 50% for free doxorubicin. The doxorubicin loaded carbon quantum dots also exhibited a good therapeutic effect by eliminating cancer stem cells. This work provides a potential strategy for developing carbon quantum dot based anticancer drug carriers for effective eradication of cancers.", "author_names": [ "Wen Su", "Ruihua Guo", "Fanglong Yuan", "Yunchao Li", "Xiaohong Li", "Yang Zhang", "Shixin Zhou", "Louzhen Fan" ], "corpus_id": 211035565, "doc_id": "211035565", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Red Emissive Carbon Quantum Dots for Nuclear Drug Delivery in Cancer Stem Cells.", "venue": "The journal of physical chemistry letters", "year": 2020 }, { "abstract": "Carbon and graphene quantum dots are prepared using top down and bottom up methods. Sustainable synthesis of quantum dots has several advantages such as the use of low cost and non toxic raw materials, simple operations, expeditious reactions, renewable resources and straightforward post processing steps. These nanomaterials are promising for clinical and biomedical sciences, especially in bioimaging, diagnosis, bioanalytical assays and biosensors. Here we review green methods for the fabrication of quantum dots, and biomedical and biotechnological applications.", "author_names": [ "Siavash Iravani", "Rajender S Varma" ], "corpus_id": 212643318, "doc_id": "212643318", "n_citations": 71, "n_key_citations": 1, "score": 0, "title": "Green synthesis, biomedical and biotechnological applications of carbon and graphene quantum dots. A review", "venue": "Environmental Chemistry Letters", "year": 2020 }, { "abstract": "Nitrogen doped carbon quantum dots (N CQDs) were successfully synthesized using rice residue and glycine as carbon and nitrogen sources by one step hydrothermal method. High quantum yield (23.48% originated from the effective combination of nitrogen with various functional groups (CO, NH, CN, COOH and COC) The N CQDs showed a fluorescence with the wavelength varied from 420 to 500 nm and the maximum emission wavelength being at 440 nm. N CQDs have been importantly applied as probe to detect Fe3+ and tetracycline (TCs) antibiotics with remarkable performance. Using the linear relationship between fluorescence intensity and Fe3+ concentration, the N CQDs could be employed as a simple, efficient sensor for ultrasensitive Fe3+ detection ranging from 3.32 to 32.26 uM, with a limit of detection (LOD) of 0.7462 uM. The N CQDs showed the applicability to detect TCs. The detection limits of tetracycline, terramycin and chlortetracycline were 0.2367, 0.3739 and 0.2791 uM, respectively. The results of TC by fluorescence method in real water samples were in good agreement with standard Ultraviolet visible (UV vis) method. The N CQDs have various potential applications including sensitive and selective detection of Fe3+ and TCs, and cellular imaging with low cytotoxicity, good biocompatibility and high permeability.", "author_names": [ "Houjuan Qi", "Min Teng", "Miao Liu", "Shouxin Liu", "Jian Li", "Haipeng Yu", "Chunbo Teng", "Zhanhua Huang", "Hu Liu", "Qian Shao", "Ahmad Umar", "Tao Ding", "Qiang Gao", "Zhanhu Guo" ], "corpus_id": 58602387, "doc_id": "58602387", "n_citations": 187, "n_key_citations": 1, "score": 0, "title": "Biomass derived nitrogen doped carbon quantum dots: highly selective fluorescent probe for detecting Fe3+ ions and tetracyclines.", "venue": "Journal of colloid and interface science", "year": 2019 }, { "abstract": "Therapeutic options for the highly pathogenic human coronavirus (HCoV) infections are urgently needed. Anticoronavirus therapy is however challenging, as coronaviruses are biologically diverse and rapidly mutating. In this work, the antiviral activity of seven different carbon quantum dots (CQDs) for the treatment of human coronavirus HCoV 229E infections was investigated. The first generation of antiviral CQDs was derived from hydrothermal carbonization of ethylenediamine/citric acid as carbon precursors and postmodified with boronic acid ligands. These nanostructures showed a concentration dependent virus inactivation with an estimated EC50 of 52 8 mg mL 1. CQDs derived from 4 aminophenylboronic acid without any further modification resulted in the second generation of anti HCoV nanomaterials with an EC50 lowered to 5.2 0.7 mg mL 1. The underlying mechanism of action of these CQDs was revealed to be inhibition of HCoV 229E entry that could be due to interaction of the functional groups of the CQDs with HCoV 229E entry receptors; surprisingly, an equally large inhibition activity was observed at the viral replication step.", "author_names": [ "Aleksandra Loczechin", "Karin Seron", "Alexandre Barras", "Emerson Giovanelli", "Sandrine Belouzard", "Yen-Ting Chen", "Nils Metzler-Nolte", "Rabah Boukherroub", "Jean Dubuisson", "Sabine Szunerits" ], "corpus_id": 204814784, "doc_id": "204814784", "n_citations": 104, "n_key_citations": 2, "score": 0, "title": "Functional Carbon Quantum Dots as Medical Countermeasures to Human Coronavirus", "venue": "ACS applied materials interfaces", "year": 2019 }, { "abstract": "Abstract Microbial contamination and antibiotic pollutions diffusely exist in wastewater system, and contaminated water poses a threat to public health. Therefore, there is a need to effectively remove biohazard and antibiotic contamination from wastewater systems. In this paper, sulfur doped carbon quantum dots (S CQDs)/hollow tubular g C3N4 photocatalyst (HTCN C) prepared via ultrasonic assisted synthesis strategy, was regarded as an efficient catalyst for the degradation of antibiotic (tetracycline) and destruction of a typical Gram negative bacterium (Escherichia coli) in imitated wastewater system. The unique structures of hollow tubular g C3N4 and loading of modified carbon quantum dots enhanced electron transfer and charge separation, leading to a significant improvement in photocatalytic efficiency. Benefiting from these merits, the optimized catalysts (HTCN C(2) exhibited superior performance with a reaction rate of 0.0293 min 1 for tetracycline (TC) degradation and 99.99% destruction of Escherichia coli under visible light irradiation. Moreover, the characterization of UV Vis diffuse reflectance spectra, photoluminescence technique, transient photocurrent responses and electrochemical impedance spectroscopy also verified the good optical and electrochemical properties of resultant samples. Our current work indicates that HTCN C has great potential in degradation of antibiotic and destruction of bacterium for practical wastewater treatment.", "author_names": [ "Wenjun Wang", "Zhuotong Zeng", "Guangming Zeng", "Chen Zhang", "Rong Xiao", "Chengyun Zhou", "Weiping Xiong", "Yongxiang Yang", "Lei Lei", "Yang Liu", "Danlian Huang", "Min Cheng", "Ya-Ya Yang", "Yukui Fu", "Hanzhuo Luo", "Yin Zhou" ], "corpus_id": 198367887, "doc_id": "198367887", "n_citations": 169, "n_key_citations": 0, "score": 0, "title": "Sulfur doped carbon quantum dots loaded hollow tubular g C3N4 as novel photocatalyst for destruction of Escherichia coli and tetracycline degradation under visible light", "venue": "", "year": 2019 } ]

[ { "abstract": "Abstract The rapid increase in the efficiency of perovskite solar cells (PSCs) in last few decades have made them very attractive to the photovoltaic (PV) community. However, the serious challenge is related to the stability under various conditions and toxicity issues. A huge number of articles have been published in PSCs in the recent years focusing these issues by employing different strategies in the synthesis of electron transport layer (ETL) active perovskite layer, hole transport layer (HTL) and back contact counter electrodes. This article tends to focus on the role and classification of different materials used as HTL in influencing long term stability, in improving the photovoltaic parameters and thereby enhancing the device efficiency. Hole Transport Materials (HTMs) are categorized by dividing into three primary types, namely; organic, inorganic and carbonaceous HTMs. To analyze the role of HTM in detail, we further divide these primary type of HTMs into different subgroups. The organic based HTMs are subdivided into three categories, namely; long polymer HTMs, small molecule HTMs and cross linked polymers and the inorganic HTMs have been classified into nickel (Ni) derivatives and copper (Cu) derivatives based HTMs, p type semiconductor based HTMs and transition metal based HTMs. We further analyze the dual role of carbonaceous materials as HTM and counter electrode in the perovskite devices. In addition, in this review, an overview of the preparation methods, and the influence of the thickness of the HTM layers on the performance and stability of the perovskite devices are also provided. We have carried out a detailed comparison about the various classification of HTMs based on their cost effectiveness and considering their role on effective device performance. This review further discusses the critical challenges involved in the synthesis and device engineering of HTMs. This will provide the reader a better insight into the state of the art of perovskite solar devices.", "author_names": [ "Selvakumar Pitchaiya", "Muthukumarasamy Natarajan", "Agilan Santhanam", "Vijayshankar Asokan", "Akila Yuvapragasam", "Venkatraman Madurai Ramakrishnan", "Subramaniam E Palanisamy", "Senthilarasu Sundaram", "Dhayalan Velauthapillai" ], "corpus_id": 103678112, "doc_id": "103678112", "n_citations": 61, "n_key_citations": 1, "score": 1, "title": "A review on the classification of organic/inorganic/carbonaceous hole transporting materials for perovskite solar cell application", "venue": "", "year": 2020 }, { "abstract": "This paper presents the Efficiency Tables of materials considered as emerging inorganic absorbers for photovoltaic solar cell technologies. The materials collected in these Tables are selected based on their progress in recent years, and their demonstrated potential as future photovoltaic absorbers. The first part of the paper consists of the guidelines for the inclusion of the different technologies in this paper, the verification means used by the authors, and recommendation for measurement best practices. The second part details the highest world class certified solar cell efficiencies, and the highest non certified cases (some independently confirmed) The third part highlights the new entries including the record efficiencies, as well as new materials included in this version of the Tables. The final part is dedicated to review a specific aspect of materials research that the authors consider of high relevance for the scientific community. In this version of the Efficiency Tables, we are including an overview of the latest progress in theoretical methods for modelling of new photovoltaic absorber materials expected to be synthesized and confirmed in the near future. We hope that this Emerging Inorganic Solar Cell Efficiency Tables (Version 1) paper, as well as its future versions, will advance the field of emerging photovoltaic solar cells by summarizing the progress to date and outlining the future promising research directions.", "author_names": [ "Lydia Helena Wong", "Andriy Zakutayev", "Jonathan D Major", "Xiaojing Hao", "Aron Walsh", "Teodor K Todorov", "Edgardo Saucedo" ], "corpus_id": 181586080, "doc_id": "181586080", "n_citations": 30, "n_key_citations": 0, "score": 1, "title": "Emerging inorganic solar cell efficiency tables (Version 1)", "venue": "Journal of Physics: Energy", "year": 2019 }, { "abstract": "Abstract Solar cells are emerging as serious contenders to rival leading energy sources to generate electricity for environment friendly renewable and sustainable energy technologies. Earth is receiving an incredible amount of solar energy which can be converted into electricity by means of high performance solar cells for meeting the future global energy needs. This article reviews the rapid progress in the developments of inorganic and organic solar cells (SCs) such as silicon SCs, perovskite SCs, III V SCs, quantum dot SCs, dye sensitized SCs, flexible SCs, thin film SCs and tandem SCs. This article highlights the factors influencing the photovoltaic (PV) performance of SCs such as solar cell architectures, photovoltaic materials, photo electrode materials, operational and thermal stability challenges, recombination losses, thermal and chemical treatments, trap defects, hole transport materials and optical irradiation. This paper also point out the reliability issues and challenges in the commercialization of SCs. Solar cells are emerging as a promising solution for power generating windows, power saving display systems, self powered flexible and wearable electronic devices, building integrated photovoltaics, charging of e vehicles, space craft and satellite applications and solar lighting.", "author_names": [ "J Ajayan", "D Nirmal", "P MohanKumar", "M S Saravanan", "M Jagadesh", "L Arivazhagan" ], "corpus_id": 218956657, "doc_id": "218956657", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "A review of photovoltaic performance of organic/inorganic solar cells for future renewable and sustainable energy technologies", "venue": "", "year": 2020 }, { "abstract": "Abstract Photovoltaic research has recently attracted great attention. Photovoltaic energy with the solution of methylimine incorporating with lead halide perovskite absorbent has reached the efficiency of almost 21% in configurations of solid state devices, which has replaced traditional dye sensitized solar cells and evaporated organic solar cells as well as several thin film photovoltaic films. Due to development in photovoltaic devices and its promising results, interest in this research has been increased. Consequently, it is essential to explain the operational mechanism of solar cells based on perovskite for further development. In this article, we present the structure and the method preparation of methylamine lead halide of organic inorganic hybrid perovskite and review its current research on the application of solar cells. Meanwhile, the comparative analysis has been made between different points of view and key issues such as the choice of materials, the architecture of the device etc.", "author_names": [ "Ubaid Khan", "Yu Zhi-nong", "Abbas Khan", "Almas Zulfiqar", "Qudrat Ullah Khan" ], "corpus_id": 201224925, "doc_id": "201224925", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Organic inorganic hybrid perovskites based on methylamine lead halide solar cell", "venue": "Solar Energy", "year": 2019 }, { "abstract": "Abstract Perovskite (CH3NH3PbI3) semiconductor materials are promising high performance light energy absorber for solar cell application. However, the power conversion efficiency of perovskite solar cell is severely affected by the surface quality of the deposited thin film. Spin coating is a low cost and widely used deposition technique for perovskite solar cell. Notably, film deposited by spin coating evolves surface hydroxide and defeats from uncontrolled precipitation and inter diffusion reaction. Alternatively, vapor deposition (VD) method produces uniform thin film but requires precise control of complex thermodynamic parameters which makes the technique unsuitable for large scale production. Most deposition techniques for perovskite require tedious surface optimization to improve the surface quality of deposits. Optimization of perovskite surface is necessary to significantly improve device structure and electrical output. In this review, electrodeposition of perovskite solar cell is demonstrated as a scalable and reproducible technique to fabricate uniform and smooth thin film surface that circumvents the need for high vacuum environment. Electrodeposition is achieved at low temperatures, supports precise control and optimization of deposits for efficient charge transfer.", "author_names": [ "Ukeme Charles", "Mohd Adib Ibrahim", "Mohd Asri Mat Teridi" ], "corpus_id": 103814375, "doc_id": "103814375", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Electrodeposition of organic inorganic tri halide perovskites solar cell", "venue": "", "year": 2018 }, { "abstract": "Organic inorganic halide perovskite solar cells (OIHPSCs) offer a fantastic opportunity to harness solar energy in a low cost and efficient way. This ambition for commercialization has been greatly encouraged by the surge in device performance from 3.8% in 2009 to the state of the art 22.7% For high device performance, tailoring the interfacial properties is demonstrated essentially important. Being in a molecular scale, the self assembly monolayers (SAMs) are proved a facile but effective tool for interface modification. And lots of studies have demonstrated that SAMs have a variety of positive effects for perovskite solar cells, including mediating the morphology, improving energy level alignment, passivating trap states, etc. In this mini review, we give an insightful summary on the recent application of SAMs in OIHPSCs, analyze the mechanisms to improve device performance, and provide guidance to SAM boosted perovskite solar cells for high performance and practical application. Finally, a landscape is depicted for future application of SAMs in perovskite solar cells.", "author_names": [ "Ru Qiao", "Lijian Zuo" ], "corpus_id": 103796747, "doc_id": "103796747", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Self assembly monolayers boosting organic inorganic halide perovskite solar cell performance", "venue": "", "year": 2018 }, { "abstract": "Understanding the defect structure in organic inorganic hybrid perovskite material (OHP) is a crucial role to explain several physical properties such as material stability, energy band, carrier mobility, and so on. In the solar cell applications using OHP, finding, understanding, and controlling defects is essential to making a more advanced device with high efficiency and stability. Naturally, we need to find, understand, and control the possible defects in OHP. However, the defect research field in OHP material is just beginning now. In this short review, we will explore the kinds of defects and their effects on OHP.", "author_names": [ "Young Mi Lee", "In-Hui Maeng", "Jinwoo Park", "Myungkwan Song", "Jung-Ho Yun", "Min-Cherl Jung", "Masakazu Nakamura" ], "corpus_id": 53796422, "doc_id": "53796422", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Comprehensive Understanding and Controlling the Defect Structures: An Effective Approach for Organic Inorganic Hybrid Perovskite Based Solar Cell Application", "venue": "Front. Energy Res.", "year": 2018 }, { "abstract": "Abstract When transferring photovoltaic technologies from laboratory scale fabrication to industrial applications, low cost, large area, high throughput, high solar to energy power conversion efficiency, long lifetime, and low toxicity are crucial attributes. In recent years, organic inorganic halide perovskite solar cells have emerged as a promising high performance, cost effective solar cell technology. However, most of the best reported efficiencies have been obtained on small active area devices ~0.1 cm 2 Therefore, development of protocols to industrialize such a technology is of paramount importance. In this article, we review the progress of perovskite solar cells with a particular emphasis on fabrication processes and instrumentation that have scale up potential. For successful commercialization, the capacity to fabricate large area modules is essential. Long term stability is discussed, focusing on lifetime measurement and quantification protocols for commercialization. Cost performance and life cycle assessment analysis based on recently reported state of the art perovskite solar cells are discussed. These analyses offer insights regarding required efficiency, module area size, and lifetime, in order for perovskite solar cells to be competitive with existing photovoltaic technologies. Finally, lead toxicity and possible solutions to this issue will be discussed. In the outlook, we outline future research directions based on reported results and trends in the field.", "author_names": [ "Longbin Qiu", "Luis K Ono", "Yabing Qi" ], "corpus_id": 139888494, "doc_id": "139888494", "n_citations": 146, "n_key_citations": 0, "score": 0, "title": "Advances and challenges to the commercialization of organic inorganic halide perovskite solar cell technology", "venue": "", "year": 2017 }, { "abstract": "Last few years, the perovskite materials have attracted great attention in organic inorganic solar cells due to their excellent light harvesting properties, tune able direct band gap, high molar extinction coefficient, high carrier mobility. This platform makes new opportunities for the development of solution processed, high efficiency and low cost solar cells. The power conversion efficiency of perovskite based organic inorganic hybrid solar cells has now above 15% making it competitive with crystalline Si solar cells. This review summarised the current performance and drawback of perovskite materials in solar cell applications. Also the versatile synthesizes methods of perovskite thin film has been discussed in this article.", "author_names": [ "Mohammad Salim", "Shahadat Hussain Chowdhury", "Muhammad Salim Hossain", "M A Islam" ], "corpus_id": 55294780, "doc_id": "55294780", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A MICRO REVIEW ON PROSPECTS AND CHALLENGES OF PEROVSKITE MATERIALS IN ORGANIC INORGANIC HYBRID SOLAR CELL APPLICATIONS", "venue": "", "year": 2015 }, { "abstract": "Abstract Organometal lead halides perovskites are promising solar cells material due to their outstanding properties such as tuneable bandgap, impressive tolerance to defects, long exciton diffusion length, high carrier mobility and absorption coefficient. Up to now, the organometal lead halides based solar cells (PSCs) have demonstrated impressive power conversion efficiency reaching 25.2% (not stabilised) However, their operating life times are limited due to degradation of the organic components under some environmental conditions. Therefore, researchers have focused their interest on the all inorganic perovskite; especially on the caesium lead triiodide perovskite (CsPbI3) which exhibits a better compositional and chemical stability. Nevertheless, the phase instability of the black phase of this material constitutes its main limitation for its use in the solar cell devices production. This review aims to present the most impactful research giving insights on the factors that may cause the instability of all inorganic lead halide perovskite materials, as well as the instability of the whole device. In addition to deposition methods, the composition, structure and optical properties of inorganic perovskite materials have also been presented. Furthermore, this review highlights the different strategies used in order to improve the phase stability of caesium lead halide perovskite material through either engineering on the material structure or the fabrication method.", "author_names": [ "Nabonswende Aida Nadege Ouedraogo", "Yichuan Chen", "Yueyue Xiao", "Qi Meng", "Chang Bao Han", "Hui Yan", "Yongzhe Zhang" ], "corpus_id": 209703010, "doc_id": "209703010", "n_citations": 45, "n_key_citations": 0, "score": 0, "title": "Stability of all inorganic perovskite solar cells", "venue": "", "year": 2020 } ]

[ { "abstract": "Advanced beyond silicon electronic technology requires both channel materials and also ultralow resistance contacts to be discovered1,2. Atomically thin two dimensional semiconductors have great potential for realizing high performance electronic devices1,3. However, owing to metal induced gap states (MIGS)4 7, energy barriers at the metal semiconductor interface which fundamentally lead to high contact resistance and poor current delivery capability have constrained the improvement of two dimensional semiconductor transistors so far2,8,9. Here we report ohmic contact between semimetallic bismuth and semiconducting monolayer transition metal dichalcogenides (TMDs) where the MIGS are sufficiently suppressed and degenerate states in the TMD are spontaneously formed in contact with bismuth. Through this approach, we achieve zero Schottky barrier height, a contact resistance of 123 ohm micrometres and an on state current density of 1,135 microamps per micrometre on monolayer MoS2; these two values are, to the best of our knowledge, the lowest and highest yet recorded, respectively. We also demonstrate that excellent ohmic contacts can be formed on various monolayer semiconductors, including MoS2, WS2 and WSe2. Our reported contact resistances are a substantial improvement for two dimensional semiconductors, and approach the quantum limit. This technology unveils the potential of high performance monolayer transistors that are on par with state of the art three dimensional semiconductors, enabling further device downscaling and extending Moore's law.", "author_names": [ "Pin-Chun Shen", "Cong Su", "Yuxuan Lin", "Ang-Sheng Chou", "Chao-Ching Cheng", "Ji-Hoon Park", "Ming-Hui Chiu", "Ang-Yu Lu", "Hao-Ling Tang", "Mohammad Mahdi Tavakoli", "Gregory Pitner", "Xiang Ji", "Zhengyang Cai", "Nannan Mao", "Jiangtao Wang", "Vincent C Tung", "Ju Li", "Jeffrey Bokor", "Alex Zettl", "Chih-I Wu", "Tomas Palacios", "Lain-Jong Li", "Jing Kong" ], "corpus_id": 234486831, "doc_id": "234486831", "n_citations": 10, "n_key_citations": 1, "score": 1, "title": "Ultralow contact resistance between semimetal and monolayer semiconductors.", "venue": "Nature", "year": 2021 }, { "abstract": "In the post Moore era, it is well known that contact resistance has been a critical issue in determining the performance of complementary metal oxide semiconductor (CMOS) reaching physical limits. Conventional Ohmic contact techniques, however, have hindered rather than helped the development of CMOS technology reaching its limits of scaling. Here, a novel conductive filament metal interlayer semiconductor (CF MIS) contact which achieves ultralow contact resistance by generating CFs and lowering Schottky barrier height (SBH) is investigated for potential applications in various nanodevices in lieu of conventional Ohmic contacts. This universal and innovative technique, CF MIS contact, forming the CFs to provide a quantity of electron paths as well as tuning SBH of semiconductor is first introduced. The proposed CF MIS contact achieves ultralow specific contact resistivity, exhibiting up to ~x700 000 reduction compared to that of the conventional metal semiconductor contact. This study proves the viability of CF MIS contacts for future Ohmic contact schemes and that they can easily be extended to mainstream electronic nanodevices that suffer from significant contact resistance problems.", "author_names": [ "Seung-Hwan Kim", "Gwang-Sik Kim", "June Park", "Changmin Lee", "Hyoungsub Kim", "Jiyoung Kim", "Joon Hyung Shim", "Hyun-Yong Yu" ], "corpus_id": 51623219, "doc_id": "51623219", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Novel Conductive Filament Metal Interlayer Semiconductor Contact Structure for Ultralow Contact Resistance Achievement.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "We report on the electrical and microstructural characterization of Au free Ti/Al/Ti/TiN contacts for AlGaN/GaN heterostructures. Ultra low Au free ohmic contact has been obtained with contact resistance and specific contact resistivity as low as <inline formula> <tex math notation=\"LaTeX\"$0.21~\\Omega \\cdot \\text{mm} /tex math>/inline formula> and <inline formula> <tex math notation=\"LaTeX\"{1.16}\\times {10} 6} \\Omega \\cdot \\text{cm}{2} /tex math>/inline formula> respectively. The ohmic alloy temperature is reduced as low as 550 degC by pre ohmic recess of the AlGaN barrier and optimization of the thickness of bottom Ti layer. We found that interfacial layer formation of AlN between the ohmic metal and AlGaN surface is crucial to realize a low contact resistance with reduced low annealing temperature by a combination of electrical <inline formula> <tex math notation=\"LaTeX\"{I} /tex math>/inline formula> <inline formula> <tex math notation=\"LaTeX\"{V} /tex math>/inline formula> characterization and high resolution transmission electron microscopy analysis. Furthermore, we suggest a hypothesis that the bottom Ti layer plays a catalytic role for the Al N reaction with optimized thickness.", "author_names": [ "Jinhan Zhang", "Xuanwu Kang", "Xinhua Wang", "Sen Huang", "C Chen", "Ke Wei", "Yingkui Zheng", "Qi Zhou", "Wanjun Chen", "Bo Zhang", "Xinyu Liu" ], "corpus_id": 46898340, "doc_id": "46898340", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Ultralow Contact Resistance Au Free Ohmic Contacts With Low Annealing Temperature on AlGaN/GaN Heterostructures", "venue": "IEEE Electron Device Letters", "year": 2018 }, { "abstract": "The electrical performance of graphene based devices is largely limited by substantial contact resistance at the heterodimensional graphene metal junctions. A laser assisted nanowelding technique is developed to reduce graphene metal (G M) contact resistance and improve carrier injection in suspended graphene devices. Selective breakdown of CC bonds and formation of structural defects are realized through laser irradiation at the edges of graphene within the G M contact regions in order to increase the chemical reactivity of graphene, facilitate G M bonding, and, therefore, maximize interfacial carrier transportation. Through this method, significantly reduced G M contact resistances, as low as 2.57 O um are obtained. In addition, it is demonstrated that the location of laser induced defects within the contact areas significantly impacts the interfacial properties and the carrier mobility of graphene devices. A fourfold increase in photocurrent is observed in the suspended graphene photodetectors with treated G M interfaces as compared to ordinary ones. This contact free and position selective technique minimizes the degradation of the graphene channels and maintains the superior performance of graphene devices, making it a promising approach for reducing G M resistance in the fabrication of graphene based devices.", "author_names": [ "Kamran Keramatnejad", "Yunsheng Zhou", "Dawei Li", "Hossein Rabiee Golgir", "Xi Huang", "Qi Ming Zhou", "Jingfeng Song", "Stephen Ducharme", "Yongfeng Lu" ], "corpus_id": 135922907, "doc_id": "135922907", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Laser Assisted Nanowelding of Graphene to Metals: An Optical Approach toward Ultralow Contact Resistance", "venue": "", "year": 2017 }, { "abstract": "Heteroepitaxial growth of Cr metal on Nb doped SrTiO3(001) is accompanied by Cr diffusion to interstitial sites within the first few atomic planes, an anchoring of the Cr film to the substrate, charge transfer from Cr to Ti, and metallization of the near surface region, as depicted in the figure. The contact resistance of the resulting interface is exceedingly low.", "author_names": [ "Scott A Chambers", "Meng Gu", "Peter V Sushko", "Hao Yang", "Chongmin Wang", "Nigel D Browning" ], "corpus_id": 205249727, "doc_id": "205249727", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Ultralow contact resistance at an epitaxial metal/oxide heterojunction through interstitial site doping.", "venue": "Advanced materials", "year": 2013 }, { "abstract": "We show that the parasitic contact resistance in staggered organic thin film transistors employing a solid electrolyte as the gate dielectric is around RC=10 O cm, two orders of magnitude lower than in conventional devices. Moreover, this parameter is only weakly dependent on the thickness of the semiconductor and on the nature of the metal/semiconductor pair. This unique feature of an electrolyte gated transistor results from the electrochemical doping of the active layer occurring under the influence of the applied gate bias.", "author_names": [ "Daniele Braga", "Min-Woo Ha", "Wei Xie", "C Daniel Frisbie" ], "corpus_id": 121004159, "doc_id": "121004159", "n_citations": 80, "n_key_citations": 1, "score": 0, "title": "Ultralow contact resistance in electrolyte gated organic thin film transistors", "venue": "", "year": 2010 }, { "abstract": "Abstract Low dimensional silicon based materials have shown a great potential for thermoelectric applications due to their enhanced figure of merit ZT and high technology compatibility. However, their implementation in real devices remains highly challenging due to the associated large contact resistances (thermal and electrical) Herein we demonstrate ultralow contact resistance silicon nanowires epitaxially grown on scalable devices with enhanced ZT. Temperature dependent figure of merit was fully determined for monolithically integrated individual silicon nanowires achieving a maximum value of ZT 0.2 at 620 K. Sidewise, this work accounts for the first time nearly zero thermal and electrical contact resistances in monolithically integrated bottom up nanowires.", "author_names": [ "Gerard Gadea Diez", "Jose Manuel Sojo Gordillo", "Merce Pacios Pujado", "Marc Salleras", "Luis Fonseca", "Alex Morata", "Albert Tarancon Rubio" ], "corpus_id": 210750176, "doc_id": "210750176", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Enhanced thermoelectric figure of merit of individual Si nanowires with ultralow contact resistances", "venue": "", "year": 2020 }, { "abstract": "A metal resistance aware transmission line model (MRA TLM) is developed to eliminate the parasitic metal resistance from the extraction of specific contact resistivity <inline formula> <tex math notation=\"LaTeX\"\\rho _{c} /tex math>/inline formula> in the metal/semiconductor contact. The proposed MRA TLM is verified by Synopsys technology computer aided design (TCAD) simulation, and a superior extraction accuracy as compared to the conventional TLM based method is achieved. The proposed MRA TLM is experimentally demonstrated in the metal/p<sup>/sup> Ge_0.95Sn_0.05 (p<sup>/sup> GeSn) contacts. Ultralow <inline formula> <tex math notation=\"LaTeX\"\\rho _{c} /tex math>/inline formula> values of <inline formula> <tex math notation=\"LaTeX\"{7.5} \\times {10} {10} /tex math>/inline formula> and <inline formula> <tex math notation=\"LaTeX\"{2.1} \\times {10} {9} \\Omega \\cdot \\text {cm}{2} /tex math>/inline formula> are extracted by MRA TLM for Ni/p<sup>/sup> GeSn and Ti/p<sup>/sup> GeSn contacts, respectively, which are in good agreement with <inline formula> <tex math notation=\"LaTeX\"{9.5} \\times {10} {10} /tex math>/inline formula> and <inline formula> <tex math notation=\"LaTeX\"{2.6} \\times {10} {9} \\Omega \\cdot \\text {cm}{2} /tex math>/inline formula> extracted numerically by the two layer distributed resistor network model (TDM) qualifying the proposed MRA TLM for the extraction of ultralow <inline formula> <tex math notation=\"LaTeX\"\\rho _{c} /tex math>/inline formula> down to sub <inline formula> <tex math notation=\"LaTeX\"$10^ {9}\\Omega \\cdot \\text {cm}{2} /tex math>/inline formula> regime. In contrast, the <inline formula> <tex math notation=\"LaTeX\"\\rho _{c} /tex math>/inline formula> extracted by the conventional TLM based method is more than three times higher due to the parasitic metal resistance.", "author_names": [ "Ying Wu", "Haiwen Xu", "Xiao Gong", "Yee-Chia Yeo" ], "corpus_id": 195065029, "doc_id": "195065029", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Elimination of the Parasitic Metal Resistance in Transmission Line Model for Extraction of Ultralow Specific Contact Resistivity", "venue": "IEEE Transactions on Electron Devices", "year": 2019 }, { "abstract": "Ultralow contact resistance of metal silicide n+ Si contact has been achieved by a novel contact metallization process employing Ta silicidation of a n+ Si contact surface by a Si capping silicidation technique. The Si capping silicidation has been employed to realize an ultraclean silicidation. The as deposited Ta surface is in situ covered with a very thin Si protection layer in order to prevent the metal surface from being oxidized or contaminated. By combining the oxide layer free Si/metal on Si deposition process and an ultraclean ion implantation for mixing, metal silicide n+Si structure has been formed by low temperature thermal annealing in an ultraclean Ar gas. As a result, an ultralow contact resistivity of 5.8x10 9 (O cm2) has been achieved.", "author_names": [ "Keiichi Yamada", "Kazuo Tomita", "Tadahiro Ohmi" ], "corpus_id": 95170717, "doc_id": "95170717", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Formation of metal silicide silicon contact with ultralow contact resistance by silicon capping silicidation technique", "venue": "", "year": 1994 }, { "abstract": "In this brief, the high quality carbon nanotubes (CNTs) is grown by a chemical vapor deposition (CVD) method, and it is used as an ultrafine flip chip interconnection material in the proposed 3 D integrated circuit (3DIC) system. We show a patterned growth of multiwalled CNTs on the substrate with prestructured bond pads including a complete metallization system for an electrical characterization. We succeeded in achieving reliable flip chip connections between CNT covered contact pads and metal pads during the room temperature bonding process. The goal is a reversible electrical and mechanical chip assembly with CNT bumps. Based on the current voltage <inline formula> <tex math notation=\"LaTeX\"{I} /tex math>/inline formula> <inline formula> <tex math notation=\"LaTeX\"{V} /tex math>/inline formula> measurements, the resistivity <inline formula> <tex math notation=\"LaTeX\"\\rho /tex math>/inline formula> of the grown CNTs is found to be close to <inline formula> <tex math notation=\"LaTeX\"\\sim 10^ {6}\\sf \\Omega \\text{m} /tex math>/inline formula> With the proposed 3DIC process flow, the vertically electrical connection between two different Si substrates is demonstrated successfully. The connection resistance in the full 3 D system is very promising <inline formula> <tex math notation=\"LaTeX\"\\sim 2.43~\\sf \\Omega /tex math>/inline formula> compared with other's work <inline formula> <tex math notation=\"LaTeX\"\\sim 12~\\sf \\Omega /tex math>/inline formula> The different bonding materials (In versus Sn) and bonding times are also investigated systemically and further optimized. This brief provides a useful solution for the future electrical connection in the high performance and high dense 3 D integrated devices.", "author_names": [ "M -H Liao", "P Y Lu", "W -J Su", "S -C Chen", "H T Hung", "C Robert Kao", "W -C Pu", "C -C A Chen", "M -H Lee" ], "corpus_id": 216103532, "doc_id": "216103532", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The Demonstration of Carbon Nanotubes (CNTs) as Flip Chip Connections in 3 D Integrated Circuits With an Ultralow Connection Resistance", "venue": "IEEE Transactions on Electron Devices", "year": 2020 } ]

[ { "abstract": "Abstract It is a remarkable and straightforward approach to customize the dispersion and nonlinear properties of the photonic devices without varying the composition of the material by employing periodic segmented waveguide structures at the subwavelength level of the operational wavelength. This method addresses the diffraction limit and it is likely to engineer the waveguides as a uniform optical medium with an effective refractive index that relies on the waveguide geometry. In recent years, advances in lithographic technology in the semiconductor on insulator platform providing sub 100 nm patterning resolution have been renowned with many useful devices based on subwavelength structures. At the beginning of the paper, the modal characteristics of the subwavelength grating (SWG) waveguides are presented. And in afterwards, we provide an insight into noteworthy progress in the subwavelength grating (SWG) waveguides based devices for signal processing and sensing applications such as ring resonators for surface and bulk sensing, couplers, suspended membrane waveguides for mid infrared applications, filters, and fiber to chip couplers.", "author_names": [ "Nikolay Lvovich Kazanskiy", "Muhammad Ali Butt", "Svetlana Nikolaevna Khonina" ], "corpus_id": 232540670, "doc_id": "232540670", "n_citations": 7, "n_key_citations": 0, "score": 1, "title": "Silicon photonic devices realized on refractive index engineered subwavelength grating waveguides A review", "venue": "", "year": 2021 }, { "abstract": "Periodic silicon waveguides with a pitch that is below half the effective wavelength of light support diffraction less Bloch modes. These modes propagate as through a homogeneous, artificial core metamaterial waveguide whose optical characteristics can be engineered by lithographic patterning. Subwavelength gratings (SWGs) provide designers with unique tools to control the refractive index, dispersion and birefringence of the equivalent metamaterial, yielding improved device performance. Based on this approach many high performance optical devices have been designed and experimentally demonstrated in the last years. In this paper we will review the fundamentals of SWG engineering and present some of our latest findings.", "author_names": [ "Inigo Molina-Fernandez", "Abdelfettah Hadij-ElHouati", "Jose Manuel Luque-Gonzalez", "Daniel Pereira", "Alejandro Sanchez Postigo", "Gonzalo Wanguenmert-Perez", "Alejandro Ortega-Monux", "Robert Halir", "Jose de Oliva Rubio", "Jens H Schmid", "Pavel Cheben", "Jiri Ctyroky" ], "corpus_id": 233827887, "doc_id": "233827887", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Subwavelength grating silicon photonic devices", "venue": "", "year": 2021 }, { "abstract": "Surface grating couplers are fundamental components in chip based photonic devices to couple light between photonic integrated circuits and optical fibers. In this work, we report on a grating coupler with sub decibel experimental coupling efficiency using a single etch process in a standard 220 nm silicon on insulator (SOI) platform. We specifically demonstrate a subwavelength metamaterial refractive index engineered nanostructure with backside metal reflector, with the measured peak fiber chip coupling efficiency of 0.69 dB (85.3% and 3 dB bandwidth of 60 nm. This is the highest coupling efficiency hitherto experimentally achieved for a surface grating coupler implemented in 220 nm SOI platform.", "author_names": [ "Daniel Benedikovic", "Pavel Cheben", "Jens H Schmid", "Dan-Xia Xu", "Boris Lamontagne", "Shurui Wang", "Jean Lapointe", "Robert Halir", "Alejandro Ortega-Monux", "Siegfried Janz", "Milan Dado" ], "corpus_id": 3089094, "doc_id": "3089094", "n_citations": 93, "n_key_citations": 1, "score": 0, "title": "Subwavelength index engineered surface grating coupler with sub decibel efficiency for 220 nm silicon on insulator waveguides.", "venue": "Optics express", "year": 2015 }, { "abstract": "Abstract Subwavelength structures such as subwavelength gratings (SWGs) and subwavelength metamaterials are capable of tailoring the optical properties of materials and controlling the flow of light at the nanoscale. The effective indices of the subwavelength structured strip and slab waveguides can be changed in a wide range by choosing an appropriate duty cycle or a filling factor of silicon, which provides an effective method to manipulate the optical field and achieve effective index matching for functional devices. Recent advances in nanofabrication techniques have made it possible to implement subwavelength structures in silicon strip and slab waveguides. Here we review various approaches used to design subwavelength structures and achieve exotic optical responses and discuss how these structures can be used to realize high performance silicon photonic devices. Both one dimensional SWG devices and two dimensional subwavelength metamaterial devices are covered in this review, including subwavelength structure based polarization handling devices, mode manipulation devices, and building blocks for integrated optical interconnects. Perspectives on subwavelength structured silicon photonic devices are also discussed.", "author_names": [ "Lu Sun", "Yong Zhang", "Yu He", "Hongwei Wang", "Yikai Su" ], "corpus_id": 219041917, "doc_id": "219041917", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Subwavelength structured silicon waveguides and photonic devices", "venue": "", "year": 2020 }, { "abstract": "In the past decade, there has been tremendous progress in using subwavelength scale nanostructures with elaborately designed periodic and disordered photonic materials for applications in integrated photonics. In this paper, we review the advances in subwavelength engineering used in silicon photonic devices, with an emphasis on our own contributions on the use of subwavelength gratings and hyperuniform disordered photonic structures to attain state of the art performances for near and mid infrared applications in fiber chip coupling, slot waveguides for refractive index sensing, mode conversion, wavelength filtering, integrated resonators, and ultracompact high extinction and broadband integrated polarizers.", "author_names": [ "Wen Zhou", "Zhenzhou Cheng", "Xia Chen", "Ke Xu", "Xiankai Sun", "Hon Ki Tsang" ], "corpus_id": 85496846, "doc_id": "85496846", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Subwavelength Engineering in Silicon Photonic Devices", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2019 }, { "abstract": "The subwavelength patterning of planar structures is now widely used in silicon photonics, enabling the synthesis of metamaterials with engineered optical properties, including refractive index, dispersion, and anisotropy. A wide range of integrated devices based on subwavelength grating (SWG) metamaterials have been demonstrated at telecom wavelengths, some with unprecedented performance. The benefits of SWG metamaterials can be leveraged not only in the typical telecom near infrared bands, but also at the longer mid infrared wavelengths. In this invited presentation, we will review our latest developments in SWG based silicon and germanium photonic devices for the near and the midinfrared.", "author_names": [ "Alejandro Sanchez-Postigo", "J Gonzalo Wanguemert-Perez", "Alejandro Ortega-Monux", "Robert Halir", "Daniel Pereira-Martin", "Jose Manuel Luque-Gonzalez", "Jens H Schmid", "Shurui Wang", "Martin Vachon", "Dan-Xia Xu", "Jordi Soler Penades", "Milos S Nedeljkovic", "Goran Z Mashanovich", "Pavel Cheben", "Inigo Molina-Fernandez" ], "corpus_id": 233846828, "doc_id": "233846828", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Subwavelength grating metamaterial integrated devices for the near and mid infrared wavelengths", "venue": "OPTO", "year": 2021 }, { "abstract": "Subwavelength grating (SWG) waveguides are integrated photonic structures with a pitch substantially smaller than wavelength for which they are designed, so that diffraction effects are suppressed. SWG operates as an artificial metamaterial with an equivalent refractive index which depends on the geometry of the structure and the polarization of the propagating wave. SWG waveguides have been advantageously used in silicon photonics, resulting in significant performance improvements for many practical devices, including highly efficient fiber chip couplers, waveguide crossings, broadband multimode interference (MMI) couplers, evanescent field sensors and polarization beam splitters, to name a few. Here we present a theoretical and experimental study of the influence of disorder effects in SWG waveguides. We demonstrate via electromagnetic simulations and experimental measurements that even a comparatively small jitter ~5 nm) in the position and size of the SWG segments may cause a dramatic reduction in the transmittance for wide (multimode) SWG waveguides, while for narrow (single mode) waveguides this effect is negligible. Our study shows that the impact of the jitter on SWG waveguide performance is directly related to the modal confinement. (c) 2017 Optical Society of America OCIS codes: (130.0130) Integrated optics; (250.5300) Photonic integrated circuits; (130.3120) Integrated optics devices; (050.6624) Subwavelength structures; (160.3918) Metamaterials. References and links 1. S. M. Rytov, \"The electromagnetic properties of finely layered medium,\" Sov. Phys. JETP 2, 466 475 (1956) 2. M. W. Farn, \"Binary gratings with increased efficiency,\" Appl. Opt. 31(22) 4453 4458 (1992) 3. P. Cheben, D. X. Xu, S. Janz, and A. Densmore, \"Subwavelength waveguide grating for mode conversion and light coupling in integrated optics,\" Opt. Express 14(11) 4695 4702 (2006) 4. P. Cheben, P. J. Bock, J. H. Schmid, J. Lapointe, S. Janz, D. X. Xu, A. Densmore, A. Delage, B. Lamontagne, and T. J. Hall, \"Refractive index engineering with subwavelength gratings for efficient microphotonic couplers and planar waveguide multiplexers,\" Opt. Lett. 35(15) 2526 2528 (2010) 5. P. Cheben, J. H. Schmid, S. Wang, D. X. Xu, M. Vachon, S. Janz, J. Lapointe, Y. Painchaud, and M. J. Picard, \"Broadband polarization independent nanophotonic coupler for silicon waveguides with ultra high efficiency,\" Opt. Express 23(17) 22553 22563 (2015) 6. D. Benedikovic, P. Cheben, J. H. Schmid, D. X. Xu, B. Lamontagne, S. Wang, J. Lapointe, R. Halir, A. OrtegaMonux, S. Janz, and M. Dado, \"Subwavelength index engineered surface grating coupler with sub decibel efficiency for 220 nm silicon on insulator waveguides,\" Opt. Express 23(17) 22628 22635 (2015) 7. D. Benedikovic, C. Alonso Ramos, P. Cheben, J. H. Schmid, S. Wang, R. Halir, A. Ortega Monux, D. X. Xu, L. Vivien, J. Lapointe, S. Janz, and M. Dado, \"Single etch subwavelength engineered fiber chip grating couplers for 1.3 mm datacom wavelength band,\" Opt. Express 24(12) 12893 12904 (2016) 8. X. Xu, H. Subbaraman, J. Covey, D. Kwong, A. Hosseini, and R. T. Chen, \"Complementary metal oxide semiconductor compatible high efficiency subwavelength grating couplers for silicon integrated photonics,\" Appl. Phys. Lett. 101(3) 031109 (2012) 9. A. Sanchez Postigo, J. Gonzalo Wanguemert Perez, J. M. Luque Gonzalez, I. Molina Fernandez, P. Cheben, C. A. Alonso Ramos, R. Halir, J. H. Schmid, and A. Ortega Monux, \"Broadband fiber chip zero order surface grating coupler with 0.4 dB efficiency,\" Opt. Lett. 41(13) 3013 3016 (2016) Vol. 25, No. 11 29 May 2017 OPTICS EXPRESS 12222", "author_names": [ "", "S H", "F" ], "corpus_id": 195887339, "doc_id": "195887339", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Disorder effects in subwavelength grating metamaterial waveguides", "venue": "", "year": 2019 }, { "abstract": "In this review, we summarize and discuss our recent studies of subwavelength grating (SWG) structures for engineering the refractive index of silicon microphotonic waveguides. The SWG effect allows control of the effective refractive index of a waveguide core over a range spanning the values of the cladding material and silicon by lithographic patterning. We demonstrate this effect with the example of segmented photonic wire waveguides, which are shown to exhibit low propagation loss, and can be used to make highly efficient waveguide crossings and in plane fiber chip coupling structures. Other applications of SWG structures in silicon photonic waveguide devices include surface grating couplers with enhanced performance and simplified fabrication requirements, as well as a novel curved waveguide sidewall grating micro spectrometer, in which an SWG structure fulfills a dual purpose by acting as an effective slab waveguide for diffracted light and as a lateral cladding for a channel waveguide.", "author_names": [ "Jens H Schmid", "Pavel Cheben", "Przemek J Bock", "Robert Halir", "Jean Lapointe", "Siegfried Janz", "Andre Delage", "Adam Densmore", "Jean-Marc Fedeli", "Trevor J Hall", "Boris Lamontagne", "Rubin Ma", "Inigo Molina-Fernandez", "D-X Xu" ], "corpus_id": 26310523, "doc_id": "26310523", "n_citations": 40, "n_key_citations": 0, "score": 0, "title": "Refractive Index Engineering With Subwavelength Gratings in Silicon Microphotonic Waveguides", "venue": "IEEE Photonics Journal", "year": 2011 }, { "abstract": "Silicon photonics has emerged as an intense field of research due to its unique capabilities to integrate photonics and electronics into the same platform using standard semiconductor fabrication facilities. Subwavelength grating (SWG) structures, i.e. periodic nanostructured waveguides with a pitch below half the wavelength of light, allow the lossless propagation of Bloch Floquet modes which closely resemble propagation through a homogenous waveguide with optical properties (refractive index, dispersion, birefringence) that can be tailored to fulfill specific design goals. SWG engineering is now routinely used for novel and advanced device design. Fiber chip couplers, polarization and mode multiplexers, multimode interference couplers (MMIs) lenses, and bragg filters have been successfully designed in our group based in these concepts. In this invited talk we will review some of our last advances in the field.", "author_names": [ "Inigo Molina-Fernandez", "J Gonzalo Wanguemert-Perez", "Alejandro Ortega-Monux", "Robert Halir", "Jose de Oliva Rubio", "Alejandro Sanchez-Postigo", "Jose Manuel Luque-Gonzalez", "Abdelfettah Hadij-ElHouati", "Daniel Pereira-Martin", "David Gonzalez-Andrade", "Aitor V Velasco", "Alaine Herrero-Bermello", "Jens H Schmid", "Pavel Cheben", "Jiri Ctyroky" ], "corpus_id": 214262667, "doc_id": "214262667", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Silicon subwavelength waveguiding devices", "venue": "OPTO", "year": 2020 }, { "abstract": "High performance couplers are highly desired in many applications, but the design is limited by nearly unchangeable material refractive index. To tackle this issue, refractive index engineering method is investigated, which can be realized by subwavelength grating. Subwavelength gratings are periodical structures with pitches small enough to locally synthesize the refractive index of photonic waveguides, which allows direct control of optical profile as well as easier fabrication process. This review provides an introduction to the basics of subwavelength structures and pay special attention to the design strategies of some representative examples of subwavelength grating devices, including: edge couplers, fiber chip grating couplers, directional couplers and multimode interference couplers. Benefited from the subwavelength grating which can engineer the refractive index as well as birefringence and dispersion, these devices show better performance when compared to their conventional counterparts.", "author_names": [ "Lu Liu", "Zhiping James Zhou" ], "corpus_id": 125674430, "doc_id": "125674430", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Refractive index engineering of high performance coupler for compact photonic integrated circuits", "venue": "", "year": 2017 } ]

[ { "abstract": "We report a method to form multifunctional polymer coatings through simple dip coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self polymerization to form thin, surface adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad layers, including self assembled monolayers through deposition of long chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.", "author_names": [ "Haeshin Lee", "Shara M Dellatore", "William M Miller", "Phillip B Messersmith" ], "corpus_id": 206509131, "doc_id": "206509131", "n_citations": 6612, "n_key_citations": 116, "score": 1, "title": "Mussel Inspired Surface Chemistry for Multifunctional Coatings", "venue": "Science", "year": 2007 }, { "abstract": "", "author_names": [ "Haeshin Lee" ], "corpus_id": 97873978, "doc_id": "97873978", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Multifunctional Coatings Mussel Inspired Surface Chemistry for", "venue": "", "year": 2007 }, { "abstract": "Abstract Mussel inspired surface modification has been received great attention due to the universal adhesive properties of catechols for fabrication of multifunctional coatings, especially for gluing hydrophilic polymers to fabricate underwater superoleophobic materials utilizing in oil/water separation. Despite the extensive research carried out on this topic, the similarity and discrepancy between catecholamine and catecholic amino acid on surface modification and post functionalization have not been fully addressed yet. In this work, underwater superoleophobic surfaces have been successfully developed by a two step dip coating method with mussel inspired coatings and subsequent zwitterionic sulfobetaine methacrylate (SBMA) grafting onto stainless steel meshes and used in oil/water separation. Here, dopamine and 3,4 dihydroxy L phenylalanine were both served as mussel adhesives. More specifically, small molecule zwitterion rather than polyzwitterion was functionalized onto mussel inspired coatings to minimize the effect of surface topography on surface wettability. The modified surfaces were characterized by scanning electron microscopy (SEM) atomic force microscopy (AFM) and contact angle measurements to observe the surface morphology, estimate the surface roughness, and evaluate the wettability, respectively. It showed that SBMA modified meshes with polydopamine (PDA) or poly(3,4 dihydroxy L phenylalanine) (PDOPA) layer possessed quite different surface roughness, while both presented excellent oil repellency in water with underwater oil contact angles of 153deg 160deg, indicating a less dependence on surface roughness. Although by using the small molecule as the hydrophilic functionalized groups, the as prepared meshes exhibited good self cleaning and oil/water separation performance (separation efficiency >98% for hexane and >97% for soybean oil) and outstanding recyclability with 98% separation efficiency after 30 cycles. This method provides insight into different properties of polycatechols and simplifies the fabrication process through the use of small molecule zwitterion rather than zwitterionic polymer. Besides, the modified meshes also exhibited excellent stability for long term use. The resulting underwater superoleophobicity and robust self cleaning ability promise an ideal candidate for oil/water separation and oil contamination restriction.", "author_names": [ "Xiaolu Chen", "Yadan Zhai", "Xia Han", "Honglai Liu", "Ying Hu" ], "corpus_id": 133497968, "doc_id": "133497968", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Surface chemistry dominated underwater superoleophobic mesh with mussel inspired zwitterionic coatings for oil/water separation and self cleaning", "venue": "Applied Surface Science", "year": 2019 }, { "abstract": "Heparin, an important polysaccharide, has been widely used for coatings of cardiovascular devices because of its multiple biological functions including anticoagulation and inhibition of intimal hyperplasia. In this study, surface heparinization of a commonly used 316L stainless steel (SS) was explored for preparation of a multifunctional vascular stent. Dip coating of the stents in an aqueous solution of dopamine and hexamethylendiamine (HD) (PDAM/HD) was presented as a facile method to form an adhesive coating rich in primary amine groups, which was used for covalent heparin immobilization via active ester chemistry. A heparin grafting density of about 900 ng/cm(2) was achieved with this method. The retained bioactivity of the immobilized heparin was confirmed by a remarkable prolongation of the activated partial thromboplastin time (APTT) for about 15 s, suppression of platelet adhesion, and prevention of the denaturation of adsorbed fibrinogen. The Hep PDAM/HD also presented a favorable microenvironment for selectively enhancing endothelial cell (EC) adhesion, proliferation, migration and release of nitric oxide (NO) and at the same time inhibiting smooth muscle cell (SMC) adhesion and proliferation. Upon subcutaneous implantation, the Hep PDAM/HD exhibited mitigated tissue response, with thinner fibrous capsule and less granulation formation compared to the control 316L SS. This number of unique functions qualifies the heparinized coating as an attractive alternative for the design of a new generation of stents.", "author_names": [ "Ying Yang", "Pengkai Qi", "Feng Wen", "Xiangyang Li", "Qin Xia", "Manfred F Maitz", "Zhilu Yang", "Ru Shen", "Qiufen Tu", "Nan Huang" ], "corpus_id": 5511478, "doc_id": "5511478", "n_citations": 88, "n_key_citations": 0, "score": 0, "title": "Mussel inspired one step adherent coating rich in amine groups for covalent immobilization of heparin: hemocompatibility, growth behaviors of vascular cells, and tissue response.", "venue": "ACS applied materials interfaces", "year": 2014 }, { "abstract": "After more than four billion years of evolution, nature has created a large number of fascinating living organisms, which show numerous peculiar structures and wonderful properties. Nature can provide sources of plentiful inspiration for scientists to create various materials and devices with special functions and uses. Since Messersmith proposed the fabrication of multifunctional coatings through mussel inspired chemistry, this field has attracted considerable attention for its promising and exiciting applications. Polydopamine (PDA) an emerging soft matter, has been demonstrated to be a crucial component in mussel inspired chemistry. In this review, the recent developments of PDA for mussel inspired surface modification are summarized and discussed. The biomedical applications of PDA based materials are also highlighted. We believe that this review can provide important and timely information regarding mussel inspired chemistry and will be of great interest for scientists in the chemistry, materials, biology, medicine and interdisciplinary fields.", "author_names": [ "Meiying Liu", "Guangjian Zeng", "Ke Wang", "Qing Wan", "Lei Tao", "Xiaoyong Zhang", "Yen Wei" ], "corpus_id": 35107757, "doc_id": "35107757", "n_citations": 352, "n_key_citations": 2, "score": 0, "title": "Recent developments in polydopamine: an emerging soft matter for surface modification and biomedical applications.", "venue": "Nanoscale", "year": 2016 }, { "abstract": "Mussel inspired chemistry has been broadly exploited for multifunctional coatings in the surface modification of applied materials. Polyphenols are ubiquitous in plant tissues and far less expensive than polydopamine for mussel inspired chemistry. Herein, we report a facile and effective method to modify porous membranes via the co deposition of catechol (CCh) and polyethyleneimine (PEI) The membrane structures and properties were investigated by ATR/FTIR, XPS, FESEM, zeta potential, water contact angle and pure water flux measurements. The results reveal that the membranes deposited with a CCh PEI mass ratio of 1:0.25 show excellent hydrophilicity, ultrahigh water permeation flux and distinguished surface charges. These membranes were used to decolorize anionic dye solutions during filtration with superior removal efficiencies of over 99% Moreover, they have good reusability over repeated operations with a simple regeneration process.", "author_names": [ "Wen-Ze Qiu", "Hao-Cheng Yang", "Ling-Shu Wan", "Zhi-kang Xu" ], "corpus_id": 93161437, "doc_id": "93161437", "n_citations": 107, "n_key_citations": 1, "score": 0, "title": "Co deposition of catechol/polyethyleneimine on porous membranes for efficient decolorization of dye water", "venue": "", "year": 2015 }, { "abstract": "Kang et al. \"Bioinspired single bacterial cell force spectroscopy' Langmuir, 2009, 25(17):9656 9659. Ku et al. \"General functionalization route for cell adhesion on non wetting surfaces' Biomaterials, 2010.31:2535 2541. Lee et al. \"Mussel inspired surface chemistry for multifunctional coatings\" Science, 2007, 318(5849) 1 10. Ku et al. \"Human endothelial cell growth on mussel inspiried nanofiber scaffold for vascular tissue engineering' Biomaterials, 2010, 31:9431 9437. Ozgen et al. \"Evaluation of long term transport ability of a bioartificial renal tubule device using LLC PK1 cells' Nephrol Dial Transplant, 2004, 19:2198 2207. The 5' SBE International Conference on Bioengineering and Nano technology, Singapore: Poster presentation on Aug. 3, 2010. Pre senter: Ming Ni. The 5\" SBE International Conference on Bioengineering and Nano technology, Singapore: Oral conference presentation on Aug. 4. 2010. Presenter: Daniele Zink. Seminar on Sep. 13, 2010 European Conference on Biomaterials, Tampere Finland. Presenter: Ming Ni. The 5' SBE International Conference on Bioengineering and Nano technology, Singapore: IBN Labtour on Aug. 3, 2010. Presenter: Daniele Zink. Doraiswamy, Matrix assisted pulsed laser evaporation of DOPA modified poly(ethylene glycol) thin films, J. Adhesion Sci Technol (2007) p. 1 13. Humes et al. Initial clinical results of the bioartificial kidney containing human cells in ICU patients with acute renal failure. Kidney Int 66:1578 1588 (2004) Ku et al. General functionalization route for cell adhesion on non wetting surfaces, Biomaterials, 31:2535 2541 (2010) Lee et al. Mussel Inspired Surface Chemistry for Multifunctional Coatings, Science, 318:426 (2007) Lee et al. A reversible wet/dry adhesive inspired by mussels and geckos, Nature, 448:338 (Jul. 19, 2007) Lee et al. Single molecule mechanics of mussel adhesion, PNAS, 103, 12999 13003 (Aug. 29, 2006) Ni et al. Characterization of membrane materials and membrane coatings for bioreactor units of bioartificial kidneys, Biomaterials, 32, pp. 1465 1476, 2011. (Continued)", "author_names": [ "Daniele Zink" ], "corpus_id": 208056282, "doc_id": "208056282", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "MEMBRANES OF BOARTIFICIAL, KIDNEYS", "venue": "", "year": 2017 }, { "abstract": "Abstract Plant inspired polyphenols are capable of forming substrate independent coatings for versatile functionalization via oxidative self polymerization in an alkalescent aqueous solution. However, shortcomings like low uniformity and lengthy reaction times discourage their large scale implementations. In this work, we report a benign surface modification method for the highly effective, inexpensive construction of catechol (CA) coatings using sodium periodate (SP) as a trigger. Compared with recent progress in polyphenol coatings, our strategy achieved by far the fastest superhydrophilic modification rate ever reported. UV vis spectroscopy, atomic force microscopy (AFM) and ellipsometry are used to gain insights into the reaction kinetics of oxidant triggered polymerization and deposition of CA. SP assisted CA films with good homogeneity were efficiently deposited on various dense and porous substrates. Ultimately, the unprecedentedly superhydrophilic/underwater superoleophobic coating layer was applied on the initially hydrophobic polyvinylidene fluoride (PVDF) membrane, endowing the porous membrane with extremely high pure water permeability, favorable heavy metal adsorption ability, and outstanding oil/water separation performance. Due to the chemical versatility of CA, we envision that this novel coating technique holds significant potentials in tailoring the surface properties of different materials for a wide range of applications.", "author_names": [ "Yulan Chen", "Qingxia Liu" ], "corpus_id": 105752200, "doc_id": "105752200", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Oxidant induced plant phenol surface chemistry for multifunctional coatings: Mechanism and potential applications", "venue": "", "year": 2019 }, { "abstract": "Specific selectivity of vascular cells and antithrombogenicity are crucial factors for the long term success of vascular implants. In this work, a novel concept of mussel inspired \"built up\" surface chemistry realized by sequential stacking of a copper dopamine network basement, followed by a polydopamine layer is introduced to facilitate the combination of nitric oxide (NO) catalysis and vascular cell selectivity. The resultant \"built up\" film allowed easy manipulation of the content of copper ions and the density of catechol/quinone groups, facilitating the multifunctional surface engineering of vascular devices. For example, the chelated copper ions in the copper dopamine network endow a functionalized vascular stent with a durable release of NO via catalytic decomposition of endogenous S nitrosothiol. Meanwhile, the catechol/quinone groups on the film surface allow the facile, secondary grafting of the REDV peptide to develop a selectivity for vascular cells, as a supplement to the functions of NO. As a result, the functionalized vascular stent perfectly combines the functions of NO and REDV, showing excellent antithrombotic properties and competitive selectivity toward the endothelial cells over the smooth muscle cells, hence impressively promotes re endothelialization and improves anti restenosis in vivo. Therefore, the first mussel inspired \"built up\" surface chemistry can be a promising candidate for the engineering of multifunctional surfaces.", "author_names": [ "Xiangyang Li", "Jingxia Liu", "Tong Yang", "Hua Qiu", "Lei Lu", "Qiufen Tu", "Kaiqin Xiong", "Nan Huang", "Zhilu Yang" ], "corpus_id": 211564642, "doc_id": "211564642", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Mussel inspired \"built up\" surface chemistry for combining nitric oxide catalytic and vascular cell selective properties.", "venue": "Biomaterials", "year": 2020 }, { "abstract": "In this work, surface functionalized microcapsules from porous carbon nanospheres (PCNs) were successfully prepared by mussel inspired chemistry with polydopamine (PDA) and metal free photoinduced electron transfer atom transfer radical polymerization (PET ATRP) These functional microcapsules are introduced into self healing hydrogels to enhance its mechanical strength. The PCNs synthesized by a simple soft template method are mixed with linseed oil (LO) for loading of the biomass healing agent and the microcapsules are first prepared by coating PDA. PDA coatings were used to immobilize ATRP initiator for initiating 4 vinylpyridine (4VP) on the surface of microcapsules by PET ATRP. Using these functional microcapsules, the self healing efficiency was about 92.5% after 4 hrs at ambient temperature and the healed tensile strength can be held at 2.5 MPa with a fracture strain of 625.2% All results indicated that the surface functionalized microcapsules for self healing hydrogels have remarkable biocompatibility and mechanical properties.", "author_names": [ "Dechao Fan", "Guang-lin Wang", "Anyao Ma", "Wenxiang Wang", "Hou Chen", "Liangjiu Bai", "Huawei Yang", "Donglei Wei", "Lixia Yang" ], "corpus_id": 206498784, "doc_id": "206498784", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Surface Engineering of Porous Carbon for Self Healing Nanocomposite Hydrogels by Mussel inspired Chemistry and PET ATRP.", "venue": "ACS applied materials interfaces", "year": 2019 } ]

[ { "abstract": "Two dimensional materials are attractive for use in next generation nanoelectronic devices because, compared to one dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16) previously reported mobilities in the 0.5 3 cm(2) V( 1) s( 1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room temperature single layer MoS(2) mobility of at least 200 cm(2) V( 1) s( 1) similar to that of graphene nanoribbons, and demonstrate transistors with room temperature current on/off ratios of 1 x 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.", "author_names": [ "Branimir Radisavljevic", "Aleksandra Radenovic", "Jacopo Brivio", "Valentina Giacometti", "Andras Kis" ], "corpus_id": 205446552, "doc_id": "205446552", "n_citations": 9689, "n_key_citations": 117, "score": 1, "title": "Single layer MoS2 transistors.", "venue": "Nature nanotechnology", "year": 2011 }, { "abstract": "Two dimensional materials are an emerging class of new materials with a wide range of electrical properties and potential practical applications. Although graphene is the most well studied two dimensional material, single layers of other materials, such as insulating BN (ref. 2) and semiconducting MoS2 (refs 3, 4) or WSe2 (refs 5, 6) are gaining increasing attention as promising gate insulators and channel materials for field effect transistors. Because monolayer MoS2 is a direct bandgap semiconductor due to quantum mechanical confinement, it could be suitable for applications in optoelectronic devices where the direct bandgap would allow a high absorption coefficient and efficient electron hole pair generation under photoexcitation. Here, we demonstrate ultrasensitive monolayer MoS2 phototransistors with improved device mobility and ON current. Our devices show a maximum external photoresponsivity of 880 A W( 1) at a wavelength of 561 nm and a photoresponse in the 400 680 nm range. With recent developments in large scale production techniques such as liquid scale exfoliation and chemical vapour deposition like growth, MoS2 shows important potential for applications in MoS2 based integrated optoelectronic circuits, light sensing, biomedical imaging, video recording and spectroscopy.", "author_names": [ "Oriol Lopez-Sanchez", "Dominik S Lembke", "M Kayci", "Aleksandra Radenovic", "Andras Kis" ], "corpus_id": 5435971, "doc_id": "5435971", "n_citations": 3092, "n_key_citations": 33, "score": 0, "title": "Ultrasensitive photodetectors based on monolayer MoS2.", "venue": "Nature nanotechnology", "year": 2013 }, { "abstract": "Novel physical phenomena can emerge in low dimensional nanomaterials. Bulk MoS(2) a prototypical metal dichalcogenide, is an indirect bandgap semiconductor with negligible photoluminescence. When the MoS(2) crystal is thinned to monolayer, however, a strong photoluminescence emerges, indicating an indirect to direct bandgap transition in this d electron system. This observation shows that quantum confinement in layered d electron materials like MoS(2) provides new opportunities for engineering the electronic structure of matter at the nanoscale.", "author_names": [ "Andrea Splendiani", "Liang Sun", "Yuanbo Zhang", "Tianshu Li", "Jonghwan Kim", "Chi Yung Chim", "Giulia Galli", "Feng Wang" ], "corpus_id": 1353329, "doc_id": "1353329", "n_citations": 5858, "n_key_citations": 71, "score": 0, "title": "Emerging photoluminescence in monolayer MoS2.", "venue": "Nano letters", "year": 2010 }, { "abstract": "Abstract Designing and constructing bifunctional electrocatalysts is vital for water splitting. Particularly, the rational interface engineering can effectively modify the active sites and promote the electronic transfer, leading to the improved splitting efficiency. Herein, free standing and defect rich heterogeneous MoS2/NiS2 nanosheets for overall water splitting are designed. The abundant heterogeneous interfaces in MoS2/NiS2 can not only provide rich electroactive sites but also facilitate the electron transfer, which further cooperate synergistically toward electrocatalytic reactions. Consequently, the optimal MoS2/NiS2 nanosheets show the enhanced electrocatalytic performances as bifunctional electrocatalysts for overall water splitting. This study may open up a new route for rationally constructing heterogeneous interfaces to maximize their electrochemical performances, which may help to accelerate the development of nonprecious electrocatalysts for overall water splitting.", "author_names": [ "Jinghuang Lin", "Pengcheng Wang", "Haohan Wang", "Chun Li", "Xiaoqing Si", "Junlei Qi", "Jian Cao", "Zhengxiang Zhong", "Weidong Fei", "Ji-cai Feng" ], "corpus_id": 182920464, "doc_id": "182920464", "n_citations": 182, "n_key_citations": 1, "score": 0, "title": "Defect Rich Heterogeneous MoS2/NiS2 Nanosheets Electrocatalysts for Efficient Overall Water Splitting", "venue": "Advanced science", "year": 2019 }, { "abstract": "Abstract Although graphitic carbon nitride (g C3N4) is an attractive photocatalyst for solar H2 generation, the preparation of g C3N4 nanosheets via a \"green\" and simple method as well as the construction of highly efficient g C3N4 based photocatalysts are still challenges. In this study, g C3N4 nanosheets prepared by a simple probe sonication assisted liquid exfoliation method were used to construct 2D 2D MoS2/g C3N4 photocatalyst for photocatalytic H2 production. The 2D 2D MoS2/g C3N4 photocatalyst containing 0.75% MoS2 showed the highest H2 evolution rate of 1155 mmol*h 1*g 1 with an apparent quantum yield of 6.8% at 420 nm monochromatic light, which is much higher than that of the optimized 0D 2D Pt/g C3N4 photocatalyst. The high photocatalytic H2 production activity of 2D 2D MoS2/g C3N4 photocatalyst can be attributed to the large surface area and the formed 2D interfaces between MoS2 and g C3N4 nanosheets. As demonstrated by photoluminescence quenching and time resolved fluorescence decay studies, the 2D interfaces can accelerate the photoinduced charge transfer, resulting in the high photocatalytic H2 production performance. This study provides a new strategy in developing highly efficient g C3N4 based photocatalysts for H2 production via using 2D nanojunction as a bridge to promote the photoinduced charge separation and transfer.", "author_names": [ "Yongjun Yuan", "Zhi-Kai Shen", "Shiting Wu", "Yibing Su", "Lang Pei", "Zhen-guo Ji", "Mingye Ding", "Wangfeng Bai", "Yifan Chen", "Zhen-Tao Yu", "Zhi-gang Zou" ], "corpus_id": 104317370, "doc_id": "104317370", "n_citations": 254, "n_key_citations": 0, "score": 0, "title": "Liquid exfoliation of g C3N4 nanosheets to construct 2D 2D MoS2/g C3N4 photocatalyst for enhanced photocatalytic H2 production activity", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "A novel approach to effectively suppress the \"polysulfide shuttle\" in Li S batteries is presented by designing a freestanding, three dimensional graphene/1T MoS2 (3DG/TM) heterostructure with highly efficient electrocatalysis properties for lithium polysulfides (LiPSs) The 3DG/TM heterostructure is constructed by few layered graphene nanosheets sandwiched by hydrophilic, metallic, few layered 1T MoS2 nanosheets with abundant active sites. The porous 3D structure and the hydrophilic feature of 1T MoS2 are beneficial for electrolyte penetration and Li ion transfer, and the high conductivities of both graphene and the 1T MoS2 nanosheets facilitate electron transfer. These merits lead to a high electrocatalytic efficiency for LiPSs due to excellent ion/electron transfer and the presence of sufficient electrocatalytic active sites. Therefore, the cells with 3DG/TM exhibit outstanding electrochemical performance, with a high reversible discharge capacity of 1181 mA h g 1 and a capacity retention of 96.3% after 200 cycles. The electrocatalysis mechanism of LiPSs is further experimentally and theoretically revealed, which provides new insights and opportunities to develop advanced Li S batteries with highly efficient electrocatalysts for LiPS conversion.", "author_names": [ "Jiarui He", "Gregor Hartmann", "Myungsuk Lee", "Gyeong S Hwang", "Yuanfu Chen", "Arumugam Manthiram" ], "corpus_id": 106216327, "doc_id": "106216327", "n_citations": 238, "n_key_citations": 0, "score": 0, "title": "Freestanding 1T MoS2/graphene heterostructures as a highly efficient electrocatalyst for lithium polysulfides in Li S batteries", "venue": "", "year": 2019 }, { "abstract": "Abstract Exposing the highly active facets and hybridizing the photocatalyst with appropriate cocatalysts with right placement have been regarded as a powerful approach to high performance photocatalysts. Herein, TiO2 nanosheets (NSs) are in situ grown on highly conductive Ti3C2 MXene and then MoS2 NSs are deposited on the (101) facets of TiO2 NSs with mainly exposed high active (001) facets through a two step hydrothermal method. And a unique 2D 2D 2D structure of Ti3C2@TiO2@MoS2 composite is achieved. With an optimized MoS2 loading amounts (15 wt% the Ti3C2@TiO2@MoS2 composite shows a remarkable enhancement in the photocatalytic H2 evolution reaction compared with Ti3C2@TiO2 composite and TiO2 NS. It also shows good stability under the reaction condition. This arises from: (i) the in situ growth of TiO2 NSs construct strong interfacial contact with excellent electronic conductivity of Ti3C2, which facilitates the separation of carriers; (ii) the coexposed (101) and (001) facets can form a surface heterojunction within single TiO2 NS, which is beneficial for the transfer and separation of charge carriers; and (iii) the MoS2 NSs are deposited on the electrons rich (101) facets of TiO2 NSs, which not only effectively reduces the charge carriers recombination rate by capturing photoelectrons, but also makes TiO2 NSs expose more highly active (001) facets to afford high efficiency photogeneration of electron hole pairs.", "author_names": [ "Yujie Li", "Zhaohua Yin", "Guanrui Ji", "Zhang Liang", "Yanjun Xue", "Yichen Guo", "Jian Tian", "Xinzhen Wang", "Hongzhi Cui" ], "corpus_id": 104409167, "doc_id": "104409167", "n_citations": 169, "n_key_citations": 0, "score": 0, "title": "2D/2D/2D heterojunction of Ti3C2 MXene/MoS2 nanosheets/TiO2 nanosheets with exposed (001) facets toward enhanced photocatalytic hydrogen production activity", "venue": "Applied Catalysis B: Environmental", "year": 2019 }, { "abstract": "Low dimensional materials have been examined as electrocatalysts for the hydrogen evolution reaction (HER) Among them, two dimensional transition metal dichalcogenides (2D TMDs) such as MoS2 have been identified as potential candidates. However, the performance of TMDs toward HER in both acidic and basic media remains inferior to that of noble metals such as Pt and its alloys. This calls for investigating the influence of controlled defect engineering of 2D TMDs on their performance toward hydrogen production. Here, we explored the HER activity from defective multilayered MoS2 over a large range of surface S vacancy concentrations up to 90% Amorphous MoS2 and 2H MoS2 with ultrarich S vacancies demonstrated the highest HER performance in acid and basic electrolytes, respectively. We also report that the HER performance from multilayered MoS2 can be divided into two domains corresponding to \"point defects\" at low concentrations of surface S vacancies (Stage 1) and large regions of undercoordinated Mo atoms for high concentrations of surface S vacancies (Stage 2) The highest performance is obtained for Stage 2 in the presence of undercoordinated Mo atoms with a TOF of ~2 s 1 at an overpotential of 160 mV in 0.1 M KOH which compares favorably to the best results in the literature. Overall, our work provides deeper insight on the HER mechanism from defected MoS2 and provides guidance for the development of defect engineered TMD based electrocatalysts.", "author_names": [ "Lei Li", "Zhao-Xian Qin", "Lucie Ries", "Song Hong", "Thierry Michel", "Jieun Yang", "Chrystelle Salameh", "Mikhael Bechelany", "Philippe Miele", "Daniel Kaplan", "Manish Chhowalla", "Damien Voiry" ], "corpus_id": 206723788, "doc_id": "206723788", "n_citations": 160, "n_key_citations": 0, "score": 0, "title": "Role of Sulfur Vacancies and Undercoordinated Mo Regions in MoS2 Nanosheets toward the Evolution of Hydrogen.", "venue": "ACS nano", "year": 2019 }, { "abstract": "We show that inversion symmetry breaking together with spin orbit coupling leads to coupled spin and valley physics in monolayers of MoS2 and other group VI dichalcogenides, making possible controls of spin and valley in these 2D materials. The spin valley coupling at the valence band edges suppresses spin and valley relaxation, as flip of each index alone is forbidden by the valley contrasting spin splitting. Valley Hall and spin Hall effects coexist in both electron doped and hole doped systems. Optical interband transitions have frequency dependent polarization selection rules which allow selective photoexcitation of carriers with various combination of valley and spin indices. Photoinduced spin Hall and valley Hall effects can generate long lived spin and valley accumulations on sample boundaries. The physics discussed here provides a route towards the integration of valleytronics and spintronics in multivalley materials with strong spin orbit coupling and inversion symmetry breaking.", "author_names": [ "Di Xiao", "Gui-Bin Liu", "Wanxiang Feng", "Xiaodong Xu", "Wang Yao" ], "corpus_id": 13621082, "doc_id": "13621082", "n_citations": 2648, "n_key_citations": 58, "score": 0, "title": "Coupled spin and valley physics in monolayers of MoS2 and other group VI dichalcogenides.", "venue": "Physical review letters", "year": 2012 }, { "abstract": "The identification of the active sites in heterogeneous catalysis requires a combination of surface sensitive methods and reactivity studies. We determined the active site for hydrogen evolution, a reaction catalyzed by precious metals, on nanoparticulate molybdenum disulfide (MoS2) by atomically resolving the surface of this catalyst before measuring electrochemical activity in solution. By preparing MoS2 nanoparticles of different sizes, we systematically varied the distribution of surface sites on MoS2 nanoparticles on Au(111) which we quantified with scanning tunneling microscopy. Electrocatalytic activity measurements for hydrogen evolution correlate linearly with the number of edge sites on the MoS2 catalyst.", "author_names": [ "Thomas Francisco Jaramillo", "Kristina Pilt Jorgensen", "Jacob Bonde", "Jane Hvolbaek Nielsen", "Sebastian Horch", "Ib Chorkendorff" ], "corpus_id": 12862855, "doc_id": "12862855", "n_citations": 3816, "n_key_citations": 22, "score": 0, "title": "Identification of Active Edge Sites for Electrochemical H2 Evolution from MoS2 Nanocatalysts", "venue": "Science", "year": 2007 } ]

[ { "abstract": "The CH3NH3PbI3 based photodetectors were fabricated with a coplanar metal semiconductor metal (MSM) IDT patterned Au electrode configuration. The MSM structured perovskite based photodetectors exhibited a higher Ion/Ioff of about 3.77 x 102, and a response of 6.66 mA/W. Additionally, the photodetectors worked best under red illumination, and the rise and decay times were estimated to shorter than 0.04 s and 0.05 s. Especially, the durability and stability of these photodetectors were excellent, which can be exposed to the red light illumination over 1000 s. There were still stable photocurrent signal after 90 days. It indicated that the device possessed a longer durability and had a lifetime of exceeding 90 days. These outstanding performances could be potentially applicable for practical applications.", "author_names": [ "Fuqiang Guo", "Xiaohang Li", "Baohua Zhang", "Lili Zhang", "Haineng Bai", "Zheng Guo Zhang", "Qian Yang", "Yang Tan", "Xuebo Liu", "Yihua Song", "Yineng Huang" ], "corpus_id": 203928798, "doc_id": "203928798", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Durable and stable UV Vis perovskite photodetectors based on CH3NH3PbI3 crystals synthesized via a solvothermal method", "venue": "Journal of Materials Science: Materials in Electronics", "year": 2019 }, { "abstract": "Low dimensional lead free organic inorganic hybrid perovskites have gained increasing attention as having low toxicity, ease of processing, and good optoelectronic properties. Seeking for lead free and narrow band gap organic inorganic hybrid perovskites are of great importance for the development and application of photoelectric materials. Here, we reported a Sb based organic inorganic hybrid perovskite (MV)[SbI3Cl2] which has one dimensional inorganic frameworks of the I sharing double octahedra. (MV)[SbI3Cl2] shows a narrow direct band gap of 1.5 eV, and displays obvious photoresponse for the 532 nm light with rapid response speed of trise 0.69 s, tdecay 0.28 s. With an illumination power of 5 mW and a 50 V bias, the responsivities (R) and external quantum efficiency (EQE) for (MV)[SbI3Cl2] photodetector under 532 nm laser are 29.75 mA/W and 6.69% respectively. This Sb based halide double perovskite material will provide an alternative material for photodetector devices.", "author_names": [ "Yun Lei", "Shouyu Wang", "Jie Xing", "Hanqi Xu", "Jing Han", "Weifang Liu" ], "corpus_id": 214644033, "doc_id": "214644033", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "High Performance UV Vis Photodetectors Based on a Lead Free Hybrid Perovskite Crystal (MV)[SbI3Cl2]", "venue": "Inorganic chemistry", "year": 2020 }, { "abstract": "Organolead halide perovskite has recently emerged as a star material for various photoelectronic devices owing to its excellent optical and electronic properties. However, it is challenging to deve.", "author_names": [ "Fobao Huang", "Ying-quan Peng", "Guohan Liu" ], "corpus_id": 146097017, "doc_id": "146097017", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Toward Ultrahigh Sensitivity and UV Vis NIR Broadband Response of Organolead Halide Perovskite/Tin Phthalocyanine Heterostructured Photodetectors", "venue": "The Journal of Physical Chemistry C", "year": 2019 }, { "abstract": "A lateral photodetector based on the bilayer composite film of a perovskite and a conjugated polymer is reported. It exhibits significantly enhanced responsivity in the UV vis region and sensitive photoresponse in the near IR (NIR) region at a low applied voltage. This broadband photodetector also shows excellent mechanical flexibility and improved environmental stability.", "author_names": [ "Shan Chen", "Changjiu Teng", "Miao Zhang", "Yingru Li", "Dan Xie", "Gaoquan Shi" ], "corpus_id": 12906186, "doc_id": "12906186", "n_citations": 235, "n_key_citations": 1, "score": 0, "title": "A Flexible UV Vis NIR Photodetector based on a Perovskite/Conjugated Polymer Composite.", "venue": "Advanced materials", "year": 2016 }, { "abstract": "Methylammonium lead halide perovskites have been reported to be promising candidates for high performance photodetectors. However, self powered broadband ultraviolet visible near infrared (UV Vis NIR) photodetection with high responsivity is difficult to achieve in these materials. Here, we demonstrate, for the first time, a novel trilayer hybrid photodetector made by combining an n type Si wafer, TiO2 interlayer and perovskite film. By precisely controlling the thickness of the TiO2 layer, enhanced separation and reduced recombination of carriers at the Si perovskite interface are obtained. As a result, perovskite film, when combined with a low bandgap Si, extends the wavelength range of photo response to 1,150 nm, along with improved on/off ratio, responsivity, and specific detectivity, when compared to pristine perovskite. Results obtained in this work are comparable or even better than those reported for perovskite based UV Vis NIR photodetectors. In particular, the hybrid photodetectors can operate in a self powered mode. The mechanism of enhancement has been explored and it is found that the increased separation and reduced recombination of photogenerated carriers at the junction interface leads to the improved performance.", "author_names": [ "Fengren Cao", "Qingliang Liao", "Kaimo Deng", "Liang Chen", "Liang Li", "Yue Kan Zhang" ], "corpus_id": 139622396, "doc_id": "139622396", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Novel perovskite/TiO2/Si trilayer heterojunctions for high performance self powered ultraviolet visible near infrared (UV Vis NIR) photodetectors", "venue": "Nano Research", "year": 2018 }, { "abstract": "DOI: 10.1002/adom.201800324 yields with narrow emission bandwidth, size tunable optical properties, strong optical absorption, and more impor tantly, good environmental stabilities.[1 3] They have also been applied to develop high performance solar cells, light emit ting diodes (LEDs) and lasers.[4 7] Several recent works[8 11] have pioneered the appli cation of IPQDs in photodetectors with vertical (photodiode) and lateral (photo conductor and photo transistor) device structures. However, most of them show low responsivity up to 0.64 A W 1. The reported responsivities of IPQD devices are limited by poor carrier mobility due to the choice of interparticle ligand mate rials and high density of defect states.[12] To develop highresponsivity photodetec tors, it is vital to increase carrier diffu sion length. One approach is to decrease the density of defects and increase car rier mobility, which has been a prevalent research topic.[13] However, an alternative method to increase responsivity is to separate electrons and holes into different paths and suppress radiative recombination with the aid of layered heterojunction (LHJ)[14] This strategy should facili tate the extractions of generated carriers and thus increase the photocurrent. There are some recent works adopting this strategy and thus improving the responsivity. Zhou et al.[15] fab ricated CsPbBr3 QD/TiO2 compositebased photodetectors and obtained a 44fold responsivity enhancement compared to pris tine CsPbBr3 QD photodetectors over the detection range from 350 to 550 nm. Chen et al.[16] reported hybrid phototransistors based on CsPbBr3 QD/DTT heterojunctions and achieved the responsivity up to 1.7 x 104 A W 1, however, the detection range only reached up to green wavelength on the long side. Kwak et al.[17] fabricated CsPbBr3 xIx QD/graphene bilayer photode tectors, exhibiting a very high responsivity (108 A W 1) but a decent onoff ratio, the detection wavelength range is limited up to 650 nm. These findings encourage us to use a LHJ film in the photodetector to enhance the performance. Although such IPQDbased hybrid photodetectors exhibit high respon sivity, the detection wavelength regions are still restricted to ultravioletvisible (UV vis) range and cannot reach near infrared (NIR) region. Furthermore, among all reported IPQD detectors, few of them are based on CsPbI3 QDs and targeted All inorganic perovskite quantum dots (IPQDs) are a promising material for use in various optoelectronic devices due to their excellent optoelectronic properties and high environmental stability. Here, a high performance phototransistor based on a layered heterojunction composed of CsPbI3 QDs and a narrow bandgap conjugated polymer DPP DTT is reported, which shows a high responsivity of 110 A W 1, a specific detectivity of 2.9 x 1013 Jones and a light to dark current ratio up to 6 x 103. The heterojunction phototransistor exhibits unipolar p type and gate bias modulated behaviors. In addition, the device exhibits a broad spectral detection range from ultraviolet to near infrared. The high sensitivity of the device is attributed to the layered heterojunction and the gate bias modulation property. The work overcomes the existing limitations in sensitivity of IPQD photodetectors due to the poor charge transport between QDs. The convenient solution processed fabrication and excellent device performance especially suggest the IPQD/narrow bandgap conjugate polymer heterojunction as a promising structure for potential applications of ultrasensitive broadband photodetectors compatible with a wide variety of substrates.", "author_names": [ "Chen Zou", "Yuyin Xi", "Chun-Ying Huang", "Ethan G Keeler", "Tianyu Feng", "Shihao Zhu", "Lilo D Pozzo", "Lih Y Lin" ], "corpus_id": 51915490, "doc_id": "51915490", "n_citations": 24, "n_key_citations": 0, "score": 0, "title": "A Highly Sensitive UV vis NIR All Inorganic Perovskite Quantum Dot Phototransistor Based on a Layered Heterojunction", "venue": "", "year": 2018 }, { "abstract": "Hybrid organic inorganic perovskites have been demonstrated as promising candidates for broadband responsive photodetectors. It is critical to develop perovskite based photodetectors with excellent photodetection capability and facile fabrication processes for practical application. Herein, we designed and fabricated, for the first time, a hybrid photodetector consisting of electrospun ZnO nanofibers and perovskites. Compared to pristine ZnO or perovskite, the hybrid photodetector showed increased on off ratio, faster response speed, and higher responsivity and detectivity. The performance of the hybrid devices was significantly enhanced by using quasi aligned ZnO nanofiber arrays instead of disordered nanofibers, which provide efficient charge transfer between the perovskite and ZnO, shorter transmission paths, and reduced carrier loss at cross junctions of nanofibers. Our results provide a new and promising route to integrate inorganic functional materials with perovskite for high performance and low cost photodetectors.", "author_names": [ "Fengren Cao", "Wei Tian", "Bangkai Gu", "Yulong Ma", "Hao Lu", "Liang Li" ], "corpus_id": 136290366, "doc_id": "136290366", "n_citations": 53, "n_key_citations": 0, "score": 0, "title": "High performance UV vis photodetectors based on electrospun ZnO nanofiber solution processed perovskite hybrid structures", "venue": "Nano Research", "year": 2017 }, { "abstract": "", "author_names": [ "Feng-xia Liang", "Lin Liang", "Xing-yuan Zhao", "Lin-Bao Luo", "Yu-Hung Liu", "Xiao-Wei Tong", "Zhi-Xiang Zhang", "J C Huang" ], "corpus_id": 104452710, "doc_id": "104452710", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "A Sensitive Broadband (UV vis NIR) Perovskite Photodetector Using Topological Insulator as Electrodes", "venue": "", "year": 2018 }, { "abstract": "We report a high performance phototransistor based on a layered heterojunction composed of all inorganic perovskite quantum dots (IPQDs) and a narrow bandgap conjugated polymer DPP DTT. The device exhibits stable and excellent optoelectronic properties with broadband photodetection range.", "author_names": [ "Chen Zou", "Yuyin Xi", "Lilo D Pozzo", "Lih Y Lin" ], "corpus_id": 51975773, "doc_id": "51975773", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Highly Sensitive UV Vis NIR Inorganic Perovskite Quantum Dot Phototransistors Based on Layered Heterojunctions", "venue": "2018 Conference on Lasers and Electro Optics (CLEO)", "year": 2018 }, { "abstract": "We present an investigation of the ultrafast charge carrier dynamics for the one third metal deficient lead free perovskite (CH3NH3)3Bi2I9 on mesoporous TiO2. Excitation of the perovskite at 400 or 505 nm leads to characteristic second derivative type spectral features in the transient absorption spectra, suggesting substantial contributions of bound excitons, in contrast to the widely used lead based perovskites. The immediate appearance of broad NIR absorption is assigned to TiO2 conduction band electrons formed by instantaneous dissociation of a subpopulation of excitons at the perovskite/TiO2 interface. Excitation with excess energy above the perovskite's band gap opens up an additional fast (70 fs) exciton dissociation channel with about 26% amplitude. Antisolvent assisted synthesis of (CH3NH3)3Bi2I9 reduces the crystallite size to about 500 nm but has only a minor effect on the carrier dynamics. The results suggest that photovoltaic applications of this material will likely require bulk heterojuncti.", "author_names": [ "Mirko Scholz", "Oliver Flender", "Kawon Oum", "Thomas Lenzer" ], "corpus_id": 98927647, "doc_id": "98927647", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Pronounced Exciton Dynamics in the Vacancy Ordered Bismuth Halide Perovskite (CH3NH3)3Bi2I9 Observed by Ultrafast UV vis NIR Transient Absorption Spectroscopy", "venue": "", "year": 2017 } ]

[ { "abstract": "This thesis presents the first experimental results of a scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) investigation of rubrene at the supramolecular, molecular and submolecular level. Based on its semiconducting and fluorescent properties, this molecule is of particular interest in view of the emerging fields of molecular electronics and optoelectronics which could one day replace the conventional technology relying on semiconductors such as silicon and gallium arsenide. The goal is the substitution of these inorganic materials by cheap and flexible layers of semiconducting organic molecules for a new class of diodes and transistors, as well as the realization of electronic switches based on individual molecules. One fundamental approach is to take advantage of the molecular self assembly behavior which results in the creation of well ordered supramolecular structures. The investigations of the self assembly of rubrene adsorbed on metal surfaces (Au(111) Au(100) Ag(111) and Ag(100) which were carried out within the framework of this thesis, show a surprising diversity of supramolecular structures. Amongst other shapes, the molecules organize themselves into geometries of perfect hexagonal and pentagonal symmetry and create multifaceted patterns on the surface. A fascinating peculiarity consists in the spontaneous construction of nested structures which are built up by a hierarchical self assembly of individual molecules into pentagonal supermolecules which form in a second step perfect supramolecular decagons. The geometric shape of rubrene is characterized by a structural asymmetry leading to the existence of two mirror imaged versions of the molecule which are not superimposable to each other, such as for instance our left and right hand or the helical DNA. The aspect of chirality is crucial for basic processes in living systems and calls for a fundamental understanding of the interaction mechanisms occurring between chiral molecules. The experiments on rubrene reveal that the intermolecular bonding differentiates between the two chiral types of the molecule (chiral recognition) yielding the self organization into homochiral structures. These assemblies exhibit a geometry which is again chiral, demonstrating a propagation of chirality throughout the three stages of the supramolecular hierarchy. The semiconducting behavior of rubrene is furthermore probed by STS measurements detecting the energetic positions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) The experimental data uncover that different adsorption conformations exhibit characteristic HOMO energies and reveal adsorption conformations of rubrene which preserve the intrinsic electronic structure of the free molecule. Furthermore, a switching of the molecular conformation and the electronic structure of one rubrene conformer is induced with the STM.", "author_names": [ "M C Blum" ], "corpus_id": 91622241, "doc_id": "91622241", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Supramolecular assembly, chirality, and electronic properties of rubrene studied by STM and STS", "venue": "", "year": 2006 }, { "abstract": "The self assembly of functional molecules into uniform nanostructures with innovational properties has attracted extensive research interest. In the present work, the assembly structures and electronic properties of a novel type of truxene derivative, e.g. truxene porphyrin derivatives, were studied, for the first time, on a highly oriented pyrolytic graphite (HOPG) surface. Scanning tunneling microscopy (STM) images revealed that the truxene porphyrin compounds could be parallelly arranged into long ranged lamellar patterns. Density functional theory (DFT) calculations helped explain the assembly mechanisms further. Besides, order distribution of the smaller compound 1T1P in the 1,3,5 tris(10 carboxydecyloxy) benzene (TCDB) host network was achieved, which is a reflection of the dimensional effect in the host guest assembly. Furthermore, together with theoretical analyses, scanning tunneling spectroscopy (STS) measurements were conducted to investigate the electronic properties of truxene porphyrin compounds. Results showed that the metalation of the porphyrin units could have a significant effect on the band gap and the position of the gap center. The study enhances our understanding of the assembly mechanism of truxene derivatives at the molecular level and paves the way towards fabricating truxene based functional nanodevices.", "author_names": [ "Haijun Xu", "Hongyu Shi", "Yuhong Liu", "Jian Song", "Xinchun Lu", "Claude P Gros", "Ke Deng", "Qingdao Zeng" ], "corpus_id": 149675262, "doc_id": "149675262", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Assembly structures and electronic properties of truxene porphyrin compounds studied by STM/STS.", "venue": "Dalton transactions", "year": 2019 }, { "abstract": "The design, synthesis and self assembly of supramolecular nanostructures with attractive physical and chemical characteristics have drawn much attention during recent decades, mainly due to their applications in a vast number of fields, including chemistry, physics and engineering. The development of novel electronic devices, smart surfaces and pre programmed architectures, among others, have been envisaged. The present thesis concerns to the self assembly and the electronic properties of p expanded macrocycles into ordered supramolecular architectures, investigated by means of scanning tunneling microscopy (STM) and spectroscopy (STS) at the solidliquid interface between organic solutions and highly oriented pyrolytic graphite (HOPG) Particularly, self assembled monolayers of macrocycles of four p expanded macrocyclic oligothiophene 8 mers were investigated. One of the macrocycles, cyclo[8](3,4dibutyl 2,5 thienylene ethynylene) 8T8A, contains eight ethynylenes, while two other macrocycles are the photoisomers Z,Z 8T6A and E,E 8T6A, where two of the ethynylenes in opposite positions of the ring are replaced by cisand trans ethylenes, respectively. An additional macrocycle, E 8T7A, corresponds to seven ethynylenes and one trans ethylene groups. STM height images reveal hexagonally ordered 2D networks with small differences in the unit cells. Current voltage (I V) characteristics confirm the expected donor like character of the macrocycles with very similar LUMO positions for all macrocycles, and HOMO positions independent of the amount of ethynylene and ethylene groups. Cyclic STS measurements indicate that Z,Z 8T6A switches to its isomer E,E 8T6A after formation of a most stable cationic species, consistent with voltammetry and chemical oxidation experiments. This result represents the first reported electrochemi", "author_names": [ "C E Gonzalez", "J A David" ], "corpus_id": 139602710, "doc_id": "139602710", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Self Assembly and Electronic Properties of p expanded Macrocycles", "venue": "", "year": 2018 }, { "abstract": "Porphyrins and phthalocyanines are currently a prevalent topic with great potential due to their abundant photonic/electronic properties. The study of porphyrin or phthalocyanine supramolecular arc.", "author_names": [ "Yuxin Qian", "Bo Liu", "Wu-biao Duan", "Qingdao Zeng" ], "corpus_id": 103462031, "doc_id": "103462031", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Assemblies of porphyrin and phthalocyanine derivatives studied by STM", "venue": "", "year": 2018 }, { "abstract": "In this paper we report the study of the change in electrical properties of zigzag carbon nanotubes (10, 0) under uniaxial compressive and tensile deformation using Density Functional Theory (DFT) calculation. There is an energy gap of 0.972 eV between occupied and unoccupied region in the optimized structure calculation. We found that the band gap of the semi conducting zigzag (10, 0) CNTs decreases as the strain increases for both compressive and tensile deformation. Different profiles of charge density appear for tensile and compressive deformations. The charge density of compressed state is more localized in the z direction of C C bonds. Meanwhile, charge density of elongated state is localized in the diagonal C C bonds direction. At the large tensile strain, the C C bonds break at the z direction C C bonds. ICOHP analysis shows that the bond strength of CNT drastically decreases under tensile deformation. Keyword: band gap, carbon nanotubes, charge density, density functional theory. INTRODUCTION The development of science and technology has evolved into the era of nanotechnology. Among the many nanostructured materials, carbon nanotubes (CNTs) have attracted considerable attention. Compared to other nanoscale materials, single walled carbon nanotubes (SWCNT) possess particularly outstanding physical and electronic properties. Due to the extremely small size of CNTs, the evaluation of its mechanical properties, such as elastic modulus and tensile/compressive strength presents significant challenges to researchers who work in nanomechanics. Electronic states of single walled carbon nanotubes (SWNCT) such as Density of states (DOS) and band gap, could be correlated with their finite mechanical deformation behavior. The study of this effect is important in view of the ability to manipulate individual nanotubes for many applications. Recently, Obitayo and Liu [1] have been developed carbon nanotubes as strain sensor its I V characteristic behavior due to axial change has been explored. In that work, they conclude that for carbon nanotube based strain sensing applications, the small gap semiconducting single walled carbon nanotubes offer the greatest sensitivity. Even though many research have studied the change of electronics properties of nanotubes under uniaxial deformation [1 3] the theoretical approach in investigating the band gap changes has not been revealed up completely. Because of the nanoscale size of CNTs, the experiments to measure the properties of individual CNT are quite difficult. Therefore, the ab initio calculations have been regarded as a powerful tool to study properties of CNTs. In the present report, we calculate the atomic and electronic structure changes of the CNTs under tensile and compressive deformation by using Density Functional Theory (DFT) calculation. We focused on band gap and bond strength changes due to mechanical uniaxial tensile and compressive deformation. COMPUTATIONAL DETAILS We carried out the first principles calculations on the density functional theory (DFT) level, using the \"Vienna ab initio simulation package\" [4 6] The calculation was performed in QC Cluster at Department of Physics ITB. Generalized gradient approximation (GGA) with the Perdew Burke Ernzerhof (PBE) [7] functional is selected in our calculations. A plane wave basis set was employed within the framework of the projector augmented wave method.[8, 9] K points (1 x 1 x 17 Monkhorst Pack grid) were used in this simulations. One k point in the two perpendicular directions was enough because the distance between the individual tubes was chosen very large (16 A) so that the interaction between them was negligible. We selected zigzag type semiconducting CNTs (10,0) The axial direction (z) of these CNTs was selected as the tensile direction. Before we started the tensile test, the z dimension of the supercells and the initial atomic configuration were completely relaxed. These relaxed z dimensions of the supercells were used as a reference when calculating the applied strains in the following discussion. The electronic properties of zigzag CNT can be obtained by using electronic density of states calculations. The optimized structure data from SCF calculations can be used to reduce calculation time and neglect structural optimization process. Generally, the mesh K point sampling for DOS calculation is higher than that of SCF calculations for calculation's accuracy. To know further the nature of bonding of elongated /compressed CNT, we projected plane waves to local orbital basis functions to extract the crystal orbital Hamilton population COHP) [10] The integration of COHP for all energies up to EF gives integrated COHP (ICOHP) to render a quasiquantitative interpretation [11] of the net bonding characteristics. This ICOHP were calculated by using the program Local Orbital Basis Suite towards Electronic Structure Reconstruction (LOBSTER) [11 13] VOL. 13, NO. 7, APRIL 2018 ISSN 1819 6608 ARPN Journal of Engineering and Applied Sciences (c)2006 2018 Asian Research Publishing Network (ARPN) All rights reserved. www.arpnjournals.com 2391 RESULT AND DISCUSSIONS Change in density of states during deformation From the DFT calculation using VASP software, we got the optimized structure of zigzag CNTs (10, 0) The zigzag edge (10, 0) CNT has two different carboncarbon (C C) bond length, 1.42 A and 1.43 A. The diameter of this optimize structure is 7.89 A. Our optimized CNTs model was then be compressed and elongated in uniaxial direction (z direction) There is an energy gap of 0.972 eV between occupied and unoccupied region, which indicates that the system is semiconducting. This result is in agreement with other first principle calculation studies which have been published [14 16] This result is also supported by experimental and theoretical approach results from other studies. According to the chiral vector information, the pristine zigzag edge (10,0) CNT is semiconducting material [17] This result is also in a good agreement with experimental result by using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) [17, 18] The electronic structures of CNTs with various structures under axial strain are evaluated by DFT calculations. To analyze the band gap dependency on uniaxial deformation, we observe the DOS of the deform structure of zigzag edge CNT (10, 0) The band gap versus strain curves for a zigzag (10, 0) CNTs during the tensile tests are shown in Figure 1. Negative value means that the final deformed structure is shorter than the optimize bulk structure (compressed) Vice versa, the positive value shows that the final deformed structure is longer than the optimize bulk structure (elongated) Previous work on semiconducting CNTs shows the same result with this work. The band gap for the semiconducting zigzag (10, 0) CNTs displays some variation upon deformation, but most of it decreases as the strain increases [16] This calculation result also shows that there is semiconductor metallic transition of the CNTs. The (10,0) zigzag tube has zero band gap like graphene at the strain of 8.3% which means that it possesses metallic electronic properties at this state and returns to the semiconducting state as the strain increases. Since another work suggests that the small gap semiconducting single walled carbon nanotubes offer the greatest sensitivity for the sensor application, we can conclude that CNT (10, 0) can be a good candidate for CNT based strain sensors. Figure 1. The band gap versus strain for semi conducting zigzag (10,0) CNTs. Deformation electron density VOL. 13, NO. 7, APRIL 2018 ISSN 1819 6608 ARPN Journal of Engineering and Applied Sciences (c)2006 2018 Asian Research Publishing Network (ARPN) All rights reserved. www.arpnjournals.com 2392 Figure 2. (a) Focused area for charge density analyzing; Charge density of the (10,0) zigzag CNT under: (b) 2% (c) 10% compressive and (e) 1% (f) 10% tensile strain. Figure 2 shows change in the charge density of the (10,0) zigzag CNT under compressive and tensile strain. We analyze the two dimensional charge density slice of the semiconducting zigzag (10, 0) CNTs focusing on the red circle area shown in the Figure 2(a) Charge density of the CNT before imposed by uniform stretching or compressed of the initial atomic configuration in the z direction is shown in Figure 2(b) Charge density during the compressive deformation is shown in Figure 2(c) and (d) it can be seen that the charge density becomes more localized in the z direction C C bonds and the angle of the hexagonal carbon formation decreases. The amount of localized charge density also increases as the compressive strain increase. The different profile appears during tensile deformation. The charge density, as shown in Figure 2(e) and (f) decreases as the tensile strain increase. The Charge density is localized in the diagonal C C bonds. At large strain, i.e. 7% for tensile and 5% for compression, the C C bonds break at the z direction C C bonds. This indicates that for more than 7% tensile and 5% compressive strain, CNT starts to break and no longer efficient to be used as a sensor. Because when some C C bonds are broken, the CNT is in plastic region, so when it is strained, it will not return to its original shape. For the strain sensor application, CNT should be able to return to its original shape, it means that the CNT should be in the elastic region. From our charge density analysis, the elastic region of CNT (10, 0) might be below 7% tensile and 5% compressive strain. From this figure also we can conclude that the bond strength of the CNT under compressive deformation is higher compared to that of tensile deformation. It is indicated by the higher value of the electron density in compressive deformation compared to tensile deformation at the same strain. To study further about this bond strength, we perform the ICOHP calculation. Bond strength Integratin", "author_names": [ "Irfan Dwi Aditya", "" ], "corpus_id": 189859481, "doc_id": "189859481", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "ELECTRONIC PROPERTIES OF SEMICONDUCTING ZIGZAG 10 0 CARBON NANOTUBES DUE TO UNIAXIAL STRAIN", "venue": "", "year": 2018 }, { "abstract": "At present, organic molecules are among the best candidate \"building blocks\" for the construction of self assembling nanoscale devices based on metal substrates. Control of the formation of specific patterns in the submonolayer regime is usually achieved by appropriate choice and/or functionalization of the adsorbates. The effect of this intervention, though, is limited by the typically short range character of the bonding. We present here a theoretical study on the system rubrene/gold to show that substrate induced molecular charging can instead determine the assembly on larger scales. DFT calculations and electrostatic considerations are used to discuss the charge transfer at the metal/organic interface. This allows rationalization of previous puzzling experimental results and, in particular, of the unusual molecular gap broadening upon adsorption observed in STS spectra. The self assembly process is further studied by means of classical molecular dynamics simulations. The charged adsorbates are modeled as mutually repulsive standing dipoles, with van der Waals interactions intervening at short distances. The striking resemblance between the experimental STM images and the results of our MD simulations shows that this simple model is able to capture the key effects driving the assembly in this system. The competition between long range repulsive interactions and short range attractive forces leads to characteristic and easily recognizable 1D patterns. We suggest that experimental evidence of the presence of similar patterns in other metal/organic systems can provide crucial information on the electronic level alignment at the interface, that is, on the occurrence of charge transfer processes between metal and organic adsorbates.", "author_names": [ "Giulia Tomba", "Massimiliano Stengel", "Wolf-Dieter Schneider", "Alfonso Baldereschi", "Alessandro De Vita" ], "corpus_id": 19352779, "doc_id": "19352779", "n_citations": 51, "n_key_citations": 2, "score": 0, "title": "Supramolecular self assembly driven by electrostatic repulsion: The 1D aggregation of rubrene pentagons on Au111.", "venue": "ACS nano", "year": 2010 }, { "abstract": "Highly ordered assemblies prepared from tetra (4 sulfonatophenyl) phthalocyanine (TSPc) by employing very acidic aqueous solutions were deposited onto Au(111) substrates and studied in UHV using X ray photoelectron spectroscopy (XPS) scanning tunneling microscopy (STM) and orbital mediated tunneling spectroscopy (OMTS) XPS of the TSPc aggregates shows that the ratio of protonated to unprotonated nitrogens does not change with decreasing solution pH. STM images of TSPc deposited from pH <1 solutions reveal ordered branched web like assemblies hundreds of nanometers in length, generally 2 nm tall and having variable widths. High resolution UHV STM images of TSPc aggregates on Au(111) reveal detailed coherent columnar architecture with the phthalocyanine macrocycles orientated parallel to the substrate surface. OMTS was used to identify high energy occupied orbitals, the LUMO of the TSPc aggregates, and the results are contrasted with the same molecular states in unsubstituted metalated phthalocyanines (M.", "author_names": [ "Krista R A Nishida", "Bryan Wiggins", "K W Hipps", "Ursula Mazur" ], "corpus_id": 100793442, "doc_id": "100793442", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Structural and Electronic Properties of Columnar Supramolecular Assemblies Formed from Ionic Metal Free Phthalocyanine on Au(111)", "venue": "", "year": 2011 }, { "abstract": "A compound two dimensional monolayer mixing Mn atoms and 7,7,8,8 tetracyanoquinoclimethane (TCNQ) molecules was synthesized by supramolecular assembly on a Cu(100) surface under ultrahigh vacuum conditions. The interactions in the Mn(TCNQ)(2) network and in the full system arc analyzed from a molecular orbital perspective and in the light of scanning tunneling microscopy (STM) imaging and simulations. Structural, electronic, and magnetic properties are studied in detail using density functional theory (DFT) calculations. In the absence of Cu and depending on the theoretical method used, the TCNQ species can be formally described as either dianions TCNQ(2 interacting with Mn4+ cations according to ligand held theory (using GGA calculations) or, alternatively, as radical monoanions interacting with Mn2+ cations in a high spin state (using GGA+U calculations) In the complete system including a Cu substrate, whatever theoretical method is used, TCNQs appear as dianions interacting with both Mn2+ cations in a high spin state (d(5) and charged copper surface atoms.", "author_names": [ "Xingqiang Shi", "Christian Minot", "Tzu-Chun Tseng", "Steven L Tait", "Nian Lin", "Rui-Qin Zhang", "Klaus Kern", "Jorge I Cerda", "Michel Andre Van Hove" ], "corpus_id": 54633360, "doc_id": "54633360", "n_citations": 24, "n_key_citations": 1, "score": 0, "title": "Structural analysis and electronic properties of negatively charged TCNQ: 2D networks of (TCNQ)2Mn assembled on Cu(100)", "venue": "", "year": 2010 }, { "abstract": "On surface metal organic coordination provides a promising way for synthesizing different two dimensional lattice structures that have been predicted to possess exotic electronic properties. Using scanning tunneling microscopy (STM) and spectroscopy (STS) we studied the supramolecular self assembly of 9,10 dicyanoanthracene (DCA) molecules on the Au(111) surface. Close packed islands of DCA molecules and Au DCA metal organic coordination structures coexist on the Au(111) surface. Ordered DCA3 Au2 metal organic networks have a structure combining a honeycomb lattice of Au atoms with a kagome lattice of DCA molecules. Low temperature STS experiments demonstrate the presence of a delocalized electronic state containing contributions from both the gold atom states and the lowest unoccupied molecular orbital of the DCA molecules. These findings are important for the future search of topological phases in metal organic networks combining honeycomb and kagome lattices with strong spin orbit coupling in heavy metal atoms.", "author_names": [ "Linghao Yan", "Ilona Pohjavirta", "Benjamin Alldritt", "Peter Liljeroth" ], "corpus_id": 143432163, "doc_id": "143432163", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "On Surface Assembly of Au Dicyanoanthracene Coordination Structures on Au(111)", "venue": "Chemphyschem a European journal of chemical physics and physical chemistry", "year": 2019 }, { "abstract": "Two semiconducting naphthalene bisimides were comparatively studied: NBI (TAA)(2) symmetrically N substituted with triaryl amine and asymmetric NBI TAA Oc with triaryl amine and octyl N substituents. Both compounds show very similar spectroscopic and redox properties but differ in their supramolecular organization. As evidenced by STM, in monolayers on HOPG they form ordered 2D structures, however of different packing patterns. NBI (TAA)(2) does not form ordered 3D structures, yielding amorphous thin films whereas films of NBI TAA Oc are highly crystalline. DFT calculations predict the ionization potential (IP) of 5.22 eV and 5.18 eV for NBI TAA Oc and NBI (TAA)(2) respectively, as well as the electron affinity values (EA) of 3.25 eV and 3.22 eV. These results are consistent with the cyclic voltammetry data which yield similar values of IP (5.20 eV and 5.19 eV) and somehow different values of EA 3.80 eV and 3.83 eV) As judged from these data, both semiconductors should exhibit ambipolar behavior. Indeed, NBI TAA Oc is ambipolar, showing hole and electron mobilities of 4.5 x 10( 5) cm(2)(V s) and of 2.6 x 10( 4) cm(2)(V s) respectively, in the field effect transistor configuration. NBI (TAA)(2) is not ambipolar and yields field effect only in the p channel configuration. This different behavior is rationalized on the basis of structural factors.", "author_names": [ "Renata Rybakiewicz", "Joanna Zapala", "David Djurado", "Robert Nowakowski", "Petr Toman", "Jiri Pfleger", "J M Verilhac", "Malgorzata Zagorska", "Adam Pron" ], "corpus_id": 205814513, "doc_id": "205814513", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Naphthalene bisimides asymmetrically and symmetrically N substituted with triarylamine comparison of spectroscopic, electrochemical, electronic and self assembly properties.", "venue": "Physical chemistry chemical physics PCCP", "year": 2013 } ]

[ { "abstract": "The objective of this study was to establish a demo scale plant with 1,000 cubic metres per day (CMD) capacity to recycle industrial wastewater from a semiconductor industry. In this study, two wastewater streams from continuous electrodeionization (CEDI) and local scrubber (LS)/controlled decomposition and oxidation (CDO) with flow rate of 1,335 CMD and 1,012 CMD respectively were chosen to be recycled. For the CEDI reject reclaim system, boron selective resin (BSR) and activated carbon filter (ACF) were utilized to remove boron and total organic carbon (TOC) respectively. The water quality was good enough to be used as ultrapure water (UPW) supply. For the CDO reclaim system, the combination of ACF ultrafiltration (UF) reverse osmosis (RO) under high pH condition was implemented to recycle the local scrubber wastewater (LSW) for cooling tower top up. Product water from both treatment systems was able to meet the target water specifications. The average cost saving was S$0.91/m3 of reclaimed water produced.", "author_names": [ "Chin Yee Eng", "Dongning Yan", "Nipuna Withanage", "Qiyi Liang", "Yue Zhou" ], "corpus_id": 115379024, "doc_id": "115379024", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Wastewater treatment and recycle from a semiconductor industry: A demo plant study", "venue": "Water Practice and Technology", "year": 2019 }, { "abstract": "Industrial Batik production is very well known in East Coast of Peninsular Malaysia especially in Terengganu and Kelantan and in some part of other states in Malaysia such as Perak. This industry traditionally inherited from generation to generation that make big contribution to economic growth due to high demand locally and abroad. However, the industry produces wastewater which contributes to water pollution since it utilizes a lot of chemicals. Preliminary study of the Batik Wastewater contains high reading of Colour and COD that is dangerous to human and aquatic life", "author_names": [ "Abu Bakar", "A S Ahmad Solihin" ], "corpus_id": 202195465, "doc_id": "202195465", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Treatment of Batik Wastewater using Recycled Coagulants from GWTPS (Ground Water Treatment Plant Sludge)", "venue": "", "year": 2019 }, { "abstract": "Efficiency of coagulation flocculation process used for semiconductor wastewater treatment was improved by selecting suitable conditions (pH, polyelectrolyte type, and concentration) through zeta potential measurements. Under this scenario the zeta potential, z, is the right parameter that allows studying and predicting the interactions at the molecular level between the contaminants in the wastewater and polyelectrolytes used for coagulation flocculation. Additionally, this parameter is a key factor for assessing the efficiency of coagulation flocculation processes based on the optimum dosages and windows for polyelectrolytes coagulation flocculation effectiveness. In this paper, strategic pH variations allowed the prediction of the dosage of polyelectrolyte on wastewater from real electroplating baths, including the isoelectric point (IEP) of the dispersions of water and commercial polyelectrolytes used in typical semiconductor industries. The results showed that there is a difference between polyelectrolyte demand required for the removal of suspended solids, turbidity, and organic matter from wastewater (23.4 mg/L and 67 mg/L, resp. It was also concluded that the dose of polyelectrolytes and coagulation flocculation window to achieve compliance with national and international regulations as EPA in USA and SEMARNAT in Mexico is influenced by the physicochemical characteristics of the dispersions and treatment conditions (pH and polyelectrolyte dosing strategy)", "author_names": [ "Eduardo A Lopez-Maldonado", "Mercedes Teresita Oropeza-Guzman", "Adrian Ochoa-Teran" ], "corpus_id": 55556236, "doc_id": "55556236", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Improving the Efficiency of a Coagulation Flocculation Wastewater Treatment of the Semiconductor Industry through Zeta Potential Measurements", "venue": "", "year": 2014 }, { "abstract": "In this work series of photocatalysts based on ZnO modified by Au and Ag2CO3 addition and Ag TiO2 materials were synthesized and evaluated in the treatment of handicrafts factories wastewater and water samples taken from a highly polluted river. In general, it was found that ZnO series were more effective in the bacteria elimination than the commonly used TiO2 semiconductor. It was also observed that the metal (Au, Ag) or silver carbonate addition significantly increases the photocatalytic activity of ZnO and TiO2. It was determined that the content of the metal or carbonate added is an important factor to take into account in order to obtain suitable efficiency in the photocatalytic process, so, for example in the case of the river water samples the increase of Ag2CO3 content from 1 to 5% had a detrimental effect over the bacteria elimination. The optimal conditions for dyes photodegradation and bacteria elimination were found by using a response surface study and the Au ZnO (1% photocatalyst. From this study it was determined that even after recycling this material leads to obtain a removal percentage of these pollutants over than 94%", "author_names": [ "J J Murcia", "J Sastre Hernandez", "Hugo A Rojas", "J Moreno-Cascante", "Pablo Sanchez-Cid", "M C Hidalgo", "Jose Antonio Navio", "C Jaramillo-Paez" ], "corpus_id": 212755842, "doc_id": "212755842", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Evaluation of Au ZnO, ZnO/Ag2CO3 and Ag TiO2 as Photocatalyst for Wastewater Treatment", "venue": "Topics in Catalysis", "year": 2020 }, { "abstract": "Biotechnological processes are important alternatives for water recycling both in hydrometallurgical and mineral processing operations and this paper is focused on two of such technologies: (i) manganese bioremediation and (ii) sulphate reduction. While high concentrations are related to hydrometallurgical operations or AMD generation, manganese is one of the most difficult metals to remove from wastewaters. It is demonstrated herein that a bacterial consortium enriched from a mine water was able to remove 99.7% Mn2+ from a solution containing 50 mg/L. Molecular studies revealed Stenotrophomonas, Bacillus and Lysinibacillus genera in the sample. Cell metabolism resulted in a pH increase and catalysed chemical Mn2+ oxidation. Subsequently, sulphate reduction by sulphate reducing bacteria (SRB) was addressed. A fluidized bed reactor (FBR) in which there was immobilized biomass along with fluidization enabled a high bacterial population >109 cells/mL) in the bioreactor and thus a large sulphate reduction efficiency (97% for a specific sulphate reducing rate of 0.186 0.015 g SO 4 2 /gVSS.d.", "author_names": [ "Natalia Rosana Barbosa", "Sueli Moura Bertolino", "R S Cota", "Versiane A Leao" ], "corpus_id": 99602639, "doc_id": "99602639", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Biotechnologies for Wastewater Treatment in the Mineral Industry", "venue": "", "year": 2017 }, { "abstract": "2Abstrct: In Egypt, the necessity of recycling of refused paper has an economical aspect for water reuse, in plant waste control and by product recovery. The characteristic wastewater stream obtained from four successive composite samples showed high values of COD, BOD and TSS. COD value ranged from 960 to 2300 mg/l, with an average value of 1505 mg/l. The corresponding BOD value ranged between 350 and 1059 mg/l, with an average value of 607 mg/l. Total suspended solids (TSS) and turbidity (NTU) ranged from 652 to 951 mg/l and from 167 to 380 NTU, respectively. Treated effluent characteristics using Alum, aluminum chloride and ferrous sulfate at optimum condition showed that the removal efficiency of COD values were 94.4% and 74 for alum and ferrous sulfate, aluminum chloride, respectively. Corresponding BOD removal values were 91.1% and 85.2 respectively. Residual COD and BOD were 85 mg/l and 50.5 mg/l for alum, respectively. Higher concentration for both residual COD (380 mg/l) and residual BOD (85.2 mg/l) were recorded in case of ferrous sulfate coagulation. It is obvious that using alum as a coagulant is more economically and technically. Based on the obtained results, two treatment alternatives were established. A closed water circuit is achieved, no wastewater leaves the processes. The treated effluent is then utilized to almost 100 Complete recycle of sludge/slurry from the chemical treatment processes were also achieved, the manufacture plant will leave no waste at all.", "author_names": [ "Rifaat Abdel Wahaab", "Ahmed K Moawad", "E A Taleb" ], "corpus_id": 15884919, "doc_id": "15884919", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Wastewater Management and Resource Recovery in Hard Paper Industry: A Case Study", "venue": "", "year": 2010 }, { "abstract": "Textile processing is both water and energy intensive process. Core activities and support activities of the textile industrial unit involves the use water as process water and cooling water in large quantities with subsequent generation of large amount of wastewater. The effluents resulting from these processes differ greatly in composition, due to differences in processes, used fabrics and machinery. It is essential that control measures be implemented to minimize waste generation. Our study involved the development of wastewater management system for a textile industrial unit. This unit dealing with polyester and cotton dyeing and fabric washing. The industrial unit was surveyed for environmental analysis to identify the water consuming and wastewater generations activities, for the adequacy and capacity assessment of the effluent treatment plant. Measures for water conservation and waste minimization through source reduction/ recycling and reuse and for treatment of wastewater that are cost effective and compliance with the standards have been developed. Results shows that with implementing measures for source reduction, reuse and recycle at all feasible places have reduced water consumption, wastewater generation and steam consumption in the industrial unit.", "author_names": [ "Arshdeep Kaur", "Akepati S Reddy" ], "corpus_id": 134110763, "doc_id": "134110763", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Wastewater management study for a textile processing industry", "venue": "", "year": 2013 }, { "abstract": "Water treatment industry should focus more on water recycling and reuse due to global water shortages as a result of climate change and the increase in volume of toxic and recalcitrant industrial effluents from textile, pharmaceutical and pesticide industries. Water recycling and reuse, which often require sustainable system and high technology should be cost efficient and environmentally friendly. Advanced Oxidation Process (AOP) is widely employed to remove very resistant pollutants that are difficult or costly to treat, this treatment system will dominate the future of water recycle and reuse. Researches focusing on application of such technology recommended titanium dioxide (TiO2) as the preferred catalyst and have carried out investigations and recommend improvements in areas of mass transfer and photon transfer limitations as related to photoreactor intensification processes. These studies have shown potential in the way the photoreactors are designed. Despite such developments, the technology is yet to replace the existing treatment systems in the industry. Data collected from unpublished survey of over 80 major global water treatment companies in July and August 2014, revealed that only about 43% used some forms of AOP, mostly UV and Ozonation. Only about 4% used photocatalysis at pilot scale. Application of photoreactors will be more challenging in textile wastewater treatment due to the presence of ions Cl NO3 SO42 CO32 and PO43 from dissolved salts, they act as inhibitors and poisons that deactivate Titanium oxide (TiO2) reactor beds. This paper reported the findings and recommended solutions for the deactivation phenomenon.", "author_names": [ "Hamisu Umar Farouk", "Abdul Aziz Abdul Raman", "Wan Mohd Wan Daud" ], "corpus_id": 113717689, "doc_id": "113717689", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Commercial viability of photoreactors in textile wastewater treatment hindered by Titanium dioxide (TiO2) deactivation", "venue": "", "year": 2015 }, { "abstract": "The research proposes the method for cleaning of the chromium containing wastewater by the modified sorbents based on the natural aluminosilicates of East Kazakhstan deposits, local wood waste and fibrous materials that differ by cheap, good sorption properties, availability and security in the environmental terms. The research of the waste complex sorbents for utilization in one of the most resource intensive industries the construction industry is highly relevant and promising to create the necessary preconditions for the industrial development of the construction binders for various technology areas. The application of the research results will make sound recommendations how to expand the resource base, to use industrial raw materials in the production process, and to reduce the cost of widely used materials and products in the construction practice. The important factor in the technical and economic term is that the residue from the treated waste water is environmentally friendly since the chromium ions and other heavy metals have the form of the complex compounds. The complex compounds are environmentally safe and can be recycled in various building materials. The optimal construction materials for the utilization of the waste sorbents are mortar and concrete.", "author_names": [ "Gulzhan Daumova", "Saule A Abdulina", "Gulnara A Kokayeva", "Akzhigitova Meruert", "" ], "corpus_id": 115138597, "doc_id": "115138597", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Experimental Studies on Wastewater Sorption Treatment with Subsequent Disposal of Used Sorbents", "venue": "", "year": 2018 }, { "abstract": "Water is the main source of life on the planet and due to the influence of advanced technologies and industries related to them, water is being polluted. Environmental engin eers face a lot of challenges in controlling the hazards of water pollution. Membrane technologies are receiving special recognition as alternatives to convectional water treatment and as a means of polishing treated wastewater effluent for sense applications. The most common ones are microfiltration (MF) ultra filtration (UF) reverse osmosis (RO) and Nano filtration (NF) membrane. Micro filtration is a filtration process which removes the contaminants from a liquid or a gas by passing it through a micro porous membrane. Bioreactors convert or produce materials using functions naturally endowed to living creatures and Membrane Bioreactors (MBR) systems essentially consists of combination of membrane and biological reactor system. In general, MBR applicati ons for wastewater treatment can be classified into four groups, namely, Extractive Membrane Reactors, Bubbles less Aeration Membrane Bioreactors, Recycle Membrane Reactors and Membrane Separation Reactors. EMBR enhance the performance capabilities of biol ogical treatment of wastewater by exploiting the membrane's ability to achieve a high degree of separation while allowing transport of components from one phase to another and can be operated in two different modes. MABR use gas permeable membranes to directly supply high purity oxygen without bubble formation to a biofilm. RMBR consists of a reaction vessel operated as a stirred tank reactor and an externally attached membrane module. Application of MSBR (micro or ultra filtration) techniques for biosolid separation in a conventional activated sludge process can overcome the disadvantages of the sedimentation and biological treatment steps. The presentation aims at comparing the principle, operation and performance of these four types of MBRs with respect to industrial effluent treatment elaborately.", "author_names": [ "T Thasan", "Anbalagan Anantharaj" ], "corpus_id": 110815639, "doc_id": "110815639", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Comparative Study On The Performance Of Four Novel Membrane Bioreactors (EMBR, MABR, RMBR, MSBR) For Wastewater Treatment", "venue": "", "year": 2013 } ]

[ { "abstract": "Contributors. Preface. Gallium Nitride (GaN) (V. Bougrov, et al. Aluminum Nitride (AIN) (Y. Goldberg) Indium Nitride (InN) (A. Zubrilov) Boron Nitride (BN) (S. Rumyantsev, et al. Silicon Carbide (SiC) (Y. Goldberg, et al. Silicon Germanium (Si 1 xGe x) (F. Schaffler) Appendix 1: Basic Physical Constants. Appendix 2: Periodic Table of the Elements. Appendix 3: Rectangular Coordinates for Hexagonal Crystal. Appendix 4: The First Brillouin Zone for Wurtzite Crystal. Appendix 5: Zinc Blende Structure. Appendix 6: The First Brillouin Zone for Zinc Blende Crystal. Additional References.", "author_names": [ "M E Levinshtein", "Sergey Rumyantsev", "Michael S Shur" ], "corpus_id": 136897631, "doc_id": "136897631", "n_citations": 1416, "n_key_citations": 52, "score": 0, "title": "Properties of advanced semiconductor materials GaN, AlN, InN, BN, SiC, SiGe", "venue": "", "year": 2001 }, { "abstract": "It has been recognized that Raman scattering spectroscopy is a powerful tool to characterize SiC crystals non destructively. We review recent significant developments in the use of Raman scattering to study structural and electronic properties of SiC crystals. The areas to be discussed in the first part include polytype identification, evaluation of stacking disorder and ion implantation damages, and stress evaluation. The Raman scattering by electronic transitions is discussed in the second part of this article. We concentrate on the plasmon LO phonon coupled modes whose spectral profiles are used to evaluate the carrier concentration and mobility. Anisotropic electronic properties of a SiC and characteristics of heavily doped crystals are discussed. Semiconductor to metal transition and Fano interference effect are also treated.", "author_names": [ "Shin-ichi Nakashima", "Hiroshi Harima" ], "corpus_id": 121826054, "doc_id": "121826054", "n_citations": 665, "n_key_citations": 10, "score": 0, "title": "Raman Investigation of SiC Polytypes", "venue": "", "year": 1997 }, { "abstract": "Fityk is portable, open source software for nonlinear curve fitting and data analysis. It specializes in fitting a sum of bell shaped functions to experimental data. In particular, it enables Pawley refinement of powder diffraction data and size strain analysis.", "author_names": [ "Marcin Wojdyr" ], "corpus_id": 98051756, "doc_id": "98051756", "n_citations": 1594, "n_key_citations": 83, "score": 0, "title": "Fityk: a general purpose peak fitting program", "venue": "", "year": 2010 }, { "abstract": "Abstract Neutron irradiation induced defects in 3C SiC irradiated to 2.8 4.2 x 10 26 n/m 2 at 480 735 degC were investigated by XRD measurement, isochronal annealing and DFT calculation. The XRD peak shift revealed different features between the specimens irradiated at 480 degC and higher temperature than 585 degC. The peak shifts were larger at the higher angle in the specimen irradiated at 480 degC, while the specimens irradiated at higher temperature than 585 degC, amounts of their peak shifts were not simply related to the diffraction angles. Crystal lattice of the specimen irradiated at 480 degC was considered to expand isotropically due to the irradiation. On the other hand, that of the specimens irradiated at higher temperature than 585 degC would expand anisotropically. Modification of XRD profile by the formation of various kinds of point defects and their clusters in 3C SiC was simulated using Rietveld method based on the DFT calculation results. Formation of the C C100 dumbbell complex defect expressed well the XRD peak shifts of 3C SiC irradiated above 585 degC.", "author_names": [ "Takashi Sawabe", "Masafumi Akiyoshi", "Katsumi Yoshida", "Toyohiko Yano" ], "corpus_id": 97642309, "doc_id": "97642309", "n_citations": 29, "n_key_citations": 0, "score": 1, "title": "Estimation of neutron irradiation induced defect in 3C SiC from change in XRD peak shift and DFT study", "venue": "", "year": 2011 }, { "abstract": "We uncover the constitutive relation of graphene and probe the physics of its optical phonons by studying its Raman spectrum as a function of uniaxial strain. We find that the doubly degenerate E(2g) optical mode splits in two components: one polarized along the strain and the other perpendicular. This splits the G peak into two bands, which we call G( and G( by analogy with the effect of curvature on the nanotube G peak. Both peaks redshift with increasing strain and their splitting increases, in excellent agreement with first principles calculations. Their relative intensities are found to depend on light polarization, which provides a useful tool to probe the graphene crystallographic orientation with respect to the strain. The 2D and 2D( bands also redshift but do not split for small strains. We study the Gruneisen parameters for the phonons responsible for the G, D, and D( peaks. These can be used to measure the amount of uniaxial or biaxial strain, providing a fundamental tool for nanoelectronics, where strain monitoring is of paramount importance.", "author_names": [ "T M G Mohiuddin", "Antonio Lombardo", "Rahul R Nair", "Alessandro Bonetti", "Gianluca Savini", "Rashid Jalil", "Nicola Bonini", "Denis M Basko", "Costas Galiotis", "Nicola Marzari", "Kostya S Novoselov", "Andre K Geim", "Andrea C Ferrari" ], "corpus_id": 36827580, "doc_id": "36827580", "n_citations": 1371, "n_key_citations": 48, "score": 0, "title": "Uniaxial Strain in Graphene by Raman Spectroscopy: G peak splitting, Gruneisen Parameters and Sample Orientation", "venue": "", "year": 2009 }, { "abstract": "Abstract Hydroxyapatite (HA) nanoparticles were prepared by microwave synthesis method and the obtained powder is annealed at 800 degC for 2 h. The annealed HA particles were characterized by X ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy methods. The HA size and morphology were examined using a transmission electron microscope (TEM) The XRD results reveal that the diffraction peaks of the annealed HA were of well crystalline and correspond to the hexagonal crystal structure. The XRD and FTIR results confirm the absence of secondary phases such as b tricalcium phosphate (b TCP) and calcium oxide in annealed HA particles. The TEM result confirms the hexagonal structure of annealed HA and the particles were observed to be of ellipsoid like shaped morphology with less agglomeration. The lattice strain, crystallite size, lattice deformation stress and deformation energy density for annealed (800 degC) HA nanoparticles were estimated by Williamson Hall isotropic strain model W H ISM) W H anisotropic strain model W H ASM) and W H energy density model W H EDM) based on Williamson Hall W H plot from powder X ray diffraction data. The results of estimated average crystallite size of annealed HA by Scherrer and W H plot methods were compared with TEM results. It is found that the average crystallite size measured by W H plot methods is in good agreement with TEM results.", "author_names": [ "K Venkateswarlu", "Arumugam Chandra Bose", "N Rameshbabu" ], "corpus_id": 120026613, "doc_id": "120026613", "n_citations": 287, "n_key_citations": 7, "score": 0, "title": "X ray peak broadening studies of nanocrystalline hydroxyapatite by Williamson Hall analysis", "venue": "", "year": 2010 }, { "abstract": "A strong substrate graphite bond is found in the first all carbon layer by density functional theory calculations and x ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over] 4H SiC surfaces. We also present evidence of a charge transfer that depends on the interface geometry. Hence the graphene is doped and a gap opens at the Dirac point after three Bernal stacked carbon layers are formed.", "author_names": [ "F Varchon", "R Feng", "Joanna Hass", "Xiaofeng Li", "B Ngoc Nguyen", "Cecile Naud", "Pierre Mallet", "Jean Yves Veuillen", "Claire Berger", "Edward H Conrad", "Laurence Magaud" ], "corpus_id": 26406232, "doc_id": "26406232", "n_citations": 562, "n_key_citations": 8, "score": 0, "title": "Electronic structure of epitaxial graphene layers on SiC: effect of the substrate.", "venue": "Physical review letters", "year": 2007 }, { "abstract": "Abstract The XRD Omega method was used to determine the residual stress in a CVD diamond coating deposited on a SiC substrate. The (4 0 0) plane of CVD diamond was used with a tilt angle (ps) from 0 to 60 degrees. A compressive stress of 130 MPa with a standard deviation (SD) value of 28 MPa was obtained. Stress results obtained from the indentation method and Raman spectroscopy analysis were also compared with the XRD stress values. Indentation testing of the CVD diamond was performed using a microhardness tester with a Vickers diamond indenter under a load of 1 2.5 kgf. All stress values obtained correlated closely to results obtained by XRD. These results collectively illustrate that these coatings contain compressive stress associated with their deposition process.", "author_names": [ "S P Chowdhury", "M T Laugier", "John Henry" ], "corpus_id": 136832719, "doc_id": "136832719", "n_citations": 34, "n_key_citations": 2, "score": 0, "title": "XRD stress analysis of CVD diamond coatings on SiC substrates", "venue": "", "year": 2007 }, { "abstract": "Abstract Preliminary XPS and XRD studies of the 3C SiC polycrystals (with the grain size of order of 100 mm) grown by the sublimation method were performed. The XRD data proved a dominant 3C SiC structure accompanied by an admixture of the residual 6H SiC phase. The main core level photoelectron spectra were analysed in detail. In particular, the C 1s level spectrum revealed a three peaks structure containing the peak indicative of free carbon as well as the remaining two identified as the carbidic components, centered at E B a =282.3 eV and E B b =283.4 eV. The fact, that the most intensive peak 'a' was found especially well resolvable in the acquired spectrum (as not observed in the earlier reports) was linked with a dominance of 3C SiC phase and a relatively high lattice perfection of the crystals studied. Therefore, it enabled us a reliable identification of the main C 1s line component (peak 'a' as related to the C Si bond in cubic Si 1 x C x crystal with slight deviation from stoichiometry (0.5 x 0.54) On the other hand, the minor carbidic component (peak 'b' was ascribed to the C Si bond in the highly C saturated cubic Si 1 x C x x 0.6) compound that is present in the surface region.", "author_names": [ "Ryszard J Iwanowski", "Krzysztof Fronc", "Wojciech Paszkowicz", "Markku Heinonen" ], "corpus_id": 94790684, "doc_id": "94790684", "n_citations": 74, "n_key_citations": 0, "score": 0, "title": "XPS and XRD study of crystalline 3C SiC grown by sublimation method", "venue": "", "year": 1999 }, { "abstract": "The crystal quality, stress and strain of GaN grown on 4H SiC and sapphire are characterized by high resolution X ray diffraction (HRXRD) and Raman spectroscopy. The large stress in GaN leads to the generation of a large number of dislocations. The Raman stress is determined by the results of HRXRD. The position and line shape of the A1 longitudinal optical (LO) phonon mode is used to determine the free carrier concentration and electron mobility in GaN. The differences between free carrier concentration and electron mobility in GaN grown on sapphire and 4H SiC are analyzed.", "author_names": [ "Duan Huantao", "Gu Wen-Ping", "Zhang Jincheng", "Hao Yue", "Chen Chi", "Ni Jin-Yu", "Xu Shengrui" ], "corpus_id": 110347890, "doc_id": "110347890", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Characterization of GaN grown on 4H SiC and sapphire by Raman spectroscopy and high resolution XRD", "venue": "", "year": 2009 } ]

[ { "abstract": "Motivated by the recently demonstrated ability to attach quantum dots to polymers at well defined locations, we propose a condensed phase analog of the ion trap quantum computer: a scheme for quantum computation using chemically assembled semiconductor nanocrystals attached to a linear support. The linear support is either a molecular string (e.g. DNA) or a nanoscale rod. The phonon modes of the linear support are used as a quantum information bus between the dots. Our scheme offers greater flexibility in optimizing material parameters than the ion trap method, but has additional complications. We discuss the relevant physical parameters, provide a detailed feasibility study, and suggest materials for which quantum computation may be possible with this approach. We find that Si is a potentially promising quantum dot material, already allowing a 5 10 qubit quantum computer to operate with an error threshold of 10 3", "author_names": [ "Kenneth R Brown", "Daniel A Lidar", "K Birgitta Whaley" ], "corpus_id": 3745458, "doc_id": "3745458", "n_citations": 35, "n_key_citations": 0, "score": 1, "title": "Quantum computing with quantum dots on quantum linear supports", "venue": "", "year": 2001 }, { "abstract": "", "author_names": [ "Andrew J Landahl" ], "corpus_id": 125102832, "doc_id": "125102832", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Universal fault tolerant adiabatic quantum computing with quantum dots or donors", "venue": "", "year": 2016 }, { "abstract": "We explore the pattern of frequency dependent linear and second non linear optical responses of repulsive impurity doped quantum dots harmonically confined in two dimensions. The dopant impurity potential chosen assumes a Gaussian form and it is doped into an on center location. The quantum dot is subject to a periodically oscillating external electric field. For some fixed values of transverse magnetic field strength (oc) and harmonic confinement potential (o0) the influence of impurity strength (V0) and impurity domain (x) on the diagonal components of the frequency dependent linear (axx and ayy) and second non linear (gxxxx and gyyyy) responses of the dot are computed through a linear variational route. The investigations reveal that the optical responses undergo enhancement with increase in both V0 and x values. However, in the limitingly small dopant strength regime one observes a drop in the optical responses with increase in V0. A time average rate of energy transfer to the system is often invoked to support the findings.", "author_names": [ "Nirmal Kumar Datta", "Manas Kumar Ghosh" ], "corpus_id": 119923088, "doc_id": "119923088", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "Impurity strength and impurity domain modulated frequency dependent linear and second non linear response properties of doped quantum dots", "venue": "", "year": 2011 }, { "abstract": "Abstract A two qubit quantum gate scheme is proposed in a system of semiconductor quantum dots (QDs) located in a high Q single mode optical cavity with extremely low loss. The spin degrees of freedom of the only excess conduction electron of the QD are employed as qubits. By means of properly tailored ultrafast laser pulses and Pauli blocking effects, we can perform conditional phase gate on two non neighboring spins, mediated by the cavity mode.", "author_names": [ "Mang Feng", "Irene D'Amico", "Paolo Zanardi", "Fausto Rossi" ], "corpus_id": 119427592, "doc_id": "119427592", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A scheme of quantum computing with semiconductor quantum dots in optical cavity", "venue": "", "year": 2003 }, { "abstract": "An all carbon memristive synapse is highly desirable for hardware implementation in future wearable neuromorphic computing systems. Graphene oxide (GO) can exhibit resistive switching (RS) and may be a feasible candidate to achieve this objective. However, the digital type RS often occurring in GO based memristors restricts the biorealistic emulation of synaptic functions. Here, an all carbon memristive synapse with analog type RS behavior was demonstrated through photoreduction of GO and N doped carbon quantum dot (NCQD) nanocomposites. Ultraviolet light irradiation induced the local reduction of GO near the NCQDs, therefore forming multiple weak conductive filaments and demonstrating analog RS with a continuous conductance change. This analog RS enabled the close emulation of several essential synaptic plasticity behaviors; more importantly, the high linearity of the conductance change also facilitated the implementation of pattern recognition with high accuracy. Furthermore, the all carbon memristive synapse can be transferred onto diverse substrates, showing good flexibility and 3D conformality. Memristive potentiation/depression was stably performed at 450 K, indicating the resistance of the synapse to high temperature. The photoreduction method provides a new path for the fabrication of all carbon memristive synapses, which supports the development of wearable neuromorphic electronics. A graphene based device can help computer chips behave more like human brains by transmitting current across thread like wires. Neural synapses store memories by accessing different types of conductive states. Chinese researchers led by Haiyang Xu at Northeast Normal University in Changchun and Zhenhui Kang at Soochow University in Suzhou now demonstrate that graphene sheets with different conductivity levels caused by adding or removing oxygen atoms can also exhibit synapse like behavior. The team developed a carbon nitrogen composite to sandwich between two graphene electrodes with high and low levels of conductivity. Exposing the composite to ultraviolet light created numerous tiny filaments between the electrodes that physically restrict electron flow and provide gradual smooth transitions between the graphene electrodes' two conductive states. The organic framework of this device also provides inherent flexibility for wearable devices. All carbon memristive synapse is built through photo reduction of a nanocomposite comprised of graphene oxide and N doped carbon quantum dots. The analog type resistive switching was demonstrated, which enabled the emulation of synaptic learning and pattern recognition with high accuracy. The all carbon devices possess excellent transferability, flexibility and resistance to high temperature, showing the potential for the development of wearable neuromorphic computing system.", "author_names": [ "Y Y Lin", "Zhongqiang Wang", "Xue Zhang", "Tao Zeng", "Liang Bai", "Zhenhui Kang", "Changhua Wang", "Xiaoning Zhao", "Haiyang Xu", "Yichun Liu" ], "corpus_id": 221884121, "doc_id": "221884121", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Photoreduced nanocomposites of graphene oxide/N doped carbon dots toward all carbon memristive synapses", "venue": "NPG Asia Materials", "year": 2020 }, { "abstract": "Control over electron spin states, such as coherent manipulation, filtering and measurement promises access to new technologies in conventional as well as in quantum computation and quantum commu nication. We review our proposal of using electron spins in quantum confined structures as qubits and discuss the requirements for implementing a quantum computer. We describe several realizations of one and two qubit gates and of the read in and read out tasks. We discuss recently proposed schemes for using a single quantum dot as spin filter and spin memory device. Considering electronic EPR pairs needed for quantum communication we show that their spin entanglement can be detected in meso scopic transport measurements using metallic as well as superconducting leads attached to the dots.", "author_names": [ "Guido Burkard", "Hans-Andreas Engel", "Daniel Loss" ], "corpus_id": 1905668, "doc_id": "1905668", "n_citations": 95, "n_key_citations": 0, "score": 0, "title": "Spintronics and quantum dots for quantum computing and quantum communication", "venue": "", "year": 2000 }, { "abstract": "Since the seminal work by Shor who proposed a quantum algorithm factorizing integers into prime factors, it has become manifest that the laws of quantum mechanics provide resources for computation that overpower classical physics. The computational advantages that quantum physics offers have stimulated a tremendous amount of theoretical and experimental research. In this context, spin systems have played a major role, given that the spin degree of freedom with the paradigmatic case of the spin 1/2 of electrons represents an obvious candidate for the encoding of an elementary bit of quantum information (qubit) On the other hand, however, quantum objects are very fragile entities, being very susceptible to the environment they reside in. This fragility of qubits is one of the main obstacles in the realization of a quantum computer. In this thesis, we mainly address the two following questions relevant to quantum computation. i) How is it possible to realize quantum gates both in a reliable and scalable way? ii) How can we store quantum information in a way that is resilient to the errors caused by the thermal environment? We focus on spin systems and demonstrate that long range spin spin interactions in the models considered can have beneficial effects. In their pioneering work, Loss and DiVincenzo proposed a way to perform quantum computation in a semiconductor based architecture where the spin state of an electron trapped in a quantum dot is chosen to encode the elementary qubit. In this proposal, the spins are required to lie spatially close to each other, and this might complicate the realization of a scalable architecture. In the first part of the thesis we thus propose a scheme that allows the constraint on the positioning of the qubits to be relaxed. This is achieved by introducing a ferromagnetic coupler between the distant qubits, to which it is coupled via a dipolar interaction. Most importantly, our proposal is applicable to any type of spin qubits and in particular to the technologically very relevant silicon based qubits and NV centers in diamond to which previous coupling schemes do not apply. As additional key element, a quantum computer needs a memory capable of reliably storing quantum information in the presence of thermal fluctuations. This brings us to the second part of this thesis, where we consider self correcting memories, for which the protection against thermal noise is built in at the hardware level. We propose physical models that exhibit these self correcting properties, using as a starting point the well known topologically ordered toric code. In particular, we investigate how to induce long range interactions between the spins of the toric code, since such interactions help increase the memory lifetime. As a first step, we study a honeycomb quantum spin model coupled to delocalized cavity modes. We investigate the properties of the low energy toric code Hamiltonian and show that the coupling to cavity modes prolongs the lifetime of the memory and offers a method to detect the presence of excitations. While the introduction of extended bosonic modes makes the model non local, we also propose a purely local model consisting of a toric code embedded in a three dimensional cubic lattice of hopping bosons; the low energy sector of a toric code coupled to a three dimensional Heisenberg ferromagnet in a broken symmetry state realizes this model. Our analysis leads to an energy penalty for the creation of defects that grows linearly with the size L of the memory and thus to a lifetime increasing exponentially with L. In the third part of this thesis, we study spin systems that support anyons, i.e. particles with fractional statistics. Similar to the toric code, such systems are topologically ordered: they are immune to local perturbations and quantum gates are implemented by non local operations, namely the exchange of anyons, whose outcomes depend only on the topology of the exchange. Here again the fault tolerance is achieved at the level of the hardware and physical systems supporting non abelian anyons are thus promising platforms for quantum computation. We focus on spin systems that exhibit some of these properties and specifically on variations of the honeycomb quantum spin model. We first investigate the exact solution of the honeycomb model in detail and derive an explicit formula for the projector onto the physical subspace. We use this result to study inhomogeneous open spin ladders, related to the honeycomb model, which can be tuned between topological and non topological phases. We test the robustness of Majorana end states (MES) which emerge at the boundary between sections in different topological phases. Furthermore, we present a trijunction setup where MES can be braided. This is of interest since MES in these spin ladders potentially follow non abelian braiding statistics. Finally, we study the ground states of the aforementioned ladders and show that they are free of vortices when the signs of the spin couplings are all positive or negative. To prove this, we use exact reflection positivity based methods as well as approximate methods. In the last part of the thesis, we provide an extension of the Mermin Wagner theorem to a system of lattice spins that are spin coupled to itinerant and interacting charge carriers. We prove that neither (anti ferromagnetic nor helical long range order is possible in one and two dimensions at any finite temperature (in the absence of spin orbit) The fundamental question whether spontaneous ordering of the lattice spins occurs in these systems is of interest in the context of quantum computation; the polarization of nuclear spins coupled to a two dimensional electron gas is a possible route towards the reduction of decoherence induced by the fluctuating Overhauser field in gate defined quantum dots.", "author_names": [ "Fabio L Pedrocchi" ], "corpus_id": 117834308, "doc_id": "117834308", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Spin systems and long range interactions for quantum memories and quantum computing", "venue": "", "year": 2013 }, { "abstract": "The support by the ISEN Booster Award has significantly advanced our group's research, resulting in 4 publications in Journal of Chemical Physics and Journal of Chemical Theory and Computation. In addition, the support by ISEN has allowed us to obtain two federal grants: a regular grant from Department of Energy Basic Energy Sciences and the National Science Foundation CAREER Award (to be annouced) I have presented 6 invited talks in international conferences, including the Sanibel Symposium, Telluride meetings, and the ACS 2013 Fall meeting. In the following, I will summarize our research achievements during the support by ISEN, and future directions. We have developed a wave function ansatz based on tensor decompositions, Ps i ui+ i ui2 i ui 1/4 i ui2 in order to apply rigorous wave function methods to nanoscale materials including quantum dots. We decided to test our hypothesis using a simple system, a molecular dimer, which itself is interesting in solar energy conversoin. In the article that we published in J. Chem. Phys. we demonstrated that the active space wave functions of molecular dimers can be compactly represented by a linear combination of monomer wave functions as Ps i ui+ \" i ui 1/4 i ui 1/4 This expansion becomes exact when a large number of states are included in the summation. Figure 1 shows the numerical proof of potential exactness using a benzene dimer. Importantly we have found that the Hamiltonian matrix elements between product basis functions can be computed without forming dimer basis functions explicitly:", "author_names": [ "Tamar Seideman", "Mark A Ratner", "Toru Shiozaki" ], "corpus_id": 14078256, "doc_id": "14078256", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Year End Report Accurate Electronic Structure Theory of Quantum Dots", "venue": "", "year": null }, { "abstract": "for an Invited Paper for the MAR05 Meeting of The American Physical Society Transport Spectroscopy of Coupled Quantum Dots in Conditions of the Kondo Effect LEONID GLAZMAN, University of Minnesota We develop electron transport theory for novel devices [1,2] which are interesting in the context of correlated electrons physics. The device proposed in Ref. [1] is designed for an observation of a non Fermi liquid behavior of itinerant electrons. The device measured in Ref. [2] may serve a similar purpose, and also may become important for quantum computing. In the case of Ref. [1] our theory [3] provides a strategy for tuning to the non Fermi liquid fixed point a quantum critical point in the space of device parameters. We explore the corresponding quantum phase transition, and make explicit predictions for the behavior of differential conductance in the vicinity of the quantum critical point. Motivated by the measurements [2] we developed a theory of conductance of Kondo quantum dots coupled by the RKKY interaction [4] Investigation of the differential conductance at fixed interaction strength may allow one to distinguish between the possible ground states of the system. Transition between the ground states is achieved by tuning the interaction strength; the nature of the transition (which includes a possibility of a non Fermi liquid point) can be extracted from the temperature dependence of the linear conductance. This research is supported by NSF grants DMR02 37296 and EIA0210736. 1. Y. Oreg and D. Goldhaber Gordon, Phys. Rev. Lett. 90, p. 136602 (2003) 2. N.J. Craig J.M. Taylor, E.A. Lester, C.M. Marcus, M.P. Hanson, and A.C. Gossard, Science 304, 565 (2004) 3. M.G. Vavilov and L.I. Glazman, preprint cond mat/0404366. 4. M. Pustilnik, L. Borda, L.I. Glazman, and J. von Delft, Phys. Rev. B 69, 115316 (2004)", "author_names": [ "Leonid I Glazman" ], "corpus_id": 118796445, "doc_id": "118796445", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Transport Spectroscopy of Coupled Quantum Dots in Conditions of the Kondo Effect", "venue": "", "year": 2005 }, { "abstract": "This paper describes the design of different type of combinational such as adder subtractor preceding NAND, NOR, XOR, XNOR based on QCA design, with comparatively less number of cells and area. It is efficient for its faster speed ,smaller size and low power consumption than transistor technology.QCA provides for nano level computations using molecular component .QCA Designer gives the designer the ability to quickly layout a QCA design by providing an extensive set of CAD tools.By taking full advantage of the unique features of this technology, we are able to create complete circuits on a single layer of QCA. Keywords component, QCA, combinational circuits, majority gates, QCA designer. I.INTRODUCTION The size of CMOS transistors are decreasing day by day and it will eventually hits its limitations hence it become necessary to develop an alternate to continually improve the development of electronics devices .Devices based on quantum mechanical principles hold the promise of faster speeds and greatly reduced sizes. Most quantum device designs examined have been similar to classical device implementations in that they use currents and voltages to encode information.QCA is a potential device That can be used to implement the sequential and the combinational circuits. It is a different type of technology that will replace MOSFET in future. QCAs were introduced in 1993 by lent et al, and experimentally verified in 1997. It is expected to achieve high device density, extremely low power consumption and very high switching speed .The QCA offers a new transistorless computing paradigm in nanotechnology. QCA can be used to create s smaller electronics device with high computation switching speed and low power consumption. this make research on QCA popular and important to replace CMOS transistors in Nano scale technology fabrication. II.QCA BASICS A QCA consists of an array of quantum dot cells connected locally by the interactions of the electrons contained in each cell. The scheme is non conventional in that the quantum state of each cell is used to encode binary information. The Coulombic interaction connects the state of one cell to the state of its neighbors. Thus the problems associated with small output currents and parasitic capacitances of connecting wires do not occur. \"Binary wires\" composed of linear arrays of cells are effective in transmitting information, coded in the cell states, from one place to another. By applying these layouts, the hardware requirements for a QCA design can be reduced. QCA is based on electrons confining in dots and each cell has four quantum Dots The four dots are located in the corners of squares structure as shown in fig 1.The cell contains two extra mobile electrons, which are allowed to tunnel between neighboring sites of the cell. Coulombic repulsion causes the electrons to occupy antipodal sites within the cell. These two bistable states result in cell polarizations of P +1(binary 1) and P 1(binary 0) and one Null state P=0 as shown below in Fig.1. Proceedings of National Conference on Recent Advances in Electronics and Communication Engineering (RACE 2014) 28 29 March 2014 2 QCA cells transfer information by the propagation of polarized charge instead of flow of current thus, QCA circuits have lower energy and higher processing speed. The power needed to perform the polarization changes in cells (that support logic operations) is supplied by the clock signal. A.QCA WIRE In a QCA wire, the binary signal propagates from input to output because of the electrostatic interactions between cells. Since the polarization of each cell tends to align with that of its neighbors, a linear arrangement of standard cells can be used to transmit binary information from one point to another. A QCA wire is needed to transmit signals. The wire consists of chain of cells where the cells are coupled to each other. Logic values are passed from cell to cell due to the coloumbic interactions. The polarization of input cell is propagated down the wire .Any cell along the wire that are anti polarized to the input would be at a higher energy level and would soon settle to the correct ground state. The propagation in a 90deg QCA wire is shown in Fig. 2. Another is 45deg QCA wire, in Fig.3. In this case, the propagation of the binary signal alternates between the two polarizations. B.QCA INVERTER Two standard cells in a diagonal orientation are geometrically similar to two rotated cells in a horizontal orientation. For this reason, standard cells in a diagonal orientation tend to align in opposite polarization directions as in the inverter chain. This anti aligning behavior can be used in designing a QCA inverter. The electrostatic interaction is inverted, as the quantum dots corresponding to different polarizations are misaligned between the cells as in Fig. 4(a) There are several inverter types. Inverter of two cells is shown in Fig. 4(b) Proceedings of National Conference on Recent Advances in Electronics and Communication Engineering (RACE 2014) 28 29 March 2014 3 The \"signal\" comes in from the left on a binary and splits into two parallel wires which are offset from the original. Because the incoming wire extends one cell beyond the beginning of the offset wires, aligning effects dominate at the branch point. Since the horizontal and vertical interactions are dominant, the signal in the two offset wires always matches that of the incoming wire. At the right end of the inverter, the offset wires rejoin into one. However, there are no horizontal or vertical interactions at this end, so the diagonal interactions cause the signal to be inverted. C.PROGRAMMABLE LOGIC GATE The fundamental QCA logical device is a 3 input majority gate, shown in Fig.5. from which more complex circuits can be built. The central cell, labeled the device cell, has three fixed inputs, labeled A, B, and C. The device cell has its lowest energy state if it assumes the polarization of the majority of the three input cells. The inputs to a particular device can come from previous calculations or be directly fed in from array edges. Figure 5(a) shows an arrangement of five standard cells. The states of the cells on the top, left, and bottom are fixed, while the center and right cells are free to react to the fixed charge. In an actual implementation, the three neighbors would not be fixed; they would be driven by results of previous calculations or by inputs at the edge of the QCA. In the particular case shown, two of the inputs are in the \"one\" state, and the other is in the \"zero\" state. When we solve for the ground state of the free cells, we find that they both match the state of the majority of the fixed neighbors. We refer to this result, which is true for all combinations of the three inputs, as majority voting logic. To represent this new logical function, we will use the symbol shown in Fig. 5(b) As this symbol demonstrates, there are three inputs and one output for such a logic gate. Figure 5(c) shows the truth table for a majority voting logic gate. This is a summary of our simulation of all eight combinations of the three inputs. The majority voting logic function can be expressed in terms of fundamental Boolean operators as M(A,B,C) =AB+ BC+AC. Proceedings of National Conference on Recent Advances in Electronics and Communication Engineering (RACE 2014) 28 29 March 2014 4 Figure 5 Qca Majority Gate", "author_names": [ "Aditi Dhingra", "Aprana Goel", "G Verma", "Rashmi Chawla" ], "corpus_id": 49486521, "doc_id": "49486521", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Combinational Circuit Design using Advanced Quantum Dot Cellular Automata", "venue": "", "year": 2014 } ]

[ { "abstract": "Mismatch of power supply integrity of power delivery network (PDN) between an automatic test equipment (ATE) and a customer board can lead to test failures such as overkills or underkills during semiconductor test. This paper proposes a technique to control the power supply impedance on an ATE using compensation current injection so that it emulates the impedance on a customer board. Digital filter is used to calculate compensation current waveform in real time in response to the measured power supply voltage fluctuation. Its implementation is based on the PDNs of both the ATE and the customer board. This paper introduces the filter implementation methodology for arbitrary PDN using nested feedback loop of digital filter, as well as experimental results of prototype circuits. This paper demonstrates that with the proposed current injection the power supply voltage fluctuation waveform on the ATE matches up with that on the customer board, which means that the compensation current injection successfully controls and emulates the impedance. With the proposed technique test failures caused by the impedance difference between the two environments are reduced.", "author_names": [ "Naoki Terao", "Toru Nakura", "Masahiro Ishida", "Rimon Ikeno", "Takashi Kusaka", "Tetsuya Iizuka", "Kunihiro Asada" ], "corpus_id": 13831408, "doc_id": "13831408", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Digitally Controlled Compensation Current Injection to ATE Power Supply for Emulation of Customer Environment", "venue": "J. Electron. Test.", "year": 2018 }, { "abstract": "We explore and demonstrate the extension of the synapse mimicking properties of memristive devices to a dysfunctional synapse as it occurs in the Alzheimer's disease (AD) pathology. The ability of memristive devices to reproduce synapse properties such as LTP, LTD, and STDP has been already widely demonstrated, and moreover, they were used for developing artificial neuron networks (perceptrons) able to simulate the information transmission in a cell network. However, a major progress would be to extend the common sense of neuromorphic device even to the case of dysfunction of natural synapses. Can memristors efficiently simulate them? We provide here evidences of the ability of emulating the dysfunctional synaptic behavior typical of the AD pathology with organic memristive devices considering the effect of the disease not only on a single synapse but also in the case of a neural network, composed by numerous synapses.", "author_names": [ "Silvia Battistoni", "Victor V Erokhin", "Salvatore Iannotta" ], "corpus_id": 13757520, "doc_id": "13757520", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Emulation with Organic Memristive Devices of Impairment of LTP Mechanism in Neurodegenerative Disease Pathology", "venue": "Neural plasticity", "year": 2017 }, { "abstract": "The design and development of a complex system requires an adequate methodology and efficient instrumental support in order to early detect and correct anomalies in the functional and non functional properties of the tested protocols. Among the various tools used to provide experimental support for such developments, network emulation relies on real time production of impairments on real traffic according to a communication model, either realistically or not. This paper aims at simply presenting to newcomers in network emulation (students, engineers, etc. basic principles and practices illustrated with a few commonly used tools. The motivation behind is to fill a gap in terms of introductory and pragmatic papers in this domain. The study particularly considers centralized approaches, allowing cheap and easy implementation in the context of research labs or industrial developments. In addition, an architectural model for emulation systems is proposed, defining three complementary levels, namely hardware, impairment, and model levels. With the help of this architectural framework, various existing tools are situated and described. Various approaches for modeling the emulation actions are studied, such as impairment based scenarios and virtual architectures, real time discrete simulation, and trace based systems. Those modeling approaches are described and compared in terms of services, and we study their ability to respond to various designer needs to assess when emulation is needed.", "author_names": [ "Emmanuel Lochin", "Tanguy Perennou", "Laurent Dairaine" ], "corpus_id": 3556196, "doc_id": "3556196", "n_citations": 24, "n_key_citations": 1, "score": 1, "title": "When should I use network emulation?", "venue": "Ann. des Telecommunications", "year": 2012 }, { "abstract": "Problem based learning (PBL) is a pedagogical method that challenges students to \"learn how to learn\" by working cooperatively in groups to develop solutions to real world problems. Network in a Box (NiB) is a unique, engineering oriented effort to employ PBL in core computer networks curriculum. Developed as an open ended exercise in PBL, NiB sets a learning environment in which student teams design and implement a network emulator using off the shelf hardware and open source software. The aims of this article are twofold. The first goal of this article is to catalogue our efforts at San Diego State University in implementing PBL in a computer networks engineering course. The second goal of this article is to introduce the NiB project as a viable example of PBL in the field of computer networks. This project not only arms students with a good understanding of network impairments but also provides the knowledge of low level packet processing, packet creation, packet injection into the network, meeting real time processing requirements of packet processing and packet filtering. By arming students with an understanding of network impairments, a working knowledge of low level packet processing, packet creation, packet injection, and their processing requirements, NiB serves as a model introduction of PBL into the field of computer networks engineering. In this article we disseminate the product specification and system design as an educational and research utility along with an assessment of this project as perceived by students over several semesters. (c) 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 433 446, 2011", "author_names": [ "Yusuf Ozturk" ], "corpus_id": 195703208, "doc_id": "195703208", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Network in a Box: Facilitating problem based learning through network emulation", "venue": "", "year": 2011 }, { "abstract": "In recent years, Deep Neural Networks have been increasingly adopted by a wide range of applications characterized by high reliability requirements, such as aerospace and automotive. In this paper, we propose an FPGA based platform for emulating faults in the architecture of DNNs. The approach exploits the reconfigurability of FPGAs to mimic faults affecting the hardware implementing DNNs. The platform allows the emulation of various kinds of fault models enabling the possibility to adapt to different types, devices, and architectures. In this work, a fault injection campaign has been performed on a convolutional layer of AlexNet, demonstrating the feasibility of the platform. Furthermore, the errors induced in the layer are analyzed with respect to the impact on the whole network inference classification.", "author_names": [ "Corrado De Sio", "Sarah Azimi", "Luca Sterpone" ], "corpus_id": 226847052, "doc_id": "226847052", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An Emulation Platform for Evaluating the Reliability of Deep Neural Networks", "venue": "2020 IEEE International Symposium on Defect and Fault Tolerance in VLSI and Nanotechnology Systems (DFT)", "year": 2020 }, { "abstract": "Code injection attacks against server and client applications have become the primary method of malware spreading. A promising approach for the detection of previously unknown code injection attacks at the network level, irrespective of the particular exploitation method used or the vulnerability being exploited, is to identify the malicious code that is part of the attack vector, also known as shellcode. Initial implementations of this approach attempt to identify the presence of shellcode in network inputs using detection algorithms based on static code analysis. However, static analysis cannot effectively handle malicious code that employs advanced obfuscation methods such as anti disassembly tricks or self modifying code, and thus these detection methods can be easily evaded. In this dissertation we present network level emulation, a generic code injection attack detection method based on dynamic code analysis using emulation. Our prototype attack detection system, called Nemu, uses a CPU emulator to dynamically analyze valid instruction sequences in the inspected traffic. Based on runtime behavioral heuristics, the system identifies inherent patterns exhibited during the execution of the shellcode, and thus can detect the presence of malicious code in arbitrary inputs. We have developed heuristics that cover the most widely used shellcode types, including self decrypting and non self contained polymorphic shellcode, plain or metamorphic shellcode, and memory scanning shellcode. Network level emulation does not rely on any exploit or vulnerability specific signatures, which allows the detection of previously unknown attacks. At the same time, the actual execution of the attack code on a CPU emulator makes the detector robust to evasion techniques like indirect jumps and self modifications. Furthermore, each input is inspected autonomously, which makes the approach effective against targeted attacks. Our experimental evaluation with publicly available shellcode construction engines, attack toolkits, and real attacks captured in the wild, shows that Nemu is more robust to obfuscation techniques compared to previous proposals, while it can effectively detect a broad range of different shellcode implementations without any prior exploit specific information. At the same time, extensive testing using benign generated and real data did not produce any false positives. To assess the effectiveness of our approach under realistic conditions we deployed Nemu in several production networks. Over the course of more than one year of continuous operation, Nemu detected more than 1.2 million attacks against real systems. We provide a thorough analysis of the captured attacks, focusing on the structure and operation of the shellcode, as well as the overall attack activity in relation to the different targeted services. The large and diverse set of the detected attacks combined with the zero false positive rate over the whole monitoring period demonstrate the effectiveness and practicality of our approach. Finally, we identify challenges faced by existing network trace anonymization schemes for safely sharing attack traces that contain self decrypting shellcode. To alleviate this problem, we present an anonymization method that identifies and properly sanitizes sensitive information contained in the encrypted part of the shellcode that is otherwise not exposed on the wire. Thesis Advisor: Prof. Evangelos Markatos", "author_names": [ "Michalis Polychronakis" ], "corpus_id": 63041549, "doc_id": "63041549", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Generic Detection of Code Injection Attacks using Network level Emulation", "venue": "", "year": 2009 }, { "abstract": "Western medicine (WM) has certain limitations in terms of treating acute cerebral infarction (ACI) while tonic traditional Chinese medicine injections (TCMIs) have been shown to have obvious clinical effects as an adjunct to WM for ACI. However, most randomized controlled trials (RCTs) to date have not performed direct comparisons of efficacy among tonic TCMIs. This study designed a Bayesian network meta analysis (NMA) to explore the therapeutic effect of tonic TCMIs on ACI. A comprehensive search of RCTs of TCMIs combined with WM for ACI was conducted using electronic databases for studies dated from the start date of each database until February 2020. Stata 13.0 and ADDIS 1.16.7 software were used to plot and analyze the data. Sixty six RCTs with a total of 5,989 patients involving 7 kinds of tonic TCMIs were included. Among TCMIs, Shenfu injection (SFI) WM ranked first in terms of improving clinical efficacy and the activities of daily living (ADLs) rating and reducing interleukin 6 (IL 6) and tumor necrosis factor a (TNF a) levels. While Ciwujia injection (CI) WM was the best choice for reducing neurological impairment and the high cut viscosity of whole blood (HCV) Shenmai injection (SI) WM had the greatest effects in terms of decreasing the levels of low cut viscosity of whole blood (LCV) fibrinogen (FIB) and plasma viscosity (PV) Based on the cluster analysis of the clinical efficacy and the neurological impairment, CI WM and Shenqifuzheng (SQI) WM were the best options for treating ACI. With respect to adverse drug reactions (ADRs) 35 RCTs did not monitor ADRs during treatment. In conclusion, tonic TCMIs could assist WM in benefiting patients with ACI. However, due to the limitations of the current study, strict monitoring of ADRs and data from high quality RCTs will be required in future to verify the advantage of TCMIs.", "author_names": [ "Dongrui Zhou", "Liandi Xie", "Yao Wang", "Shuang Wu", "Fengzhi Liu", "Shuangshuang Zhang", "Rui-jia Liu", "Lingqun Zhu" ], "corpus_id": 227754691, "doc_id": "227754691", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Clinical Efficacy of Tonic Traditional Chinese Medicine Injection on Acute Cerebral Infarction: A Bayesian Network Meta Analysis", "venue": "Evidence based complementary and alternative medicine eCAM", "year": 2020 }, { "abstract": "Water injection is one of the robust techniques to maintain the reservoir pressure and produce trapped oil from oil reservoirs and improve an oil recovery factor. However, incompatibility between injected water and reservoir water causes an unflavored issue named \"scale deposition.\" Owing to the deposited scales, effective permeability of a reservoir reduced, and pore throats might be plugged. To determine formation damage owing to scale deposition during a water injection process, two well known machine learning methods, least squares support vector machine (LSSVM) and artificial neural network (ANN) are employed in the present paper. To improve the performance of the LSSVM method, a metaheuristic optimization algorithm, genetic algorithm (GA) is used. The constructed LSSVM model is examined using real formation damage data samples experimentally measured, which was reported in the literature. According to the obtained outputs of the above models, LSSVM has a high performance based on the correlation coefficient, and infinitesimal uncertainty based on a relative error between the model predictions and the corresponding actual data samples was less than 15% Outcomes from this study indicate the useful application of the LSSVM approach in the prediction of permeability reduction due to scale deposition, and it can lead to a better and more reliable understanding of formation damage effects through water flooding without expensive laboratory measurements.", "author_names": [ "Mohammad Ali Ahmadi", "Zhangxin Chen" ], "corpus_id": 220305957, "doc_id": "220305957", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Machine learning based models for predicting permeability impairment due to scale deposition", "venue": "Journal of Petroleum Exploration and Production Technology", "year": 2020 }, { "abstract": "", "author_names": [ "Mikhael Polukhronakes" ], "corpus_id": 59712104, "doc_id": "59712104", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Generic detection of code injection attacks using network level emulation", "venue": "", "year": 2009 }, { "abstract": "Emulation of tactical wireless networks in a laboratory environment provides a cost effective solution for development tests and serves as a risk reduction for formal operational tests. However, laboratory based emulation of tactical Mobile Ad Hoc Networks (MANETs) is particularly challenging due to the complex nature of the underlying environment. Unlike point to point systems, emulation of MANETs requires the execution of multiple channels in parallel. Furthermore, tactical wireless channels are susceptible to impairments such as fading, Doppler, multipath, and jamming, which further complicates the ability to replicate such environments in a controlled laboratory setting. In this paper, we evaluate a previously developed Digital Wireless Channel Emulator (DWCE) by comparing field test results with data collected in an emulated environment for a 29 node tactical MANET. We present our approach for obtaining relevant metrics from the field and describe our methodology for comparison from both a qualitative and quantitative perspective.", "author_names": [ "Scott Buscemi", "Steven W Boyd" ], "corpus_id": 8782703, "doc_id": "8782703", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Comparative Analysis of Lab Based Network Emulation with Field Results for Large Scale MANETs", "venue": "2014 IEEE Military Communications Conference", "year": 2014 } ]

[ { "abstract": "Nanoscale two dimensional nanostructures have shown great potential as functional components in photocatalysis. Here, we report our investigations on the synthesis of heterostructured hybrids, comprised of 0D CdS nanoparticles as semiconductor and 2D/2D graphene/MoS x as co catalyst. Our approach involves a rapid microwave assisted reaction in autoclave conditions, by adopting either one step or two step protocol. The chemical speciation of the nanocomposites was found to depend strongly from the compounding conditions of the precursor substances. The photocatalytic activity was assessed by monitoring the photodegradation rate of 4 nitrophenol in solution, using simulated solar light irradiation. The photocatalytic activity of the hybrids may be attributed to a combination of beneficial characteristics, strongly related to the chemical speciation of the composite components. Moreover, intimate contacts of the latter result in efficient heterojunctions. Overall, the present study provides valuable insight regarding the development of functional heterostructured photocatalysts comprised of two dimensional nanomaterials.", "author_names": [ "Iordanis Tzanidis", "Feidias Bairamis", "L Sygellou", "Konstantinos S Andrikopoulos", "Apostolos Avgeropoulos", "Ioannis K Konstantinou", "Dimitrios Tasis" ], "corpus_id": 211111556, "doc_id": "211111556", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Rapid Microwave Assisted Synthesis of CdS/Graphene/MoSx Tunable Heterojunctions and Their Application in Photocatalysis.", "venue": "Chemistry", "year": 2020 }, { "abstract": "Abstract Inorganic organic hybrid materials, a class of probable candidates for combining two counterparts into one structure could be beneficial for improving or combing the excellent electronic, magnetic, rigidity and thermal stability, and optical feathers of inorganic frameworks with diverse structure, processability, flexibility and good geometric controllability of organic molecules. Anchoring inorganic organic hybrid materials with cocatalysts is a usually used strategy for enhancing their catalytic performance. However, noble metal cocatalysts always limit their practical application. Herein, we report that noble metal free cocatalyst of Ni2P decorated CdS diethylenetriamine (CdS DETA) can effectively overcome this limitation to achieve highly photocatalytic hydrogen production. The rapid microwave solvothermal synthesis of CdS DETA (MCdS DETA) process shortens reaction time, saves energy and lead to achieve highly photocatalytic activity due to its low crystallinity. When Ni2P decorated MCdS DETA, The 0.4%Ni2P/MCdS DETA exhibited the highest photocatalytic hydrogen evolution activity (6836 mmmol h 1 g 1) which is 4.14 times, 2.06 times and 1.34 times higher than traditional solvothermal CdS DETA(TCdS DETA) MCdS DETA and Pt cocatalysted MCdS DETA, respectively. The method reported here can be extended to other inorganic organic hybrid materials, and develops new strategies for exploring inorganic organic hybrid based photocatalysts.", "author_names": [ "Taiping Hu", "Kai Dai", "Jinfeng Zhang", "Guangping Zhu", "Changhao Liang" ], "corpus_id": 108722031, "doc_id": "108722031", "n_citations": 48, "n_key_citations": 0, "score": 0, "title": "Noble metal free Ni2P as cocatalyst decorated rapid microwave solvothermal synthesis of inorganic organic CdS DETA hybrids for enhanced photocatalytic hydrogen evolution", "venue": "Applied Surface Science", "year": 2019 }, { "abstract": "Abstract Structural analysis of Dy@CdS quantum dots (QDs) were investigated by the XRD and TEM/HRTEM. The particle size of Dy@CdS QDs was varies from 7.3 0.8 to 6.6 0.08 nm for 0.3% and 1.2% of Dy contents respectively. The vibrational spectra of pristine and Dy@CdS QDs exhibit the longitudinal phonon modes at 293 and 587 cm 1. Optical band gap of 2.5 eV was optimized at 0.6% Dy doped CdS sample and found to be decreased on further increasing the Dy3+ content from 0.9 to 1.2% The peaks at 414 and 466 nm are attributed to excitonic and trapped emission in the photoluminescence (PL) spectra of Dy@CdS samples respectively. The red shifts in PL spectra were observed for Dy3+ content more than 0.6% in Dy@CdS QDs. The frequency dependent characteristics of dielectric constant, dielectric loss, tangent and ac conductivity of Dy@CdS QDs were investigated at 300 K. It was founded that lower frequency range is dominated by the space charge polarization whereas orientational polarization is dominant at higher frequencies by increasing the dielectric constant. The variation of ac electrical conductivity was carried out linearly in the frequency range 15 kHz 10 MHz. The easy way of repeatability, tenability and scalability of Dy@CdS QDs are attributed for optoelectronics application.", "author_names": [ "Kamlesh V Chandekar", "Mohd Shkir", "Aslam Khan", "Salem AlFaify" ], "corpus_id": 219757631, "doc_id": "219757631", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "An in depth study on physical properties of facilely synthesized Dy@CdS NPs through microwave route for optoelectronic technology", "venue": "", "year": 2020 }, { "abstract": "The development of a highly efficient and rapid method for the accurate preparation of photocatalysts with novel morphologies is a hot research topic. The different morphologies of BiVO4 was prepared using surfactants assisted microwave method, and demonstrated irregular (no surfactant) octahedral (sodium dodecyl benzene sulfonate) olive like (polyvinylpyrrolidone) and hollow structures (ethylenediaminetetraacetic acid) respectively. The BiVO4 CdS were synthesized using the chemical bath deposition method with different morphologies of BiVO4 as the substrates. The hollow structure of BiVO4 displayed the highest photocatalytic performance. Moreover, the photodegradation rates of the hollow structure BiVO4 CdS on tetracycline hydrochloride and ciprofloxacin were about 1.8 and 1.5 times higher than the corresponding BiVO4, indicating that the Z scheme heterojunction can improve the photogenerated electron pairs separation efficiency. Furthermore, the regulation mechanism of morphology and energy band position, as produced using the surfactants, has also been thoroughly investigated in this work, which provides a novel insight into the efficient and rapid preparation of photocatalysts with special morphology and high performance.", "author_names": [ "Xiufang He", "Yunfeng Li", "Xia Yang", "Giancarlo Cravotto" ], "corpus_id": 210167060, "doc_id": "210167060", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Surfactants assisted preparation of BiVO4 with novel morphologies via microwave method and CdS decoration for enhanced photocatalytic properties.", "venue": "Journal of hazardous materials", "year": 2020 }, { "abstract": "Abstract In this work, we have prepared WO3 CdS nanocomposites for supercapacitor electrode by Microwave Assisted Method. The orthorhombic and monoclinic mixed structure of WO3 and hexagonal structure of CdS was observed by XRD pattern. The FESEM micrograph showed the irregular particle shape and HRTEM images demonstrated the small rod shape morphology with irregularity. The EDAX analysis confirmed the presence of W and Cd elements. From the electrochemical analysis, we have calculated the maximum capacitance as 650 F/g for WO3 CdS (6 wt% electrode. The long cycle test showed 133% of capacitance retention with 100% Coulombic efficiency.", "author_names": [ "Prakash Periasamy", "T Krishnakumar", "V P Devarajan", "Murugesan Sandhiya", "Marappan Sathish", "Murthy Chavali" ], "corpus_id": 219455932, "doc_id": "219455932", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Investigation of electrochemical supercapacitor performance of WO3 CdS nanocomposites in 1 M H2SO4 electrolyte prepared by microwave assisted method", "venue": "", "year": 2020 }, { "abstract": "Herein, we present the facile synthesis of different content of chromium (Cr) doped CdS quantum dots (Cr@CdS QDs) using microwave route within 15 min. The synthesized Cr@CdS QDs were investigated for structural, morphological, opto dielectric, and electrical natures. X ray diffraction confirms the monophasic hexagonal system of Cr@CdS and the sizes of crystallites are calculated to be 8.72, 7.04, 8.84, 6.56, 5.96, 6.52 and 6.99 nm for 0.0, 0.5, 1.0, 5.0, 10.0, 15.0, and 20.0 wt% Cr@CdS samples. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal the quantum dots size spherical shape morphology of synthesized Cr@CdS samples and the size is noted in range of 8.5 8.1 nm. The lattice spacing and orientation of grown QDs was also evaluated by high resolution TEM and Selected Area Electron Diffraction (SAED) pattern. Diffused reflectance spectra were recorded and Kubelka Munk theory is employed to estimate the energy gap. The energy gap was estimated between 2.4 and 2.46 eV for Cr@CdS QDs. Photoluminescence (PL) emission spectra own an strong emission peak in both spectra recorded at two different excitation wavelengths and revealed that the PL emission intensity is quenched with Cr doping in CdS. Dielectric and ac electrical studies shows the dependence on frequency and Cr content doping, and constant values are enhanced from 14 to 17 at 4 MHz. The prepared Cr@CdS QDs will be highly useful as sensitizers in solar cell, spintronics, and optoelectronics.", "author_names": [ "Mohd Shkir", "Ziaul Raza Khan", "Kamlesh V Chandekar", "Thamraa Alshahrani", "Ashwani Kumar", "Salem AlFaify" ], "corpus_id": 220481524, "doc_id": "220481524", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "A facile microwave synthesis of Cr doped CdS QDs and investigation of their physical properties for optoelectronic applications", "venue": "Applied Nanoscience", "year": 2020 }, { "abstract": "Abstract Semiconductor CdS/Multiwalled carbon nanotube quantum dots with crystallite size of 2 3 nm have been successfully synthesized by an ultrasound assisted microwave method. The sap of opunica ficus indica fruit is used as natural capping agent to enhance the quantum dot's stability. The synthesized CdS/MWCNTs QDs were characterized by XRD, UV Visible, FT IR, HR TEM, DLS, TGA, DTA and XRF. The photocatalytic activity of the QDs was tested for the degradation of dye, pararosaniline under simulated Ultra violet radiation. The degradation rate was found up to 99.19% within 150 Min. The influence of QDs as corrosion inhibition on zinc plate in three aerated electrolytes solutions namely NaCl, HCl and KOH was studied by Tafel polarization technique. The result showed that corrosion resistance succeeded due to CdS/MWCNTs QDs coating over Zn surface.", "author_names": [ "Kannan Kandasamy", "S Surendhiran", "Y A Syed Khadar", "Paramasivan Rajasingh" ], "corpus_id": 225425033, "doc_id": "225425033", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Ultrasound assisted microwave synthesis of CdS/MWCNTs QDs: A material for photocatalytic and corrosion inhibition activity", "venue": "", "year": 2020 }, { "abstract": "A novel reduced graphene oxide graphene CdS/CuS nanoplate (G CdS/CuS NP) was fabricated using a microwave method of loading CdS nanoplates onto graphene sheets (G CdS NP) and subsequent cation exchange between G CdS NP and Cu(NO3)2. The prepared G CdS/CuS NP exhibited excellent photocatalytic activity which was attributed to the synergy between graphene and CdS/CuS NP. The heterostructure in the CdS/CuS NP lead to an efficient charge transport across the interface. Graphene facilitated the transformation of electrons and reduced the recombination of electron hole pairs. These results provide a fabrication method for highly active photocatalysts and will lead to future rational design of photocatalytic materials.", "author_names": [ "Bin Zeng", "Wujun Zeng" ], "corpus_id": 201868595, "doc_id": "201868595", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Microwave Assisted Ion Exchange Synthesis and Enhanced Visible Light Photoactivity of Graphene CdS/CuS Nanoplates.", "venue": "Journal of nanoscience and nanotechnology", "year": 2020 }, { "abstract": "Semiconductor based heterojunction photocatalysts with a special active crystal surface act as an essential part in environmental remediation and renewable energy technologies. In this study, an RGO/CdS/TiO2 step scheme with high energy {001} TiO2 facets was successfully fabricated via a microwave assisted solvothermal method. The photocatalytic performance of as prepared samples was assessed by degrading methylene blue under visible light irradiation. We found that the photocatalytic activity of the RGO/CdS/TiO2 step scheme heterojunction was related to the proportion of TiO2. A ternary sample with a TiO2 content of 10 wt% exhibited superior photocatalytic performance, and approximately 99.7% of methylene blue was degraded during 50 min of visible illumination which was much higher than the percentages found for TiO2, CdS, RGO/TiO2, and RGO/CdS. The greatly improved photocatalytic performance is due to the exposure of the reactive {001} surface of TiO2 and the formation of a CdS/TiO2 heterojunction step scheme, which effectively inhibits the recombination of charge carriers at the heterogeneous interfaces. Moreover, the incorporation of graphene further enhances the visible light harvesting and serves as an electron transport channel for rapidly separating photogenerated carriers. Based on the PL, XPS, photoelectrochemical properties and the free radical capturing experiment results, a possible photodegradation mechanism was proposed.", "author_names": [ "Zilun Ma", "Li-yan Shi", "Wenwen Qu", "Qiong Hu", "Yijun Wang", "Zhen Chen" ], "corpus_id": 230609911, "doc_id": "230609911", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Microwave assisted synthesis of an RGO/CdS/TiO2 step scheme with exposed TiO2 {001} facets and enhanced visible photocatalytic activity", "venue": "", "year": 2020 }, { "abstract": "Hierarchical binary CdS/BiOCl heterostructures comprised of CdS nanoparticles (NPs) decorating on BiOCl nanoflakes (NFs) for the enhanced photocatalytic activity were fabricated by a facile two step microwave assisted aqueous chemical reaction. The chemical composition, morphology, crystal structure, and optical properties of the CdS/BiOCl nanostructures were characterized by various techniques. The results indicated that island like CdS NPs with 10 30 nm in size are planted on the surface of BiOCl NFs primarily exposed {001} facets with diameter in the range of 200 600 nm and thickness of about 30 nm. The possible growth mechanism for the satellite core structured hybrid CdS/BiOCl architectures was proposed. Particularly, CdS/BiOCl 3 exhibited the superior photocatalytic activity for the decomposition of Congo red in high concentration under visible light irradiation, in which the pseudo first order kinetic rate constant was 2.33, 8.32 and 2.06 times higher than that of pure CdS, pristine BiOCl and the physical mixture. The promotion mechanism could be ascribed to the perfect band matching and efficient internal charge transfer within the engineered heterojunction, resulting in the lower carrier recombination loss and the longer lifetime of electron hole pairs. Furthermore, the high photocatalytic performance for the degradation of malachite green and methyl red suggests a promising application in industrial wastewater purification.", "author_names": [ "Chonghai Deng", "Hanmei Hu", "Hong Yu", "Juanjuan Xu", "Mengyi Ci", "Yiping Wu", "Lili Wang", "Sane Zhu" ], "corpus_id": 225049271, "doc_id": "225049271", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Facile microwave assisted fabrication of CdS/BiOCl nanostructures with enhanced visible light driven photocatalytic activity", "venue": "Journal of Materials Science", "year": 2020 } ]

[ { "abstract": "The invention relates to an integrated circuit (IC) including, a flash memory device region, including a pair of split gate flash memory cells arranged over a semiconductor substrate. The pair of split gate flash memory cells respectively have a control gate (CG) including a polysilicon gate and an overlying silicide layer. A periphery circuit including, one or more high k metal gate (HKMG) transistors are arranged over the semiconductor substrate at a position laterally offset from the flash memory device region. The one or more HKMG transistors have a metal gate electrode with an upper surface that is lower than an upper surface of the silicide layer. A method of manufacturing the IC is also provided. The invention further relates to a structure and method to reduce polysilicon loss from flash memory devices during a replacement gate (RPG) process in integrated circuits.", "author_names": [ "" ], "corpus_id": 117234209, "doc_id": "117234209", "n_citations": 0, "n_key_citations": 0, "score": 2, "title": "Structure and method to reduce polysilicon loss from flash memory devices during replacement gate (RPG) process in integrated circuits", "venue": "", "year": 2015 }, { "abstract": "The impact of fluorine [F] amount generated from conventional WCVD process and ALD WCVD process on SONOS charge trapping 3D NAND memory are investigated. The damage degree of blocking oxide is an index for fluorine penetration through TiN/Al2O3 then further impacts the voltage break down (VBD) of ONO device characteristics. As compared to conventional WCVD process, ALD WCVD process with laminar 2D sequential growth can provide much better fill in performance at word line, less fluorine trap at grain boundaries, damage free of blocking oxide, minimal stress, and low resistance replacement gate to 3D NAND Flash.", "author_names": [ "Tuung Luoh", "YuKai Huang", "Chimin Chen", "Yung-Tai Hung", "Lin-Wuu Yang", "Tahone Yang", "Kuang-Chao Chen" ], "corpus_id": 215722629, "doc_id": "215722629", "n_citations": 0, "n_key_citations": 0, "score": 2, "title": "Tungsten Gate Replacement Process Optimization in 3D NAND Memory", "venue": "2019 Joint International Symposium on e Manufacturing Design Collaboration(eMDC) Semiconductor Manufacturing (ISSM)", "year": 2019 }, { "abstract": "Reduced multilayer graphene (rMLG) is investigated as a charge storage layer (CSL) in conventional floating gate (FG) flash memory structure. A large memory window of 9.4 V at 20 V program/erase and robust 10 years data retention at 150degC is demonstrated. Significant over erase observed in these memory devices signifies hole storage in the rMLG sheets. Fast programming and clear saturation of the program transients observed with the rMLG CSL memory devices suggest reduced ballistic transport in the plane perpendicular to the graphene. Activation energies for programmed and erased state retention losses are calculated as 1.05 and 1.11 eV, respectively. These observations establish the potential of rMLG sheets as a replacement of conventionally used polycrystalline silicon FG.", "author_names": [ "Abhishek Mishra", "A Janardanan", "Manali Khare", "Hemen Kalita", "Anil Kottantharayil" ], "corpus_id": 36666042, "doc_id": "36666042", "n_citations": 25, "n_key_citations": 3, "score": 0, "title": "Reduced Multilayer Graphene Oxide Floating Gate Flash Memory With Large Memory Window and Robust Retention Characteristics", "venue": "IEEE Electron Device Letters", "year": 2013 }, { "abstract": "By storing multibit per cell, multilevel cell (MLC) NAND flash memory achieves high storage capacity, but sacrificing data reliability. Error correction codes, such as Bose Chaudhuri Hocquenghem (BCH) codes, are widely used to ensure data reliability. However, high raw bit error rates induced by interference noises make BCH codes become insufficient to guarantee data reliability. Low density parity check (LDPC) codes are considered as the replacement due to the stronger error correction capability. Nevertheless, directly exploiting LDPC codes introduces a concern about decoding latency because of their iterative decoding in the soft decision process. To develop effective LDPC decoding algorithms, it is necessary to have a more profound understanding on flash failure patterns. This paper first observes the pair bit errors (PBEs) characteristic of MLC NAND flash memory on a real field programmable gate array testing platform, then proposes a PBE aware LDPC (PAL) decoding scheme based upon this observation, in which PBE provides the promotion information for LDPC decoding to reduce decoding latency. Simulation results show that the decoding latency can be reduced by up to 54% compared with the conventional LDPC codes.", "author_names": [ "Meng Zhang", "Fei Wu", "Yajuan Du", "Weihua Liu", "Changsheng Xie" ], "corpus_id": 56769117, "doc_id": "56769117", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Pair Bit Errors Aware LDPC Decoding in MLC NAND Flash Memory", "venue": "IEEE Transactions on Computer Aided Design of Integrated Circuits and Systems", "year": 2019 }, { "abstract": "Current bottleneck to the development of advanced 28nm and beyond nonvolatile memory is limited by the further scaling of existing flash memory, e.g. floating gate (FG) and SONOS, as a result of the scaling limit of the tunnel oxide as well as the retention issue. On the other hand, there is a strong demand to develop a memory cell which is compatible with the advanced logic HKMG CMOS generations for the embedded applications. In this talk, we will provide a solution on how to develop a replacement of FG and SONOS memories based on the resistive switching. This switching nonvolatile memory, named 1T NVM, comprises a simple MIM structure on the top of the transistor gate while the readout is taken from the transistor Vth or Id, similar to that of flash memory. A bilayer MIM is preferable for quality performance. Experimental results demonstrated that this memory exhibits good endurance, retention, and can solve the sneak path, forming issues in conventional crossbar ReRAM. The architecture of this basic NVM is especially useful for the embedded design in high k metal gate logic CMOS with 28nm and beyond. It has great potential for both NOR and NAND memory, and in particular for embedded applications.", "author_names": [ "S Chung" ], "corpus_id": 195223449, "doc_id": "195223449", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Embedded Resistive Switching Non Volatile Memory Technology for 28nm and Beyond High k Metal Gate Generations", "venue": "2019 IEEE 11th International Memory Workshop (IMW)", "year": 2019 }, { "abstract": "Summary form only given. In this work we investigated vertical flash memory devices with Al2O3 as control oxide with protein mediated self assembled PbSe nanocrystals used as floating gate. The introduction of high k dielectric as control oxide provides lower voltage/faster operation and hence less power consumption compared with the devices fabricated with SiO2 as control oxide. For appropriate memory operation the dielectric permittivity, conduction/valence band offset and thickness of the high k material have to be properly engineered. Higher permittivity ensures better capacitance and scalability; higher band offset improves retention and programming window. Al2O3 has the potential to be the high k replacement of inter poly oxide due to its relatively high electron and hole barrier heights and high permittivity.", "author_names": [ "Fahmida Ferdousi", "J Sarkar", "S Tang", "Davood Shahrjerdi", "Tank Akyol", "Joseph Patrick Donnelly", "Emanuel Tutuc", "S K Banerjee" ], "corpus_id": 27926584, "doc_id": "27926584", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Vertical Flash memory devices with Protein assembled Nanocrystal floating gate and A12O3 control oxide", "venue": "2008 Device Research Conference", "year": 2008 }, { "abstract": "The nitride based SONOS cell, for its excellent scalability and process simplicity, is the candidate to push the scaling roadmap for FLASH memories beyond the limit imposed on floating gate memories by the electrostatic interference between adjacent cells. The traditional SONOS cell consists of a nitride layer (the storage element) encapsulated by two SiO2 layers which isolate the nitride layer from the Si substrate and the poly Si gate (Poly Si/SiO2/Si3N4/SiO2/c Si) However, the thick tunnel oxide necessary to meet the retention requirements imposes a severe limit on the erase performance because of the erase saturation phenomenon. One possibility to guarantee both the erase and the retention performance is the replacement of the top SiO2 layer with materials of higher dielectric constant (high k dielectric) The presence of a high k dielectric reduces the electric field across the top dielectric, thus decreasing the unwanted parasitic electron injection from the gate during the erase operation. This will allow the cell to erase deep so to meet a basic requirement for Gigabit multilevel NAND memories. The introduction of high k materials in the SONOS stack is unfortunately not straightforward. One problem is the Fermi level pinning at the poly Si/high k interface. Another problem is the morphological changes the high k material undergoes during the device fabrication thermal budget. These changes can modify the k value and affect the band offset between gate and high k material. The results may, in both cases, be the decrease of the barrier for electron injection from the gate and, as a consequence, the deterioration of the erase performance. In this paper we study the effect of gate material and of the morphological transformation associated with the high k post deposition anneal on the erase and the retention behaviour of nitride based cells. Two different high k dielectrics are investigated: Al2O3 (which has already been found to be able to significantly improve the erase operation, guaranteeing at the same time excellent endurance and sufficient bake retention) and HfAlO. We show that both for Al2O3 and HfAlO a trade off exists between erase and retention, higher PDA temperatures being beneficial for erase but detrimental for retention. We also discuss the effect of Fermi level pinning and poly Si depletion on the erase behaviour and compare the erase performances of several PVD and AVD deposited metal gates.", "author_names": [ "Antonio Cacciato", "Laurent Breuil", "Geert Van den Bosch", "Olivier Richard", "A Rothschild", "Arnaud Furnemont", "Hugo Bender", "Jorge A Kittl", "Jan Van Houdt" ], "corpus_id": 101247871, "doc_id": "101247871", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effect of Top Dielectric Morphology and Gate Material on the Performance of Nitride based FLASH Memory Cells", "venue": "", "year": 2008 }, { "abstract": "In this paper, we have investigated the effect of rare earth materials in tunnel dielectric to improve the trade off between erase speed and retention. Here, rare earth materials have low valence band offset with high permittivity to enhance both erase speed and retention in bandgap engineered silicon oxide nitride oxide silicon (BE SONOS) In addition, we observed higher program speed due to lower conduction band offset as compared to SiO2. Silicate of scandate of rare earth element, GdScSiO (Gd=Gadolinium) is investigated as SiN replacement in tunnel dielectric (SiO2/SiN/SiO2) of BE SONOS. Further, rare earth aluminates, GdAlO and LuAlO (Lu=Lutetium) are used to replace the SiO2 layer in tunnel oxide. Also, gate length is scaled down and we have observed the effect of aforementioned materials in tunnel barrier, however, for the same effective oxide thickness (EOT) We found that the scaling down of gate length has negligible impact on the reliability of the devices. As a consequence, various investigated tunnel oxide stacks possess good memory characteristics with a negligible charge loss (at 25 degC) after a period of ten years and a considerable charge loss at an elevated temperature of 150 degC.", "author_names": [ "Mansimran Kaur", "Deepika Gupta", "Vikas Vijayvargiya", "Santosh Kumar Vishvakarma", "Vaibhav Neema" ], "corpus_id": 36286657, "doc_id": "36286657", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Characterization of BE SONOS flash memory using rare earth materials in tunnel barrier with improved memory dynamics", "venue": "2015 IEEE Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia)", "year": 2015 }, { "abstract": "Abstract Flash memories are now widely used in many portable electronic devices, in embedded systems and are even as replacement for computer hard disks. In flash memory systems, high voltages (up to about 10 V) are indispensable for programming operations. In many cases, however, such programming voltages are not directly available from the supply, and are usually generated by embedded voltage converting or charge pumping circuits. These circuits produce the required programming voltage from available external supplies with voltages in the approximate range of 1 5 V. The power conversion efficiency, the chip size, the voltage regulation, as well as the loading characteristics have been the major concerns for such circuits. The present paper discusses some recently proposed charge pumping circuits for flash memory applications. We focus on the effects of the dynamic gate control, the 4 phase gate boosting and cross coupled configuration for enhancing the performance of the charge pump circuits. Several different charge pumps operated under different working conditions are then investigated in detail.", "author_names": [ "Oi-Ying Wong", "Hei Wong", "Wing-Shan Tam", "C W Kok" ], "corpus_id": 10400518, "doc_id": "10400518", "n_citations": 24, "n_key_citations": 1, "score": 0, "title": "A comparative study of charge pumping circuits for flash memory applications", "venue": "Microelectron. Reliab.", "year": 2012 }, { "abstract": "This paper describes the novel process/device technology for high speed sub halfmicron flash memories with 0.4 /spl mu/m design rules. Some new structures and operating methods for future flash memories have been proposed. However, the most suitable structure to realize large memory capacity for magnetic disk replacement will be different from that for fast random access speed for EPROM replacement, flash memory embedded logic devices, and other high speed applications. To realize high speed random access operation, conventional NOR type flash memory technology with CHE program and source erase scheme will be the most suitable because of its simple fabrication process, relatively small cell size, sufficiently high read current, and relatively low operation voltages for program and erase procedures. The low voltage program/erase operation results in high performance peripheral transistors. On the other hand, NAND flash EEPROM will be the most suitable for low cost large memory capacity applications. This paper, for the first time, demonstrates the scalability of cell gate length down to 0.4 /spl mu/m for simple stacked gate NOR flash cell.<ETX>", "author_names": [ "Seiichi Mori", "Eiji Sakagami", "Yuichiro Yamaguchi", "Eiji Kamiya", "Masao Tanimoto", "Hiroaki Tsunoda", "Kohei Hisatomi", "H Egawa", "N Arai", "Y Hiura", "Kuniyoshi Yoshikawa", "Koji Hashimoto" ], "corpus_id": 62348513, "doc_id": "62348513", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "High speed sub halfmicron flash memory technology with simple stacked gate structure cell", "venue": "Proceedings of 1994 VLSI Technology Symposium", "year": 1994 } ]

[ { "abstract": "Piezoelectric semiconductor based piezocatalysis has emerged as a promising approach for converting mechanical energy into chemical energy for renewable hydrogen generation and wastewater treatment under the action of mechanical vibration. Similar to photocatalysis, piezocatalysis is triggered by the separation, transfer, and consumption of piezo generated electrons and holes. Inspired by this, herein, we report that the cocatalyst, which is widely used in photocatalysis, can also improve the semiconductor based piezocatalytic properties. In the proof of concept design, well defined Pd as a model cocatalyst has been deposited on the surface of piezoelectric BiFeO3 nanosheets, which not only facilitates the separation of charge carriers by accepting the piezoelectrons from BiFeO3 but also lowers the activation energy/overpotential through supplying highly active sites for the proton reduction reaction. Consequently, the as obtained hybrid piezocatalyst delivers a high H2 evolution rate of 11.4 mmol h 1 (10 mg of catalyst) 19.0 times as high as that of bare BiFeO3. The band tilting induced by the piezoelectric potential is proposed to lower or eliminate the Schottky barrier and smooth the electron transfer from BiFeO3 to Pd, while the exposed facet, domain size, and loading amount of Pd cocatalyst are proved to be the key parameters determining the ultimate piezocatalytic activity. Our work provides some enlightenment on advancing the design and fabrication of more efficient piezocatalysts for H2 evolution based on rational engineering on the cocatalyst.", "author_names": [ "Guodong Yang", "Weijun Wang", "Shijie Wu", "Binjia Gao", "Yanbo Xu", "Zheng Chen", "Shuxian Zhong", "Jianrong Chen", "Song Bai" ], "corpus_id": 232406951, "doc_id": "232406951", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Cocatalyst Engineering in Piezocatalysis: A Promising Strategy for Boosting Hydrogen Evolution.", "venue": "ACS applied materials interfaces", "year": 2021 }, { "abstract": "Piezocatalysis, converting mechanical vibration into chemical energy, is an emerging technology to address environmental issues. In this work, we propose an efficient method to significantly improve the piezocatalytic activity by morphology engineering rather than composition design. The catalytic property in BaTiO3 nanocrystallites with diverse morphologies is investigated by dye degradation and hydrogen production under ultrasonic vibration. The BaTiO3 nanosheets exhibit an excellent piezocatalytic activity with a degradation rate of 0.1279 min 1 for Rhodamine B, far beyond those in previous piezocatalytic literature and even comparable to excellent photocatalysts, and also a high hydrogen production rate of 92 mmol g 1 h 1. Compared with nanowires and nanoparticles, the 2D morphology greatly enhances the piezocatalytic activity in nanosheets owing to much larger piezoelectric potential. This proves that the piezocatalytic property is dominated by the morphology dependent piezoelectricity, rather than specific surface area as other catalysis. Dominated by bending vibrating mode, the piezocatalytic activity reaches a maximum at the piezoelectric resonating frequency, and it increases with the ultrasonic power. Moreover, it has good reusability and wide versatility for catalytic degradation. This work gives an in depth understanding of piezocatalytic mechanism and provides a way to develop high performance and eco friendly piezocatalysts.", "author_names": [ "Chengye Yu", "Meng Xi Tan", "Chuanbao Liu", "Ruowei Yin", "Hui-min Meng", "Yanjing Su", "Lijie Qiao", "Yang Bai" ], "corpus_id": 233211769, "doc_id": "233211769", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Ultrahigh piezocatalytic capability in eco friendly BaTiO3 nanosheets promoted by 2D morphology engineering.", "venue": "Journal of colloid and interface science", "year": 2021 }, { "abstract": "Abstract The polarization field with the function in carrier separation has aroused substantial interest. For heterojunction complexes, however, the static polarization field will be inevitably shielded by a large number of carriers. Herein, a novel hybrid consisted of single domain PbTiO3 coated by CdS particles was selected as a model material to prove that the alternating piezoelectric field induced by periodic stress can destroy shielding effect. After the introduction of alternating piezoelectric potential by using ultrasonication, PbTiO3/CdS 10 exhibited a much higher H2 production rate by piezo photocatalysis (849.0 mmol h 1 g 1) than by individual piezocatalysis (400.6 mmol h 1 g 1) or photocatalysis (98.9 mmol h 1 g 1) Furthermore, the finite element simulation shows that PbTiO3/CdS heterostructure has a superior piezoelectric potential difference compare to pure PbTiO3 or pure CdS. Based on data analysis, the mechanism about the piezo photo coupling effect was proposed, which will provide a reference for the design and development of high efficiency piezo photocatalyst.", "author_names": [ "Xueyan Huang", "Rui Lei", "Jie Yuan", "Fan Gao", "Cankun Jiang", "Wenhui Feng", "Jiandong Zhuang", "Ping Liu" ], "corpus_id": 224928610, "doc_id": "224928610", "n_citations": 16, "n_key_citations": 0, "score": 1, "title": "Insight into the piezo photo coupling effect of PbTiO3/CdS composites for piezo photocatalytic hydrogen production", "venue": "", "year": 2021 }, { "abstract": "Piezocatalysis is a promising approach for environmental pollutant removal. Monoclinic dibismuth tetraoxide (m Bi2O4) was first applied to piezocatalyze organics under ultrasonic vibration. The built in electric field with ultrasonic stress drives the separation of holes and electrons in m Bi2O4. Its excellent piezocatalytic activity, reusability and chemical stability make m Bi2O4 a new candidate of piezocatalysis.", "author_names": [ "Fengling Liu", "Haoxuan Chen", "Chenmin Xu", "Linlin Wang", "Pengxiang Qiu", "Shuo Gao", "Jiawei Zhu", "Shuai Zhang", "Zhaobing Guo" ], "corpus_id": 231943596, "doc_id": "231943596", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Monoclinic dibismuth tetraoxide (m Bi2O4) for piezocatalysis: new use for neglected materials.", "venue": "Chemical communications", "year": 2021 }, { "abstract": "Piezocatalysis provides a promising strategy for directly converting weak mechanical energy into chemical energy. In this work, we report a simple one step hydrogen reduction route for the simultaneous generation of surface defects and heterojunctions in Sr0.5Ba0.5Nb2O6 nanorods fabricated by a molten salt synthesis method. The as fabricated Sr0.5Ba0.5Nb2O6/Sr2Nb2O7 nanocomposites with controllable oxygen vacancies exhibited excellent piezocatalytic activity under ultrasonic vibration, with an about 7 times enhancement of the rate constant (k 0.0395 min 1) for rhodamine B degradation and an about 10 times enhancement of the water splitting efficiency for hydrogen generation (109.4 mmol g 1 h 1) for the optimized sample (H2 annealed at 500 degC) compared to pristine Sr0.5Ba0.5Nb2O6 nanorods. This work demonstrates the essential role of a well modulated oxygen vacancy concentration in the piezocatalytic activity and provides an inspiring guide for designing self generated heterojunction piezocatalysts.", "author_names": [ "Jianqing Dai", "Ningning Shao", "Suwei Zhang", "Zhicheng Zhao", "Yangke Long", "Shiyin Zhao", "Shun Li", "Cui-hua Zhao", "Zuotai Zhang", "Weishu Liu" ], "corpus_id": 231819808, "doc_id": "231819808", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Enhanced Piezocatalytic Activity of Sr0.5Ba0.5Nb2O6 Nanostructures by Engineering Surface Oxygen Vacancies and Self Generated Heterojunctions.", "venue": "ACS applied materials interfaces", "year": 2021 }, { "abstract": "Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZTO) ferroelectric ceramic loaded with Ag nanoparticles (NPs) was explored for its photo/piezocatalytic performance. The presence of Ag loading on BCZTO ceramic was confirmed using electron microscopes. X ray photoelectron spectroscopy revealed the metallic chemical state of Ag NPs loaded on the surface of BCZTO ceramic. The absorbance spectrum of the Ag loaded BCZTO sample showed a visible light absorption hump due to the phenomenon of surface plasmonic resonance. During the photocatalysis process, the [Formula: see text]99% of rhodamine B (RB) dye was degraded in aqueous solution using the Ag loaded BCZTO sample, showing its promising photocatalysis activity. During the piezocatalysis process, the [Formula: see text]95% of RB dye was degraded using the Ag loaded BCZTO sample, showing its promising piezocatalytic activity. The *OH radical species were found responsible for the photocatalytic and piezocatalytic performance. The photo/piezocatalytic performance was found to be consistent over five cycles, indicating promising reusability of the Ag loaded BCZTO sample.", "author_names": [ "Moolchand Sharma", "Gurpreet J Singh", "Rahul Vaish" ], "corpus_id": 231643314, "doc_id": "231643314", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Ag nanoparticles loaded Ba0.85Ca0.15Ti0.9Zr0.1O3 for multicatalytic dye degradation.", "venue": "Nanotechnology", "year": 2021 }, { "abstract": "Abstract The cascading of methane valorization and methanol upgrade, both of which are important in C1 chemistry, becomes a promising strategy to fabricate value added chemicals from methane directly. Reconciling the contradiction between the C H bond activation of methane and the over oxidation susceptibility of methanol is critical but challenging. Herein, we report the piezocatalytic methane conversion over hydroxyapatite (HAp) under ultrasonic vibration at ambient conditions, obtaining alcohols as liquid products without any sign of CO or CO2. Mechanistic studies reveal that the piezocatalytic effect of HAp drives H2O and methane activation and supplies hydroxyl radical *OH) to attack the methane C H bond, while the ultrasonic induced negative surface charge (SC) promotes methanol dehydration into methyl carbene as a fascinating C1 building block to facilitate product upgrade into C2 and C3 alcohols. Attributing to the enriched SC which tunes the surface acid base property, piezocatalysis presents a new approach for C C coupling.", "author_names": [ "Yuanyi Zhou", "Haipeng Wang", "Xuechen Liu", "Simeng Qiao", "Dengkui Shao", "Jing Zhou", "Longyan Zhang", "Wenzhong Wang" ], "corpus_id": 225131761, "doc_id": "225131761", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Direct piezocatalytic conversion of methane into alcohols over hydroxyapatite", "venue": "", "year": 2021 }, { "abstract": "Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCZTO) ferroelectric ceramic loaded with Ag nanoparticles (NPs) was explored for its photo/piezocatalytic performance. The presence of Ag loading on BCZTO ceramic was confirmed using electron microscopes. X ray photoelectron spectroscopy revealed the metallic chemical state of Ag NPs loaded on the surface of BCZTO ceramic. The absorbance spectrum of the Ag loaded BCZTO sample showed a visible light absorption hump due to the phenomenon of surface plasmonic resonance. During the photocatalysis process, the 99% of rhodamine B (RB) dye was degraded in aqueous solution using the Ag loaded BCZTO sample, showing its promising photocatalysis activity. During the piezocatalysis process, the 95% of RB dye was degraded using the Ag loaded BCZTO sample, showing its promising piezocatalytic activity. The *OH radical species were found responsible for the photocatalytic and piezocatalytic performance. The photo/piezocatalytic performance was found to be consistent over five cycles, indicating promising reusability of the Ag loaded BCZTO sample.", "author_names": [ "Moolchand Sharma", "Gurpreet J Singh", "Rahul Vaish" ], "corpus_id": 229688540, "doc_id": "229688540", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Ag nanoparticles loaded Ba0.85Ca0.15Ti0.9Zr0.1O3 for multicatalytic dye degradation", "venue": "Nanotechnology", "year": 2020 }, { "abstract": "Abatract Photocatalysis technology has been proved to be a potential strategy for removal of organic dyes, however high power light sources are generally necessary to initiate photocatalytic reaction. In this work, we employed an excellent photocatalyst of Bi2WO6 with visible light harvest and meanwhile an intrinsic ferroelectricity, which realized the efficient degradation of organic dye via the synergetic photopiezocatalysis. Through coupling the illumination by a low power (9 W) LED and the ultrasonic vibration (120 W) by an ultrasonic cleaner, the nanoflower like Bi2WO6 composed of ultrathin nanosheets showed a much more enhanced photopiezocatalysis performance for purification of organic dye than the individual photocatalysis and piezocatalysis. Furthermore, the high mineralization efficiency and the good durability of the Bi2WO6 catalyst were demonstrated. The possible mechanism of photopiezocatalysis was finally proposed, where the ultrasound induced piezoelectric field in Bi2WO6 drove photo generated electrons and holes to diffuse along opposite directions, consequently promoting the separation efficiency of charge carriers. This work indicates that the synergetic photopiezocatalysis by coupling irradiation and ultrasonic vibration is a promising strategy to purify organic pollutants in wastewater.", "author_names": [ "Hua Lei", "Meixuan Wu", "Y Liu", "Fan Mo", "Jiayao Chen", "Shilong Ji", "Yan Zou", "Xiaoping Dong" ], "corpus_id": 230573725, "doc_id": "230573725", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Built in piezoelectric field improved photocatalytic performance of nanoflower like Bi2WO6 using low power white LEDs", "venue": "Chinese Chemical Letters", "year": 2021 }, { "abstract": "Abstract Excellent vibration electricity conversion in various piezoelectric materials is frequently restricted, thus hardly generates high mechanochemical potential eliciting by ferroelectric polarization for advanced catalysis processes. Herein, we propose a phase boundary in Li modified Na0.5K0.5NbO3 (NKN) materials to improve the piezocatalytic activity, and the relationships among the composition, phase structure, electrochemical and catalytic performances were systematically investigated. An outstanding piezocatalytic performance was exhibited in the LNKN6 (6 mol Li doped NKN) with coexistence of orthorhombic and tetragonal phases, and the piezocatalytic activity showed a superior repeatability and universal applicability for the degradation of organic pollutants. The reaction rate constant of the LNKN6 was up to 25.16 x 10 3 min 1, which was 3.20 times than that of pristine NKN. The enhancement of piezocatalytic activity was confirmed by Landau Ginsburg Devonshire phenomenological theory and the transfer efficiency of force generated electrons and holes, and then an appropriate mechanism of the ultrasonic vibration driven piezocatalysis was speculated. This work provides an alternative strategy to enhance the catalytic efficiency of piezocatalyst and the high activity of the NKN based piezoelectrics has an important application for environmental remediation.", "author_names": [ "An Shan Zhang", "Zhiyong Liu", "Bing Xie", "Jinshan Lu", "Kun Guo", "Shanming Ke", "Longlong Shu", "Huiqing Fan" ], "corpus_id": 225026410, "doc_id": "225026410", "n_citations": 16, "n_key_citations": 0, "score": 1, "title": "Vibration catalysis of eco friendly Na0.5K0.5NbO3 based piezoelectric: An efficient phase boundary catalyst", "venue": "", "year": 2020 } ]

[ { "abstract": "Recent trends and progresses in power electronics rely on fast, miniaturized, high current and high temperature switching semiconductors. However, in electronics system design, passive components technologies, in particular capacitors, limit their full exploitation. The goal of the present paper is, firstly, to analyse the capacitor technologies, in particular ceramic technologies for the limits set by high current, high voltages, high temperatures, high frequencies, and by cost items. Secondly, for each of the identified limits, to define the tools and technologies that are capable to overcome it. The new technologies include a new PLZT based antiferroelectric ceramic material with high switching field, copper inner electrode for the multilayer construction, firing in reducing atmosphere, applying a sputter method for the outer connecting electrode combined with silver sintering of a flexible termination or of a pressfit connector. The third goal is to show how the new technologies are applied such that", "author_names": [ "Guenter Engel" ], "corpus_id": 113042872, "doc_id": "113042872", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Material Requirements for Power and High Temperature Multilayer Ceramic Capacitors (MLCC)", "venue": "", "year": 2015 }, { "abstract": "Microstructure of termination of a base metal electrode multilayer ceramic capacitor (BME MLCC) using copper nickel bimetallic powder as electrode material was investigated. Thick film paste containing nonagglomerated monodispersed copper nickel bimetallic powder was applied in preparing the termination electrode of a BME MLCC. Influence of an inorganic binder on the microstructure of the termination of BME MLCC was studied. The distribution of metallic copper on the surface of glass bubbles in termination was investigated by energy dispersive X ray. A scanning electron microscope and a polarized light microscope were applied to discuss the microstructure of thick film. The results show that suitable binder and firing temperature result in the excellent connection between internal and termination electrode, as well as one between termination electrode and green chip. The BME MLCCs with a dense surface of end termination, high adhesion, and qualified electrical behavior were obtained. The rough interface from interfacial reaction between glass and chip gives high adhesion", "author_names": [ "Wu Songping" ], "corpus_id": 24395905, "doc_id": "24395905", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Termination of BME MLCC Using Copper Nickel Bimetallic Powder as Electrode Material", "venue": "IEEE Transactions on Components and Packaging Technologies", "year": 2006 }, { "abstract": "The copper paste for termination electrode of BME MLCC is composed of organic vehicle,glass frit,copper powder and others.The termination electrodes are formed after dipping,drying and terminal firing.Results of experiments indicate that copper paste for BME MLCC has high adhesion and low DF,and is well fit for BME MLCC.", "author_names": [ "Jin Fu-zhen" ], "corpus_id": 137717995, "doc_id": "137717995", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research of Copper Termination Paste for BME MLCC", "venue": "", "year": 2006 }, { "abstract": "Conventional copper powder used to form terminations of MLCC generally contains large flakes with high aspect ratios and large agglomerate spherical particles. The use of agglomerate powder and large flakes results in low dry film density, and thus a thicker film. In our research, we focused on highly dispersed, uniform, and fine flakes and powder that did not contain coarse particles, and examined the paste characteristics and their effect on firing conditions. We found that a smaller particle size would increase the thixotropic value and result in an earlier start to firing. We also discovered that the agglomerate condition of powder had a significant influence on the rheology of the paste. A higher degree of agglomeration would result in higher viscosity and a higher thixotropic value, but would not have a major effect on the firing condition.", "author_names": [ "Takahiko Sakaue", "Katsuhiko Yoshimaru" ], "corpus_id": 137432474, "doc_id": "137432474", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Copper Powder for Termination Electrode in MLCC", "venue": "", "year": 2003 }, { "abstract": "Abstract In this paper, non agglomerated monodispersed ultra fine copper metallic powders have been synthesized with chemical reduction method. Fine lead free glass powders were also prepared by solid synthesis process. Thick film paste prepared by above mentioned copper metallic powders and lead free glass powders was applied as conductive paste of MLCC. Mixture of glass and zinc oxide give the thick film a high adhesion strength which is attributed to the rough interface from interfacial reaction between glass and chip, and a good densification. Diffusion of metal between copper thick film and nickel thick film is clear. Ni Cu solid solution appears under high temperature firing.", "author_names": [ "Songping Wu" ], "corpus_id": 136375767, "doc_id": "136375767", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Preparation of ultra fine copper powder and its lead free conductive thick film", "venue": "", "year": 2007 }, { "abstract": "Direct bonded copper (DBC) also called the gas metal eutectic bonding method, is an important substrate material commonly used for thermal and electrical management in power modules. Developed almost 40 years ago by General Electric, there is wide use of this structure when there is a need of a substrate with high current carrying and high thermal conductive abilities. The components of DBC are a ceramic (usually Aluminum Oxide (Al2O3, also called \"alumina\" and a bonded piece of copper on one or both sides. This copper is strongly bonded to the alumina, giving strong adhesion and combining benefits from both materials. This paper will give a summary of DBC technology and will discuss the role that furnace temperature and atmosphere perform during processing. Introduction The development of DBC has pushed boundaries of power electronic applications. It is used in such products as concentrated photovoltaics and semiconductor modules for automotive applications [1] The value of DBC comes from its high thermal conductivity due to copper and its low coefficient of thermal expansion as a result of ceramic. The need for low thermal expansion is so that solder on silicon semiconductors won't be damaged with heat cycling. For DBC ceramics, alumina (Al2O3) is commonly used, but other ceramics such as aluminum nitride (AlN) or Beryllium Oxide (BeO) are also utilized in bonding. Alumina is preferred because of its low cost and efficiency compared to these other ceramics, and DBC is chosen over other bonding processes because there is no need for intermediary layers in the process. According to Burgess et al. Al. MgO, SiO2, and CaO are intermediary layers located at the grain boundaries of the ceramic. This layer penetrates into the porous layer of the metal at sintering temperatures and locks the metal into the ceramic. DBC is preferred because intermediary layers often have problems with current flows at the metal ceramic interface and are less corrosion resistant, leading to early failure. DBC begins with layering of copper onto alumina as seen in Figure 1. The contact interface between the copper and the alumina is the most important area of processing. Copper exhibits a wetting behavior on alumina that covers the area of contact during firing. With a temperature range between 1065o C and 1083o C, interface adhesion occurs. With research and developments in DBC technology, production is possible on a larger scale using equipment such as the belt furnace. Controlling furnace conditions is important in reaching the high eutectic temperature that is needed to begin the bonding process while staying below the melt temperature of copper. Specific controls of the furnace atmosphere are needed as well during processing.", "author_names": [], "corpus_id": 53462501, "doc_id": "53462501", "n_citations": 1, "n_key_citations": 1, "score": 1, "title": "Influence of Firing Temperature and Atmospheric Conditions on the Processing of Directly Bonded Copper DBC", "venue": "", "year": 2017 }, { "abstract": ".iii LIST OF FIGURES .vi LIST OF TABLES .xii ACKNOWLEDGMENTS .xiii CHAPTER 1 GENERAL INTRODUCTION .1 1.1 Applications: Multilayer Ceramic Capacitors (MLCCs) .1 1.2 Background: Perovskite Structure. .3 1.3 Background: Ferroelectricity .5 1.3.1 Relaxor Ferroelectrics .6 1.4 (1 x)BaTiO3 xBi(M)O3 Dielectrics .7 1.5 Cofiring BaTiO3 Bi(Zn1/2Ti1/2)O3 with Electrodes .9 1.5.1 Proposed Solution to Thermodynamic Challenges .10 1.5.2 Additional Challenge: Lowering the Dielectric Sintering Temperature .12 1.6 Thesis Organization .13 CHAPTER 2 CURRENT UNDERSTANDING OF STRUCTUREPROCESSING PROPERTY RELATIONSHIPS IN BaTiO3 Bi(M)O3 DIELECTRICS .16 2.", "author_names": [ "Michaela A Beuerlein" ], "corpus_id": 146219773, "doc_id": "146219773", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Phase Formation, Microstructure Development, and Copper Co Firing of Barium Titanate Bismuth Zinc Titanate and Related Dielectrics", "venue": "", "year": 2017 }, { "abstract": "Small arms firing ranges are an important source of metal contaminants in the ecosystems located near these facilities, owing to the constant fall and alteration of the ammunition remnants on the soil, particularly in nearby berms. The objectives of this study were to analyse the pollution of chromium (Cr) copper (Cu) nickel (Ni) lead (Pb) and zinc (Zn) in rifle/pistol shooting range soils, to estimate their availability and to evaluate the influence of the ammunition used. The concentrations of Pb, Zn, Cu, Cr and Ni range from 55 to 6*309, 34 to 264, 19 to 98, 40 to 79 and 11 to 33 mg kg 1, respectively. The moderate acidity and organic matter content favour the availability of Pb, followed by Cu Zn Ni Cr. The values of different contamination indexes (Igeo, pollution index and integrated pollution index) suggest that Pb soil contamination is moderate to heavy, especially in the berm area and moderate for Cu and Zn. Lead ammunition is the main source of pollution, but another one was identified owing to the concentrations of Fe, Cr and Ni detected. Further studies are needed to verify their long term potential adverse effects. Copyright (c) 2016 John Wiley Sons, Ltd.", "author_names": [ "Andres Rodriguez-Seijo", "Maria C Alfaya", "Maria Luisa Andrade", "Flora A Vega" ], "corpus_id": 130768123, "doc_id": "130768123", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Copper, Chromium, Nickel, Lead and Zinc Levels and Pollution Degree in Firing Range Soils", "venue": "", "year": 2016 }, { "abstract": "Abstract The influence of superficial phosphorus rich layers during the metallization firing treatment on carrier recombination and trapping in copper contaminated multicrystalline silicon was investigated. Copper contaminated wafers experienced firing steps with and without phosphorus rich layers. The samples fired without phosphorus emitters feature higher bulk carrier lifetimes, but also a stronger sensitivity to the copper related light induced degradation (LID) which was activated by the firing treatment. This last behavior could be used to identify the dominant LID mechanism (boron oxygen related or copper related) in multicrystalline wafers. In addition, only the samples fired without the phosphorus emitters are subjected to trapping effects, probably involving copper atoms initially precipitated. Copper precipitates are virulent recombination centers whereas the electrical activity of interstitial copper is benign. Therefore these experimental results suggest that on the one hand the wafers fired with the phosphorus rich layers contain lower interstitial copper concentrations. On the other hand they would feature higher densities of copper precipitates and/or larger copper precipitates.", "author_names": [ "Sebastien Dubois", "Tleuzhan Turmagambetov", "Jean Paul Garandet", "Helene Lignier", "Nicolas Enjalbert" ], "corpus_id": 99975052, "doc_id": "99975052", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Influence of the solar cells metallization firing treatment on carrier recombination and trapping in copper contaminated multicrystalline silicon: new insights into the role of the phosphorus rich layers", "venue": "", "year": 2016 }, { "abstract": "To provide a method for firing a copper paste, which improves sinterability of copper particles for the purpose of forming a copper wiring line that is decreased in the electrical conductivity. A method for firing a copper paste, which comprises: an application step wherein a copper paste is applied over a substrate; a first heating step wherein the substrate is heated in a nitrogen gas atmosphere containing from 500 ppm to 2,000 ppm (inclusive) of an oxidizing gas in terms of volume ratio after the application step, thereby oxidizing and sintering copper particles in the copper paste; and a second heating step wherein the substrate is heated in a nitrogen gas atmosphere containing 1% or more of a reducing gas in terms of volume ratio after the first heating step, thereby reducing the oxidized and sintered copper oxide.", "author_names": [ "" ], "corpus_id": 150270837, "doc_id": "150270837", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for firing copper paste", "venue": "", "year": 2015 } ]

[ { "abstract": "Complementary metal oxide semiconductor (CMOS) image sensors (CIS) are being widely used in digital video cameras, web cameras, digital single lens reflex camera (DSLR) smart phones and so on, owing to their high level of integration, random accessibility, and low power operation. It needs to be installed with the cover glass in practical applications to protect the sensor from damage, mechanical issues, and environmental conditions, which, however, limits the accuracy and usability of the sensor due to the reflection in the optical path from air to cover glass to air. In this work, the flexible 3D nanocone anti reflection (AR) film with controlled aspect ratio was firstly employed to reduce the light reflection at air/cover glass/air interfaces by directly attaching onto the front and rear sides of the CIS cover glass. As both the front and rear sides of cover glass were coated by the AR film, the output image quality was found to be improved with external quantum efficiency increased by 7% compared with that without AR film. The mean digital data value, root mean square contrast, and dynamic range are increased by 45.14% 38.61% and 57, respectively, for the output image with AR films. These results provide a novel and facile pathway to improve the CIS performance and also could be extended to rational design of other image sensors and optoelectronic devices.", "author_names": [ "Li Tian", "Luo Xiaolei", "Min Yin", "Dongdong Li", "Xinzhong Xue", "Hui Wang" ], "corpus_id": 102379683, "doc_id": "102379683", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Enhanced CMOS image sensor by flexible 3D nanocone anti reflection film", "venue": "", "year": 2017 }, { "abstract": "The present invention relates to: an anti reflection film comprising a hard coating layer, and a low refractive index layer including a binder resin, and hollow inorganic nano particles and solid inorganic nano particles dispersed in the binder resin, wherein a particle size ratio of the hollow particles to the solid particles is 0.26 to 0.55; and an anti reflection film comprising a hard coating layer including a binder resin, and fine organic or inorganic particles dispersed in the binder resin, and a low refractive index layer including a binder resin, and hollow inorganic nano particles and solid inorganic nano particles dispersed in the binder resin, wherein an average particle size ratio of the hollow particles to the solid particles is 0.15 to 0.55, and wherein 70 vol% or more of the solid inorganic nano particles are within 50% of the thickness of the low refractive index layer from the interface between the hard coating layer and the low refractive index layer.", "author_names": [ "" ], "corpus_id": 139811779, "doc_id": "139811779", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Anti reflection film", "venue": "", "year": 2017 }, { "abstract": "We report a photosensitive, double layered anti reflection film, which is composed of a UV cured acrylate film containing a photoluminescent europium(III) complex as a high refractive index layer and a film of a colloidal nano silica as a low refractive index layer. The refractive index of the high refractive index layer can be tuned from 1. 53 to 1.69 as the composition of the europium(III) complex increases. The reflectance of the anti reflection film on the glass substrate is as low as 0.48% when the refractive indices and thicknesses of the two layers are controlled. The anti reflection film is applied as the top layer of a liquid crystal display (LCD) Since the absorption and excitation spectra of the europium(III) complex barely overlap with the backlight spectrum of the LCD, the europium(III) complex in the anti reflection film does not disturb the display images. The images are visible even under irradiation using an indoor fluorescent lamp. It is also possible to highlight a specific point on the display screen using laser light. When a 405 nm laser pointer is aimed at a specific area, the area appeared as a bright red spot.", "author_names": [ "Geo San Lim", "Hyungwoo Kim", "Ji Young Chang" ], "corpus_id": 137420996, "doc_id": "137420996", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Laser highlighting on a flat panel display coated with a double layered anti reflection film containing a europium(III) complex", "venue": "", "year": 2014 }, { "abstract": "[Problem] To provide an anti reflection film that suppresses light scattering, exhibits sufficient anti reflection properties, and is highly durable, and to provide an optical member. [Solution] An anti reflection film (3) configured from: a relief structure layer (10) that has a hydrate of alumina as a main constituent and has a relief structure in which the distance between protrusions is shorter than the wavelength of the light for which reflection is to be suppressed; and an intermediate layer (5) that is disposed between the relief structure layer (10) and a substrate (2) The relief structure layer (10) is configured so that the relief structure has a spatial frequency peak value of 6.5 mm 1 or higher and a film thickness of 250 nm or greater. The intermediate layer (5) is configured from a plurality of layers including, in order from the relief structure layer (10) side to the substrate (2) side, at least a first layer (51) a second layer (52) a third layer (53) a fourth layer (54) a fifth layer (55) a sixth layer (56) a seventh layer (57) and an eighth layer (58)", "author_names": [ "Yuan Tian Shen Yi Lang", "Ji Hong Da Shi" ], "corpus_id": 146476785, "doc_id": "146476785", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Anti reflection film and optical member", "venue": "", "year": 2016 }, { "abstract": "A systematic series of silicon (Si) wafer with microstructured anti reflection film is prepared by femtosecond laser pulse. The dependence of the morphology and optical properties of the microstructured Si on the experimental parameters is thoroughly investigated. With the laser pulse duration of 40 fs, central wavelength of 800 nm, repetition rate of 250 kHz, laser pulse power of 300 mW, 250 mm/s scanning speed, and 2 mm of displacement between the parallel scans in the air, the quasiordered arrays of grain microstructures on the Si wafer up to 800 nm tall and 800 nm diameter at the bottom offered near unity transmission in the mid infrared wavelength. An anti reflection film of approximately 3 x 3 (mm) is developed on the (211) Si substrate with the optimized parameters, Moreover, up to 30% improvement of the response performance is demonstrated.", "author_names": [ "" ], "corpus_id": 135558228, "doc_id": "135558228", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "Microstructuring of anti reflection film for HgCdTe/Si IRFPA with femtosecond laser pulse", "venue": "", "year": 2013 }, { "abstract": "The invention discloses a design and preparation method for a multilayer optical anti reflection film with a single lens spherical aberration compensation function. The design and preparation method comprises the following steps: 1) a wavefront aberration a generated by a spherical aberration on an exit pupil surface after linearly polarized light passes a single lens is calculated, a functional relation between the wavefront aberration a and an angle of incidence is established, the wavefront aberration a is negated, a value is divided by 2 pi, and a remainder which is a wavefront aberration b is obtained; 2) values in multiple intervals of the wavefront aberration b are averaged respectively, and a discretely distributed wavefront aberration c is obtained; 3) corresponding film systems are optimally designed aiming at the multiple intervals, the wavefront aberration c at each angle of incidence is taken as the optimization target for the design of the optical anti reflection film at the corresponding interval, and optimal design of the optical anti reflection film is performed; 4) multiple multilayer optical anti reflection films obtained from design are spliced according to the angles of incidence from small to large, and the optical anti reflection film with compressed single lens spherical aberration is obtained.", "author_names": [ "" ], "corpus_id": 125126478, "doc_id": "125126478", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Design and preparation method for multilayer optical anti reflection film with single lens spherical aberration compensation function", "venue": "", "year": 2015 }, { "abstract": "A method for producing an anti reflection film is provided which is capable of achieving an increase in size in comparison to cases when a vacuum container is used for production. This method for producing an anti reflection film includes a first uneven structure formation step, and a second uneven structure formation step. In the first uneven structure formation step, a first uneven structure is formed on the surface of a base material sheet. In the second uneven structure formation step, a second uneven structure is directly formed on the first uneven structure. The second uneven structure formation step involves plating processing using nickel as a main component. As a result of performing this plating processing, the second uneven structure can be formed with an average arrangement period which is shorter than that of the first uneven structure, said arrangement period being equal to or less than a wavelength to be prevented from being reflected.", "author_names": [ "Mei Ze Peng Yi", "Zao Gu Xiong Yi" ], "corpus_id": 139788995, "doc_id": "139788995", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Method for producing anti reflection film", "venue": "", "year": 2015 }, { "abstract": "The recently developed practice of spraying solutions onto a substrate to fabricate thin films via layer by layer (LBL) method has been further investigated and extended. We successfully fabricated double layer anti reflection (AR) thin films with high and low refractive index layers by the spray layer by layer (spray LBL) method. For the deposition of a high refractive index layer, layers of poly(diallyldimethylammonium chloride) (PDDA) and titanium(IV) bis(ammoniumlactato) dihydroxide (TALH) were alternatively assembled. The average thickness of (PDDA/TALH) was determined to be 7 nm and the refractive index was n=1.76 at 550 nm. Poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) layers were assembled on the high refractive index layer for the deposition of the low refractive index layer. The average thickness of (PAH/PAA) was determined to be 14 nm and the refractive index was n=1.48 at 550 nm. This AR thin film showed the maximum transmittance (94.5% and the minimum reflection (0.5% at approximately 550 nm in wavelength.", "author_names": [ "Kyu Hong Kyung", "Kouji Fujimoto", "Seimei Shiratori" ], "corpus_id": 121516436, "doc_id": "121516436", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Control of Structure and Film Thickness Using Spray Layer by Layer Method: Application to Double Layer Anti Reflection Film", "venue": "", "year": 2011 }, { "abstract": "One kind of anti reflection and anti reflection film structure, comprising two layers of upper and lower outer dielectric layer, the conductive metal layer in the middle and are sandwiched between two layers of anti oxidizing metal layer between the conductive metal layer and two dielectric layers, wherein said anti oxidation metal layer is a zinc or titanium. The actual physical thickness of the antireflection structure in the range of several tens of nanometers, by using the anti reflection structure, the flexible substrate selection, volume by volume magnetron sputtering method, and only achieved dozens thickness having excellent optical properties mass production of antireflection film nm, to overcome the shortcomings of conventional anti reflection film is reduced large area industrial production indicate a new way.", "author_names": [ "" ], "corpus_id": 139162504, "doc_id": "139162504", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "It is an anti anti reflection film structure and Save", "venue": "", "year": 2014 }, { "abstract": "This optical member is provided with: a resin substrate; and an anti reflection film which is formed upon the resin substrate, and which includes alternate layers of a high refractive index layer comprising TiO2, and a low refractive index layer comprising SiO2 and Al2O3. The film thickness of the low refractive index layers accounts for at least 60% but not more than 72.5% of the total film thickness of the anti reflection film. The anti reflection film has an average reflectance at an angle of incidence of 5@ for wavelengths in the range of 420 900 nm of not more than 1.5%", "author_names": [ "Neng Shi Zheng Zhang", "Chuan Lu Zong Ju", "Zhong Cun Kong Er" ], "corpus_id": 139937546, "doc_id": "139937546", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Optical member provided with wide band anti reflection film", "venue": "", "year": 2014 } ]

[ { "abstract": "Semiconductor quantum dots (QDs) have become a unique class of materials with great potential for applications in biomedical and optoelectronic devices. However, conventional QDs contains toxic heavy metals such as Pb, Cd and Hg. Hence, it is imperative to find an alternative material with similar optical properties and low cytotoxicity. Among these materials, CuInS2 (CIS) QDs have attracted a lot of interest due to their direct band gap in the infrared region, large optical absorption coefficient and low toxic composition. These factors make them a good material for biomedical application. This review starts with the origin and photophysical characteristics of CIS QDs. This is followed by various synthetic strategies, including synthesis in organic and aqueous solvents, and the tuning of their optical properties. Lastly, their significance in various biological applications is presented with their prospects in clinical applications.", "author_names": [ "Rajendran Jose Varghese", "Oluwatobi Samuel Oluwafemi" ], "corpus_id": 225176622, "doc_id": "225176622", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "The Photoluminescence and Biocompatibility of CuInS2 Based Ternary Quantum Dots and Their Biological Applications", "venue": "", "year": 2020 }, { "abstract": "Abstract Recently, various materials have been explored for their potential applications in homojunction solar cells, which have distinct advantages of good lattice matching at the junction interfaces with minimum recombination losses of carriers. This paper presents an overview of design, technique, and materials in the advanced homojunction solar cells with their latest reported efficiencies. We review the development of homojunction solar cells with two dimensional (or thin film) based materials, one dimensional materials (nanowire/nanorods/nanotube) and zero dimensional (nanodots and quantum dots) based materials. Among the thin film materials explored for homojunction solar cells, we mainly focus this review on CuInS2, InGaN, and InP based homojunction solar cells.", "author_names": [ "Nisar Ali", "Jingting Luo", "Mingkui Wang", "Abul Kalam", "Abdullah G Al-Sehemi", "Yong Qing Fu" ], "corpus_id": 208717907, "doc_id": "208717907", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Advances in nanostructured homojunction solar cells and photovoltaic materials", "venue": "", "year": 2020 }, { "abstract": "Copper doped semiconductors are classic phosphor materials that have been used in a variety of applications for many decades. Colloidal copper doped semiconductor nanocrystals have recently attracted a great deal of interest because they combine the solution processability and spectral tunability of colloidal nanocrystals with the unique photoluminescence properties of copper doped semiconductor phosphors. Although ternary and quaternary semiconductors containing copper, such as CuInS2 and Cu2ZnSnS4, have been studied primarily in the context of their photovoltaic applications, when synthesized as colloidal nanocrystals, these materials have photoluminescence properties that are remarkably similar to those of copper doped semiconductor nanocrystals. This review focuses on the luminescent properties of colloidal copper doped, copper based, and related copper containing semiconductor nanocrystals. Fundamental investigations into the luminescence of copper containing colloidal nanocrystals are reviewed in the context of the well established luminescence mechanisms of bulk copper doped semiconductors and copper(I) molecular coordination complexes. The use of colloidal copper containing nanocrystals in applications that take advantage of their luminescent properties, such as bioimaging, solid state lighting, and luminescent solar concentrators, is also discussed.", "author_names": [ "Kathryn E Knowles", "Kimberly H Hartstein", "Troy B Kilburn", "Arianna Marchioro", "Heidi D Nelson", "Patrick J Whitham", "Daniel R Gamelin" ], "corpus_id": 206536224, "doc_id": "206536224", "n_citations": 178, "n_key_citations": 1, "score": 0, "title": "Luminescent Colloidal Semiconductor Nanocrystals Containing Copper: Synthesis, Photophysics, and Applications.", "venue": "Chemical reviews", "year": 2016 }, { "abstract": "Solution processed organic and inorganic semiconductors offer a promising path towards low cost mass production of solar cells. Among the various material systems, solution processing of multicomponent inorganic semiconductors offers considerable promise due to their excellent electronic properties and superior photo and thermal stability. This review surveys the recent developments of \"all solution processed\" copper indium gallium) chalcogenide (CuInS2, CuInSe2 and Cu(In, Ga)(Se, S)2) chalcopyrites and copper zinc tin chalcogenide (Cu2ZnSnS4 and Cu2ZnSnSe4 (CZTS(e) kesterite solar cells. A brief overview further addresses some of the most critical material aspects and associated loss mechanisms in chalcopyrite and kesterite devices. Today's state of the art performance as well as future challenges to achieve low cost and environmentally friendly production is discussed.", "author_names": [ "Hamed Azimi", "Yi Hou", "Christoph J Brabec" ], "corpus_id": 97142346, "doc_id": "97142346", "n_citations": 152, "n_key_citations": 1, "score": 0, "title": "Towards low cost, environmentally friendly printed chalcopyrite and kesterite solar cells", "venue": "", "year": 2014 }, { "abstract": "Group I III VI2 semiconductor based quantum dots, such as AgInS2, CuInS2 and their solid solution with ZnS, have recently been reported to show intense photoluminescence, the wavelength of which is tunable in a wide range from visible to near infrared (NIR) light regions by controlling their chemical composition and/or size. Due to their low toxicity and tunable optical properties, these multinary semiconductor quantum dots (QDs) have been intensively developed as alternative materials to conventional Cdand Pb based QDs for applications to photoluminescent devices, photocatalysts, quantum dot solar cells, and biological imaging materials. In this review, the recent progress in the photofunctionality of I III VI2 based semiconductor QDs prepared by the colloidal method is outlined with foucus on two advances: (1) extension of the photoluminescence wavelength to NIR light for in vivo biological imaging and (2) improvement of photoenergy conversion properties by nanostructure control of QDs. (c) The Electrochemical Society of Japan, All rights reserved.", "author_names": [ "Tatsuya Kameyama" ], "corpus_id": 106028213, "doc_id": "106028213", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Advances in Colloidal I III VI 2 Based Semiconductor Quantum Dots toward Tailorable Photofunctional Materials", "venue": "", "year": 2018 }, { "abstract": "Introduction: A number of assays have so far been exploited for detection of cancer biomarkers in various malignancies. However, the expression of cancer biomarker(s) appears to be extremely low, therefore accurate detection demands sensitive optical imaging probes. While optical detection using conventional fluorophores often fail due to photobleaching problems, quantum dots (QDs) offer stable optical imaging in vitro and in vivo. Methods: In this review, we briefly overview the impacts of QDs in biology and its applications in bioimaging of malignancies. We will also delineate the existing obstacles for early detection of cancer and the intensifying use of QDs in advancement of diagnostic devices. Results: Of the QDs, unlike the II VI type QDs (e.g. cadmium (Cd) selenium (Se) or tellurium (Te) that possess inherent cytotoxicity, the I III VI 2 type QDs (e.g. AgInS2, CuInS2, ZnS AgInS2) appear to be less toxic bioimaging agents with better control of band gap energies. As highly sensitive bioimaging probes, advanced hybrid QDs (e.g. QD QD, fluorochrome QD conjugates used for sensing through fluorescence resonance energy transfer (FRET) quenching, and barcoding techniques) have also been harnessed for the detection of biomarkers and the monitoring of delivery of drugs/genes to the target sites. Antibody QD (Ab QD) and aptamer QD (Ap QD) bioconjugates, once target the relevant biomarker, can provide highly stable photoluminescence (PL) at the target sites. In addition to their potential as nanobiosensors, the bioconjugates of QDs with homing devices have successfully been used for the development of smart nanosystems (NSs) providing targeted bioimaging and photodynamic therapy (PDT) Conclusion: Having possessed great deal of photonic characteristics, QDs can be used for development of seamless multifunctional nanomedicines, theranostics and nanobiosensors.", "author_names": [ "Omid Mashinchian", "Mohammad Johari-Ahar", "Behnaz Ghaemi", "Mohammad Reza Rashidi", "Jaleh Barar", "Yadollah Omidi" ], "corpus_id": 12194626, "doc_id": "12194626", "n_citations": 60, "n_key_citations": 0, "score": 0, "title": "Impacts of quantum dots in molecular detection and bioimaging of cancer", "venue": "BioImpacts BI", "year": 2014 }, { "abstract": "AbstractSince the last few decades, light absorbing materials based on CuInGaSe2 (CIGS) CuInS2 (CIS) and CdTe have dominated the research in thin film solar cells. To fabricate large scale solar cells from these materials, problems may arise due to limited availability of the constituents, viz. Se, In, Cd, and Te, and the toxicity of some of these elements. Hence, recent research efforts are attentive toward abundantly available non toxic, larger value of absorption coefficient and non conventional elements. The Cu3BiS3 having wittichenite orthorhombic structure is one the most promising absorber layer candidates for low cost thin film solar cells. It has suitable direct band gap (1.10 1.86 eV) large absorption coefficient (105 cm 1) with composition of earth abundant, and relatively non toxic and cost effective constituents. Till now, a majority work was done on the preparation of Cu3BiS3 thin films by various techniques. Therefore, a comprehensive review of recent literature of Cu3BiS3 is urgently required. This paper will review the various techniques that have been used to deposit Cu3BiS3 semiconductor with the hope of new paths for the beginner.", "author_names": [ "S G Deshmukh", "Vipul Kheraj" ], "corpus_id": 136371359, "doc_id": "136371359", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "A comprehensive review on synthesis and characterizations of Cu3BiS3 thin films for solar photovoltaics", "venue": "Nanotechnology for Environmental Engineering", "year": 2017 }, { "abstract": "In the frame of the present doctoral thesis, chalcopyrite based heterojunctions, used in Thin Film Solar Cells (TFSCs) have been further developed and extensively studied. TFSCs grown at the Helmholtz Zentrum Berlin fur Materialien und Energie (HZB) have been exhaustively characterized by Optical Modulation Techniques at the National Technical University of Athens (NTUA) In accordance with the results anticipated, Cd free chalcopyrite solar cells have been developed and have been structurally, optically, and electrically characterized. The respective buffer(ZnSe) and window layers (ZnO) have been grown by low cost chemical (CBD) and electrochemical (ECD) techniques at the NTUA. In the following, a brief review of the thesis main topics is given: Optical Modulation (Photoreflectance) Studies: The structural and optical properties of chalcopyrite single crystals and monocrystalline epitaxial layers have been analyzed by Optical Modulation Techniques. Photoreflectance has been applied at room and low temperatures to quantify elastic strain effects, to determine compositional changes, and to exploit the light interaction probability of ternary (CuGaSe2, CuInSe2, CuGaS2, CuInS2) and quaternary (CuIn1 xGaxSe2) chalcopyrite absorbers with applications in solar cell device technology. With respect to bulk chalcopyrites, epitaxially grown layers exhibit lower crystal quality because of elastic strain effects evolving in semiconductor heterostructures. The mismatch and thermal strain calculated from the energy shift of the PR spectra have been compared to strain values obtained by X ray Diffraction (XRD) analysis. The dependence of electronic transitions on the polarization state of the excitation light beam and the dependence of chalcopyrite transition energies on anion/cation replacement and temperature has been found in both, bulk crystals and epitaxial layers, to be in agreement with theoretical predictions. The band gap of ternary chalcopyrite semiconductors, bulk and epitaxially grown selenides CuInSe2 and CuGaSe2, has been studied over a wide temperature", "author_names": [ "Konstantina Anestou", "Konstantinos Anestou" ], "corpus_id": 136573880, "doc_id": "136573880", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Development and characterization of chalcopyrite based thin film solar cells for photovoltaic technology applications", "venue": "", "year": 2011 }, { "abstract": "Human need for renewable energy resources leads to invention of renewable energy sources such as Solar Cells (SCs) Historically, the first SCs were built from inorganic materials. Although the efficiency of such conventional solar cells is high, very expensive materials and energy intensive processing techniques are required. In comparison with the conventional scheme, the hybrid Si based SC system has advantages such as; (1) Higher charging current and longer timescale, which make the hybrid system have improved performances and be able to full charge a storage battery with larger capacity during a daytime so as to power the load for a longer time; (2) much more cost effective, which makes the cost for the hybrid PV system reduced by at least 15%(Wu et al. 2005) Thus, hybrid SCs can be a cheap alternative for conventional SCs. One type of hybrid SCs is a combination of both organic and inorganic materials which combines the unique properties of inorganic semiconductors with the film forming properties of conjugated polymers. Organic materials are inexpensive, easily processable, enabling lightweight devices and their functionality can be tailored by molecular design and chemical synthesis. On the other hand, inorganic semiconductors can be manufactured as nanoparticles and inorganic semiconductor nanoparticles offer the advantage of having high absorption coefficients, size tenability and stability. By varying the size of nanoparticles the bandgap can be tuned therefore the absorption range can be tailored (Gunes Sariciftci, 2008) These kinds of hybrid SCs based on organic inorganic materials are fabricated by using different concepts such as solid state dye sensitized SCs and hybrid SCs using Bulk Heterojunction (BHJ) concept such as TiOx(Hal et al. 2003) ZnO (Beek et al. 2006) CdSe (Alivisatos, 1996; Huynh et al. 2002) Cds (Greenham et al. 1996) PbS (McDonald et al.,2005) and CuInS2. Another generation of hybrid SCs are silicon based modules due to the direct bandgap and high efficiency of Si. This system includes SC module consisting of crystalline and amorphous silicon based SCs. The methods for enhancing the efficiencies in these types of hybrid SCs such as applying textured structures for front and back contacts as well as implementing an intermediate reflecting layer (IRL) between the individual cells of the tandem will be discussed (Meillaud et al. 2011) This chapter brings out an overview of principle and working of hybrid SCs consisting of HJ SCs which is itself devided into two groups, first organic inorganic", "author_names": [ "Hossein Movla", "Foozieh Sohrabi", "Arash Nikniazi", "Mohammad Reza Soltanpour", "Khadijeh Khalili" ], "corpus_id": 42251855, "doc_id": "42251855", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Hybrid Solar Cells Based on Silicon", "venue": "", "year": 2011 }, { "abstract": "The development of hybrid inorganic/organic thin film solar cells on flexible, lightweight, space qualified, durable substrates provides an attractive solution for fabricating solar arrays with high mass specific power (W/kg) Next generation thin film technologies may well involve a revolutionary change in materials to organic based devices. The high volume, low cost fabrication potential of organic cells will allow for square miles of solar cell production at one tenth the cost of conventional inorganic materials. Plastic solar cells take a minimum of storage space and can be inflated or unrolled for deployment. We will explore a cross section of in house and sponsored research efforts that aim to provide new hybrid technologies that include both inorganic and polymer materials as active and substrate materials. Research at University of Texas at Arlington focuses on the fabrication and use of poly(isothianaphthene 3,6 diyl) in solar cells. We describe efforts at Norfolk State University to design, synthesize and characterize block copolymers. A collaborative team between EIC Laboratories, Inc. and the University of Florida is investigating multijunction polymer solar cells to more effectively utilize solar radiation. The National Aeronautics and Space Administration (NASA)/Ohio Aerospace Institute (OAI) group has undertaken a thermal analysis of potential metallized substrates as well as production of nanoparticles of CuInS2 and CuInSe2 in good yield at moderate temperatures via decomposition of single source precursors. Finally, preliminary work at the Rochester Institute of Technology (R.I.T. to assess the impact on performance of solar cells of temperature and carbon nanotubes is reported. Technologies that must be developed to enable ultra lightweight solar arrays include: monolithic interconnects, lightweight array structures, and new ultra light support and deployment mechanisms. For NASA applications, any solar cell or array technology must not only meet weight and AMO efficiency goals, but also must be durable enough to survive launch conditions and space environments.", "author_names": [ "Aloysius F Hepp", "Jeremiah S Mcnatt", "Sheila G Bailey", "John Ellis Dickman", "Ryne P Raffaelle", "Brian J Landi", "Annick Anctil", "Roberta A DiLeo", "Michael H -C Jin", "Chun-Young Lee", "Theresa J Friske", "Sam S Sun", "Cheng Zhang", "Sung-Dae Choi", "Abram J Ledbetter", "Kang Deuk Seo", "Carl E Bonner", "Kulbinder K Banger", "Stephanie L Castro", "David Rauh" ], "corpus_id": 137256276, "doc_id": "137256276", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Ultra Lightweight Hybrid Thin Film Solar Cells: A Survey of Enabling Technologies for Space Power Applications", "venue": "", "year": 2007 } ]

[ { "abstract": "Single photon detectors (SPDs) are the most sensitive devices for detecting light. The rapid development of quantum communication over the past decades have given rise to the development of a cheap and miniature SPD device. Its core consists of a single photon avalanche photodiode (SPAD) a specially designed semiconductor device that is sensitive to single photon radiation. Both at the dawn of the development of semiconductor SPDs and nowadays, the SPAD control electronics occupies a special place. In this review, we present technological advances in the development of control electronics for semiconductor SPDs, which operate at a telecommunication wavelength and allow achieving various detrctor's operation modes: low frequency and high frequency gating and a freerun mode. The results of the study of various scientific groups in the field of quantum key distribution, which allows tracing the trends of the world technological development of this industry, from ten km on the ground to communication with satellites, are demonstrated.", "author_names": [ "Anton Losev", "Vladimir Zavodilenko", "Andrey Koziy", "Yuriy V Kurochkin", "Alexander A Gorbatsevich" ], "corpus_id": 235590308, "doc_id": "235590308", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Single Photon Detectors Based on SPADs: Circuit Solutions and Operating Modes", "venue": "", "year": 2021 }, { "abstract": "This paper presents the design of a PXF40 an ultrafast single photon counting (SPC) readout front end electronics implemented in a CMOS 40 nm technology dedicated to hybrid pixel detectors. The prototype application specific integrated circuit core is a matrix of 432 pixels <inline formula> <tex math notation=\"LaTeX\"$24\\times 18$ /tex math>/inline formula> with a <inline formula> <tex math notation=\"LaTeX\"$100\\\\mu \\text {m}\\times 100\\\\mu \\text{m} /tex math>/inline formula> size. The single processing channel consists of a charge sensitive amplifier (CSA) a discriminator, and a 24 bit counter with logic circuitry. The input signal is amplified and formed only by the CSA stage. Depending on the CSA input transistor current value, it can operate in two modes: FAST and FAST_HC with higher current. The measured power dissipation per channel <inline formula> <tex math notation=\"LaTeX\"$P 45 \\mu \\text{W} /tex math>/inline formula> and noise <inline formula> <tex math notation=\"LaTeX\"\\text {ENC} 212\\ \\text {e} /tex math>/inline formula> rms for the FAST mode, while <inline formula> <tex math notation=\"LaTeX\"$P=100\\\\mu \\text{W} /tex math>/inline formula> and ENC 185 e<sup> /sup> rms for the FAST_HC mode, respectively. The readout chip can count up to 1.2 Gcps/mm² based on 10% dead time loss input rate parameter, which is currently the fastest SPC based solution.", "author_names": [ "Rafal Kleczek", "Pawel Grybos", "Robert Szczygiel", "Piotr Maj" ], "corpus_id": 52147091, "doc_id": "52147091", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Single Photon Counting Pixel Readout Chip Operating Up to 1.2 Gcps/mm2 for Digital X Ray Imaging Systems", "venue": "IEEE Journal of Solid State Circuits", "year": 2018 }, { "abstract": "We report on progress in improving fundamental properties of InP based single photon avalanche diodes (SPADs) and recent trends for overcoming dominant performance limitations. Through experimental and modeling work focused on the trade off between dark count rate (DCR) and photon detection efficiency (PDE) we identify the key mechanisms responsible for DCR over a range of operating temperatures and excess bias voltages. This work provides a detailed description of temperature and bias dependent DCR thermal activation energy Ea(T,V) including the crossover from low Ea for trap assisted tunneling at temperatures below ~230 K to larger Ea for thermal generation at temperatures approaching room temperature. By applying these findings to new device design and fabrication, the fundamental tradeoff between PDE and DCR for InP/InGaAs SPADs designed for 1.55 mm photon detection has been managed so that for PDE 20% devices routinely exhibit DCR values of a few kHz, while \"hero\" devices demonstrate that it is possible to achieve sub kHz DCR performance at temperatures readily accessible using thermoelectric coolers. However, important limitations remain, particularly with respect to maximum count rates. Strategies adopted recently to circumvent some of these present limitations include new circuit based solutions involving high speed very short duration gating as well as new monolithic chip level concepts for obtaining improved performance through avalanche self quenching. We discuss these two approaches, and we describe recent results from devices with monolithically integrated quench resistors that achieve rapid self quenching, accompanied by evidence for a partial discharge of the detector capacitance leading to charge flows as low as ~3 x105 carriers associated with each avalanche event.", "author_names": [ "Mark A Itzler", "Xudong Jiang", "Mark Entwistle", "Bora M Onat", "Krystyna Slomkowski" ], "corpus_id": 73683536, "doc_id": "73683536", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Single photon detectors based on InP avalanche diodes: status and prospects", "venue": "Defense Commercial Sensing", "year": 2010 }, { "abstract": "We demonstrate a gated reset circuit with integrated pulse width modulation for CMOS single photon avalanche diodes. The simple design extends the dynamic range and achieve a maximum count rate of 153 MHz. Afterpulsing effect and ranging test using gated reset method is performed and exhibit its advantage over conventional active or passive reset scheme. 1. Introduce CMOS single photon avalanche diodes (SPADs) play a key role in various applications, such as light detection and ranging (LiDAR) for autonomous driving [1] fluorescence lifetime imaging microscopy [2] time gated Raman spectroscopy [3] due to its high sensitivity and excellent timing precision. SPAD's Geiger mode operation enables single photon sensitivity but acquires quenching and reset circuit so unwanted detection deadtime is introduced. This becomes a serious issue when strong background light, for example, sunshine in vehicle LiDAR application, makes SAPDs too busy to detect laser photons. 2. Gated Reset Circuit Passive quenching and reset circuit using a single MOS transistor is the simplest way but the deadtime is long >10 20 ns) due to large resistance during recharging SPAD. To make it shorter without going into complex activereset circuit, very recently, Antolovic et. al. [4] demonstrated that a clock driven scheme could largely extend the dynamic range although the maximum count rate for single SPAD is only about 10 MHz. Fig. 1 explains the basic working principle of clock driven reset using the same passive reset circuit. Different from the operation of conventional passive quenching passive reset using constant gate voltage, clock driven or gated reset scheme does quenching at low gate voltages and recharging at high ones, as shown in the simulated timing diagram in Fig. 2. To enhance the stability and to control the period and duration of the clock driven gate voltage, in this work, a pulse width modulation circuit is integrated on the same chip, as shown in Fig. 3, which can be shared with other SPADs in array applications. Fig. 1 Passive rest and gated reset schematic. Fig. 2 Timing waveform using gated reset method. Fig. 3 Gated reset scheme with an integrated pulse width modulation design and layout. 3. SPAD Device Based on the same device reported previously [5] we use a 20 mm diameter SPAD in this work. The device structure is shown in Fig. 4. The P N junction is formed by DPW and NBL layers with HVPW layer as a guard ring. We have designed and fabricated the chips using TSMC high voltage 0.18 mm CMOS technology without any customization. The breakdown voltage of our SPAD is 48.5V. We operate the SPAD at the excess bias is 2.5V. The corresponding dark count rate (DCR) is 276Hz. The measured spectra of photon detection probability (PDP) at various excess bias voltages are shown in Fig. 5. The maximum PDP is 21.4% at 550 nm at the excess bias of 2.5 V. Fig. 4 Schematic device structure of our SPAD Fig. 5 Photon detection probability (PDP) of our SPAD at different excess bias 4. Dynamic Range Fig. 6 exhibits the dynamic range experiment setup. Using integrator sphere with a 625 nm light emitting diodes as light source, a calibrated photodiode (PD) and the SPAD chip were mounted on the two holes on the sphere. The effective input counts, denoted as n, can be calculated by the measured photocurrent of calibrated PD and the photon detection probability (PDP) of SPAD. That is, n photon flux on SPAD sensing area times PDP. The detector count, denoted as m, is the actual output counts from SPAD. Fig. 7 exhibits the measurement results of dynamic range of the SPAD under gated reset and passive reset operations. In passive reset scheme, where the conventional constant gate voltage was used, the highest count rate of 39.8 MHz was obtained at quenching bias of 0.91 V. In contrast, in gated reset operation (350 MHz clock frequency, 0.6 ns pulse width, gate voltages of 0 V and 1.8 V) the linear region is largely extended and the dynamic range has been significantly increased to a maximum count rate of 153 MHz, about 4 fold enhancement. 0% 10% 20% 30% 500 600 700 800 900 PD P Wavelength (nm) 2.5V 1.5V 0.5V Fig. 6 Dynamic ranges experiment setup Fig. 7 Measured dynamic ranges of passive reset and gated reset methods. 5. Afterpulsing Probability For SPADs, afterpulsing probability (APP) increases with shorten deadtime and increased breakdown current. [6] For gated reset scheme, if a breakdown event occurs during reset period, the breakdown current cannot be quenched immediately so the resultant APP gets worse. The measured APP as a function of the pulse width is plotted in Fig. 8. The clock frequency is fixed at 350 MHz. By reducing the pulse width to 0.6 ns, 3 fold reduction of APP is obtained. Fig. 9 exhibits the measured APP as a function of the clock frequency with fixed pulse width of 0.6ns. Clearly, the APP increases with the increasing clock frequency because occurrence probability of the shorter deadtime is higher. Fig. 8 Measured APP as a function of pulse width. Fig. 9 Measured APP as a function of the clock frequency. 6. Ranging Experiment An intriguing feature using gated reset scheme is its varying deadtimes. This is potentially helpful in LiDAR application. We have performed a ranging experiment using active reset [7] and gated reset schemes with the respective APP of 4.8% and 5.0% The laser condition for ranging is, repetition rate of 2.5 MHz, wavelength of 780 1.0E+06 1.0E+07 1.0E+08 1.0E+09 1.0E+06 1.0E+07 1.0E+08 1.0E+09 1.0E+10 m (H z) n (Hz) Passive Reset Gated Reset", "author_names": [ "C W Hsu", "Chia-Ming Tsai" ], "corpus_id": 210115891, "doc_id": "210115891", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "CMOS Single photon Avalanche Diodes using Gated Reset Circuit with On chip Pulse Width Modulation", "venue": "", "year": 2019 }, { "abstract": "Time Correlated Single Photon Counting (TCSPC) is an essential tool in many scientific applications, where the recording of optical pulses with picosecond precision is required. Unfortunately, a key issue has to be faced: distortion phenomena can affect TCSPC experiments at high count rates. In order to avoid this problem, TCSPC experiments have been commonly carried out by limiting the maximum operating frequency of a measurement channel below 5% of the excitation frequency, leading to a long acquisition time. Recently, it has been demonstrated that matching the detector dead time to the excitation period allows to keep distortion around zero regardless of the rate of impinging photons. This solution paves the way to unprecedented measurement speed in TCSPC experiments. In this scenario, the front end circuits that drive the detector play a crucial role in determining the performance of the system, both in terms of measurement speed and timing performance. Here we present two fully integrated front end circuits for Single Photon Avalanche Diodes (SPADs) a fast Active Quenching Circuit (AQC) and a fully differential current pick up circuit. The AQC can apply very fast voltage variations, as short as 1.6ns, to reset external custom technology SPAD detectors. A fast reset, indeed, is a key parameter to maximize the measurement speed. The current pick up circuit is based on a fully differential structure which allows unprecedented rejection of disturbances that typically affect SPAD based systems at the end of the dead time. The circuit permits to sense the current edge resulting from a photon detection with picosecond accuracy and precision even a few picoseconds after the end of the dead time imposed by the AQC. This is a crucial requirement when the system is operated at high rates. Both circuits have been deeply characterized, especially in terms of achievable measurement speed and timing performance.", "author_names": [ "Giulia Acconcia", "A Cominelli", "Massimo Ghioni", "Ivan Rech" ], "corpus_id": 52030682, "doc_id": "52030682", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Fast fully integrated front end circuit to overcome pile up limits in time correlated single photon counting with single photon avalanche diodes.", "venue": "Optics express", "year": 2018 }, { "abstract": "In recent years, lifetime measurements by means of the Time Correlated Single Photon Counting (TCSPC) technique have led to a significant breakthrough in medical and biological fields. Unfortunately, the many advantages of TCSPC based approaches come along with the major drawback of a relatively long acquisition time. The exploitation of multiple channels in parallel could in principle mitigate this issue, and at the same time it opens the way to a multi parameter analysis of the optical signals, e.g. as a function of wavelength or spatial coordinates. The TCSPC multichannel solutions proposed so far, though, suffer from a tradeoff between number of channels and performance, and the overall measurement speed has not been increased according to the number of channels, thus reducing the advantages of having a multichannel system. In this paper, we present a novel readout architecture for bi dimensional, high density Single Photon Avalanche Diode (SPAD) arrays, specifically designed to maximize the throughput of the whole system and able to guarantee an efficient use of resources. The core of the system is a routing logic that can provide a dynamic connection between a large number of SPAD detectors and a much lower number of high performance acquisition channels. A key feature of our smart router is its ability to guarantee high efficiency under any operating condition.", "author_names": [ "Giulia Acconcia", "A Cominelli", "Ivan Rech", "Massimo Ghioni" ], "corpus_id": 23515690, "doc_id": "23515690", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "High efficiency integrated readout circuit for single photon avalanche diode arrays in fluorescence lifetime imaging.", "venue": "The Review of scientific instruments", "year": 2016 }, { "abstract": "An overview of photon counting detection using CMOS compatible Single Photon Avalanche Diodes (SPAD) will be presented. These SPADs have a planar structure, and are processed using CMOS technology. The most promising aspect of this technology is the potential for building large area arrays that can be operated in photon counting mode without the read out noise and bulkiness associated with low noise CCD cameras. Using the iAQC (integrated Active Quenching Circuit) produced by Micro Photonics Devices, a low noise InGaAs/InAlAs APD will be characterized for photon counting. Finally, Characterization data from a photon counting module using Intevac's IPD's (Tube+APD hybrd) will be presented for photon counting at 1064nm.", "author_names": [ "Nick Bertone", "Roberto Biasi", "Bruno Dion" ], "corpus_id": 66060112, "doc_id": "66060112", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Overview of photon counting detectors based on CMOS processed single photon avalanche diodes (SPAD) InGaAs APDs, and novel hybrid (tube APD) detectors", "venue": "SPIE OPTO", "year": 2005 }, { "abstract": "Recently developed InGaAs/InP devices suitable as single photon avalanche diodes (SPADs) in the near infrared range provide good detection efficiency and low time jitter, together with fairly low dark count rate at moderately low temperature. However, the overall performance is still severely limited by the afterpulsing effect (due to carriers trapped in deep levels during the avalanche and later released) Experimental studies and speculations aiming to improve the overall performance are here presented. The photon detection efficiency is characterized and the primary dark count rate is investigated, taking into account thermal generation in the InGaAs layer (absorption layer) and trap assisted tunneling in the InP layer (multiplication layer) Experimental investigations on the afterpulsing are reported. Improvements obtainable with existing devices by selecting proper operating conditions and circuit solutions are presented and discussed. In order to gain a better insight in the design of new devices, the effectiveness of trapping levels as a function of their location and of the electric field distribution is studied by computer simulation. The fundamental role played by the front end circuits is assessed and demonstrated, in particular as concerns picosecond photon timing for a SPAD operating in gated mode with ultrafast gate on and gate off transitions.", "author_names": [ "Alberto Tosi", "Alberto Dalla Mora", "Franco Zappa", "Sergio Cova" ], "corpus_id": 121328023, "doc_id": "121328023", "n_citations": 61, "n_key_citations": 2, "score": 0, "title": "Single photon avalanche diodes for the near infrared range: detector and circuit issues", "venue": "", "year": 2009 }, { "abstract": "Single photon detectors sensitive to near infrared (NIR) wavelength light are used in an increasing number of applications, such as quantum key distribution, laser detection and ranging, and integrated circuit analysis. There are many types of NIR single photon detectors, e.g. photomultiplier tube, superconducting single photon detector and single photon avalanche diode (SPAD) However, the SPAD remains the most practical of them, mainly because of their relatively high operating temperatures 220 K to room temperature) hence requiring only moderate or no cooling. Most NIR SPADs are InGaAs/InP SPADs, which are sensitive to 1550 nm wavelength light. An InGaAs and an InP layer are used as absorption and avalanche materials, respectively. The main performance parameters for SPADs are Single Photon Detection Efficiency (SPDE) Dark Count Rate (DCR) and After pulsing probability. Simulations [1] have shown that, for a given DCR, SPADs using InAlAs instead of InP as avalanche material achieve higher SPDE, because of higher avalanche breakdown probability (proportional to SPDE) in InAlAs than in InP. Thus SPADs based on InAlAs can potentially achieve higher operating temperature, compared to SPADs based on InP, for given SPDE and DCR. Moreover, breakdown voltage of InAlAs is less sensitive to temperature than InP is [2] offering greater flexibility in the SPAD operation temperature. In this work we report a 50 m diameter InGaAs/InAlAs SPAD for detection of 1550 nm photons. The InGaAs/InAlAs SPAD was grown by molecular beam epitaxy (MBE) and fabricated using standard photolithography and wet chemical etching. The SPAD was characterised in gated mode inside a low temperature probe station. Photons were from a heavily attenuated pulsed laser (20 ps FWHM pulse width) DCR data versus overbias, Vob, at different temperatures and SPDE at 210 K are shown in Fig. 1(a) From 293 to 210 K, DCR reduced by 2 orders of magnitude and a maximum SPDE of 41% was achieved. Despite the relatively large device diameter, these results are significantly better than previous reports of InGaAs/InAlAs SPADs [3 5] as shown in Fig. 1(b)", "author_names": [ "X G Meng", "Shiyu Xie", "X Zhou", "C H Tan", "Jo Shien Ng" ], "corpus_id": 46505956, "doc_id": "46505956", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "InGaAs/InAlAs Single Photon Avalanche Diode at 1550 nm", "venue": "", "year": 2015 }, { "abstract": "We present the design and simulations of a single photon sensitive imager based on single photon avalanche diodes (SPADs) with an innovative pixel architecture that includes four separate SPADs with independent active time gating and quenching circuit, a shared time to digital converter (TDC) with 50 ps resolution, four independent photon counters, and multiple operation modes. The TDC is driven by smart arbitration logic, which preserves spatial information among the four detectors; furthermore, an alternative operation mode exploits photon coincidence on multiple detectors to reduce the effect of high background levels, e.g. in light detection and ranging applications with strong ambient light. Key features are the ability to operate in simultaneous photon counting and timing modes for capturing 2 D and 3 D images of the scene in a single shot (frame) the option of a counting only mode, reducing power consumption, and increasing achievable frame rate when timing information is not needed, and the ability to individually shut down noisy detectors or to enable just some regions of interests.", "author_names": [ "Davide Portaluppi", "Enrico Conca", "Federica A Villa" ], "corpus_id": 11778499, "doc_id": "11778499", "n_citations": 30, "n_key_citations": 1, "score": 0, "title": "32 x 32 CMOS SPAD Imager for Gated Imaging, Photon Timing, and Photon Coincidence", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2018 } ]

[ { "abstract": "Abstract The work showed a novel amperometric NH3 sensor based on SrM2O4 (M Sm, La, Gd, Y) with CaFe2O4 type structural sensing electrode. A distinct B site strategy was developed to prepare a series of semiconductor oxides SrM2O4 (M Sm, La, Gd, Y) to establish the relationships between the band structure and sensing properties of the optimized sensing electrode. The structural analyses carried out by X ray diffraction, scanning electron microscopy and Mott Schottky curves confirm that four metal oxides SrM2O4 (M Sm, La, Gd, Y) are all n type semiconductors, and a preferential sensing mechanism of NH3 sensor was proposed by the combination of mass spectrometry track. The electrochemical results indicate that NH3 sensing properties are closely related to the band structure of the metal semiconductor oxides. Compared with the conduction band obtained from Mott Schottky curves, it is the most negative for SrSm2O4 sensing electrode, suggesting that electrons are easier to overcome energy barriers over SrSm2O4. Consequently, the NH3 sensor with SrSm2O4 sensing electrode exhibits high sensitivity, quicker response/recovery speed, excellent selectivity and stability compared to other three sensors, exhibiting a great application prospects for SrSm2O4 sensing electrode used in the automotive equipments.", "author_names": [ "Jing Cong", "Pei Duan", "Fulan Zhong", "Yu Jiao Luo", "Yong-Chao Zheng", "Guo-hui Cai", "Yi-hong Xiao", "Lilong Jiang" ], "corpus_id": 208762349, "doc_id": "208762349", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Gas sensing properties of amperometric NH3 sensors based on Sm2Zr2O7 solid electrolyte and SrM2O4 (M Sm, La, Gd, Y) sensing electrodes", "venue": "", "year": 2020 }, { "abstract": "Abstract The accelerated decomposition of an Sm2Zr2O7+8YSZ system in the form of air plasma spraying (APS) thermal barrier coatings of composites, double ceramic layer (DCL) and functional graded system (FGS) types under hot corrosion conditions were analyzed. Hot corrosion tests were performed using liquid sodium sulfate salt deposits and then X Ray diffraction (XRD) scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) were performed to identify the reaction products. The obtained data indicated that negligible amounts of sulfates or oxysulfates were formed, but significant decomposition of pyrochlore Sm2Zr2O7 to the fluorite phase was detected. These phenomena were also observed in a much higher temperature range during pure oxidation tests, but the lowest decomposition temperature (920 degC) was observed in the sodium sulfate assisted process. The described observations were confirmed during similar tests and realized using model powder mixtures. Microstructural analysis of thermal barrier coatings (TBC) cross sections revealed a complex decomposition process that was localized to areas near the Sm2Zr2O7 splats. The decomposition of the observed pyrochlore phase was mainly related to interactions between Sm2Zr2O7 and 8YSZ in accordance with the fluxing mechanism typical for the hot corrosion process of Ni based superalloys. Additionally, the effect of eutectic Na Sm O was determined.", "author_names": [ "Grzegorz Moskal", "Sebastian Jucha", "Marta Mikuskiewicz", "Damian Migas", "Anna Jasik" ], "corpus_id": 219008157, "doc_id": "219008157", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Atypical decomposition processes of Sm2Zr2O7 8YSZ dual phase TBCs during hot corrosion", "venue": "", "year": 2020 }, { "abstract": "Abstract Rare earth zirconates are considered as one class of the ideal candidate high temperature structural materials. In this paper, a series of Y3Al5O12 doped Sm2Zr2O7 (1 x)Sm2Zr2O7 xY3Al5O12, x 0, 0.05, 0.1, 0.2, 0.3, mol. composite ceramics were prepared at 1600 degC. The influence of Y3Al5O12 doping on microstructure, mechanical properties and thermal conductivity of Y3Al5O12 doped Sm2Zr2O7 were investigated. The results showed that the composite ceramics were mainly composed of Sm2Zr2O7, Y3Al5O12 and a small amount of SmAlO3 phases. The grain size of Sm2Zr2O7 in composite ceramics obviously decreased with the increase of Y3Al5O12 doping concentration. The fracture toughness of 0.8Sm2Zr2O7 0.2Y3Al5O12 composite ceramic was (2.50 0.14) MPa*m1/2, which was the highest among the investigated ceramic materials, and was about twice as high as that of pure Sm2Zr2O7 ceramic. The thermal conductivity of composite ceramics increased with the rise of Y3Al5O12 doping concentration at above 600 degC. 0.8Sm2Zr2O7 0.2Y3Al5O12 composite ceramic had almost no change in grain size and phase composition before and after sintering at 1400 degC for 100 h, suggesting that 0.8Sm2Zr2O7 0.2Y3Al5O12 composite ceramic had good sintering resistance at 1400 degC.", "author_names": [ "Shuqin Wu", "Zhao Xue", "Xiaojuan Ji", "Eung-sun Byon", "Shihong Zhang" ], "corpus_id": 219914417, "doc_id": "219914417", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Influence of Y3Al5O12 doping on mechanical properties and thermal conductivity of Sm2Zr2O7 Y3Al5O12 composite ceramics", "venue": "", "year": 2020 }, { "abstract": "Abstract The determination of thermal resistance related to splat boundaries in composite TBC (thermal barrier coating) systems and expressed as splat to splat heat transfer coefficient was analyzed. Sm2Zr2O7 and conventional 8YSZ powders were used for coatings deposition by atmospheric plasma spraying. Two types of internal morphology were deposited: monolayered type (Sm2Zr2O7, 8YSZ) and composite TBCs (Sm2Zr2O7 8YSZ with weight ratios of 75/25, 50/50 and 25/75) The primary investigation was related to microstructural characterization of ceramic layers (pores and cracks architecture description) thermal diffusivity and conductivity characterization by laser flash analysis and theoretical models. The thermal conductivity was initially calculated on the basis of thermal diffusivity, heat capacity and density measurement as a function of temperature. Those values were corrected due to the presence of pores (microstructural analysis) and effective vales of thermal conductivity were calculated. These values were used as the basis for additional calculations based on the Hasselman Johnson model of thermal conductivity for composite materials. Based on quantitative data from image analysis and porosity corrected thermal conductivity for monolayered and composite TBC systems, the thermal boundary conductivity (splat to splat heat transfer coefficient) was calculated as a function of temperature for Sm2Zr2O7 8YSZ composite systems.", "author_names": [ "Grzegorz Moskal", "Anna Jasik", "Marta Mikuskiewicz", "Sebastian Jucha" ], "corpus_id": 216295956, "doc_id": "216295956", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Thermal resistance determination of Sm2Zr2O7 8YSZ composite type of TBC", "venue": "", "year": 2020 }, { "abstract": "Abstract The present work demonstrated the heterovalent ions incorporated pyrochlore Sm2Zr2O7 ceramic with high NO2 sensitivity through molecular insights into the bond of [BO6] unit and the sensing mechanism. An effective B site strategy was developed to prepare a series of defective Sm2Zr1.95X0.05O7+d (SZX, X= Mn2+ Ga3+ Sn4+ Nb5+ W6+ ceramics to create oxygen vacancies or interstitial oxygen induced which enhances the NO2 sensing performances. The structural analyses carried out by XRD, SEM, XPS, Raman and the NO2 adsorption on a cold surface of the sensor clarified the potential sensing mechanism. The electrochemical results clearly indicate that NO2 sensing properties are closely related to the valence of doped cations. The sensor of Sm2Zr2O7 with Nb5+ arranged at B sites indicates high sensitivity, quick response/recovery speed, excellent selectivity and stability compared with others, exhibiting great application prospects for the automotive equipment.", "author_names": [ "Yong-Chao Zheng", "Pei Duan", "Zhiyu Li", "Guo-hui Cai", "Fulan Zhong", "Yi-hong Xiao" ], "corpus_id": 216461339, "doc_id": "216461339", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Heterovalent ions incorporated pyrochlore Sm2Zr2O7 ceramic for enhanced NO2 sensing", "venue": "", "year": 2020 }, { "abstract": "A series of Sm2Zr2O7 SiC composites doped with different volume fraction and particle size of SiC were prepared by hot pressing at 1300 degC. The phase of the composites prepared is P Sm2Zr2O7 and C SiC, and no other diffraction peaks exist, which indicates that Sm2Zr2O7 has great chemical compatibility with SiC. The thermal conductivity and phonon thermal conductivity of the Sm2Zr2O7 SiC composites are measured by the laser pulse method. The photon thermal conductivity of the composites is obtained by subtracting the phonon thermal conductivity from the total thermal conductivity. The results show that the photon thermal conductivity of Sm2Zr2O7 SiC composites is lower than that of pure Sm2Zr2O7. The photon thermal conductivity of Sm2Zr2O7 SiC composites decreases first and then increases with the increase of SiC particle size. Sm2Zr2O7 (5 vol% 10 um)SiC composite has the lowest photon thermal conductivity.", "author_names": [ "Zhuang Ma", "Qi Zhang", "Ling Liu", "Yanbo Liu" ], "corpus_id": 220291427, "doc_id": "220291427", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Preparation and heat insulating capacity of Sm2Zr2O7 SiC composites based on photon thermal transport", "venue": "Journal of Advanced Ceramics", "year": 2020 }, { "abstract": "Sm2Zr2O7 (SZO) and Y2O3 partially stabilized ZrO2 (YSZ) composite powders were prepared by agglomeration granulation after ball milling. The size, morphology and phase structure of granulated aggregates were characterized. The SZO/YSZ composite coating was prepared by atmospheric plasma. The effects of heat treatment and plasma spraying on the phase structure of composite powders and its phase stability were studied. The microstructures and phase structures of YSZ/SZO composite powders and coatings were studied by scanning electron microscopy (SEM) and X ray diffraction (XRD) The stability of YSZ/SZO composite powders was investigated by differential scanning calorimetry (DSC) The results indicate that spherical agglomerated SZO and YSZ composite powders are relatively smooth and the structure is compact with a mixed phase structure at room temperature. No phase transformation occuring in the range of room temperature to 1200 degC reveals that the YSZ/SZO powders have suitability in the service temperature. The YSZ/SZO coating has a typical layered structure, and the composition and structure distribution of the coating are relatively uniform. Compared with the single SZO coating, the bonding strength of the YSZ/SZO coating is significantly improved. During plasma spraying, the stability of the powder decreases due to ions diffuse. The ordered phase in SZO transformed to disordered phase and the composite coating only presents a single fluorite structure.", "author_names": [ "" ], "corpus_id": 222139342, "doc_id": "222139342", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Preparation and Properties of YSZ/Sm2Zr2O7 Composite Powders", "venue": "", "year": 2020 }, { "abstract": "Cytotoxicity is a crucial problem in biomedical implant applications which could be overcome by enhancing the corrosion resistance through surface coating technique.Studies on biological properties and bio corrosion and a supported study on microstructureof plasma sprayed Gd2Zr2O7 hydroxyapatite and Sm2Zr2O7 hydroxyapatite coatings on type titanium (Ti 6Al 4V) of grade 5 samples are carried out in this research work. The samples are tested for Bio corrosion behaviour in Artificial Blood Plasma (ABP) as medium to study the corrosion behaviour of ceramic coated titanium (Ti 6Al 4V) The results indicated that the thick and non porous oxide passive layers formed over the ceramic coated samples augmented the corrosion resistance than bare titanium (Ti 6Al 4V) substrates. The tribology test was performed for the coated samples.", "author_names": [ "Gobi Saravanan Kaliaraj", "Anderson Arul Gnana Dhas", "Karthik Alagarsamy", "A M Kamalan Kirubaharan", "Shaik Sarwath Hussain", "Kezia Sasitharan" ], "corpus_id": 234552174, "doc_id": "234552174", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Mechanical and corrosion behaviour of Gd2Zr2O7 HAp and Sm2Zr2O7 HAp composite coated Ti 6Al 4V alloy for biomedical applications", "venue": "", "year": 2020 }, { "abstract": "Abstract It is shown that Sm2Zr2O7 possessing significant coexistence of covalent and ionic features demonstrates very promising stiffness features. The corresponding analysis has been performed using density functional theory (DFT) From the chemical bonding nature, it is observed that the crystal shows significant coexistence of covalent, ionic and semiconducting features in UV VIS spectral range. This crystal is brittle, exhibits higher stiffness. The elastic anisotropy of the crystal is discussed and visualized. It is shown a possibility to use them as highly optical anisotropic materials which are promising for different optoelectronic and photoelastic devices. The origin of the anisotropy and possible changes of the content to improve the optoelectronics and mechanical features are discussed. The performed studies have been based on the full potential linearized augmented plane wave (FP LAPW) method with generalized gradient plus Hubbard parameter (GGA U) method. It was discovered a direct type of band energy gap situated at G point of Brillouin zone of Sm2Zr2O7 for spin up and down polarizations. The detailed analysis of the origin of optical functions like absorption coefficient, dielectric constant, energy loss function; refractive index, reflectivity, extinction coefficient and optical conductivity are explored. The possible ways of change of optical functions are in desirable directions.", "author_names": [ "Muhammad Irfan", "Sikander Azam", "Madiha Makhdoom", "Banat Gul", "Iwan V Kityk", "Shabbir Muhammad", "Saifeldin M Siddeeg" ], "corpus_id": 197615254, "doc_id": "197615254", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "DFT simulations of optoelectronic and elastic features of cubic samarium zirconate (Sm2Zr2O7)", "venue": "", "year": 2019 }, { "abstract": "Abstract Fluorite and pyrochlore type compounds (Pr2Zr2O7, Sm2Zr2O7 and PrSmZr2O7) powders were prepared by glycine nitrate process (GNP) starting from metal (Sm, Pr) nitrate, zirconium chloride and glycine as a fuel. The GNP process at room temperature initially yielded amorphous powders, which crystallized after subsequent calcination to form crystalline ceramics. The formation of well crystalline compounds took place at temperature as low as 950degC. The phase evolution with thermal treatment as well as powder properties such as crystallite size, lattice strain and lattice parameter were studied by X ray powder diffraction (XRPD) at room temperature. High density ceramic pellets free of any additives were obtained after compaction of the obtained powders and subsequent sintering at 1600degC for 4 h in air. Sintering behaviour of the synthesized pyrochlore phases was followed with a scanning electron microscope. Hardness of the sintered samples was found to be in range of 8.9 to 9.9 GPa depending of chemical composition.", "author_names": [ "Branko Matovic", "Jelena Maletaskic", "Katsumi Yoshida", "Toyohiko Yano" ], "corpus_id": 202214199, "doc_id": "202214199", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Synthesis, characterization and sintering of fluorite and pyrochlore type compounds: Pr2Zr2O7, Sm2Zr2O7 and PrSmZr2O7", "venue": "", "year": 2019 } ]

[ { "abstract": "There is an increasing need for highly accurate 3D inspection and measurement capabilities for applications in SMT, semiconductor and metrology markets. 3D Multiple Reflection Suppression (MRS) sensor technology has been effectively combined with Automated Optical Inspection for several years and is now being utilized for many SPI applications such as microelectronics and sub 100 micron solder paste deposits and other challenging applications, like packaging, automotive, medical and other applications with stringent quality requirements. In addition to inspection, there is an increasing need to capture coordinate measurements inline. Phase shift profilometry (PSP) is widely used for 3D automated optical inspection (AOI) by electronics manufacturers assembling printed circuit boards (PCB) using automated surface mount technologies (SMT) Conventional PSP measurements are significantly challenged by inaccuracies caused by multiple reflections between surfaces on the inspected object. Multiple Reflection Suppression (MRS) sensor technology addresses this challenge. The sensor's unique optical architecture and the system's proprietary image fusing and processing algorithms provide fast, accurate 3D characterization capabilities that are well suited to other important applications, including solder paste inspection (SPI) and measurements typically performed by coordinate measurement machines (CMM) Coordinate measurements can now be attained in seconds, rather than the hours or days it would take a traditional coordinate measurement machine. MRS sensor technology provides significant advantages in speed, accuracy and resolution over the alternate technologies. This technology is a key building block for achieving high accuracy at production speed for Automated Optical Inspection (AOI) Solder Paste Inspection (SPI) and Coordinate Measurement (CMM) applications.", "author_names": [ "Dick Johnson", "John Hoffman" ], "corpus_id": 145042032, "doc_id": "145042032", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Fast Accurate 3 D Sensor Technology for Automated Optical Inspection Solder Paste Inspection and Coordinate Measurements", "venue": "", "year": 2018 }, { "abstract": "The process of printing and inspecting solder paste deposits in Printed Circuit Boards (PCB) involves a very large number of variables (more than 30000 can be found in 3D inspection of high density PCBs) State of the art Surface Mount Technology (SMT) production lines rely on 100% inspection of all paste deposits for each PCB produced. Specification limits for Area, Height, Volume, Offset X and Offset Y have been defined based on detailed and consolidated studies. PCBs with paste deposits failing the defined criteria, are proposed to be rejected.", "author_names": [ "Pedro Delgado", "Cristina Martins", "Ana Cristina Braga", "Claudia Barros", "Isabel Delgado", "Carlos Marques", "Paulo Sampaio" ], "corpus_id": 49695510, "doc_id": "49695510", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Benefits of Multivariate Statistical Process Control Based on Principal Component Analysis in Solder Paste Printing Process Where 100% Automatic Inspection Is Already Installed", "venue": "ICCSA", "year": 2018 }, { "abstract": "The growth of the electronics industry led to a need for efficient methods of testing and validation of printed circuit boards (PCB) It is necessary to identify defects that might appear in a component in early production stages. This task may be performed by automatic inspection systems, showing advantages in speed, accuracy and repeatability, over human inspection. This paper describes a visual inspection system that is able to detect solder paste deposition defects on a PCB. The PCB image is analysed to segment the areas with solder paste and then, by comparing with reference data from the PCB design files, defects are identified, either because of missing or excess solder. The system is based on low cost components, namely a Raspberry Pi Compute Module and two Raspberry Pi v2 cameras. Experimental tests performed with the prototype, regarding the PCB defect detection and execution time, allowed to conclude the system can aid human visual inspection in a production line.", "author_names": [ "Guilherme B F Paulo", "Luis Perdigoto", "Sergio M M Faria" ], "corpus_id": 235207668, "doc_id": "235207668", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Automatic visual inspection system for solder paste deposition in PCBs", "venue": "2021 Telecoms Conference (ConfTELE)", "year": 2021 }, { "abstract": "With the explosion in the electronics market, PCB manufacturing has taken a very important place. The manufacturers use Gerber file as the only reference for PCB drawing since it gives the most accurate details of the solder pads to be etched on the PCB. Due to this feature of the Gerber file, we are using it in our proposal of PCB inspection mechanism. Gerber is a text file specifying the shape, dimensions and coordinates of the solder pads. Firstly, it is parsed so that these details could be extracted. From this information, the locations are tracked on the PCB image captured and the corresponding solder pad is cropped. The amount of solder paste applied is calculated by computing the area covered by the solder pad. Correspondingly, the ideal area, as given by the Gerber file is found out. Upon comparison of these two areas, the various PCB defects like deficient, excessive can be found out. Displacement faults are found out by calculating the centroid of the different solder pads on the PCB and comparing with the locations given by Gerber.", "author_names": [ "Vediya Sitaram Raghuvanshi", "A Burman", "Prashant P Bartakke", "Satish Deshpande" ], "corpus_id": 14819827, "doc_id": "14819827", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "PCB solder pad inspection mechanism using gerber file", "venue": "2016 International Conference on Communication and Signal Processing (ICCSP)", "year": 2016 }, { "abstract": "A solder printing inspection device (10) measures the volume of solder paste on a land on a PCB and sends inspection result information, including the measured volume, to an inspection data management device (102) From an image of the PCB after reflow, a solder attachment inspection device (30) extracts data on characteristics of the solder site being inspected, and said solder attachment inspection device communicates with the inspection data management device (102) to acquire the volume of solder paste at the point corresponding to the solder site being inspected, as measured by the solder printing inspection device (10) Said volume is then used to infer characteristics of nearby areas for which it is difficult to measure characteristics; the results of said inference are used together with the data on the abovementioned characteristics to compute the wetting height of the solder after reflow; and said height is classified as passing or failing.", "author_names": [ "Teng Jing Xin Ping", "Hong Zhi Sen", "Ke Qi Zhong Dao", "Gu Shang Chang Shen" ], "corpus_id": 140967052, "doc_id": "140967052", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solder attachment inspection method, solder attachment inspection device, and pcb inspection system", "venue": "", "year": 2011 }, { "abstract": "A solder printing inspection device (10) measures the volume of solder paste on a land on a PCB, and a solder attachment inspection device (30) measures the wetting height of the solder after reflow. Said solder attachment inspection device (30) contains: an inspection program which contains a plurality of evaluation criteria for evaluating the measured wetting height; and a selection rule for selecting from said evaluation criteria. Said selection rule defines which evaluation criterion to select depending on the volume of solder paste on the solder site being inspected, as measured by the solder printing inspection device (10) The solder printing inspection device (10) reads, from an inspection data management device (102) the solder paste volume corresponding to the solder site being inspected and determines the aforementioned evaluation criterion on the basis thereof.", "author_names": [ "Teng Jing Xin Ping", "Hong Zhi Sen", "Ke Qi Zhong Dao", "Gu Shang Chang Shen" ], "corpus_id": 146305578, "doc_id": "146305578", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solder attachment inspection method, pcb inspection system, and solder attachment inspection device", "venue": "", "year": 2011 }, { "abstract": "Quality inspection of PCB is a crucial stage in the assembly line as it provides an insight on whether the board works correctly or not. When the inspection is done manually, it is susceptible to human errors and is time consuming. The boards should thus be inspected at every stage of the assembly line and the process should be dynamic. This is achieved in this work through three crucial stages in the assembly line and by replacing the conventional manual inspection by using image processing to obtain a faster and more precise quality inspection. The solder paste inspection consists of preprocessing using blue plane conversion, comparing with the unsoldered board in blue color plane and post processing using overlay. The X ray inspection basically consists of preprocessing the captured image by RGB to gray conversion with thresholding, comparing with the expected image and post processing using overlay to show the shorts that has occurred along the assembly. The conformal coating inspection uses conversion of the blue intensity emitted off the board under UV light to RGB scale. Each of the algorithms were tested using 48 actual in production boards from Vinyas IT Pvt Ltd, a PCB assembly company based in Mysore. The processing time of the algorithms were found to be less than 2 seconds with an accuracy of 85.7% The system was also found to be cost eff ective over existing systems available in the market.", "author_names": [ "Dr P Madhan Kumar" ], "corpus_id": 221662068, "doc_id": "221662068", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Automated Quality Inspection of PCB Assembly Using Image Processing", "venue": "", "year": 2020 }, { "abstract": "In this paper, we introduce an automated Bayesian visual inspection framework for printed circuit board (PCB) assemblies, which is able to simultaneously deal with various shaped circuit elements (CEs) on multiple scales. We propose a novel hierarchical multi marked point process model for this purpose and demonstrate its efficiency on the task of solder paste scooping detection and scoop area estimation, which are important factors regarding the strength of the joints. A global optimization process attempts to find the optimal configuration of circuit entities, considering the observed image data, prior knowledge, and interactions between the neighboring CEs. The computational requirements are kept tractable by a data driven stochastic entity generation scheme. The proposed method is evaluated on real PCB data sets containing 125 images with more than 10 000 splice entities.", "author_names": [ "Csaba Benedek", "Oliver Krammer", "Mihaly Janoczki", "Laszlo Jakab" ], "corpus_id": 13194395, "doc_id": "13194395", "n_citations": 46, "n_key_citations": 4, "score": 0, "title": "Solder Paste Scooping Detection by Multilevel Visual Inspection of Printed Circuit Boards", "venue": "IEEE Transactions on Industrial Electronics", "year": 2013 }, { "abstract": "Detection of solder paste by image processing is a new approach in the solder paste inspection.image quality is one of the keys to ensure the accuracy of image detection.The image acquisition is a vital role for the protection of image quality.It's also a critical step in a series of processing steps to eventually obtain images useful information.This paper focuses on three main parameters of focal length,exposure and gain affecting the quality of solder paste image acquisition.The experimental demonstration of the reasonable range of the three main parameters of the focus,exposure and gain.As well as the functional relationship between shutter speed and gain.Providing a basis for the adjustment of solder paste image acquisition paramenters,but also laid the foundation for the follow up study for parameters adjustment automatically of the paste image acquisition.", "author_names": [ "Ye Hai" ], "corpus_id": 63839947, "doc_id": "63839947", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solder Paste Image Acquisition Parameters of the PCB", "venue": "", "year": 2012 }, { "abstract": "Increased functional density and reduced input/output (I/O) spacing are the market trends in the electronics manufacturing industry. Industry reports indicate that approximately 50% 70% of soldering defects are attributed to the solder paste printing process for printed circuit board (PCB) assembly. Hence, after the printing process, a solder paste inspection (SPI) system is generally used to examine the amount of solder paste deposition. Effective selection of components and bonding pads during solder inspection is extremely important in achieving desired process cycle times and ensuring assembly yield. This paper uses the Mahalanobis Taguchi system to establish a systematic approach to determining guidelines for solder paste inspection. Among a total of 203 bonding pads on the board for a GPS product, the optimal model suggests that the solder deposition of 121 bonding pads be inspected. The reduction ratio is 40.4% and the feasibility of the proposed model is verified. Also, for those bonding pads to be inspected for their solder paste deposition, this study uses empirical data to define the specifications to effectively distinguish acceptable PCB samples from defective. The threshold is within the 100% capability for judgment of solder paste printing quality in the surface mount assembly process.", "author_names": [ "J C Huang" ], "corpus_id": 34747350, "doc_id": "34747350", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Reducing Solder Paste Inspection in Surface Mount Assembly Through Mahalanobis Taguchi Analysis", "venue": "IEEE Transactions on Electronics Packaging Manufacturing", "year": 2010 } ]

[ { "abstract": "Reconfigurability of photonic integrated circuits (PICs) has become increasingly important due to the growing demands for electronic photonic systems on a chip driven by emerging applications, including neuromorphic computing, quantum information, and microwave photonics. Success in these fields usually requires highly scalable photonic switching units as essential building blocks. Current photonic switches, however, mainly rely on materials with weak, volatile thermo optic or electro optic modulation effects, resulting in large footprints and high energy consumption. As a promising alternative, chalcogenide phase change materials (PCMs) exhibit strong optical modulation in a static, self holding fashion, but the scalability of present PCM integrated photonic applications is still limited by the poor optical or electrical actuation approaches. Here, with phase transitions actuated by in situ silicon PIN diode heaters, scalable nonvolatile electrically reconfigurable photonic switches using PCM clad silicon waveguides and microring resonators are demonstrated. As a result, intrinsically compact and energy efficient switching units operated with low driving voltages, near zero additional loss, and reversible switching with high endurance are obtained in a complementary metal oxide semiconductor (CMOS) compatible process. This work can potentially enable very large scale CMOS integrated programmable electronic photonic systems such as optical neural networks and general purpose integrated photonic processors.", "author_names": [ "Jiajiu Zheng", "Zhuoran Fang", "Changming Wu", "Shifeng Zhu", "Peipeng Xu", "Jonathan K Doylend", "Sanchit Deshmukh", "Eric Pop", "Scott T Dunham", "Mo Li", "Arka Majumdar" ], "corpus_id": 220072986, "doc_id": "220072986", "n_citations": 37, "n_key_citations": 1, "score": 0, "title": "Nonvolatile Electrically Reconfigurable Integrated Photonic Switch Enabled by a Silicon PIN Diode Heater.", "venue": "Advanced materials", "year": 2020 }, { "abstract": "We demonstrate the first multi stage 8 x 8 silicon photonic switch with switching elements based on dual add drop microrings with a compact footprint of 4 mm2. This device leverages co design of the switch architecture and the switching elements with a well balanced set of performance metrics. The switching elements are designed to have a 3 dB optical passband of 165 GHz, exhibiting off and on resonance losses of 0.67 dB and 2 dB, respectively. Full characterization of all switch paths shows an end to end on chip loss between 4.4 and 9.6 dB, with worst case crosstalk leakage averaged at 16 dB. Owing to the efficient doped waveguide thermo optic phase shifters, the device features a tuning efficiency of 48.85 GHz/mW. The reconfiguration time of the switch fabric is measured to be 1.2 ms and 0.5 ms at the rise and fall edge, respectively. The dual microring switching element together with the multi stage architecture preserves an end to end passband over 55 GHz. We validate the switch performance with optical paths of varying numbers of on and off resonance switching elements less than 2 dB power penalties are obtained for all data routings at 32 Gbps.", "author_names": [ "Yishen Huang", "Qixiang Cheng", "Yu-Han Hung", "Hang Guan", "Xiang Meng", "Ari Novack", "Matthew Streshinsky", "Michael Hochberg", "Keren Bergman" ], "corpus_id": 208542588, "doc_id": "208542588", "n_citations": 11, "n_key_citations": 1, "score": 1, "title": "Multi Stage 8 x 8 Silicon Photonic Switch Based on Dual Microring Switching Elements", "venue": "Journal of Lightwave Technology", "year": 2020 }, { "abstract": "Disaggregation enabled by silicon photonic switch fabrics is a path to low cost and energy efficient data centers. The routing strategy, which can be seamlessly incorporated into the switch control plane, potentially provides an additional dimension for the physical layer performance optimization, at no extra cost. In this paper, we analyze the role of optical routing strategies for silicon photonic switch fabrics. We define and quantify the number of global switching states in various switching topologies and discuss their relationship to the number of switch permutations. We propose a topology agnostic approach that is shown to optimize fabric wide switch path power penalties and consequently reduce the dynamic range requirement on receivers. Additionally, it potentially compensates for device fabrication variations by taking advantage of the redundancy in switching states over switch permutations; thus, increasing fabrication tolerance. Significant power penalty improvements are demonstrated via both our simulation and test platforms, even for moderate scale silicon switches.", "author_names": [ "Qixiang Cheng", "Yishen Huang", "Hao Yang", "Meisam Bahadori", "Nathan C Abrams", "Xiang-gao Meng", "Madeleine Strom Glick", "Yang Liu", "Michael Hochberg", "Keren Bergman" ], "corpus_id": 211481012, "doc_id": "211481012", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Silicon Photonic Switch Topologies and Routing Strategies for Disaggregated Data Centers", "venue": "IEEE Journal of Selected Topics in Quantum Electronics", "year": 2020 }, { "abstract": "We present a strictly nonblocking $4$ x $4$ electrooptic silicon photonic switch fabric with on chip gain. The switch integrates 12 Mach Zehnder cells in a 3 stage topology equipped with fast electrooptic phase shifters, and thermooptic phase trimmers. To compensate for the losses of the fabric, a 4 channel GaInAsP/InP semiconductor optical amplifier array is flip chip attached into an etched cavity in the silicon photonic chip with butt coupled waveguide interfaces. The chip is wirebonded to a CMOS driver that provides push pull drive to each elementary Mach Zehnder cell. We demonstrate an optical switch assembly with net neutral insertion loss in the C band together with nanosecond scale reconfiguration time.", "author_names": [ "Nicolas Dupuis", "Fuad E Doany", "Russell A Budd", "Laurent Schares", "Christian W Baks", "Daniel M Kuchta", "Takako Hirokawa", "Benjamin G Lee" ], "corpus_id": 210005137, "doc_id": "210005137", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "A $4$ x $4$ Electrooptic Silicon Photonic Switch Fabric With Net Neutral Insertion Loss", "venue": "", "year": 2020 }, { "abstract": "We demonstrate a fully packaged digitally programmable 8x8 strictly nonblocking electrooptic silicon photonics switch module. We measured fiber to fiber loss between 7.5 and 10.5 dB, crosstalk 30 dB, and reconfiguration time 10 ns.", "author_names": [ "Nicolas Dupuis", "Jonathan E Proesel", "Nicolas Boyer", "Herschel A Ainspan", "Christian W Baks", "Fuad E Doany", "Elaine Cyr", "Benjamin G Lee" ], "corpus_id": 216241251, "doc_id": "216241251", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "An 8x8 Silicon Photonic Switch Module with Nanosecond Scale Reconfigurability", "venue": "2020 Optical Fiber Communications Conference and Exhibition (OFC)", "year": 2020 }, { "abstract": "Photonic switching technologies show potential for transforming communication networks across diverse markets from long haul to short reach distance scales due to their large bandwidth density, high energy efficiency, and potential for low cost. In recent years, numerous outstanding advancements have been made in scaled silicon photonic switching fabrics: spanning a variety of manufacturing platforms and packaging methods, relying on different switching mechanisms, and assembled on chip in a diverse mixture of loosely related architectures. This paper reviews the current approaches employed by leading researchers in this area, and surveys the state of the art in achieved performance at both the technological and the architectural level. Specifically, we consider thermo optic, electro optic, and MEMS based switch actuation embedded in Mach Zehnder interferometer, ring resonator, and directional coupler based silicon photonic switches. We define common metrics and compare performances. We outline critical requirements for constructing scaled switch fabrics from elementary cells. We investigate similarities and differences between a number of commonly utilized topologies. And, we survey recent accomplishments in scaled switch fabrics at the chip and package level. Moving these demonstrations from research to product will require many further advancements, and we highlight areas that we believe will be critical for market adoption.", "author_names": [ "Benjamin G Lee", "Nicolas Dupuis" ], "corpus_id": 59600304, "doc_id": "59600304", "n_citations": 41, "n_key_citations": 3, "score": 0, "title": "Silicon Photonic Switch Fabrics: Technology and Architecture", "venue": "Journal of Lightwave Technology", "year": 2019 }, { "abstract": "Efficient integrated photonic switches play a critical role in both interchip optical interconnects and data center networks that need to be dynamically reconfigured. Here, we demonstrate a 1 x 2 switch using phase change material Ge Sb Te (GST) combined with a silicon nitride microring resonator. The switch operates by utilizing the dramatic difference in the optical refractive index and extinction coefficient between the crystalline and amorphous phases of GST. By patterning and encapsulating the GST into subwavelength structures, the device achieves a low insertion loss of less than 1 dB in both output ports and can be switched reliably both photothermally and electrothermally.", "author_names": [ "Changming Wu", "Heshan Yu", "Huan Li", "Xiaohang Zhang", "Ichiro Takeuchi", "Mo Li" ], "corpus_id": 125376560, "doc_id": "125376560", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Low Loss Integrated Photonic Switch Using Subwavelength Patterned Phase Change Material", "venue": "", "year": 2019 }, { "abstract": "First demonstration of a dual microring 8x8 silicon photonic switch in a compact 4 mm2 footprint shows 4.4 8.4 dB end to end on chip loss, 16.75 dB first order switching crosstalk, and 40 GHz switching bandwidth capable of high data rate datacenter transmissions.", "author_names": [ "Yishen Huang", "Qixiang Cheng", "Yu-Han Hung", "Hang Guan", "Ari Novack", "Matthew Streshinsky", "Michael Hochberg", "Keren Bergman" ], "corpus_id": 116428323, "doc_id": "116428323", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Dual Microring Resonator Based 8x8 Silicon Photonic Switch", "venue": "2019 Optical Fiber Communications Conference and Exhibition (OFC)", "year": 2019 }, { "abstract": "We present an all digital, fully programmable, nanosecond scale photonic switch platform, monolithically integrating electronics for actuation, tuning, and power monitoring alongside switching elements, resulting in a scalable, packageable solution for high radix photonic switch fabrics. In this platform, we achieve record loss and extinction performances utilizing a 2x2 Mach Zehnder switch (MZS) with 0.8 dB of loss and 28 dB extinction and a 2x2 nested MZS with 1.3 dB of loss and 38 dB extinction.", "author_names": [ "Nicolas Dupuis", "Jonathan E Proesel", "Herschel A Ainspan", "Christian W Baks", "Mounir Meghelli", "Benjamin G Lee" ], "corpus_id": 199054854, "doc_id": "199054854", "n_citations": 5, "n_key_citations": 2, "score": 0, "title": "Nanosecond photonic switch architectures demonstrated in an all digital monolithic platform.", "venue": "Optics letters", "year": 2019 }, { "abstract": "The mechanism of Cooper pair formation and its underlying physics has long occupied the investigation into high temperature (high Tc cuprate superconductors. One of the ways to unravel this is to observe the ultrafast response present in the charge carrier dynamics of a photoexcited specimen. This results in an interesting approach to exploit the dissipation less dynamic features of superconductors to be utilized for designing high performance active subwavelength photonic devices with extremely low loss operation. Here, dual channel, ultrafast, all optical switching and modulation between the resistive and the superconducting quantum mechanical phase is experimentally demonstrated. The ultrafast phase switching is demonstrated via modulation of sharp Fano resonance of a high Tc yttrium barium copper oxide (YBCO) superconducting metamaterial device. Upon photoexcitation by femtosecond light pulses, the ultrasensitive cuprate superconductor undergoes dual dissociation relaxation dynamics, with restoration of superconductivity within a cycle, and thereby establishes the existence of dual switching windows within a timescale of 80 ps. Pathways are explored to engineer the secondary dissociation channel which provides unprecedented control over the switching speed. Most importantly, the results envision new ways to accomplish low loss, ultrafast, and ultrasensitive dual channel switching applications that are inaccessible through conventional metallic and dielectric based metamaterials.", "author_names": [ "Yogesh Kumar Srivastava", "Manukumara Manjappa", "Longqing Cong", "Harish N S Krishnamoorthy", "Vassili Savinov", "Prakash Pitchappa", "Ranjan Singh" ], "corpus_id": 46946129, "doc_id": "46946129", "n_citations": 47, "n_key_citations": 1, "score": 0, "title": "A Superconducting Dual Channel Photonic Switch.", "venue": "Advanced materials", "year": 2018 } ]

[ { "abstract": "Abstract Advanced oxidation processes (AOPs) introduce a hopeful technology for the removal of water polluted with hard degradable organic compounds. Today, one of the main effective AOP technologies to degrade these hazardous organics is via the photocatalytic process. The present review focuses on the recent progress in the fixed bed and immobilized nanophotocatalysts and also their applications for resolving the environmental concerns. Various organics elimination using a variety of photocatalysts and innovative reactors are discussed. This critical review summarizes the recent progress in the synthesis and modification (physical and chemical) of semiconductors. Furthermore, different ways of photocatalysts immobilization are explained in details. By considering different dangerous chemicals present in wastewater and different industries, catalytic methods used by researchers to degrade these organic compounds are reviewed. In addition, the degradation pathway of some organics through the catalytic operation is described.", "author_names": [ "Abdollah Gholami Akerdi", "Seyed Hajir Bahrami" ], "corpus_id": 199181210, "doc_id": "199181210", "n_citations": 41, "n_key_citations": 0, "score": 1, "title": "Application of heterogeneous nano semiconductors for photocatalytic advanced oxidation of organic compounds: A review", "venue": "Journal of Environmental Chemical Engineering", "year": 2019 }, { "abstract": "Peroxymonosulfate (HSO5 and PMS) is an optional bulk oxidant in advanced oxidation processes (AOPs) for treating wastewaters. Normally, PMS is activated by the input of energy or reducing agent to generate sulfate or hydroxyl radicals or both. This study shows that PMS without explicit activation undergoes direct reaction with a variety of compounds, including antibiotics, pharmaceuticals, phenolics, and commonly used singlet oxygen (1O2) traps and quenchers, specifically furfuryl alcohol (FFA) azide, and histidine. Reaction time frames varied from minutes to a few hours at pH 9. With the use of a test compound with intermediate reactivity (FFA) electron paramagnetic resonance (EPR) and scavenging experiments ruled out sulfate and hydroxyl radicals. Although 1O2 was detected by EPR and is produced stoichiometrically through PMS self decomposition, 1O2 plays only a minor role due to its efficient quenching by water, as confirmed by experiments manipulating the 1O2 formation rate (addition of H2O2) or lifetime (deuterium solvent isotope effect) Direct reactions with PMS are highly pH and ionic strength sensitive and can be accelerated by (bi)carbonate, borate, and pyrophosphate (although not phosphate) via non radical pathways. The findings indicate that direct reaction with PMS may steer degradation pathways and must be considered in AOPs and other applications. They also signal caution to researchers when choosing buffers as well as 1O2 traps and quenchers.", "author_names": [ "Yi Yang", "Gourab Banerjee", "Gary W Brudvig", "Jae-Hong Kim", "Joseph J Pignatello" ], "corpus_id": 206579261, "doc_id": "206579261", "n_citations": 194, "n_key_citations": 1, "score": 0, "title": "Oxidation of Organic Compounds in Water by Unactivated Peroxymonosulfate.", "venue": "Environmental science technology", "year": 2018 }, { "abstract": "Schiff bases and their complexes are good candidates as versatile compounds which are synthesized by the condensation of a primary amino compound with either aldehydes or ketones for a variety of industrial applications. They can act as catalysts in the catalytic oxidation of organic compounds. Recent researches in oxidation catalysis have focused on how to employ the metal catalyzed oxidation of organic substrates. This review summarizes the current developments of the last few decades for the oxidations of organic compounds that proceed through Schiff base complexes. The chemical syntheses of Schiff bases and their complexes are outlined.", "author_names": [ "Wail Al Zoubi", "Young Gun Ko" ], "corpus_id": 99010370, "doc_id": "99010370", "n_citations": 50, "n_key_citations": 0, "score": 0, "title": "Schiff base complexes and their versatile applications as catalysts in oxidation of organic compounds: part I", "venue": "", "year": 2017 }, { "abstract": "Abstract Carbon nanotubes (CNTs) have been found to activate persulfates (i.e. peroxymonosulfate and peroxydisulfate) into reactive species that are capable of oxidizing organic compounds in water. In the presence of single or multi walled CNTs, persulfates effectively degraded phenolic compounds and certain pharmaceuticals. Phenyl derivatives substituted with electron withdrawing groups, such as benzoic acid and nitrobenzene, were resistant to degradation by the CNT/persulfate system. Based on observations regarding persulfate decomposition and linear sweep voltammetry using a CNT electrode, it has been suggested that persulfates bind onto the surface of CNTs, forming reactive complexes that are immediately decomposed upon reaction with organic compounds. Electron paramagnetic resonance spectroscopy with spin trapping indicates that these reactive species are distinct from sulfate radical anions or hydroxyl radicals. The CNT activated persulfate system shows promise as a novel treatment technology for the selective oxidation of organic contaminants in water.", "author_names": [ "Hongshin Lee", "Hye Jin Lee", "Joonseon Jeong", "Jaesang Lee", "Noh-Back Park", "Changha Lee" ], "corpus_id": 97260307, "doc_id": "97260307", "n_citations": 332, "n_key_citations": 7, "score": 0, "title": "Activation of persulfates by carbon nanotubes: Oxidation of organic compounds by nonradical mechanism", "venue": "", "year": 2015 }, { "abstract": "Abstract This review presents a critical assessment of the kinetics and mechanisms of the oxidation of organic compounds, X (organosulfur compounds, amines, phenols, alcohols, hydrocarbons, ascorbate, and pharmaceuticals) by ferrate(VI) (Fe VI O 4 2 and ferrate(V) (Fe V O 4 3 The rate constants k app M 1 s 1 of reactions of these compounds with ferrate(VI) and ferrate(V) usually decrease with increase in pH in alkaline media and the species specific rate constants were evaluated from pH dependent kinetics. The rate constants for the reactions of HFe VI O 4 and HFe V O 4 2 with X were correlated with 1 e and 2 e reduction potentials in order to understand the mechanisms of the reactions. Ferrate(V) generally oxidizes compounds by a 2 e transfer step. The reactions of ferrate(VI) with compounds may be characterized most commonly by (i) a 1 e transfer step from Fe(VI) to Fe(V) followed by a 2 e transfer to Fe(III) as the reduced product (Fe VI Fe V Fe III and (ii) 2 e transfer steps (Fe VI Fe IV Fe II Oxygen atom transfer to the compounds may occur through involvement of either ferrate(VI) or ferrate(V) in the oxidations carried out by ferrate(VI) Hammett type relationships of reactions provided additional information on intermediates involved in oxidation processes and proposed mechanisms are consistent with the oxidized products of the reactions. Oxidation of biological species by ferrate(VI) is also briefly presented.", "author_names": [ "Virender Kumar Sharma" ], "corpus_id": 94488147, "doc_id": "94488147", "n_citations": 197, "n_key_citations": 8, "score": 0, "title": "Ferrate(VI) and ferrate(V) oxidation of organic compounds: Kinetics and mechanism", "venue": "", "year": 2013 }, { "abstract": "Significance Highly oxygenated molecules are involved in autooxidation reactions leading to the formation of secondary organic aerosols (SOAs) they are also critical intermediates in autooxidation processes for liquid hydrogen degradation and the ignition of fuels in advanced combustion systems. However, these reactions are still poorly understood. In this study, we unveil a generalized reaction mechanism involving the autooxidation of peroxy radicals with at least three stages of sequential O2 addition. We elucidate important underlying kinetics and structural characteristics of autooxidation processes used for developing new technologies including those aimed at reducing climatically active SOAs and pollutants from fuel combustion. We show that advances can be made by bridging experimental and theoretical methods used by atmospheric and combustion scientists. Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g. alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g. normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500 600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H atom migration reactions are presented to rationalize the relationship between the organic compound's molecular structure (n alkane, branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. Finally, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.", "author_names": [ "Zhandong Wang", "Denisia M Popolan-Vaida", "Bingjie Chen", "Kai Moshammer", "Samah Y Mohamed", "Heng Wang", "Salim Sioud", "Misjudeen A Raji", "Katharina Kohse-Hoinghaus", "Nils Hansen", "Philippe Dagaut", "Stephen R Leone", "S Mani Sarathy" ], "corpus_id": 21393432, "doc_id": "21393432", "n_citations": 52, "n_key_citations": 2, "score": 0, "title": "Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds", "venue": "Proceedings of the National Academy of Sciences", "year": 2017 }, { "abstract": "Abstract The development of new metal complex catalysts and efficient protocols for the mild and selective oxidation of alkanes, arenes, olefins, alcohols, and other organic substrates is a challenging topic in areas of homogeneous catalysis, coordination, and organic chemistry. In these oxidation reactions, the activity of many metal complex catalysts is dramatically improved upon addition of certain co catalysts or promoters, which can also act as ligands in simple catalytic systems generated in situ. Given the fact that 2 pyrazinecarboxylic acid (Hpca) and analogous heteroaromatic acids such as 2,3 pyrazinedicarboxylic (H 2 pdca) picolinic (Hpic) and dipicolinic (H 2 dipic) acids are remarkably efficient and versatile co catalysts in a high diversity of oxidation systems, the present review summarizes the state of the art knowledge in this field. In particular, this contribution focuses on the use of Hpca as the most active co catalyst and describes its coordination chemistry with regard to the oxidative transformations of various organic substrates, providing an overview of isolated vanadium, iron, and some other transition metal complexes derived from Hpca. The review also summarizes the applications of Hpca assisted and related systems in the oxidation of various organic substrates by different oxidants, and highlights the main selectivity, kinetic, and mechanistic features of these oxidative transformations. The paper covers the application of catalytic systems wherein Hpca, H 2 pdca, Hpic, and H 2 dipic are used either as co catalysts (additives) or as ligands within a metal complex catalyst. A special emphasis has been made on the oxidation of alkanes as very inert substrates, and the use of simple and highly efficient [VO 3 /Hpca/H 2 O 2 system. The multifaceted roles of Hpca and analogous co catalysts have been identified and the analysis of main mechanistic pathways and possible intermediates has been performed.", "author_names": [ "Alexander M Kirillov", "Georgiy B Shul'pin" ], "corpus_id": 64759826, "doc_id": "64759826", "n_citations": 114, "n_key_citations": 2, "score": 0, "title": "Pyrazinecarboxylic acid and analogs: Highly efficient co catalysts in the metal complex catalyzed oxidation of organic compounds", "venue": "", "year": 2013 }, { "abstract": "The gram negative metal reducing microorganism, previously known as strain GS 15, was further characterized. This strict anaerobe oxidizes several short chain fatty acids, alcohols, and monoaromatic compounds with Fe(III) as the sole electron acceptor. Furthermore, acetate is also oxidized with the reduction of Mn (IV) U (VI) and nitrate. In whole cell suspensions, the c type cytochrome(s) of this organism was oxidized by physiological electron acceptors and also by gold, silver, mercury, and chromate. Menaquinone was recovered in concentrations comparable to those previously found in gram negative sulfate reducers. Profiles of the phospholipid ester linked fatty acids indicated that both the anaerobic desaturase and the branched pathways for fatty acid biosynthesis were operative. The organism contained three lipopolysaccharide hydroxy fatty acids which have not been previously reported in microorganisms, but have been observed in anaerobic freshwater sediments. The 16S rRNA sequence indicated that this organism belongs in the delta proteobacteria. Its closest known relative is Desulfuromonas acetoxidans. The name Geobacter metallireducens is proposed.", "author_names": [ "Derek R Lovley", "Stephen J Giovannoni", "David C White", "James E Champine", "Elizabeth J P Phillips", "Yuri A Gorby", "Steve Goodwin" ], "corpus_id": 21365293, "doc_id": "21365293", "n_citations": 712, "n_key_citations": 52, "score": 0, "title": "Geobacter metallireducens gen. nov. sp. nov. a microorganism capable of coupling the complete oxidation of organic compounds to the reduction of iron and other metals", "venue": "Archives of Microbiology", "year": 2004 }, { "abstract": "It is well known that urbanization and industrialization have resulted in the rapidly increasing emissions of volatile organic compounds (VOCs) which are a major contributor to the formation of secondary pollutants (e.g. tropospheric ozone, PAN (peroxyacetyl nitrate) and secondary organic aerosols) and photochemical smog. The emission of these pollutants has led to a large decline in air quality in numerous regions around the world, which has ultimately led to concerns regarding their impact on human health and general well being. Catalytic oxidation is regarded as one of the most promising strategies for VOC removal from industrial waste streams. This Review systematically documents the progresses and developments made in the understanding and design of heterogeneous catalysts for VOC oxidation over the past two decades. It addresses in detail how catalytic performance is often drastically affected by the pollutant sources and reaction conditions. It also highlights the primary routes for catalyst deactivation and discusses protocols for their subsequent reactivation. Kinetic models and proposed oxidation mechanisms for representative VOCs are also provided. Typical catalytic reactors and oxidizers for industrial VOC destruction are further discussed. We believe that this Review will provide a great foundation and reference point for future design and development in this field.", "author_names": [ "Chi He", "Jie Cheng", "Xin Zhang", "Mark Douthwaite", "Samuel Pattisson", "Zhengping Hao" ], "corpus_id": 73471972, "doc_id": "73471972", "n_citations": 362, "n_key_citations": 0, "score": 1, "title": "Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources.", "venue": "Chemical reviews", "year": 2019 }, { "abstract": "Summary The oxidation of a range of organic compounds at a nickel anode in aqueous alkaline solution has been studied and the conversion of primary alcohols, secondary alcohols and primary amines to carboxylic acids, ketones and nitriles respectively have been shown to be efficient processes. most of these organic compounds oxidise at the same potential, the potential at which the surface of the nickel anode itself becomes oxidised. The kinetics for these anodic oxidations have been studied and a mechanism has been proposed to explain the behaviour observed.", "author_names": [ "Martin L Fleischmann", "Karl A Korinek", "Derek Pletcher" ], "corpus_id": 98429892, "doc_id": "98429892", "n_citations": 607, "n_key_citations": 1, "score": 0, "title": "The oxidation of organic compounds at a nickel anode in alkaline solution", "venue": "", "year": 1971 } ]

[ { "abstract": "Whereas size effects have been investigated extensively and are largely understood, it is significantly more challenging to elucidate how functional properties of semiconductors can be altered and ultimately be improved by a hierarchical nanoarchitecture. For semiconductor applications, such as in photovoltaics or photocatalysis, it is of great importance to learn how to avoid the recombination of photogenerated charge carriers and how to enhance their lifetime. A gas phase synthesis method is explored, which enables the generation of spherical zinc oxide nanostructures with compact, mesoporous, a special type of core shell, so called yolk shell, or hollow character. The particles with hollow character exhibit an extraordinarily long persistence of photogenerated charge carriers. It is demonstrated that the presence of the ZnO shell and its special orientation with respect to the polar character of the wurtzite lattice represent deciding factors. After photoexcitation, electrons and holes migrate to oppos.", "author_names": [ "Stefan Dilger", "Martin Wessig", "M R Wagner", "Juan Sebastian Reparaz", "Clivia M Sotomayor Torres", "Liang Qijun", "Thomas Dekorsy", "Sebastian Polarz" ], "corpus_id": 18454025, "doc_id": "18454025", "n_citations": 19, "n_key_citations": 0, "score": 0, "title": "Nanoarchitecture Effects on Persistent Room Temperature Photoconductivity and Thermal Conductivity in Ceramic Semiconductors: Mesoporous, Yolk Shell, and Hollow ZnO Spheres", "venue": "", "year": 2014 }, { "abstract": "In this work, we investigate the optoelectronic properties of zinc oxide (ZnO) nanowires, which are good candidates for applications based on integrated optics. Single ZnO nanowire photodetectors were fabricated with ohmic contacts. By taking current transient measurements in different atmospheres (oxygen, air, vacuum and argon) and at various temperatures, we point out the importance of surface effects on the electrical behaviour. Results confirm that oxygen chemisorption is responsible for the existence of a high photoconductive gain in these devices, and for the first time a two step process in the photocurrent rise transient is reported. A maximum gain of G 7.8 x 107 is achieved. However, under certain conditions, the persistence of the photocurrent can last up to several hours and as such may prevent the device from operating at useful rates. From a knowledge of the photocurrent response mechanisms, we establish a method to restore the photodetector to its initial state, with very low dark current, by applying an appropriate gate voltage sequence. This advances the state of the art for these detectors towards commercial applications.", "author_names": [ "J Ph Girard", "Louis Giraudet", "Sergei Kostcheev", "Bogdan Bercu", "Tim J Puchtler", "R A Taylor", "Christophe Couteau" ], "corpus_id": 52812429, "doc_id": "52812429", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "Mitigating the photocurrent persistence of single ZnO nanowires for low noise photodetection applications.", "venue": "Nanotechnology", "year": 2018 }, { "abstract": "Persistent organic pollutants (POPs) are carbon based chemical substances that are resistant to environmental degradation and may not be completely removed through treatment processes. Their persistence can contribute to adverse health impacts on wild life and human beings. Thus, the solar photocatalysis process has received increasing attention due to its great potential as a green and eco friendly process for the elimination of POPs to increase the security of clean water. In this context, ZnO nanostructures have been shown to be prominent photocatalyst candidates to be used in photodegradation owing to the facts that they are low cost, non toxic and more efficient in the absorption across a large fraction of the solar spectrum compared to TiO2. There are several aspects, however, need to be taken into consideration for further development. The purpose of this paper is to review the photo degradation mechanisms of POPs and the recent progress in ZnO nanostructured fabrication methods including doping, heterojunction and modification techniques as well as improvements of ZnO as a photocatalyst. The second objective of this review is to evaluate the immobilization of photocatalyst and suspension systems while looking into their future challenges and prospects.", "author_names": [ "Chin Boon Ong", "Law Yong Ng", "Abdul Wahab Mohammad" ], "corpus_id": 116389546, "doc_id": "116389546", "n_citations": 862, "n_key_citations": 5, "score": 0, "title": "A review of ZnO nanoparticles as solar photocatalysts: Synthesis, mechanisms and applications", "venue": "", "year": 2018 }, { "abstract": "Polymer composites have established an excellent position among the technologically essential materials because of their wide range of applications. An enormous research interest has been devoted to zinc oxide (ZnO) based polymer nanocomposites, due to their exceptional electrical, optical, thermal, mechanical, catalytic, and biomedical properties. This article provides a review of various polymer composites consisting of ZnO nanoparticles (NPs) as reinforcements, exhibiting excellent properties for applications such as the dielectric, sensing, piezoelectric, electromagnetic shielding, thermal conductivity and energy storage. The preparation methods of such composites including solution blending, in situ polymerization, and melt intercalation are also explained. The current challenges and potential applications of these composites are provided in order to guide future progress on the development of more promising materials. Finally, a detailed summary of the current trends in the field is presented to progressively show the future prospects for the development of ZnO containing polymer nanocomposite materials.", "author_names": [ "Deepalekshmi Ponnamma", "John-John Cabibihan", "Mariappan Rajan", "Sethu Sundar Pethaiah", "Kalim Deshmukh", "Jyoti Prasad Gogoi", "S K Khadheer Pasha", "M Basheer Ahamed", "Jagadish Krishnegowda", "Bananakere Nanjegowda Chandrashekar", "Anji Reddy Polu", "Chun Cheng" ], "corpus_id": 73462894, "doc_id": "73462894", "n_citations": 92, "n_key_citations": 0, "score": 0, "title": "Synthesis, optimization and applications of ZnO/polymer nanocomposites.", "venue": "Materials science engineering. C, Materials for biological applications", "year": 2019 }, { "abstract": "We studied experimentally the granular structures prepared on the base of ZnO thin films. The influence of acceptor or donor complex, caused by oxygen vacancy and interstitial zinc atom, and impurities (Li or Ga) on the crystallite structure conductivity has been investigated. The effect of granule size and crystallite structure on conductivity and photoconductivity was studied. The new method for determination of electric current dependence on spatial coordinates in thin conducting film was developed, which allowed to diagnose a one dimensional conductivity in ZnO:Ga films. The experimental results are interpreted on the basis of the scaling hypothesis and the percolation theory.", "author_names": [ "Armen Poghosyan", "N R Aghamalyan", "E Y Elbakyan", "Ruyan Guo", "Ruben K Hovsepyan", "S I Petrosyan" ], "corpus_id": 122517633, "doc_id": "122517633", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Photoconductivity of ZnO based granular structures", "venue": "Optics Photonics Optical Engineering Applications", "year": 2014 }, { "abstract": "The advance of reliable and eco friendly strategies for the development of nanoparticles is a fundamental key to the discipline of nanotechnology. Nanoparticles have been continuously evaluated and have been used in many industrial applications for a decade. In particular, the role of zinc oxide nanoparticles (ZnO NPs) has received a great interest because of various properties such as UV filter properties and photochemical, antifungal, high catalyst, and antimicrobial activities. Because of the high rate of poisonous chemicals and the extreme surroundings used within the chemical and physical methods, the green techniques have been adopted using plants, fungi, bacteria, and algae for the synthesis of nanoparticles. Therefore, this paper considers various green synthesis methods to provide the evidence of ZnO NP role to several applications, and in addition, biomedical applications and toxic effect were reviewed. Therefore, the paper used various secondary sources to collect the relevant review articles. From the findings, the green route of synthesis is rather safe and eco friendly when compared to physical and chemical means of synthesis. On the other hand, its biomedical applications in this sector are increased day by day in various processes including bioimaging, drug delivery, biosensors, and gene delivery. With respect to its toxicity properties, ZnO NPs can act as smart weapons against multiple drug resistant microorganisms and as a talented substitute for antibiotics.", "author_names": [ "V N Kalpana", "V Devi Rajeswari" ], "corpus_id": 52100600, "doc_id": "52100600", "n_citations": 96, "n_key_citations": 2, "score": 0, "title": "A Review on Green Synthesis, Biomedical Applications, and Toxicity Studies of ZnO NPs", "venue": "Bioinorganic chemistry and applications", "year": 2018 }, { "abstract": "Herein, we synthesized ZnO nanorods using a solvothermal reaction technique at 200 degC for 24 h, and the prepared ZnO nanorods were decorated with silver (Ag) nanoparticles to enhance their photocatalytic activity. The Ag nanoparticles were photochemically deposited on the ZnO rods with varying molar concentrations (from 0.5 to 10 mol% and their various physicochemical properties were studied. The prepared material was characterised using different spectroscopic techniques. XRD revealed the formation of a highly crystalline hexagonal phase of ZnO. For a higher silver loading >5 mol% separate peaks corresponding to cubic silver were observed in the XRD pattern. The photoluminescence spectra of the Ag/ZnO nanostructures show two distinct peaks at 390 and 500 nm; interestingly, the PL intensity of the ZnO emission peak at 500 nm decreases with an increase in the silver concentration. The diffuse reflectance spectra of Ag/ZnO indicate absorbance at 380 nm due to ZnO and a slight hump at 440 nm that corresponds to silver nanoparticles. The FE SEM and TEM analysis indicates the formation of a hexagonal rod like morphology, with the lengths of the rods ranging from around 50 to 200 nm and a diameter of around 30 nm. TEM also confirms the presence of Ag nanoparticles with sizes in the range of 20 to 30 nm on the surface of the ZnO nanorods. The photocatalytic activity of the Ag/ZnO nanostructures was evaluated by following the degradation of methylene blue (MB) dye under a 400 W mercury vapour lamp. ZnO with 10 mol% Ag loading shows the highest photocatalytic activity as compared to the 0.5, 1 5 mol% Ag ZnO catalysts. The observed apparent rate constant for the photocatalytic MB degradation using 10 mol% Ag ZnO (Kapp 6.01 x 10 2 min 1) was six times that of pure ZnO (Kapp 1.09 x 10 2 min 1) A gradual increase in the photocatalytic activity of Ag/ZnO was observed with an increase in the silver concentration. The photocurrent response of the prepared Ag ZnO nanostructures was examined by a photoconductivity study. Moreover, the photocatalytic performance of the sample was correlated with the photoconductivity of the samples. The photoconductivity of the samples was stable, and the photoconductivity of 10 mol% Ag ZnO was almost 20 times that of pure ZnO, resulting in a higher photocatalytic activity.", "author_names": [ "Prashant Pimpliskar", "S C Motekar", "G G Umarji", "Wonyoung Lee", "Sudhir S Arbuj" ], "corpus_id": 108294860, "doc_id": "108294860", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "Synthesis of silver loaded ZnO nanorods and their enhanced photocatalytic activity and photoconductivity study.", "venue": "Photochemical photobiological sciences Official journal of the European Photochemistry Association and the European Society for Photobiology", "year": 2019 }, { "abstract": "The deposition of oxygen defective ZnO films exhibiting varied nanostructures via Solution Precursor Plasma Spray (SPPS) route, a one step, minute scaled duration and large scale method, is reported. The in situ formation of oxygen vacancies in ZnO films was confirmed by UV Visible, Raman and photoluminescence (PL) spectroscopy and the as prepared samples exhibit a bandgap as low as 3.02 eV. Density functional theory (DFT) simulation demonstrates that the polarization of ZnO is enhanced by the created oxygen vacancies, leading to substantially improved photocatalytic activity. The comparative experiments also revealed that forming and preserving appropriate ZnO precursor clusters inside the plasma plume is requisite for obtaining propitious ZnO nanostructures, which was followed by the in situ transfer and growth of the clusters on the preheated substrate. The ZnO NRs films fully degrade the aqueous Orange II dye solutions within 120 min and maintain a quasi intact activity (95.8% retention) after five test runs, which highlight their good stability. The oxygen vacancies and the narrowing of the bandgap also enable a visible light driven photodegradation activity with conversions as high as 54.1% In summary, this work not only reveals that the photocatalytic activity of SPPS deposited ZnO films benefit from oxygen vacancies and well nanostructures, but also suggests that the SPPS route is of high potential for preparing metal oxides films destined to functional applications.", "author_names": [ "Zexin Yu", "Hatem Moussa", "Yangzhou Ma", "Meimei Liu", "Bilel Chouchene", "Raphael Schneider", "Michel Moliere", "Hanlin Liao" ], "corpus_id": 52895261, "doc_id": "52895261", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Oxygen defective ZnO films with various nanostructures prepared via a rapid one step process and corresponding photocatalytic degradation applications.", "venue": "Journal of colloid and interface science", "year": 2019 }, { "abstract": "We successfully synthesized of ZnO/Mn TiO2 (Mn Ti) nano composite for different ZnO:Mn (Zn M) concentrations. These composites with high photo catalytic activity derived from TiO2 and Zn M nanoparticles elaborated by the sol gel method. The SEM and TEM images indicated that samples reveals well ordered and good size distribution of particles. In addition, the composite sample showed no aggregation in similitude with the anatase TiO2 sample. The study of optical properties of nano composites shows that Zn M nanoparticles caused to increase the optical activity of Mn Ti composites samples and it established by UV Vis, photo luminescence, and photo catalytic tests. The XRD study exhibited that in ours composites samples with increasing the Zn M concentration, the particle size increased from 10 to 27 nm. PL measurements suggest that co emission of a strong luminescence, high yellow emission at 563 nm, at 640 nm and at 774 nm is observed from the Mn Ti composites samples. The photo catalytic activity of the prepared nano composite was examined for the degradation of methyl orange (MO) by the irradiation of UV light.", "author_names": [ "K Omri", "Norah Alonizan" ], "corpus_id": 106109270, "doc_id": "106109270", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Effects of ZnO/Mn Concentration on the Micro structure and Optical Properties of ZnO/Mn TiO2 Nano composite for Applications in Photo Catalysis", "venue": "Journal of Inorganic and Organometallic Polymers and Materials", "year": 2018 }, { "abstract": "Zinc oxide films are typically found to be n type, and conductive under most growth conditions and growth methods. Co doping with multiple elements is one strategy for improving the electrical and optical properties of zinc oxide materials for optoelectronic device applications. Using pulsed laser deposition, thin ZnO films were grown on c axis oriented sapphire. The films were co doped with nitrogen and tellurium. Depending on the relative concentrations of the dopants, the resistivity of the films was observed to increase by several orders of magnitude, significantly improving the photoconductive response. The enhancement of the photosensitivity reached a maximum at a tellurium concentration of around 1020cm 3.", "author_names": [ "H L Porter", "A L Cai", "John F Muth", "Jagdish Narayan" ], "corpus_id": 121757161, "doc_id": "121757161", "n_citations": 68, "n_key_citations": 0, "score": 0, "title": "Enhanced photoconductivity of ZnO films Co doped with nitrogen and tellurium", "venue": "", "year": 2005 } ]

[ { "abstract": "Preface. 1 Introduction. 1.1 Historical Perspective. 1.2 Basic Concepts. 1.3 Optical Communication Systems. 1.4 Lightwave System Components. Problems. References. 2 Optical Fibers. 2.1 Geometrical Optics Description. 2.2 Wave Propagation. 2.3 Dispersion in Single Mode Fibers. 2.4 Dispersion Induced Limitations. 2.5 Fiber Losses. 2.6 Nonlinear Optical Effects. 2.7 Fiber Design and Fabrication. Problems. References. 3 Optical Transmitters. 3.1 Semiconductor Laser Physics. 3.2 Single Mode Semiconductor Lasers. 3.3 Laser Characteristics. 3.4 Optical Signal Generation. 3.5 Light Emitting Diodes. 3.6 Transmitter Design. Problems. References. 4 Optical Receivers. 4.1 Basic Concepts. 4.2 Common Photodetectors. 4.3 Receiver Design. 4.4 Receiver Noise. 4.5 Coherent Detection. 4.6 Receiver Sensitivity. 4.7 Sensitivity Degradation. 4.8 Receiver Performance. Problems. References. 5 Lightwave Systems. 5.1 System Architectures. 5.2 Design Guidelines. 5.3 Long Haul Systems. 5.4 Sources of Power Penalty. 5.5 Forward Error Correction. 5.6 Computer Aided Design. Problems. References. 6 Multichannel Systems. 6.1 WDM Lightwave Systems. 6.2 WDM Components. 6.3 System Performance Issues. 6.4 Time Division Multiplexing. 6.5 Subcarrier Multiplexing. 6.6 Code Division Multiplexing. Problems. References. 7 Loss Management. 7.1 Compensation of Fiber Losses. 7.2 Erbium Doped Fiber Amplifiers. 7.3 Raman Amplifiers. 7.4 Optical Signal To Noise Ratio. 7.5 Electrical Signal To Noise Ratio. 7.6 Receiver Sensitivity and Q Factor. 7.7 Role of Dispersive and Nonlinear Effects. 7.8 Periodically Amplified Lightwave Systems. Problems. References. 8 Dispersion Management. 8.1 Dispersion Problem and Its Solution. 8.2 Dispersion Compensating Fibers. 8.3 Fiber Bragg Gratings. 8.4 Dispersion Equalizing Filters. 8.5 Optical Phase Conjugation. 8.6 Channels at High Bit Rates. 8.7 Electronic Dispersion Compensation. Problems. References. 9 Control of Nonlinear Effects. 9.1 Impact of Fiber Nonlinearity. 9.2 Solitons in Optical Fibers. 9.3 Dispersion Managed Solitons. 9.4 Pseudo linear Lightwave Systems. 9.5 Control of Intrachannel Nonlinear Effects. Problems. References. 10 Advanced Lightwave Systems. 10.1 Advanced Modulation Formats. 10.2 Demodulation Schemes. 10.3 Shot Noise and Bit Error Rate. 10.4 Sensitivity Degradation Mechanisms. 10.5 Impact of Nonlinear Effects. 10.6 Recent Progress. 10.7 Ultimate Channel Capacity. Problems. References. 11 Optical Signal Processing. 11.1 Nonlinear Techniques and Devices. 11.2 All Optical Flip Flops. 11.3 Wavelength Converters. 11.4 Ultrafast Optical Switching. 11.5 Optical Regenerators. Problems. References. A System of Units. B Acronyms. C General Formula for Pulse Broadening. D Software Package.", "author_names": [ "Govind P Agrawal" ], "corpus_id": 108425658, "doc_id": "108425658", "n_citations": 3531, "n_key_citations": 391, "score": 1, "title": "Fiber optic communication systems", "venue": "", "year": 1992 }, { "abstract": "Celebrating the 20th anniversary of Optics Express, this paper reviews the evolution of optical fiber communication systems, and through a look at the previous 20 years attempts to extrapolate fiber optic technology needs and potential solution paths over the coming 20 years. Well aware that 20 year extrapolations are inherently associated with great uncertainties, we still hope that taking a significantly longer term view than most texts in this field will provide the reader with a broader perspective and will encourage the much needed out of the box thinking to solve the very significant technology scaling problems ahead of us. Focusing on the optical transport and switching layer, we cover aspects of large scale spatial multiplexing, massive opto electronic arrays and holistic optics electronics DSP integration, as well as optical node architectures for switching and multiplexing of spatial and spectral superchannels.", "author_names": [ "Peter J Winzer", "D Neilson", "Andrew R Chraplyvy" ], "corpus_id": 52168806, "doc_id": "52168806", "n_citations": 232, "n_key_citations": 2, "score": 0, "title": "Fiber optic transmission and networking: the previous 20 and the next 20 years [Invited]", "venue": "Optics express", "year": 2018 }, { "abstract": "Abstract Surface plasmon resonance has established itself as an immensely acclaimed and influential optical sensing tool with quintessential applications in life sciences, environmental monitoring, clinical diagnostics, pharmaceutical developments and ensuring food safety. The implementation of sensing principle of surface plasmon resonance employing an optical fiber as a substrate has concomitantly resulted in the evolution of fiber optic surface plasmon resonance as an exceptionally lucrative scaffold for chemical and biosensing applications. This perspective article outlines the contemporary studies on fiber optic sensors founded on the sensing architecture of propagating as well as localized surface plasmon resonance. An in depth review of the prevalent analytical and surface chemical tactics involved in configuring the sensing layer over an optical fiber for the detection of various chemical and biological entities is presented. The involvement of nanomaterials as a strategic approach to enhance the sensor sensitivity is furnished concurrently providing an insight into the diverse geometrical blueprints for designing fiber optic sensing probes. Representative examples from the literature are discussed to appreciate the latest advancements in this potentially valuable research avenue. The article concludes by identifying some of the key challenges and exploring the opportunities for expanding the scope and impact of surface plasmon resonance based fiber optic sensors.", "author_names": [ "Banshi Dhar Gupta", "Ravi Kant" ], "corpus_id": 126413926, "doc_id": "126413926", "n_citations": 96, "n_key_citations": 1, "score": 0, "title": "[INVITED] Recent advances in surface plasmon resonance based fiber optic chemical and biosensors utilizing bulk and nanostructures", "venue": "", "year": 2018 }, { "abstract": "Abstract The Internet of Things (IoT) has witnessed exponential growth over the past decade and will significantly reshape human life from every aspect, e.g. defense, environmental monitoring, energy, food safety, knowledge dissemination, healthcare and so on. Fiber optic sensors, with both communication and sensing functions, have become a bridge to connect people and the whole world, so they are essential parts for accelerating the development of the IoT. Fiber optic sensors possess the capability of translating a change of target analyte into optical signals and subsequently transmit an optical signal with target analyte information to people, machines or systems in real time, even from a long distance. Therefore, exploration of high performance fiber optic chemical sensors and biosensors could significantly promote the development of the IoT. This review paper presents the foundations of fiber optic chemical sensing or biosensing, including the sensing mechanisms of various fiber optic sensors, sensing materials and the novel techniques for sensing materials deposition. Furthermore, recent developments on fiber optic chemical sensors and biosensors are summarized, analyzed and discussed. Finally, the strategies and guidelines to further promote the development of fiber optic sensors are also discussed.", "author_names": [ "Ming-Jie Yin", "Bobo Gu", "Quan-Fu An", "Chengbin Yang", "Yong Liang Guan", "Ken-Tye Yong" ], "corpus_id": 105477244, "doc_id": "105477244", "n_citations": 98, "n_key_citations": 1, "score": 0, "title": "Recent development of fiber optic chemical sensors and biosensors: Mechanisms, materials, micro/nano fabrications and applications", "venue": "", "year": 2018 }, { "abstract": "Author(s) Lindsey, NJ; Martin, ER; Dreger, DS; Freifeld, B; Cole, S; James, SR; Biondi, BL; Ajo Franklin, JB Abstract: (c)2017. American Geophysical Union. All Rights Reserved. Our understanding of subsurface processes suffers from a profound observation bias: seismometers are sparse and clustered on continents. A new seismic recording approach, distributed acoustic sensing (DAS) transforms telecommunication fiber optic cables into sensor arrays enabling meter scale recording over tens of kilometers of linear fiber length. We analyze cataloged earthquake observations from three DAS arrays with different horizontal geometries to demonstrate some possibilities using this technology. In Fairbanks, Alaska, we find that stacking ground motion records along 20 m of fiber yield a waveform that shows a high degree of correlation in amplitude and phase with a colocated inertial seismometer record at 0.8 1.6 Hz. Using an L shaped DAS array in Northern California, we record the nearly vertically incident arrival of an earthquake from The Geysers Geothermal Field and estimate its backazimuth and slowness via beamforming for different phases of the seismic wavefield. Lastly, we install a fiber in existing telecommunications conduits below Stanford University and show that little cable to soil coupling is required for teleseismic P and S phase arrival detection.", "author_names": [ "Nathaniel J Lindsey", "Eileen R Martin", "Douglas S Dreger", "Barry Freifeld", "Steve Cole", "Stephanie R James", "Biondo L Biondi", "Jonathan B Ajo-Franklin" ], "corpus_id": 133678278, "doc_id": "133678278", "n_citations": 151, "n_key_citations": 4, "score": 0, "title": "Fiber Optic Network Observations of Earthquake Wavefields: FIBER OPTIC EARTHQUAKE OBSERVATIONS", "venue": "", "year": 2017 }, { "abstract": "Abstract We present a U bent fiber optic SPR sensor based on the graphene/AgNPs, combined the virtues of graphene, AgNPs and U bent fiber. By changing the laser induced time, we achieved the optimal time for the deposition of AgNPs. With the proposed graphene/AgNPs U bent fiber optic sensor, we discussed and investigated the SPR behaviors. The shifts up to 32 and 16 nm are observed respectively for the detection of 90% aqueous ethanol and 20% aqueous glucose, corresponding refractive index (RI) 1.3657 and 1.3557. The sensitivity of this proposed is calculated as 1198 nm/RIU and the response and recovery time of this U bent fiber optic sensor are respectively 3 s and 80 s. These experimental results indicate that our proposed graphene/AgNPs U bent fiber optic sensor will be expected to open new avenue for the detection in the field of medicine, biotechnology and food safety.", "author_names": [ "C Zhang", "Zhe Li", "Shou Zhen Jiang", "Chong Li", "Shi Cai Xu", "Jing Yu", "Zhen Li", "Ming Hong Wang", "A H Liu", "Baoyuan Man" ], "corpus_id": 99527582, "doc_id": "99527582", "n_citations": 72, "n_key_citations": 1, "score": 0, "title": "U bent fiber optic SPR sensor based on graphene/AgNPs", "venue": "", "year": 2017 }, { "abstract": "Abstract Fiber optic distributed sensing, employing the Brillouin effect, is already a commercially available measurement technique for the accurate estimation of the static strain/temperature fields along tens of kilometers with a spatial resolution of the order of a meter. Furthermore, relentless research efforts are paving the way to even much wider usability of the technique through recently achieved enhanced performance in each of its critical dimensions: measurement range has been extended to hundreds of kilometers; spatial resolution is of the order of a centimeter or less, signal to noise ratio has been significantly improved; fast dynamic events can be captured at kHz's sampling rates; and a much better understanding of the underlying physics has been obtained, along with the formulation of figures of merit, and the preparation and early adoption of appropriate standards and guidelines. This paper describes the basics, as well as the state of the art, of the leading Brillouin interrogation methods, with emphasis on the significant progress made in the last 3 years. It also includes a short introduction to coding, which has proven instrumental in many of the recently obtained performance records.", "author_names": [ "Avi Motil", "Arik Bergman", "Moshe Tur" ], "corpus_id": 123924938, "doc_id": "123924938", "n_citations": 190, "n_key_citations": 8, "score": 0, "title": "[INVITED] State of the art of Brillouin fiber optic distributed sensing", "venue": "", "year": 2016 }, { "abstract": "This paper provides an overview of the different types of fiber optic sensors (FOS) that can be used with composite materials and also their compatibility with and suitability for embedding inside a composite material. An overview of the different types of FOS used for strain/temperature sensing in composite materials is presented. Recent trends, and future challenges for FOS technology for condition monitoring in smart composite materials are also discussed. This comprehensive review provides essential information for the smart materials industry in selecting of appropriate types of FOS in accordance with end user requirements.", "author_names": [ "Manjusha Ramakrishnan", "Ginu Rajan", "Yuliya Semenova", "Gerald Farrell" ], "corpus_id": 6242153, "doc_id": "6242153", "n_citations": 181, "n_key_citations": 2, "score": 0, "title": "Overview of Fiber Optic Sensor Technologies for Strain/Temperature Sensing Applications in Composite Materials", "venue": "Sensors", "year": 2016 }, { "abstract": "Distributed fiber optic vibration sensors receive extensive investigation and play a significant role in the sensor panorama. Optical parameters such as light intensity, phase, polarization state, or light frequency will change when external vibration is applied on the sensing fiber. In this paper, various technologies of distributed fiber optic vibration sensing are reviewed, from interferometric sensing technology, such as Sagnac, Mach Zehnder, and Michelson, to backscattering based sensing technology, such as phase sensitive optical time domain reflectometer, polarization optical time domain reflectometer, optical frequency domain reflectometer, as well as some combinations of interferometric and backscattering based techniques. Their operation principles are presented and recent research efforts are also included. Finally, the applications of distributed fiber optic vibration sensors are summarized, which mainly include structural health monitoring and perimeter security, etc. Overall, distributed fiber optic vibration sensors possess the advantages of large scale monitoring, good concealment, excellent flexibility, and immunity to electromagnetic interference, and thus show considerable potential for a variety of practical applications.", "author_names": [ "Xin Liu", "Bao-quan Jin", "Qing Bai", "Yu Wang", "Dong Wang", "Yuncai Wang" ], "corpus_id": 8349583, "doc_id": "8349583", "n_citations": 108, "n_key_citations": 1, "score": 0, "title": "Distributed Fiber Optic Sensors for Vibration Detection", "venue": "Sensors", "year": 2016 }, { "abstract": "We demonstrate a novel all fiber optic humidity sensor comprised of a WS2 film overlay on a side polished fiber (SPF) This sensor can achieve optical power variation of up to 6 dB in a relative humidity (RH) range of 35% 85% In particular, this novel humidity fiber sensor has a linear correlation coefficient of 99.39% sensitivity of 0.1213 dB/%RH, and a humidity resolution of 0.475%RH. Furthermore, this sensor shows good repeatability and reversibility, and fast response to breath stimulus. This WS2 based all fiber optic humidity sensor is easy to fabricate, is compatible with pre established fiber optic systems, and holds great potential in photonics applications such as in all fiber optic humidity sensing networks.", "author_names": [ "Yunhan Luo", "Chaoying Chen", "Kai Xia", "Shuihua Peng", "Heyuan Guan", "Jieyuan Tang", "Huiui Lu", "Jianhui Yu", "Jun Zhang", "Yi Xiao", "Zhe Chen" ], "corpus_id": 22298021, "doc_id": "22298021", "n_citations": 91, "n_key_citations": 1, "score": 0, "title": "Tungsten disulfide (WS2) based all fiber optic humidity sensor.", "venue": "Optics express", "year": 2016 } ]

[ { "abstract": "A parallel LLC series resonant converter with output voltage doubler is presented in this paper. The interleaved pulse width modulation (PWM) technique is adopted to reduce the ripple current on input and output capacitors. The capacitance of input and output capacitors can be reduced. The high current stress drawback of conventional LLC resonant converter is overcome by the proposed converter. Thus the adopted converter can be applied for high output current applications. Based on the series resonant behavior, all power switches are turned on at zero voltage switching (ZVS) and the rectifier diodes can be turned off at zero current switching (ZCS) Thus the switching losses on power semiconductors are reduced. In the output side, the voltage doubler topology is adopted for high output voltage applications. Compared with the conventional LLC converter, the advantages of the proposed circuit are low ripple currents on input and output terminals, small size and light weight of transformer, and low conduction losses on power semiconductors. In this paper, the principle of operation, steady state analysis and design consideration of the proposed converter are provided and discussed. In order to validate the proposed converter, the laboratory experiments with 24V/40A output for server power supply were provided.", "author_names": [ "B R Lin", "Wen-Ren Yang", "Jyun-Ji Chen", "Chien-Lan Huang", "Ming-Hung Yu" ], "corpus_id": 33735993, "doc_id": "33735993", "n_citations": 24, "n_key_citations": 0, "score": 1, "title": "Interleaved LLC series converter with output voltage doubler", "venue": "The 2010 International Power Electronics Conference ECCE ASIA", "year": 2010 }, { "abstract": "This paper proposes an interleaved Inductor Inductor Capacitor resonant converter with cascaded voltage doubler circuits for deeply depleted plug in electric vehicle battery charging. The use of voltage double circuits extends the operating range of converter by mitigating the effects of transformer's parasitic capacitors. The converter has two modes of operation: simultaneous and independent. In the former mode both interleaving converters operate together at the same frequency and in the later mode only one converter operates. In the former mode, it yields twofold higher gain compared to the later one. Thus, operation with combined mode changing and frequency control results in wider output voltage range. For confirmation, a laboratory prototype rated at input dc voltage of 400 V and output power of 1.5 kW is designed, and implemented. The results obtained from the prototype show that converter achieves a wide output voltage range of 100 420 V when operated in simultaneous mode with simple frequency control and an output voltage range of 50 100 V in the independent mode. With combined frequency and mode changing control, it achieves an output range of 50 420 V. The peak efficiency of converter was measured to be 95.65% at a peak power of 1.5 kW. Thus, the proposed converter is suitable for the dc dc stage of on board PEV battery charger.", "author_names": [ "M Imran Shahzad", "Shahid Iqbal", "Soib Taib" ], "corpus_id": 3500332, "doc_id": "3500332", "n_citations": 16, "n_key_citations": 1, "score": 0, "title": "Interleaved LLC Converter With Cascaded Voltage Doubler Rectifiers for Deeply Depleted PEV Battery Charging", "venue": "IEEE Transactions on Transportation Electrification", "year": 2018 }, { "abstract": "This paper proposes an LLC resonant converter with parallel series transformer connection and voltage doubler rectifier (PSVD LLC) i.e. LLC circuit structure in which the transformers are parallel series connected and the secondary side is voltage doubler rectifier. The parallel series connection can reduce the turns ratio of the transformer. And the use of the characteristics of the voltage doubler rectifier circuit improves the efficiency of the system, especially in the application of high frequency, low input voltage and high output voltage. This paper introduces the structure and working modes of the proposed circuit and analyzes the principle of how this circuit improves efficiency. A 1000W prototype of the proposed circuit is established to verify the effectiveness of the scheme.", "author_names": [ "Jiaxuan Zhou", "Hao Ma" ], "corpus_id": 201068789, "doc_id": "201068789", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Full Bridge LLC Resonant Converter with Parallel Series Transformer Connection and Voltage Doubler Rectifier", "venue": "2019 10th International Conference on Power Electronics and ECCE Asia (ICPE 2019 ECCE Asia)", "year": 2019 }, { "abstract": "Conventional frequency modulated LLC topology is unsuitable for ultrawide voltage range applications and suffers from poor voltage regulation performance at light load conditions. To cope with those issues, this article proposes a novel two phase dual LLC resonant converter. The primary side of the proposed converter is two paralleled half bridges LLC, and the transformers' secondary sides are in reverse series with shared full bridge rectifier. Both resonant tanks are driven by two fixed frequency square waves, whose frequencies are always tuned at the optimal resonant frequency. A phase shift is introduced between those two square waves to regulate the output voltage. The proposed topology demonstrates good voltage regulation performance, which is weakly dependent on the load condition. Zero voltage switching and zero current switching are well realized on the power mosfets and diodes in a wide range. A 1 kW rated laboratory prototype is designed to convert 390 V input to 10 420 V output. The prototype demonstrates a 98.1% peak efficiency and good voltage regulation capability. The experimental results agree well with the theoretical analysis.", "author_names": [ "Bo Xue", "Haoyu Wang", "Junrui Liang", "Qi Cao", "Zhiqing Li" ], "corpus_id": 221592161, "doc_id": "221592161", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Phase Shift Modulated Interleaved LLC Converter With Ultrawide Output Voltage Range", "venue": "IEEE Transactions on Power Electronics", "year": 2021 }, { "abstract": "The low transfer efficiency occurs in low line condition for general conventional power factor correction rectifier. This drawback can be improved by proposing Power Factor Correction (PFC) with voltage doubler characteristic and the topology can be seen on Salmon [1] and Maksimovic and Erickson [2] The Voltage doubler circuit applied in boost PFC converter to gain 400 V output was reported on Musavi et al. [3] However, PFC circuit should have multiple switches to realize function of double voltage in low line condition, it is not suitable for server power due to the issues of efficiency, reliability, and cost. Besides, the electric vehicle with plug in charging storage system can be charged through outside recycling system. The charging infrastructure always composes of AC/DC converter with power factor correction function in conjunction with series DC/DC buck converter structure. Preliminary stage AC/DC converter is important power stage module of electric vehicle (EV) battery charger as stated in Musavi et al. [3] is redrawn as Figure 1. The other literatures as Lai and Ho [4] Ryu et al. [5] Moon et al. [6] are the controlled the algorithm methodology related to EV application circuits and converters. The proposed PFC boost converter with voltage double characteristic improves efficiency of current interleave bridgeless PFC operated in low line and light load condition and meet input current harmonics specification as well. It can reach high power factor and high efficiency and suitable to apply for EV battery storage and charging system to have power reaching 3.4 kW. 2. OPERATING ANALYSIS", "author_names": [ "Chihchiang Hua", "Ching-Chun Chuang", "Hung-Chi Lee", "Chih-Wei Chuang", "Chuan-Ming Niu" ], "corpus_id": 219483954, "doc_id": "219483954", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research on a Bridgeless Interleaved PFC Boost Converter with Voltage Doubler Feature", "venue": "J. Robotics Netw. Artif. Life", "year": 2020 }, { "abstract": "A family of two phase interleaved LLC (iLLC) resonant converter with hybrid rectifier is proposed for wide output voltage range applications. The primary sides of the two LLC converters are in parallel, and the connection of the secondary windings in the two LLC converters can be regulated by the hybrid rectifier according to the output voltage. Variable frequency control is employed to regulate the output voltage and the secondary windings are in series when the output voltage is high. Fixed frequency phase shift control is adopted to regulate the configuration of the secondary windings as well as the output voltage when the output voltage is low. The output voltage range is extended by adaptively changing the configuration of the hybrid rectifier, which results in reduced switching frequency range, circulating current, and conduction losses of the LLC resonant tank. Zero voltage switching and zero current switching are achieved for all the active switches and diodes, respectively, within the entire operation range. The operation principles are analyzed and a 3.5 kW prototype with 400 V input voltage and 150 500 V output voltage is built and tested to evaluate the feasibility of the proposed method.", "author_names": [ "Hongfei Wu", "Xiaohai Zhan", "Yan Xing" ], "corpus_id": 21022601, "doc_id": "21022601", "n_citations": 74, "n_key_citations": 1, "score": 0, "title": "Interleaved LLC Resonant Converter With Hybrid Rectifier and Variable Frequency Plus Phase Shift Control for Wide Output Voltage Range Applications", "venue": "IEEE Transactions on Power Electronics", "year": 2017 }, { "abstract": "ABSTRACT High efficiency and simple structure are the main reasons for the widespread use of LLC converters. Nowadays, the application of LLC converters is still in development. In general, increasing the power level to use a parallel converter is quite popular. However, this method uses a separate transformer, which will lead to an obvious decrease in power density. Moreover, the separate transformer will also cause current imbalance due to the error of the magnetic material characteristic. Therefore, this study proposes an integrated transformer for a conventional interleaved LLC converter. This proposed structure can effectively increase the power density and decrease the problem of current imbalance. The operating principle of the interleaved LLC converter and an analysis of the integrated transformer are presented. Finally, experimental results are recorded for a prototype converter. The specifications are as follows: DC input voltage is 380 VDC, output voltage is 12 VDC, maximum output current is 50 A, output power is 600 W, and maximum conversion efficiency is approximately 95.5%", "author_names": [ "Yi-Feng Lin", "Chuanbiao Chen", "Zong-Xian Jiang", "Jing-Yuan Lin" ], "corpus_id": 235189554, "doc_id": "235189554", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Interleaved LLC half bridge series resonant converter with integrated transformer", "venue": "", "year": 2021 }, { "abstract": "An Interleaved Voltage Doubler Boost Converter (IVDBC) using digitalized average current control to achieve Power Factor Correction (PFC) is proposed in this paper. The basic circuit configuration of proposed IVDBC is a two phase interleaved boost converter and a full wave voltage doubler rectifier in series. The capacitors of the voltage doubler circuit are charged alternately by the two phase interleaved operation; therefore, the voltage conversion gain of the IVDBC is twice that of a conventional interleaved boost converter. Consequently, the proposed IVDBC is probable to be used for high voltage applications. A TI TMS320F28335 is used in this paper to design and implement the average current control scheme for the IVDBC. A prototype circuit with an AC input voltage of 110V, DC output voltages between 400V to 700V and a rated output current of 1.4A is realized in this paper. Experimental results indicate that the Total Harmonic Distortion (THD) and power factor of input current of the proposed IVDBC for PFC can conform the requirements of international regulations. Besides, a maximum conversion efficiency of 94.07% can be achieved.", "author_names": [ "Bo-Jia Huang" ], "corpus_id": 53080794, "doc_id": "53080794", "n_citations": 5, "n_key_citations": 1, "score": 0, "title": "Interleaved Voltage Doubler Boost Converter for Power Factor Correction", "venue": "2018 International Power Electronics Conference (IPEC Niigata 2018 ECCE Asia)", "year": 2018 }, { "abstract": "A new interleaved high step up isolated DC DC converter with zero voltage switching (ZVS) is proposed in this paper. The configuration is composed of the active clamp circuits and voltage doubler circuits with parallel input series output structure. The active clamp circuits are used to achieve ZVS performance for the power switches such that the switching losses are reduced. The voltage doubler circuits are used to obtain high voltage gain. The voltage stresses on the power switches are greatly lower than the output voltage such that the low voltage rated MOSFETs with low on resistances can be adopted to reduce the conduction losses. The input ripple current is reduced by the interleaved operation. The energy stored in leakage inductances of the coupled inductors is recycled to avoid the voltage spike on the main switches. The operating principle and steady state analysis of the proposed converter are presented in detail. Finally, a 1000 W prototype converter with 36 V input and 380 V output is built and tested in the laboratory. The experimental results are presented to validate the feasibility and the performance of the proposed converter.", "author_names": [ "Shin-Ju Chen", "Shang-Yi Yang" ], "corpus_id": 227063103, "doc_id": "227063103", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Analysis and Implementation of An Interleaved High Step Up Isolated DC DC Converter with Zero Voltage Switching", "venue": "IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society", "year": 2020 }, { "abstract": "This paper presents a tightly regulated multi output isolated converter that employs only an independently regulated synchronous Single Switched Post Regulator (SSPR) The proposed converter is a highly accurate single ended secondary side post regulator based on a Series Resonant Converter (SRC) furthermore, it has a voltage doubler characteristic. The proposed post regulator requires only one auxiliary switch, in contrast with a bulky and expensive non isolated DC DC converter. Moreover, the added voltage doubler can tightly regulate the slave output current. In addition, the voltage doubler can improve electromagnetic interference characteristics and reduce switching losses arising from the Zero Current Switching (ZCS) operation of all power switches. The validity of the proposed converter is verified using experimental results obtained via a prototype converter applicable to an LED 3D TV power supply.", "author_names": [ "Sang Gab Park", "Byoung-Kuk Lee", "Jong-Soo Kim" ], "corpus_id": 225275361, "doc_id": "225275361", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Optimal Design of Multi Output LLC Resonant Converter with Independently Regulated Synchronous Single Switched Power Regulator", "venue": "", "year": 2020 } ]

[ { "abstract": "Unconventional thermo optic responses of CH3NH3PbCl3 enable phase shift compensators and tunable retarders for visible light. Lead halide perovskites are promising semiconductors for high performance photonic devices. Because the refractive index determines the optimal design and performance limit of the semiconductor devices, the refractive index and its change upon external modulations are the most critical properties for advanced photonic applications. Here, we report that the refractive index of halide perovskite CH3NH3PbCl3 shows a distinct decrease with increasing temperature, i.e. a large negative thermo optic coefficient, which is opposite to those of conventional inorganic semiconductors. By using this negative coefficient, we demonstrate the compensation of thermally induced optical phase shifts occurring in conventional semiconductors. Furthermore, we observe a large and slow refractive index change in CH3NH3PbCl3 during photoirradiation and clarify its origin to be a very low thermal conductivity supported by theoretical analysis. The giant thermo optic response of CH3NH3PbCl3 facilitates efficient phase modulation of visible light.", "author_names": [ "Taketo Handa", "Hirokazu Tahara", "Tomoko Aharen", "Yoshihiko Kanemitsu" ], "corpus_id": 198120457, "doc_id": "198120457", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Large negative thermo optic coefficients of a lead halide perovskite", "venue": "Science Advances", "year": 2019 }, { "abstract": "Abstract Chalcogenide glasses have attracted much attention for the realization of photonic components owing to their outstanding optical properties in the mid infrared (MIR) region. However, relatively few refractive index dispersion data are presently available for these glasses at MIR wavelengths. This paper presents a mini review of methods we have both used and developed to determine the refractive indices and thermo optic coefficients of chalcogenide glasses at MIR wavelengths, and is supported by new results. The mini review should be useful to both new and established researchers in the chalcogenide glass field and fields of MIR optics, fiber optics and waveguides. Three groups of methods are distinguished: (1) spectroscopic ellipsometry, (2) prism based methods, and (3) methods using Fourier transform infrared (FTIR) transmission data. The mini review is supported by a brief discussion of refractive index models.", "author_names": [ "Y Fang", "David Furniss", "Dinuka Jayasuriya", "Harriet Parnell", "Z Q Tang", "Daniel J Gibson", "Shyam S Bayya", "Jas S Sanghera", "Angela B Seddon", "T M Benson" ], "corpus_id": 202983186, "doc_id": "202983186", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "(INVITED) Methods for determining the refractive indices and thermo optic coefficients of chalcogenide glasses at MIR wavelengths", "venue": "Optical Materials: X", "year": 2019 }, { "abstract": "A new method (FTIR continuous dn dT method, n is refractive index and T temperature) for measuring the continuous thermo optic coefficients of thin transparent films in the mid infrared (MIR) spectral region is introduced. The technique is based on Fourier transform infrared (FTIR) transmission spectra measured at different temperatures. It is shown that this method can successfully determine the thermo optic coefficient of chalcogenide glass thin films (of batch compositions Ge20Sb10Se70 at. (atomic and Ge16As24Se15.5Te44.5 at. over the wavelength range from 2 to 25 um. The measurement precision error is less than 11.5 ppm degC over the wavelength range from 6 to 20 um. The precision is much better than that provided by the prism minimum deviation method or an improved Swanepoel method.", "author_names": [ "Yuanrong Fang", "David Furniss", "Dinuka Jayasuriya", "Harriet Parnell", "Zhuoqi Tang", "Angela B Seddon", "Trevor M Benson" ], "corpus_id": 199686852, "doc_id": "199686852", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Determining the continuous thermo optic coefficients of chalcogenide glass thin films in the MIR region using FTIR transmission spectra.", "venue": "Optics express", "year": 2019 }, { "abstract": "Abstract Terahertz time domain spectroscopy has been used to measure the temperature dependent absorption coefficients and refractive indices of different polymers in 0.2 1.8 THz spectral frequency. The coefficients of temperature dependent Sellmeier equation for all these polymers have also been evaluated by statistical fitting the measured data, which will be helpful for the evaluation of dispersion properties of the material. Additionally, the thermo optic coefficients have been evaluated to be the range of 1.230 x 10 4 to 2.50 x 10 4 K 1 for 298 373 K. This data would be helpful for the applications of polymers as THz waveguide and other temperature sensitive devices. These results provide a temperature dependent database of optical properties of different polymers for their efficient utilization in THz technology.", "author_names": [ "Muhammad Bilal Mumtaz", "M Ahsan Mahmood", "Sabih D Khan", "M Aslam Zia", "Mushtaq Ahmed", "Izhar Ahmad" ], "corpus_id": 109294660, "doc_id": "109294660", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Experimental measurement of temperature dependent sellmeier coefficients and thermo optic coefficients of polymers in terahertz spectral range", "venue": "Optical Materials", "year": 2019 }, { "abstract": "The values of dn/dT for thermally evaporated WO3 thin films were found to be negative either in the heating cycle (295 373 K) or in the cooling cycle (100 300 K) and were found to be of order of 10 5 K 1. On the other hand thermo optic coefficients (TOCs: dn/dT and dk/dT values) of tungsten bronzes (H+ Li+ Na+ with different concentrations were found to be positive and negative, respectively in both the heating and cooling cycles and they were found to be in the order of 10 4 K 1. Heating cycles show hysteresis loops of n and k for tungsten bronzes, which are good for electrochromic devices. On heating the bronzes at temperature higher than 400 K, there might be a reduction in the porosity but an irreversible disordering of hydrogen, lithium or sodium atoms could occur because of anomalous dispersions produced in the optical data. For cooling cycles, the calculated TOCs were again of the order of 10 4 but there was an increase in dn/dT and a decrease in dk/dT values due to more amorphousness built up in the bronzes during the cooling cycles. This change in the values of TOCs for tungsten bronzes created small decrease in electronic polarizabilities (ae) which were calculated in the range from 8.003 to 8.02 x 10 24 cm3 in the cooling cycles.", "author_names": [ "Zahid Hussain" ], "corpus_id": 204196693, "doc_id": "204196693", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Thermo Optic Coefficients and Electronic Polarizabilities of Tungsten Bronzes Using Ellipsometry", "venue": "IEEE Photonics Journal", "year": 2019 }, { "abstract": "We have measured mass densities, thermo optic coefficients, and electronic polarizability of MoO3 thin films and of HxMoO3 and LixMoO3 bronze thin films over the temperature range from 100 K to 373 K using ellipsometry. The mass densities of MoO3 and molybdenum bronzes with different concentrations (x) changed from 3.76 g/cm3 to 2.45 g/cm3 during the heating and cooling cycles. Thermo optic coefficients (TOCs) or dn/dT and dk/dT values of the molybdenum bronzes were found to have anomalous dispersion in the heating cycles over the range 295 373 K. On the other hand, the values of dn/dT for MoO3 thin films and for ZxMoO3 bronzes were found to be negative and positive, respectively over the temperature range 100 295 K and were on the order of 10 4 K 1. The respective values of dk/dT were found to be positive and negative and were on the order of 10 4 K 1 in the same temperature range. A little increase in the values of TOCs for the molybdenum bronzes is due to small increase in electronic polarizability, which was calculated in the range from 8.20 to 8.22 x 10 24 cm3 over the temperature range 100 373 K. All these small values are due to creation of more amorphousness in the MoO3 structure during the cooling cycles. The n and k data and TOCs values of molybdenum bronzes are explained using analytical model. The reported ellipsometric data is also interpreted in terms of small polarons and bipolarons using configurational coordinate model.", "author_names": [ "Zahid Hussain" ], "corpus_id": 201656267, "doc_id": "201656267", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Ellipsometric Investigations of Electronic Polarizability and Thermo optic Coefficients of ZxMoO3 (Z H+ Li+ Bronzes", "venue": "Journal of Electronic Materials", "year": 2019 }, { "abstract": "Abstract The development of thermo optic modulator elements for midwave infrared (MWIR) and longwave infrared (LWIR) electro optic systems, and the development of resistive thermometer elements for infrared imaging microbolometers require materials with high thermo optic coefficients (TOC) and high temperature coefficients of resistance (TCR) respectively. In this paper, we synthesize novel vanadium oxide (VxOy) thin film structures and measure their MWIR/LWIR thermo optic coefficients (TOCs) and their temperature coefficients of resistance (TCRs) The VxOy thin film are synthesized by sputter depositing interchanging, 5 nm thick, layers of vanadium sesquioxide (V2O3) and vanadium (V) reaching a final thin film thickness of 95 nm. The sputter deposited multilayer structures are then ex situ annealed in N2 and O2 atmospheres at 300 degC for 30 min. Infrared spectroscopic ellipsometry was used to measure the optical constants of the thin films as a function of temperature across the MWIR and LWIR bands (3000 14000 nm) The synthesized VxOy thin films exhibited high TOCs and high TCRs when operated in their semiconducting phase. A high TOC was measured reaching a maximum of 0.0278 degC 1 and 0.119 degC 1 at l 4000 nm for N2 and O2 annealed VxOy thin films respectively; and reaching a maximum of 0.0634 degC 1 and 0.139 degC 1 at l 10,000 nm for N2 and O2 annealed VxOy thin films respectively. Moreover, sheet resistance versus temperature measurements were conducted revealing room temperature sheet resistances of 1.495 k O/sq. and 1.516 k O/sq. and TCRs of 3.54%/degC and 3.46%/degC for N2 and O2 annealed VxOy thin films respectively.", "author_names": [ "Mohamed R Abdel-Rahman" ], "corpus_id": 125974018, "doc_id": "125974018", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Vanadium oxide thin films with high midwave longwave infrared thermo optic coefficients and high temperature coefficients of resistance", "venue": "", "year": 2018 }, { "abstract": "A microcavity fiber Fabry Perot interferometer (MFFPI) that is based on dual hollow core fibers (HCFs) is developed for measuring the thermo optic coefficients (TOCs) of liquids. The proposed MFFPI was fabricated by fusion splicing a tiny segment of the main HCF with a diameter D of 30 mm and another section of feeding HCF with a diameter of 5 mm. Then, the main HCF was filled with liquid by capillary action through the feeding HCF by immersing the MFFPI in the liquid. The TOCs of the Cargille liquid (n(D)=1.3) deionized (DI) water, and ethanol were accurately determined from the shift of the interference wavelength, which was due to the temperature variation. Our experimental results were also compared with other published studies to investigate the effectiveness of the proposed sensing scheme. The major advantage is that the miniature MFFPI can achieve the measurement of the TOCs of the liquids with picoliter volume, and the measured liquids also can be sealed off and stored inside the HCF to prevent contamination.", "author_names": [ "Cheng-Ling Lee", "Hsuan-Yu Ho", "Jheng-Hong Gu", "Tung-Yuan Yeh", "Chung-Hao Tseng" ], "corpus_id": 36465809, "doc_id": "36465809", "n_citations": 46, "n_key_citations": 1, "score": 0, "title": "Dual hollow core fiber based Fabry Perot interferometer for measuring the thermo optic coefficients of liquids.", "venue": "Optics letters", "year": 2015 }, { "abstract": "We report a method for compensation of errors caused by temperature fluctuations in refractive index measurements using Silicon photonic microring sensors. The method involves determination of resonance wavelength shifts caused by thermal fluctuations using real time measurement of on chip temperature variations and thermo optic coefficient (TOC) of analyte liquids. Resistive metal lines patterned around Silicon microrings are used to track temperature variations and TOC of analyte is calculated by measuring wavelength shifts caused by controlled increments in device temperature. The TOC of de ionized water is determined to be 1.12 x 10 4/degC, with an accuracy of 8.26 x 10 6/degC. In our system, chip surface temperature variations were measured with an instrument limited precision of 0.004 degC yielding a factor of 16 enhancement in tracking accuracy compared to conventional, bottom of chip temperature measurement. We show that refractive index detection limit of the microring sensor is also improved by the same factor.", "author_names": [ "Prashanth R Prasad", "Shankar Kumar Selvaraja", "Manoj M Varma" ], "corpus_id": 44137328, "doc_id": "44137328", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Real time compensation of errors in refractive index shift measurements of microring sensors using thermo optic coefficients.", "venue": "Optics express", "year": 2018 }, { "abstract": "Seventeen glasses in the Ge As Se ternary glass forming region have been fabricated and analyzed to provide input for optical design data and to establish composition and structure based relationships to aide development of novel chalcogenide glasses with tailored optical functionality. While known that Ge addition to binary As Se glasses enhances the mean coordination number (MCN) of the network and results in increased Tg and decreased CTE, this work highlights the impact on optical properties, specifically mid wave (l 4.515 mm) index and thermo optic coefficient (dn/dT) Trends in property changes were correlated with an excess or deficiency of chalcogen content in the glassy network as compared to stoichiometric compositions. Transitions in key optical properties were observed with the disappearance of Se Se homopolar bonds and creation of As As homopolar bonds which are associated with the Se rich and Se deficient regions near the stoichiometry, respectively. A second transition was observed with the creation of GeSe ethane like structures, which are only present in strongly Se deficient networks. Fitting dn/dT values with a simplified version of the thermal Lorentz Lorenz formulation yielded a linear relation between the quantity (n 3dn/dT) and the CTE, which can be used to predict compositions with the near zero dn/dT required for athermal optical systems.", "author_names": [ "Benn Gleason", "Kathleen Richardson", "Laura Sisken", "Charmayne E Smith" ], "corpus_id": 139079603, "doc_id": "139079603", "n_citations": 32, "n_key_citations": 1, "score": 0, "title": "Refractive Index and Thermo Optic Coefficients of Ge As Se Chalcogenide Glasses", "venue": "", "year": 2016 } ]

[ { "abstract": "Introduction In today's business climate, continuous i n n ova t i o n a n d p ro d u c t i v i t y improvements are essential to the survival of any company. In the semiconductor industry, productivity improvement is generally accomplished using decreased cost per function, economy of scale, increased wafer diameter, process simplification and yield enhancement. The challenges for extreme edge dies increased with the conversion from 200mm to 300mm wafer processing, and will be further increased by the transition to 450mm [3] Increasingly sophisticated and more expensive equipment is required for technology shrinks, making the acquisition of funds for capacity expansion ever more difficult. Process simplification can only be done to a certain extent. Emphasis is therefore placed on fast yield learning, which claims the biggest financial leverage. Due to the narrower process windows at smaller technology nodes, centerto edge uniformity over the wafer is crucial for yield [4] Consequently, wafer edge and bevel induced yield loss were introduced as critical elements to the International Technology Roadmap for Semiconductors (ITRS) in 2005 and are still considered challenging [5, 6] The ITRS also highlights the importance of r im problems in the wafer edge exclusion guideline. A recent repor t descr ibed the economically optimized technology transfer and ramp methodology from development to a mass production site within a global fabrication cluster [7] This paper outlines the wafer edge yield engineering methodology, which was essential for the reported steep production ramp.", "author_names": [ "Oguz Yavas", "Ernst-christian Richter", "Christian Kluthe", "Markus Sickmoeller" ], "corpus_id": 13591736, "doc_id": "13591736", "n_citations": 4, "n_key_citations": 0, "score": 1, "title": "Wafer edge yield engineering in leading edge DRAM manufacturing", "venue": "", "year": 2009 }, { "abstract": "In leading edge patterning processes, overlay is now entangled with CD including OPC residuals and stochastics. This combined effect is a serious challenge for continued shrink and can be characterized with an Edge Placement Error (EPE) budget containing multi domain components: global and local CD, local placement errors, overlay errors, etch biases and OPC. EPE defines process capability and ultimately relates to device yield. Understanding the EPE budget leads to efficient ways to monitor process capability and optimize it using EPE based process control applications. We examine a critical EPE use case on a leading edge DRAM node. We start by constructing and verifying the EPE Budget via densely sampled on product in device local, global CD and Overlay metrology after the etch process step. EPE budget contributors are ranked according to their impact to overall EPE performance and later with simulated EPE performance improvements per component. A cost/benefit analysis is shown to help choose the most HVM friendly solutions.", "author_names": [ "Jaeseung Jeong", "Jinho Lee", "Jinsun Kim", "Sun Young Yea", "Chan Hwang", "Seung Yoon Lee", "Jeongjin Lee", "Joonsoo Park", "Peter Nikolsky", "Daniel Park", "Antonio Corradi", "Hyun-Woo Yu", "Sunji Jung", "Denis Ovchinnikov", "Vadim Timoshkov", "Isabel de la Fuente Valentin", "Yuxiang Yin", "Kaustubh Padhye", "Wim Tjibbo Tel", "Harm Dillen", "Koen Thuijs", "Daan Slotboom", "Miao Wang", "Rhys Su", "Marc Kea", "Jin-Woo Lee", "Yun-a Sung", "Sang-Uk Kim", "Youngjo Song", "James Lee", "Oh-Sung Kwon" ], "corpus_id": 215789935, "doc_id": "215789935", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Understanding advanced DRAM edge placement error budget and opportunities for control", "venue": "Advanced Lithography", "year": 2020 }, { "abstract": "High Performance Computing systems can employ leading edge Heterogeneous Integration (HI) technology including Fan Out Wafer Level Packaging (FOWLP) and high density Redistribution Layers (RDL) to maximize system bandwidth and performance. These More than Moore strategies are growing in importance and present unique challenges that must be overcome to enable mainstream adoption. FOWLP roadmaps for interconnections between SoC (System on Chip) and DRAM (Dynamic Random Access Memory) split die FPGA (Field Programmable Gate Array) and image sensors and SoC are driving RDL scaling and aggressive FOWLP processes are targeting $0.8\\ \\mu \\mathrm{m} design rules. High resolution lithography is required for high density, fine RDL applications and the main lithography challenge is to provide a large Depth of Focus (DoF) to reliably pattern sub micron RDL traces across a large exposure field. This paper details an analysis of candidate optical conditions for sub micron imaging including data demonstrating the DoF performance of an optimized lithography system (stepper) To meet the high resolution requirements of fine RDL processes, Canon developed the FPA 5520iV HR [20iV HR] i line stepper that employs a new projection optical system featuring a maximum 0.24 Numerical Aperture (NA) and a 52 x 34 mm field size. We will present data illustrating that 0.24 NA steppers can provide excellent resolution and pattern fidelity throughout each exposure field across the entire wafer. High density FOWLP wafers can also display extreme die shift, warpage and topography that must be addressed to enable high yield and high productivity processes. Die placement error in FOWLP wafers creates orders of magnitude more alignment error versus traditional silicon wafers and advanced alignment compensation is required to improve overlay matching. Alignment solutions for processing distorted FOWLP wafers include the Grid PA system that automatically corrects the wafer loading position based on die grid sampling, and Enhanced Advanced Global Alignment (EAGA) that allows the stepper to measure and compensate for shift, rotation and intra field magnification errors on a die by die basis. FOWLP reconstituted wafers can also experience large warpage that can decrease productivity and DoF and to combat these challenges, our steppers have been designed to handle wafers with over 5 mm of warpage and are also based on a Front End Of the Line (FEOL) stepper platform that offers die by die tilt and focus measurement and compensation to maximize focus accuracy and DoF. This paper provides an analysis of key lithography challenges facing aggressive FOWLP and fine RDL processes details of stepper technology that helps enable high density integration in mass production. We remain committed to enabling innovation through lithography system performance upgrades and development of original options supporting current and future FOWLP and fine RDL processes.", "author_names": [ "Doug Shelton", "Ken-ichiro Mori", "Yoshio Goto", "Hiromi Suda" ], "corpus_id": 208631766, "doc_id": "208631766", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solutions for Advanced Heterogeneous Integrtion and Fan Out Processes", "venue": "2019 International Wafer Level Packaging Conference (IWLPC)", "year": 2019 }, { "abstract": "As device sizes continue to increase on devices at 2x nm design rule and beyond and high wafer stress is worsening due to multi film stacking in the vertical memory process, we observe an increasing trend in edge yield issues worldwide. Wafer edge inspection and metrology become thus critical to drive root cause analysis for improving the yield during a new technology ramp. Nowadays, wafer defectivity correlation to edge is also key for production monitoring, but not without challenges due to the diverse sensitivity demands for the wafer front side, as compared to the wafer edge and back side. In this paper we are able to demonstrate that a cluster inspection platform with the proper balance of sensitivity and throughput is a key enabler for production monitoring. The study required high resolution imaging of the wafer front side, accurate metrology and defect binning capability at the wafer edge, and unique capability to isolate issues that matter in the wafer backside all in a single inspection cluster tool platform. This setup allows for faster time to decisions and eliminates the need to rely on other sources of inspection data. We present several examples of defectivity correlation between the wafer edge and both front and back side, with scanning electron microscope (SEM) examples showing same defect types captured. The root cause for edge defectivity is very often found to be in the crossover of edge bead removal (EBR) lines from successive steps. High quality and accurate EBR metrology is thus essential on many process steps including on backend layers where many EBR lines are found and need to be distinguished. Likewise, anomalies in metrology data of the edge profile can also act as an important indicator of possible defectivity on the wafer. Keywords Wafer Edge, Inspection, Metrology, Defect correlation, Root cause analysis", "author_names": [ "Tae-Heon Kim", "Jaehyoung Oh" ], "corpus_id": 186202217, "doc_id": "186202217", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Criticality of Wafer Edge Inspection and Metrology Data to All Surface Defectivity Root Cause and Yield Analysis", "venue": "", "year": 2016 }, { "abstract": "A novel 65nm Dynamic Random access memory (DRAM) cell, namely capacitor less RectFET based DRAM cell (CLRDC) is explored in silicon on insulator (SoI) wafer for embedded DRAM (eDRAM) for system on chip (SoC) applications with Rectangular FET (RectFET) as its pass transistor (PT) This CLRDC exploits its parasitic surround buried oxide capacitance (SBC) of SoI wafer around RectFET (source) for realizing its 'charge storage capacitance (Cs) For Cs=30fF (femtoFarad) target, it's found to need an area factor of 4.3um2 with 5nm thick SoI buried oxide. This SoI wafer is explored to yield a capacitance density Cbuox=6.91 fF/um2. The DC parameters of the PT are found to be very sensitive to process anneal temperature (Ta) and so are its DC characteristics too. A 2% increase in the Ta from a nominal 1000oC has resulted in an increase of 30% and 1.1% in the RectFET's leakage (Idsat off=I off) and on state (Idsat on=I on) currents respectively. The CLRDC cell transfer ratio T is also found to be a function of small signal frequency (f) Ta, and source/drain bias voltages Vs/Vd, respectively. And finally the retention characteristics of this CLRDC is again found to be a function of I off and I on currents of RectFET, when studied at RectFET's (drain) supply voltage VDD=1.2V.", "author_names": [ "G Malleshaiah", "H C Srinivasaiah" ], "corpus_id": 117662363, "doc_id": "117662363", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Novel DRAM Cell Structure with Parasitic Storage Capacitance for SoCs on SoI Wafer in 65nm Planar MOS Technology", "venue": "", "year": 2018 }, { "abstract": "This article discusses the transition of a form of nanoimprint lithography technology, known as Jet and Flash Imprint Lithography (J FIL) from research to a commercial fabrication infrastructure for leading edge semiconductor integrated circuits (ICs) Leading edge semiconductor lithography has some of the most aggressive technology requirements, and has been a key driver in the 50 year history of semiconductor scaling. Introducing a new, disruptive capability into this arena is therefore a case study in a \"high risk high reward\" opportunity. This article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry, novel research ideas being explored, and literature in nanoimprint lithography. The article then focuses on the J FIL process, and the interdisciplinary nature of risk, involving nanoscale precision systems, mechanics, materials, material delivery systems, contamination control, and process engineering. Next, the article discusses the strategic decisions that were made in the early phases of the project including: (i) choosing a step and repeat process approach; (ii) identifying the first target IC market for J FIL; (iii) defining the product scope and the appropriate collaborations to share the risk reward landscape; and (iv) properly leveraging existing infrastructure, including minimizing disruption to the widely accepted practices in photolithography. Finally, the paper discusses the commercial J FIL stepper system and associated infrastructure, and the resulting advances in the key lithographic process metrics such as critical dimension control, overlay, throughput, process defects, and electrical yield over the past 5 years. This article concludes with the current state of the art in J FIL technology for IC fabrication, including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.", "author_names": [ "S V Sreenivasan" ], "corpus_id": 115951465, "doc_id": "115951465", "n_citations": 72, "n_key_citations": 0, "score": 0, "title": "Nanoimprint lithography steppers for volume fabrication of leading edge semiconductor integrated circuits", "venue": "Microsystems nanoengineering", "year": 2017 }, { "abstract": "Single crystal silicon has played the fundamental role in electronic industry since the second half of the 20th century and still remains the most widely used material. Electronic devices and integrated circuits are fabricated on single crystal silicon wafers which are produced from silicon crystals grown primarily by the Czochralski (CZ) technique. Various defects are formed in the growing crystal as well as in the wafers during their processing. This chapter deals with the topic of engineering of crystal defects in the technology of manufacturing silicon single crystals and silicon wafers for the electronic industry. A basic overview of crystal defects found in semiconductor grade silicon is provided and mechanisms of their formation are introduced. The impact of crystal defects on the manufacturing and performance of electronic devices is outlined and some of the methods of defect analyses are described. Finally, the most important methods for control of defect formation are summarized.", "author_names": [ "Lukas Valek", "Jan Sik" ], "corpus_id": 10545067, "doc_id": "10545067", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Defect Engineering During Czochralski Crystal Growth and Silicon Wafer Manufacturing", "venue": "", "year": 2012 }, { "abstract": "Cutting edge high performance systems demand larger and denser processors, but future lithographic nodes are expected to introduce higher manufacturing costs and yield challenges. Die level integration technologies like passive interposer based 2.5D have demonstrated the potential for cost reductions through die partitioning and yield improvement, but system performance and scalability may be impacted. Alternatively, active interposer technology, the intersection of 3D and 2.5D methodologies, can provide higher performance interconnect networks to integrate chiplets, but the active interposer die is itself subject to cost and yield concerns. In this work, we perform a cost and performance comparison between traditional monolithic 2D SoCs, 2.5D passive interposers, and 2.5D/3D active interposers to demonstrate the trade offs between the interposer types for current and future high performance systems. This work introduces a multi die core binning cost model to demonstrate the yield improvements from interposer based die partitioning of large multi core processors. The relative cost and performance scaling trade offs of passive and active interposer dies are then compared for the target systems, demonstrating that both methodologies can indeed provide cost effective integration for different system requirements. Finally, this work demonstrates how the extra \"prepaid\" silicon area of the interposers can be leveraged for fault tolerance to improve yield and cost effectiveness. In summary, this work concludes that both active and passive interposers can cost effectively improve the functional and parametric yield of high performance systems, together providing a cost versus performance space to meet a range of design requirements.", "author_names": [ "Dylan Stow", "Yuan Xie", "Taniya Siddiqua", "Gabriel H Loh" ], "corpus_id": 464106, "doc_id": "464106", "n_citations": 34, "n_key_citations": 3, "score": 0, "title": "Cost effective design of scalable high performance systems using active and passive interposers", "venue": "2017 IEEE/ACM International Conference on Computer Aided Design (ICCAD)", "year": 2017 }, { "abstract": "Semiconductor industry has increasingly resorted to strain as a means of realizing the required node to node transistor performance improvements. Straining silicon fundamentally changes the mechanical, electrical (band structure and mobility) and chemical (diffusion and activation) properties. As silicon is strained and subjected to high temperature thermal processing, it undergoes mechanical deformations that create defects, which may significantly limit yield. Engineers have to manipulate these properties of silicon to balance the performance gains against defect generation. This paper will elucidate the current understanding and ongoing published efforts on all these critical properties in bulk strained silicon. The manifestation of these properties in CMOS transistor performance and designs that successfully harness strain is reviewed in the last section. Current manufacturable strained silicon technologies are reviewed with particular emphasis on scalability. A detailed case study on recessed silicon germanium transistors illustrates the application of the fundamentals to optimal transistor design.", "author_names": [ "Periannan Chidambaram", "C Bowen", "S Chakravarthi", "Charles F Machala", "R Wise" ], "corpus_id": 22920522, "doc_id": "22920522", "n_citations": 145, "n_key_citations": 1, "score": 0, "title": "Fundamentals of silicon material properties for successful exploitation of strain engineering in modern CMOS manufacturing", "venue": "IEEE Transactions on Electron Devices", "year": 2006 }, { "abstract": "Moore's law in the semiconductor industry came to mean regular, predictable introductions of new manufacturing technology that enabled denser electronics. Adoption of new manufacturing technology, and its effect on silicon wafer processing costs, determined how rapidly transistor manufacturing costs declined. In recent years, both cost decline rates and other economically valuable technical benefits flowing from use of the newest chip making technology seem to have substantially diminished.", "author_names": [ "Kenneth Flamm" ], "corpus_id": 577450, "doc_id": "577450", "n_citations": 14, "n_key_citations": 1, "score": 0, "title": "Has Moore's Law Been Repealed? An Economist's Perspective", "venue": "Computing in Science Engineering", "year": 2017 } ]

[ { "abstract": "Rapid expansion of the solar photovoltaic (PV) industry is quickly causing solar to play a growing importance in the energy mix of the world. Over the full life cycle, although to a smaller degree than traditional energy sources, PV also creates solid waste. This paper examines the potential need for PV recycling policies by analyzing existing recycling protocols for the five major types of commercialized PV materials. The amount of recoverable semiconductor material and glass in a 1 m2 area solar module for the five types of cells is quantified both physically and the profit potential of recycling is determined. The cost of landfill disposal of the whole solar module, including the glass and semiconductor was also determined for each type of solar module. It was found that the economic motivation to recycle most PV modules is unfavorable without appropriate policies. Results are discussed on the need to regulate for appropriate energy and environmental policy in the PV manufacturing industry particularly for PV containing hazardous materials. The results demonstrate the need to encourage producer responsibility not only in the PV manufacturing sector, but also the entire energy industry.", "author_names": [ "Nicole C McDonald", "Joshua M Pearce" ], "corpus_id": 111353593, "doc_id": "111353593", "n_citations": 127, "n_key_citations": 5, "score": 1, "title": "Producer Responsibility and Recycling Solar Photovoltaic Modules", "venue": "", "year": 2010 }, { "abstract": "This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out as the best candidates for either single PV module or multiple PV module applications.", "author_names": [ "S B Kjaer", "John Kim Pedersen", "Frede Blaabjerg" ], "corpus_id": 14278578, "doc_id": "14278578", "n_citations": 3470, "n_key_citations": 151, "score": 0, "title": "A review of single phase grid connected inverters for photovoltaic modules", "venue": "IEEE Transactions on Industry Applications", "year": 2005 }, { "abstract": "Environmental regulations can have a significant impact on product use, disposal, and recycling. This report summarizes the basic aspects of current federal, state and international regulations which apply to end of life photovoltaic (PV) modules and PV manufacturing scrap destined for disposal or recycling. It also discusses proposed regulations for electronics that may set the ground of what is to be expected in this area in the near future. In the US, several states have started programs to support the recycling of electronic equipment, and materials destined for recycling often are excepted from solid waste regulations during the collection, transfer, storage and processing stages. California regulations are described separately because they are different from those of most other states. International agreements on the movement of waste between different countries may pose barriers to cross border shipments. Currently waste moves freely among country members of the Organization of Economic Cooperation and Development (OECD) and between the US and the four countries with which the US has bilateral agreements. However, it is expected, that the US will adopt the rules of the Basel Convention (an agreement which currently applies to 128 countries but not the US) and that the Convection's waste classification system will influence the current OECD waste handling system. Some countries adopting the Basel Convention consider end of life electronics to be hazardous waste, whereas the OECD countries consider them to be non hazardous. Also, waste management regulations potentially affecting electronics in Germany and Japan are mentioned in this report.", "author_names": [ "Vasilis M Fthenakis" ], "corpus_id": 167510002, "doc_id": "167510002", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "REGULATIONS ON PHOTOVOLTAIC MODULE DISPOSAL AND RECYCLING.", "venue": "", "year": 2001 }, { "abstract": "Abstract Given the rapid increase in production and installation of PV systems, recycling of PV modules is becoming more and more important. In this paper, three types of recycling pathways from perspectives of close loop life cycle, which are manufacturing waste recycling, disposed module remanufacturing and recycling, are investigated. For each pathway, proven technologies are presented and their advantages and drawbacks are described. The results show that recycling technologies for PV manufacturing wastes and end of life modules are wildly explored and some are commercially available, although the challenges still remain in process efficiency, reduction in process complexity, energy requirements, and use of chemicals. Some research has been conducted on remanufacturing and reuse of PV modules. The ease to disassembly design may improve the reusability of valuable components. It is also found that though studies showed that PV module manufacturing waste recycling and end of life module recycling have significant positive impacts on the reducing environment loads, economic viability of PV module recycling is still unfavorable and policies are needed to encourage producer responsibility not only in the PV manufacturing sector but also in the entire energy industry, and an efficient collection network should be important to the economic viability of PV module recycling business.", "author_names": [ "Jing Tao", "Suiran Yu" ], "corpus_id": 97449192, "doc_id": "97449192", "n_citations": 120, "n_key_citations": 2, "score": 0, "title": "Review on feasible recycling pathways and technologies of solar photovoltaic modules", "venue": "", "year": 2015 }, { "abstract": "The thesis points out practical problems of waste management within the Photovoltaic industry and conclusions are based on empirical data. Benefits for photovoltaic key stakeholders, like module manufacturers, governments and power plant owners are investigated. The conclusions drawn are based on interviews, literature review and online research. So far recycling of crystalline photovoltaic modules is regulated only within the European Union. Current directives governing photovoltaic modules frame the recycling targets in terms of weight. But the loss of resources like aluminium and silver, as well as lead and cadmium leaching have a negative impact on the environment and human health if modules are merely discharged after their life cycle. Eventually these materials will become scarce and affect the future production of photovoltaic modules. Therefore looking at the environmental impact of each raw material is a different, more sustainable approach. Yet, environmental effects are so far not being considered in the stakeholders' decision making. The thesis shows that for manufacturers the main incentives to recycle are profit maximisation and image improvement. Including a recycling strategy into the manufacturing process is therefore actually increases competitiveness within the photovoltaic business. In order to raise awareness for photovoltaic waste, it is suggested to include the photovoltaic modules' decommissioning time into Gantt Charts which might influence photovoltaic owners to purchase modules that are recycled after their life span. A future key development is likely to see recycled materials to be reused for new PV products and substituting materials that are harmful to human health and the environment. An overview of the current technology, legal framework and waste projection for the recycling industry is given in chapter 3 and 4.", "author_names": [ "Agathe Auer" ], "corpus_id": 107353381, "doc_id": "107353381", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "Photovoltaic module decommissioning and recycling in Europe and Japan", "venue": "", "year": 2015 }, { "abstract": "This work deals with methods of recycling of photov ltaic modules and evaluates contribution of recycl ing to the environment and reduction of raw materials extraction. The article d scribes the materials needed to manufacture photo voltaic modules and energy intensity of production processes. Three methods of recycling were used thermal, chemical and mechanical. The experiments have shown that the recycling of PV modules by thermal method is more a dvantageous than using a chemical method. The lengt h of the process is significantly shorter and there are lower financial costs. The di sa vantage of thermal treatment is the formation of emission gases during decomposition of the EVA copolymer and also a risk of wafer damag e. In mechanical recycling process it is very impor tant to know which technologies and devices are suitable to creation of crushed materia l. If the PV modules are bigger than 1 x 1 m, it wa s necessary to divide them into two parts because the chain crusher must be able to crush the piec s as effectively as possible. From the entire mechanical recycling process it can be seen that the silver containing crushed material up to 0.07 is not economically advantageous to proc ess chemically. The silver content does not cover the cost of basic operations during recycling process. The obtained data were used to c alculate the amount of saved material due to PV module recycling until year 2025. Recycli ng could save up to 351 500 tons of glass, 51 500 t ons of aluminium, 13 567 silicon and 425 tons of silver in Czech Republic.", "author_names": [ "David Strachala", "Josef Hylsky", "Gunter Fafilek", "Kristyna Jandova" ], "corpus_id": 46652868, "doc_id": "46652868", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Methods for recycling photovoltaic modules and their impact on environment and raw material extraction", "venue": "", "year": 2017 }, { "abstract": "The installations of photovoltaic (PV) solar modules are growing extremely fast. As a result of the increase, the volume of modules that reach the end of their life will grow at the same rate in the near future. It is expected that by 2050 that figure will increase to 5.5 6 million tons. Consequently, methods for recycling solar modules are being developed worldwide to reduce the environmental impact of PV waste and to recover some of the value from old modules. Current recycling methods can recover just a portion of the materials, so there is plenty of room for progress in this area. Currently, Europe is the only jurisdiction that has a strong and clear regulatory framework to support the PV recycling process. This review presents a summary of possible PV recycling processes for solar modules, including c Si and thin film technologies as well as an overview of the global legislation. So far, recycling processes of c Si modules are unprofitable but are likely to be mandated in more jurisdictions. There is potential to develop new pathways for PV waste management industry development and offer employment and prospects for both public and private sector investors.", "author_names": [ "Marina Lunardi", "Juan Pablo Alvarez-Gaitan", "Jose I Bilbao", "Richard Corkish" ], "corpus_id": 73522732, "doc_id": "73522732", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "A Review of Recycling Processes for Photovoltaic Modules", "venue": "", "year": 2018 }, { "abstract": "Abstract In comparison to other energy producing techniques, photovoltaics (PV) is one of the most promising options: no emission of any matter into the environment during operation; extremely long operation period (estimated average: 25 years) minimum maintenance, robust technique, aesthetic aspects. The use of photovoltaics is rapidly increasing, and the respective market is developing accordingly. Although PV manufacturing equipment is now excluded from the scope of RoHS, according to the Kyoto Protocol and the EU Directives WEEE and RoHS the use of hazardous substances in electric/electronic devices has to be reduced stepwise to approximately zero level. Furthermore, a total recycling of nearly all materials involved is aimed. Thus, major attention is directed to avoidance of environmental pollution through combustion or landfill, to regain valuable material, to promote the development and use of renewable energy sources. As the lifetime of PV cells themselves is much longer than that of PV modules and the manufacturing process of cells requires much energy consumption, the reuse of base material of the cells is economically justified. The aim of this work was to develop and evaluate existing methods of PV cells and modules recycling. The article discusses the main outcomes and analyses the significance of recycling in relation to the environmental profile of the production and total life cycle of photovoltaic cells and modules Abstrakt W porownaniu do innych metod produkcji energii, technologia fotowoltaiczna jest jedna z najbardziej obiecujacych opcji: brak emisji z substancji do srodowiska podczas pracy, bardzo dlugi okres eksploatacji (szacowany srednio na 25 lat) minimalna koniecznosc konserwacji, solidna technika, atuty estetyczne. Rynek modulow fotowoltaicznych na swiecie rozwija sie intensywnie, a stale rosnacy udzial modulow fotowoltaicznych (PV) w swiatowej produkcji energii elektrycznej powoduje, iz zwiekszajaca sie ilosc odpadow w postaci zuzytych lub uszkodzonych ogniw i modulow PV spowoduje w najblizszych latach koniecznosc bardziej racjonalnego ich zagospodarowania. Aby moduly fotowoltaiczne pozostaly bez negatywnego wplywu na srodowisko, konieczne jest wprowadzenie dlugofalowej strategii obejmujacej kompletny ,cykl zycia\" wszystkich elementow systemu: od fazy produkcji, poprzez montaz i eksploatacje az do utylizacji. Recykling odpadow produkcyjnych i zuzytych systemow jest istotnym elementem tej strategii. Korzysci srodowiskowe recyklingu sa zwiazane nie tylko z ograniczeniem miejsca na skladowiskach odpadow, ale rowniez z oszczednoscia energii, surowcow i ograniczeniem emisji. Celem pracy bylo przedstawienie i ocena istniejacych metod recyklingu ogniw i modulow fotowoltaicznych oraz wplywu tego procesu na srodowisko naturalne", "author_names": [ "Ewa Klugmann-Radziemska" ], "corpus_id": 55504291, "doc_id": "55504291", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Current Trends in Recycling of Photovoltaic Solar Cells and Modules Waste Recykling Zuzytych Ogniw I Modulow Fotowoltaicznych Stan Obecny", "venue": "", "year": 2012 }, { "abstract": "Solar photovoltaic (PV) deployment has grown at unprecedented rates since the early 2000s. As the global PV market increases, so will the volume of decommissioned PV panels, and large amounts of annual waste are anticipated by the early 2030s. Growing PV panel waste presents a new environmental challenge, but also unprecedented opportunities to create value and pursue new economic avenues. This report, prepared jointly by the International Renewable Energy Agency (IRENA) and the International Energy Agency Photovoltaic Power Systems Programme (IEA PVPS) is the first ever projection of PV panel waste volumes to 2050. It highlights that recycling or repurposing solar PV panels at the end of their roughly 30 year lifetime can unlock an estimated stock of 78 million tonnes of raw materials and other valuable components globally by 2050. If fully injected back into the economy, the value of the recovered material could exceed USD 15 billion by 2050. Sectors like PV recycling will be essential in the world's transition to a sustainable, economically viable and increasingly renewables based energy future. To unlock the benefits of such PV end of life industries, the institutional groundwork must be laid in time to meet the expected surge in panel waste. Policy action is needed to addressmore the challenges ahead, with enabling frameworks being adapted to the needs and circumstances of each region or country. less", "author_names": [ "Stephanie Weckend", "Andreas Wade", "Garvin A Heath" ], "corpus_id": 114765533, "doc_id": "114765533", "n_citations": 160, "n_key_citations": 11, "score": 0, "title": "End of Life Management: Solar Photovoltaic Panels", "venue": "", "year": 2016 }, { "abstract": "Current global commitments to tackle climate change and reduce greenhouse gas emissions are resulting in increasing demand for wind energy technologies as a secure, affordable supply of energy. However, the recent expansion of wind energy generation is creating a growing waste disposal issue associated with the decommissioning of wind turbine (WT) blades in the future.", "author_names": [ "Ruth Cherrington", "Vannessa Goodship", "James Meredith", "Benjamin M Wood", "Stuart R Coles", "Andre Vuillaume", "A Feito-Boirac", "F Spee", "Kerry Kirwan" ], "corpus_id": 153518711, "doc_id": "153518711", "n_citations": 69, "n_key_citations": 6, "score": 0, "title": "Producer responsibility: Defining the incentive for recycling composite wind turbine blades in Europe", "venue": "", "year": 2012 } ]

[ { "abstract": "The number of emerging applications based on millimeter wave radar sensors is continuously increasing. Several consumer applications offer potential of achieving mass volume production. These can be for example motion detectors for lighting control and door openers, gesture sensing in smart phones, MIMO sensors for traffic monitoring or presence detection in railway stations. Driven by the demand for module size reduction, the operating frequencies of the radar modules keep on increasing, as one can integrate antennas in package and reduce the chip size. Furthermore, driven by the demand for cost reduction, the level of integration of the System on Chip (SoC) is always increasing. The amount of external components shall be reduced by integrating more and more analog, digital, power management and RF functional blocks on the same chip, on a smallest chip area and at a lowest price. Advanced silicon based semiconductor technologies enable such integration, and provide excellent characteristics at mm wave frequencies. However, in view of these trends, one need to evaluate what is the right technology for a particular mm waver radar application in terms of RF performance and costs. The right choice of the technology is not necessarily straightforward, as it often depends on the expected product volume and the development of mask costs and wafer costs.", "author_names": [ "Vadim Issakov" ], "corpus_id": 53017749, "doc_id": "53017749", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Circuit Design Challenges of Highly Integrated mm Wave Radar Based Sensors in SOI Based Technologies", "venue": "ESSCIRC 2018 IEEE 44th European Solid State Circuits Conference (ESSCIRC)", "year": 2018 }, { "abstract": "The number of emerging applications based on millimeter wave radar sensors is continuously increasing. Several consumer applications offer potential of achieving mass volume production. These can be for example motion detectors for lighting control and door openers, gesture sensing in smart phones, MIMO sensors for traffic monitoring or presence detection in railway stations. Driven by the demand for module size reduction, the operating frequencies of the radar modules keep on increasing, as one can integrate antennas in package and reduce the chip size. Furthermore, driven by the demand for cost reduction, the level of integration of the System on Chip (SoC) is always increasing. The amount of external components shall be reduced by integrating more and more analog, digital, power management and RF functional blocks on the same chip, on a smallest chip area and at a lowest price. Advanced silicon based semiconductor technologies enable such integration, and provide excellent characteristics at mm wave frequencies. However, in view of these trends, one need to evaluate what is the right technology for a particular mm waver radar application in terms of RF performance and costs. The right choice of the technology is not necessarily straightforward, as it often depends on the expected product volume and the development of mask costs and wafer costs.", "author_names": [ "Vadim Issakov" ], "corpus_id": 52966958, "doc_id": "52966958", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Circuit Design Challenges of Highly Integrated mm Wave Radar Based Sensors in SOI based Technologies", "venue": "2018 48th European Solid State Device Research Conference (ESSDERC)", "year": 2018 }, { "abstract": "Thank you for downloading design of analog cmos integrated circuits. Maybe you have knowledge that, people have look hundreds times for their chosen books like this design of analog cmos integrated circuits, but end up in malicious downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they juggled with some harmful virus inside their computer. design of analog cmos integrated circuits is available in our book collection an online access to it is set as public so you can download it instantly. Our digital library spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the design of analog cmos integrated circuits is universally compatible with any devices to read.", "author_names": [ "Franziska Hoffmann" ], "corpus_id": 64151023, "doc_id": "64151023", "n_citations": 1204, "n_key_citations": 133, "score": 0, "title": "Design Of Analog Cmos Integrated Circuits", "venue": "", "year": 2016 }, { "abstract": "The future of integrated electronics is the future of electronics itself. The advantages of integration will bring about a proliferation of electronics, pushing this science into many new areas. Integrated circuits will lead to such wonders as home computers or at least terminals connected to a central computer automatic controls for automobiles, and personal portable communications equipment. The electronic wristwatch needs only a display to be feasible today. But the biggest potential lies in the production of large systems. In telephone communications, integrated circuits in digital filters will separate channels on multiplex equipment. Integrated circuits will also switch telephone circuits and perform data processing. Computers will be more powerful, and will be organized in completely different ways. For example, memories built of integrated electronics may be distributed throughout the machine instead of being concentrated in a central unit. In addition, the improved reliability made possible by integrated circuits will allow the construction of larger processing units. Machines similar to those in existence today will be built at lower costs and with faster turnaround.", "author_names": [ "Gordon E Moore" ], "corpus_id": 6519532, "doc_id": "6519532", "n_citations": 10411, "n_key_citations": 444, "score": 0, "title": "Cramming More Components Onto Integrated Circuits", "venue": "Proceedings of the IEEE", "year": 1998 }, { "abstract": "For both introductory and advanced courses in VLSI design, this authoritative, comprehensive textbook is highly accessible to beginners, yet offers unparalleled breadth and depth for more experienced readers. The Fourth Edition of CMOS VLSI Design: A Circuits and Systems perspective presents broad and in depth coverage of the entire field of modern CMOS VLSI Design. The authors draw upon extensive industry and classroom experience to introduce todays most advanced and effective chip design practices. They present extensively updated coverage of every key element of VLSI design, and illuminate the latest design challenges with 65 nm process examples. This book contains unsurpassed circuit level coverage, as well as a rich set of problems and worked examples that provide deep practical insight to readers at all levels.", "author_names": [ "Neil Weste", "D Harris" ], "corpus_id": 108665214, "doc_id": "108665214", "n_citations": 2360, "n_key_citations": 293, "score": 0, "title": "CMOS VLSI Design: A Circuits and Systems Perspective", "venue": "", "year": 2004 }, { "abstract": "An unprecedented transformation in the design, deployment, and application of short range wireless devices and services is in progress today. This trend is in line with the imminent transition from third to fourth generation radio systems, where heterogeneous environments are expected to prevail eventually. A key driver in this transition is the steep growth in both demand and deployment of WLANs/WPANs based on the wireless standards within the IEEE 802 suite. Today, these short range devices and networks operate mainly standalone in indoor home and office environments or large enclosed public areas, while their integration into the wireless wide area infrastructure is still nearly nonexistent and far from trivial. This status quo in the short range wireless application space is about to be disrupted by novel devices and systems based on the emerging UWB radio technology with the potential to provide solutions for many of today's problems in the areas of spectrum management and radio system engineering. The approach employed by UWB radio devices is based on sharing already occupied spectrum resources by means of the overlay principle, rather than looking for still available but possibly unsuitable new bands. This novel radio technology has received legal adoption by the regulatory authorities in the United States, and efforts to achieve this status in Europe and Asia are underway. This article discusses both the application potential and technical challenges presented by UWB radio as an unconventional but promising new wireless technology.", "author_names": [ "Domenico Porcino", "Walter Hirt" ], "corpus_id": 18543046, "doc_id": "18543046", "n_citations": 966, "n_key_citations": 39, "score": 0, "title": "Ultra wideband radio technology: potential and challenges ahead", "venue": "IEEE Commun. Mag.", "year": 2003 }, { "abstract": "This paper describes the design and modeling of CMOS transistors, integrated passives, and circuit blocks at millimeter wave (mm wave) frequencies. The effects of parasitics on the high frequency performance of 130 nm CMOS transistors are investigated, and a peak f/sub max/ of 135 GHz has been achieved with optimal device layout. The inductive quality factor (Q/sub L/ is proposed as a more representative metric for transmission lines, and for a standard CMOS back end process, coplanar waveguide (CPW) lines are determined to possess a higher Q/sub L/ than microstrip lines. Techniques for accurate modeling of active and passive components at mm wave frequencies are presented. The proposed methodology was used to design two wideband mm wave CMOS amplifiers operating at 40 GHz and 60 GHz. The 40 GHz amplifier achieves a peak |S/sub 21/ 19 dB, output P/sub 1dB/ 0.9 dBm, IIP3 7.4 dBm, and consumes 24 mA from a 1.5 V supply. The 60 GHz amplifier achieves a peak |S/sub 21/ 12 dB, output P/sub 1dB/ +2.0 dBm, NF 8.8 dB, and consumes 36 mA from a 1.5 V supply. The amplifiers were fabricated in a standard 130 nm 6 metal layer bulk CMOS process, demonstrating that complex mm wave circuits are possible in today's mainstream CMOS technologies.", "author_names": [ "Chinh H Doan", "Sohrab Emami", "Ali M Niknejad", "Robert W Brodersen" ], "corpus_id": 18647467, "doc_id": "18647467", "n_citations": 713, "n_key_citations": 43, "score": 0, "title": "Millimeter wave CMOS design", "venue": "IEEE Journal of Solid State Circuits", "year": 2005 }, { "abstract": "From the Publisher: Practical and theoretical coverage of RF MEMS for circuits and devices New RF and microwave frequency MEMS (microeletromechanical systems) have potentially enormous and widespread applications in the telecommunications industry. Components based on this technologysuch as switches, varactors, and phase shiftersexhibit virtually no power consumption or loss, making them ideally suited for use in modern telecommunications and wireless devices. This book sets out the basics of RF MEMS and describes how to design practical devices and circuits. As well as covering fundamentals, Gabriel Rebeiz offers expert tips for designers and presents a range of real world applications. Throughout, the author utilizes actual engineering examples to illustrate basic principles in theory and practice. Detailed discussion of cutting edge fabrication and packaging techniques is provided. Suitable as a tutorial for electrical and computer engineering students, or as an up to date reference for practicing circuit designers, RF MEMS provides the most comprehensive available survey of this new and important technology. Author Biography: Gabriel M. Rebeiz received his PhD from the California Institute of Technology, and is Professor of Electrical and Computer Engineering at the University of Michigan, Ann Arbor. In 1991 he was the recipient of the National Science Foundation Presidential Young Investigator Award, and in 2000 was the corecipient of the IEEE Microwave Prize. A Fellow of the IEEE and a consultant to Rockwell, Samsung, Intel, Standard MEMS, and Agilent, he has published extensively in the field of microwave technology and in the area of RF MEMS.", "author_names": [ "Gabriel M Rebeiz" ], "corpus_id": 108034421, "doc_id": "108034421", "n_citations": 1856, "n_key_citations": 154, "score": 0, "title": "RF MEMS: Theory, Design and Technology", "venue": "", "year": 2003 }, { "abstract": "1 An Introduction to Radar 2 The Radar Equation 3 MTI and Pulse Doppler Radar 4 Tracking Radar 5 Detection of Signals in Noise 6 Information from Radar Signals 7 Radar Clutter 8 Propogation of Radar Waves 9 The Radar Antenna 10 Radar Transmitters 11 Radar Receiver", "author_names": [ "Merrill I Skolnik" ], "corpus_id": 129892493, "doc_id": "129892493", "n_citations": 5516, "n_key_citations": 401, "score": 0, "title": "Introduction to Radar Systems", "venue": "", "year": 1979 }, { "abstract": "This tutorial presents an overview of the technological advances in millimeter wave (mm wave) circuit components, antennas, and propagation that will soon allow 60 GHz transceivers to provide multigigabit per second (multi Gb/s) wireless communication data transfers in the consumer marketplace. Our goal is to help engineers understand the convergence of communications, circuits, and antennas, as the emerging world of subterahertz and terahertz wireless communications will require understanding at the intersections of these areas. This paper covers trends and recent accomplishments in a wide range of circuits and systems topics that must be understood to create massively broadband wireless communication systems of the future. In this paper, we present some evolving applications of massively broadband wireless communications, and use tables and graphs to show research progress from the literature on various radio system components, including on chip and in package antennas, radio frequency (RF) power amplifiers (PAs) low noise amplifiers (LNAs) voltage controlled oscillators (VCOs) mixers, and analog to digital converters (ADCs) We focus primarily on silicon based technologies, as these provide the best means of implementing very low cost, highly integrated 60 GHz mm wave circuits. In addition, the paper illuminates characterization techniques that are required to competently design and fabricate mm wave devices in silicon, and illustrates effects of the 60 GHz RF propagation channel for both in building and outdoor use. The paper concludes with an overview of the standardization and commercialization efforts for 60 GHz multi Gb/s devices, and presents a novel way to compare the data rate versus power efficiency for future broadband devices.", "author_names": [ "Theodore Ted S Rappaport", "James Murdock", "Felix Gutierrez" ], "corpus_id": 2722298, "doc_id": "2722298", "n_citations": 773, "n_key_citations": 46, "score": 0, "title": "State of the Art in 60 GHz Integrated Circuits and Systems for Wireless Communications", "venue": "Proceedings of the IEEE", "year": 2011 } ]

[ { "abstract": "We introduce the 2D counterpart of layered black phosphorus, which we call phosphorene, as an unexplored p type semiconducting material. Same as graphene and MoS2, single layer phosphorene is flexible and can be mechanically exfoliated. We find phosphorene to be stable and, unlike graphene, to have an inherent, direct, and appreciable band gap. Our ab initio calculations indicate that the band gap is direct, depends on the number of layers and the in layer strain, and is significantly larger than the bulk value of 0.31 0.36 eV. The observed photoluminescence peak of single layer phosphorene in the visible optical range confirms that the band gap is larger than that of the bulk system. Our transport studies indicate a hole mobility that reflects the structural anisotropy of phosphorene and complements n type MoS2. At room temperature, our few layer phosphorene field effect transistors with 1.0 mm channel length display a high on current of 194 mA/mm, a high hole field effect mobility of 286 cm(2)/V*s, and an on/off ratio of up to 10(4) We demonstrate the possibility of phosphorene integration by constructing a 2D CMOS inverter consisting of phosphorene PMOS and MoS2 NMOS transistors.", "author_names": [ "Han Liu", "Adam T Neal", "Zhen Zhu", "Zhe Luo", "Xianfan Xu", "David Tomanek", "Peide D Ye" ], "corpus_id": 8061668, "doc_id": "8061668", "n_citations": 2990, "n_key_citations": 28, "score": 0, "title": "Phosphorene: an unexplored 2D semiconductor with a high hole mobility.", "venue": "ACS nano", "year": 2014 }, { "abstract": "Phosphorene is a mono elemental, two dimensional (2D) substance with outstanding, highly directional properties and a bandgap that depends on the number of layers of the material1 8. Nanoribbons, meanwhile, combine the flexibility and unidirectional properties of one dimensional nanomaterials, the high surface area of 2D nanomaterials and the electron confinement and edge effects of both. The structures of nanoribbons can thus lead to exceptional control over electronic band structure, the emergence of novel phenomena and unique architectures for applications5,6,9 24. Phosphorene's intrinsically anisotropic structure has motivated numerous theoretical calculations of phosphorene nanoribbons (PNRs) predicting extraordinary properties5,6,12 24. So far, however, discrete PNRs have not been produced. Here we present a method for creating quantities of high quality, individual PNRs by ionic scissoring of macroscopic black phosphorus crystals. This top down process results in stable liquid dispersions of PNRs with typical widths of 4 50 nm, predominantly single layer thickness, measured lengths of up to 75 mm and aspect ratios of up to 1,000. The nanoribbons are atomically flat single crystals, aligned exclusively in the zigzag crystallographic orientation. The ribbons have remarkably uniform widths along their entire lengths, and are extremely flexible. These properties together with the ease of downstream manipulation via liquid phase methods should enable the search for predicted exotic states6,12 14,17 19,21, and an array of applications in which PNRs have been predicted to offer transformative advantages. These applications range from thermoelectric devices to high capacity fast charging batteries and integrated high speed electronic circuits6,14 16,20,23,24.Phosphorene nanoribbons are produced in liquids through the intercalation of black phosphorous crystals with lithium ions, enabling the search for predicted exotic states and applications of these nanoribbons.", "author_names": [ "Mitchell C Watts", "Lorenzo Picco", "F S Russell-Pavier", "Patrick L Cullen", "Thomas S Miller", "Szymon Bartus", "Oliver D Payton", "Neal T Skipper", "Vasiliki Tileli", "Christopher A Howard" ], "corpus_id": 106410439, "doc_id": "106410439", "n_citations": 98, "n_key_citations": 1, "score": 1, "title": "Production of phosphorene nanoribbons", "venue": "Nature", "year": 2019 }, { "abstract": "A fundamental understanding of the phonon transport mechanism is important for optimizing the efficiency of thermoelectric devices. In this study, we investigate the thermal transport properties of the oxidized form of phosphorene called phosphorene oxide (PO) by solving phonon Boltzmann transport equation based on first principles density functional theory. We reveal that PO exhibits a much lower thermal conductivity (2.42 7.08 W/mK at 300 K) than its pristine counterpart as well as other two dimensional materials. To comprehend the physical origin of such low thermal conductivity, we scrutinize the contribution of each phonon branch to the thermal conductivity by evaluating various mode dependent quantities including Gruneisen parameters, anharmonic three phonon scattering rate, and phase space of three phonon scattering processes. Our results show that its flexible puckered structure of PO leads to smaller sound velocities; its broken mirror symmetry allows more ZA phonon scattering; and the relatively free vibration of dangling oxygen atoms in PO gives rise to additional scattering resulting in further reduction in the phonon lifetime. These results can be verified by the fact that PO has larger phase space for three phonon processes than phosphorene. Furthermore we show that the thermal conductivity of PO can be optimized by controlling its size or its phonon mean free path, indicating that PO can be a promising candidate for low dimensional thermoelectric devices.", "author_names": [ "Seungjun Lee", "Seoung-Hun Kang", "Young-Kyun Kwon" ], "corpus_id": 53663700, "doc_id": "53663700", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Low Lattice Thermal Conductivity of a Two Dimensional Phosphorene Oxide", "venue": "Scientific Reports", "year": 2019 }, { "abstract": "The generation of green hydrogen (H2 energy using sunlight is of great significance to solve the worldwide energy and environmental issues. Particularly, photocatalytic H2 production is a highly promising strategy for solar to H2 conversion. Recently, various heterostructured photocatalysts with high efficiency and good stability have been fabricated. Among them, 2D/2D van der Waals (VDW) heterojunctions have received tremendous attention, since this architecture can promote the interfacial charge separation and transfer and provide massive reactive centers. On the other hand, currently, most photocatalysts are composed of metal elements with high cost, limited reserves, and hazardous environmental impact. Hence, the development of metal free photocatalysts is desirable. Here, a novel 2D/2D VDW heterostructure of metal free phosphorene/graphitic carbon nitride (g C3 N4 is fabricated. The phosphorene/g C3 N4 nanocomposite shows an enhanced visible light photocatalytic H2 production activity of 571 umol h 1 g 1 in 18 v% lactic acid aqueous solution. This improved performance arises from the intimate electronic coupling at the 2D/2D interface, corroborated by the advanced characterizations techniques, e.g. synchrotron based X ray absorption near edge structure, and theoretical calculations. This work not only reports a new metal free phosphorene/g C3 N4 photocatalyst but also sheds lights on the design and fabrication of 2D/2D VDW heterojunction for applications in catalysis, electronics, and optoelectronics.", "author_names": [ "Jingrun Ran", "Weiwei Guo", "Hailong Wang", "Bicheng Zhu", "Jiaguo Yu", "Shizhang Qiao" ], "corpus_id": 14060255, "doc_id": "14060255", "n_citations": 411, "n_key_citations": 1, "score": 0, "title": "Metal Free 2D/2D Phosphorene/g C3 N4 Van der Waals Heterojunction for Highly Enhanced Visible Light Photocatalytic H2 Production.", "venue": "Advanced materials", "year": 2018 }, { "abstract": "As the development of oxygen evolution co catalysts (OECs) is being actively undertaken, the tailored integration of those OECs with photoanodes is expected to be a plausible avenue for achieving highly efficient solar assisted water splitting. Here, we demonstrate that a black phosphorene (BP) layer, inserted between the OEC and BiVO4 can improve the photoelectrochemical performance of pre optimized OEC/BiVO4 (OEC: NiOOH, MnOx, and CoOOH) systems by 1.2~1.6 fold, while the OEC overlayer, in turn, can suppress BP self oxidation to achieve a high durability. A photocurrent density of 4.48 mA*cm 2 at 1.23 V vs reversible hydrogen electrode (RHE) is achieved by the NiOOH/BP/BiVO4 photoanode. It is found that the intrinsic p type BP can boost hole extraction from BiVO4 and prolong holes trapping lifetime on BiVO4 surface. This work sheds light on the design of BP based devices for application in solar to fuel conversion, and also suggests a promising nexus between semiconductor and electrocatalyst.Photoelectrochemical water splitting affords an integrated approach for converting light to fuel, but devices typically suffer poor activities and stabilities. Here, authors incorporate black phosphorene into bismuth vanadate photoanodes to boost hole extraction and device lifetimes.", "author_names": [ "Kan Zhang", "Bingjun Jin", "Cheolwoo Park", "Yoonjun Cho", "Xiufeng Song", "Xinjian Shi", "Shengli Zhang", "Wooyul Kim", "Haibo Zeng", "Jong Hyeok Park" ], "corpus_id": 141509258, "doc_id": "141509258", "n_citations": 83, "n_key_citations": 0, "score": 0, "title": "Black phosphorene as a hole extraction layer boosting solar water splitting of oxygen evolution catalysts", "venue": "Nature Communications", "year": 2019 }, { "abstract": "Phosphorene, also known as single or few layer black phosphorus (FLBP) is a new member of the two dimensional (2D) material family and has attracted significant attention in recent years for applications in optoelectronics, energy storage and biomedicine due to its unique physicochemical properties and excellent biocompatibility. FLBP is regarded as a potential biological imaging agent for cancer diagnosis due to its intrinsic fluorescence (FL) and photoacoustic (PA) properties and negligible cytotoxicity. FLBP based photothermal and photodynamic therapies have emerged with excellent anti tumour therapeutic efficacies due to their unique physical properties, such as near infrared (NIR) optical absorbance, large extinction coefficients, biodegradability and reactive oxygen species (ROS) or heat generation upon light irradiation. Furthermore, FLBP is a promising drug delivery platform because of its high drug loading capacity due to its puckered layer structure with an ultralarge surface area, and FLBP is size controllable with facile surface chemical modification. Because of the marked advantages of FLBP nanomaterials in biomedical applications, an overview of the latest progress and paradigms of FLBP based nanoplatforms for multidisciplinary biomedical applications is presented in this tutorial review.", "author_names": [ "Meng Qiu", "Wen Xiu Ren", "Tae-Hyeon Jeong", "Miae Won", "Geun Young Park", "David Kipkemoi Sang", "Li-ping Liu", "Han Zhang", "Jong Seung Kim" ], "corpus_id": 46956907, "doc_id": "46956907", "n_citations": 209, "n_key_citations": 0, "score": 0, "title": "Omnipotent phosphorene: a next generation, two dimensional nanoplatform for multidisciplinary biomedical applications.", "venue": "Chemical Society reviews", "year": 2018 }, { "abstract": "Two dimensional materials have allowed for great advances in the biosensors field and to obtain sophisticated, smart, and miniaturized devices. In this work, we optimized a highly sensitive and selective phenol biosensor using 2D pnictogens (phosphorene, arsenene, antimonene, and bismuthene) as sensing platforms. Exfoliated pnictogen were obtained by the shear force method, undergoing delamination and downsizing to thin nanosheets. Interestingly, compared with the other tested elements, antimonene exhibited the highest degree of exfoliation and the lowest oxidation to bulk ratio, to which we attribute its enhanced performance in the phenol biosensor system reported here. The proposed design represents the first biosensor approach developed using exfoliated pnictogens beyond phosphorene.", "author_names": [ "Carmen C Mayorga-Martinez", "Rui Gusmao", "Zdenek Sofer", "Martin Pumera" ], "corpus_id": 53291371, "doc_id": "53291371", "n_citations": 59, "n_key_citations": 0, "score": 0, "title": "Pnictogen Based Enzymatic Phenol Biosensors: Phosphorene, Arsenene, Antimonene, and Bismuthene.", "venue": "Angewandte Chemie", "year": 2019 }, { "abstract": "Abstract We report on a first principles study of the electronic and transport properties of pristine, B C N O doped blue phosphorene (BlueP) with the adsorption of gas molecules NH3, NO, NO2, CO, and CO2. The adsorption distances, adsorption energies, charge transfer, density of states (DOS) and transmission spectra of these gas molecules on molecules on doped as well as undoped BlueP is systematically investigated in this work. Our calculations show that the adsorption energy of NO and NO2 on pristine BlueP is the largest among the considered gas molecules, suggesting that pristine BlueP is more sensitive to these two gases. The results indicate that the pristine BlueP exhibits a weak sensitivity to NH3 and CO molecules, while B doped BlueP strongly adsorbs NH3 and CO by way of strong chemical bonds. C doped BlueP can enhance the sensitivity to NH3 gas molecules. The current voltage (I V) characteristics of the sensors are calculated using non equilibrium the Green's function (NEGF) formalism. Theses sensors show characteristic responses along both the zigzag and the armchair directions depending on the type of the gas molecules.", "author_names": [ "Fatemeh Safari", "Mahdi Moradinasab", "Morteza Fathipour", "Hans Kosina" ], "corpus_id": 104556673, "doc_id": "104556673", "n_citations": 54, "n_key_citations": 0, "score": 0, "title": "Adsorption of the NH3, NO, NO2, CO2, and CO gas molecules on blue phosphorene: A first principles study", "venue": "", "year": 2019 }, { "abstract": "Abstract Non Equilibrium Green's function (NEGF) and density functional theory (DFT) method is employed in exploring the geometric, electronic and adsorption aspects of phosgene (COCl2) on phosphorene nanosheet based molecular device. Further, the attributes such as Bader charge transfer, energy band gap, and average energy gap variation assists in scrutinizing the surface assimilating properties of COCl2 gas on phosphorene nanosheet. Besides, the detection properties of COCl2 gas molecules using the phosphorene nanosheet device are evidenced by the transmission spectrum and V I characteristics. Thus, the current work establishes the foundation for employing phosphorene nanosheet based molecular device in sensing COCl2 gas molecules.", "author_names": [ "R Bhuvaneswari", "Ramanathan Chandiramouli" ], "corpus_id": 104316432, "doc_id": "104316432", "n_citations": 41, "n_key_citations": 0, "score": 0, "title": "First principles investigation on detection of phosgene gas molecules using phosphorene nanosheet device", "venue": "Chemical Physics Letters", "year": 2019 }, { "abstract": "Abstract Based on spin polarized DFT calculations, we have studied the interaction mechanism of recently synthesized blue phosphorene (BlueP) monolayers towards selected key volatile organic compounds (VOCs) such as acetone, ethanol and propanal. Our binding energy analysis shows that pristine BlueP weakly binds the VOCs and that this binding does not appreciably change the electronic properties of the monolayer a prerequisite for any sensing material. However, mono, di, and tri vacancy defects and Si/S substitutional doping significantly enhance the binding energies with VOCs. Density of state (DOS) calculations show that upon adsorption of VOCs, mono vacancy and S substituted BlueP monolayers undergo a major change in electronic structure, which make them potential candidates for VOCs sensing materials. By contrast, binding of VOCs to di and tri vacancy and Si substitution sites does not alter the electronic structure of BlueP monolayers drastically, therefore, are not qualified for VOCs sensing applications.", "author_names": [ "Suyang Sun", "Tanveer Hussain", "Wei Zhang", "Amir Karton" ], "corpus_id": 155501765, "doc_id": "155501765", "n_citations": 47, "n_key_citations": 0, "score": 0, "title": "Blue phosphorene monolayers as potential nano sensors for volatile organic compounds under point defects", "venue": "Applied Surface Science", "year": 2019 } ]

[ { "abstract": "Preface. About the Authors. Acknowledgments. 1 Power Amplifier Fundamentals. 1.1 Introduction. 1.2 Definition of Power Amplifier Parameters. 1.3 Distortion Parameters. 1.4 Power Match Condition. 1.5 Class of Operation. 1.6 Overview of Semiconductors for PAs. 1.7 Devices for PA. 1.8 Appendix: Demonstration of Useful Relationships. 1.9 References. 2 Power Amplifier Design. 2.1 Introduction. 2.2 Design Flow. 2.3 Simplified Approaches. 2.4 The Tuned Load Amplifier. 2.5 Sample Design of a Tuned Load PA. 2.6 References. 3 Nonlinear Analysis for Power Amplifiers. 3.1 Introduction. 3.2 Linear vs. Nonlinear Circuits. 3.3 Time Domain Integration. 3.4 Example. 3.5 Solution by Series Expansion. 3.6 The Volterra Series. 3.7 The Fourier Series. 3.8 The Harmonic Balance. 3.9 Envelope Analysis. 3.10 Spectral Balance. 3.11 Large Signal Stability Issue. 3.12 References. 4 Load Pull. 4.1 Introduction. 4.2 Passive Source/Load Pull Measurement Systems. 4.3 Active Source/Load Pull Measurement Systems. 4.4 Measurement Test sets. 4.5 Advanced Load Pull Measurements. 4.6 Source/Load Pull Characterization. 4.7 Determination of Optimum Load Condition. 4.8 Appendix: Construction of Simplified Load Pull Contours through Linear Simulations. 4.9 References. 5 High Efficiency PA Design Theory. 5.1 Introduction. 5.2 Power Balance in a PA. 5.3 Ideal Approaches. 5.4 High Frequency Harmonic Tuning Approaches. 5.5 High Frequency Third Harmonic Tuned (Class F) 5.6 High Frequency Second Harmonic Tuned. 5.7 High Frequency Second and Third Harmonic Tuned. 5.8 Design by Harmonic Tuning. 5.9 Final Remarks. 5.10 References. 6 Switched Amplifiers. 6.1 Introduction. 6.2 The Ideal Class E Amplifier. 6.3 Class E Behavioural Analysis. 6.4 Low Frequency Class E Amplifier Design. 6.5 Class E Amplifier Design with 50# Duty cycle. 6.6 Examples of High Frequency Class E Amplifiers. 6.7 Class E vs. Harmonic Tuned. 6.8 Class E Final Remarks. 6.9 Appendix: Demonstration of Useful Relationships. 6.10 References. 7 High Frequency Class F Power Amplifiers. 7.1 Introduction. 7.2 Class F Description Based on Voltage Wave shaping. 7.3 High Frequency Class F Amplifiers. 7.4 Bias Level Selection. 7.5 Class F Output Matching Network Design. 7.6 Class F Design Examples. 7.7 References. 8 High Frequency Harmonic Tuned Power Amplifiers. 8.1 Introduction. 8.2 Theory of Harmonic Tuned PA Design. 8.3 Input Device Nonlinear Phenomena: Theoretical Analysis. 8.4 Input Device Nonlinear Phenomena: Experimental Results. 8.5 Output Device Nonlinear Phenomena. 8.6 Design of a Second HT Power Amplifier. 8.7 Design of a Second and Third HT Power Amplifier. 8.8 Example of 2nd HT GaN PA. 8.9 Final Remarks. 8.10 References. 9 High Linearity in Efficient Power Amplifiers. 9.1 Introduction. 9.2 Systems Classification. 9.3 Linearity Issue. 9.4 Bias Point Influence on IMD. 9.5 Harmonic Loading Effects on IMD. 9.6 Appendix: Volterra Analysis Example. 9.7 References. 10 Power Combining. 10.1 Introduction. 10.2 Device Scaling Properties. 10.3 Power Budget. 10.4 Power Combiner Classification. 10.5 The T junction Power Divider. 10.6 Wilkinson Combiner. 10.7 The Quadrature (90 Hybrid. 10.8 The 180 Hybrid (Ring Coupler or Rat race) 10.9 Bus bar Combiner. 10.10 Other Planar Combiners. 10.11 Corporate Combiners. 10.12 Resonating Planar Combiners. 10.13 Graceful Degradation. 10.14 Matching Properties of Combined PAs. 10.15 Unbalance Issue in Hybrid Combiners. 10.16 Appendix: Basic Properties of Three port Networks. 10.17 References. 11 The Doherty Power Amplifier. 11.1 Introduction. 11.2 Doherty's Idea. 11.3 The Classical Doherty Configuration. 11.4 The 'AB C' Doherty Amplifier Analysis. 11.5 Power Splitter Sizing. 11.6 Evaluation of the Gain in a Doherty Amplifier. 11.7 Design Example. 11.8 Advanced Solutions. 11.9 References. Index.", "author_names": [ "Paolo Colantonio", "Franco Giannini", "Ernesto Limiti" ], "corpus_id": 109853195, "doc_id": "109853195", "n_citations": 275, "n_key_citations": 21, "score": 1, "title": "High Efficiency RF and Microwave Solid State Power Amplifiers", "venue": "", "year": 2009 }, { "abstract": "In the last 10 years or so wide bandgap transistors (SiC MESFETs and GaN HEMTs) have appeared on the market for high power RF/microwave transistors. They offer higher power density and higher voltage operation, which in turn are associated with much lower parasitic capacitances and much higher load line dynamic resistance, and hence wider bandwidth applications. Of the two kinds the GaN HEMTs offer higher gain performance and became dominant on the market. The much wider bandwidth matching networks though could not be designed optimally with the traditional Smith Chart and optimization techniques [1] The new requirements for broadband high power and high efficiency performance requires new more sophisticated matching networks synthesis techniques such as the real frequency technique [4] [7]", "author_names": [ "Ivan Boshnakov", "Anna Wood", "Simon Taylor" ], "corpus_id": 110797161, "doc_id": "110797161", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "RF and microwave solid state power amplifiers design requires specialised engineering", "venue": "", "year": 2012 }, { "abstract": "Two solid state power amplifiers with record high power added efficiency (PAE) and 100 130 mW output power in 250 nm InP HBT are reported. The 71 95 GHz PA demonstrates 20.7 dB S21 and 25 GHz 3 dB bandwidth at 432.5 mW PDC. Pout is 105 138 mW (21 36% PAE) and RF power density is 1.64 2.15 W/mm. At 81 GHz, 135.6 mW Pout is achieved with 36.0% PAE and 14.1 dB gain. At 81 GHz with reduced input stage bias, 129.6 mW Pout is achieved with 40.0% PAE and 13.0 dB gain. The 96 120 GHz PA demonstrates 17.8 dB S21 and 26 GHz 3 dB bandwidth at 442.4 mW PDC. Pout is 84.9 107 mW and RF power density is 1.33 1.64 W/mm. At 102.5 GHz, 98.1 mW Pout is achieved with 21.2% PAE and 12.1 dB gain. The results were obtained class A DC biasing the PA's. The amplifiers utilizes a novel, compact, and stackable power cell topology for multi finger HBTs operating at mm wave and THz frequencies, where 8 way PA cell combining can be realized for future 0.6 0.8 W Pout designs these designs are currently under development. This work represents record PAE for 100 mW PA's at these frequencies. 40% PAE at E band (81 GHz) is demonstrated for the first time under class A bias, as well as PAE greater than 23% across the 71 76, 81 86, and 92 95 GHz bands. The 18.9 22.5% PAE at 100 mW power for the 96 120 GHz PA is a 1.5 3x improvement to state of the art PAE at these frequencies.", "author_names": [ "Zach Griffith", "Miguel E Urteaga", "Petra Rowell", "Richard Pierson" ], "corpus_id": 23851228, "doc_id": "23851228", "n_citations": 18, "n_key_citations": 1, "score": 0, "title": "71 95 GHz (23 40% PAE) and 96 120 GHz (19 22% PAE) high efficiency 100 130 mW power amplifiers in InP HBT", "venue": "2016 IEEE MTT S International Microwave Symposium (IMS)", "year": 2016 }, { "abstract": "In this paper solid state microwave power amplifiers, which have been developed by GTE Telecomunicazioni for radio link equipments, are described. The main advantages of these \"division multiplication\" amplifier systems are considered, with reference to both the high overall efficiency and output power. Particular attention is paid to the performance improvements obtained by using broadband thin film frequency multipliers and transistorized microwave dividers.", "author_names": [ "A Faotto" ], "corpus_id": 13490161, "doc_id": "13490161", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "RF Power Solid State Amplifiers for Microwave Radio", "venue": "1976 6th European Microwave Conference", "year": 1976 }, { "abstract": "A novel Ka band high efficiency asymmetric waveguide four port combiner for coherent combining of two Monolithic Microwave Integrated Circuit (MMIC) Solid State Power Amplifiers (SSPAs) having unequal outputs has been successfully designed, fabricated and characterized over the NASA deep space frequency band from 31.8 to 32.3 GHz. The measured combiner efficiency is greater than 90 percent, the return loss greater than 18 dB and input port isolation greater than 22 dB. The manufactured combiner was designed for an input power ratio of 2:1 but can be custom designed for any arbitrary power ratio. Applications considered are NASA s space communications systems needing 6 to 10 W of radio frequency (RF) power. This Technical Memorandum (TM) is an expanded version of the article recently published in Institute of Engineering and Technology (IET) Electronics Letters.", "author_names": [ "Edwin G Wintucky", "Rainee N Simons", "Christine T Chevalier", "John Christian Freeman" ], "corpus_id": 107389511, "doc_id": "107389511", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Efficiency Ka Band Solid State Power Amplifier Waveguide Power Combiner", "venue": "", "year": 2010 }, { "abstract": "Energy efficient conversion of electrical grid power into radio frequency power is becoming one of the key aspects of future accelerators. A significant part of the initial investment and running costs of these machines will be determined by the cost and efficiency of their RF systems. For largescale accelerators, which are proposed for instance by the International Linear Collider Study or by the Future Circular Collider Study, RF efficiency will likely be a determining factor in the approval process. Efforts are already in place to stretch the efficiency of existing RF sources to higher levels. Well known technologies such as klystrons are being reinvented with modern day beam physics, inductive output tubes are being combined for higher power output, and modular solid state amplifiers are becoming more popular as RF sources for accelerators. This talk will give an overview of recent advances and trends in RF source developments. It will discuss future needs and the strategy towards higher efficiency devices for the benefit of the accelerator community. THE NEED FOR HIGHER EFFICIENCY RF SOURCES The electrical power consumption of future accelerators will be driven to a large part by their RF systems. This is particularly true for electron colliders, circular (e.g. FCC) or linear (e.g. ILC or CLIC) which need RF systems in the order of 100 MW or above (see Table 1, [1 6] Other examples with significant RF power consumption are high power hadron linacs (e.g. ESS) and cyclotrons (PSI) for neutron science or Accelerator Driven Systems. In the case of hadron colliders, magnet systems dominate electrical power consumption while RF systems only use a few percent. At CERN, where most accelerators are circular, only 6% of the annual consumption 1.1 TWh in 2017) are caused by the RF systems. For a 3 TeV CLIC machine, around 50% of the facility power consumption is due to the RF system. With an estimated yearly total of 2.74 TWh [4] and a European average price for non household consumption of 0.1e/kWh in 2017, this translates into 187 Me of electricity costs/year for the RF system alone. Therefore every percentage point in RF efficiency has a significant impact on the running cost. For Accelerator Driven Systems (ADS) the power to run the accelerator complex (including cooling, ventilation, cryogenics, offices, etc. must be small (5 10% compared to the power, which is produced in the ADS core. To achieve these values the accelerator complex must have a total efficiency between 0.2 eacc 0.4 [7] which presents a challenge for today's accelerators. If not achieved, the idea [email protected] Table 1: RF Power for Various Future Accelerators Project Ptotal [MW] PRF [MW] Pbeam [MW] PSI* 10 4 1.3 LEP2+ 120 42 19 FCC ee+ tbd 165 100 ESS* 35 15 5 CLIC 500* 272 109 9.8 ILC 500* 164 68 9.4 CLIC 3000* 582 289 28 total power is for the whole facility with experiments, +without injector of using ADS for energy production is unlikely to become economically viable [8] TODAY'S TECHNOLOGIES NEW DEVELOPMENTS In the following we will review today's state of the art of high power RF sources (see Table 2) and point to developments, which may change their efficiencies or power reach in the near future. As pulsed and Continuous Wave (CW) operation pose different challenges to the RF sources both modes of operation will be treated. Modulator Efficiency Most high power RF sources need a High voltage (HV) modulator, which transforms the voltage of the electrical grid to the HV and pulse pattern needed by the RF source. For CW operation in general but also for pulsed operation of gridded tubes (tetrodes, IOTs) the modulator is basically a HV power supply. Pulsed power for gridded tubes is obtained by simply pulsing the grid using the input RF signal, whereas HV pulses for the operation of non gridded tubes (klystrons, magnetrons) have to be formed by the modulator itself. Various topologies have been developed in recent years, which are adapted to different pulse lengths and voltage needs [9] i) Traditional pulse transformer based modulators with efficiencies between 85% and 90% and rise times in the range of a few hundred microseconds. ii) High frequency transformer based modulators such as the resonant polyphase design employed at SNS [10] or the stacked multi level (SML) design developed and used by the European Spallation Source (ESS) with efficiencies up to 92% and with a very short rise time in the range of 100 ms. iii) Transformerless modulators such as the Marx generator [11] which have the potential for even higher efficiency, or direct switch designs. 9th International Particle Accelerator Conference IPAC2018, Vancouver, BC, Canada JACoW Publishing ISBN: 978 3 95450 184 7 doi:10.18429/JACoW IPAC2018 MOYGB1", "author_names": [ "Frank Gerigk" ], "corpus_id": 116382352, "doc_id": "116382352", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Status and Future Strategy for Advanced High Power Microwave Sources for Accelerators", "venue": "", "year": 2018 }, { "abstract": "NASA is planning a number of Space Exploration, Earth Observation and Space Science missions where Ka band solid state power amplifiers (SSPAs) could have a role. Monolithic microwave integrated circuit (MMIC) based SSPAs with output powers on the order of 10 W at Ka band frequencies would be adequate to satisfy the data transmission rate requirements at the distances involved. MMICs are a type of integrated circuit fabricated on a GaAs wafer, which operates at micro wave frequencies and performs the function of signal amplification. The highest power Ka band (31.8 to 32.3 GHz) SSPA to have flown in space had an output power of 2.6 W with an overall efficiency of 14.3 percent. This SSPA was built around discrete GaAs pHEMT (high electron mobility transistor) devices and flew aboard the Deep Space One spacecraft. State of the art GaAs pHEMT based MMIC power amplifiers (PAs) can deliver RF power at Ka band frequencies anywhere from 3 W with a power added efficiency (PAE) of 32 percent to 6 W with a PAE of 26 percent. However, to achieve power levels higher than 6 W, the output of several MMIC PAs would need to be combined using a high efficiency power combiner. Conventional binary waveguide power combiners, based on short slot and magic T circuits, require MMIC PAs with identical amplitude and phase characteristics for high combining efficiency. However, due to manufacturing process variations, the output powers of the MMIC PAs tend to be unequal, and hence the need to develop unequal power combiners. A two way asymmetric magic T based power combiner for MMIC power amplifiers, which can take in unequal inputs, has been successfully designed, fabricated, and characterized over NASA s Deep Space Network (DSN) frequency range of 31.8 to 32.3 GHz. The figure is a transparent view of the a sym metric combiner that shows the 4 port configuration and the internal structure. The rod, post, and iris are positioned by design to achieve the desired asymmetric power ratio, phase equality, and port isolation. Although the combiner was designed for an input power ratio of 2:1, it can be custom designed for any arbitrary power ratio and frequency range. The manufactured prototype combiner was precision machined from aluminum and is less than 2 in.3 (32.8 cm3) Previously investigated rectangular waveguide unequal power combiners were based on shunt/series coupling slots, E plane septums, or H plane T junctions. All the prior art unequal power combiners operated at or below X band (10 GHz) frequencies and were primarily used in the feed network of antenna arrays. The only reported asymmetric magic T was developed as a 2:1 power divider for operation at a much lower frequency, around 500 MHz. The measured power ratio when tested as a power divider was very close to 2 and the phase balance was within 2.6, resulting in near ideal performance. When tested as a combiner using two MMIC SSPAs with a 2:1 power output ratio, an efficiency greater than 90 percent was demonstrated over the 500 MHz DSN frequency range. The return loss at the combiner output port (1) was greater than 18 dB and the input port (2 and 3) isolation was greater than 22 dB. The results show the asymmetric combiner to be a good candidate for high efficiency power combining of two or more SSPAs needed to achieve the 6 to 10 W required by space communications systems of future NASA missions.", "author_names": [ "Edwin G Wintucky", "Rainee N Simons", "John Christian Freeman", "Christine T Chevalier" ], "corpus_id": 106962863, "doc_id": "106962863", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "High Efficiency Ka Band Waveguide Two Way Asymmetric Power Combiner", "venue": "", "year": 2011 }, { "abstract": "The two basic types of RF power amplifiers are TWT amplifiers (TWTAs) and solid state power amplifiers (SSPAs) At the lower frequency bands, for example UHF (300 MHz to 3 GHz) SSPAs predominate while TWTAs are typically used at higher microwave frequencies. As discussed in Chapter 1, the basic building block of an SSPA is a power transistor. A single transistor can act as an amplifier, but to meet a certain gain or power output requirement, several stages containing one or more transistors are usually cascaded together. For example, Figure 3.1 shows a three stage power amplifier; the first or input stage has high gain and low output power since the signal level is low, while the final or output stage typically has low gain but high output power. Output stages often use two or more devices in parallel to increase the available output power. The purpose of the second or driver stage is to provide sufficient input power to the output stage; if the driver is not powerful enough, then the potential high power output will never actually be achieved. Chapter 5 shows several practical examples of different amplifier line ups. One of the many important parameters of an amplifier is its power conversion efficiency (symbol e, units Power conversion efficiency is a measure of how effectively an amplifier converts power drawn from the dc supply to useful signal (RF) power delivered to a load, that is, 79", "author_names": [], "corpus_id": 18266308, "doc_id": "18266308", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Power Amplifiers and System Design 3.1 Amplifier Efficiency", "venue": "", "year": null }, { "abstract": "Power amplification at microwave frequency and above is one of strategic targets under investigation of vacuum microelectronic devices, because it has possibilities to generate more output power and higher frequency than solid state devices. Most of this work has focussed on a triode structure commonly based on a field emission array (FEA)l) FEA is sufficiently nonlinear in I V characteristics associated with Fowler Nordheim equation, which provides highly efficient operation, as expected from B and C class amplifiers. This is an additional advantage in EA based devices. FEA driven by RF power emits a pulsed electron beam with narrow width repeated at the RF signal. When the beam is sufficiently accelerated and coupled with a RF circuit, one can create a high power and high efficiency amplifier having a simple structure without the velocity modulation required in a multicavity klystron. Additionally, highly efficient harmonic amplification up to a higher order becomes possible by coupling with a harmonic RF circuit2) The paper describes the expected operation for the tubes. Figure 1 shows a schematic drawing of the microwave amplifier or frequency multiplier using the FEA. Figure 2 shows a phase distribution of emitted electron current density calculated for a RF FEA with tip density of 1.6x107A/cm2 by using the WKB approximation under a suitable tip shape. The emitted electrons are well bunched within a narrow range of RF phase, as shown in Fig. 2. Table 1 shows the peak efficiencies and output powers for the fundamental and higher harmonic operations. Here, the cathode diameter of lmm and an accelerating voltage of 30kV are assumed. Extraordinarily high efficiencies of 97% 90% 78% and 50% are expected at the fundamental, second, third and even fifth harmonics, respectively, and several tenth kW of output power are extracted from the simple and light weight tube. Operation frequency is commonly limited by the cut off frequency governed by transconductance and the parasitic capacitance of the FEA. However, there are many method to overcome the frequency limitation. For examples, since FEA is installed in a reentrant cavity at high frequency operation, a field emission may be extracted by RF field added on DC bias or basically no extraction electrode may be required for RF FEA operation. Furthermore, distributed interaction structure and Bragg resonator structure with or without gate electrode may be considered at millimeter waves and optical waves3)", "author_names": [ "Kuniyoshi Yokoo", "Hidetaka Shimawaki", "Shoichi Ono" ], "corpus_id": 108596906, "doc_id": "108596906", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Proposal Of A High Efficiency Microwave Power Source Using A Field Emission Array", "venue": "[Proceedings] IVMC '93 Sixth International Vacuum Microelectronics Conference", "year": 1993 }, { "abstract": "Modern communication satellites carrying large numbers of signals require High PoWer Amplifiers (HPAs) which provide RF power with high linearity and high efficiency. Solid state power amplifiers (SSPAs) and travelling wave tube amplifiers (TWTAs) are the candidates for thiS application. Predistortidn linearizer circuits, are used to improve the performance of these aimplifier types. A 10.7 to 12.75 GHz predistortion linearizer is realized in coplanar waveguide tchnology with only three active elements, two Schottky diodes and one monolilthic microwave integrated circuit (MMIC) amplifier. This linearizer shows good capabilities for gain and phase adjustments: gain expansion of 5 dB and phase shift between 20 and 50 degrees can be obtained with this circuit over 2 GHz of bandwidth and about 10 12 dB input power dynamic range. Furtheron, the linearizer offers an input and output VSWR of better 1.4 1 over bandwidth. Low mass and size and increased reliability makes this linearizer suitable for satellite as well as for ground station applications.", "author_names": [ "Gerhard Eggers", "Rudolf Kohl" ], "corpus_id": 25647362, "doc_id": "25647362", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "2 GHz Bandwidth Predistortion Linearizer for Microwave Power Amplifiers at Ku Band", "venue": "1994 24th European Microwave Conference", "year": 1994 } ]

[ { "abstract": "Preface. About the Author. List of Symbols. 1 Introduction. 1.1 Classification of Power Supplies. 1.2 Basic Functions of Voltage Regulators. 1.3 Power Relationships in DC DC Converters. 1.4 DC Transfer Functions of DC DC Converters. 1.5 Static Characteristics of DC Voltage Regulators. 1.6 Dynamic Characteristics of DC Voltage Regulators. 1.7 Linear Voltage Regulators. 1.8 Topologies of PWM DC DC Converters 1.9 Relationships among Current, Voltage, Energy, and Power. 1.10 Electromagnetic Compatibility. 1.11 Summary. 1.12 References. 1.13 Review Questions. 1.14 Problems. 2 BuckPWMDC DCConverter. 2.1 Introduction. 2.2 DC Analysis of PWM Buck Converter for CCM. 2.3 DC Analysis of PWM Buck Converter for DCM. 2.4 Buck Converter with Input Filter. 2.5 Buck Converter with Synchronous Rectifier. 2.6 Buck Converter with Positive Common Rail. 2.7 Tapped Inductor Buck Converters. 2.8 Multiphase Buck Converter. 2.9 Summary. 2.10 References. 2.11 Review Questions. 2.12 Problems. 3 Boost PWM DC DC Converter. 3.1 Introduction. 3.2 DC Analysis of PWM Boost Converter for CCM. 3.3 DC Analysis of PWM Boost Converter for DCM. 3.4 Bidirectional Buck and Boost Converters. 3.5 Tapped Inductor Boost Converters. 3.6 Duality. 3.7 Power Factor Correction. 3.8 Summary. 3.9 References. 3.10 Review Questions. 3.11 Problems. 4 Buck Boost PWM DC DC Converter. 4.1 Introduction. 4.2 DC Analysis of PWM Buck Boost Converter for CCM. 4.3 DC Analysis of PWM Buck Boost Converter for DCM. 4.4 Bidirectional Buck Boost Converter. 4.5 Synthesis of Buck Boost Converter. 4.6 Synthesis of Boost Buck (Cuk) Converter. 4.7 Noninverting Buck Boost Converters. 4.8 Tapped Inductor Buck Boost Converters. 4.9 Summary. 4.10 References. 4.11 Review Questions. 4.12 Problems. 5 Flyback PWM DC DC Converter. 5.1 Introduction. 5.2 Transformers. 5.3 DC Analysis of PWM Flyback Converter for CCM. 5.4 DC Analysis of PWM Flyback Converter for DCM. 5.5 Multiple Output Flyback Converter. 5.6 Bidirectional Flyback Converter. 5.7 Ringing in Flyback Converter. 5.8 Flyback Converter with Active Clamping. 5.9 Two Transistor Flyback Converter. 5.10 Summary. 5.11 References. 5.12 Review Questions. 5.13 Problems. 6 Forward PWM DC DC Converter. 6.1 Introduction. 6.2 DC Analysis of PWM Forward Converter for CCM. 6.3 DC Analysis of PWM Forward Converter for DCM. 6.4 Multiple Output Forward Converter. 6.5 Forward Converter with Synchronous Rectifier. 6.6 Forward Converters with Active Clamping. 6.7 Two Switch Forward Converter. 6.8 Summary. 6.9 References. 6.10 Review Questions. 6.11 Problems. 7 Half Bridge PWM DC DC Converter. 7.1 Introduction. 7.2 DC Analysis of PWM Half Bridge Converter for CCM. 7.3 DC Analysis of PWM Half Bridge Converter for DCM. 7.4 Summary. 7.5 References. 7.6 Review Questions. 7.7 Problems. 8 Full Bridge PWM DC DC Converter. 8.1 Introduction. 8.2 DC Analysis of PWM Full Bridge Converter for CCM. 8.3 DC Analysis of PWM Full Bridge Converter for DCM. 8.4 Phase Controlled Full Bridge Converter. 8.5 Summary. 8.6 References. 8.7 Review Questions. 8.8 Problems. 9 Push Pull PWM DC DC Converter. 9.1 Introduction. 9.2 DC Analysis of PWM Push Pull Converter for CCM. 9.3 DC Analysis of PWM Push Pull Converter for DCM. 9.4 Comparison of PWM DC DC Converters. 9.5 Summary. 9.6 References. 9.7 Review Questions. 9.8 Problems. 10 Small Signal Models of PWM Converters for CCM and DCM. 10.1 Introduction. 10.2 Assumptions. 10.3 Averaged Model of Ideal Switching Network for CCM. 10.4 Averaged Values of Switched Resistances. 10.5 Model Reduction. 10.6 Large Signal Averaged Model for CCM. 10.7 DC and Small Signal Circuit Linear Models of Switching Network for CCM. 10.8 Family of PWM Converter Models for CCM. 10.9 PWM Small Signal Switch Model for CCM. 10.10 Modeling of the Ideal Switching Network for DCM. 10.11 Averaged Parasitic Resistances for DCM. 10.12 Small Signal Models of PWM Converters for DCM. 10.13 Summary. 10.14 References. 10.15 Review Questions. 10.16 Problems. 11 Open Loop Small Signal Characteristics of Boost Converter for CCM. 11.1 Introduction. 11.2 DC Characteristics. 11.3 Open Loop Control to Output Transfer Function. 11.4 Delay in Open Loop Control to Output Transfer Function. 11.5 Open Loop Audio Susceptibility. 11.6 Open Loop Input Impedance. 11.7 Open Loop Output Impedance. 11.8 Open Loop Step Responses. 11.9 Summary. 11.10 References. 11.11 Review Questions. 11.12 Problems. 12 Voltage Mode Control of Boost Converter. 12.1 Introduction. 12.2 Circuit of Boost Converter with Voltage Mode Control. 12.3 Pulse Width Modulator. 12.4 Transfer Function of Modulator, Boost Converter Power Stage, and Feedback Network. 12.5 Error Amplifier. 12.6 Integral Single Lead Controller. 12.7 Integral Double Lead Controller. 12.8 Loop Gain. 12.9 Closed Loop Control to Output Voltage Transfer Function. 12.10 Closed Loop Audio Susceptibility. 12.11 Closed Loop Input Impedance. 12.12 Closed Loop Output Impedance. 12.13 Closed Loop Step Responses. 12.14 Closed Loop DC Transfer Functions. 12.15 Summary. 12.16 References. 12.17 Review Questions. 12.18 Problems. 13 Current Mode Control. 13.1 Introduction. 13.2 Principle of Operation of PWM Converters with Peak Current Mode Control. 13.3 Relationship between Duty Cycle and Inductor Current Slopes. 13.4 Instability of Closed Current Loop. 13.5 Slope Compensation. 13.6 Sample and Hold Effect on Current Loop. 13.7 Current Loop in s Domain. 13.8 Voltage Loop of PWM Converters with Current Mode Control. 13.9 Feedforward Gains in PWM Converters with Current Mode Control without Slope Compensation. 13.10 Feedforward Gains in PWM Converters with Current Mode Control and Slope Compensation. 13.11 Closed Loop Transfer Functions with Feedforward Gains. 13.12 Slope Compensation by Adding a Ramp to Inductor Current. 13.13 Relationships for Constant Frequency Current Mode On Time Control. 13.14 Summary. 13.15 References. 13.16 Review Questions. 13.17 Problems. 13.18 Appendix: Sample and Hold Modeling. 14 Current Mode Control of Boost Converter. 14.1 Introduction. 14.2 Open Loop Small Signal Transfer Functions. 14.3 Open Loop Step Responses of Inductor Current. 14.5 Closed Voltage Loop Transfer Functions. 14.6 Closed Loop Step Responses. 14.7 Closed Loop DC Transfer Functions. 14.8 Summary. 14.9 References. 14.10 Review Questions. 14.11 Problems. 15 Silicon and Silicon Carbide Power Diodes. 15.1 Introduction. 15.2 Electronic Power Switches. 15.3 Intrinsic Semiconductors. 15.4 Extrinsic Semiconductors. 15.5 Silicon and Silicon Carbide. 15.6 Physical Structure of Junction Diodes. 15.7 Static I V Diode Characteristic. 15.8 Breakdown Voltage of Junction Diodes. 15.9 Capacitances of Junction Diodes. 15.10 Reverse Recovery of pn Junction Diodes. 15.11 Schottky Diodes. 15.12 SPICE Model of Diodes. 15.13 Summary. 15.14 References. 15.15 Review Questions. 15.16 Problems. 16 Silicon and Silicon Carbide Power MOSFETs. 16.1 Introduction. 16.2 Physical Structure of Power MOSFETs. 16.3 Principle of Operation of Power MOSFETs. 16.4 Derivation of Power MOSFET Characteristics. 16.5 Power MOSFET Characteristics. 16.6 Mobility of Charge Carriers. 16.7 Short Channel Effects. 16.8 Aspect Ratio of Power MOSFETs. 16.9 Breakdown Voltage of Power MOSFETs. 16.10 Gate Oxide Breakdown Voltageof Power MOSFETs. 16.11 Resistance of Drift Region. 16.12 Figures of Merit. 16.13 On Resistance of Power MOSFETs. 16.14 Capacitances of Power MOSFETs. 16.15 Switching Waveforms. 16.16 SPICE Model of Power MOSFETs. 16.17 Insulated Gate Bipolar Transistors. 16.18 Heat Sinks. 16.19 Summary. 16.20 References. 16.21 Review Questions. 16.22 Problems. 17 Soft Switching DC DC Converters. 17.1 Introduction. 17.2 Zero Voltage Switching DC DC Converters. 17.3 Buck ZVS Quasi Resonant DC DC Converter. 17.4 Boost ZVS Quasi Resonant DC DC Converter. 17.5 Zero Current Switching DC DC Converters. 17.6 Boost ZCS Quasi Resonant DC DC Converter. 17.7 Multiresonant Converters. 17.8 Summary. 17.9 References. 17.10 Review Questions. 17.11 Problems. Appendix A Introduction to SPICE. Appendix B Introduction to MATLAB. Answers to Problems. Index.", "author_names": [ "Marian K Kazimierczuk" ], "corpus_id": 109665295, "doc_id": "109665295", "n_citations": 655, "n_key_citations": 81, "score": 1, "title": "Pulse Width Modulated DC DC Power Converters", "venue": "", "year": 2008 }, { "abstract": "", "author_names": [ "Marian K Kazimierczuk" ], "corpus_id": 63476315, "doc_id": "63476315", "n_citations": 331, "n_key_citations": 0, "score": 0, "title": "Pulse Width Modulated DC DC Power Converters: Kazimierczuk/Pulse width Modulated DC DC Power Converters", "venue": "", "year": 2008 }, { "abstract": "", "author_names": [ "Marian K Kazimierczuk" ], "corpus_id": 113885783, "doc_id": "113885783", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Pulse Width Modulated DC DC Power Converters: Kazimierczuk/Pulse Width", "venue": "", "year": 2013 }, { "abstract": "Visible light communication (VLC) has gained relevance during the last few years. It consists in using high brightness LEDs (HB LEDs) both for lighting and transmitting information by changing the light intensity rapidly. However, there are some bottlenecks that are slowing down the deployment of this technology. One of the most important problems is that the HB LED drivers proposed for addressing high data rates in VLC achieve poor power efficiency. Since these HB LED drivers must be able to reproduce fast current waveforms, the use of linear power amplifiers has been adopted, which clearly damages the power efficiency of HB LED lighting. In order to alleviate this problem, an HB LED driver made up of two DC DC power converters is presented in this work. One of them is responsible for performing the communication functionality by operating at high switching frequency (10 MHz) whereas the second converter fulfills the illumination functionality by ensuring a certain biasing point. The split of the power allows us to minimize the power delivered by the fast response DC DC power converter, which suffers from high switching losses. Thus, the overall efficiency can be maximized for each particular communication scenario and for scenarios with changing conditions (i.e. mobile transmitter and/or receiver, presence of mobile obstacles, etc. In this sense, how the lighting level and the communication signal power affect both the power efficiency and the communication efficiency is deeply analyzed in the experimental section. The implemented prototype achieves an overall efficiency around 90% In addition, the proposed VLC transmitter is able to reproduce a wide range of digital modulation schemes, including the preferred one for wireless communications: orthogonal frequency division multiplexing.", "author_names": [ "Juan Rodriguez", "Diego G Lamar", "Pablo Fernandez Miaja", "Daniel Garcia Aller", "Javier Sebastian" ], "corpus_id": 56596251, "doc_id": "56596251", "n_citations": 19, "n_key_citations": 1, "score": 0, "title": "Power Efficient VLC Transmitter Based on Pulse Width Modulated DC DC Converters and the Split of the Power", "venue": "IEEE Transactions on Power Electronics", "year": 2019 }, { "abstract": "This book is a comprehensive textbook in the areas of electrical, electronics, and telecommunications engineering. It consists of 17 chapters and two appendices. Some of the topics covered include: buck PWM DC DC converters; boost PWM DC DC converters; buck boost PWM DC DC converters; half bridge and full bridge converters; push pull PWM DC DC converters; open loop small signal characteristics of boost converters for CCM; current mode control of boost converters; silicon and silicon carbide power diodes; and soft switching DC DC converters. Appendix A is an introduction to SPICE and Appendix B provides an introduction to MATLAB. Answers to problems and the index are also included at the end of the book. The book is recommended for senior undergraduate and graduate students but also for practicing engineers working with switch mode power supplies, within applications such as computers, telecommunications, industrial electronic systems, automobile electronics, medical equipment, radars, and aerospace power technology.", "author_names": [ "Marian P Kazmierkowski" ], "corpus_id": 29870901, "doc_id": "29870901", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Power converters and amplifiers (review of \"Pulse Width Modulated DC DC Power Converters\" by Kazimierczuk, M.K. 2008) [Book News]", "venue": "IEEE Industrial Electronics Magazine", "year": 2009 }, { "abstract": "A general expression for winding loss (copper loss) including harmonics for an inductor carrying periodic non sinusoidal current is presented. The skin and proximity effects are taken into account. Expressions for amplitudes of inductor current harmonics are derived and illustrated as functions of duty cycle for selected non isolated converters namely buck, boost and buck boost converters. An example of inductor design procedure using the area product method is shown for a buck converter operating in continuous conduction mode (CCM) The amplitude spectra of the inductor current, winding resistance and winding power loss are illustrated. Inductor winding losses in the designed inductor are analysed using MatLab simulations. Experimental results using the designed inductor are also presented.", "author_names": [ "Nisha Kondrath", "Marian K Kazimierczuk" ], "corpus_id": 110945124, "doc_id": "110945124", "n_citations": 74, "n_key_citations": 2, "score": 0, "title": "Inductor winding loss owing to skin and proximity effects including harmonics in non isolated pulse width modulated dc dc converters operating in continuous conduction mode", "venue": "", "year": 2010 }, { "abstract": "High frequency (HF) transformers used in pulse width modulated power converters conduct periodic non sinusoidal HF currents, which give rise to additional winding losses caused by harmonics. This study presents expressions for winding power losses in a two winding transformer with periodic non sinusoidal primary and secondary current waveforms for flyback converters operating in the continuous conduction mode (CCM) Dowell's equation, which takes into account both the skin and proximity effects, is used to determine the primary and secondary winding resistances as functions of frequency. Fourier series of the primary and secondary current waveforms and the winding resistances are used to determine the winding power losses at harmonic frequencies. The harmonic primary and secondary winding loss factors FRph and FRsh are introduced for CCM operation. The theory is illustrated by performance evaluation of the transformer in a flyback converter in CCM over the entire range of converter operation. Power losses in the primary and secondary transformer windings are illustrated as functions of the output power and the DC input voltage.", "author_names": [ "Dakshina Murthy-Bellur", "Nisha Kondrath", "Marian K Kazimierczuk" ], "corpus_id": 110405898, "doc_id": "110405898", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Transformer winding loss caused by skin and proximity effects including harmonics in pulse width modulated DC?DC flyback converters for the continuous conduction mode", "venue": "", "year": 2011 }, { "abstract": "General equation for the control current for the inner current loop of pulse width modulated (PWM) dc dc power converters with peak current mode control without slope compensation is derived. Derivations of expressions for the control current as functions of duty cycle and phase margin at power stage specifications for buck, boost and buck boost dc dc converters in continuous conduction mode (CCM) are presented. Relative stability of the inner current loop without slope compensation was analysed. Experimental and Saber simulation results for a buck converter with the inner current loop are presented to validate the theory presented. The results obtained can be used to determine the range of control voltage required by the inner loop, to select a proper value of sense resistance, and to design the control circuit in the outer voltage loop of peak current mode controlled PWM DC DC converters. It is shown that the phase margin of the inner loop is 0 at a duty cycle value of 0.5 and increases as the duty cycle decreases.", "author_names": [ "Nisha Kondrath", "Marian K Kazimierczuk" ], "corpus_id": 108504585, "doc_id": "108504585", "n_citations": 40, "n_key_citations": 1, "score": 0, "title": "Control current and relative stability of peak current mode controlled pulse width modulated dc dc converters without slope compensation", "venue": "", "year": 2010 }, { "abstract": "High frequency transformers used in pulse width modulated (PWM) converters conduct periodic non sinusoidal currents, which give rise to additional winding losses because of harmonics. This study presents expressions for winding power losses in a two winding transformer subject to non sinusoidal excitation operated in discontinuous conduction mode (DCM) Dowell's equation is used to determine the winding resistances because of eddy currents as a function of frequency. Both skin and proximity effects are taken into account. Fourier series of the primary and secondary triangular current waveforms in isolated dc dc power converters and the primary and secondary winding resistances are used to determine the primary and secondary winding power losses at various harmonics, respectively. The harmonic winding loss factors FRph and FRsh are introduced. The theory is illustrated by the case study of the two winding flyback converter operating in DCM. Plots of the winding power losses are given as functions of the output power and the dc input voltage.", "author_names": [ "Dakshina Murthy-Bellur", "Marian K Kazimierczuk" ], "corpus_id": 109198971, "doc_id": "109198971", "n_citations": 38, "n_key_citations": 3, "score": 0, "title": "Winding losses caused by harmonics in high frequency flyback transformers for pulse width modulated dc dc converters in discontinuous conduction mode", "venue": "", "year": 2010 }, { "abstract": "This paper describes the design and implementation of zero voltage transition (ZVT) pulse width modulated (PWM) bidirectional buck boost converter. The simplicity of the control and the reduction of voltage and current stresses on the main switches are the main features of the proposed converter. The additional component of the converter consists of two auxiliary switches and coupled inductors. They provide a zero voltage switching condition for all switching elements regardless of the power flow direction, making the energy conversion highly efficient. The calculated efficiency of the suggested converter is more than 96% at full load in both buck and boost modes. In addition, the same auxiliary circuit can be used in other basic non isolated bidirectional converters such as Cuk, Sepic/Zeta, buck boost/buck boost and cascade buck boost converters to provide soft switching. A 100 W prototype of the proposed converter is implemented. The simulation and experimental results are found closely comparable and confirm the effectiveness of the proposed method.", "author_names": [ "Amin Mirzaei", "Awang Jusoh", "Zainal Salam" ], "corpus_id": 108817904, "doc_id": "108817904", "n_citations": 31, "n_key_citations": 1, "score": 0, "title": "Design and implementation of high efficiency non isolated bidirectional zero voltage transition pulse width modulated DC DC converters", "venue": "", "year": 2012 } ]

[ { "abstract": "Abstract Powerful and versatile transistors are indispensable to realize the vision of future flexible electronics, e.g. for wearable active matrix displays, smart sensors, or RFID tags. Organic thin film transistors are considered to be a perfect match for flexible electronics. However, conventional organic thin film transistors (OTFTs) still do not match the demanding performance targets of many applications. Furthermore, often complex and expensive fabrication steps are employed for the fabrication of hero devices, which is not compatible with the paradigm of low cost production of flexible electronics. In this contribution, we present the first solution processed vertical organic field effect transistor (VOFET) with good on state performance comparable to vacuum processed VOFETs. This approach unites the advantages of a low temperature, low cost solution processing with an ultra short channel transistor concept possibly enabling large area, low cost flexible electronics. We examine the influence of different crystal morphologies (spherulitic, ribbons) on the transistor performance by using spin and shear coating as solution based deposition methods. The solution processed VOFETs reach channel width normalized transconductances of up to 0.26 mS/mm with a charge carrier mobility of 4.8 cm2/Vs. S parameter measurements finally verify that transition frequencies up to 6 MHz are reachable with shear coated TIPS pentacene. However, compared to small molecule based VOFETs, the solution processed VOFETs show an unfavorably high off state current and hysteresis which are explained by background doping and charge carrier trapping. Hence, in order to advance with, further optimization of the semiconductor material and the insulator semiconductor interface are thus required to qualify solution processed VOFETs for commercial applications.", "author_names": [ "David Kneppe", "Felix Talnack", "Bahman Kheradmand Boroujeni", "Cecilia Teixeira da Rocha", "Marc Hoppner", "Alexander Tahn", "Stefan C B Mannsfeld", "Frank Ellinger", "Karl Leo", "Hans Kleemann" ], "corpus_id": 233792854, "doc_id": "233792854", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Solution processed pseudo vertical organic transistors based on TIPS pentacene", "venue": "", "year": 2021 }, { "abstract": "The development of nonvolatile organic field effect transistor (OFET) memories with a satisfactory solution processability is highly desirable to fabricate the data storage media for flexible and printed electronic devices. In this study, we fabricate top gate/bottom contact OFET memories having an organic floating gate structure by a spin coating process and investigate their memory characteristics. An ambipolar polymer semiconductor of poly(N alkyldiketopyrrolo pyrrole dithienylthieno[3,2 b]thiophene) (DPP DTT) was used to fabricate an organic semiconductor layer, on which an organic composite of polystyrene and 6,13 bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) was deposited to form an organic floating gate structure through vertical phase separation. The existence of a deep lowest unoccupied molecular orbital (LUMO) level and the excellent electron transport property of the DPP DTT enables the injection of electrons from the Au source drain electrodes to the DPP DTT semiconductor layer and the storage of electrons in the LUMO level of the TIPS pentacene floating gates by programming under dark conditions. A high work function metal oxide layer of MoO3 was inserted at the Al gate electrode/CYTOP gate insulator interface to tune the energy level difference between the Au source drain and Al gate electrodes. The DPP DTT FET memories with MoO3/Al gate electrodes exhibit satisfactory retention characteristics and, because of the ambipolar trapping characteristics, allow the storing of holes in the highest occupied molecular orbital level of the TIPS pentacene floating gates in the erasing process. Furthermore, the molecular floating gate OFET memories exhibit a high storage capacity for multi level data, and four state levels can be recorded with stable retention characteristics.", "author_names": [ "Miho Higashinakaya", "Takashi Nagase", "Hayato Abe", "Reitaro Hattori", "Shion Tazuhara", "Takashi Kobayashi", "Hiroyoshi Naito" ], "corpus_id": 233708391, "doc_id": "233708391", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Electrically programmable multilevel nonvolatile memories based on solution processed organic floating gate transistors", "venue": "", "year": 2021 }, { "abstract": "Abstract In this study, we report a facile route to regulate the crystallization and enhance charge transport of small molecule organic semiconductors by blending with a rubbery polymer additive polyisobutylene (PIB) Using a solution processed semiconductor 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) to mix with the PIB polymer, we show that the addition of PIB led to densely arranged, lengthened TIPS pentacene needles with excellent long range uniformity. Bottom gate, top contact organic thin film transistors (OTFTs) based on TIPS pentacene/PIB hybrid film demonstrated a field effect mobility of up to 0.15 cm2/Vs, and particularly, a 3 fold and 2 fold enhancement of average mobility and performance consistency (denoted by average mobility to standard deviation ratio) In addition, the effect of hexamethyldisilazane (HMDS) surfactant treatment on the semiconductor charge transport was studied. We ascribe such improved performance of TIPS pentacene/PIB blend OTFTs to the collaborative outcome of reduced crystal misorientation, diminished defects and charge trap centers, as well as a higher areal coverage. The effective method as demonstrated in this work can be generally implemented to attune the crystal growth and promote charge transport of newly developed small molecule organic semiconductors.", "author_names": [ "Zhengran He", "Ziyang Zhang", "Sheng Bi", "Kyeiwaa Asare-Yeboah", "Jihua Chen", "Dawen Li" ], "corpus_id": 214198908, "doc_id": "214198908", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "A facile and novel route to improve TIPS pentacene based organic thin film transistor performance with elastomer", "venue": "", "year": 2020 }, { "abstract": "The blending of the crystalline organic semiconductor, 6,13 bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) with amorphous polymers exhibits not only excellent solution processability, but also superior performance characteristics in organic thin film transistors (OTFTs) To understand the inkjet printing behavior of TIPS pentacene/polymer blends, we use amorphous polycarbonate (APC) which is structurally beneficial to the facile phase separation of TIPS pentacene crystals due to the strong segregation strength estimated by the Flory Huggins interaction parameter. The various inkjet printing behaviors of TIPS pentacene/APC inks, which depend on the TIPS pentacene/APC compositions, ink viscosities, and different solvent mixtures, are investigated. These behaviors can ultimately determine the phase separation, morphology, shape, and orientation of the TIPS pentacene crystals in OTFT films. Flory Huggins phase separation theory is applied, and various analytical methods, such as polarized optical microscopy, 3D surface profile, and time of flight secondary ion mass spectroscopy (TOF SIMS) are utilized to explain these relationships. By controlling these inkjet printing conditions, it is possible to easily regulate the optimal inkjet printing process for TIPS pentacene/polymer systems, which can derive the desirable stripe shaped and vertically phase separated TIPS pentacene crystals with the proper orientation and enhanced surface morphology. The resultant inkjet printed films from the TIPS pentacene with APC show excellent device stability and an average mobility of 0.53 cm2 V 1 s 1. Furthermore, the inkjet printed flexible OTFT array with an average mobility of 0.27 cm2 V 1 s 1 sustains the application of TIPS pentacene/APC in the field of flexible printed electronics.", "author_names": [ "Song Yun Cho", "J M Ko", "Jongsun Lim", "Jun Young Lee", "Changjin Lee" ], "corpus_id": 137095056, "doc_id": "137095056", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Inkjet printed organic thin film transistors based on TIPS pentacene with insulating polymers", "venue": "", "year": 2013 }, { "abstract": "In this study, we demonstrated for the first time that a metal containing semicrystalline polymer was used as an additive to mediate the thin film morphology of solution grown, small molecule organic semiconductors. By mixing polyferrocenylsilane (PFS) with an extensively studied organic semiconductor 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) PFS as a semicrystalline polymer independently forms nucleation and crystallization while simultaneously ameliorating diffusivity of the blend system and tuning the surface energies as a result of its partially amorphous property. We discovered that the resultant blend film exhibited a 6 fold reduction in crystal misorientation angle and a 3 fold enlargement in average grain width. Enhanced crystal orientation considerably reduces mobility variation, while minimized defects and trap centers located at grain boundaries lessen the adverse impact on the charge transport. Consequently, bottom gate, top contact organic thin film transistors (OTFTs) based on the TIPS pentacene/PFS mixture yielded a 40% increase in performance consistency (represented by the ratio of average mobility to the standard deviation of mobility) The PFS semicrystalline polymer controlled crystallization can be used to regulate the thin film morphology of other high performance organic semiconductors and shed light on applications in organic electronic devices.", "author_names": [ "Zhengran He", "Ziyang Zhang", "Kyeiwaa Asare-Yeboah", "Sheng Bi", "Jihua Chen", "Dawen Li" ], "corpus_id": 231764070, "doc_id": "231764070", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Polyferrocenylsilane Semicrystalline Polymer Additive for Solution Processed p Channel Organic Thin Film Transistors", "venue": "Polymers", "year": 2021 }, { "abstract": "Despite solution processed organic semiconductors have attracted much research attention, the randomized crystallization and large prevalence of grain boundary remain as a challenge to realize high performance organic electronic applications. In this work, we report the incorporation of poly(butyl acrylate) polymer additive with organic semiconductors with the mediation of a solvent vapor annealing method in order to modify the nucleation and crystal growth process. As 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) was experimented as a benchmark semiconductor, we demonstrated that the TIPS pentacene/poly(butyl acrylate) mixture exhibits rigidly aligned crystals, large grain width and improved areal coverage. In particular, thin film morphological characterization indicated a substantial reduction in misorientation angle by approximately two orders of magnitude as well as a 5 fold enlargement of grain width. A grain boundary model is proposed as a theoretic basis to understand the connection between grain width and hole mobility. Bottom gate, top contact thin film transistors based on TIPS pentacene/poly(butyl acrylate) blends demonstrated enhanced hole mobility of up to 0.11 cm2/Vs.", "author_names": [ "Yeqing Sun", "Ziyang Zhang", "Kyeiwaa Asare-Yeboah", "Sheng Bi", "Zhengran He" ], "corpus_id": 224827282, "doc_id": "224827282", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Large Dimensional Organic Semiconductor Crystals with Poly(butyl acrylate) Polymer for Solution Processed Organic Thin Film Transistors", "venue": "Electronic Materials Letters", "year": 2020 }, { "abstract": "Electrolyte gated organic field effect transistors (EGOFETs) have been fabricated using 6,13 Bis (triisopropyl silylethynyl) pentacene (TIPS pentacene) as an organic semiconductor active material. Despite the organic semiconductor being deposited in air by drop casting, our EGOFETs showed performance comparable with state of the art technologies, and devices kept their functionalities while gated with saline solution at 37 degC for several days. In addition, the biocompatibility of the material was successfully investigated, promoting the use of TIPS pentacene based EGOFETs for biosensing applications.", "author_names": [ "Nicolo Lago", "Marco Buonomo", "Saima Imran", "Roberta Bertani", "Nicola Wrachien", "Mario Bortolozzi", "Morten G Pedersen", "Andrea Cester" ], "corpus_id": 52116083, "doc_id": "52116083", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "TIPS Pentacene as Biocompatible Material for Solution Processed High Performance Electronics Operating in Water", "venue": "IEEE Electron Device Letters", "year": 2018 }, { "abstract": "Abstract In this study, we achieved high performance organic small molecule transistors by using roll to roll slot die coating technique and polymer dielectric layers. By carefully controlling the coating conditions, highly ordered single crystalline thin films could be achieved. Hence, the organic thin film transistor (OTFT) device exhibited an average mobility of 4.2 cm2V 1s 1 and maximum mobility of 6.5 cm2V 1s 1 based on polystyrene (PS) dielectric layer in the ambient air condition, which is among the best values for TIPS pentacene based devices. The thin film morphology, crystallinity, and optical properties were studied in details. A complementary inverter based on p type TIPS pentacene and n type 6,13 Dicyano pentacene 2,3:9,10 bis(dicarboximide) (PDI CN) with a high voltage gain of 54 was achieved. Finally, the flexible devices based on roll to roll slot die coated PS dielectric and TIPS pentacene were achieved with a charge carrier mobility of 1.2 cm2V 1s 1.", "author_names": [ "Zhenhua Lin", "Xing Guo", "Long Zhou", "Chunfu Zhang", "Jingjing Chang", "Jishan Wu", "Jie Zhang" ], "corpus_id": 102835475, "doc_id": "102835475", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Solution processed high performance organic thin film transistors enabled by roll to roll slot die coating technique", "venue": "", "year": 2018 }, { "abstract": "We demonstrated an organic and oxide hybrid CMOS inverter with the solution processed semiconductor and source/drain electrodes. For the solution processed n and p type semiconductor, InGaZnO solution and TIPS pentacene/PaMS blend were spin coated respectively while Silver ink and PEDOT:PSS solution were drop casted with the help of the bank to serve as source/drain electrodes. The InGaZnO and the TIPS pentacene transistors show typical n and p type transistor operations with low off current. Based on the combination of the solution processed n and p type transistors, full swing characteristic curve with low static current of the hybrid CMOS were obtained.", "author_names": [ "Sunghun Lee", "Min-Jae Seo", "Amos Amoako Boampong", "Jae-Hyeok Cho", "Kyeong Min Yu", "Min-Hoi Kim" ], "corpus_id": 210865484, "doc_id": "210865484", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Solution Processed Organic and Oxide Hybrid CMOS Inverter for Low Cost Electronic Circuits.", "venue": "Journal of nanoscience and nanotechnology", "year": 2020 }, { "abstract": "We demonstrated a new type of a solution processed organic field effect transistor (OFET) in a bottom gate, top contact geometry where low leakage current and self pattern registration were achieved using a patterned dielectric barrier (PDB) The PDB of a hydrophobic fluorinated polymer was produced on the top of a polymeric gate insulator of poly(4 vinylphenyl) by transfer printing. The PDB enables to effectively screen out the vertical charge flow generated from the gate electrode, and thus the vertical leakage current between the gate and the drain was reduced by two orders of the magnitude compared to the leakage current in a conventional OFET without the PDB. Moreover, the PDB defines spontaneously an active channel pattern from a solution of 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS PEN) by means of the selective wettability and the geometrical confinement.", "author_names": [ "Changmin Keum", "Jin-Hyuk Bae", "Min-Hoi Kim", "Won-Suk Choi", "Sin Doo Lee" ], "corpus_id": 54761833, "doc_id": "54761833", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Solution processed low leakage organic field effect transistors with self pattern registration based on patterned dielectric barrier", "venue": "", "year": 2012 } ]

[ { "abstract": "The systematic analysis of ever increasing data collection presents companies with ever greater challenges. Many manufacturing organizations simply lack the know how to handle Big Data projects and the corresponding data analysis right. Therefore one simply follows the current trends and buzz words and adopts approaches which are currently en vogue. This approach often leads to less successful projects and several regularly reoccurring patterns of misconceptions can be identified. This paper highlights some of these unsuccessful patterns and introduces some of the work done in the PRO OPT SMART DATA research project. The innovation in this data analysis approach is the combination of traditional statistical methods with new Big Data and AI analysis techniques applied to high tech manufacturing. Being able to align process data with the complete metrology data provides amazing new insights into the manufacturing. Furthermore, we will introduce a new visualization technique specifically suited for domains with high amounts of categorical data like semiconductor, photovoltaics, electronics and such. This paper will show how the combination of the statistical data analysis system Cornerstone in conjunction with Apache Spark1 and Apache Cassandra2 provides a good basis for engineering analytics of massive data amounts. By properly nesting the solid mathematical methods in Cornerstone with big data appropriate infrastructure such as Apache Spark and, in our case, Apache Cassandra, many new analytics issues can be addressed. Analyzes that used to be inefficient due to the sheer volume of data in classically modeled schema's can now be performed through appropriate big table modeling and provide the ability to provide completely new insights into production data. Those directly impacted the manufacturing procedures and improved the products quality and reliability. Experiences gained in the project impacted the upcoming VDI/VDE guideline 37143 to be published later in the year 2019.", "author_names": [ "Dirk Ortloff", "Nils Knoblauch" ], "corpus_id": 202559019, "doc_id": "202559019", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Applying big data technologies to high tech manufacturing", "venue": "European Mask and Lithography Conference", "year": 2019 }, { "abstract": "Both spin orbit states of C2H5I+ the X1 2E1/2 and the X2 2E1/2 electronic states, are studied by one color two photon ionization of ethyl iodide, utilizing the zero kinetic energy pulsed field ionization (ZEKE PFI) photoelectron technique. Compared with conventional photoelectron data the two photon spectra exhibit a more extensive vibrational structure mainly involving the C I stretching and the C C I bending modes. This additional vibrational excitation in the two photon spectra is discussed in terms of mode selective resonance enhancement by the dissociative A state continuum. Accurate values for the vibrational frequencies and the ionization energies are obtained. The appearance of nontotally symmetric modes in the two color ZEKE spectra is reported.", "author_names": [ "Nils Knoblauch", "Andreas Strobel", "Ingo Fischer", "Vladimir E Bondybey" ], "corpus_id": 94866597, "doc_id": "94866597", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Two photon ionization and dissociation of ethyl iodide", "venue": "", "year": 1995 }, { "abstract": "", "author_names": [ "Andreas Strobel", "Nils Knoblauch", "J Agreiter", "Andrew M Smith", "Gereon Niedner-Schatteburg", "Vladimir E Bondybey" ], "corpus_id": 95352446, "doc_id": "95352446", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Identification, Structure, and Vibrational Assignment of the NO Dimer Cation", "venue": "", "year": 1995 }, { "abstract": "Key messageA first set of 25 NILs carrying ten BPH resistance genes and their pyramids was developed in the background of indica variety IR24 for insect resistance breeding in rice.AbstractBrown planthopper (Nilaparvata lugens Stal. is one of the most destructive insect pests in rice. Development of near isogenic lines (NILs) is an important strategy for genetic analysis of brown planthopper (BPH) resistance (R) genes and their deployment against diverse BPH populations. A set of 25 NILs with 9 single R genes and 16 multiple R gene combinations consisting of 11 two gene pyramids and 5 three gene pyramids in the genetic background of the susceptible indica rice cultivar IR24 was developed through marker assisted selection. The linked DNA markers for each of the R genes were used for foreground selection and confirming the introgressed regions of the BPH R genes. Modified seed box screening and feeding rate of BPH were used to evaluate the spectrum of resistance. BPH reaction of each of the NILs carrying different single genes was variable at the antibiosis level with the four BPH populations of the Philippines. The NILs with two to three pyramided genes showed a stronger level of antibiosis (49.3 99.0% against BPH populations compared with NILs with a single R gene NILs (42.0 83.5% and IR24 (10.0% Background genotyping by high density SNPs markers revealed that most of the chromosome regions of the NILs (BC3F5) had IR24 genome recovery of 82.0 94.2% Six major agronomic data of the NILs showed a phenotypically comparable agronomic performance with IR24. These newly developed NILs will be useful as new genetic resources for BPH resistance breeding and are valuable sources of genes in monitoring against the emerging BPH biotypes in different rice growing countries.", "author_names": [ "Kshirod K Jena", "Sherry Lou Hechanova", "Holden Verdeprado", "G D Prahalada", "Sung-Ryul Kim" ], "corpus_id": 40261647, "doc_id": "40261647", "n_citations": 31, "n_key_citations": 5, "score": 0, "title": "Development of 25 near isogenic lines (NILs) with ten BPH resistance genes in rice (Oryza sativa L. production, resistance spectrum, and molecular analysis", "venue": "Theoretical and Applied Genetics", "year": 2017 }, { "abstract": "Rezension von: Rene Tuma Bernt Schnettler Hubert Knoblauch: Videographie. Einfuhrung in die interpretative Videoanalyse sozialer Situationen. Wiesbaden: Springer VS 2013, 135 S. ISBN 978 3 531 18731 0", "author_names": [ "Sales Severin Rodel" ], "corpus_id": 165679967, "doc_id": "165679967", "n_citations": 73, "n_key_citations": 0, "score": 0, "title": "Rene/Schnettler, Bernt/Knoblauch, Hubert: Videographie, Einfuhrung in die interpretative Videoanalyse sozialer Situationen. Wiesbaden: Springer VS 2013. [Rezension]", "venue": "", "year": 2014 }, { "abstract": "Magnaporthe oryzae infection causes rice blast, a destructive disease that is responsible for considerable decrease in rice yield. Development of resistant varieties via introgressing resistance genes with marker assisted breeding can eliminate pesticide use and minimize crop losses. Here, resistant near isogenic line (NIL) of Pusa Basmati 1(PB1) carrying broad spectrum rice blast resistance gene Pi9 was used to investigate Pi9 mediated resistance response. Infected and uninfected resistant NIL and susceptible control line were subjected to RNA Seq. With the exception of one gene (Pi9) transcriptional signatures between the two lines were alike, reflecting basal similarities in their profiles. Resistant and susceptible lines possessed 1043 (727 up regulated and 316 down regulated) and 568 (341 up regulated and 227 down regulated) unique and significant differentially expressed loci (SDEL) respectively. Pathway analysis revealed higher transcriptional activation of kinases, WRKY, MYB, and ERF transcription factors, JA ET hormones, chitinases, glycosyl hydrolases, lipid biosynthesis, pathogenesis and secondary metabolism related genes in resistant NIL than susceptible line. Singular enrichment analysis demonstrated that blast resistant NIL is significantly enriched with genes for primary and secondary metabolism, response to biotic stimulus and transcriptional regulation. The co expression network showed proteins of genes in response to biotic stimulus interacted in a manner unique to resistant NIL upon M. oryzae infection. These data suggest that Pi9 modulates genome wide transcriptional regulation in resistant NIL but not in susceptible PB1. We successfully used transcriptome profiling to understand the molecular basis of Pi9 mediated resistance mechanisms, identified potential candidate genes involved in early pathogen response and revealed the sophisticated transcriptional reprogramming during rice M. oryzae interactions.", "author_names": [ "Priyanka Caroline Jain", "Pankaj Kumar Singh", "Ritu Kapoor", "Apurva Khanna", "Amol Kumar U Solanke", "Subbaiyan Gopala Krishnan", "Ashutosh Kumar Singh", "Vinay Sharma", "Tilak Raj Sharma" ], "corpus_id": 768607, "doc_id": "768607", "n_citations": 25, "n_key_citations": 2, "score": 0, "title": "Understanding Host Pathogen Interactions with Expression Profiling of NILs Carrying Rice Blast Resistance Pi9 Gene", "venue": "Front. Plant Sci.", "year": 2017 }, { "abstract": "The landscape level and multiscale biodiversity monitoring program National Inventory of Landscapes in Sweden (NILS) was launched in 2003. NILS is conducted as a sample based stratified inventory that acquires data across several spatial scales, which is accomplished by combining aerial photo interpretation with field inventory. A total of 631 sample units are distributed across the land base of Sweden, of which 20% are surveyed each year. By 2007 NILS completed the first 5 year inventory phase. As the reinventory in the second 5 year phase (2008 2012) proceeds, experiences and insights accumulate and reflections are made on the setup and accomplishment of the monitoring scheme. In this article, the emphasis is placed on background, scope, objectives, design, and experiences of the NILS program. The main objective to collect data for and perform analyses of natural landscape changes, degree of anthropogenic impact, prerequisites for natural biological diversity and ecological processes at landscape scale. Different environmental conditions that can have direct or indirect effects on biological diversity are monitored. The program provides data for national and international policy and offers an infrastructure for other monitoring program and research projects. NILS has attracted significant national and international interest during its relatively short time of existence; the number of stakeholders and cooperation partners steadily increases. This is constructive and strengthens the incentive for the multiscale monitoring approach.", "author_names": [ "Goran Stahl", "Anna Allard", "Per-Anders Esseen", "Anders Glimskar", "Anna Ringvall", "Johan Svensson", "Sture Sundquist", "Pernilla Christensen", "Asa Gallegos Torell", "Mats Hogstrom", "Kjell Lagerqvist", "Liselott Marklund", "Bjorn Nilsson", "Ola Inghe" ], "corpus_id": 207130027, "doc_id": "207130027", "n_citations": 135, "n_key_citations": 19, "score": 0, "title": "National Inventory of Landscapes in Sweden (NILS) scope, design, and experiences from establishing a multiscale biodiversity monitoring system", "venue": "Environmental monitoring and assessment", "year": 2011 }, { "abstract": "Heterogeneous inbred families segregating for rust resistance were identified from the two crosses involving susceptible (TAG 24 and TG 26) and resistant (GPBD 4) varieties of peanut. Rust resistant (less than score 5) and rust susceptible (more than score 5) plants were identified in each HIF and evaluated under rust epiphytotic conditions. The set of plants belonging to the same HIF, but differing significantly in rust resistance, not in other morphological and productivity traits, was regarded as near isogenic lines (NILs) Largely, rust resistant NILs had GPBD 4 type allele, and susceptible NILs carried either TAG 24 or TG 26 type allele at the three SSR loci (IPAHM103, GM1536 and GM2301) linked to a major genomic region governing rust resistance. Comparison of the remaining genomic regions between the NILs originating from each of the HIFs using transposon markers indicated a considerably high similarity of 86.4% and 83.1% in TAG 24 x GPPBD 4 and TG 26 x GPBD 4, respectively. These NILs are useful for fine mapping and expression analysis of rust resistance.", "author_names": [ "Sharanabasappa B Yeri", "Kenta Shirasawa", "Manish K Pandey", "Makanahally V C Gowda", "V Sujay", "Manda Shriswathi", "Hajisaheb L Nadaf", "Babu N Motagi", "S Lingaraju", "Anil Bhat", "Rajeev Kumar Varshney", "P U Krishnaraj", "Ramesh S Bhat" ], "corpus_id": 84446855, "doc_id": "84446855", "n_citations": 20, "n_key_citations": 1, "score": 0, "title": "Development of NILs from heterogeneous inbred families for validating the rust resistance QTL in peanut (Arachis hypogaea L.", "venue": "", "year": 2014 }, { "abstract": "Northern Ireland has traditionally been well served with cross sectional studies, including episodic surveys of poverty and social exclusion, and of health and social well being. However, such studies are of limited use in either analysis of life course transitions or in the separation of cause and effect, both important goals of current research strategies where renewed interest in equity and social exclusion is stimulating research into the effects of disadvantage on individuals over time. This is all the more urgent given the increased social and geographical mobility and greater fluidity in people's lives. Such information can only be derived longitudinally, and there was a dearth of such large scale general purpose studies in Northern Ireland. Information had not been included in the three British Birth Cohort studies of 1946, 1958 and 1970 and although other longitudinal studies, such as PRIME and Young Hearts, are available they were designed to answer research questions related to specific diseases. Although the British Household Panel Study has recently been extended to include Northern Ireland and there is now a Northern Ireland component to the Millennium Birth Cohort Study, neither is large enough to function as a general purpose longitudinal study to meet the general research or policy needs of Northern Ireland. In the early 2000s, a group of senior statisticians from the Northern Ireland Statistics and Research Agency (NISRA) and academics was convened to estimate the cost of a Northern Ireland Longitudinal Study (NILS) equivalent to others either already available in England and Wales or, at the time, in development in Scotland. The aim was to have a multi cohort study that would fulfil a range of academic and policy related purposes, with a sample size large enough to enable robust analysis of population sub groups and of areas of policy relevance. Because the experience of the Scottish Longitudinal Study (SLS) team had shown that linkage to the 1991 census would incur considerable costs, especially if social class for earlier years had to be recoded to the NS SEC classification used in the 2001 census, it was decided to start with the 2001 census. Funding for the establishment and maintenance of NILS (and its sister study NIMS, see below) was jointly secured in 2003 from the Department of Health, Social Services and Public Safety and the Research and Development Office of the then Health and Personal Social Services. All funding for the development and maintenance of NILS and NIMS now comes from the Health and Social Care Research and Development Division of the Public Health Agency (HSC R&D Division) NISRA helps to fund the NILS/ NIMS project both through the provision of accommodation to house all aspects of the NILS/NIMS operation and staff to maintain and develop the databases and provide strategic management of the project. Both NILS and NIMS were launched in December 2006.", "author_names": [ "Dermot O'Reilly", "Michael Rosato", "G Catney", "F Johnston", "Maire Brolly" ], "corpus_id": 12515237, "doc_id": "12515237", "n_citations": 71, "n_key_citations": 4, "score": 0, "title": "Cohort description: the Northern Ireland Longitudinal Study (NILS)", "venue": "International journal of epidemiology", "year": 2012 }, { "abstract": "The development of near isogenic lines (NILs) is a very important tool for both genetic and physiological dissection of drought resistance in rice. Two pairs of NILs differing for grain yield under drought stress were isolated and characterized for yield, yield related traits, and several physiological traits in a range of contrasting environments. In replicated field trials both NIL pairs differed significantly for grain yield under drought stress but showed similar yield potential, phenology, and yield component traits under non stress conditions. A polymorphism analysis study with 491 SSRs revealed that both NIL pairs are at least 96% genetically similar. These NILs show that small genetic differences can cause large difference in grain yield under drought stress in rice. In both pairs the drought tolerant NILs showed a significantly higher assimilation rate at later stages both under stress and non stress conditions. They also had a higher transpiration rate under non stress condition. The most tolerant NIL (IR77298 14 1 2 B 10) had significantly higher transpiration rate and stomatal conductance in severe stress conditions. In one pair the tolerant NIL had constitutively deeper roots than the susceptible NIL. In the second pair, which had higher mean root length than the first pair, the tolerant NIL had more roots, greater root thickness, and greater root dry weight than the susceptible NIL. Deeper root length may allow tolerant NILs to extract more water at deeper soil layers. It is concluded that enhanced rooting depth is an important strategy for dehydration avoidance and rice adaptation to drought stress, but root architecture might not be the only mechanism causing the significant yield increase we observed in lowland drought stress environments. To further dissect the drought avoidance mechanisms in rice, analysis of root hydraulic properties may be necessary.", "author_names": [ "Ramaiah Venuprasad", "Somayanda M Impa", "R P Veeresh Gowda", "Gary N Atlin", "Rachid Serraj" ], "corpus_id": 86460312, "doc_id": "86460312", "n_citations": 45, "n_key_citations": 4, "score": 0, "title": "Rice near isogenic lines (NILs) contrasting for grain yield under lowland drought stress", "venue": "", "year": 2011 } ]

[ { "abstract": "Abstract We report the failure of copper through silicon via (TSV) under biased thermal stress. The time dependent dielectric breakdown (TDDB) of the oxide liner in the TSV was measured to detect the migration of copper from TSV to silicon. The breakdown of the oxide liner occurred by thermal cracking followed by fast drift of copper ions through the crack. For the TSV structure, there were an initial decrease in the leakage current and then the breakdown of oxide, which is different from the 3 stage TDDB behavior observed in the planar metal oxide semiconductor (MOS) structure. Micro cracks in the oxide liner at the top corner of TSV were observed after TDDB measurement, and the thermal cracking of the oxide was caused by the expansion of copper TSV at test condition. Finite element analysis showed the tensile stress of 670 MPa concentrated at the top corner of the TSV. The mechanism of TDDB in both TSV and planar MOS structures were also described comparatively.", "author_names": [ "Seung-ho Seo", "Joo-Sun Hwang", "Jun-Mo Yang", "Wook-Jung Hwang", "Jun Yeob Song", "Won-Jun Lee" ], "corpus_id": 135584449, "doc_id": "135584449", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Failure mechanism of copper through silicon vias under biased thermal stress", "venue": "", "year": 2012 }, { "abstract": "To gain a deep understanding of yeast cell response to heat stress, multiple laboratory strains have been intensively studied via genome wide expression analysis for the mechanistic dissection of classical heat shock response (HSR) However, robust industrial strains of Saccharomyces cerevisiae have hardly been explored in global analysis for elucidation of the mechanism of thermotolerant response (TR) during fermentation. Herein, we employed data independent acquisition and sequential window acquisition of all theoretical mass spectra based proteomic workflows to characterize proteome remodeling of an industrial strain, ScY01, responding to prolonged thermal stress or transient heat shock. By comparing the proteomic signatures of ScY01 in TR versus HSR as well as the HSR of the industrial strain versus a laboratory strain, our study revealed disparate response mechanisms of ScY01 during thermotolerant growth or under heat shock. In addition, through proteomics data mining for decoding transcription factor interaction networks followed by validation experiments, we uncovered the functions of two novel transcription factors, Mig1 and Srb2, in enhancing the thermotolerance of the industrial strain. This study has demonstrated that accurate and high throughput quantitative proteomics not only provides new insights into the molecular basis for complex microbial phenotypes but also pinpoints upstream regulators that can be targeted for improving the desired traits of industrial microorganisms.", "author_names": [ "Weidi Xiao", "Xiaoxiao Duan", "Yuping Lin", "Qichen Cao", "Shanshan Li", "Yufeng Guo", "Yuman Gan", "Xianni Qi", "Yue Zhou", "Lihai Guo", "Peibin Qin", "Qinhong Wang", "Wenqing Shui" ], "corpus_id": 4717199, "doc_id": "4717199", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Distinct Proteome Remodeling of Industrial Saccharomyces cerevisiae in Response to Prolonged Thermal Stress or Transient Heat Shock.", "venue": "Journal of proteome research", "year": 2018 }, { "abstract": "Abstract The Double Ceramic Layer Thermal Barrier Coating (DCL TBC) consists of a top ceramic layer (TC1) an inside ceramic layer (TC2) bond coat (BC) and alloy substrate. The top ceramic layer is made by new ceramic materials which has the lower thermal conductivity, such as LZ, LZ7C3, LMA etc. Although these materials have good high temperature performance and thermal insulation properties, their thermal expansion coefficients are very low which cause higher degree of mismatch with material properties of alloy substrate. The behavior of the stress buffer effect of the layer of TC2 is investigated aiming at the DCL TBC with the two ceramic layers as LZ7C3(TC1) and 8YSZ(TC2) A FE model of the DCL TBC is established and the stress of the TC1 during the thermal cycles is calculated. Results show that the layer of TC2 has the behaviors of stress buffer effect on reducing the stress of TC1 and reducing the influence of the TGO growth upon the stress of TC1. The inner mechanism of the stress buffer effect is investigated based on the influence of the thermal expansion coefficient r of the TC2 layer. Results show that the TC1 layer varies with the TC2 layer, having different thermal expansion coefficients; and the stress buffer effect is dominant, affected by the thermal expansion coefficients of the TC2 layer. The thermal expansion coefficient should be neither too large nor too low; if its values are too low or too large, the stress levels of TC1 are all high. The reasonable range of the thermal expansion coefficient is investigated. Aiming at the DCL TBC with the two ceramic layer thicknesses as 150 mm, the reasonable range of the thermal expansion coefficient of TC2 is from 10.35 degC 1 (x10 6) to 10.887 degC 1 (x10 6)", "author_names": [ "Meng Wei Han", "Jihua Huang", "Shu-Hsing Chen" ], "corpus_id": 136750114, "doc_id": "136750114", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Behavior and mechanism of the stress buffer effect of the inside ceramic layer to the top ceramic layer in a double ceramic layer thermal barrier coating", "venue": "", "year": 2014 }, { "abstract": "Using an IgG1 antibody as a model system, we have studied the mechanisms by which multidomain proteins aggregate at physiological pH when incubated at temperatures just below their lowest thermal transition. In this temperature interval, only minor changes to the protein conformation are observed. Light scattering consistently showed two coupled phases: an initial fast phase followed by several hours of exponential growth of the scattered intensity. This is the exact opposite of the lag time behavior typically observed in protein fibrillation. Dynamic light scattering showed the rapid formation of an aggregate species with a hydrodynamic radius of about 25 nm, which then increased in size throughout the experiment. Theoretical analysis of our light scattering data showed that the aggregate number density goes through a maximum in time providing compelling evidence for a coagulation mechanism in which aggregates fuse together. Both the analysis as well as size exclusion chromatography of incubated samples showed the actual increase in aggregate mass to be linear and reach saturation long before all molecules had been converted to aggregates. The CH2 domain is the only domain partly unfolded in the temperature interval studied, suggesting a pivotal role of this least stable domain in the aggregation process. Our results show that for multidomain proteins at temperatures below their thermal denaturation, transient unfolding of a single domain can prime the molecule for aggregation, and that the formation of large aggregates is driven by coagulation.", "author_names": [ "Christian Beyschau Andersen", "Mauro Manno", "Christian Rischel", "Matthias Thorolfsson", "Vincenzo Martorana" ], "corpus_id": 19739139, "doc_id": "19739139", "n_citations": 65, "n_key_citations": 1, "score": 0, "title": "Aggregation of a multidomain protein: A coagulation mechanism governs aggregation of a model IgG1 antibody under weak thermal stress", "venue": "Protein science a publication of the Protein Society", "year": 2010 }, { "abstract": "ABSTRACT Coral bleaching is intensifying with global climate change. Although the causes for these catastrophic events are well understood, the cellular mechanism that triggers bleaching is not well established. Our understanding of coral bleaching processes is hindered by the lack of robust methods for studying interactions between host and symbiont at the single cell level. Here, we exposed coral explants to acute thermal stress and measured oxidative stress, more specifically, reactive oxygen species (ROS) in individual symbiont cells. Furthermore, we measured concentrations of dimethylsulphoniopropionate (DMSP) and dimethylsulphoxide (DMSO) to elucidate the role of these compounds in coral antioxidant function. This work demonstrates the application of coral explants for investigating coral physiology and biochemistry under thermal stress and delivers a new approach to study host symbiont interactions at the microscale, allowing us to directly link intracellular ROS with DMSP and DMSO dynamics. Summary: We use coral explants to link intracellular ROS in vivo under thermal stress with dimethylated sulphur compounds (DMSP and DMSO) supporting the involvement of these compounds in oxidative stress regulation.", "author_names": [ "Stephanie G Gardner", "Jean-Baptiste Raina", "Peter J Ralph", "Katherina Petrou" ], "corpus_id": 1349173, "doc_id": "1349173", "n_citations": 22, "n_key_citations": 1, "score": 0, "title": "Reactive oxygen species (ROS) and dimethylated sulphur compounds in coral explants under acute thermal stress", "venue": "Journal of Experimental Biology", "year": 2017 }, { "abstract": "To obtain the inner damage mechanism of a new type of thermal stress precision cropping bar.A thermal stress coupling model of the bar with an annular V shaped notch in the course of cooling was established.The stress field in the inner of the bar was evaluated by means of ANSYS software.The numerical simulation results show that the axial tension stress gets maximum at 0.34 mm from the bottom of the tip of the V shaped notch on the bar cross section.As the maximal stress and its nearby stress exceed the ultimate yield strength of the material,an annular damage strip in the bar cross section of the V shaped notch and close to V shaped notch tip appears.At the same cycle cool water velocity,the damage strip increases and then decreases with the increase of width of adiabatic boundary,and reaches to the maximum when the width of adiabatic boundary is 2 mm.With the same width of adiabatic boundary,the damage strip increases with the increase of water velocity,and it changes feebly when the water velocity is greater than 5 m/s.The damage strip disappears when the water velocity is equal to 1 m/s.The cropping experimental results show that the cropping time,by heat stress prefabricating an ideal crack at V shaped notch bottom,is reduced by 15% compared with the simplex variable frequency vibration cropping method without the action of the heat stress,which validates the thermal stress behaviors.", "author_names": [ "Tang Yong" ], "corpus_id": 130532880, "doc_id": "130532880", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Inner Damage Mechanism of Metal Bar with Thermal Stress", "venue": "", "year": 2009 }, { "abstract": "Abstract The residual stress and failure mode of thermal barrier coating (TBC) containing metallic bond coat (BC) and ceramic top coat (TC) with and without thermally grown oxide (TGO) were predicted using a micromechanical based finite element method (FEM) Actual microstructures of the TBC taken by a scanning electron microscope (SEM) were utilized as the representative volume elements (RVEs) in the computational model. Failure mode of the representative volume was numerically simulated as thermal stress localization during thermal cycle. Computations were done on the representative volume to quantitatively assess the effects of thermal and mechanical properties of the TBC constituents as well as the presence of TGO on the macroscopic mechanical response of the TBC. Comparisons of computed results with experiments verified that, the computational method can successfully predict residual stress and crack initiation mode of the studied thermal barrier coatings. Moreover, based on the computed results, both shear and normal failure mode occur in the thermal barrier coating which is in good agreement with experimental findings.", "author_names": [ "N Nayebpashaee", "S H Seyedein", "Mohammad Reza Aboutalebi", "H Sarpoolaky", "S M M Hadavi" ], "corpus_id": 138467574, "doc_id": "138467574", "n_citations": 67, "n_key_citations": 0, "score": 0, "title": "Finite element simulation of residual stress and failure mechanism in plasma sprayed thermal barrier coatings using actual microstructure as the representative volume", "venue": "", "year": 2016 }, { "abstract": "ABSTRACT A change in temperature may be responsible for a variety of physiological stress responses in organisms, which are often associated with enhanced generation of reactive oxygen species (ROS) leading to oxidative damage. In the present study, the lipid peroxidation (LPO) levels of the oriental fruit fly, Bactrocera dorsalis (Hendel) were measured under thermal stress conditions of the relatively low 5, 2.5, 0, and 5 degC) or high (35, 37.5, and 40 degC) temperatures. Subsequently, the time related effect of thermal stress on activity of antioxidant enzymes including catalase (CAT) glutathione S transferases (GSTs) peroxidase (POX) superoxide dismutase (SOD) and total antioxidant capacity (T AOC) were systematically determined. The results showed that LPO levels increased significantly in a time dependent manner under thermal stress. The activities of CAT, GSTs, and SOD were significantly enhanced and likely provided a defense mechanism against oxidative damage due to the accumulation of ROS. POX and T AOC levels were not significantly modified. These results suggest that thermal stress induces oxidative stress, and antioxidant enzymes likely play an important role in reducing oxidative damage in B. dorsalis.", "author_names": [ "Fu-Xian Jia", "Wei Dou", "Fei Hu", "Jin-Jun Wang" ], "corpus_id": 30707906, "doc_id": "30707906", "n_citations": 52, "n_key_citations": 6, "score": 1, "title": "Effects of Thermal Stress on Lipid Peroxidation and Antioxidant Enzyme Activities of Oriental Fruit Fly, Bactrocera dorsalis (Diptera: Tephritidae)", "venue": "", "year": 2011 }, { "abstract": "Size exclusion chromatography with light scattering detection (SEC MALLS) was assessed as a means to characterize the type of bevacizumab aggregates that form under mechanical and thermal stress, quantitatively monitoring the aggregation kinetics. The analytical method was monitored and verified during routine use at two levels: (1) the \"pre study\" validation shows that the method is specific, linear, accurate, precise, robust and stability indicating; (2) the \"in study\" validation was verified by inserting quality control samples and the use of control charts, indicating that the analytical method is in statistical control and stable. The aggregation kinetics data were interpreted using a modified Lumry Eyring model, but the quality of the fit can be considered poor (R(2)>0.96) especially at higher temperatures. This indicates that the order of the reaction could not be reliably determined, suggesting a different degradation mechanism. The kinetic data set also fit the minimalistic Finke Watzky (F W) 2 step model, with an excellent quality of fit (R(2)>0.99) yielding the first quantitative rate constant for the steps of nucleation and growth in bevacizumab aggregation. The bevacizumab pharmaceutical preparation contains (initially) dimers, approximately 1.6% of bevacizumab total concentration, and the effect on aggregation kinetics of seeding was analyzed using the F W 2 step model assuming [B]00 (for the seeded case) The results suggested that the seeding had no impact on aggregation kinetics. Furthermore, the Arrhenius equation cannot be used to extrapolate the shelf life since no linear temperature dependence of the rate constant was found within the temperature range. Although the real time stability data provides the basis for determining the product shelf life, predictive methodologies such as Vogel Tammann Fulcher (VFT) or the Arrhenius approach can be misleading and result in overestimates of the product shelf life. However, they can be successfully applied to fixing the lower and upper limits of the aggregation rate, i.e. the best and worst case scenarios regarding the aggregation potential of the product. In conclusion, the present study evaluates the first application of the F W 2 step model to fitting and interpretation of experimental aggregation data for bevacizumab pharmaceutical preparations, using SEC MALLS in this context.", "author_names": [ "Alexis Oliva", "Matias Llabres", "Jose B Farina" ], "corpus_id": 37404379, "doc_id": "37404379", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Fitting bevacizumab aggregation kinetic data with the Finke Watzky two step model: Effect of thermal and mechanical stress.", "venue": "European journal of pharmaceutical sciences official journal of the European Federation for Pharmaceutical Sciences", "year": 2015 }, { "abstract": "Abstract The two dimensional (2D) graphene nanoplatelets (GNPs) were adopted to enhance the thermal conductivity of PBX. The results indicated that, the thermal conductivity of PBX was only slightly improved with very low GNP loading (0.05 wt% and 0.15 wt% However, a remarkable enhanced effect was observed at a relatively high GNP loading (0.5 wt% and 1 wt% The thermal conductivity of PBX had a nonlinear dependence on the GNPs loading. The nonlinear dependence of the thermal conductivity on GNPs content was fitted by an analytical model which incorporated all the effects. And the thermal conduction mechanism of GNPs based composite could change from series thermal structure to parallel thermal structure with the GNP loading increasing. Additionally, the calculated thermal shock resistance and thermal stress distribution of PBX was both enhanced with the GNP loading. Finally, the sensitivity of sensitive hexanitrohexaazaisowurtzitane (CL 20) based PBX composition could be improved by GNPs due to enhanced thermal conductivity.", "author_names": [ "Guansong He", "Zhijian Yang", "Xiaoyu Zhou", "Jianhu Zhang", "Liping Pan", "Shi-jun Liu" ], "corpus_id": 137788331, "doc_id": "137788331", "n_citations": 42, "n_key_citations": 1, "score": 0, "title": "Polymer bonded explosives (PBXs) with reduced thermal stress and sensitivity by thermal conductivity enhancement with graphene nanoplatelets", "venue": "", "year": 2016 } ]

[ { "abstract": "In this paper, a novel soft switching power factor correction (PFC) interleaved AC DC boost converter is proposed. In the proposed novel converter, all of the semiconductor devices operate with soft switching. The main switches turn on with zero voltage transition (ZVT) and turn off with zero current transition (ZCT) without any extra voltage or current stresses. Auxiliary switch turns on with zero current switching (ZCS) and turns off with zero voltage switching (ZVS) Besides, the main diodes turn on with zero voltage switching (ZVS) and turns off with ZCS without any extra voltage or current stresses. Owing to interleaved structure, the ripple of the input current and output voltage is reduced. So, power factor quality is significantly good. The output current and voltage are controlled in wide line and load range. The theoretical analysis of converter is clarified and the operating modes are given in detail. The simulation results of converter are obtained for 1.5 kW and 100 kHz. It is observed that the semiconductor devices operate with soft switching (SS) perfectly. Also, the novel proposed converter has 0.99 power factor with sinusoidal current shape.", "author_names": [ "Naim Suleyman Ting", "Yakup Sahin", "Ismail Aksoy" ], "corpus_id": 46454739, "doc_id": "46454739", "n_citations": 1, "n_key_citations": 0, "score": 1, "title": "A soft switching power factor correction interleaved AC DC boost converter", "venue": "2016 10th International Conference on Compatibility, Power Electronics and Power Engineering (CPE POWERENG)", "year": 2016 }, { "abstract": "This paper presents a single phase ac dc ac converter with high frequency isolation, which employs the interleaved technique. The proposed converter is suitable for power quality applications, such as dynamic voltage restorers, uninterruptable power supplies, and voltage regulators. The modeling of power flow is presented, focusing on the minimization of the transformer current. This analysis is improved by the introduction of the actuators type concept, which ensures reduced current through the transformer. Moreover, the effective longitudinal inductance of the series association of the boost inductor and two interphase transformers is determined. The soft switching regions are also obtained as well as their dependency on the phase shift angle. The proposed converter is compared with one indirect ac dc ac topology, which uses the dual active bridge converter as the isolation stage. Experimental results are obtained to show that the proposed converter is able to provide power factor correction, mitigate voltage sags, and regulate the output voltage.", "author_names": [ "Olympio Cipriano da Silva Filho", "Bruno R de Almeida", "Demercil de Souza Oliveira Junior", "Tobias Rafael Fernandes Neto" ], "corpus_id": 52299810, "doc_id": "52299810", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "High Frequency Isolated AC DC AC Interleaved Converter for Power Quality Applications", "venue": "IEEE Transactions on Industry Applications", "year": 2018 }, { "abstract": "This paper presents a single phase ac dc ac converter with high frequency isolation, which employs the interleaved technique. The proposed converter is suitable for power quality applications, such as dynamic voltage restorers, uninterruptable power supplies, and voltage regulators. The modeling of power flow is presented, focusing on the minimization of the transformer current. This analysis is improved by the introduction of the actuators type concept, which ensures reduced current through the transformer. Moreover, the effective longitudinal inductance of the series association of the boost inductor and two interphase transformers is determined. The soft switching regions are also obtained as well as their dependency on the phase shift angle. The proposed converter is compared with one indirect ac dc ac topology, which uses the dual active bridge converter as the isolation stage. Experimental results are obtained to show that the proposed converter is able to provide power factor correction, mitigate voltage sags, and regulate the output voltage.", "author_names": [ "Olympio C Silva Filho", "Bruno Ricardo de Almeida", "Demercil de Souza Oliveira Junior", "Tobias Rafael Fernandes Neto" ], "corpus_id": 115195210, "doc_id": "115195210", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "High Frequency Isolated AC DC AC Interleaved Converter for Power Quality Applications", "venue": "", "year": 2018 }, { "abstract": "This work presents the operation and design of a high power factor power supply. A good power factor is obtained using, as a preregulator circuit, an AC DC boost power converter interleaved using a nondissipative snubber and operating at a frequency of 100 kHz per cell. By using interleaved power converters, one can obtain an overall reduction of the boost inductor, together with reduced switching losses. A nondissipative snubber associated with the forward converter providing the soft commutation switching is used as the DC DC power converter. It also is presented. The output voltage is controlled by PWM with a constant frequency. The complete operating principles, theoretical analysis, relevant equations and simulation results are presented. Experimental results of a prototype rated at 500 watts, with an input AC voltage of 150 Vrms and, an output of 50 Vdc has been implemented in laboratory.", "author_names": [ "J A Correa Pinto", "A A Pereira", "Valdeir J Farias", "Luiz C de Freitas", "J B Jr Vieira" ], "corpus_id": 109876065, "doc_id": "109876065", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A high frequency switching power supply with power factor correction using a preregulator AC DC interleaved boost with soft commutation", "venue": "ISIE '97 Proceeding of the IEEE International Symposium on Industrial Electronics", "year": 1997 }, { "abstract": "This project presents a three phase unity power factor single stage ac dc converter based on an interleaved topology. High power factor and high conversion efficiency can be achieved by a simple single stage circuit with soft switching features. This converter achieves both power factor correction and output voltage regulation in a single stage of power conversion. Some of the main characteristics of the converter are low voltage stress in the main devices, lower total harmonic distortion (THD) when compared with the single switch boost rectifier, small number of components, simple control, and low cost. The proposed rectifier can produce input currents that do not have dead band regions with high PFC, operate with a continuous output current, and minimize the input electromagnetic interference filter size. This converter enjoys natural power factor correction with low line current harmonic distortion and symmetric high frequency voltage and current waveforms while ensuring zero voltage switching for all the switches for a wide variation in load and line voltage. The simulation results are carried proposed topology is evaluated through DC Motor and to analysis by using MATLAB/SIMULINK software simulation results are conferred.", "author_names": [ "Rose Swapna", "Rosaiah Mudigondala" ], "corpus_id": 59936194, "doc_id": "59936194", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Control of Three Phase Interleaved PFC AC DC Converter fed DC Motor", "venue": "", "year": 2016 }, { "abstract": "This paper proposes a novel single phase single stage ac dc converter with high frequency isolation and power factor correction. Unlike the two stage ac dc converters, the high frequency pulsating voltage is obtained directly from the power factor correction semistage and is applied directly to the dc dc semistage. The proposed topology is designed to be operated in the continuous conduction mode (CCM) and therefore, there is no need for additional input filter. In addition, the interleaving operation helps reducing the current stress and gets a better electro magnetic interference performance. Moreover, all of the power switches in the proposed topology can achieve soft switching commutation. Furthermore, the intermediate dc link capacitor is no longer directly connected to the dc dc stage and the capacitance can be reduced greatly; therefore, the bulk capacitor is replaced by a film capacitor. Frequency characteristics and time domain analysis of the LLC resonant tank is presented in this paper to analyze the characteristics of the proposed converter. Finally, a prototype that converts universal input voltage ranging from 110 to 220 V into 400 V dc output was built and tested to verify the analysis.", "author_names": [ "Guangdi Li", "Jin Xia", "Kun Wang", "Yan Deng", "Xiangning He", "Yousheng Wang" ], "corpus_id": 149977568, "doc_id": "149977568", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "A Single Stage Interleaved Resonant Bridgeless Boost Rectifier with High Frequency Isolation", "venue": "IEEE Journal of Emerging and Selected Topics in Power Electronics", "year": 2020 }, { "abstract": "Abstract: The aim of the project is to develop a high power factor and efficient AC DC converter suitable for charging batteries that are used in electric vehicles. The energy conversion during the battery charging is performed by an ac/dc converter. Boost converters are generally used to realize input PFC and ac/dc conversion. In high power applications, interleaving continuous current mode PFC boost stages are used. A novel, yet simple zero voltage switching (ZVS) interleaved boost power factor correction (PFC) ac/dc converter used to charge the traction battery of an electric vehicle from the utility mains is proposed here. The proposed converter implements soft switching through a simple passive auxiliary circuit placed in between the two phases of the interleaved boost converter. This auxiliary circuit provides reactive current during the transition times of the MOSFETs to charge and discharge the output capacitors of the MOSFETs. In addition, the control system effectively optimizes the amount of reactive current required to achieve ZVS for the power MOSFETs. This optimization is crucial in this application since the converter may work at very light loads for a long period of time. The proposed converter maintains ZVS for the universal input voltage, which includes a very wide range of duty ratios.", "author_names": [ "Kaviyadharshini Sivaraman", "Bhavani Vaidiyanathan" ], "corpus_id": 17442456, "doc_id": "17442456", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High Power Factor Interleaved Boost ACDC Converter with ZVS for Charging Battery Operated Vehicles", "venue": "", "year": 2013 }, { "abstract": "This paper proposes as a power factor correction pre regulator converter an AC DC interleaved boost flyback using a nondissipative snubber and operating at 100 kHz per cell. That is composed by switches working in ZCS and ZVS way, controlled by PWM. By using interleaved converters, an overall reduction of the boost inductor can be obtained, reducing switching losses without increasing current and voltage stresses. This topology has the advantages of interleaved flyback that eliminates an auxiliary source and an inductor in this configuration. The complete operating principles, theoretical analysis, relevant equations and simulation results are given to show the feasibility of the proposed power factor correction converter. Experimental results are presented in this work, with a power tested with the prototype rated at 2000 Watts.", "author_names": [ "Carlos Alberto Gallo", "J A Correa Pinto", "Luiz C de Freitas", "Valdeir J Farias", "J B Jr Vieira", "Ernane Antonio Alves Coelho" ], "corpus_id": 111200886, "doc_id": "111200886", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Soft switched PWM high frequency with PFC converter using boost flyback converter interleaved", "venue": "24th Annual International Telecommunications Energy Conference", "year": 2002 }, { "abstract": "This paper proposes a single stage light emitting diode (LED) driver with interleaving power factor correction (PFC) feature for street lighting applications. The presented circuit integrates an interleaved boost PFC converter with a half bridge type LLC resonant converter into a single stage power converter. The presented AC DC resonant converter uses interleaving methods to achieve input current shaping, and possesses soft switching functions on two active power switches to reduce their switching losses in order to increase the circuit efficiency. The proposed LED driver features low levels of input current ripple, reduced switching losses, high power factor, low total harmonics distortion (THD) of input current, and a reduced components count. Finally, a prototype driver is successfully implemented and tested to provide a 144W rated LED street lighting module with a 110V utility line input voltage. Experimental results demonstrate the feasibility of the proposed circuit.", "author_names": [ "Chun-An Cheng", "Hung-Liang Cheng", "Chien-Hsuan Chang", "Fu-Li Yang", "Tsung-Yuan Chung" ], "corpus_id": 24472801, "doc_id": "24472801", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "A single stage LED driver for street lighting applications with interleaving PFC feature", "venue": "2013 International Symposium on Next Generation Electronics", "year": 2013 }, { "abstract": "This paper introduces a new soft switching single phase power factor correction (PFC) boost converter with passive snubber. In the proposed converter, the main switch is turned on under zero current switching (ZCS) and turned off under zero voltage switching (ZVS) owing to the proposed passive snubber. Besides, the main diode is turned on under ZVS and turned off under ZCS. The proposed converter has features such as low cost, simple control, low number of element and high power density. Also, the output current and voltage are controlled by the proposed PFC converter in wide line and load range. The operating modes of the proposed converter are presented in detail. Also, the simulation results of converter are obtained for 1 kW and 100 kHz. It is observed that the new proposed converter has 0.99 power factor with sinusoidal current shape. So, power factor quality is fairly high.", "author_names": [ "Naim Suleyman Ting", "Nihan Altintas" ], "corpus_id": 20803136, "doc_id": "20803136", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A soft switching single phase power factor correction AC DC boost converter with passive snubber", "venue": "2017 4th International Conference on Electrical and Electronic Engineering (ICEEE)", "year": 2017 } ]

[ { "abstract": "Abstract A novel carbon allotrope, denoted P2/m C54, is proposed in this work. The structural properties, mechanical properties, mechanical and dynamical stability, relative formation enthalpy, anisotropy in Young's modulus and electronic properties for P2/m C54 are investigated in this work. First, P2/m C54 is found to remain mechanically and dynamically stable below 100 GPa, with a relative formation enthalpy that is 0.729 eV/atom less than that of T carbon. The bulk modulus, shear modulus and Young's modulus of P2/m C54 are calculated to be 345 GPa, 332 GPa and 754 GPa, respectively; the hardness of P2/m C54 is calculated to be 54.1 GPa and 70.4 GPa using Chen's model and Lyakhov and Oganov's model, respectively. All these calculations suggest that P2/m C54 is a potential superhard material. Furthermore, the band gap of P2/m C54 is determined to be 4.95 eV; in other words, P2/m C54 is an indirect band gap semiconductor material with a wide band gap at ambient pressure.", "author_names": [ "Xiaozhen Li", "Mengjiang Xing" ], "corpus_id": 214208096, "doc_id": "214208096", "n_citations": 27, "n_key_citations": 0, "score": 1, "title": "Prediction of a novel carbon allotrope from first principle calculations: A potential superhard material in monoclinic symmetry", "venue": "", "year": 2020 }, { "abstract": "A metastable sp3 bonded carbon allotrope, Penta C20, consisting entirely of carbon pentagons linked through bridge like bonds, was proposed and studied in this work for the first time. Its structure, stability, and electronic and mechanical properties were investigated based on first principles calculations. Penta C20 is thermodynamically and mechanically stable, with equilibrium total energy of 0.718 and 0.184 eV/atom lower than those of the synthesized T carbon and supercubane, respectively. Penta C20 can also maintain dynamic stability under a high pressure of 100 GPa. Ab initio molecular dynamics (AIMD) simulations indicates that this new carbon allotrope can maintain thermal stability at 800 K. Its Young's modulus exhibits mechanical anisotropy. The calculated ideal tensile and shear strengths confirmed that Penta C20 is a superhard material with a promising application prospect. Furthermore, Penta C20 is a direct band gap carbon based semiconducting material with band gap of 2.89 eV.", "author_names": [ "Weibin Zhang", "Changchun Chai", "Qingyang Fan", "YanXing Song", "Yintang Yang" ], "corpus_id": 216110039, "doc_id": "216110039", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Penta C20: A Superhard Direct Band Gap Carbon Allotrope Composed of Carbon Pentagon", "venue": "Materials", "year": 2020 }, { "abstract": "Abstract We establish a novel carbon phase in purely sp3 bonded networks with a 14 atom orthorhombic unit cell, termed C14 carbon, by swarm structural searches. This novel carbon phase is dynamically and mechanically stable under ambient conditions. The C14 carbon exhibits a high bulk modulus of 407 GPa and Vickers hardness of 84.3 GPa, which are comparble to those of diamond. Simulated X ray diffraction pattern is in satisfactory agreement with the previously unresolved diffraction peaks found in detonation soot samples. Interestingly, electronic band structure calculations reveal that the C14 carbon is a semiconductor with a direct band gap of around 4.60 eV. These results establish a novel carbon phase with outstanding mechanical and electronic properties and offer insights for further exploring other carbon allotropes.", "author_names": [ "Xigui Yang", "Chaofan Lv", "Shijie Liu", "Jinhao Zang", "Jinxu Qin", "Mingrun Du", "Dongwen Yang", "Xing Ru Li", "Bing-bing Liu", "Chongxin Shan" ], "corpus_id": 204290751, "doc_id": "204290751", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "Orthorhombic C14 carbon: A novel superhard sp3 carbon allotrope", "venue": "", "year": 2020 }, { "abstract": "Abstract Single phase high entropy monoborides (HEMBs) of the CrB prototype structure have been synthesized for the first time. Reactive spark plasma sintering of ball milled mixtures of elemental precursor powders produced bulk (V0.2Cr0.2Nb0.2Mo0.2Ta0.2)B, (V0.2Cr0.2Nb0.2Mo0.2W0.2)B, and (V0.2Cr0.2Nb0.2Ta0.2W0.2)B HEMB specimens of ~98.3 99.5% relative densities. Vickers hardness was measured to be ~22 26 GPa at an indentation load of 9.8 N and ~32 37 GPa at 0.98 N. In particular, the load dependent hardness of (V0.2Cr0.2Nb0.2Ta0.2W0.2)B is higher than those of ternary (Ta0.5W0.5)B (already considered as superhard) and hardest reported high entropy metal diborides, and on a par with the classical superhard boride WB4.", "author_names": [ "Mingde Qin", "Qizhang Yan", "Haoren Wang", "Chongze Hu", "Kenneth S Vecchio", "Jian Luo" ], "corpus_id": 220870950, "doc_id": "220870950", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "High entropy monoborides: Towards superhard materials", "venue": "", "year": 2020 }, { "abstract": "Abstract Materials with superhard and conductive properties are valuable and have great potential applications in multifunctional devices under extreme conditions. Here we propose two carbon polymorphs with superior superhard and conductive properties via first principle calculations. These two carbon phases, called Orth C10 and Orth C10' contain 10 carbon atoms buckled through sp2 sp3 hybridized bonds in an orthorhombic unit cell with Pmmm and Pmm2 symmetry, which are energetically more stable than fullerene C60 at 0 GPa, and more favorable than graphite at the pressure above 34.4 and 45.4 GPa, respectively. More importantly, their Vickers hardness are as high as 62.2 and 59.9 GPa, respectively, close to the hardness of cubic boron nitride, the second hardest material. Specially, Orth C10' owns ultra high axial incompressibility even beyond that of diamond at a pressure above 40 GPa. Furthermore, both Orth C10 and Orth C10' are metallic, which is rare in superhard carbon polymorphs. These outstanding natures make Orth C10 and Orth C10' potential materials for electronic devices and mechanical tools.", "author_names": [ "Lingyu Liu", "Meng Hu", "Zhisheng Zhao", "Yilong Pan", "Huafeng Dong" ], "corpus_id": 210232207, "doc_id": "210232207", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Superhard conductive orthorhombic carbon polymorphs", "venue": "", "year": 2020 }, { "abstract": "", "author_names": [ "Heng Liu", "Qingyang Fan", "Fang Yang", "Xinhai Yu", "Wei Zhang", "Sining Yun" ], "corpus_id": 225180090, "doc_id": "225180090", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "tP40 carbon: A novel superhard carbon allotrope", "venue": "", "year": 2020 }, { "abstract": "The computational prediction of superhard materials would enable the in silico design of compounds that could be used in a wide variety of technological applications. Herein, good agreement was found between experimental Vickers hardnesses, Hv, of a wide range of materials and those calculated by three macroscopic hardness models that employ the shear and/or bulk moduli obtained from: (i) first principles via AFLOW AEL (AFLOW Automatic Elastic Library) and (ii) a machine learning (ML) model trained on materials within the AFLOW repository. Because $H_{\\mathrm{v}\\mathrm{ML}$HvML values can be quickly estimated, they can be used in conjunction with an evolutionary search to predict stable, superhard materials. This methodology is implemented in the XtalOpt evolutionary algorithm. Each crystal is minimized to the nearest local minimum, and its Vickers hardness is computed via a linear relationship with the shear modulus discovered by Teter. Both the energy/enthalpy and $H_{\\mathrm{v,Teter}\\mathrm{ML}$Hv,TeterML are employed to determine a structure's fitness. This implementation is applied towards the carbon system, and 43 new superhard phases are found. A topological analysis reveals that phases estimated to be slightly harder than diamond contain a substantial fraction of diamond and/or lonsdaleite.", "author_names": [ "Patrick Avery", "Xiaoyu Wang", "Corey Oses", "Eric Gossett", "Davide M Proserpio", "Cormac Toher", "Stefano Curtarolo", "Eva Zurek" ], "corpus_id": 189898460, "doc_id": "189898460", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Predicting superhard materials via a machine learning informed evolutionary structure search", "venue": "npj Computational Materials", "year": 2019 }, { "abstract": "Two novel superhard 3D sp3 hybridized carbon allotropes (Cmmm C32 and P6/mmm C54) are proposed in this work through first principles calculations. Both Cmmm C32 and P6/mmm C54 have a honeycomb structure. P6/mmm C54 shows a wide direct bandgap (3.564 eV) while Cmmm C32 shows an ultrawide indirect bandgap (5.051 eV) as determined using the HSE06 hybrid functional. The hardnesses of Cmmm C32 and P6/mmm C54 are 83.72 and 54.01 GPa, respectively, and their calculated ideal strengths further confirm their superhardness characteristics. P6/mmm C54 is isotropic in the (001) plane. The minimum thermal conductivities of Cmmm C32 and P6/mmm C54 are larger than those of diamond C, illustrating that Cmmm C32 and P6/mmm C54 are potential semiconductor device materials.Two novel superhard 3D sp3 hybridized carbon allotropes (Cmmm C32 and P6/mmm C54) are proposed in this work through first principles calculations. Both Cmmm C32 and P6/mmm C54 have a honeycomb structure. P6/mmm C54 shows a wide direct bandgap (3.564 eV) while Cmmm C32 shows an ultrawide indirect bandgap (5.051 eV) as determined using the HSE06 hybrid functional. The hardnesses of Cmmm C32 and P6/mmm C54 are 83.72 and 54.01 GPa, respectively, and their calculated ideal strengths further confirm their superhardness characteristics. P6/mmm C54 is isotropic in the (001) plane. The minimum thermal conductivities of Cmmm C32 and P6/mmm C54 are larger than those of diamond C, illustrating that Cmmm C32 and P6/mmm C54 are potential semiconductor device materials.", "author_names": [ "Wei Zhang", "Changchun Chai", "Qingyang Fan", "YanXing Song", "Yintang Yang" ], "corpus_id": 209936399, "doc_id": "209936399", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Two novel superhard carbon allotropes with honeycomb structures", "venue": "Journal of Applied Physics", "year": 2019 }, { "abstract": "Superhard materials are of great interest in various practical applications, and an increasing number of research efforts are focused on their development. In this article, we demonstrate that machine learning can be successfully applied to searching for such materials. We construct a machine learning model using neural networks on graphs together with a recently developed physical model of hardness and fracture toughness. The model is trained using available elastic data from the Materials Project database and has good accuracy for predictions. We use this model to screen all crystal structures in the database and systematize all the promising hard or superhard materials, and find that diamond (and its polytypes) are the hardest materials in the database. Our results can be further used for the investigation of interesting materials using more accurate ab initio calculations and/or experiments.", "author_names": [ "Efim A Mazhnik", "Artem R Oganov" ], "corpus_id": 225474947, "doc_id": "225474947", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Application of machine learning methods for predicting new superhard materials", "venue": "", "year": 2020 }, { "abstract": "Abstract A fabrication route based on aqueous colloidal processing plus transient liquid phase assisted spark plasma sintering (SPS) with Ti Al additives is described for the environmentally friendly obtention of superhard B4C composites reinforced with reduced graphene oxide (rGO) having orthotropic and isotropic microstructures. It is shown that the former, which have coarse rGO platelets preferentially aligned perpendicular to the SPS pressing direction, can be prepared from mixtures of B4C and Ti Al particles with a source of thick, large rGO nanoplatelets by imposing smooth co dispersion conditions to avoid platelet re exfoliation and fragmentation. The latter, which have fine rGO platelets randomly oriented, can be fabricated from mixtures of B4C and Ti Al particles with a source of thin, small rGO nanoplatelets by applying intensive sonication to promote platelet re exfoliation and fragmentation during co dispersion. Finally, it is shown that these orthotropic and isotropic B4C/rGO composites are equally superhard, and that, as expected, their microstructures interact differently with the cracks. Finally, this processing route is simple, and easily adaptable/extensible to make other ceramic/rGO composites with orthotropic and isotropic microstructures.", "author_names": [ "Cristina Ojalvo", "Rodrigo Moreno", "Fernando Guiberteau", "Angel L Ortiz" ], "corpus_id": 212792612, "doc_id": "212792612", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Processing of orthotropic and isotropic superhard B4C composites reinforced with reduced graphene oxide", "venue": "", "year": 2020 } ]

[ { "abstract": "We have calculated the longitudinal acoustic phonon limited electron mobility of 14 two dimensional semiconductors with composition of MX2, where M Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, Se and Te. We treated the scattering matrix by the deformation potential approximation. We found that out of 14 compounds, MoTe2, HfSe2 and ZrSe2 are promising regarding to their possible high mobility and finite band gap. The phonon limited mobility can be above 2,500 cm2*V 1*s 1 at room temperature.", "author_names": [ "Wenxu Zhang", "Zhishuo Huang", "Wanli Zhang", "Yanrong Li" ], "corpus_id": 73665487, "doc_id": "73665487", "n_citations": 389, "n_key_citations": 2, "score": 1, "title": "Two dimensional semiconductors with possible high room temperature mobility", "venue": "Nano Research", "year": 2014 }, { "abstract": "We calculated the electron mobility of 14 two dimensional semiconductors with composition of MX2, where M Mo, W, Sn, Hf, Zr and Pt) is the transition metal, and X is S, Se and Te. We treated the scattering matrix by deformation potential approximation. Long wave longitudinal acoustical and optical phonon scatterings are included. Piezoelectric scattering in the compounds without inversion symmetry is also taken into account. We found that out of the 14 compounds, WSe2, PtS2 and PtSe2, are promising regarding to the possible high electron mobility and finite band gap. The phonon limited mobility in PtSe2 reaches about 3000 cm 2V 1s 1 at room temperature which is the highest among the compounds. The bandgap under the local density approximation is 1.25 eV. Our results can be a guide for experiments to search for better two dimensional materials for future semiconductor devices. a email to: [email protected] 1 ar X iv :1 50 5. 05 69 8v 1 co nd m at .m tr lsc i] 2 1 M ay 2 01 5", "author_names": [ "Zhishuo Huang", "Wenxu Zhang", "Wanli Zhang", "Yanrong Li" ], "corpus_id": 119201530, "doc_id": "119201530", "n_citations": 65, "n_key_citations": 0, "score": 0, "title": "Screening for Two dimensional MX$_2$ semiconductors with possible high room temperature mobility", "venue": "", "year": 2015 }, { "abstract": "Neither of the two typical two dimensional materials, graphene and single layer MoS2, are good enough for developing semiconductor logical devices. We calculated the electron mobility of 14 two dimensional semiconductors with composition of MX2, where M =Mo, W, Sn, Hf, Zr and Pt) are transition metals, and Xs are S, Se and Te. We approximated the electron phonon scattering matrix by deformation potentials, within which long wave longitudinal acoustical and optical phonon scatterings were included. Piezoelectric scattering in the compounds without inversion symmetry is also taken into account. We found that out of the 14 compounds, WS2, PtS2 and PtSe2 are promising for logical devices regarding the possible high electron mobility and finite band gap. Especially, the phonon limited electron mobility in PtSe2 reaches about 4000 cm2*V 1*s 1 at room temperature, which is the highest among the compounds with an indirect bandgap of about 1.25 eV under the local density approximation. Our results can be the first guide for experiments to synthesize better two dimensional materials for future semiconductor devices.", "author_names": [ "Zhishuo Huang", "Wenxu Zhang", "Wanli Zhang" ], "corpus_id": 15546968, "doc_id": "15546968", "n_citations": 55, "n_key_citations": 1, "score": 0, "title": "Computational Search for Two Dimensional MX2 Semiconductors with Possible High Electron Mobility at Room Temperature", "venue": "Materials", "year": 2016 }, { "abstract": "A possible failure mechanism of n channel MOSFETs exposed to ionizing radiation are leakage currents between source and drain. This leakage begins to occur at relatively low radiation doses, and can seriously degrade the performance of an otherwise hardened CMOS device. In the present paper, we demonstrate by the observation of quantum oscillations in the magnetoresistance that by room temperature irradiation with high energy electrons an inversion layer is generated under the field oxide, which gives rise to leakage currents. Magnetoresistance oscillations may be observed, if in a degenerate electron gas the carrier mobility is sufficiently high to allow quantization of the electron movement in a magnetic field and the thermal energy is much smaller than the cyclotron energy. This oscillatory behaviour of the electrical resistance as a function of a magnetic field the Shubnikov de Haas effect is a valuable tool to investigate the electronic parameters of bulk semiconductors and surface channels. Such experiments not only give firm evidence about the existence of a bypass inversion layer, but also yield information about the carrier density in the radiation induced channel. It turns out that the electrons behave like a two dimensional free electron gas the density of which is independent of the gate voltage. Moreover, the experiments give knowledge about the influence of trapped charges, caused by the irradiation at the interface.", "author_names": [ "M Roos", "Gottfried Landwehr" ], "corpus_id": 21936627, "doc_id": "21936627", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Shubnikov De Haas Oscillations Caused by a Two Dimensional Leakage Channel on Silicon Mosfets Induced by Electron Irradiation", "venue": "IEEE Transactions on Nuclear Science", "year": 1978 }, { "abstract": "Abstract Recently, Bi2O2Se is discovered as a promising two dimensional (2D) semiconductor for next generation electronics because of its stability in air, high Hall mobility and on/off ratio at room temperature. Using first principles calculations, we predict half metallicity in Mn doped monolayer Bi2O2Se. The magnetism enhancement from 4.0 to 6.0 uB and half metal to magnetic semiconductor transition of monolayer Bi2O2Se are realizable by applying biaxial tensile strain. The symmetry reduction at the elastic plastic transition is the key factor in controlling the magnetic coupling order between the Mn and the neighboring Se atoms. The results imply a possible way to achieve two dimensional magnetic semiconductors that have great potential applications in spintronic devices.", "author_names": [ "Y J Zhu", "Xiaogang Wei", "Yan Ming Song", "Qi Wei", "Changqing Lin", "Nannan Han", "Wenbo Mi", "Yingchun Cheng", "Wei Huang" ], "corpus_id": 126523496, "doc_id": "126523496", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Half metal to magnetic semiconductor transition in Mn doped monolayer Bi2O2Se tuned by strain", "venue": "Journal of Magnetism and Magnetic Materials", "year": 2019 }, { "abstract": "In this paper, we report high performance monolayer thin film transistors (TFTs) based on a variety of two dimensional layered semiconductors such as MoS2, WS2, and MoSe2 which were obtained from their corresponding bulk counterparts via an anomalous but high yield and low cost electrochemical corrosion process, also referred to as electro ablation (EA) at room temperature. These monolayer TFTs demonstrated current ON OFF ratios in excess of 107 along with ON currents of 120 mA/mm for MoS2, 40 mA/mm for WS2, and 40 mA/mm for MoSe2 which clearly outperform the existing TFT technologies. We found that these monolayers have larger Schottky barriers for electron injection compared to their multilayer counterparts, which is partially compensated by their superior electrostatics and ultra thin tunnel barriers. We observed an Anderson type semiconductor to metal transition in these monolayers and also discussed possible scattering mechanisms that manifest in the temperature dependence of the electron mobility. Finally, our study suggests superior chemical stability and electronic integrity of monolayers even after being exposed to extreme electro oxidation and corrosion processes which is promising for the implementation of such TFTs in harsh environment sensing. Overall, the EA process proves to be a facile synthesis route offering higher monolayer yields than mechanical exfoliation and lower cost and complexity than chemical vapor deposition methods.", "author_names": [ "Daniel S Schulman", "Amritanand Sebastian", "Drew Buzzell", "Yu-ting Huang", "Andrew J Arnold", "Saptarshi Das" ], "corpus_id": 206472299, "doc_id": "206472299", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "Facile Electrochemical Synthesis of 2D Monolayers for High Performance Thin Film Transistors.", "venue": "ACS applied materials interfaces", "year": 2017 }, { "abstract": "Two dimensional (2D) materials have attracted wide attention due to their exotic properties. In particular, the lack of dangling bonds makes it possible to build highly lattice mismatched heterostructures composed of 2D materials and conventional semiconductors. Here, we report that by simply stacking a chemical vapor deposition grown monolayer WS2 film onto the surface of a room temperature sputtered ZnO film, significant enhanced ultra violet (UV) photoresponse can be achieved. In this heterostructure of ZnO WS2, the ZnO film acts as a light harvesting layer while the WS2 monolayer functions as a carrier transport layer which facilitates the photocarrier transport and reduces its recombination. Such a mechanism was confirmed by the observation of further photoresponsivity improvement of the ZnO WS2 heterostructure under vacuum which removes the surface absorbates and thereby increases the carrier mobility of WS2. The strategy presented here can be applied to other wide band gap semiconductors, shedding light on high sensitivity and flexible UV photodetectors based on van der Waals heterostructures.", "author_names": [ "Changyong Lan", "Chun Li", "Shuaihao Wang", "Yi Yin", "Huayang Guo", "Nishuang Liu", "Yong Liu" ], "corpus_id": 100034733, "doc_id": "100034733", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "ZnO WS2 heterostructures for enhanced ultra violet photodetectors", "venue": "", "year": 2016 }, { "abstract": "The recent discovery of graphene (Novoselov et al. 2004) a single atomic sheet of graphite, has ignited intense research activities to explore the electronic properties of this novel twodimensional (2D) electronic system. Charge transport in graphene differs from that in conventional 2D electronic systems as a consequence of the conical energy dispersion relation near the charge neutrality (Dirac) point in the electronic band structure (Zhang et al. 2005) Field effect mobility as high as 15 000 cm2/V.s and a Fermi velocity of ~108 cm/s have been demonstrated at room temperature (Geim Novoselov 2007) These properties make graphene a possible candidate for electronic devices in the future. The major benefit of graphene frequently quoted is superior electron/hole mobility compared to other semiconductors, but as Fig. 1 shows, this is not experimentally the case yet when compared to narrow bandgap III V semiconductors for comparable carrier densities. In addition, the lack of a bandgap limits the usage of two dimensional graphene for digital switching, where high on/off ratios are necessary. However, several potential advantages may be listed: the perfect 2D confinement of carriers, electron/hole symmetry originating from a conical bandstructure, and the possibility of opening bandgaps lithographically by fabricating graphene nanoribbons (GNRs) In Section 2, high field characteristics of 2D exfoliated graphene are reported on both short channel and longchannel back gated field effect transistors (FETs) We will elaborate on the problem of metal contact formation and high field transport of 2D graphene. The comparison of fabricated devices based on exfoliated, epitaxial and chemical vapour deposited (CVD) graphene will follow. The large area graphene opens the possibility to make 2D graphene devices for RF/analog amplification (Lin et al. 2010) Superior frequency performance of such devices makes it a promising application of 2D graphene FETs. The real advantage of graphene, however, can be highlighted from a novel proposed device architecture that is yet to be demonstrated (Zhang et al. 2008) If GNRs are made by lithographic patterning, and are either chemically or electrostatically doped into GNR p n junctions, then the planar form yields to a tunnelling field effect transistor (TFET) Towards the realization of the GNR TFET we designed a single but tuneable junction structure to demonstrate the operational principle. We discuss these GNR p n junction transistors in Section 3 along with the developed analytical and device models used to explain the measured transistor characteristics.", "author_names": [ "Kristof Tahy", "Tian Fang", "Pei Zhao", "Aniruddha Konar", "Chuanxin Lian", "Michelle M Kelly", "Debdeep Jena" ], "corpus_id": 30360561, "doc_id": "30360561", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "20 Graphene Transistors", "venue": "", "year": 2012 }, { "abstract": "To obtain room temperature ferromagnetic semiconductors is one of big challenges in science, and also premises essentially to realize room temperature quantum anomalous Hall effect (QAHE) both of which are quite expected for a long time. Here we report that, based on first principles calculations, PdBr3, PtBr3, PdI3 and PtI3 monolayers are ferromagnetic semiconductors with possible high temperature QAHE. Monte Carlo simulations give Curie temperatures 350 K and 375 K for PdBr3 and PtBr3 monolayers, respectively. These two dimensional (2D) materials are Chern insulators. The band gaps of PdBr3 and PtBr3 are 58.7 meV and 28.1 meV with GGA and 100.8 meV and 45 meV with HSE06, respectively, quite well in favor of observing room temperature QAHE. The large band gaps were unveiled from multi orbital electron correlations. By carefully checking the stability, PdBr3, PtBr3, and PtI3 monolayers are all predicted to be feasible in experiment. The present work sheds new light on developing promising spintronic devices by using the room temperature ferromagnetic semiconductors, and dissipationless devices by applying room temperature QAHE.", "author_names": [ "Jing-Yang You", "Zhen Zhang", "Bo Gu", "Gang Su" ], "corpus_id": 174787311, "doc_id": "174787311", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Two Dimensional Room Temperature Ferromagnetic Semiconductors with Quantum Anomalous Hall Effect", "venue": "Physical Review Applied", "year": 2019 }, { "abstract": "Atomically thin (two dimensional, 2D) semiconductors have shown great potential as the fundamental building blocks for next generation electronics. However, all the 2D semiconductors that have been experimentally made so far have room temperature electron mobility lower than that of bulk silicon, which is not understood. Here, by using first principles calculations and reformulating the transport equations to isolate and quantify contributions of different mobility determining factors, we show that the universally low mobility of 2D semiconductors originates from the high \"density of scatterings,\" which is intrinsic to the 2D material with a parabolic electron band. The density of scatterings characterizes the density of phonons that can interact with the electrons and can be fully determined from the electron and phonon band structures without knowledge of electron phonon coupling strength. Our work reveals the underlying physics limiting the electron mobility of 2D semiconductors and offers a descriptor to quickly assess the mobility.", "author_names": [ "Long Cheng", "Chenmu Zhang", "Yuanyue Liu" ], "corpus_id": 225062138, "doc_id": "225062138", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Why Two Dimensional Semiconductors Generally Have Low Electron Mobility.", "venue": "Physical review letters", "year": 2020 } ]

[ { "abstract": "Effective theoretical models are needed to predict the physical properties of materials. Here we discuss the electronic structure of rhenium carbonitride (ReCN) in terms of tight binding. The extended Huckel tight binding (EHTB) formalism was employed to calculate the band structure, density of states (DOS) and investigate the chemical bonding properties as well as the crystal field splitting (CFS) of d orbitals in the Re atom. Two ReCN structures were studied, characterized by space groups P63mc and P3m1, respectively. The calculated energy bands and DOS depict semiconductor properties for both structures, seeing an indirect band gap of 0.62 eV in P63mc (M K) while a direct band gap of 0.49 eV is seen in P3m1 at (H) Mulliken population and CFS analysis were done to gain insight into the filling of 5d orbitals in ReCN, crystallographical differences between the two crystal structures and their physical implications. The five fold degenerate energy levels in both the P63mc and P3m1 structures are broken by a tetragonal crystal electric field. The P63mc structure undergoes Peierls distortion, resulting in a loss of symmetry. The EHTB method is an effective tool to approximate the physical and chemical properties of novel materials such as ReCN at a low computational cost and in terms of a simple quantum mechanical framework, understood by the broader community. The EHTB model for ReCN will serve as a benchmark and starting point for future studies on the compound within similar contexts.", "author_names": [ "Etienne Palos", "Jose I Paez", "Armando Reyes-Serrato", "Donald H Galvan" ], "corpus_id": 125463194, "doc_id": "125463194", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Electronic structure calculations for rhenium carbonitride: an extended Huckel tight binding study", "venue": "", "year": 2018 }, { "abstract": "Abstract Electronic structures of nine cubic perovskite type oxides ABO3's including SrTiO3, SrZrO3, SrHfO3, BaTiO3, BaZrO3, BaHfO3, PbTiO3, PbZrO3 and PbHfO3 were calculated using a band theory based on the self consistent charge extended Huckel tight binding (SCC XHTB) method incorporating the relativistic effects except for the spin orbit interaction in order to examine how the electronic structure changes due to the substitution of the A or B site atom. Moreover, calculations were also made for the tetragonal PbTiO3 to study the electronic structural changes due to the structural change from the cubic phase to the tetragonal one. It is shown that the upper valence band of all the ABO3's considered in the present paper consists of the 2p orbital of oxygen mixed with the d valence electrons of the B atom. The shape remains nearly the same in spite of the A or B site substitution. For the conduction band, it is shown that the bottom of which is made up from the ndt 2g band of the B atom for SrTiO3, SrZrO.", "author_names": [ "Michihide Kitamura", "Hayden Chen" ], "corpus_id": 122338567, "doc_id": "122338567", "n_citations": 20, "n_key_citations": 0, "score": 0, "title": "Electronic structure calculations of perovskite type oxides using the self consistent charge extended Huckel tight binding method", "venue": "", "year": 1998 }, { "abstract": "To gain insight into the electronic properties of MoSe2 (molybdenum selenide, also known as drysdallite) electronic structure calculations, total and projected density of states, crystal orbital overlap population and Mulliken population analysis were performed. The calculated energy bands depict a semiconductor behavior with a direct gap (at K) of 0.91 eV and an indirect gap (from G to K) of 3.6 eV, respectively. Total and projected density of states provided information about the contribution from each orbital of each atom to the total density of states. Moreover, the bonding strength between some atoms within the unit cell was obtained. Mulliken population analysis corroborates the electron filling of the Mo dz2 orbitals in agreement with another experimental and theoretical results.", "author_names": [ "Donald H Galvan" ], "corpus_id": 122196158, "doc_id": "122196158", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "ELECTRONIC STRUCTURE CALCULATIONS FOR MoSe2 USING EXTENDED HUCKEL TIGHT BINDING METHOD", "venue": "", "year": 2004 }, { "abstract": "A transferable tight binding parametrization procedure for extended Huckel approximation is proposed, with the charge self consistent scheme, that could be applied to the quantum molecular dynamics (MD) simulation for long time dynamics of large scale systems. In this procedure, either a target molecule is divided into small molecules or another realistic set of small molecules characterizing chemical bonds in the complicated target molecule is adopted. Then, the parameters for these small molecules are adjusted and compared with reference results of energy levels and wave functions by, for example, density functional theory. Upon application to the large target molecule, these parameters are then readjusted directly in the target molecule. An example is demonstrated with MD simulation applied to the ionic liquid molecule N methyl N propylpiperidinium bis trifluoromethanesulfonyl imide (PP13 TFSI) The origin and stability of HOMO LUMO gap are discussed.", "author_names": [ "Shinya Nishino", "Takeo Fujiwara" ], "corpus_id": 42227752, "doc_id": "42227752", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Parametrization scheme with accuracy and transferability for tight binding electronic structure calculations with extended Huckel approximation and molecular dynamics simulations", "venue": "Journal of Molecular Modeling", "year": 2013 }, { "abstract": "Abstract The spin polarized self consistent charge extended Huckel tight binding (SP SCC XHTB) method has been developed by authors to study the electronic structures of rutile type transition metal dioxides, MO2, with both the nonmagnetic and magnetic phases. This method has been used to successfully predict the electronic structures of nonmagnetic (n) MO2's with M =Ti, V, Nb, Ta, Cr and ferromagnetic (f) CrO2, but is inadequate to predict the value of the energy gap of a semiconductive n MnO2. The SP SCC XHTB band structure calculation, which includes all the relativistic effects in a first principal manner, has only one empirical parameter on the evaluation of the matrix elements of the non relativistic Hamiltonian H0. In this paper, the SP SCC XHTB method is improved so as to evaluate the matrix elements of the H0 in a more appropriate manner. The band structure calculations are carried out for the n MO2's with M =Ti, V, Nb, Ta, Cr and Mn, the f CrO2 and the af MnO2. With the improvement it is shown that the SP SCC IXHTB band structure calculations give reasonable results for the electronic structures of all the MO2's considered in the present paper.", "author_names": [ "Michihide Kitamura", "Kanryu Inoue", "Haydn H D Chen" ], "corpus_id": 96680001, "doc_id": "96680001", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Improvement of the spin polarized self consistent charge extended Huckel tight binding method", "venue": "", "year": 2000 }, { "abstract": "The extended Huckel (eH) tight binding method has historically been prized for its computational ease and intuitive chemical clarity. However, its lack of quantitative predictiveness has prevented the eH method from being used as a tool for rapidly screening materials for desired electronic properties. In this work, we demonstrate that when eH input parameters are calibrated using density functional theory (DFT) calculations of carefully chosen sets of simple crystals, the eH parameters retain most of their quantitative accuracy when transferred to more complex, structurally related phases. Using solar energy relevant semiconductors and insulators in the Sr Ti O family as a case study, we show that calibrated eH parameters can match the features of DFT band structures within about two tenths of an eV, at a tiny fraction of the computational cost of DFT.", "author_names": [ "Linda Grabill", "Robert F Berger" ], "corpus_id": 49671161, "doc_id": "49671161", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Calibrating the Extended Huckel Method to Quantitatively Screen the Electronic Properties of Materials", "venue": "Scientific Reports", "year": 2018 }, { "abstract": "In this work, we present a theoretical study of the electronic properties of group IV element nanosheets, namely graphene, silicene, germanene and the corresponding hydrogenated structures for the two latter, silicane and germanane. We compare the results of two different calculation methods, Density Functional Theory (DFT) and Extended Huckel Theory (EHT) for both pristine sheets and sheets of silicene and germanene with a single atom vacancy. We show that EHT offers a remarkably reliable description of the electronic structure of these materials for all cases, thus offering an affordable way for studying large systems for which DFT calculations would be expensive and lengthy.", "author_names": [ "Adriano S Martins", "Marcos Verissimo-Alves" ], "corpus_id": 26611737, "doc_id": "26611737", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Group IV nanosheets with vacancies: a tight binding extended Huckel study.", "venue": "Journal of physics. Condensed matter an Institute of Physics journal", "year": 2014 }, { "abstract": "In this work, we performed tight binding calculations of the electronic structure of III V semiconductors compounds and their alloys based on the Extended Huckel Theory (EHT) In particular, this paper is focused on the dependency between band gap and the applied pressure and also the alloy composition.", "author_names": [ "Ingrid A Ribeiro", "Fabio J Ribeiro", "Adriano S Martins" ], "corpus_id": 118453333, "doc_id": "118453333", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "An extended Huckel study of the electronic properties of III V compounds and their alloys", "venue": "", "year": 2014 }, { "abstract": "Abstract Band theory based on the spin polarized self consistent charge extended Huckel tight binding (SP SCC XHTB) method, which includes all the relativistic effects and the spin polarized self consistent field (SP SCF) atomic structure calculation based on the Hartree Fock Slater method, has been applied to the electronic structure calculations of tetragonal rutile type MO2s, such as nonmagnetic (n) TiO2, VO2, NbO2, TaO2, CrO2, MnO2, ferromagnetic (f) CrO2 and antiferromagnetic (af) MnO2. It is shown that the calculations are consistent with the experimental observations for all systems except the case of MnO2. It is demonstrated that the semiconductive nature of MnO2 can be explained by adding an assumption that three electrons in the Mn t2g orbital are localized in the crystal into the SP SCC XHTB band structure calculation.", "author_names": [ "Michihide Kitamura", "Kanryu Inoue", "Haydn H D Chen" ], "corpus_id": 97423008, "doc_id": "97423008", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Electronic structures of transition metal dioxides studied by the spin polarized self consistent charge extended Huckel tight binding method", "venue": "", "year": 1998 }, { "abstract": "We perform extended calculations of composed carbon structures where carbon acquires its sp or sp hybrid character. Based on an existing implementation of a tight binding (TB) model for carbon, we implement the calculation of the forces using the Hellmann Feynman theorem. The forces make it possible to use fast minimization algorithms to relax carbon nanostructures composed of up to several hundred atoms. We focus our investigation on carbynes (sp character) inserted in a nanohole inside a graphene sheet (sp character) and on carbon nanotubes mainly (sp character) After relaxation we compute the electronic structure, in particular we evaluated the band gaps for semiconducting nanotubes. The results are compared to DFT calculation and experimental observations. Finally, taking advantage of the forces, we perform molecular dynamics simulations of carbynes in graphene at high temperature, to investigate the stability of such a system. Advisor: Dr. Nicola Manini Co Advisor: Prof. Giovanni Onida", "author_names": [ "Nicola Manini", "Giovanni Onida", "Nicola Ferri" ], "corpus_id": 29348759, "doc_id": "29348759", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Universita degli Studi di Milano Facolta di Scienze Matematiche Fisiche e Naturali Laurea Triennale in Fisica Structural and electronic properties of carbon nanostructures a tight binding study", "venue": "", "year": 2010 } ]

[ { "abstract": "Overall water splitting, evolving hydrogen and oxygen in a 2:1 stoichiometric ratio, using particulate photocatalysts is a potential means of achieving scalable and economically viable solar hydrogen production. To obtain high solar energy conversion efficiency, the quantum efficiency of the photocatalytic reaction must be increased over a wide range of wavelengths and semiconductors with narrow bandgaps need to be designed. However, the quantum efficiency associated with overall water splitting using existing photocatalysts is typically lower than ten per cent 1 2 Thus, whether a particulate photocatalyst can enable a quantum efficiency of 100 per cent for the greatly endergonic water splitting reaction remains an open question. Here we demonstrate overall water splitting at an external quantum efficiency of up to 96 per cent at wavelengths between 350 and 360 nanometres, which is equivalent to an internal quantum efficiency of almost unity, using a modified aluminium doped strontium titanate (SrTiO 3 :Al) photocatalyst 3 4 By selectively photodepositing the cocatalysts Rh/Cr 2 O 3 (ref. 5 and CoOOH (refs. 3 6 for the hydrogen and oxygen evolution reactions, respectively, on different crystal facets of the semiconductor particles using anisotropic charge transport, the hydrogen and oxygen evolution reactions could be promoted separately. This enabled multiple consecutive forward charge transfers without backward charge transfer, reaching the upper limit of quantum efficiency for overall water splitting. Our work demonstrates the feasibility of overall water splitting free from charge recombination losses and introduces an ideal cocatalyst/photocatalyst structure for efficient water splitting. Water splitting with an internal quantum efficiency of almost unity is achieved using a modified semiconductor photocatalyst that selectively promotes the hydrogen and oxygen evolution reactions on separate crystal facets.", "author_names": [ "Tsuyoshi Takata", "Junzhe Jiang", "Yoshihisa Sakata", "Mamiko Nakabayashi", "Naoya Shibata", "Vikas Nandal", "Kazuhiko Seki", "Takashi Hisatomi", "Kazunari Domen" ], "corpus_id": 218912943, "doc_id": "218912943", "n_citations": 200, "n_key_citations": 1, "score": 1, "title": "Photocatalytic water splitting with a quantum efficiency of almost unity", "venue": "Nature", "year": 2020 }, { "abstract": "Abstract In this work, we investigate the electronic and optical properties of monolayer GeSe and the possibility of enhancement the photocatalytic activities for the water splitting of monolayer GeSe through strain engineering using first principles calculations. Our calculations indicate that monolayer GeSe is a semiconductor with a moderate indirect gap of 1.13 eV at equilibrium and we can control its band gap by biaxial strain. In the presence of biaxial strain e b the semiconductor metal phase transition happens at large compressive strain of 10 and the indirect direct gap transition occurs at e b 4 The optical spectrum of monolayer GeSe are highly anisotropic and biaxial strain can increase the absorption coefficient of monolayer GeSe up to about 6 x 10 5 cm 1. Our calculations demonstrate that monolayer GeSe possesses photocatalytic properties for water splitting at e b 5 and we can enhance its photocatalytic activity by strain.", "author_names": [ "Tuan V Vu", "Nguyen Thanh Binh", "D M Hoat", "Nguyen Van Hieu", "Nguyen Tuan Anh", "Chuong Van Nguyen", "Huynh V Phuc", "Hamad Rahman Jappor", "Mohammed M Obeid", "Nguyen Ngoc Hieu" ], "corpus_id": 204119088, "doc_id": "204119088", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Strain tunable electronic and optical properties of monolayer GeSe: Promising for photocatalytic water splitting applications", "venue": "", "year": 2020 }, { "abstract": "Nano sized TiO2 photocatalytic water splitting technology has great potential for low cost, environmentally friendly solar hydrogen production to support the future hydrogen economy. Presently, the solar to hydrogen energy conversion efficiency is too low for the technology to be economically sound. The main barriers are the rapid recombination of photo generated electron/hole pairs as well as backward reaction and the poor activation of TiO2 by visible light. In response to these deficiencies, many investigators have been conducting research with an emphasis on effective remediation methods. Some investigators studied the effects of addition of sacrificial reagents and carbonate salts to prohibit rapid recombination of electron/hole pairs and backward reactions. Other research focused on the enhancement of photocatalysis by modification of TiO2 by means of metal loading, metal ion doping, dye sensitization, composite semiconductor, anion doping and metal ion implantation. This paper aims to review the up to date development of the above mentioned technologies applied to TiO2 photocatalytic hydrogen production. Based on the studies reported in the literature, metal ion implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range. Therefore, they play an important role in the development of efficient photocatalytic hydrogen production.", "author_names": [ "Meng Ni", "Michael K H Leung", "Dennis Yiu Cheong Leung", "K Sumathy" ], "corpus_id": 93782298, "doc_id": "93782298", "n_citations": 3240, "n_key_citations": 24, "score": 0, "title": "A review and recent developments in photocatalytic water splitting using TiO2 for hydrogen production", "venue": "", "year": 2007 }, { "abstract": "Conjugated carbon nitride (CN) is an emerging and promising semiconductor photocatalyst for water photolysis owing to its unique properties. However, the traditional thermally induced polymerization of N containing precursors typically produces melon based CN solids with amorphous or semi crystalline structures with only moderate photocatalytic performance. Many strategies have been developed to prepare crystalline CNs (CCNs) such as high temperature and high pressure routes, ionothermal synthesis, and microwave assisted synthesis. In this Minireview, we summarize the progress that has been made in the synthesis of CCNs and their application in photocatalytic water splitting reactions. Three kinds of CCNs are mainly discussed according to their polymeric subunits. Challenges associated with CCNs and their future development are also included.", "author_names": [ "Lihua Lin", "Zhiyang Yu", "Xinchen Wang" ], "corpus_id": 53041782, "doc_id": "53041782", "n_citations": 226, "n_key_citations": 1, "score": 0, "title": "Crystalline Carbon Nitride Semiconductors for Photocatalytic Water Splitting.", "venue": "Angewandte Chemie", "year": 2019 }, { "abstract": "Abstract Water splitting for hydrogen production under light irradiation is an ideal system to provide renewable energy sources and to reduce global warming effects. Even though significant efforts have been devoted to fabricate advanced nanocomposite materials, the main challenge persists, which is lower efficiency and selectivity towards H2 evolution under solar energy. In this review, recent developments in photo catalysts, fabrication of novel heterojunction constructions and factors influencing the photocatalytic process for dynamic H2 production have been discussed. In the mainstream, recent developments in TiO2 and g C3N4 based photo catalysts and their potential for H2 production are extensively studied. The improvements have been classified as strategies to improve different factors of photocatalytic water splitting such as Z scheme systems and influence of operating parameters such as band gap, morphology, temperature, light intensity, oxygen vacancies, pH, and sacrificial reagents. Moreover, thermodynamics for selective photocatalytic H2 production are critically discussed. The advances in photo reactors and their role to provide more light distribution and surface area contact between catalyst and light were systematically described. By applying the optimum operating parameters and new engineering approach on photoreactor, the efficiency of semiconductor photocatalysts for H2 production can be enhanced. The future research and perspectives for photocatalytic water splitting were also suggested.", "author_names": [ "Nur Fajrina", "Muhammad Tahir" ], "corpus_id": 106296401, "doc_id": "106296401", "n_citations": 236, "n_key_citations": 0, "score": 0, "title": "A critical review in strategies to improve photocatalytic water splitting towards hydrogen production", "venue": "", "year": 2019 }, { "abstract": "Abstract As the world decides on the next giant step for the renewable energy revolution, scientists have begun to reinforce their headlong dives into the exploitation of solar energy. Hitherto, numerous attempts are made to imitate the natural photosynthesis of plants by converting solar energy into chemical fuels which resembles the \"Z scheme\" process. A recreation of this system is witnessed in artificial Z scheme photocatalytic water splitting to generate hydrogen (H2) This work outlines the recent significant implication of the Z scheme system in photocatalytic water splitting, particularly in the role of electron mediator and the key factors that improve the photocatalytic performance. The Review begins with the fundamental rationales in Z scheme water splitting, followed by a survey on the development roadmap of three different generations of Z scheme system: 1) PS A/D PS (first generation) 2) PS C PS (second generation) and 3) PS PS (third generation) Focus is also placed on the scaling up of the \"leaf to tree\" challenge of Z scheme water splitting system, which is also known as Z scheme photocatalyst sheet. A detailed investigation of the Z scheme system for achieving H2 evolution from past to present accompanied with in depth discussion on the key challenges in the area of Z scheme photocatalytic water splitting are provided.", "author_names": [ "Boon-Junn Ng", "Lutfi Kurnianditia Putri", "Xin Ying Kong", "Yee Wen Teh", "Pooria Pasbakhsh", "Siang-Piao Chai" ], "corpus_id": 214503446, "doc_id": "214503446", "n_citations": 71, "n_key_citations": 0, "score": 0, "title": "Z Scheme Photocatalytic Systems for Solar Water Splitting", "venue": "Advanced science", "year": 2020 }, { "abstract": "Photocatalytic and photoelectrochemical water splitting under irradiation by sunlight has received much attention for production of renewable hydrogen from water on a large scale. Many challenges still remain in improving energy conversion efficiency, such as utilizing longer wavelength photons for hydrogen production, enhancing the reaction efficiency at any given wavelength, and increasing the lifetime of the semiconductor materials. This introductory review covers the fundamental aspects of photocatalytic and photoelectrochemical water splitting. Controlling the semiconducting properties of photocatalysts and photoelectrode materials is the primary concern in developing materials for solar water splitting, because they determine how much photoexcitation occurs in a semiconductor under solar illumination and how many photoexcited carriers reach the surface where water splitting takes place. Given a specific semiconductor material, surface modifications are important not only to activate the semiconductor for water splitting but also to facilitate charge separation and to upgrade the stability of the material under photoexcitation. In addition, reducing resistance loss and forming p n junction have a significant impact on the efficiency of photoelectrochemical water splitting. Correct evaluation of the photocatalytic and photoelectrochemical activity for water splitting is becoming more important in enabling an accurate comparison of a number of studies based on different systems. In the latter part, recent advances in the water splitting reaction under visible light will be presented with a focus on non oxide semiconductor materials to give an overview of the various problems and solutions.", "author_names": [ "Takashi Hisatomi", "Jun Kubota", "Kazunari Domen" ], "corpus_id": 11321291, "doc_id": "11321291", "n_citations": 2491, "n_key_citations": 14, "score": 0, "title": "Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting.", "venue": "Chemical Society reviews", "year": 2014 }, { "abstract": "Abstract We report the remarkable production of H2 and H2O2 from pure water using porous brookite TiO2 nanoflutes decorated with Pt nanoparticles through two electron photocatalytic intermediate water splitting (PIWS) The H2 production rate from deionized water (pH ~7.0) was 9.8 0.6 mmol mg 1 h 1, more than 12 fold and 230 fold higher than the reported TiO2 based photocatalytic overall water splitting (POWS) and H2/H2O2 production systems, respectively. The apparent quantum yields (AQY) value can achieve 43.4% which is the highest value compared with the reported TiO2 based POWS systems and the commercial value for PIWS is ~9 fold higher than that for POWS even ignoring the separation cost. The mechanism of the distinct performance was confirmed by DFT and experimental measurements. The present work provides a feasible strategy to significantly improve the process efficiency and value of photocatalytic water splitting in both pure water and seawater using natural sunlight.", "author_names": [ "Shuang Cao", "Ting Shan Chan", "Ying-Rui Lu", "Xinghua Shi", "Bing Fu", "Hongmei Li", "Kang Liu", "Sarah Alzuabi", "Ping Cheng", "Min Liu", "Tao Li", "Xiaobo Chen", "Lingyu Piao" ], "corpus_id": 209731294, "doc_id": "209731294", "n_citations": 35, "n_key_citations": 0, "score": 0, "title": "Photocatalytic pure water splitting with high efficiency and value by Pt/porous brookite TiO2 nanoflutes", "venue": "", "year": 2020 }, { "abstract": "Abstract Recently, g C 3 N 4 has exhibited excellent catalytic performances in photocatalytic water splitting for H 2 and O 2 generation, degradation of pollutants and CO 2 reduction. However, the bulk g C 3 N 4 demonstrates some disadvantages such as low specific surface area, high defect density, fast recombination possibility of photogenerated electron hole pairs, and non recyclable characteristics, leading to low photocatalytic performance and efficiency. The three dimensional (3D) network like g C 3 N 4 composite materials constructed by nanotechnology can effectively improve the adsorption capacity, light response, structure stability and recyclability of photocatalysts, which results in a significant increase in the photocatalytic performance and utilization. It is a novel way to achieve high efficient separation of photogenerated electron hole pairs and improve photocatalytic activity. In this review, the recent research progresses especially the synthesis strategy of 3D g C 3 N 4 composite photocatalysts and their applications for photocatalytic water splitting, degradation of organic pollutants and CO 2 reduction are firstly and systematically introduced and discussed. The review and prospect of 3D g C 3 N 4 composite materials can provide some new ideas and directions for the research and development of 3D g C 3 N 4 composite photocatalysts with high activity, strong adsorption, facile recyclability, and no secondary pollution.", "author_names": [ "Xibao Li", "Jie Xiong", "Xiaoming Gao", "Juntong Huang", "Zhijun Feng", "Zhi Chen", "Yongfa Zhu" ], "corpus_id": 197611946, "doc_id": "197611946", "n_citations": 106, "n_key_citations": 1, "score": 0, "title": "Recent advances in 3D g C3N4 composite photocatalysts for photocatalytic water splitting, degradation of pollutants and CO2 reduction", "venue": "Journal of Alloys and Compounds", "year": 2019 }, { "abstract": "Black phosphorus (BP) has recently drawn tremendous attention in photocatalysis for its excellent optical properties. However, limited by the rapid recombination of photogenerated carriers, the use of BP for photocatalytic water splitting still remains a huge challenge. Herein, we fabricate a black/red phosphorus (BP/RP) hetero phase junction photocatalyst by a wet chemistry method to successfully promote the interfacial charge separation and thus achieve Z scheme photocatalytic water splitting without using sacrificial agents. The Z scheme mechanism was unambiguously confirmed by time resolved transient absorption spectroscopy. This work provides a novel insight into the interface design of hetero phase junction with atomic precision.", "author_names": [ "Fulai Liu", "Rui Shi", "Zhuan Wang", "Yuxiang Weng", "Chi-Ming Che", "Yong Chen" ], "corpus_id": 195659155, "doc_id": "195659155", "n_citations": 116, "n_key_citations": 1, "score": 0, "title": "Direct Z Scheme Hetero phase Junction of Black/Red Phosphorus for Photocatalytic Water Splitting.", "venue": "Angewandte Chemie", "year": 2019 } ]

[ { "abstract": "In recent years, quasi one dimensional semiconductor nanowires have attracted numerous research interests in the field of optoelectronic devices. Indium arsenide (InAs) nanowire, an III V compound semiconductor structure with a narrow bandgap, shows high electron mobility and high absorption from the visible to the mid wave infrared (MWIR) holding promise for roomtemperature high performance infrared photodetectors. Therefore, the material growth, device preparation, and performance characteristics have attracted increasing attention, enabling high sensitivity InAs nanowire photodetector from the visible to the MWIR at room temperature. This review starts by discussing the growth process of the low dimensional structure and elementary properties of the material, such as the crystalline phase, mobility, morphology, surface states, and metal contacts. Then, three solutions, including the visible light assisted infrared photodetection technology, the vertical nanowire array technology, and band engineering by the growth of InAsSb nanowires with increasing Sb components, are elaborated to obtain longer cut off wavelength MWIR photodetectors based on single InAs nanowire and its heterojunction structure. Finally, the potentials and challenges of the state of the art optoelectronic technologies for InAs nanowire MWIR photodetectors are summarized and compared, and preliminary suggestions for the technical development route and prospects are presented. This review mainly delineates the research progress of material growth, device fabrication and performance characterization of InAs nanowire MWIR photodetectors, providing a reference for the development of the next generation high performance photodetectors over a wide spectrum range.", "author_names": [ "Tengfei Xu", "Hailu Wang", "Xiaoyao Chen", "Man Luo", "Lili Zhang", "Yueming Wang", "Fansheng Chen", "Chongxin Shan", "Chen-Hui Yu" ], "corpus_id": 214766570, "doc_id": "214766570", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Recent progress on infrared photodetectors based on InAs and InAsSb nanowires.", "venue": "Nanotechnology", "year": 2020 }, { "abstract": "As IV VI compound, tin telluride belongs to direct band gap semiconductor materials. Under the condition of room temperature and atmospheric pressure, tin telluride has a stable face centered cubic crystal structure. Being a topological crystal insulator, tin telluride has a highly symmetrical crystal structure. Due to its helical multiple surface states and strong topological protection characteristics, tin telluride can be used to fabricate new electronic devices without energy consumption. Moreover, on account of its excellent properties such as band gap free topological surface state and narrow band gap posture, it has great potential in the field of preparing new photodetectors with wide spectral response from ultraviolet, visible light to infrared. In addition, because of its high mobility at room temperature, tin telluride is expected to be used for high performance photoelectric detection with ultra fast response speed. In this review, the preparation methods, crystal structures and properties of tin telluride materials were summarized from the point of view that they were suitable for photodetectors. And the research progress of tin telluride in infrared photoelectric detection in recent years was summarized. Then the development potential of tin telluride in the field of photodetectors was prospected, and Shou Gao Ri Qi :2020 11 21; Xiu Ding Ri Qi :2020 12 25 Ji Jin Xiang Mu :Guo Jia Zhong Dian Yan Fa Ji Hua (2019YFB2203404);Yun Nan Sheng Chuang Xin Tuan Dui Xiang Mu (2018HC020) Di 50 Juan Di 1 Qi Hong Wai Yu Ji Guang Gong Cheng 2021 Nian 1 Yue Vol.50 No.1 Infrared and Laser Engineering Jan. 2021", "author_names": [ "Song Li Yuan Liyuan Song", "Tang Li Bin Libin Tang", "Hao Qun Qun Hao" ], "corpus_id": 235852905, "doc_id": "235852905", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Preparation, structure and properties of tin telluride and its research progress in infrared photodetection (Invited)", "venue": "", "year": 2021 }, { "abstract": "Recently,it becomes more essential of higher quality of the semiconductor optoelectronic devices with the progression of the economy informationisation and the armament informationisation.As one of the key components,optoelectronic detector attracts so much attention from the whole world.Fortunately it has been making huge progress in this area.In this paper,we introduce the research and development of full/multiple spectrum Focal Plane Array(FPA) detectors of III V semiconductors,including the quantum well infrared,AlGaN violet,InGaAs near infrared room temperature and Sb compound FPA detectors.", "author_names": [ "Chen Lianghui" ], "corpus_id": 111757312, "doc_id": "111757312", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Development of III V semiconductor FPA photodetectors of full optical spectrum", "venue": "", "year": 2008 }, { "abstract": "One dimensional (1D) semiconductor nanowires (NWs) have drawn considerable research attention over the past few decades because of their unique properties and potential applications in nanoelectronics, photonics, luminescent materials, lasing materials, and biological and medical sensing. 1 3 Impressive progress has been demonstrated in highly effi cient light sources (nanolasers) waveguides, fi eld effect transistors and photodetectors based on group IV elements (Si and Ge) 4 III V compound semiconductors (GaN and GaAs) 2 5 and semiconducting oxides (ZnO, SnO 2 and In 2 O 3 6 7 Owing to its direct bandgap (ca. 1.74 eV at room temperature) good absorption ability, and excellent photosensitivity, 8 9 CdSe is recognized as a promising light harvesting material to be applied in optoelectronics. Especially, the fundamental emission of CdSe falls in the near infrared (NIR) region, and biosensors operating in this region can avoid interference from biological media such as tissue autofl uorescence and scattering light, and thereby facilitate relatively interference free sensing. 10", "author_names": [ "Rui Chen", "M Iqbal Bakti Utama", "Zeping Peng", "Bo Peng", "Qihua Xiong", "Handong Sun" ], "corpus_id": 205239086, "doc_id": "205239086", "n_citations": 67, "n_key_citations": 1, "score": 0, "title": "Excitonic properties and near infrared coherent random lasing in vertically aligned CdSe nanowires.", "venue": "Advanced materials", "year": 2011 }, { "abstract": "The 2 4 mm band is a very important infrared atmospheric window. Lasers operating in this band have a wide range of applications in gas detection, medical application and industrial processing. The low dimensional structure of antiminide semiconductor materials has the unique advantage of narrow forbidden band, direct transition luminescence, and is an ideal material system for realizing mid infrared semiconductor lasers. In recent years, research on antimonide semiconductor lasers at home and abroad has made important progress, achieving wavelength expansion of quantum well luminescence, room temperature continuous lasing of high power single chip and laser bars, and continuous room temperature continuous operation of multi band single mode lasers. Due to the complex composition of the low dimensional materials of the antimonide and the special interface Shou Gao Ri Qi :2020 10 26; Xiu Ding Ri Qi :2020 11 25 Ji Jin Xiang Mu :Guo Jia Zi Ran Ke Xue Ji Jin (61790580,61790581,61790582,61790583);Yan Dong Sheng Zhong Dian Yan Fa Ji Hua (2020B0303020001, 2018B030329001) Zuo Zhe Jian Jie :Yang Cheng Ao (1990 ,Nan ,Zhu Li Yan Jiu Yuan ,Bo Shi ,Zhu Yao Cong Shi Ti Hua Wu Hong Wai Ji Guang Qi Fang Mian De Yan Jiu Email:[email protected] Tong Xun Zuo Zhe :Zhang Yu (1981 ,Nan ,Fu Yan Jiu Yuan ,Bo Shi ,Zhu Yao Cong Shi Ti Hua Wu Hong Wai Ban Dao Ti Ji Guang Qi Fang Mian De Yan Jiu Email:[email protected] Niu Zhi Chuan (1963 ,Nan ,Yan Jiu Yuan ,Bo Shi Sheng Dao Shi ,Bo Shi ,Zhu Yao Cong Shi Di Wei Ban Dao Ti Guang Dian Cai Liao Yu Liang Zi Qi Jian Fang Mian De Yan Jiu Email:[email protected] Di 49 Juan Di 12 Qi Hong Wai Yu Ji Guang Gong Cheng 2020 Nian 12 Yue Vol.49 No.12 Infrared and Laser Engineering Dec. 2020", "author_names": [ "Yang Cheng Ao Chengao Yang", "Zhang Yi Yi Zhang", "Shang Jin Ming Jinming Shang", "Chen Yi Hang Yihang Chen", "Wang Tian Fang Tianfang Wang", "Tong Hai Bao Haibao Tong", "Ren Zheng Wei Zhengwei Ren", "Zhang Yu Yu Zhang", "Xu Ying Qiang Yingqiang Xu", "Niu Zhi Chuan Zhichuan Niu" ], "corpus_id": 234757574, "doc_id": "234757574", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research progress of 2 4 mm mid infrared antimonide semiconductor lasers (Invited)", "venue": "", "year": 2020 }, { "abstract": "Infrared detection plays an important role in cutting edge fields such as biomedicine, smart cities, and space exploration. In recent years, a new type of nanoscale semiconductor represented by two dimensional materials is one of the candidates for a new generation of infrared photodetection technology. This is due to the fact that some index of two dimensional materials device have exceeded the theoretical limits of traditional thin film devices, such as detection sensitivity, ultralow dark current, high working temperature, etc. Two dimensional materials can easily be controlled by local field. In this review, the mechanism of three local fields to achieve high performance at room temperature were introduced in the first part, including ferroelectric local field, the interlayer built in electric field, and the in plane built in electric field. Secondly, we introduced the photoelectric enhancement methods of unilateral depletion heterojunction and surface plasmon structure to solve the problem of low quantum efficiency and low light absorption caused by atomic thin effect of two dimensional materials. Finally, we showed some applications of two dimensional materials in infrared photodetection field. The exploration reveals the potential and prospect of the novel two dimensional semiconductor in the field of infrared photodetection, which provides some new methods and ideas for the new generation infrared detector technology.", "author_names": [ "Xu Hang Yu Hangyu Xu", "Wang Peng Peng Wang", "Chen Xiao Shuang Xiaoshuang Chen", "Hu Wei Da Weida Hu" ], "corpus_id": 235847116, "doc_id": "235847116", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Research progress of two dimensional semiconductor infrared photodetector (Invited)", "venue": "", "year": 2021 }, { "abstract": "Compound semiconductor mid wavelength infrared photodetectors operating at room temperature are the sensors of choice for demanding applications such as thermal imaging, heat seeking, and spectroscopy. However, those detectors suffer from high dark current and thus normally require additional cooling accessories. In this work, we argue for the fundamental feasibility that by using nanowires coupled with plasmonic nano antennae as photoabsorbers, the dark current can be largely reduced compared with typical planar devices. To demonstrate the idea, we simulate the device characteristics, such as dark current, responsivity, and detectivity, of InAsSb0.07 nanowire photodetectors, and compare those properties with the best research InAs photovoltaic diodes. The results show that the designed nanowire detectors offer over one order lower dark current and enable a peak detectivity of 7.0x1010 cm Hz1/2W 1 at 3.5 mm. We believe this work will provide a guidance to the design of nanowire based MWIR photodetectors and stimulate additional experimental and theoretical research studies.", "author_names": [ "Dingkun Ren", "Zixuan Rong", "C Ta Thanh Minh", "Alan C Farrell", "Xiao Meng", "Diana L Huffaker" ], "corpus_id": 139777538, "doc_id": "139777538", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Feasibility of room temperature mid wavelength infrared photodetectors using InAsSb nanostructured photoabsorbers", "venue": "OPTO", "year": 2018 }, { "abstract": "Two dimensional (2D) materials, such as graphene, transition metal dichalcogenides (TMDs) black phosphorus (BP) and related derivatives, have attracted great attention due to their advantages of flexibility, strong light matter interaction, broadband absorption and high carrier mobility, and have become a powerful contender for next generation infrared photodetectors. However, since the thickness of two dimensional materials is on the order of nanometers, the absorption of two dimensional materials is very weak, which limits the detection performance of 2D materials based infrared photodetector. In order to solve this problem, scientific researchers have tried to use optimized device structures to combine with two dimensional materials for improving the performance of infrared photodetector. In this review, we review the progress of room temperature infrared photodetectors with hybrid structure based on 2D materials in recent years, focusing mainly on 2D nD (n 0, 1, 2) heterostructures, the integration between 2D materials and on chip or plasmonic structure. Finally, we summarize the current challenges and point out the future development direction.", "author_names": [ "Tian-Min Liu", "Lei Tong", "Xinyu Huang", "Lei Ye" ], "corpus_id": 119252717, "doc_id": "119252717", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Room temperature infrared photodetectors with hybrid structure based on two dimensional materials", "venue": "", "year": 2019 }, { "abstract": "Ultra sensitive single photon detection is a key technology for the development of optical quantum information and quantum manipulation. It is of important scientific significance and application value to realize high efficiency, high sensitivity, low power and low cost single photon photodetectors. There is still a large gap between visible single photon detector based on silicon and infrared ones in terms of the cost and performance. Exploring the technology of infrared single photon detection with novel materials and mechanism has become the urgent needs in the field of photodetection. In recent years, low dimensional materials have offered a new possibility for realizing high gain, room temperature and broad band photodetectors due to their unique physical and chemical properties. The research on the low dimensional materials based photodetectors with good performance has also become a hot topic in the field of infrared photodetection. In this review, the basic principles of traditional avalanche infrared photodetectors were introduced firstly. On this basis, the latest development of avalanche devices based on novel low dimensional materials was summarized. Then the new gain amplification mechanism of the photodetector based on photogating effect was discussed and the structure as well as the performance of the devices were reviewed. Finally, the future developing directions and challenges of the infrared single photon detection technology were prospected.", "author_names": [ "Wu Jing Yuan Jingyuan Wu", "Liu Zhao Guo Zhaoguo Liu", "Zhang Tong Tong Zhang" ], "corpus_id": 234066633, "doc_id": "234066633", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Research progress of infrared single photon detection with high gain (Invited)", "venue": "", "year": 2021 }, { "abstract": "In recent years, infrared photodetectors have attracted increasing interest due to their promising applications in both military and civil areas. To further realize room temperature, wide spectrum, high sensitivity, fast response and low power consumption infrared photodetectors, low dimension semiconductors are considered as potential channel materials and have been studied widely. Among them, nanowires have special electrical and photoelectrical characteristics, showing enormous advantages in the applications of infrared photodetectors such as small size, low power consumption, high light absorption efficiency, abundant surface states, outstanding ability to separate and collect photoelectrons, good compatibility with Si complementary metal oxide semiconductor (CMOS) technology and so on. At present, nanowires infrared photodetectors are going through continuous progress and breakthrough. In this review, recent advances in semiconductor nanowires infrared photodetectors were outlined in details. At the beginning, the basic characteristics, material choice and preparation methods of nanowires were introduced. Subsequently, many nanowires including binary and ternary compound semiconductors for the use of infrared detection were presented and their current detectable levels were illustrated precisely. Many methods of further improving their detecting performances were also classified and summarized, including constructing heterostructures, applying external field and integrating with other functional devices. On the basis of the above mentioned advances, a comparison of advantages and disadvantages among different nanowires infrared detectors was given. In the end, the future development trend was indicated based on the challenges in this area and preliminary suggestions for the technical development route were presented.", "author_names": [ "Guo Ya Nan Yanan Guo", "Liu Dong Dong Liu", "Miao Cheng Cheng Chengcheng Miao", "Sun Jia Min Jiamin Sun", "Yang Zai Xing Zai-xing Yang" ], "corpus_id": 234004517, "doc_id": "234004517", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Recent advances in semiconductor nanowires infrared photodetectors (Invited)", "venue": "", "year": 2021 } ]

[ { "abstract": "Highly stable antimonene, as the cousin of phosphorene from group VA, has opened up exciting realms in the two dimensional (2D) materials family. However, pristine antimonene is an indirect band gap semiconductor, which greatly restricts its applications for optoelectronics devices. Identifying suitable materials, both responsive to incident photons and efficient for carrier transfer, is urgently needed for ultrathin devices. Herein, by means of first principles computations we found that it is rather feasible to realize a new class of 2D materials with a direct bandgap and high carrier mobility, namely antimonene oxides with different content of oxygen. Moreover, these tunable direct bandgaps cover a wide range from 0 to 2.28 eV, which are crucial for solar cell and photodetector applications. Especially, the antimonene oxide (18Sb 18O) is a 2D topological insulator with a sizable global bandgap of 177 meV, which has a nontrivial Z2 topological invariant in the bulk and the topological states on the edge. Our findings not only introduce new vitality into 2D group VA materials family and enrich available candidate materials in this field but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexible electronics and optoelectronics devices.", "author_names": [ "Shengli Zhang", "Wenhan Zhou", "Yandong Ma", "Jianping Ji", "Bo Cai", "Shengyuan A Yang", "Zhen Zhu", "Zhongfang Chen", "Haibo Zeng" ], "corpus_id": 206739209, "doc_id": "206739209", "n_citations": 194, "n_key_citations": 0, "score": 1, "title": "Antimonene Oxides: Emerging Tunable Direct Bandgap Semiconductor and Novel Topological Insulator.", "venue": "Nano letters", "year": 2017 }, { "abstract": "Solar water splitting via multi junction semiconductor photoelectrochemical cells provides direct conversion of solar energy to stored chemical energy as hydrogen bonds. Economical hydrogen production demands high conversion efficiency to reduce balance of systems costs. For sufficient photovoltage, water splitting efficiency is proportional to the device photocurrent, which can be tuned by judicious selection and integration of optimal semiconductor bandgaps. Here, we demonstrate highly efficient, immersed water splitting electrodes enabled by inverted metamorphic epitaxy and a transparent graded buffer that allows the bandgap of each junction to be independently varied. Voltage losses at the electrolyte interface are reduced by 0.55 V over traditional, uniformly p doped photocathodes by using a buried p n junction. Advanced on sun benchmarking, spectrally corrected and validated with incident photon to current efficiency, yields over 16% solar to hydrogen efficiency with GaInP/GaInAs tandem absorbers, representing a 60% improvement over the classical, high efficiency tandem III V device. Solar water splitting efficiency can be enhanced by careful bandgap selection in multi junction semiconductor structures. Young et al. demonstrate a route that allows independent bandgap tuning of each junction in an immersed water splitting device, enabling a solar to hydrogen efficiency of over 16%", "author_names": [ "James L Young", "Myles A Steiner", "Henning Doscher", "John A Turner", "Todd G Deutsch" ], "corpus_id": 114434893, "doc_id": "114434893", "n_citations": 203, "n_key_citations": 0, "score": 0, "title": "Direct solar to hydrogen conversion via inverted metamorphic multi junction semiconductor architectures", "venue": "", "year": 2017 }, { "abstract": "Methylammonium lead iodide perovskites are considered direct bandgap semiconductors. Here we show that in fact they present a weakly indirect bandgap 60 meV below the direct bandgap transition. This is a consequence of spin orbit coupling resulting in Rashba splitting of the conduction band. The indirect nature of the bandgap explains the apparent contradiction of strong absorption and long charge carrier lifetime. Under hydrostatic pressure from ambient to 325 MPa, Rashba splitting is reduced due to a pressure induced reduction in local electric field around the Pb atom. The nature of the bandgap becomes increasingly more direct, resulting in five times faster charge carrier recombination, and a doubling of the radiative efficiency. At hydrostatic pressures above 325 MPa, MAPI undergoes a reversible phase transition resulting in a purely direct bandgap semiconductor. The pressure induced changes suggest epitaxial and synthetic routes to higher efficiency optoelectronic devices.", "author_names": [ "Tianyi Wang", "Benjamin Daiber", "Jarvist Moore Frost", "Sander A Mann", "Erik C Garnett", "Aron Walsh", "Bruno Ehrler" ], "corpus_id": 44001654, "doc_id": "44001654", "n_citations": 173, "n_key_citations": 0, "score": 0, "title": "Indirect to direct bandgap transition in methylammonium lead halide perovskite", "venue": "", "year": 2016 }, { "abstract": "Recently rediscovered black phosphorus is a layered semiconductor with promising electronic and photonic properties. Dynamic control of its bandgap can allow for the exploration of new physical phenomena. However, theoretical investigations and photoemission spectroscopy experiments indicate that in its few layer form, an exceedingly large electric field in the order of several volts per nanometre is required to effectively tune its bandgap, making the direct electrical control unfeasible. Here we reveal the unique thickness dependent bandgap tuning properties in intrinsic black phosphorus, arising from the strong interlayer electronic state coupling. Furthermore, leveraging a 10 nm thick black phosphorus, we continuously tune its bandgap from ~300 to below 50 meV, using a moderate displacement field up to 1.1 V nm 1. Such dynamic tuning of bandgap may not only extend the operational wavelength range of tunable black phosphorus photonic devices, but also pave the way for the investigation of electrically tunable topological insulators and semimetals.", "author_names": [ "Bingchen Deng", "Vy Tran", "Yujun Xie", "Hao Jiang", "Cheng Li", "Qiushi Guo", "Xiaomu Wang", "He Tian", "Steven J Koester", "Han Wang", "Judy J Cha", "Qiangfei Xia", "Li Yang", "Fengnian Xia" ], "corpus_id": 5584013, "doc_id": "5584013", "n_citations": 149, "n_key_citations": 1, "score": 0, "title": "Efficient electrical control of thin film black phosphorus bandgap", "venue": "Nature communications", "year": 2017 }, { "abstract": "The possibility of tailoring physical properties by changing the number of layers in van der Waals crystals is one of the driving forces behind the emergence of two dimensional materials. One example is bulk MoS2, which changes from an indirect gap semiconductor to a direct bandgap semiconductor in the monolayer form. Here, we show a much bigger tuning range with a complete switching from a metal to a semiconductor in atomically thin PtSe2 as its thickness is reduced. Crystals with a thickness of ~13 nm show metallic behavior with a contact resistance as low as 70 O*um. As they are thinned down to 2.5 nm and below, we observe semiconducting behavior. In such thin crystals, we demonstrate ambipolar transport with a bandgap smaller than 2.2 eV and an on/off ratio of ~105. Our results demonstrate that PtSe2 possesses an unusual behavior among 2D materials, enabling novel applications in nano and optoelectronics.The electronic band structure of van der Waals crystals is strongly sensitive to the number of layers. Here, the authors observe a thickness dependent metal to semiconductor transition in layered PtSe2 by means of electrical transport measurements.", "author_names": [ "Alberto Ciarrocchi", "Ahmet Avsar", "Dmitry Ovchinnikov", "Andras Kis" ], "corpus_id": 3648745, "doc_id": "3648745", "n_citations": 151, "n_key_citations": 1, "score": 0, "title": "Thickness modulated metal to semiconductor transformation in a transition metal dichalcogenide", "venue": "Nature Communications", "year": 2018 }, { "abstract": "Few layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus (BP) offers and could be feasibly synthesized by simple solution based methods. It is comprised of non covalently bound parallel Te chains, among which covalent like feature appears. This feature is, we believe, another demonstration of the previously found covalent like quasi bonding (CLQB) where wavefunction hybridization does occur. The strength of this inter chain CLQB is comparable with that of intra chain covalent bonding, leading to closed stability of several Te allotropes. It also introduces a tunable bandgap varying from nearly direct 0.31 eV (bulk) to indirect 1.17 eV (2L) and four (two) complex, highly anisotropic and layer dependent hole (electron) pockets in the first Brillouin zone. It also exhibits an extraordinarily high hole mobility ~10$^5$ cm$^2$/Vs) and strong optical absorption along the non covalently bound direction, nearly isotropic and layer dependent optical properties, large ideal strength over 20% better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes. All these results manifest that the few layer Te is an extraordinary high mobility, high optical absorption, intrinsic anisotropy, low cost fabrication, tunable bandgap, better environmental stability and nearly direct bandgap semiconductor. This \"one dimension like\" few layer Te, together with other geometrically similar layered materials, may promote the emergence of a new family of layered materials.", "author_names": [ "Jingsi Qiao", "Yuhao Pan", "Feng Yang", "Cong Wang", "Yang Chai", "Wei Ji" ], "corpus_id": 103425636, "doc_id": "103425636", "n_citations": 116, "n_key_citations": 1, "score": 0, "title": "Few layer Tellurium: one dimensional like layered elementary semiconductor with striking physical properties", "venue": "", "year": 2017 }, { "abstract": "Since the establishment of perovskite solar cells (PSCs) there has been an intense search for alternative materials to replace lead and improve their stability toward moisture and light. As single metal perovskite structures have yielded unsatisfactory performances, an alternative is the use of double perovskites that incorporate a combination of metals. To this day, only a handful of these compounds have been synthesized, but most of them have indirect bandgaps and/or do not have bandgaps energies well suited for photovoltaic applications. Here we report the synthesis and characterization of a unique mixed metal <111> oriented layered perovskite, Cs4CuSb2Cl12 (1) that incorporates Cu2+ and Sb3+ into layers that are three octahedra thick (n 3) In addition to being made of abundant and nontoxic elements, we show that this material behaves as a semiconductor with a direct bandgap of 1.0 eV and its conductivity is 1 order of magnitude greater than that of MAPbI3 (MA methylammonium) Furthermore, 1 has high photo and thermal stability and is tolerant to humidity. We conclude that 1 is a promising material for photovoltaic applications and represents a new type of layered perovskite structure that incorporates metals in 2+ and 3+ oxidation states, thus significantly widening the possible combinations of metals to replace lead in PSCs.", "author_names": [ "Brenda Cabral Vargas", "Estrella Ramos", "Enrique Perez-Gutierrez", "Juan Carlos Alonso", "Diego Solis-Ibarra" ], "corpus_id": 27145307, "doc_id": "27145307", "n_citations": 112, "n_key_citations": 1, "score": 0, "title": "A Direct Bandgap Copper Antimony Halide Perovskite.", "venue": "Journal of the American Chemical Society", "year": 2017 }, { "abstract": "The development of non equilibrium group IV nanoscale alloys is critical to achieving new functionalities, such as the formation of a direct bandgap in a conventional indirect bandgap elemental semiconductor. Here, we describe the fabrication of uniform diameter, direct bandgap Ge1 xSnx alloy nanowires, with a Sn incorporation up to 9.2 at. far in excess of the equilibrium solubility of Sn in bulk Ge, through a conventional catalytic bottom up growth paradigm using noble metal and metal alloy catalysts. Metal alloy catalysts permitted a greater inclusion of Sn in Ge nanowires compared with conventional Au catalysts, when used during vapour liquid solid growth. The addition of an annealing step close to the Ge Sn eutectic temperature (230 degC) during cool down, further facilitated the excessive dissolution of Sn in the nanowires. Sn was distributed throughout the Ge nanowire lattice with no metallic Sn segregation or precipitation at the surface or within the bulk of the nanowires. The non equilibrium incorporation of Sn into the Ge nanowires can be understood in terms of a kinetic trapping model for impurity incorporation at the triple phase boundary during growth.", "author_names": [ "Subhajit Biswas", "Jessica Doherty", "Dzianis Saladukha", "Quentin M Ramasse", "Dipanwita Majumdar", "Moneesh Upmanyu", "Achintya Singha", "Tomasz J Ochalski", "Michael A Morris", "Justin D Holmes" ], "corpus_id": 4778905, "doc_id": "4778905", "n_citations": 74, "n_key_citations": 1, "score": 0, "title": "Non equilibrium induction of tin in germanium: towards direct bandgap Ge1 xSnx nanowires", "venue": "Nature communications", "year": 2016 }, { "abstract": "Epitaxy is a process by which a thin layer of one crystal is deposited in an ordered fashion onto a substrate crystal. The direct epitaxial growth of semiconductor heterostructures on top of crystalline superconductors has proved challenging. Here, however, we report the successful use of molecular beam epitaxy to grow and integrate niobium nitride (NbN) based superconductors with the wide bandgap family of semiconductors silicon carbide, gallium nitride (GaN) and aluminium gallium nitride (AlGaN) We apply molecular beam epitaxy to grow an AlGaN/GaN quantum well heterostructure directly on top of an ultrathin crystalline NbN superconductor. The resulting high mobility, two dimensional electron gas in the semiconductor exhibits quantum oscillations, and thus enables a semiconductor transistor an electronic gain element to be grown and fabricated directly on a crystalline superconductor. Using the epitaxial superconductor as the source load of the transistor, we observe in the transistor output characteristics a negative differential resistance a feature often used in amplifiers and oscillators. Our demonstration of the direct epitaxial growth of high quality semiconductor heterostructures and devices on crystalline nitride superconductors opens up the possibility of combining the macroscopic quantum effects of superconductors with the electronic, photonic and piezoelectric properties of the group III/nitride semiconductor family.", "author_names": [ "Rusen Yan", "Guru Khalsa", "Suresh Vishwanath", "Yimo Han", "John Wright", "Sergei Rouvimov", "D Scott Katzer", "Neeraj Nepal", "Brian P Downey", "David A Muller", "Huili Grace Xing", "David J Meyer", "Debdeep Jena" ], "corpus_id": 4433991, "doc_id": "4433991", "n_citations": 64, "n_key_citations": 0, "score": 0, "title": "GaN/NbN epitaxial semiconductor/superconductor heterostructures", "venue": "Nature", "year": 2018 }, { "abstract": "The CH3NH3PbI3 (methylammonium lead triiodide) perovskite semiconductor system has been viewed as a blockbuster research material during the last five years. Because of its complicated architecture, several of its technological, physical and geometrical issues have been examined many times. Yet this has not assisted in overcoming a number of problems in the field nor in enabling the material to be marketed. For instance, these studies have not clarified the nature and type of hydrogen bonding and other noncovalent interactions involved; the origin of hysteresis; the actual role of the methylammonium cation; the nature of polarity associated with the tetragonal geometry; the unusual origin of various frontier orbital contributions to the conduction band minimum; the underlying phenomena of spin orbit coupling that causes significant bandgap reduction; and the nature of direct to indirect bandgap transition features. Arising from many recent reports, it is now a common belief that the I**H N interaction formed between the inorganic framework and the ammonium group of CH3NH3+ is the only hydrogen bonded interaction responsible for all temperature dependent geometrical polymorphs of the system, including the most stable one that persists at low temperatures, and the significance of all other noncovalent interactions has been overlooked. This study focussed only on the low temperature orthorhombic polymorph of CH3NH3PbI3 and CD3ND3PbI3, where D refers deuterium. Together with QTAIM, DORI and RDG based charge density analyses, the results of density functional theory calculations with PBE with and without van der Waals corrections demonstrate that the prevailing view of hydrogen bonding in CH3NH3PbI3 is misleading as it does not alone determine the a b+a tilting pattern of the PbI64 octahedra. This study suggests that it is not only the I**H/D N, but also the I**H/D C hydrogen/deuterium bonding and other noncovalent interactions (viz. tetrel pnictogen and lump hole bonding interactions) that are ubiquitous in the orthorhombic CH3NH3PbI3/CD3ND3PbI3 perovskite geometry. Their interplay determines the overall geometry of the polymorph, and are therefore responsible in part for the emergence of the functional optical properties of this material. This study also suggests that these interactions should not be regarded as the sole determinants of octahedral tilting since lattice dynamics is known to play a critical role as well, a common feature in many inorganic perovskites both in the presence and the absence of the encaged cation, as in CsPbI3/WO3 perovskites, for example.", "author_names": [ "Pradeep R Varadwaj", "Arpita Varadwaj", "Helder M Marques", "Koichi Yamashita" ], "corpus_id": 58004822, "doc_id": "58004822", "n_citations": 40, "n_key_citations": 0, "score": 0, "title": "Significance of hydrogen bonding and other noncovalent interactions in determining octahedral tilting in the CH3NH3PbI3 hybrid organic inorganic halide perovskite solar cell semiconductor", "venue": "Scientific Reports", "year": 2019 } ]

[ { "abstract": "A fundamental aim in the field of catalysis is the development of new modes of small molecule activation. One approach toward the catalytic activation of organic molecules that has received much attention recently is visible light photoredox catalysis. In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single electron transfer (SET) processes with organic substrates upon photoexcitation with visible light. Many of the most commonly employed visible light photocatalysts are polypyridyl complexes of ruthenium and iridium, and are typified by the complex tris(2,2' bipyridine) ruthenium(II) or Ru(bpy)32+ (Figure 1) These complexes absorb light in the visible region of the electromagnetic spectrum to give stable, long lived photoexcited states.1,2 The lifetime of the excited species is sufficiently long (1100 ns for Ru(bpy)32+ that it may engage in bimolecular electron transfer reactions in competition with deactivation pathways.3 Although these species are poor single electron oxidants and reductants in the ground state, excitation of an electron affords excited states that are very potent single electron transfer reagents. Importantly, the conversion of these bench stable, benign catalysts to redox active species upon irradiation with simple household lightbulbs represents a remarkably chemoselective trigger to induce unique and valuable catalytic processes. Figure 1 Ruthenium polypyridyl complexes: versatile visible light photocatalysts. The ability of Ru(bpy)32+ and related complexes to function as visible light photocatalysts has been recognized and extensively investigated for applications in inorganic and materials chemistry. In particular, photoredox catalysts have been utilized to accomplish the splitting of water into hydrogen and oxygen4 and the reduction of carbon dioxide to methane.5 Ru(bpy)32+ and its analogues have been used (i) as components of dye sensitized solar cells6 and organic light emitting diodes,7 (ii) to initiate polymerization reactions,8 and (iii) in photo dynamic therapy.9 Until recently, however, these complexes had been only sporadically employed as photocatalysts in the area of organic synthesis. The limited exploration of this area is perhaps surprising, as single electron, radical processes have long been employed in C C bond construction and often provide access to reactivity that is complementary to that of closed shell, two electron pathways.10 In 2008, concurrent reports from the Yoon group and our own lab detailed the use of Ru(bpy)32+ as a visible light photoredox catalyst to perform a [2 2] cycloaddition11 and an a alkylation of aldehydes,12 respectively. Shortly thereafter, Stephenson and co workers disclosed a photoredox reductive dehalogenation of activated alkyl halides mediated by the same catalyst.13 The combined efforts of these three research groups have helped to initiate a renewed interest in this field, prompting a diversity of studies into the utility of photoredox catalysis as a conceptually novel approach to synthetic organic reaction development. Much of the promise of visible light photoredox catalysis hinges on its ability to achieve unique, if not exotic bond constructions that are not possible using established protocols. For instance, photoredox catalysis may be employed to perform overall redox neutral reactions. As both oxidants and reductants may be transiently generated in the same reaction vessel, photoredox approaches may be used to develop reactions requiring both the donation and the reception of electrons at disparate points in the reaction mechanism. This approach stands in contrast to methods requiring stoichiometric chemical oxidants and reductants, which are often incompatible with each other, as well as to electrochemical approaches, which are not amenable to redox neutral transformations. Furthermore, single electron transfer events often provide access to radical ion intermediates having reactivity patterns fundamentally different from those of their ground electronic or excited states.14 Access to these intermediates using other means of activation is often challenging or requires conditions under which their unique reactivity cannot be productively harnessed. At the same time, photoredox catalysts such as Ru(bpy)32+ may also be employed to generate radicals for use in a diverse range of established radical chemistries. Photoredox reactions occur under extremely mild conditions, with most reactions proceeding at room temperature without the need for highly reactive radical initiators. The irradiation source is typically a commercial household light bulb, a significant advantage over the specialized equipment required for processes employing high energy ultraviolet (UV) light. Additionally, because organic molecules generally do not absorb visible light, there is little potential for deleterious side reactions that might arise from photoexcitation of the substrate itself. Finally, photoredox catalysts may be employed at very low loadings, with 1 mole or less being typical. This Review will highlight the early work on the use of transition metal complexes as photoredox catalysts to promote reactions of organic compounds (prior to 2008) as well as cover the surge of work that has appeared since 2008. We have for the most part grouped reactions according to whether the organic substrate undergoes reduction, oxidation, or a redox neutral reaction and throughout have sought to highlight the variety of reactive intermediates that may be accessed via this general reaction manifold.15 Studies on the use of transition metal complexes as visible light photocatalysts for organic synthesis have benefited tremendously from advances in the related fields of organic and semiconductor photocatalysis. Many organic molecules may function as visible light photocatalysts; analogous to metal complexes such as Ru(bpy)32+ organic dyes such as eosin Y, 9,10 dicyanoanthracene, and triphenylpyrylium salts absorb light in the visible region to give excited states capable of single electron transfer. These catalysts have been employed to achieve a vast range of bond forming reactions of broad utility in organic synthesis.16 Visible light photocatalysis has also been carried out with heterogeneous semiconductors such as mesoporous carbon nitride17 and various metal oxides and sulfides.18 These approaches are often complementary to photoredox catalysis with transition metal polypyridyl complexes, and we have referred to work in these areas when it is similar to the chemistry under discussion. However, an in depth discussion of the extensive literature in these fields is outside the scope of this Review, and readers are directed to existing reviews on these topics.16 18", "author_names": [ "Christopher K Prier", "Danica A Rankic", "David W C MacMillan" ], "corpus_id": 206897978, "doc_id": "206897978", "n_citations": 4145, "n_key_citations": 3, "score": 3, "title": "Visible light photoredox catalysis with transition metal complexes: applications in organic synthesis.", "venue": "Chemical reviews", "year": 2013 }, { "abstract": "More than 95% (in volume) of all of today's chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic research field. In this regard, metal organic frameworks (MOFs) offer great opportunities for the rational design of new catalytic solids, as highlighted by the unprecedented number of publications appearing over the past decade. In this review, the recent advances in the application of MOFs in heterogeneous catalysis are discussed. MOFs with intrinsic thermocatalytic activity, as hosts for the incorporation of metal nanoparticles, as precursors for the manufacture of composite catalysts and those active in photo and electrocatalytic processes are critically reviewed. The review is wrapped up with our personal view on future research directions.", "author_names": [ "Anastasiya Bavykina", "Nikita Kolobov", "Il Son Khan", "Jeremy A Bau", "Adrian Ramirez", "Jorge Gascon" ], "corpus_id": 214732268, "doc_id": "214732268", "n_citations": 195, "n_key_citations": 0, "score": 0, "title": "Metal Organic Frameworks in Heterogeneous Catalysis: Recent Progress, New Trends, and Future Perspectives.", "venue": "Chemical reviews", "year": 2020 }, { "abstract": "Organodiselenides are an important class of compounds characterized by the presence of two adjacent covalently bonded selenium nuclei. Among them, diaryldiselenides and their parent compound diphenyl diselenide attract continuing interest in chemistry as well as in close disciplines like medicinal chemistry, pharmacology and biochemistry. A search in SCOPUS database has revealed that in the last three years 105 papers have been published on the archetypal diphenyl diselenide and its use in organic catalysis and drug tests. The reactivity of the Se Se bond and the redox properties of selenium make diselenides efficient catalysts for numerous organic reactions, such as Bayer Villiger oxidations of aldehydes/ketones, epoxidations of alkenes, oxidations of alcohols and nitrogen containing compounds. In addition, organodiselenides might find application as mimics of glutathione peroxidase (GPx) a family of enzymes, which, besides performing other functions, regulate the peroxide tone in the cells and control the oxidative stress level. In this review, the essential synthetic and reactivity aspects of organoselenides are collected and rationalized using the results of accurate computational studies, which have been carried out mainly in the last two decades. The results obtained in silico provide a clear explanation of the anti oxidant activity of organodiselenides and more in general of their ability to reduce hydroperoxides. At the same time, they are useful to gain insight into some aspects of the enzymatic activity of the GPx, inspiring novel elements for rational catalyst and drug design.", "author_names": [ "Marco Dalla Tiezza", "Giovanni Ribaudo", "Laura Orian" ], "corpus_id": 105842982, "doc_id": "105842982", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Organodiselenides: Organic Catalysis and Drug Design Learning from Glutathione Peroxidase", "venue": "Current Organic Chemistry", "year": 2019 }, { "abstract": "", "author_names": [ "Benjamin List", "Oleg Grossmann" ], "corpus_id": 145984020, "doc_id": "145984020", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Cinchona Alkaloids in Organic Catalysis", "venue": "Synfacts", "year": 2019 }, { "abstract": "To meet the ever increasing global demand for energy, conversion of solar energy to chemical/thermal energy is very promising. Light mediated catalysis, including photocatalysis (organic transformations, water splitting, CO2 reduction, etc. and photothermal catalysis play key roles in solar to chemical/thermal energy conversion via the light matter interaction. The major challenges in traditional semiconductor photocatalysts include insufficient sunlight utilization, charge carrier recombination, limited exposure of active sites, and particularly the difficulty of understanding the structure activity relationship. Metal organic frameworks (MOFs) featuring semiconductor like behavior, have recently captured broad interest toward photocatalysis and photothermal catalysis because of their well defined and tailorable porous structures, high surface areas, etc. These advantages are beneficial for rational structural modulation for improved light harvesting and charge separation as well as other effects, greatly helping to address the aforementioned challenges and especially facilitating the establishment of the structure activity relationship. Therefore, it is increasingly important to summarize this research field and provide in depth insight into MOF based photocatalysis and photothermal catalysis to accelerate the future development. In this Account, we have summarized the recent advances in these two directly relevant applications, photocatalysis and photothermal catalysis, mainly focusing on the results in our lab. Given the unique structural features of MOFs, we have put an emphasis on rational material design to optimize the components and performance and to understand related mechanisms behind the enhanced activity. This Account starts by presenting an overview of solar energy conversion by catalysis. We explain why MOFs can be promising photocatalysts and exemplify the semiconductor like behavior of MOFs. More importantly, we show that MOFs provide a powerful platform to study photocatalysis, in which the involved three key processes, namely, light harvesting, electron hole separation, and surface redox reactions, can be rationally improved. Meanwhile, the structure activity relationship and charge separation dynamics are illustrated in this part. In addition, MOFs for photothermal catalysis have been introduced that are based on the photothermal effect of plasmonic metals and/or MOFs, together with light driven electronic state optimization of active sites, toward enhanced heterogeneous organic reactions. Finally, our brief outlooks on the current challenges and future development of MOF photocatalysis and photothermal catalysis are provided. It is believed that this Account will afford significant understanding and inspirations toward solar energy conversion over MOF based catalysts.", "author_names": [ "Juan-Ding Xiao", "Hai-Long Jiang" ], "corpus_id": 58611813, "doc_id": "58611813", "n_citations": 361, "n_key_citations": 0, "score": 0, "title": "Metal Organic Frameworks for Photocatalysis and Photothermal Catalysis.", "venue": "Accounts of chemical research", "year": 2019 }, { "abstract": "Metal organic frameworks (MOFs) have drawn wide attention as potential catalysts, offering high densities of catalytic sites in high area porous solids, some with stabilities at high temperatures. The field is at an early stage, characterized by numerous discoveries and novel demonstrations of catalytic properties associated with the crystalline structures of MOFs, but applications of MOFs as catalysts are still lacking. In this perspective we summarize advantages and limitations of MOFs as catalysts and fundamental issues to be addressed about their potential applications. MOF framework compositions and pore structures can strongly influence catalytic performance, allowing, for example, shape selective and bifunctional catalysis, but research is needed to quantify reaction/transport processes in MOFs, identify catalytic sites, and determine intrinsic catalytic reaction rates. Progress is hindered by the lack of understanding of the heterogeneity of MOFs, with catalytic sites sometimes being in structures.", "author_names": [ "D S Yang", "Bruce C Gates" ], "corpus_id": 104442800, "doc_id": "104442800", "n_citations": 249, "n_key_citations": 0, "score": 0, "title": "Catalysis by Metal Organic Frameworks: Perspective and Suggestions for Future Research", "venue": "", "year": 2019 }, { "abstract": "Abstract Metal organic frameworks (MOFs) also known as porous coordination polymers (PCPs) are a unique class of porous crystalline materials that are constructed by metal ions/clusters and organic ligands. The intriguing, numerous and tailorable structures as well as permanent porosity of MOFs make them very promising for a variety of potential applications, especially in catalysis. In this review, we systematically summarize the recent progress of MOF based materials (including pristine MOFs, MOF composites, and MOF derivatives) for heterogeneous catalysis, photocatalysis and electrocatalysis, according to the category of active site origin. We clearly indicate the significant strengths (and also weaknesses) of the MOF based materials, in reference to traditional catalysts, in catalytic studies. The challenges and opportunities in regard to the MOF based materials for catalysis have also been critically discussed.", "author_names": [ "Dandan Li", "Hai-Qun Xu", "Long Jiao", "Hailong Jiang" ], "corpus_id": 198475102, "doc_id": "198475102", "n_citations": 168, "n_key_citations": 0, "score": 0, "title": "Metal organic frameworks for catalysis: State of the art, challenges, and opportunities", "venue": "EnergyChem", "year": 2019 }, { "abstract": "", "author_names": [ "Benny K G Theng" ], "corpus_id": 217205855, "doc_id": "217205855", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Organic Catalysis by Clay Supported Reagents", "venue": "", "year": 2018 }, { "abstract": "Organic catalysis in ring opening polymerization (ROP) has become a powerful alternative to more traditional metal based catalysts. The field has developed to a point at which there are not only excellent low cost and easy to use organocatalysts for day to day polymerizations, but the ability to precisely control the synthesis of advanced polymer architectures and ROP monomers that are extremely challenging to polymerize with other catalysts now exists. This viewpoint article will highlight the key advances in organocatalyst design with the aim of encouraging the wider application of organic catalysts in ROP.", "author_names": [ "Andrew P Dove" ], "corpus_id": 96293620, "doc_id": "96293620", "n_citations": 299, "n_key_citations": 3, "score": 0, "title": "Organic Catalysis for Ring Opening Polymerization", "venue": "", "year": 2012 }, { "abstract": "Metal organic frameworks (MOFs) have emerged as a promising class of materials with several unique properties, such as high porosity, diverse composition, tunable pore structures, and versatile functionality. These characteristics enable MOFs to show potential in the field of heterogeneous catalysis. To satisfy the practical applications of MOFs, controllable integration of MOFs and functional materials (e.g. metal nanoparticles, quantum dots, polyoxometalates, molecular species, enzymes, silica, and polymers) can enhance the characteristics of MOFs through activity improvement and framework stabilization. In MOF composites/hybrids, functional materials can cooperatively work with MOFs to show enhanced catalytic activity, selectivity, and stability in a variety of chemical transformations. This review provides an overview of the significant advances in the development of diverse MOF composites/hybrids with special emphases on the preparation and catalytic applications.", "author_names": [ "Liyu Chen", "Qiang Xu" ], "corpus_id": 199159248, "doc_id": "199159248", "n_citations": 109, "n_key_citations": 0, "score": 0, "title": "Metal Organic Framework Composites for Catalysis", "venue": "Matter", "year": 2019 } ]

[ { "abstract": "Low signal to noise ratio (SNR) measurements, primarily due to the quartic attenuation of intensity with distance, are arguably the fundamental barrier to real time, high resolution, non line of sight (NLoS) imaging at long standoffs. To better model, characterize, and exploit these low SNR measurements, we use spectral estimation theory to derive a noise model for NLoS correlography. We use this model to develop a speckle correlation based technique for recovering occluded objects from indirect reflections. Then, using only synthetic data sampled from the proposed noise model, and without knowledge of the experimental scenes nor their geometry, we train a deep convolutional neural network to solve the noisy phase retrieval problem associated with correlography. We validate that the resulting deep inverse correlography approach is exceptionally robust to noise, far exceeding the capabilities of existing NLoS systems both in terms of spatial resolution achieved and in terms of total capture time. We use the proposed technique to demonstrate NLoS imaging with 300 um resolution at a 1 m standoff, using just two 1/8th {s}$s exposure length images from a standard complementary metal oxide semiconductor detector.", "author_names": [ "Christopher A Metzler", "Felix Heide", "Prasana Rangarajan", "Muralidhar Madabhushi Balaji", "Aparna I Viswanath", "Ashok Veeraraghavan", "Richard Baraniuk" ], "corpus_id": 210941820, "doc_id": "210941820", "n_citations": 45, "n_key_citations": 2, "score": 0, "title": "Deep inverse correlography: towards real time high resolution non line of sight imaging", "venue": "", "year": 2020 }, { "abstract": "The potential for improving the penetration depth of optical coherence tomography systems by using light sources with longer wavelengths has been known since the inception of the technique in the early 1990s. Nevertheless, the development of mid infrared optical coherence tomography has long been challenged by the maturity and fidelity of optical components in this spectral region, resulting in slow acquisition, low sensitivity, and poor axial resolution. In this work, a mid infrared spectral domain optical coherence tomography system operating at a central wavelength of 4 um and an axial resolution of 8.6 um is demonstrated. The system produces two dimensional cross sectional images in real time enabled by a high brightness 0.9 to 4.7 um mid infrared supercontinuum source with a pulse repetition rate of 1 MHz for illumination and broadband upconversion of more than 1 um bandwidth from 3.58 4.63 um to 820 865 nm, where a standard 800 nm spectrometer can be used for fast detection. The images produced by the mid infrared system are compared with those delivered by a state of the art ultra high resolution near infrared optical coherence tomography system operating at 1.3 mm, and the potential applications and samples suited for this technology are discussed. In doing so, the first practical mid infrared optical coherence tomography system is demonstrated, with immediate applications in real time non destructive testing for the inspection of defects and thickness measurements in samples that exhibit strong scattering at shorter wavelengths.Optical Coherence Tomography: Longer wavelengths improve imaging in depthUsing longer wavelengths of light in Optical Coherence Tomography (OCT) imaging allows deeper penetration in highly scattering materials, offering possibilities for OCT in non destructive testing and enhanced non invasive biomedical imaging. OCT images are based on interference patterns generated by combining light reflected from the examined object with reference light that does not encounter the object. It is currently most widely used to examine the retina of the eye. Researchers at the Technical University of Denmark, together with co workers in Austria and the UK, overcame several technical challenges to obtain images using mid infrared light to reveal microscopic structures that are not visible using conventional shorter wavelength near infrared light.The team combined broadband supercontinuum light and frequency upconversion to achieve high resolution and real time image acquisition.Promising applications include advances in defect detection and thickness measurements.", "author_names": [ "Niels Moller Israelsen", "Christian Rosenberg Petersen", "Ajanta Barh", "Deepak Jain", "Mikkel Jensen", "Gunther Hannesschlager", "Peter Tidemand-Lichtenberg", "Christian Pedersen", "Adrian Gh Podoleanu", "Ole Bang" ], "corpus_id": 53757683, "doc_id": "53757683", "n_citations": 106, "n_key_citations": 1, "score": 0, "title": "Real time high resolution mid infrared optical coherence tomography", "venue": "Light, science applications", "year": 2019 }, { "abstract": "We consider image transformation problems, where an input image is transformed into an output image. Recent methods for such problems typically train feed forward convolutional neural networks using a per pixel loss between the output and ground truth images. Parallel work has shown that high quality images can be generated by defining and optimizing perceptual loss functions based on high level features extracted from pretrained networks. We combine the benefits of both approaches, and propose the use of perceptual loss functions for training feed forward networks for image transformation tasks. We show results on image style transfer, where a feed forward network is trained to solve the optimization problem proposed by Gatys et al. in real time. Compared to the optimization based method, our network gives similar qualitative results but is three orders of magnitude faster. We also experiment with single image super resolution, where replacing a per pixel loss with a perceptual loss gives visually pleasing results.", "author_names": [ "Justin Johnson", "Alexandre Alahi", "Li Fei-Fei" ], "corpus_id": 980236, "doc_id": "980236", "n_citations": 5037, "n_key_citations": 464, "score": 0, "title": "Perceptual Losses for Real Time Style Transfer and Super Resolution", "venue": "ECCV", "year": 2016 }, { "abstract": "We introduce a real time, high resolution background replacement technique which operates at 30fps in 4K resolution, and 60fps for HD on a modern GPU. Our technique is based on background matting, where an additional frame of the background is captured and used in recovering the alpha matte and the foreground layer. The main challenge is to compute a high quality alpha matte, preserving strand level hair details, while processing high resolution images in real time. To achieve this goal, we employ two neural networks; a base network computes a low resolution result which is refined by a second network operating at high resolution on selective patches. We introduce two largescale video and image matting datasets: VideoMatte240K and PhotoMatte13K/85. Our approach yields higher quality results compared to the previous state of the art in background matting, while simultaneously yielding a dramatic boost in both speed and resolution.", "author_names": [ "Shanchuan Lin", "Andrey Ryabtsev", "Soumyadip Sengupta", "Brian Curless", "Steven M Seitz", "Ira Kemelmacher-Shlizerman" ], "corpus_id": 229156170, "doc_id": "229156170", "n_citations": 14, "n_key_citations": 4, "score": 1, "title": "Real Time High Resolution Background Matting", "venue": "CVPR", "year": 2021 }, { "abstract": "Fluorescence Imaging technology combined with a thin, linear response fluorescent plate and a camera was developed for real time 2D beam profiling of a raw beam of a high power laser in the wavelength range from blue to near infrared. The input laser beam was slightly absorbed on the fluorescent plate in front top of the profiler body and generated 2D fluorescence image, that was precise reproduction of the laser beam profile at the place, was reimaged by a camera at the back side of the profiler. The laser beam that transferred the fluorescent plate was separated by a dichroic mirror and outputted from the body. >99% energy of the input laser beam transferred the fluorescent plate, then the heat generation in the fluorescent plate was very low. This made long time, stable measurement of the high power, raw laser beam profile possible. >2MW/cm2 damage threshold of the fluorescent plate and the efficient heat management made direct measurement of >100W laser beam profiles possible without any attenuators and any computer aided image reconstructions. Speckle free and interference fringe free, high resolution images were also successfully obtained by the incoherent fluorescence reimaging.", "author_names": [ "Masaki Tsunekane", "K Sato", "Takehiro Takahashi", "S Yoshino", "N Yoshimori", "J Ohno" ], "corpus_id": 215724507, "doc_id": "215724507", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Direct, real time, high resolution beam profiler for high power laser", "venue": "LASE", "year": 2020 }, { "abstract": "", "author_names": [ "Florian Friess", "Christoph Muller", "Thomas Ertl" ], "corpus_id": 222143281, "doc_id": "222143281", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Real time High resolution Visualisation", "venue": "VMV", "year": 2020 }, { "abstract": "The recent appearance of augmented reality headsets, such as the Microsoft HoloLens, is a marked move from traditional 2D screen to 3D hologram like interfaces. Striving to be completely portable, these devices unfortunately suffer multiple limitations, such as the lack of real time, high quality depth data, which severely restricts their use as research tools. To mitigate this restriction, we provide a simple method to augment a HoloLens headset with much higher resolution depth data. To do so, we calibrate an external depth sensor connected to a computer stick that communicates with the HoloLens headset in real time. To show how this system could be useful to the research community, we present an implementation of small object detection on HoloLens device.", "author_names": [ "Mathieu Garon", "Pierre-Olivier Boulet", "Jean-Philippe Doironz", "Luc Beaulieu", "Jean-Francois Lalonde" ], "corpus_id": 164904, "doc_id": "164904", "n_citations": 58, "n_key_citations": 4, "score": 0, "title": "Real Time High Resolution 3D Data on the HoloLens", "venue": "2016 IEEE International Symposium on Mixed and Augmented Reality (ISMAR Adjunct)", "year": 2016 }, { "abstract": "Forensic hair evidence can be used to obtain retrospective timelines of drug use by analysis of hair segments. However, this is a laborious and time consuming process, and mass spectrometric (MS) imaging techniques, which show great potential for single hair targeted analysis, are less useful due to differences in hair growth rate between individual hairs. As an alternative, a fast untargeted analysis method was developed that uses direct analysis in real time high resolution mass spectrometry (DART HRMS) to longitudinally scan intact locks of hair without extensive sample preparation or segmentation. The hair scan method was validated for cocaine against an accredited liquid chromatography/tandem mass spectrometry (LC/MS/MS) method. The detection limit for cocaine in hair was found to comply with the cutoff value of 0.5 ng/mg recommended by the Society of Hair Testing; that is, the DART hair scan method is amenable to forensic cases. Under DART conditions, no significant thermal degradation of cocaine occurred. The standard DART spot size of 5.1 1.1 mm could be improved to 3.3 1.0 mm, corresponding to approximately 10 days of hair growth, by using a high spatial resolution exit cone. By use of data dependent product ion scans, multiple drugs of abuse could be detected in a single drug user hair scan with confirmation of identity by both exact mass and MS/HRMS fragmentation patterns. Furthermore, full scan high resolution data were retrospectively interrogated versus a list of more than 100 compounds and revealed additional hits and temporal profiles in good correlation with reported drug use.", "author_names": [ "Wilco F Duvivier", "Marc R van Putten", "Teris A van Beek", "Michel W F Nielen" ], "corpus_id": 22687799, "doc_id": "22687799", "n_citations": 21, "n_key_citations": 1, "score": 0, "title": "(Un)targeted Scanning of Locks of Hair for Drugs of Abuse by Direct Analysis in Real Time High Resolution Mass Spectrometry.", "venue": "Analytical chemistry", "year": 2016 }, { "abstract": "Conventional tools for measurement of laser spectra (e.g. optical spectrum analysers) capture data averaged over a considerable time period. However, the generation spectrum of many laser types may involve spectral dynamics whose relatively fast time scale is determined by their cavity round trip period, calling for instrumentation featuring both high temporal and spectral resolution. Such real time spectral characterisation becomes particularly challenging if the laser pulses are long, or they have continuous or quasi continuous wave radiation components. Here we combine optical heterodyning with a technique of spatio temporal intensity measurements that allows the characterisation of such complex sources. Fast, round trip resolved spectral dynamics of cavity based systems in real time are obtained, with temporal resolution of one cavity round trip and frequency resolution defined by its inverse (85 ns and 24 MHz respectively are demonstrated) We also show how under certain conditions for quasi continuous wave sources, the spectral resolution could be further increased by a factor of 100 by direct extraction of phase information from the heterodyned dynamics or by using double time scales within the spectrogram approach.", "author_names": [ "Srikanth Sugavanam", "Simon J Fabbri", "Son Thai Le", "Ivan A Lobach", "Sergey I Kablukov", "Serge Khorev", "Dmitry V Churkin" ], "corpus_id": 18757089, "doc_id": "18757089", "n_citations": 27, "n_key_citations": 1, "score": 0, "title": "Real time high resolution heterodyne based measurements of spectral dynamics in fibre lasers", "venue": "Scientific reports", "year": 2016 }, { "abstract": "We present a system for real time, high resolution, sparse voxelization of an image based surface model. Our approach consists of a coarse to fine voxel representation and a collection of parallel processing steps. Voxels are stored as a list of unsigned integer triples. An oracle kernel decides, for each voxel in parallel, whether to keep or cull its voxel from the list based on an image consistency criterion of its projection across cameras. After a prefix sum scan, kept voxels are subdivided and the process repeats until projected voxels are pixel size. These voxels are drawn to a render target and shaded as a weighted combination of their projections into a set of calibrated RGB images. We apply this technique to the problem of smooth visual hull reconstruction of human subjects based on a set of live image streams. We demonstrate that human upper body shapes can be reconstructed to giga voxel resolution at greater than 30 fps on modern graphics hardware.", "author_names": [ "Charles T Loop", "Cha Zhang", "Zhengyou Zhang" ], "corpus_id": 15769256, "doc_id": "15769256", "n_citations": 66, "n_key_citations": 1, "score": 0, "title": "Real time high resolution sparse voxelization with application to image based modeling", "venue": "HPG '13", "year": 2013 } ]

[ { "abstract": "Abstract This article focuses on chip scale single phase cooling for high heat flux and high temperature power device operation. This technology is focused on future wide band gap semiconductors, which are expected to survive harsh environments. To this end, strategies for near junction cooling of vertical current power electronics devices are briefly reviewed, and two chip scale coolers are experimentally investigated. Using single phase water at an inlet temperature of 50 degC, a 40 mm x 20 mm straight microchannel (quantity 200, 38 mm x 313 mm) cooling chip is shown to dissipate up to 127.5 W/cm2 over a 1 cm2 area with a pressure drop of 40.2 kPa at 100 ml/min. A second 75% downsized 20 mm x 10 mm cooling chip based on a unique 500 mm x 500 mm unit cell microchannel plus jet impingement array architecture is then introduced. At the same inlet temperature and in single phase operation, this chip scale cooler is shown to dissipate up to 1.02 kW/cm2 over a 0.25 cm2 area. A maximum average heat transfer coefficient of 120.2 kW/m2K and a pressure drop of 81.2 kPa is further established at a 450 ml/min fluid flow rate. The unit cell jet impingement based design is shown to additionally support average heater temperatures of 177.1 degC. Such technologies are anticipated to enable a 5 to 10 fold reduction in power package size when compared with traditional remote cooling strategies.", "author_names": [ "Feng Zhou", "Shailesh Joshi", "Yanghe Liu", "Ercan M Dede" ], "corpus_id": 202939638, "doc_id": "202939638", "n_citations": 7, "n_key_citations": 1, "score": 1, "title": "Near junction cooling for next generation power electronics", "venue": "International Communications in Heat and Mass Transfer", "year": 2019 }, { "abstract": "Rapid miniaturization alongwith increasing heat loads in power electronics devices like insulated gate bipolar transistors (IGBTs) have necessitated the need for advanced thermal management technologies in the packaging of these devices. This study quantifies the benefits of key advanced thermal management solutions for packaging of power electronics packages. Thermal resistance network modeling is used to estimate the maximum heat flux that can be dissipated by an IGBT package, while maintaining the junction temperature below 125 degC and 200 degC for silicon and silicon carbide (wide bandgap material) devices, respectively. While the model is completely analytical, it does address important complexities associated with heat flow in packages via the use of a sub model to account for thermal spreading. The advanced cooling technologies evaluated in this study include the use of high thermal conductivity polymer heat sinks, double sided heat sinking of packages, liquid cooling (single and two phase) jet impingement and spray cooling. Additionally, combinations of these cooling technologies are evaluated as well. The heat dissipation achievable from these technologies is compared with that from an air cooled copper heat sink (baseline) The results of this study provide insights and a starting point for selecting thermal management technologies (or combinations) based on the heat dissipation requirements of power electronics packages.", "author_names": [ "Palash V Acharya", "Vaibhav Bahadur", "Robert E Hebner", "Abdelhamid Ouroua", "Shannon Strank" ], "corpus_id": 214251649, "doc_id": "214251649", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Assessing the Performance of Advanced Cooling Techniques on Thermal Management of Next Generation Power Electronics", "venue": "ASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems", "year": 2019 }, { "abstract": "", "author_names": [ "Palash V Acharya" ], "corpus_id": 216532266, "doc_id": "216532266", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Assessing polymeric nanocomposites and advanced cooling techniques for thermal management of next generation power electronics", "venue": "", "year": 2019 }, { "abstract": "Abstract Large transverse output voltage of transverse thermoelectric film devices is key for their important applications. Currently, the transverse output voltage is only several to tens of mV*K 1 due to the great challenge that multilayer films with a nanometer scale thickness are tilted in transverse thermoelectric film devices. Herein, a novel misaligned mask method is developed to low costly fabricate artificially tilted thermoelectric film devices (ATTFDs) with excellent transverse power generation and cooling performances through accurately controlling the tilted arrangement of nanometer scale multilayer films. The huge transverse output voltage of 300 mV K 1 and cooling temperature gradient of 68 K*mm 1 are obtained for the first time in Bi/Bi0.5Sb1.5Te3 ATTFDs, which are comparable to those from expensive superlattice based thermoelectric devices. Our work demonstrates that ATTFDs can be narrow space applied to high efficient film refrigerators in next generation electronics and optoelectronics, high sensitive thermal response sensors, thermoelectric driven inorganic LED film devices.", "author_names": [ "Xin Mu", "Wanting Zhu", "Wenyu Zhao", "Hongyu Zhou", "Zhigang Sun", "Cuncheng Li", "Shifang Ma", "Ping Wei", "Xiaolei Nie", "Jihui Yang", "Qingjie Zhang" ], "corpus_id": 210512063, "doc_id": "210512063", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Excellent transverse power generation and cooling performances of artificially tilted thermoelectric film devices", "venue": "", "year": 2019 }, { "abstract": "An innovative arrangement for the electrothermal integration of power electronics and motor in a high power drive systems is presented within this paper with a focus on automotive traction applications. Important challenges which needed to be overcome within this research work consist firstly of the coupling of the thermal design of the switching power modules and of the permanent magnet (PM) electric motor and secondly, the integration of high speed switching devices into the motor housing, without compromising the performance of the transistors. To provide a solution to these challenges, an integrated liquid cooling system for both the stator windings and the power devices has been designed. A bespoke power module has been designed and manufactured in order to meet the specific requirements of this packaging approach. The control structure of the drive system is also highlighted together with initial commissioning results.", "author_names": [ "Liliana de Lillo", "Behzad Ahmadi", "Lee Empringham", "Mark Johnson", "Jordi Espina", "Robert Abebe" ], "corpus_id": 54454572, "doc_id": "54454572", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Next Generation Integrated Drive, NGID: A Novel Approach to Thermal and Electrical Integration of High Power Density Drives in Automotive Applications", "venue": "2018 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2018 }, { "abstract": "This thesis sets out a series of new techniques to improve the thermal management of power electronics. The work is motivated by the increasing impetus to design smaller, more energy efficient electronic power systems for a range of applications, notably electric vehicles. Thermal management is an increasingly important tool which can facilitate improvements in power density through better monitoring and control of system temperatures. This thesis seeks to deliver improvements in implementing this strategy. A review of the state of the art in thermal management is reported, focussing on temperature measurement, thermal characterisation and system modelling techniques. In addition, novel techniques for arbitrary dissipation control and die temperature measurements in semiconductor devices are presented. A novel analysis of the limitations of low order thermal models is also described. Improvements and applications of these techniques form the basis of this thesis. The pseudorandom binary sequence (PRBS) technique for system identification is applied throughout the thesis to characterise thermal systems. A mathematical analysis is provided, together with a novel technique to determine the minimum gain which can be identified by PRBS techniques in the presence of noise. A novel improvement to the PRBS technique for typically ten times more noise resilient measurements is then developed based on mathematical mixing of different frequency PRBS signals. In parallel, a novel technique is formulated to estimate the temperature throughout a multiple device system using digital IIR filters and PRBS thermal characterisation, which achieves errors of 3 5% when demonstrated practically. By combining these techniques, a comprehensive temperature estimation and control methodology is implemented for a multiple device system under active cooling. Finally, the expansion of the proposed methodologies to steady state die temperature estimation is presented with comparable accuracy to surface temperature measurements, increasing the usefulness of the developed techniques in a practical setting.", "author_names": [ "Jonathan N Davidson" ], "corpus_id": 106616077, "doc_id": "106616077", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Advanced thermal modelling and management techniques to improve power density in next generation power electronics", "venue": "", "year": 2015 }, { "abstract": "Abstract The global tendency towards miniaturization driven by the micro electronics industry is pushing system density and packaging towards unprecedented values of thermal design power, with a dramatic reduction of the surface area of the devices.As such, the thermal management of these systems requires novel and smarter cooling methods, in particular in view of the next generation of 3D integrated circuits.On chip two phase cooling represents a very attractive long term solution to this problem.Two phase flow boiling in a micro pin fin heat sink is experimentally studied here for this cooling process.The micro evaporator tested has a heated area of 1 cm 2 consisting of 66 rows of cylindrical in line micro pin fins with a diameter, height and pitch of respectively 50 m m, 100 m m and 91.7 m m .An infrared temperature measurement technique is coupled with high speed flow visualization to investigate the fluid dynamics and heat transfer associated with flow boiling in the micro evaporator.Time dependent features of the flow, operational maps, pressure drop and heat transfer performance in stable flow conditions under a range of heat flux and mass flux of, respectively, 20 44 W cm 2 and 750 1750 kg m 2 s 1 and a constant outlet saturation temperature of 25 deg C are experimentally investigated.The fluid used is the dielectric refrigerant R134a.This study shows that R134a exhibits a very stable flow boiling behavior under a wide range of flow conditions.Low amplitude temperature oscillations with frequencies in the range of 14 22 Hz are detected and the high speed videos demonstrate that these are related to the bubble nucleation process.The heat transfer coefficient trends along the test section are strongly dependent on the vapor quality, with local values as high as 50 kW m 2 K 1 measured in the proximity of the flow area exit. This dependency is attributed to the impact of the two phase flow patterns which develop along the channels, i.e. slug and annular flow. The heat transfer performance enhances significantly with the applied heat, while mass flux exhibits a minor influence.", "author_names": [ "Chiara Falsetti", "Mirco Magnini", "John Richard Thome" ], "corpus_id": 115353539, "doc_id": "115353539", "n_citations": 18, "n_key_citations": 2, "score": 0, "title": "Hydrodynamic and thermal analysis of a micro pin fin evaporator for on chip two phase cooling of high density power micro electronics", "venue": "", "year": 2018 }, { "abstract": "The paper will discuss the integration of 3D printing and inkjet printing fabrication technologies for microwave and millimeter wave applications. With the recent advancements in 3D and inkjet printing technology, achieving resolution down to 50 um, it is feasible to fabricate electronic components and antennas operating in the millimeter wave regime. The nature of additive manufacturing allows designers to create custom components and devices for specialized applications and provides an excellent and inexpensive way of prototyping electronic designs. The combination of multiple printable materials enables the vertical integration of conductive, dielectric, and semi conductive materials which are the fundamental components of passive and active circuit elements such as inductors, capacitors, diodes, and transistors. Also, the on demand manner of printing can eliminate the use of subtractive fabrication processes, which are necessary for conventional microfabrication processes such as photolithography, and drastically reduce the cost and material waste of fabrication. The utilization of 3D and inkjet printing to fabricate integrated circuits interconnects and antennas is an interesting avenue for research due to the customized nature of certain applications such as automotive radar and 5G wireless solutions. This paper will explore different ways of interfacing with monolithic microwave integrated circuits (MMICs) using additive manufacturing methods including printed vias, ramp interconnects, and wire bonds. With these structures, microwave properties such as matching and losses can be improved due to the ease of printing tailored interfaces that match with each individual device. It will also include demonstration of fully additively manufactured antennas exhibiting excellent bandwidth and circular polarization, something that is expensive and difficult to achieve with traditional manufacturing methods. Finally, the paper will also introduce future directions for additively manufactured electronics, including the packaging of high power devices, cooling functionality, and using exotic materials for electromagnetic interference shielding and flexibility. INTRODUCTION Additive manufacturing has been gaining a lot of traction in the past decade as it promises very fast prototyping and low cost manufacturing. Components that typically have month long lead times can be fabricated in mere days or even hours. Every year, additional 3D printable materials are being introduced to the market, and with that 3D printing can be utilized for new applications. One area of additive manufacturing is inkjet printing, which is a drop on demand method of printing large areas of devices with high accuracy, where metal, dielectric and semiconducting inks can be deposited quickly on almost all surfaces. Inkjet printing is extremely fast and low cost and can be utilized for applications at mm wave frequencies allowing for fast prototyping and roll to roll manufacturing [1] Additionally, the drop on demand nature of inkjet printing facilitates a low temperature <200C) process as the metal is directly deposited on top of the substrate instead of using high temperature PVD systems. With this, flexible substrates are easily metallized without any bending or warping. Another area of additive manufacturing is 3D printing. 3D printers utilize a 3D model and a slicer to slice the model into very thin layers and recreates the model using these layers. Traditionally 3D prints were fabricated using fused deposition model (FDM) where a polymer filament, usually PLA or ABS plastics, was melted and extruded to make the model layer by layer. However new stereolithography (SLA) systems, where the model is built onto a platform in a photoactive resin bath, are generally able to achieve very high (10um) resolution print layers. Another big benefit of SLA printing is its surface roughness, which is on the order of hundreds of nanometers [2] These two factors allow for 3D SLA printed parts to be utilized in high frequency mm wave applications. This paper will delve into several topics in high frequency designs using both 3D and inkjet printing. Designs for fully inkjet printed RF passive components such as capacitors and inductors will be presented. These devices are critical to RF systems and are used in various ways including impedance matching and DC/RF chokes. These devices can be easily manufactured in the same process, in the same inkjet printer, saving time and cost. Other passive devices such as die interconnects will be discussed. These fully additive manufactured interconnects, which replaces wire bonding, are a revolutionary way of designing smart packaging, the inclusion of many different functionality in one smart package. Next advanced 3D printed antennas are presented. These specific antennas demonstrate complex structures that are difficult or impossible to fabricate using traditional manufacturing techniques and drastically reduce the time of prototype to production. These antennas introduce advantageous features, such as high bandwidth or ease of integration with other components. Finally, the paper will explore future topics for research. INKJET PRINTED PASSIVE COMPONENTS Typically, in an RF system, baluns, capacitors and inductors are utilized as in signal conditioning, impedance matching, coupling/choking applications. These devices are critical to RF applications and should have low loss and high quality (Q) factor. Typically, lumped components in standard surface mount packages, such as 0603, are placed and soldered onto circuit boards. However, these packages are tall and bulky and can snap off when bent on flexible substrates. Inkjet printed capacitors and inductors are planar structures, conformal, and low loss which can withstand bending when printed on flexible substrates such as LCP. Additionally, components which generally take many fabrication steps, such as metallization and dielectric deposition can be completed in one inkjet printing process. The additive, drop on demand aspect of fabrication is also low waste, which can save drastic costs when printing in massive quantities. Metal Insulator Metal Capacitors Metal insulator metal (MIM) capacitors are the most basic single layer capacitors. These capacitors are two metal electrodes separated by a dielectric, both of which can be inkjet printable. For metal conductive layers, silver nano particle (SNP) was printed and for dielectric insulator layers, polyvinylpyrrolidone(PVP) was printed for thin films >0.5m) or production epoxy based negative photo resist for thick films(>3m) These allow for various controls of capacitance values, as printing thicker or thinner dielectrics or changing the electrode area, granting full control of design specifications based on the end application. Flexible MIM capacitors fabricated on polyimide substrates show self resonance frequency(SRF) of >1GHz[3] while MIM capacitors with 1.6m 1.8m thick PVP dielectric and SNP metal electrodes were fabricated on silicon substrate as shown in Fig.1 has SRF of 1.2GHz, a maximum Q factor of 25, with a capacitance per area of 33pF/mm [4] Fig. 1. Inkjet printed MIM capacitors on silicon wafers Baluns and Inductors Inductors and baluns are similar spiral structures. Baluns are usually used in signal conditioning applications to change balanced signals into unbalanced and vice versa. Transformer based baluns incorporate three windings in 5 layer structures as shown in Fig. 2a and b respectively [5] The transformer balun demonstrates the complex structures that can be fabricated using additive inkjet printing. Inductors have a similar winding structure since they require long conductive traces to get appreciable inductance values. 1.5 turn inductors were fabricated with SNP ink as the conductive metal and epoxy based negative photo resist ink as the dielectric layer separators and shows a Q factor of 21 at 1 GHz [6] Both applications are inherently multilayer structures, but these demonstrations show the ease of inkjet printing multilayer RF components which can operate at high frequencies and the level of integration that can be achieved by utilizing inkjet printing to reduce processing steps. Fig 2. Inkjet printed 5 layer RF balun schematic (a) and fabricated sample on LCP (b) (a) (b) INTERCONNECTS Interconnects are essential packaging components for the practical implementation of any microelectronic device in a functional electronic system. Specifically, first level interconnects are responsible for interconnecting a microelectronic chip, or die, with its packaging substrate. In a modern wireless system, this packaging substrate can take the form of a metallic leadframe for traditionally packaged off the shelf components, a laminate based interposer for signal fanout and redistribution, or a printed circuit board (PCB) where a chip is integrated directly with other packaged components on the primary host substrate. These packaging methods typically achieve first level interconnection through bond wire or flip chip technologies depending on several design factors, including signal pad location, thermal path management, and the routing of signals below an interconnected device. Wire and ribbon bonding are rapid, low cost, and mature methods for realizing these chip to board interconnects, however increased parasitics and mechanical stability are highlighted concerns that must be considered in a practical setting [7] With the recent growth of additive manufacturing technologies for the development of wireless components, packages, and systems, the first level interconnect is a prime candidate for investigating the integration of inkjet and 3D printing fabrication methods to realize fully printed 3D RF interconnect transitions. The use of additive manufacturing technologies for the interconnection process has the potential to offer several improvements from traditional wire bonding soluti", "author_names": [ "Xuanke He", "Bijan Tehrani", "Ryan A Bahr", "Manos M Tentzeris" ], "corpus_id": 198951933, "doc_id": "198951933", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Additive Manufacturing for Next Generation Microwave Electronics and Antennas", "venue": "", "year": 2019 }, { "abstract": "The objective of this research was to investigate the performance of two phase spray cooling with HFC 134a and HFO 1234yf refrigerants using practical enhanced heat transfer surfaces. Results of the study were expected to provide a quantitative spray cooling performance comparison with working fluids representing the current and next generation mobile air conditioning refrigerants, and demonstrate the feasibility of this approach as an alternative active cooling technology for the thermal management of high heat flux power electronics (i.e. IGBTs) in electric drive vehicles. Potential benefits of two phase spray cooling include achieving more efficient and reliable operation, as well as compact and lightweight system design that would lead to cost reduction. The experimental work involved testing of four different enhanced boiling surfaces in comparison to a plain reference surface, using a commercial pressure atomizing spray nozzle at a range of liquid flow rates for each refrigerant to determine the spray cooling performance with respect to heat transfer coefficient (HTC) and critical heat flux (CHF) The heater surfaces were prepared using dual stage electroplating, brush coating, sanding, and particle blasting, all featuring \"practical\" room temperature processes that do not require specialized equipment. Based on the obtained results, HFC 134a provided a better heat transfer performance through higher HTC and CHF values compared to HFO 1234yf at all tested surfaces and flow rates. While majority of the tested surfaces provided comparable HTC and modestly higher CHF values compared to the reference surface, one of the enhanced surfaces offered significant heat transfer enhancement.", "author_names": [ "Sulaiman Saleh Altalidi" ], "corpus_id": 195564977, "doc_id": "195564977", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Two Phase Spray Cooling with HFC 134a and HFO 1234yf for Thermal Management of Automotive Power Electronics using Practical Enhanced Surfaces", "venue": "", "year": 2017 }, { "abstract": "The aircraft industry demands a significant increase in terms of efficiency and gravimetric power density of power converters for next generation aerospace applications. Between the two minimum targets, i.e. an efficiency 98% and a gravimetric power density 10 kW/kg, the specification concerning the converter weight is the most challenging to fulfill. Since cooling systems and magnetic components dominate the weight breakdown of conventional converter concepts, multi cell topologies, enabling improved semiconductors performance and reduced filtering requirements, are foreseen as promising solutions for the power electronics on board of More Electric Aircraft. On the other hand, the necessary simultaneous operation of a high number of cells inevitably limits the reliability of multi cell converters if redundancy is not provided. In this paper, a favorable scaling trend of power density with respect to reliability, aiming to guarantee fault tolerant operation without affecting the performance figures, is identified in modular multi cell converters. Thus, a 45 kW weight optimized modular multi cell three phase inverter featuring a redundant power stage is optimized, achieving an efficiency of 99% and a gravimetric power density of 22.8 kW/kg.", "author_names": [ "Mattia Guacci", "Dominik Bortis", "Johann Walter Kolar" ], "corpus_id": 54454648, "doc_id": "54454648", "n_citations": 10, "n_key_citations": 2, "score": 0, "title": "High Efficiency Weight Optimized Fault Tolerant Modular Multi Cell Three Phase GaN Inverter for Next Generation Aerospace Applications", "venue": "2018 IEEE Energy Conversion Congress and Exposition (ECCE)", "year": 2018 } ]

[ { "abstract": "Abstract A large variety of electrochemical advanced oxidation processes (EAOPs) have been recently developed to remove organic pollutants from wastewaters to avoid their serious health risk factors from their environmental accumulation and to reuse the treated water for human activities. The effectiveness of EAOPs is based on the in situ production of strong reactive oxygen species (ROS) like hydroxyl radical OH) Photoelectrocatalysis (PEC) has emerged as a promising powerful EAOP by combining photocatalytic and electrolytic processes. It consists in the promotion of electrons from the valence band to the conduction band of a semiconductor photocatalyst upon light irradiation, with production of positive holes. The fast recombination of the electron/hole pairs formed is avoided in PEC by applying an external bias potential to the photocatalyst that extracts the photogenerated electrons up to the cathode of the electrolytic cell. Organics can be oxidized directly by the holes, *OH formed from water oxidation with holes and other ROS produced between the electrons and dissolved O2. This paper presents a general and critical review on the application of PEC to the remediation of wastewaters with organic pollutants. Special attention is made over the different kinds of photocatalysts utilized and preparation methods of the most ubiquitous TiO2 materials. Typical PEC systems and main operation variables that affect the effectiveness of the degradation process are also examined. An exhaustive analysis of the advances obtained on the treatment of dyes, chemicals and pharmaceuticals from synthetic solutions, as well as of real wastewaters, is performed. Finally, research prospects are proposed for the future development of PEC with perspectives to industrial application.", "author_names": [ "Sergi Garcia-Segura", "Enric Brillas" ], "corpus_id": 99673254, "doc_id": "99673254", "n_citations": 338, "n_key_citations": 4, "score": 0, "title": "Applied photoelectrocatalysis on the degradation of organic pollutants in wastewaters", "venue": "", "year": 2017 }, { "abstract": "To meet the ever increasing global demand for energy, conversion of solar energy to chemical/thermal energy is very promising. Light mediated catalysis, including photocatalysis (organic transformations, water splitting, CO2 reduction, etc. and photothermal catalysis play key roles in solar to chemical/thermal energy conversion via the light matter interaction. The major challenges in traditional semiconductor photocatalysts include insufficient sunlight utilization, charge carrier recombination, limited exposure of active sites, and particularly the difficulty of understanding the structure activity relationship. Metal organic frameworks (MOFs) featuring semiconductor like behavior, have recently captured broad interest toward photocatalysis and photothermal catalysis because of their well defined and tailorable porous structures, high surface areas, etc. These advantages are beneficial for rational structural modulation for improved light harvesting and charge separation as well as other effects, greatly helping to address the aforementioned challenges and especially facilitating the establishment of the structure activity relationship. Therefore, it is increasingly important to summarize this research field and provide in depth insight into MOF based photocatalysis and photothermal catalysis to accelerate the future development. In this Account, we have summarized the recent advances in these two directly relevant applications, photocatalysis and photothermal catalysis, mainly focusing on the results in our lab. Given the unique structural features of MOFs, we have put an emphasis on rational material design to optimize the components and performance and to understand related mechanisms behind the enhanced activity. This Account starts by presenting an overview of solar energy conversion by catalysis. We explain why MOFs can be promising photocatalysts and exemplify the semiconductor like behavior of MOFs. More importantly, we show that MOFs provide a powerful platform to study photocatalysis, in which the involved three key processes, namely, light harvesting, electron hole separation, and surface redox reactions, can be rationally improved. Meanwhile, the structure activity relationship and charge separation dynamics are illustrated in this part. In addition, MOFs for photothermal catalysis have been introduced that are based on the photothermal effect of plasmonic metals and/or MOFs, together with light driven electronic state optimization of active sites, toward enhanced heterogeneous organic reactions. Finally, our brief outlooks on the current challenges and future development of MOF photocatalysis and photothermal catalysis are provided. It is believed that this Account will afford significant understanding and inspirations toward solar energy conversion over MOF based catalysts.", "author_names": [ "Juan-Ding Xiao", "Hai-Long Jiang" ], "corpus_id": 58611813, "doc_id": "58611813", "n_citations": 361, "n_key_citations": 0, "score": 1, "title": "Metal Organic Frameworks for Photocatalysis and Photothermal Catalysis.", "venue": "Accounts of chemical research", "year": 2019 }, { "abstract": "Semiconductor polymeric graphitic carbon nitride (g C3N4) photocatalysts have attracted dramatically growing attention in the field of the visible light induced hydrogen evolution reaction (HER) because of their facile synthesis, easy functionalization, attractive electronic band structure, high physicochemical stability and photocatalytic activity. This review article presents a panorama of the latest advancements in the rational design and development of g C3N4 and g C3N4 based composite photocatalysts for HER application. Concretely, the review starts with the development history, synthetic strategy, electronic structure and physicochemical characteristics of g C3N4 materials, followed by the rational design and engineering of various nanostructured g C3N4 (e.g. thinner, highly crystalline, doped, and porous g C3N4) photocatalysts for HER application. Then a series of highly efficient g C3N4 (e.g. metal/g C3N4, semiconductor/g C3N4, metal organic framework/g C3N4, carbon/g C3N4, conducting polymer/g C3N4, sensitizer/g C3N4) composite photocatalysts are exemplified. Lastly, this review provides a comprehensive summary and outlook on the major challenges, opportunities, and inspiring perspectives for future research in this hot area on the basis of pioneering works. It is believed that the emerging g C3N4 based photocatalysts will act as the \"holy grail\" for highly efficient photocatalytic HER under visible light irradiation.", "author_names": [ "Guangfu Liao", "Yan Gong", "Li Zhang", "Haiyang Gao", "Guan-Jun Yang", "Baizeng Fang" ], "corpus_id": 149686925, "doc_id": "149686925", "n_citations": 307, "n_key_citations": 0, "score": 0, "title": "Semiconductor polymeric graphitic carbon nitride photocatalysts: the \"holy grail\" for the photocatalytic hydrogen evolution reaction under visible light", "venue": "", "year": 2019 }, { "abstract": "Organic semiconductors have attracted a lot of attention since the discovery of highly doped conductive polymers, due to the potential application in field effect transistors (OFETs) light emitting diodes (OLEDs) and photovoltaic cells (OPVs) Single crystals of organic semiconductors are particularly intriguing because they are free of grain boundaries and have long range periodic order as well as minimal traps and defects. Hence, organic semiconductor crystals provide a powerful tool for revealing the intrinsic properties, examining the structure property relationships, demonstrating the important factors for high performance devices and uncovering fundamental physics in organic semiconductors. This review provides a comprehensive overview of the molecular packing, morphology and charge transport features of organic semiconductor crystals, the control of crystallization for achieving high quality crystals and the device physics in the three main applications. We hope that this comprehensive summary can give a clear picture of the state of art status and guide future work in this area.", "author_names": [ "Chengliang Wang", "Huanli Dong", "Lang Jiang", "Wenping Hu" ], "corpus_id": 206086999, "doc_id": "206086999", "n_citations": 283, "n_key_citations": 2, "score": 0, "title": "Organic semiconductor crystals.", "venue": "Chemical Society reviews", "year": 2018 }, { "abstract": "Abstract Graphitic carbon nitride (g C3N4) as a fascinating visible light active semiconductor photocatalyst has medium band gap, non toxic nature, stable chemical structure and high thermal stability. Recently, intensive researches are focused on photocatalytic activity of g C3N4 for wastewater treatment. This review demonstrates latest progress in fabrication of graphitic carbon nitride C3N4 incorporated nanocomposite to explore photocatalytic ability for water purification. The g C3N4 based nanocomposites were categorized as g C3N4 metal free nanocomposite, noble metals/g C3N4 heterojunction, non metal doped g C3N4, transition and post transition metal based g C3N4 nanocomposite. Apart from fabrication methods, we emphasized on elaborating the mechanism of activity enhancement during photocatalytic process.", "author_names": [ "Anita Sudhaik", "Pankaj Raizada", "Pooja Shandilya", "Dae-Yong Jeong", "Ji-Ho Lim", "Pardeep Singh" ], "corpus_id": 104928184, "doc_id": "104928184", "n_citations": 154, "n_key_citations": 1, "score": 0, "title": "Review on fabrication of graphitic carbon nitride based efficient nanocomposites for photodegradation of aqueous phase organic pollutants", "venue": "", "year": 2018 }, { "abstract": "Organic semiconducting single crystals (OSSCs) are ideal candidates for the construction of high performance optoelectronic devices/circuits and a great platform for fundamental research due to their long range order, absence of grain boundaries, and extremely low defect density. Impressive improvements have recently been made in organic optoelectronics: the charge carrier mobility is now over 10 cm2 V 1 s 1 and the fluorescence efficiency reaches 90% for many OSSCs. Moreover, high mobility and strong emission can be integrated into a single OSSC, for example, showing a mobility of up to 34 cm2 V 1 s 1 and a photoluminescence yield of 41.2% These achievements are attributed to the rational design and synthesis of organic semiconductors as well as improvements in preparation technology for crystals, which accelerate the application of OSSCs in devices and circuits, such as organic field effect transistors, organic photodetectors, organic photovoltaics, organic light emitting diodes, organic light emitting transistors, and even electrically pumped organic lasers. In this context, an overview of these fantastic advancements in terms of the fundamental insights into developing high performance organic semiconductors, efficient strategies for yielding desirable high quality OSSCs, and their applications in optoelectronic devices and circuits is presented. Finally, an overview of the development of OSSCs along with current challenges and future research directions is provided.", "author_names": [ "Xiaotao Zhang", "Huanli Dong", "Wenping Hu" ], "corpus_id": 51710892, "doc_id": "51710892", "n_citations": 153, "n_key_citations": 0, "score": 0, "title": "Organic Semiconductor Single Crystals for Electronics and Photonics.", "venue": "Advanced materials", "year": 2018 }, { "abstract": "Abstract Semiconductor photocatalyst mediated advanced oxidation processes are regarded as one of the most efficient technologies to mitigate organic pollutants in water. However, poor activity under visible light and the recombination of photogenerated electron and hole pairs hinder large scale applicability of semiconductor photocatalysts for water purification. The modification of semiconductor photocatalysts with carbon quantum dots (CQDs) is of high importance due to low toxicity, aqueous stability, enhanced surface area, economic feasibility, good biocompatibility and chemical inertness of CQDs. In this review, we highlight strategies to improve the activity of conventional semiconductor photocatalysts via coupling with CQDs. The enhanced photocatalytic activity of CQD modified narrow and wide band gap photocatalysts is due mainly to up conversion photoluminescence (UPCL) and the electron reservoir properties of CQDs, while in the case of Z scheme photocatalysts CQDs act as an electron mediator. Finally, a conclusive outlook and suggested research directions are provided to address challenges such as the inadequate separation of photoinduced charge carriers.", "author_names": [ "Sheetal Sharma", "Vishal Dutta", "Pardeep Singh", "Pankaj Raizada", "Abolfazl Rahmani-Sani", "Ahmad Hosseini-Bandegharaei", "Vijay Kumar Thakur" ], "corpus_id": 159429540, "doc_id": "159429540", "n_citations": 134, "n_key_citations": 0, "score": 0, "title": "Carbon quantum dot supported semiconductor photocatalysts for efficient degradation of organic pollutants in water: A review", "venue": "Journal of Cleaner Production", "year": 2019 }, { "abstract": "Metal organic frameworks (MOFs) with low density, high porosity, and easy tunability of functionality and structural properties, represent potential candidates for use as semiconductor materials. The rapid development of the semiconductor industry and the continuous miniaturization of feature sizes of integrated circuits toward the nanometer (nm) scale require novel semiconductor materials instead of traditional materials like silicon, germanium, and gallium arsenide etc. MOFs with advantageous properties of both the inorganic and the organic components promise to serve as the next generation of semiconductor materials for the microelectronics industry with the potential to be extremely stable, cheap, and mechanically flexible. Here, a perspective of recent research is provided, regarding the semiconducting properties of MOFs, bandgap studies, and their potential in microelectronic devices.", "author_names": [ "Muhammad Usman", "Shruti Mendiratta", "Kuang-Lieh Lu" ], "corpus_id": 205274755, "doc_id": "205274755", "n_citations": 122, "n_key_citations": 0, "score": 0, "title": "Semiconductor Metal Organic Frameworks: Future Low Bandgap Materials.", "venue": "Advanced materials", "year": 2017 }, { "abstract": "Abstract Organic pollutants' treatment in wastewater has attracted extensive attention due to its degradation resistance and potentially hazardous to human health. Some organic matters such as persistent organic pollutants (POPs) could exist in environment and resist to decomposition, which may cause chronic intoxication or even cancers. Because photocatalytic technique is efficient, nontoxic, and cost effective to degrade organic pollutants, some semiconductors including TiO2 and ZnO as photocatalysts have aroused wide public concern. CeO2 has been reported as an efficient photocatalyst in contrast to TiO2 owing to its high oxygen storage, eco friendly properties and photostability. But inefficient utilization of solar energy due to its intrinsic wide bandgap restrains its further application in real environmental pollutant treatment. In order to improve photocatalytic performances of CeO2, some modifications have been developed such as doping ions, coupling with semiconductor and construction of CeO2 based solid solution. The purpose of this review is to introduce these techniques, reveals its fundamental mechanisms and the recent researches about photodegradation of organic pollutants in wastewater over CeO2 based photocatalysts. Besides, this review will evaluate the photocatalytic performance for organic pollutants and outlook the challenges and prospects in the future.", "author_names": [ "Ran Ma", "Sai Zhang", "Tao Wen", "Pengcheng Gu", "Lei Li", "Guixia Zhao", "Fenlei Niu", "Qifei Huang", "Zhenwu Tang", "Xiangke Wang" ], "corpus_id": 104298969, "doc_id": "104298969", "n_citations": 114, "n_key_citations": 0, "score": 0, "title": "A critical review on visible light response CeO2 based photocatalysts with enhanced photooxidation of organic pollutants", "venue": "Catalysis Today", "year": 2019 }, { "abstract": "Abstract Among the admired photocatalysts, metal sulphide based semiconductors are most prominent photocatalysts for the degradation or decomposition of dyes in wastewater industries with low cost, environment friendly and sustainable treatment technologies for the environmental protection. In recent years, the environmental pollution poses a serious threat to the environment and public health. To overcome the environmental pollution, doped and heterojunction based semiconductor metal sulfide nanostructures (MSNSs) are developed as photocatalysts for the purpose of photocatalytic degradation or removal of large organic dyes in an eco friendly and sustainable fashion. This comprehensive review starts with a brief overview on dyes as pollutants, dyes classification, dyes decolorization or degradation strategies and focuses on the mechanisms involved in comparatively well understood MSNSs photocatalysts such as ZnS, CdS, CuS, Ag2S, Bi2S3, CoS, FeS, and PbS etc. It particularly discusses the recent advancements to enhance photocatalytic degradation of toxic dyes by using various MSNSs to make it a flexible and cost effective commercial dye treatment technology. In addition, we have focused on the treatment of organic dyes using different types of MSNSs by photocatalysis and the effects of various parameters such as dopants, heterojunctions, band gap, size, light intensity, surface area, reaction time, and degradation efficiency, etc. are highlighted.", "author_names": [ "Dasari Ayodhya", "Guttena Veerabhadram" ], "corpus_id": 139362452, "doc_id": "139362452", "n_citations": 96, "n_key_citations": 0, "score": 0, "title": "A review on recent advances in photodegradation of dyes using doped and heterojunction based semiconductor metal sulfide nanostructures for environmental protection", "venue": "", "year": 2018 } ]

[ { "abstract": "Semiconductor wafer map data provides valuable information for semiconductor engineers. Correctly classified defect patterns in wafer maps can increase semiconductor productivity. Convolutional Neural Networks (CNN) achieved excellent performance on computer vision and were frequently used method in wafer map classification. The CNN based classifier of the wafer map defect pattern requires a sufficiently large training set to ensure high performance. However, for the real semiconductor production environment, it is challenging to collect various defect patterns enough. In this paper, we propose a method to supplement the lack of training set using Generative Adversarial Networks (GAN) to improve the performance of the classifier. We measure our performance on the 'WM 811k' dataset, which consists of 811K real world wafer maps. We compare the performance of our classifiers with commonly used augmentation techniques. As a result, we achieved remarkable performance enhancement from 97.0% to 98.3%", "author_names": [ "YongSung Ji", "Jee-Hyong Lee" ], "corpus_id": 221568319, "doc_id": "221568319", "n_citations": 2, "n_key_citations": 0, "score": 1, "title": "Using GAN to Improve CNN Performance of Wafer Map Defect Type Classification Yield Enhancement", "venue": "2020 31st Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2020 }, { "abstract": "In this paper, we study a new estimation system for the prediction of steam generator tube defects. In the previous research works, defect size estimators were independently designed for each defect types in order to estimate the defect size. As a result, the structure of estimation system is rather complex and the estimation performance gets worse if the classification performance is degraded for some reason. This paper studies a new estimation system that does not require the classification of defect types. Although the previous works are expected to achieve much better estimation performance than the proposed system since it uses the estimator specialized in each defect, the performance difference is not so large. Therefore, it is expected that the proposed estimator can be effectively used for the case where the defect type classification is imperfect.", "author_names": [ "Nam Hoon Jo" ], "corpus_id": 108040960, "doc_id": "108040960", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Performance Evaluation of SG Tube Defect Size Estimation System in the Absence of Defect Type Classification", "venue": "", "year": 2010 }, { "abstract": "In semiconductor manufacturing, a wafer bin map (WBM) represents the results of wafer testing for dies using a binary pass or fail value. For WBMs, defective dies are often clustered into groups of local systematic defects. Determining their specific patterns is important, because different patterns are related to different root causes of failure. Recently, because wafer sizes have increased and the process technology has become more complicated, the probability of observing mixed type defect patterns, i.e. two or more defect patterns in a single wafer, has increased. In this paper, we propose the use of convolutional neural networks (CNNs) to classify mixed type defect patterns in WBMs in the framework of an individual classification model for each defect pattern. Through simulated and real data examples, we show that the CNN is robust to random noise and performs effectively, even if there are many random defects in WBMs.", "author_names": [ "Kiryong Kyeong", "Heeyoung Kim" ], "corpus_id": 51878218, "doc_id": "51878218", "n_citations": 60, "n_key_citations": 12, "score": 0, "title": "Classification of Mixed Type Defect Patterns in Wafer Bin Maps Using Convolutional Neural Networks", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2018 }, { "abstract": "In this paper, we propose a solder joint defect type classification method for automatic optical inspection machines in the manufacturing system of printed circuit boards. The inspection procedure for the solder joint defect type classification consists of an offline stage, which sets the optimal feature extraction region, and an online stage which classifies a defect type. In the offline stage, we use an optimization technique, namely, the genetic algorithm, to optimize the feature extraction region. In this stage, the optimal feature extraction region for defect type classification is constructed automatically. In the online stage, feature extraction regions are used to segment the solder joint image after component image acquirement. We then extract various color features from the segmented feature extraction regions. Next, we use support vector machine, which is one of the machine learning model's method to classify the solder joint defect type. To evaluate the performance of the proposed method, ten types of solder joint defects were used in an experiment. The experimental results verified the effectiveness of the method in terms of the recognition rate, and its convenience.", "author_names": [ "Ji-Deok Song", "Young-Gyu Kim", "Tae-Hyoung Park" ], "corpus_id": 115160493, "doc_id": "115160493", "n_citations": 11, "n_key_citations": 1, "score": 0, "title": "SMT defect classification by feature extraction region optimization and machine learning", "venue": "", "year": 2019 }, { "abstract": "Defective die on a wafer map tend to cluster in distinguishable patterns, and such defect patterns can provide crucial information to identify equipment problems or process failures in the semiconductor manufacturing. Therefore, it is important to accurately and efficiently classify the defect patterns. In this paper, we propose a novel clustering based defect pattern detection and classification framework for wafer bin map (WBM) The proposed framework has many advantages. Outlier detection and defect cluster pattern extraction can be done at the same time; arbitrarily shaped cluster patterns can be detected; and there is no need to specify the number of clusters in advance. Based on WBM property, the parameters used in the clustering algorithm are fixed so that parameter sensitivity can be avoided. Since the defect patterns are classified based on extracted features, no labeled data and no supervised classification training are needed and single type patterns as well as mixed type patterns can be found. Extensive experiments conducted on a real world WM 811K dataset has shown the superiority of proposed framework. The proposed framework can also be used in a big data environment to accelerate performance.", "author_names": [ "Cheng Hao Jin", "Hyuk Jun Na", "Minghao Piao", "Gouchol Pok", "Keun Ho Ryu" ], "corpus_id": 181565565, "doc_id": "181565565", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "A Novel DBSCAN Based Defect Pattern Detection and Classification Framework for Wafer Bin Map", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2019 }, { "abstract": "INTRODUCTION Since the first description of autologous chondrocyte implantation (ACI) in 1994 different methods and improvements were established for this regenerative treatment option of large chondral defects. This study analyzes safety and short term clinical results from characterized ACI using a collagen based biphasic scaffold and evaluates prognostic factors. METHODS 433 patients with a mean age of 33.4 years and localized grade III to IV cartilage defects (ICRS classification) in the knee or ankle were included. Mean defect size was 5.9 cm(2) Prior seeding of the scaffold, expanded chondrocytes were characterized by RT PCR on 6 different marker genes (type I and II collagen, aggrecan, interleukin 1 b (IL 1b) vascular endothelial growth factor receptor 1 (FLT 1) and bone sialoprotein 2 (BSP 2) Clinical outcome was evaluated using a questionnaire for defect history, basic demographics, time elapsed from surgery, 10 point outcome assessments of pain, function and swelling. Moreover, adverse events (AEs) or subsequent treatments were recorded and analysed. RESULTS Patients improved significantly over baseline (p 0.0001) in pain, function and swelling. Subjects with later than 12 months follow up reported nominally greater mean changes. Graft failure incidence was 6% for patients with greater than one year follow up. Graft related complications were significantly higher for patellar (p 0.0001) and degenerative defects (p 0.005) Elevated expression of FLT 1 (p 0.02) or IL 1 b mRNA (p 0.03) was associated with graft related AEs. A borderline association was found for low collagen type II expression (p 0.08) CONCLUSION Early graft related AEs after ACI with a biphasic collagen scaffold are related to defect type, location and marker gene expression. The levels of significance observed for gene expression with respect to graft related AEs were subordinate to those identified in the analysis of lesion history and location.", "author_names": [ "Peter Angele", "Juergen Fritz", "Dirk Albrecht", "Jason L Koh", "Johannes Zellner" ], "corpus_id": 24797455, "doc_id": "24797455", "n_citations": 28, "n_key_citations": 1, "score": 0, "title": "Defect type, localization and marker gene expression determines early adverse events of matrix associated autologous chondrocyte implantation.", "venue": "Injury", "year": 2015 }, { "abstract": "Inspired by famous results of Drozd (1974) [13] Nazarova Roiter (1975) [42] and Bondarenko Stepochkina (2005) [8] on the importance of finite posets I with the non negative Tits quadratic form q^I:ZI Z in the representation theory, we study the finite non negative posets I of corank two, that is, such posets I that the symmetric Gram matrix GI:=12[CI+CItr]MI(Q) of I is positive semi definite of corank two, where CIMI(Z) is the incidence matrix of I. A structure of such posets is described in the paper. It is shown that every such a poset I can be obtained in a natural way from a corank zero poset J and a pair of roots of J. Following main ideas of the Coxeter spectral analysis of posets, we associate with any connected corank two poset I the incidence quadratic form qI:ZI Z, the Coxeter matrix CoxI: CICI tr, the Coxeter polynomial coxI(t)=det(tE CoxI)Z[t] its complex Coxeter spectrum speccI, the Coxeter number cIN{ the reduced Coxeter number cVIN, the incidence defect homomorphism ~I:ZI KerqIZI, and a simply laced Dynkin diagram DynI. In particular, we study the question when the Coxeter spectrum speccI of I, together with DynI, determines the incidence matrix CI of I (hence the poset I) uniquely, up to a Z congruence. By applying linear algebra techniques and a combinatorial computer aided analysis of posets, we prove that the question has an affirmative answer for connected corank two posets I, with at most 15 elements. A complete list of such posets is presented and their Coxeter type invariants are computed. It follows that |I|=6, there is only one such a poset I of cardinality 6, and 8 such posets of cardinality 7, up to the poset duality I Iop. The existence of a PhI mesh translation quiver G(RIKerqI,PhI) on the set RIKerqI is discussed, where RI={vZI;qI(v)=1} is the set of roots of qI.", "author_names": [ "Marcin Gasiorek", "Daniel Simson", "Katarzyna Zajac" ], "corpus_id": 119376812, "doc_id": "119376812", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Structure and a Coxeter Dynkin type classification of corank two non negative posets", "venue": "", "year": 2015 }, { "abstract": "Abstract A novel multiple hyper spheres support vector machine with additional information (MHSVM+ is proposed for multi class steel surface defects classification. Originated from binary twin hyper spheres support vector machine, MHSVM+ uses hyper sphere to solve classification decision problem. Differently, MHSVM+ is a multi class classifier, where it builds a corresponding hyper sphere for each type of defect dataset. Moreover, MHSVM+ introduces learning paradigm using additional information, which means it can learn additional information hidden in defect dataset. Two types of additional information are provided: local neighbor information and local density information. Local neighbor information contains local classification results for defect samples. And local density information is used to capture label noise, isolated samples and important samples in defect dataset. The above two types of additional information are introduced into MHSVM+ model. Finally, MHSVM+ classifier is used to classify six types of steel surface defects. Experimental results show that the novel multi class classifier has perfect classification accuracy for defect dataset, especially corrupted defect dataset.", "author_names": [ "Rong-fen Gong", "Chengdong Wu", "Maoxiang Chu" ], "corpus_id": 125211183, "doc_id": "125211183", "n_citations": 18, "n_key_citations": 0, "score": 0, "title": "Steel surface defect classification using multiple hyper spheres support vector machine with additional information", "venue": "", "year": 2018 }, { "abstract": "In Timor Leste, the coffee is one of the most important product for the acquisition of foreign currency. However, there are almost no rationalizations, therefore, enhancing the value of the coffee efficiently at the local of production is desired. The final objective of our study is to develop the automatic coffee beans sorting system for the producers of coffee beans in Timor Leste. As the first step, we developed an image processing system which classifies the images of green coffee beans into each type of defect. We employed deep convolutional neural networks, the state of the art machine learning technique, for the image processing. As the results, we succeeded to sort defect beans from 72.4% to 98.7% of accuracies based on the types of defects.", "author_names": [ "Carlito Pinto", "Junya Furukawa", "Hidekazu Fukai", "Satoshi Tamura" ], "corpus_id": 23830455, "doc_id": "23830455", "n_citations": 23, "n_key_citations": 3, "score": 0, "title": "Classification of Green coffee bean images basec on defect types using convolutional neural network (CNN)", "venue": "2017 International Conference on Advanced Informatics, Concepts, Theory, and Applications (ICAICTA)", "year": 2017 }, { "abstract": "ABSTRACT In semiconductor manufacturing, a wafer bin map (WBM) is a map that consists of assigned bin values for dies based on wafer test results (e.g. value 1 for good dies and value 0 for defective dies) The bin values of adjacent dies are often spatially correlated, forming some systematic defect patterns. These non random defect patterns occur due to assignable causes; therefore, it is important to identify these systematic defect patterns in order to know the root causes of failure and to take actions for quality management and yield enhancement. In particular, as wafer fabrication processes have become more complicated, mixed type defect patterns (two or more different types of defect patterns occur simultaneously in a single wafer) occur more frequently than in the past. For more effective classification of wafers based on their defect patterns, mixed type defect patterns need to be detected and separated into several clusters of different patterns; subsequently, each cluster of a single pattern can be matched to a well known defect type (e.g. scratch, ring) or it may indicate the emergence of a new defect pattern. There are several challenges to be overcome in the detection and clustering of mixed type defect patterns. These include (i) the separation of random defects from systematic defect patterns; (ii) determining the number of clusters; and (iii) the clustering of defect patterns of complex shapes. To address these challenges, in this article, we propose a new framework for detecting and clustering mixed type defect patterns. First, we propose a new filtering method, called the connected path filtering method, to denoise WBMs. Subsequently, we adopt the infinite warped mixture model for the clustering of mixed type defect patterns; this model is flexible in its ability to deal with complex shapes of defect patterns; furthermore, the number of clusters does not need to be specified in advance but is automatically determined simultaneously during the clustering procedure. We validate the proposed method using real data from a semiconductor company. The experimental results demonstrate the effectiveness of the proposed method in estimating the number of underlying clusters as well as in the clustering of mixed type defect patterns.", "author_names": [ "Jinho Kim", "Youngmin Lee", "Heeyoung Kim" ], "corpus_id": 117208054, "doc_id": "117208054", "n_citations": 31, "n_key_citations": 4, "score": 0, "title": "Detection and clustering of mixed type defect patterns in wafer bin maps", "venue": "", "year": 2016 } ]

[ { "abstract": "In this study, we will compare the study done by different researchers on the semiconductor II VI group material by using different models including DMR (Diffusivity Mobility Ratio) We will check out the DMR and other model parameters used to compare the performance of semiconductor II VI group material. The basic formulation and the study of these models will help us to understand the basic properties of the nanomaterials studied so far. Keywords: DMR, Einstein relation, models, nanomaterial, semiconductor material group II VI", "author_names": [ "Rahul Jain", "Kh Gopal Krishna Singh" ], "corpus_id": 127554516, "doc_id": "127554516", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Comparative study of models for II VI group semiconductor nanomaterials using DMR", "venue": "", "year": 2018 }, { "abstract": "On decreasing size down to nanoscale, the physical, optical and quantum mechanical properties of the materials no longer remain constant but become tuneable. In order to understand these unusual properties of nanomaterials, some theoretical models and experiments have been proposed from various perspectives. The explanation of energy band gap increment can be presented in terms of quantum confinement effect. A simple model based on cohesive and activation energy, free from adjustable parameters to calculate the size and shape dependent band gap expansion is derived for the semiconductor nanocompounds. The model predicts that the energy band gap increases on decreasing the size of the particle of nanomaterial semiconductors. Also, it is seen that the effects of shape alter the band gap energy of nanomaterials and this effect on band gap energy becomes larger with the decrease in particle size. Our predictions are very consistent with the available experimented data and the simulation results.", "author_names": [ "Madan Singh", "Abhishek Singhal" ], "corpus_id": 195697674, "doc_id": "195697674", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Modeling of Shape and Size Effects for the Band Gap of Semiconductor Nanoparticles", "venue": "2018 2nd International Conference on Micro Electronics and Telecommunication Engineering (ICMETE)", "year": 2018 }, { "abstract": "Abstract In the current paper the properties of surface plasmon polaritons as well as hybrid polarized surface electromagnetic waves at the plane interface of a porous semiconductor nanomaterial and a hypercrystal are studied theoretically and numerically. The nanomaterial, as well as the hypercrystal, is made of n type doped indium antimonide (n InSb) semiconductor layers. The losses which inherent to the semiconductor materials are taken into account. To describe the properties of the constituent semiconductor layers the approximate analytical temperature models for concentration and mobility of conduction electrons are applied. This allows to consider the effect of electron scattering on the properties of supported electromagnetic modes in the wide frequency range. The contacting materials are considered in the subwavelength approximation when it is possible to introduce the effective permittivity components. It is shown that taking into account dissipation processes in the semiconductor constituent layers result in the appearance of additional surface modes branches, changes in the surface waves penetration depth, frequency and angular existence domains.", "author_names": [ "Illia V Fedorin" ], "corpus_id": 201269355, "doc_id": "201269355", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Surface electromagnetic waves at the interface between dissipative porous nanocomposite and hypercrystal under different temperatures", "venue": "Physics Letters A", "year": 2019 }, { "abstract": "Photoelectrochemical (PEC) analysis is a new detection technique developed in recent years, which has the advantages of high sensitivity, low background signal and desirable selectivity, obtaining the great progress in sensing applications. Semiconductor nanomaterials with excellent photoelectric activity have played a vital role in the construction of PEC sensing platform. Thus, this Review introduces the recent advances of semiconductor nanomaterials based PEC analysis, and describes the typical PEC sensing strategies. Some representative nanomaterials, including metallic oxides, metallic sulfides, graphitic carbon nitride, transition metal dichalcogenides and quantum dots, are summarized for advanced PEC devices, as well as their applications in nucleic acid analysis, immunoassays, cell detection, protein and enzyme sensing, and small biomolecule monitoring. Finally, some future opportunities and challenges of PEC biosensing are also discussed.", "author_names": [ "Yang Zang", "Jing Fan", "Yun Ju", "Huaiguo Xue", "Huan Pang" ], "corpus_id": 26072256, "doc_id": "26072256", "n_citations": 49, "n_key_citations": 0, "score": 0, "title": "Current Advances in Semiconductor Nanomaterial Based Photoelectrochemical Biosensing.", "venue": "Chemistry", "year": 2018 }, { "abstract": "", "author_names": [ "Aisha Salem" ], "corpus_id": 225647873, "doc_id": "225647873", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "On New Mathematical Modeling Measuringthe Band Gap of Semiconductor in Nanomaterial", "venue": "", "year": 2020 }, { "abstract": "Nanosized semiconductive Pd containing sensor materials based on SnO2 were obtained by sol gel technique. The highly sensitive gas sensor based on 1.41 wt% Pd/SnO2 nanomaterial showed the maximum response value of 12.4 to 930 ppm CH4, and the kinetics of the sensor conductivity response and recovery were studied. The average particle size of the material with the highest response to methane was 14 15 nm. Study of the CH4 oxidation kinetics on the surface of the 1.41 wt% Pd/SnO2 sensor nanomaterial allowed the proposal of a theoretical model that can describe the kinetics of the conductivity response and recovery for such Pd doped sensors to methane. The values of the methane oxidation activation energies obtained from the experimental kinetic data for the CH4 oxidation reaction on the 1.41 wt% Pd/SnO2 gas sensitive material and the model based on the data of the sensor conductivity response and recovery were almost the same, indicating a leading role for the heterogeneous catalytic oxidation reaction occurring on the sensor surface.", "author_names": [ "Ludmila Oleksenko", "George Fedorenko", "Nelly Maksymovych" ], "corpus_id": 198196948, "doc_id": "198196948", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Effect of heterogeneous catalytic methane oxidation on kinetics of conductivity response of adsorption semiconductor sensors based on Pd/SnO2 nanomaterial", "venue": "Research on Chemical Intermediates", "year": 2019 }, { "abstract": "Abstract The modelling and simulation of low dimensional nanoelectronic devices is important, because the semiconductor industry has scaled transistors down to the sub 10 n m regime. The top of the barrier (ToB) transistor model has been developed and used to model transistors that are composed of various semiconducting materials. In this paper, a brief overview of the ToB transistor model is presented. The main objective of this paper is to provide a focused review on the device modelling milestones that have been achieved using the ToB transistor model. The accuracy of a few of these models is assessed by computing the normalised root mean square deviation. The ToB transistor model is widely used for computational studies on low dimensional field effect transistors with various channel materials, such as ultra thin bodies, two dimensional materials and one dimensional materials. The ToB transistor model is also useful for extensive research in circuit level simulations. In summary, this nanoscale model helps researchers to identify and evaluate the potential nanomaterials for future nanoelectronic applications.", "author_names": [ "Mu Wen Chuan", "Kien Liong Wong", "Afiq Hamzah", "Shahrizal Rusli", "Nurul Ezaila Alias", "Cheng Siong Lim", "Michael L P Tan" ], "corpus_id": 213705250, "doc_id": "213705250", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "A review of the top of the barrier nanotransistor models for semiconductor nanomaterials", "venue": "", "year": 2020 }, { "abstract": "We study the performance of production planning models for wafer fabs in a rolling horizon setting under stochastic demand modeled using the Martingale Model of Forecast Evolution (MMFE) The models differ in how they incorporate lead times and safety stocks. The number of frozen periods is considered as an experimental factor to study the nervousness of the resulting plans. Our simulation experiments show that chance constrained production planning models that integrate safety stock and production planning decisions outperform others. The formulations with workload dependent lead times also outperform those with fixed lead times that are an integer multiple of the period length.", "author_names": [ "Timm Ziarnetzky", "Lars Monch", "Reha Uzsoy" ], "corpus_id": 211056905, "doc_id": "211056905", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Simulation Based Performance Assessment of Production Planning Models With Safety Stock and Forecast Evolution in Semiconductor Wafer Fabrication", "venue": "IEEE Transactions on Semiconductor Manufacturing", "year": 2020 }, { "abstract": "We report the development of a highly specific semiconductor quantum dots (QDs) based whole cell imaging sensor that offer rapid, reproducible, accurate, and long term cell imaging system on silanized microscope glass slides. The QD based imaging sensor involved capture of whole cells with QD labeled highly specific antibodies against over expressed cell membrane proteins. The QDs were first modified with a polymer coating to generate carboxyl groups on the surface. Using the carboxylated QDs, antibodies were covalent conjugated using carbodiimide chemistry to form 2(0)Ab~QD that were used to capture whole cell. The SK BR3 cell line was used as a model analyte in the sandwich type assay consisting of 1(0)Ab SK BR3 Ab' 2(0)Ab~QD. The assay was immobilized on an antibody modified silanized microscope slide that was subsequently mounted on a fluorescence microscope for detection. The results indicated that the QD based imaging sensor exhibited brighter signals compared with organic dye Texas red. The QD based whole cell imaging sensor was visible under the microscope even after one week without fixation.", "author_names": [ "Hengyi Xu", "Zoraida P Aguilar", "Hua Wei", "Andrew Z Wang" ], "corpus_id": 34025365, "doc_id": "34025365", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Development of semiconductor nanomaterial whole cell imaging sensor on glass slides.", "venue": "Frontiers in bioscience", "year": 2011 }, { "abstract": "In designing and optimizing new generation nanomaterials and related quantum devices, dissipation versus decoherence phenomena are often accounted for via local scattering models, such as relaxation time and Boltzmann like schemes. Here we show that the use of such local scattering approaches within the Wigner function formalism may lead to unphysical results, namely anomalous suppression of intersubband relaxation, incorrect thermalization dynamics, and violation of probability density positivity. Furthermore, we propose a quantum mechanical generalization of relaxation time and Boltzmann like models, resulting in nonlocal scattering superoperators that enable one to overcome such limitations.", "author_names": [ "Rita Claudia Iotti", "Fabrizio Dolcini", "Fausto Rossi" ], "corpus_id": 59362146, "doc_id": "59362146", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Wigner function formalism applied to semiconductor quantum devices: Need for nonlocal scattering models", "venue": "", "year": 2017 } ]

[ { "abstract": "Abstract This work provides additional insight into the threshold voltage instability effect generally observed, to varying degrees, in SiC MOSFETs, and discusses the need for an improved test method to unambiguously separate out good devices from bad ones. Threshold voltage stability is affected primarily by active charge traps in the near interfacial region of the insulating gate oxide. Their close proximity to the semiconductor interface leads to a strong time dependence of the direct tunneling mechanism in response to changes in gate bias. Bias temperature stressing can induce additional active oxide traps that can then participate in this instability. This time dependence is not properly accounted for in the existing test methods for assessing high temperature gate bias (HTGB) effects.", "author_names": [ "Aivars J Lelis", "Ronald Green", "Daniel B Habersat" ], "corpus_id": 103060518, "doc_id": "103060518", "n_citations": 19, "n_key_citations": 0, "score": 1, "title": "SiC MOSFET threshold stability issues", "venue": "", "year": 2017 }, { "abstract": "There are a number of potential reliability issues associated with SiC power MOSFETs, including threshold voltage stability, gate oxide reliability, body diode robustness, short circuit current robustness, and radiation effects. This work is primarily focused on threshold voltage stability and the need for an improved test method to unambiguously separate out good devices from bad ones. Threshold voltage stability is affected primarily by active charge traps in the near interfacial region of the insulating gate oxide. Their close proximity to the semiconductor interface leads to a strong time dependence in the direct tunneling mechanism in response to changes in gate bias. This time dependence is not properly accounted for in the existing test methods for assessing high temperature gate bias (HTGB) effects, which allow temporary removal of bias during cool down and significant un biased delay (up to 96 hours) before the post stress measurements are performed. However, this delay, introduced to accommodate the practical constraints of industrial testing, renders this test practically meaningless due to the significant recovery that occurs in the charge states of the near interfacial oxide traps. This difficulty can be overcome by reapplying the gate bias for a brief period of time before measuring. Details of the nature of the near interfacial oxide traps will be discussed, including their activation energy. All this work will be presented within the context of standards development within JEDEC, and a new SiC power devices qualification working group.", "author_names": [ "Aivars J Lelis", "Ronald Green", "Daniel B Habersat" ], "corpus_id": 25444649, "doc_id": "25444649", "n_citations": 16, "n_key_citations": 0, "score": 0, "title": "SiC MOSFET reliability and implications for qualification testing", "venue": "2017 IEEE International Reliability Physics Symposium (IRPS)", "year": 2017 }, { "abstract": "We have investigated the effect of high temperature annealing of phosphorus doped poly on gate oxide integrity and device reliability. In NMOS capacitance analysis, unstable flat band voltage characteristics and lower oxide breakdown electric field were observed in wafers which received high temperature poly annealing at 1100 degC. Gate oxide integrity (GOI/Vramp) tests and time dependent dielectric breakdown (TDDB) tests were performed to evaluate wafer level reliability. Degraded GOI characteristics and poor gate oxide lifetime were obtained for the high temperature poly annealed condition. To evaluate package level reliability, high temperature gate bias (HTGB) stress tests were conducted. Some samples failed in positive gate bias stress and more severe negative threshold voltage shift was observed in negative gate bias stress for the high temperature poly annealed condition.", "author_names": [ "Kwang-won Lee", "Young Ho Seo", "Taeseop Lee", "Kyeong Seok Park", "Martin Domeij", "Fredrik Allerstam", "T Neyer" ], "corpus_id": 212870237, "doc_id": "212870237", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effect of Phosphorus Doped Poly Annealing on Threshold Voltage Stability and Thermal Oxide Reliability in 4H SiC MOSFET", "venue": "", "year": 2019 }, { "abstract": "Abstract Silicon carbide power MOSFETs are used in numerous studies to improve the efficiency or the performance of power electronic converters. However, the gate oxide technology weakness is a main reliability issue of silicon carbide MOSFET transistors. The threshold voltage shift is a critical phenomenon that addresses the reliability of industrial power applications. It is important to have a better understanding of the phenomena implied in the gate threshold voltage shift. In this context, a static ageing test based on JEDEC standard is proposed and the resulting gate oxide stress is studied and discussed in this paper. Complementary testing was performed with dynamic reliability and gate oxide characterizations, such as the charge pumping technique. The results obtained are used to add insight to the current discussion of SiC MOSFET robustness. Additionally test benches and measurement protocols established on 1.7 kV 45 mO are detailed, which will be useful for the next generation of SiC MOSFET.", "author_names": [ "Quentin Molin", "Mehdi Kanoun", "Christophe Raynaud", "Herve Morel" ], "corpus_id": 53526107, "doc_id": "53526107", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Measurement and analysis of SiC MOSFET threshold voltage shift", "venue": "Microelectron. Reliab.", "year": 2018 }, { "abstract": "Despite the recent progress in SiC power MOSFET technology and its commercialization, the defective MOS interface still hampers the exploitation of the full potential of these devices. We present results using our high k gate stack technology that shows significantly reduced density of interface states (Dit) along with superior threshold voltage (VTH) stability for low voltage SiC power MOSFETs. The findings indicate virtually no VTH shift during static characterization as function of the starting gate voltage and its ramp. Furthermore, dynamic switching results show virtually no threshold voltage shift for $V_{GS,start} \\gt 12$V.", "author_names": [ "Stephan Wirths", "Yulieth Arango", "Andrei Mihaila", "Marco Bellini", "Gianpaolo Romano", "Giovanni Alfieri", "Manuel Belanche", "Lars Knoll", "E Bianda", "Elena Mengotti" ], "corpus_id": 221283144, "doc_id": "221283144", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Vertical Power SiC MOSFETs with High k Gate Dielectrics and Superior Threshold Voltage Stability", "venue": "2020 32nd International Symposium on Power Semiconductor Devices and ICs (ISPSD)", "year": 2020 }, { "abstract": "The new era of power semiconductor devices is exploiting the high potential of wide bandgap device based high frequency power converters. The advanced capabilities of Silicon carbide (SiC) semiconductors allow the power converters to switch at higher switching frequencies with lower switching and conduction losses. Operation under higher switching frequencies can drastically reduce the output filter requirements in grid connected converters. At higher frequencies, an L type filter can sufficiently eliminate the switching frequency harmonics. This will reduce the size and cost of the filter, which eventually results in the optimised system cost. In this paper, the filter requirements of SiC based high frequency converters are investigated. Usage of LCL filters to remove high frequency harmonic will shift the resonance frequency to high frequency region, where these harmonics can create electromagnetic compatibility issues. In industries, passive damping is utilised for mitigating these oscillations. This will result in additional losses and compromise the advantages of SiC devices. Even though active damping can be utilised to eliminate resonance oscillations, the high bandwidth processors and measurement devices may increase the cost further. Simulation study is conducted on PSCAD/MATLAB and the experimental verification using Cree SiC devices verify the filter requirements, stability issues, and possible mitigating solutions for high frequency grid converters.", "author_names": [ "Blessy John", "Arindam Ghosh", "Firuz Zare" ], "corpus_id": 146686286, "doc_id": "146686286", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Investigation on filter requirements and stability effects of SiC MOSFET based high frequency grid connected converters", "venue": "The Journal of Engineering", "year": 2019 }, { "abstract": "1,200 V and 1,700 V SiC power MOSFETs from multiple suppliers were subject to dc and pulsed current stress of the body diode. Three of the five suppliers of 1,200 V devices evaluated showed no significant bipolar degradation, but the other two supplier's devices showed varying degrees of degradation due this bipolar phenomenon. Electrical results of newly released 1,700 V devices from two suppliers showed significant degradation in the body diode and MOSFET I V characteristics following both dc and pulsed current stress of their body diodes. The electrical results presented in this work are consistent with basal plane dislocations (BPDs) that form stacking faults during forward conduction of the body diode. Significant drift in the body diode forward voltage and MOSFET on resistance indicates that a much higher BPD density may be present in 1,700 V devices in comparison to the more mature 1,200 V device offerings. The likely presence of BPDs can lead to significant reliability issues in some modern SiC power MOSFETs, and their distribution seems to vary across suppliers and among devices with the same rating and from the same supplier. These differences are likely due to variations in wafer and device processing among suppliers and within a given product line from a single supplier.", "author_names": [ "Ronald Green", "Aivars J Lelis", "Franklin L L Nouketcha" ], "corpus_id": 210748025, "doc_id": "210748025", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Effects of Pulsed and DC Body Diode Current Stress on the Stability of 1200 V SiC MOSFET I V Characteristics", "venue": "", "year": 2019 }, { "abstract": "Due to the breakneck switching speed, SiC mosfet is extremely sensitive to parasitics in the power device, circuit layout, and also measurement probe. It is not clear how the parasitics of measurement probes affect the transient stability of SiC mosfet, and it poses an unsolved challenge for the industrial field. This paper focuses to uncover the transient instability mechanism of SiC mosfet intruded by probes. Mathematical and circuit models of voltage and current probes are created, by considering the parasitics, input impedance, and bandwidth issues. To reveal the stability principles of SiC mosfet associated with probes, impedance oriented and heterogeneity synthesized models combining device with probes are proposed. Furthermore, an assessment methodology and root locus analysis are presented to demonstrate the transient stability schemes and the stable boundaries of SiC mosfet influenced by multiple factors, including probe parasitics, device parameters, gate resistances, and snubber circuits. Comparative experiments are presented to confirm the transient behaviors of SiC mosfet intruded by probe parasitics and regulated by control circuits. It is proven that, because of low bandwidth specifications, the large input capacitance of the voltage probe and coil inductance of the current probe degrade the transient stability of SiC mosfet. Due to the deteriorated stability margin of SiC mosfet intruded by the inserted parasitics of probes, instability may also be activated by using the small gate resistance. The snubber circuit is helpful to enhance the transient stability. Advanced probes with high bandwidth and high impedance are crucially needed for stable measurement of wide bandgap power devices like SiC mosfet.", "author_names": [ "Zheng Zeng", "Xin Min Zhang", "Frede Blaabjerg", "Linjing Miao" ], "corpus_id": 197434559, "doc_id": "197434559", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Impedance Oriented Transient Instability Modeling of SiC mosfet Intruded by Measurement Probes", "venue": "IEEE Transactions on Power Electronics", "year": 2020 }, { "abstract": "Although the body diode of SiC MOSFET has excellent surge capability, the reliability issues about commercial SiC MOSFET under repetitive surge current stress of body diode haven't been studied thoroughly. In this work, repetitive surge current stress is applied to the body diode of commercial SiC trench MOSFET, and the surge tests are conducted under different gate biases and ambient temperatures. It is found that no bipolar degradation occurs in the body diode but degradation phenomena of gate oxide and package are observed in devices under tests (DUTs) At room temperature, the threshold voltage (VTH) related to gate oxide degradation degrades more seriously at a negative gate bias of 5V than at OV. At OV gate bias, gate oxide and package degenerate more severely at $125^\\circ}{C} than at $25^\\circ}{C} The evolution of on state resistance (R_{DSON} during the tests is influenced by the competitive mechanism between gate oxide degradation and package degradation. As a result, gate oxide degradation causes RDSON to reduce while package degradation makes RDSON rise. Meanwhile, the competitive mechanism is deeply influenced by the gate bias voltage and ambient temperature. The failure analysis shows that all DUTs fail with gate and source terminal shorted, which is mainly attributed to high junction temperature.", "author_names": [ "Zhenyu Wang", "Yunjia Li", "Xiaohua Sun", "Ye Liu", "Zhengyun Zhu", "Na Ren", "Qing Guo" ], "corpus_id": 232062050, "doc_id": "232062050", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Reliability Investigation on SiC Trench MOSFET under Repetitive Surge Current Stress of Body Diode", "venue": "2020 IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia)", "year": 2020 }, { "abstract": "An overview over issues and findings in SiC power MOSFET reliability is given. The focus of this article is on threshold instabilities and the differences to Si power MOSFETs. Measurement techniques for the characterization of the threshold voltage instabilities are compared and discussed. Modeling of the threshold voltage instabilities based on capture emission time (CET) maps is a central topic. This modeling approach takes the complete gate bias/temperature history into account. It includes both gate stress polarities and is able to reproduce the short term threshold variations during application relevant 50 kHz bipolar ac stress. In addition, the impact on circuit operation is discussed.", "author_names": [ "Katja Puschkarsky", "Tibor Grasser", "Thomas Aichinger", "Wolfgang Gustin", "Hans Reisinger" ], "corpus_id": 207829290, "doc_id": "207829290", "n_citations": 29, "n_key_citations": 3, "score": 0, "title": "Review on SiC MOSFETs High Voltage Device Reliability Focusing on Threshold Voltage Instability", "venue": "IEEE Transactions on Electron Devices", "year": 2019 } ]

[ { "abstract": "Optical neural networks offer radically new avenues for ultrafast, energy efficient hardware for machine learning and artificial intelligence. Reservoir Computing (RC) given its high performance and cheap training has attracted considerable attention for photonic neural network implementations, principally based on semiconductor lasers (SLs) Among SLs, Vertical Cavity Surface Emitting Lasers (VCSELs) possess unique attributes, e.g. high speed, low power, rich dynamics, reduced cost, ease to integrate in array architectures, making them valuable candidates for future photonic neural networks. This work provides a comprehensive analysis of a telecom wavelength GHz rate VCSEL RC system, revealing the impact of key system parameters on its performance across different processing tasks.", "author_names": [ "Julian Bueno", "Joshua Robertson", "Matej Hejda", "Antonio Hurtado" ], "corpus_id": 235556483, "doc_id": "235556483", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Comprehensive Performance Analysis of a VCSEL Based Photonic Reservoir Computer", "venue": "IEEE Photonics Technology Letters", "year": 2021 }, { "abstract": "A face pumped Nd:YAG slab laser with high power output and temperature fluctuation adaptability is proposed and demonstrated for the first time. A two dimensional (2D) vertical cavity surface emitting laser (VCSEL) array at 808 nm with a low wavelength shift coefficient is used as the pump source with a total pump power of 1.38 kW. The array is cooled by a double layer vascularized macro channel heat sink for effective heat management. A 1064 nm maximum power of 437 W from the slab laser is obtained by optimizing the output coupling, and the power variation is only 4.9% over the temperature range from 16 degC to 34 degC. The results show that the high power slab laser pumped by VCSEL has an excellent performance in temperature tolerance and lower requirements for coolant, which is only water cooled by the macro channel heat sink and no need for deionized water; it also provides a solution for high power lasers used in the complicated environment. Furthermore, it is possible to scale the output power to ~kW level by further increasing the VCSEL pump power.", "author_names": [ "Peng-Cheng Di", "Xue-peng Li", "Rujia Wang", "Xiao-Jun Wang", "Da-Fu Cui", "Qin-Jun Peng" ], "corpus_id": 232372886, "doc_id": "232372886", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "High Power VCSEL Pumped Slab Laser With Temperature Fluctuation Adaptability", "venue": "IEEE Photonics Technology Letters", "year": 2021 }, { "abstract": "Applying a reverse bias near the breakdown voltage results in photon emission at the pn junction in vertical cavity surface emitting lasers (VCSELs) This radiation can be collected with an emission microscope. Here, this technique is employed to investigate a high power two dimensional (2D) VCSEL array with a large number of emitters at a non degraded state and after high electrical stress. It has been found that non degraded arrays show varying photon intensities across all emitters at breakdown condition while degraded arrays exhibit more intense electroluminescence at areas with faulty emitters containing defects in the active area as confirmed by plan view scanning transmission electron microscopy analysis.", "author_names": [ "Roberto Cesco Fabbro", "Thomas Haber", "Gernot Fasching", "Raffaele Coppeta", "Michael Pusterhofer", "W Grogger" ], "corpus_id": 234852892, "doc_id": "234852892", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Defect localization in high power vertical cavity surface emitting laser arrays by means of reverse biased emission microscopy", "venue": "", "year": 2021 }, { "abstract": "In this work, we demonstrate a novel high power vertical cavity surface emitting laser (VCSEL) array with highly single mode (SM) and single polarized output performance without significantly increasing the intra cavity loss and threshold current (Ith) By combining a low loss zinc diffusion aperture with an electroplated copper substrate, we can obtain a highly SM output (side mode suppression ratio >50dB) with a very narrow divergence angle (1/e2:~10) under high output power (3.1 W; 1% duty cycle) and sustain a single polarization state, with a polarization suppression ratio of around 9 dB, under the full range of bias currents. Compared to the reference device without the copper substrate, the demonstrated array can not only switch the output optical spectra from quasi SM to highly SM but also maintain a close threshold current value (Ith: 0.8 versus 0.7 mA per unit device) and slope efficiency. The enhancement in fundamental mode selectivity of our VCSEL structure can be attributed to the single polarized lasing mode induced by tensile strain, which is caused by the electroplated copper substrate, as verified by the double crystal x ray measurement results.", "author_names": [ "Jin-Wei Shi", "Zuhaib Khan", "Ray-Hua Horng", "Hsiao-Yun Yeh", "Chun-Kai Huang", "Cheng-Yi Liu", "Jie-Chen Shih", "Yung-Hao Chang", "J L Yen", "Jinn-Kong Sheu" ], "corpus_id": 221467010, "doc_id": "221467010", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "High power and single mode VCSEL arrays with single polarized outputs by using package induced tensile strain.", "venue": "Optics letters", "year": 2020 }, { "abstract": "Novel 940 nm (quasi )coherent VCSEL array (3x3) is demonstrated. It exhibits high power (62.4 mW) single spot output with narrow divergence angle ~5deg) over the full range of bias currents, and wide 3 dB E 0 bandwidth (10 GHz)", "author_names": [ "Zuhaib Khan", "Jie-Chen Shin", "Yung-Hao Chang", "Jin-Wei Shi" ], "corpus_id": 221716083, "doc_id": "221716083", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "High Brightness and High Speed Coherent VCSEL Array", "venue": "2020 Conference on Lasers and Electro Optics (CLEO)", "year": 2020 }, { "abstract": "Abstract In this paper, we investigated high power selectively oxidation confined AlxGa1 xAs/GaAs 850 nm vertical cavity surface emitting laser (VCSEL) and fabricated two dimensional VCSEL arrays by photolithography using photo masks. Inductively coupled plasma (ICP) was employed to create the deep platform during the mesa process. The number of illuminating lasers has been designed at 60, 85, and 109 in the array. We further studied the influence of the number of illuminating lasers on the characteristics of the VCSEL devices. The threshold current was found to be increased significantly at about 93 mA, 118 mA, and 149 mA, respectively. The injection current should produce a greater than the critical current density to meet the criteria for population inversion. However, the corresponding voltage remained almost unchanged, in the range of 1.57 1.63 V. The maximum optical output power was increased even more appreciably. It was measured at 448 mW, 592 mW, and 746 mW, respectively. On the other hand, the device equivalent series resistance was decreased with more illumination lasers in the array. The averaged resistance has been estimated at 4.16 O, 3.14 O, and 2.47 O, respectively. In addition, the optical spectrum became more dispersed, showing more lasing modes for the samples with the highest number in illumination lasers in the array. The peak wavelength full width at half maximum was also slightly increased. The related electro optical characteristics have been summarized and further discussed.", "author_names": [ "G M Wu", "F C Kung", "Chiau Yeng Lee" ], "corpus_id": 214102135, "doc_id": "214102135", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Study of fabrication and characterization of high power 850 nm vertical cavity surface emitting laser arrays", "venue": "", "year": 2020 }, { "abstract": "High power vertical cavity surface emitting laser (VCSEL) arrays with multiple emitters have been receiving remarkable attention currently due to their emerging applications in consumer market such as 3D sensing illumination laser source in mobile devices as well as in automotive LIDAR applications. Failure mode analysis will help provide useful information for VCSEL array design and process improvement. However, using solely general physical failure analysis techniques is insufficient. The challenge of failure mechanism study is how to locate and capture the small physical defects in the early stage since it may randomly occur in the entire active region of the emitter This work developed 3D transmission electron microscopy (TEM) method, that is, planar view TEM together cross section TEM, to investigate failure mode phenomenon in this kind of high power VCSEL arrays. Overstressed reliability testing intentionally create failure in VCSEL arrays where dim emitters are found. Optical microscope images can't see any abnormality while infrared microscope can catch small 'mouse bite' abnormality at oxide aperture. Planar view TEM method is developed to isolate the target dim emitter and trim away most of the top and bottom DBR layers to keep the oxide layer and active region to thin enough where 200KV electron beam can penetrate planar view lamella. The whole oxide aperture is achieved and scanning TEM images clearly show the 'flower like' oxide blasters at oxide aperture periphery. It is from further oxidation of the oxide tip. Cross section TEM reveal the oxide layer morphology where the further oxidation layer from oxide tip is thinner than the original oxide layer. The oxide tip further oxidation is possibly due to non reaction steam in existence in the oxide causing the second oxidation of oxide layer during overstress test. This work demonstrate that 3D TEM method is good technique to catch small physical failure features in VCSEL arrays, which will help to analyze failure mode in high power VCSEL arrays for 3D sensing application.", "author_names": [ "Xiaoyan Wang", "Jefferson M Abrenica", "Patrick Koh" ], "corpus_id": 216227350, "doc_id": "216227350", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "3D transmission electron microscopy method development for failure analysis in VCSEL arrays", "venue": "Photonics Europe", "year": 2020 }, { "abstract": "We present the design and test results of a 4 channel 10 Gbps/ch Vertical Cavity Surface Emitting Laser array driver, the cpVLAD. With on chip charge pumps to extend the biasing headroom for the VCSELs needed for low temperature operation and mitigation of the radiation effects. The cpVLAD was fabricated in a 65 nm CMOS technology. The test results show that the cpVLAD is capable of driving VCSELs with forward bias voltages as high as 2.8 V from a 2.5 V power supply. The power consumption of the cpVLAD is 94 mW/ch.", "author_names": [ "X Huang", "Datao Gong", "Q Sun", "Chong-shun Chen", "Di Guo", "Suen Ray Hou", "G Huang", "Szymon Kulis", "C Liu", "T Liu", "Paulo Moreira", "A S'anchez Rodr'iguez", "H L Sun", "Jan Troska", "L Xiao", "Longkun Zhang", "W Zhang", "J Ye" ], "corpus_id": 219125351, "doc_id": "219125351", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A 4 Channel 10 Gbps/ch CMOS VCSEL Array Driver with on chip Charge Pumps", "venue": "", "year": 2020 }, { "abstract": "Future ultra broadband and low latency radio access networks pose stringent specifications for time synchronizations. For 5G base stations, inter site timing error should be 130ns for carrier aggregation and <10ns for high accuracy positioning [1] requiring a 10 10 level relative drift for a 1min clock holdover. Meanwhile, massive deployments of compact access nodes also make small size, power, and cost indispensable for clocks. Oven controlled crystal/MEMS oscillators (OCXO/OCMO) with moderate cost are currently used. But, their resonators exhibit long term aging and high temperature sensitivity 31ppm/K for MEMS resonators) hence requiring up to a watt level heater power for temperature stabilization. Referencing clocks to invariant physical constants well solves the drifting issue. To this end, chip scale atomic (Cs or Rb) clocks (CSACs) [2] [4] have achieved outstanding stability, low power (120mW in [3] and miniaturization. However, the highly complicated optical electrical components (e.g. VCSEL laser with high wavelength accuracy) integration, and packaging (e.g. heater with mK accuracy temperature control, magnetic shield, buffer gas) lead to very high cost 1k) [3] Recently, molecular clock referenced to sub THz rotational transitions of carbonyl sulfide (OCS) gas emerged as a fully electronic solution with high stability [5] In particular, chip scale molecular clock (CSMC) built using a CMOS chip coupled with a waveguide OCS molecular cell, appeared as highly attractive for miniaturization and significant cost reduction. In [5] the long term stability (3.8x10 10@averaging time \\tau=10^ 3}\\mathrm{S} of the CSMC was limited by the non ideal measured OCS transition curve, which is susceptible to environmental disturbance. This paper presents a 70mW CSMC chip design that enables high order dispersion curve locking and enhances the long term stability by 9x. Additional testing results also reveal its advantages in temperature stability over OCXO/OCMO and magnetic sensitivity over CSAC, respectively.", "author_names": [ "Cheng Wang", "Xiang Yi", "Mina Kim", "Ruonan Han" ], "corpus_id": 215799908, "doc_id": "215799908", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "29.5 Sub THz CMOS Molecular Clock with 43ppt Long Term Stability Using High Order Rotational Transition Probing and Slot Array Couplers", "venue": "2020 IEEE International Solid State Circuits Conference (ISSCC)", "year": 2020 }, { "abstract": "Metal grids are used to solve the current spreading problem in coherently coupled implant defined vertical cavity surface emitting laser (VCSEL) arrays. In phase mode operation with a near diffraction limited beam is achieved in hexagonal 19 element arrays. The measured beamwidth of the arrays is as low as 1.3deg, which is only about 1.08 times of the diffraction limit. The arrays can maintain a relatively high proportion of 29.2% average power in the central lobe from threshold to maximum output power. The narrow beamwidth and high power proportion benefit from the uniform near field optical intensity owing to the metal grids. This technique provides an alternative method to realize large area in phase coherently coupled VCSEL array with high beam quality.", "author_names": [ "Guanzhong Pan", "Yiyang Xie", "Chen Xu", "Qiuhua Wang", "Yibo Dong", "Jun Deng", "Hongda Chen", "Jie Sun" ], "corpus_id": 203654578, "doc_id": "203654578", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "In Phased Implant Defined Hexagonal VCSEL Array With Near Diffraction Limited Beam", "venue": "IEEE Photonics Technology Letters", "year": 2019 } ]

[ { "abstract": "Fluorescent carbon nanoparticles or carbon quantum dots (CQDs) are a new class of carbon nanomaterials that have emerged recently and have garnered much interest as potential competitors to conventional semiconductor quantum dots. In addition to their comparable optical properties, CQDs have the desired advantages of low toxicity, environmental friendliness low cost and simple synthetic routes. Moreover, surface passivation and functionalization of CQDs allow for the control of their physicochemical properties. Since their discovery, CQDs have found many applications in the fields of chemical sensing, biosensing, bioimaging, nanomedicine, photocatalysis and electrocatalysis. This article reviews the progress in the research and development of CQDs with an emphasis on their synthesis, functionalization and technical applications along with some discussion on challenges and perspectives in this exciting and promising field.", "author_names": [ "Shi Ying Lim", "Wei Shen", "Zhiqiang Gao" ], "corpus_id": 19393519, "doc_id": "19393519", "n_citations": 2473, "n_key_citations": 21, "score": 0, "title": "Carbon quantum dots and their applications.", "venue": "Chemical Society reviews", "year": 2015 }, { "abstract": "Strategies for selectively imaging and delivering drugs to tumours typically leverage differentially upregulated surface molecules on cancer cells. Here, we show that intravenously injected carbon quantum dots, functionalized with multiple paired a carboxyl and amino groups that bind to the large neutral amino acid transporter 1 (which is expressed in most tumours) selectively accumulate in human tumour xenografts in mice and in an orthotopic mouse model of human glioma. The functionalized quantum dots, which structurally mimic large amino acids and can be loaded with aromatic drugs through p p stacking interactions, enabled in the absence of detectable toxicity near infrared fluorescence and photoacoustic imaging of the tumours and a reduction in tumour burden after the targeted delivery of chemotherapeutics to the tumours. The versatility of functionalization and high tumour selectivity of the quantum dots make them broadly suitable for tumour specific imaging and drug delivery. Intravenously injected functionalized carbon quantum dots that bind to the large neutral amino acid transporter 1 and that structurally mimic large amino acids selectively accumulate in human tumours in mice, facilitating targeted theranostics.", "author_names": [ "Shuhua Li", "Wen Su", "Hao Wu", "Ting Yuan", "Chang Yuan", "Jun Liu", "Gang Deng", "Xingchun Gao", "Zeming Chen", "Youmei Bao", "Fanglong Yuan", "Shixin Zhou", "Hongwei Tan", "Yunchao Li", "Xiaohong Li", "Louzhen Fan", "Jia Zhu", "Ann Tai Chen", "Fuyao Liu", "Yu Zhou", "Miao Li", "Xingchen Zhai", "Jiangbing Zhou" ], "corpus_id": 214704171, "doc_id": "214704171", "n_citations": 45, "n_key_citations": 1, "score": 0, "title": "Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids", "venue": "Nature Biomedical Engineering", "year": 2020 }, { "abstract": "Carbon quantum dots (CQDs) as an emerging class of quantum dots (QDs) with advantages such as good photoluminescence (PL) properties, easy synthesis routes, economical synthesis, cheap starting materials, water solubility, low levels of toxicity, chemical stability, and easy functionalization have received great attention during recent years. CQDs have been used in versatile sensor applications. CQD sensors could be ultimately sensitive, and the limit of detection (LOD) for these sensors can reach the nanomolar, picomolar or even femtomolar ranges. CQD based sensors and biosensors work with different mechanisms including fluorescence quenching, static quenching, dynamic quenching, energy transfer, inner filter effect (IFE) photo induced electron transfer (PET) and fluorescence resonance energy transfer (FRET) CQD based sensors and biosensors have been applied for the detection of different species such as metal ions, acids, proteins, biothiols, polypeptides, DNA and miRNA, water pollutants, hematin, drugs, vitamins, and other chemicals. It seems that CQD based sensors and biosensors are promising candidates for high performance and yet accurate sensors in different areas. In this review, CQDs are introduced, and the synthesis methods and optical properties of CQDs are discussed. Different types of CQD based sensors and biosensors and their working mechanisms are clarified.", "author_names": [ "Mohammad Jafar Molaei" ], "corpus_id": 213782522, "doc_id": "213782522", "n_citations": 46, "n_key_citations": 0, "score": 1, "title": "Principles, mechanisms, and application of carbon quantum dots in sensors: a review", "venue": "", "year": 2020 }, { "abstract": "Efficient full color fluorescent carbon quantum dots are synthesized by acid reagent engineering for white light emitting devices. Quantum dots have innate advantages as the key component of optoelectronic devices. For white light emitting diodes (WLEDs) the modulation of the spectrum and color of the device often involves various quantum dots of different emission wavelengths. Here, we fabricate a series of carbon quantum dots (CQDs) through a scalable acid reagent engineering strategy. The growing electron withdrawing groups on the surface of CQDs that originated from acid reagents boost their photoluminescence wavelength red shift and raise their particle sizes, elucidating the quantum size effect. These CQDs emit bright and remarkably stable full color fluorescence ranging from blue to red light and even white light. Full color emissive polymer films and all types of high color rendering index WLEDs are synthesized by mixing multiple kinds of CQDs in appropriate ratios. The universal electron donating/withdrawing group engineering approach for synthesizing tunable emissive CQDs will facilitate the progress of carbon based luminescent materials for manufacturing forward looking films and devices.", "author_names": [ "Liang Wang", "Weitao Li", "Luqiao Yin", "Yijiang Liu", "Huazhang Guo", "Jiawei Lai", "Yu Han", "Gao Li", "Ming Li", "Jianhua Zhang", "Robert Vajtai", "Pulickel M Ajayan", "Minghong Wu" ], "corpus_id": 222110938, "doc_id": "222110938", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Full color fluorescent carbon quantum dots", "venue": "Science Advances", "year": 2020 }, { "abstract": "Large doses of anticancer drugs entering cancer cell nuclei are found to be effective at killing cancer cells and increasing chemotherapeutic effectiveness. Here we report red emissive carbon quantum dots, which can enter into the nuclei of not only cancer cells but also cancer stem cells. After doxorubicin was loaded at the concentration of 30 mg/mL on the surfaces of carbon quantum dots, the average cell viability of HeLa cells was decreased to only 21% while it was decreased to 50% for free doxorubicin. The doxorubicin loaded carbon quantum dots also exhibited a good therapeutic effect by eliminating cancer stem cells. This work provides a potential strategy for developing carbon quantum dot based anticancer drug carriers for effective eradication of cancers.", "author_names": [ "Wen Su", "Ruihua Guo", "Fanglong Yuan", "Yunchao Li", "Xiaohong Li", "Yang Zhang", "Shixin Zhou", "Louzhen Fan" ], "corpus_id": 211035565, "doc_id": "211035565", "n_citations": 25, "n_key_citations": 0, "score": 0, "title": "Red Emissive Carbon Quantum Dots for Nuclear Drug Delivery in Cancer Stem Cells.", "venue": "The journal of physical chemistry letters", "year": 2020 }, { "abstract": "Abstract Currently, the disposal of municipal wastes (paper, plastic, and coffee residue) is a problem due to increasing the amount of municipal wastes, global environmental problems, and high disposal cost. Here, we report the synthesis of carbon quantum dots from waste paper by different solvents by a conventional hydro /solvothermal method for solving the environmental and disposal problems. The carbon quantum dots synthesized with waste papers have several advantages such as low toxicity, low cost, and eco friendly. The prepared carbon quantum dots have main emission peak from 440 to 540 nm under 340 480 nm excitation. The prepared carbon quantum dots can be applied to easily prepare anti counterfeiting ink and fluorescent flexible film because of their unique optical property and excellent chemical and photostability.", "author_names": [ "Sung Jun Park", "Jin Young Park", "Jong Won Chung", "Hyun Kyoung Yang", "Byung Kee Moon", "Soung Soo Yi" ], "corpus_id": 208735373, "doc_id": "208735373", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Color tunable carbon quantum dots from wasted paper by different solvents for anti counterfeiting and fluorescent flexible film", "venue": "", "year": 2020 }, { "abstract": "Carbon and graphene quantum dots are prepared using top down and bottom up methods. Sustainable synthesis of quantum dots has several advantages such as the use of low cost and non toxic raw materials, simple operations, expeditious reactions, renewable resources and straightforward post processing steps. These nanomaterials are promising for clinical and biomedical sciences, especially in bioimaging, diagnosis, bioanalytical assays and biosensors. Here we review green methods for the fabrication of quantum dots, and biomedical and biotechnological applications.", "author_names": [ "Siavash Iravani", "Rajender S Varma" ], "corpus_id": 212643318, "doc_id": "212643318", "n_citations": 71, "n_key_citations": 1, "score": 0, "title": "Green synthesis, biomedical and biotechnological applications of carbon and graphene quantum dots. A review", "venue": "Environmental Chemistry Letters", "year": 2020 }, { "abstract": "Nitrogen doped carbon quantum dots (N CQDs) were successfully synthesized using rice residue and glycine as carbon and nitrogen sources by one step hydrothermal method. High quantum yield (23.48% originated from the effective combination of nitrogen with various functional groups (CO, NH, CN, COOH and COC) The N CQDs showed a fluorescence with the wavelength varied from 420 to 500 nm and the maximum emission wavelength being at 440 nm. N CQDs have been importantly applied as probe to detect Fe3+ and tetracycline (TCs) antibiotics with remarkable performance. Using the linear relationship between fluorescence intensity and Fe3+ concentration, the N CQDs could be employed as a simple, efficient sensor for ultrasensitive Fe3+ detection ranging from 3.32 to 32.26 uM, with a limit of detection (LOD) of 0.7462 uM. The N CQDs showed the applicability to detect TCs. The detection limits of tetracycline, terramycin and chlortetracycline were 0.2367, 0.3739 and 0.2791 uM, respectively. The results of TC by fluorescence method in real water samples were in good agreement with standard Ultraviolet visible (UV vis) method. The N CQDs have various potential applications including sensitive and selective detection of Fe3+ and TCs, and cellular imaging with low cytotoxicity, good biocompatibility and high permeability.", "author_names": [ "Houjuan Qi", "Min Teng", "Miao Liu", "Shouxin Liu", "Jian Li", "Haipeng Yu", "Chunbo Teng", "Zhanhua Huang", "Hu Liu", "Qian Shao", "Ahmad Umar", "Tao Ding", "Qiang Gao", "Zhanhu Guo" ], "corpus_id": 58602387, "doc_id": "58602387", "n_citations": 187, "n_key_citations": 1, "score": 0, "title": "Biomass derived nitrogen doped carbon quantum dots: highly selective fluorescent probe for detecting Fe3+ ions and tetracyclines.", "venue": "Journal of colloid and interface science", "year": 2019 }, { "abstract": "Therapeutic options for the highly pathogenic human coronavirus (HCoV) infections are urgently needed. Anticoronavirus therapy is however challenging, as coronaviruses are biologically diverse and rapidly mutating. In this work, the antiviral activity of seven different carbon quantum dots (CQDs) for the treatment of human coronavirus HCoV 229E infections was investigated. The first generation of antiviral CQDs was derived from hydrothermal carbonization of ethylenediamine/citric acid as carbon precursors and postmodified with boronic acid ligands. These nanostructures showed a concentration dependent virus inactivation with an estimated EC50 of 52 8 mg mL 1. CQDs derived from 4 aminophenylboronic acid without any further modification resulted in the second generation of anti HCoV nanomaterials with an EC50 lowered to 5.2 0.7 mg mL 1. The underlying mechanism of action of these CQDs was revealed to be inhibition of HCoV 229E entry that could be due to interaction of the functional groups of the CQDs with HCoV 229E entry receptors; surprisingly, an equally large inhibition activity was observed at the viral replication step.", "author_names": [ "Aleksandra Loczechin", "Karin Seron", "Alexandre Barras", "Emerson Giovanelli", "Sandrine Belouzard", "Yen-Ting Chen", "Nils Metzler-Nolte", "Rabah Boukherroub", "Jean Dubuisson", "Sabine Szunerits" ], "corpus_id": 204814784, "doc_id": "204814784", "n_citations": 104, "n_key_citations": 2, "score": 0, "title": "Functional Carbon Quantum Dots as Medical Countermeasures to Human Coronavirus", "venue": "ACS applied materials interfaces", "year": 2019 }, { "abstract": "Abstract Microbial contamination and antibiotic pollutions diffusely exist in wastewater system, and contaminated water poses a threat to public health. Therefore, there is a need to effectively remove biohazard and antibiotic contamination from wastewater systems. In this paper, sulfur doped carbon quantum dots (S CQDs)/hollow tubular g C3N4 photocatalyst (HTCN C) prepared via ultrasonic assisted synthesis strategy, was regarded as an efficient catalyst for the degradation of antibiotic (tetracycline) and destruction of a typical Gram negative bacterium (Escherichia coli) in imitated wastewater system. The unique structures of hollow tubular g C3N4 and loading of modified carbon quantum dots enhanced electron transfer and charge separation, leading to a significant improvement in photocatalytic efficiency. Benefiting from these merits, the optimized catalysts (HTCN C(2) exhibited superior performance with a reaction rate of 0.0293 min 1 for tetracycline (TC) degradation and 99.99% destruction of Escherichia coli under visible light irradiation. Moreover, the characterization of UV Vis diffuse reflectance spectra, photoluminescence technique, transient photocurrent responses and electrochemical impedance spectroscopy also verified the good optical and electrochemical properties of resultant samples. Our current work indicates that HTCN C has great potential in degradation of antibiotic and destruction of bacterium for practical wastewater treatment.", "author_names": [ "Wenjun Wang", "Zhuotong Zeng", "Guangming Zeng", "Chen Zhang", "Rong Xiao", "Chengyun Zhou", "Weiping Xiong", "Yongxiang Yang", "Lei Lei", "Yang Liu", "Danlian Huang", "Min Cheng", "Ya-Ya Yang", "Yukui Fu", "Hanzhuo Luo", "Yin Zhou" ], "corpus_id": 198367887, "doc_id": "198367887", "n_citations": 169, "n_key_citations": 0, "score": 0, "title": "Sulfur doped carbon quantum dots loaded hollow tubular g C3N4 as novel photocatalyst for destruction of Escherichia coli and tetracycline degradation under visible light", "venue": "", "year": 2019 } ]

[ { "abstract": "Since the early 1980s, most electronics have relied on the use of complementary metal oxide semiconductor (CMOS) transistors. However, the principles of CMOS operation, involving a switchable semiconductor conductance controlled by an insulating gate, have remained largely unchanged, even as transistors are miniaturized to sizes of 10 nanometres. We investigated what dimensionally scalable logic technology beyond CMOS could provide improvements in efficiency and performance for von Neumann architectures and enable growth in emerging computing such as artifical intelligence. Such a computing technology needs to allow progressive miniaturization, reduce switching energy, improve device interconnection and provide a complete logic and memory family. Here we propose a scalable spintronic logic device that operates via spin orbit transduction (the coupling of an electron's angular momentum with its linear momentum) combined with magnetoelectric switching. The device uses advanced quantum materials, especially correlated oxides and topological states of matter, for collective switching and detection. We describe progress in magnetoelectric switching and spin orbit detection of state, and show that in comparison with CMOS technology our device has superior switching energy (by a factor of 10 to 30) lower switching voltage (by a factor of 5) and enhanced logic density (by a factor of 5) In addition, its non volatility enables ultralow standby power, which is critical to modern computing. The properties of our device indicate that the proposed technology could enable the development of multi generational computing.A scalable spintronic device operating via spin orbit transduction and magnetoelectric switching and using advanced quantum materials shows non volatility and improved performance and energy efficiency compared with CMOS devices.", "author_names": [ "Sasikanth Manipatruni", "Dmitri E Nikonov", "Chia-Ching Lin", "Tanay A Gosavi", "Huichu Liu", "Bhagwati Prasad", "Yen-Lin Huang", "E Bonturim", "Ramamoorthy Ramesh", "Ian A Young" ], "corpus_id": 54444242, "doc_id": "54444242", "n_citations": 224, "n_key_citations": 6, "score": 1, "title": "Scalable energy efficient magnetoelectric spin orbit logic", "venue": "Nature", "year": 2018 }, { "abstract": "As nanoelectronics approaches the nanometer scale 1 4 a massive effort is underway to identify an energy efficient scalable logic technology beyond Complementary Metal Oxide Semiconductor (CMOS) transistor based computing 5 7 Such computing technology needs to improve switching energy and delay at reduced dimensions 8 allow improved interconnects 9 and provide a complete logic/memory family. However, a viable beyond CMOS logic technology has remained elusive. Here, we propose a scalable spintronic logic device which operates via spin orbit transduction 10 16 combined with magneto electric switching 17 20 The MagnetoElectric Spin Orbit (MESO) logic enables a new paradigm to continue scaling of logic 8,9,21 to switching energies of <10aJ per device at switching delay of 100 ps.", "author_names": [ "Ian A Young", "Sasikanth Manipatruni", "Dmitri E Nikonov", "C -C Lin", "Huquan Li", "Ramamoorthy Ramesh" ], "corpus_id": 211254845, "doc_id": "211254845", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Magneto Electric Spin Orbit Logic and Spin Orbit Memory Building Blocks for Beyond CMOS", "venue": "", "year": 2017 }, { "abstract": "In this technical note, we address the comments on the energy estimates for Magnetoelectric Spin orbit (MESO) Logic, a new logic device proposed by the authors. We provide an analytical derivation of the switching energy, and support it with time domain circuit simulations using a self consistent ferroelectric (FE) compact model. While the energy to charge a capacitor is dissipated in the interconnect and transistor resistance, we note that the energy to switch a capacitor and a FE is independent of the interconnect resistance value to the first order. Also device design can mitigate the parasitic energy losses. We further show the circuit simulations for a sub 10 aJ switching operation of a MESO logic device comprehending: a) Energy stored in multiferroic; b) Energy dissipation in the resistance of the interconnect, Ric c) Energy dissipation in the inverse spin orbit coupling (ISOC) spin to charge converter Risoc; d) Supply, ground resistance, and transistor losses. We also identify the requirements for the resistivity of the spin orbit coupling materials and address the effect of internal resistance of the spin to charge conversion layer. We provide the material parameter space where MESO (with a fan out of 1 and interconnect) achieves sub 10 aJ switching energy with path for scaling via ferroelectric/magnetoelectric/spin orbit materials development.", "author_names": [ "Sasikanth Manipatruni", "Dmitri E Nikonov", "Huichu Liu", "Ian A Young" ], "corpus_id": 113932671, "doc_id": "113932671", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Response to Comment on 'Spin Orbit Logic with Magnetoelectric Nodes: A Scalable Charge Mediated Nonvolatile Spintronic Logic' (arXiv:1607.06690)", "venue": "", "year": 2017 }, { "abstract": "As nanoelectronics approaches the nanometer scale, a massive effort is underway to identify the next scalable logic technology beyond Complementary Metal Oxide Semiconductor (CMOS) computing. Such computing technology needs to improve switching energy delay at reduced dimensions, allow improved interconnects and provide a complete logic/memory family. However, a viable beyond CMOS logic technology has remained elusive. Here, we propose a scalable spintronic logic device which operates via spin orbit transduction combined with magneto electric switching. The proposed Magneto Electric Spin Orbit (MESO) logic enables a new paradigm to continue scaling of logic performance to near thermodynamic limits for GHz logic (100 kT switching energy at 100 ps delay) The proposed MESO devices scale strongly and favorably with critical dimensions of the device, showing a cubic dependence of switching energy on size, (E_m proportional to W^3) and square dependence on voltage (E_m proportional to V^2) The excellent scaling is obtained thanks to the properties of the spin orbit effects (e.g. Inverse Spin Hall Effect (ISHE) and Inverse Rashba Edelstein Effect (IREE) and the dependence of capacitance on size. The operating voltages for these devices are predicted to be 100 mV allowing a significant jump ahead of historic trends of scaling voltage with size and corresponding reduction of energy. Interconnect resistance is a critical obstacle for scaling beyond 10 nm dimensions. We project a less detrimental impact of interconnect resistance and show that MESO logic is amenable for highly resistive interconnects (100 uOhm.cm 1 mOhm.cm) which opens a possibility to use nano metallic (width bulk electron mean free path) or doped semiconducting wires (width<5 nm) A scalable, CMOS compatible, non volatile logic family proposed here may enable the next multi generational scaling of computing devices.", "author_names": [ "Sasikanth Manipatruni", "Dmitri E Nikonov", "Ramamoorthy Ramesh", "Huichu Li", "Ian A Young" ], "corpus_id": 111652745, "doc_id": "111652745", "n_citations": 51, "n_key_citations": 4, "score": 0, "title": "Spin Orbit Logic with Magnetoelectric Nodes: A Scalable Charge Mediated Nonvolatile Spintronic Logic", "venue": "", "year": 2015 }, { "abstract": "Researchers from Intel Corporation recently proposed \"Magneto Electric Spin Orbit (MESO)\" logic as a new strategy for beyond CMOS electronics [1] The Intel researchers project that this concept has the potential to reduce the switching energy per bit \"to near thermodynamic limits for GHz logic (100 kT switching at 100 ps delay)\" i.e. to near 0.4 aJ. Here I point out that the switching energy stated in ref. [1] is incorrect, because the paper neglects a large energy cost associated with Ohmic dissipation that is unavoidable within the MESO scheme. Using optimistic parameters, the true minimum switching energy per bit within the MESO approach is at least 150 fJ, or more than 300,000 times greater than the value stated in ref. [1] Given this large energy cost, the MESO concept is not a viable strategy for beyond CMOS logic.", "author_names": [ "Daniel C Ralph" ], "corpus_id": 119234356, "doc_id": "119234356", "n_citations": 8, "n_key_citations": 0, "score": 0, "title": "Comment on \"Spin Orbit Logic with Magnetoelectric Nodes: A Scalable Charge Mediated Nonvolatile Spintronic Logic\" (arXiv:1512.05428)", "venue": "", "year": 2016 }, { "abstract": "The supply voltage scaling has become increasingly challenging in the advanced CMOS technology due to the threshold voltage requirement for transistor OFF leakage, limiting the system energy efficiency. Spintronic logic utilizes the physical quantity of magnetization or spin as a computation variable, offering new design paradigms in terms of ultralow voltage operation and nonvolatility, but suffering from switching inefficiency of the charge to spin conversion. The magnetoelectric spin orbit (MESO) device has been proposed as a new alternative logic device candidate to solve these issues by magnetoelectric transduction using a novel multiferroic oxide [both ferroelectric (FE) and antiferromagnetic] a ferromagnet and a spin injection layer. It enables a path toward 10 100 \\times switching energy reduction compared to CMOS inverter in 2018 node, due to the device and material innovations of a novel switching mechanism. In this paper, in order to build a MESO logic family for new circuit and architecture exploration, we propose for the first time the fundamental building blocks such as MESO sequential and combinatorial circuits for the synchronous logic operation. We employ a transistor sharing and a novel multiphase clocking scheme to address the circuit design issues such as clock control, directionality of state propagation, and power gating and enable the design exploration for MESO digital logic. Based on the proposed circuit techniques, we demonstrate these MESO logic functions operating at a supply voltage of 100 mV and a clock period of 1.2 ns with 320 ac FE polarization through the circuit simulations.", "author_names": [ "Huichu Liu", "Sasikanth Manipatruni", "Daniel H Morris", "Kaushik Vaidyanathan", "Dmitri E Nikonov", "Tanay Karnik", "Ian A Young" ], "corpus_id": 71150886, "doc_id": "71150886", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Synchronous Circuit Design With Beyond CMOS Magnetoelectric Spin Orbit Devices Toward 100 mV Logic", "venue": "IEEE Journal on Exploratory Solid State Computational Devices and Circuits", "year": 2019 }, { "abstract": "As electronic integrated circuits are scaled to ever smaller sizes, they run into the obstacle of excessive power dissipation. Spintronic devices hold the promise of alleviating this problem via improved energy efficiency. Research effort around a promising class of such devices based on antiferromagnetic materials and magnetoelectric switching is reviewed.", "author_names": [ "Peter A Dowben", "D E Nikonov", "A Marshall", "Christian Binek" ], "corpus_id": 214434693, "doc_id": "214434693", "n_citations": 10, "n_key_citations": 0, "score": 0, "title": "Magneto electric antiferromagnetic spin orbit logic devices", "venue": "", "year": 2020 }, { "abstract": "The spin degree of freedom in magnetic devices has been discussed widely for computing, since it could significantly reduce energy dissipation, might enable beyond Von Neumann computing, and could have applications in quantum computing. For spin based computing to become widespread, however, energy efficient logic gates comprising as few devices as possible are required. Considerable recent progress has been reported in this area. However, proposals for spin based logic either require ancillary charge based devices and circuits in each individual gate or adopt principals underlying charge based computing by employing ancillary spin based devices, which largely negates possible advantages. Here, we show that spin orbit materials possess an intrinsic basis for the execution of logic operations. We present a spin orbit logic gate that performs a universal logic operation utilizing the minimum possible number of devices, that is, the essential devices required for representing the logic operands. Also, whereas the previous proposals for spin based logic require extra devices in each individual gate to provide reconfigurability, the proposed gate is 'electrically' reconfigurable at run time simply by setting the amplitude of the clock pulse applied to the gate. We demonstrate, analytically and numerically with experimentally benchmarked models, that the gate performs logic operations and simultaneously stores the result, realizing the 'stateful' spin based logic scalable to ultralow energy dissipation.", "author_names": [ "Mohammad Kazemi" ], "corpus_id": 3326217, "doc_id": "3326217", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "An electrically reconfigurable logic gate intrinsically enabled by spin orbit materials", "venue": "Scientific Reports", "year": 2017 }, { "abstract": "As we approach the limits of CMOS scaling, researchers are developing \"beyond CMOS\" technologies to sustain the technological benefits associated with device scaling. Spin tronic technologies have emerged as a promising beyond CMOS technology due to their inherent benefits over CMOS such as high integration density, low leakage power, radiation hardness, and non volatility. These benefits make spintronic devices an attractive successor to CMOS especially for memory circuits. However, spintronic devices generally suffer from slower switching speeds and higher write energy, which limits their usability. In an effort to close the energy delay gap between CMOS and spintronics, device concepts such as CoMET (Composite Input Magnetoelectric base Logic Technology) have been introduced, which collectively leverage material phenomena such as the spin Hall effect and the magnetoelectric effect to enable fast, energy efficient device operation. In this work, we propose a non volatile flip flop (NVFF) based on CoMET technology that is capable of achieving up to two orders of magnitude less write energy than CMOS. This low write energy (2 aJ) makes our CoMET NVFF especially attractive to architectures that require frequent backup operations e.g. for energy harvesting non volatile processors.", "author_names": [ "Robert Perricone", "Zhaoxin Liang", "Meghna G Mankalale", "Michael Thaddeus Niemier", "Sachin S Sapatnekar", "Jianping Wang", "Xiaobo Sharon Hu" ], "corpus_id": 155106583, "doc_id": "155106583", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "An Energy Efficient Non Volatile Flip Flop based on CoMET Technology", "venue": "2019 Design, Automation Test in Europe Conference Exhibition (DATE)", "year": 2019 }, { "abstract": "Reliable and energy efficient magnetization switching by electrically induced spin orbit torques is of crucial technological relevance for spintronic devices implementing memory and logic functionality. Here we predict that the strength of spin orbit torques and the Dzyaloshinskii Moriya interaction in topologically nontrivial magnetic insulators can exceed by far that of conventional metals. In analogy to the quantum anomalous Hall effect, we explain this extraordinary response in the absence of longitudinal currents as hallmark of monopoles in the electronic structure of systems that are interpreted most naturally within the framework of mixed Weyl semimetals. We thereby launch the effect of spin orbit torque into the field of topology and reveal its crucial role in mediating the topological phase transitions arising from the complex interplay between magnetization direction and momentum space topology. The presented concepts may be exploited to understand and utilize magnetoelectric coupling phenomena in insulating ferromagnets and antiferromagnets.Electric field control of magnetization switching is highly promising for low dissipation spintronics. Here, the authors propose an electrically induced topological phase transition mediated by spin orbit torques as attractive way to control magnetization in absence of longitudinal charge currents.", "author_names": [ "Jan-Philipp Hanke", "Frank Freimuth", "Chengwang Niu", "Stefan Blugel", "Yuriy Mokrousov" ], "corpus_id": 31347205, "doc_id": "31347205", "n_citations": 27, "n_key_citations": 0, "score": 0, "title": "Mixed Weyl semimetals and low dissipation magnetization control in insulators by spin orbit torques", "venue": "Nature Communications", "year": 2017 } ]

[ { "abstract": "Abstract It is still a great challenge to effectively optimize the electronic structure of photocatalysts for the sustainable and efficient conversion of solar energy to H2 energy. To resolve this issue, we report on the optimization of the electronic structure of hollow concave carbon nitride (C3N4) by deviating the sp2 hybridized structure of its tri s triazine component from the two dimensional plane. The embedded CuInS2 into C3N4 (CuInS2@C3N4) demonstrates an increased light capturing capability and the promoted directional transfer of the charge carrier. Research results reveal that the hollow structure with an apparent potential difference between the concave and convex C3N4 drives the directional transfer of the photoinduced electrons from the Cu 2p orbital of CuInS2 to the N 1s orbital of C3N4 with the S scheme principle. The H2 evolution efficiency over CuInS2@C3N4 is up to 373 umol*h 1 g 1 under visible irradiation, which is 1.57 and 1.35 times higher than those over the bulk g C3N4 with 1 wt% Pt (238 umol*h 1 g 1) and g C3N4 with 3 wt% Pd (276 umol*h 1 g 1) respectively. This suggests that the apparent potential difference of the hollow C3N4 results in an efficient reaction between the photogenerated electrons and H2O. This work supplies a new strategy for enhancing the sustainable solar conversion performance of carbon nitride, which can also be suitable for other semiconductors.", "author_names": [ "Jinhua Luo", "Zhexing Lin", "Yan Zhao", "Shujuan Jiang", "Shaoqing Song" ], "corpus_id": 209708913, "doc_id": "209708913", "n_citations": 53, "n_key_citations": 0, "score": 1, "title": "The embedded CuInS2 into hollow concave carbon nitride for photocatalytic H2O splitting into H2 with S scheme principle", "venue": "", "year": 2020 }, { "abstract": "Abstract A signal on photoelectrochemical (PEC) biosensor was successfully established for the sensitive monitoring of carcinoembryonic antigen (CEA) by using copper indium disulfide sensitized graphitic like carbon nitride (g C3N4/CuInS2) as the photosensitive material and cobalt oxyhydroxide (CoOOH) as the light blocking material, coupling target triggered hybridization chain reaction (HCR) with hydrolysate induced dissolution/etching of CoOOH nanosheets. Initially, a sandwiched reaction occurred between capture aptamer conjugated magnetic bead and trigger aptamer in the presence of CEA. Then, the carried trigger aptamer initiated HCR between two hairpin sequences to produce long double helix strand for capturing alkaline phosphatase. The generated ascorbic acid reduced/etched CoOOH nanosheets into divalent cobalt ions, which decreased the amount and thickness of CoOOH and exposed the underlying g C3N4/CuInS2, thus leading to a distinct increase in the photocurrent. Under optimum conditions, PEC sensor showed high sensitivity toward CEA with a dynamic range of 0.02 40 ng mL 1 and a detection limit of 5.2 pg mL 1. Also, it possessed favorable selectivity, high stability as well as good precision. The accuracy of PEC approach was well consistent with commercial CEA ELISA kit. These exceptional analytical performances of PEC biosensor indicated that it might have a broad application prospect in the diagnosis of CEA.", "author_names": [ "Kangyao Zhang", "Shuzhen Lv", "Qian Zhou", "Dianping Tang" ], "corpus_id": 214090281, "doc_id": "214090281", "n_citations": 50, "n_key_citations": 0, "score": 1, "title": "CoOOH nanosheets coated g C3N4/CuInS2 nanohybrids for photoelectrochemical biosensor of carcinoembryonic antigen coupling hybridization chain reaction with etching reaction", "venue": "", "year": 2020 }, { "abstract": "Abstract Photocatalysis is one of the most promising technologies owing to its great potential to relieve energy and environmental issues. Constructing Z scheme heterojunction photocatalyst with strong redox ability to make for enhanced light absorption and efficient charge separation is extremely attractive but still underdeveloped. Herein, Z scheme heterojunction of CuInS2/g C3N4 with a \"sheet on sheet\" hierarchical structure showing enhanced photocatalytic performance for the tetracycline (TC) degradation under visible light irradiation has been developed. This 2D/2D hierarchical structure of CuInS2/g C3N4 composite not only enlarges the contact region in the heterojunction interface but also provides more active reaction sites, as demonstrated by the TEM and BET analyses. Particularly, 50 wt% CuInS2/g C3N4 heterojunction shows the highest photocatalytic activity (20 mg/L; 83.7% degradation within 60 min) which the apparent rate constant is 15 and 11 times higher than that of pure g C3N4 and CuInS2 nanosheets, respectively. The remarkably enhanced photocatalytic activity mainly derives from the synergistic effect between CuInS2 and g C3N4, thereby promoting the charge separation during the photocatalytic reaction. This work is expected to provide a design idea to construct multifunctional 2D/2D nanocomposites for photocatalytic applications.", "author_names": [ "Feng Guo", "Weilong Shi", "Mingyang Li", "Yuxing Shi", "Huabing Wen" ], "corpus_id": 105578120, "doc_id": "105578120", "n_citations": 118, "n_key_citations": 0, "score": 1, "title": "2D/2D Z scheme heterojunction of CuInS2/g C3N4 for enhanced visible light driven photocatalytic activity towards the degradation of tetracycline", "venue": "Separation and Purification Technology", "year": 2019 }, { "abstract": "Abstract A series of visible light driven direct Z scheme CdS/CuInS2 nanoplates were fabricated by a facile one step hydrothermal method, and the molar ratio of CdS to CuInS2 was optimized. The highest visible light photocatalytic degradation activity of Z scheme (1:0.03) CdS/CuInS2 heterojunction is about 4 times than that of pure CuInS2, which is due to the narrowest band gap, the largest BET surface area, the most efficient charge separation and transfer, and the synergistic effect between CdS and CuInS2. Meanwhile, Z scheme (1:0.03) CdS/CuInS2 heterojunction also exhibits excellent photocatalytic reduction activity with almost 100% of aqueous Cr(VI) reduction efficiency in absence of hole scavengers after 60 min. The special significance is that Z scheme (1:0.03)CdS/CuInS2 heterojunction shows excellent stability in five degradation cycles, and can effectively treat real pharmaceutical wastewater with 76.5% COD removal efficiency with aid of H2O2 in 13 h, indicating that Z scheme CdS/CuInS2 has a promising prospect in real pharmaceutical wastewater treatment.", "author_names": [ "Fang Deng", "Xiaoying Lu", "Yingbo Luo", "Jie Wang", "Wenjie Che", "Ruijie Yang", "Xubiao Luo", "Shenglian Luo", "Dionysios D Dionysiou" ], "corpus_id": 105755778, "doc_id": "105755778", "n_citations": 89, "n_key_citations": 0, "score": 0, "title": "Novel visible light driven direct Z scheme CdS/CuInS2 nanoplates for excellent photocatalytic degradation performance and highly efficient Cr(VI) reduction", "venue": "Chemical Engineering Journal", "year": 2019 }, { "abstract": "Abstract The pollution of pharmaceutical wastewater has attracted global attention. Photocatalysis is an attractive yet challenging method for the degradation of pharmaceutical residues. Fabricating efficient Z scheme heterojunctions with intimate interface contact for enhancing the performance of photocatalysts is a challenge. Herein, novel visible light driven direct Z scheme CuInS2/Bi2WO6 heterojunctions with intimate interface contact were successfully synthesized by in situ hydrothermal growth of Bi2WO6 directly on the surface of CuInS2 network like microspheres, and the content of CuInS2 was optimized. The photocatalytic activity of optimal Z scheme 15% CuInS2/Bi2WO6 for the degradation of tetracycline hydrochloride (TC*HCl) is more than three times that of bare CuInS2 and 17% higher than that of Bi2WO6, which is attributed that the intimate interface contact can assure excellent interfacial charge transfer abilities. Moreover, Z scheme CuInS2/Bi2WO6 heterojunctions are highly stable with no inactivation in photocatalytic cycles. More importantly, real pharmaceutical industry wastewater can be efficiently disposed by Fenton aided photocatalysis of Z scheme CuInS2/Bi2WO6 heterojunctions with COD removal efficiency being 90.5% which is much higher than the reported results, and thus sets a new performance benchmark for practical application in real pharmaceutical wastewater treatment.", "author_names": [ "Xiaoying Lu", "Wenjie Che", "Xiufen Hu", "Yi Wang", "Aiting Zhang", "Fang Deng", "Shenglian Luo", "Dionysios D Dionysiou" ], "corpus_id": 106025407, "doc_id": "106025407", "n_citations": 91, "n_key_citations": 1, "score": 0, "title": "The facile fabrication of novel visible light driven Z scheme CuInS2/Bi2WO6 heterojunction with intimate interface contact by in situ hydrothermal growth strategy for extraordinary photocatalytic performance", "venue": "", "year": 2019 }, { "abstract": "Abstract In order to improve the water splitting efficiency of CuInS2 in a photoelectrochemical (PEC) cell, the novel CuInS2/Sb2S3 heterostructure photocathodes modified with Pt noble metal co catalyst were prepared on the ITO substrate by the hydrothermal and electrochemical deposition method for the first time. The mechanism of the synthesis reaction for the CuInS2/Sb2S3 and CuInS2/Sb2S3/Pt were investigated. With the photoelectrochemical measurements, the photocurrent density of CuInS2/Sb2S3/Pt photoelectrode 2.48 mA/cm2 at 0.6 V vs. RHE) is about 3.13 times relatively higher than that of the corresponding the pure CuInS2 photoelectrode 0.79 mA/cm2 at 0.6 V vs. RHE) The excellent PEC behaviors profit from the modification by Sb2S3 that forms the heterostructure which broadens the response of visible light and increases the separation and transfer of photo generated carriers. Moreover, after introducing Pt co catalyst onto the surface of CuInS2/Sb2S3 photoelectrode, photo generated electrons can be captured quickly which further effectively promotes the separation of photo generated carriers and greatly improve the PEC performance. This work manifests that the structure of CuInS2/Sb2S3/Pt photocathodes has a guiding suggestion to provide a promising approach to designing a highly stabilized efficient device for photoelectrochemical water splitting.", "author_names": [ "Qijun Cai", "Zhifeng Liu", "Zhengfu Tong", "Chonghao Ma" ], "corpus_id": 164240995, "doc_id": "164240995", "n_citations": 43, "n_key_citations": 0, "score": 0, "title": "CuInS2/Sb2S3 heterostructure modified with noble metal co catalyst for efficient photoelectrochemical water splitting", "venue": "Journal of Alloys and Compounds", "year": 2019 }, { "abstract": "Developing photocatalysts with a high efficiency charge separation remains a challenge in the solar hydrogen production. Herein, we devised and prepared a unique 2D/2D heterojunction of CuInS2/ZnIn2S4 nanosheets for solar hydrogen evolution. Structural characterizations reveal that the CuInS2/ZnIn2S4 2D/2D heterojunction with lattice match consists of the thin thickness of nanosheets and has a large interface contact area, boosting charges transfer and separation. Benefiting from the favorable 2D/2D heterojunction structure, the CuInS2/ZnIn2S4 2D/2D heterojunction photocatalyst with 5 wt CuInS2 yields the highest H2 evolution rate of 3430.2 mmol*g 1*h 1. In addition, the apparent quantum efficiency of 5%CuInS2/ZnIn2S4 2D/2D heterojunction reaches 12.4% at 420 nm, which is high among the ZnIn2S4 based 2D/2D heterojunctions. The enhanced photocatalytic H2 evolution comes from the boosting charge separation. This work demonstrates that a 2D/2D heterojunction provides a potential way for significantly impro.", "author_names": [ "Zhongjie Guan", "Jingwen Pan", "Qiuye Li", "Guoqiang Li", "Jianjun Yang" ], "corpus_id": 107478125, "doc_id": "107478125", "n_citations": 58, "n_key_citations": 0, "score": 0, "title": "Boosting Visible Light Photocatalytic Hydrogen Evolution with an Efficient CuInS2/ZnIn2S4 2D/2D Heterojunction", "venue": "ACS Sustainable Chemistry Engineering", "year": 2019 }, { "abstract": "Abstract Photocatalytic CO2 reduction into solar fuels over photocatalysts has theoretically and practically become a hot research topic. Herein, we fabricated a novel hybrid TiO2 nanofiber coated by CuInS2 nanoplates through a hydrothermal method. The materials were characterized by X ray diffraction, electron microscopes, UV vis absorption spectra, nitrogen sorption, X ray photoelectron spectroscopy and electrochemical impudence spectroscopy. The resulting TiO2/CuInS2 hybrid nanofibers exhibit superior photocatalytic activity for CO2 reduction under irradiation, due to the generation of direct Z scheme heterojunction between TiO2 and CuInS2. This work may provide an alternate methodology to design and fabricate multicomponent TiO2 based photocatalyst for high efficiency CO2 photoreduction.", "author_names": [ "Feiyan Xu", "Jianjun Zhang", "Bicheng Zhu", "Jiaguo Yu", "Jingsan Xu" ], "corpus_id": 103437404, "doc_id": "103437404", "n_citations": 224, "n_key_citations": 0, "score": 0, "title": "CuInS2 sensitized TiO2 hybrid nanofibers for improved photocatalytic CO2 reduction", "venue": "", "year": 2018 }, { "abstract": "Rational architectural design and catalyst components are beneficial to improve the photoelectrochemical (PEC) performance. Herein, hierarchical SnS2/CuInS2 nanosheet heterostructure porous films were fabricated and decorated with C60 to form photocathodes for PEC water reduction. Large size CuInS2 nanosheet films were first grown on transparent conducting glass to form substrate films. Then, small size SnS2 nanosheets were epitaxially grown on both sides of the CuInS2 nanosheets to form uniform hierarchical porous laminar films. The addition of C60 on the surface of the SnS2/CuInS2 porous nanosheets effectively increased visible light absorption of the composite photocathode. Photoluminescence spectroscopy and impedance spectroscopy analyses indicated that the formation of a SnS2/CuInS2 heterojunction and decoration of C60 significantly increased the photocurrent density by promoting the electron hole separation and decreasing the resistance to the transport of charge carriers. The hierarchical SnS2/CuInS2 nanosheet heterostructure porous films containing multiscale nanosheets and pore configurations can enlarge the surface area and enhance visible light utilization. These beneficial factors make the optimized C60 decorated SnS2/CuInS2 photocathode exhibit much higher photocathodic current (4.51 mA cm 2 at applied potential 0.45 V vs reversible hydrogen electrode and stability than the individual CuInS2 (2.58 mA cm 2) and SnS2 (1.92 mA cm 2) nanosheet film photocathodes. This study not only reveals the promise of C60 decorated hierarchical SnS2/CuInS2 nanosheet heterostructure porous film photocathodes for efficient solar energy harvesting and conversion but also provides rational guidelines in designing high efficiency photoelectrodes from earth abundant and low cost materials allowing widely practical applications.", "author_names": [ "Fangfang Zhang", "Yajie Chen", "Wei Zhou", "Can Ren", "Haijing Gao", "Guohui Tian" ], "corpus_id": 73438285, "doc_id": "73438285", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "Hierarchical SnS2/CuInS2 Nanosheet Heterostructure Films Decorated with C60 for Remarkable Photoelectrochemical Water Splitting.", "venue": "ACS applied materials interfaces", "year": 2019 }, { "abstract": "Abstract Inspired by the unique structure and wide applications of zeolitic imidazolate frameworks 8 (ZIF 8) and CuInS2 (CIS) considerable attention has focused on the combination of both materials. We herein report a facial method for the homogeneous decoration of ZIF 8 onto the surfaces of CuInS2 (CIS) nanoparticles coordinated by polyvinyl pyrrolidone (PVP) in methanol. It has been shown that the coordination of PVP plays a key role in inducing the nucleation of ZIF 8 on the surface of CIS nanoparticles because of the pyrrolidone rings (C O) in PVP offering an improved affinity between CIS and Zn ions. Performing as a catalyst, the CIS@ZIF 8 nanocomposites not only exhibit high photocatalytic activity for the degradation of organic dye under UV light irradiation, but also largely maintain their catalytic efficiency after being recycled for five times compared with that of pure CIS nanoparticles.", "author_names": [ "Aiping Liu", "Chao Yu", "Jing Lin", "Guanghui Sun", "Guohai Xu", "Yang Huang", "Zhenya Liu", "Chengchun Tang" ], "corpus_id": 104302122, "doc_id": "104302122", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Construction of CuInS2@ZIF 8 nanocomposites with enhanced photocatalytic activity and durability", "venue": "Materials Research Bulletin", "year": 2019 } ]

[ { "abstract": "Semiconductor photocatalysis has received much attention as a potential solution to the worldwide energy shortage and for counteracting environmental degradation. This article reviews state of the art research activities in the field, focusing on the scientific and technological possibilities offered by photocatalytic materials. We begin with a survey of efforts to explore suitable materials and to optimize their energy band configurations for specific applications. We then examine the design and fabrication of advanced photocatalytic materials in the framework of nanotechnology. Many of the most recent advances in photocatalysis have been realized by selective control of the morphology of nanomaterials or by utilizing the collective properties of nano assembly systems. Finally, we discuss the current theoretical understanding of key aspects of photocatalytic materials. This review also highlights crucial issues that should be addressed in future research activities.", "author_names": [ "Hua Tong", "Shuxin Ouyang", "Yingpu Bi", "Naoto Umezawa", "Mitsutake Oshikiri", "Jinhua Ye" ], "corpus_id": 205242063, "doc_id": "205242063", "n_citations": 2502, "n_key_citations": 1, "score": 1, "title": "Nano photocatalytic materials: possibilities and challenges.", "venue": "Advanced materials", "year": 2012 }, { "abstract": "", "author_names": [ "Hua Tong", "Shuxin Ouyang", "Yingpu Bi", "Naoto Umezawa", "Mitsutake Oshikiri", "Jinhua Ye" ], "corpus_id": 197047875, "doc_id": "197047875", "n_citations": 337, "n_key_citations": 13, "score": 0, "title": "Nano photocatalytic Materials: Possibilities and Challenges", "venue": "", "year": 2012 }, { "abstract": "Photocatalysis is one of the most promising processes within catalysis, due to its increasing potential and the possibility of its being combined with renewable solar energy", "author_names": [ "Jose M Dona-Rodriguez", "Elisenda Pulido Melian" ], "corpus_id": 232382893, "doc_id": "232382893", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Nano Photocatalytic Materials: Possibilities and Challenges", "venue": "Nanomaterials", "year": 2021 }, { "abstract": "Graphene based metal/metal oxide composites are attracted much interest and attention as promising entrant to available biomedical devices owing to their good stability and unique properties. The fame of Graphene oxide (GO) has been on the increase due to their several applications in the fields of super capacitor and storage devices, ionic conductors and Nano sized membranes. GO is used as light emitting material, which makes it particularly suitable for various medical applications like protein bio sensing and disease discovery, targeted drug delivery and antimicrobial materials are just some of the possibilities GO holds for the biomedical field. GO can easily be mixed with different polymers and other materials, and enhance properties of composite materials like tensile strength, elasticity, conductivity and more. In this present review, discussed thoroughly with graphene based metal/metal oxide composites are used for different applications like antibacterial, antimicrobial, and biomedical etc. In future we expect fine control of the quantity of RGOhybrids is an important challenge to control toxicity.", "author_names": [ "and Gurumallesh" ], "corpus_id": 235192441, "doc_id": "235192441", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Review on Graphene Based Metal/Metal Oxide Composites and Enhanced Properties along with Biomedical Applications", "venue": "", "year": 2021 }, { "abstract": "Additive manufacturing (AM) includes a series of techniques used to create products, in several different materials, such as metal, polymer or ceramics, with digital models. The main advantage of AM is that it allows the creation of complex structures, but AM promises several additional advantages including the possibility to manufacture on demand or replacing smaller worn parts by directly building on an existing piece. Therefore, the interest for and establishment of AM is rapidly expanding, which is positive, however it is important to be aware that new techniques may also result in new challenges regarding health and safety issues. Metals in blood and possible clinical effects due to metal exposure were investigated in AM operators at one of the first serial producing AM facilities in the world during two consecutive years with implementation of preventive measures in between. As comparison, welders and office workers as control group were investigated. Health investigations comprised of surveys, lung function tests, antioxidant activity and vascular inflammation as well as renal and hepatic function analysis. AM operators had significantly reduced nickel levels in blood (10.8 vs 6.2 nmol/L) as well as improved lung function (80 vs 92% of predicted) from year 1 to year 2. This is in line with previously published results displaying reduced exposure. Blood cobalt and nickel levels correlated with previously reported urinary levels, while blood chromium did not. Multivariate modelling showed that blood cobalt, antioxidant/inflammatory marker serum amyloid A1/serum paraoxonase/arylesterase 1 activity and the hepatic markers aspartate transaminase, alanine transaminase, and alkaline phosphatase were higher in AM operators compared to controls. The study show that the selected clinical analyses could function as a complement to metal analyses in biological fluids when investigating exposure related health effects in AM operators. However, validation in larger cohorts is necessary before more definite conclusions could be drawn.", "author_names": [ "Stefan A Ljunggren", "Liam J Ward", "Pal Graff", "Anders Persson", "Malin Leijon Lind", "Helen Karlsson" ], "corpus_id": 232302966, "doc_id": "232302966", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Metal additive manufacturing and possible clinical markers for the monitoring of exposure related health effects", "venue": "PloS one", "year": 2021 }, { "abstract": "Emerging online arenas offer new possibilities for the study of online communication aided by computer assisted methods of data collection. However, these possibilities also entail certain challenges. As online data collection such as \"scraping\" of web content becomes part of the methodological repertoire of non technically inclined researchers, and as the data available for researchers to place under scrutiny grows ever more plentiful, we point to two challenges that need to be tackled if we are to grasp current developments. How can we make sense of the massive amounts of novel forms of mediated communication, and how can we approach them in an ethically sound manner? While all branches of media and communication research face these challenges, we are specifically interested in discussing them in relation to the broad field of political communication. Political communication research tries to understand and explain all forms of \"purposeful communication about politics\" (McNair 2003: 23) To do so, researchers have sampled newspaper articles, studied a selection of television broadcasts, analysed documentaries, or listened in on specific radio programmes. In the age of the mass media, these were perfectly legitimate approaches and they still are. Yet political communication research has had to expand its arsenal of approaches. During the roughly 15 years that have passed since the Web emerged as a mainstream platform for mediated communication, researchers have tried to grasp its effect on political communication. The majority of such work, however, notably relies on traditional methodological approaches. If we wish to properly understand online political communication, we need to explore novel possibilities. To assess the importance of blog posts, twitter messages and other so called social media outlets as platforms for political expression, to take one pertinent example, we first need to get an overview of the different types of these mediated forms of expression in our polity. This does not only entail intricate definitional delimitations, but also a some what daunting methodological task. Those trying to get an overview of the online communication during the latest Swedish election, for instance, would find a lot of material too much even to get a perspective on, perhaps. The number of messages or utterances users of one not very widespread service (Twitter) themselves labelled #val2010\" \"election2010\" amounted to over 100,000 during a one month period leading up to the election. Still, empirical endeavours based on such data constitute necessary steps on the way forward for political communication research. And they clearly entail some challenges.", "author_names": [ "Hallvard Moe", "Anders Olof Larsson" ], "corpus_id": 55452781, "doc_id": "55452781", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Methodological and Ethical Challenges Associated with Large scale Analyses of Online Political Communication", "venue": "", "year": 2013 }, { "abstract": "Excited state dynamics simulations are a powerful tool to investigate photo induced reactions of molecules and materials and provide complementary information to experiments. Since the applicability of these simulation techniques is limited by the costs of the underlying electronic structure calculations, we develop and assess different machine learning models for this task. The machine learning models are trained on \\emph ab initio} calculations for excited electronic states, using the methylenimmonium cation (CH$_2$NH$_2^ as a model system. For the prediction of excited state properties, multiple outputs are desirable, which is straightforward with neural networks but less explored with kernel ridge regression. We overcome this challenge for kernel ridge regression in the case of energy predictions by encoding the electronic states explicitly in the inputs, in addition to the molecular representation. We adopt this strategy also for our neural networks for comparison. Such a state encoding enables not only kernel ridge regression with multiple outputs but leads also to more accurate machine learning models for state specific properties. An important goal for excited state machine learning models is their use in dynamics simulations, which needs not only state specific information but also couplings, i.e. properties involving pairs of states. Accordingly, we investigate the performance of different models for such coupling elements. Furthermore, we explore how combining all properties in a single neural network affects the accuracy. As an ultimate test for our machine learning models, we carry out excited state dynamics simulations based on the predicted energies, forces and couplings and, thus, show the scopes and possibilities of machine learning for the treatment of electronically excited states.", "author_names": [ "Julia Westermayr", "Felix A Faber", "Anders S Christensen", "O Anatole von Lilienfeld", "Philipp Marquetand" ], "corpus_id": 209405437, "doc_id": "209405437", "n_citations": 21, "n_key_citations": 0, "score": 0, "title": "Neural networks and kernel ridge regression for excited states dynamics of CH2NH$_2^ From single state to multi state representations and multi property machine learning models", "venue": "Mach. Learn. Sci. Technol.", "year": 2020 }, { "abstract": "Along with the possibilities of lighter and stronger materials, clean water and sustainable energy, the development of nanomedicine is one of the primary reasons why huge amounts of public funding are currently going into the development of nanotechnology worldwide. The environmental risks of conventional medical products did not receive much attention until the 1990s; however, the potential environmental side effects have come under increased scientific and regulatory scrutiny in the last decade. In this Editorial, we will take a closer look at scientific and regulatory issues related to the environmental risks of nanomedical products and we will discuss some of the challenges that need to be addressed to ensure that nanomedicines are not only safe for humans but also for the environment. Although the field of nanotechnology is very broad in scope, most attention with regard to human health and environmental risks has evolved around engineered nanoparticles (ENPs) such as C60, carbon nanotubes, metals, metaloxides and quantum dots [1] At the same time, potential risks related to dendrimers and liposomes have only been raised to a lesser extent. The application of ENPs for medical use offers immense benefits within areas, such as diagnosis, targeted drug delivery and drug development [101] However, the use of ENPs in nanomedicine has not been subject to much regulatory scrutiny because existing laws and regulatory instruments are believed to also cover medical products based on nanotechnology. The extensive testing requirements prior to marketing of medicine may also contribute to the notion that the potentially negative effects will be discovered prior to marketing, that patients are adequately informed about negative side effects and that the benefits outweigh the risks or the adverse effects, should such be found to occur.", "author_names": [ "Anders Baun", "Steffen Foss Hansen" ], "corpus_id": 34744444, "doc_id": "34744444", "n_citations": 26, "n_key_citations": 1, "score": 0, "title": "Environmental challenges for nanomedicine.", "venue": "Nanomedicine", "year": 2008 }, { "abstract": "Von Neumann, the inventor of the modern computer, realized that if life is a physical process, it should be possible to implement life in other media than biochemistry. In the 1950s, he was one of the first to propose the possibility of implementing genuine living processes in computers and robots. This perspective, while still controversial, is rapidly gaining momentum in many science and engineering communities. Below, we summarize our recent activities to create artificial life from scratch in physicochemical systems. We also outline the nature of the grand science and engineering challenges faced as we seek to realize Von Neumann's vision: Integration of information processing and material production from the nano to the macroscale in technical systems.", "author_names": [ "Steen Rasmussen", "Anders Albertsen", "Harold Fellermann", "Pernille Lykke Pedersen", "Carsten Svaneborg", "Hans-Joachim Ziock" ], "corpus_id": 11332098, "doc_id": "11332098", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Assembling living materials and engineering life like technologies", "venue": "GECCO '11", "year": 2011 }, { "abstract": "Ecotoxicity data is a requirement for pre and post market registration of chemicals by European and international regulations (e.g. REACH) The algal toxicity test is frequently used in regulatory risk assessment of chemicals. In order to achieve high reliability and reproducibility the development of standardized guidelines is vital. For algal toxicity testing, the guidelines require stable and uniform conditions of parameters such as pH, temperature, carbon dioxide levels and light intensity. Nanomaterials and other so called difficult substances can interfere with light causing a large variation in results obtained hampering their regulatory acceptance. To address these challenges, we have developed LEVITATT (LED Vertical Illumination Table for Algal Toxicity Tests) The setup utilizes LED illumination from below allowing for a homogenous light distribution and temperature control while also minimizing intra sample shading. The setup optimizes the sample volume for biomass quantification and does at the same time ensure a sufficient influx of CO2 to support exponential growth of the algae. Additionally, the material of the test containers can be tailored to minimize adsorption and volatilization. When testing colored substances or particle suspensions, the use of LED lights also allows for increasing the light intensity without additional heat generation. The compact design and minimal equipment requirements increase the possibilities for implementation of the LEVITATT in a wide range of laboratories. While compliant with standardized ISO and OECD guidelines for algal toxicity testing, LEVITATT also showed a lower inter sample variability for two reference substances (3,5 Dicholorophenol and K2Cr2O7) and three nanomaterials (ZnO, CeO2, and BaSO4) compared to Erlenmeyer flasks and microtiter plates.", "author_names": [ "Lars M Skjolding", "Susanne Kruse", "Sara Norgaard Sorensen", "Rune Hjorth", "Anders Baun" ], "corpus_id": 225069590, "doc_id": "225069590", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Small Scale Setup for Algal Toxicity Testing of Nanomaterials and Other Difficult Substances.", "venue": "Journal of visualized experiments JoVE", "year": 2020 } ]

[ { "abstract": "A novel Ag3PO4/reduced graphene oxide/Bi2MoO6 (Ag3PO4/RGO/Bi2MoO6) Z scheme photocatalyst has been successfully prepared by a precipitation solvothermal method. The composition, morphology, structure and optical properties of the ternary composite were thoroughly investigated. The obtained Ag3PO4/RGO/Bi2MoO6 composite displayed significantly enhanced photocatalytic activity for the degradation of methylene blue (MB) under visible light irradiation, and its degradation rate (0.14575 min 1) was approximately 2.34, 2.63 and 4.97 times faster than that of the Ag3PO4/Bi2MoO6 composite, pure Ag3PO4 and Bi2MoO6, respectively. Meanwhile, the Ag3PO4/RGO/Bi2MoO6 composite exhibited better stability compared with pure Ag3PO4 after four consecutive reuses. In addition, it shows good photodegradation efficiency for five other dyes under visible light irradiation. The improved photocatalytic performance and stability could be ascribed to the larger surface area, extended visible light absorption capability and high efficiency separation of electron hole pairs of the Ag3PO4/RGO/Bi2MoO6 composite. Furthermore, RGO could act as a charge transmission bridge to accelerate the electron transfer from Ag3PO4 to Bi2MoO6 (Ag3PO4 RGO Bi2MoO6) in this Z scheme system; thus the photocorrosion of Ag3PO4 and the recombination of charge carriers were effectively suppressed. The energy band structure and free radical capturing experiments proved that the electrons in the conduction band (CB) of Bi2MoO6 had stronger reducibility and the holes in the valence band (VB) of Ag3PO4 had higher oxidizability. Simultaneously, combined with the results of PL spectroscopy and photoelectrochemical measurements, the mechanism of Z scheme charge transfer in the Ag3PO4/RGO/Bi2MoO6 composite was further confirmed. This study provides an idea for improving the anti photocorrosion and photocatalytic performance of photosensitive semiconductors.", "author_names": [ "Pengfei Zhu", "Yanjun Chen", "Ming Duan", "Zhihao Ren", "Min Hu" ], "corpus_id": 103681478, "doc_id": "103681478", "n_citations": 54, "n_key_citations": 1, "score": 1, "title": "Construction and mechanism of a highly efficient and stable Z scheme Ag3PO4/reduced graphene oxide/Bi2MoO6 visible light photocatalyst", "venue": "", "year": 2018 }, { "abstract": "Abstract Efficient visible light active ZnO/Bi2MoO6/AgBr nanocomposites were fabricated using ultrasonic assisted method. Crystallinity, structural, morphological, optical, and textural features of the photocatalysts were investigated by XRD, SEM, TEM, EDX, FT IR, UV Vis DRS, PL, and BET techniques. Photocatalytic performance of the ZnO sample was remarkably increased by combining with Bi2MoO6 and AgBr, due to formation of tandem n n heterojunctions. The as prepared ZnO/Bi2MoO6/AgBr nanocomposites exhibited excellent photocatalytic activity and stability under visible light in comparison with the ZnO, ZnO/Bi2MoO6, and ZnO/AgBr samples. About ~97% of RhB was removed in 70 min by the optimized ZnO/Bi2MoO6/AgBr (20% nanocomposite, which is 76.4, 4.75, and 17.3 times as fast as the ZnO, ZnO/Bi2MoO6 (20% and ZnO/AgBr (20% photocatalysts, respectively. It was confirmed that due to improved utilization of visible light, considerable separation of the charge carriers, and enlarged surface area, the ZnO/Bi2MoO6/AgBr (20% nanocomposite exhibited greatly improved photocatalytic activity in degradations of various dye contaminants under visible light illumination. In addition, plausible photocatalytic degradation mechanism for the highly enhanced performances were also proposed.", "author_names": [ "Mahsa Pirhashemi", "Aziz Habibi-Yangjeh" ], "corpus_id": 103819863, "doc_id": "103819863", "n_citations": 31, "n_key_citations": 0, "score": 1, "title": "Visible light photosensitization of ZnO by Bi2MoO6 and AgBr: Role of tandem n n heterojunctions in efficient charge transfer and photocatalytic performances", "venue": "", "year": 2018 }, { "abstract": "An in depth exploration associated with the localized surface plasmon resonance (LSPR) effect for plasmonic photoelectrochemistry (PEC) is beneficial for the development of high efficiency biosensors. A novel phenomenon on the LSPR between g C3N4/Bi2MoO6 and gold nanoparticles is investigated in a PEC aptasensing system under ultraviolet and visible light irradiation.", "author_names": [ "Zhenli Qiu", "Jian Shu", "Dianping Tang" ], "corpus_id": 48357485, "doc_id": "48357485", "n_citations": 34, "n_key_citations": 0, "score": 0, "title": "Plasmonic resonance enhanced photoelectrochemical aptasensors based on g C3N4/Bi2MoO6.", "venue": "Chemical communications", "year": 2018 }, { "abstract": "Abstract Exploring visible light active semiconductor photocatalysts is one of greatly significant issues. We show herewith the Bi2MoO6/SnO2 hybrid photocatalysts meet the requirement for degradation of organic contaminant. The Bi2MoO6/SnO2 displays better visible light catalytic activity than that of Bi2MoO6. SnO2 as co catalyst can provide more active sites as well as transfer and restrain the charge recombination, leading to the enhancement of catalytic activity. 30 wt. SnO2 emersions can degrade 90% for nitrobenzene and 97% for Rhodamine under visible light irradiation.", "author_names": [ "Baibai Liu", "Xinjuan Liu", "Mengying Ni", "Cheng Feng", "Xuedi Lei", "Can Li", "Yinyan Gong", "Leng-yuan Niu", "Jinliang Li", "Likun Pan" ], "corpus_id": 103601178, "doc_id": "103601178", "n_citations": 31, "n_key_citations": 0, "score": 0, "title": "SnO2 as co catalyst for enhanced visible light photocatalytic activity of Bi2MoO6", "venue": "", "year": 2018 }, { "abstract": "Abstract In this paper, Bi2MoO6/ZnFe2O4 heterojunctions were successfully obtained by combining electrospinning and a solvothermal technique. The morphology and loading of Bi2MoO6 nanosheets of Bi2MoO6/ZnFe2O4 heterojunctions could be controlled by adjusting the concentration of molybdenum precursor during the solvothermal process. Comparative experiments revealed that the resulting Bi2MoO6/ZnFe2O4 heterojunctions exhibit a higher visible light photocatalytic activity for the degradation of Rhodamine B (RB) than pure Bi2MoO6 or ZnFe2O4. The photocurrent and PL measurements of the Bi2MoO6/ZnFe2O4 heterojunctions also indicated an enhanced separation of photo induced electron hole pairs. Moreover, the heterojunctions could be easily recycled without a decrease in their photocatalytic activity due to their good magnetic separation performance and excellent chemical stability. Based on these findings, Bi2MoO6/ZnFe2O4 heterojunctions are a promising visible light driven photocatalyst for converting solar energy to chemical energy for environmental remediation.", "author_names": [ "Chengcheng Zhao", "Changlu Shao", "Xinghua Li", "Xiaowei Li", "Ran Tao", "Xuejiao Zhou", "Yichun Liu" ], "corpus_id": 103862693, "doc_id": "103862693", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Magnetically separable Bi2MoO6/ZnFe2O4 heterostructure nanofibers: Controllable synthesis and enhanced visible light photocatalytic activity", "venue": "", "year": 2018 }, { "abstract": "In this study, a novel few layer WS2/Bi2MoO6 heterojunction with greatly enhanced visible light photocatalytic performance was synthesized via a facile hydrothermal method. The results indicated that Bi2MoO6 nanosheets were directly grown on the surface of few layer WS2 and form plate on plate heterojunctions. The synthesized nanocomposites exhibited excellent photocatalytic activity under visible light irradiation. The optimal composite with 5 wt% WS2 showed the highest photocatalytic activity, whose degradation efficiencies and TOC removal were 99.5% and 91.7% for rhodamine B (RhB) 98.9% and 89.8% for ciprofloxacin (CIP) 76.0% and 67.8% for methylene blue (MB) and 69.3% and 58.6% for methimazole (MMI) respectively. Their excellent photocatalytic performance was predominantly ascribed to the construction of a plate on plate heterojunction structure between WS2 and Bi2MoO6, which could promote charge separation efficiency and enhance light harvesting efficiency. The present work provides a new understanding for extending the application of transition metal dichalcogenides in the field of photocatalysis.", "author_names": [ "Xiang Li", "Mengyuan Su", "Guifen Zhu", "Kaige Zhang", "Xia Zhang", "Jing Fan" ], "corpus_id": 49707038, "doc_id": "49707038", "n_citations": 26, "n_key_citations": 0, "score": 0, "title": "Fabrication of a novel few layer WS2/Bi2MoO6 plate on plate heterojunction structure with enhanced visible light photocatalytic activity.", "venue": "Dalton transactions", "year": 2018 }, { "abstract": "A class of direct plate on plate Z scheme heterojunction SnS2/Bi2MoO6 photocatalysts was synthesized via a two step hydrothermal method. The materials were characterized by X ray diffraction, scanning electron microscopy, transmission electron microscopy, X ray photoelectron spectra, Fourier transform infrared photoluminescence emission spectra, and UV vis diffuse reflectance spectroscopy. The photocatalytic activity was estimated via the degradation of crystal violet (CV) and ciprofloxacin (CIP) The experimental results indicated that the 5 wt% SnS2/Bi2MoO6 composites exhibited significantly enhanced performance in contrast to pure Bi2MoO6 or SnS2 nanoflakes, and were also superior to the popular TiO2 (P25) The degradation reaction accorded well with the first order reaction kinetics equation; the rate constant of CV using a SnS2 content of 5 wt% photocatalyst was 3.6 times that of the Bi2MoO6 and 2.4 times that of SnS2. Furthermore, a SnS2 content of 5 wt% exhibited a 1.7 times higher photocatalytic activity of CIP than that of pure Bi2MoO6, and 1.3 times that of pure SnS2. Radical trapping experiments and an electron spin resonance technique indicated that h+ and *OH were the dominant active species involved in the degradation process. A plasmonic Z scheme photocatalytic mechanism was proposed to explain the superior photocatalytic activities and efficient separation of photogenerated electrons and holes.", "author_names": [ "Haijin Liu", "Cuiwei Du", "Haokun Bai", "Yuzhao Su", "Dandan Wei", "Yuqian Wang", "Guoguang Liu", "Lin Yang" ], "corpus_id": 139503009, "doc_id": "139503009", "n_citations": 29, "n_key_citations": 0, "score": 0, "title": "Fabrication of plate on plate Z scheme SnS2/Bi2MoO6 heterojunction photocatalysts with enhanced photocatalytic activity", "venue": "Journal of Materials Science", "year": 2018 }, { "abstract": "It has been reported that photogenerated electrons and holes can be directed toward specific crystal facets of a semiconductor particle, which is believed to arise from the differences in their surface electronic structures, suggesting that different facets can act as either photoreduction or photo oxidation sites. This study examines the propensity for this effect to occur in faceted, plate like bismuth molybdate (Bi2MoO6) which is a useful photocatalyst for water oxidation. Photoexcited electrons and holes are shown to be spatially separated toward the {100} and {001}{010} facets of Bi2MoO6, respectively, by facet dependent photodeposition of noble metals (Pt, Au, and Ag) and metal oxides (PbO2, MnO x, and CoO x) Theoretical calculations revealed that differences in energy levels between the conduction bands and valence bands of the {100} and {001}{010} facets can contribute to electrons and holes being drawn to different surfaces of the plate like Bi2MoO6. Utilizing this knowledge, the photo oxidative capability of Bi2MoO6 was improved by adding an efficient water oxidation co catalyst, CoO x, to the system, whereby the extent of enhancement was shown to be governed by the co catalyst location. A greater oxygen evolution occurred when CoO x was selectively deposited on the hole rich {001}{010} facets of Bi2MoO6 compared to when CoO x was randomly located across all of the facets. The elevated performance exhibited for the selectively loaded CoO x/Bi2MoO6 was ascribed to the greater opportunity for hole trapping by the co catalyst being accentuated over other potentially detrimental effects, such as the co catalyst acting as a recombination medium and/or covering reactive sites. The results indicate that harnessing the synergy between the spatial charge separation and the co catalyst location on the appropriate facets of plate like Bi2MoO6 can promote its photocatalytic activity.", "author_names": [ "Xuelian Wu", "Judy N Hart", "Xiaoming Wen", "Liang Wang", "Yi Du", "Shi Xue Dou", "Yun Hau Ng", "Rose Amal", "Jason Scott" ], "corpus_id": 3974777, "doc_id": "3974777", "n_citations": 30, "n_key_citations": 0, "score": 0, "title": "Improving the Photo Oxidative Performance of Bi2MoO6 by Harnessing the Synergy between Spatial Charge Separation and Rational Co Catalyst Deposition.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "Abstract Bi2MoO6/reduced graphene oxide aerogel (BMO/GA) composite with enhanced adsorptivity and photocatalysis has been successfully synthesized through a simple one step solvothermal method. During solvothermal synthesis, Bi2MoO6 (BMO) as an efficient photocatalyst, which size was controllable, was uniformly distributed and well embedded into the pores of the 3D porous structure reduced graphene oxide aerogel (GA) and formed the 3D porous structure BMO/GA composite. The methylene blue (MB) was selected as a simulated pollutant, and the removal rate of BMO/GA composite toward MB was about 2.1 times as high as the pure BMO, which reached up 98.3% in 100 min. The BMO/GA composite with greatly improved adsorptivity and photocatalytic activity has some advantages of low cost, ease of preparation and facile of recovery from target contaminant solution. The excellent adsorption and photocatalytic degradation performance of BMO/GA composite is mainly owing to the BMO can be exactly embedded into the pores of GA and the RGO provided conductive electron channels for dispersing electrons. The synergistic effect of BMO and GA on enhancing the adsorption and photocatalytic degradation toward MB was also discussed by a proposed photocatalytic mechanism.", "author_names": [ "Xiang Liu", "Jue Wang", "Yuming Dong", "Hexing Li", "Yongmei Xia", "Haijun Wang" ], "corpus_id": 105379287, "doc_id": "105379287", "n_citations": 23, "n_key_citations": 1, "score": 0, "title": "One step synthesis of Bi2MoO6/reduced graphene oxide aerogel composite with enhanced adsorption and photocatalytic degradation performance for methylene blue", "venue": "", "year": 2018 }, { "abstract": "Controlled introduction of oxygen vacancies in metal oxide based photocatalysts could improve their charge carrier separation efficiencies to enhance their photocatalytic performances. In this work, oxygen vacancies were introduced in Bi2MoO6 nanosheets through a postsynthesis etching treatment by NaOH aqueous solution at room temperature for the first time, which removed the requirement of high temperature treatment, chemicals of high cost and environmental hazardness, or specific apparatus for the introduction of oxygen vacancies in previous studies. Furthermore, the crystal structure, morphology, optical properties, and energy band structures of these Bi2MoO6 nanosheets were not changed by this approach, which allowed the separation and illustration of the charge carrier separation role of oxygen vacancies for the photocatalytic performance enhancement. With the increase of oxygen vacancies, Bi2MoO6 nanosheets demonstrated improved electron hole separation efficiency and largely enhanced photocatalytic.", "author_names": [ "Chen Yan", "Weiyi Yang", "Shuang Gao", "Caixia Sun", "Qi Li" ], "corpus_id": 103326827, "doc_id": "103326827", "n_citations": 22, "n_key_citations": 0, "score": 0, "title": "Synthesis of Bi2MoO6 Nanosheets with Rich Oxygen Vacancies by Postsynthesis Etching Treatment for Enhanced Photocatalytic Performance", "venue": "", "year": 2018 } ]

[ { "abstract": "The photovoltaics of organic inorganic lead halide perovskite materials have shown rapid improvements in solar cell performance, surpassing the top efficiency of semiconductor compounds such as CdTe and CIGS (copper indium gallium selenide) used in solar cells in just about a decade. Perovskite preparation via simple and inexpensive solution processes demonstrates the immense potential of this thin film solar cell technology to become a low cost alternative to the presently commercially available photovoltaic technologies. Significant developments in almost all aspects of perovskite solar cells and discoveries of some fascinating properties of such hybrid perovskites have been made recently. This Review describes the fundamentals, recent research progress, present status, and our views on future prospects of perovskite based photovoltaics, with discussions focused on strategies to improve both intrinsic and extrinsic (environmental) stabilities of high efficiency devices. Strategies and challenges regarding compositional engineering of the hybrid perovskite structure are discussed, including potentials for developing all inorganic and lead free perovskite materials. Looking at the latest cutting edge research, the prospects for perovskite based photovoltaic and optoelectronic devices, including non photovoltaic applications such as X ray detectors and image sensing devices in industrialization, are described. In addition to the aforementioned major topics, we also review, as a background, our encounter with perovskite materials for the first solar cell application, which should inspire young researchers in chemistry and physics to identify and work on challenging interdisciplinary research problems through exchanges between academia and industry.", "author_names": [ "Ajay Kumar Jena", "Ashish Kulkarni", "Tsutomu Miyasaka" ], "corpus_id": 73480878, "doc_id": "73480878", "n_citations": 727, "n_key_citations": 0, "score": 1, "title": "Halide Perovskite Photovoltaics: Background, Status, and Future Prospects.", "venue": "Chemical reviews", "year": 2019 }, { "abstract": "Abstract In a physical vapor deposition process for fabrication of perovskite absorber layers it is an important prerequisite for large scale application to understand the reaction steps and the impact of the deposition parameters on the structural and compositional characteristics of vacuum deposited lead halide perovskite layers. In the sequential deposition method, we found a narrow and low lying temperature window for the transformation of a vapor deposited PbCl2 base layer to CH3NH3PbI3 perovskite by reaction with evaporated CH3NH3I. To modify the deposition parameter window, we systematically varied background pressure and substrate temperature and analyzed the resulting composition using X ray diffraction, energy dispersive X ray spectroscopy, and scanning electron microscopy. The resulting reaction products and byproducts CH3NH3PbI3, CH3NH3PbCl3, PbICl, PbCl2, and PbI2 were identified and the variation of their concentration in dependence of background pressure and substrate temperature is explained by discussion of a set of reaction equations and reaction mechanisms on a thermodynamic basis.", "author_names": [ "Carolin Wittich", "Eric Mankel", "Oliver Clemens", "K Lakus-Wollny", "Thomas Mayer", "Wolfram Jaegermann", "Hans Joachim Kleebe" ], "corpus_id": 103469211, "doc_id": "103469211", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Structural and compositional characteristics of vacuum deposited methylammonium lead halide perovskite layers in dependence on background pressure and substrate temperature", "venue": "", "year": 2018 }, { "abstract": "In Sn based halide perovskite solar cells (PSCs) the oxidation of Sn2+ to Sn4+ under ambient air leads to unwanted p type doping in the perovskite film, which is a main reason for increased background carrier density and low efficiency. Here, we find that the introduction of bromide into formamidinium tin iodide (CH(NH2)2SnI3, FASnI3) lattice significantly lowers the carrier density of perovskite absorber, which is thought to be a result of reduction of Sn vacancies. It reduces the leakage current of devices, increases recombination lifetime, and finally improves open circuit voltage and fill factor of the resulting devices employing mesoporous TiO2 as an electron transport layer. Consequently, a high power conversion efficiency (PCE) of 5.5% is achieved with an average PCE of 5% and after encapsulation the devices are highly stable over 1000 h under continuous one sun illumination including the ultraviolet region. This study suggests a simple approach for improving stability and efficiency in FASnI3 ba.", "author_names": [ "Seon Joo Lee", "Seong Sik Shin", "Jino Im", "Tae Kyu Ahn", "Jun Hong Noh", "Nam Joong Jeon", "Sang Il Seok", "Jangwon Seo" ], "corpus_id": 103315601, "doc_id": "103315601", "n_citations": 79, "n_key_citations": 0, "score": 0, "title": "Reducing Carrier Density in Formamidinium Tin Perovskites and Its Beneficial Effects on Stability and Efficiency of Perovskite Solar Cells", "venue": "", "year": 2018 }, { "abstract": "Abstract Perovskites are a kind of important materials used in the electronic system, information storage and energy utilization, etc. This chapter provides a brief background on perovskite materials. The typical synthesis strategies, driven by the demanding of the compositional engineering, are introduced. Due to the broad tolerance factors, compositional engineering is useful to tailor the origin structure and elemental compositions in perovskites by various synthesis methods, such as the solid state reaction, wet chemical methods, and the hydrothermal synthesis method. The sol gel method, as an important wet chemical synthesis technology, plays a key role in the doping of abundant ions and realizing of various phase/grain interfaces. BiFeO3 based and bismuth layered perovskites are thoroughly expounded in terms of compositional engineering.", "author_names": [ "Hua Ke" ], "corpus_id": 226318559, "doc_id": "226318559", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Compositional engineering of perovskite materials", "venue": "", "year": 2021 }, { "abstract": "Over the past decade, intensive research efforts have been directed toward the field of organic inorganic hybrid perovskites, with dramatic progress made in both the photovoltaic performance and device stability. Therefore, it has become the fastest growing photovoltaic research area. Perovskite materials use low cost earth abundant elements and can be solution processed; furthermore, the technology is compatible with large scale roll to roll manufacturing. Recently, the successful demonstration of the photovoltaic performance of perovskites reaching that of the commercialized monosilicon photovoltaic technology combined with the significantly improved stability has made scaling up the perovskite PV technology to become a new research area, which is the topic of this review. First, the fundamental background knowledge of classical nucleation and crystal growth from a solution is summarized along with its application in perovskite film evolution. We then discuss the common perovskite PV device architectures and perovskite layer deposition methods, followed by summarizing scalable solution approaches with recent progress and related challenges for the scaling up process. Upon the introduction of the current in depth understanding of perovskite nucleation and crystal growth, external strategies (including both physical and chemical approaches) controlling the perovskite film formation are reviewed in diverse scalable manufacturing methods. Overall, aiming at overcoming the challenges of transferring from laboratory research, we provide an overview of achieving high performance perovskite solar cells by using scalable fabrication methods via precise nucleation and crystal growth control during the perovskite film formation process.", "author_names": [ "Hanlin Hu", "Mriganka Singh", "Xuejuan Wan", "Jiao-ning Tang", "Chih-Wei Chu", "Gang Li" ], "corpus_id": 213286094, "doc_id": "213286094", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Nucleation and crystal growth control for scalable solution processed organic inorganic hybrid perovskite solar cells", "venue": "", "year": 2020 }, { "abstract": "Lead free tin halide perovskite solar cells (PSCs) have attracted great attention because of their low toxicity, ideal band gap, and high carrier mobilities. However, the efficiency and reproducibility of tin halide PSCs has been limited because of the facile oxidation of Sn2+ to Sn4+ Herein, liquid formic acid (LFA) was introduced as a reducing solvent in the FASnI3 (FA: formamidinium) perovskite precursor solution. Unlike solid reducing additives, the LFA solvent is volatile, so no residual LFA remained in the FASnI3 perovskite film. Use of the LFA solvent resulted in production of the FASnI3 perovskite film with high crystallinity, low Sn4+ content, reduced background doping, and low electronic trap density. As a result, an efficiency of over 10% was obtained for lead free tin halide PSCs with improved reproducibility.", "author_names": [ "Xiangyue Meng", "Tianhao Wu", "Xiao Liu", "Xin He", "Takeshi Noda", "Yanbo Wang", "Hiroshi Segawa", "Liyuan Han" ], "corpus_id": 214680503, "doc_id": "214680503", "n_citations": 28, "n_key_citations": 0, "score": 0, "title": "Highly Reproducible and Efficient FASnI3 Perovskite Solar Cells Fabricated with Volatilizable Reducing Solvent.", "venue": "The journal of physical chemistry letters", "year": 2020 }, { "abstract": "Over the last several years, inorganic organic hybrid perovskites have shown dramatic achievements in photovoltaic performance and device stability. Despite the significant progress in photovoltaic application, an in depth understanding of the fundamentals of precursor solution chemistry is still lacking. In this review, the fundamental background knowledge of nucleation and crystal growth processes in solution including the LaMer model and Ostwald ripening process is described. This review article also highlights the recent progress in precursor coordinating molecule interaction in solution along with the role of anti solvent in the solvent engineering process to control nucleation and crystal growth. Moreover, chemical pathways from precursor solution to perovskite film formation are given. This represents identification of the intermediate phase induced by precursor coordinating molecule interaction and responsible intermediate species for uniform and dense perovskite film formation. Further to the description of chemical phenomena in solution, the contemporary progress in chemical precursor composition is also provided to comprehend the current research approaches to further enhance photovoltaic performance and device stability. On the basis of the critical and comprehensive review, we provide some perspectives to further achieve high performance perovskite solar cells with long term device stability through precisely controlled nucleation and crystal growth in precursor solution.", "author_names": [ "Minsu Jung", "Sang-Geun Ji", "Gwisu Kim", "Sang Il Seok" ], "corpus_id": 58558340, "doc_id": "58558340", "n_citations": 177, "n_key_citations": 0, "score": 0, "title": "Perovskite precursor solution chemistry: from fundamentals to photovoltaic applications.", "venue": "Chemical Society reviews", "year": 2019 }, { "abstract": "The road ahead for perovskites The high power conversion efficiencies of small area perovskite solar cells (PSCs) have driven interest in the development of commercial devices. Rong et al. review recent progress in addressing stability, how to allow mass production, and how to maintain uniformity of large area films. They note that lifetimes exceeding 10,000 hours under 1 sun (1 kW/m2) illumination have been reported for printable triple mesoscopic PSCs. Science, this issue p. eaat8235 BACKGROUND Perovskite solar cells (PSCs) have attracted intensive attention because of their ever increasing power conversion efficiency (PCE) low cost materials constituents, and simple solution fabrication process. Initiated in 2009 with an efficiency of 3.8% PSCs have now achieved a lab scale power conversion efficiency of 23.3% rivaling the performance of commercial multicrystalline silicon solar cells, as well as copper indium gallium selenide (CIGS) and cadmium telluride (CdTe) thin film solar cells. Thousands of articles related to PSCs have been published each year since 2015, highlighting PSCs as a topic of intense interest in photovoltaics (PV) research. With high efficiencies achieved in lab devices, stability and remaining challenges in upscaling the manufacture of PSCs are two critical concerns that must be addressed on the path to PSC commercialization. ADVANCES We review recent progress in PSCs and discuss the remaining challenges along the pathway to their commercialization. Device configurations of PSCs (see the figure) include mesoscopic formal (n i p) and inverted (p i n) structures, planar formal and inverted structures, and the printable triple mesoscopic structures. PCEs of devices that use these structures have advanced rapidly in the case of small area devices ~0.1 cm2) PSCs are also attracting attention as top cells for the construction of tandem solar cells with existing mature PV technologies to increase efficiency beyond the Shockley Queisser limit of single junction devices. The stability of PSCs has attracted much well deserved attention of late, and notable progress has been made in the past few years. PSCs have recently achieved exhibited lifetimes of 10,000 hours under 1 sun (1 kW/m2) illumination with an ultraviolet filter at a stabilized temperature of 55degC and at short circuit conditions for a printable triple mesoscopic PSCs. This irradiation is equivalent to the total irradiation of 10 years of outdoor use in most of Europe. However, within the PSC community, standard testing protocols require further development. In addition, transparency in reporting standards on stability tests needs to be improved; this can be achieved by providing both initial photovoltaic performance and normalization parameters. The upscaling of PSCs has also progressed steadily, leading to PSC mini modules, standard sized modules, and power systems. PV companies have set out to manufacture large area PSC modules (see the figure) and a 110 m2 perovskite PV system with screen printed triple mesoscopic PSC modules was recently debuted. Studies of these increased area modules and systems will promote the development of PSCs toward commercialization. PSC research is expanding to cover fundamental topics on materials and lab sized cells, as well as to address issues of industrial scale manufacturing and deployment. OUTLOOK The PV market has been continuously expanding in recent years, bringing opportunities for new PV technologies of which PSCs are promising candidates. It is imperative to achieve a low cost per watt, which means that both efficiency and lifetime need improvement relative to current parameters. The efficiency gap between lab cells and industrial modules has seen impressive reductions in crystalline silicon; PSCs must similarly enlarge module areas to the panel level and need to achieve lifetimes comparable to those of legacy PV technologies. Other improvements will need to include industry scale electronic grade films, recycling methods to address concerns regarding lead toxicity, and the adoption of standardized testing protocols to predict the operation lifetime of PSCs. Modules will need to endure light induced degradation, potential induced degradation, partial shade stress, and mechanical shock. The field can benefit from lessons learned during the development of mature PV technologies as it strives to define, and overcome, the hurdles to PSC commercial impact. Configurations and application demonstration of PSCs. PSCs have been developed in various device configurations, including mesoscopic, planar, triple mesoscopic, and tandem structures. Recently, a 110 m2 perovskite PV system with printable triple mesoscopic PSC modules (3600 cm2 for each) was launched by WonderSolar in China. PHOTO: WONDERSOLAR Perovskite solar cells (PSCs) have witnessed rapidly rising power conversion efficiencies, together with advances in stability and upscaling. Despite these advances, their limited stability and need to prove upscaling remain crucial hurdles on the path to commercialization. We summarize recent advances toward commercially viable PSCs and discuss challenges that remain. We expound the development of standardized protocols to distinguish intrinsic and extrinsic degradation factors in perovskites. We review accelerated aging tests in both cells and modules and discuss the prediction of lifetimes on the basis of degradation kinetics. Mature photovoltaic solutions, which have demonstrated excellent long term stability in field applications, offer the perovskite community valuable insights into clearing the hurdles to commercialization.", "author_names": [ "Yaoguang Rong", "Yue Hu", "Anyi Mei", "Hairen Tan", "Makhsud I Saidaminov", "Sang Il Seok", "Michael D McGehee", "Edward H Sargent", "Hongwei Han" ], "corpus_id": 52306016, "doc_id": "52306016", "n_citations": 596, "n_key_citations": 1, "score": 0, "title": "Challenges for commercializing perovskite solar cells", "venue": "Science", "year": 2018 }, { "abstract": "The low power conversion efficiency (PCE) of tin based hybrid perovskite solar cells (HPSCs) is mainly attributed to the high background carrier density due to a high density of intrinsic defects such as Sn vacancies and oxidized species (Sn4+ that characterize Sn based HPSCs. Herein, this study reports on the successful reduction of the background carrier density by more than one order of magnitude by depositing near single crystalline formamidinium tin iodide (FASnI3) films with the orthorhombic a axis in the out of plane direction. Using these highly crystalline films, obtained by mixing a very small amount (0.08 m) of layered (2D) Sn perovskite with 0.92 m (3D) FASnI3, for the first time a PCE as high as 9.0% in a planar p i n device structure is achieved. These devices display negligible hysteresis and light soaking, as they benefit from very low trap assisted recombination, low shunt losses, and more efficient charge collection. This represents a 50% improvement in PCE compared to the best reference cell based on a pure FASnI3 film using SnF2 as a reducing agent. Moreover, the 2D/3D based HPSCs show considerable improved stability due to the enhanced robustness of the perovskite film compared to the reference cell.", "author_names": [ "Shuyan Shao", "Jian Liu", "Giuseppe Portale", "Hong-Hua Fang", "Graeme R Blake", "Gert H ten Brink", "L Jan Anton Koster", "Maria Antonietta Loi" ], "corpus_id": 104246786, "doc_id": "104246786", "n_citations": 408, "n_key_citations": 2, "score": 0, "title": "Highly Reproducible Sn Based Hybrid Perovskite Solar Cells with 9% Efficiency", "venue": "", "year": 2018 }, { "abstract": "Abstract The unknown LSMO/ZnO spin orbit dynamics and bandgap are presented by Mn partial wave state density of LaSrMnO3 and SRS spectroscopy. Raman active phonon in orthorhombic perovskite ZnO/La0.7Sr0.3MnO films are were focused by measuring Raman spectra in various scattering configurations. The LSMO spin state density is modified by Mn mixed valence state. The results show that the spin orbit is caused by anomalies tilt of MnO6 octahedron and electrons hopped into the empty orbital states. The transfer of d x 2 y 2 orbits dynamics is in the background of the ferro orbital order state of crystal stabilized d 3 z 2 r 2 orbit effect. The LSMO/ZnO displays magnetic and phononic scattering measurement. The kinetic energy gain achieved by the orbital competition, magnetic ordering, strong crystal field and charge order of energy band splitting. The LSMO/ZnO junction exhibits excellent junction antiferromagnetic/ferromagnetic phonon peaks and magnetoresistance behavior over the temperature range of 77 300 K. The significant energy band competition originates from the strong crystal splitting field and orbital canting.", "author_names": [ "Ren Ren", "Yijing Ren", "Xuan Li", "Lei Bai" ], "corpus_id": 137454153, "doc_id": "137454153", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Carrier transport spin orbit dynamics in surface enhanced Raman shift of perovskite films", "venue": "", "year": 2016 } ]

[ { "abstract": "A wafer scale, 2D organic single crystalline semiconductor revolutionizes near field communication. Two dimensional (2D) layered semiconductors are a novel class of functional materials that are an ideal platform for electronic applications, where the whole electronic states are directly modified by external stimuli adjacent to their electronic channels. Scale up of the areal coverage while maintaining homogeneous single crystals has been the relevant challenge. We demonstrate that wafer size single crystals composed of an organic semiconductor bimolecular layer with an excellent mobility of 10 cm2 V 1 s 1 can be successfully formed via a simple one shot solution process. The well controlled process to achieve organic single crystals composed of minimum molecular units realizes unprecedented low contact resistance and results in high speed transistor operation of 20 MHz, which is twice as high as the common frequency used in near field wireless communication. The capability of the solution process for scale up coverage of high mobility organic semiconductors opens up the way for novel 2D nanomaterials to realize products with large scale integrated circuits on film based devices.", "author_names": [ "Akifumi Yamamura", "Shun Watanabe", "Mayumi Uno", "Masato Mitani", "Chikahiko Mitsui", "Junto Tsurumi", "Nobuaki Isahaya", "Yusuke Kanaoka", "Toshihiro Okamoto", "Jun Takeya" ], "corpus_id": 13684624, "doc_id": "13684624", "n_citations": 142, "n_key_citations": 0, "score": 1, "title": "Wafer scale, layer controlled organic single crystals for high speed circuit operation", "venue": "Science Advances", "year": 2018 }, { "abstract": "This work describes the wafer scale standing growth of (002) plane oriented layers of WS2 and their suitability for use in self biased broad band high speed photodetection. The WS2 layers are grown using large scale sputtering, and the effects of the processing parameters such as the deposition temperature, deposition time, and sputtering power are studied. The structural, physical, chemical, optical, and electrical properties of the WS2 samples are also investigated. On the basis of the broad band light absorption and high speed in plane carrier transport characteristics of the WS2 layers, a self biased broad band high speed photodetector is fabricated by forming a type II heterojunction. This WS2/Si heterojunction is sensitive to ultraviolet, visible, and near infrared photons and shows an ultrafast photoresponse (1.1 ms) along with an excellent responsivity (4 mA/W) and a specific detectivity ~1.5 x 1010 Jones) A comprehensive Mott Schottky analysis is performed to evaluate the parameters of the device, such as the frequency dependent flat band potential and carrier concentration. Further, the photodetection parameters of the device, such as its linear dynamic range, rising time, and falling time, are evaluated to elucidate its spectral and transient characteristics. The device exhibits remarkably improved transient and spectral photodetection performances as compared to those of photodetectors based on atomically thin WS2 and two dimensional materials. These results suggest that the proposed method is feasible for the manipulation of vertically standing WS2 layers that exhibit high in plane carrier mobility and allow for high performance broad band photodetection and energy device applications.", "author_names": [ "Hong-Sik Kim", "Malkeshkumar Patel", "Joondong Kim", "Mun Seok Jeong" ], "corpus_id": 206475514, "doc_id": "206475514", "n_citations": 39, "n_key_citations": 0, "score": 0, "title": "Growth of Wafer Scale Standing Layers of WS2 for Self Biased High Speed UV Visible NIR Optoelectronic Devices.", "venue": "ACS applied materials interfaces", "year": 2018 }, { "abstract": "In this study, influence of both Si/H2 ratio and C/Si ratio on growth rate uniformity and carrier concentration uniformity of n type 4H SiC epitaxial films grown by high speed wafer rotation vertical CVD tool was investigated. It was found that changes in radial profile of the growth rate and the carrier concentration obtained by varying Si/H2 ratio showed quite similar behavior to those obtained by varying C/Si ratio. Such a similar trend would suggest that the distribution of local C/Si ratio near the wafer surface changes depending on total Si/H2 ratio similarly to total C/Si ratio. Additionally, by using this relationship, both the growth rate uniformity of 49.2 mm/h 1.78% (1.15% s/mean) and carrier concentration uniformity of 1.08 x1016cm 3 6.15% (3.40% s/mean) was achieved.", "author_names": [ "Yoshiaki Daigo", "Akio Ishiguro", "Shigeaki Ishii", "Hideki Ito" ], "corpus_id": 139219980, "doc_id": "139219980", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "High In Wafer Uniformity of Growth Rate and Carrier Concentration on n Type 4H SiC Epitaxial Films Achieved by High Speed Wafer Rotation Vertical CVD Tool", "venue": "", "year": 2018 }, { "abstract": "4H SiC homo epitaxial films were grown using a high speed wafer rotation vertical CVD tool, and effects of wafer rotation speed during initial temperature ramping before epitaxial growth were investigated. Also, the effects of conditions during growth of the highly doped buffer layer on both surface and PL defect densities were investigated. It was found that the wafer rotation speed during the temperature ramping has a large influence on the surface defect density of the films. Especially, triangles generated from small pits were considerably reduced in the samples grown at a higher wafer rotation speed during the temperature ramping. The phenomena could be explained as a result of suppressed interfacial reaction between down falls (DFs) and the wafer surface. Additionally, it was found that the density of basal plane dislocations (BPDs) on a drift layer is remarkably reduced by adjusting the C/Si ratio during growth of the buffer layer grown prior to the drift layer. By applying higher wafer rotation speed during the temperature ramping and optimizing the C/Si ratio for the growth of the buffer layer, a total defect density of 0.75 cm 2 on the film, which includes DFs, triangles, DF triangles, stacking faults (SFs) and BPDs, was achieved.", "author_names": [ "Yoshiaki Daigo", "Akio Ishiguro", "Shigeaki Ishii", "Hideki Ito" ], "corpus_id": 139701307, "doc_id": "139701307", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Reduction of Surface and PL Defects on n Type 4H SiC Epitaxial Films Grown Using a High Speed Wafer Rotation Vertical CVD Tool", "venue": "", "year": 2018 }, { "abstract": "A 1.2 V 20 nm 307 GB/s high bandwidth memory (HBM) DRAM is presented to satisfy a high bandwidth requirement of high performance computing application. The HBM is composed of buffer die and multiple core dies, and each core die has 8 Gb DRAM cell array with additional 1 Gb ECC array. At speed wafer level, a u bump IO test scheme and an adaptive refresh scheme considering temperature distribution are proposed to guarantee test coverage and stable operation in a power efficient manner.", "author_names": [ "Kyomin Sohn", "Won-Joo Yun", "Reum Oh", "Chi Sung Oh", "Seong-Young Seo", "Min-Sang Park", "Dong-Hak Shin", "Won-Chang Jung", "Sang-Hoon Shin", "Je-Min Ryu", "Hye-Seung Yu", "Jae-Hun Jung", "Hyunui Lee", "Seok-Yong Kang", "Young-Soo Sohn", "Jung Hwan Choi", "Yong-Cheol Bae", "Seong-Jin Jang", "G Y Jin" ], "corpus_id": 207783774, "doc_id": "207783774", "n_citations": 31, "n_key_citations": 11, "score": 0, "title": "A 1.2 V 20 nm 307 GB/s HBM DRAM With At Speed Wafer Level IO Test Scheme and Adaptive Refresh Considering Temperature Distribution", "venue": "IEEE Journal of Solid State Circuits", "year": 2017 }, { "abstract": "In this investigation, we describe a combined low coherence interferometric technique to measure the surface and thickness profiles of wafers at once with high speed. The measurement system consists of a spectrally resolved interferometer to provide and monitor the optical path difference between two incident beams of the optical source part and a low coherence scanning interferometer to measure the dimensions of wafers with significantly shortened scanning length. In the experiments, a silicon wafer and a sapphire wafer, of which both sides are polished, were used as targets of the measurement system for verification of the proposed system. As a result, the scanning length of the low coherence scanning interferometer was reduced from a few millimeters to a few hundreds of micrometers approximately 10 times. In addition, surface profiles of both sides and thickness profiles were simultaneously measured to reconstruct 3D shapes of wafers.", "author_names": [ "Hyo Mi Park", "Ki-Nam Joo" ], "corpus_id": 46851868, "doc_id": "46851868", "n_citations": 15, "n_key_citations": 0, "score": 0, "title": "High speed combined NIR low coherence interferometry for wafer metrology.", "venue": "Applied optics", "year": 2017 }, { "abstract": "This paper presents data on wafer fused 1550 nm vertical cavity surface emitting lasers (VCSELs) based on the active region and distributed Bragg reflectors (DBRs) grown by molecular beam epitaxy. VCSELs with a tunnel junction aperture diameter of <inline formula> <tex math notation=\"LaTeX\"$8~\\mu \\text{m} /tex math>/inline formula> show lasing at a threshold current density <inline formula> <tex math notation=\"LaTeX\"$j_{\\mathrm {th}<3$ /tex math>/inline formula> kA/cm² an output optical power of ~4 mW, and a 3 dB bandwidth of approximately 7 GHz at a 10 mA bias current. The devices demonstrate single mode continuous wave operation with the transverse side mode suppression ratio (SMSR) varying in the range of 40 45 dB up to roll over currents. The increase in mirror losses due to the etching of the top DBR makes the output optical power increase to 6 mW and causes the wall plug efficiency value to reach 20% but SMSR remains in the range of 40 45 dB. This also makes it possible to reduce both the photon lifetime and, as a result, the effect of damping and increase the modulation bandwidth to 9 GHz. The observed open and clear eye diagrams indicate that non return to zero operation is possible at bit rates of up to 30 Gbps without equalization or forward error correction. The high output optical power and modulation performance pave the way for the dense wavelength division multiplexing application of wafer fused 1550 nm VCSELs.", "author_names": [ "Andrey V Babichev", "Leonid Karachinsky", "Innokenty Novikov", "Andrey Gladyshev", "Sergey A Blokhin", "S Mikhailov", "Vladimir Iakovlev", "Alexei Sirbu", "Grzegorz Stepniak", "Lukasz Chorchos", "Jaroslaw Piotr Turkiewicz", "K O Voropaev", "A S Ionov", "Mikel Agustin", "Nikolay N Ledentsov", "Anton Yu Egorov" ], "corpus_id": 37790966, "doc_id": "37790966", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "6 mW Single Mode High Speed 1550 nm Wafer Fused VCSELs for DWDM Application", "venue": "IEEE Journal of Quantum Electronics", "year": 2017 }, { "abstract": "Wafer scale defect free planar III V nanowire (NW) arrays with ~100% yield and precisely defined positions are realized via a patterned vapor liquid solid (VLS) growth method. Long and uniform planar GaAs NWs were assembled in perfectly parallel arrays to form double channel T gated NW array based high electron mobility transistors (HEMTs) with DC and RF performance surpassing those for all field effect transistors (FETs) with VLS NWs, carbon nanotubes (CNTs) or graphene channels in plane with the substrate. For a planar GaAs NW array based HEMT with 150 nm gate length and 2 V drain bias, the on/off ratio (ION/IOFF) cutoff frequency (fT) and maximum oscillation frequency (fmax) are 10(4) 33, and 75 GHz, respectively. By characterizing more than 100 devices on a 1.5 x 1.5 cm(2) chip, we prove chip level electrical uniformity of the planar NW array based HEMTs and verify the feasibility of using this bottom up planar NW technology for post Si large scale nanoelectronics.", "author_names": [ "Xin Miao", "Kelson D Chabak", "Chen Zhang", "Parsian Katal Mohseni", "Dennis E Walker", "Xiuling Li" ], "corpus_id": 14479676, "doc_id": "14479676", "n_citations": 49, "n_key_citations": 1, "score": 0, "title": "High Speed Planar GaAs Nanowire Arrays with fmax 75 GHz by Wafer Scale Bottom up Growth.", "venue": "Nano letters", "year": 2015 }, { "abstract": "A new type of 150 mm vertical 4H SiC epitaxial reactor with high speed wafer rotation has been developed. Multiple resistance heaters ensure uniform radial temperature distribution throughout a 150 mm diameter wafer. Enhancement of the growth rates is realized by high speed wafer rotation under a relatively high system pressure, and growth rates of 40?50 ?m/h are achieved on 4? off 4H SiC substrates, maintaining a low defect density and a smooth surface without macrostep bunching. Excellent thickness and doping uniformities are simultaneously obtained for a 150 mm diameter wafer at a high growth rate of 50 ?m/h.", "author_names": [ "Hiroaki Fujibayashi", "Masahiko Ito", "Hideki Ito", "Isaho Kamata", "Masami Naito", "Kazukuni Hara", "Shoichi Yamauchi", "Kunihiko Suzuki", "Masayoshi Yajima", "Shin-ichi Mitani", "Suzuki Katsumi", "Hirofumi Aoki", "Koichi Nishikawa", "Takahiro Kozawa", "Hidekazu Tsuchida" ], "corpus_id": 97752289, "doc_id": "97752289", "n_citations": 23, "n_key_citations": 0, "score": 0, "title": "Development of a 150 mm 4H SiC epitaxial reactor with high speed wafer rotation", "venue": "", "year": 2014 }, { "abstract": "Laser trimming is used extensively to ensure accurate values of on chip precision resistors in the presence of process variations. Such laser resistor trimming is slow and expensive, typically performed in a closed loop, where the laser is iteratively fired and some circuit parameter (i.e. current) is monitored until a target condition is satisfied. Toward reducing this cost, we introduce a novel methodology for predicting the laser trim length, thereby eliminating the closed loop control and speeding up the process. Predictions are obtained from waferlevel spatial correlation models, learned from a sparse sample of die on which traditional trimming is performed. Effectiveness is demonstrated on an actual wafer of laser trimmed ICs.", "author_names": [ "Constantinos Xanthopoulos", "Ke Huang", "Abbas Poonawala", "Amit Nahar", "Bob Orr", "John M Carulli", "Yiorgos Makris" ], "corpus_id": 17258235, "doc_id": "17258235", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "IC laser trimming speed up through wafer level spatial correlation modeling", "venue": "2014 International Test Conference", "year": 2014 } ]

[ { "abstract": "This brief presents a current efficient fully integrated low dropout regulator (LDO) for system on a chip applications. A common gate error amplifier with high bandwidth and slew rate is proposed to reduce the output voltage spike and the response time of the LDO greatly. In addition, the loop employs a direct dynamic charging technique to enhance load transient responses by directly detecting voltage variations through a capacitive coupling high pass filter. The circuit has been implemented in a 0.35 mm standard complementary metal oxide semiconductor process and occupies an active chip area of 0.064 mm2. Experimental results show that it can deliver a load current of 100 mA at a dropout voltage of 150 mV. It only consumes a quiescent current of 7 mA at light loads and can recover within 0.15 ms, even under the maximum load current change. Consequently, a faster and more accurate capacitorless LDO can be achieved.", "author_names": [ "Xin Ming", "Qiang Li", "Ze-kun Zhou", "Bo Zhang" ], "corpus_id": 2694970, "doc_id": "2694970", "n_citations": 71, "n_key_citations": 6, "score": 1, "title": "An Ultrafast Adaptively Biased Capacitorless LDO With Dynamic Charging Control", "venue": "IEEE Transactions on Circuits and Systems II: Express Briefs", "year": 2012 }, { "abstract": "This paper presents the design of a low dropout voltage regulator which has a low area and power consumption, as well as an improved transient response. The area reduction is achieved by biasing the power transistor in the triode region. In addition, a dynamic bias network is used in order to reduce its settling time to 300ns for any change in the load current from 100uA to 100mA. The regulator is designed in a Silterra 0.18um standard CMOS technology and brings a regulated output voltage of 1.8V. All the circuit is biased with 2.3uA only at loads smaller than 1mA, and can recover within 0.3us for maximum load and input voltage changes. Moreover, the regulator does not need any external capacitor to guarantee its stability", "author_names": [ "Andres Amaya", "Hector Gomez", "Guillermo Espinosa" ], "corpus_id": 30910910, "doc_id": "30910910", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An area efficient high speed, fully on chip low dropout LDO voltage regulator", "venue": "", "year": 2015 }, { "abstract": "A fully on chip LDO for very fast load transient up to 15mA/nsec in 28nm FDSOI is presented. Proposed LDO capitalizes on technological boost given to on chip capacitance density and MOS current drives to implement conventional compensation technique without using off chip capacitor. Dominant output pole enables the LDO to achieve its superior load transient performance. Proposed LDO generates 1.0V output from a 1.6V input supply and has maximum output current capacity of 15mA. Simulated worst case PSR at 10kHz is 23dB and current efficiency is 93% at maximum load condition. Three such LDOs are combined to provide dedicated 1.0V supplies to dual lane USB cores and their PLL. Area including reference generator, three LDO and all on chip capacitances is 0.2mm2.", "author_names": [ "Saurabh Kumar Singh", "Gautam Dey Kanungo" ], "corpus_id": 2890202, "doc_id": "2890202", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Ultra fast Cap less LDO for Dual Lane USB in 28FDSOI", "venue": "2015 28th International Conference on VLSI Design", "year": 2015 }, { "abstract": "This brief presents an ultralow quiescent class AB error amplifier (ERR AMP) of low dropout (LDO) and a slew rate (SR) enhancement circuit to minimize compensation capacitance and speed up transient response designed in the 0.11 mm 1 poly 6 metal CMOS process. In order to increase the current capability with a low standby quiescent current under large signal operation, the proposed scheme has a class AB operation operational transconductance amplifier (OTA) that acts as an ERR AMP. As a result, the new OTA achieved a higher dc gain and faster settling time than conventional OTAs, demonstrating a dc gain improvement of 15.8 dB and a settling time six times faster than that of a conventional OTA. The proposed additional SR enhancement circuit improved the response based on voltage spike detection when the voltage dramatically changed at the output node.", "author_names": [ "Youngil Kim", "Sang-Sun Lee" ], "corpus_id": 5454373, "doc_id": "5454373", "n_citations": 74, "n_key_citations": 2, "score": 0, "title": "A Capacitorless LDO Regulator With Fast Feedback Technique and Low Quiescent Current Error Amplifier", "venue": "IEEE Transactions on Circuits and Systems II: Express Briefs", "year": 2013 }, { "abstract": "This paper presents an internally compensated capacitor less low dropout regulator (CL LDO) with bulk driven feed forward supply noise cancellation and adaptive compensation for fast settling time <italic>T_S/italic> A feed forward path from the CL LDO's supply input to the output is implemented to increase power supply rejection (PSR) from mid range frequencies to up to 5 MHz. The CL LDO achieves a 90 dB low frequency and 64 dB PSR at 1 MHz for 50 mA of load current <italic>I_L/italic> A transconductance amplifier with adaptive Miller compensation based on <italic>I_L/italic> sense is used to increase the unity gain frequency by 40x at heavy loads. The CL LDO achieves a 0.3 mV/V line regulation, 10 <italic>m</italic>V/mA load regulation, 300 ns of <italic>T_S/italic> and 0.16 ps figure of merit, which is 7.5x better than current state of the art CL LDOs. The CL LDO was fabricated in CMOS 130 nm technology, consumes <italic>I<sub>Q /sub>/italic> of 42 <italic>m</italic>A, has a dropout voltage <italic>V</italic>_DO of 200 mV for <italic>I_L/italic> of 50 mA, and occupies an active area of 0.0046 mm²", "author_names": [ "Fernando Lavalle-Aviles", "Joselyn Torres", "Edgar Sanchez-Sinencio" ], "corpus_id": 54438332, "doc_id": "54438332", "n_citations": 17, "n_key_citations": 2, "score": 0, "title": "A High Power Supply Rejection and Fast Settling Time Capacitor Less LDO", "venue": "IEEE Transactions on Power Electronics", "year": 2019 }, { "abstract": "hdykch mz y hn t`lTm y ld hb y l tlkhshm shn y drbrkh z shshwp `wnSm yh y lwt hb nrgshhwjp y d shshwp khrwkh yh y bT y y rb y rdhgn y dhG dwm yy hwym hlmj z zbs w h y h wr y hdrwa w dn y kh y ht `bnm z hyy a n GmS h g yh y h y .ts fdh shshwp rth shhwjp ny rd b yhd hnd GmS h y nHyr w wgnlb Swkh ykhrb w yrbn rm` rb kh yfykh w ym hwym wlh b yfdSt anlmkh HrT blq rd lyrwtkhf shymza khy rwZnm nydb .dsh ysrrb drs rbn rd yrdhgn yT s h .dsh mjn rrkht shwr rkh trwS hb hrmyt .dwb yrdrbn nmz w rmyt rwtkhf wd lmsh shymza rh 5 hqyqd hTwG hwym yrw hdma lwlHm rd h ymd b GmS hdsh 25 s hjrd ytn hwym ,ndsh khshkh z sp w dydrg lm` drg h hb ykhytslp fwrZ lqtn ymd rd w 5 hjrd swysls ybsn tbwTr w 90 dSrd dndsh yrdhgn nmz mwd rwtkhf b rbn rd yrdhgn 4 lmsh HTs 1 )yrdrbn `wrsh( 10 20 w 30 dwb na z d`b zwr z khy rh rd nmz yh hwym ,hdshrkhdh ,nlyt dylwt ,nwysrtyt lbq htydys ,lwlHm dmj dwm yhrtmrp w dndsh jrkh rbn z h m ,sfnt nzy w lkh lnf ysH ybyzr na rd .tfrg rrq ysrrb drwm h tn y j hkh dd nshn jytn bykhrt z hdfts hnd GmS h y nHyr w wgnlb yn`m rth kh rb yrd hwym sfnt nzym shh wlh drd S ymmt rb yrdrbn nmz rth ysrrb drwm tf rd wlh yn`m .dwb rd rtyt lbq htydys w shyzf hwym lnf w lwlHm dmj dwm ,yrdrbn nyp rd shhkh nwys tfy ygjyw z ykhrb rd yrdhgn nmz w hrmyt nyb lbqtm rth rd h wlh dnnm lbq htydys ,lwlHm dmj dwm t ,nwysrty nlyt w yn`m sfnt nzym .dwb rd tn y hj g y r y hn yy z hdfts ,jytn hb hjwt b 1 0 dSrd d GmS hn h y w wgnlb nHyr shshwp nwn` hb m hb y`ybT ykhrwkh yh hwym yrbn rm` shyzf w tyfykh ZfH rwZn wlh ym hySwt .dwsh", "author_names": [ "Escrito por", "C Sandoval" ], "corpus_id": 222408141, "doc_id": "222408141", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "H", "venue": "Saunders Comprehensive Veterinary Dictionary", "year": 2021 }, { "abstract": "An advanced smooth pole tracking technique for a low dropout (LDO) regulator with a ceramic capacitor is presented in this article. Normally, the dominant pole is at the output of an LDO and becomes load dependent, which may cause a loop stability issue during the whole load current application range. The proposed frequency compensation methodology with adaptive load resistor control of an error amplifier (EA) alleviates the problem and reduces the dependence of equivalent series resistance of an output capacitor. Moreover, combined with this compensation strategy, an ultrafast EA by utilizing a transconductance enhancement technique is proposed to greatly reduce output voltage spikes as well as response time of the LDO during transient. This circuit has been implemented in a 0.18 mm standard CMOS process and occupies an active chip area of 0.017 mm2. Experimental results show that it can deliver 150 mA load current at 200 mV dropout voltage. Good loop stability and transient responses are easily achieved without degrading other important LDO parameters.", "author_names": [ "Xin Ming", "Hua Liang", "Zhi-wen Zhang", "Yang-Li Xin", "Yao Qin", "Zhuo Wang" ], "corpus_id": 216332008, "doc_id": "216332008", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A High Efficiency and Fast Transient Low Dropout Regulator With Adaptive Pole Tracking Frequency Compensation Technique", "venue": "IEEE Transactions on Power Electronics", "year": 2020 }, { "abstract": "This article presents a low quiescent current output capacitorless quasi digital CMOS LDO regulator with controlled pass transistors according to load demands. The pass transistor of the LDO is broken up to two smaller sizes based on a breakup criterion defined here, which considers the maximum output voltage variations to different load current steps to find the suitable current boundary for breaking up. This criterion shows that low load conditions will cause more output variations and settling time if the pass transistor is used in its maximum size. Therefore, using one smaller transistor for low load currents, and another one larger for higher currents, is the best trade off between output variations, complexity, and power dissipation. The proposed LDO regulator has been designed and post simulated in HSPICE in a 0.35 um CMOS process to supply a load current between 0 100 mA while consumes 7.6 uA quiescent current. The results reveal 46% and 69% improvement on the output voltage variations and settling time, respectively.", "author_names": [ "Alireza Saberkari", "Herminio Martinez Garcia", "Eduardo Jose Alarcon Cot" ], "corpus_id": 6532881, "doc_id": "6532881", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quasi digital low dropout voltage regulators uses controlled pass transistors", "venue": "", "year": 2016 }, { "abstract": "In this paper a fully on chip, any capacitor stable linear voltage regulator (LVR) using sub unity gain positive feedback loop and NMOS pass element is presented. Sub unity gain of the loop decouples loop stability from output capacitance value thus realizing any capacitor stable regulator. Regulator is shown to be stable for wide range of output capacitance values from 1nF to 40mF. Regulator output settles i n 0.5ms with peak to peak voltage variation of 158mV for a load current step of 0 to 115mA in 0.14ms with 1nF output capacitance. Response becomes better for higher values of output capacitance. LVR generates 1.25V output from 1.6V input while using another 3.0V input supply and occupies 0.18mm2 in 65nm CMOS.", "author_names": [ "Saurabh Kumar Singh", "Nitin Bansal" ], "corpus_id": 35165943, "doc_id": "35165943", "n_citations": 3, "n_key_citations": 1, "score": 0, "title": "Any Capacitor Stable LVR Using Sub unity Gain Positive Feedback Loop in 65nm CMOS", "venue": "2015 28th International Conference on VLSI Design", "year": 2015 }, { "abstract": "In this paper, a fully integrated digitally assisted low dropout regulator (LDO) for a NAND flash memory system is proposed and verified using 500 nm I/O CMOS transistors. By combining an amplifier (AMP) based LDO with a comparator (CMP) based LDO, the proposed LDO achieves both fast load response in the transient state and accurate regulation in the steady state, which are advantages of the CMP based LDO and AMP based LDO, respectively. Moreover, loop frequency stability is satisfied in a wide range of load currents between 0 and 150 mA by using the simple structure of the <inline formula><tex math notation=\"LaTeX\"$g_{m}/tex math>/inline formula> boost cell to insert an auxiliary path. For an input voltage range of 2.3 3 V and an output voltage of 2.1 V, the measured output droop is 225 mV for a 150 mA load step in the load transition time of 20 ns with the total bias current of <inline formula><tex math notation=\"LaTeX\"$81\\\\mu \\rm{A}/tex math>/inline formula> The fabricated prototype chip occupies <inline formula><tex math notation=\"LaTeX\"$160\\\\times ,610\\\\mu \\rm{m}{2}/tex math> /inline formula> with an on chip output capacitor of 2 nF.", "author_names": [ "Kye-Seok Yoon", "Hyun-Sik Kim", "Wanyuan Qu", "Young-sub Yuk", "Gyu-Hyeong Cho" ], "corpus_id": 36869439, "doc_id": "36869439", "n_citations": 8, "n_key_citations": 1, "score": 0, "title": "Fully Integrated Digitally Assisted Low Dropout Regulator for a NAND Flash Memory System", "venue": "IEEE Transactions on Power Electronics", "year": 2018 } ]

[ { "abstract": "This Economic Letter focuses on productivity growth in one area of the economy: the retail trade industry. Although strong productivity growth is often associated with high tech industries (such as semiconductor manufacturing) the retail sector has enjoyed above average productivity growth and contributed significantly to the acceleration in productivity at the national level. In addition, the retail trade industry highlights the diverse forces involved in the evolution of productivity growth.", "author_names": [ "Mark Doms" ], "corpus_id": 166620680, "doc_id": "166620680", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Productivity growth and the retail sector", "venue": "", "year": 2004 }, { "abstract": "The U.S. retail trade sector underwent a massive restructuring and reallocation of activity in the 1990s with accompanying technological advances. Using a data set of establishments in that sector, we quantify and explore the relationship between this restructuring and reallocation and labor productivity dynamics. We find that virtually all of the labor productivity growth in the retail trade sector is accounted for by more productive entering establishments displacing much less productive exiting establishments. The productivity gap between low productivity exiting single unit establishments and entering high productivity establishments from large, national chains plays a disproportionate role in these dynamics.", "author_names": [ "Lucia S Foster", "John C Haltiwanger", "C J Krizan" ], "corpus_id": 16774135, "doc_id": "16774135", "n_citations": 591, "n_key_citations": 47, "score": 0, "title": "Market Selection, Reallocation, and Restructuring in the U.S. Retail Trade Sector in the 1990s", "venue": "The Review of Economics and Statistics", "year": 2006 }, { "abstract": "We develop a monopolistically competitive model of trade with firm heterogeneity in terms of productivity differences and endogenous differences in the \"toughness\" of competition across markets in terms of the number and average productivity of competing firms. We analyse how these features vary across markets of different size that are not perfectly integrated through trade; we then study the effects of different trade liberalization policies. In our model, market size and trade affect the toughness of competition, which then feeds back into the selection of heterogeneous producers and exporters in that market. Aggregate productivity and average mark ups thus respond to both the size of a market and the extent of its integration through trade (larger, more integrated markets exhibit higher productivity and lower mark ups) Our model remains highly tractable, even when extended to a general framework with multiple asymmetric countries integrated to different extents through asymmetric trade costs. We believe this provides a useful modelling framework that is particularly well suited to the analysis of trade and regional integration policy scenarios in an environment with heterogeneous firms and endogenous mark ups.", "author_names": [ "Gianmarco Ireo Paolo Ottaviano", "Marc J Melitz" ], "corpus_id": 6797333, "doc_id": "6797333", "n_citations": 2888, "n_key_citations": 320, "score": 0, "title": "Market Size, Trade, and Productivity", "venue": "", "year": 2005 }, { "abstract": "Several recent comparative studies have shown a labour productivity gap in respect of UK retailing when compared with other countries, notably France and the USA. This article seeks to identify, through an overview of existing data and related research, the extent to which retail productivity in the UK compares to global competitors and attempts to reach a consensus on the factors that determine retail productivity, while highlighting common performance measures for retailers and Government to use in measuring future productivity trends. Methods employed include a review of published studies; interviews with industry participants in the UK and a small number of leading retailers in the USA; and an analysis of a specially created database of the performance of over 200 US, UK and French retail companies. The authors find that it is unwise to draw definitive conclusions from aggregate international economic analyses of the sector; that a wide variety of efficiency indicators are employed by the sector in practice; and that there are significant differences in the structure, operating and regulatory environment for retailing in the UK which impose costs on retailers that are not necessarily incurred in other countries.", "author_names": [ "Jonathan Reynolds", "Elizabeth B Howard", "Dimitry Dragun", "Bridget Rosewell", "Paul Ormerod" ], "corpus_id": 14580074, "doc_id": "14580074", "n_citations": 102, "n_key_citations": 4, "score": 0, "title": "Assessing the Productivity of the UK Retail Sector", "venue": "", "year": 2005 }, { "abstract": "Economists have shown that large and persistent differences in productivity levels across businesses are ubiquitous. This finding has shaped research agendas in a number of fields, including (but not limited to) macroeconomics, industrial organization, labor, and trade. This paper surveys and evaluates recent empirical work addressing the question of why businesses differ in their measured productivity levels. The causes are manifold, and differ depending on the particular setting. They include elements sourced in production practices and therefore over which producers have some direct control, at least in theory as well as from producers' external operating environments. After evaluating the current state of knowledge, I lay out what I see are the major questions that research in the area should address going forward.", "author_names": [ "Chad Syverson" ], "corpus_id": 2468282, "doc_id": "2468282", "n_citations": 2280, "n_key_citations": 166, "score": 0, "title": "What Determines Productivity?", "venue": "", "year": 2010 }, { "abstract": "We explore the effect of computerization on productivity and output growth using data from 527 large U.S. firms over 19871994. We find that computerization makes a contribution to measured productivity and output growth in the short term (using 1 year differences) that is consistent with normal returns to computer investments. However, the productivity and output contributions associated with computerization are up to 5 times greater over long periods (using 5 to 7 year differences) The results suggest that the observed contribution of computerization is accompanied by relatively large and time consuming investments in complementary inputs, such as organizational capital, that may be omitted in conventional calculations of productivity. The large long run contribution of computers and their associated complements that we uncover may partially explain the subsequent investment surge in computers in the late 1990s.", "author_names": [ "Erik Brynjolfsson", "Lorin M Hitt" ], "corpus_id": 16630165, "doc_id": "16630165", "n_citations": 1020, "n_key_citations": 112, "score": 0, "title": "Computing Productivity: Firm Level Evidence", "venue": "Review of Economics and Statistics", "year": 2003 }, { "abstract": "The authors look at differences in the scope and depth of pro competitive regulatory reforms and privatization policies as a possible source of cross country dispersion in growth outcomes. They suggest that, despite extensive liberalization and privatization in the OECD area, the cross country variation of regulatory settings has increased in recent years, lining up with the increasing dispersion in growth. The authors then investigate empirically the regulation growth link using data that cover a large set of manufacturing and service industries in OECD countries over the past two decades and focusing on multifactor productivity (MFP) which plays a crucial role in GDP growth and accounts for a significant share of its cross country variance. Regressing MFP on both economywide indicators of regulation and privatization and industry level indicators of entry liberalization, the authors find evidence that reforms promoting private governance and competition (where these are viable) tend to boost productivity. In manufacturing the gains to be expected from lower entry barriers are greater the further a given country is from the technology leader. So, regulation limiting entry may hinder the adoption of existing technologies, possibly by reducing competitive pressures, technology spillovers, or the entry of new high technology firms. At the same time, both privatization and entry liberalization are estimated to have a positive impact on productivity in all sectors. These results offer an interpretation to the observed recent differences in growth patterns across OECD countries, in particular between large continental European economies and the United States. Strict product market regulations and lack of regulatory reforms are likely to underlie the relatively poorer productivity performance of some European countries, especially in those industries where Europe has accumulated a technology gap (such as information and communication technology related industries) These results also offer useful insights for non OECD countries. In particular, they point to the potential benefits of regulatory reforms and privatization, especially in those countries with large technology gaps and strict regulatory settings that curb incentives to adopt new technologies.", "author_names": [ "Stefano Scarpetta", "Giuseppe Nicoletti" ], "corpus_id": 12917367, "doc_id": "12917367", "n_citations": 1021, "n_key_citations": 58, "score": 0, "title": "Regulation, Productivity and Growth: OECD Evidence", "venue": "", "year": 2003 }, { "abstract": "The news that the early retirement trend has been reversed and current older workers plan to work past conventional retirement ages has been widely heralded. Managers have been encouraged to make adjustments to differences in job conditions that are important to older workers. We use social exchange theory and the norm of reciprocity as a framework for examining six dimensions of job quality for their impact on employee engagement among several groups of older and younger workers at different points in the cycle of their careers in a large retail setting. Employees (N 6047) were surveyed as part of a large scale research project. Exploratory factor analyses identified commonalities among 27 job quality variables and four reliable factors. Regression analyses estimated the relationship between four job conditions and employee engagement. Although the relative weights of the factors differed by career stage, the same factors: (1) Supervisor Support and Recognition; (2) Schedule Satisfaction; and (3) Job Clarity were significant predictors of employee engagement for all age groups; (4) Career Development was a predictor for all but the retirement eligible employees. Findings reveal the importance of recognizing age diversity among both young and old employees. Both theoretical and practical implications are discussed. Copyright (c) 2010 John Wiley Sons, Ltd.", "author_names": [ "Jacquelyn Boone James", "Sharon McKechnie", "Jennifer E Swanberg" ], "corpus_id": 145302008, "doc_id": "145302008", "n_citations": 201, "n_key_citations": 14, "score": 1, "title": "Predicting employee engagement in an age diverse retail workforce", "venue": "", "year": 2011 }, { "abstract": "The amount of data in our world has been exploding, and analyzing large data sets so called big data will become a key basis of competition, underpinning new waves of productivity growth, innovation, and consumer surplus, according to research by MGI and McKinsey's Business Technology Office. Leaders in every sector will have to grapple with the implications of big data, not just a few data oriented managers. The increasing volume and detail of information captured by enterprises, the rise of multimedia, social media, and the Internet of Things will fuel exponential growth in data for the foreseeable future.", "author_names": [ "J Manyika" ], "corpus_id": 166449414, "doc_id": "166449414", "n_citations": 4742, "n_key_citations": 335, "score": 0, "title": "Big data: The next frontier for innovation, competition, and productivity", "venue": "", "year": 2011 }, { "abstract": "There is considerable evidence that producer level churning contributes substantially to aggregate (industry) productivity growth, as more productive businesses displace less productive ones. However, this research has been limited by the fact that producer level prices are typically unobserved; thus within industry price differences are embodied in productivity measures. If prices reflect idiosyncratic demand or market power shifts, high \"productivity\" businesses may not be particularly efficient, and the literature's findings might be better interpreted as evidence of entering businesses displacing less profitable, but not necessarily less productive, exiting businesses. In this paper, we investigate the nature of selection and productivity growth using data from industries where we observe producer level quantities and prices separately. We show there are important differences between revenue and physical productivity. A key dissimilarity is that physical productivity is inversely correlated with plant level prices while revenue productivity is positively correlated with prices. This implies that previous work linking (revenue based) productivity to survival has confounded the separate and opposing effects of technical efficiency and demand on survival, understating the true impacts of both. We further show that young producers charge lower prices than incumbents, and as such the literature understates the productivity advantage of new producers and the contribution of entry to aggregate productivity growth.", "author_names": [ "Lucia S Foster", "John C Haltiwanger", "Chad Syverson" ], "corpus_id": 2291115, "doc_id": "2291115", "n_citations": 1988, "n_key_citations": 228, "score": 0, "title": "Reallocation, Firm Turnover, and Efficiency: Selection on Productivity or Profitability?", "venue": "", "year": 2005 } ]

[ { "abstract": "Semiconductor saturable absorber mirrors (SESAMs) are used to produce passively Q switched ultrashort pulsed lasers. Numerical modeling of physical effects of SESAM is required to effectively design this type of lasers. For this purpose, simulations are performed to study the dynamic behavior of Gauss modes, gain of modes and saturation of the saturable absorber mirror. The laser beam quality has to be good enough in order to avoid chaotic laser behavior. We extended our dynamic mode analysis (DMA) algorithm to calculate laser beam quality. This simulation technique is based on rate equations for a set of Gauss modes and population inversions. Gain of each mode can be calculated separately by solving the corresponding set of rate equations. We have assumed that the reflectivity of the mirror is spatially invariant in the SESAMs model. An additional rate equation is required to include the saturation of SESAM. This equation considers parameters such as modulation depth, saturation fluence and relaxation time. Simulation results show that our model can predict pulse energy and non chaotic behavior of the laser.", "author_names": [ "Christoph Pflaum", "Zhabiz Rahimi" ], "corpus_id": 121710527, "doc_id": "121710527", "n_citations": 0, "n_key_citations": 0, "score": 1, "title": "Modeling of semiconductor saturable absorber mirrors using dynamic mode analysis", "venue": "Photonics West Lasers and Applications in Science and Engineering", "year": 2013 }, { "abstract": "Experimental and theoretical results on the mode locking dynamics in vertical external cavity surface emitting lasers with semiconductor and graphene saturable absorber mirrors are reviewed with an emphasis on the role of nonequilibrium carrier effects. The systems are studied theoretically using a fully microscopic many body model for the carrier distributions and polarizations, coupled to Maxwell's equations for the field propagation. Pump probe measurements are performed with (sub 100 fs resolution. The analysis shows that the non equilibrium carrier dynamics in the gain quantum wells and saturable absorber medium significantly influences the system's response and the resulting mode locked pulses. The microscopic model is used to study the pulse build up from spontaneous emission noise and to determine the dependence of achievable pulse lengths and fluences on the amounts of saturable and non saturable losses and the optical gain. The change of the group delay dispersion (GDD) on the pump level is examined and the dependence of the pulse lengths on the total amount of GDD is demonstrated experimentally. Theory experiment comparisons are used to demonstrate the highly quantitative accuracy of the fully microscopic modeling.", "author_names": [ "Jorg Hader", "Maik Scheller", "Alexandre Laurain", "Isak Ragnvald Kilen", "Caleb W Baker", "Jerome V Moloney", "Stephan W Koch" ], "corpus_id": 126402112, "doc_id": "126402112", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Ultrafast non equilibrium carrier dynamics in semiconductor laser mode locking", "venue": "", "year": 2017 }, { "abstract": "This work presents an overview of a combined experimental and theoretical analysis on the manipulation of temporal localized structures (LSs) found in passively Vertical Cavity Surface Emitting Lasers coupled to resonant saturable absorber mirrors. We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures, also called localized pulses. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time dependent current landscape", "author_names": [ "Julien Javaloyes", "P Camelin", "M Marconi", "M Giudici" ], "corpus_id": 47558563, "doc_id": "47558563", "n_citations": 17, "n_key_citations": 1, "score": 0, "title": "Electrical addressing and temporal tweezing of localized pulses in passively mode locked semiconductor lasers", "venue": "2017 19th International Conference on Transparent Optical Networks (ICTON)", "year": 2017 }, { "abstract": "This work presents an overview of a combined experimental and theoretical analysis on the manipulation of temporal localized structures (LSs) found in passively Vertical Cavity Surface Emitting Lasers coupled to resonant saturable absorber mirrors. We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures, also called localized pulses. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time dependent current landscape.", "author_names": [ "Julien Javaloyes", "P Camelin", "M Marconi", "M Giudici" ], "corpus_id": 115566861, "doc_id": "115566861", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Electrical addressing and temporal tweezing of localized pulses in passively mode locked semiconductor lasers", "venue": "Applications of Optics and Photonics", "year": 2017 }, { "abstract": "In this study, time domain dynamic model of a mode locked two sections DBR laser was obtained. Sort duration and high power optical pulse generation from a semiconductor laser was examined by using obtained model. For this aim, while one of the laser sections was thought as reverse biased and so acted as a saturable absorber, other section thought as forward biased with a DC current and so acted as a gain section. A semiconductor laser biased this way can produce mode locked pulses by suitable adjusting of reverse bias and forward bias values and this method known as passive mode locking.", "author_names": [ "Caglar Duman", "Bulent Cakmak" ], "corpus_id": 59573514, "doc_id": "59573514", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Time Domain Dynamic Analysis of 1550nm Monolithic Two Sections Mode Locked MQW Laser", "venue": "", "year": 2015 }, { "abstract": "Lowering the output noise of short pulse lasers has been a long standing effort for decades. Modeling the noise performance plays a crucial role in isolating the noise sources and reducing them. Modeling to date has either used analytical or semianalytical implementation of dynamical methods or Monte Carlo simulations. The former approach is too simplified to accurately assess the noise performance in real laser systems, while the latter approach is too computationally slow to optimize the performance as parameters vary over a wide range. Here, we describe a computational implementation of dynamical methods that allows us to determine the noise performance of a passively mode locked laser within minutes on a desktop computer and is faster than Monte Carlo methods by a factor on the order of 10. We apply this method to characterize a laser that is locked using a fast saturable absorber for example, a fiber based nonlinear polarization rotation device and a laser that is locked using a slow saturable absorber for example, a semiconductor saturable absorbing mirror. (c) 2018", "author_names": [ "", "C F", "M R" ], "corpus_id": 201688402, "doc_id": "201688402", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Efficiently modeling the noise performance of short pulse lasers with a computational implementation of dynamical methods", "venue": "", "year": 2019 }, { "abstract": "Lowering the output noise of short pulse lasers has been a long standing effort for decades. Modeling the noise performance plays a crucial role in isolating the noise sources and reducing them. Modeling to date has either used analytical or semianalytical implementation of dynamical methods or Monte Carlo simulations. The former approach is too simplified to accurately assess the noise performance in real laser systems, while the latter approach is too computationally slow to optimize the performance as parameters vary over a wide range. Here, we describe a computational implementation of dynamical methods that allows us to determine the noise performance of a passively mode locked laser within minutes on a desktop computer and is faster than Monte Carlo methods by a factor on the order of 103. We apply this method to characterize a laser that is locked using a fast saturable absorber for example, a fiber based nonlinear polarization rotation device and a laser that is locked using a slow saturable absorber for example, a semiconductor saturable absorbing mirror.", "author_names": [ "Shaokang Wang", "Thomas F Carruthers", "Curtis R Menyuk" ], "corpus_id": 51246530, "doc_id": "51246530", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Efficiently modeling the noise performance of short pulse lasers with a computational implementation of dynamical methods", "venue": "", "year": 2018 }, { "abstract": "Vertical External Cavity Surface Emitting Lasers (VECSELs) have been used for mode locked operation by using a Semiconductor Saturable Absorber Mirror (SESAM) usually in the external cavity [1] but also integrated in the gain chip [2] Impressive progress has been achieved since the first demonstration of an SESAM mode locked VECSEL in terms of pulse duration, average optical power, and peak power. While the shortest pulses have been achieved with optically pumped active layers, electrically pumped structures are promising for a number of applications. A versatile and accurate, if fairly complex, delay differential theoretical model for mode locking in electrically pumping VECSELs based on the physical description of gain and SESAM chips has been presented [3] however only the linear cavity geometry has been studied. A somewhat different approach was taken in [4][5] where an experiment informed model representing the laser somewhat artificially as a sequence of gain, absorber, and dispersion elements in a unidirectional ring cavity (reminiscent of the classic Haus theory) was developed, and successfully reproduced the measured laser parameters in both pico and femtosecond regimes. In the current work, we present a somewhat simplified model based on the physical laser design as in [3] which however can accommodate realistic geometry, both linear and folded cavity. The model is applied to study different regimes of laser operation, including the possibility of colliding pulse mode locking at harmonics of the fundamental roundtrip frequency. As in [3] we base the derivation on the analysis of amplitudes of waves incident onto, and reflected from, elements of the laser cavity, using the amplitude of the field reflected from the \"bulk\" of the cavity as the dynamic variables for the description of light. Standard rate equations are used for carrier densities. In the case of a linear cavity the model is thus somewhat similar to that used in [3] though somewhat simplified. No matrices of the type used in [3] are needed to recalculate the dynamic variables in our simplified model. The use of phenomenological gain carrier density dependences and linewidth enhancement factors, while less rigorous than the simplified microscopic model of [3] enables relatively easy inclusion of polarization dependences, allowing double polarisation frequency comb generation to be simulated. In the case of a folded (Z type) cavity either the gain chip or the SESAM chip can be positioned \"inside\" the cavity. The dynamic variables in the case of the gain chip in the middle are the fields reflected from the bulk of the gain chip in the directions of the output mirror and the absorber chip, and from the bulk of the SESAM back to the gain chip In the case of the gain chip in the middle position, the difference in the dynamics of the saturation of the gain chip changes the pulse parameters and stability limits compared with the linear cavity, but there is no qualitative difference. In the case of the absorber section in the intracavity position, colliding pulse dynamics was simulated with a rational relation between the delay times. Further results will be presented at the conference. References [1] U. Keller, A. C. Tropper, Phys. Reports, 429, 67 (2006) [2] D.J.H.C. Maas et al. Appl Phys B, 88, 493 (2007) [3] J. Mulet and S. Balle, IEEE J. Quantum Electron. 41, 1148 (2005) [4] M. Hoffmann et al. Opt. Express 18, 10143 (2010) [5] O.Sieber et al. Appl.Phys.B. 113, 133 145 (2013)", "author_names": [ "Eugene A Avrutin", "Krassimir Panajotov" ], "corpus_id": 126257106, "doc_id": "126257106", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Modelling dynamics of high bit rate mode locked VECSELs with different cavity geometries (Conference Presentation)", "venue": "", "year": 2018 }, { "abstract": "Laser self pulsing was a phenomenon exclusive to macroscopic lasers until recently, where self starting laser pulsation in a microscopic photonic crystal Fano laser was reported. In this paper a theoretical model is developed to describe the Fano laser, including descriptions of the highly dispersive Fano mirror, the laser frequency and the threshold gain. The model is based upon a combination of conventional laser rate equations and coupled mode theory. The dynamical model is used to demonstrate how the laser has two regimes of operation, continuous wave output and self pulsing, and these regimes are characterised using phase diagrams, establishing the regime of self pulsing numerically. Furthermore, the physics behind the self pulsing mechanism are explained in detail and it is demonstrated how cavity absorption makes the Fano mirror function as a saturable absorber, leading to Q switched pulse generation. A stability analysis is used to demonstrate how the dominant mechanism of instability is relaxation oscillations becoming un damped. Finally the effect of varying key self pulsing parameters is investigated by characterisation of the change in self pulsing regions.", "author_names": [ "T S Rasmussen", "Yi Yu", "Jesper Mork" ], "corpus_id": 126002238, "doc_id": "126002238", "n_citations": 20, "n_key_citations": 5, "score": 0, "title": "Theory of Self pulsing in Photonic Crystal Fano Lasers", "venue": "", "year": 2017 }, { "abstract": "Diamonds approaching the nanoscale have the potential for use as probe materials as their optical properties can be sensitive to optical/electric fields, mechanical stress/ pressure, and the configuration of nuclear spins. The surface of nanodiamonds impacts their optical properties and sensing capabilities, and examining the nanodiamond surface through X ray absorption can give insights into molecular surface structures. Here, quantum dot models with varying amounts of surface carbon passivation are prepared, optimized, and compared. The loss of the diamond sp lattice is examined by investigating the bond length and tetrahedral character of the carbons comprising nanodiamonds for the appearance of aromatic sp surface domains. Electronic transitions in the carbon K edge region, using the energy specific time dependent density functional theory method, as well as vibrational spectra are computed from the optimized models. The surface reorganization is shown to affect the electronic characteristics of the nanodiamond. As a result, there is a distinct absorption peak in the carbon K edge region, along with stretching modes in the vibrational spectra, that can be correlated to the nature of the surface hybridization of the nanodiamond. INTRODUCTION Nanodiamonds are interesting materials due to their stability and potential for use in biological imaging, quantum computing, drug delivery, and sensing as a result of their lack of photobleaching, spin polarized photoluminescense, and long spin lifetimes when doped. Bulk, undoped diamonds are insulators with a band gap of approximately 5.5 eV. They are thus transparent to visible radiation; however, dopants such as the nitrogen vacancy and silicon split divacancy can lead to optical signatures in the visible region. These optical signatures can be tuned by altering the size of the nanocrystal. As the size of the nanocrystal decreases, discrete electronic states emerge at the band edges along with an energetic increment of the band gap as a result of the quantum confinement effect. In diamond, carbon is arranged into a highly symmetric, tetrahedral sp lattice. However, because of graphitic pre edge features that appear in the carbon K edge energy region of Xray and electron energy loss spectroscopy of nanodiamonds, it has been theorized that as diamond approaches the nanoscale the surface carbons arrange to form sp features. Earlier theories on the arrangement of the carbons predicted a diamond core with a graphitic shell around it. This model for describing the surface of the diamond still cannot describe an experimentally determined deviation from perfect lattice Bragg peaks. Thus, an improved model was proposed where nanodiamonds arrange themselves in a manner similar to that in Figure 1. In this model, there is an sp diamond core surrounded by a shell of sp carbon atoms where the diamond lattice deviates from its perfect tetrahedral arrangement, labeled S2 in the figure. Finally, this intermediate shell interacts with the graphitic, sp surface layer, labeled S1 in the figure. 25 Surface rearrangement, and thus the carbon hybridization, of nanodiamonds has been used to describe experimentally determined features on optical spectra, such as the carbon Xray absorption 285 eV pre edge. In the past few years, Received: January 12, 2018 Revised: March 8, 2018 Published: April 4, 2018 Figure 1. Proposed model for nanodiamond surface reorganization composed of a diamond lattice core, a layer of sp carbon where the diamond lattice deteriorates (S2) and the surface (S1) 1,25 Article pubs.acs.org/JPCC Cite This: J. Phys. Chem. C 2018, 122, 8573 8580 (c) 2018 American Chemical Society 8573 DOI: 10.1021/acs.jpcc.8b00354 J. Phys. Chem. C 2018, 122, 8573 8580 D ow nl oa de d vi a U N IV O F W A SH IN G T O N o n Ju ly 2 7, 2 01 8 at 1 9: 14 :4 8 (U T C Se e ht tp s: /p ub s. ac s. or g/ sh ar in gg ui de lin es f or o pt io ns o n ho w to le gi tim at el y sh ar e pu bl is he d ar tic le s. the effects of surface passivation, symmetry, and functionalization on the diamond lattice reorganization have also been studied computationally. However, a detailed understanding of the interplay between the surface rearrangement (i.e. sp moieties, graphitic and sp strained layers) and the presence of localized defects in the lattice (i.e. dopants) on the pre edge features that appear in the carbon K edge energy region of the X ray absorbance spectrum has still not been fully accomplished. Thus, in this study the effects of different surface hybridizations on the Raman scattering vibrational spectroscopy and X ray absorption are examined using a finite cluster approach combined with harmonic treatment and energy specific timedependent density functional theory (TDDFT) respectively. This technique has shown very promising results for the theoretical characterization of both the excited electronic states of defect containing semiconductor clusters and light elements and the vibrational/dynamical properties of molecules. Rearrangement of the surface carbon hybridization is predicted through the structural response to different surface passivations. Hydrogen was chosen to passivate the surface carbon dangling bonds, given that hydrogen surface termination can be realized experimentally using a hydrogen plasma process. Other moieties such as those containing oxygen and nitrogen are commonly found on the surface as a byproduct of the manufacturing and purification methods including the detonation of high explosives, a high pressure, high temperature multianvil press, and, most recently, laserheated diamond anvil cells (LH DAC) The unique use of noble gas pressure media during LH DAC processing maximizes the probability of graphitic surface reconstruction. In this work, density functional theory calculations are used with a cluster approach to find the optimized molecular geometry for the structures of varying surface passivations, as shown in Figure 2. This level of theory has already been used effectively to study nitrogen doped nanodiamonds of similar dimensions. To validate the predicted structural reorganization, infrared and Raman spectra have been calculated on systems with various degrees of surface passivation and compared with the experiments. The origins of the carbon Kedge pre edge feature motivated the study of the X ray absorption spectroscopy (XAS) in this energy region. XAS is elementally specific with large separations between the responses for different elements and gives information about weakly bound states to which it excites. Therefore, information about the surface hybridization can be determined through XAS. Since the molecular origin of the X ray pre edge feature for nanodiamonds is not fully understood, this theoretical study is motivated by a desire to understand the relationship between this feature and the surface arrangement in nanodiamonds. METHODOLOGY Nanodiamonds were constructed to be nearly spherical with a bulk fcc lattice parameter of a 0.357 nm according to the procedure presented in ref 11. Hydrogen atoms were used to passivate the surface carbon atoms and to saturate surface dangling bonds. Although other moieties are generally present on the surface, chemical treatments of the surface can provide a more uniform passivation. Before hydrogen removal or optimization, the diamonds have C3v symmetry, and two sizes, ~1.4 nm (C182H142) and ~1.2 nm (C121H104) in diameter, have been used throughout the article. These systems are similar, but slightly smaller, than commercially available nanodiamonds from laser heated diamond anvil cell synthesis or detonation synthesis. Given that the Bohr exciton radius for diamond is ~1.6 nm, the electronic properties of these diamond clusters are expected to exhibit quantum confinement effects. Calculations were preformed using the Gaussian electronic structure software package. The ground state electronic structures were obtained by solving the Kohn Sham equation using the hybrid Becke, three parameter, Lee Yang Parr (B3LYP) functional with a 6 31g(d) basis. The theory level employed has been previously validated for the description of the electronic structure and optical properties of both pure and nitrogen vacancy doped diamonds of the same dimensions. To examine the effects of the surface passivation on the diamond lattice as the surface becomes more unsaturated, hydrogens were removed from the surface and the resulting structure was fully optimized. This surface reorganization is analogous to what has been hypothesized to occur when nanodiamonds are synthesized within a laser heated diamond anvil cell that uses a noble gas (i.e. neon or argon) as the nearly hydrostatic pressure medium. Hydrogens were removed in such a way as to preserve the symmetry of the unoptimized structures and to obtain a homogeneous hydrogen density across the surface of the nanodiamond (Figure 2) To verify the structures returned from the optimization were true minima and to compute the vibrational frequencies, the second derivatives of the energy with respect to the Cartesian nuclear coordinates were calculated. Given the number of atoms and possible arrangements of the systems studied, there are several structures with similar bonding structures and degenerate energies that can result from the optimizations. To ensure that the optimized structures represent physically valid models, XAS and Raman vibrational spectra were computed and compared to the experimental results. In addition, a detailed analysis of the surface reorganization is presented, providing a comparison with previous computational studies on diamonds of similar sizes. The average computed properties over each optimized nanodiamond structure are similar and representative of the experimental data, suggesting that the results presented herein are valid. The XAS was calculated using time dependent density functional theory (TDDFT) within the linear response framework and i", "author_names": [ "Ryan A Beck", "Alessio Petrone", "Joseph M Kasper", "Matthew J Crane", "Peter J Pauzauskie", "Xiaosong Li" ], "corpus_id": 52218056, "doc_id": "52218056", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ect of Surface Passivation on Nanodiamond Crystallinity", "venue": "", "year": 2018 } ]

[ { "abstract": "Organic inorganic hybrid materials promise both the superior carrier mobility of inorganic semiconductors and the processability of organic materials. A thin film field effect transistor having an organic inorganic hybrid material as the semiconducting channel was demonstrated. Hybrids based on the perovskite structure crystallize from solution to form oriented molecular scale composites of alternating organic and inorganic sheets. Spin coated thin films of the semiconducting perovskite (C(6)H(5)C(2)H(4)NH(3)(2)SnI(4) form the conducting channel, with field effect mobilities of 0.6 square centimeters per volt second and current modulation greater than 10(4) Molecular engineering of the organic and inorganic components of the hybrids is expected to further improve device performance for low cost thin film transistors.", "author_names": [ "" ], "corpus_id": 5687231, "doc_id": "5687231", "n_citations": 1444, "n_key_citations": 11, "score": 1, "title": "Organic inorganic hybrid materials as semiconducting channels in thin film field effect transistors", "venue": "Science", "year": 1999 }, { "abstract": "Organic inorganic hybrid perovskite materials promise both the superior carrier mobility of inorganic semiconductors and the processability of organic materials, which make organic inorganic hybrid perovskite materials good substitutes in all the applications put forth for organic materials and extend their application to higher speed devices than is presently possible with either a Si or organic semiconductors. Recent reports have shown high carrier mobility and long electron hole diffusion lengths of organic inorganic hybrid perovskite materials. We have demonstrated a thin film field effect transistor with an organic inorganic hybrid CH3NH3PbI3 material as the semiconducting channel based on these advantages via a low temperature vapor assisted solution process. The obvious electrical field effect is obtained in organic inorganic hybrid CH3NH3PbI3 perovskite TFTs with a field effect mobility of 396.2 cm2 V 1 s 1, current modulation greater than 104, sub threshold current of 0.4035 V per decade and threshold voltage of 3.501 V.", "author_names": [ "Yuxiang Wu", "Juan Li", "Jian Xu", "Yangyang Du", "Like Huang", "Jian Ni", "Hongkun Cai", "Jianjun Zhang" ], "corpus_id": 49386052, "doc_id": "49386052", "n_citations": 46, "n_key_citations": 0, "score": 0, "title": "Organic inorganic hybrid CH3NH3PbI3 perovskite materials as channels in thin film field effect transistors", "venue": "", "year": 2016 }, { "abstract": "Abstract Thin film field effect transistors (TFTs) are an essential part of a variety of modern electronics. Interestingly, organic inorganic hybrid perovskite (OHP) material combines the excellent carrier mobility of inorganic semiconductors and the fabricability of organic materials. Herein a thin film field effect transistor using CH3NH3PbI3 as the semiconducting channel was demonstrated. A feasible strategy was presented by modifying the gold electrode with 4 fluorobenzenethiol to eliminate the hole injection barrier between the electrode and CH3NH3PbI3. In addition, we also improved the interfacial characteristics between the gold electrode and the perovskite film by using molybdenum oxide (MoO3) buffer layer. Finally, high k alumina (Al2O3) was utilized to substitute silicon oxide (SiO2) as the dielectric layer to reach low operating voltage in OHP TFTs. The representative TFT showed superior performance with the subthreshold swing (SS) on/off current ratio and linear field effect mobility (mFE) values of 0.49 V/dec, 104 and 21.41 cm2/V, respectively. Simple low temperature processing technology and prominent device performance made this OHP TFT have broad prospects for low cost, large area, and flexible applications. The device performance is supposed to be further enhanced through molecular engineering in the organic and inorganic components of the hybrid perovskite to fulfil high speed applications.", "author_names": [ "Juan Li", "Zhou-Kun Zhou", "Yuze Peng", "Jianjun Zhang", "Ning Guo", "Yanyan Sun" ], "corpus_id": 219035028, "doc_id": "219035028", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A novel TFT with organic inorganic hybrid perovskite channel layer", "venue": "", "year": 2020 }, { "abstract": "The structures, optical properties, and field effect mobilities of three semiconducting m fluorophenethylammonium based (C6H4FC2H4NH3)2SnI4 perovskites (m 2, 3, or 4) are reported and compared with the analogous measurements for the nonfluorosubstituted phenethylammonium system, (C6H5C2H4NH3)2SnI4. The (4 fluorophenethylammonium)2SnI4 system adopts a fully ordered monoclinic (P21/c) cell with the lattice parameters a 16.653(2) A, b 8.6049(8) A, c 8.7551(8) A, b 98.644(2)deg, and Z 2. Both (3 fluorophenethylammonium)2SnI4 and (2 fluorophenethylammonium)2SnI4 are refined in a monoclinic (C2/c) subcell with the lattice parameters a 34.593(4) A, b 6.0990(8) A, c 12.254(2) A, b 103.917(2)deg, and Z 4 and a 35.070(3) A, b 6.1165(5) A, c 12.280(1) A, b 108.175(1)deg, and Z 4, respectively. Each hybrid structure consists of sheets of corner sharing distorted SnI6 octahedra separated by bilayers of fluorophenethylammonium cations. The dominant low energy feature in the optical absorption", "author_names": [ "David B Mitzi", "and Christos D Dimitrakopoulos", "Laura L Kosbar" ], "corpus_id": 98311243, "doc_id": "98311243", "n_citations": 243, "n_key_citations": 2, "score": 0, "title": "Structurally Tailored Organic Inorganic Perovskites: Optical Properties and Solution Processed Channel Materials for Thin Film Transistors", "venue": "", "year": 2001 }, { "abstract": "DOI: 10.1002/aelm.201600218 In this study, we demonstrate solution processed In2O3 NWFETs for conventional bottom gate top contacts (BGTC structure) with a multiple nanowire network. Electrospinning is utilized to readily produce a scalable continuous In2O3 nanowire network. After an annealing process to remove the polymer matrix, the polycrystalline nanowire network exhibits a conductive channel property. To improve the FET performance, a bilayer structure comprising insulating zirconium oxide (ZrO2) and a nanowire network is adopted. Having a high binding energy with oxygen, ZrO2 is favorable for the passivation of oxygen related surface defects, firmly securing the nanowire network to the substrate. In addition, Lee et al.[5] reported that electrons can pass through several insulating oxides when those oxides are combined with a semiconducting buffer layer. ZrO2, specifically, has a low work function compared to those of other insulating oxides,[6] so it is often applied to injection layer in organic light emitting diodes or resistive memory layers in resistive random access memory.[7] With a ZrO2 top layer, NWFET performance shows high current on/ off ratio (Ion/Ioff) and field effect mobility (mFET) and small SS and Von. Apart from NWFETs, due to limitations of the analyses of nanowire/thin film structures, a bilayer with In2O3 thin film and ZrO2 is fabricated to investigate the conduction mechanism, which is based on the energy band structure. Figure 1a provides a schematic illustration of the fabrication process of the hybrid In2O3 nanowire/ZrO2 thin film FET. Using a conventional single nozzle electrospinning of indium nitrate/PVP solution, indium/poly(vinylpyrrolidone) (PVP) composite fibers are obtained in the form of a fiber mat onto a p+ Si/SiO2 (100 nm) substrate (Figure 2a) The substrate is used as gate/gate insulator. Subsequent thermal annealing on a hotplate at 400 degC results in an In2O3 nanowire network that adheres to the substrate (Figure 2b and Figure S1, Supporting Information) During thermal annealing, the decomposition of PVP reduces the size of the indium/PVP fiber and some of the fibers are welded spontaneously to form nodes and branches in the randomly oriented nanowire network. The ZrO2 top layer is coated directly on the nanowire network by a solution process using spin coating and annealing process. Finally, using e beam evaporation, the source and drain electrodes are deposited on top of the In2O3 nanowire/ZrO2 thin film composite (Figure S1, Supporting Information) The diameter of the indium oxide nanowires is a Gaussian distribution, in which the average size of 224 nanowires is 35.24 4.80 nm (see Figure S3, Supporting Information) All peaks in the X ray diffraction patterns in Figure 2c correspond to cubic In2O3 crystalline structure with Nanowire field effect transistors (NWFETs) are of great interest for future nanoelectronic application such as logic circuits, chemical/biosensors, and memory/display devices. Among various nanowire materials, indium oxide (In2O3) has received much attention because of its chemical stability, high mobility, and low temperature processibility. 1D nanowires featuring unique crystalline structure and distinctive carrier transport characteristics enable outstanding electrical performance.[1] However, when single nanowire is utilized for channel, its complicated growth and transfer processes are considered as an obstacle due to low yield and inconsistency in chemical and electrical properties. On the other hand, multiple nanowire networks have less deviation and enable more reliable device performance with higher yield, suggesting their great potential for electronic devices. Another issue in nanowires is that the substantial number of oxygen related surface states originating from the large surface to volume ratio results in high off current (Ioff) subthreshold swing (SS) turn on voltage (Von) and vulnerability to environmental stimuli. In this context, various studies have reported the passivation of oxide nanowires with organic or inorganic layers.[2] However, such a passivation process requires selective deposition steps including an additional patterning process. The stacking two heterogeneous metal oxide layers, a process frequently used to engineer a channel layer in a thin film transistor, is an attractive method to passivate the surface of a channel. In this bilayer structure, a top semiconducting layer such as InGaZnO, InZnO, or HfInZnO confines a conducting bottom layer and resulting devices demonstrate high mobility and robust gate bias stability.[3] However, this kind of confinement effect is valid only when the thickness of the bottom layer remains thin usually less than 5 nm; otherwise the channel becomes conductive and the device exhibits large negative Von and off current (Ioff) www.MaterialsViews.com www.advelectronicmat.de", "author_names": [ "Hyungjin Park", "Ki Ro Yoon", "Sungkyun Kim", "Il-Doo Kim", "Jungho Jin", "Yun Hyeok Kim", "Byeong-Soo Bae" ], "corpus_id": 114772997, "doc_id": "114772997", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Highly Conducting In2O3 Nanowire Network with Passivating ZrO2 Thin Film for Solution Processed Field Effect Transistors", "venue": "", "year": 2016 }, { "abstract": "Molecular atomic layer deposition (MALD) is employed to fabricate hydroquinone (HQ)/diethyl zinc (DEZ) organic inorganic hybrid semiconductor thin films with accurate thickness control, sharp interfaces, and low deposition temperature. Self limiting growth is observed for both HQ and DEZ precursors. The growth rate remains constant at approximately 2.8 A per cycle at 150 degC. The hybrid materials exhibit n type semiconducting behavior with a field effect mobility of approximately 5.7 cm2 V 1 s 1 and an on/off ratio of over 103 following post annealing at 200 degC in nitrogen. The resulting films are characterized using ellipsometry, Fourier transform infrared spectroscopy (FTIR) transmission electron microscopy (TEM) UV Vis spectroscopy, transistor behavior, and Hall effect measurements. Density functional theory (DFT) and many body perturbation theory within the GW approximation are also performed to assist the explanation and understanding of the experimental results. This research offers n channel materials as valuable candidates for efficient organic CMOS devices.", "author_names": [ "Jie Huang", "Hengji Zhang", "Antonio T Lucero", "Lanxia Cheng", "Santosh Kc", "Jian Wang", "Julia W P Hsu", "Kyeongjae Cho", "Jiyoung Kim" ], "corpus_id": 138636251, "doc_id": "138636251", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Organic inorganic hybrid semiconductor thin films deposited using molecular atomic layer deposition (MALD)", "venue": "", "year": 2016 }, { "abstract": "Hybrid organic/inorganic thin film transistors (TFTs) with bottom contact configuration were fabricated using the Laser Induced Forward Transfer (LIFT) process. The semiconducting polymer P3HT was laser printed from a donor to a receiver substrate in order to form the active layer of the TFTs. With a single laser pulse, P3HT pixels were successfully printed.The printed material was analyzed morphologically by means of Optical Microscopy and its thickness was measured by profilometry. In addition, structural characterization of P3HT thin films before and after laser printing took place by using UV Visible absorption spectroscopy and X Ray Diffraction. It was found that the crystallinity of the investigated films is improved upon annealing. An organic thin film transistor (OTFT) with laser printed P3HT pixel as a channel layer was then fabricated. The OTFTs indicated a field effect mobility up to 2.2310 4 cm2/Vs and an on/off ratio on the order of 10 100.", "author_names": [ "Marina Makrygianni", "Emanuele Verrelli", "Nikolaos Boukos", "Stavros Chatzandroulis", "Dimitris Tsoukalas", "Ioanna Zergioti" ], "corpus_id": 98036933, "doc_id": "98036933", "n_citations": 17, "n_key_citations": 0, "score": 0, "title": "Laser printing and characterization of semiconducting polymers for organic electronics", "venue": "", "year": 2013 }, { "abstract": "A bs or pt io n RT 120 170 200 250 300 350 400 Early research on polymer electronic devices successfully demonstrated function and performance adequate for specific applications. As a result, the performance of devices fabricated from semiconducting polymers has improved to the point where 'plastic' electronics are now expected to develop into a significant industry with a large market opportunity. However, the limited stability of polymer based devices continues to hinder the path toward commercialization. Because stability in air is critical to the commercialization of polymer electronic devices, discussions concerning the stability of semiconducting polymers have focused on degradation caused by reaction with oxygen and water vapor. Conjugated polymers are, however, generally believed to be incapable of withstanding high temperatures (i.e. temperatures well above the glasstransition temperature, Tg) [6,7] thus, stability at high temperatures has received less attention. The availability of semiconducting polymers that can survive exposure to elevated temperatures would open a variety of new possibilities. For example, since inorganic electronic devices typically require process steps that must be carried out at high temperature (often over 300 8C) semiconducting polymers capable of withstanding high temperatures will enable the fabrication of novel organic inorganic hybrid devices. Here, we report the remarkable stability of the poly(2,7carbazole) derivative, poly[N 900 hepta decanyl 2,7 carbazole alt5,5 (40,70 di 2 thienyl 20,10,30 benzothiadiazole) (PCDTBT; see the inset of Fig. 1a) Prior to this report, there was no known example of a semiconducting polymer that is both stable in air at (and above) room temperature and capable of withstanding high temperatures for extended periods of time. PCDTBT is one of a relatively large class of 'donor acceptor' polycarbazole co polymers. Recently, polymer bulkheterojuction solar cells fabricated with phase separated blends of PCDTBT and PC71BM were demonstrated with internal quantum efficiency approaching 100% power conversion efficiency of 17% in response to monochromatic radiation within the absorption band, and power conversion efficiency of 6.1% in response to solar radiation. To investigate the stability of PCDTBT, we have carried out spectroscopic studies on PCDTBT thin films and transport studies using the field effect transistor (FET) architecture with PCDTBTas the semiconductor material in the channel. Figure 1 shows UV visable (UV vis) absorption spectra of PCDTBT thin films annealed for 15 minutes at various temperatures in air (Fig. 1a) and under N2 atmosphere (Fig. 1b) In air, the p p* absorption spectrum is not affected after exposure to temperatures up to 150 8C. Under N2 atmosphere (Fig 1b) the electronic band structure of PCDTBT is stable after exposure to temperatures as high as 350 8C.", "author_names": [ "Shinuk Cho", "Jung Hwa Seo", "Sung Heum Park", "Serge Beaupre", "Mario Leclerc", "Alan J Heeger" ], "corpus_id": 37131960, "doc_id": "37131960", "n_citations": 155, "n_key_citations": 1, "score": 0, "title": "A thermally stable semiconducting polymer.", "venue": "Advanced materials", "year": 2010 }, { "abstract": "During the last 25 years there has been growing research effort in organic electronics to improve the semiconducting, conducting and light emitting properties of organic materials (polymers, oligomers) and hybrids (organic inorganic composites) through novel synthesis and self assembly techniques. Performance improvements, coupled with the ability to process these materials at low temperatures over large areas on flexible substrates such as plastic or paper, provide unique advantages, generate new applications and form factors to address the growing needs for pervasive computing and enhanced connectivity and autonomy. Electronics based on organics also gained importance because the down scaling of structures in polymer materials can be realized with alternative, comparatively simple and low cost techniques. For a successful introduction of polymer electronics into the market an increase of the performance of the key elements of logic circuitry, the thin film transistors, will be essential. The Joanneum Research Institute of Nanostructured Materials and Photonics now routinely manufactures organic thin film transistors (OFETs) with critical channel lengths of less than a micrometer using various nanoimprinting techniques (hot embossing, UV NIL) We also evaluate and demonstrate alternative concepts for structuring organic materials, which are implementable in electronic and optoelectronic applications. We reproducibly achieve high values for several OFET parameters such as the charge carrier field effect mobility in combination with threshold voltages below 5V and high on/off ratios. We have high control over the organic semiconductor (pentacene) thin film formation, having immediate impact on the excellent electronic parameters of our sub micron OFETs.", "author_names": [ "Gunther Leising", "Barbara Stadlober", "Ursula Haas", "Anja Haase", "Christian Palfinger", "Herbert Gold", "Georg Jakopic" ], "corpus_id": 137213674, "doc_id": "137213674", "n_citations": 32, "n_key_citations": 0, "score": 0, "title": "Nanoimprinted devices for integrated organic electronics", "venue": "", "year": 2006 }, { "abstract": "NOT AVAILABLE ORGANIC TRANSISTOR BASED LARGE SCALE INTEGRATED CIRCUITS. Ananth Dodabalapur, B. Crone, Y.Y. Lin, J. Rogers, Z. Bao, R. Filas, S. Martin, R. Sarpeshkar, H.E. Katz and W.J. Lee, Bell Laboratories, Lucent Technologies, Murray Hill, NJ. The performance characteristics of both p channel and n channel organic/polymeric thinlm transistors have reached a level that have enabled the design and experimental realization of large scale complementary integrated circuits. Successful design of such circuits requires a detailed understanding of the basic physics of operation of such transistors as well as the development or modi cation of a range of software tools. We will describe the DC, transient, and noise properties of transistors made with a number of organic and polymer semiconductors and the characteristics of circuits fabricated by a range of methods. We will also describe the advantages of complementary circuits for applications such as RF Tags. Organic transistors have also been integrated with display elements such as organic light emitting diodes. Design considerations and experimental results from such `smart pixels' will be outlined. THIN FILM ORGANIC INORGANIC FIELD EFFECT TRANSISTORS. C.R. Kagan, D.B. Mitzi, C.D. Dimitrakopoulos, L.L. Kosbar, IBM T.J. Watson Research Center, Yorktown Heights, NY. We report thinlm eld e ect transistors having organic inorganic hybrid materials as the semiconducting channels. Organic inorganic hybrids promise the high carrier mobilities of inorganic semiconductors, but may be deposited by low cost, low temperature solution processes common to organic materials. Organic inorganic perovskites, one subset of hybrid materials, self assemble from solution to form oriented, molecular scale composites of alternating inorganic perovskite sheets and organic layers. Spin coated polycrystalline thinlms of (C H C H NH SnI just one example of an organic inorganic perovskite, forms conducting channels with eld e ect mobilities of 0.6 cm /V sec and on o ratios of 10 The exibility in the chemistry and dimensionality of hybrid materials is exploited to prepare organic inorganic perovskites with alternate organic layers and inorganic frameworks. Tailoring the organic and inorganic components of the perovskites is expected to improve carrier mobility, current modulation, and stability of hybrid materials in thinlm transistors. CRYSTAL ENGINEERING OF NTCDI DERIVATIVES FOR HIGH MOBILITY ELECTRON TRANSPORT IN FETS. H.E. Katz, A.J. Lovinger, J. Johnson, C. Kloc, T. Siegrist, Bell Laboratories, Lucent Technologies, Murray Hill, NJ. Naphthalene 1,4,5,8 tetracarboxylic dianhydride (NTCDA) and its diimide derivatives (NTCDIs) possess moderate n channel eld e ect transistor (nFET) mobilities, observable only under an inert atmosphere. However, by appending suitable substituents on NTCDI nitrogens, 2 3 order of magnitude mobility increases are observed, to 0.1 cm2/Vs. Certain uorinated substituents confer su cient stability for nFET operation in air, and one of them a ords the unprecedented capability of solution nFET fabrication. Crystal structures reveal exceptionally favorable packing geometries. These compounds show the highest mobilities and on/o ratios yet reported for organic based nFETs. TRAPPING IN ORGANIC FIELD EFFECT TRANSISTORS. J.H. Schoen, Ch. Kloc, B. Batlogg, Bell Laboratories, Lucent Technologies, Murray Hill, NJ. Organic eld e ect transistors have reached a performance similar to a Si:H devices with mobilities in the order of 1 cm /Vs and on/o ratios of 10 However, thin lm devices often exhibit instabilities, like hysteresis e ects, threshold voltage shifts, or gate voltage dependent mobilities, during operation. It has been questioned whether this behavior is intrinsic to the organic materials or can be ascribed to extrinsic e ects, such as traps or grain boundaries. We have prepared single and polycrystalline eld e ect transistors based on pentacene and oligothiophenes using di erent insulators. The mobility in high quality single crystal devices increases with decreasing temperature following a power law, indicative of band like charge transport in delocalized states. However, trapping in the bulk semiconductor, at the semiconductor/insulator interface as well as at grain boundaries can signi cantly in uence the characteristics of the devices. Especially, the formation of a potential barrier at grain boundaries due to trapped charge gives rise to thermally activated and gate voltage dependent transport. Furthermore, charged trapping sites can migrate during device operation causing, e.g. threshold voltage shifts. However, these e ects were not observed in pure (intrinsic) single crystalline transistors. Stable operation in air for more than a month is demonstrated. SESSION S2: CONDUCTIVE POLYMERS Chair: Zhenan Bao Tuesday Morning, April 25, 2000 Metropolitan II (Argent) 9,10 ANTHRACENEDIYLIDENE DERIVATIVES: SYNTHESIS, REDOX CHEMISTRY, OPTOELECTRONIC AND STRUCTURAL PROPERTIES. Martin R. Bryce, Department of Chemistry, University of Durham, Durham, ENGLAND. We will present the synthesis of new 9,10 anthracenediylidene systems, especially those bearing 1,3 dithiole substituents, and demonstrate that they are versatile building blocks for redox active materials. We will discuss: (i) photoinduced charge transfer studies and structural properties of donor pi acceptor derivatives of this system [1] (ii) synthesis and properties of novel bridged redox active cyclophanes [2] (iii) structural studies on intermolecular CT complexes of new functionalised derivatives[3] e.g. with TCNQ; (iv) the synthesis and redox behaviour of dendritic polymers incorporating bis(1,3 dithiol 2 ylidene) 9,10 dihydroanthracene units. [1] M.R. Bryce, et al, Chem. Eur. J. 1998, 4, 2580 2592. [2] T. Finn, M.R. Bryce, A.S. Batsanov, J.A.K. Howeard, Chem. Commun. 1999, 1835 1836. [3] M.R. Bryce, et al, Eur. J. Org. Chem. 1999, in press. THE ORGANIC METAL: BASIC SCIENTIFIC BACKGROUND AND TECHNOLOGICAL APPLICATIONS. Bernhard Wessling, Ormecon Chemie, Ammersbek, GERMANY. A special form of polyaniline exhibits metallic properties, so it can be considered as an \\Organic Metal\" It will be shown in what aspects the premetallic powder form is di erent from other polyanilines known", "author_names": [ "Kris J Senecal", "Margaret A Auerbach", "Heidi L Schreuder-Gibson", "" ], "corpus_id": 133610881, "doc_id": "133610881", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "S Electrically Active Polymers Chairs", "venue": "", "year": 2000 } ]

[ { "abstract": "Abstract A new fundamental parameter model and calculation algorithm is presented for quantitative analysis for total reflection X ray fluorescence analytical technique. The model takes into consideration the geometrical parameters of the measuring set up, the energy distribution of the exciter X ray beam and its incidence angle to the surface of the sample holder. The numerical solution of this new model results the concentration of the sample elements. The system of equations of the fundamental parameter model involves the mathematical description of the excitation process in the sample layer and in the sample holder. The theoretical calibration for the quantitative determination of the sample elements is based on the numerical comparison of the measured and calculated X ray fluorescence signal of the pure silicon sample holder. For the numerical calculation computer code was created in order to solve numerically the model equations. The whole analytical procedure is a standard free method. The theoretical model and the complete numerical calculation was tested experimentally with standard solutions of K, Sc, V, Mn, Co, Ni and Cu elements, which were dripped onto high purity silicon wafer and dried before measurement. This standard free analytical procedure can be utilized in the semiconductor industry and in various total reflection X ray fluorescence analysis performed for investigations of environmental samples, natural waters, geological substances, foods and drinks.", "author_names": [ "Imre Szaloki", "Gabor Radocz", "Anita Gerenyi" ], "corpus_id": 150182579, "doc_id": "150182579", "n_citations": 6, "n_key_citations": 0, "score": 1, "title": "Fundamental parameter model for quantification of total reflection X ray fluorescence analysis", "venue": "Spectrochimica Acta Part B: Atomic Spectroscopy", "year": 2019 }, { "abstract": "Abstract The performance has been compared of two different quantification methods namely, the commonly used empirical quantification procedure and a fundamental parameter approach for determination of the mass fractions of elements in particulate like sample residues on a quartz reflector measured in the total reflection geometry. In the empirical quantification procedure, the spectrometer system needs to be calibrated with the use of samples containing known concentrations of the elements. On the basis of intensities of the X ray peaks and the known concentration or mass fraction of an internal standard element, by using relative sensitivities of the spectrometer system the concentrations or mass fractions of the elements are calculated. The fundamental parameter approach does not require any calibration of the spectrometer system to be carried out. However, in order to account for an unknown mass per unit area of a sample and sample nonuniformity, an internal standard element is added. The concentrations/mass fractions of the elements to be determined are calculated during fitting a modelled X ray spectrum to the measured one. The two quantification methods were applied to determine the mass fractions of elements in the cross sections of a peat core, biological standard reference materials and to determine the concentrations of elements in samples prepared from an aqueous multi element standard solution.", "author_names": [ "Wawro Dariusz", "Barbara Holynska", "Beata Ostachowicz" ], "corpus_id": 96039457, "doc_id": "96039457", "n_citations": 5, "n_key_citations": 0, "score": 1, "title": "A comparison of the performance of a fundamental parameter method for analysis of total reflection X ray fluorescence spectra and determination of trace elements, versus an empirical quantification procedure", "venue": "", "year": 1998 }, { "abstract": "Measurements of X ray fluorescence spectra versus grazing incident angles provide information on elemental composition as well as density and thickness of near surface layers. Calculations of fluorescence intensities are presented, which are used for the evaluation of data obtained by total reflection X ray fluorescence (TXRF) spectrometry. The calculation is based on a matrix formalism to account for standing wave phenomena due to transmission and reflection in layered material. For the determination of concentrations the model makes additional use of the fundamental parameter technique in order to include absorption and enhancement effects of the fluorescence radiation. On the basis of experimental data some capabilities of this nondestructive and contactless probing technique are presented.", "author_names": [ "U Weisbrod", "R Gutschke", "Joachim Knoth", "Heinrich Schwenke" ], "corpus_id": 95809777, "doc_id": "95809777", "n_citations": 76, "n_key_citations": 0, "score": 0, "title": "Total reflection X ray fluorescence spectrometry for quantitative surface and layer analysis", "venue": "", "year": 1991 }, { "abstract": "Total reflection X ray fluorescence analysis (TXRF) is a method for qualitative and quantitative analysis of trace elements. In general TXRF is known to allow for linear calibration typically using an internal standard for quantification. For small sample amounts (low ng region) the thin film approximation is valid neglecting absorption effects of the exciting and the detected radiation. However, for higher total amounts of samples deviations from the linear relation between fluorescence intensity and sample amount have been observed. The topic of the presented work is an investigation of the parameters influencing the absorption phenomenon. Samples with different total amounts of arsenic have been prepared to determine the upper limit of sample mass where the linear relation between fluorescence intensity and sample amount is no longer guaranteed. It was found that the relation between fluorescence intensity and sample amount is linear up to ~100 ng arsenic. A simulation model was developed to calculate the influence of the absorption effects. Even though the results of the simulations are not satisfying yet it could be shown that one of the key parameters for the absorption effect is the density of the investigated element in the dried residues.", "author_names": [ "C Horntrich", "Florian Meirer", "Christina Streli", "Peter Kregsamer", "Giancarlo Pepponi", "Norbert Zoeger", "Peter Wobrauschek" ], "corpus_id": 14253568, "doc_id": "14253568", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Influence of the sample morphology on total reflection X ray fluorescence analysis", "venue": "Powder Diffraction", "year": 2009 }, { "abstract": "Abstract A method for the determination of the concentrations of elements in particulate like samples measured in total reflection geometry is proposed. In the proposed method the fundamental parameters are utilized for calculating the sensitivities of elements and an internal standard is used to account for the unknown mass per unit area of a sample and geometrical constant of the spectrometer. The modification of the primary excitation spectrum on its way to a sample has been taken into consideration. The concentrations of the elements to be determined are calculated simultaneously with the spectra deconvolution procedure. In the process of quantitative analysis the intensities of all X ray peaks corresponding to K and L series lines present in the analyzed spectrum are taken into account. (c) 1997 Elsevier Science B.V.", "author_names": [ "Dariusz Wegrzynek", "Barbara Holynska" ], "corpus_id": 95587206, "doc_id": "95587206", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Fundamental quantification procedure for total reflection X ray fluorescence spectra analysis and elements determination", "venue": "", "year": 1997 }, { "abstract": "Abstract Despite the fact that Total Reflection X ray Fluorescence (TXRF) is becoming more and more popular as a quantification technique in analytical chemistry due to its simplicity and robustness, there are still some key aspects related to the sample preparation that need to be improved. In this work, the effect of different parameters is investigated: measurement time, carrier position, sample volume and sample drying time. The measurement time and the sample volume on the carriers mainly affect the recovery rate and relative standard deviation of the quantified metal from aqueous solutions. The most important parameters that play a fundamental role in the calibration of a TXRF machine such as choice of the standard element and concentration ratio between the analyte and the standard are discussed. Practical and easy guidelines for the correct preparation of aqueous samples are presented. These can be used by both less and more experienced TXRF users, interested in measuring metal ion concentrations in aqueous samples.", "author_names": [ "Sofia Riano", "Mercedes Regadio", "Koen Binnemans", "Tom Vander Hoogerstraete" ], "corpus_id": 100330491, "doc_id": "100330491", "n_citations": 33, "n_key_citations": 0, "score": 0, "title": "Practical guidelines for best practice on Total Reflection X ray Fluorescence spectroscopy: Analysis of aqueous solutions", "venue": "", "year": 2016 }, { "abstract": "Abstract Secondary ion mass spectrometry (SIMS) has been the most widely used technique for the measurement of dopant distribution in Si because of its ability of determining profile shape, junction depth, and dose with adequate depth resolution and detection limits. In the case of ultrashallow implants though, SIMS is going towards its intrinsic limits; in fact, initial transient width and native oxide induced matrix effects affect the measurement in the first nanometres where a relevant part of the dopant is confined. Therefore, complementary techniques able to give information on the dose and on the distribution in the first nanometres are required. In this work, total reflection X ray fluorescence analysis (TXRF) resolved in angle has been evaluated as a candidate, given its high sensitivity in the near surface region, its ability of a quantitative analysis, its multielement capability, and its nondestructiveness. Three arsenic implanted Si samples have been analysed by SIMS and TXRF. The SIMS measurements have been carried out by a magnetic sector instrument of new generation with a Cs primary beam and by monitoring negative secondary ions. The TXRF measurements were performed at beamline 6 2 of the Stanford Synchrotron Radiation Laboratory. For the fluorescence measurements, an absolute quantification by fundamental parameters and comparison with the Si fluorescence signal has been adopted. The TXRF dose determination showed good agreement with other techniques. TXRF could also evaluate the accuracy of the SIMS profile in the first nanometres.", "author_names": [ "Giancarlo Pepponi", "Christina Streli", "Peter Wobrauschek", "Norbert Zoeger", "Katharina Luening", "Piero A Pianetta", "D Giubertoni", "Mario Barozzi", "Massimo Bersani" ], "corpus_id": 93822256, "doc_id": "93822256", "n_citations": 20, "n_key_citations": 1, "score": 0, "title": "Nondestructive dose determination and depth profiling of arsenic ultrashallow junctions with total reflection X ray fluorescence analysis compared to dynamic secondary ion mass spectrometry", "venue": "", "year": 2004 }, { "abstract": "Abstract Polycapillary optics, consisting of bundles of narrow hollow glass channels, are regularly used in the field of (micro )X ray fluorescence (XRF) spectroscopy to focus X rays down to a microscopic spot while increasing the flux density of the beam on the sample. Polycapillaries guide X ray photons through multiple total reflection events, similar to how light is guided within optic fibers. Although the use of polycapillaries in XRF spectroscopy allows for fairly straightforward qualitative elemental analysis, fundamental parameter (FP) based quantification remains difficult due to the energy dependent photon transmission efficiency, focal size, acceptance, etc. of these optics. In order to predict the polycapillary and input beam parameter dependent beam forming properties, a multithreaded Monte Carlo based polycapillary X ray ray tracing code is presented. Apart from supporting photon ray tracing in 'ideal' straight, conical and ellipsoidal shaped polycapillary optics, it also allows for the simulation of photon propagation through arbitrarily shaped optics to account for small deviations from the ideal shape, as is often the case in real world examples. The current code allows for the simulation of so called 'leak events' where the probability of a photon traveling through a capillary wall is taken into account, and also includes support for photon beam polarization effects. The simulated results show good agreement with experimental results obtained at the BM26A beamline of the European Synchrotron Radiation Facility (ESRF, Grenoble, France) The (poly)capillary X ray ray tracing simulation code, called 'polycap' developed in the C language and with bindings for Python, is released under the GPLv3 license. The code is expected to assist in the quantification of (poly)capillary based X ray fluorescence spectroscopy and may yield additional insight into the manufacturing and development of polycapillary optics.", "author_names": [ "Pieter Tack", "Tom Schoonjans", "Stephen Bauters", "Laszlo Vincze" ], "corpus_id": 225303872, "doc_id": "225303872", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "An X ray ray tracing simulation code for mono and polycapillaries: Description, advances and application", "venue": "", "year": 2020 }, { "abstract": "This work illustrates the quantification of Fluorspar, it is commonly used during metallurgical operations as flux. In general practice it is quantified by conventional method for verification of mineralogy and grades by using 2 3 analysts and days respectively. By using conventional method analyst can estimate CaF2, CaO, SiO2, MgO and R2O3 (mixed oxides) except SrO, BaO, and P etc. due to trace low quantity. At present a new strategy opportunity has been developed for fast, less interfering and low cost for all type of CaF2 as pressed pellet by wavelength dispersive X ray fluorescence (WD XRF) For verification of such strategy, a series of calibration lines were established by certified reference materials (CRM's) and synthetic standards. Matrix effects were corrected by applied Fundamental Parameters (FP) model. In current methodology CaCO3 was calculated after analysis of total carbon (C) through Infra red combustion method. All estimations were done in dried samples after removal of moisture. CaF2 was calculated by applying mathematical formulation. The presence of CaCO3 instead of other carbonates like MgCO3, BaCO3, Na2CO3 and K2CO3 etc were confirmed by XRD, ATR FTIR, and Volatilization method as well as compared with conventional analysis results and results were validated by using ISO 17025 protocol. *Corresponding author: Naseem Akhter, People's Steel Mills Limited, Karachi, Sindh, Pakistan, Tel: 09202103362620599; E mail: [email protected] Received May 28, 2018; Accepted October 15, 2018; Published October 24, 2018 Citation: Akhter N, Mumtaz M, Hussain SS (2018) Quantification of Metallurgical Flux by Wavelength Dispersive X Ray Fluorescence. Chem Sci J 9: 195. doi: 10.4172/2150 3494.1000195 Copyright: (c) 2018 Akhter N, et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.", "author_names": [ "Naseem Akhter", "M Mumtaz", "Syed Sajid Hussain" ], "corpus_id": 105853417, "doc_id": "105853417", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Quantification of Metallurgical Flux by Wavelength Dispersive X Ray Fluorescence", "venue": "", "year": 2018 }, { "abstract": "Bromine has been recognized as a valuable indicator for paleoclimatic studies. Wavelength dispersive X ray fluorescence (WDXRF) and total reflection X ray fluorescence (TXRF) methods were applied to study the bromine distributions in lake sediment cores. Conventional WDXRF technique usually requires relatively large mass of a sediment sample and a set of calibration samples. Some analytical approaches were developed to apply WDXRF to small sediment core samples in the absence of adequate calibration samples with a known Br content. The mass of a sample to be analyzed was reduced up to 200 300mg and the internal standard method with correction using fundamental parameters was developed for Br quantification. TXRF technique based on the direct analysis of a solid suspension using 20mg of sediment sample by internal standard method was additionally tested. The accuracy of the WDXRF and TXRF techniques was assessed by the comparative analysis of reference materials of sediments, soil and biological samples. In general, good agreement was achieved between the reference values and the measured values. The detection limits of Br were 1mg/kg and 0.4mg/kg for WDXRF and TXRF respectively. The results of the Br determination obtained with different XRF techniques were comparable to each other and used for paleoclimatic reconstructions.", "author_names": [ "Galina V Pashkova", "T S Aisueva", "Alexandr L Finkelshtein", "Egor V Ivanov", "Alexander A Shchetnikov" ], "corpus_id": 11351081, "doc_id": "11351081", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Analytical approaches for determination of bromine in sediment core samples by X ray fluorescence spectrometry.", "venue": "Talanta", "year": 2016 } ]

[ { "abstract": "A software and a hardware system for artificial smell detection is described. It has been designed and implemented on a local CPU to detect and follow gradients of odor concentration. It is based on inorganic semiconductor sensors, but the method is also useful for organic sensors. When mounted on an autonomous platform it is used as a guide for robotic navigation.<ETX>", "author_names": [ "Rony Rozas", "Javier Molina Morales", "D Vega" ], "corpus_id": 22147679, "doc_id": "22147679", "n_citations": 79, "n_key_citations": 0, "score": 1, "title": "Artificial smell detection for robotic navigation", "venue": "Fifth International Conference on Advanced Robotics 'Robots in Unstructured Environments", "year": 1991 }, { "abstract": "In light of our field/s progress in making programming accessible to novices, we contemplate an even more ambitious goal: make AI accessible to all. The Cozmo robot by Anki is revolutionizing consumer and educational robotics through built in computer vision and artificial intelligence algorithms. Calypso is a scaffolded robot programming environment for Cozmo inspired by Microsoft/s Kodu Game Lab. Calypso allows novices to program with advanced features such as visual recognition of objects and faces, simultaneous localization and mapping (SLAM) landmark based navigation, and speech input. Like Kodu, Calypso emphasizes rule based programming with high level primitives such as \"see\" \"hear\" \"move toward\" and \"grab\" and it uses an Xbox game controller as its primary interface. User testing of Calypso has shown that children as young as eight can easily use it to program Cozmo. This demo will show off some of Calypso/s most striking features, including real time graphical display of the robot/s world map, object detection with OpenCV, and speech recognition. We will share a Calypso curriculum that can be adapted to students from primary school through undergraduates. The demo will conclude with a discussion of the changes coming in both K 12 and undergraduate robotics instruction as we move from simple control of servos to true vision guided mobile manipulators. For an advance look at Calypso, please see https:/Calypso.software.", "author_names": [ "David S Touretzky", "Christina Gardner-McCune" ], "corpus_id": 3449521, "doc_id": "3449521", "n_citations": 9, "n_key_citations": 2, "score": 0, "title": "Calypso for Cozmo: Robotic AI for Everyone (Abstract Only)", "venue": "SIGCSE", "year": 2018 }, { "abstract": "In the present scenario, a blind person is compelled to rely on another person and cannot travel independently to any place without the help of others. This project aims to develop a smart stick for the visually impaired people. The smart stick will include a GPS/GSM system and obstacle detection mechanism. The GPS system is used by the user to know the current location and also to notify his friend or relative about the current location. This could result in a better movement of the user. A voice module will be attached so that the stick can alert the user about the obstacles and the current location name whenever necessary. GSM is used to send the message about the current location to his friend or relative and the current location announcement which involves text to speech conversion is given to the user by the system. INTRODUCTION Visual impairment can limit people's ability to perform everyday tasks and can affect their quality of life and ability to interact with the surrounding world. Blindness, the most severe form of visual impairment, can reduce people's ability to perform daily tasks, and move about unaided. Good quality rehabilitation allows people with different degrees of visual impairment to fully profit from life, achieve their goals and be active and productive in today's society. Ample efforts have been made to aid the blind by innovating and improving technologies. According to [23] \"The emerging ethics of human centric GPS tracking and monitoring\" the main factors focused while tracking a person are privacy, accuracy and accessibility. By the introduction of a basic sensor, the provisions to the aid of blind people have remarkably increased. Many universities and companies like IBM have given a part of their focus to the development of aids for the blind people. Some of the popular ones are smart canes and obstacle sensors. Recent development includes self driving cars and smart glasses. In the last 30 years, various other strides that have been developed are the text or speech softwares and smartphone apps. Moreover the systems that are being developed on robotics and artificial intelligence will be very advantageous to them as well. One of the major factors in developing these technical aids is the compatibility with the user. He should not have trouble getting acquainted with the product. The features of the product should not be too difficult to use. Even the notification systems used to alert the blind should be comfortable and reliable. Another major factor is the cost of such products. Since they are already paying for treatments or other nursing cares, the price of the product should be in the range that is reasonable. Other feature of these products should be the durability. The users might not be able to charge the system. So, appropriate measure should be taken for it. To aid visually impaired and to provide a compact and complete solution, a smart stick can be developed which will include a GPS system, obstacle detection mechanism and an audio module, so that the stick can instruct the directions to the user. The obstacle detection mechanism is combined with navigation and location detection using GPS GSM and an audio module with Bluetooth transceiver to provide a better solution than the already existing solutions. The technologies we plan to use are sonar technology, GPS navigation, GSM network, voice recognition and notification. Sonar technology is used for obstacle detection. The principle of the system works in the way that the detector sends and receives a signal. Upon the reception of the signal, the distance is calculated using the time it took for the signal to reflect back. It is a simple procedure which works with the properties of electromagnetic waves. This is mainly used to find distances in various fields. [Thumma* 4(6) June, 2017] ISSN 2349 4506 Impact Factor: 2.785 Global Journal of Engineering Science and Research Management http: www.gjesrm.com (c) Global Journal of Engineering Science and Research Management [20] Obstacle detection is done by ultrasonic sensors attached to the stick. The sensors are selected to satisfy their criteria of sensor angle, distance and other parameters. When the sensors come across some obstacle, it sets off a voice announcement from the set of announcements already recorded, according to their semantics and alerts the person about the obstacle in the path. In order to reduce the noise and sound dissipation, an earpiece is attached to give the audio announcements. The GPS system is used to detect the current location and helps the user to reach the destination by announcing the current location name whenever required by the user and also in case of an emergency, the location of the blind person can be sent to a relative or friend via SMS. LITERATURE REVIEW Existing paper works and solutions related to GPS GSM, and Obstacle detection reveal that, so far, all these technologies have been implemented individually but not integrated for the cause of the blind. Obstacle Detection: In sonar technology, sound propagations is used to navigate communicate with or detect objects on or under the surface of the water, such as other vessels. This technology can be mainly divided into two typespassive and active. In passive sonar, when the vessels make sound, they listen to it. Active sonar is emitting pulses of sounds and listening for echoes. This is the mechanism we will be working with. This is primarily used for acoustic location tracking. Ultrasonic technology is always in research very deeply because of the vast different ideas it can harbor. Moreover, due to its technological breakthroughs in various applications, the sensor is incorporated more and more widely. Some of the applications of ultrasonic sensor are parking sensors, robot avoid obstacle, level detections and its applications in the toxic, harmful and corrosive environments. Ultrasonic sensors are very well used for sensing applications in the areas of engineering, physics and medicine. Smart walking stick for visually impaired [1] incorporates artificial vision and object detection integrated with GPS to enable the user to know about the environment for efficient navigation. Although it is an advanced technology, lack of voice recognition to input the destination is a disadvantage to this system. Obstacle Detection in Unfamiliar Indoor Environments [2] comprises of a Kinect unit, a Tablet PC, a microcontrol ler, IMU sensors, and vibration actuators. These vibrators minimize the reliance on audio instructions for avoiding obstacles. It can also guide the blind to reach a de sired destination (office/room/elevator) within an unfamiliar building with the help of RGB camera of Kinect unit,2 D printed codes, a compass sensor for orienting the user towards the next direction of movement, and synthesized audio instructions. The system is heavily equipped and needs complex and heavy computations and processing which lead to rise in costs and energy consumption. Enhancement of smart cane [3] talks about a method which uses a smart cane to detect and notify obstacles. The notification is done to the user with the help of his smart phone. The sensors in the cane detect the distance between both the user and the obstacle. It also uses a gsm module in the system to track his location. It also uses a trivial accelerometer to detect uneven topologies. This helps a great lot to avoid accidents. Only limitation is that every user should be equipped with a smartphone because the data from the sensors are collected by the phone. These data is then transferred to the user by the help of an earphone. Design and development of secure navigation system for visually impaired people [4] is an infrared based detecting system and it announces obstacles in the user's path. This system also gives the necessary guidelines for the user to avoid the obstacles. This notification is done by vitro tactile or sound feedback. In this system, a light weight sensor is attached to a head cap so that the user is informed about the obstacles near to the head area. This provides an advantage over the simple walking stick. Obstacle detection gadget for visually impaired people [5] obstacle detection system proposed is based on infrared and the output is provided by buzzers and vibrators. This system is used for indoor obstacle detection. [Thumma* 4(6) June, 2017] ISSN 2349 4506 Impact Factor: 2.785 Global Journal of Engineering Science and Research Management http: www.gjesrm.com (c) Global Journal of Engineering Science and Research Management [21] Enhanced independence free path detector to blind people using gsm has been proposed in [6] Infrared technology is used for shoulder width field view from knee to head level. This significantly increases the field of view, but the infrared rays are easily shielded which reduces the efficiency and effectiveness of the system. Blind Aid using Radio Frequency Identification (RFID) and Ultrasonic sensors [7] uses RFID technology and ultrasonic sensors to help in improved navigation, but RFID has its own constraints like interference and complexity due to RFID tagging of every object in the vicinity. GPS Navigation: Global positioning system is defined to be a network of satellites that are orbiting around the earth. These satellites send accurate details of their position in space back to earth. These signals are received by the GPS receivers. Some of the GPS receivers include navigation devices. This gps technology was first introduced by the US for its military purposes in the global intelligence efforts for the Cold War. But after 1980s, GPs has been made available to everyone who owned a GPS receiver. Since then it has been mainly used for location tracking. Application of GPS is categorized as location, navigation, timing, mapping, and tracking. Each category contains its single or combined uses in the fields of military, recreation, transportation and science. T", "author_names": [ "Chandni Asvitha Thumma", "Shravya Amarnath", "Hanna Philipose" ], "corpus_id": 36235254, "doc_id": "36235254", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "LOCATION BASED NAVIGATION AND OBSTACLE DETECTION SYSTEM WITH VOICE ALERTS FOR BLIND", "venue": "", "year": 2017 }, { "abstract": "In this work, an implementation of a monimalist autonomous robotic agent with advanced navigation abilities was done. These abilities rely on specialised architectures based on artificial neural networks. It is intended to show that a comparatively simples robot platform with cheap components, is able to perform complex navigation tasks such as dead reckoning (navigation through spatial intuition) landmark circumvention and corresponding discrimination/ recognition, and efficient map construction and use for future navigation with shortcuts/ detours. Shaft encoders are used for the implementation of a coarse internal compass, whereas infra red sensors are used for ladmark detection and circumvention. The involved neural networks incorporate space as well as time information. Before doing the final implemnetation, an initial bibliographic research allowed to know the state of art in this field of navigation in autonomous agents.", "author_names": [ "Pedro Kulzer" ], "corpus_id": 112723470, "doc_id": "112723470", "n_citations": 2, "n_key_citations": 1, "score": 0, "title": "NAVBOT: Autonomous Robotic Agent with Neural Learning of Autonomous Mapping and Navigation Strategies", "venue": "", "year": 1997 }, { "abstract": "The aim of the work presented in this article is to develop a navigation system that allows a mobile robot to move autonomously in an indoor environment using perceptions of multiple events. A topological navigation system based on events that imitates human navigation using sensorimotor abilities and sensorial events is presented. The increasing interest in building autonomous mobile systems makes the detection and recognition of perceptions a crucial task. The system proposed can be considered a perceptive navigation system as the navigation process is based on perception and recognition of natural and artificial landmarks, among others. The innovation of this work resides in the use of an integration interface to handle multiple events concurrently, leading to a more complete and advanced navigation system. The developed architecture enhances the integration of new elements due to its modularity and the decoupling between modules. Finally, experiments have been carried out in several mobile robots, and their results show the feasibility of the navigation system proposed and the effectiveness of the sensorial data integration managed as events.", "author_names": [ "Clara Gomez", "Alejandra Carolina Hernandez", "Jonathan Crespo", "Ramon Barber" ], "corpus_id": 63835464, "doc_id": "63835464", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "A topological navigation system for indoor environments based on perception events", "venue": "", "year": 2016 }, { "abstract": "Scene Understanding has been a major aspiration of computer vision from its early days. Its root lies in enabling the computer/robot/machine to understand, interpret and manipulate visual data, in similarity to what an average human eye does in front of a natural/artificial localized location/scene. This ennoblement of the machine have a widespread impact ranging from Surveillance, Aerial Imaging, Autonomous Navigation, Smart Cities and thus scene understanding have remained as an active area of research in the last decade. In the last decade, the scope of problems in the scene understanding community has broadened from Image Annotation, Image Captioning, Image Segmentation to Object Detection, Dense Image Captioning, Instance Segmentation etc. Advanced problems like Autonomous Navigation, Panoptic Segmentation, Video Summarization, Multi Person Tracking in Crowded Scenes have also surfaced in this arena and are being vigorously attempted. Deep Learning has played a major role in this advancement/development. The performance metrics in some of these tasks have more than tripled in the last decade itself but these tasks remain far from solved. Success originating from deep learning can be attributed to the learned features. In simple words, features learned from a Convolutional Neural Network trained for annotation are in general far more suited for captioning then a non deep learning method trained for captioning. Taking cue from this particular deep learning trend, we dived into the domain of scene understanding with the focus on utilization of prelearned features from other similar domains. We focus on two tasks in particular: Automatic (multi label)Image Annotation and (Road)Intersection Recognition. Automatic image annotation is one of the earliest problems in scene understanding and refers to the task of assigning (multiple) labels to an image based on its content. Whereas intersection recognition is the outcome of the new era of problems in scene understanding and it refers to the task of identifying an intersection from varied viewpoints in varied weather and lighting conditions. We focused on this significantly varied task approach to broaden the scope and generalizing capability of the results we compute. Both image annotation and intersection recognition pose some common challenges such as occlusion, perspective variations, distortions etc. While focusing on the image annotation task we further narrowed our domain by focusing on graph based methods. We again chose two different paradigms: a multiple kernel learning based non deep learning approach and a deep learning based approach, with a focus on bringing out contrast again. Through quantitative and qualitative results we show slightly boosted performance from the above mentioned paradigms. The intersection recognition task is relatively new in the field. Most of the work in field focuses on Places Recognition which utilized only single images. We focus on temporal information i.e. the traversal of the intersection/places as seen from a camera mounted on a vehicle.", "author_names": [ "Abhijeet Kumar", "Avinash Sharma" ], "corpus_id": 214715161, "doc_id": "214715161", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "DEEP LEARNING FEATURES, GRAPHS AND SCENE UNDERSTANDING", "venue": "", "year": 2020 }, { "abstract": "Last years have seen a worldwide lengthening of life expectancy [1] and, as a consequence, an increment of advanced assistive solutions for integrated care models. In this context, ICT can enhance home assistance services for elderly people and thus, the economical burden for health care institutions. Indeed, recent studies report that 89% wish to stay at home for sentimental reasons or because they cannot afford nursing homes [2] In addition, the shortage of professional caregivers is a well known issue and relatives or friends must face with emotional distress negatively impacting also their productivity at work [3] In this perspective, home robots will play a crucial role. Not only they will keep their house safe by monitoring and detecting anomalies or sources of hazards but they can also be companions able to enhance their social life, e.g. by better connecting them with their relatives and friends. Examples of recent projects that have tried to develop such a kind of systems are Hobbit [4, 5] Astro [6, 7] and Giraffplus [8] The difficulties in creating a robust and reliable prototype and the encountered challenges in computer vision and autonomous robotics have been well explained in [5] This work aims at presenting an open source and practical solution for an autonomous robotic platform for home care. The final goal is to develop a set of artificial intelligence services for indoor autonomous and safe navigation, fall detection, people recognition, speech interaction and telepresence. In Section 2 and 3 respectively, the prototype and the tasks currently implemented are described. We have developed these functions in ROS: Robot Operating System [9] which provides many algorithms and a standard communication framework. The need for standards and open solutions have been already pointed out in [10] Future works are reported in Section 4: this project enables research in many fields like scene understanding, human robot interaction, socially assistive/intelligent robotics and sensor integration.", "author_names": [ "Marco Carraro", "Morris Antonello", "Luca Tonin", "Emanuele Menegatti" ], "corpus_id": 9052536, "doc_id": "9052536", "n_citations": 9, "n_key_citations": 1, "score": 0, "title": "An Open Source Robotic Platform for Ambient Assisted Living", "venue": "AIRO@AI*IA", "year": 2015 }, { "abstract": "This special issue of the journal features selected works presented at the 15th International Conference on Advanced Robotics (ICAR 2011) held in Tallinn, Estonia, in June 2011. The ICAR conference series is the oldest robotics conference and it celebrated its 30th anniversary in Tallinn. The theme of the ICAR 2011 conference, new boundaries for robotics, emphasized the forwardlooking spirit of its founders and the transformative nature of robotics research over time. Robotics is a synergistic technology, absorbing discoveries and inventions from various fields of science and technology. Taking inspiration from other disciplines we are able to build new kinds of robots that are better able to serve humans in novel ways. The selection of eight papers in this special issue illustrates the synergistic and transformative nature of robotics research by bringing to you the best examples from different sub fields of robotics presented at ICAR 2011. The subjects of these papers span advances in sensors, actuators, computer vision, and robot navigation and control. A brief introduction to these papers follows. Chanthasopeephan, Jarakorn, Polchankajorn, and Maneewarn present a novel solution for the mechanical design of a mobile robot in their paper, 'An impact reduction mobile robot and the design of compliant legs' Motivated by the need to for the robot to survive under impact conditions in practical applications such as search and rescue, the authors investigated an impact reduction mechanism based on the design of compliant legs. In addition, their robot is able to transform between different configurations depending on the terrain conditions; specifically, the legs are extended into awalkingmechanism on uneven terrainwhile being retracted to allow rolling on uneven terrain. Such a design makes it possible to design more reliable and robust robots for traversing difficult outdoor environments. The next three papers dealwith advanced sensors and actuators that are of great relevance to dexterousmanipulation, among other applications. In their paper, 'Detection and prevention of slip using sensorswith different properties embedded in elastic artificial skin on the basis of previous experience' Shirafuji andHosoda describe an approach to safe object grasping using an elastic artificial skin embedded with two kinds of embedded sensors: polyvinylidene fluoride (PVDF) thin films and strain gages. The PVDF sensors are used to detect slip on the basis of measured pressure changes while the strain gages provide the input to a neural network that controls the grasping force. The authors demonstrate that an anthropomorphic human scale hand equipped with these sensors is able to adapt the grasp to securely hold an object without an excessive force.", "author_names": [ "Maarja Kruusmaa", "Xiaobo Tan", "Cecilia Laschi", "Paolo Fiorini", "Raj Madhavan" ], "corpus_id": 3045316, "doc_id": "3045316", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Guest editorial: New boundaries for robotics", "venue": "Robotics Auton. Syst.", "year": 2014 }, { "abstract": "ourproject encompasses a study on the development of a walking gait for fault tolerant locomotion in unstructured environments.Quadra pod is a four legged walking robot. It should be a micro robot and designed with manual control. It consists of hardware and software. Thus the parts contain arduino Nano (ATMEGA 328) servomotor, ultrasonic sensor, PIR sensor and wireless module. An algorithm is developed for focusing mainly on efficient navigation method for locomotion, which will make it faster and at the same time energy efficient to navigate. The duplex communication included in the quadrapod helps in human interface with the bot for finding current position and to control. The scanning area of the robot is controlled by the matrix environment software and the path of the walking quadrapod robot is as shown in MATLAB GUI interface. This robot is used to detect the human in the disaster environment and also for detecting obstacles. Human motion detection and tracking is one of the main problems in computer vision field. It includes many advanced technology in different fields such as pattern recognition, automatic control, artificial intelligence, computer technology. At the same time this robot is used for life detection and obstacle detection. KeywordsArduino Nano(ATMEGA328) Ultrasonic Sensors, PIR (pyro electric Infrared Sensor) MATLAB GUI (Graphical User Infrared)", "author_names": [ "Vijay Mahadevan", "J Josephine Dhivya", "T R Monisha", "J Geetha", "R Divya" ], "corpus_id": 38225447, "doc_id": "38225447", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "OBJECT DETECTION AND PATH TRACKING USING QUADRAPOD ROBOT IN UNKNOWN ENVIRONMENT", "venue": "", "year": 2016 }, { "abstract": "Intelligent transportation systems, accessible data, wireless communications, mobile computing, robotics, artificial intelligence, and object detection navigation offer many possibilities for increasing mobility and independence. This article describes how Federal Highway Administration (FHWA) researchers are working on a suite of new technologies that have the potential to improve the lives of people with disabilities, senior citizens, and other members of the traveling public. Designing wayfinding, orientation, and guidance technologies into personal vehicles, public transport systems, ticketing and travel information mechanisms, terminals, intersections, and pedestrian infrastructure can enhance the experience of traveling for everyone including those with special needs. The FHWA's Exploratory Advanced Research Program, which focuses on long term, high risk research with a high payoff potential, is soliciting research and innovations to develop futuristic concepts and prototypes that use new technologies such as robotics, artificial intelligence, and sensors to improve event horizons related to wayfinding and navigation guidance. The hope is that the research will eventually generate a transportation system that is well connected, versatile, and accessible to everyone.", "author_names": [ "Mohammed Yousuf", "Mark Fitzgerald" ], "corpus_id": 107225510, "doc_id": "107225510", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "The New Frontier in Accessible Transportation", "venue": "", "year": 2012 } ]

[ { "abstract": "Existing bridgeless boost (BLB) converter with soft switching utilize more than two active switches and extra resonant networks. In this paper, a new zero current switching BLB rectifier with high power factor (PF) using only two active switches is proposed. The proposed BLB converter is based on a totem pole BLB (TPBLB) configuration, which allows the current to flow from high side to low side and vice versa during resonance. Hence, no auxiliary active switch is needed to provide soft switching for all semiconductor devices. The soft switching also reduces the body diode reverse recovery problem, hence allowing the TPBLB to operate in continuous conduction mode. Standard components are used to prove that the proposed converter is working with an acceptable performance compared with other BLB converters with soft switching. In order to achieve smooth input current waveform, high PF, and wide soft switching operations, a pulsewidth modulation controller is proposed and developed, which combines a conventional PF correction average current mode controller with several logic gates and a phase detector. A detailed analysis of the converter operation and control is presented. Design considerations and parameter values calculations are given. An experimental prototype is developed and tested to verify the converter performance.", "author_names": [ "Khairul Safuan Muhammad", "Dylan Dah-Chuan Lu" ], "corpus_id": 21144030, "doc_id": "21144030", "n_citations": 46, "n_key_citations": 1, "score": 1, "title": "ZCS Bridgeless Boost PFC Rectifier Using Only Two Active Switches", "venue": "IEEE Transactions on Industrial Electronics", "year": 2015 }, { "abstract": "In this paper, a new single phase single stage ZCS PFC boost rectifier with reduced switch count is introduced. The efficiency of the proposed converter is improved by eliminating input stage diode bridge. Moreover, only two active switches are used to permit bi directional current flow from high voltage rail to low voltage rail and vice versa. Hence, no auxiliary switch is needed. A resonant inductor and a capacitor are used to make both switches operate at ZCS turn off and soft turn on. The proposed converter is developed by using totem pole bridgeless boost (TPBLB) converter. Standard components are used to prove that the proposed converter is working with acceptable performance compared to other bridgeless boost converters with soft switching. In addition, a PWM controller is proposed, which combines a conventional average current mode power factor correction (PFC) controller, several logic gates and a phase detector. A detailed analysis of the converter operation and control is supported by simulation results. Finally, a 400 W, 50 kHz experimental prototype is built to verify the theoretical analysis and performance of the proposed converter.", "author_names": [ "Khairul Safuan Muhammad", "Dylan Dah-Chuan Lu" ], "corpus_id": 33828944, "doc_id": "33828944", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Single phase single stage ZCS boost PFC rectifier with reduced switch count", "venue": "2014 Australasian Universities Power Engineering Conference (AUPEC)", "year": 2014 }, { "abstract": "A new bridgeless single phase ac dc converter with a natural power factor correction (PFC) is proposed. Compared with existing single phase bridgeless topologies, the proposed topology has the merits of less component counts. The absence of an input diode bridge and less conduction losses; hence, improved thermal management compared to existing PFC rectifiers is obtained. The proposed topology is designed to work in resonant mode to achieve an automatic PFC close to unity in a simple and effective manner. The resonant mode operation gives additional advantages such as zero current turn on in the active power switches. Keywords Bridgeless AC DC Converters, Power factor correction, Resonant power conversion Zero Current Switching, Total harmonic distortion Pseudo boost converters, Voltage gain INTRODUCTION Power factor correction (PFC) techniques are becoming necessary for many types of electronic equipment especially in the telecommunication and computer industries to meet harmonic regulations. Also, higher power density and lower system cost are always very desirable features, especially for low power supplies. Most of the PFC rectifiers utilize a boost or buck boost topology converter at their front end due to its high power factor (PF) capability. However, a conventional PFC scheme has lower efficiency due to significant losses in the diode bridge. During each switching cycle interval, the current flows through three power semiconductor devices. The forward voltage drop across the bridge diodes degrades the converter efficiency, especially at low line input voltage [1].Pseudo boost converters are thus named because the voltage transfer ratio of pseudo boost converter is similar to that of conventional boost converter, with no relation to the resonant parameters and switching frequency. A bridgeless PFC circuit allows the current to flow through a minimum number of switching devices compared to the conventional PFC circuit. Accordingly, the converters conduction losses can be significantly reduced, and higher efficiency and lower cost can be obtained. However, most of the previous proposed bridgeless PFC converters have at least one of the following drawbacks: 1) high components count, 2) Components are not fully utilized over whole ac line cycle, 3) complex control, 4) dc output voltage is always higher than the peak input voltage, 5) lack of galvanic isolation, and 6) due to the floating ground, some topologies require additional diodes and/or capacitors to minimize EMI. In order to overcome most of these problems, an interesting topology has been introduced with reduced component count. However, the proposed topology in still suffers from having at least two semiconductors in the current conduction path during each switching cycle. In [4] a zero current switch topology is presented. This topology has reduced component count; however, the load is floating with respect to the input. A novel low count topology has been introduced in [5] The proposed topology has low component count with an input stage similar to a boost converter. Here a new bridgeless PFC circuit based on the modified boost converter is introduced and presented Compared with existing single phase bridgeless topologies. The proposed topology has low component count, a single control signal, and non isolating output. Since the topology operates in discontinuous conduction mode, the proposed converter is intended for low power applications. The converter components are fully utilized during the positive and negative ac line cycle [9] Pseudo naming comes because this converters have voltage transformation ratio same as that of conventional boost converter, but it is independent of resonant parameters and duty ratio. Voltage conversion ratio can be further increased by quasi resonant technique [10] BRIDGELESS RESONANT PSEUDO BOOST PFC RECTIFIER Introduction The Bridgeless Resonant Pseudo boost PFC Converter circuitry consists of two MOSFET switches, two power diodes, resonant inductor and capacitor. At input side, LC filter is provided. The Bridgeless Resonant Pseudo boost PFC Rectifiers are designed to operate in discontinuous conduction mode (DCM) during the switch turn on interval and in resonant mode during the switch turn off intervals. As a result, the switch current stress is similar to the conventional DCM PFC converter, while the switch voltage stress is higher [1] Moreover, the two power switches Q1 and Q2 can be driven by the same control signal, which significantly simplifies the control circuitry. Basic circuit of Bridgeless Resonant Pseudo boost PFC Rectifier is shown in Fig 3.1. Referring to Figure 2.1, the switching conduction sequences are as follows: International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 98 www.ijergs.org Figure 2.1: The Bridgeless Resonant Pseudo boost PFC Rectifier During positive ac line cycle, Q1, DQ2, D2, D1 ,X (all switches are off) and 2) during negative ac line cycle, Q2,DQ1,D1,D2,X. On the other hand, the switching conduction sequences for the converter are as follows: 1) during positive ac line cycle, Q1, DQ2 D1, D2, X and 2) during negative ac line cycle, Q2, DQ1, D2, D1,X. Thus, during each switching period TS, the current path goes through only two or one semiconductor devices instead of three. As a result, the total conduction losses of the semiconductor devices will be considerably lower compared to the conventional bridgeless PFC converters. In addition, the following assumptions are made: input voltage is pure sinusoidal, ideal lossless components, the switching frequency (fs) is much higher than the ac line frequency (fL) and the output capacitor C0 is large enough such that the output voltage can be considered constant over the whole line period. Based on these assumptions, the circuit operations in one switching period Ts in a positive ac line cycle can be divided into four distinct topological stages. From simulation results, for an input voltage 110 V, fs (switching frequency) 50 kHz, simulation is performed in MATLAB Ra2010. The parameters used includes Lf 1mH and Cf 1 mF, L1 100 mH, C1 65nF and RL 500. Output voltage is obtained as 242V and output current as 0.4A. Output voltage step up. Switching frequency used is 50 kHz. Power factor is obtained near unity, 0.92 and Total Harmonic Distortion is only 2%.Output power is nearer to 100 W, so it is used only for low power application. Working Principle Resonant Pseudo boost PFC Rectifiers are designed to operate in discontinuousconduction mode (DCM) during the switch turnon interval and in resonant mode during the switch turn off intervals. As a result, the switch current stress is similar to the conventional DCM PFC converter, while the switch voltage stress is higher. Moreover, the two power switches Q1 and Q2 can be driven by the same control signal, which significantly simplifies the control circuitry. However, an isolated gate drive is required for the power switch Q1. Table I: Tabulation of simulated results Input Voltage 110 V Input Current 1.5 A Input Power Factor 0.92 THD 2% Output Voltage 242 V Output Current 0.4 A ZCS BRIDGELESS BOOST PFC RECTIFIER For further improving voltage conversion ratio of conventional boost converters a new converter can be designed. An alternative approach to soft switching in modified boost converters is to use quasi resonant (QR) techniques that can be cheaply implemented by using only a few passive components. This converter can operate with soft switching and PFC in low line applications. It is International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 99 www.ijergs.org economical because it requires only two active switches and two diodes for the main power circuit and a few passive components for soft switching. ZCS bridgelss boost PFC rectifiers are shown in fig 3.1. Figure 3.1: ZCS Bridgeless boost PFC Rectifier Operational modes: Stage 1: This stage starts when the switch Q1 is turned on. The body Diode of Q2 is forward biased by the inductor current IL1. Diodes are reverse biased by the voltage across C In this stage, the current through inductor L1 increases linearly with the input voltage, while the voltage across capacitor C1 remains constant at voltage VX. Figure 2.1: Mode 1 of ZCS Bridgeless boost PFC Rectifier International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 100 www.ijergs.org Stage 2: This stage starts when switch Q1 is turned OFF and diode D1 is turned ON simultaneously providing a path for the inductor currents IL1 .As a result, diode D2 remains reverse biased during this interval. The series tank consisting of L1 and C1 are excited by the input voltage VAC. The stage ends when the resonant current IL1 reaches zero. During this stage, capacitor C is charged until it reaches a peak value as shown in Figure 2.2 Figure 2.2: Mode 2 of ZCS Bridgeless boost PFC Rectifier Stage 3: During this stage diode D1 is forward biased to provide a path during the negative cycle of the resonating inductor current IL1. This stage ends when the inductor current reaches zero. Thus, during this stage diode D2 is switched ON under zero current conditions. Assuming the constant input voltage over a switching period, the capacitor is discharged until it reaches a voltage VX. Figure 2.3: Mode 3 of ZCS Bridgeless boost PFC Rectifier Stage 4: During this stage all switches are in their off state. The inductor current is zero, while the capacitor voltage remains constant (VX) It shall be noted that for this converter to operate as specified, the length of this stage must be greater than or equal to zero. International Journal of Engineering Research and General Science Volume 3, Issue 4, Part 2, July August, 2015 ISSN 2091 2730 101 www.ijergs.org Figure 2.4: Mode 4 of ZCS Bri", "author_names": [ "Anna Joy", "Neena Joseph Mani", "Acy M Kottalil" ], "corpus_id": 15415843, "doc_id": "15415843", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ZCS BRIDGELESS BOOST PFC RECTIFIER", "venue": "", "year": 2015 }, { "abstract": "This Paper presents a two stage LED driver topology fed via a single phase Vienna Rectifier which is modified form of a single leg of three phase Vienna Rectifier. Use of Vienna Rectifier in place of conventional bridge rectifier not only improves power quality with high input power factor, lower Total Harmonics Distortion (THD) half the number of switch requirement, higher efficiency with reduced voltage stress on active switches and probable standards within IEC61000 3 2 for class C load. LED works on constant current or constant voltage mode which is driven by a driver circuit (AC DC system) .Effective LED driver topologies comes in two or three stage configuration to improve the power quality and efficiency, here second stage is driven by a Boost converter controlled by Average Current mode controller to obtained the desired Phase Margin and Gain Margin for stability. The modeling, control and simulation of the driver circuit is presented for LED load.", "author_names": [ "Vinod Kumar Yadav", "Arun Kumar Verma", "Udaykumar R Yaragatti" ], "corpus_id": 219591152, "doc_id": "219591152", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Modelling and Control of Two Stage High PFC LED Driver Circuit using Average Current Control Method Driven by Vienna Rectifier", "venue": "2020 IEEE 9th Power India International Conference (PIICON)", "year": 2020 }, { "abstract": "The utilization of wide band gap devices has enabled high frequency operation of totem pole bridgeless PFC rectifier. However, most of the designs reported in the literature with frequency higher than 100 kHz operate under discontinuous conduction mode or critical mode to reduce the switching loss. This paper proposes a zero voltage transition (ZVT) technique for totem pole PFC rectifier under continuous conduction mode operation which enables efficient operation at switching frequencies well above 100 kHz. A simple auxiliary circuit consisting of a small auxiliary inductor and two active switches is placed in parallel with the main input filter inductor to achieve zero voltage switching of the main switches. The auxiliary switches operate with zero current switching (ZCS) and conduct current as short resonant pulses only during the critical turn on transition which results in very low losses in the auxiliary circuit. The timing of the auxiliary switches is adaptively controlled with respect to the grid voltage angle for optimized overall efficiency. The effectiveness of the proposed ZVT scheme has been validated through experiments based on a 2.4 kW 400 kHz hardware prototype with 98.35% peak efficiency.", "author_names": [ "Ziwei Yu", "Yinglai Xia", "Raja Ayyanar" ], "corpus_id": 115376654, "doc_id": "115376654", "n_citations": 7, "n_key_citations": 1, "score": 0, "title": "A Simple ZVT Auxiliary Circuit for Totem Pole Bridgeless PFC Rectifier", "venue": "IEEE Transactions on Industry Applications", "year": 2019 }, { "abstract": "A bridgeless AC/DC converter for the power factor correction application is proposed in this paper. The diode bridge rectifier is removed in this converter by providing two separate paths of current for each half cycle of the AC voltage source; conduction losses are alleviated by decreasing the total number of switches in the conduction path of the current. In the proposed converter of this paper, switching losses are reduced by providing zero voltage switching (ZVS) condition for power MOSFETs using an auxiliary active clamp branch. By utilizing a series resonant circuit, zero current switching (ZCS) turn off is achieved for output diodes, and the reverse recovery losses are eliminated.", "author_names": [ "A Valizadeh", "Ali Yazdian Varjani" ], "corpus_id": 233332516, "doc_id": "233332516", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "A Bridgeless Soft Switching PFC AC/DC Converter With Active Clamping Auxiliary Circuit", "venue": "2021 12th Power Electronics, Drive Systems, and Technologies Conference (PEDSTC)", "year": 2021 }, { "abstract": "This paper presents a new four quadrant bridgeless boost type rectifier with the use of Active Virtual Ground (AVG) technology. The presented topology can step up the AC grid voltage to a regulated DC voltage under a stable bidirectional current flow with real power or reactive power delivery. By using bridgeless rectifier configuration and 3 level switching method, only two high frequency switches are required through the four quadrant operation. Small input current ripple is guaranteed by the AVG circuit. A high efficiency system is also able to be guaranteed by low semiconductor loss. Benefit from the AVG technology, a LCL filter is formed at the input during the operation. The filter capacitor clamps the voltage ripple between the grid and the DC bus terminal. Hence the leakage current in the bridgeless PFC is minimized and causes a low common mode (CM) noise system. The differential mode (DM) noise is also maintained in a small value due to the small grid current ripple. Finally a high efficiency and low noise four quadrant rectifier is built. The presented topology is successfully implemented on a 750W prototype and the performance is experimentally verified which show a good agreement with the theoretical knowledge. The operation principles and the controller implementation are also described in details.", "author_names": [ "Ken King Man Siu", "Carl Ngai Man Ho", "Dong Li", "River Tin-Ho Li" ], "corpus_id": 21758807, "doc_id": "21758807", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "A four quadrant active virtual ground rectifier by using two high frequency switches", "venue": "IECON 2017 43rd Annual Conference of the IEEE Industrial Electronics Society", "year": 2017 }, { "abstract": "A novel bridgeless interleaved boost PFC rectifier is proposed for improving power efficiency and system performance in this paper. By combining the conventional bridgeless topology and the interleaved technology, this rectifier is comprised of two interleaved boost branches without the front end diode bridge. Each branch operates in every half line cycle, together with the current following through a minimum number of switching devices. By using the interleaved approach, this topology not only decreases the current stress of the switching devices but also reduces the current and voltage ripple. Moreover, as operating in critical conduction mode (CrM) all the switches can achieve soft switching characteristics to reduce the switching loss and evidently raise the conversion efficiency. Using a conventional interleaved controller, simple control scheme can be employed to the proposed converter. The operational principle and theoretical analysis of the proposed converter are presented. Finally, simulations based on actual semi conductor models were carried out to verify the feasibility and exactness of the proposed rectifier.", "author_names": [ "Guoen Cao", "Hee-Jun Kim" ], "corpus_id": 38685782, "doc_id": "38685782", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "A novel critical conduction mode bridgeless interleaved boost PFC rectifier", "venue": "2014 International Power Electronics Conference (IPEC Hiroshima 2014 ECCE ASIA)", "year": 2014 }, { "abstract": "An improved bridgeless interleaved boost PFC rectifier is proposed to improve power efficiency and component utilization in this paper. By combining the conventional bridge less PFC circuit and the interleaved technology, the proposed rectifier is comprised of two interleaved boost branches without the front end diode bridge. Auxiliary diodes are employed to eliminate undesired circulating loop. The magnetic component utilization is improved by symmetrically coupling two inductors on unique core. According to the interleaved approach, each switch can operate in the whole line cycle. Moreover, this circuit not only decreases the current stress of the switching devices but also reduces the current and voltage ripple. As operating in critical conduction mode (CrM) all the switches can achieve soft switching characteristics to reduce the switching loss and evidently raise the conversion efficiency. Using a conventional interleaved controller, simple control scheme can be employed to the proposed converter. The operational principle and theoretical analysis of the proposed converter are presented. Finally, an 600 W experimental prototype was built to verify the theoretical analysis and feasibility of the proposed converter. The system efficiency was achieved up to 97.3% with very low current THD.", "author_names": [ "Guoen Cao", "Hee-Jun Kim" ], "corpus_id": 23534100, "doc_id": "23534100", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "An improved bridgeless interleaved boost PFC rectifier with optimized magnetic utilization and reduced sensing noise", "venue": "2014 IEEE International Conference on Industrial Technology (ICIT)", "year": 2014 }, { "abstract": "The power conversion circuit of a three phase Vienna or Modular Boost switching power factor corrected (PFC) rectifier uses three controlled switches, eighteen diodes and two output split capacitors. Three PFC controller circuits are necessary for conversion circuit's voltage regulation, power factor control and input current waveform improvement. The circuit has been modified to have fewer active and passive components in the power circuit. The input voltages and currents are sensed and conditioned to one voltage and one current signal for the feedback controller circuit. Reduction of controlled switches, diodes of the power circuit, sensors, isolation, base drive supply circuits makes overall operation of the circuit reliable. The proposed three phase boost PFC rectifier circuit is easy to design, fabricate, operate and maintain. It occupies less space and is lighter in weight. Disadvantages of unidirectional power flow and only step up voltage gain characteristics of conventional three phase Vienna/Modular Boost rectifiers remain in the proposed modified circuits.", "author_names": [ "M Nasir Uddin", "Amina Hasan Abedin", "Khandaker Lubaba Bashar", "Samia Islam", "M A Choudhury" ], "corpus_id": 31620503, "doc_id": "31620503", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Three phase one switch modular boost/vienna power factor corrected (PFC) rectifier", "venue": "2017 IEEE International Conference on Industrial Technology (ICIT)", "year": 2017 } ]

[ { "abstract": "Deploying earth abundant copper as a redox mediator in dye sensitized solar cells (DSCs) has been found to be a very promising strategy to achieve higher photovoltage and power conversion efficiencies in full sun (100 mW cm 2) and in low/diffuse light conditions. Achieving higher photovoltage without compromising photocurrent helped copper electrolyte attract considerable attention among alternate electrolytes currently employed in DSCs. The very small reorganization energy between Cu(I) and Cu(II) and small molecular size helped copper achieve unit regeneration efficiency, with a driving force as low as 100 mV and a high diffusion coefficient (Dn) leading to better diffusion length (Ln) and charge collection efficiency (ecc) Mass transport issues were also found to be improved for copper electrolytes in comparison with cobalt electrolytes. As it is inert to silver and other electrical contacts used in DSCs and possesses higher mobility even in solid state, copper based electrolyte is a promising candidate to spearhead the commercialization of dye solar technology. In this regard, a detailed evaluation of internal electron transfer dynamics is highly essential to understand the limiting processes in these devices. In the present study, we performed a comparison between copper, cobalt and iodine electrolytes using the same dye (LEG4) semiconductor (TiO2) and additive concentrations to understand in detail the charge transfer processes leading to higher photoconversion efficiencies and also probe the various deleterious processes taking place in copper devices that provide opportunities to further improve its performance in future.", "author_names": [ "Sourav Pradhan", "Anders Hagfeldt", "Suraj Soman" ], "corpus_id": 104749462, "doc_id": "104749462", "n_citations": 33, "n_key_citations": 1, "score": 1, "title": "Resurgence of DSCs with copper electrolyte: a detailed investigation of interfacial charge dynamics with cobalt and iodine based electrolytes", "venue": "", "year": 2018 }, { "abstract": "Iodine binding to thiophene rings in dyes for dye sensitized solar cells (DSCs) has been hypothesized to be performance degrading in a number of literature cases. Binding of iodine to dyes near the semiconductor surface can promote undesirable electron transfers and lower the overall efficiency of devices. Six thiophene or furan containing dye analogs were synthesized to analyze iodine binding to the dyes via Raman spectroscopy, UV Vis studies, device performance metrics and density functional theory (DFT) based computations. Evidence suggests I2 binds thiophene based dyes stronger than furan based dyes. This leads to higher DSC device currents and voltages from furan analogues, and longer electron lifetimes in DSC devices using furan based dyes. Raman spectrum of the TiO2 surface bound dyes reveals additional and more instense peaks for thiophene dyes in the presence of I2 relative to no I2. Additionally, broader and shifted UV Vis peaks are observed for thiophene dyes in the presence of I2 on TiO2 films suggesting significant interaction between the dye molecules and I2. These observations are also supported by DFT and TD DFT calculations which indicate the absence of a key geometric energy minimum in the dye I2 ground state for furan dyes which are readily observed for the thiophene based analogues.", "author_names": [ "Alexandra Baumann", "Hammad Cheema", "Md Abdus Sabuj", "Louis E McNamara", "Yanbing Zhang", "Adithya Peddapuram", "Suong T T Nguyen", "Davita L Watkins", "Nathan I Hammer", "Neeraj Rai", "Jared H Delcamp" ], "corpus_id": 49314009, "doc_id": "49314009", "n_citations": 14, "n_key_citations": 0, "score": 0, "title": "Iodine binding with thiophene and furan based dyes for DSCs.", "venue": "Physical chemistry chemical physics PCCP", "year": 2018 }, { "abstract": "Thieno[3,4 b]pyrazine (TPz) is examined as an electron deficient p bridge enabling near infrared (NIR) spectral access in dye sensitized solar cells (DSCs) Seven dissymmetric dyes for DSCs were synthesized (NL2 NL8) with TPz as the p bridge utilizing palladium catalyzed C H activation methodology. C H bond cross coupling was uniquely effective among the cross couplings and electrophilic aromatic substitution reactions analyzed in monofunctionalizing the TPz building block. The TPz based NL2 NL8 dyes examine the effects of various donors, p spacers, and acceptors within the donor p bridge acceptor (D p A) dye design. Proaromatic TPz stabilizes the excited state oxidation potential (E(s+/s* of the dyes by maintaining aromaticity upon excitation of the dye molecule. This leads to concise conjugated systems capable of accessing the NIR region. Through judicious structural modifications, dye band gaps were reduced to 1.48 eV, and power conversion efficiencies (PCEs) reached 7.1% in this first generation TPz dye series.", "author_names": [ "Nalaka P Liyanage", "Aswani Yella", "Mohammad Khaja Nazeeruddin", "Michael Gratzel", "Jared H Delcamp" ], "corpus_id": 206414205, "doc_id": "206414205", "n_citations": 43, "n_key_citations": 0, "score": 0, "title": "Thieno[3,4 b]pyrazine as an Electron Deficient p Bridge in D A p A DSCs.", "venue": "ACS applied materials interfaces", "year": 2016 }, { "abstract": "Sequential series multijunction dye sensitized solar cells (SSM DSCs) which are mechanically stacked single illuminated area DSC devices wired in series, are reported to have exceptionally high photovoltages (Voc) ranging from 1.9 4.7 V from 2 5 stacked subcells. The use of multiple photoactive films under one area within the SSM DSC framework is made possible by fine tuning the thickness of TiO2 in each device and by judicious dye selection to allow for excellent light distribution among the films, termed as \"photon management\" The SSM DSC approach allows for incorporation of materials designed to use the maximal potential energy of photons in each region of the solar spectrum. Importantly, SSM DSCs were observed to maintain high Voc under low light conditions, rendering these systems very attractive for indoor applications. Additionally, an SSM DSC was found to have a solar to fuel conversion efficiency of 2% (2.7% including H2 production) for the reduction of CO2 to CO with IrO2 and Au2O3 electrocatalysts, without an external bias.", "author_names": [ "Hammad Cheema", "Roberta R Rodrigues", "Jared H Delcamp" ], "corpus_id": 104125999, "doc_id": "104125999", "n_citations": 12, "n_key_citations": 0, "score": 0, "title": "Sequential series multijunction dye sensitized solar cells (SSM DSCs) 4.7 volts from a single illuminated area", "venue": "", "year": 2017 }, { "abstract": "A modular approach based on Suzuki Miyaura cross coupling and Miyaura borylation has been used to prepare two cyclometallated [Ru(N^N)2(C^N) complexes which possess either a carboxylic or phosphonic acid group attached via a phenylene spacer to the 4 position of the pyridine ring in the C^N ligand. The key intermediate in the synthetic pathway is [Ru(bpy)2(1) where bpy 2,2' bipyridine and H1 is 4 chloro 2 phenylpyridine. The crystal structure of [Ru(bpy)2(1)[PF6] is presented. Reaction of [Ru(bpy)2(1)[PF6] with 4 carboxyphenylboronic acid leads to [Ru(bpy)2(H6)[PF6] while the phosphonic acid analogue is isolated as the zwitterion [Ru(bpy)2(H5) The cyclometallated complexes have been characterized by mass spectrometry, multinuclear NMR spectroscopy, absorption spectroscopy and electrochemistry. [Ru(bpy)2(5) adsorbs onto NiO FTO/NiO electrodes (confirmed by solid state absorption spectroscopy) and its performance in p type dye sensitized solar cells (DSCs) has been compared to that of the standard dye P1; two screen printed layers of NiO give better DSC performances than one layer. Duplicate DSCs containing [Ru(bpy)2(H5) achieve short circuit current densities (JSC) of 3.38 and 3.34 mA cm 2 and photoconversion efficiencies (e) of 0.116 and 0.109% respectively, compared to values of JSC 1.84 and 1.96 mA cm 2 and e 0.057 and 0.051% for P1. Despite its simple dye structure, the performance of [Ru(bpy)2(H5) parallels the best performing cyclometallated ruthenium(II) dye in p type DSCs reported previously (He et al. J. Phys. Chem. C, 2014, 118, 16518) and confirms the effectiveness of a phosphonic acid anchor in the dye and the attachment of the anchoring unit to the pyridine (rather than phenyl) ring of the cyclometallating ligand.", "author_names": [ "Fabian Brunner", "Nathalie Marinakis", "Cederic Wobill", "Markus Willgert", "Cathrin D Ertl", "Tatjana Kosmalski", "Markus Neuburger", "Biljana Bozic-Weber", "Thilo Glatzel", "Edwin C Constable", "Catherine E Housecroft" ], "corpus_id": 100053185, "doc_id": "100053185", "n_citations": 13, "n_key_citations": 1, "score": 0, "title": "Modular synthesis of simple cycloruthenated complexes with state of the art performance in p type DSCs", "venue": "", "year": 2016 }, { "abstract": "Abstract For the first time laser assisted sealing using lead free glass frit was successfully applied for producing a DSC panel with a total sealed area of 1638 cm2 and active area of 990 cm2. The panel comprises 90 DSCs individual glass sealed cells (140 mm x 13 mm) arranged in 10 sub modules (150 mm x 150 mm) Indoor aging of individual sub modules in dark and at ambient temperature for 100 days showed rather small decrease of the photocurrent conversion efficiency: 1.23 10 4 day 1. The DSC panel was tested under outdoor working conditions during 47 days in summer time (Porto, Portugal) where the average day illumination level was about 6 kW h m 2. After 47 days of continuous power production the assembled panel kept 86% of the initial efficiency. No leakage of electrolyte or visual defects in the sealed glass frit were detected. Glass sealed DSCs performed superior stability under 1000 h of ageing in a climatic chamber when compared to polymer sealed cells. The results show that the laser assisted sealing can be applied to large area DSC modules.", "author_names": [ "Dzmitry Ivanou", "R Santos", "Jose Macaira", "Luisa Andrade", "Adelio Mendes" ], "corpus_id": 124217046, "doc_id": "124217046", "n_citations": 15, "n_key_citations": 1, "score": 0, "title": "Laser assisted glass frit sealing for production large area DSCs panels", "venue": "", "year": 2016 }, { "abstract": "Abstract Chemistry is facing the challenge of delivering new materials for energy harvesting and management. The development of a materials chemistry in which scarce elements are replaced by more abundant and sustainable materials is crucial to the commercial and societal acceptance of these new technologies. This review surveys the use of complexes of Earth abundant metals from the first row of the d block as photosensitizers in dye sensitized solar cells (DSCs) an emerging technology for solar light harvesting in which state of the art devices currently use ruthenium or other platinum group metal complexes as photosensitizers.", "author_names": [ "Biljana Bozic-Weber", "Edwin C Constable", "Catherine E Housecroft" ], "corpus_id": 95646819, "doc_id": "95646819", "n_citations": 125, "n_key_citations": 0, "score": 0, "title": "Light harvesting with Earth abundant d block metals: Development of sensitizers in dye sensitized solar cells (DSCs)", "venue": "", "year": 2013 }, { "abstract": "Dental stem cells (DSCs) are a promising source of mesenchymal stem cells for use in cell therapy and regenerative medicine. To date, seven types of DSCs have been described in the literature: Dental Pulp Stem Cells (DPSCs) Stem cells from Human Exfoliated Deciduous teeth (SHED) Periodontal Ligament Stem Cells (PDLSCs) Dental Follicle Progenitor Cells (DFPCs) Stem Cells from Apical Papilla (SCAP) Gingival Mesenchymal Stem Cells (GMSCs) and human Natal Dental Pulp Stem Cells (NDP SCs) All these easily accessible stem cells can be derived from dental tissues obtained from young or adult patients.", "author_names": [ "Chiara Gardin", "Sara Ricci", "Letizia Ferroni" ], "corpus_id": 89470336, "doc_id": "89470336", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "Dental Stem Cells (DSCs) Classification and Properties", "venue": "", "year": 2016 }, { "abstract": "The adsorption behavior of two symmetrical indolenine based squaraines, indicated with VG1 C2 and VG1 C10, sensitizing electrodeposited mesoporous zinc oxide (ZnO) was studied and compared with that of di tetrabutylammonium cis bis(isothiocyanato) bis(2,2' bipyridyl 4,4' dicarboxylato) ruthenium (II) (N719) The choice of squaraines as metal free dye sensitizers was motivated by their far red NIR sensitivity with respect to the traditional Ru complex based dyes, the ease of their preparation and their higher molar extinction coefficient. The electrochemically grown ZnO here described were porous due to the high volume yield of electrodeposition (about 104 cm3 of ZnO per unit charge of electrolysis) In the present analysis the process of sensitization of TiO2 with the same set of dyes and the performance of the corresponding DSCs were also considered for sake of comparison. VG1 C2 sensitizer proved to be particularly effective electron injector in ZnO electrodes giving larger photocurrents in VG1 C2 sensitized ZnO with respect to TiO2. The latter system presented higher kinetic stability of the photoinjected charges as evidenced by the larger photovoltages of TiO2 based DSCs with respect to ZnO based devices with the same sensitizer. The long alkyl substituents in squaraine VG1 C10 inhibit electron injection in ZnO and a specific effect of electrical passivation of the ZnO surface introduced by the bulky apolar groups was claimed. Overall efficiencies in the order of 1% were measured with the ZnO based DSCs under AM 1.5 solar simulator when the photoactive area and the thickness of ZnO films were 0.5 cm2 and 2 mm, respectively. These results on ZnO based DSCs with the oxide prepared at temperatures below 260 degC are particularly interesting considering the relatively large area and small thickness of the related electrodes, which makes them in principle useful for application in weakly absorbing devices utilizing flexible substrates.", "author_names": [ "Iole Venditti", "Nadia Barbero", "Maria Vittoria Russo", "Aldo Di Carlo", "Franco Decker", "Ilaria Fratoddi", "Claudia Barolo", "Danilo Dini" ], "corpus_id": 98555847, "doc_id": "98555847", "n_citations": 36, "n_key_citations": 0, "score": 0, "title": "Electrodeposited ZnO with squaraine sentisizers as photoactive anode of DSCs", "venue": "", "year": 2014 }, { "abstract": "Undyed mesoporous NiO in the configuration of thin film (thickness 2 3 mm) presents photoelectrochemical activity as cathode of a p type dye sensitized solar cell (p DSC) towards the reduction of triiodide to iodide under irradiation with a solar simulator. The photoelectroactivity of the oxide prepared via microwave plasma sintering (or rapid discharge sintering, RDS) has been observed in the spectral range 300 500 nm with the incident photon to current conversion efficiency (IPCE) reaching a maximum of 8.7 at 375 nm. Upon sensitization, the characteristic photoelectrochemical activity of NiO can be either enhanced or depressed depending on the nature of the dye sensitizer. The comparative analysis of the JV and IPCE curves of the p DSCs based on bare NiO and four differently sensitized NiO cathodes reveals that N719, black dye (BD) and commercial squaraine 2 (SQ2) decrease the efficiency of conversion of dyed NiO with respect to bare NiO in the range of photoelectroactivity of the latter (300 500 nm) The fourth dye P1 represents the sole exception since its employment brings about an enhancement of the quantum efficiency of P1 sensitized vs. unsensitized NiO up to a maximum of 21 within the spectral interval of reference for NiO (300 500 nm) Outside the range of NiO photoelectrochemical activity, i.e. l 500 nm, only N719 does not introduce a gain of quantum efficiency with respect to bare NiO despite the observation of spectral sensitization up to 580 nm for N719 sensitized NiO. The impedance spectra recorded under illumination shows a direct proportionality between the overall efficiency (e) of the variously sensitized p DSCs and the amplitude of the semicircle which is generally associated with the process of charge recombination at the electrode/electrolyte interface with e decreasing with the increase of the recombination resistance.", "author_names": [ "S Sheehan", "Gaia Clara Mercedes Naponiello", "Fabrice Odobel", "Denis P Dowling", "Aldo Di Carlo", "Danilo Dini" ], "corpus_id": 98676626, "doc_id": "98676626", "n_citations": 41, "n_key_citations": 3, "score": 0, "title": "Comparison of the photoelectrochemical properties of RDS NiO thin films for p type DSCs with different organic and organometallic dye sensitizers and evidence of a direct correlation between cell efficiency and charge recombination", "venue": "Journal of Solid State Electrochemistry", "year": 2014 } ]

[ { "abstract": "In this paper, we describe a solution for wafer edge and bevel apex defect inspection for a 300 mm semiconductor automated fab. Traditionally, we have used an advanced macro inspection solution for topside wafer inspection. The automated tool revealed that defects surfacing after the back end of line (BEOL) copper chemical mechanical polish planarization (Cu CMP) process were significantly impacting yields. We suspected that particles and film on the edge and bevel were flaking off on to the top of the wafers, causing the yield degradation. However, we needed more information from the edge to confirm our hypothesis. Since offline manual edge analysis was not cost effective for larger wafer sampling, we sought to develop an inline bevel inspection at the CMP sector that was fast, cost effective, and integrated with the advanced macro inspection tool. We also established a long term goal of expanding the process into an all surfaces inspection within one manufacturing operation step. This paper describes how we integrated the top down macro and edge bevel inspection into a single automated operation, enhancing data collection and our ability to take corrective action. The process includes full top and complete edge bevel inspection of less than 10 percent of each lot. Although we ran sample tests to inspect edges after numerous processes, this paper focuses on BEOL Cu CMP inspection, including data collection and corrective actions. We also highlight the benefits of edge inspection, and the new level of automated process control. As a result of edge inspection, we have taken corrective actions that have reduced defects on the edge bevel, and improved wafer final test yields by 10 percent from the baseline", "author_names": [ "Jesus Morillo", "Thomas Houghton", "J Bauer", "Rob Smith", "Richard F Shay" ], "corpus_id": 31212127, "doc_id": "31212127", "n_citations": 9, "n_key_citations": 0, "score": 1, "title": "Edge and bevel automated defect inspection for 300mm production wafers in manufacturing", "venue": "IEEE/SEMI Conference and Workshop on Advanced Semiconductor Manufacturing 2005.", "year": 2005 }, { "abstract": "As 3D TSV technology based solutions are moving into volume manufacturing, monitoring of the processed device wafer through temporary bonding, thinning, TSV reveal, metallization and de bonding processes remains a key yield concern. Edge chipping, micro cracks, device carrier misalignment, adhesive residue at edge and delamination during device wafer thinning and later process steps are some of the process challenges. Monitoring of device wafer edge for bond process defects and device carrier concentricity is critical to ramp up yields and reduce the overall cost of ownership of the TSV process flow. Additionally, to get the highest yield from temporary bonding process, thickness and TTV (total thickness variation) measurements from different layers of the bonded stack as well as detecting bonding voids in one single measurement run is vital. In this contribution, we will discuss the main factors affecting edge yield of temporary bonded and thinned device wafers and demonstrate the use of automated edge inspection and metrology for process control and yield improvement.", "author_names": [ "Jie Gong", "Sumant Sood", "Rohit Bhat", "Sina Jahanbin", "Prashant A Aji", "Thomas Uhrmann", "Julian Bravin", "Jurgen Burggraf", "Markus Wimplinger", "Paul Lindner" ], "corpus_id": 23809513, "doc_id": "23809513", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Wafer edge defect study of temporary bonded and thin wafers in TSV process flow", "venue": "2015 IEEE 65th Electronic Components and Technology Conference (ECTC)", "year": 2015 }, { "abstract": "As device sizes continue to increase on devices at 2x nm design rule and beyond and high wafer stress is worsening due to multi film stacking in the vertical memory process, we observe an increasing trend in edge yield issues worldwide. Wafer edge inspection and metrology become thus critical to drive root cause analysis for improving the yield during a new technology ramp. Nowadays, wafer defectivity correlation to edge is also key for production monitoring, but not without challenges due to the diverse sensitivity demands for the wafer front side, as compared to the wafer edge and back side. In this paper we are able to demonstrate that a cluster inspection platform with the proper balance of sensitivity and throughput is a key enabler for production monitoring. The study required high resolution imaging of the wafer front side, accurate metrology and defect binning capability at the wafer edge, and unique capability to isolate issues that matter in the wafer backside all in a single inspection cluster tool platform. This setup allows for faster time to decisions and eliminates the need to rely on other sources of inspection data. We present several examples of defectivity correlation between the wafer edge and both front and back side, with scanning electron microscope (SEM) examples showing same defect types captured. The root cause for edge defectivity is very often found to be in the crossover of edge bead removal (EBR) lines from successive steps. High quality and accurate EBR metrology is thus essential on many process steps including on backend layers where many EBR lines are found and need to be distinguished. Likewise, anomalies in metrology data of the edge profile can also act as an important indicator of possible defectivity on the wafer. Keywords Wafer Edge, Inspection, Metrology, Defect correlation, Root cause analysis", "author_names": [ "Tae-Heon Kim", "Jaehyoung Oh" ], "corpus_id": 186202217, "doc_id": "186202217", "n_citations": 3, "n_key_citations": 0, "score": 0, "title": "Criticality of Wafer Edge Inspection and Metrology Data to All Surface Defectivity Root Cause and Yield Analysis", "venue": "", "year": 2016 }, { "abstract": "Monitoring detectivity of the wafer edge, bevel and apex the areas beyond the pattern is becoming increasingly important in the yield enhancement efforts of high end fabs. In this paper we present a methodology for root cause analysis of edge and bevel defects, based on inline SEM review and EDX based material analysis.", "author_names": [ "Ronnie Porat", "Kfir Dotan", "Shirley Hemar", "Lior Levin", "K Li", "G Sung" ], "corpus_id": 38941712, "doc_id": "38941712", "n_citations": 6, "n_key_citations": 1, "score": 0, "title": "SEM based methodology for root cause analysis of wafer edge and bevel defects", "venue": "2008 IEEE/SEMI Advanced Semiconductor Manufacturing Conference", "year": 2008 }, { "abstract": "3D integration requires innovative process control solutions to ensure the integrity of the device wafers that are bonded, thinned and then de bonded before permanent bonding. Right now, most 3D TSV pilot lines use a number of semi auto or manual inspection tools: Microscopes, interferometers, profilometers and acoustic microscopes. Other sites use automated scanning inspection tools that are not adapted to detect specific 3D integration defectivity. Leading the field, IMEC and Nanda Tech partnered to tailor the Spark platform to the requirements of 3D integration process control. From the pilot line to the high volume manufacturing fabs, Spark provides a flexible process control platform, adapted to handling bonded wafers and finding the defects of interest that will affect expensive customer wafers.", "author_names": [ "Pierre-Yves Guittet", "Lars Markwort", "Greg Savage", "Christoph Kappel", "Sandip Halder", "Alain Phommahaxay", "Anne Jourdain", "Andy Miller" ], "corpus_id": 28664849, "doc_id": "28664849", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "High speed full wafer monitoring of surface, edge and bonding interface for 3Dstacking", "venue": "2011 IEEE 13th Electronics Packaging Technology Conference", "year": 2011 }, { "abstract": "Introduction In today's business climate, continuous i n n ova t i o n a n d p ro d u c t i v i t y improvements are essential to the survival of any company. In the semiconductor industry, productivity improvement is generally accomplished using decreased cost per function, economy of scale, increased wafer diameter, process simplification and yield enhancement. The challenges for extreme edge dies increased with the conversion from 200mm to 300mm wafer processing, and will be further increased by the transition to 450mm [3] Increasingly sophisticated and more expensive equipment is required for technology shrinks, making the acquisition of funds for capacity expansion ever more difficult. Process simplification can only be done to a certain extent. Emphasis is therefore placed on fast yield learning, which claims the biggest financial leverage. Due to the narrower process windows at smaller technology nodes, centerto edge uniformity over the wafer is crucial for yield [4] Consequently, wafer edge and bevel induced yield loss were introduced as critical elements to the International Technology Roadmap for Semiconductors (ITRS) in 2005 and are still considered challenging [5, 6] The ITRS also highlights the importance of r im problems in the wafer edge exclusion guideline. A recent repor t descr ibed the economically optimized technology transfer and ramp methodology from development to a mass production site within a global fabrication cluster [7] This paper outlines the wafer edge yield engineering methodology, which was essential for the reported steep production ramp.", "author_names": [ "Oguz Yavas", "Ernst-christian Richter", "Christian Kluthe", "Markus Sickmoeller" ], "corpus_id": 13591736, "doc_id": "13591736", "n_citations": 4, "n_key_citations": 0, "score": 0, "title": "Wafer edge yield engineering in leading edge DRAM manufacturing", "venue": "", "year": 2009 }, { "abstract": "The defect density reduction is one of the main challenges to increase the yield. This article presents a mechanism of defect formation specific to the STI module. This defect flake like appears during HDP CVD process deposition. It comes from oxide bubbles localised at the bevel of the substrate. The suppression of this defect consists into the bevel shape optimization. Moreover, process improvement as resist strip post etch contributes to clean the bevel from polymer and reduces strongly the flakes density.", "author_names": [ "Virginie Dureuil", "Jean-Luc Baltzinger", "Kevin Tastets", "L Vallier", "N Wlodarczyk", "O Bernaud", "J Leroueille", "C Mouroux" ], "corpus_id": 19671542, "doc_id": "19671542", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Wafer bevel shape inducing high defect density in shallow trench isolation process", "venue": "2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2010 }, { "abstract": "This paper describes a methodology for defect review and process monitoring on wafer's upper bevel and apex. A case study gives an example of successful application.", "author_names": [ "Britta Becker", "Ronnie Porat", "Hanan Eschwege" ], "corpus_id": 28073147, "doc_id": "28073147", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Identification of yield loss sources in the outer dies using SEM based wafer bevel review", "venue": "2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference (ASMC)", "year": 2010 }, { "abstract": "Defects on the backside of wafers can be either tool or process induced and can cause lithography related issues such as focus deviation or chuck contamination. Tool induced scratches, process induced contamination, or residues on the back of wafers often have unique signatures, such as a repeatable scratch caused by wafer handling equipment or a chuck imprint on the backside of a wafer. Certain backside defect signatures such as large scratches or divots can contribute to wafer breakage or reliability issues. Spatial Pattern Recognition (SPR) is a method of comparing defect patterns at the wafer level with known defect signatures stored in a library that is created from process data. These defect signatures can represent systemic issues with process tools, handling equipment, or the process itself. This paper describes a backside inspection method for identifying wafers with both known and new spatial pattern signatures. By reporting the frequency of each signature category, process partitioning can efficiently trace the source of these problems. In addition, new defect signatures can be automatically learned and added to the library. The paper also includes examples of how this method was used to identify backside defect patterns caused by process and tool excursions in a 300mm fabricator.", "author_names": [ "Alan Carlson", "Prasad Bachiraju", "Jennifer Clark", "Dale Trost" ], "corpus_id": 122679357, "doc_id": "122679357", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Use of wafer backside inspection and SPR to address systemic tool and process issues", "venue": "Advanced Lithography", "year": 2010 }, { "abstract": "We regard the stringent adoption of factory automation as the right strategy to efficiently leverage a 200 mm fab's competitiveness. In this article we exemplarily show how the Dresden fab cut its own path in the face of the transition challenge from a high volume low mix fab to a high mix low volume fab. We discuss the advantages of our conveyor type transport system with respect to our automation strategy and its extendibility to direct tool loading. A comparison of our transport system with typical 300 mm performance data and current ITRS requirements [1] is presented. We describe the positive influence of the taken factory automation measures on typical key manufacturing indicators like cycle time, tool utilization, head count efficiency, variability improvement, cost efficiency and quality.", "author_names": [ "Harald Heinrich", "Germar Schneider", "Frank Heinlein", "Sophia Keil", "Arthur Deutschlander", "Rainer Lasch" ], "corpus_id": 22148769, "doc_id": "22148769", "n_citations": 13, "n_key_citations": 0, "score": 0, "title": "Pursuing the Increase of Factory Automation in 200mm Frontend Manufacturing to Manage the Changes Imposed by the Transitionfrom High Volume Low Mix to High Mix Low Volume Production", "venue": "2008 IEEE/SEMI Advanced Semiconductor Manufacturing Conference", "year": 2008 } ]

[ { "abstract": "A fundamental aim in the field of catalysis is the development of new modes of small molecule activation. One approach toward the catalytic activation of organic molecules that has received much attention recently is visible light photoredox catalysis. In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single electron transfer (SET) processes with organic substrates upon photoexcitation with visible light. Many of the most commonly employed visible light photocatalysts are polypyridyl complexes of ruthenium and iridium, and are typified by the complex tris(2,2' bipyridine) ruthenium(II) or Ru(bpy)32+ (Figure 1) These complexes absorb light in the visible region of the electromagnetic spectrum to give stable, long lived photoexcited states.1,2 The lifetime of the excited species is sufficiently long (1100 ns for Ru(bpy)32+ that it may engage in bimolecular electron transfer reactions in competition with deactivation pathways.3 Although these species are poor single electron oxidants and reductants in the ground state, excitation of an electron affords excited states that are very potent single electron transfer reagents. Importantly, the conversion of these bench stable, benign catalysts to redox active species upon irradiation with simple household lightbulbs represents a remarkably chemoselective trigger to induce unique and valuable catalytic processes. Figure 1 Ruthenium polypyridyl complexes: versatile visible light photocatalysts. The ability of Ru(bpy)32+ and related complexes to function as visible light photocatalysts has been recognized and extensively investigated for applications in inorganic and materials chemistry. In particular, photoredox catalysts have been utilized to accomplish the splitting of water into hydrogen and oxygen4 and the reduction of carbon dioxide to methane.5 Ru(bpy)32+ and its analogues have been used (i) as components of dye sensitized solar cells6 and organic light emitting diodes,7 (ii) to initiate polymerization reactions,8 and (iii) in photo dynamic therapy.9 Until recently, however, these complexes had been only sporadically employed as photocatalysts in the area of organic synthesis. The limited exploration of this area is perhaps surprising, as single electron, radical processes have long been employed in C C bond construction and often provide access to reactivity that is complementary to that of closed shell, two electron pathways.10 In 2008, concurrent reports from the Yoon group and our own lab detailed the use of Ru(bpy)32+ as a visible light photoredox catalyst to perform a [2 2] cycloaddition11 and an a alkylation of aldehydes,12 respectively. Shortly thereafter, Stephenson and co workers disclosed a photoredox reductive dehalogenation of activated alkyl halides mediated by the same catalyst.13 The combined efforts of these three research groups have helped to initiate a renewed interest in this field, prompting a diversity of studies into the utility of photoredox catalysis as a conceptually novel approach to synthetic organic reaction development. Much of the promise of visible light photoredox catalysis hinges on its ability to achieve unique, if not exotic bond constructions that are not possible using established protocols. For instance, photoredox catalysis may be employed to perform overall redox neutral reactions. As both oxidants and reductants may be transiently generated in the same reaction vessel, photoredox approaches may be used to develop reactions requiring both the donation and the reception of electrons at disparate points in the reaction mechanism. This approach stands in contrast to methods requiring stoichiometric chemical oxidants and reductants, which are often incompatible with each other, as well as to electrochemical approaches, which are not amenable to redox neutral transformations. Furthermore, single electron transfer events often provide access to radical ion intermediates having reactivity patterns fundamentally different from those of their ground electronic or excited states.14 Access to these intermediates using other means of activation is often challenging or requires conditions under which their unique reactivity cannot be productively harnessed. At the same time, photoredox catalysts such as Ru(bpy)32+ may also be employed to generate radicals for use in a diverse range of established radical chemistries. Photoredox reactions occur under extremely mild conditions, with most reactions proceeding at room temperature without the need for highly reactive radical initiators. The irradiation source is typically a commercial household light bulb, a significant advantage over the specialized equipment required for processes employing high energy ultraviolet (UV) light. Additionally, because organic molecules generally do not absorb visible light, there is little potential for deleterious side reactions that might arise from photoexcitation of the substrate itself. Finally, photoredox catalysts may be employed at very low loadings, with 1 mole or less being typical. This Review will highlight the early work on the use of transition metal complexes as photoredox catalysts to promote reactions of organic compounds (prior to 2008) as well as cover the surge of work that has appeared since 2008. We have for the most part grouped reactions according to whether the organic substrate undergoes reduction, oxidation, or a redox neutral reaction and throughout have sought to highlight the variety of reactive intermediates that may be accessed via this general reaction manifold.15 Studies on the use of transition metal complexes as visible light photocatalysts for organic synthesis have benefited tremendously from advances in the related fields of organic and semiconductor photocatalysis. Many organic molecules may function as visible light photocatalysts; analogous to metal complexes such as Ru(bpy)32+ organic dyes such as eosin Y, 9,10 dicyanoanthracene, and triphenylpyrylium salts absorb light in the visible region to give excited states capable of single electron transfer. These catalysts have been employed to achieve a vast range of bond forming reactions of broad utility in organic synthesis.16 Visible light photocatalysis has also been carried out with heterogeneous semiconductors such as mesoporous carbon nitride17 and various metal oxides and sulfides.18 These approaches are often complementary to photoredox catalysis with transition metal polypyridyl complexes, and we have referred to work in these areas when it is similar to the chemistry under discussion. However, an in depth discussion of the extensive literature in these fields is outside the scope of this Review, and readers are directed to existing reviews on these topics.16 18", "author_names": [ "Christopher K Prier", "Danica A Rankic", "David W C MacMillan" ], "corpus_id": 206897978, "doc_id": "206897978", "n_citations": 4145, "n_key_citations": 3, "score": 1, "title": "Visible light photoredox catalysis with transition metal complexes: applications in organic synthesis.", "venue": "Chemical reviews", "year": 2013 }, { "abstract": "MicroRNAs (miRNAs) circulate in the bloodstream in a highly stable, extracellular form and are being developed as blood based biomarkers for cancer and other diseases. However, the mechanism underlying their remarkable stability in the RNase rich environment of blood is not well understood. The current model in the literature posits that circulating miRNAs are protected by encapsulation in membrane bound vesicles such as exosomes, but this has not been systematically studied. We used differential centrifugation and size exclusion chromatography as orthogonal approaches to characterize circulating miRNA complexes in human plasma and serum. We found, surprisingly, that the majority of circulating miRNAs cofractionated with protein complexes rather than with vesicles. miRNAs were also sensitive to protease treatment of plasma, indicating that protein complexes protect circulating miRNAs from plasma RNases. Further characterization revealed that Argonaute2 (Ago2) the key effector protein of miRNA mediated silencing, was present in human plasma and eluted with plasma miRNAs in size exclusion chromatography. Furthermore, immunoprecipitation of Ago2 from plasma readily recovered non vesicle associated plasma miRNAs. The majority of miRNAs studied copurified with the Ago2 ribonucleoprotein complex, but a minority of specific miRNAs associated predominantly with vesicles. Our results reveal two populations of circulating miRNAs and suggest that circulating Ago2 complexes are a mechanism responsible for the stability of plasma miRNAs. Our study has important implications for the development of biomarker approaches based on capture and analysis of circulating miRNAs. In addition, identification of extracellular Ago2 miRNA complexes in plasma raises the possibility that cells release a functional miRNA induced silencing complex into the circulation.", "author_names": [ "Jason D Arroyo", "John R Chevillet", "Evan M Kroh", "Ingrid K Ruf", "Colin C Pritchard", "Donald F Gibson", "Patrick S Mitchell", "Christopher F Bennett", "Era L Pogosova-Agadjanyan", "Derek L Stirewalt", "Jonathan F Tait", "Muneesh Tewari" ], "corpus_id": 12959584, "doc_id": "12959584", "n_citations": 2567, "n_key_citations": 94, "score": 0, "title": "Argonaute2 complexes carry a population of circulating microRNAs independent of vesicles in human plasma", "venue": "Proceedings of the National Academy of Sciences", "year": 2011 }, { "abstract": "Most RNAs generated by the human genome have no protein coding ability and are termed non coding RNAs. Among these include circular RNAs, which include exonic circular RNAs (circRNA) mainly found in the cytoplasm, and intronic RNAs (ciRNA) predominantly detected in the nucleus. The biological functions of circular RNAs remain largely unknown, although ciRNAs have been reported to promote gene transcription, while circRNAs may function as microRNA sponges. We demonstrate that the circular RNA circ Foxo3 was highly expressed in non cancer cells and were associated with cell cycle progression. Silencing endogenous circ Foxo3 promoted cell proliferation. Ectopic expression of circ Foxo3 repressed cell cycle progression by binding to the cell cycle proteins cyclin dependent kinase 2 (also known as cell division protein kinase 2 or CDK2) and cyclin dependent kinase inhibitor 1 (or p21) resulting in the formation of a ternary complex. Normally, CDK2 interacts with cyclin A and cyclin E to facilitate cell cycle entry, while p21works to inhibit these interactions and arrest cell cycle progression. The formation of this circ Foxo3 p21 CDK2 ternary complex arrested the function of CDK2 and blocked cell cycle progression.", "author_names": [ "William Weidong Du", "Weining Yang", "Elizabeth Liu", "Zhenguo Yang", "Preet Dhaliwal", "Burton B Yang" ], "corpus_id": 17915036, "doc_id": "17915036", "n_citations": 871, "n_key_citations": 18, "score": 0, "title": "Foxo3 circular RNA retards cell cycle progression via forming ternary complexes with p21 and CDK2", "venue": "Nucleic acids research", "year": 2016 }, { "abstract": "Microtubule nucleation is regulated by the g tubulin ring complex (gTuRC) and related g tubulin complexes, providing spatial and temporal control over the initiation of microtubule growth. Recent structural work has shed light on the mechanism of gTuRC based microtubule nucleation, confirming the long standing hypothesis that the gTuRC functions as a microtubule template. The first crystallographic analysis of a non g tubulin gTuRC component (g tubulin complex protein 4 (GCP4) has resulted in a new appreciation of the relationships among all gTuRC proteins, leading to a refined model of their organization and function. The structures have also suggested an unexpected mechanism for regulating gTuRC activity via conformational modulation of the complex component GCP3. New experiments on gTuRC localization extend these insights, suggesting a direct link between its attachment at specific cellular sites and its activation.", "author_names": [ "Justin M Kollman", "Andreas Merdes", "Lionel Mourey", "David A Agard" ], "corpus_id": 13249200, "doc_id": "13249200", "n_citations": 3063, "n_key_citations": 26, "score": 0, "title": "Microtubule nucleation by g tubulin complexes", "venue": "Nature Reviews Molecular Cell Biology", "year": 2011 }, { "abstract": "We introduce clustering with overlapping neighborhood expansion (ClusterONE) a method for detecting potentially overlapping protein complexes from protein protein interaction data. ClusterONE derived complexes for several yeast data sets showed better correspondence with reference complexes in the Munich Information Center for Protein Sequence (MIPS) catalog and complexes derived from the Saccharomyces Genome Database (SGD) than the results of seven popular methods. The results also showed a high extent of functional homogeneity.", "author_names": [ "Tamas Nepusz", "Haiyuan Yu", "Alberto Paccanaro" ], "corpus_id": 10291802, "doc_id": "10291802", "n_citations": 946, "n_key_citations": 147, "score": 0, "title": "Detecting overlapping protein complexes in protein protein interaction networks", "venue": "Nature Methods", "year": 2012 }, { "abstract": "Subunits of mammalian SWI/SNF (mSWI/SNF or BAF) complexes have recently been implicated as tumor suppressors in human malignancies. To understand the full extent of their involvement, we conducted a proteomic analysis of endogenous mSWI/SNF complexes, which identified several new dedicated, stable subunits not found in yeast SWI/SNF complexes, including BCL7A, BCL7B and BCL7C, BCL11A and BCL11B, BRD9 and SS18. Incorporating these new members, we determined mSWI/SNF subunit mutation frequency in exome and whole genome sequencing studies of primary human tumors. Notably, mSWI/SNF subunits are mutated in 19.6% of all human tumors reported in 44 studies. Our analysis suggests that specific subunits protect against cancer in specific tissues. In addition, mutations affecting more than one subunit, defined here as compound heterozygosity, are prevalent in certain cancers. Our studies demonstrate that mSWI/SNF is the most frequently mutated chromatin regulatory complex (CRC) in human cancer, exhibiting a broad mutation pattern, similar to that of TP53. Thus, proper functioning of polymorphic BAF complexes may constitute a major mechanism of tumor suppression.", "author_names": [ "Cigall Kadoch", "Diana C Hargreaves", "Courtney Hodges", "Laura Elias", "Lena Ho", "Jeffrey A Ranish", "Gerald R Crabtree" ], "corpus_id": 30921367, "doc_id": "30921367", "n_citations": 808, "n_key_citations": 35, "score": 0, "title": "Proteomic and bioinformatic analysis of mammalian SWI/SNF complexes identifies extensive roles in human malignancy", "venue": "Nature Genetics", "year": 2013 }, { "abstract": "The heterogeneous nature of mammalian PRC1 complexes has hindered our understanding of their biological functions. Here, we present a comprehensive proteomic and genomic analysis that uncovered six major groups of PRC1 complexes, each containing a distinct PCGF subunit, a RING1A/B ubiquitin ligase, and a unique set of associated polypeptides. These PRC1 complexes differ in their genomic localization, and only a small subset colocalize with H3K27me3. Further biochemical dissection revealed that the six PCGF RING1A/B combinations form multiple complexes through association with RYBP or its homolog YAF2, which prevents the incorporation of other canonical PRC1 subunits, such as CBX, PHC, and SCM. Although both RYBP/YAF2 and CBX/PHC/SCM containing complexes compact chromatin, only RYBP stimulates the activity of RING1B toward H2AK119ub1, suggesting a central role in PRC1 function. Knockdown of RYBP in embryonic stem cells compromised their ability to form embryoid bodies, likely because of defects in cell proliferation and maintenance of H2AK119ub1 levels.", "author_names": [ "Zhonghua Gao", "Jin Zhang", "Roberto Bonasio", "Francesco Strino", "Ayana Sawai", "Fabio Parisi", "Yuval Kluger", "Danny Reinberg" ], "corpus_id": 5421419, "doc_id": "5421419", "n_citations": 641, "n_key_citations": 90, "score": 0, "title": "PCGF homologs, CBX proteins, and RYBP define functionally distinct PRC1 family complexes.", "venue": "Molecular cell", "year": 2012 }, { "abstract": "A fundamental understanding of the luminescence of Au thiolate nanoclusters (NCs) such as the origin of emission and the size effect in luminescence, is pivotal to the development of efficient synthesis routes for highly luminescent Au NCs. This paper reports an interesting finding of Au(I) thiolate complexes: strong luminescence emission by the mechanism of aggregation induced emission (AIE) The AIE property of the complexes was then used to develop a simple one pot synthesis of highly luminescent Au thiolate NCs with a quantum yield of ~15% Our key strategy was to induce the controlled aggregation of Au(I) thiolate complexes on in situ generated Au(0) cores to form Au(0)@Au(I) thiolate core shell NCs where strong luminescence was generated by the AIE of Au(I) thiolate complexes on the NC surface. We were able to extend the synthetic strategy to other thiolate ligands with added functionalities (in the form of custom designed peptides) The discovery (e.g. identifying the source of emission and the size effect in luminescence) and the synthesis protocols in this study can contribute significantly to better understanding of these new luminescence probes and the development of new synthetic routes.", "author_names": [ "Zhentao Luo", "Xun Yuan", "Yue Yu", "Qingbo Zhang", "David Tai Leong", "Jimmie Lee", "Jianping Xie" ], "corpus_id": 207086565, "doc_id": "207086565", "n_citations": 879, "n_key_citations": 19, "score": 0, "title": "From aggregation induced emission of Au(I) thiolate complexes to ultrabright Au(0)@Au(I) thiolate core shell nanoclusters.", "venue": "Journal of the American Chemical Society", "year": 2012 }, { "abstract": "Higher efficiency in the end use of energy requires substantial progress in lighting concepts. All the technologies under development are based on solid state electroluminescent materials and belong to the general area of solid state lighting (SSL) The two main technologies being developed in SSL are light emitting diodes (LEDs) and organic light emitting diodes (OLEDs) but in recent years, light emitting electrochemical cells (LECs) have emerged as an alternative option. The luminescent materials in LECs are either luminescent polymers together with ionic salts or ionic species, such as ionic transition metal complexes (iTMCs) Cyclometalated complexes of Ir(III) are by far the most utilized class of iTMCs in LECs. Herein, we show how these complexes can be prepared and discuss their unique electronic, photophysical, and photochemical properties. Finally, the progress in the performance of iTMCs based LECs, in terms of turn on time, stability, efficiency, and color is presented.", "author_names": [ "Ruben D Costa", "Enrique Orti", "Henk J Bolink", "Filippo Monti", "Gianluca Accorsi", "Nicola Armaroli" ], "corpus_id": 26654787, "doc_id": "26654787", "n_citations": 697, "n_key_citations": 2, "score": 0, "title": "Luminescent ionic transition metal complexes for light emitting electrochemical cells.", "venue": "Angewandte Chemie", "year": 2012 }, { "abstract": "A Lot of HOTAIR The roles of several classes of small <50 nucleotides) noncoding RNAs are beginning to be defined in molecular detail, whereas the function of most of the long ~200+ nucleotides) intergenic noncoding (linc)RNAs found in most eukaryotic genomes remains something of a mystery. The HOTAIR lincRNA, which is transcribed from the mouse HOXC locus, binds to the Polycomb Repressive Complex 2 (PRC2) and recruits it to HOXD and other genes, where its histone methylase activity acts to repress gene transcription. Tsai et al. (p. 689, published online 8 July) now show that HOTAIR also binds to a histone demethylase enzyme, LSD1, part of the CoREST/REST repressor complex. LSD1 acts to remove transcription activating histone marks, reinforcing the repressive activity of the PRC2 complex. HOTAIR thus functions as a platform for the coordinated binding of PRC2 and LSD1 containing complexes to genes, as revealed in a genome wide analysis of PRC1/CoREST/REST co regulated genes. The long noncoding RNA HOTAIR binds two distinct protein complexes that modify chromatin and repress transcription. Long intergenic noncoding RNAs (lincRNAs) regulate chromatin states and epigenetic inheritance. Here, we show that the lincRNA HOTAIR serves as a scaffold for at least two distinct histone modification complexes. A 5' domain of HOTAIR binds polycomb repressive complex 2 (PRC2) whereas a 3' domain of HOTAIR binds the LSD1/CoREST/REST complex. The ability to tether two distinct complexes enables RNA mediated assembly of PRC2 and LSD1 and coordinates targeting of PRC2 and LSD1 to chromatin for coupled histone H3 lysine 27 methylation and lysine 4 demethylation. Our results suggest that lincRNAs may serve as scaffolds by providing binding surfaces to assemble select histone modification enzymes, thereby specifying the pattern of histone modifications on target genes.", "author_names": [ "Miao-Chih Tsai", "Ohad Manor", "Yue Wan", "Nima Mosammaparast", "Jordon K Wang", "Fei Lan", "Yang Shi", "Eran Segal", "Howard Y Chang" ], "corpus_id": 46248894, "doc_id": "46248894", "n_citations": 2676, "n_key_citations": 134, "score": 0, "title": "Long Noncoding RNA as Modular Scaffold of Histone Modification Complexes", "venue": "Science", "year": 2010 } ]

[ { "abstract": "Abstract Residual pharmaceutical products from hospitals, pharmaceutical companies, animal farms, and through human excreta are deposited in wastewater and reach environmental niches instigating potential ecological toxicity, genotoxicity, and endocrine disruption. Antibiotics and other pharmaceutical products like analgesics and antiinflammatory drugs, contraceptives, beta blockers, lipid regulators, phenols, herbicides, pesticides, and neuroactive compounds may form highly toxic derivatives with chlorine in postchlorinated effluents. Their effects in low concentrations necessitate highly sensitive and specific techniques for their detection. Removal of the residual antibiotics and other pharmaceutical compounds in wastewater and water is beyond the capacities of conventional wastewater treatment plants (WWTPs) Metal oxides are able to form diverse oxide compounds, which due to their structural geometries can exhibit metallic, semiconductor, or insulator characteristics. Nanoscale metal oxides are promising alternative effective adsorbents for the removal of heavy metals, organic derivatives, and radionuclides. Ferric oxide nanomaterials (FO NM) like magnetite, maghemite, hematite, and nanoactivated carbon have been used for efficient removal of a range of other antibiotics from water including sulfamethoxazole as well as phenol and phenol related pharmaceuticals. The combination of iron oxide NM and biochars allows the removal of both pharmaceuticals and microbial contaminants and may become a cheap and effective removal process. The potential of zinc oxide nanoparticles (nZnO) and titanium dioxide nanoparticles (TiO2 NPs) has also been explored for the efficient removal of organic and inorganic pharmaceutical contaminants from wastewater. Doped metal oxide nanoparticles (MONs) are showing higher photocatalytic activity than undoped due to factors including small grain size, high crystallinity, high specific surface area, and decrease in the band gap energy. The doped MONs with additional metals can remove a wide range of pharmaceuticals and personal care products, as well as pathogens from water in a more effective way than the undoped ones, while doping with transition metal ions like Fe2+ Mn2+ Cu2+ Zn2+ among others has been appraised positively for best activity. Several advantages have been attributed to the use of NMs based on the cost implication, ease of use, and flexibility with an assurance of removal of toxic pharmaceutical nanocontaminants from water and the wastewater for reuse. The guidelines of the Inter organization Programme for the Sound Management of Chemicals (developed as a cooperative agreement of UNEP, ILO, FAO, WHO, UNIDO, UNITAR, and OECD) which contain reports, identification, risk, analysis, and preliminary guidance on the use of nanoparticles, should be considered in utilizing MON or any other NMs. This chapter will briefly overview the different types of metal oxides nanomaterials used for the monitoring/removal of the pharmaceutical compounds and personal care products (PPCPs) prevalent in wastewater. Further, the feasibility, challenges, and future perspective of the application of these MONs in the development of efficient wastewater treatment processes will be explored.", "author_names": [ "Anthony Ayodeji Adegoke", "Thor Axel Stenstrom" ], "corpus_id": 145837573, "doc_id": "145837573", "n_citations": 3, "n_key_citations": 0, "score": 1, "title": "Metal oxide nanoparticles in removing residual pharmaceutical products and pathogens from water and wastewater", "venue": "", "year": 2019 }, { "abstract": "Abstract In this work we present results concerning the cluster beam synthesis of metal and metal oxide nanoparticles together with their applications in emerging memories like nanoparticle Flash memories and resistive switching memories. Regarding the former, very large memory windows of 7 8 V are presented at voltages below 10 V using Ni, Pt or Au nanoparticles. Regarding the latter, metal insulator metal devices based upon titanium oxide nanoparticle films show switching voltages well below 1 V with high to low resistance ratios as high as 1000. An in depth analysis of the physical and electrical properties of the titanium oxide nanoparticle films allows to shine light onto the physics behind the switching mechanism.", "author_names": [ "Emanuele Verrelli", "Dimitris Tsoukalas" ], "corpus_id": 5898860, "doc_id": "5898860", "n_citations": 7, "n_key_citations": 0, "score": 0, "title": "Cluster beam synthesis of metal and metal oxide nanoparticles for emerging memories", "venue": "", "year": 2014 }, { "abstract": "The present invention is a sol gel (sol gel) and photo reaction to form and combine the metal oxide nanoparticles in a photocurable transparent polymer by the organic thin film transistor of the change in the electric permittivity using the easy composition in the gate insulator and its relates to the manufacturing method, the invention includes a substrate, a photocurable transparent inorganic polymer composite layer, the organic active layer, and source and drain electrode layers including metal oxide nanoparticles to be formed on the electrode layer, and electrodes formed on the substrate, through the gel and photocuring reaction photocurable transparent inorganic polymer composite layer is spin casting a mixture of the metal oxide precursor and a photo curing transparent polymer (spin casting) after forming an organic film by the sol containing the metal oxide nano particles a portion thereof is converted to a nano inorganic particles provides an organic thin film transistor characterized in that have a dielectric. The organic thin film transistor according to the present invention, the dielectric constant of the gate insulator, and significantly high control is easy compared with the gate insulator that is conventionally used, as well as transparent to retain the characteristics of the photo transparent polymer, the photo furnace can be fine pattern formation It has the advantage of fairness is very good. The sol gel reaction, photocuring, nanotechnology, nano composite material, organic transparent gate insulator, organic thin film transistor", "author_names": [ "" ], "corpus_id": 149733605, "doc_id": "149733605", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Organic thin film transistors comprising metal oxide nanoparticles within transparent polymer gate insulator layer and method for fabricating the same by using sol gel and photocure reactions", "venue": "", "year": 2008 }, { "abstract": "The laser sintering employing a CW DPSS laser was applied to the fabrication of transparent conductive films using silver and indium tin oxide (ITO) nanoparticle inks. The laser sintering of an Ag nanoparticle thin film gave a transparent conductive film with a thickness of ca. 10 nm, whereas such a thin film fabricated by conventional heat treatment using an electronic furnace was insulator because of the formation of isolated silver grains during the slow heating process The influences of the laser sintering conditions such as laser scan speed on the conductivity and the transparency were studied. The laser sintering using ITO nanoparticle ink gave a high transparent conductive film by one step scanning of laser beam in air.", "author_names": [ "Akira Watanabe", "Gang Qin" ], "corpus_id": 119948036, "doc_id": "119948036", "n_citations": 5, "n_key_citations": 0, "score": 0, "title": "Transparent conductive films based on the laser sintering of metal and metal oxide nanoparticles", "venue": "Photonics West Lasers and Applications in Science and Engineering", "year": 2014 }, { "abstract": "Abstract. Microscale optical devices enabled by wireless power harvesting and telemetry facilitate manipulation and testing of localized biological environments (e.g. neural recording and stimulation, targeted delivery to cancer cells) Design of integrated microsystems utilizing optical power harvesting and telemetry will enable complex in vivo applications like actuating a single nerve, without the difficult requirement of extreme optical focusing or use of nanoparticles. Silicon on insulator (SOI) based platforms provide a very powerful architecture for such miniaturized platforms as these can be used to fabricate both optoelectronic and microelectronic devices on the same substrate. Near infrared biomedical optics can be effectively utilized for optical power harvesting to generate optimal results compared with other methods (e.g. RF and acoustic) at submillimeter size scales intended for such designs. We present design and integration techniques of optical power harvesting structures with complementary metal oxide semiconductor platforms using SOI technologies along with monolithically integrated electronics. Such platforms can become the basis of optoelectronic biomedical systems including implants and lab on chip systems.", "author_names": [ "Muhammad Mujeeb-U -Rahman", "Axel Scherer" ], "corpus_id": 5665697, "doc_id": "5665697", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "Silicon on insulator based complementary metal oxide semiconductor integrated optoelectronic platform for biomedical applications", "venue": "Journal of biomedical optics", "year": 2016 }, { "abstract": "A chemical reaction between polyamic acid, a precursor of polyimide known as a stable insulating polymer, and a metal thin film makes metal oxide nanoparticles located in polyimide matrix. In a metal oxide semiconductor (MOS) diode with such nanoparticles and polyimide, the current voltage (I V) characteristics behave abnormally, not showing the general MOS property. The characteristics possibly apply to resistance random access memory (RRAM) In this study, we investigated the conductance and the I V characteristics with temperature modulation that divide the effects of the activation energy. The I V hysteresis from a measured voltage sweep is an interesting physical phenomenon and is useful in many applications.", "author_names": [ "Jae Hoon Kim", "Dong Uk Lee", "Eun Kyu Kim" ], "corpus_id": 95131373, "doc_id": "95131373", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Current voltage characteristics of a metal insulator semiconductor structure containing metal oxide nanoparticles within a polyimide matrix", "venue": "", "year": 2007 }, { "abstract": "The present invention relates to an organic thin film transistor comprising a photocurable transparent inorganic/polymer composite layer as a gate insulator layer in which metal oxide nanoparticles are generated within a photocurable transparent polymer through sol gel and photocuring reactions and whose permittivity is easily regulated; and a fabrication method thereof. Since the organic thin film transistor accord ing to the present invention utilizes the photocurable trans parent inorganic/polymer composite layer showing a signifi cantly high and readily controllable permittivity as a gate insulator, it is capable of operating under low Voltage condi tions and has a high on/off current ratio due to low leakage current. Further, the organic thin film transistor according to the present invention preserves the unique properties of the photocurable transparent polymer, enabling the formation of a photocurable micropattern of a gate insulator having high processibility.", "author_names": [ "Matthew SSmith", "soook 1 2m" ], "corpus_id": 5025595, "doc_id": "5025595", "n_citations": 0, "n_key_citations": 0, "score": 0, "title": "ORGANIC THIN FILMI TRANSISTORS INCLUDING METAL OXDE NANOPARTICLES WITHINA PHOTOCURABLE TRANSPARENT POLYMER GATE INSULATOR LAYER AND METHOD FOR FABRICATING THE SAME BY USING SOL GEL", "venue": "", "year": 2017 }, { "abstract": "Due to excellent metal insulator transition property, vanadium dioxide nanoparticles (VO2 NPs) based nanomaterials are extensively studied and applied in various fields, and thus draw safety concerns of VO2 NPs exposure through various routes. Herein, the cytotoxicity of VO2 NPs (N VO2) and titanium dioxide coated VO2 NPs (T VO2) to typical human lung cell lines (A549 and BEAS 2B) was studied by using a series of biological assays. It was found that both VO2 NPs induced a dose dependent cytotoxicity, and the two cell lines displayed similar sensitivity to VO2 NPs. Under the same conditions, T VO2 NPs showed slightly lower cytotoxicity than N VO2 in both cells, indicating the surface coating of titanium dioxide mitigated the toxicity of VO2 NPs. Titanium dioxide coating changed the surface property of VO2 NPs and reduced the vanadium release of particles, and thus helped lowing the toxicity of VO2 NPs. The induced cell viability loss was attributed to apoptosis and proliferation inhibition, which were supported by the assays of apoptosis, mitochondrial membrane damage, caspase 3 level, and cell cycle arrest. The oxidative stress, i.e. enhanced reactive oxygen species generation and suppressed reduced glutathione in A549 and BEAS 2B cells was one of the major mechanisms of the cytotoxicity of VO2 NPs. These findings provide safety guidance for the practical applications of vanadium dioxide based materials.", "author_names": [ "Wensong Xi", "Huan Tang", "Yuanyuan Liu", "Chun-Yuan Liu", "Yanfeng Gao", "Aoneng Cao", "Yuanfang Liu", "Zhang Chen", "Haifang Wang" ], "corpus_id": 209462845, "doc_id": "209462845", "n_citations": 9, "n_key_citations": 0, "score": 0, "title": "Cytotoxicity of vanadium oxide nanoparticles and titanium dioxide coated vanadium oxide nanoparticles to human lung cells", "venue": "Journal of applied toxicology JAT", "year": 2019 }, { "abstract": "The coupling of the localized surface plasmon resonance of Au nanoparticles is utilized to deliver a visible light stimulus to control conduction at the LaAlO3 /SrTiO3 interface. A giant photoresponse and the controllable metal insulator transition are characterized at this heterointerface. This study paves a new route to optical control of the functionality at the heterointerfaces.", "author_names": [ "Jheng-Cyuan Lin", "Vu Thanh Tra", "Dung-Sheng Tsai", "Tai-Te Lin", "Po-Cheng Huang", "Wei-Lun Hsu", "Hui Jun Wu", "Rong Huang", "Nguyen Van Chien", "Ryuji Yoshida", "Jiunn-Yuan Lin", "Yuichi Ikuhara", "Y P Chiu", "Shangjr Gwo", "Din Ping Tsai", "Jr-hau He", "Y H Chu" ], "corpus_id": 205263707, "doc_id": "205263707", "n_citations": 11, "n_key_citations": 0, "score": 0, "title": "Control of the Metal Insulator Transition at Complex Oxide Heterointerfaces through Visible Light.", "venue": "Advanced materials", "year": 2016 }, { "abstract": "Metal insulator transition (MIT) in strongly correlated electronic materials has enormous potential with scientific and technological impacts in future oxide nanoelectronic devices. Although photo induced MIT can provide opportunities to extend the novel functionality of strongly correlated electronic materials, there have rarely been reports on it. Here, we report MIT provoked by visible near infrared light in Ag decorated VO2 nanorod arrays (NRs) because of localized surface plasmon resonance (LSPR) and its application to broadband photodetectors. Our simulation results based on the finite difference time domain method show that the electric field resulting from LSPR can be generated at the interface between Ag nanoparticles and VO2 layers under vis NIR illumination. Using high resolution transmission electronic microscopy and Raman spectroscopy, we observe the MIT and structural phase transition in the Ag decorated VO2 NRs due to the LSPR effect. The optoelectronic measurements confirm that high, fast, and broad photoresponse of Ag decorated VO2 NRs is attributed to photo induced MIT due to LSPR. Our study will open up a new strategy to trigger MIT in strongly correlated electronic materials through functionalization with plasmonic nanoparticles and serve as a valuable proof of concept for next generation optoelectronic devices with fast response, low power consumption, and high performance.", "author_names": [ "Kootak Hong", "Cheon Woo Moon", "Jun Min Suh", "Tae Hyung Lee", "Seong-il Kim", "Sanghan Lee", "Ho Won Jang" ], "corpus_id": 73475801, "doc_id": "73475801", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Daylight Induced Metal Insulator Transition in Ag Decorated Vanadium Dioxide Nanorod Arrays.", "venue": "ACS applied materials interfaces", "year": 2019 } ]

[ { "abstract": "We report on the dissipative soliton (DS) trapping in a fiber ring laser mode locked with a semiconductor saturable absorber mirror and operated in normal dispersion regime. It was shown that despite the fact that a DS is strongly frequency chirped, two DSs formed along the two orthogonal polarization directions of a birefringent cavity fiber laser can incoherently couple and travel with the same group velocity in the laser. Numerical simulations have well confirmed the experimental observations.", "author_names": [ "L M Zhao", "D Y Tang", "X Wu", "Han Zhang" ], "corpus_id": 39092423, "doc_id": "39092423", "n_citations": 36, "n_key_citations": 0, "score": 1, "title": "Dissipative soliton trapping in normal dispersion fiber lasers.", "venue": "Optics letters", "year": 2010 }, { "abstract": "Rapid progress in real time spectroscopy uncovers the spatio spectral scenarios of ultrashort pulses in dissipative systems. Varieties of transient soliton dynamics on different timescales have been revealed. Here, we report on an experimental observation of stationary and pulsating vector dissipative solitons in a nonlinear multimode interference (NL MMI) based fiber laser with net normal dispersion. Polarization non discrimination of the NL MMI mode locking facilitates the dissipative soliton trapping process. Two orthogonally polarized components are coupled together through oppositely shifting their central frequencies to form the group velocity locked vector dissipative solitons (GVLVDSs) Dispersive Fourier transform (DFT) based polarization resolved measurement enables insights into the transient polarization dynamics and the long term evolution. Particularly, both stationary and pulsating GVLVDSs are obtained with appropriate parameter settings. It is found that the quasi stationary pulsating manner is accompanied with recurrent spectral breathing and energy oscillation; the two orthogonally polarized components possess synchronous pulsating manners due to the cross phase modulation induced trapping mechanism and the similar formation process. Additionally, chaotic pulsation is also captured in sense that the spectra cannot recover to their original profiles despite of the harmonic energy oscillation. All these findings can enhance our understanding towards soliton pulsation with the freedom of vectorial degree.", "author_names": [ "Yiyang Luo", "Yang Xiang", "Perry Ping Shum", "Yusong Liu", "Ran Xia", "Wenjun Ni", "Huy Quoc Lam", "Qizhen Sun", "Xiahui Tang" ], "corpus_id": 211832804, "doc_id": "211832804", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Stationary and pulsating vector dissipative solitons in nonlinear multimode interference based fiber lasers.", "venue": "Optics express", "year": 2020 }, { "abstract": "Abstract In this article, the peak power expression of dissipative soliton resonance (DSR) pulse is derived, in a normal dispersion fiber laser, by using the equation for the resonance curve and the relationship between the parameters of cubic quintic complex Ginzburg Landau (CGLQ) equation and the cavity parameters. According to the peak power expression, the peak power of DSR pulses is inversely proportional to the average dispersion and the square of the gain bandwidth, is proportional to the square of the saturation power. That is to say, we can improve the peak power of DSR pulse in three ways: Firstly, increase the saturation power in the case of sinusoidal saturable absorber transmission curve; secondly, decrease the gain bandwidth properly; thirdly, decrease the average dispersion suitably. In addition, the further results of numerical simulations are obtained by using pulse tracing technique, which are in good agreement with the theoretical derivation of peak power of DSR pulses. This means that our work can serve as a guideline to design high peak power DSR fiber laser.", "author_names": [ "Chuyan Liu", "Qianchao Wu", "Yong Yao", "Chonghao Wu", "Yaping Gan", "Yanping Fu", "Yanfu Yang", "Jiajun Tian", "Ke Xu" ], "corpus_id": 224891141, "doc_id": "224891141", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Numerical research on the dissipative soliton resonance peak power in normal dispersion fiber lasers", "venue": "", "year": 2020 }, { "abstract": "Internal polarization dynamics of vector dissipative soliton resonance (DSR) pulses in a mode locked fiber laser are investigated. By utilizing a wave plate analyzer configuration to analyze the special structure of a DSR pulse, we find that polarization state is not uniform across a resonant dissipative soliton. Specifically, although the central plane wave of the resonant dissipative soliton acquires nearly a single fixed polarization, the dissipative fronts feature polarization states that are different and spatially varying. This distinct polarization distribution is maintained while the whole soliton extends with increasing gain. Numerical simulation further confirms the experimental observations.", "author_names": [ "Daojing Li", "Deyuan Shen", "Lei Li", "Dingyuan Tang", "Lei Su", "Luming Zhao" ], "corpus_id": 4005659, "doc_id": "4005659", "n_citations": 12, "n_key_citations": 1, "score": 0, "title": "Internal polarization dynamics of vector dissipative soliton resonance pulses in normal dispersion fiber lasers.", "venue": "Optics letters", "year": 2018 }, { "abstract": "We report on an all normal dispersion Yb doped fiber laser with mode locking mechanism based on nonlinear polarization rotation. The splitting and trapping of dissipative solitons (DSs) could be observed by inserting of a short section of polarization maintaining fiber in cavity configuration as an in line birefringence fiber filter. Two trapped orthogonal polarization DSs can travel with the same group velocity in the laser cavity. With the DSs trapping, the polarization sidebands are appeared in the spectrum. The trapping of DSs and sideband generation is numerically simulated as well.", "author_names": [ "Zhongwei Xu", "Xing Luo", "Kuan Fu", "Luyun Yang", "Haiqing Li", "Jinyan Li" ], "corpus_id": 21844333, "doc_id": "21844333", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Dissipative Soliton Trapping in an All Normal Dispersion Mode Locked Yb Doped Fiber Laser", "venue": "IEEE Photonics Technology Letters", "year": 2017 }, { "abstract": "Numerical simulations on dissipative soliton resonance generation in an all normal dispersion fiber ring laser are presented. Situations with monotonic and periodical saturable absorption are both considered. The multipulse operation in dissipative soliton laser is found to be caused by the spectral filtering effect that limits the spectral maximum width, and the multipulsing can be fully circumvent by inducing strong peak power clamping effect of a sinusoidal saturable absorber in the cavity. When the cavity peak power clamping effect is strong enough that the pulse peak power and the pulse spectral width are both confined at a low value, the spectral filtering effect induced multipulse operation is prevented and the dissipative soliton resonance is generated. Otherwise, the spectral filtering effect causes pulse breaking before the pulse peak power reaches the saturation point. Further results show that under the dissipative soliton resonance, the generated pulse peak power can be directly controlled by the cavity peak power clamping effect, which is determined by the saturation power of the saturable absorber.", "author_names": [ "Daojing Li", "Dingyuan Tang", "Luming Zhao", "Deyuan Shen" ], "corpus_id": 19271349, "doc_id": "19271349", "n_citations": 69, "n_key_citations": 5, "score": 0, "title": "Mechanism of Dissipative Soliton Resonance Generation in Passively Mode Locked All Normal Dispersion Fiber Lasers", "venue": "Journal of Lightwave Technology", "year": 2015 }, { "abstract": "In this paper, we propose a photonic crystal fiber with broadband ultra flattened normal dispersion at 2 mm. In this fiber, a subwavelength air hole in the core region and air holes arrangement in the cladding region are used to control the property of dispersion. With optimized design, the dispersion of the proposed ultra flattened normal dispersion fiber (UNDF) can be kept within 72.4 to 73.15 ps*nm 1km 1 from 1750 to 2350 nm wavelength. Benefiting from this advantage, the fiber shows great potential in the applications of coherent supercontinuum (SC) generation and dissipative soliton resonance (DSR) generation in thulium doped fiber lasers. According to our investigation, coherent SC with 10 dB bandwidth of 238 nm can be obtained by using 50 cm UNDF. Furthermore, by constructing a UNDF based nonlinear optical loop mirror as a saturable absorber, we specifically investigate the field evolution from dissipative soliton to DSR in passively mode locked lasers. The proposed UNDF can be a key component for various laser sources in a 2 mm band.", "author_names": [ "Tianye Huang", "Qian Wei", "Zhichao Wu", "Xu Wu", "Pan Huang", "Zhuo Cheng", "Perry Ping Shum" ], "corpus_id": 164651984, "doc_id": "164651984", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Ultra Flattened Normal Dispersion Fiber for Supercontinuum and Dissipative Soliton Resonance Generation at 2 mm", "venue": "IEEE Photonics Journal", "year": 2019 }, { "abstract": "We numerically investigated the compressibility of dissipative soliton pulses in an all normal dispersion fiber laser which was mode locked with a nonlinear optical loop mirror. A transition state within the area between the traditional dissipative soliton regime and dissipative soliton resonance regime was revealed to have much higher dechirped peak power and shorter dechirped pulse duration than its vicinity. This phenomenon is reported for the first time to the best of our knowledge. The peak power and pulse width of the dechirped pulse were calculated using the linear compression method. The dynamics and the distribution of the transition state were systematically analyzed in laser parameter spaces. The nonlinear frequency chirp was mainly induced by self phase modulation and the pulse formation mechanism, which influenced the linear compressibility of the dissipative. We demonstrated that there were optimal filter bandwidth values corresponding to the best pulse compressibility under different laser parameters. The simulation results indicate that dechirped pulses with a pulse peak power of 0.5 1 MW, a pulse duration of the 100 fs level, and a pulse energy of ~100 nJ can be obtained using the optimal parameters.", "author_names": [ "Jun-Hao Cai", "He Chen", "Sheng-Ping Chen", "Jing Hou" ], "corpus_id": 3798311, "doc_id": "3798311", "n_citations": 6, "n_key_citations": 0, "score": 0, "title": "Compressibility of Dissipative Solitons in Mode Locked All Normal Dispersion Fiber Lasers", "venue": "Journal of Lightwave Technology", "year": 2018 }, { "abstract": "Multiple dissipative soliton operation is numerically found to be caused by the spectral filtering effect. Strong peak power clamping effect is required for the dissipative soliton resonance generation. The peak power is controlled by the cavity peak power clamping effect.", "author_names": [ "D J Li", "L M Zhao", "D Y Tang", "Deyuan Shen" ], "corpus_id": 46279807, "doc_id": "46279807", "n_citations": 1, "n_key_citations": 0, "score": 0, "title": "Dissipative soliton resonance in all normal dispersion fiber lasers", "venue": "2015 11th Conference on Lasers and Electro Optics Pacific Rim (CLEO PR)", "year": 2015 }, { "abstract": "We report on the generation of dispersion managed dissipative soliton and various structural soliton molecules from a slight normal dispersion fiber laser. The laser was capable of generating 56.5 nm broad dissipative solitons with quasi rectangular spectral profile. Furthermore, the broadest top flat spectrum with up to 71.4 nm bandwidth was achieved in the noise like pulse regime, operating in the 1542 1613.4 nm. More importantly, by manipulating the laser cavity parameters, various types of soliton molecules, including conventional and unusual structural soliton molecules, were observed in fiber laser. The soliton molecules exhibit different features in autocorrelation traces, which are found to be related to soliton number, soliton intensity and soliton separation within the soliton molecules. The results contribute to enriching the soliton dynamics in the fiber lasers in the slight normal dispersion regime.", "author_names": [ "Xu-De Wang", "Mengqiu Sun", "Simin Yang", "Jie-Yu Pan", "Suwen Li" ], "corpus_id": 226293124, "doc_id": "226293124", "n_citations": 2, "n_key_citations": 0, "score": 0, "title": "Broadband Dispersion Managed Dissipative Soliton and Structural Soliton Molecules in a Slight Normal Dispersion Fiber Laser", "venue": "IEEE Photonics Journal", "year": 2020 } ]