Can Ni phosphides become viable hydroprocessing catalysts?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soled, S.; Miseo, S.; Baumgartner, J.

2015-05-15

We prepared higher surface area nickel phosphides than are normally found by reducing nickel phosphate. To do this, we hydrothermally synthesized Ni hydroxy phosphite precursors with low levels of molybdenum substitution. The molybdenum substitution increases the surface area of these precursors. During pretreatment in a sulfiding atmosphere (such as H2S/H2) dispersed islands of MoS2 segregate from the precursor and provide a pathway for H2 dissociation that allows reduction of the phosphite precursor to nickel phosphide at substantially lower temperatures than in the absence of MoS2. The results reported here show that to create nickel phosphides with comparable activity to conventionalmore » supported sulfide catalysts, one would have to synthesize the phosphide with surface areas exceeding 400 m2/g (i.e. with nanoparticles less than 30 Å in lateral dimension).« less

Porous Cobalt Phosphide Polyhedrons with Iron Doping as an Efficient Bifunctional Electrocatalyst.

PubMed

Li, Feng; Bu, Yunfei; Lv, Zijian; Mahmood, Javeed; Han, Gao-Feng; Ahmad, Ishfaq; Kim, Guntae; Zhong, Qin; Baek, Jong-Beom

2017-10-01

Iron (Fe)-doped porous cobalt phosphide polyhedrons are designed and synthesized as an efficient bifunctional electrocatalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The synthesis strategy involves one-step route for doping foreign metallic element and forming porous cobalt phosphide polyhedrons. With varying doping levels of Fe, the optimized Fe-doped porous cobalt phosphide polyhedron exhibits significantly enhanced HER and OER performances, including low onset overpotentials, large current densities, as well as small Tafel slopes and good electrochemical stability during HER and OER. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Future Directions for Selected Topics in Physics and Materials Science

DTIC Science & Technology

2012-07-12

referred to as lightides (e.g. borides , nitrides, phosphides) • Materials for energy conversion, energy storage, energy transport and energy production...Distributed nanosystems and sensors • Strategy for multilayered combinatorics • lightides ( borides , nitrides, phosphides, • New applications for...Strategy for multilayered combinatorics Lightides ( borides , nitrides, phosphides) • Energy conversion, .storage and production • Precision control

Optimal design study of high efficiency indium phosphide space solar cells

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Flood, Dennis J.

1990-01-01

Recently indium phosphide solar cells have achieved beginning of life AMO efficiencies in excess of 19 pct. at 25 C. The high efficiency prospects along with superb radiation tolerance make indium phosphide a leading material for space power requirements. To achieve cost effectiveness, practical cell efficiencies have to be raised to near theoretical limits and thin film indium phosphide cells need to be developed. The optimal design study is described of high efficiency indium phosphide solar cells for space power applications using the PC-1D computer program. It is shown that cells with efficiencies over 22 pct. AMO at 25 C could be fabricated by achieving proper material and process parameters. It is observed that further improvements in cell material and process parameters could lead to experimental cell efficiencies near theoretical limits. The effect of various emitter and base parameters on cell performance was studied.

Indium phosphide space solar cell research: Where we are and where we are going

NASA Technical Reports Server (NTRS)

Jain, R. K.; Flood, D. J.; Weinberg, Irving

1995-01-01

Indium phosphide is considered to be a strong contender for many photovoltaic space applications because of its radiation resistance and its potential for high efficiency. An overview of recent progress is presented, and possible future research directions for indium phosphide space solar cells are discussed. The topics considered include radiation damage studies and space flight experiments.

Electron emitting device and method of making the same

DOEpatents

Olsen, Gregory Hammond; Martinelli, Ramon Ubaldo; Ettenberg, Michael

1977-04-19

A substrate of single crystalline gallium arsenide has on a surface thereof a layer of single crystalline indium gallium phosphide. A layer of single crystalline gallium arsenide is on the indium gallium phosphide layer and a work function reducing material is on the gallium arsenide layer. The substrate has an opening therethrough exposing a portion of the indium gallium phosphide layer.

Use of continuous renal replacement therapy in acute aluminum phosphide poisoning: a novel therapy.

PubMed

Nasa, Prashant; Gupta, Ankur; Mangal, Kishore; Nagrani, S K; Raina, Sanjay; Yadav, Rohit

2013-09-01

Aluminum phosphide is most common cause of poisoning in northern India. There is no specific antidote available and management of such cases is mainly supportive with high mortality. We present two cases of severe acute aluminium phosphide poisoning where continuous renal replacement therapy (CRRT) was started early along with other resuscitative measures and both the patients survived.

Novel p-n heterojunction copper phosphide/cuprous oxide photocathode for solar hydrogen production.

PubMed

Chen, Ying-Chu; Chen, Zhong-Bo; Hsu, Yu-Kuei

2018-08-01

A Copper phosphide (Cu 3 P) micro-rod (MR) array, with coverage by an n-Cu 2 O thin layer by electrodeposition as a photocathode, has been directly fabricated on copper foil via simple electro-oxidation and phosphidation for photoelectrochemical (PEC) hydrogen production. The morphology, structure, and composition of the Cu 3 P/Cu 2 O heterostructure are systematically analyzed using a scanning electron microscope (SEM), X-ray diffraction and X-ray photoelectron spectra. The PEC measurements corroborate that the p-Cu 3 P/n-Cu 2 O heterostructural photocathode illustrates efficient charge separation and low charge transfer resistance to achieve the highest photocurrent of 430 μA cm -2 that is greater than other transition metal phosphide materials. In addition, a detailed energy diagram of the p-Cu 3 P/n-Cu 2 O heterostructure was investigated using Mott-Schottky analysis. Our study paves the way to explore phosphide-based materials in a new class for solar energy applications. Copyright © 2018 Elsevier Inc. All rights reserved.

Thin boron phosphide coating as a corrosion-resistant layer

DOEpatents

Not Available

1982-08-25

A surface prone to corrosion in corrosive environments is rendered anticorrosive by CVD growing a thin continuous film, e.g., having no detectable pinholes, thereon, of boron phosphide. In one embodiment, the film is semiconductive. In another aspect, the invention is an improved photoanode, and/or photoelectrochemical cell with a photoanode having a thin film of boron phosphide thereon rendering it anticorrosive, and providing it with unexpectedly improved photoresponsive properties.

Intentional fatal metallic phosphide poisoning in a dog--a case report.

PubMed

Nagy, Andras-Laszlo; Bolfa, Pompei; Mihaiu, Marian; Catoi, Cornel; Oros, Adrian; Taulescu, Marian; Tabaran, Flaviu

2015-07-23

Metallic phosphides are extremely toxic pesticides that are regulated in their usage. Information concerning the impact of metallic phosphides on human health is abundant. Data regarding the clinical pathology of phosphide poisoning in humans or domestic and wild animals is largely incomplete with only a few cases of metallic phosphide poisoning being reported every year, especially in humans. For the majority of cases reported in dogs the data are vague or incomplete. Here we report a complete and detailed description of pathological changes in a case of intentional metallic phosphide poisoning in a dog including an exhaustive examination of the brain. A 1 year old, male, Belgian Shepherd crossbreed dog with a clean medical history and no observed clinical signs prior to death, was submitted for post mortem examination. The dog was found dead by the owner. Near the body a suspect mix of bread, fat and a blackish powder was found. The owner announced the authorities and submitted the animal and the possible bait for forensic examination. At necropsy, multisystemic necrotic and degenerative lesions were observed. Histological exam confirmed the presence of necrotic and degenerative lesions of variable severity in all of the examined organs. The toxicological forensic examination revealed the presence of the phosphine gas in the gastric content and the bait. Metallic phosphide poisoning is a rarely reported entity, since the diagnosis of intentional poisoning with these compounds is a great challenge for forensic pathologists and toxicologists. To our knowledge, this is the first study describing the lesions completely in veterinary forensic toxicology. We assume that the toxic shows systemic endotheliotropism and damage of the endothelial cells responsible for the hemorrhagic lesions and for the secondary ischemic necrosis in various organs. This report will contribute to a better understanding of the pathogenesis in cases of acute metallic phosphide exposure in animals.

Method of synthesizing bulk transition metal carbide, nitride and phosphide catalysts

DOEpatents

Choi, Jae Soon; Armstrong, Beth L; Schwartz, Viviane

2015-04-21

A method for synthesizing catalyst beads of bulk transmission metal carbides, nitrides and phosphides is provided. The method includes providing an aqueous suspension of transition metal oxide particles in a gel forming base, dropping the suspension into an aqueous solution to form a gel bead matrix, heating the bead to remove the binder, and carburizing, nitriding or phosphiding the bead to form a transition metal carbide, nitride, or phosphide catalyst bead. The method can be tuned for control of porosity, mechanical strength, and dopant content of the beads. The produced catalyst beads are catalytically active, mechanically robust, and suitable for packed-bed reactor applications. The produced catalyst beads are suitable for biomass conversion, petrochemistry, petroleum refining, electrocatalysis, and other applications.

Gallium phosphide nanowires as a substrate for cultured neurons.

PubMed

Hällström, Waldemar; Mårtensson, Thomas; Prinz, Christelle; Gustavsson, Per; Montelius, Lars; Samuelson, Lars; Kanje, Martin

2007-10-01

Dissociated sensory neurons were cultured on epitaxial gallium phosphide (GaP) nanowires grown vertically from a gallium phosphide surface. Substrates covered by 2.5 microm long, 50 nm wide nanowires supported cell adhesion and axonal outgrowth. Cell survival was better on nanowire substrates than on planar control substrates. The cells interacted closely with the nanostructures, and cells penetrated by hundreds of wires were observed as well as wire bending due to forces exerted by the cells.

Photoelectrochemical cell having photoanode with thin boron phosphide coating as a corrosion resistant layer

DOEpatents

Baughman, Richard J.; Ginley, David S.

1984-01-01

A surface prone to corrosion in corrosive environments is rendered anticorrosive by CVD growing a thin continuous film, e.g., having no detectable pinholes, thereon, of boron phosphide. In one embodiment, the film is semiconductive. In another aspect, the invention is an improved photoanode, and/or photoelectrochemical cell with a photoanode having a thin film of boron phosphide thereon rendering it anitcorrosive, and providing it with unexpectedly improved photoresponsive properties.

Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide

NASA Astrophysics Data System (ADS)

Fang, Si-Ling; Chou, Tsu-Chin; Samireddi, Satyanarayana; Chen, Kuei-Hsien; Chen, Li-Chyong; Chen, Wei-Fu

2017-03-01

Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP2 crystal phase is formed which enhances the electrochemical activity.

Yellow phosphorus-induced Brugada phenocopy.

PubMed

Dharanipradab, Mayakrishnan; Viswanathan, Stalin; Kumar, Gokula Raman; Krishnamurthy, Vijayalatchumy; Stanley, Daphene Divya

Metallic phosphides (of aluminum and phosphide) and yellow phosphorus are commonly used rodenticide compounds in developing countries. Toxicity of yellow phosphorus mostly pertains to the liver, kidney, heart, pancreas and the brain. Cardiotoxicity with associated Brugada ECG pattern has been reported only in poisoning with metallic phosphides. Brugada phenocopy and hepatic dysfunction were observed in a 29-year-old male following yellow phosphorus consumption. He had both type 1 (day1) and type 2 (day2) Brugada patterns in the electrocardiogram, which resolved spontaneously by the third day without hemodynamic compromise. Toxins such as aluminum and zinc phosphide have been reported to induce Brugada ECG patterns due to the generation of phosphine. We report the first case of yellow phosphorus-related Brugada phenocopy, without hemodynamic compromise or malignant arrhythmia. Copyright © 2017 Elsevier Inc. All rights reserved.

Synthesis and catalytic activity of the metastable phase of gold phosphide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernando, Deshani; Nigro, Toni A.E.; Dyer, I.D.

Recently, transition metal phosphides have found new applications as catalysts for the hydrogen evolution reaction that has generated an impetus to synthesize these materials at the nanoscale. In this work, Au{sub 2}P{sub 3} was synthesized utilizing the high temperature decomposition of tri-n-octylphosphine as a source of elemental phosphorous. Gold nanorods were used as morphological templates with the aim of controlling the shape and size of the resulting gold phosphide particles. We demonstrate that the surface capping ligand of the gold nanoparticle precursors can influence the purity and extent to which the gold phosphide phase will form. Gold nanorods functionalized withmore » 1-dodecanethiol undergo digestive ripening to produce discrete spherical particles that exhibit reduced reactivity towards phosphorous, resulting in low yields of the gold phosphide. In contrast, gold phosphide was obtained as a phase pure product when cetyltrimethylammonium bromide functionalized gold nanorods are used instead. The Au{sub 2}P{sub 3} nanoparticles exhibited higher activity than polycrystalline gold towards the hydrogen evolution reaction. - Graphical abstract: Au{sub 2}P{sub 3} was synthesized utilizing the high temperature decomposition of tri-n-octylphosphine as a source of elemental phosphorous and gold nanoparticles as reactants. We demonstrate that the surface capping ligand of the gold nanoparticle precursors influence the purity and extent to which the Au{sub 2}P{sub 3} phase will form. Gold nanorods functionalized with 1-dodecanethiol undergo digestive ripening to produce discrete spherical particles that exhibit reduced reactivity towards phosphorous, resulting in low yields of the gold phosphide. In contrast, gold phosphide was obtained as a phase pure product when cetyltrimethylammonium bromide functionalized gold nanoparticles are used instead. The Au{sub 2}P{sub 3} nanoparticles exhibited higher activity than polycrystalline gold towards the hydrogen evolution reaction. - Highlights: • The surface chemistry of gold affects the synthetic yields of Au{sub 2}P{sub 3}. • Imaging of Au{sub 2}P{sub 3} with transmission electron microscopy results in decomposition. • Au{sub 2}P{sub 3} nanoparticles exhibit activity towards the hydrogen evolution reaction.« less

A Facile Molecular Precursor Route to Metal Phosphide Nanoparticles and Their Evaluation as Hydrodeoxygenation Catalysts

DOE PAGES

Habas, Susan E.; Baddour, Frederick G.; Ruddy, Daniel A.; ...

2015-11-05

Metal phosphides have been identified as a promising class of materials for the catalytic upgrading of bio-oils, which are renewable and potentially inexpensive sources for liquid fuels. Herein, we report the facile synthesis of a series of solid, phase-pure metal phosphide nanoparticles (NPs) (Ni 2P, Rh 2P, and Pd 3P) utilizing commercially available, air-stable metal–phosphine complexes in a one-pot reaction. This single-source molecular precursor route provides an alternative method to access metal phosphide NPs with controlled phases and without the formation of metal NP intermediates that can lead to hollow particles. The formation of the Ni 2P NPs was shownmore » to proceed through an amorphous Ni–P intermediate, leading to the desired NP morphology and metal-rich phase. This low-temperature, rapid route to well-defined metal NPs is expected to have broad applicability to a variety of readily available or easily synthesized metal–phosphine complexes with high decomposition temperatures. Hydrodeoxygenation of acetic acid, an abundant bio-oil component, was performed to investigate H 2 activation and deoxygenation pathways under conditions that are relevant to ex situ catalytic fast pyrolysis (high temperatures, low pressures, and near-stoichiometric H 2 concentrations). The catalytic performance of the silica-supported metal phosphide NPs was compared to the analogous incipient wetness (IW) metal and metal phosphide catalysts over the range 200–500 °C. Decarbonylation was the primary pathway for H 2 incorporation in the presence of all of the catalysts except NP-Pd 3P, which exhibited minimal productive activity, and IW-Ni, which evolved H 2. The highly controlled NP-Ni2P and NP-Rh2P catalysts, which were stable under these conditions, behaved comparably to the IW-metal phosphides, with a slight shift to higher product onset temperatures, likely due to the presence of surface ligands. Most importantly, the NP-Ni 2P catalyst exhibited H 2 activation and incorporation, in contrast to IW-Ni, indicating that the behavior of the metal phosphide is significantly different from that of the parent metal, and more closely resembles that of noble metal catalysts.« less

Structure-Activity Relationships for Pt-Free Metal Phosphide Hydrogen Evolution Electrocatalysts.

PubMed

Owens-Baird, Bryan; Kolen'ko, Yury V; Kovnir, Kirill

2018-05-23

In the field of renewable energy, the splitting of water into hydrogen and oxygen fuel gases using water electrolysis is a prominent topic. Traditionally, these catalytic processes have been performed by platinum-group metal catalysts, which are effective at promoting water electrolysis but expensive and rare. The search for an inexpensive and Earth-abundant catalyst has led to the development of 3d-transition-metal phosphides for the hydrogen evolution reaction. These catalysts have shown excellent activity and stability. In this review, we discuss the electronic and crystal structures of bulk and surface of selected Fe, Co, and Ni phosphides, and their relationships to the experimental catalytic activity. The various synthetic protocols towards the state-of-the-art transition metal phosphide electrocatalysts are also discussed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lattice Matched Carbide–Phosphide Composites with Superior Electrocatalytic Activity and Stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regmi, Yagya N.; Roy, Asa; King, Laurie A.

Composites of electrocatalytically active transition-metal compounds present an intriguing opportunity toward enhanced activity and stability. Here, to identify potentially scalable pairs of a catalytically active family of compounds, we demonstrate that phosphides of iron, nickel, and cobalt can be deposited on molybdenum carbide to generate nanocrystalline heterostructures. Composites synthesized via solvothermal decomposition of metal acetylacetonate salts in the presence of highly dispersed carbide nanoparticles show hydrogen evolution activities comparable to those of state-of-the-art non-noble metal catalysts. Investigation of the spent catalyst using high resolution microscopy and elemental analysis reveals that formation of carbide–phosphide composite prevents catalyst dissolution in acid electrolyte.more » Lattice mismatch between the two constituent electrocatalysts can be used to rationally improve electrochemical stability. Among the composites of iron, nickel, and cobalt phosphide, iron phosphide displays the lowest degree of lattice mismatch with molybdenum carbide and shows optimal electrochemical stability. Turnover rates of the composites are higher than that of the carbide substrate and compare favorably to other electrocatalysts based on earth-abundant elements. Lastly, our findings will inspire further investigation into composite nanocrystalline electrocatalysts that use molybdenum carbide as a stable catalyst support.« less

Responses of Siberian ferrets to secondary zinc phosphide poisoning

USGS Publications Warehouse

Hill, E.F.; Carpenter, J.W.

1982-01-01

The hazard of operational-type applications of zinc phosphide (Zn3P2) on a species closely related to the black-footed ferret (Mustela nigripes), was evaluated by feeding 16 Siberian ferrets (M. eversmanni) rats that had been killed by consumption of 2% zinc phosphide treated bait or by an oral dose of 40, 80, or 160 mg of Zn3P2. All ferrets accepted rats and a single emesis by each of 3 ferrets was the only evidence of acute intoxication. All ferrets learned to avoid eating gastrointestinal tracts of the rats. Subacute zinc phosphide toxicity in the ferrets was indicated by significant decreases (18-48%) in hemoglobin, increases of 35-91 % in serum iron, and elevated levels of serum globulin, cholesterol, and triglycerides. Hemoglobin/iron, urea nitrogen/creatinine, and albumin/globulin ratios also were altered by the treatments. This study demonstrated that Siberian ferrets, or other species with a sensitive emetic reflex, are afforded a degree of protection from acute zinc phosphide poisoning due to its emetic action. The importance of toxicity associated with possible respiratory, liver, and kidney damage indicated by altered blood chemistries is not known.

Scalable and Tunable Carbide-Phosphide Composite Catalyst System for the Thermochemical Conversion of Biomass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regmi, Yagya; Rogers, Bridget; Labbe, Nicole

We have prepared composite materials of hexagonal nickel phosphide and molybdenum carbide (Mo2C) utilizing a simple and scalable two-stage synthesis method comprised of carbothermic reduction followed by hydrothermal incubation. We observe the monophasic hexagonal phosphide Ni2P in the composite at low phosphide-to-carbide (P:C) ratios. Upon increasing the proportion of P:C, the carbide surface becomes saturated, and we detect the emergence of a second hexagonal nickel phosphide phase (Ni5P4) upon annealing. We demonstrate that vapor-phase upgrading (VPU) of whole biomass via catalytic fast pyrolysis is achievable using the composite material as a catalyst, and we monitor the resulting product slates usingmore » pyrolysis gas chromatography/mass spectrometry. Our analysis of the product vapors indicates that variation of the P:C molar ratio in the composite material affords product slates of varying complexity and composition, which is indicated by the number of products and their relative proportions in the product slate. Our results demonstrate that targeted vapor product composition can be obtained, which can potentially be utilized to tune the composition of the bio-oil downstream.« less

Lattice Matched Carbide–Phosphide Composites with Superior Electrocatalytic Activity and Stability

DOE PAGES

Regmi, Yagya N.; Roy, Asa; King, Laurie A.; ...

2017-10-19

Composites of electrocatalytically active transition-metal compounds present an intriguing opportunity toward enhanced activity and stability. Here, to identify potentially scalable pairs of a catalytically active family of compounds, we demonstrate that phosphides of iron, nickel, and cobalt can be deposited on molybdenum carbide to generate nanocrystalline heterostructures. Composites synthesized via solvothermal decomposition of metal acetylacetonate salts in the presence of highly dispersed carbide nanoparticles show hydrogen evolution activities comparable to those of state-of-the-art non-noble metal catalysts. Investigation of the spent catalyst using high resolution microscopy and elemental analysis reveals that formation of carbide–phosphide composite prevents catalyst dissolution in acid electrolyte.more » Lattice mismatch between the two constituent electrocatalysts can be used to rationally improve electrochemical stability. Among the composites of iron, nickel, and cobalt phosphide, iron phosphide displays the lowest degree of lattice mismatch with molybdenum carbide and shows optimal electrochemical stability. Turnover rates of the composites are higher than that of the carbide substrate and compare favorably to other electrocatalysts based on earth-abundant elements. Lastly, our findings will inspire further investigation into composite nanocrystalline electrocatalysts that use molybdenum carbide as a stable catalyst support.« less

Scalable and Tunable Carbide-Phosphide Composite Catalyst System for the Thermochemical Conversion of Biomass

DOE PAGES

Regmi, Yagya; Rogers, Bridget; Labbe, Nicole; ...

2017-07-13

We have prepared composite materials of hexagonal nickel phosphide and molybdenum carbide (Mo2C) utilizing a simple and scalable two-stage synthesis method comprised of carbothermic reduction followed by hydrothermal incubation. We observe the monophasic hexagonal phosphide Ni2P in the composite at low phosphide-to-carbide (P:C) ratios. Upon increasing the proportion of P:C, the carbide surface becomes saturated, and we detect the emergence of a second hexagonal nickel phosphide phase (Ni5P4) upon annealing. We demonstrate that vapor-phase upgrading (VPU) of whole biomass via catalytic fast pyrolysis is achievable using the composite material as a catalyst, and we monitor the resulting product slates usingmore » pyrolysis gas chromatography/mass spectrometry. Our analysis of the product vapors indicates that variation of the P:C molar ratio in the composite material affords product slates of varying complexity and composition, which is indicated by the number of products and their relative proportions in the product slate. Our results demonstrate that targeted vapor product composition can be obtained, which can potentially be utilized to tune the composition of the bio-oil downstream.« less

Growth and Performance of GaInP/A1GaInP Visible Light Emitting Laser-Diodes,

DTIC Science & Technology

SEMICONDUCTOR LASERS, *EPITAXIAL GROWTH, ALLOYS, LAYERS, LOW PRESSURE, PRESSURE, QUALITY, ROOM TEMPERATURE, SUBSTRATES, GALLIUM PHOSPHIDES, INDIUM PHOSPHIDES, THERMAL PROPERTIES, ENERGY GAPS, ENERGY BANDS, VAPOR PHASES.

New reactions involving the oxidative O-, N-, and C-phosphorylation of organic compounds by phosphorus and phosphides in the presence of metal complexes

NASA Astrophysics Data System (ADS)

Dorfman, Ya A.; Aleshkova, M. M.; Polimbetova, G. S.; Levina, L. V.; Petrova, T. V.; Abdreimova, R. R.; Doroshkevich, D. M.

1993-09-01

The mechanisms of new catalytic reactions leading to the formation of di-, and tri-alkyl phosphates, di- and tri-alkyl phosphites, phosphoramidites, phosphazenes, phosphines, and phosphine oxides from hydrogen, copper, and zinc phosphides and white and red phosphorus are analysed. The mechanisms of the activation of the reactants by metal complexes and of the reactions involving the oxidative P-O, P-N, and P-C coupling of organic compounds to phosphorus and phosphides are considered. The bibliography includes 124 references.

Low Pressure Synthesis of Indium Phosphide,

DTIC Science & Technology

1982-04-01

UNCLASSIFIED F/G 713 M EEEEEEEEEII MEEMMMME W , 2~ h IW 𔃼 * ).I 2 MICROCOP RESOWI1OW TWS CHAT . . WROmNA RUIEJ MT STHDMS-W3-ALORMO TNDM- m &6.4. MM RO - TMS...pNode . M-V Semiconductor compound ’S.T o a.ek* !cm .. EImd’b lc a ..... . P Pocry sline large g rain .bgot of indiumn phosphide have been synthe- simed...indium temperature of 1003"C. 2. BACKGROUND .r. Indium phosphide is a compound composed of elements from the third and fifth columns of the periodic

Thermal Properties and Phonon Spectral Characterization of Synthetic Boron Phosphide for High Thermal Conductivity Applications.

PubMed

Kang, Joon Sang; Wu, Huan; Hu, Yongjie

2017-12-13

Heat dissipation is an increasingly critical technological challenge in modern electronics and photonics as devices continue to shrink to the nanoscale. To address this challenge, high thermal conductivity materials that can efficiently dissipate heat from hot spots and improve device performance are urgently needed. Boron phosphide is a unique high thermal conductivity and refractory material with exceptional chemical inertness, hardness, and high thermal stability, which holds high promises for many practical applications. So far, however, challenges with boron phosphide synthesis and characterization have hampered the understanding of its fundamental properties and potential applications. Here, we describe a systematic thermal transport study based on a synergistic synthesis-experimental-modeling approach: we have chemically synthesized high-quality boron phosphide single crystals and measured their thermal conductivity as a record-high 460 W/mK at room temperature. Through nanoscale ballistic transport, we have, for the first time, mapped the phonon spectra of boron phosphide and experimentally measured its phonon mean free-path spectra with consideration of both natural and isotope-pure abundances. We have also measured the temperature- and size-dependent thermal conductivity and performed corresponding calculations by solving the three-dimensional and spectral-dependent phonon Boltzmann transport equation using the variance-reduced Monte Carlo method. The experimental results are in good agreement with that predicted by multiscale simulations and density functional theory, which together quantify the heat conduction through the phonon mode dependent scattering process. Our finding underscores the promise of boron phosphide as a high thermal conductivity material for a wide range of applications, including thermal management and energy regulation, and provides a detailed, microscopic-level understanding of the phonon spectra and thermal transport mechanisms of boron phosphide. The present study paves the way toward the establishment of a new framework, based on the phonon spectra-material structure relationship, for the rational design of high thermal conductivity materials and nano- to multiscale devices.

Aluminum phosphide

Integrated Risk Information System (IRIS)

Aluminum phosphide ; CASRN 20859 - 73 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

Indium phosphide nanowires and their applications in optoelectronic devices.

PubMed

Zafar, Fateen; Iqbal, Azhar

2016-03-01

Group IIIA phosphide nanocrystalline semiconductors are of great interest among the important inorganic materials because of their large direct band gaps and fundamental physical properties. Their physical properties are exploited for various potential applications in high-speed digital circuits, microwave and optoelectronic devices. Compared to II-VI and I-VII semiconductors, the IIIA phosphides have a high degree of covalent bonding, a less ionic character and larger exciton diameters. In the present review, the work done on synthesis of III-V indium phosphide (InP) nanowires (NWs) using vapour- and solution-phase approaches has been discussed. Doping and core-shell structure formation of InP NWs and their sensitization using higher band gap semiconductor quantum dots is also reported. In the later section of this review, InP NW-polymer hybrid material is highlighted in view of its application as photodiodes. Lastly, a summary and several different perspectives on the use of InP NWs are discussed.

Concept Definition for the Pest Management Component of the Pollution Abatement Management System (PAMS).

DTIC Science & Technology

1982-01-01

able to obtain * Aluminum phosphide, Bromacil, Carbaryl (Sevin), Chlordane, Chlorpyrifos (Oursban), Diazinon, Dichlorovos (DODYP), Malathion, Paraquat...Pentachloro- phenol (PCP), Propoxur (Baygon), Thiram, strychnine/strychnine sulfate, zinc phosphide, and 2,4-D. 10 sufficient data to respond to

Visible light electroluminescent diodes of indium-gallium phosphide

NASA Technical Reports Server (NTRS)

Clough, R.; Richman, D.; Tietjen, J.

1970-01-01

Vapor deposition and acceptor impurity diffusion techniques are used to prepare indium-gallium phosphide junctions. Certain problems in preparation are overcome by altering gas flow conditions and by increasing the concentration of phosphine in the gas. A general formula is given for the alloy's composition.

A case of accidental fatal aluminum phosphide poisoning involving humans and dogs.

PubMed

Behera, Chittaranjan; Krishna, Karthik; Bhardwaj, Daya Nand; Rautji, Ravi; Kumar, Arvind

2015-05-01

Aluminum phosphide is one of the commonest poisons encountered in agricultural areas, and manner of death in the victims is often suicidal and rarely homicidal or accidental. This paper presents an unusual case, where two humans (owner and housemaid) and eight dogs were found dead in the morning hours inside a room of a house, used as shelter for stray dogs. There was allegation by the son of the owner that his father had been killed. Crime scene visit by forensic pathologists helped to collect vital evidence. Autopsies of both the human victims and the dogs were conducted. Toxicological analysis of viscera, vomitus, leftover food, and chemical container at the crime scene tested positive for aluminum phosphide. The cause of death in both humans and dogs was aluminum phosphide poisoning. Investigation by police and the forensic approach to the case helped in ascertaining the manner of death, which was accidental. © 2015 American Academy of Forensic Sciences.

Effect of dislocations on the open-circuit voltage, short-circuit current and efficiency of heteroepitaxial indium phosphide solar cells

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Flood, Dennis J.

1990-01-01

Excellent radiation resistance of indium phosphide solar cells makes them a promising candidate for space power applications, but the present high cost of starting substrates may inhibit their large scale use. Thin film indium phosphide cells grown on Si or GaAs substrates have exhibited low efficiencies, because of the generation and propagation of large number of dislocations. Dislocation densities were calculated and its influence on the open circuit voltage, short circuit current, and efficiency of heteroepitaxial indium phosphide cells was studied using the PC-1D. Dislocations act as predominant recombination centers and are required to be controlled by proper transition layers and improved growth techniques. It is shown that heteroepitaxial grown cells could achieve efficiencies in excess of 18 percent AMO by controlling the number of dislocations. The effect of emitter thickness and surface recombination velocity on the cell performance parameters vs. dislocation density is also studied.

Indium phosphide nanowires and their applications in optoelectronic devices

PubMed Central

Zafar, Fateen

2016-01-01

Group IIIA phosphide nanocrystalline semiconductors are of great interest among the important inorganic materials because of their large direct band gaps and fundamental physical properties. Their physical properties are exploited for various potential applications in high-speed digital circuits, microwave and optoelectronic devices. Compared to II–VI and I–VII semiconductors, the IIIA phosphides have a high degree of covalent bonding, a less ionic character and larger exciton diameters. In the present review, the work done on synthesis of III–V indium phosphide (InP) nanowires (NWs) using vapour- and solution-phase approaches has been discussed. Doping and core–shell structure formation of InP NWs and their sensitization using higher band gap semiconductor quantum dots is also reported. In the later section of this review, InP NW-polymer hybrid material is highlighted in view of its application as photodiodes. Lastly, a summary and several different perspectives on the use of InP NWs are discussed. PMID:27118920

Transition Metal Phosphide Nanoparticles Supported on SBA-15 as Highly Selective Hydrodeoxygenation Catalysts for the Production of Advanced Biofuels.

PubMed

Yang, Yongxing; Ochoa-Hernández, Cristina; de la Peña O'Shea, Víctor A; Pizarro, Patricia; Coronado, Juan M; Serrano, David P

2015-09-01

A series of catalysts constituted by nanoparticles of transition metal (M = Fe, Co, Ni and Mo) phosphides (TMP) dispersed on SBA-15 were synthesized by reduction of the corresponding metal phosphate precursors previously impregnated on the mesostructured support. All the samples contained a metal-loading of 20 wt% and with an initial M/P mole ratio of 1, and they were characterized by X-ray diffraction (XRD), N2 sorption, H2-TPR and transmission electron microscopy (TEM). Metal phosphide nanocatalysts were tested in a high pressure continuous flow reactor for the hydrodeoxygenation (HDO) of a methyl ester blend containing methyl oleate (C17H33-COO-CH3) as main component (70%). This mixture constitutes a convenient surrogate of triglycerides present in vegetable oils, and following catalytic hydrotreating yields mainly n-alkanes. The results of the catalytic assays indicate that Ni2P/SBA-15 catalyst presents the highest ester conversion, whereas the transformation rate is about 20% lower for MoP/SBA-15. In contrast, catalysts based on Fe and Co phosphides show a rather limited activity. Hydrocarbon distribution in the liquid product suggests that both hydrodeoxygenation and decarboxylation/decarbonylation reactions occur simultaneously over the different catalysts, although MoP/SBA-15 possess a selectivity towards hydrodeoxygenation exceeding 90%. Accordingly, the catalyst based on MoP affords the highest yield of n-octadecane, which is the preferred product in terms of carbon atom economy. Subsequently, in order to conjugate the advantages of both Ni and Mo phosphides, a series of catalysts containing variable proportions of both metals were prepared. The obtained results reveal that the mixed phosphides catalysts present a catalytic behavior intermediate between those of the monometallic phosphides. Accordingly, only marginal enhancement of the yield of n-octadecane is obtained for the catalysts with a Mo/Ni ratio of 3. Nevertheless, owing to this high selectivity for hydrodeoxygenation MoP/SBA-15 appears as a very promising catalyst for the production of advanced biofuels.

Strained quantum well photovoltaic energy converter

NASA Technical Reports Server (NTRS)

Freundlich, Alexandre (Inventor); Renaud, Philippe (Inventor); Vilela, Mauro Francisco (Inventor); Bensaoula, Abdelhak (Inventor)

1998-01-01

An indium phosphide photovoltaic cell is provided where one or more quantum wells are introduced between the conventional p-conductivity and n-conductivity indium phosphide layer. The approach allows the cell to convert the light over a wider range of wavelengths than a conventional single junction cell and in particular convert efficiently transparency losses of the indium phosphide conventional cell. The approach hence may be used to increase the cell current output. A method of fabrication of photovoltaic devices is provided where ternary InAsP and InGaAs alloys are used as well material in the quantum well region and results in an increase of the cell current output.

Synthesis and Hydrodeoxygenation Properties of Ruthenium Phosphide Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowker, Richard H.; Smith, Mica C.; Pease, Melissa

2011-07-01

Ru2P/SiO2 and RuP/SiO2 catalysts were prepared by the temperature-programmed reduction (TPR) of uncalcined precursors containing hypophosphite ion (H2PO2-) as the phosphorus source. The Ru2P/SiO2 and RuP/SiO2 catalysts had small average particle sizes (~4 nm) and high CO chemisorption capacities (90-110 umol/g). The Ru phosphide catalysts exhibited similar or higher furan (C4H4O) hydrodeoxygenation (HDO) activities than did a Ru/SiO2 catalyst, and the phosphide catalysts favored C4 hydrocarbon products while the Ru metal catalyst produced primarily C3 hydrocarbons.

Sinterless Fabrication Of Contact Pads On InP Devices

NASA Technical Reports Server (NTRS)

Weizer, Victor G.; Fatemi, Navid S.; Korenyi-Both, Andras L.

1995-01-01

Research has shown that with proper choice of material, low-resistance contact pads deposited on solar cells and other devices by improved technique that does not involve sintering. Research directed at understanding mechanisms involved in contact-sintering process has resulted in identification of special group of materials that includes phosphides of gold, silver, and nickel; specifically, Au(2)P(3), AgP(2), and Ni(3)P. Incorporation of phosphide interlayer substantially reduces resistivity between gold current-carrying layer and indium phosphide substrate. Further research indicated only very thin interlayer of any of these compounds needed to obtain low contact resistance, without subjecting contact to destructive sintering process.

Susan Habas | NREL

Science.gov Websites

chemical transformations Scalable methods for solution-phase nanomaterials synthesis Production of premium Patents "Metal Phosphide Catalysts and Methods for Making the Same and Uses Thereof," U.S . Patent No. 9,636,664 B1 (2017) "Metal Phosphide Catalysts and Methods for Making the Same and Uses

Black-tailed prairie dog populations one year after treatment with rodenticides

Treesearch

Anthony D. Apa; Daniel W. Uresk; Raymond L. Linder

1990-01-01

Three rodenticide treatments, zinc phosphide with prebait, strychnine with prebait, and strychnine without prebait, were applied to black-tailed prairie dog (Cynomys ludovicianus) colonies in west central South Dakota. Results were compared immediately posttreatment and for one year after application. Zinc phosphide was the most effective for...

Development of gallium aluminum phosphide electroluminescent diodes

NASA Technical Reports Server (NTRS)

Chicotka, R. J.; Lorenz, M. R.; Nethercot, A. H.; Pettit, G. D.

1972-01-01

Work done on the development of gallium aluminum phosphide alloys for electroluminescent light sources is described. The preparation of this wide band gap semiconductor alloy, its physical properties (particularly the band structure, the electrical characteristics, and the light emitting properties) and work done on the fabrication of diode structures from these alloys are broadly covered.

Fabrication of hierarchical CoP nanosheet@microwire arrays via space-confined phosphidation toward high-efficiency water oxidation electrocatalysis under alkaline conditions.

PubMed

Ji, Xuqiang; Zhang, Rong; Shi, Xifeng; Asiri, Abdullah M; Zheng, Baozhan; Sun, Xuping

2018-05-03

In spite of recent advances in the synthesis of transition metal phosphide nanostructures, the simple fabrication of hierarchical arrays with more accessible active sites still remains a great challenge. In this Communication, we report a space-confined phosphidation strategy toward developing hierarchical CoP nanosheet@microwire arrays on nickel foam (CoP NS@MW/NF) using a Co(H2PO4)2·2H3PO4 microwire array as the precursor. The thermally stable nature of the anion in the precursor is key to hierarchical nanostructure formation. When used as a 3D electrode for water oxidation electrocatalysis, such CoP NS@MW/NF needs an overpotential as low as 296 mV to drive a geometrical catalytic current density of 100 mA cm-2 in 1.0 M KOH, outperforming all reported Co phosphide catalysts in alkaline media. This catalyst also shows superior long-term electrochemical durability, maintaining its activity for at least 65 h. This study offers us a general method for facile preparation of hierarchical arrays for applications.

Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function.

PubMed

Adolfsson, Karl; Schneider, Martina; Hammarin, Greger; Häcker, Udo; Prinz, Christelle N

2013-07-19

Engineered nanoparticles have been under increasing scrutiny in recent years. High aspect ratio nanoparticles such as carbon nanotubes and nanowires have raised safety concerns due to their geometrical similarity to asbestos fibers. III-V epitaxial semiconductor nanowires are expected to be utilized in devices such as LEDs and solar cells and will thus be available to the public. In addition, clean-room staff fabricating and characterizing the nanowires are at risk of exposure, emphasizing the importance of investigating their possible toxicity. Here we investigated the effects of gallium phosphide nanowires on the fruit fly Drosophila melanogaster. Drosophila larvae and/or adults were exposed to gallium phosphide nanowires by ingestion with food. The toxicity and tissue interaction of the nanowires was evaluated by investigating tissue distribution, activation of immune response, genome-wide gene expression, life span, fecundity and somatic mutation rates. Our results show that gallium phosphide nanowires applied through the diet are not taken up into Drosophila tissues, do not elicit a measurable immune response or changes in genome-wide gene expression and do not significantly affect life span or somatic mutation rate.

Highly efficient photocatalytic H2 evolution using TiO2 nanoparticles integrated with electrocatalytic metal phosphides as cocatalysts

NASA Astrophysics Data System (ADS)

Song, Rui; Zhou, Wu; Luo, Bing; Jing, Dengwei

2017-09-01

In this work, electrocatalysts like the metal phosphides Ni2P, NiCoP, and FeP, can serve as cocatalysts of TiO2 to form efficient composite photocatalysts for hydrogen generation from an aqueous methanol solution. On comparing Ni2P, NiCoP, and FeP and optimizing their proportions, the NiCoP(1 wt%)/TiO2 composite was found to exhibit the highest activity toward photocatalytic H2 production (1.54 μmol h-1 mg-1), which is about thirteen times that of the naked TiO2 nanoparticles. Mott-Schottky (MS) analysis indicated that the large upward shift or band bending of the Fermi energy level (EF) in metal phosphides was responsible for the enhanced activity of the composites. The steady-state photoluminescence (PL) spectra and photocurrent transient response further confirmed that the enhanced photoinduced charge transfer and band separation after TiO2 was integrated with the metal phosphides. Thus, these electrocatalysts were shown to be efficient cocatalysts that can replace noble metals as low-cost photocatalytic H2 production.

Ingestion of gallium phosphide nanowires has no adverse effect on Drosophila tissue function

NASA Astrophysics Data System (ADS)

Adolfsson, Karl; Schneider, Martina; Hammarin, Greger; Häcker, Udo; Prinz, Christelle N.

2013-07-01

Engineered nanoparticles have been under increasing scrutiny in recent years. High aspect ratio nanoparticles such as carbon nanotubes and nanowires have raised safety concerns due to their geometrical similarity to asbestos fibers. III-V epitaxial semiconductor nanowires are expected to be utilized in devices such as LEDs and solar cells and will thus be available to the public. In addition, clean-room staff fabricating and characterizing the nanowires are at risk of exposure, emphasizing the importance of investigating their possible toxicity. Here we investigated the effects of gallium phosphide nanowires on the fruit fly Drosophila melanogaster. Drosophila larvae and/or adults were exposed to gallium phosphide nanowires by ingestion with food. The toxicity and tissue interaction of the nanowires was evaluated by investigating tissue distribution, activation of immune response, genome-wide gene expression, life span, fecundity and somatic mutation rates. Our results show that gallium phosphide nanowires applied through the diet are not taken up into Drosophila tissues, do not elicit a measurable immune response or changes in genome-wide gene expression and do not significantly affect life span or somatic mutation rate.

Mechanism of hydrodenitrogenation on phosphides and sulfides.

PubMed

Oyama, S Ted; Lee, Yong-Kul

2005-02-17

The mechanism of hydrodenitrogenation (HDN) of 2-methylpiperidine was studied over a silica-supported nickel phosphide catalyst (Ni2P/SiO2, Ni/P = 1/2) and a commercial Ni-Mo-S/Al2O3 catalyst in a three-phase trickle-bed reactor operated at 3.1 MPa and 450-600 K. Analysis of the product distribution as a function of contact time indicated that the reaction proceeded in both cases predominantly by a substitution mechanism, with a smaller contribution of an elimination mechanism. Fourier transform infrared spectroscopy (FTIR) of the 2-methylpiperidine indicated that at reaction conditions a piperidinium ion intermediate was formed on both the sulfide and the phosphide. It is concluded that the mechanism of HDN on nickel phosphide is very similar to that on sulfides. The mechanism on the nickel phosphide was also probed by comparing the reactivity of piperidine and several of its derivatives in the presence of 3000 ppm S. The relative elimination rates depended on the structure of the molecules, and followed the sequence: 4-methylpiperidine approximately piperidine > 3-methylpiperidine > 2,6-dimethylpiperidine > 2-methylpiperidine. [Chemical structure: see text] This order of reactivity was not dependent on the number of alpha-H or beta-H atoms in the molecules, ruling out their reaction through a single, simple mechanism. It is likely that the unhindered piperidine molecules reacted by an S(N)2 substitution process and the more hindered 2,6-dimethylpiperidine reacted by an E2 elimination process.

Gap/silicon Tandem Solar Cell with Extended Temperature Range

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A. (Inventor)

2006-01-01

A two-junction solar cell has a bottom solar cell junction of crystalline silicon, and a top solar cell junction of gallium phosphide. A three (or more) junction solar cell has bottom solar cell junctions of silicon, and a top solar cell junction of gallium phosphide. The resulting solar cells exhibit improved extended temperature operation.

Wavelength-scale Microlasers based on VCSEL-Photonic Crystal Architecture

DTIC Science & Technology

2015-01-20

molecular beam epitaxy , MBE). We will also assume the triangular lattice of air...Abbreviations, and Acronyms InP: indium phosphide InGaAsP: indium gallium arsenide phosphide MBE: molecular beam epiitaxy VCSEL : vertical cavity...substrates and were grown by MBE. Electron beam lithography and reactive ion etching was used to deep‐etch the holes of the PhC‐ VCSELS ,

Orientation of Zn3P2 films via phosphidation of Zn precursors

NASA Astrophysics Data System (ADS)

Katsube, Ryoji; Nose, Yoshitaro

2017-02-01

Orientation of solar absorber is an important factor to achieve high efficiency of thin film solar cells. In the case of Zn3P2 which is a promising absorber of low-cost and high-efficiency solar cells, (110)/(001) orientation was only reported in previous studies. We have successfully prepared (101)-oriented Zn3P2 films by phosphidation of (0001)-oriented Zn films at 350 °C. The phosphidation mechanism of Zn is discussed through STEM observations on the partially-reacted sample and the consideration of the relationship between the crystal structures of Zn and Zn3P2 . We revealed that (0001)-oriented Zn led to nucleation of (101)-oriented Zn3P2 due to the similarity in atomic arrangement between Zn and Zn3P2 . The electrical resistivity of the (101)-oriented Zn3P2 film was lower than those of (110)/(001)-oriented films, which is an advantage of the phosphidation technique to the growth processes in previous works. The results in this study demonstrated that well-conductive Zn3P2 films could be obtained by controlling orientations of crystal grains, and provide a guiding principle for microstructure control in absorber materials.

Hydrodeoxygenation of phenolic compounds to cycloalkanes over supported nickel phosphides

DOE PAGES

Yu, Zhiquan; Wang, Anjie; Liu, Shan; ...

2018-05-07

SiO 2, HZSM-5 and Al 2O 3 were used to support nickel phosphides to prepare hydrodeoxygenation (HDO) catalysts. The nickel loading was kept at 20 wt% while the Ni/P molar ratio was varied among 3, 2, and 1 in the preparation by incipient wetness impregnation. XRD characterization revealed that Ni 3P, Ni 12P 5, and Ni 2P as the major crystal phases were obtained at Ni/P ratio of 3, 2, and 1, respectively, on SiO 2 and HZSM-5. When Al 2O 3 was used as the support, nickel metal rather than nickel phosphides was generated. Among SiO 2-supported nickel phosphides,more » Ni 3P exhibited highest hydrogenation activity and catalytic performance in phenol HDO. Ni 3P/HZSM-5 showed the high catalytic performance in HDO of phenol as well as catechol and o-cresol, with Ni 3P as the hydrogenation site and the acid sites in HZSM-5 zeolite as the dehydration site. In conclusion, the strong acidity in HZSM-5 also facilitated the isomerization of cycloalkanes at elevated temperatures.« less

Metal phosphide catalysts and methods for making the same and uses thereof

DOEpatents

Habas, Susan Ellen; Wang, Jun; Ruddy, Daniel A.; Baddour, Frederick Raymond Gabriel; Schaidle, Joshua

2017-05-02

The present disclosure relates to a method that includes heating a mixture that includes a metal phenylphosphine-containing precursor that includes at least one of Mo(PPh.sub.3).sub.2(CO).sub.4, Pd(PPh.sub.3).sub.4, Ru(PPh.sub.3).sub.3Cl.sub.2, Ru(PPh.sub.3).sub.2(CO).sub.2Cl.sub.2, Co(PPh.sub.3)(CO).sub.2(NO), and/or Rh(PPh.sub.3).sub.2(CO)Cl, a surfactant, and a solvent. The heating is to a target temperature to form a heated mixture containing a metal phosphide nanoparticle that includes at least one of MoP, Ru.sub.2P, Co.sub.2P, Rh.sub.2P, and/or Pd.sub.3P, and the metal phosphide nanoparticle is not hollow.

The Mechanism of Anaerobic (Microbial) Corrosion.

DTIC Science & Technology

1982-12-01

hydrogen sulfide reacts with hypophosphite (as well as phosphate and phosphite ) .to form, in the presence of mild steel, iron phosphide, simulating the...of phosphate and phosphite , but not hypophosphite, were observed to have become yellow in 24 hours. The yellow color disap- peared upon exposure to... product is an amorphous type of iron phosphide which can be !- detected b the formation of phos hine upon its acidification. Phosphine( in M IFO, 1473

Efficient water reduction with gallium phosphide nanowires

PubMed Central

Standing, Anthony; Assali, Simone; Gao, Lu; Verheijen, Marcel A.; van Dam, Dick; Cui, Yingchao; Notten, Peter H. L.; Haverkort, Jos E. M.; Bakkers, Erik P. A. M.

2015-01-01

Photoelectrochemical hydrogen production from solar energy and water offers a clean and sustainable fuel option for the future. Planar III/V material systems have shown the highest efficiencies, but are expensive. By moving to the nanowire regime the demand on material quantity is reduced, and new materials can be uncovered, such as wurtzite gallium phosphide, featuring a direct bandgap. This is one of the few materials combining large solar light absorption and (close to) ideal band-edge positions for full water splitting. Here we report the photoelectrochemical reduction of water, on a p-type wurtzite gallium phosphide nanowire photocathode. By modifying geometry to reduce electrical resistance and enhance optical absorption, and modifying the surface with a multistep platinum deposition, high current densities and open circuit potentials were achieved. Our results demonstrate the capabilities of this material, even when used in such low quantities, as in nanowires. PMID:26183949

Status of indium phosphide solar cell development at Spire

NASA Technical Reports Server (NTRS)

Spitzer, M. B.; Keavney, C. J.; Vernon, S. M.

1987-01-01

On-going development of indium phosphide solar cells for space applications is presented. The development is being carried out with a view towards both high conversion efficiency and simplicity of manufacture. The cell designs comprise the ion-implanted cell, the indium tin oxide top contact cell, and the epitaxial cell grown by metal organic chemical vapor deposition. Modelling data on the limit to the efficiency are presented and comparison is made to measured performance data.

Gallium phosphide energy converters

NASA Technical Reports Server (NTRS)

Sims, P. E.; DiNetta, Louis C.; DuganCavanagh, K.; Goetz, M. A.

1996-01-01

Betavoltaic power supplies based on gallium phosphide can supply long term low-level power with high reliability. Results are presented for GaP devices powered by Ni-63 and tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/cm(exp 2) have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. A small demonstration system has been assembled that generates and stores enough electricity to light up an LED.

Aqueous corrosion of phosphide minerals from iron meteorites: a highly reactive source of prebiotic phosphorus on the surface of the early Earth.

PubMed

Pasek, Matthew A; Lauretta, Dante S

2005-08-01

We present the results of an experimental study of aqueous corrosion of Fe-phosphide under conditions relevant to the early Earth. The results strongly suggest that iron meteorites were an important source of reactive phosphorus (P), a requirement for the formation of P-based life. We further demonstrate that iron meteorites were an abundant source of phosphide minerals early in Earth history. Phosphide corrosion was studied in five different solutions: deionized water, deionized water buffered with sodium bicarbonate, deionized water with dissolved magnesium and calcium chlorides, deionized water containing ethanol and acetic acid, and deionized water containing the chlorides, ethanol, and acetic acid. Experiments were performed in the presence of both air and pure Ar gas to evaluate the effect of atmospheric chemistry. Phosphide corrosion in deionized water results in a metastable mixture of mixed-valence, P-bearing ions including pyrophosphate and triphosphate, key components for metabolism in modern life. In a pH-buffered solution of NaHCO(3), the condensed and reduced species diphosphonate is an abundant corrosion product. Corrosion in ethanol- and acetic acid-containing solutions yields additional P-bearing organic molecules, including acetyl phosphonate and a cyclic triphosphorus molecule. Phosphonate is a major corrosion product of all experiments and is the only P-bearing molecule that persists in solutions with high concentrations of magnesium and calcium chlorides, which suggests that phosphonate may have been a primitive oceanic source of P. The stability and reactivity of phosphonate and hypophosphite in solution were investigated to elucidate reaction mechanisms and the role of mineral catalysts on P-solution chemistry. Phosphonate oxidation is rapid in the presence of Fe metal but negligible in the presence of magnetite and in the control sample. The rate of hypophosphite oxidation is independent of reaction substrate.

Second harmonic generation in gallium phosphide photonic crystal nanocavities with ultralow continuous wave pump power.

PubMed

Rivoire, Kelley; Lin, Ziliang; Hatami, Fariba; Masselink, W Ted; Vucković, Jelena

2009-12-07

We demonstrate second harmonic generation in photonic crystal nanocavities fabricated in the semiconductor gallium phosphide. We observe second harmonic radiation at 750 nm with input powers of only nanowatts coupled to the cavity and conversion effciency P(out)/P(2)(in,coupled)=430%/W. The large electronic band gap of GaP minimizes absorption loss, allowing effcient conversion. Our results are promising for integrated, low-power light sources and on-chip reduction of input power in other nonlinear processes.

Hot charcoal vomitus in aluminum phosphide poisoning - A case report of internal thermal reaction in aluminum phosphide poisoning and review of literature

PubMed Central

Mirakbari, Seyed Mostafa

2015-01-01

Aluminium phosphide (ALP) poisoning is a commonly encountered poisoning in emergency departments in most developing countries. Many papers have revealed metabolic derangements in this poisoning and also examined contributing factors leading to death, but only few have reported physical damage. Some case reports have described a complication that has been frequently termed ‘ignition’. The exact mechanism of this phenomenon has not been fully elucidated. An exothermic reaction during therapeutic administration of chemicals may contribute to this problem, but the incidence has occurred in the absence of treatment or drug administration. Here, we report a 34-year-old woman with ALP poisoning who presented with hot charcoal vomitus, a sign of internal thermal event, leading to the thermal burning of the patient's face and internal damage resulting in death. We reviewed all reported cases with similar complication to demonstrate varied characteristics of patients and to propose the possible mechanisms leading to this event. PMID:26257417

Fabrication of Single Crystal Gallium Phosphide Thin Films on Glass.

PubMed

Emmer, Hal; Chen, Christopher T; Saive, Rebecca; Friedrich, Dennis; Horie, Yu; Arbabi, Amir; Faraon, Andrei; Atwater, Harry A

2017-07-05

Due to its high refractive index and low absorption coefficient, gallium phosphide is an ideal material for photonic structures targeted at the visible wavelengths. However, these properties are only realized with high quality epitaxial growth, which limits substrate choice and thus possible photonic applications. In this work, we report the fabrication of single crystal gallium phosphide thin films on transparent glass substrates via transfer bonding. GaP thin films on Si (001) and (112) grown by MOCVD are bonded to glass, and then the growth substrate is removed with a XeF 2 vapor etch. The resulting GaP films have surface roughnesses below 1 nm RMS and exhibit room temperature band edge photoluminescence. Magnesium doping yielded p-type films with a carrier density of 1.6 × 10 17  cm -3 that exhibited mobilities as high as 16 cm 2 V -1 s -1 . Due to their unique optical properties, these films hold much promise for use in advanced optical devices.

Fabrication of Single Crystal Gallium Phosphide Thin Films on Glass

DOE PAGES

Emmer, Hal; Chen, Christopher T.; Saive, Rebecca; ...

2017-07-05

Due to its high refractive index and low absorption coefficient, gallium phosphide is an ideal material for photonic structures targeted at the visible wavelengths. However, these properties are only realized with high quality epitaxial growth, which limits substrate choice and thus possible photonic applications. In this work, we report the fabrication of single crystal gallium phosphide thin films on transparent glass substrates via transfer bonding. GaP thin films on Si (001) and (112) grown by MOCVD are bonded to glass, and then the growth substrate is removed with a XeF 2 vapor etch. The resulting GaP films have surface roughnessesmore » below 1 nm RMS and exhibit room temperature band edge photoluminescence. Magnesium doping yielded p-type films with a carrier density of 1.6 × 10 17 cm -3 that exhibited mobilities as high as 16 cm 2V -1s -1. Therefore, due to their unique optical properties, these films hold much promise for use in advanced optical devices.« less

Cobalt phosphide based nanostructures as bifunctional electrocatalysts for low temperature alkaline water splitting

DOE PAGES

Lambert, Timothy N.; Vigil, Julian A.; Christensen, Ben

2016-08-22

Cobalt phosphide based thin films and nanoparticles were prepared by the thermal phosphidation of spinel Co 3O 4 precursor films and nanoparticles, respectively. CoP films were prepared with overall retention of the Co 3O 4 nanoplatelet morphology while the spherical/cubic Co 3O 4 and Ni 0.15Co 2.85O 4 nanoparticles were converted to nanorods or nanoparticles, respectively. The inclusion of nickel in the nanoparticles resulted in a 2.5 fold higher surface area leading to higher gravimetric performance. In each case high surface area structures were obtained with CoP as the primary phase. All materials were found to act as effective bifunctionalmore » electrocatalysts for both the HER and the OER and compared well to commercial precious metal benchmark materials in alkaline electrolyte. As a result, a symmetrical water electrolysis cell prepared from the CoP-based film operated at a low overpotential of 0.41-0.51 V.« less

Fabrication of Single Crystal Gallium Phosphide Thin Films on Glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Emmer, Hal; Chen, Christopher T.; Saive, Rebecca

Due to its high refractive index and low absorption coefficient, gallium phosphide is an ideal material for photonic structures targeted at the visible wavelengths. However, these properties are only realized with high quality epitaxial growth, which limits substrate choice and thus possible photonic applications. In this work, we report the fabrication of single crystal gallium phosphide thin films on transparent glass substrates via transfer bonding. GaP thin films on Si (001) and (112) grown by MOCVD are bonded to glass, and then the growth substrate is removed with a XeF 2 vapor etch. The resulting GaP films have surface roughnessesmore » below 1 nm RMS and exhibit room temperature band edge photoluminescence. Magnesium doping yielded p-type films with a carrier density of 1.6 × 10 17 cm -3 that exhibited mobilities as high as 16 cm 2V -1s -1. Therefore, due to their unique optical properties, these films hold much promise for use in advanced optical devices.« less

Recent developments in indium phosphide space solar cell research

NASA Technical Reports Server (NTRS)

Brinker, David J.; Weinberg, Irving

1987-01-01

Recent developments and progress in indium phosphide solar cell research for space application are reviewed. Indium phosphide homojunction cells were fabricated in both the n+p and p+n configurations with total area efficiencies of 17.9 and 15.9% (air mass 0 and 25 C) respectively. Organometallic chemical vapor deposition, liquid phase epitaxy, ion implantation and diffusion techniques were employed in InP cell fabrication. A theoretical model of a radiation tolerant, high efficiency homojunction cell was developed. A realistically attainable AMO efficiency of 20.5% was calculated using this model with emitter and base doping of 6 x 10 to the 17th power and 5 x 10 the the 16th power/cu cm respectively. Cells of both configurations were irradiated with 1 MeV electrons and 37 MeV protons. For both proton and electron irradiation, the n+p cells are more radiation resistant at higher fluences than the p+n cells. The first flight module of four InP cells was assembled for the Living Plume Shield III satellite.

In-depth survey report of Early and Daniel Co. , Inc. , Louisville, Kentucky

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaebst, D.D.

1986-09-01

An in-depth industrial hygiene survey was conducted to evaluate worker exposures to phosphine during fumigation of grain at the Early and Daniel Co. grain elevator in Louisville, Kentucky. Stored grain was fumigated using aluminum phosphide. Aluminum-phosphide pellets were also added directly to the grain by the blender as it was poured into the storage containers. Local exhaust ventilation was used at points in the grain-moving system where grain dust was generated. Air samples were taken during full-shift periods at the breathing zone of the weighmaster, two bin floormen, and the blender. Area monitoring samples were also taken. If the operatorsmore » spend considerable time in the vicinity of a bin which is being filled with grain, there is a likelihood of far greater exposure levels being noted. According to the author, further studies of the use of phosphide products at other elevators should be conducted to determine the effect of environmental and process parameters on phosphine exposures.« less

Novel elastic, lattice dynamics and thermodynamic properties of metallic single-layer transition metal phosphides: 2H-M 2P (Mo2P, W2P, Nb2P and Ta2P)

NASA Astrophysics Data System (ADS)

Yin, Jiuren; Wu, Bozhao; Wang, Yanggang; Li, Zhimi; Yao, Yuanpeng; Jiang, Yong; Ding, Yanhuai; Xu, Fu; Zhang, Ping

2018-04-01

Recently, there has been a surge of interest in the research of two-dimensional (2D) phosphides due to their unique physical properties and wide applications. Transition metal phosphides 2H-M 2Ps (Mo2P, W2P, Nb2P and Ta2P) show considerable catalytic activity and energy storage potential. However, the electronic structure and mechanical properties of 2D 2H-M 2Ps are still unrevealed. Here, first-principles calculations are employed to investigate the lattice dynamics, elasticity and thermodynamic properties of 2H-M 2Ps. Results show that M 2Ps with lower stiffness exhibit remarkable lateral deformation under unidirectional loads. Due to the largest average Grüneisen parameter, single-layer Nb2P has the strongest anharmonic vibrations, resulting in the highest thermal expansion coefficient. The lattice thermal conductivities of Ta2P, W2P and Nb2P contradict classical theory, which would predict a smaller thermal conductivity due to the much heavier atom mass. Moreover, the calculations also demonstrate that the thermal conductivity of Ta2P is the highest as well as the lowest thermal expansion, owing to its weak anharmonic phonon scattering and the lowest average Grüneisen parameter. The insight provided by this study may be useful for future experimental and theoretical studies concerning 2D transition metal phosphide materials.

Electrocatalytic activity of cobalt phosphide-modified graphite felt toward VO2+/VO2+ redox reaction

NASA Astrophysics Data System (ADS)

Ge, Zhijun; Wang, Ling; He, Zhangxing; Li, Yuehua; Jiang, Yingqiao; Meng, Wei; Dai, Lei

2018-04-01

A novel strategy for improving the electro-catalytic properties of graphite felt (GF) electrode in vanadium redox flow battery (VRFB) is designed by depositing cobalt phosphide (CoP) onto GF surface. The CoP powder is synthesized by direct carbonization of Co-based zeolitic imidazolate framework (ZIF-67) followed by phosphidation. Cyclic voltammetry results confirm that the CoP-modified graphite felt (GF-CoP) electrode has excellent reversibility and electro-catalytic activity to the VO2+/VO2+ cathodic reaction compared with the pristine GF electrode. The cell using GF-CoP electrode shows apparently higher discharge capacity over that based on GF electrode. The cell using GF-CoP electrode has the capacity of 67.2 mA h at 100 mA cm-2, 32.7 mA h larger than that using GF electrode. Compared with cell using GF electrode, the voltage efficiency of the cell based on GF-CoP electrode increases by 5.9% and energy efficiency by 5.4% at a current density of 100 mA cm-2. The cell using GF-CoP electrode can reach 94.31% capacity retention after 50 cycles at a current density of 30 mA cm-2. The results show that the CoP can effectively promote the VO2+/VO2+ redox reaction, implying that metal phosphides are a new kind of potential catalytic materials for VRFB.

Protonation of a lanthanum phosphide-alkyl occurs at the P-La not the C-La bond: isolation of a cationic lanthanum alkyl complex.

PubMed

Izod, Keith; Liddle, Stephen T; Clegg, William

2004-08-07

Protonation of the heteroleptic, cyclometalated lanthanum phosphide complex [((Me3Si)2CH)(C6H4-2-CH2NMe2)P]La(THF)[P(C6H4-2-CH2NMe2)(CH(SiMe3)(SiMe2CH2))] with [Et3NH][BPh4] yields the cationic alkyllanthanum complex [(THF)4La[P(C6H4-2-CH2NMe2)(CH(SiMe3)(SiMe2CH2))

Comparative radiation resistance, temperature dependence and performance of diffused junction indium phosphide solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Ghandhi, S. K.; Borrego, J. M.

1987-01-01

Indium phosphide solar cells whose p-n junctions were processed by the open tube capped diffusion and by the closed tube uncapped diffusion of sulfur into Czochralski-grown p-type substrates are compared. Differences found in radiation resistance were attributed to the effects of increased base dopant concentration. Both sets of cells showed superior radiation resistance to that of gallium arsenide cells, in agreement with previous results. No correlation was, however, found between the open-circuit voltage and the temperature dependence of the maximum power.

Thin film photovoltaic device

DOEpatents

Catalano, Anthony W.; Bhushan, Manjul

1982-01-01

A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids.

Preparation and characterization of a supported system of Ni2P/Ni12P5 nanoparticles and their use as the active phase in chemoselective hydrogenation of acetophenone

NASA Astrophysics Data System (ADS)

Costa, Dolly C.; Soldati, Analía L.; Pecchi, Gina; Bengoa, José Fernando; Marchetti, Sergio Gustavo; Vetere, Virginia

2018-05-01

Ni2P/Ni12P5 nanoparticles were obtained by thermal decomposition of nickel organometallic salt at low temperature. The use of different characterization techniques allowed us to determine that this process produced a mixture of two nickel phosphide phases: Ni2P and Ni12P5. These nickel phosphides nanoparticles, supported on mesoporous silica, showed activity and high selectivity for producing the hydrogenation of the acetophenone carbonyl group to obtain 1-phenylethanol. This is a first report that demonstrates the ability of supported Ni2P/Ni12P5 nanoparticles to produce the chemoselective hydrogenation of acetophenone. We attribute these special catalytic properties to the particular geometry of the Ni–P sites on the surface of the nanoparticles. This is an interesting result because the nickel phosphides have a wide composition range (from Ni3P to NiP3), with different crystallographic structures, therefore we think that different phases could be active and selective to hydrogenate many important molecules with more than one functional group.

Moringa oleifera extract (Lam) attenuates Aluminium phosphide-induced acute cardiac toxicity in rats.

PubMed

Gouda, Ahmed S; El-Nabarawy, Nagla A; Ibrahim, Samah F

2018-01-01

Moringa oleifera extract (Lam) has many antioxidant and protective properties. Objective: to investigate the antioxidant activities of Lam in counteracting the high oxidative stress caused by acute sub-lethal aluminium phosphide (AlP) intoxication in rat heart. These activities will be detected by histopathological examination and some oxidative stress biomarkers. a single sub-lethal dose of Alp (2 mg/kg body weight) was administered orally, and Lam was given orally at a dose (100 mg/kg body weight) one hour after receiving AlP to rats. aluminium phosphide caused significant cardiac histopathological changes with a significant increase in malondialdehyde (MDA); lipid peroxidation marker; and a significant depletion of antioxidant enzymes (catalase and glutathione reductase). However, treatment with Lam protected efficiently the cardiac tissue of intoxicated rats by increasing antioxidants levels with slight decreasing in MDA production compared to untreated group. This study suggested that Moringa oleifera extract could possibly restore the altered cardiac histopathology and some antioxidant power in AlP intoxicated rats, and it could even be used as adjuvant therapy against AlP-induced cardiotoxicity.

MOF-Derived Ultrathin Cobalt Phosphide Nanosheets as Efficient Bifunctional Hydrogen Evolution Reaction and Oxygen Evolution Reaction Electrocatalysts

PubMed Central

Li, Hong; Ke, Fei; Zhu, Junfa

2018-01-01

The development of a highly efficient and stable bifunctional electrocatalyst for water splitting is still a challenging issue in obtaining clean and sustainable chemical fuels. Herein, a novel bifunctional catalyst consisting of 2D transition-metal phosphide nanosheets with abundant reactive sites templated by Co-centered metal−organic framework nanosheets, denoted as CoP-NS/C, has been developed through a facile one-step low-temperature phosphidation process. The as-prepared CoP-NS/C has large specific surface area and ultrathin nanosheets morphology providing rich catalytic active sites. It shows excellent electrocatalytic performances for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in acidic and alkaline media, with the Tafel slopes of 59 and 64 mV/dec and a current density of 10 mA/cm2 at the overpotentials of 140 and 292 mV, respectively, which are remarkably superior to those of CoP/C, CoP particles, and comparable to those of commercial noble-metal catalysts. In addition, the CoP-NS/C also shows good durability after a long-term test. PMID:29414838

Surface-oxidized cobalt phosphide used as high efficient electrocatalyst in activated carbon air-cathode microbial fuel cell

NASA Astrophysics Data System (ADS)

Yang, Tingting; Wang, Zhong; Li, Kexun; Liu, Yi; Liu, Di; Wang, Junjie

2017-09-01

Herein, we report a simplistic method to fabricate the surface-oxidized cobalt phosphide (CoP) nanocrystals (NCs), which is used as electrocatalyst for oxygen reduction reaction (ORR) in microbial fuel cell (MFC) for the first time. The corallite-like CoP NCs are successfully prepared by a hydrothermal reaction following a phosphating treatment in N2 atmosphere. When used as an ORR catalyst, cobalt phosphide shows comparable onset potential, inferior resistance, as well as a small Tafel slope with long-term stability in neutral media. The maximum power density of MFC embellished with 10% CoP reached 1914.4 ± 59.7 mW m-2, which is 108.5% higher than the control. The four-electron pathway, observed by the RDE, plays a crucial role in electrochemical catalytic activity. In addition, material characterizations indicate that the surface oxide layer (CoOx) around the metallic CoP core is important and beneficial for ORR. Accordingly, it can be expected that the as-synthesized CoP will be a promising candidate of the non-precious metal ORR electrocatalysts for electrochemical energy applications.

Characterization of Gallium Indium Phosphide and Progress of Aluminum Gallium Indium Phosphide System Quantum-Well Laser Diode.

PubMed

Hamada, Hiroki

2017-07-28

Highly ordered gallium indium phosphide layers with the low bandgap have been successfully grown on the (100) GaAs substrates, the misorientation toward [01-1] direction, using the low-pressure metal organic chemical vapor deposition method. It is found that the optical properties of the layers are same as those of the disordered ones, essentially different from the ordered ones having two orientations towards [1-11] and [11-1] directions grown on (100) gallium arsenide substrates, which were previously reported. The bandgap at 300 K is 1.791 eV. The value is the smallest ever reported, to our knowledge. The high performance transverse stabilized AlGaInP laser diodes with strain compensated quantum well structure, which is developed in 1992, have been successfully obtained by controlling the misorientation angle and directions of GaAs substrates. The structure is applied to quantum dots laser diodes. This paper also describes the development history of the quantum well and the quantum dots laser diodes, and their future prospects.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Zhiquan; Wang, Anjie; Liu, Shan

SiO 2, HZSM-5 and Al 2O 3 were used to support nickel phosphides to prepare hydrodeoxygenation (HDO) catalysts. The nickel loading was kept at 20 wt% while the Ni/P molar ratio was varied among 3, 2, and 1 in the preparation by incipient wetness impregnation. XRD characterization revealed that Ni 3P, Ni 12P 5, and Ni 2P as the major crystal phases were obtained at Ni/P ratio of 3, 2, and 1, respectively, on SiO 2 and HZSM-5. When Al 2O 3 was used as the support, nickel metal rather than nickel phosphides was generated. Among SiO 2-supported nickel phosphides,more » Ni 3P exhibited highest hydrogenation activity and catalytic performance in phenol HDO. Ni 3P/HZSM-5 showed the high catalytic performance in HDO of phenol as well as catechol and o-cresol, with Ni 3P as the hydrogenation site and the acid sites in HZSM-5 zeolite as the dehydration site. In conclusion, the strong acidity in HZSM-5 also facilitated the isomerization of cycloalkanes at elevated temperatures.« less

Phosphorization boosts the capacitance of mixed metal nanosheet arrays for high performance supercapacitor electrodes.

PubMed

Lan, Yingying; Zhao, Hongyang; Zong, Yan; Li, Xinghua; Sun, Yong; Feng, Juan; Wang, Yan; Zheng, Xinliang; Du, Yaping

2018-05-01

Binary transition metal phosphides hold immense potential as innovative electrode materials for constructing high-performance energy storage devices. Herein, porous binary nickel-cobalt phosphide (NiCoP) nanosheet arrays anchored on nickel foam (NF) were rationally designed as self-supported binder-free electrodes with high supercapacitance performance. Taking the combined advantages of compositional features and array architectures, the nickel foam supported NiCoP nanosheet array (NiCoP@NF) electrode possesses superior electrochemical performance in comparison with Ni-Co LDH@NF and NiCoO2@NF electrodes. The NiCoP@NF electrode shows an ultrahigh specific capacitance of 2143 F g-1 at 1 A g-1 and retained 1615 F g-1 even at 20 A g-1, showing excellent rate performance. Furthermore, a binder-free all-solid-state asymmetric supercapacitor device is designed, which exhibits a high energy density of 27 W h kg-1 at a power density of 647 W kg-1. The hierarchical binary nickel-cobalt phosphide nanosheet arrays hold great promise as advanced electrode materials for supercapacitors with high electrochemical performance.

Characterization of Gallium Indium Phosphide and Progress of Aluminum Gallium Indium Phosphide System Quantum-Well Laser Diode

PubMed Central

Hamada, Hiroki

2017-01-01

Highly ordered gallium indium phosphide layers with the low bandgap have been successfully grown on the (100) GaAs substrates, the misorientation toward [01−1] direction, using the low-pressure metal organic chemical vapor deposition method. It is found that the optical properties of the layers are same as those of the disordered ones, essentially different from the ordered ones having two orientations towards [1−11] and [11−1] directions grown on (100) gallium arsenide substrates, which were previously reported. The bandgap at 300 K is 1.791 eV. The value is the smallest ever reported, to our knowledge. The high performance transverse stabilized AlGaInP laser diodes with strain compensated quantum well structure, which is developed in 1992, have been successfully obtained by controlling the misorientation angle and directions of GaAs substrates. The structure is applied to quantum dots laser diodes. This paper also describes the development history of the quantum well and the quantum dots laser diodes, and their future prospects. PMID:28773227

Interaction potential for indium phosphide: a molecular dynamics and first-principles study of the elastic constants, generalized stacking fault and surface energies.

PubMed

Branicio, Paulo Sergio; Rino, José Pedro; Gan, Chee Kwan; Tsuzuki, Hélio

2009-03-04

Indium phosphide is investigated using molecular dynamics (MD) simulations and density-functional theory calculations. MD simulations use a proposed effective interaction potential for InP fitted to a selected experimental dataset of properties. The potential consists of two- and three-body terms that represent atomic-size effects, charge-charge, charge-dipole and dipole-dipole interactions as well as covalent bond bending and stretching. Predictions are made for the elastic constants as a function of density and temperature, the generalized stacking fault energy and the low-index surface energies.

Molecular fingerprint-region spectroscopy from 5 to 12  μm using an orientation-patterned gallium phosphide optical parametric oscillator.

PubMed

Maidment, Luke; Schunemann, Peter G; Reid, Derryck T

2016-09-15

We report a femtosecond optical parametric oscillator (OPO) based on the new semiconductor gain material orientation-patterned gallium phosphide (OP-GaP), which enables the production of high-repetition-rate femtosecond pulses spanning 5-12 μm with average powers in the few to tens of milliwatts range. This is the first example of a broadband OPO operating across the molecular fingerprint region, and we demonstrate its potential by conducting broadband Fourier-transform spectroscopy using water vapor and a polystyrene reference standard.

Electronic properties of hexagonal gallium phosphide: A DFT investigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Vipin; Shah, Esha V.; Roy, Debesh R., E-mail: drr@ashd.svnit.ac.in

2016-05-23

A detail density functional investigation is performed to develop hexagonal 2D gallium phosphide material. The geometry, band structure and density of states (total and projected) of 2D hexagonal GaP are reported in detail. It is heartening to note that the developed material is identified as an indirect band gap semiconductor. The indirect gap for this material is predicted as 1.97 eV at K-Γ, and a direct gap of 2.28 eV at K point is achieved, which is very close to the reported direct band gap for zinc blende and buckled structures of GaP.

Thin film photovoltaic device

DOEpatents

Catalano, A.W.; Bhushan, M.

1982-08-03

A thin film photovoltaic solar cell which utilizes a zinc phosphide semiconductor is of the homojunction type comprising an n-type conductivity region forming an electrical junction with a p-type region, both regions consisting essentially of the same semiconductor material. The n-type region is formed by treating zinc phosphide with an extrinsic dopant such as magnesium. The semiconductor is formed on a multilayer substrate which acts as an opaque contact. Various transparent contacts may be used, including a thin metal film of the same chemical composition as the n-type dopant or conductive oxides or metal grids. 5 figs.

Barringerite Fe2P from Pyrometamorphic Rocks of the Hatrurim Formation, Israel

NASA Astrophysics Data System (ADS)

Britvin, S. N.; Murashko, M. N.; Vapnik, E.; Polekhovsky, Yu. S.; Krivovichev, S. V.

2017-12-01

The article provides a detailed mineralogical and crystallochemical description (including refinement of the crystal structure) of the first finding of the phosphide class mineral barringerite, Fe2P, from terrestrial pyrometamorphic rocks of the Hatrurim Formation in Israel. The mineral occurs in the association of the so-called paralavas—initially silicate—carbonate sedimentary rocks that remelted during pyrometamorphic processes at a temperature above 1000°C and at a low pressure. Questions on the genesis and crystal chemistry of barringerite are discussed in connection with another polymorphic iron phosphide, allabogdanite (Fe,Ni)2P.

Low resistance contacts for shallow junction semiconductors

NASA Technical Reports Server (NTRS)

Fatemi, Navid S. (Inventor); Weizer, Victor G. (Inventor)

1994-01-01

A method of enhancing the specific contact resistivity in InP semiconductor devices and improved devices produced thereby are disclosed. Low resistivity values are obtained by using gold ohmic contacts that contain small amounts of gallium or indium and by depositing a thin gold phosphide interlayer between the surface of the InP device and the ohmic contact. When both the thin interlayer and the gold-gallium or gold-indium contact metallizations are used, ultra low specific contact resistivities are achieved. Thermal stability with good contact resistivity is achieved by depositing a layer of refractory metal over the gold phosphide interlayer.

Impact Chemistry and the Origin of Life

NASA Astrophysics Data System (ADS)

Melosh, H. J.; Pasek, M.

2012-12-01

Most discussions of global environmental effects of large impacts focus on changes deleterious to extant life. However, impacts may also produce changes that enhance or even create conditions beneficial to the origin of life. Many other authors have discussed impact delivery of organic molecules, and some have shown the shock synthesis of prebiotic molecules such as amino acids during impact. Our past work on the chemistry of impacts demonstrated that strong chemical reduction occurs in impact melt ejecta (spherules and melt droplets; tektites). Here we focus on the element phosphorus (P), whose role is crucial in biology as the backbone of DNA and RNA, and in metabolic biochemical energy transfer. Pasek previously showed that reduced P readily enters into interesting biological compounds with organic molecules in aqueous solution, and that these reduced P compounds may generate structures similar to sugar phosphates, which are critical to life as we know it. In this talk we argue that impact reduction of P transforms terrestrial and meteoritic phosphates bearing an oxidation state of +5 to the lower redox states of +3 (phosphites) and 0 as an alloy with metal (phosphides). We base this argument on studies of fulgurites—glasses formed by cloud-to-ground lightning—that bear phosphides and phosphites as major carriers of P. Fulgurite chemistry frequently parallels that of impact glasses. Additionally, thermodynamic calculations show that separation of an O-rich vapor from a melt readily results in the transformation of phosphate to phosphites and metal phosphides. These results are confirmed by the presence of metal phosphides within tektites. The impact reduction of phosphates followed by global dispersal of reduced P in the form of glassy droplets likely played a major role in the origin of life on Earth and perhaps on other young planets.

Essential elucidation for preparation of supported nickel phosphide upon nickel phosphate precursor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xuguang, E-mail: liuxuguang@qust.edu.cn; Xu, Lei; Zhang, Baoquan

2014-04-01

Preparation of supported nickel phosphide (Ni{sub 2}P) depends on nickel phosphate precursor, generally related to its chemical composition and supports. Study of this dependence is essential and meaningful for the preparation of supported Ni{sub 2}P with excellent catalytic activity. The chemical nature of nickel phosphate precursor is revealed by Raman and UV–vis spectra. It is found that initial P/Ni mole ratio ≥0.8 prohibits the Ni-O-Ni bridge bonding (i.e., nickel oxide). This chemical bonding will not result in Ni{sub 2}P structure, verified by XRD characterization results. The alumina (namely, γ-Al{sub 2}O{sub 3}, θ-Al{sub 2}O{sub 3}, or α-Al{sub 2}O{sub 3}) with distinctmore » physiochemical properties also results in diverse chemical nature of nickel phosphate, and then different nickel phosphides. The influence of alumina support on producing Ni{sub 2}P was explained by the theory of surface energy heterogeneity, calculated by the NLDFT method based on N{sub 2}-sorption isotherm. The uniform surface energy of α-Al{sub 2}O{sub 3} results only in the nickel phosphosate precursor and thus the Ni{sub 2}P phase. - Graphical abstract: Surface energy heterogeneity in alumina (namely α-Al{sub 2}O{sub 3}, θ-Al{sub 2}O{sub 3}, and γ-Al{sub 2}O{sub 3}) supported multi-oxidic precursors with different reducibilities and thus diverse nickel phosphides (i.e., Ni{sub 3}P, Ni{sub 12}P{sub 5}, Ni{sub 2}P). - Highlights: • Preparing pure Ni{sub 2}P. • Elucidating nickel phosphate precursor. • Associating with surface energy.« less

Diffusion length variation in 0.5- and 3-MeV-proton-irradiated, heteroepitaxial indium phosphide solar cells

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Weinberg, Irving; Flood, Dennis J.

1993-01-01

Indium phosphide (InP) solar cells are more radiation resistant than gallium arsenide (GaAs) and silicon (Si) solar cells, and their growth by heteroepitaxy offers additional advantages leading to the development of light weight, mechanically strong, and cost-effective cells. Changes in heteroepitaxial InP cell efficiency under 0.5- and 3-MeV proton irradiations have been explained by the variation in the minority-carrier diffusion length. The base diffusion length versus proton fluence was calculated by simulating the cell performance. The diffusion length damage coefficient, K(sub L), was also plotted as a function of proton fluence.

A gallium phosphide high-temperature bipolar junction transistor

NASA Technical Reports Server (NTRS)

Zipperian, T. E.; Dawson, L. R.; Chaffin, R. J.

1981-01-01

Preliminary results are reported on the development of a high temperature (350 C) gallium phosphide bipolar junction transistor (BJT) for geothermal and other energy applications. This four-layer p(+)n(-)pp(+) structure was formed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The initial design suffers from a series resistance problem which limits the transistor's usefulness at high temperatures.

Efficient telecom to visible wavelength conversion in doubly resonant gallium phosphide microdisks

NASA Astrophysics Data System (ADS)

Lake, David P.; Mitchell, Matthew; Jayakumar, Harishankar; dos Santos, Laís Fujii; Curic, Davor; Barclay, Paul E.

2016-01-01

Resonant second harmonic generation between 1550 nm and 775 nm with normalized outside efficiency > 3.8 × 10 - 4 mW - 1 is demonstrated in a gallium phosphide microdisk supporting high-Q modes at visible ( Q ˜ 10 4 ) and infrared ( Q ˜ 10 5 ) wavelengths. The double resonance condition is satisfied for a specific pump power through intracavity photothermal temperature tuning using ˜ 360 μ W of 1550 nm light input to a fiber taper and coupled to a microdisk resonance. Power dependent efficiency consistent with a simple model for thermal tuning of the double resonance condition is observed.

Laser ablation synthesis of arsenic-phosphide Asm Pn clusters from As-P mixtures. Laser desorption ionisation with quadrupole ion trap time-of-flight mass spectrometry: The mass spectrometer as a synthesizer.

PubMed

Kubáček, Pavel; Prokeš, Lubomír; Pamreddy, Annapurna; Peña-Méndez, Eladia María; Conde, José Elias; Alberti, Milan; Havel, Josef

2018-05-30

Only a few arsenic phosphides are known. A high potential for the generation of new compounds is offered by Laser Ablation Synthesis (LAS) and when Laser Desorption Ionization (LDI) is coupled with simultaneous Time-Of-Flight Mass Spectrometry (TOFMS), immediate identification of the clusters can be achieved. LAS was used for the generation of arsenic phosphides via laser ablation of phosphorus-arsenic mixtures while quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to acquire the mass spectra. Many new As m P n ± clusters (479 binary and 369 mono-elemental) not yet described in the literature were generated in the gas phase and their stoichiometry determined. The likely structures for some of the observed clusters arbitrary selected (20) were computed by density functional theory (DFT) optimization. LAS is an advantageous approach for the generation of new As m P n clusters, while mass spectrometry was found to be an efficient technique for the determination of cluster stoichiometry. The results achieved might inspire the synthesis of new materials. Copyright © 2018 John Wiley & Sons, Ltd.

Uranium distribution in pseudowollastonite slag from a phosphorus furnace

USGS Publications Warehouse

Young, Edward; Altschuler, Zalman S.

1956-01-01

Silicate slag from the Victor Chemical Company phosphorus furnace at Tarpon Springs, Fla., has been found to consist essentially of pseudowollastonite, α-CaSiO3. The first-formed crystals are euhedral laths which form a mesh making up most of the slag. As the slag continues to solidify, its composition changes slightly and more equant, subhedral crystals of pseudowollastonite are deposited within the framework of the earlier material. Finally, anherdral masses of fibrous, poorly crystallized material are deposited in the remaining pore spaces which are not always completely filled. Spherules of iron phosphide, Fe2P, occur very sparsely in the slag as inclusions from the immiscible iron phosphide melt. Uranium content increases in the later crystal products of the slag, and by heavy-liquid fractionation it has been possible to segregate partially the phases and to obtain a fourfold concentration of uranium in 5 percent of the material and a twofold concentration in 30 percent of the material. Nuclear-emulsion studies indicate that the last phases of the silicate slag are actually eight times as radioactive as the early phases. In addition, the iron phosphide spherules are comparably enriches in uranium.

General One-Pot Synthesis of Transition-Metal Phosphide/Nitrogen-Doped Carbon Hybrid Nanosheets as Ultrastable Anodes for Sodium-Ion Batteries.

PubMed

Li, Jingjing; Shi, Liang; Gao, Jingyu; Zhang, Genqiang

2018-01-26

Sodium-ion batteries (SIBs) have been considered as promising energy storage devices in grid-level applications, owing to their largely reduced cost compared with that of lithium-ion batteries. However, the practical application of SIBs has been seriously hindered because of the lack of appropriate anode materials, limited by the thermodynamics perspective, which is one of the central task at current stage. Herein, we have developed a general one-pot strategy for the synthesis of transition-metal phosphide (TMP) based hybrid nanosheets composed of carbon-coated TMP nanoparticles anchored to the surface of nitrogen-doped carbon nanosheets. This facile and cost-effective method is quite universal and holds potential to be further extended to other metal phosphide materials. Significantly, the hybrid nanosheet electrode possesses excellent sodium storage properties as anodes for SIBs, including high specific capacity, an ultra-long cycle life and a remarkable rate performance. This work makes a significant contribution to not only the synthetic methodology of TMP-carbon two-dimensional hybrid nanostructures, but also the application of TMP-based anodes for high-energy SIBs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

MXP(M = Co/Ni)@carbon core-shell nanoparticles embedded in 3D cross-linked graphene aerogel derived from seaweed biomass for hydrogen evolution reaction.

PubMed

Zhao, Wentong; Lu, Xiaoqing; Selvaraj, Manickam; Wei, Wei; Jiang, Zhifeng; Ullah, Nabi; Liu, Jie; Xie, Jimin

2018-05-24

Low-cost electrocatalysts play an important role in the hydrogen evolution reaction (HER). Particularly, transition metal phosphides (TMPs) are widely applied in the development of HER electrocatalysts. To improve the poor electrochemical reaction kinetics of HER, we introduce a facile way to synthesize carbon core-shell materials containing cobalt phosphide nanoparticles embedded in different graphene aerogels (GAs) (CoP@C-NPs/GA-x (x = 5, 10 and 20)) using seaweed biomass as precursors. The synthesized CoP@C-NPs/GA-5 exhibits efficient catalytic activity with small overpotentials of 120 and 225 mV at current densities of 10 mA cm-2, along with the low Tafel slopes of 57 and 66 mV dec-1, for HER in acidic and alkaline electrolytes, respectively. Compared with carbon aerogel (CA) containing cobalt phosphide nanoparticles (CoP-NPs@CA), the stability of CoP@C-NPs/GA-5 coated with carbon-shells (∼0.8 nm) was significantly improved in acidic electrolytes. We also prepared carbon core-shell materials containing nickel phosphide nanoparticles embedded in GA (Ni2P@C-NPs/GA) to further expand this synthetic route. The graphene-Ni2P@C aerogel shows a similar morphology and better catalytic activity for HER in acidic and alkaline electrolytes. In this work, the robust three-dimensional (3D) GA matrix with abundant open pores and large surface area provides unblocked channels for electrolyte contact and electronic transfer and enables very close contact between the catalyst and electrolyte. The MxP@C core-shell structure prevents the inactivation of MxP NPs during HER processes, and the thin graphene oxide (GO) layers and 3D CA together build up a 3D conductive matrix, which not only adjusts the volume expansion of MxP NPs as well as preventing their aggregation, but also provides a 3D conductive pathway for rapid charge transfer processes. The present synthetic strategy for phosphides via in situ phosphorization with 3D GA can be extended to other novel high-performance catalysts. The simple synthesis and efficient catalytic activity of MXP@C-NPs/GA indicate good application prospects in HER.

The relation of the yield stress of high-pressure anvils to the pressure attained at yielding and the ultimate attainable pressure

NASA Technical Reports Server (NTRS)

Panda, P. C.; Ruoff, A. L.

1979-01-01

A sensitive microprofilometer was used to determine the onset of yielding in the anvils of a supported opposed anvil device for the case of 3% cobalt-cemented tungsten carbide as the anvil material. In addition, it is shown how the commencement of yielding in boron carbide pistons, the yield strength being known, can be used to obtain the transition pressure to a conducting phase in gallium phosphide. The transition pressures of bismuth and gallium phosphide are obtained and it is found that these transitions are extremely close to the maximum attainable pressure in, respectively, a maraging steel and a 3% cobalt-cemented tungsten carbide.

Vapor phase growth technique of III-V compounds utilizing a preheating step

NASA Technical Reports Server (NTRS)

Olsen, Gregory Hammond (Inventor); Zamerowski, Thomas Joseph (Inventor); Buiocchi, Charles Joseph (Inventor)

1978-01-01

In the vapor phase epitaxy fabrication of semiconductor devices and in particular semiconductor lasers, the deposition body on which a particular layer of the laser is to be grown is preheated to a temperature about 40.degree. to 60.degree. C. lower than the temperature at which deposition occurs. It has been discovered that by preheating at this lower temperature there is reduced thermal decomposition at the deposition surface, especially for semiconductor materials such as indium gallium phosphide and gallium arsenide phosphide. A reduction in thermal decomposition reduces imperfections in the deposition body in the vicinity of the deposition surface, thereby providing a device with higher efficiency and longer lifetime.

Effects of Polyethylene Glycol and Citric Acid on Preparation and Hydrodechlorination Activity of Molybdenum Phosphide

NASA Astrophysics Data System (ADS)

Liu, Xiaomeng; Lu, Shaoxiang; Xu, Hanghui; Ren, Lili

2018-07-01

Molybdenum phosphide (MoP), modified by polyethylene glycol (PEG) and citric acid (CA), exhibited 2 to 3 times superior activity than the MoP modified by CA alone. And the optimal activity temperature was reduced from 500 to 450oC. The catalyst was fully characterized by a variety of techniques including X-ray diffraction (XRD), N2 adsorption-desorption isotherm, scanning electron microscopy (SEM), transmission electron microscopy (TEM). The results showed that the addition of PEG and CA increased the surface area of MoP and decreased the particle size of MoP. Furthermore, the reaction mechanism also has been discussed by combining the activity data and characterization results.

Theoretical prediction of sandwiched two-dimensional phosphide binary compound sheets with tunable bandgaps and anisotropic physical properties

NASA Astrophysics Data System (ADS)

Zhang, C. Y.; Yu, M.

2018-03-01

Atomic layers of GaP and InP binary compounds with unique anisotropic structural, electronic and mechanical properties have been predicted from first-principle molecular dynamics simulations. These new members of the phosphide binary compound family stabilize to a sandwiched two-dimensional (2D) crystalline structure with orthorhombic lattice symmetry and high buckling of 2.14 Å-2.46 Å. Their vibration modes are similar to those of phosphorene with six Raman active modes ranging from ˜80 cm-1 to 400 cm-1. The speeds of sound in their phonon dispersions reflect anisotropy in their elastic constants, which was further confirmed by their strong directional dependence of Young’s moduli and effective nonlinear elastic moduli. They show wide bandgap semiconductor behavior with fundamental bandgaps of 2.89 eV for GaP and 2.59 eV for InP, respectively, even wider than their bulk counterparts. Such bandgaps were found to be tunable under strain. In particular, a direct-indirect bandgap transition was found under certain strains along zigzag or biaxial orientations, reflecting their promising applications in strain-induced bandgap engineering in nanoelectronics and photovoltaics. Feasible pathways to realize these novel 2D phosphide compounds are also proposed.

Scalable Indium Phosphide Thin-Film Nanophotonics Platform for Photovoltaic and Photoelectrochemical Devices.

PubMed

Lin, Qingfeng; Sarkar, Debarghya; Lin, Yuanjing; Yeung, Matthew; Blankemeier, Louis; Hazra, Jubin; Wang, Wei; Niu, Shanyuan; Ravichandran, Jayakanth; Fan, Zhiyong; Kapadia, Rehan

2017-05-23

Recent developments in nanophotonics have provided a clear roadmap for improving the efficiency of photonic devices through control over absorption and emission of devices. These advances could prove transformative for a wide variety of devices, such as photovoltaics, photoelectrochemical devices, photodetectors, and light-emitting diodes. However, it is often challenging to physically create the nanophotonic designs required to engineer the optical properties of devices. Here, we present a platform based on crystalline indium phosphide that enables thin-film nanophotonic structures with physical morphologies that are impossible to achieve through conventional state-of-the-art material growth techniques. Here, nanostructured InP thin films have been demonstrated on non-epitaxial alumina inverted nanocone (i-cone) substrates via a low-cost and scalable thin-film vapor-liquid-solid growth technique. In this process, indium films are first evaporated onto the i-cone structures in the desired morphology, followed by a high-temperature step that causes a phase transformation of the indium into indium phosphide, preserving the original morphology of the deposited indium. Through this approach, a wide variety of nanostructured film morphologies are accessible using only control over evaporation process variables. Critically, the as-grown nanotextured InP thin films demonstrate excellent optoelectronic properties, suggesting this platform is promising for future high-performance nanophotonic devices.

Surface Chemistry in Cobalt Phosphide-Stabilized Lithium-Sulfur Batteries.

PubMed

Zhong, Yiren; Yin, Lichang; He, Peng; Liu, Wen; Wu, Zishan; Wang, Hailiang

2018-01-31

Chemistry at the cathode/electrolyte interface plays an important role for lithium-sulfur batteries in which stable cycling of the sulfur cathode requires confinement of the lithium polysulfide intermediates and their fast electrochemical conversion on the electrode surface. While many materials have been found to be effective for confining polysulfides, the underlying chemical interactions remain poorly understood. We report a new and general lithium polysulfide-binding mechanism enabled by surface oxidation layers of transition-metal phosphide and chalcogenide materials. We for the first time find that CoP nanoparticles strongly adsorb polysulfides because their natural oxidation (forming Co-O-P-like species) activates the surface Co sites for binding polysulfides via strong Co-S bonding. With a surface oxidation layer capable of confining polysulfides and an inner core suitable for conducting electrons, the CoP nanoparticles are thus a desirable candidate for stabilizing and improving the performance of sulfur cathodes in lithium-sulfur batteries. We demonstrate that sulfur electrodes that hold a high mass loading of 7 mg cm -2 and a high areal capacity of 5.6 mAh cm -2 can be stably cycled for 200 cycles. We further reveal that this new surface oxidation-induced polysulfide-binding scheme applies to a series of transition-metal phosphide and chalcogenide materials and can explain their stabilizing effects for lithium-sulfur batteries.

Hierarchical cobalt poly-phosphide hollow spheres as highly active and stable electrocatalysts for hydrogen evolution over a wide pH range

NASA Astrophysics Data System (ADS)

Wu, Tianli; Pi, Mingyu; Wang, Xiaodeng; Guo, Weimeng; Zhang, Dingke; Chen, Shijian

2018-01-01

Exploring highly-efficient and low-cost non-noble metal electrocatalyst toward the hydrogen evolution reaction (HER) is highly desired for renewable energy system but remains challenging. In this work, three dimensional hierarchical porous cobalt poly-phosphide hollow spheres (CoP3 HSs) were prepared by topotactic phosphidation of the cobalt-based precursor via vacuum encapsulation technique. As a porous HER cathode, the CoP3 HSs delivers remarkable electrocatalytic performance over the wide pH range. It needs overpotentials of -69 mV and -118 mV with a small Tafel slope of 51 mV dec-1 to obtain current densities of 10 mA cm-2 and 50 mA cm-2, respectively, and maintains its electrocatalytic performance over 30 h in acidic solution. In addition, CoP3 also exhibit superior electrocatalytic performance and stability under neutral and alkaline conditions for the HER. Both experimental measurements and density functional theory (DFT) calculations are performed to explore the mechanism behind the excellent HER performance. The results of our study make the porous CoP3 HSs as a promising electrocatalyst for practical applications toward energy conversion system and present a new way for designing and fabricating HER electrodes through high degree of phosphorization and nano-porous architecture.

Tailored surface structure of LiFePO4/C nanofibers by phosphidation and their electrochemical superiority for lithium rechargeable batteries.

PubMed

Lee, Yoon Cheol; Han, Dong-Wook; Park, Mihui; Jo, Mi Ru; Kang, Seung Ho; Lee, Ju Kyung; Kang, Yong-Mook

2014-06-25

We offer a brand new strategy for enhancing Li ion transport at the surface of LiFePO4/C nanofibers through noble Li ion conducting pathways built along reduced carbon webs by phosphorus. Pristine LiFePO4/C nanofibers composed of 1-dimensional (1D) LiFePO4 nanofibers with thick carbon coating layers on the surfaces of the nanofibers were prepared by the electrospinning technique. These dense and thick carbon layers prevented not only electrolyte penetration into the inner LiFePO4 nanofibers but also facile Li ion transport at the electrode/electrolyte interface. In contrast, the existing strong interactions between the carbon and oxygen atoms on the surface of the pristine LiFePO4/C nanofibers were weakened or partly broken by the adhesion of phosphorus, thereby improving Li ion migration through the thick carbon layers on the surfaces of the LiFePO4 nanofibers. As a result, the phosphidated LiFePO4/C nanofibers have a higher initial discharge capacity and a greatly improved rate capability when compared with pristine LiFePO4/C nanofibers. Our findings of high Li ion transport induced by phosphidation can be widely applied to other carbon-coated electrode materials.

SEM-EDX analysis of an unknown "known" white powder found in a shipping container from Peru

NASA Astrophysics Data System (ADS)

Albright, Douglas C.

2009-05-01

In 2008, an unknown white powder was discovered spilled inside of a shipping container of whole kernel corn during an inspection by federal inspectors in the port of Baltimore, Maryland. The container was detained and quarantined while a sample of the powder was collected and sent to a federal laboratory where it was screened using chromatography for the presence of specific poisons and pesticides with negative results. Samples of the corn kernels and the white powder were forwarded to the Food and Drug Administration, Forensic Chemistry Center for further analysis. Stereoscopic Light Microscopy (SLM), Scanning Electron Microscopy/Energy Dispersive X-ray Spectrometry (SEM/EDX), and Polarized Light Microscopy/Infrared Spectroscopy (PLM-IR) were used in the analysis of the kernels and the unknown powder. Based on the unique particle analysis by SLM and SEM as well as the detection of the presence of aluminum and phosphorous by EDX, the unknown was determined to be consistent with reacted aluminum phosphide (AlP). While commonly known in the agricultural industry, aluminum phosphide is relatively unknown in the forensic community. A history of the use and acute toxicity of this compound along with some very unique SEM/EDX analysis characteristics of aluminum phosphide will be discussed.

Novel tungsten phosphide embedded nitrogen-doped carbon nanotubes: A portable and renewable monitoring platform for anticancer drug in whole blood.

PubMed

Zhou, Haifeng; Ran, Guoxia; Masson, Jean-Francois; Wang, Chan; Zhao, Yuan; Song, Qijun

2018-05-15

Biosensors based on converting the concentration of analytes in complex samples into single electrochemical signals are attractive candidates as low cost, high-throughput, portable and renewable sensor platforms. Here, we describe a simple but practical analytical device for sensing an anticancer drug in whole blood, using the detection of methotrexate (MTX) as a model system. In this biosensor, a novel carbon-based composite, tungsten phosphide embedded nitrogen-doped carbon nanotubes (WP/N-CNT), was fixed to the electrode surface that supported redox cycling. The electronic transmission channel in nitrogen doped carbon nanotubes (N-CNT) and the synergistic effect of uniform distribution tungsten phosphide (WP) ensured that the electrode materials have outstanding electrical conductivity and catalytic performance. Meanwhile, the surface electronic structure also endows its surprisingly reproducible performance. To demonstrate portable operation for MTX sensing, screen printing electrodes (SPE) was modified with WP/N-CNT. The sensor exhibited low detection limits (45 nM), wide detection range (0.01-540 μM), good selectivity and long-term stability for the determination of MTX. In addition, the technique was successfully applied for the determination of MTX in whole blood. Copyright © 2018 Elsevier B.V. All rights reserved.

Clinical characteristics of zinc phosphide poisoning in Thailand.

PubMed

Trakulsrichai, Satariya; Kosanyawat, Natcha; Atiksawedparit, Pongsakorn; Sriapha, Charuwan; Tongpoo, Achara; Udomsubpayakul, Umaporn; Rittilert, Panee; Wananukul, Winai

2017-01-01

The objectives of this study were to describe the clinical characteristics and outcomes of poisoning by zinc phosphide, a common rodenticide in Thailand, and to evaluate whether these outcomes can be prognosticated by the clinical presentation. A 3-year retrospective cohort study was performed using data from the Ramathibodi Poison Center Toxic Exposure Surveillance System. In total, 455 poisonings were identified. Most were males (60.5%) and from the central region of Thailand (71.0%). The mean age was 39.91±19.15 years. The most common route of exposure was oral (99.3%). Most patients showed normal vital signs, oxygen saturation, and consciousness at the first presentation. The three most common clinical presentations were gastrointestinal (GI; 68.8%), cardiovascular (22.0%), and respiratory (13.8%) signs and symptoms. Most patients had normal blood chemistry laboratory results and chest X-ray findings at presentation. The median hospital stay was 2 days, and the mortality rate was 7%. Approximately 70% of patients underwent GI decontamination, including gastric lavage and a single dose of activated charcoal. In all, 31 patients were intubated and required ventilator support. Inotropic drugs were given to 4.2% of patients. Four moribund patients also received hyperinsulinemia-euglycemia therapy and intravenous hydrocortisone; however, all died. Patients who survived and died showed significant differences in age, duration from taking zinc phosphide to hospital presentation, abnormal vital signs at presentation (tachycardia, low blood pressure, and tachypnea), acidosis, hypernatremia, hyperkalemia, in-hospital acute kidney injury, in-hospital hypoglycemia, endotracheal tube intubation, and inotropic requirement during hospitalization ( P <0.05). Zinc phosphide poisoning causes fatalities. Most patients have mild symptoms, and GI symptoms are the most common. Patients who present with abnormal vital signs or electrolytes might have more severe poisoning and should be closely monitored and aggressively treated. All patients should be observed in the hospital for 2 days and followed up for cardiovascular and respiratory symptoms, electrolyte balances, kidney function, and blood glucose.

Pesticide poisoning.

PubMed

Goel, Ashish; Aggarwal, Praveen

2007-01-01

Acute poisoning with pesticides is a global public health problem and accounts for as many as 300,000 deaths worldwide every year. The majority of deaths occur due to exposure to organophosphates, organochlorines and aluminium phosphide. Organophosphate compounds inhibit acetylcholinesterase resulting in acute toxicity. Intermediate syndrome can develop in a number of patients and may lead to respiratory paralysis and death. Management consists of proper oxygenation, atropine in escalating doses and pralidoxime in high doses. It is Important to decontaminate the skin while taking precautions to avoid secondary contamination of health personnel. Organochlorine pesticides are toxic to the central nervous system and sensitize the myocardium to catecholamines. Treatment involves supportive care and avoiding exogenous sympathomimetic agents. Ingestion of paraquat causes severe inflammation of the throat, corrosive injury to the gastrointestinal tract, renal tubular necrosis, hepatic necrosis and pulmonary fibrosis. Administration of oxygen should be avoided as it produces more fibrosis. Use of immunosuppressive agents have improved outcome in patients with paraquat poisoning. Rodenticides include thallium, superwarfarins, barium carbonate and phosphides (aluminium and zinc phosphide). Alopecia is an atypical feature of thallium toxicity. Most exposures to superwarfarins are harmless but prolonged bleeding may occur. Barium carbonate Ingestion can cause severe hypokalaemia and respiratory muscle paralysis. Aluminium phosphide is a highly toxic agent with mortality ranging from 37% to 100%. It inhibits mitochondrial cytochrome c oxidase and leads to pulmonary and cardiac toxicity. Treatment is supportive with some studies suggesting a beneficial effect of magnesium sulphate. Pyrethroids and insect repellants (e.g. diethyltoluamide) are relatively harmless but can cause toxic effects to pulmonary and central nervous systems. Ethylene dibromide-a highly toxic, fumigant pesticide-produces oral ulcerations, followed by liver and renal toxicity, and is almost uniformly fatal. Physicians working in remote and rural areas need to be educated about early diagnosis and proper management using supportive care and antidotes, wherever available.

Thorium Copper Phosphides: More Diverse Metal-Phosphorus and Phosphorus-Phosphorus Interactions than U analogues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Geng Bang; Malliakas, Christos D.; Lin, Jian

To explore the chemical analogy between thorium and heavier actinides in soft anionic environments, three new thorium phosphides (ThCuP 2, beta-ThCu 2P 2, and ThCu 5P 3) have been prepared through solid-state reactions using CuI as a reaction promoter. The structure of ThCuP 2 can be described as a filled UTe 2-type with both dimeric P 2 4- and monomeric P 3- anions, in which Th is coordinated by eight P atoms in a bicapped trigonal prismatic arrangement and Cu is tetrahedrally coordinated by four P atoms. β-ThCu 2P 2 contains only P 3- anions and is isostructural with BaCumore » 2S 2. In this structure, Th is coordinated by seven P atoms in monocapped trigonal prismatic geometry and Cu is tetrahedrally coordinated by four P atoms. ThCu 5P 3 adopts the YCo 5P 3-type structure consisting of P 3- anions. This structure contains Th atoms coordinated by six P atoms in a trigonal prismatic arrangement and Cu atoms that are either tetrahedrally coordinated by four P atoms or square pyramidally coordinated by five P atoms. Electric resistivity measurements and electronic structure calculations on β-ThCu 2P 2 indicate a metal. These new compounds may be charge-balanced and formulated as Th 4+Cu +(P 2 4-) 1/2P 3-, Th 4+(Cu +) 2(P 3-) 2, and Th 4+(Cu +) 5(P 3-) 3, respectively. The structural, bonding, and property relationships between these Th compounds and related actinide and rare-earth phases are discussed. In conclusion, titled compounds display more diverse ion-ion interactions and different electronic structures from those in UCuP 2 and UCu 2P 2 that were synthesized under similar experimental conditions, suggesting divergence of thorium-phosphide chemistry from uranium-phosphide chemistry.« less

Thorium Copper Phosphides: More Diverse Metal-Phosphorus and Phosphorus-Phosphorus Interactions than U analogues

DOE PAGES

Jin, Geng Bang; Malliakas, Christos D.; Lin, Jian

2017-09-28

To explore the chemical analogy between thorium and heavier actinides in soft anionic environments, three new thorium phosphides (ThCuP 2, beta-ThCu 2P 2, and ThCu 5P 3) have been prepared through solid-state reactions using CuI as a reaction promoter. The structure of ThCuP 2 can be described as a filled UTe 2-type with both dimeric P 2 4- and monomeric P 3- anions, in which Th is coordinated by eight P atoms in a bicapped trigonal prismatic arrangement and Cu is tetrahedrally coordinated by four P atoms. β-ThCu 2P 2 contains only P 3- anions and is isostructural with BaCumore » 2S 2. In this structure, Th is coordinated by seven P atoms in monocapped trigonal prismatic geometry and Cu is tetrahedrally coordinated by four P atoms. ThCu 5P 3 adopts the YCo 5P 3-type structure consisting of P 3- anions. This structure contains Th atoms coordinated by six P atoms in a trigonal prismatic arrangement and Cu atoms that are either tetrahedrally coordinated by four P atoms or square pyramidally coordinated by five P atoms. Electric resistivity measurements and electronic structure calculations on β-ThCu 2P 2 indicate a metal. These new compounds may be charge-balanced and formulated as Th 4+Cu +(P 2 4-) 1/2P 3-, Th 4+(Cu +) 2(P 3-) 2, and Th 4+(Cu +) 5(P 3-) 3, respectively. The structural, bonding, and property relationships between these Th compounds and related actinide and rare-earth phases are discussed. In conclusion, titled compounds display more diverse ion-ion interactions and different electronic structures from those in UCuP 2 and UCu 2P 2 that were synthesized under similar experimental conditions, suggesting divergence of thorium-phosphide chemistry from uranium-phosphide chemistry.« less

High-efficiency indium tin oxide/indium phosphide solar cells

NASA Technical Reports Server (NTRS)

Li, X.; Wanlass, M. W.; Gessert, T. A.; Emery, K. A.; Coutts, T. J.

1989-01-01

Improvements in the performance of indium tin oxide (ITO)/indium phosphide solar cells have been realized by the dc magnetron sputter deposition of n-ITO onto an epitaxial p/p(+) structure grown on commercial p(+) bulk substrates. The highest efficiency cells were achieved when the surface of the epilayer was exposed to an Ar/H2 plasma before depositing the bulk of the ITO in a more typical Ar/O2 plasma. With H2 processing, global efficiencies of 18.9 percent were achieved. It is suggested that the excellent performance of these solar cells results from the optimization of the doping, thickness, transport, and surface properties of the p-type base, as well as from better control over the ITO deposition procedure.

Growth of indium gallium arsenide thin film on silicon substrate by MOCVD technique

NASA Astrophysics Data System (ADS)

Chowdhury, Sisir; Das, Anish; Banerji, Pallab

2018-05-01

Indium gallium arsenide (InGaAs) thin film with indium phosphide (InP) buffer has been grown on p-type silicon (100) by Metal Organic Chemical Vapor Deposition (MOCVD) technique. To get a lattice matched substrate an Indium Phosphide buffer thin film is deposited onto Si substrate prior to InGaAs growth. The grown films have been investigated by UV-Vis-NIR reflectance spectroscopy. The band gap energy of the grown InGaAs thin films determined to be 0.82 eV from reflectance spectrum and the films are found to have same thickness for growth between 600 °C and 650 °C. Crystalline quality of the grown films has been studied by grazing incidence X-ray diffractometry (GIXRD).

Properties of GaP Schottky barrier diodes at elevated temperatures.

NASA Technical Reports Server (NTRS)

Nannichi, Y.; Pearson, G. L.

1969-01-01

Gallium phosphide Schottky barrier diodes, discussing construction and metals used, barrier height relationships to impurity concentration and temperature, rectifying characteristics and internal quantum efficiency

Trends in activity for the oxygen evolution reaction on transition metal (M = Fe, Co, Ni) phosphide pre-catalysts† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc05033j

PubMed Central

Xu, Junyuan; Li, Junjie; Xiong, Dehua; Zhang, Bingsen; Liu, Yuefeng; Wu, Kuang-Hsu; Amorim, Isilda; Li, Wei

2018-01-01

Transition metal phosphides (TMPs) have recently emerged as a new class of pre-catalysts that can efficiently catalyze the oxygen evolution reaction (OER). However, how the OER activity of TMPs varies with the catalyst composition has not been systematically explored. Here, we report the alkaline OER electrolysis of a series of nanoparticulate phosphides containing different equimolar metal (M = Fe, Co, Ni) components. Notable trends in OER activity are observed, following the order of FeP < NiP < CoP < FeNiP < FeCoP < CoNiP < FeCoNiP, which indicate that the introduction of a secondary metal(s) to a mono-metallic TMP substantially boosts the OER performance. We ascribe the promotional effect to the enhanced oxidizing power of bi- and tri-metallic TMPs that can facilitate the formation of MOH and chemical adsorption of OH– groups, which are the rate-limiting steps for these catalysts according to our Tafel analysis. Remarkably, the tri-metallic FeCoNiP pre-catalyst exhibits exceptionally high apparent and intrinsic OER activities, requiring only 200 mV to deliver 10 mA cm–2 and showing a high turnover frequency (TOF) of ≥0.94 s–1 at the overpotential of 350 mV. PMID:29780476

Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc–Air Battery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hui; Li, Qi; Wen, Peng

Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this paper, highly monodisperse CoP and Co 2P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co 2P NCs show higher OER performance owing to easier formation of plentiful Co 2P@COOH heterojunctions. Density functional theory calculation results indicate that themore » desorption of OH* from cobalt sites is the rate-limiting step for both CoP and Co 2P in ORR and that the high content of phosphide can lower the reaction barrier. A water electrolyzer constructed with a CoP NC cathode and a Co 2P NC anode can achieve a current density of 10 mA cm -2 at 1.56 V, comparable even to the noble metal-based Pt/C and RuO 2/C pair. Finally and furthermore, the CoP NCs are employed as an air cathode in a primary zinc–air battery, exhibiting a high power density of 62 mW cm -2 and good stability.« less

Colloidal Cobalt Phosphide Nanocrystals as Trifunctional Electrocatalysts for Overall Water Splitting Powered by a Zinc–Air Battery

DOE PAGES

Li, Hui; Li, Qi; Wen, Peng; ...

2018-01-15

Highly efficient and stable electrocatalysts, particularly those that are capable of multifunctionality in the same electrolyte, are in high demand for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). In this paper, highly monodisperse CoP and Co 2P nanocrystals (NCs) are synthesized using a robust solution-phase method. The highly exposed (211) crystal plane and abundant surface phosphide atoms make the CoP NCs efficient catalysts toward ORR and HER, while metal-rich Co 2P NCs show higher OER performance owing to easier formation of plentiful Co 2P@COOH heterojunctions. Density functional theory calculation results indicate that themore » desorption of OH* from cobalt sites is the rate-limiting step for both CoP and Co 2P in ORR and that the high content of phosphide can lower the reaction barrier. A water electrolyzer constructed with a CoP NC cathode and a Co 2P NC anode can achieve a current density of 10 mA cm -2 at 1.56 V, comparable even to the noble metal-based Pt/C and RuO 2/C pair. Finally and furthermore, the CoP NCs are employed as an air cathode in a primary zinc–air battery, exhibiting a high power density of 62 mW cm -2 and good stability.« less

Potential for use of indium phosphide solar cells in the space radiation environment

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1985-01-01

Indium phosphide solar cells were observed to have significantly higher radiation resistance than either GaAs or Si after exposure to 10 MeV proton irradiation data and previous 1 MeV electron data together with projected efficiencies for InP, it was found that these latter cells produced more output power than either GaAs or Si after specified fluences of 10 MeV protons and 1 MeV electrons. Estimates of expected performance in a proton dominated space orbit yielded much less degradation for InP when compared to the remaining two cell types. It was concluded that, with additional development to increase efficiency, InP solar cells would perform significantly better than either GaAs or Si in the space radiation environment.

Chemical nature of silicon nitride-indium phosphide interface and rapid thermal annealing for InP MISFETs

NASA Technical Reports Server (NTRS)

Biedenbender, M. D.; Kapoor, V. J.

1990-01-01

A rapid thermal annealing (RTA) process in pure N2 or pure H2 was developed for ion-implanted and encapsulated indium phosphide compound semiconductors, and the chemical nature at the silicon nitride-InP interface before and after RTA was examined using XPS. Results obtained from SIMS on the atomic concentration profiles of the implanted silicon in InP before and after RTA are presented, together with electrical characteristics of the annealed implants. Using the RTA process developed, InP metal-insulator semiconductor FETs (MISFETS) were fabricated. The MISFETS prepared had threshold voltages of +1 V, transconductance of 27 mS/mm, peak channel mobility of 1200 sq cm/V per sec, and drain current drift of only 7 percent.

Synthesis and x-ray characterization of cobalt phosphide (Co₂P) nanorods for the oxygen reduction reaction

DOE PAGES

Doan-Nguyen, Vicky V.T.; Su, Dong; Zhang, Sen; ...

2015-07-14

Low temperature fuel cells are clean, effective alternative fuel conversion technology. Oxygen reduction reaction (ORR) at the fuel cell cathode has required Pt as the electrocatalyst for high activity and selectivity of the four-electron reaction pathway. Targeting a less expensive, earth abundant alternative, we have developed the synthesis of cobalt phosphide (Co₂P) nanorods for ORR. Characterization techniques that include total X-ray scattering and extended X-ray absorption fine structure revealed a deviation of the nanorods from bulk crystal structure with a contraction along the b orthorhombic lattice parameter. The carbon supported nanorods have comparable activity but are remarkably more stable thanmore » conventional Pt catalysts for the oxygen reduction reaction in alkaline environments.« less

GaAsP on GaP top solar cells

NASA Technical Reports Server (NTRS)

Mcneely, J. B.; Negley, G. H.; Barnett, A. M.

1985-01-01

GaAsP on GaP top solar cells as an attachment to silicon bottom solar cells are being developed. The GaAsP on GaP system offers several advantages for this top solar cell. The most important is that the gallium phosphide substrate provides a rugged, transparent mechanical substrate which does not have to be removed or thinned during processing. Additional advantages are that: (1) gallium phosphide is more oxidation resistant than the III-V aluminum compounds, (2) a range of energy band gaps higher than 1.75 eV is readily available for system efficiency optimization, (3) reliable ohmic contact technology is available from the light-emitting diode industry, and (4) the system readily lends itself to graded band gap structures for additional increases in efficiency.

Effects of P/Ni ratio and Ni content on performance of γ-Al2O3-supported nickel phosphides for deoxygenation of methyl laurate to hydrocarbons

NASA Astrophysics Data System (ADS)

Zhang, Zhena; Tang, Mingxiao; Chen, Jixiang

2016-01-01

γ-Al2O3-supported nickel phosphides (mNi-Pn) were prepared by the TPR method and tested for the deoxygenation of methyl laurate to hydrocarbons. The effects of the P/Ni ratio (n = 1.0-2.5) and Ni content (m = 5-15 wt.%) in the precursors on their structure and performance were investigated. Ni/γ-Al2O3 was also studied for comparison. It was found that the formation of AlPO4 in the precursor inhibited the reduction of phosphate and so the formation of nickel phosphides. With increasing the P/Ni ratio and Ni content, the Ni, Ni3P, Ni12P5 and Ni2P phases orderly formed, accompanying with the increases of their particle size and the amount of weak acid sites (mainly due to P-OH group), while the CO uptake and the amount of medium strong acid sites (mainly related to Ni sites) reached maximum on 10%Ni-P1.5. In the deoxygenation reaction, compared with Ni/γ-Al2O3, the mNi-Pn catalysts showed much lower activities for decarbonylation, Csbnd C hydrogenolysis and methanation due to the ligand and ensemble effects of P. The conversion and the selectivity to n-C11 and n-C12 hydrocarbons achieved maximum on 10%Ni-P 2.0 for the 10%Ni-Pn catalysts and on 8%Ni-P2.0 for the mNi-P2.0 catalysts, while the turnover frequency (TOF) of methyl laurate mainly increased with the P/Ni ratio and Ni content. We propose that TOF was influenced by the nickel phosphide phases, the catalyst acidity and the particle size as well as the synergetic effect between the Ni site and acid site. Again, the hydrodeoxygenation pathway of methyl laurate was promoted with increasing P/Ni ratio and Ni content, ascribed to the phase change in the order of Ni, Ni3P, Ni12P5 and Ni2P in the prepared catalysts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendoza-Garcia, Adriana; Zhu, Huiyuan; Yu, Yongsheng

Presented here is a facile approach to bimetallic phosphides, Co-Fe-P, via high-temperature (300°C) reaction between Co-Fe-O nanoparticles and trioctylphosphine. The growth of Co-Fe-P from the Co-Fe-O is anisotropic. As a result, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both nanorod and the sea-urchin-arm dimensions controlled by Co/Fe ratios. The Co-Fe-P structure, especially the sea-urchin-like (Co 0.54Fe 0.46) 2P, shows enhanced catalysis for oxygen evolution reaction in KOH with its catalytic efficiency surpassing Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallicmore » phosphides for important catalysis and energy storage applications.« less

Chemical shielding properties for BN, BP, AlN, and AlP nanocones: DFT studies

NASA Astrophysics Data System (ADS)

Mirzaei, Mahmoud; Yousefi, Mohammad; Meskinfam, Masoumeh

2012-06-01

The properties of boron nitride (BN), boron phosphide (BP), aluminum nitride (AlN), and aluminum phosphide (AlP) nanocones were investigated by density functional theory (DFT) calculations. The investigated structures were optimized and chemical shielding (CS) properties including isotropic and anisotropic CS parameters were calculated for the atoms of the optimized structures. The magnitudes of CS parameters were observed to be mainly dependent on the bond lengths of considered atoms. The results indicated that the atoms could be divided into atomic layers due to the similarities of their CS properties for the atoms of each layer. The trend means that the atoms of each layer detect almost similar electronic environments. Moreover, the atoms at the apex and mouth of nanocones exhibit different properties with respect to the other atomic layers.

Indium phosphide solar cells - Status and prospects for use in space

NASA Technical Reports Server (NTRS)

Weinberg, I.; Brinker, D. J.

1986-01-01

The current status of indium phosphide cell research is reviewed and state of the art efficiencies compared to those of GaAs and Si. It is shown that the radiation resistance of InP cells is superior to that of either GaAs or Si under 1 MeV electron and 10 MeV proton irradiation. Using lightweight blanket technology, a SEP array structure and projected cell efficiencies, array specific powers are obtained for all three cell types. Array performance is calculated as a function of time in orbit. The results indicate that arrays using InP cells can outperform those using GaAs or Si in orbits where radiation is a significant cell degradation factor. It is concluded that InP solar cells are excellent prospects for future use in the space radiation environment.

Highly selective dry etching of GaP in the presence of AlxGa1–xP with a SiCl4/SF6 plasma

NASA Astrophysics Data System (ADS)

Hönl, Simon; Hahn, Herwig; Baumgartner, Yannick; Czornomaz, Lukas; Seidler, Paul

2018-05-01

We present an inductively coupled-plasma reactive-ion etching process that simultaneously provides both a high etch rate and unprecedented selectivity for gallium phosphide (GaP) in the presence of aluminum gallium phosphide (AlxGa1–xP). Utilizing mixtures of silicon tetrachloride (SiCl4) and sulfur hexafluoride (SF6), selectivities exceeding 2700:1 are achieved at GaP etch rates above 3000 nm min‑1. A design of experiments has been employed to investigate the influence of the inductively coupled-plasma power, the chamber pressure, the DC bias and the ratio of SiCl4 to SF6. The process enables the use of thin AlxGa1–xP stop layers even at aluminum contents of a few percent.

Nucleation of intragranular ferrite in Fe-Ni-P alloys

NASA Astrophysics Data System (ADS)

Narayan, C.; Goldstein, J. I.

1984-05-01

The nucleation of intragranular ferrite from austenite in Fe-Ni-P alloys was investigated in order to understand the development of the Widmanstätten pattern in iron meteorites. Alloys containing 5 to 10 wt pct Ni and 0 to 1 wt pct P were used to simulate iron meteorite compositions. In the isothermal and controlled cooling experiments the reaction path γ → α + γ serves only to nucleate ferrite along austenite grain boundaries. It is necessary for (FeNi)3P to be present within y grains in order to nucleate intragranular ferrite. The reaction path γ → γ + phosphide → α + γ + phosphide yields rod shaped ferrite nuclei that bear a near Kurdjumov-Sachs orientation relationship with the surrounding matrix. The precipitation of ferrite, both along grain boundaries and within the austenite grains, is suppressed in the absence of P.

Direct Band Gap Wurtzite Gallium Phosphide Nanowires

PubMed Central

2013-01-01

The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555–690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality. PMID:23464761

Indium phosphide solar cells: status and prospects for use in space

NASA Technical Reports Server (NTRS)

Weinberg, I.; Brinker, D. J.

1986-01-01

The current status of indium phosphide cell research is reviewed and state of the art efficiencies compared to those of GaAs and Si. It is shown that the radiation resistance of InP cells is superior to that of either GaAs or Si under 1 MeV electron and 10 MeV proton irradiation. Using lightweight blanket technology, a SEP array structure and projected cell efficiencies, array specific powers are obtained for all three cell types. Array performance is calculated as a function of time in orbit. The results indicate that arrays using InP cells can outperform those using GaAs or Si in orbits where radiation is a significant cell degradation factor. It is concluded that InP solar cells are excellent prospects for future use in the space radiation environment.

New intermetallic MIrP (M=Ti, Zr, Nb, Mo) and MgRuP compounds related with MoM'P (M'=Ni and Ru) superconductor

NASA Astrophysics Data System (ADS)

Kito, Hijiri; Iyo, Akira; Wada, Toshimi

2011-01-01

Using a cubic-anvil high-pressure apparatus, ternary iridium phosphides MIrP (M=Ti, Zr, Nb, Mo) and MgRuP have been prepared by reaction of stoichiometric amounts of each metal and phosphide powders at around 2 Gpa and above 1523 K for the first time. The structure of these compounds prepared at high-pressure has been characterized by X-ray powder diffraction. Diffraction lines of these compounds are assigned by the index of the Co2Si-type structure. The electrical resistivity and the d.c magnetic susceptibility of MIrP (M=Ti, Zr, Nb, Mo) have measured at low temperatures. Unfortunately, no superconducting transition for MIrP (M=Ti, Zr, Nb, Mo) and MgRuP are observed down to 2 K.

Comparative studies on mitochondrial electron transport chain complexes of Sitophilus zeamais treated with allyl isothiocyanate and calcium phosphide.

PubMed

Zhang, Chao; Wu, Hua; Zhao, Yuan; Ma, Zhiqing; Zhang, Xing

2016-01-01

With Sitophilus zeamais as the target organism, the present study for the first time attempted to elucidate the comparative effects between allyl isothiocyanate (AITC) and calcium phosphide (Ca3P2), exposure on mitochondrial electron transport chain (ETC.) complex I & IV and their downstream effects on enzymes relevant to reactive oxygen species (ROS). In vivo, both AITC and Ca3P2 inhibited complex I and IV with similar downstream effects. In contrast with Ca3P2, the inhibition of complex I caused by AITC was dependent on time and dose. In vitro, AITC inhibited complex IV more significantly than complex I. These results indicate that mitochondrial complex IV is the primary target of AITC, and that complex I is another potential target. Copyright © 2015 Elsevier B.V. All rights reserved.

ANALYSIS OF THE WATER-SPLITTING CAPABILITIES OF GALLIUM INDIUM PHOSPHIDE NITRIDE (GaInPN)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Head, J.; Turner, J.

2007-01-01

With increasing demand for oil, the fossil fuels used to power society’s vehicles and homes are becoming harder to obtain, creating pollution problems and posing hazard’s to people’s health. Hydrogen, a clean and effi cient energy carrier, is one alternative to fossil fuels. Certain semiconductors are able to harness the energy of solar photons and direct it into water electrolysis in a process known as photoelectrochemical water-splitting. P-type gallium indium phosphide (p-GaInP2) in tandem with GaAs is a semiconductor system that exhibits water-splitting capabilities with a solar-tohydrogen effi ciency of 12.4%. Although this material is effi cient at producing hydrogenmore » through photoelectrolysis it has been shown to be unstable in solution. By introducing nitrogen into this material, there is great potential for enhanced stability. In this study, gallium indium phosphide nitride Ga1-yInyP1-xNx samples were grown using metal-organic chemical vapor deposition in an atmospheric-pressure vertical reactor. Photocurrent spectroscopy determined these materials to have a direct band gap around 2.0eV. Mott-Schottky analysis indicated p-type behavior with variation in fl atband potentials with varied frequencies and pH’s of solutions. Photocurrent onset and illuminated open circuit potential measurements correlated to fl atband potentials determined from previous studies. Durability analysis suggested improved stability over the GaInP2 system.« less

Window structure for passivating solar cells based on gallium arsenide

NASA Technical Reports Server (NTRS)

Barnett, Allen M. (Inventor)

1985-01-01

Passivated gallium arsenide solar photovoltaic cells with high resistance to moisture and oxygen are provided by means of a gallium arsenide phosphide window graded through its thickness from arsenic rich to phosphorus rich.

Elastic, magnetic and electronic properties of iridium phosphide Ir 2P

DOE PAGES

Wang, Pei; Wang, Yonggang; Wang, Liping; ...

2016-02-24

Cubic (space group: Fm3¯m) iridium phosphide, Ir 2P, has been synthesized at high pressure and high temperature. Angle-dispersive synchrotron X-ray diffraction measurements on Ir 2P powder using a diamond-anvil cell at room temperature and high pressures (up to 40.6 GPa) yielded a bulk modulus of B 0 = 306(6) GPa and its pressure derivative B 0'= 6.4(5). Such a high bulk modulus attributed to the short and strongly covalent Ir-P bonds as revealed by first – principles calculations and three-dimensionally distributed [IrP 4] tetrahedron network. Indentation testing on a well–sintered polycrystalline sample yielded the hardness of 11.8(4) GPa. Relatively lowmore » shear modulus of ~64 GPa from theoretical calculations suggests a complicated overall bonding in Ir 2P with metallic, ionic, and covalent characteristics. Additionally, a spin glass behavior is indicated by magnetic susceptibility measurements.« less

Magneto-optical far-infrared absorption spectroscopy of the hole states of indium phosphide

NASA Astrophysics Data System (ADS)

Lewis, R. A.; Wang, Y.-J.

2005-03-01

Far-infrared absorption spectroscopy in magnetic fields of up to 30 T of the zinc acceptor impurity in indium phosphide has revealed for the first time a series of free-hole transitions (Landau-related series) in addition to the familiar bound-hole transitions (Lyman series) as well as hitherto unobserved phonon replicas of both series. Analysis of these data permits the simultaneous direct experimental determination of (i) the hole effective mass, (ii) the species-specific binding energy of the acceptor impurity, (iii) the absolute energy levels of the acceptor excited states of both odd and even parity, (iv) more reliable, and in some cases the only, g factors for acceptor states, through relaxation of the selection rules for phonon replicas, and (v) the LO phonon energy. The method is applicable to other semiconductors and may lead to the reappraisal of their physical parameters.

High-Performance Rh 2 P Electrocatalyst for Efficient Water Splitting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Haohong; Li, Dongguo; Tang, Yan

2017-04-05

Search for active, stable and cost-efficient electrocatalysts for hydrogen production via water splitting could make substantial impact to the energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high surface area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C NCs exhibit remarkable performance for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) compared to Rh/C and Pt/C catalysts. The atomic structure of the rhodium phosphide nanocubes was directly observed by annular dark-field scanning transmission electron microscopy (ADF-STEM),more » which revealed phosphorous-rich outermost atomic layer. Combined experimental and computational studies suggest that surface phosphorous plays crucial role in determining the robust catalyst properties.« less

An in-situ phosphorus source for the synthesis of Cu 3P and the subsequent conversion to Cu 3PS 4 nanoparticle clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheets, Erik J.; Stach, Eric A.; Yang, Wei -Chang

2015-09-20

The search for alternative earth abundant semiconducting nanocrystals for sustainable energy applications has brought forth the need for nanoscale syntheses beyond bulk synthesis routes. Of particular interest are metal phosphides and derivative I-V-VI chalcogenides including copper phosphide (Cu 3P) and copper thiophosphate (Cu 3PS 4). Herein, we report a one-pot, solution-based synthesis of Cu 3P nanocrystals utilizing an in-situ phosphorus source: phosphorus pentasulfide (P 2S 5) in trioctylphosphine (TOP). By injecting this phosphorus source into a copper solution in oleylamine (OLA), uniform and size controlled Cu 3P nanocrystals with a phosphorous-rich surface are synthesized. The subsequent reaction of the Cumore » 3P nanocrystals with decomposing thiourea forms nanoscale Cu 3PS 4 particles having p-type conductivity and an effective optical band gap of 2.36 eV.« less

A combined kick-out and dissociative diffusion mechanism of grown-in Be in InGaAs and InGaAsP. A new finite difference-Bairstow method for solution of the diffusion equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koumetz, Serge D., E-mail: Serge.Koumetz@univ-rouen.fr; Martin, Patrick; Murray, Hugues

Experimental results on the diffusion of grown-in beryllium (Be) in indium gallium arsenide (In{sub 0.53}Ga{sub 0.47}As) and indium gallium arsenide phosphide (In{sub 0.73}Ga{sub 0.27}As{sub 0.58}P{sub 0.42}) gas source molecular beam epitaxy alloys lattice-matched to indium phosphide (InP) can be successfully explained in terms of a combined kick-out and dissociative diffusion mechanism, involving neutral Be interstitials (Be{sub i}{sup 0}), singly positively charged gallium (Ga), indium (In) self-interstitials (I{sub III}{sup +}) and singly positively charged Ga, In vacancies (V{sub III}{sup +}). A new numerical method of solution to the system of diffusion equations, based on the finite difference approximations and Bairstow's method,more » is proposed.« less

Solar cells with gallium phosphide/silicon heterojunction

NASA Astrophysics Data System (ADS)

Darnon, Maxime; Varache, Renaud; Descazeaux, Médéric; Quinci, Thomas; Martin, Mickaël; Baron, Thierry; Muñoz, Delfina

2015-09-01

One of the limitations of current amorphous silicon/crystalline silicon heterojunction solar cells is electrical and optical losses in the front transparent conductive oxide and amorphous silicon layers that limit the short circuit current. We propose to grow a thin (5 to 20 nm) crystalline Gallium Phosphide (GaP) by epitaxy on silicon to form a more transparent and more conducting emitter in place of the front amorphous silicon layers. We show that a transparent conducting oxide (TCO) is still necessary to laterally collect the current with thin GaP emitter. Larger contact resistance of GaP/TCO increases the series resistance compared to amorphous silicon. With the current process, losses in the IR region associated with silicon degradation during the surface preparation preceding GaP deposition counterbalance the gain from the UV region. A first cell efficiency of 9% has been obtained on ˜5×5 cm2 polished samples.

Molybdenum Disulfide as a Protection Layer and Catalyst for Gallium Indium Phosphide Solar Water Splitting Photocathodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Britto, Reuben J.; Benck, Jesse D.; Young, James L.

2016-06-02

Gallium indium phosphide (GaInP2) is a semiconductor with promising optical and electronic properties for solar water splitting, but its surface stability is problematic as it undergoes significant chemical and electrochemical corrosion in aqueous electrolytes. Molybdenum disulfide (MoS2) nanomaterials are promising to both protect GaInP2 and to improve catalysis since MoS2 is resistant to corrosion and also possesses high activity for the hydrogen evolution reaction (HER). In this work, we demonstrate that GaInP2 photocathodes coated with thin MoS2 surface protecting layers exhibit excellent activity and stability for solar hydrogen production, with no loss in performance (photocurrent onset potential, fill factor, andmore » light limited current density) after 60 hours of operation. This represents a five-hundred fold increase in stability compared to bare p-GaInP2 samples tested in identical conditions.« less

Fabrication and properties of gallium phosphide variable colour displays

NASA Technical Reports Server (NTRS)

Effer, D.; Macdonald, R. A.; Macgregor, G. M.; Webb, W. A.; Kennedy, D. I.

1973-01-01

The unique properties of single-junction gallium phosphide devices incorporating both red and green radiative recombination centers were investigated in application to the fabrication of monolithic 5 x 7 displays capable of displaying symbolic and alphanumeric information in a multicolor format. A number of potentially suitable material preparation techniques were evaluated in terms of both material properties and device performance. Optimum results were obtained for double liquid-phase-epitaxial process in which an open-tube dipping technique was used for n-layer growth and a sealed tipping procedure for subsequent p-layer growth. It was demonstrated that to prepare devices exhibiting a satisfactory range of dominant wavelengths which can be perceived as distinct emission colors extending from the red through green region of the visible spectrum involves a compromise between the material properties necessary for efficient red emission and those considered optimum for efficient green emission.

Ab-initio calculations of electronic, transport, and structural properties of boron phosphide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ejembi, J. I.; Nwigboji, I. H.; Franklin, L.

2014-09-14

We present results from ab-initio, self-consistent density functional theory calculations of electronic and related properties of zinc blende boron phosphide (zb-BP). We employed a local density approximation potential and implemented the linear combination of atomic orbitals formalism. This technique follows the Bagayoko, Zhao, and Williams method, as enhanced by the work of Ekuma and Franklin. The results include electronic energy bands, densities of states, and effective masses. The calculated band gap of 2.02 eV, for the room temperature lattice constant of a=4.5383 Å, is in excellent agreement with the experimental value of 2.02±0.05 eV. Our result for the bulk modulus,more » 155.7 GPa, agrees with experiment (152–155 GPa). Our predictions for the equilibrium lattice constant and the corresponding band gap, for very low temperatures, are 4.5269 Å and 2.01 eV, respectively.« less

Evaluation of Silica-Supported Metal and Metal Phosphide Nanoparticle Catalysts for the Hydrodeoxygenation of Guaiacol Under Ex Situ Catalytic Fast Pyrolysis Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Griffin, Michael B.; Baddour, Frederick G.; Habas, Susan E.

A series of metal and metal phosphide catalysts were investigated for the hydrodeoxygenation of guaiacol under ex situ catalytic fast pyrolysis (CFP) conditions (350 °C, 0.5 MPa, 12 H 2:1 guaiacol, weight hourly space velocity 5 h $-$1). Ligand-capped Ni, Pt, Rh, Ni 2P, and Rh 2P nanoparticles (NPs) were prepared using solution-phase synthesis techniques and dispersed on a silica support. For the metal phosphide NP-catalysts, a synthetic route that relies on the decomposition of a single molecular precursor was employed. The reactivity of the NP-catalysts was compared to a series of reference materials including Ni/SiO 2 and Pt/SiO 2more » prepared using incipient wetness (IW) impregnation and a commercial (com) Pt/SiO 2 catalyst. The NP-Ni/SiO 2 catalyst exhibited the largest reduction in the oxygen mol% of the organic phase and outperformed the IW-Ni/SiO 2 material. Although it was less active for guaiacol conversion than NP-Ni/SiO 2, NP-Rh2P/SiO 2 demonstrated the largest production of completely deoxygenated products and the highest selectivity to anisole, benzene, and cyclohexane, suggesting that it is a promising catalyst for deoxygenation of aryl-OH bonds. Finally, the com-Pt/SiO 2 and IW-Pt/SiO 2 catalyst exhibited the highest normalized rate of guaiacol conversion per m 2 and per gram of active phase, respectively, but did not produce any completely deoxygenated products.« less

Multiple quarantine treatment using bale compression and a three-day fumigation to control Hessian fly (Diptera: Cecidomyiidae) in exported hay.

PubMed

Yokoyama, Victoria Y

2014-06-01

A multiple quarantine treatment was developed to control Hessian fly puparia, Mayetiola destructor (Say), the stage of regulatory concern in exported hay. In a commercial test using 51.589 puparia, no insects survived to the adult stage after exposure to bale compression at 137 kg/cm2 and fumigation with 61 g/28.3 m3 hydrogen phosphide for 3d. The puparia were fumigated in infested wheat seedlings in cloth bags inside compressed timothy bales placed in different locations in three replicate freight containers in a heated building. Fumigant concentrations were 345-522 ppm on day 1; 580-824 ppm on day 2; and 680-861 ppm on day 3. Monitored temperatures were < 20 degrees C in all locations allowing the fumigation temperature to be established at > or = 20 degrees C. Copper detection plate corrosion values were severe inside the freight container doors, and moderate in the middle of bales in all locations, providing visual confirmation of exposure to hydrogen phosphide. Hydrogen phosphide residues in exposed hay bales were found in trace amounts, below the U.S. Environmental Protection Agency tolerance of 0.1 ppm for animal feeds. Timothy hay used in the commercial test is the representative species for all previously exported hay and straw species. The new multiple quarantine treatment is proposed for use with all previously tested bale sizes and wrapper styles for which 3-d fumigation data has been reported, and for bales and wrappers derived from those tested.

Bimetallic Cobalt-Based Phosphide Zeolitic Imidazolate Framework: CoP x Phase-Dependent Electrical Conductivity and Hydrogen Atom Adsorption Energy for Efficient Overall Water Splitting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Junhua; Zhu, Chengzhou; Xu, Bo Z.

Cobalt-based bimetallic phosphide encapsulated in carbonized zeolitic imadazolate frameworks has been successfully synthesized and showed excellent activities toward both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory calculation and electrochemical measurements reveal that the electrical conductivity and electrochemical activity are closely associated with the Co2P/CoP mixed phase behaviors upon Cu metal doping. This relationship is found to be the decisive factor for enhanced electrocatalytic performance. Moreover, the precise control of Cu content in Co-host lattice effectively alters the Gibbs free energy for H* adsorption, which is favorable for facilitating reaction kinetics. Impressively, an optimized performance hasmore » been achieved with mild Cu doping in Cu0.3Co2.7P/nitrogen-doped carbon (NC) which exhibits an ultralow overpotential of 0.19 V at 10 mA cm–2 and satisfying stability for OER. Cu0.3Co2.7P/NC also shows excellent HER activity, affording a current density of 10 mA cm–2 at a low overpotential of 0.22 V. In addition, a homemade electrolyzer with Cu0.3Co2.7P/NC paired electrodes shows 60% larger current density than Pt/ RuO2 couple at 1.74 V, along with negligible catalytic deactivation after 50 h operation. The manipulation of electronic structure by controlled incorporation of second metal sheds light on understanding and synthesizing bimetallic transition metal phosphides for electrolysis-based energy conversion.« less

Evaluation of Silica-Supported Metal and Metal Phosphide Nanoparticle Catalysts for the Hydrodeoxygenation of Guaiacol Under Ex Situ Catalytic Fast Pyrolysis Conditions

DOE PAGES

Griffin, Michael B.; Baddour, Frederick G.; Habas, Susan E.; ...

2015-09-30

A series of metal and metal phosphide catalysts were investigated for the hydrodeoxygenation of guaiacol under ex situ catalytic fast pyrolysis (CFP) conditions (350 °C, 0.5 MPa, 12 H 2:1 guaiacol, weight hourly space velocity 5 h $-$1). Ligand-capped Ni, Pt, Rh, Ni 2P, and Rh 2P nanoparticles (NPs) were prepared using solution-phase synthesis techniques and dispersed on a silica support. For the metal phosphide NP-catalysts, a synthetic route that relies on the decomposition of a single molecular precursor was employed. The reactivity of the NP-catalysts was compared to a series of reference materials including Ni/SiO 2 and Pt/SiO 2more » prepared using incipient wetness (IW) impregnation and a commercial (com) Pt/SiO 2 catalyst. The NP-Ni/SiO 2 catalyst exhibited the largest reduction in the oxygen mol% of the organic phase and outperformed the IW-Ni/SiO 2 material. Although it was less active for guaiacol conversion than NP-Ni/SiO 2, NP-Rh2P/SiO 2 demonstrated the largest production of completely deoxygenated products and the highest selectivity to anisole, benzene, and cyclohexane, suggesting that it is a promising catalyst for deoxygenation of aryl-OH bonds. Finally, the com-Pt/SiO 2 and IW-Pt/SiO 2 catalyst exhibited the highest normalized rate of guaiacol conversion per m 2 and per gram of active phase, respectively, but did not produce any completely deoxygenated products.« less

Zinc phosphide

Integrated Risk Information System (IRIS)

Zinc phoshide ; CASRN 1314 - 84 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

40 CFR 180.284 - Zinc phosphide; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... agricultural commodities as follows: Commodity Parts per million Alfalfa, forage 0.2 Alfalfa, hay 0.2 Barley... Expiration/Revocation Date Alfalfa, forage 1.0 12/31/05 Alfalfa, hay 1.0 12/31/05 Clover, forage 0.1 12/31/05...

Corrosion of Cellular Metals in Marine Environments

DTIC Science & Technology

2006-09-30

phosphides and silicides during the brazing process. Phosphorus, particularly, which is very proficient at depressing the filler alloy melting point...theories of corrosion were constructed for isolated AL-6XN in neutral sodium chloride solutions. This also demonstrated the intrinsic resistance of AL

Engineering a nanotubular mesoporous cobalt phosphide electrocatalyst by the Kirkendall effect towards highly efficient hydrogen evolution reactions.

PubMed

Miao, Yue-E; Li, Fei; Zhou, Yu; Lai, Feili; Lu, Hengyi; Liu, Tianxi

2017-11-02

Tailoring the size and controlling the morphology of particular nano-architectures are considered as two promising strategies to improve the catalytic performance of metal nanocrystals towards hydrogen evolution reactions (HERs). Herein, mesoporous cobalt phosphide nanotubes (CoP-NTs) with a three-dimensional network structure have been obtained through a facile and efficient electrospinning technique combined with thermal stabilization and phosphorization treatments. The thermal stabilization process has been demonstrated to play a key role in the morphological tailoring of Co 3 O 4 nanotubes (Co 3 O 4 -NTs). As a result, the CoP-NTs show one-dimensional hollow tubular architecture instead of forming a worm-like tubular CoP structure (W-CoP-NTs) or severely aggregated CoP powder (CoP-NPs) which originate from the Co 3 O 4 nanotubes without thermal stabilization treatment and Co 3 O 4 nanoparticles, respectively. Satisfyingly, under an optimized phosphorization degree, the CoP-NT electrode exhibits a low onset overpotential of 53 mV with a low Tafel slope of 50 mV dec -1 during the HER process. Furthermore, the CoP-NT electrode is capable of driving a large cathodic current density of 10 mA cm -2 at an overpotential of 152 mV, which is much lower than those of its contrast samples, i.e. CoP-NPs (211 mV) and W-CoP-NTs (230 mV). Therefore, this work provides a feasible and general strategy for constructing three-dimensionally organized mesoporous non-noble metal phosphide nanotubes as promising alternative high-performance electrocatalysts for the commercial platinum ones.

Deoxygenation of Palmitic Acid on Unsupported Transition-Metal Phosphides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peroni, Marco; Lee, Insu; Huang, Xiaoyang

Abstract Highly active bulk transition metal phosphides (WP, MoP, and Ni2P) were synthesized for the catalytic hydrodeoxygenation of palmitic acid, hexadecanol, hexadecanal, and microalgae oil. The specific activities positively correlated with the concentration of exposed metal sites, although the relative rates changed with temperature due to activation energies varying from 57 kJ·mol-1 for MoP to 142 kJ·mol-1 for WP. The reduction of the fatty acid to the aldehyde occurs through a Langmuir-Hinshelwood mechanism, where the rate-determining step is the addition of the second H to the hydrocarbon. On WP, the conversion of palmitic acid proceeds via R-CH2COOH R-CH2CHO R-CH2CH2OH R-CHCH2more » R-CH2CH3 (hydrodeoxygenation). Decarbonylation of the intermittently formed aldehyde (R-CH2COOH R-CH2CHO R-CH3) was an important pathway on MoP and Ni2P. Conversion via dehydration to a ketene, followed by its decarbonylation occurred only on Ni2P. The rates of alcohol dehydration (R-CH2CH2OH R-CHCH2) correlate with the concentration of Lewis acid sites of the phosphides. Acknowledgements The authors would like to thank Roel Prins for the critical discussion of the results. We are also grateful to Xaver Hecht for technical support. Funding by the German Federal Ministry of Food and Agriculture in the framework of the Advanced Biomass Value project (03SF0446A) is gratefully acknowledged. J.A.L. acknowledges support for his contribution by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences for exploring non-oxidic supports for deoxygenation reactions.« less

Process Development of Gallium Nitride Phosphide Core-Shell Nanowire Array Solar Cell

NASA Astrophysics Data System (ADS)

Chuang, Chen

Dilute Nitride GaNP is a promising materials for opto-electronic applications due to its band gap tunability. The efficiency of GaNxP1-x /GaNyP1-y core-shell nanowire solar cell (NWSC) is expected to reach as high as 44% by 1% N and 9% N in the core and shell, respectively. By developing such high efficiency NWSCs on silicon substrate, a further reduction of the cost of solar photovoltaic can be further reduced to 61$/MWh, which is competitive to levelized cost of electricity (LCOE) of fossil fuels. Therefore, a suitable NWSC structure and fabrication process need to be developed to achieve this promising NWSC. This thesis is devoted to the study on the development of fabrication process of GaNxP 1-x/GaNyP1-y core-shell Nanowire solar cell. The thesis is divided into two major parts. In the first parts, previously grown GaP/GaNyP1-y core-shell nanowire samples are used to develop the fabrication process of Gallium Nitride Phosphide nanowire solar cell. The design for nanowire arrays, passivation layer, polymeric filler spacer, transparent col- lecting layer and metal contact are discussed and fabricated. The property of these NWSCs are also characterized to point out the future development of Gal- lium Nitride Phosphide NWSC. In the second part, a nano-hole template made by nanosphere lithography is studied for selective area growth of nanowires to improve the structure of core-shell NWSC. The fabrication process of nano-hole templates and the results are presented. To have a consistent features of nano-hole tem- plate, the Taguchi Method is used to optimize the fabrication process of nano-hole templates.

Gallium phosphide energy converters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sims, P.E.; Dinetta, L.C.; Goetz, M.A.

1995-10-01

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp {minus}17) A/sq cm have been measured andmore » the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.« less

Gallium phosphide energy converters

NASA Astrophysics Data System (ADS)

Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

1995-10-01

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

Precipitation behavior in austenitic and ferritic steels during fast neutron irradiation and thermal aging*1

NASA Astrophysics Data System (ADS)

Kawanishi, H.; Hajima, R.; Sekimura, N.; Arai, Y.; Ishino, S.

1988-07-01

Precipitation behavior has been studied using a carbon extraction replica technique in Ti-modified Type 316 stainless steels (JPCA-2) and 9Cr-2Mo ferritic/martensitic steels (JFMS) irradiated to 8.1 × 10 24 n/m 2 at 873 and 673 K, respectively, in the experimental fast breeder reactor JOYO. Precipitate identification and compositional analysis were carried out on extracted replicas. The results were compared to those from the as-received steel and a control which had been given the same thermal as-treatment as the specimens received during irradiations. Carbides, Ti-sulphides and phosphides were precipitated in JPCA-2. Precipitate observed in JFMS included carbides, Laves-phases and phosphides. The precipitates in both steels were concluded to be stable under irradiation except for MC and M 6C in JPCA-2. Small MC particles were found precipitated in JPCA-2 during both irradiation and aging. Irradiation proved to promote the precipitation of M 6C in JPCA-2.

Effect of gas flow ratio on the microstructure and mechanical properties of boron phosphide films prepared by reactive magnetron sputtering

NASA Astrophysics Data System (ADS)

Jia, Z. C.; Zhu, J. Q.; Jiang, C. Z.; Shen, W. X.; Han, J. C.; Chen, R. R.

2011-10-01

Boron phosphide films were grown on silicon substrate by radio frequency reactive magnetron sputtering using boron target and hydrogen phosphine at different gas flow ratios (PH 3/Ar) at lower temperature. The chemical composition, microstructure and mechanical properties were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectrum, FTIR spectrum, surface profilometer and nano-indenter. The results indicate that the atomic ratio (P/B) rises from 1.06 up to 1.52 with the gas flow ratio increasing from 3/50 to 15/50. Simultaneously, the hardness and Young's modulus decrease from 25.4 GPa to 22.5 GPa, and 250.4 GPa to 238.4 GPa, respectively. Microstructure transforms from microcrystalline state to amorphous state along with the gas flow ratio increasing. Furthermore higher gas flow ratio leads to lower stress. The BP film prepared at the gas flow ratio of 3/50 can be contributed with the best properties.

Scaling Relations for Adsorption Energies on Doped Molybdenum Phosphide Surfaces

DOE PAGES

Fields, Meredith; Tsai, Charlie; Chen, Leanne D.; ...

2017-03-10

Molybdenum phosphide (MoP), a well-documented catalyst for applications ranging from hydrotreating reactions to electrochemical hydrogen evolution, has yet to be mapped from a more fundamental perspective, particularly in the context of transition-metal scaling relations. In this work, we use periodic density functional theory to extend linear scaling arguments to doped MoP surfaces and understand the behavior of the phosphorus active site. The derived linear relationships for hydrogenated C, N, and O species on a variety of doped surfaces suggest that phosphorus experiences a shift in preferred bond order depending on the degree of hydrogen substitution on the adsorbate molecule. Thismore » shift in phosphorus hybridization, dependent on the bond order of the adsorbate to the surface, can result in selective bond weakening or strengthening of chemically similar species. As a result, we discuss how this behavior deviates from transition-metal, sulfide, carbide, and nitride scaling relations, and we discuss potential applications in the context of electrochemical reduction reactions.« less

Gallium phosphide energy converters

NASA Technical Reports Server (NTRS)

Sims, P. E.; Dinetta, L. C.; Goetz, M. A.

1995-01-01

Gallium phosphide (GaP) energy converters may be successfully deployed to provide new mission capabilities for spacecraft. Betavoltaic power supplies based on the conversion of tritium beta decay to electricity using GaP energy converters can supply long term low-level power with high reliability. High temperature solar cells, also based on GaP, can be used in inward-bound missions greatly reducing the need for thermal dissipation. Results are presented for GaP direct conversion devices powered by Ni-63 and compared to the conversion of light emitted by tritiarated phosphors. Leakage currents as low as 1.2 x 10(exp -17) A/sq cm have been measured and the temperature dependence of the reverse saturation current is found to have ideal behavior. Temperature dependent IV, QE, R(sub sh), and V(sub oc) results are also presented. These data are used to predict the high-temperature solar cell and betacell performance of GaP devices and suggest appropriate applications for the deployment of this technology.

A review of aluminium phosphide poisoning and a flowchart to treat it.

PubMed

Hashemi-Domeneh, Behrooz; Zamani, Nasim; Hassanian-Moghaddam, Hossein; Rahimi, Mitra; Shadnia, Shahin; Erfantalab, Peyman; Ostadi, Ali

2016-09-01

The use of pesticides such as aluminium phosphide (AlP) has increased in the recent years and improved the quantity and quality of agricultural products in a number of developing countries. The downside is that AlP causes severe chronic and acute health effects that have reached major proportions in countries such as India, Iran, Bangladesh, and Jordan. Nearly 300,000 people die due to pesticide poisoning in the world every year. Poisoning with AlP accounts for many of these deaths. Unfortunately, at the same time, there is no standard treatment for it. The aim of this article is to give a brief review of AlP poisoning and propose a treatment flowchart based on the knowledge gained so far. For this purpose we reviewed all articles on the management of AlP poisoning published from 2000 till now. Using a modified Delphi design, we have designed a handy flowchart that could be used as a guide for AlP poisoning management of patients in emergency centres.

CoP/WS2 nanoflake heterostructures as efficient electrocatalysts for significant improvement in hydrogen evolution activity

NASA Astrophysics Data System (ADS)

Chen, Yajie; Kang, Chuanhong; Wang, Ruihong; Ren, Zhiyu; Fu, Huiying; Xiao, Yuting; Tian, Guohui

2018-06-01

The CoP/WS2 nanoflake composites were synthesized via the sulfuration and subsequent phosphidation using the pre-prepared WO2.72 nanowires as precursors. Originally, WO2.72 nanowires were prepared and followed by sulfuration to obtain WS2 nanoflakes. The as-prepared WS2 nanoflakes were used as substrates, on which the Co3O4 nanoparticles were uniformly anchored to construct the Co3O4/WS2 nanoflakes. Finally, the Co3O4/WS2 composites were subjected to phosphidation and in-situ converted into CoP/WS2 nanoflakes. Because of the dual functionalities of both CoP and WS2, the abundant interfaces as well as their synergy, the CoP/WS2 nanoflakes exhibited much higher electrocatalytic activity, smaller overpotential (-81 mV), lower Tafel slope (62 mV decade-1), and higher stability toward hydrogen-evolution reaction than those for the single CoP and WS2.

Field trials of the rodenticide gophacide against wild house mice (Mus musculus L.).

PubMed Central

Rowe, F. P.; Swinney, T.; Bradfield, A.

1975-01-01

The acute rodenticide gophacide was tested against urban infestations of the house mouse (Mus musculus L.) and treatment success was assessed from the results of census baitings conducted before and after each treatment. Seven of eight populations of mice living in premises where alternative food supplies were limited were successfully controlled when medium oatmeal bait containing gophacide at 0.1% was laid directly for 4 days. In further treatments against mice inhabiting more complex environments and having greater access to other foods, the performance of gophacide at 0.1% and at 0.25% in a wholemeal flour/pinhead oatmeal/corn oil bait was compared with that of zinc phosphide at 3.0% in the same bait-base. The poison treatments were conducted for 1 or 4 days and always after 3 days pre-baiting. Treatment success varied considerably irrespective of the type of treatment or of the poison used. In general, however, gophacide proved to be as effective as zinc phosphide for the control of mice. PMID:1054056

Ellipsometric analysis and optical absorption characterization of gallium phosphide nanoparticulate thin film

NASA Astrophysics Data System (ADS)

Zhang, Qi-Xian; Wei, Wen-Sheng; Ruan, Fang-Ping

2011-04-01

Gallium phosphide (GaP) nanoparticulate thin films were easily fabricated by colloidal suspension deposition via GaP nanoparticles dispersed in N,N-dimethylformamide. The microstructure of the film was performed by x-ray diffraction, high resolution transmission electron microscopy and field emission scanning electron microscopy. The film was further investigated by spectroscopic ellipsometry. After the model GaP+void|SiO2 was built and an effective medium approximation was adopted, the values of the refractive index n and the extinction coefficient k were calculated for the energy range of 0.75 eV-4.0 eV using the dispersion formula in DeltaPsi2 software. The absorption coefficient of the film was calculated from its k and its energy gaps were further estimated according to the Tauc equation, which were further verified by its fluorescence spectrum measurement. The structure and optical absorption properties of the nanoparticulate films are promising for their potential applications in hybrid solar cells.

49 CFR 173.52 - Classification codes and compatibility groups of explosives.

Code of Federal Regulations, 2011 CFR

2011-10-01

... one containing white phosphorus, phosphide or flammable liquid or gel or hypergolic liquid) G 1.1G1.2G 1.3G 1.4G Article containing both an explosive substance and white phosphorus H 1.2H1.3H Article...

49 CFR 173.52 - Classification codes and compatibility groups of explosives.

Code of Federal Regulations, 2010 CFR

2010-10-01

... one containing white phosphorus, phosphide or flammable liquid or gel or hypergolic liquid) G 1.1G1.2G 1.3G 1.4G Article containing both an explosive substance and white phosphorus H 1.2H1.3H Article...

Changing trends and predictors of outcome in patients with acute poisoning admitted to the intensive care.

PubMed

Jayashree, M; Singhi, S

2011-10-01

Acute poisoning in children is a medical emergency and preventable cause of morbidity and mortality. Knowledge about the nature, magnitude, outcome and predictors of outcome is necessary for management and allocation of scant resources. This is a retrospective study conducted in the Pediatric Intensive Care Unit (PICU) of an urban multi speciality teaching and referral hospital in North India from January 1993 to June 2008 to determine the epidemiology, clinical profile, outcome and predictors of outcome in children with acute poisoning. Data of 225 children with acute poisoning was retrieved from case records with respect to demographic profile, time to presentation, PRISM score, clinical features, investigations, therapeutic measures, complications and outcome in terms of survival or death. Survivors and non-survivors were compared to determine the predictors of mortality. Acute poisoning constituted 3.9% of total PICU admissions; almost all (96.9%) were accidental. The mean age of study patient's was 3.3 ± 3.1 (range 0.10-12) years with majority (61.3%) being toddlers (1-3 years). In the overall cohort, kerosene (27.1%) and prescription drugs (26.7%) were the most common causative agents followed by organophosphates (16.0%), corrosives (7.6%), carbamates (4.9%) and aluminum phosphide (4.9%). However the trends of the three 5-year interval (1993 till the end of 1997, 1998 till the end of 2002 and 2003 till the end of June 2008) revealed a significant decrease in kerosene, aluminum phosphide and iron with increase in organophosphate compound poisoning. Ninety nine (44%) patients required supplemental oxygen, of which nearly half (n = 42; 42.4%) needed mechanical ventilation. Twenty (8.9%) died; cause of death being iron poisoning in five; aluminum phosphide in four; organophosphates in three and one each because of kerosene, diesel, carbamate, corrosive, sewing machine lubricant, isoniazid, salicylate and maduramycin poisoning. There has been a significant decrease in the mortality over the years. The non-survivors were older, had a higher PRISM score and hypotension at admission and higher need for oxygen and ventilation. On multiple logistic regression analysis hypotension at admission was the most significant predictor of death (adjusted odds ratio: 5.59; 95% confidence interval: 1.38-22.63; p = 0.016). Acute poisoning in children over the past 15 years has shown a changing trend with significant decrease in kerosene, iron and aluminum phosphide and an increase in organophosphate and prescription drugs. The overall mortality has decreased significantly. Hypotension at admission was the most significant predictor of death.

Chemistry of the oxophosphinidene ligand. 2. Reactivity of the anionic complexes [MCp{P(O)R*}(CO)(2)](-) (M = Mo, W; R* = 2,4,6-C(6)H(2)(t)Bu(3)) toward electrophiles based on elements different from carbon.

PubMed

Alonso, María; Alvarez, M Angeles; García, M Esther; Ruiz, Miguel A; Hamidov, Hayrullo; Jeffery, John C

2010-12-20

The anionic oxophosphinidene complexes (H-DBU)[MCp{P(O)R*}(CO)(2)] (M = Mo, W; R* = 2,4,6-C(6)H(2)(t)Bu(3); Cp = η(5)-C(5)H(5), DBU = 1,8-diazabicyclo [5.4.0] undec-7-ene) displayed multisite reactivity when faced with different electrophilic reagents. The reactions with the group 14 organochloride compounds ER(4-x)Cl(x) (E = Si, Ge, Sn, Pb) led to either phosphide-like, oxophosphinidene-bridged derivatives [MCp{P(OE')R*}(CO)(2)] (E' = SiMe(3), SiPh(3), GePh(3), GeMe(2)Cl) or to terminal oxophosphinidene complexes [MCp{P(O)R*}(CO)(2)(E')] (E' = SnPh(3), SnPh(2)Cl, PbPh(3); Mo-Pb = 2.8845(4) Å for the MoPb compound). A particular situation was found in the reaction with SnMe(3)Cl, this giving a product existing in both tautomeric forms, with the phosphide-like complex [MCp{P(OSnMe(3))R*}(CO)(2)] prevailing at room temperature and the tautomer [MCp{P(O)R*}(CO)(2)(SnMe(3))] being the unique species present below 203 K in dichloromethane solution. The title anions also showed a multisite behavior when reacting with transition-metal based electrophiles. Thus, the reactions with the complexes [M'Cp(2)Cl(2)] (M' = Ti, Zr) gave phosphide-like derivatives [MCp{P(OM')R*}(CO)(2)] (M = Mo, M' = TiCp(2)Cl, ZrCp(2)Cl; M = W, M' = ZrCp(2)Cl), displaying a bridging κ(1),κ(1)-P,O- oxophosphinidene ligand connecting MCp(CO)(2) and M'Cp(2)Cl metal fragments (W-P = 2.233(1) Å, O-Zr = 2.016(4) Å for the WZr compound]. In contrast, the reactions with the complex [AuCl{P(p-tol)(3)}] gave the metal-metal bonded derivatives trans-[MCp{P(O)R*}(CO)(2){AuP(p-tol)(3)}] (M = Mo, W; Mo-Au = 2.7071(7) Å). From all the above results it was concluded that the terminal oxophosphinidene complexes are preferentially formed under conditions of orbital control, while charge-controlled reactions tend to give derivatives with the electrophilic fragment bound to the oxygen atom of the oxophosphinidene ligand (phosphide-like, oxophosphinidene-bridged derivatives).

Thermophysical and Electronic Properties Information Analysis Center (TEPIAC): A Continuing Systematic Program on Tables of Thermophysical and Electronic Properties of Materials.

DTIC Science & Technology

1977-02-01

oxides and their mixtures, arsenides, borides, bromides , carbides , chlorides , fluoride s, nitride s, phosphides, silicides , sulfides , tellurides...ivity of alkali elements (lithium , sodium , potassium , rubi- dium , ces ium , and francium) and contains recomme nded reference values generated

Pesticide Spill Prevention and Management

DTIC Science & Technology

2009-08-01

Gentrol IGR) Strong oxidizers. Imidacloprid Oxidizing agents. Lambda-cyhalothrin Oxidizing agents, alkalis, calcium hypochlorite. Malathion... Imidacloprid Sodium salt of diphacinone Methyl Azoxystrobin Use Hard Water Detergent for: Diquat Aluminum phosphide – NOTE: See special...Hydroprene, 9.0%, emulsifiable concentrate (Gentrol IGR) Imidacloprid (Maxforce Granular Fly Bait) Imidacloprid (Maxforce Fly Spot Bait

Effects of prairie dog rodenticides on deer mice in western South Dakota

Treesearch

Michele S. Deisch; Daniel W. Uresk; Raymond L. Linder

1990-01-01

Mortality of nontarget small mammals was determined after application of three black-tailed prairie dog (Cynomys Zudovicianus) rodenticide treatments (prebaited zinc phosphide, prebaited strychnine, and strychnine alone) in western South Dakota. Immediate (September 1983) and long-term (September 1983 through August 1984) impacts on deer mouse (...

Impacts of black-tailed prairie dog rodenticides on nontarget passerines

Treesearch

Anthony D. Apa; Daniel W. Uresk; Raymond L. Linder

1991-01-01

In 1983 zinc phosphide, strychnine with prebait, and strychnine without prebait were applied to black-tailed prairie dog (Cynomys Zudovicianus) colonies in west central South Dakota. Short-term (four days later) and long-term (one year later) impacts of the rodenticides on Horned Larks (Eremophila alpestris) and other...

Synthesis and thermoelectric properties of CoP(sub 3)

NASA Technical Reports Server (NTRS)

Shields, V. B.; Caillet, T.

2002-01-01

In an effort to expand the range of operation for highly efficient, segmented thermoelectric unicouples currently being developed at JPL, skutterudite phosphides are being investigated as potential high temperature segments to supplement antimonide segments that limit the use of these unicouples at a hot-side temperature of about 873-973 K.

CYTOGENETIC EFFECTS OF PHOSPHINE INHALATION BY RODENTS

EPA Science Inventory

Phosphine (PH3) is a highly toxic grain fumigant that can be produced from the reaction of metal phosphides with water. o determine the in vivo cytogenetic effects of inhalation of PH3, male CD-1 mice were exposed to either 0, 5, 10, or 15 ppm target concentrations of PH3 for 6 h...

An economic analysis of black-tailed prairie dog (Cynomys ludovicianus) control

Treesearch

Alan R. Collins; John P. Workman; Daniel W. Uresk

1984-01-01

Black-tailed prairie dog (Cynomys ludovicianus) control by poisoning with zinc phosphide was not economically feasible in the Conata Basin of South Dakota. Economic analyses were conducted from U.S. Forest Service and rancher viewpoints. Control programs were analyzed with annual maintenance or complete retreatment of initially treated areas to...

Demography of black-tailed prairie dog populations reoccupying sites treated with rodenticide

Treesearch

R. P. Cincotta; Daniel W. Uresk; R. M. Hansen

1987-01-01

A rodenticide, zinc phosphide, was applied to remove black-tailed prairie dogs (Cynomys ludovicianus) from 6 haofa prairie dog colony in southwestern South Dakota. Another adjacent 6 ha was left untreated. The removal experiment was repeated two consecutive years. Contingency table analysis showed that the resultant population was not homogeneous;...

Intense Femtosecond Laser-Mediated Electrical Discharge Enables Preparation of Amorphous Nickel Phosphide Nanoparticles.

PubMed

Ma, Zhuo-Chen; Chen, Qi-Dai; Han, Bing; Li, He-Long; Wang, Lei; Zhang, Yong-Lai; Sun, Hong-Bo

2018-05-09

Reported here is a high-efficiency preparation method of amorphous nickel phosphide (Ni-P) nanoparticles by intense femtosecond laser irradiation of nickel sulfate and sodium hypophosphite aqueous solution. The underlying mechanism of the laser-assisted preparation was discussed in terms of the breaking of chemical bond in reactants via highly intense electric field discharge generated by the intense femtosecond laser. The morphology and size of the nanoparticles can be tuned by varying the reaction parameters such as ion concentration, ion molar ratio, laser power, and irradiation time. X-ray diffraction and transmission electron microscopy results demonstrated that the nanoparticles were amorphous. Finally, the thermogravimetric-differential thermal analysis experiment verified that the as-synthesized noncrystalline Ni-P nanoparticles had an excellent catalytic capability toward thermal decomposition of ammonium perchlorate. This strategy of laser-mediated electrical discharge under such an extremely intense field may create new opportunities for the decomposition of molecules or chemical bonds that could further facilitate the recombination of new atoms or chemical groups, thus bringing about new possibilities for chemical reaction initiation and nanomaterial synthesis that may not be realized under normal conditions.

New Intermetallic Ternary Phosphide Chalcogenide AP2-xXx (A = Zr, Hf; X = S, Se) Superconductors with PbFCl-Type Crystal Structure

NASA Astrophysics Data System (ADS)

Kitô, Hijiri; Yanagi, Yousuke; Ishida, Shigeyuki; Oka, Kunihiko; Gotoh, Yoshito; Fujihisa, Hiroshi; Yoshida, Yoshiyuki; Iyo, Akira; Eisaki, Hiroshi

2014-07-01

We have synthesized a series of intermetallic ternary phosphide chalcogenide superconductors, AP2-xXx (A = Zr, Hf; X = S, Se), using the high-pressure synthesis technique. These materials have a PbFCl-type crystal structure (space group P4/nmm) when x is greater than 0.3. The superconducting transition temperature Tc changes systematically with x, yielding dome-like phase diagrams. The maximum Tc is achieved at approximately x = 0.7, at which point the Tc is 6.3 K for ZrP2-xSex (x = 0.75), 5.5 K for HfP2-xSex (x = 0.7), 5.0 K for ZrP2-xSx (x = 0.675), and 4.6 K for Hfp2-xSx (x = 0.5). They are typical type-II superconductors and the upper and lower critical fields are estimated to be 2.92 T at 0 K and 0.021 T at 2 K for ZrP2-xSex (x = 0.75), respectively.

Vertically Emitting Indium Phosphide Nanowire Lasers.

PubMed

Xu, Wei-Zong; Ren, Fang-Fang; Jevtics, Dimitars; Hurtado, Antonio; Li, Li; Gao, Qian; Ye, Jiandong; Wang, Fan; Guilhabert, Benoit; Fu, Lan; Lu, Hai; Zhang, Rong; Tan, Hark Hoe; Dawson, Martin D; Jagadish, Chennupati

2018-06-13

Semiconductor nanowire (NW) lasers have attracted considerable research effort given their excellent promise for nanoscale photonic sources. However, NW lasers currently exhibit poor directionality and high threshold gain, issues critically limiting their prospects for on-chip light sources with extremely reduced footprint and efficient power consumption. Here, we propose a new design and experimentally demonstrate a vertically emitting indium phosphide (InP) NW laser structure showing high emission directionality and reduced energy requirements for operation. The structure of the laser combines an InP NW integrated in a cat's eye (CE) antenna. Thanks to the antenna guidance with broken asymmetry, strong focusing ability, and high Q-factor, the designed InP CE-NW lasers exhibit a higher degree of polarization, narrower emission angle, enhanced internal quantum efficiency, and reduced lasing threshold. Hence, this NW laser-antenna system provides a very promising approach toward the achievement of high-performance nanoscale lasers, with excellent prospects for use as highly localized light sources in present and future integrated nanophotonics systems for applications in advanced sensing, high-resolution imaging, and quantum communications.

Isoelectronic Traps in Gallium Phosphide

NASA Astrophysics Data System (ADS)

Christian, Theresa; Alberi, Kirstin; Beaton, Daniel; Fluegel, Brian; Mascarenhas, Angelo

2015-03-01

Isoelectronic substitutional dopants can result in strongly localized exciton traps within a host bandstructure such as gallium arsenide (GaAs) or gallium phosphide (GaP). These traps have received great attention for their role in the anomalous bandgap bowing of nitrogen or bismuth-doped GaAs, creating the dramatic bandgap tunability of these unusual dilute alloys. In the wider, indirect-bandgap host material GaP, these same isoelectronic dopants create bound states within the gap that can have very high radiative efficiency and a wealth of discrete spectral transitions illuminating the symmetry of the localized excitonic trap state. We will present a comparative study of nitrogen and bismuth isoelectronic traps in GaP. Research was supported by the U. S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division under contract DE-AC36-08GO28308 and by the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF), made possible in part by the American Recovery and Reinvestment Act of 2009, administered by ORISE-ORAU under contract no. DE-AC05-06OR23100.

A comparative study on carbon, boron-nitride, boron-phosphide and silicon-carbide nanotubes based on surface electrostatic potentials and average local ionization energies.

PubMed

Esrafili, Mehdi D; Behzadi, Hadi

2013-06-01

A density functional theory study was carried out to predict the electrostatic potentials as well as average local ionization energies on both the outer and the inner surfaces of carbon, boron-nitride (BN), boron-phosphide (BP) and silicon-carbide (SiC) single-walled nanotubes. For each nanotube, the effect of tube radius on the surface potentials and calculated average local ionization energies was investigated. It is found that SiC and BN nanotubes have much stronger and more variable surface potentials than do carbon and BP nanotubes. For the SiC, BN and BP nanotubes, there are characteristic patterns of positive and negative sites on the outer lateral surfaces. On the other hand, a general feature of all of the systems studied is that stronger potentials are associated with regions of higher curvature. According to the evaluated surface electrostatic potentials, it is concluded that, for the narrowest tubes, the water solubility of BN tubes is slightly greater than that of SiC followed by carbon and BP nanotubes.

Hydrazine-Assisted Formation of Indium Phosphide (InP)-Based Nanowires and Core-Shell Composites

PubMed Central

Patzke, Greta R.; Kontic, Roman; Shiolashvili, Zeinab; Makhatadze, Nino; Jishiashvili, David

2012-01-01

Indium phosphide nanowires (InP NWs) are accessible at 440 °C from a novel vapor phase deposition approach from crystalline InP sources in hydrazine atmospheres containing 3 mol % H2O. Uniform zinc blende (ZB) InP NWs with diameters around 20 nm and lengths up to several tens of micrometers are preferably deposited on Si substrates. InP particle sizes further increase with the deposition temperature. The straightforward protocol was extended on the one-step formation of new core-shell InP–Ga NWs from mixed InP/Ga source materials. Composite nanocables with diameters below 20 nm and shells of amorphous gallium oxide are obtained at low deposition temperatures around 350 °C. Furthermore, InP/Zn sources afford InP NWs with amorphous Zn/P/O-coatings at slightly higher temperatures (400 °C) from analogous setups. At 450 °C, the smooth outer layer of InP-Zn NWs is transformed into bead-shaped coatings. The novel combinations of the key semiconductor InP with isotropic insulator shell materials open up interesting application perspectives in nanoelectronics. PMID:28809296

Forward-biased current annealing of radiation degraded indium phosphide and gallium arsenide solar cells

NASA Technical Reports Server (NTRS)

Michael, Sherif; Cypranowski, Corinne; Anspaugh, Bruce

1990-01-01

The preliminary results of a novel approach to low-temperature annealing of previously irradiated indium phosphide and gallium arsenide solar cells are reported. The technique is based on forward-biased current annealing. The two types of III-V solar cells were irradiated with 1-MeV electrons to a fluence level of (1-10) x 10 to the 14th electrons/sq cm. Several annealing attempts were made, varying all conditions. Optimum annealing was achieved when cells were injected with minority currents at a constant 90 C. The current density for each type of cell was also determined. Significant recovery of degraded parameters was achieved in both cases. However, the InP cell recovery notably exceeded the recovery in GaAs cells. The recovery is thought to be caused by current-stimulated reordering of the radiator-induced displacement damage. Both types of cell were then subjected to several cycles of irradiation and annealing. The results were also very promising. The significant recovery of degraded cell parameters at low temperature might play a major role in considerably extending the end of life of future spacecraft.

A review of episodes of zinc phosphide toxicosis in wild geese (Branta spp.) in Oregon (2004−2011)

USGS Publications Warehouse

Bildfell, Rob J.; Rumbeiha, Wilson K.; Schuler, Krysten L.; Meteyer, Carol U.; Wolff, Peregrine L.; Gillin, Colin M.

2013-01-01

Epizootic mortality in several geese species, including cackling geese (Branta hutchinsii) and Canada geese (Branta canadensis), has been recognized in the Willamette Valley of Oregon for over a decade. Birds are generally found dead on a body of water or are occasionally observed displaying neurologic clinical signs such as an inability to raise or control the head prior to death. Investigation of these epizootic mortality events has revealed the etiology to be accidental poisoning with the rodenticide zinc phosphide (Zn3P2). Gross and histologic changes are restricted to acute pulmonary congestion and edema, sometimes accompanied by distension of the upper alimentary tract by fresh grass. Geese are unusually susceptible to this pesticide; when combined with an epidemiologic confluence of depredation of specific agricultural crops by rodents and seasonal avian migration pathways, epizootic toxicosis may occur. Diagnosis requires a high index of suspicion, appropriate sample collection and handling, plus specific test calibration for this toxicant. Interagency cooperation, education of farmers regarding pesticide use, and enforcement of regulations has been successful in greatly decreasing these mortality events since 2009.

Cobalt Phosphide Hollow Polyhedron as Efficient Bifunctional Electrocatalysts for the Evolution Reaction of Hydrogen and Oxygen.

PubMed

Liu, Mengjia; Li, Jinghong

2016-01-27

The development of efficient and low-cost hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts for renewable-energy conversion techniques is highly desired. A kind of hollow polyhedral cobalt phosphide (CoP hollow polyhedron) is developed as efficient bifunctional electrocatalysts for HER and OER templated by Co-centered metal-organic frameworks. The as-prepared CoP hollow polyhedron, which have large specific surface area and high porosity providing rich catalytic active sites, show excellent electrocatalytic performances for both HER and OER in acidic and alkaline media, respectively, with onset overpotentials of 35 and 300 mV, Tafel slopes of 59 and 57 mV dec(-1), and a current density of 10 mA cm(-2) at overpotentials of 159 and 400 mV for HER and OER, respectively, which are remarkably superior to those of particulate CoP (CoP particles) and comparable to those of commercial noble-metal catalysts. In addition, the CoP hollow polyhedron also show good durability after long-term operations.

First principle study of electronic nanoscale structure of In x Ga1- x P with variable size, shape and alloying percentage

NASA Astrophysics Data System (ADS)

Hussein, M. T.; Kasim, T.; Abdulsattar, M. A.

2013-11-01

In present work, we investigate electronic properties of alloying percentage of In x Ga1- x P compound with different sizes of superlattice large unit cell (LUC) method with 8, 16, 54, and 64 nanocrystals core atoms. The size and type of alloying compound are varied so that it can be tuned to a required application. To determine properties of indium gallium phosphide nanocrystals density functional theory at the generalized-gradient approximation level coupled with LUC method is used to simulate electronic structure of zinc blende indium gallium phosphide nanocrystals that have dimensions around 2-2.8 nm. The calculated properties include lattice constant, energy gap, valence band width, cohesive energy, density of states (DOS) etc. Results show that laws that are applied at microscale alloying percentage are no more applicable at the present nanoscale. Results also show that size, shape and quantum effects are strong. Many properties fluctuate at nanoscale while others converge to definite values. DOS summarizes many of the above quantities.

Synthesis of indium phosphide nanocrystals by sonochemical method and survey of optical properties

NASA Astrophysics Data System (ADS)

Trung, Ho Minh; Duy Thien, Nguyen; Van Vu, Le; Long, Nguyen Ngoc; Hieu, Truong Kim

2013-10-01

Indium phosphide semiconductor materials (InP) have various applications in the field of semiconductor optoelectronics because of its advantages. But the making of this material is difficult due to the very weak chemical activity of In element. In this report we present a simple method to synthesize InP nanocrystals from inorganic precursors such as indium chloride (InCl3), yellow phosphorus (P4), reduction agent NaBH4 at low temperature with the aid of ultrasound. Structural, morphological and optical properties of the formed InP nanocrystals were examined by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersed X-ray analysis (EDS), Raman scattering, absorption and photoluminscence (PL) spectroscopy. After the surface treatment of InP nanocrystals with liquid hydrofluoric (HF) acid, the luminescence spectra have an enhanced intensity and consist of the peaks in the region from 500 nm to 700 nm. The intensity of these peaks strongly depends on the concentration and etching time of HF. International Workshop on Advanced Materials and Nanotechnology 2012 (IWAMN 2012).

Heterogeneous Bimetallic Phosphide/Sulfide Nanocomposite for Efficient Solar-Energy-Driven Overall Water Splitting.

PubMed

Xin, Yanmei; Kan, Xiang; Gan, Li-Yong; Zhang, Zhonghai

2017-10-24

Solar-driven overall water splitting is highly desirable for hydrogen generation with sustainable energy sources, which need efficient, earth-abundant, robust, and bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, we propose a heterogeneous bimetallic phosphide/sulfide nanocomposite electrocatalyst of NiFeSP on nickel foam (NiFeSP/NF), which shows superior electrocatalytic activity of low overpotentials of 91 mV at -10 mA cm -2 for HER and of 240 mV at 50 mA cm -2 for OER in 1 M KOH solution. In addition, the NiFeSP/NF presents excellent overall water splitting performance with a cell voltage as low as 1.58 V at a current density of 10 mA cm -2 . Combining with a photovoltaic device of a Si solar cell or integrating into photoelectrochemical (PEC) systems, the bifunctional NiFeSP/NF electrocatalyst implements unassisted solar-driven water splitting with a solar-to-hydrogen conversion efficiency of ∼9.2% and significantly enhanced PEC performance, respectively.

Hydrazine-Assisted Formation of Indium Phosphide (InP)-Based Nanowires and Core-Shell Composites.

PubMed

Patzke, Greta R; Kontic, Roman; Shiolashvili, Zeinab; Makhatadze, Nino; Jishiashvili, David

2012-12-27

Indium phosphide nanowires (InP NWs) are accessible at 440 °C from a novel vapor phase deposition approach from crystalline InP sources in hydrazine atmospheres containing 3 mol % H₂O. Uniform zinc blende (ZB) InP NWs with diameters around 20 nm and lengths up to several tens of micrometers are preferably deposited on Si substrates. InP particle sizes further increase with the deposition temperature. The straightforward protocol was extended on the one-step formation of new core-shell InP-Ga NWs from mixed InP/Ga source materials. Composite nanocables with diameters below 20 nm and shells of amorphous gallium oxide are obtained at low deposition temperatures around 350 °C. Furthermore, InP/Zn sources afford InP NWs with amorphous Zn/P/O-coatings at slightly higher temperatures (400 °C) from analogous setups. At 450 °C, the smooth outer layer of InP-Zn NWs is transformed into bead-shaped coatings. The novel combinations of the key semiconductor InP with isotropic insulator shell materials open up interesting application perspectives in nanoelectronics.

Dilute phosphide nitride materials as photocathodes for electrochemical solar energy conversion

NASA Astrophysics Data System (ADS)

Parameshwaran, Vijay; Xu, Xiaoqing; Kang, Yangsen; Harris, James; Wong, H.-S. Philip; Clemens, Bruce

2013-03-01

Dilute nitride materials have been used in a variety of III-V photonic devices, but have not been significantly explored in photoelectrochemical applications. This work focuses on using dilute phosphide nitride materials of the form (Al,In)P1-xNx as photocathodes for the generation of hydrogen fuel from solar energy. Heteroepitaxial MOCVD growth of AlPN thin films on GaP yields high quality material with a direct bandgap energy of 2.218 eV. Aligned epitaxial growth of InP and GaP nanowires on InP and Si substrates, respectively, provides a template for designing nanostructured photocathodes over a large area. Electrochemical testing of a AlPN/GaP heterostructure electrode yields up to a sixfold increase in photocurrent enhancement under blue light illumination as compared to a GaP electrode. Additionally, the AlPN/GaP electrodes exhibit no degradation in performance after galvanostatic biasing over time. These results show that (Al,In)P1-xNx is a promising materials system for use in nanoscale photocathode structures.

Phosphorus-Rich Copper Phosphide Nanowires for Field-Effect Transistors and Lithium-Ion Batteries.

PubMed

Li, Guo-An; Wang, Chiu-Yen; Chang, Wei-Chung; Tuan, Hsing-Yu

2016-09-27

Phosphorus-rich transition metal phosphide CuP2 nanowires were synthesized with high quality and high yield (∼60%) via the supercritical fluid-liquid-solid (SFLS) growth at 410 °C and 10.2 MPa. The obtained CuP2 nanowires have a high aspect ratio and exhibit a single crystal structure of monoclinic CuP2 without any impurity phase. CuP2 nanowires have progressive improvement for semiconductors and energy storages compared with bulk CuP2. Being utilized for back-gate field effect transistor (FET) measurement, CuP2 nanowires possess a p-type behavior intrinsically with an on/off ratio larger than 10(4) and its single nanowire electrical transport property exhibits a hole mobility of 147 cm(2) V(-1) s(-1), representing the example of a CuP2 transistor. In addition, CuP2 nanowires can serve as an appealing anode material for a lithium-ion battery electrode. The discharge capacity remained at 945 mA h g(-1) after 100 cycles, showing a good capacity retention of 88% based on the first discharge capacity. Even at a high rate of 6 C, the electrode still exhibited an outstanding result with a capacity of ∼600 mA h g(-1). Ex-situ transmission electron microscopy and CV tests demonstrate that the stability of capacity retention and remarkable rate capability of the CuP2 nanowires electrode are attributed to the role of the metal phosphide conversion-type lithium storage mechanism. Finally, CuP2 nanowire anodes and LiFePO4 cathodes were assembled into pouch-type lithium batteries offering a capacity over 60 mA h. The full cell shows high capacity and stable capacity retention and can be used as an energy supply to operate electronic devices such as mobile phones and mini 4WD cars.

Novel, high-activity hydroprocessing catalysts: Iron group phosphides

NASA Astrophysics Data System (ADS)

Wang, Xianqin

A series of iron, cobalt and nickel transition metal phosphides was synthesized by means of temperature-programmed reduction (TPR) of the corresponding phosphates. The same materials, Fe2P, CoP and NO, were also prepared on a silica (SiO2) support. The phase purity of these catalysts was established by x-ray diffraction (XRD), and the surface properties were determined by N2 BET specific surface area (Sg) measurements and CO chemisorption. The activities of the silica-supported catalysts were tested in a three-phase trickle bed reactor for the simultaneous hydrodenitrogenation (HDN) of quinoline and hydrodesulfurization (HDS) of dibenzothiophene using a model liquid feed at realistic conditions (30 atm, 370°C). The reactivity studies showed that the nickel phosphide (Ni2P/SiO2) was the most active of the catalysts. Compared with a commercial Ni-Mo-S/gamma-Al 2O3 catalyst at the same conditions, Ni2P/silica had a substantially higher HDS activity (100% vs. 76%) and HDN activity (82% vs. 38%). Because of their good hydrotreating activity, an extensive study of the preparation of silica supported nickel phosphides, Ni2P/SiO 2, was carried out. The parameters investigated were the phosphorus content and the weight loading of the active phase. The most active composition was found to have a starting synthesis Ni/P ratio close to 1/2, and the best loading of this sample on silica was observed to be 18 wt.%. Extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge spectroscopy (XANES) measurements were employed to determine the structures of the supported samples. The main phase before and after reaction was found to be Ni2P, but some sulfur was found to be retained after reaction. A comprehensive scrutiny of the HDN reaction mechanism was also made over the Ni2P/SiO2 sample (Ni/P = 1/2) by comparing the HDN activity of a series of piperidine derivatives of different structure. It was found that piperidine adsorption involved an alpha-H activation and nitrogen removal proceeded mainly by means of a beta-H activation though an elimination (E2) mechanism. The relative elimination rates depended on the type and number of beta-hydrogen atoms. Elimination of beta-H atoms attached to tertiary carbon atoms occurred faster than those attached to secondary carbon atoms. Also, the greater the number of the beta-H atoms, the higher the elimination rates. The nature of the adsorbed intermediates was probed by Fourier transform infrared spectroscopy (FTIR) and temperature-programmed desorption (TPD) of the probe molecule, ethylamine. This measurement allowed the determination of the likely steps in the hydrodenitrogenation reaction.

Laser ablation synthesis of new gold phosphides using red phosphorus and nanogold as precursors. Laser desorption ionisation time-of-flight mass spectrometry.

PubMed

Panyala, Nagender Reddy; Peña-Méndez, Eladia María; Havel, Josef

2012-05-15

Gold phosphides show unique optical or semiconductor properties and there are extensive high technology applications, e.g. in laser diodes, etc. In spite of the various AuP structures known, the search for new materials is wide. Laser ablation synthesis is a promising screening and synthetic method. Generation of gold phosphides via laser ablation of red phosphorus and nanogold mixtures was studied using laser desorption ionisation time-of-flight mass spectrometry (LDI TOFMS). Gold clusters Au(m)(+) (m = 1 to ~35) were observed with a difference of one gold atom and their intensities were in decreasing order with respect to m. For P(n)(+) (n = 2 to ~111) clusters, the intensities of odd-numbered phosphorus clusters are much higher than those for even-numbered phosphorus clusters. During ablation of P-nanogold mixtures, clusters Au(m)(+) (m = 1-12), P(n)(+) (n = 2-7, 9, 11, 13-33, 35-95 (odd numbers)), AuP(n)(+) (n = 1, 2-88 (even numbers)), Au(2)P(n)(+) (n = 1-7, 14-16, 21-51 (odd numbers)), Au(3)P(n)(+) (n = 1-6, 8, 9, 14), Au(4)P(n)(+) (n = 1-9, 14-16), Au(5)P(n)(+) (n = 1-6, 14, 16), Au(6)P(n)(+) (n = 1-6), Au(7)P(n)(+) (n = 1-7), Au(8)P(n)(+) (n = 1-6, 8), Au(9)P(n)(+) (n = 1-10), Au(10)P(n)(+) (n = 1-8, 15), Au(11)P(n)(+) (n = 1-6), and Au(12)P(n)(+) (n = 1, 2, 4) were detected in positive ion mode. In negative ion mode, Au(m)(-) (m = 1-5), P(n)(-) (n = 2, 3, 5-11, 13-19, 21-35, 39, 41, 47, 49, 55 (odd numbers)), AuP(n)(-) (n = 4-6, 8-26, 30-36 (even numbers), 48), Au(2)P(n)(-) (n = 2-5, 8, 11, 13, 15, 17), A(3) P(n)(-) (n = 6-11, 32), Au(4)P(n)(-) (n = 1, 2, 4, 6, 10), Au(6)P(5)(-), and Au(7)P(8)(-) clusters were observed. In both modes, phosphorus-rich Au(m)P(n) clusters prevailed. The first experimental evidence for formation of AuP(60) and gold-covered phosphorus Au(12)P(n) (n = 1, 2, 4) clusters is given. The new gold phosphides generated might inspire synthesis of new Au-P materials with specific properties. Copyright © 2012 John Wiley & Sons, Ltd.

Optical Computing, 1991, Technical Digest Series, Vol. 6

DTIC Science & Technology

1992-05-22

lasers). Compound semiconductors may satisfy these requirements. For example, optical signal amplification by two-beam coupling and amplified phase... compound semiconductors can provide this type of implementationi. This paper presents results from a detailed investigation on potentials of the...conductivity to achieve high multichannel cell performance. We describe several high performance Gallium Phosphide multichannel Bragg cells which employ these

Effects of two prairie dog rodenticides on ground-dwelling invertebrates in western South Dakota

Treesearch

Michele S. Deisch; Daniel W. Uresk; Raymond L. Linder

1989-01-01

Immediate and long-term effects of 3 rodenticide treatments on nontarget invertebrates were evaluated on prairie dog colonies. Immediate impacts indicated zinc phosphide reduced ants, strychnine alone reduced wolf spiders, and prebaited strychnine had no impacts. Long-term changes showed increases in wolf spiders and ground beetles and densities were contributed to...

Petrology and Geochemistry of Lunar Regolith Particle 65903,16-7: Evidence for Extreme Reduction and Oxidation

NASA Technical Reports Server (NTRS)

Zeigler, R. A.; Jolliff, B. L.; Korotev, R. L.; Kremser, D. T.; Haskin, L. A.

2001-01-01

Apollo 16 particle 65903,16-7 is a magnesian, alkali-rich impact melt breccia. Low Fe/Mn and high phosphide/phosphate ratios are evidence of severe reduction during impact-melt cooling. Presence of carbonate and FeOOH is evidence for later oxidation. Additional information is contained in the original extended abstract.

Sarah Kurtz | NREL

Science.gov Websites

next stage of growth for the PV industry. Participated in the demonstration of the GaInP/GaAs solar photovoltaics (PV), concentrator PV, and PV reliability. Kurtz and NREL colleague Jerry Olson championed the early use of multi-junction solar cells by showing that a top cell of gallium indium phosphide (GaInP

40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

Code of Federal Regulations, 2013 CFR

2013-07-01

... Constituent CAS No. Concentration limits (mg/L) Antimony 7440-36-0 1xE+00 Arsenic 7440-38-2 5xE+00 Barium 7440... alcohol 107-18-6 2xE−01 Aluminum phosphide 20859-73-8 1xE−02 Aniline 62-53-3 6xE−02 Barium cyanide 542-62...

Semiconductor devices for optical communications in 1 micron band of wavelength. [gallium indium arsenide phosphide lasers and diodes

NASA Technical Reports Server (NTRS)

Suematsu, Y.; Iga, K.

1980-01-01

Crystal growth and the characteristics of semiconductor lasers and diodes for the long wavelength band used in optical communications are examined. It is concluded that to utilize the advantages of this band, it is necessary to have a large scale multiple wavelength communication, along with optical cumulative circuits and optical exchangers.

Occupational phosphine gas poisoning at veterinary hospitals from dogs that ingested zinc phosphide--Michigan, Iowa, and Washington, 2006-2011.

PubMed

2012-04-27

Zinc phosphide (Zn3P2) is a readily available rodenticide that, on contact with stomach acid and water, produces phosphine (PH3), a highly toxic gas. Household pets that ingest Zn3P2 often will regurgitate, releasing PH3 into the air. Veterinary hospital staff members treating such animals can be poisoned from PH3 exposure. During 2006-2011, CDC's National Institute for Occupational Safety and Health (NIOSH) received reports of PH3 poisonings at four different veterinary hospitals: two in Michigan, one in Iowa, and one in Washington. Each of the four veterinary hospitals had treated a dog that ingested Zn3P2. Among hospital workers, eight poisoning victims were identified, all of whom experienced transient symptoms related to PH3 inhalation. All four dogs recovered fully. Exposure of veterinary staff members to PH3 can be minimized by following phosphine product precautions developed by the American Veterinary Medical Association (AVMA). Exposure of pets, pet owners, and veterinary staff members to PH3 can be minimized by proper storage, handling, and use of Zn3P2 and by using alternative methods for gopher and mole control, such as snap traps.

Submillimeter sources for radiometry using high power Indium Phosphide Gunn diode oscillators

NASA Technical Reports Server (NTRS)

Deo, Naresh C.

1990-01-01

A study aimed at developing high frequency millimeter wave and submillimeter wave local oscillator sources in the 60-600 GHz range was conducted. Sources involved both fundamental and harmonic-extraction type Indium Phosphide Gunn diode oscillators as well as varactor multipliers. In particular, a high power balanced-doubler using varactor diodes was developed for 166 GHz. It is capable of handling 100 mW input power, and typically produced 25 mW output power. A high frequency tripler operating at 500 GHz output frequency was also developed and cascaded with the balanced-doubler. A dual-diode InP Gunn diode combiner was used to pump this cascaded multiplier to produce on the order of 0.5 mW at 500 GHz. In addition, considerable development and characterization work on InP Gunn diode oscillators was carried out. Design data and operating characteristics were documented for a very wide range of oscillators. The reliability of InP devices was examined, and packaging techniques to enhance the performance were analyzed. A theoretical study of a new class of high power multipliers was conducted for future applications. The sources developed here find many commercial applications for radio astronomy and remote sensing.

Electronic Structures of Free-Standing Nanowires made from Indirect Bandgap Semiconductor Gallium Phosphide

PubMed Central

Liao, Gaohua; Luo, Ning; Chen, Ke-Qiu; Xu, H. Q.

2016-01-01

We present a theoretical study of the electronic structures of freestanding nanowires made from gallium phosphide (GaP)—a III-V semiconductor with an indirect bulk bandgap. We consider [001]-oriented GaP nanowires with square and rectangular cross sections, and [111]-oriented GaP nanowires with hexagonal cross sections. Based on tight binding models, both the band structures and wave functions of the nanowires are calculated. For the [001]-oriented GaP nanowires, the bands show anti-crossing structures, while the bands of the [111]-oriented nanowires display crossing structures. Two minima are observed in the conduction bands, while the maximum of the valence bands is always at the Γ-point. Using double group theory, we analyze the symmetry properties of the lowest conduction band states and highest valence band states of GaP nanowires with different sizes and directions. The band state wave functions of the lowest conduction bands and the highest valence bands of the nanowires are evaluated by spatial probability distributions. For practical use, we fit the confinement energies of the electrons and holes in the nanowires to obtain an empirical formula. PMID:27307081

The achievement of low contact resistance to indium phosphide: The roles of Ni, Au, Ge, and combinations thereof

NASA Technical Reports Server (NTRS)

Fatemi, Navid S.; Weizer, Victor G.

1992-01-01

We have investigated the electrical and metallurgical behavior of Ni, Au-Ni, and Au-Ge-Ni contacts on n-InP. We have found that very low values of contact resistivity rho(sub c) in the E-7 omega-sq cm range are obtained with Ni-only contacts. We show that the addition of Au to Ni contact metallization effects an additional order of magnitude reduction in rho(sub c). Ultra-low contact resistivities in the E-8 omega-sq cm range are obtained with both the Au-Ni and the Au-Ge-Ni systems, effectively eliminating the need for the presence of Ge in the Au-Ge-Ni system. The formation of various nickel phosphides at the metal-InP interface is shown to be responsible for the observed rho(sub c) values in the Ni and Au-Ni systems. We show, finally, that the order in which the constituents of Au-Ni and Au-Ge-Ni contacts are deposited has a significant bearing on the composition of the reaction products formed at the metal-InP interface and therefore on the contact resistivity at that interface.

Selective gas adsorption and I-V response of monolayer boron phosphide introduced by dopants: A first-principle study

NASA Astrophysics Data System (ADS)

Cheng, Yongfa; Meng, Ruishen; Tan, Chunjian; Chen, Xianping; Xiao, Jing

2018-01-01

Two-dimensional (2D) materials have gained tremendous research interests for gas sensing applications because of their ultrahigh theoretical specific surface areas and unique electronic properties. Here, we investigate the adsorption of CO, SO2, NH3, O2, NO and NO2 gas molecules on pure and doped boron phosphide (BP) systems using first-principles calculations to exploit their potential in gas sensing. Our results predict that all six gas molecules show stronger adsorption interactions on impurities-doped BP over the pristine monolayer BP. Al-doped BP shows the highest sensitivity to all gas molecules, but N-doped BP is more suitable as a sensing material for SO2, NO and NO2 due to the feasibility of desorption. We further calculated the current-voltage (I-V) relation by mean of nonequilibrium Green's function (NEGF) formalism. The I-V curves indicate that the electronic properties of the doping systems change significantly with gas adsorption by studying the nonparamagnetic molecules NH3 and the paramagnetic molecules NO, which can be more likely to be measured experimentally compared to graphene and phosphorene. This work explores the possibility of BP as a superior sensor through introducing the appropriate dopants.

Superconductivity theory applied to the periodic table of the elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elifritz, T.L.

1994-12-31

The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition, is applied to the periodic table of the elements, in order to isolate the essential features of high temperature superconductivity and to predict its occurrence within the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.

Europe/Latin America Report, Science and Technology

DTIC Science & Technology

1997-01-16

Space Accord 3 AUTOMOBILE INDUSTRY Volvo Chief Attacks Japanese Car Manufacturers’ Tactics in Sweden (SVENSKA DAGBLADET, 21 Nov 86) 4...Great Britain (BIOTEC, Apr 86) 10 EEC’s 1982-86 Biotechnology Programs (BIOTEC, Apr 86) 11 - a Industry , Universities Meet in Italy on...Epitaxy Devices (S. Dumontet; ELECTRONIQUE ACTUALITES, 19 Sep 86) 23 Briefs French Indium Phosphide Production 25 SCIENTIFIC AND INDUSTRIAL POLICY

Sustainable Phosphorus Chemistry: A Silylphosphide Synthon for the Generation of Value-Added Phosphorus Chemicals.

PubMed

Slootweg, J Chris

2018-05-07

Avoiding white phosphorus: Cummins and Geeson have recently described the conversion of phosphoric acid into the novel bis(trichlorosilyl)phosphide anion, which serves as a key intermediate in the synthesis of organophosphines, hexafluorophosphate, and phosphine gas in a reaction sequence that does not rely on white phosphorus. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantum Enhanced Imaging by Entangled States

DTIC Science & Technology

2009-07-01

classes of entangled states. In tripartite systems two classes of genuine tripartite entanglement have been discovered, namely, the Greenberger -Horne...D. M. Greenberger , M. Horne and A. Zeilinger, in Bell’s Theorem, Quantum Theory, and Concepts of the Universe, ed. M. Kafatos (Kluwer, Dordrecht 1989...Gallium Indium Arsenide Phosphide (a III-V compound semiconductor) GHZ: Greenberger -Horne-Zeilinger (a class of entangled states) GLAD: General

Measuring the Dispersion in Laser Cavity Mirrors using White-Light Interferometry

DTIC Science & Technology

2008-03-01

mirrors. Two AlGaInP (aluminum gallium indium phosphide ) diode lasers are aligned such that one is polarized vertically while one is polarized...linear crystals, where the index of refraction depends on beam intensity. Short pulses with high peak intensities are well 14 suited to induce the...MEASURING THE DISPERSION OF LASER CAVITY MIRRORS USING WHITE-LIGHT INTERFEROMETRY THESIS Allison S

Strongly luminescent InP/ZnS core-shell nanoparticles.

PubMed

Haubold, S; Haase, M; Kornowski, A; Weller, H

2001-05-18

The wide-bandgap semiconducting material, zinc sulfide, has been coated on indium phosphide nanoclusters to a 1-2-Å thickness. The resulting InP-ZnS core-shell particle (as shown in the TEM image; scale 1 cm=5 nm) exhibits bright luminescence at room temperature with quantum efficiencies as high as 23 %. © 2001 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

Studies of high temperature ternary phases in mixed-metal-rich early transition metal sulfide and phosphide systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marking, Gregory Allen

1994-01-04

Investigations of ternary mixed early transition metal-rich sulfide and phosphide systems resulted in the discovery of new structures and new phases. A new series of Zr and Hf - group V transition metal - sulfur K-phases was synthesized and crystallographically characterized. When the group V transition metal was Nb or Ta, the unit cell volume was larger than any previously reported K-phase. The presence of adventitious oxygen was determined in two K-phases through a combination of neutron scattering and X-ray diffraction experiments. A compound Hf 10Ta 3S 3 was found to crystallize in a new-structure type similar to the knownmore » gamma brasses. This structure is unique in that it is the only reported "stuffed" gamma-brass type structure. The metal components, Hf and Ta, are larger in size and more electropositive than the metals found in normal gamma brasses (e.g. Cu and Zn) and because of the larger metallic radii, sulfur can be incorporated into the structure where it plays an integral role in stabilizing this phase relative to others. X-ray single-crystal, X-ray powder and neutron powder refinements were performed on this structure. A new structure was found in the ternary Nb-Zr-P system which has characteristics in common with many known early transition metal-rich sulfides, selenides, and phosphides. This structure has the simplest known interconnection of the basic building blocks known for this structural class. Anomalous scattering was a powerful tool for differentiating between Zr and Nb when using Mo Kα X-radiation. The compounds ZrNbP and HfNbP formed in the space group Prima with the simple Co 2Si structure which is among the most common structures found for crystalline solid materials. Solid solution compounds in the Ta-Nb-P, Ta-Zr-P, Nb-Zr-P, Hf-Nb-P, and Hf-Zr-S systems were crystallographically characterized. The structural information corroborated ideas about bonding in metal-rich compounds.« less

Andreyivanovite: A Second New Phosphide from the Kaidun Meteorite

NASA Technical Reports Server (NTRS)

Zolensky, Michael

2008-01-01

Andreyivanovite (ideally FeCrP) is another new phosphide species from the Kaidun meteorite, which fell in South Yemen in 1980. Kaidun is a unique breccia containing an unprecedented variety of fragments of different chondritic as well as achondritic lithologies. Andreyivanovite was found as individual grains and linear arrays of grains with a maximum dimension of 8 m within two masses of Fe-rich serpentine. In one sample it is associated with Fe-Ni-Cr sulfides and florenskyite (FeTiP). Andreyivanovite is creamy white in reflected light, and its luster is metallic. The average of nine electron microprobe analyses yielded the formula Fe(Cr0.587 Fe0.150 V0.109 Ti0.081 Ni0.060 Co0.002)P. Examination of single grains of andreyivanovite using Laue patterns collected by in-situ synchrotron X-ray diffraction (XRD), and by electron backscattered diffraction revealed that it is isostructural with florenskyite; we were unable to find single crystals of sufficient quality to perform a complete structure analysis. Andreyivanovite crystallizes in the space group Pnma, and has the anti-PbCl2 structure. Previously-determined cell constants of synthetic material [a = 5.833(1), b = 3.569(1), c = 6.658(1) A] were consistent with our XRD work. We used the XPOW program to calculate a powder XRD pattern; the 5 most intense reflections are d = 2.247 (I = 100), 2.074 (81), 2.258 (46), 1.785 (43), and 1.885 A (34). Andreyivanovite is the second new phosphide to be described from the Kaidun meteorite. Andreyivanovite could have formed as a result of cooling and crystallization of a melted precursor consisting mainly of Fe-Ni metal enriched in P, Ti, and Cr. Serpentine associated with andreyivanovite would then have formed during aqueous alteration on the parent asteroid. It is also possible that the andreyivanovite could have formed during aqueous alteration, however, artificial FeTiP has been synthesized only during melting experiments, at low oxygen fugacity, and there is no evidence that a hydrothermal genesis is reasonable.

Monodispersed Carbon-Coated Cubic NiP2 Nanoparticles Anchored on Carbon Nanotubes as Ultra-Long-Life Anodes for Reversible Lithium Storage.

PubMed

Lou, Peili; Cui, Zhonghui; Jia, Zhiqing; Sun, Jiyang; Tan, Yingbin; Guo, Xiangxin

2017-04-25

In search of new electrode materials for lithium-ion batteries, metal phosphides that exhibit desirable properties such as high theoretical capacity, moderate discharge plateau, and relatively low polarization recently have attracted a great deal of attention as anode materials. However, the large volume changes and thus resulting collapse of electrode structure during long-term cycling are still challenges for metal-phosphide-based anodes. Here we report an electrode design strategy to solve these problems. The key to this strategy is to confine the electroactive nanoparticles into flexible conductive hosts (like carbon materials) and meanwhile maintain a monodispersed nature of the electroactive particles within the hosts. Monodispersed carbon-coated cubic NiP 2 nanoparticles anchored on carbon nanotubes (NiP 2 @C-CNTs) as a proof-of-concept were designed and synthesized. Excellent cyclability (more than 1000 cycles) and capacity retention (high capacities of 816 mAh g -1 after 1200 cycles at 1300 mA g -1 and 654.5 mAh g -1 after 1500 cycles at 5000 mA g -1 ) are characterized, which is among the best performance of the NiP 2 anodes and even most of the phosphide-based anodes reported so far. The impressive performance is attributed to the superior structure stability and the enhanced reaction kinetics incurred by our design. Furthermore, a full cell consisting of a NiP 2 @C-CNTs anode and a LiFePO 4 cathode is investigated. It delivers an average discharge capacity of 827 mAh g -1 based on the mass of the NiP 2 anode and exhibits a capacity retention of 80.7% over 200 cycles, with an average output of ∼2.32 V. As a proof-of-concept, these results demonstrate the effectiveness of our strategy on improving the electrode performance. We believe that this strategy for construction of high-performance anodes can be extended to other phase-transformation-type materials, which suffer a large volume change upon lithium insertion/extraction.

Superconductivity theory applied to the periodic table of the elements

NASA Technical Reports Server (NTRS)

Elifritz, Thomas Lee

1995-01-01

The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition is applied to the periodic table of the elements, in order to isolate the essential features of of high temperature superconductivity and to predict its occurrence with the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.

Free-space coherent optical communication receivers implemented with photorefractive optical beam combiners

NASA Technical Reports Server (NTRS)

Davidson, Frederic M.

1992-01-01

Performance measurements are reported concerning a coherent optical communication receiver that contained an iron doped indium phosphide photorefractive beam combiner, rather than a conventional optical beam splitter. The system obtained a bit error probability of 10(exp -6) at received signal powers corresponding to less than 100 detected photons per bit. The system used phase modulated Nd:YAG laser light at a wavelength of 1.06 microns.

Screening-Engineered Field-Effect Solar Cells

DTIC Science & Technology

2012-01-01

virtually any semiconductor, including the promising but hard-to- dope metal oxides, sulfides, and phosphides.3 Prototype SFPV devices have been...MIS interface. Unfortu- nately, MIS cells, though sporting impressive efficiencies,4−6 typically have short operating lifetimes due to surface state...instability at the MIS interface.7 Methods aimed at direct field- effect “ doping ” of semiconductors, in which the voltage is externally applied to a gate

Crystal growth of device quality GaAs in space

NASA Technical Reports Server (NTRS)

Gatos, H. C.; Lagowski, J.

1980-01-01

The apparatus and techniques used in effort to determine the relationships between crystal growth and electronic properties are described with emphasis on electroepitaxy and melt-grown gallium aresenide crystal. Applications of deep level transient spectroscopy, derivative photocapitance spectroscopy, and SEM-cathodoluminescene in characterizing wide bandgap semiconductors; determining photoionization in MOS, Schottky barriers, and p-n junctions; and for identifying inhomogeneities are examined, as well as the compensation of indium phosphide.

Implications of extraterrestrial material on the origin of life

NASA Astrophysics Data System (ADS)

Pasek, Matthew A.

Meteoritic organic material may provide the best perspective on prebiotic chemistry. Meteorites have also been invoked as a source of prebiotic material. This study suggests a caveat to extraterrestrial organic delivery: that prebiotic meteoritic organics were too dilute to promote prebiotic reactions. However, meteoritic material provides building material for endogenous synthesis of prebiotic molecules, such as by hydrolysis of extraterrestrial organic tars, and corrosion of phosphide minerals.

Development of advanced thermoelectric materials

NASA Technical Reports Server (NTRS)

1984-01-01

The development of an advanced thermoelectric material for radioisotope thermoelectric generator (RTG) applications is reported. A number of materials were explored. The bulk of the effort, however, was devoted to improving silicon germanium alloys by the addition of gallium phosphide, the synthesis and evaluation of lanthanum chrome sulfide and the formulation of various mixtures of lanthanum sulfide and chrome sulfide. It is found that each of these materials exhibits promise as a thermoelectric material.

Bibliography of Soviet Laser Developments. Number 71, May - June 1984.

DTIC Science & Technology

1985-08-01

d * Coumarin *o..*....... .. o... -- e. Phthalimide ...... o..... o. .. ... --- f . Cyanine .. ... .o o . .. .. .. see. --- go Xanthene...Barinova, E.Yu. (MGU). Determining the concentration of nitrogen in gallium phosphide from its photoluminescence spectrum. VMUFA, no. 3, 1984, 59-62. 23...characteristics for lasing in solutions of rhodamine 6G in a small-base resonator. OPSPA, v.56, no.5, 1984, 884-888. 5 a’ F, c. Polymethine d. Coumarin e

A Mechanistic Study of CO 2 Reduction at the Interface of a Gallium Phosphide (GaP) Surface using Core-level Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flynn, Kristen

2015-08-18

Carbon dioxide (CO 2) emission into the atmosphere has increased tremendously through burning of fossil fuels, forestry, etc.. The increased concentration has made CO 2 reductions very attractive though the reaction is considered uphill. Utilizing the sun as a potential energy source, CO 2 has the possibility to undergo six electron and four proton transfers to produce methanol, a useable resource. This reaction has been shown to occur selectively in an aqueous pyridinium solution with a gallium phosphide (GaP) electrode. Though this reaction has a high faradaic efficiency, it was unclear as to what role the GaP surface played duringmore » the reaction. In this work, we aim to address the fundamental role of GaP during the catalytic conversion, by investigating the interaction between a clean GaP surface with the reactants, products, and intermediates of this reaction using X-ray photoelectron spectroscopy. We have determined a procedure to prepare atomically clean GaP and our initial CO 2 adsorption studies have shown that there is evidence of chemisorption and reaction to form carbonate on the clean surface at LN2 temperatures (80K), in contrast to previous theoretical calculations. These findings will enable future studies on CO 2 catalysis.« less

A Mechanistic Study of CO 2 Reduction at the Interface of a Gallium Phosphide (GaP) Surface using Core-level Spectroscopy - Oral Presentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flynn, Kristen

2015-08-19

Carbon dioxide (CO 2) emission into the atmosphere has increased tremendously through burning of fossil fuels, forestry, etc.. The increased concentration has made CO 2 reductions very attractive though the reaction is considered uphill. Utilizing the sun as a potential energy source, CO 2 has the possibility to undergo six electron and four proton transfers to produce methanol, a useable resource. This reaction has been shown to occur selectively in an aqueous pyridinium solution with a gallium phosphide (GaP) electrode. Though this reaction has a high faradaic efficiency, it was unclear as to what role the GaP surface played duringmore » the reaction. In this work, we aim to address the fundamental role of GaP during the catalytic conversion, by investigating the interaction between a clean GaP surface with the reactants, products, and intermediates of this reaction using X-ray photoelectron spectroscopy. We have determined a procedure to prepare atomically clean GaP and our initial CO 2 adsorption studies have shown that there is evidence of chemisorption and reaction to form carbonate on the clean surface at LN2 temperatures (80K), in contrast to previous theoretical calculations. These findings will enable future studies on CO 2 catalysis.« less

Direct Band Gap Gallium Antimony Phosphide (GaSbxP1−x) Alloys

PubMed Central

Russell, H. B.; Andriotis, A. N.; Menon, M.; Jasinski, J. B.; Martinez-Garcia, A.; Sunkara, M. K.

2016-01-01

Here, we report direct band gap transition for Gallium Phosphide (GaP) when alloyed with just 1–2 at% antimony (Sb) utilizing both density functional theory based computations and experiments. First principles density functional theory calculations of GaSbxP1−x alloys in a 216 atom supercell configuration indicate that an indirect to direct band gap transition occurs at x = 0.0092 or higher Sb incorporation into GaSbxP1−x. Furthermore, these calculations indicate band edge straddling of the hydrogen evolution and oxygen evolution reactions for compositions ranging from x = 0.0092 Sb up to at least x = 0.065 Sb making it a candidate for use in a Schottky type photoelectrochemical water splitting device. GaSbxP1−x nanowires were synthesized by reactive transport utilizing a microwave plasma discharge with average compositions ranging from x = 0.06 to x = 0.12 Sb and direct band gaps between 2.21 eV and 1.33 eV. Photoelectrochemical experiments show that the material is photoactive with p-type conductivity. This study brings attention to a relatively uninvestigated, tunable band gap semiconductor system with tremendous potential in many fields. PMID:26860470

Conceptual design of a lunar base solar power plant lunar base systems study task 3.3

NASA Technical Reports Server (NTRS)

1988-01-01

The best available concepts for a 100 kW Solar Lunar Power Plant based on static and dynamic conversion concepts have been examined. The two concepts which emerged for direct comparison yielded a difference in delivered mass of 35 MT, the mass equivalent of 1.4 lander payloads, in favor of the static concept. The technologies considered for the various elements are either state-of-the-art or near-term. Two photovoltaic cell concepts should receive high priority for development: i.e., amorphous silicon and indium phosphide cells. The amorphous silicon, because it can be made so light weight and rugged; and the indium phosphide, because it shows very high efficiency potential and is reportedly not degraded by radiation. Also the amorphous silicon cells may be mounted on flexible backing that may roll up much like a carpet for compact storage, delivery, and ease of deployment at the base. The fuel cell and electrolysis cell technology is quite well along for lunar base applications, and because both the Shuttle and the forthcoming Space Station incorporate these devices, the status quo will be maintained. Early development of emerging improvements should be implemented so that essential life verification test programs may commence.

Experimental discovery of a topological Weyl semimetal state in TaP

DOE PAGES

Xu, Su -Yang; Belopolski, Ilya; Sanchez, Daniel S.; ...

2015-11-13

Here, Weyl semimetals are expected to open up new horizons in physics and materials science because they provide the first realization of Weyl fermions and exhibit protected Fermi arc surface states. However, they had been found to be extremely rare in nature. Recently, a family of compounds, consisting of tantalum arsenide, tantalum phosphide (TaP), niobium arsenide, and niobium phosphide, was predicted as a Weyl semimetal candidates. We experimentally realize a Weyl semimetal state in TaP. Using photoemission spectroscopy, we directly observe the Weyl fermion cones and nodes in the bulk, and the Fermi arcs on the surface. Moreover, we findmore » that the surface states show an unexpectedly rich structure, including both topological Fermi arcs and several topologically trivial closed contours in the vicinity of the Weyl points, which provides a promising platform to study the interplay between topological and trivial surface states on a Weyl semimetal’s surface. We directly demonstrate the bulk-boundary correspondence and establish the topologically nontrivial nature of the Weyl semimetal state in TaP, by resolving the net number of chiral edge modes on a closed path that encloses the Weyl node. This also provides, for the first time, an experimentally practical approach to demonstrating a bulk Weyl fermion from a surface state dispersion measured in photoemission.« less

Investigation of 2D photonic crystal structure based channel drop filter using quad shaped photonic crystal ring resonator for CWDM system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chhipa, Mayur Kumar, E-mail: mayurchhipa1@gmail.com; Dusad, Lalit Kumar; Rajasthan Technical University, Kota, Rajasthan

In this paper, the design & performance of two dimensional (2-D) photonic crystal structure based channel drop filter is investigated using quad shaped photonic crystal ring resonator. In this paper, Photonic Crystal (PhC) based on square lattice periodic arrays of Gallium Indium Phosphide (GaInP) rods in air structure have been investigated using Finite Difference Time Domain (FDTD) method and photonic band gap is being calculated using Plane Wave Expansion (PWE) method. The PhC designs have been optimized for telecommunication wavelength λ= 1571 nm by varying the rods lattice constant. The number of rods in Z and X directions is 21 andmore » 20, with lattice constant 0.540 nm it illustrates that the arrangement of Gallium Indium Phosphide (GaInP) rods in the structure which gives the overall size of the device around 11.4 µm × 10.8 µm. The designed filter gives good dropping efficiency using 3.298, refractive index. The designed structure is useful for CWDM systems. This device may serve as a key component in photonic integrated circuits. The device is ultra compact with the overall size around 123 µm{sup 2}.« less

General Strategy for the Synthesis of Transition-Metal Phosphide/N-Doped Carbon Frameworks for Hydrogen and Oxygen Evolution.

PubMed

Pu, Zonghua; Zhang, Chengtian; Amiinu, Ibrahim Saana; Li, Wenqiang; Wu, Lin; Mu, Shichun

2017-05-17

Transition metal phosphides (TMPs) have been identified as promising nonprecious metal electrocatalyst for hydrogen evolution reaction (HER) and other energy conversion reactions. Herein, we reported a general strategy for synthesis of a series of TMPs (Fe 2 P, FeP, Co 2 P, CoP, Ni 2 P, and Ni 12 P 5 ) nanoparticles (NPs) with different metal phases embedded in a N-doped carbon (NC) matrix using metal salt, ammonium dihydrogen phosphate, and melamine as precursor with varying molar ratios and thermolysis temperatures. The resultant TMPs can serve as highly active and durable bifunctional electrocatalyst toward HER and oxygen evolution reaction (OER). In particular, the Ni 2 P@NC phase only requires an overpotential of ∼138 mV to derive HER in 0.5 M H 2 SO 4, and ∼320 mV for OER in 1.0 M KOH at the current density of 10 mA cm -2 . Because of the encapsulation of NC that can effectively prevent corrosion of embedded TMP NPs, Ni 2 P@NC exhibits almost unfading catalytic performance even after 10 h under both acidic and alkaline solutions. This synthesis strategy provides a new avenue to exploring TMPs as highly active and stable electrocatalyst for the HER, OER, and other electrochemical applications.

Highly Efficient and Robust Nickel Phosphides as Bifunctional Electrocatalysts for Overall Water-Splitting.

PubMed

Li, Jiayuan; Li, Jing; Zhou, Xuemei; Xia, Zhaoming; Gao, Wei; Ma, Yuanyuan; Qu, Yongquan

2016-05-04

To search for the efficient non-noble metal based and/or earth-abundant electrocatalysts for overall water-splitting is critical to promote the clean-energy technologies for hydrogen economy. Herein, we report nickel phosphide (NixPy) catalysts with the controllable phases as the efficient bifunctional catalysts for water electrolysis. The phases of NixPy were determined by the temperatures of the solid-phase reaction between the ultrathin Ni(OH)2 plates and NaH2PO2·H2O. The NixPy with the richest Ni5P4 phase synthesized at 325 °C (NixPy-325) delivered efficient and robust catalytic performance for hydrogen evolution reaction (HER) in the electrolytes with a wide pH range. The NixPy-325 catalysts also exhibited a remarkable performance for oxygen evolution reaction (OER) in a strong alkaline electrolyte (1.0 M KOH) due to the formation of surface NiOOH species. Furthermore, the bifunctional NixPy-325 catalysts enabled a highly performed overall water-splitting with ∼100% Faradaic efficiency in 1.0 M KOH electrolyte, in which a low applied external potential of 1.57 V led to a stabilized catalytic current density of 10 mA/cm(2) over 60 h.

Assembly of phosphide nanocrystals into porous networks: formation of InP gels and aerogels.

PubMed

Hitihami-Mudiyanselage, Asha; Senevirathne, Keerthi; Brock, Stephanie L

2013-02-26

The applicability of sol-gel nanoparticle assembly routes, previously employed for metal chalcogenides, to phosphides is reported for the case of InP. Two different sizes (3.5 and 6.0 nm) of InP nanoparticles were synthesized by solution-phase arrested precipitation, capped with thiolate ligands, and oxidized with H₂O₂ or O₂/light to induce gel formation. The gels were aged, solvent-exchanged, and then supercritically dried to obtain aerogels with both meso- (2-50 nm) and macropores (>50 nm) and accessible surface areas of ∼200 m²/g. Aerogels showed higher band gap values relative to precursor nanoparticles, suggesting that during the process of assembling nanoparticles into 3D architectures, particle size reduction may have taken place. In contrast to metal chalcogenide gelation, InP gels did not form using tetranitromethane, a non-oxygen-transferring oxidant. The requirement of an oxygen-transferring oxidant, combined with X-ray photoelectron spectroscopy data showing oxidized phosphorus, suggests gelation is occurring due to condensation of phosphorus oxoanionic moieties generated at the interfaces. The ability to link discrete InP nanoparticles into a 3D porous network while maintaining quantum confinement is expected to facilitate exploitation of nanostructured InP in solid-state devices.

Petrography of the carbonaceous, diamond-bearing stone "Hypatia" from southwest Egypt: A contribution to the debate on its origin

NASA Astrophysics Data System (ADS)

Belyanin, Georgy A.; Kramers, Jan D.; Andreoli, Marco A. G.; Greco, Francesco; Gucsik, Arnold; Makhubela, Tebogo V.; Przybylowicz, Wojciech J.; Wiedenbeck, Michael

2018-02-01

The stone named "Hypatia" found in the Libyan Desert Glass area of southwest Egypt is carbon-dominated and rich in microdiamonds. Previous noble gas and nitrogen isotope studies suggest an extraterrestrial origin. We report on a reconnaissance study of the carbonaceous matrix of this stone and the phases enclosed in it. This focused on areas not affected by numerous transecting fractures mostly filled with secondary minerals. The work employed scanning electron microscopy (SEM) with energy-dispersive (EDS) and wavelength-dispersive (WDS) electron microprobe (EMPA) analysis, Proton Induced X-ray Emission (PIXE) spectrometry and micro-Raman spectroscopy. We found that carbonaceous matrices of two types occur irregularly intermingled on the 50-500 μm scale: Matrix-1, consisting of almost pure carbonaceous matter, and Matrix-2, containing Fe, Ni, P and S at abundances analyzable by microprobe. Matrix-2 contains the following phases as inclusions: (i) (Fe,Ni) sulphide occurring in cloud-like concentrations of sub-μm grains, in domains of the matrix that are enriched in Fe and S. These domains have (Fe + Ni)/S (atomic) = 1.51 ± 0.24 and Ni/Fe = 0.086 ± 0.061 (both 1SD); (ii) grains up to ∼5 μm in size of moissanite (SiC); (iii) Ni-phosphide compound grains up to 60 μm across that appear cryptocrystalline or amorphous and have (Ni + Fe)/P (atomic) = 5.6. ± 1.7 and Ni/Fe = 74 ± 29 (both 1SD), where both these ratios are much higher than any known Ni-phosphide minerals; (iv) rare grains (observed only once) of graphite, metallic Al, Fe and Ag, and a phase consisting of Ag, P and I. In Matrix-2, Raman spectroscopy shows a prominent narrow diamond band at 1340 cm-1. In Matrix-1 the D and G bands of disordered carbon are dominant, but a minor diamond band is ubiquitous, accounting for the uniform hardness of the material. The D and G bands have average full width at half maximum (FWHM) values of 295 ± 19 and 115 ± 19 cm-1, respectively, and the D/G intensity ratio is 0.75 ± 0.09 (both 1SD). These values are similar to those of the most primitive solar system carbonaceous matter. The diamond phase is considered to be a product of shock. The (Fe, Ni) sulphide phase is probably pyrrhotite and a shock origin is likewise proposed for it. Moissanite is frequently associated with the Ni-phosphide phase, and a presolar origin for both is suggested. The lack of recrystallization of the Ni-phosphide phase suggests that the Hypatia stone did not experience long-lasting thermal metamorphism, in accord with the Raman D-G band characteristics. A lack of silicate matter sets the stone apart from interplanetary dust particles and known cometary material. This, along with the dual intermingled matrices internal to it, could indicate a high degree of heterogeneity in the early solar nebula.

Humidity-induced room-temperature decomposition of Au contacted indium phosphide

NASA Technical Reports Server (NTRS)

Fatemi, Navid S.; Weizer, Victor G.

1990-01-01

It has been found that Au-contacted InP is chemically unstable at room temperature in a humid ambient due to the leaching action of indium nitrate islands that continually remove In from the contact metallization and thus, in effect, from the Inp substrate. While similar appearing islands form on Au-contacted GaAs, that system appears to be stable since leaching of the group III element does not take place.

Opto-EM and Devices Investigation

DTIC Science & Technology

1989-06-01

value of bandwidth is used the signal to noise ratio of the UAM system becomes ( SNP )u z exp ’cr. 2P,\\ 3 .V N._ W/ 3.3 GAUSSIAN SHAPED MESSAGE SPECTRA...Unclassified N/A 2a. SECURITY CLASSIFICATION AUTHORITY 3 . DISTRIBUTION/AVAILABILITY OF REPORT N/A Approved for public release; 2b. DECLASSIFICATION...Synthesis, Single Crystal Growth, Purification and Characterization of Indium Phosphide 2. Deposition of Select Silicides Under High Vacuum Conditions 3 . Use

Pulsed Plasma Preparation for LWIR Materials

DTIC Science & Technology

1990-06-18

Reported Data: AlP is normally considered chemically unstable with respect to hydrolysis and formation of PH3 as a result of the exceptional stability of...A1203 (and consequently it is often used as a fumigant ). Its stability is thought to increase with purity. The thermal conductivity of crystalline...AlP is high (-1.3 Wcm’Kŕ at room temperature). Experimental Data: Initial films of aluminium phosphide, deposited from trimethylaluminium (TMA) and PH3

Low-Resistivity Zinc Selenide for Heterojunctions

NASA Technical Reports Server (NTRS)

Stirn, R. J.

1986-01-01

Magnetron reactive sputtering enables doping of this semiconductor. Proposed method of reactive sputtering combined with doping shows potential for yielding low-resistivity zinc selenide films. Zinc selenide attractive material for forming heterojunctions with other semiconductor compounds as zinc phosphide, cadmium telluride, and gallium arsenide. Semiconductor junctions promising for future optoelectronic devices, including solar cells and electroluminescent displays. Resistivities of zinc selenide layers deposited by evaporation or chemical vapor deposition too high to form practical heterojunctions.

Microwave Semiconductor Research-Materials, Devices and Circuits.

DTIC Science & Technology

1987-10-01

Quantum Well and Graded Refractive Index Separate Confinement Heterostructure Quantum Well Lasers Grown Via Molecular Beam Epitaxy" JSEP PUBLICATIONS...J.M. Ballantyne and A.J. Sievers, J. Appl. Phys., 58, 3145 (1985). 6. "Epitaxial Growth and Characterization of Indian Phosphide and Gallium Indian...Approach to Dispersion Analysis in Graded Index Optical Fiber", by H.J. Carlin and Henry Zmuda. DEGREES 1. Henry Zmuda, Ph.D., July 1984 "A New Approach

A review of indium phosphide space solar cell fabrication technology

NASA Technical Reports Server (NTRS)

Spitzer, M. B.; Dingle, B.; Dingle, J.; Morrison, R.

1990-01-01

A review of the status of InP cell efficiency and of approaches to the reduction of cell cost is presented. The use of heteroepitaxial techniques such as InP-on-GaAs and InP-on-Si is discussed along with the use of chemical and mechanical techniques for removal and recovery of the substrate. The efficiency ultimately obtainable with designs made possible by such an approach is calculated.

Investigation of the thermophysical properties of high-melting materials with the aid of a complex of instruments

NASA Technical Reports Server (NTRS)

Bolgar, A. S.; Gordiyenko, S. P.; Guseva, Y. A.; Turchanin, A. G.; Fenochka, B. V.; Fesenko, V. V.

1984-01-01

The evaporation rate, vapor pressure, heats of evaporation reaction (sublimation, dissociation), enthalpy, electrical resistance, heat capacity, emissivity, and heat conductivity of various carbides, borides, sulfides, nitrides, selenides, and phosphides were investigated. A set of high temperature high vacuum devices, calorimeters (designed for operation at 400 to 1300 K and from 1200 K), and mass spectrometers, most of which were specially developed for these studies, is described.

Interaction of coal-derived synthesis gas impurities with solid oxide fuel cell metallic components

NASA Astrophysics Data System (ADS)

Marina, Olga A.; Pederson, Larry R.; Coyle, Christopher A.; Edwards, Danny J.; Chou, Yeong-Shyung; Cramer, Carolyn N.

Oxidation-resistant alloys find use as interconnect materials, heat exchangers, and gas supply tubing in solid oxide fuel cell (SOFC) systems, especially when operated at temperatures below ∼800 °C. If fueled with synthesis gas derived from coal or biomass, such metallic components could be exposed to impurities contained in those fuel sources. In this study, coupons of ferritic stainless steels Crofer 22 APU and SS 441, austenitic nickel-chromium superalloy Inconel 600, and an alumina-forming high nickel alloy alumel were exposed to synthesis gas containing ≤2 ppm phosphorus, arsenic and antimony, and reaction products were tested. Crofer 22 APU coupons coated with a (Mn,Co) 3O 4 protective layer were also evaluated. Phosphorus was found to be the most reactive. On Crofer 22 APU, the (Mn,Cr) 3O 4 passivation layer reacted to form an Mn-P-O product, predicted to be manganese phosphate from thermochemical calculations, and Cr 2O 3. On SS 441, reaction of phosphorus with (Mn,Cr) 3O 4 led to the formation of manganese phosphate as well as an Fe-P product, predicted from thermochemical calculations to be Fe 3P. Minimal interactions with antimony or arsenic in synthesis gas were limited to Fe-Sb and Fe-As solid solution formation. Though not intended for use on the anode side, a (Mn,Co) 3O 4 spinel coating on Crofer 22 APU reacted with phosphorus in synthesis gas to produce products consistent with Mn 3(PO 4) 2 and Co 2P. A thin Cr 2O 3 passivation layer on Inconel 600 did not prevent the formation of nickel phosphides and arsenides and of iron phosphides and arsenides, though no reaction with Cr 2O 3 was apparent. On alumel, an Al 2O 3 passivation layer rich in Ni did not prevent the formation of nickel phosphides, arsenides, and antimonides, though no reaction with Al 2O 3 occurred. This work shows that unprotected metallic components of an SOFC stack and system can provide a sink for P, As and Sb impurities that may be present in fuel gases, and thus complicate experimental studies of impurity interactions with the anode.

Junction characteristics of indium tin oxide/indium phosphide solar cells

NASA Astrophysics Data System (ADS)

Sheldon, P.; Ahrenkiel, R. K.; Hayes, R. E.; Russell, P. E.; Nottenburg, R. N.; Kazmerski, L. L.

Efficient indium tin oxide (ITO)/p-InP solar cells have been fabricated. Typical uncorrected efficiencies range from 9-12 percent at AM1 intensities. It is shown that deposition of ITO causes a semi-insulating layer at the InP surface as determined by C-V measurements. The thickness of this layer is approximately 750 A. We believe that this high resistivity region is due to surface accumulation of Fe at the ITO/InP interface.

Liver histopathology of fatal phosphine poisoning.

PubMed

Saleki, Sepideh; Ardalan, Farid Azmoudeh; Javidan-Nejad, Abdullah

2007-03-02

Two commonly used pesticides in agriculture are phosphides of aluminium and zinc. Both of these metal phosphides act through elaboration of toxic phosphine gas. The poisoning in Iran is mostly oral and suicidal. Phosphine is rapidly absorbed throughout the gastrointestinal tract after ingestion and it is partly carried to the liver by the portal vein. In this study the liver histopathology of fatal poisoning is scrutinized. A descriptive, retrospective study was performed on 38 fatal phosphine poisonings. The slides of liver specimens of the cases were retrieved and studied separately by two pathologists. The poisoning was suicidal in 33 (86.5%) of cases. Portal inflammation was negligible in 37 cases and only in one of the cases, a moderate degree of chronic inflammation accompanied by granuloma formation was observed. Major histopathologic findings were as follows: mild sinusoidal congestion; 12 cases (31.6%), severe sinusoidal congestion; 25 cases (45.8%), central vein congestion; 23 cases (60.5%), centrilobular necrosis; 3 cases (7.9%), hepatocytes nuclear fragmentation; 6 cases (15.8%), sinusoidal clusters of polymorphonuclear leukocytes; 12 cases (31.6%), and mild macrovesicular steatosis; 5 cases (13.2%). Fine isomorphic cytoplasmic vacuoles were observed in 36 cases (94.7%). These vacuoles were distributed uniformly in all hepatic zones in the majority (75%) of cases. This study reveals that the main histopathologic findings of fatal phosphine poisoning in the liver are fine cytoplasmic vacuolization of hepatocytes and sinusoidal congestion.

Observation of three-component fermions in the topological semimetal molybdenum phosphide.

PubMed

Lv, B Q; Feng, Z-L; Xu, Q-N; Gao, X; Ma, J-Z; Kong, L-Y; Richard, P; Huang, Y-B; Strocov, V N; Fang, C; Weng, H-M; Shi, Y-G; Qian, T; Ding, H

2017-06-29

In quantum field theory, Lorentz invariance leads to three types of fermion-Dirac, Weyl and Majorana. Although the existence of Weyl and Majorana fermions as elementary particles in high-energy physics is debated, all three types of fermion have been proposed to exist as low-energy, long-wavelength quasiparticle excitations in condensed-matter systems. The existence of Dirac and Weyl fermions in condensed-matter systems has been confirmed experimentally, and that of Majorana fermions is supported by various experiments. However, in condensed-matter systems, fermions in crystals are constrained by the symmetries of the 230 crystal space groups rather than by Lorentz invariance, giving rise to the possibility of finding other types of fermionic excitation that have no counterparts in high-energy physics. Here we use angle-resolved photoemission spectroscopy to demonstrate the existence of a triply degenerate point in the electronic structure of crystalline molybdenum phosphide. Quasiparticle excitations near a triply degenerate point are three-component fermions, beyond the conventional Dirac-Weyl-Majorana classification, which attributes Dirac and Weyl fermions to four- and two-fold degenerate points, respectively. We also observe pairs of Weyl points in the bulk electronic structure of the crystal that coexist with the three-component fermions. This material thus represents a platform for studying the interplay between different types of fermions. Our experimental discovery opens up a way of exploring the new physics of unconventional fermions in condensed-matter systems.

Observation of three-component fermions in the topological semimetal molybdenum phosphide

NASA Astrophysics Data System (ADS)

Lv, B. Q.; Feng, Z.-L.; Xu, Q.-N.; Gao, X.; Ma, J.-Z.; Kong, L.-Y.; Richard, P.; Huang, Y.-B.; Strocov, V. N.; Fang, C.; Weng, H.-M.; Shi, Y.-G.; Qian, T.; Ding, H.

2017-06-01

In quantum field theory, Lorentz invariance leads to three types of fermion—Dirac, Weyl and Majorana. Although the existence of Weyl and Majorana fermions as elementary particles in high-energy physics is debated, all three types of fermion have been proposed to exist as low-energy, long-wavelength quasiparticle excitations in condensed-matter systems. The existence of Dirac and Weyl fermions in condensed-matter systems has been confirmed experimentally, and that of Majorana fermions is supported by various experiments. However, in condensed-matter systems, fermions in crystals are constrained by the symmetries of the 230 crystal space groups rather than by Lorentz invariance, giving rise to the possibility of finding other types of fermionic excitation that have no counterparts in high-energy physics. Here we use angle-resolved photoemission spectroscopy to demonstrate the existence of a triply degenerate point in the electronic structure of crystalline molybdenum phosphide. Quasiparticle excitations near a triply degenerate point are three-component fermions, beyond the conventional Dirac-Weyl-Majorana classification, which attributes Dirac and Weyl fermions to four- and two-fold degenerate points, respectively. We also observe pairs of Weyl points in the bulk electronic structure of the crystal that coexist with the three-component fermions. This material thus represents a platform for studying the interplay between different types of fermions. Our experimental discovery opens up a way of exploring the new physics of unconventional fermions in condensed-matter systems.

PLEURAL EFFECTS OF INDIUM PHOSPHIDE IN B6C3F1 MICE: NONFIBROUS PARTICULATE INDUCED PLEURAL FIBROSIS

PubMed Central

Kirby, Patrick J.; Shines, Cassandra J.; Taylor, Genie J.; Bousquet, Ronald W.; Price, Herman C.; Everitt, Jeffrey I.; Morgan, Daniel L.

2010-01-01

The mechanism(s) by which chronic inhalation of indium phosphide (InP) particles causes pleural fibrosis is not known. Few studies of InP pleural toxicity have been conducted because of the challenges in conducting particulate inhalation exposures, and because the pleural lesions developed slowly over the 2-year inhalation study. The authors investigated whether InP (1 mg/kg) administered by a single oropharyngeal aspiration would cause pleural fibrosis in male B6C3F1 mice. By 28 days after treatment, protein and lactate dehydrogenase (LDH) were significantly increased in bronchoalveolar lavage fluid (BALF), but were unchanged in pleural lavage fluid (PLF). A pronounced pleural effusion characterized by significant increases in cytokines and a 3.7-fold increase in cell number was detected 28 days after InP treatment. Aspiration of soluble InCl3 caused a similar delayed pleural effusion; however, other soluble metals, insoluble particles, and fibers did not. The effusion caused by InP was accompanied by areas of pleural thickening and inflammation at day 28, and by pleural fibrosis at day 98. Aspiration of InP produced pleural fibrosis that was histologically similar to lesions caused by chronic inhalation exposure, and in a shorter time period. This oropharyngeal aspiration model was used to provide an initial characterization of the progression of pleural lesions caused by InP. PMID:19995279

Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning.

PubMed

Soltani, Motahareh; Shetab-Boushehri, Seyed F; Shetab-Boushehri, Seyed V

2016-08-01

Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

Electrostatically driven resonance energy transfer in "cationic" biocompatible indium phosphide quantum dots.

PubMed

Devatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta; Pillai, Pramod P

2017-05-01

Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnology. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biological applications. We have addressed this challenge by developing a place exchange protocol for the preparation of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent positive charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer ( E ∼ 60%) is observed, under physiological conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimolecular quenching constant along with a linear Stern-Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control experiments prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomolecules.

180-GHz I-Q Second Harmonic Resistive Mixer MMIC

NASA Technical Reports Server (NTRS)

Kangaslahti, Pekka P.; Lai, Richard; Mei, Xiaobing

2010-01-01

An indium phosphide MMIC (monolithic microwave integrated circuit) mixer was developed, processed, and tested in the NGC 35-nm-gate-length HEMT (high electron mobility transistor) process. This innovation is very compact in size and operates with very low LO power. Because it is a resistive mixer, this innovation does not require DC power. This is an enabling technology for the miniature receiver modules for the GeoSTAR instrument, which is the only viable option for the NRC decadal study mission PATH.

Gas Phase Ion-Molecule Chemistry of Carbon, Nitrogen and Oxygen Compounds.

DTIC Science & Technology

1985-01-29

silyl anions aza allyl anion) phosphide anion sulfides) Reactivity; nitrite estersj electron affinityMechanism’, sulfur dioxidej. (cont’d) M L..J A6*rAcr...use of silane chemistry to attack a problem of fundamental importance to all organic chemistry, the relative acidity of the alkanes.20 While it is well...alkane lost are a measure of the relative acidity of RH. For example, because ethane is lost less easily than methane, we believe that the ethyl anion

Space Photovoltaic Research and Technology, 1989

NASA Technical Reports Server (NTRS)

1991-01-01

Remarkable progress on a wide variety of approaches in space photovoltaics, for both near and far term applications is reported. Papers were presented in a variety of technical areas, including multi-junction cell technology, GaAs and InP cells, system studies, cell and array development, and non-solar direct conversion. Five workshops were held to discuss the following topics: mechanical versus monolithic multi-junction cells; strategy in space flight experiments; non-solar direct conversion; indium phosphide cells; and space cell theory and modeling.

Cobalt-Doped Nickel Phosphite for High Performance of Electrochemical Energy Storage.

PubMed

Li, Bing; Shi, Yuxin; Huang, Kesheng; Zhao, Mingming; Qiu, Jiaqing; Xue, Huaiguo; Pang, Huan

2018-03-01

Compared to single metallic Ni or Co phosphides, bimetallic Ni-Co phosphides own ameliorative properties, such as high electrical conductivity, remarkable rate capability, upper specific capacity, and excellent cycle performance. Here, a simple one-step solvothermal process is proposed for the synthesis of bouquet-like cobalt-doped nickel phosphite (Ni 11 (HPO 3 ) 8 (OH) 6 ), and the effect of the structure on the pseudocapacitive performance is investigated via a series of electrochemical measurements. It is found that when the cobalt content is low, the glycol/deionized water ratio is 1, and the reaction is under 200 °C for 20 h, the morphology of the sample is uniform and has the highest specific surface area. The cobalt-doped Ni 11 (HPO 3 ) 8 (OH) 6 electrode presents a maximum specific capacitance of 714.8 F g -1 . More significantly, aqueous and solid-state flexible electrochemical energy storage devices are successfully assembled. The aqueous device shows a high energy density of 15.48 mWh cm -2 at the power density of 0.6 KW cm -2 . The solid-state device shows a high energy density of 14.72 mWh cm -2 at the power density of 0.6 KW cm -2 . These excellent performances confirm that the cobalt-doped Ni 11 (HPO 3 ) 8 (OH) 6 are promising materials for applications in electrochemical energy storage devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation of Characteristics and Predictive Factors Affecting Mortality from Aluminum Phosphide Poisoning, Iran.

PubMed

Navabi, Seyed Mohammad Navabi; Navabi, Seyed Jafar; Aghaei, Abbas; Shaahmadi, Zahra; Heydari, Ruhollah

2018-05-27

Aluminum phosphide (ALP) or rice tablet is one of the most effective rodenticides used for the protection of grain storages from animals and rodents. ALP poisoning annually leads to mortality in human beings. The aim of this study was to evaluate the characteristics and predictive factors affecting mortality from ALP poisoning. This study evaluated patients with ALP poisoning referred to Imam Khomeini hospital in Kermanshah from 2014 to 2015. There are several data gathered from patient such as age, sex, number of consumed tablets, the number of attempts to commit suicide, elapsed time from consuming till treatment, blood pressure, PH, HCO3 and PCO2. Survivors (recovery) and non-survivors (death) from ALP poisoning are also evaluated in this study. Univariate logistic regression and multivariate analysis have been applied for data analysis. In this study, 48 patients were male and 29 patients were female, respectively (total 77 patient). The average age of survivors and non-survivors were 28.69 and 31.34 years, respectively. All cases (100%) of ALP poisoning were tried to commit suicide. The results showed that the main predictive variables of mortality from ALP poisoning were blood pressure, PH and elapsed time from consuming till treatment. The prognosis of death for patients with ALP poisoning can be determined by awareness of some of the main characteristics or factors such as blood pressure, PH and elapsed time from consuming till treatment. This can give a possibility for healthcare groups to consider more measures in patients with ALP poisoning.

An electrocardiographic, molecular and biochemical approach to explore the cardioprotective effect of vasopressin and milrinone against phosphide toxicity in rats.

PubMed

Jafari, Abbas; Baghaei, Amir; Solgi, Reza; Baeeri, Maryam; Chamanara, Mohsen; Hassani, Shokoufeh; Gholami, Mahdi; Ostad, Seyed Nasser; Sharifzadeh, Moahmmad; Abdollahi, Mohammad

2015-06-01

The present study was conducted to identify the protective effect of vasopressin (AVP) and milrinone on cardiovascular function, mitochondrial complex activities, cellular ATP reserve, oxidative stress, and apoptosis in rats poisoned by aluminum phosphide (AlP). Rats were divided into five groups (n = 12) including control, AlP (12.5 mg/kg), AlP + AVP (2.0 Units/kg), AlP + milrinone (0.25 mg/kg) and AlP + AVP + milrinone. After treatment, the animals were connected to an electronic cardiovascular monitoring device to monitor electrocardiographic (ECG) parameter. Finally, oxidative stress biomarkers, mitochondrial complex activities, ADP/ATP ratio and apoptosis were evaluated on the heart tissues. Results indicated that AlP administration induced ECG abnormalities along with a decline in blood pressure and heart rate. AVP and milrinone significantly ameliorated these changes in all treated groups. Considerable protective effects on oxidative stress biomarkers, complex IV activity, ADP/ATP ratio and caspase-3 and -9 activities in treated groups were also found. These findings were supported by flow cytometry assay of cardiomyocytes. In conclusion, administration of AVP and milrinone, not only improve cardiovascular functions in AlP poisoned rats in the short time, but after a long time can also restore mitochondrial function and ATP level and reduce the oxidative damage, which prevent cardiomyocytes from entering the apoptotic phase. Copyright © 2015 Elsevier Ltd. All rights reserved.

Acute pesticide poisoning related deaths in Tehran during the period 2003-2004.

PubMed

Soltaninejad, Kambiz; Faryadi, Mansoor; Sardari, Fariba

2007-08-01

Acute pesticide poisoning is an important cause of morbidity and mortality in Iran and worldwide. Determination of inducing factors in pesticide poisoning is very important parameter for planning of preventive and controlling programs. The aim of present study is assessing of effects of epidemiological variables on fatal pesticide poisoning. Data was obtained from autopsies on suspected pesticide poisoning deaths were performed in the Tehran Legal Medicine Center between 2003 and 2004. Among these medicolegal autopsies, fatal poisoning cases were evaluated retrospectively by reports of toxicological analysis. The variables such as age, sex, job, residential location, educational level, type of pesticide and cause of poisoning were reviewed. From total of 3885 autopsies referred to forensic toxicology laboratory for pesticide toxicology analysis, 51 (1.31%) deaths were due to pesticide poisoning. The age of cases was 32+/-17 years old. 63.3% of cases were male and 36.7% of them were female. The majority of cases (31.4%) were housekeeper and 23.5% were student. 66.7% of cases were lived in urban and 33.3% were lived in rural area. The most common type of poisoning was suicide (52.9%). 33.3% of cases had primary education. The common type of pesticide in this study was aluminum phosphide 18 (35.8%) and organophosphates 17 (33.3%). According to fatal aluminum phosphide poisoning, more stringent legislation and enforcement regarding the sale and distribution of this toxic substance is needed. Thus substitution of this pesticide with safer agents is necessary.

Porous Structured Ni–Fe–P Nanocubes Derived from a Prussian Blue Analogue as an Electrocatalyst for Efficient Overall Water Splitting

DOE PAGES

Xuan, Cuijuan; Wang, Jie; Xia, Weiwei; ...

2017-07-18

Exploring nonprecious metal electrocatalysts to replace the noble metal-based catalysts for full water electrocatalysis is still an ongoing challenge. In this work, porous structured ternary nickel–iron–phosphide (Ni–Fe–P) nanocubes were synthesized through one-step phosphidation of a Ni–Fe-based Prussian blue analogue. The Ni–Fe–P nanocubes exhibit a rough and loose porous structure on their surface under suitable phosphating temperature, which is favorable for the mass transfer and oxygen diffusion during the electrocatalysis process. As a result, Ni–Fe–P obtained at 350 °C with poorer crystallinity offers more unsaturated atoms as active sites to expedite the absorption of reactants. Additionally, the introduction of nickel improvedmore » the electronic structure and then reduced the charge-transfer resistance, which would result in a faster electron transport and an enhancement of the intrinsic electrocatalytic activities. Benefiting from the unique porous nanocubes and the chemical composition, the Ni–Fe–P nanocubes exhibit excellent hydrogen evolution reaction and oxygen evolution reaction activities in alkaline medium, with low overpotentials of 182 and 271 mV for delivering a current density of 10 mA cm–2, respectively. Moreover, the Ni–Fe–P nanocubes show outstanding stability for sustained water splitting in the two-electrode alkaline electrolyzer. Furthermore, this work not only provides a facile approach for designing bifunctional electrocatalysts but also further extends the application of metal–organic frameworks in overall water splitting.« less

Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

PubMed Central

Soltani, Motahareh; Shetab-Boushehri, Seyed F.; Shetab-Boushehri, Seyed V.

2016-01-01

Objectives: Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning. PMID:27606109

Porous Structured Ni–Fe–P Nanocubes Derived from a Prussian Blue Analogue as an Electrocatalyst for Efficient Overall Water Splitting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xuan, Cuijuan; Wang, Jie; Xia, Weiwei

Exploring nonprecious metal electrocatalysts to replace the noble metal-based catalysts for full water electrocatalysis is still an ongoing challenge. In this work, porous structured ternary nickel–iron–phosphide (Ni–Fe–P) nanocubes were synthesized through one-step phosphidation of a Ni–Fe-based Prussian blue analogue. The Ni–Fe–P nanocubes exhibit a rough and loose porous structure on their surface under suitable phosphating temperature, which is favorable for the mass transfer and oxygen diffusion during the electrocatalysis process. As a result, Ni–Fe–P obtained at 350 °C with poorer crystallinity offers more unsaturated atoms as active sites to expedite the absorption of reactants. Additionally, the introduction of nickel improvedmore » the electronic structure and then reduced the charge-transfer resistance, which would result in a faster electron transport and an enhancement of the intrinsic electrocatalytic activities. Benefiting from the unique porous nanocubes and the chemical composition, the Ni–Fe–P nanocubes exhibit excellent hydrogen evolution reaction and oxygen evolution reaction activities in alkaline medium, with low overpotentials of 182 and 271 mV for delivering a current density of 10 mA cm–2, respectively. Moreover, the Ni–Fe–P nanocubes show outstanding stability for sustained water splitting in the two-electrode alkaline electrolyzer. Furthermore, this work not only provides a facile approach for designing bifunctional electrocatalysts but also further extends the application of metal–organic frameworks in overall water splitting.« less

Managing aluminum phosphide poisonings

PubMed Central

Gurjar, Mohan; Baronia, Arvind K; Azim, Afzal; Sharma, Kalpana

2011-01-01

Aluminum phosphide (AlP) is a cheap, effective and commonly used pesticide. However, unfortunately, it is now one of the most common causes of poisoning among agricultural pesticides. It liberates lethal phosphine gas when it comes in contact either with atmospheric moisture or with hydrochloric acid in the stomach. The mechanism of toxicity includes cellular hypoxia due to the effect on mitochondria, inhibition of cytochrome C oxidase and formation of highly reactive hydroxyl radicals. The signs and symptoms are nonspecific and instantaneous. The toxicity of AlP particularly affects the cardiac and vascular tissues, which manifest as profound and refractory hypotension, congestive heart failure and electrocardiographic abnormalities. The diagnosis of AlP usually depends on clinical suspicion or history, but can be made easily by the simple silver nitrate test on gastric content or on breath. Due to no known specific antidote, management remains primarily supportive care. Early arrival, resuscitation, diagnosis, decrease the exposure of poison (by gastric lavage with KMnO4, coconut oil), intensive monitoring and supportive therapy may result in good outcome. Prompt and adequate cardiovascular support is important and core in the management to attain adequate tissue perfusion, oxygenation and physiologic metabolic milieu compatible with life until the tissue poison levels are reduced and spontaneous circulation is restored. In most of the studies, poor prognostic factors were presence of acidosis and shock. The overall outcome improved in the last decade due to better and advanced intensive care management. PMID:21887030

Effect of multilayer structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide.

PubMed

Chen, Xianping; Tan, Chunjian; Yang, Qun; Meng, Ruishen; Liang, Qiuhua; Jiang, Junke; Sun, Xiang; Yang, D Q; Ren, Tianling

2016-06-28

Development of nanoelectronics requires two-dimensional (2D) systems with both direct-bandgap and tunable electronic properties as they act in response to the external electric field (E-field). Here, we present a detailed theoretical investigation to predict the effect of atomic structure, stacking order and external electric field on the electrical properties of few-layer boron-phosphide (BP). We demonstrate that the splitting of bands and bandgap of BP depends on the number of layers and the stacking order. The values for the bandgap show a monotonically decreasing relationship with increasing layer number. We also show that AB-stacking BP has a direct-bandgap, while ABA-stacking BP has an indirect-bandgap when the number of layers n > 2. In addition, for a bilayer and a trilayer, the bandgap increases (decreases) as the electric field increases along the positive direction of the external electric field (E-field) (negative direction). In the case of four-layer BP, the bandgap exhibits a nonlinearly decreasing behavior as the increase in the electric field is independent of the electric field direction. The tunable mechanism of the bandgap can be attributed to a giant Stark effect. Interestingly, the investigation also shows that a semiconductor-to-metal transition may occur for the four-layer case or more layers beyond the critical electric field. Our findings may inspire more efforts in fabricating new nanoelectronics devices based on few-layer BP.

Gallium Phosphide Integrated with Silicon Heterojunction Solar Cells

NASA Astrophysics Data System (ADS)

Zhang, Chaomin

It has been a long-standing goal to epitaxially integrate III-V alloys with Si substrates which can enable low-cost microelectronic and optoelectronic systems. Among the III-V alloys, gallium phosphide (GaP) is a strong candidate, especially for solar cells applications. Gallium phosphide with small lattice mismatch ( 0.4%) to Si enables coherent/pseudomorphic epitaxial growth with little crystalline defect creation. The band offset between Si and GaP suggests that GaP can function as an electron-selective contact, and it has been theoretically shown that GaP/Si integrated solar cells have the potential to overcome the limitations of common a-Si based heterojunction (SHJ) solar cells. Despite the promising potential of GaP/Si heterojunction solar cells, there are two main obstacles to realize high performance photovoltaic devices from this structure. First, the growth of the polar material (GaP) on the non-polar material (Si) is a challenge in how to suppress the formation of structural defects, such as anti-phase domains (APD). Further, it is widely observed that the minority-carrier lifetime of the Si substrates is significantly decreased during epitaxially growth of GaP on Si. In this dissertation, two different GaP growth methods were compared and analyzed, including migration-enhanced epitaxy (MEE) and traditional molecular beam epitaxy (MBE). High quality GaP can be realized on precisely oriented (001) Si substrates by MBE growth, and the investigation of structural defect creation in the GaP/Si epitaxial structures was conducted using high resolution X-ray diffraction (HRXRD) and high resolution transmission electron microscopy (HRTEM). The mechanisms responsible for lifetime degradation were further investigated, and it was found that external fast diffusors are the origin for the degradation. Two practical approaches including the use of both a SiNx diffusion barrier layer and P-diffused layers, to suppress the Si minority-carrier lifetime degradation during GaP epitaxial growth on Si by MBE were proposed. To achieve high performance of GaP/Si solar cells, different GaP/Si structures were designed, fabricated and compared, including GaP as a hetero-emitter, GaP as a heterojunction on the rear side, inserting passivation membrane layers at the GaP/Si interface, and GaP/wet-oxide functioning as a passivation contact. A designed of a-Si free carrier-selective contact MoOx/Si/GaP solar cells demonstrated 14.1% power conversion efficiency.

International Conference on Indium Phosphide and Related Materials (22nd) (IPRM) held on 31 May-4 Jun 2010, at Takamatsu Symbol Tower, Kagawa, Japan

DTIC Science & Technology

2010-08-13

and S. Bollaert ANODE & EPIPHY groups IEMN, UMR CNRS 8520 Villeneuve d’Ascq. France aiirelicn.olivierV/’ed.univ-lillel .IV F. Martin . O...Desplats CEA / LETI Grenoble. France J. Saint- Martin . M. Shi IEF. UMR CNRS 8622 Orsay. France Y. Wang. M.P. Chauvat, P. Rutcrana CIMAP. UMR CNRS 8252...efficiency Network Device Project" which PETRA contracted with New Energy and Industrial Technology Development Organization (NEDO). V. Summary References

Measurement of the Two-photon Absorption Coefficient of Gallium Phosphide (GaP) Using a Dispersion-minimized Sub-10 Femtosecond Z-scan Measurement System

DTIC Science & Technology

2012-09-01

bandwidth of the pulse. Using the standard laboratory and analysis methods of Sheik- Bahae et al., we obtain a two-photon absorption coefficient, β, of...organic thin-film materials deposited on various substrates. 15 6. References 1. Sheik- Bahae , M.; Said, A. A.; Van Stryland, E. W. High...sensitivity, Single-beam n2 Measurements. Optics Letters 1989, 14 (17). 2. Sheik- Bahae , M.; Said, A. A.; Van Stryland, E. W.; Wei, T-H; Hagan, D. J

The Kaidun Meteorite: Where Did It Come From?

NASA Technical Reports Server (NTRS)

Ivanov, Andrei; Zolensky, Michael

2003-01-01

The Kaidun meteorite, which fell on 3.12.1980 at lat. 15 deg N, long. 48.3 deg E, holds a special place in the world meteorite collection. Kaidun is characterized by an unprecedentedly wide variety of meteorite material in its makeup. The high degree of variability in this meteorite s material is evidenced by the richness of its mineral composition - nearly 60 minerals and mineral phases have been identified in Kaidun, including several never before found in nature, such as florenskiite FeTiP, the first known phosphide of a lithophilic element.

Optical and Electrical Characterization of Melt-Grown Bulk Indium Gallium Arsenide and Indium Arsenic Phosphide Alloys

DTIC Science & Technology

2011-03-01

order to find Eg/dT, we like to start with taking second derivatives of the absorption coefficient 53 g E EE t EEe E C dE d t g , 22 2...lower band, Nh) is closely related to the Fermi-Dirac distribution, Tk EE Ef B Fexp1 1 )( . (2.1) Here f(E) is the probability of occupying...47 ., , /)( gg g EEE EEEEA EECe tg (4.3) Here the C and A parameters are constants for a given material, for instance, A is

Influence of Natural Convection and Thermal Radiation Multi-Component Transport in MOCVD Reactors

NASA Technical Reports Server (NTRS)

Lowry, S.; Krishnan, A.; Clark, I.

1999-01-01

The influence of Grashof and Reynolds number in Metal Organic Chemical Vapor (MOCVD) reactors is being investigated under a combined empirical/numerical study. As part of that research, the deposition of Indium Phosphide in an MOCVD reactor is modeled using the computational code CFD-ACE. The model includes the effects of convection, conduction, and radiation as well as multi-component diffusion and multi-step surface/gas phase chemistry. The results of the prediction are compared with experimental data for a commercial reactor and analyzed with respect to the model accuracy.

Method for the preparation of inorganic single crystal and polycrystalline electronic materials

NASA Technical Reports Server (NTRS)

Groves, W. O. (Inventor)

1969-01-01

Large area, semiconductor crystals selected from group 3-5 compounds and alloys are provided for semiconductor device fabrication by the use of a selective etching operation which completely removes the substrate on which the desired crystal was deposited. The substrate, selected from the same group as the single crystal, has a higher solution rate than the epitaxial single crystal which is essentially unaffected by the etching solution. The preparation of gallium phosphide single crystals using a gallium arsenide substrate and a concentrated nitric acid etching solution is described.

Development of high temperature gallium phosphide rectifiers

NASA Technical Reports Server (NTRS)

Craford, M. G.; Keune, D. L.

1972-01-01

Large area high performance, GaP rectifiers were fabricated by means of Zn diffusion into vapor phase epitaxial GaP. Devices with an active area of 0.01 sq cm typically exhibit forward voltages of 3 volts for a bias current of 1 ampere and have reverse breakdown voltages of 300 volts for temperatures from 27 C to 400 C. Typical device reverse saturation current at a reverse bias of 150 volts is less than 10 to the minus 9th power amp at 27 C and less than 0.000050 amp at 400 C.

Photovoltaic options for solar electric propulsion

NASA Technical Reports Server (NTRS)

Stella, Paul M.; Flood, Dennis J.

1990-01-01

This paper discusses both state-of-the-art and advanced development cell and array technology. Present technology includes rigid, roll-out, and foldout flexible substrate designs, with silicon and GaAs solar cells. The use of concentrator array systems is discussed based on both DOD efforts and NASA work. The benefits of advanced lightweight array technology, for both near term and far term utilization, and of advanced high efficiency thin radiation resistant cells is examined. This includes gallium arsenide/germanium, indium phosphide, and thin film devices such as copper indium disclenide.

Static photoelasticity of gallium phosphide crystals

NASA Astrophysics Data System (ADS)

Mytsyk, B. G.; Andrushchak, A. S.; Kost', Ya. P.

2012-01-01

The piezo-optic effect (POE) in cubic GaP crystals (symmetry class bar 43 m) is studied in detail by interferometry. The relations for determining the absolute piezo-optic coefficients (POCs) π im or their combinations on a sample of X/45° cut at all allowable geometries of the experiment are recorded. The determination of a specific coefficient π im at different experimental geometries on samples of right cuts and a X/45° cut made it possible to find the π im values with a high accuracy and reliability.

Advanced power systems for EOS

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Weinberg, Irving; Flood, Dennis J.

1991-01-01

The Earth Observing System, which is part of the International Mission to Planet Earth, is NASA's main contribution to the Global Change Research Program. Five large platforms are to be launched into polar orbit: two by NASA, two by the European Space Agency, and one by the Japanese. In such an orbit the radiation resistance of indium phosphide solar cells combined with the potential of utilizing 5 micron cell structures yields an increase of 10 percent in the payload capability. If further combined with the Advanced Photovoltaic Solar Array, the total additional payload capability approaches 12 percent.

Laboratory trials of seven rodenticides for use against the cotton rat (Sigmodon hispidus).

PubMed Central

Gill, J. E.; Redfern, R.

1980-01-01

The efficacy of seven rodenticides for use against Sigmodon hispidus was investigated in the laboratory. The poisons (warfarin, coumatetralyl, difenacoum, brodifacoum, bromadiolone, calciferol and zinc phosphide) were all toxic at the concentrations normally used against Rattus rattus and R. norvegicus and all were palatable. Trials are now needed to confirm the efficacy of these poisons in the field, but it seems likely that, if used in suitable bait formulations, they would all be useful for the practical control of S. hispidus. PMID:7462594

Experimental control of steady state photorefractive self-focusing in InP:Fe at infrared wavelengths

NASA Astrophysics Data System (ADS)

Dan, C.; Wolfersberger, D.; Fressengeas, N.

2011-09-01

This paper reports an experimental study of the self-focusing process in iron doped indium phosphide at an 1.06 micron wavelength, identifying the influence of temperature, beam intensity and background illumination for two different iron dopings. We point out that the iron ionization ratio is at the origin of different qualitative behavior previously reported and we show that it is possible to reproduce the said behaviors in the same crystal by applying a uniform illumination, allowing their eventual control for dynamic wave-guiding.

Probing near-normally propagating bulk acoustic waves using pseudo-reflection geometry Brillouin spectroscopy

NASA Astrophysics Data System (ADS)

Parsons, L. C.; Andrews, G. T.

2012-09-01

Pseudo-reflection geometry Brillouin spectroscopy can be used to probe acoustic wave dispersion approximately along the surface normal of a material system while avoiding the difficulties associated with specularly reflected light encountered in an ideal reflection configuration. As an example of its application, we show analytically that it can be used to determine both the refractive index and bulk acoustic mode velocities of optically-isotropic non-metallic materials and confirm the utility of the approach via a series of experiments on fused quartz, gallium phosphide, water, and porous silicon films.

Modeling Laser Effects on Multi-Junction Solar Cells Using Silvaco ATLAS Software for Spacecraft Power Beaming Applications

DTIC Science & Technology

2010-06-01

could not. Figure 11 shows the Indium Gallium Phosphide (InGaP)- Gallium Arsenide (GaAs)- Germanium (Ge) solar cell utilization of the solar spectrum...2 opcv nL  (4.4) p = 1, 2, 3, … nr = index of refraction of the cavity co = speed of light in a vacuum (m/s) L = cavity length (meters...illumination – ηsolar  Efficiency under solar illumination – n Number of electrons – nr Index of refraction –  Photon frequency Hz ΔFSR

99 W mid-IR operation of a ZGP OPO at 25% duty cycle.

PubMed

Hemming, Alexander; Richards, Jim; Davidson, Alan; Carmody, Neil; Bennetts, Shayne; Simakov, Nikita; Haub, John

2013-04-22

We have demonstrated the highest reported output power from a mid-IR ZGP OPO. The laser is a cascaded hybrid system consisting of a thulium fibre laser, Ho:YAG solid state laser and a Zinc Germanium Phosphide parametric oscillator. The system produces 27 W of output power in the 3-5 μm wavelength range with an M(2) = 4.0 when operating in a repetitively q-switched mode, and a modulated peak output power of 99 W at a reduced duty cycle of 25%.

Electrochemical Characterization of InP and GaAs Based Structures for Space Solar Cell Applications.

NASA Technical Reports Server (NTRS)

Faur, Maria; Faur, Mircea; Jenkins, Philip P.; Goradia, Manju; Wilt, David M.

1994-01-01

In this paper the emphasis is on accurate majority carrier concentration EC-V profiling of structures based on Indium Phosphide and Gallium Arsenide, using a newly developed electrolyte based on Hydrogen Flouride, Acetic Acid, Phosphoric Acid, 1-phenyl-2-propanamine and Ammonia Diflouride. Some preliminary data on the use of this electrolyte for determining the energy distribution of surface and deep states of these structures, applicable to fabrication process optimization and radiation induced defects studies of solar cells, are also provided.

CVD growth and properties of boron phosphide on 3C-SiC

NASA Astrophysics Data System (ADS)

Padavala, Balabalaji; Frye, C. D.; Wang, Xuejing; Raghothamachar, Balaji; Edgar, J. H.

2016-09-01

Improving the crystalline quality of boron phosphide (BP) is essential for realizing its full potential in semiconductor device applications. In this study, 3C-SiC was tested as a substrate for BP epitaxy. BP films were grown on 3C-SiC(100)/Si, 3C-SiC(111)/Si, and 3C-SiC(111)/4H-SiC(0001) substrates in a horizontal chemical vapor deposition (CVD) system. Films were produced with good crystalline orientation and morphological features in the temperature range of 1000-1200 °C using a PH3+B2H6+H2 mixture. Rotational twinning was absent in the BP due to the crystal symmetry-matching with 3C-SiC. Confocal 3D Raman imaging of BP films revealed primarily uniform peak shift and peak widths across the scanned area, except at defects on the surface. Synchrotron white beam X-ray topography showed the epitaxial relationship between BP and 3C-SiC was (100) 〈 011 〉 BP||(100) 〈 011 〉 3C-SiC and (111) 〈 11 2 ̅ 〉 BP||(111) 〈 11 2 ̅ 〉 3C-SiC. Scanning electron microscopy, Raman spectroscopy and X-ray diffraction analysis indicated residual tensile strain in the films and improved crystalline quality at temperatures below 1200 °C. These results indicated that BP properties could be further enhanced by employing high quality bulk 3C-SiC or 3C-SiC epilayers on 4H-SiC substrates.

Atomistic investigations on the mechanical properties and fracture mechanisms of indium phosphide nanowires.

PubMed

Pial, Turash Haque; Rakib, Tawfiqur; Mojumder, Satyajit; Motalab, Mohammad; Akanda, M A Salam

2018-03-28

The mechanical properties of indium phosphide (InP) nanowires are an emerging issue due to the promising applications of these nanowires in nanoelectromechanical and microelectromechanical devices. In this study, molecular dynamics simulations of zincblende (ZB) and wurtzite (WZ) crystal structured InP nanowires (NWs) are presented under uniaxial tension at varying sizes and temperatures. It is observed that the tensile strengths of both types of NWs show inverse relationships with temperature, but are independent of the size of the nanowires. Moreover, applied load causes brittle fracture by nucleating cleavage on ZB and WZ NWs. When the tensile load is applied along the [001] direction, the direction of the cleavage planes of ZB NWs changes with temperature. It is found that the {111} planes are the cleavage planes at lower temperatures; on the other hand, the {110} cleavage planes are activated at elevated temperatures. In the case of WZ NWs, fracture of the material is observed to occur by cleaving along the (0001) plane irrespective of temperature when the tensile load is applied along the [0001] direction. Furthermore, the WZ NWs of InP show considerably higher strength than their ZB counterparts. Finally, the impact of strain rate on the failure behavior of InP NWs is also studied, and higher fracture strengths and strains at higher strain rates are found. With increasing strain rate, the number of cleavages also increases in the NWs. This paper also provides in-depth understanding of the failure behavior of InP NWs, which will aid the design of efficient InP NWs-based devices.

High efficiency GaP power conversion for Betavoltaic applications

NASA Astrophysics Data System (ADS)

Sims, Paul E.; Dinetta, Louis C.; Barnett, Allen M.

1994-09-01

AstroPower is developing a gallium phosphide (GaP) based energy converter optimized for radio luminescent light-based power supplies. A 'two-step' or 'indirect' process is used where a phosphor is excited by radioactive decay products to produce light that is then converted to electricity by a photovoltaic energy converter. This indirect conversion of beta-radiation to electrical energy can be realized by applying recent developments in tritium based radio luminescent (RL) light sources in combination with the high conversion efficiencies that can be achieved under low illumination with low leakage, gallium phosphide based devices. This tritium to light approach is inherently safer than battery designs that incorporate high activity radionuclides because the beta particles emitted by tritium are of low average energy and are easily stopped by a thin layer of glass. GaP layers were grown by liquid phase epitaxy and p/n junction devices were fabricated and characterized for low light intensity power conversion. AstroPower has demonstrated the feasibility of the GaP based energy converter with the following key results: 23.54 percent conversion efficiency under 968 muW/sq cm 440 nm blue light, 14.59 percent conversion efficiency for 2.85 muW/sq cm 440 nm blue light, and fabrication of working 5 V array. We have also determined that at least 20 muW/sq cm optical power is available for betavoltaic power systems. Successful developments of this device is an enabling technology for low volume, safe, high voltage, milliwatt power supplies with service lifetimes in excess of 12 years.

Indium Phosphide Window Layers for Indium Gallium Arsenide Solar Cells

NASA Technical Reports Server (NTRS)

Jain, Raj K.

2005-01-01

Window layers help in reducing the surface recombination at the emitter surface of the solar cells resulting in significant improvement in energy conversion efficiency. Indium gallium arsenide (In(x)Ga(1-x)As) and related materials based solar cells are quite promising for photovoltaic and thermophotovoltaic applications. The flexibility of the change in the bandgap energy and the growth of InGaAs on different substrates make this material very attractive for multi-bandgap energy, multi-junction solar cell approaches. The high efficiency and better radiation performance of the solar cell structures based on InGaAs make them suitable for space power applications. This work investigates the suitability of indium phosphide (InP) window layers for lattice-matched In(0.53)Ga(0.47)As (bandgap energy 0.74 eV) solar cells. We present the first data on the effects of the p-type InP window layer on p-on-n lattice-matched InGaAs solar cells. The modeled quantum efficiency results show a significant improvement in the blue region with the InP window. The bare InGaAs solar cell performance suffers due to high surface recombination velocity (10(exp 7) cm/s). The large band discontinuity at the InP/InGaAs heterojunction offers a great potential barrier to minority carriers. The calculated results demonstrate that the InP window layer effectively passivates the solar cell front surface, hence resulting in reduced surface recombination and therefore, significantly improving the performance of the InGaAs solar cell.

Strain-Compensated InGaAsP Superlattices for Defect Reduction of InP Grown on Exact-Oriented (001) Patterned Si Substrates by Metal Organic Chemical Vapor Deposition.

PubMed

Megalini, Ludovico; Šuran Brunelli, Simone Tommaso; Charles, William O; Taylor, Aidan; Isaac, Brandon; Bowers, John E; Klamkin, Jonathan

2018-02-26

We report on the use of InGaAsP strain-compensated superlattices (SC-SLs) as a technique to reduce the defect density of Indium Phosphide (InP) grown on silicon (InP-on-Si) by Metal Organic Chemical Vapor Deposition (MOCVD). Initially, a 2 μm thick gallium arsenide (GaAs) layer was grown with very high uniformity on exact oriented (001) 300 mm Si wafers; which had been patterned in 90 nm V-grooved trenches separated by silicon dioxide (SiO₂) stripes and oriented along the [110] direction. Undercut at the Si/SiO₂ interface was used to reduce the propagation of defects into the III-V layers. Following wafer dicing; 2.6 μm of indium phosphide (InP) was grown on such GaAs-on-Si templates. InGaAsP SC-SLs and thermal annealing were used to achieve a high-quality and smooth InP pseudo-substrate with a reduced defect density. Both the GaAs-on-Si and the subsequently grown InP layers were characterized using a variety of techniques including X-ray diffraction (XRD); atomic force microscopy (AFM); transmission electron microscopy (TEM); and electron channeling contrast imaging (ECCI); which indicate high-quality of the epitaxial films. The threading dislocation density and RMS surface roughness of the final InP layer were 5 × 10⁸/cm² and 1.2 nm; respectively and 7.8 × 10⁷/cm² and 10.8 nm for the GaAs-on-Si layer.

[Health risks from pest control products].

PubMed

Pieper, C; Holthenrich, D; Schneider, H

2014-05-01

According to European biocide legislation, pest control products require assessment and authorization by the responsible national or European authorities. Biocidal products can only be authorized if they have no unacceptable effects on human health. The health risk assessment performed for authorization comprises (a) the derivation of reference values for the active substances and substances of concern contained in the biocidal product and (b) an exposure assessment. These parameters are required for risk characterization. No unacceptable health risks are expected if the determined exposure is less than the relevant reference value. In addition, the toxicological information is used for classification of the biocidal product. The assessment may, where necessary, result in specific conditions for use or other restrictions aimed at minimizing risk. The risk to human health from pest control products is mainly based on the toxicological properties of their active substances. Commonly, the coformulants used in pest control products are of less concern than the active substances (e.g., food ingredients and animal feed products). For example, most rodenticides belong to the group of anticoagulants, which are also effective in humans. Regarding intoxications through insecticides, the group of pyrethroids is of particular importance. Fumigants containing metal phosphides, hydrogen cyanide, or sulfuryl difluoride are particularly toxic. This toxicity is linked to the high acute inhalation toxicity of the gaseous active substances themselves or, in the case of phosphides, of the released gas phosphane. The aim of health risk assessment for the authorization of biocidal products is to ensure their safe application for users and all other persons involved, assuming an adequate and label-compliant use.

Indium phosphide all air-gap Fabry-Pérot filters for near-infrared spectroscopic applications

NASA Astrophysics Data System (ADS)

Ullah, A.; Butt, M. A.; Fomchenkov, S. A.; Khonina, S. N.

2016-08-01

Food quality can be characterized by noninvasive techniques such as spectroscopy in the Near Infrared wavelength range. For example, 930 -1450 nm wavelength range can be used to detect diseases and differentiate between meat samples. Miniaturization of such NIR spectrometers is useful for quick and mobile characterization of food samples. Spectrometers can be miniaturized, without compromising the spectral resolution, using Fabry-Pérot (FP) filters consisting of two highly reflecting mirrors with a central cavity in between. The most commonly used mirrors in the design of FP filters are Distributed Bragg Reflections (DBRs) consisting of alternating high and low refractive index material pairs, due to their high reflectivity compared to metal mirrors. However, DBRs have high reflectivity for a selected range of wavelengths known as the stopband of the DBR. This range is usually much smaller than the sensitivity range of the spectrometer detector. Therefore, a bandpass filter is usually required to restrict wavelengths outside the stopband of the FP DBRs. Such bandpass filters are difficult to design and implement. Alternatively, high index contrast materials must be can be used to broaden the stopband width of the FP DBRs. In this work, Indium phosphide all air-gap filters are proposed in conjunction with InGaAs based detectors. The designed filter has a wide stopband covering the entire InGaAs detector sensitivity range. The filter can be tuned in the 950-1450 nm with single mode operation. The designed filter can hence be used for noninvasive meat quality control.

High efficiency GaP power conversion for Betavoltaic applications

NASA Technical Reports Server (NTRS)

Sims, Paul E.; Dinetta, Louis C.; Barnett, Allen M.

1994-01-01

AstroPower is developing a gallium phosphide (GaP) based energy converter optimized for radio luminescent light-based power supplies. A 'two-step' or 'indirect' process is used where a phosphor is excited by radioactive decay products to produce light that is then converted to electricity by a photovoltaic energy converter. This indirect conversion of beta-radiation to electrical energy can be realized by applying recent developments in tritium based radio luminescent (RL) light sources in combination with the high conversion efficiencies that can be achieved under low illumination with low leakage, gallium phosphide based devices. This tritium to light approach is inherently safer than battery designs that incorporate high activity radionuclides because the beta particles emitted by tritium are of low average energy and are easily stopped by a thin layer of glass. GaP layers were grown by liquid phase epitaxy and p/n junction devices were fabricated and characterized for low light intensity power conversion. AstroPower has demonstrated the feasibility of the GaP based energy converter with the following key results: 23.54 percent conversion efficiency under 968 muW/sq cm 440 nm blue light, 14.59 percent conversion efficiency for 2.85 muW/sq cm 440 nm blue light, and fabrication of working 5 V array. We have also determined that at least 20 muW/sq cm optical power is available for betavoltaic power systems. Successful developments of this device is an enabling technology for low volume, safe, high voltage, milliwatt power supplies with service lifetimes in excess of 12 years.

CVD growth and properties of boron phosphide on 3C-SiC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padavala, Balabalaji; Frye, C. D.; Wang, Xuejing

Improving the crystalline quality of boron phosphide (BP) is essential for realizing its full potential in semiconductor device applications. In this study, 3C-SiC was tested as a substrate for BP epitaxy. BP films were grown on 3C-SiC(100)/Si, 3C-SiC(111)/Si, and 3C-SiC(111)/4H-SiC(0001) substrates in a horizontal chemical vapor deposition (CVD) system. Films were produced with good crystalline orientation and morphological features in the temperature range of 1000–1200 °C using a PH3+B2H6+H2 mixture. Rotational twinning was absent in the BP due to the crystal symmetry-matching with 3C-SiC. Confocal 3D Raman imaging of BP films revealed primarily uniform peak shift and peak widths acrossmore » the scanned area, except at defects on the surface. Synchrotron white beam X-ray topography showed the epitaxial relationship between BP and 3C-SiC was (100) <011>BP||(100) <011>3C-SiC and (111)View the MathML sourceBP||(111)View the MathML source3C-SiC. Scanning electron microscopy, Raman spectroscopy and X-ray diffraction analysis indicated residual tensile strain in the films and improved crystalline quality at temperatures below 1200 °C. These results indicated that BP properties could be further enhanced by employing high quality bulk 3C-SiC or 3C-SiC epilayers on 4H-SiC substrates.« less

Strain-Compensated InGaAsP Superlattices for Defect Reduction of InP Grown on Exact-Oriented (001) Patterned Si Substrates by Metal Organic Chemical Vapor Deposition

PubMed Central

Megalini, Ludovico; Šuran Brunelli, Simone Tommaso; Charles, William O.; Taylor, Aidan; Isaac, Brandon; Klamkin, Jonathan

2018-01-01

We report on the use of InGaAsP strain-compensated superlattices (SC-SLs) as a technique to reduce the defect density of Indium Phosphide (InP) grown on silicon (InP-on-Si) by Metal Organic Chemical Vapor Deposition (MOCVD). Initially, a 2 μm thick gallium arsenide (GaAs) layer was grown with very high uniformity on exact oriented (001) 300 mm Si wafers; which had been patterned in 90 nm V-grooved trenches separated by silicon dioxide (SiO2) stripes and oriented along the [110] direction. Undercut at the Si/SiO2 interface was used to reduce the propagation of defects into the III–V layers. Following wafer dicing; 2.6 μm of indium phosphide (InP) was grown on such GaAs-on-Si templates. InGaAsP SC-SLs and thermal annealing were used to achieve a high-quality and smooth InP pseudo-substrate with a reduced defect density. Both the GaAs-on-Si and the subsequently grown InP layers were characterized using a variety of techniques including X-ray diffraction (XRD); atomic force microscopy (AFM); transmission electron microscopy (TEM); and electron channeling contrast imaging (ECCI); which indicate high-quality of the epitaxial films. The threading dislocation density and RMS surface roughness of the final InP layer were 5 × 108/cm2 and 1.2 nm; respectively and 7.8 × 107/cm2 and 10.8 nm for the GaAs-on-Si layer. PMID:29495381

Nanostructured Semiconductor Electrodes for Solar Energy Conversion and Innovations in Undergraduate Chemical Lab Curriculum

NASA Astrophysics Data System (ADS)

Lee, Sudarat

This dissertation presents the methodology and discussion of preparing nanostructured, high aspect ratio p-type phosphide-based binary and ternary semiconductors via "top-down" anodic etching, a process which creates nanostructures from a large parent entity, and "bottom-up" vapor-liquid-solid growth, a mechanism which builds up small clusters of molecules block-by-block. Such architecture is particularly useful for semiconducting materials with incompatible optical absorption depth and charge carrier diffusion length, as it not only relaxes the requirement for high-grade crystalline materials, but also increases the carrier collection efficiencies for photons with energy greater than or equal to the band gap. The main focus of this dissertation is to obtain nanostructured p-type phosphide semiconductors for photoelectrochemical (PEC) cell applications. Chapter II in the thesis describes a methodology for creating high-aspect ratio p-GaP that function as a photocathode under white light illumination. Gallium phosphide (GaP, band gap: 2.26 eV) is a suitable candidate for solar conversion and energy storage due to its ability to generate large photocurrent and photovoltage to drive fuel-forming reactions. Furthermore, the band edge positions of GaP can provide sufficient kinetics for the reduction of protons and carbon dioxide. The structure is prepared by anodic etching, and the resulting macroporous structures are subsequently doped with Zn by thermally driving in Zn from conformal ZnO films prepared by atomic layer deposition (ALD). The key finding of this work is a viable doping strategy involving ALD ZnO films for making functioning p-type GaP nanostructures. Chapter III compares the GaP nanowires grown from gold (Au) and tin (Sn) VLS catalysts in a benign solid sublimation growth scheme in terms of crystal structure and photoactivity. Sn is less noble than Au, allowing complete removal of Sn metal catalysts from the nanowires through wet chemical etching which found to be useful for subsequent thermal diffusion p-type doping without fear of contaminations like Au. The main finding of this work is Sn-seeded GaP nanowires although Sn was removed without any residues and the nanowires had less twin defects than Au-seeded GaP, the nanowires were degenerately n-doped. On the contrary, Au-seeded GaP nanowires exhibited n-type characteristics with orthogonalized light absorption and charge separation. Chapter IV describes the synthesis of zinc tin phosphide (ZSP), a ternary analog of GaP comprised of low-cost, earth-abundant elements in the nanowire form using Sn nanoparticles as the VLS growth seed. The as-prepared ZSP nanowire film is capable of sustaining stable cathodic photoresponse in aqueous electrolyte under white light illumination. The nanowires were crystalized in the stoichiometric sphalerite form and possessed a direct optical band gap of ˜ 1.5 eV instead of the chalcopyrite structure that has comparable band gap energy to GaP. The Sn nanoparticles acted as the VLS seed as well as Sn source for the ZnSnP 2 nanowires growth. Chapter V summarizes the progress and findings of p-GaP nanowire array films as well as a phase non-specific, persistent ALD dye attachment scheme that facilitates hole injection into p-GaP photocathodes, extending the photon absorption range beyond its band gap. Lastly, a separate work about undergraduate chemical education development is documented in Chapter VI of this thesis. Chapter VI details the efforts made in two distinct undergraduate laboratory coursework with the intention to introduce modern microfluidics and photovoltaic technologies including multidisciplinary research experience to the undergraduate students.

High-Efficiency Thin-Film Silicon-on-GaP Solar Cell for Improved Radiation Resistance.

DTIC Science & Technology

1987-09-01

UNCLASSIFIED MyUM 21 LIX E / 82H M D 132 11111_Lt5l1. t FILE UPI" AD-A190 268 AFWAL-TR-87-2070 HIGH-EFFICIENCY THIN- FILM SILICON-ON-GaP SOLAR CELL...EFFICIENCY THIN- FILM SILICON-ON-GaP SOLAR CELL FOR IMPROVED RADIATION RESISTANCE 12. PERSONAL AUTHOR(S) JEROME S. CULIK 13a. TYPE OF REPORT 13b. TIME...C tinue on reverse if necessary and identify by block number) 10 01 SILICONs THIN* FILM , . HETEROEPITAXIAL, RADIATION, 10 01 i GALLIUM PHOSPHIDE 19

Comparative modeling of InP solar cell structures

NASA Technical Reports Server (NTRS)

Jain, R. K.; Weinberg, I.; Flood, D. J.

1991-01-01

The comparative modeling of p(+)n and n(+)p indium phosphide solar cell structures is studied using a numerical program PC-1D. The optimal design study has predicted that the p(+)n structure offers improved cell efficiencies as compared to n(+)p structure, due to higher open-circuit voltage. The various cell material and process parameters to achieve the maximum cell efficiencies are reported. The effect of some of the cell parameters on InP cell I-V characteristics was studied. The available radiation resistance data on n(+)p and p(+)p InP solar cells are also critically discussed.

Label swapper device for spectral amplitude coded optical packet networks monolithically integrated on InP.

PubMed

Muñoz, P; García-Olcina, R; Habib, C; Chen, L R; Leijtens, X J M; de Vries, T; Robbins, D; Capmany, J

2011-07-04

In this paper the design, fabrication and experimental characterization of an spectral amplitude coded (SAC) optical label swapper monolithically integrated on Indium Phosphide (InP) is presented. The device has a footprint of 4.8x1.5 mm2 and is able to perform label swapping operations required in SAC at a speed of 155 Mbps. The device was manufactured in InP using a multiple purpose generic integration scheme. Compared to previous SAC label swapper demonstrations, using discrete component assembly, this label swapper chip operates two order of magnitudes faster.

International Conference on Indium Phosphide and Related Materials, Held in Cape Cod, Massachusetts, on 11 - 15 May 1997.

DTIC Science & Technology

1998-01-14

runaway cells are very uniform across the wafer. On-wafer active load- causing the so-called current collapse. Using a Au air- pull measurement was...Input Power [ dBm] support and encouragement. References Fig. 4: On-wafer load- pull measurement at 9 GHz. [1] P. M. Asbeck, M. C. F. Chang, J. A...Measured Load Pull Characteristics of the 0.15gm x 300gm GaInAs/InP HEMT at 7GHz. 160 exceeded 830 mS/mm for > 0.5V. The 140 small-signal output

Technology and Application of Indium Phosphide and Related Semiconductors

DTIC Science & Technology

1989-03-01

Application and Insertion, GED-L 80/84-9, Oct 1984 1.2: M. Y. Yen , B. F. Levine, C. G. Bethea, K. K. Choi, and A. Y. Cho, Appl. Phys. Lett. 50 (1987) 927...Schlachetzki, Solid-State Electron. 28 (1985) 299 40 IV,A,5: F. B. Fank, J. D. Crowley, and J. J. Berenz, Microwave Journal, June 1979, p. 86 IV,A.6...Ser. 79 (1986) 703 IV,CIb.6: N. K. Dutta, S. G. Napholtz, R. Yen , R. L. Brown, T. M. Shen, N. A. Olsson, and D. C. Craft, Appl. Phys. Lett. 46 (1985

1/F Noise in Indium Phosphide Transistors

DTIC Science & Technology

1992-04-01

Zn/5 nm Au. The gate length and width were 1 Pm and 400 gm, respectively. The device was annealed at 375"C in argon for 1 minute to simultaneously...evaporation, defined by lift-off, and annealed at 375°C for 10 minutes. The gate region was recessed until a source-drain current of 35 mA was obtained...considerations for the signal Sn V,2/R, at the network input from the amplifier output show that vo2 4RoR,, s - 4 nR 2 = So •Mo. (6) 4Ro (Ro + R,) 2

Indium phosphide solar cell research in the United States: Comparison with non-photovoltaic sources

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1989-01-01

Highlights of the InP solar cell research program are presented. Homojunction cells with efficiencies approaching 19 percent are demonstrated, while 17 percent is achieved for ITO/InP cells. The superior radiation resistance of the two latter cell configurations over both Si and GaAs cells has been shown. InP cells aboard the LIPS3 satellite show no degradation after more than a year in orbit. Computed array specific powers are used to compare the performance of an InP solar cell array to solar dynamic and nuclear systems.

Diffusion length variation and proton damage coefficients for InP/In(x)Ga(1-x)As/GaAs solar cells

NASA Technical Reports Server (NTRS)

Jain, R. K.; Weinberg, I.; Flood, D. J.

1993-01-01

Indium phosphide solar cells are more radiation resistant than gallium arsenide and silicon solar cells, and their growth by heteroepitaxy offers additional advantages leading to the development of lighter, mechanically strong and cost-effective cells. Changes in heteroepitaxial InP cell efficiency under 0.5 and 3 MeV proton irradiations are explained by the variation in the minority-carrier diffusion length. The base diffusion length versus proton fluence is calculated by simulating the cell performance. The diffusion length damage coefficient K(L) is plotted as a function of proton fluence.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jena, Puru; Kandalam, Anil K.; Christian, Theresa M.

Gallium phosphide bismide (GaP1-xBix) epilayers with bismuth fractions from 0.9% to 3.2%, as calculated from lattice parameter measurements, were studied with Rutherford backscattering spectrometry (RBS) to directly measure bismuth incorporation. The total bismuth fractions found by RBS were higher than expected from the lattice parameter calculations. Furthermore, in one analyzed sample grown by molecular beam epitaxy at 300 degrees C, 55% of incorporated bismuth was found to occupy interstitial sites. We discuss implications of this high interstitial incorporation fraction and its possible relationship to x-ray diffraction and photoluminescence measurements of GaP0.99Bi0.01.

The discovery of iron barringerite in lunar meteorite Y-793274

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandstatter, F.; Kurat, G.; Koeberl, C.

1991-04-01

The higher phosphide barringerite, (Fe,Ni){sub 2}P, has been found in a thin section of the Y-793274 lunar meteorite. This meteorite originated from a highlands/mare boundary and contains mare and highlands components in a 2:1 ratio. The original report of barringerite was from the Ollague pallasite; however, there is uncertainty where the barringerite in this pallasite may have formed terrestrially. Terrestrial weathering or artificial heating as the source of the barringerite in the lunar meteorite can be excluded. Therefore, Y-793274 seems to contain the first unambiguous extraterrestrial occurrence of barringerite.

Lightweight porous plastic plaque. [nickel cadmium batteries

NASA Technical Reports Server (NTRS)

Reid, M.

1978-01-01

The porosity and platability of various materials were investigated to determine a suitable substrate for nickel-plated electrodes. Immersion, ultrasonics, and flow-through plating techniques were tried using nonproprietary formulations, and proprietary phosphide and boride baths. Modifications to the selected material include variations in formulation and treatment, carbon loading to increase conductivity, and the incorporation of a grid. Problems to be solved relate to determining conductivities and porosities as a function of amount of nickel plated on the plastics; loading; charge and discharge curves of electrodes at different current densities; cell performance; and long-term degradation of electrodes.

Systems analysis of Mars solar electric propulsion vehicles

NASA Technical Reports Server (NTRS)

Hickman, J. M.; Curtis, H. B.; Kenny, B. H.; Sefcik, R. J.

1990-01-01

Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and energy storage are made. It is determined that atmospheric drag is of no great concern and that the energy storage used in countering drag is unnecessary. A scheme to package the arrays, masts, and ion thrusters into a single fairing is presented.

Microstructure, texture evolution and magnetic properties of strip-casting non-oriented 6.5 wt.% Si electrical steel doped with cerium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hao-Ze, E-mail: lhzqq83@163.com; Liu, Hai-Tao; Liu, Zhen-Yu, E-mail: zyliu@mail.neu.edu.cn

A 0.3 mm thick non-oriented 6.5 wt.% Si electrical steel sheet doped with cerium is produced by twin-roll strip casting, hot rolling, warm rolling and annealing. A detailed study of the cerium precipitates in the as-cast strip, microstructure and texture evolution at different processing stages is carried out by electron probe micro-analysis, optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. Grain interior distributing precipitates identified as Ce-oxides, Ce-oxysulfides and Ce-phosphides, and boundary distributing Ce-oxides and Ce-phosphides are observed in the as-cast strip. The initial as-cast strip is characterized by a much finer solidification microstructure and dominated by obvious //ND texture through the strip thickness. After hot and warm rolling, inhomogeneous microstructure containing large amounts of in-grain shear bands is characterized by mixed < 110 >//RD and < 111 >//ND textures. The texture of the annealed sheet with a relatively large average grain size is far more optimized by the domination of the beneficial cube, rotated cube, (001)< 120 > to (001)< 130 > and Goss texture components, and the elimination of the detrimental γ-fiber texture, leading to a superior magnetic induction and improved iron loss. - Highlights: • An Fe–6.5 wt.% Si as-cast strip doped with cerium was produced. • A thin warm rolled sheet with limited edge cracks was obtained. • Microstructure and texture evolution at each stage were investigated. • Strong λ-fiber and Goss recrystallization textures were formed. • The magnetic properties of the annealed sheet were significantly improved.« less

Byproduct-free mass production of compound semiconductor nanowires: zinc phosphide

NASA Astrophysics Data System (ADS)

Chen, Yixi; Polinnaya, Rakesh; Vaddiraju, Sreeram

2018-05-01

A method for the mass production of compound semiconductor nanowires that involves the direct reaction of component elements in a chemical vapor deposition chamber (CVD) is presented. This method results in nanowires, without the associated production of any other byproducts such as nanoparticles or three-dimensional (3D) bulk crystals. Furthermore, no unreacted reactants remain mixed with the nanowire product in this method. This byproduct-free nanowire production thus circumvents the need to tediously purify and collect nanowires from a mixture of products/reactants after their synthesis. Demonstration made using zinc phosphide (Zn3P2) material system as an example indicated that the direct reaction of zinc microparticles with phosphorus supplied via the vapor phase results in the production of gram quantities of nanowires. To enhance thermal transport and achieve the complete reaction of zinc microparticles, while simultaneously ensuring that the microparticles do not agglomerate into macroscale zinc particles and partly remain unreacted (owing to diffusion limitations), pellets composed of mixtures of zinc and a sacrificial salt, NH4Cl, were employed as the starting material. The sublimation by decomposition of NH4Cl in the early stages of the reaction leaves a highly porous pellet of zinc composed of only zinc microparticles, which allows for inward diffusion of phosphorus/outward diffusion of zinc and the complete conversion of zinc into Zn3P2 nanowires. NH4Cl also aids in removal of any native oxide layer present on the zinc microparticles that may prevent their reaction with phosphorus. This method may be used to mass produce many other nanowires in a byproduct-free manner, besides Zn3P2.

Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna

PubMed Central

Mattsson, Karin; Adolfsson, Karl; Ekvall, Mikael T.; Borgström, Magnus T.; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy; Prinz, Christelle N.

2016-01-01

Abstract Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter. PMID:27181920

Stability of CoP x Electrocatalysts in Continuous and Interrupted Acidic Electrolysis of Water.

PubMed

Goryachev, Andrey; Gao, Lu; Zhang, Yue; Rohling, Roderigh Y; Vervuurt, René H J; Bol, Ageeth A; Hofmann, Jan P; Hensen, Emiel J M

2018-04-11

Cobalt phosphides are an emerging earth-abundant alternative to platinum-group-metal-based electrocatalysts for the hydrogen evolution reaction (HER). Yet, their stability is inferior to platinum and compromises the large-scale applicability of CoP x in water electrolyzers. In the present study, we employed flat, thin CoP x electrodes prepared through the thermal phosphidation (PH 3 ) of Co 3 O 4 films made by plasma-enhanced atomic layer deposition to evaluate their stability in acidic water electrolysis by using a multi-technique approach. The films were found to be composed of two phases: CoP in the bulk and a P-rich surface CoP x (P/Co>1). Their performance was evaluated in the HER and the exchange current density was determined to be j 0 =-8.9 ⋅ 10 -5  A/cm 2 . The apparent activation energy of HER on CoP x ( E a =81±15 kJ/mol) was determined for the first time. Dissolution of the material in 0.5 M H 2 SO 4 was observed, regardless of the constantly applied cathodic potential, pointing towards a chemical instead of an electrochemical origin of the observed cathodic instability. The current density and HER faradaic efficiency (FE) were found to be stable during chronoamperometric treatment, as the chemical composition of the HER-active phase remained unchanged. On the contrary, a dynamic potential change performed in a repeated way facilitated dissolution of the film, yielding its complete degradation within 5 h. There, the FE was also found to be changing. An oxidative route of CoP x dissolution has also been proposed.

Performance characterization of mid-infrared difference frequency generation in orientation-patterned gallium phosphide

NASA Astrophysics Data System (ADS)

Wei, Junxiong; Chaitanya Kumar, S.; Ye, Hanyu; Schunemann, Peter G.; Ebrahim-Zadeh, M.

2018-02-01

Orientation-patterned gallium phosphide (OP-GaP) is a recently developed nonlinear material with wide transparency across 0.8-12 μm and high nonlinearity (d14 70 pm/V), which is a promising candidate material for mid-infrared generation. Here we report the full performance characterization of a tunable single-pass nanosecond difference frequency generation (DFG) source based on OP-GaP by mixing the output of a Q-switched Nd:YAG laser at 1.064 μm with the signal from a pulsed MgO:PPLN OPO pumped by the same laser. Using the longest OP-GaP crystal (40 mm) deployed to date, the DFG source provides up to 14 mW of average output power at 2719 nm at 80 kHz repetition rate, with >6 mW across 2492-2782 nm, in TEM00 spatial profile. By performing relevant measurements, detrimental issues such as residual absorption and thermal effects have been studied and confirmed. The temperature and spectral acceptance bandwidths for DFG in the 40-mm-log OP-GaP are measured to be 18 °C and 17 nm, respectively, at 1766 nm. The DFG beam exhibits passive power stability better than 1.7% rms over 1.4 hours at 2774 nm, compared to 1.6% and 0.1% rms for the signal and pump, respectively. The polarization dependence of the input beams on the DFG power has also been systematically investigated, for the first time to our knowledge. Further, we have measured the damage threshold of the OP-GaP crystal to be 0.8 J/cm2 at 1064 nm.

N-acetylcysteine, Ascorbic Acid, and Methylene Blue for the Treatment of Aluminium Phosphide Poisoning: Still Beneficial?

PubMed Central

Gheshlaghi, Farzad; Lavasanijou, Mohamad Reza; Moghaddam, Noushin Afshar; Khazaei, Majid; Behjati, Mohaddeseh; Farajzadegan, Ziba; Sabzghabaee, Ali Mohammad

2015-01-01

Objectives: Intentional and accidental intoxication with aluminium phosphide (ALP) remains a clinical problem, especially in the Middle East region. Considering the high mortality rate besides lack of any recommended first option drug for its treatment, this study was aimed to compare the therapeutic effects of N-acetylcysteine (NAC), vitamin C (Vit C), and methylene blue; both in isolate and also in combination, for the treatment of ALP intoxication in a rat model. Materials and Methods: In this experimental animal study, 80 male Wistar rats in eight groups were intoxicated with ALP (12.5 mg/kg) and treated with a single dose of NAC (100 mg/kg) or Vit C (500–1,000 mg/kg) or methylene blue (1 mg/kg/5 min, 0.1%) or two of these agents or all three of them (controls were not treated). Rats were monitored regarding the parameters of drug efficacy as increased survival time and reduced morbidity and mortality rate for 3 consecutive days to ensure toxin neutralization. Macroscopic changes were recorded and biopsy sections were taken from brain, cerebellum, kidney, liver, and heart for microscopic evaluation regarding cellular hypoxia. Results: The mean survival times of rats exposed to ALP and treated with VitC + NAC was 210.55±236.22 minutes. In analysis of survival times, there was a significant difference between Group 5 which received VitC + NAC and the other groups (P < 0.01). Serum magnesium levels after death were higher than normal (P = 0.01). Conclusions: Despite the higher survival rate of antioxidant-treated rats compared with controls, this difference was not statistically significant. PMID:26862259

Elevated Carboxyhaemoglobin Concentrations by Pulse CO-Oximetry is Associated with Severe Aluminium Phosphide Poisoning.

PubMed

Mashayekhian, Mohammad; Hassanian-Moghaddam, Hossein; Rahimi, Mitra; Zamani, Nasim; Aghabiklooei, Abbas; Shadnia, Shahin

2016-09-01

In pulse CO-oximetry of aluminium phosphide (ALP)-poisoned patients, we discovered that carboxyhaemoglobin (CO-Hb) level was elevated. We aimed to determine whether a higher CO level was detected in patients with severe ALP poisoning and if this could be used as a prognostic factor in these patients. In a prospective case-control study, 96 suspected cases of ALP poisoning were evaluated. In the ALP-poisoned group, demographic characteristics, gastric and exhalation silver nitrate test results, average CO-Hb saturation, methaemoglobin saturation, and blood pressure and blood gas analysis until death/discharge were recorded. Severely poisoned patients were defined as those with systolic blood pressure ≤80 mmHg, pH ≤7.2, or HCO3 ≤15 meq/L or those who died, while patients with minor poisoning were those without any of these signs/symptoms. A control group (37 patients) was taken from other medically ill patients to detect probable effects of hypotension and metabolic acidosis on CO-Hb and methaemoglobin saturations. Of 96 patients, 27 died and 37 fulfilled the criteria for severe poisoning. All patients with carbon monoxide saturation >18% met the criteria to be included in the severe poisoning group and all with a SpCO >25% died. Concerning all significant variables in univariate analysis of severe ALP toxicity, the only significant variable which could independently predict death was carbon monoxide saturation. Due to high mortality rate and need for intensive care support, early prediction of outcome is vital for choosing an appropriate setting (ICU or ordinary ward). CO-oximetry is a good diagnostic and prognostic factor in patients with ALP poisoning even before any clinical evidence of toxicity will develop. © 2016 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Pushing indium phosphide quantum dot emission deeper into the near infrared

NASA Astrophysics Data System (ADS)

Saeboe, A. M.; Kays, J.; Mahler, A. H.; Dennis, A. M.

2018-02-01

Cadmium-free near infrared (NIR) emitting quantum dots (QDs) have significant potential for multiplexed tissue-depth imaging applications in the first optical tissue window (i.e., 650 - 900 nm). Indium phosphide (InP) chemistry provides one of the more promising cadmium-free options for biomedical imaging, but the full tunability of this material has not yet been achieved. Specifically, InP QD emission has been tuned from 480 - 730 nm in previous literature reports, but examples of samples emitting from 730 nm to the InP bulk bandgap limit of 925 nm are lacking. We hypothesize that by generating inverted structures comprising ZnSe/InP/ZnS in a core/shell/shell heterostructure, optical emission from the InP shell can be tuned by changing the InP shell thickness, including pushing deeper into the NIR than current InP QDs. Colloidal synthesis methods including hot injection precipitation of the ZnSe core and a modified successive ion layer adsorption and reaction (SILAR) method for stepwise shell deposition were used to promote growth of core/shell/shell materials with varying thicknesses of the InP shell. By controlling the number of injections of indium and phosphorous precursor material, the emission peak was tuned from 515 nm to 845 nm (2.41 - 1.47 eV) with consistent full width half maximum (FWHM) values of the emission peak 0.32 eV. To confer water solubility, the nanoparticles were encapsulated in PEGylated phospholipid micelles, and multiplexing of NIR-emitting InP QDs was demonstrated using an IVIS imaging system. These materials show potential for multiplexed imaging of targeted QD contrast agents in the first optical tissue window.

Electrostatically driven resonance energy transfer in “cationic” biocompatible indium phosphide quantum dots† †Electronic supplementary information (ESI) available: Detailed experimental methods, the synthesis and characterization of QDs, bioimaging, stability studies, control experiments, and the calculation of various parameters involved in the resonance energy transfer process etc. See DOI: 10.1039/c7sc00592j Click here for additional data file.

PubMed Central

Devatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta

2017-01-01

Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnology. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biological applications. We have addressed this challenge by developing a place exchange protocol for the preparation of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent positive charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer (E ∼ 60%) is observed, under physiological conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimolecular quenching constant along with a linear Stern–Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control experiments prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomolecules. PMID:28626557

Skutterudite Compounds For Power Semiconductor Devices

NASA Technical Reports Server (NTRS)

Fleurial, Jean-Pierre; Caillat, Thierry; Borshchevsky, Alexander; Vandersande, Jan

1996-01-01

New semiconducting materials with p-type carrier mobility values much higher than state-of-art semiconductors discovered. Nine compounds, antimonides CoSb(sub3), RhSb(sub3), IrSb(sub3), arsenides CoAs(sub3), RhAs(sub3), IrAs(sub3), and phosphides CoP(sub3), RhP(sub3) and IrP(sub3), exhibit same skutterudite crystallographic structure and form solid solutions of general composition Co(1-x-y)RH(x)Ir(y)P(1-w-z)As(w)Sb(z). Materials exhibit high hole mobilities, high doping levels, and high electronic figures of merit. Some compositions show great potential for application to thermoelectric devices.

Solar cells based on InP/GaP/Si structure

NASA Astrophysics Data System (ADS)

Kvitsiani, O.; Laperashvil, D.; Laperashvili, T.; Mikelashvili, V.

2016-10-01

Solar cells (SCs) based on III-V semiconductors are reviewed. Presented work emphases on the Solar Cells containing Quantum Dots (QDs) for next-generation photovoltaics. In this work the method of fabrication of InP QDs on III-V semiconductors is investigated. The original method of electrochemical deposition of metals: indium (In), gallium (Ga) and of alloys (InGa) on the surface of gallium phosphide (GaP), and mechanism of formation of InP QDs on GaP surface is presented. The possibilities of application of InP/GaP/Si structure as SC are discussed, and the challenges arising is also considered.

Metrological-grade tunable coherent source in the mid-infrared for molecular precision spectroscopy

NASA Astrophysics Data System (ADS)

Insero, G.; Clivati, C.; D'Ambrosio, D.; Cancio Pastor, P.; Verde, M.; Schunemann, P. G.; Zondy, J.-J.; Inguscio, M.; Calonico, D.; Levi, F.; De Natale, P.; Santambrogio, G.; Borri, S.

2018-02-01

We report on a metrological-grade mid-IR source with a 10-14 short-term instability for high-precision spectroscopy. Our source is based on the combination of a quantum cascade laser and a coherent radiation obtained by difference-frequency generation in an orientation-patterned gallium phosphide (OP-GaP) crystal. The pump and signal lasers are locked to an optical frequency comb referenced to the primary frequency standard via an optical fiber link. We demonstrate the robustness of the apparatus by measuring a vibrational transition around 6 μm on a metastable state of CO molecuels with 11 digits of precision.

Enhanced EOS photovoltaic power system capability with InP solar cells

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Weinberg, Irving; Flood, Dennis J.

1991-01-01

The Earth Observing System (EOS), which is part of the International Mission to Planet Earth, is NASA's main contribution to the Global Change Research Program which opens a new era in international cooperation to study the Earth's environment. Five large platforms are to be launched into polar orbit, two by NASA, two by ESA, and one by the Japanese. In such an orbit the radiation resistance of indium phosphide solar cells combined with the potential of utilizing five micron cell structures yields an increase of 10 percent in the payload capability. If further combined with the advanced photovoltaic solar array the payload savings approaches 12 percent.

Better Ohmic Contacts For InP Semiconductor Devices

NASA Technical Reports Server (NTRS)

Weizer, Victor G.; Fatemi, Navid S.

1995-01-01

Four design modifications enable fabrication of improved ohmic contacts on InP-based semiconductor devices. First modification consists of insertion of layer of gold phosphide between n-doped InP and metal or other overlayer of contact material. Second, includes first modification plus use of particular metal overlayer to achieve very low contact resistivities. Third, also involves deposition of Au(2)P(3) interlayer; in addition, refractory metal (W or Ta) deposited to form contact overlayer. In fourth, contact layer of Auln alloy deposited directly on InP. Improved contacts exhibit low electrical resistances and fabricated without exposing devices to destructive predeposition or postdeposition treatments.

Carbon phosphide monolayers with superior carrier mobility

NASA Astrophysics Data System (ADS)

Wang, Gaoxue; Pandey, Ravindra; Karna, Shashi P.

2016-04-01

Two dimensional (2D) materials with a finite band gap and high carrier mobility are sought after materials from both fundamental and technological perspectives. In this paper, we present the results based on the particle swarm optimization method and density functional theory which predict three geometrically different phases of the carbon phosphide (CP) monolayer consisting of sp2 hybridized C atoms and sp3 hybridized P atoms in hexagonal networks. Two of the phases, referred to as α-CP and β-CP with puckered or buckled surfaces are semiconducting with highly anisotropic electronic and mechanical properties. More remarkably, they have the lightest electrons and holes among the known 2D semiconductors, yielding superior carrier mobility. The γ-CP has a distorted hexagonal network and exhibits a semi-metallic behavior with Dirac cones. These theoretical findings suggest that the binary CP monolayer is a yet unexplored 2D material holding great promise for applications in high-performance electronics and optoelectronics.Two dimensional (2D) materials with a finite band gap and high carrier mobility are sought after materials from both fundamental and technological perspectives. In this paper, we present the results based on the particle swarm optimization method and density functional theory which predict three geometrically different phases of the carbon phosphide (CP) monolayer consisting of sp2 hybridized C atoms and sp3 hybridized P atoms in hexagonal networks. Two of the phases, referred to as α-CP and β-CP with puckered or buckled surfaces are semiconducting with highly anisotropic electronic and mechanical properties. More remarkably, they have the lightest electrons and holes among the known 2D semiconductors, yielding superior carrier mobility. The γ-CP has a distorted hexagonal network and exhibits a semi-metallic behavior with Dirac cones. These theoretical findings suggest that the binary CP monolayer is a yet unexplored 2D material holding great promise for applications in high-performance electronics and optoelectronics. Electronic supplementary information (ESI) available: Fig. S1 cohesive energy and structure of the CP monolayer with various stoichiometric compositions obtained using CALYPSO, Fig. S2 history of CALYPSO steps and structure of the CP monolayer, Fig. S3 phonon dispersion with DFT-D2 functional, Fig. S4 band structure for β-CP using the DFT-PBE and DFT-D2 functional forms, Fig. S5 strain energy curves, Fig. S6 projected band structure for α-CP, Fig. S7 projected band structure for β-CP, Fig. S8 projected band structure for γ-CP, Fig. S9 band structures obtained with the GGA-PBE and HSE06 functional; Table S1 lattice parameters with the DFT-D2 functional form; Video S1 AIMD simulation of α-CP at 300 K, Video S2 AIMD simulation of β-CP at 300 K, Video S3 AIMD simulation of γ-CP at 300 K. See DOI: 10.1039/c6nr00498a

Advanced Density Functional Theory Methods for Materials Science

NASA Astrophysics Data System (ADS)

Demers, Steven

In this work we chiefly deal with two broad classes of problems in computational materials science, determining the doping mechanism in a semiconductor and developing an extreme condition equation of state. While solving certain aspects of these questions is well-trodden ground, both require extending the reach of existing methods to fully answer them. Here we choose to build upon the framework of density functional theory (DFT) which provides an efficient means to investigate a system from a quantum mechanics description. Zinc Phosphide (Zn3P2) could be the basis for cheap and highly efficient solar cells. Its use in this regard is limited by the difficulty in n-type doping the material. In an effort to understand the mechanism behind this, the energetics and electronic structure of intrinsic point defects in zinc phosphide are studied using generalized Kohn-Sham theory and utilizing the Heyd, Scuseria, and Ernzerhof (HSE) hybrid functional for exchange and correlation. Novel 'perturbation extrapolation' is utilized to extend the use of the computationally expensive HSE functional to this large-scale defect system. According to calculations, the formation energy of charged phosphorus interstitial defects are very low in n-type Zn3P2 and act as 'electron sinks', nullifying the desired doping and lowering the fermi-level back towards the p-type regime. Going forward, this insight provides clues to fabricating useful zinc phosphide based devices. In addition, the methodology developed for this work can be applied to further doping studies in other systems. Accurate determination of high pressure and temperature equations of state is fundamental in a variety of fields. However, it is often very difficult to cover a wide range of temperatures and pressures in an laboratory setting. Here we develop methods to determine a multi-phase equation of state for Ta through computation. The typical means of investigating thermodynamic properties is via 'classical' molecular dynamics where the atomic motion is calculated from Newtonian mechanics with the electronic effects abstracted away into an interatomic potential function. For our purposes, a 'first principles' approach such as DFT is useful as a classical potential is typically valid for only a portion of the phase diagram (i.e. whatever part it has been fit to). Furthermore, for extremes of temperature and pressure quantum effects become critical to accurately capture an equation of state and are very hard to capture in even complex model potentials. This requires extending the inherently zero temperature DFT to predict the finite temperature response of the system. Statistical modelling and thermodynamic integration is used to extend our results over all phases, as well as phase-coexistence regions which are at the limits of typical DFT validity. We deliver the most comprehensive and accurate equation of state that has been done for Ta. This work also lends insights that can be applied to further equation of state work in many other materials.

Clarifying coverages on the basis of tapes SnO2, SiO2, Si3N4 for photodiodes of ultraviolet and visible range

NASA Astrophysics Data System (ADS)

Dobrovolsciy, Yu. George; Perevertaylo, Vladimir L.; Shabashcevich, Boris G.; Pidkamin, Leonid J.

2009-10-01

It is shown, what coverage of dioxide of tin is instrumental in the rise of sensitiveness of photodiodes sensible in the ultraviolet region of spectrum on the basis of selenid zinc and phosphide of gallium to 0,12 A/W and 0,2 A/W accordingly in the maximum of spectral description of sensitiveness. All so it is shown, that tape of nitrid silicon - dioxide of silicon a bit better clarifies silicon photodiode, especially on a wave-length 700 nm. Gluing composition, in general, worsens admission of tapes, and in a greater degree the admission of tape of nitrid silicon - dioxide of silicon.

Metal phosphonate coordination networks and frameworks as precursors of electrocatalysts for the hydrogen and oxygen evolution reactions

NASA Astrophysics Data System (ADS)

Zhang, Rui; El-Refaei, Sayed M.; Russo, Patrícia A.; Pinna, Nicola

2018-05-01

The hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) play key roles in the conversion of energy derived from renewable energy sources into chemical energy. Efficient, robust, and inexpensive electrocatalysts are necessary for driving these reactions at high rates at low overpotentials and minimize energetic losses. Recently, electrocatalysts derived from hybrid metal phosphonate compounds have shown high activity for the HER or OER. We review here the utilization of metal phosphonate coordination networks and metal-organic frameworks as precursors/templates for transition-metal phosphides, phosphates, or oxyhydroxides generated in situ in alkaline solutions, and their electrocatalytic performance in HER or OER.

Nanowire-Based Electrode for Acute In Vivo Neural Recordings in the Brain

PubMed Central

Suyatin, Dmitry B.; Wallman, Lars; Thelin, Jonas; Prinz, Christelle N.; Jörntell, Henrik; Samuelson, Lars; Montelius, Lars; Schouenborg, Jens

2013-01-01

We present an electrode, based on structurally controlled nanowires, as a first step towards developing a useful nanostructured device for neurophysiological measurements in vivo. The sensing part of the electrode is made of a metal film deposited on top of an array of epitaxially grown gallium phosphide nanowires. We achieved the first functional testing of the nanowire-based electrode by performing acute in vivo recordings in the rat cerebral cortex and withstanding multiple brain implantations. Due to the controllable geometry of the nanowires, this type of electrode can be used as a model system for further analysis of the functional properties of nanostructured neuronal interfaces in vivo. PMID:23431387

An epidemiological study of poisoning in northern Islamic Republic of Iran.

PubMed

Moghadamnia, A A; Abdollahi, M

2002-01-01

We examined the causes and mortality of poisoning in the province of Mazandaran. In all, 1751 poisoning cases referred to four main hospitals over a three-year period (1997-2000) were included. More poisoning cases were females (55.5%) than males (45.5%) but the proportional mortality for males was greater than for females (65% versus 35%). The greatest proportion of poisonings occurred between the ages of 16 and 25 years. Most frequent was intentional poisoning, followed by accidental and occupational poisoning. Medicines were the most common cause, followed by chemicals such as pesticides. Poisoning by opiates, aluminium or zinc phosphide, rodenticides, petroleum and ethanol intoxication was also observed. Pesticide poisoning was most frequently fatal.

Optical and interfacial electronic properties of diamond-like carbon films

NASA Technical Reports Server (NTRS)

Woollam, J. A.; Natarajan, V.; Lamb, J.; Khan, A. A.; Bu-Abbud, G.; Banks, B.; Pouch, J.; Gulino, D. A.; Domitz, S.; Liu, D. C.

1984-01-01

Hard, semitransparent carbon films were prepared on oriented polished crystal wafers of silicon, indium phosphide and gallium arsenide, as well as on KBr and quartz. Properties of the films were determined using IR and visible absorption spectrocopy, ellipsometry, conductance-capacitance spectroscopy and alpha particle-proton recoil spectroscopy. Preparation techniques include RF plasma decomposition of methane (and other hydrocarbons), ion beam sputtering, and dual-ion-beam sputter deposition. Optical energy band gaps as large as 2.7 eV and extinction coefficients lower than 0.1 at long wavelengths are found. Electronic state densities at the interface with silicon as low as 10 to the 10th states/eV sq cm per were found.

Indium phosphide solar cell research in the US: Comparison with nonphotovoltaic sources

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1989-01-01

Highlights of the InP solar cell research program are presented. Homojunction cells with AMO efficiences approaching 19 percent were demonstrated while 17 percent was achieved for indium tin oxide (ITO)/InP cells. The superior radiation resistance of these latter two cell configurations over both Si and GaAs were demonstrated. InP cells on board the LIPS III satellite show no degradation after more than a year in orbit. Computer modeling calculations were directed toward radiation damage predictions and the specification of concentrator cell parameters. Computed array specific powers, for a specific orbit, are used to compare the performance of an InP solar cell array to solar dynamic and nuclear systems.

TiO2-Based Indium Phosphide Metal-Oxide-Semiconductor Capacitor with High Capacitance Density.

PubMed

Cheng, Chun-Hu; Hsu, Hsiao-Hsuan; Chou, Kun-i

2015-04-01

We report a low-temperature InP p-MOS with a high capacitance density of 2.7 µF/cm2, low leakage current of 0.77 A/cm2 at 1 V and tight current distribution. The high-density and low-leakage InP MOS was achieved by using high-κ TiLaO dielectric and ultra-thin SiO2 buffer layer with a thickness of less than 0.5 nm. The obtained EOT can be aggressively scaled down to < 1 nm through the use of stacked TiLaO/SiO2 dielectric, which has the potential for the future application of high mobility III-V CMOS devices.

Technology considerations in EHF Satcom systems

NASA Astrophysics Data System (ADS)

Cuccia, C. L.

The history of mm-wave communications is reviewed briefly and technological requirements for future implementation of mm-wave communications satellites for military and commercial applications are surveyed. The driving force for expanding mm-wave usage is an impending saturation of the GEO arc over North America with C- and Ku-band Satcoms. For military purposes, 44 GHz operations would provide antijamming capabilities and on-board processing. Necessary developments for the mm-wave Satcoms include scanning and multiple beam antennas, low-noise amplifiers, filters which channelize the frequency band, frequency hopping synthesizers, QPSK and MSK modulation systems and improvements in GaAs and indium phosphide ICs. Finally, digital systems are being explored for commercial integrated global data, voice and video systems.

Theoretical and experimental research in space photovoltaics

NASA Technical Reports Server (NTRS)

Faur, Mircea; Faur, Maria

1995-01-01

Theoretical and experimental research is outlined for indium phosphide solar cells, other solar cells for space applications, fabrication and performance measurements of shallow homojunction InP solar cells for space applications, improved processing steps and InP material characterization with applications to fabrication of high efficiency radiation resistant InP solar cells and other opto-electronic InP devices, InP solar cells fabricated by thermal diffusion, experiment-based predicted high efficiency solar cells fabricated by closed-ampoule thermal diffusion, radiation resistance of diffused junction InP solar cells, chemical and electrochemical characterization and processing of InP diffused structures and solar cells, and progress in p(+)n InP diffused solar cells.

Enhanced monolayer MoS2/InP heterostructure solar cells by graphene quantum dots

NASA Astrophysics Data System (ADS)

Wang, Peng; Lin, Shisheng; Ding, Guqiao; Li, Xiaoqiang; Wu, Zhiqian; Zhang, Shengjiao; Xu, Zhijuan; Xu, Sen; Lu, Yanghua; Xu, Wenli; Zheng, Zheyang

2016-04-01

We demonstrate significantly improved photovoltaic response of monolayer molybdenum disulfide (MoS2)/indium phosphide (InP) van der Waals heterostructure induced by graphene quantum dots (GQDs). Raman and photoluminescence measurements indicate that effective charge transfer takes place between GQDs and MoS2, which results in n-type doping of MoS2. The doping effect increases the barrier height at the MoS2/InP heterojunction, thus the averaged power conversion efficiency of MoS2/InP solar cells is improved from 2.1% to 4.1%. The light induced doping by GQD provides a feasible way for developing more efficient MoS2 based heterostructure solar cells.

High-pressure behavior of iron-nickel-cobalt phosphides and its implications for meteorites and planetary cores

NASA Astrophysics Data System (ADS)

Dera, P.; Lavina, B.; Borkowski, L. A.; Downs, R. T.; Prewitt, C. T.; Prakapenka, V.; Rivers, M. L.; Sutton, S.; Boctor, N.

2008-12-01

Minerals with composition (Fe,Ni)xP, are rare, but important accessory phases present in iron and chondrite meteorites. The occurrence of these minerals in meteoritic samples is believed to originate either from the equilibrium condensation of protoplanetary materials taking place in solar nebulae or from crystallization processes in the cores of parent bodies. Fe-Ni phosphides are considered an important candidate for a minor phase present in Earth's core, and at least partially responsible for the observed core density deficit with respect to pure Fe. We report results of high-pressure high-temperature single-crystal X- ray diffraction experiments with end-members belonging to the (Fe,Ni,Co)2P family, including Fe2P, Ni2P and Co2P. A new phase transition to the Co2Si-type structure (allabogdanite) has been found in Fe2P barringerite at 8.0 GPa, upon heating. The high-pressure phase can be quenched metastably to ambient conditions and then, if heated again, it transforms back to barringerite. Ni2P barringerite does not undergo transformation to allabogdanite structure up to 50 GPa, but instead exhibits incongruent melting with formation of pyrite-type NiP2 and Ni-P glass. Our results indicate that the presence of allabogdanite in meteoritic samples places two important constraints on the thermodynamic history of the meteorite. First, it imposes a minimum pressure and temperature for the formation of the Fe2P, and additionally rules out any higher temperature low pressure alterations. If present in the Earth's core, Fe2P will have the allabogdanite rather than the barringerite structure. Crystal chemical trends in the compressibility of (Fe,Ni,Co)2P minerals, as well as polymorphic transition paths are analyzed in the context of Earth and planetary core composition and properties.

Strongly-guided indium phosphide/indium gallium arsenic phosphide Mach-Zehnder modulator for optical communications

NASA Astrophysics Data System (ADS)

Betty, Ian Brian

2006-12-01

The development of strongly-guided InP/In1-x GaxAsyP 1-y based Mach-Zehnder optical modulators for 10Gb/s telecommunications is detailed. The modulators have insertion losses including coupling as low as 4.5dB, due to the incorporation of monolithically integrated optical mode spot-size converters (SSC's). The modulators are optimized to produce system performance that is independent of optical coupling alignment and for wavelength operation between 1525nm and 1565nm. A negatively chirped Mach-Zehnder modulator design is demonstrated, giving optimal dispersion-limited reach for 10Gb/s ON/OFF-keying modulation. It is shown that the optical system performance for this design can be determined from purely DC based optical measurements. A Mach-Zehnder modulator design invoking nearly no transient frequency shifts under intensity modulation is also presented, for the first time, using phase-shifter implementations based on the Quantum-Confined-Stark-Effect (QCSE). The performance impact on the modulator from the higher-order vertical and lateral waveguide modes found in strongly-guided waveguides has been determined. The impact of these higher-order modes has been minimized using the design of the waveguide bends, MMI structures, and doping profiles. The fabrication process and optical design for the spot-size mode converters are also thoroughly explored. The SSC structures are based on butt-joined vertically tapered passive waveguide cores within laterally flared strongly-guided ridges, making them compatible with any strong-guiding waveguide structure. The flexibility of the SSC process is demonstrated by the superior performance it has also enabled in a 40Gb/s electro-absorption modulator. The presented electro-absorption modulator has 3.6dB fiber-to-fiber insertion loss, polarization dependent loss (PDL) of only 0.3dB over 15dB extinction, and low absolute chirp (|alpha H| < 0.6) over the full dynamic range.

Photonic crystal Fano resonances for realizing optical switches, lasers, and non-reciprocal elements

NASA Astrophysics Data System (ADS)

Bekele, Dagmawi A.; Yu, Yi; Hu, Hao; Ding, Yunhong; Sakanas, Aurimas; Ottaviano, Luisa; Semenova, Elizaveta; Oxenløwe, Leif K.; Yvind, Kresten; Mork, Jesper

2017-08-01

We present our work on photonic crystal membrane devices exploiting Fano resonance between a line-defect waveguide and a side coupled nanocavity. Experimental demonstration of fast and compact all-optical switches for wavelength-conversion is reported. It is shown how the use of an asymmetric structure in combination with cavity-enhanced nonlinearity can be used to realize non-reciprocal transmission at ultra-low power and with large bandwidth. A novel type of laser structure, denoted a Fano laser, is discussed in which one of the mirrors is based on a Fano resonance. Finally, the design, fabrication and characterization of grating couplers for efficient light coupling in and out of the indium phosphide photonic crystal platform is discussed.

Gallium phosphide high temperature diodes

NASA Technical Reports Server (NTRS)

Chaffin, R. J.; Dawson, L. R.

1981-01-01

High temperature (300 C) diodes for geothermal and other energy applications were developed. A comparison of reverse leakage currents of Si, GaAs, and GaP was made. Diodes made from GaP should be usable to 500 C. A Liquid Phase Epitaxy (LPE) process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers were cut into die and metallized to make the diodes. These diodes produce leakage currents below ten to the -9th power A/sq cm at 400 C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.

Room-temperature Coulomb staircase in semiconducting InP nanowires modulated with light illumination.

PubMed

Yamada, Toshishige; Yamada, Hidenori; Lohn, Andrew J; Kobayashi, Nobuhiko P

2011-02-04

Detailed electron transport analysis is performed for an ensemble of conical indium phosphide nanowires bridging two hydrogenated n(+)-silicon electrodes. The current-voltage (I-V) characteristics exhibit a Coulomb staircase in the dark with a period of ∼ 1 V at room temperature. The staircase is found to disappear under light illumination. This observation can be explained by assuming the presence of a tiny Coulomb island, and its existence is possible due to the large surface depletion region created within contributing nanowires. Electrons tunnel in and out of the Coulomb island, resulting in the Coulomb staircase I-V. Applying light illumination raises the electron quasi-Fermi level and the tunneling barriers are buried, causing the Coulomb staircase to disappear.

Heterodoped nanotubes: theory, synthesis, and characterization of phosphorus-nitrogen doped multiwalled carbon nanotubes.

PubMed

Cruz-Silva, Eduardo; Cullen, David A; Gu, Lin; Romo-Herrera, Jose Manuel; Muñoz-Sandoval, Emilio; López-Urías, Florentino; Sumpter, Bobby G; Meunier, Vincent; Charlier, Jean-Christophe; Smith, David J; Terrones, Humberto; Terrones, Mauricio

2008-03-01

Arrays of multiwalled carbon nanotubes doped with phosphorus (P) and nitrogen (N) are synthesized using a solution of ferrocene, triphenyl-phosphine, and benzylamine in conjunction with spray pyrolysis. We demonstrate that iron phosphide (Fe(3)P) nanoparticles act as catalysts during nanotube growth, leading to the formation of novel PN-doped multiwalled carbon nanotubes. The samples were examined by high resolution electron microscopy and microanalysis techniques, and their chemical stability was explored by means of thermogravimetric analysis in the presence of oxygen. The PN-doped structures reveal important morphology and chemical changes when compared to N-doped nanotubes. These types of heterodoped nanotubes are predicted to offer many new opportunities in the fabrication of fast-response chemical sensors.

High Efficiency InP Solar Cells from Low Toxicity Tertiarybutylphosphine

NASA Technical Reports Server (NTRS)

Hoffman, Richard W., Jr.; Fatemi, Navid S.; Wilt, David M.; Jenkins, Phillip P.; Brinker, David J.; Scheiman, David A.

1994-01-01

Large scale manufacture of phosphide based semiconductor devices by organo-metallic vapor phase epitaxy (OMVPE) typically requires the use of highly toxic phosphine. Advancements in phosphine substitutes have identified tertiarybutylphosphine (TBP) as an excellent precursor for OMVPE of InP. High quality undoped and doped InP films were grown using TBP and trimethylindium. Impurity doped InP films were achieved utilizing diethylzinc and silane for p and n type respectively. 16 percent efficient solar cells under air mass zero, one sun intensity were demonstrated with Voc of 871 mV and fill factor of 82.6 percent. It was shown that TBP could replace phosphine, without adversely affecting device quality, in OMVPE deposition of InP thus significantly reducing toxic gas exposure risk.

Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals.

PubMed

Gresback, Ryan; Hue, Ryan; Gladfelter, Wayne L; Kortshagen, Uwe R

2011-01-12

Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown around the plasma-synthesized InP NCs in a liquid phase reaction. Photoluminescence with quantum yields as high as 15% were observed for the InP/ZnS core-shell NCs.

Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals

PubMed Central

2011-01-01

Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown around the plasma-synthesized InP NCs in a liquid phase reaction. Photoluminescence with quantum yields as high as 15% were observed for the InP/ZnS core-shell NCs. PMID:21711589

Combined plasma gas-phase synthesis and colloidal processing of InP/ZnS core/shell nanocrystals

NASA Astrophysics Data System (ADS)

Gresback, Ryan; Hue, Ryan; Gladfelter, Wayne L.; Kortshagen, Uwe R.

2011-12-01

Indium phosphide nanocrystals (InP NCs) with diameters ranging from 2 to 5 nm were synthesized with a scalable, flow-through, nonthermal plasma process at a rate ranging from 10 to 40 mg/h. The NC size is controlled through the plasma operating parameters, with the residence time of the gas in the plasma region strongly influencing the NC size. The NC size distribution is narrow with the standard deviation being less than 20% of the mean NC size. Zinc sulfide (ZnS) shells were grown around the plasma-synthesized InP NCs in a liquid phase reaction. Photoluminescence with quantum yields as high as 15% were observed for the InP/ZnS core-shell NCs.

Optical properties of nanowire metamaterials with gain

NASA Astrophysics Data System (ADS)

Lima, Joaquim; Adam, Jost; Rego, Davi; Esquerre, Vitaly; Bordo, Vladimir

2016-11-01

The transmittance, reflectance and absorption of a nanowire metamaterial with optical gain are numerically simulated and investigated. It is assumed that the metamaterial is represented by aligned silver nanowires embedded into a semiconductor matrix, made of either silicon or gallium phosphide. The gain in the matrix is modeled by adding a negative imaginary part to the dielectric function of the semiconductor. It is found that the optical coefficients of the metamaterial depend on the gain magnitude in a non-trivial way: they can both increase and decrease with gain depending on the lattice constant of the metamaterial. This peculiar behavior is explained by the field redistribution between the lossy metal nanowires and the amplifying matrix material. These findings are significant for a proper design of nanowire metamaterials with low optical losses for diverse applications.

Indium phosphide-based monolithically integrated PIN waveguide photodiode readout for resonant cantilever sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siwak, N. P.; Laboratory for the Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740; Fan, X. Z.

2014-10-06

An integrated photodiode displacement readout scheme for a microelectromechanical cantilever waveguide resonator sensing platform is presented. III-V semiconductors are used to enable the monolithic integration of passive waveguides with active optical components. This work builds upon previously demonstrated results by measuring the displacement of cantilever waveguide resonators with on-chip waveguide PIN photodiodes. The on-chip integration of the readout provides an additional 70% improvement in mass sensitivity compared to off-chip photodetector designs due to measurement stability and minimized coupling loss. In addition to increased measurement stability, reduced packaging complexity is achieved due to the simplicity of the readout design. We havemore » fabricated cantilever waveguides with integrated photodetectors and experimentally characterized these cantilever sensors with monolithically integrated PIN photodiodes.« less

Potential for use of InP solar cells in the space radiation environment

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

1985-01-01

Indium phosphide solar cells were observed to have significantly higher radiation resistance than either GaAs or Si after exposure to 10 MeV proton irradiation data and previous 1 MeV electron data together with projected efficiencies for InP, it was found that these latter cells produced more output power than either GaAs or Si after specified fluences of 10 MeV protons and 1 MeV electrons. Estimates of expected performance in a proton dominated space orbit yielded much less degradation for InP when compared to the remaining two cell types. It was concluded that, with additional development to increase efficiency, InP solar cells would perform significantly better than either GaAs or Si in the space radiation environment.

Low Noise Amplifiers for 140 Ghz Wide-Band Cryogenic Receivers

NASA Technical Reports Server (NTRS)

Larkoski, Patricia V.; Kangaslahti, Pekka; Samoska, Lorene; Lai, Richard; Sarkozy, Stephen

2013-01-01

We report S-parameter and noise measurements for three different Indium Phosphide 35-nanometer-gate-length High Electron Mobility Transistor (HEMT) Low Noise Amplifier (LNA) designs operating in the frequency range centered on 140 gigahertz. When packaged in a Waveguide Rectangular-6.1 waveguide housing, the LNAs have an average measured noise figure of 3.0 decibels - 3.6 decibels over the 122-170 gigahertz band. One LNA was cooled to 20 degrees Kelvin and a record low noise temperature of 46 Kelvin, or 0.64 decibels noise figure, was measured at 152 gigahertz. These amplifiers can be used to develop receivers for instruments that operate in the 130-170 gigahertz atmospheric window, which is an important frequency band for ground-based astronomy and millimeter-wave imaging applications.

Optimization Of Shear Modes To Produce Enhanced Bandwidth In Ghz GaP Bragg Cells

NASA Astrophysics Data System (ADS)

Soos, J., I.; Rosemeier, R. G.; Rosenbaum, J.

1988-02-01

Applications of Gallium Phosphide (GaP) acousto-optic devices, at wavelengths from 570nm - 1.06um seem to be ideal for fiber optic modulators, scanners, deflectors, frequency shifters, Q-switches and mode lockers. One of the major applications are for RF spectrometers in early warning radar receivers and auto-correlators. Longitudinal GaP acousto-optic Bragg cells which have respectively operational frequencies in the range of 200 MHz - 3 GHz and diffraction efficiencies in the range of 120%/RF watt to 1%/RF watt have recently been fabricated. Comparatively, shear GaP devices which have operational frequencies in the range of 200 MHz to 2 GHz and diffraction efficiencies from 80%/RF watt to 7%/RF watt have also been constructed.

Single-Pole Double-Throw MMIC Switches for a Microwave Radiometer

NASA Technical Reports Server (NTRS)

Montes, Oliver; Dawson, Douglas E.; Kangaslahti, Pekka P.

2012-01-01

In order to reduce the effect of gain and noise instabilities in the RF chain of a microwave radiometer, a Dicke radiometer topology is often used, as in the case of the proposed surface water and ocean topography (SWOT) radiometer instrument. For this topology, a single-pole double-throw (SPDT) microwave switch is needed, which must have low insertion loss at the radiometer channel frequencies to minimize the overall receiver noise figure. Total power radiometers are limited in accuracy due to the continuous variation in gain of the receiver. High-frequency SPDT switches were developed in the form of monolithic microwave integrated circuits (MMICs) using 75 micron indium phosphide (InP) PIN-diode technology. These switches can be easily integrated into Dicke switched radiometers that utilize microstrip technology.

ITO/InP solar cells: A comparison of devices fabricated by ion beam and RF sputtering of the ITO

NASA Technical Reports Server (NTRS)

Coutts, T. J.

1987-01-01

This work was performed with the view of elucidating the behavior of indium tin oxide/indium phosphide (ITO/InP) solar cells prepared by RF and ion beam sputtering. It was found that using RF sputter deposition of the ITO always leads to more efficient devices than ion beam sputter deposition. An important aspect of the former technique is the exposure of the single crystal p-InP substrates to a very low plasma power prior to deposition. Substrates treated in this manner have also been used for ion beam deposition of ITO. In this case the cells behave very similarly to the RF deposited cells, thus suggesting that the lower power plasma exposure (LPPE) is the crucial process step.

Photovoltaic options for solar electric propulsion

NASA Technical Reports Server (NTRS)

Stella, Paul M.; Flood, Dennis J.

1990-01-01

During the past decade, a number of advances have occurred in solar cell and array technology. These advances have lead to performance improvement for both conventional space arrays and for advanced technology arrays. Performance enhancements have occurred in power density, specific power, and environmental capability. Both state-of-the-art and advanced development cells and array technology are discussed. Present technology will include rigid, rollout, and foldout flexible substrate designs, with silicon and GaAs solar cells. The use of concentrator array systems is also discussed based on both DOD and NASA efforts. The benefits of advanced lightweight array technology, for both near term and far term utilization, and of advanced high efficiency, thin, radiation resistant cells is examined. This includes gallium arsenide on germaniun substrates, indium phosphide, and thin film devices such as copper indium diselenide.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavina, Barbara; Kim, Eunja; Cynn, Hyunchae

Using combined experimental and computational approaches, we show that at 43 GPa and 1300 K gallium phosphide adopts the super-Cmcm structure, here indicated with its Pearson notation oS24. First-principles enthalpy calculations demonstrate that this structure is more thermodynamically stable above ~20 GPa than previously proposed polymorphs. Here, in contrast to other polymorphs, the oS24 phase shows a strong bonding differentiation and distorted fivefold coordination geometries of both P atoms. The shortest bond of the phase is a single covalent P–P bond measuring 2.171(11) Å at synthesis pressure. Phosphorus dimerization in GaP sheds light on the nature of the super-Cmcm phasemore » and provides critical new insights into the high-pressure polymorphism of octet semiconductors. Bond directionality and anisotropy explain the relatively low symmetry of this high-pressure phase.« less

High-efficiency GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy

PubMed Central

2011-01-01

We report the initial results of GaAs and GaInP solar cells grown by all solid-state molecular-beam-epitaxy (MBE) technique. For GaAs single-junction solar cell, with the application of AlInP as the window layer and GaInP as the back surface field layer, the photovoltaic conversion efficiency of 26% at one sun concentration and air mass 1.5 global (AM1.5G) is realized. The efficiency of 16.4% is also reached for GaInP solar cell. Our results demonstrate that the MBE-grown phosphide-contained III-V compound semiconductor solar cell can be quite comparable to the metal-organic-chemical-vapor-deposition-grown high-efficiency solar cell. PMID:22040124

Synthetic Development of Low Dimensional Materials

DOE PAGES

Men, Long; White, Miles A.; Andaraarachchi, Himashi; ...

2016-11-02

Here, in this invited paper, we highlight some of our most recent work on the synthesis of low dimensional nanomaterials. Current graduate students and members of our group present four specific case systems: Nowotny-Juza phases, nickel phosphides, germanium-based core/shells, and organolead mixed-halide perovskites. Each system is accompanied by commentary from the student involved, which explains our motivation behind our work, as well as by a protocol detailing the key experimental considerations involved in their synthesis. We trust these and similar efforts by others and us will help further advance our understanding of the broader field of synthetic nanomaterials chemistry, while,more » at the same time, highlighting how important this area is to the development of new materials for technologically relevant applications.« less

InP nanopore arrays for photoelectrochemical hydrogen generation.

PubMed

Li, Qiang; Zheng, Maojun; Zhang, Bin; Zhu, Changqing; Wang, Faze; Song, Jingnan; Zhong, Miao; Ma, Li; Shen, Wenzhong

2016-02-19

We report a facile and large-scale fabrication of highly ordered one-dimensional (1D) indium phosphide (InP) nanopore arrays (NPs) and their application as photoelectrodes for photoelectrochemical (PEC) hydrogen production. These InP NPs exhibit superior PEC performance due to their excellent light-trapping characteristics, high-quality 1D conducting channels and large surface areas. The photocurrent density of optimized InP NPs is 8.9 times higher than that of planar counterpart at an applied potential of +0.3 V versus RHE under AM 1.5G illumination (100 mW cm(-2)). In addition, the onset potential of InP NPs exhibits 105 mV of cathodic shift relative to planar control. The superior performance of the nanoporous samples is further explained by Mott-Schottky and electrochemical impedance spectroscopy ananlysis.

The effect of N-acetyl cysteine (NAC) on aluminum phosphide poisoning inducing cardiovascular toxicity: a case-control study.

PubMed

Taghaddosinejad, Fakhreddin; Farzaneh, Esmaeil; Ghazanfari-Nasrabad, Mahdi; Eizadi-Mood, Nastaran; Hajihosseini, Morteza; Mehrpour, Omid

2016-01-01

Aluminum phosphide (AlP) is a very effective indoor and outdoor pesticide. We investigated the effects of N-acetyl cysteine (NAC) on the survival time, hemodynamics, and cardiac biochemical parameters at various time intervals in some cases of AlP poisoning. This research was a case-control study to evaluate 63 AlP poisoned patients during 2010-2012. Patients with cardiovascular complications of AlP to be treated with intravenous NAC plus conventional treatment were considered as the case group and compared with patients who did not receive NAC. NAC infusion was administered to the case group at 300 mg/kg for 20 h. The data gathered included age, sex, heart rate, Systolic blood pressure (SBP), creatine phosphokinase (CPK), creatine kinase MB (CK-MB), and ECG at the admission time and 12, 18, and 24 h after admission. Analysis of repeated measures was performed to check the variability of parameters over time. The mean ages in the case and control groups were 26.65 ± 1.06 (19-37 years) and 28.39 ± 1.11 (18-37 years), respectively (P = 0.266). Most of the patients were female (56.5%). CK-MB means were significantly different between the two groups, but no differences between the other variables were observed. Also, CK-MB, CPK, heart rate, and systolic blood pressure means became significantly different over time (0, 12, 18, and 24 h) in both groups (P < 0.001). NAC prevented sharp heart rate fluctuations in AlP patients in the case group. Regarding the outcomes, 17 patients died (10 patients in the control and 7 patients in the case groups). No side-effects of NAC were observed. Our patients could be managed by the positive role of NAC as the biochemical index of cardiotoxicity was found to elevate in both the case and control groups. Therefore, for the management protocol optimization, NAC evaluation should be done in further cases.

Doping of epitaxial III-V semiconductors for optoelectronic and magnetoelectronic applications

NASA Astrophysics Data System (ADS)

Overberg, Mark Eddy

Doped III-V semiconducting materials were studied in this dissertation for use in optoelectronic and magnetoelectronic applications. The specific areas of use are emitters for fiber optic communication and room temperature ferromagnetic layers for spintronic devices. The general requirement for both application areas is the ability to heavily dope (or alloy) the III-Vs with the intended active element, while still maintaining good crystallinity and semiconducting properties. Four dopant/semiconductor systems were investigated: erbium in gallium nitride (GaN:Er), europium in gallium nitride (GaN:Eu), manganese in gallium nitride (GaMnN), and manganese in gallium phosphide (GaMnP). These materials were fabricated using variants of the molecular beam epitaxy (MBE) technique, where beams of the constituent elements are produced in a high vacuum environment. The technique allows for a wide variety of parameters to be adjusted during the material preparation. The materials were deposited on sapphire, gallium nitride, and gallium phosphide surfaces; with particular emphasis on the correlation between growth conditions and the final chemical, structural, morphological, electronic, optical, and magnetic properties. The materials were characterized using a variety of techniques. Results with the GaN:Er material indicated that several percent of Er could be successfully incorporated into the material, and that the optical emission could be increased by incorporating C impurities into the film. These impurities were found to increase the overall emission and decrease the quenching of the emission with temperature. Optical emission results for GaN:Eu indicated that this material produced a visible red emission that was brighter under optical excitation than the AlGaAs used in commercial red emitting devices. The dilute magnetic semiconductors n-GaMnN and p-GaMnP were produced for the first time by the MBE technique. The SQUID magnetometry and magnetotransport results for n-GaMnN indicated the presence of ferromagnetic ordering with a Curie temperature between 20 K and 25 K. Magnetic measurements of the p-GaMnP indicated the presence of ferromagnetic ordering to 250 K, far above the theoretically predicted value of 100 K. Similar results were also produced by the direct implantation of Mn into GaP.

Rational Design of Zinc Phosphide Heterojunction Photovoltaics

NASA Astrophysics Data System (ADS)

Bosco, Jeffrey Paul

The prospect of terawatt-scale electricity generation using a photovoltaic (PV) device places strict requirements on the active semiconductor optoelectronic properties and elemental abundance. After reviewing the constraints placed on an ``earth-abundant'' solar absorber, we find zinc phosphide (α-Zn 3P2) to be an ideal candidate. In addition to its near-optimal direct band gap of 1.5 eV, high visible-light absorption coefficient (>10. 4cm-1), and long minority-carrier diffusion length (>5 μm), Zn3P 2 is composed of abundant Zn and P elements and has excellent physical properties for scalable thin-film deposition. However, to date, a Zn 3P2 device of sufficient efficiency for commercial applications has not been demonstrated. Record efficiencies of 6.0% for multicrystalline and 4.3% for thin-film cells have been reported, respectively. Performance has been limited by the intrinsic p-type conductivity of Zn3P 2 which restricts us to Schottky and heterojunction device designs. Due to our poor understanding of Zn3P2 interfaces, an ideal heterojunction partner has not yet been found. The goal of this thesis is to explore the upper limit of solar conversion efficiency achievable with a Zn3P2 absorber through the design of an optimal heterojunction PV device. To do so, we investigate three key aspects of material growth, interface energetics, and device design. First, the growth of Zn3P2 on GaAs(001) is studied using compound-source molecular-beam epitaxy (MBE). We successfully demonstrate the pseudomorphic growth of Zn3P2 epilayers of controlled orientation and optoelectronic properties. Next, the energy-band alignments of epitaxial Zn3P2 and II-VI and III-V semiconductor interfaces are measured via high-resolution x-ray photoelectron spectroscopy in order to determine the most appropriate heterojunction partner. From this work, we identify ZnSe as a nearly ideal n-type emitter for a Zn3P 2 PV device. Finally, various II-VI/Zn3P2 heterojunction solar cells designs are fabricated, including substrate and superstrate architectures, and evaluated based on their solar conversion efficiency.

Brazing method

DOEpatents

McCormick, James T.; Ferry, Paul B.; Hall, John C.

1981-10-06

There is disclosed a positive cathode electrode structure formed by brazing a thin porous membrane to a backing material by preselecting a predetermined area of the thin porous membrane and thereafter providing a braze flow barrier throughout the remainder of the membrane and electrolessly plating a nickel-phosphide alloy on the backing material, or in this case the honeycomb structure. The preselected area of the thin porous membrane is placed in intimate contact with the electrolessly plated portion of the backing material and heated to elevated temperatures in the absence of oxygen to form a brazed joint limited to a preselected area. If the braze flow barrier is provided by application of a liquid organic solvent, then the organic solvent is driven off by maintaining the thin porous membrane at elevated temperatures for an extended period of time prior to the brazing operation.

Femtosecond buildup of phonon-plasmon coupling in photoexcited InP observed by ultrabroadband THz probing

NASA Astrophysics Data System (ADS)

Huber, Rupert; Kübler, Carl; Tübel, Stefan; Leitenstorfer, Alfred

2006-02-01

We study the ultrafast transition of a pure longitudinal optical phonon resonance to a coupled phonon-plasmon system. Following 10-fs photoexcitation of intrinsic indium phosphide, ultrabroadband THz opto-electronics monitors the buildup of coherent beats of the emerging hybrid modes directly in the time domain with sub-cycle resolution. Mutual repulsion and redistribution of the oscillator strength of the interacting phonons and plasmons are seen to emerge on a delayed femtosecond time scale. Both branches of the mixed modes are monitored for various excitation densities N. We observe a pronounced anticrossing of the coupled resonances as a function of N. The characteristic formation time for phonon-plasmon coupling exhibits density dependence. The time is approximately set by one oscillation cycle of the upper branch of the mixed modes.

Induced changes in refractive index, optical band gap, and absorption edge of polycarbonate-SiO2 thin films by Vis-IR lasers

NASA Astrophysics Data System (ADS)

Ehsani, Hassan; Akhoondi, Somaieh

2016-09-01

In this experimental work, we have studied induced changes in refractive index, extinction coefficient, and optical band-gap of Bisphenol-A-polycarbonate (BPA-PC) coated with a uniform and thin, anti-scratch SiO2 film irradiated by visible to near-infrared lasers at 532 nm (green),650 nm(red), and 980 nm (IR)wavelength lasers with different energy densities. Our lasers sources are indium-gallium-aluminum-phosphide, second harmonic of neodymium-YAG-solid state lasers and gallium-aluminum-arsenide-semiconductor laser. The energy densities of our sources have been changed by changing the spot size of incident laser. samples transmission spectra were monitored by carry500 spectrophotometer and induced changes in optical properties are evaluated by using, extrapolation of the transmission spectrum through Swanepoel method and computer application

The need for translational research on antidotes for pesticide poisoning

PubMed Central

Buckley, Nick A; Eddleston, Michael; Dawson, Andrew H

2006-01-01

Summary Pesticide poisoning kills hundreds of thousands of people in the Asia Pacific region each year. The majority are from deliberate self-poisoning with organophosphorus pesticides (OP), aluminium phosphide and paraquat. The current response from a public health, medical and research perspective is inadequate. There are few proven or effective treatments; in addition, very little clinical research has been done to transfer antidotes shown to work in animal studies into clinical practice. The human toxicity of pesticides is poorly studied and better information might inform a more sustained and appropriate regulatory response. Further understanding may also lead to improvement in diagnosis and treatment. The few effective treatments are not being recommended or delivered in an optimal and timely fashion to poisoned patients. A regional approach to facilitate appropriate pricing, packaging and delivery of antidotes is required. PMID:16405459

LETTER TO THE EDITOR: Surface passivation of (100) InP by organic thiols and polyimide as characterized by steady-state photoluminescence

NASA Astrophysics Data System (ADS)

Schvartzman, M.; Sidorov, V.; Ritter, D.; Paz, Y.

2001-10-01

A method for the passivation of indium phosphide, based on thiolated organic self-assembled monolayers (SAMs) that form highly ordered, close-packed structures on the semiconductor surface, is presented. It is shown that the intensity of steady-state photoluminescence (PL) of n-type InP wafers covered with the thiolated SAMs increases significantly (as much as 14-fold) upon their covering with the monolayers. The ease with which one can tailor the outer functional groups of the SAMs provides a way to connect this new class of passivators with standard encapsulators, such as polyimide. Indeed, the PL intensity of SAM-coated InP wafers was not altered upon their overcoating with polyimide, despite the high curing temperature of the polymer (200 °C).

Remote plasma enhanced chemical vapor deposition of GaP with in situ generation of phosphine precursors

NASA Technical Reports Server (NTRS)

Choi, S. W.; Lucovsky, G.; Bachmann, Klaus J.

1993-01-01

Thin homoepitaxial films of gallium phosphide (GaP) were grown by remote plasma enhanced chemical vapor deposition utilizing in situ generated phosphine precursors. The GaP forming reaction is kinetically controlled with an activation energy of 0.65 eV. The increase of the growth rate with increasing radio frequency (rf) power between 20 and 100 W is due to the combined effects of increasingly complete excitation and the spatial extension of the glow discharge toward the substrate, however, the saturation of the growth rate at even higher rf power indicates the saturation of the generation rate of phosphine precursors at this condition. Slight interdiffusion of P into Si and Si into GaP is indicated from GaP/Si heterostructures grown under similar conditions as the GaP homojunctions.

Remote plasma enhanced chemical vapor deposition of GaP with in situ generation of phosphine precursors

NASA Technical Reports Server (NTRS)

Choi, S. W.; Lucovsky, G.; Bachmann, K. J.

1992-01-01

Thin homoepitaxial films of gallium phosphide (GaP) have been grown by remote plasma enhanced chemical vapor deposition utilizing in situ-generated phosphine precursors. The GaP forming reaction is kinetically controlled with an activation energy of 0.65 eV. The increase of the growth rate with increasing radio frequency (RF) power between 20 and 100 W is due to the combined effects of increasingly complete excitation and the spatial extension of the glow discharge toward the substrate; however, the saturation of the growth rate at even higher RF power indicates the saturation of the generation rate of phosphine precursors at this condition. Slight interdiffusion of P into Si and Si into GaP is indicated from GaP/Si heterostructures grown under similar conditions as the GaP homojunctions.

The Adjunctive Soft-Tissue Diode Laser in Orthodontics.

PubMed

Borzabadi-Farahani, Ali

2017-04-01

Lasers are a relatively new addition to the orthodontist's armamentarium. This article reviews the fundamental basic science of available soft-tissue lasers, with an emphasis on diode lasers, and discusses various adjunct applications of the diode laser for soft-tissue orthodontic procedures. Diode lasers function by cutting with an initiated hot tip and produce minimal to no interaction with healthy dental hard tissue, making them suitable for soft-tissue procedures. The contact cutting mode provides enhanced bloodless site visibility and facility to perform delicate soft tissue procedures, which is important in areas with difficult access. Such adjunctive uses include laser gingivectomy to improve oral hygiene or bracket positioning, esthetic laser gingival recontouring, and laser exposure of superficially impacted teeth. Selected cases treated with a 940-nm indium-gallium-arsenide-phosphide (InGaAsP) diode laser will be presented.

Fiber Bragg grating sensor interrogators on chip: challenges and opportunities

NASA Astrophysics Data System (ADS)

Marin, Yisbel; Nannipieri, Tiziano; Oton, Claudio J.; Di Pasquale, Fabrizio

2017-04-01

In this paper we present an overview of the current efforts towards integration of Fiber Bragg Grating (FBG) sensor interrogators. Different photonic integration platforms will be discussed, including monolithic planar lightwave circuit technology, silicon on insulator (SOI), indium phosphide (InP) and gallium arsenide (GaAs) material platforms. Also various possible techniques for wavelength metering and methods for FBG multiplexing will be discussed and compared in terms of resolution, dynamic performance, multiplexing capabilities and reliability. The use of linear filters, array waveguide gratings (AWG) as multiple linear filters and AWG based centroid signal processing techniques will be addressed as well as interrogation techniques based on tunable micro-ring resonators and Mach-Zehnder interferometers (MZI) for phase sensitive detection. The paper will also discuss the challenges and perspectives of photonic integration to address the increasing requirements of several industrial applications.

Design optimization and tolerance analysis of a spot-size converter for the taper-assisted vertical integration platform in InP.

PubMed

Tolstikhin, Valery; Saeidi, Shayan; Dolgaleva, Ksenia

2018-05-01

We report on the design optimization and tolerance analysis of a multistep lateral-taper spot-size converter based on indium phosphide (InP), performed using the Monte Carlo method. Being a natural fit to (and a key building block of) the regrowth-free taper-assisted vertical integration platform, such a spot-size converter enables efficient and displacement-tolerant fiber coupling to InP-based photonic integrated circuits at a wavelength of 1.31 μm. An exemplary four-step lateral-taper design featuring 0.35 dB coupling loss at optimal alignment of a standard single-mode fiber; ≥7  μm 1 dB displacement tolerance in any direction in a facet plane; and great stability against manufacturing variances is demonstrated.

Synthesis and characterization of hollow spherical copper phosphide (Cu 3P) nanopowders

NASA Astrophysics Data System (ADS)

Liu, Shuling; Qian, Yitai; Xu, Liqiang

2009-03-01

In this paper, hollow spherical Cu 3P nanopowders were synthesized by using copper sulfate pentahydrate (CuSO 4ṡ5H 2O) and yellow phosphorus in a mixed solvent of glycol, ethanol and water at 140-180 ∘C for 12 h. X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), electron diffraction pattern (ED) and transmission electronic microscopy (TEM) studies show that the as-synthesized nanocrystal is pure hexagonal phase Cu 3P with a hollow spherical morphology. Based on the TEM observations, a possible aggregation growth mechanism was proposed for the formation of Cu 3P hollow structures. Meanwhile, the effects of some key factors such as solvents, reaction temperature and reaction time on the final formation of the Cu 3P hollow structure were also discussed.

Influence of Ni-P Coated SiC and Laser Scan Speed on the Microstructure and Mechanical Properties of IN625 Metal Matrix Composites

NASA Astrophysics Data System (ADS)

Sateesh, N. H.; Kumar, G. C. Mohan; Krishna, Prasad

2015-12-01

Nickel based Inconel-625 (IN625) metal matrix composites (MMCs) were prepared using pre-heated nickel phosphide (Ni-P) coated silicon carbide (SiC) reinforcement particles by Direct Metal Laser Sintering (DMLS) additive manufacturing process under inert nitrogen atmosphere to obtain interface influences on MMCs. The distribution of SiC particles and microstructures were characterized using optical and scanning electron micrographs, and the mechanical behaviours were thoroughly examined. The results clearly reveal that the interface integrity between the SiC particles and the IN625 matrix, the mixed powders flowability, the SiC ceramic particles and laser beam interaction, and the hardness, and tensile characteristics of the DMLS processed MMCs were improved effectively by the use of Ni-P coated SiC particles.

Phase-controlled synthesis of polymorphic tungsten diphosphide with hybridization of monoclinic and orthorhombic phases as a novel electrocatalyst for efficient hydrogen evolution

NASA Astrophysics Data System (ADS)

Pi, Mingyu; Wu, Tianli; Guo, Weimeng; Wang, Xiaodeng; Zhang, Dingke; Wang, Shuxia; Chen, Shijian

2017-05-01

The design and development of high-efficiency and non-noble-metal hydrogen evolution reaction (HER) electrocatalysts for future clean and renewable energy system has excited significant research interests over the recent years. In this communication, the polymorphic tungsten diphosphide (p-WP2) nanoparticles with mixed monoclinic (α-) and orthorhombic (β-) phases are synthesized by phase-controlled phosphidation route via vacuum capsulation and explored as a novel efficient electrocatalyst towards HER. The p-WP2 catalyst delivers superior performance with excellent stability under both acidic and alkaline conditions over its single phases of α-WP2 and β-WP2. This finding demonstrates that a highly efficient hybrid electrocatalyst can be achieved via precise composition controlling and may open up exciting opportunities for their practical applications toward energy conversion.

Selective detection of dopamine in the presence of ascorbic acid via fluorescence quenching of InP/ZnS quantum dots.

PubMed

Ankireddy, Seshadri Reddy; Kim, Jongsung

2015-01-01

Dopamine is a neurotransmitter of the catecholamine family and has many important roles, especially in human brain. Several diseases of the nervous system, such as Parkinson's disease, attention deficit hyperactivity disorder, restless legs syndrome, are believed to be related to deficiency of dopamine. Several studies have been performed to detect dopamine by using electrochemical analysis. In this study, quantum dots (QDs) were used as sensing media for the detection of dopamine. The surface of the QDs was modified with l-cysteine by coupling reaction to increase the selectivity of dopamine. The fluorescence of cysteine-capped indium phosphide/zinc sulfide QDs was quenched by dopamine with various concentrations in the presence of ascorbic acid. This method shows good selectivity for dopamine detection, and the detection limit was 5 nM.

Surface passivation of InP solar cells with InAlAs layers

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Flood, Dennis J.; Landis, Geoffrey A.

1993-01-01

The efficiency of indium phosphide solar cells is limited by high values of surface recombination. The effect of a lattice-matched In(0.52)Al(0.48)As window layer material for InP solar cells, using the numerical code PC-1D is investigated. It was found that the use of InAlAs layer significantly enhances the p(+)n cell efficiency, while no appreciable improvement is seen for n(+)p cells. The conduction band energy discontinuity at the heterojunction helps in improving the surface recombination. An optimally designed InP cell efficiency improves from 15.4 percent to 23 percent AMO for a 10 nm thick InAlAs layer. The efficiency improvement reduces with increase in InAlAs layer thickness, due to light absorption in the window layer.

Hybrid photonic crystal cavity and waveguide for coupling to diamond NV-centers.

PubMed

Barclay, Paul E; Fu, Kai-Mei; Santori, Charles; Beausoleil, Raymond G

2009-06-08

A design for an ultra-high Q photonic crystal nanocavity engineered to interact with nitrogen-vacancy (NV) centers located near the surface of a single crystal diamond sample is presented. The structure is based upon a nanowire photonic crystal geometry, and consists of a patterned high refractive index thin film, such as gallium phosphide (GaP), supported by a diamond substrate. The nanocavity supports a mode with quality factor Q > 1.5 x 10(6) and mode volume V < 0.52(lambda/nGaP)(3), and promises to allow Purcell enhanced collection of spontaneous emission from an NV located more than 50 nm below the diamond surface. The nanowire photonic crystal waveguide can be used to efficiently couple light into and out of the cavity, or as an efficient broadband collector of NV phonon sideband emission. The proposed structures can be fabricated using existing materials and processing techniques.

Ab-initio study of structural, electronic, and transport properties of zigzag GaP nanotubes.

PubMed

Srivastava, Anurag; Jain, Sumit Kumar; Khare, Purnima Swarup

2014-03-01

Stability and electronic properties of zigzag (3 ≤ n ≤ 16) gallium phosphide nanotubes (GaP NTs) have been analyzed by employing a systematic ab-intio approach based on density functional theory using generalized gradient approximation with revised Perdew Burke Ernzerhoff type parameterization. Diameter dependence of bond length, buckling, binding energy, and band gap has been investigated and the analysis shows that the bond length and buckling decreases with increasing diameter of the tube, highest binding energy of (16, 0) confirms this as the most stable amongst all the NTs taken into consideration. The present GaP NTs shows direct band gap and it increases with diameter of the tubes. Using a two probe model for (4, 0) NT the I-V relationship shows an exponential increase in current on applying bias voltage beyond 1.73 volt.

Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

DOE PAGES

Greenaway, Ann L.; Bachman, Benjamin F.; Boucher, Jason W.; ...

2018-01-12

Ga 1–xIn xP is a technologically important III–V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga 1–xIn xP by water-vapor-mediated close-spaced vapor transport. Because growth of III–V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of ~7000 ppm in H 2 at 850 °C affords smooth films with electron mobility of 1070 cm 2 V –1 s –1 andmore » peak internal quantum efficiency of ~90% for carrier collection in a nonaqueous photoelectrochemical test cell.« less

Photoluminescence of Gallium Phosphide-Based Nanostructures with Germanium Quantum Dots, Grown by Liquid-Phase Epitaxy

NASA Astrophysics Data System (ADS)

Maronchuk, I. I.; Sanikovich, D. D.; Velchenko, A. A.

2017-11-01

We have used liquid-phase epitaxy with pulsed substrate cooling using two structural designs to grow samples of nanoheteroepitaxial structures with Ge quantum dots in a GaP matrix on Si substrates. We have measured the photoluminescence spectra of the samples at temperatures of 77 K and 300 K with excitation by laser emission at λ = 4880 Å and 5145 Å. We draw conclusions concerning the factors influencing the spectrum and intensity of emission for nanostructures with quantum dots. It was found that in order to reduce nonradiative recombination in multilayer p-n structures, we need to create quantum dot arrays inside p and n regions rather than in the central portion of the depletion layer of the p-n junction. We show that the theoretical energies for Ge quantum dots of the calculated sizes are comparable with the energies of their photoluminescence maxima.

Flat-panel video resolution LED display system

NASA Astrophysics Data System (ADS)

Wareberg, P. G.; Kennedy, D. I.

The system consists of a 128 x 128 element X-Y addressable LED array fabricated from green-emitting gallium phosphide. The LED array is interfaced with a 128 x 128 matrix TV camera. Associated electronics provides for seven levels of grey scale above zero with a grey scale ratio of square root of 2. Picture elements are on 0.008 inch centers resulting in a resolution of 125 lines-per-inch and a display area of approximately 1 sq. in. The LED array concept lends itself to modular construction, permitting assembly of a flat panel screen of any desired size from 1 x 1 inch building blocks without loss of resolution. A wide range of prospective aerospace applications exist extending from helmet-mounted systems involving small dedicated arrays to multimode cockpit displays constructed as modular screens. High-resolution LED arrays are already used as CRT replacements in military film-marking reconnaissance applications.

High-Performance Rh 2 P Electrocatalyst for Efficient Water Splitting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, Haohong; Li, Dongguo; Tang, Yan

2017-04-05

The search for active, stable, and cost-efficient electrocatalysts for hydrogen production via water splitting could make a substantial impact on energy technologies that do not rely on fossil fuels. Here we report the synthesis of rhodium phosphide electrocatalyst with low metal loading in the form of nanocubes (NCs) dispersed in high-surface-area carbon (Rh2P/C) by a facile solvo-thermal approach. The Rh2P/C NCs exhibit remarkable performance for hydrogen evolution reaction and oxygen evolution reaction compared to Rh/C and Pt/C catalysts. The atomic structure of the Rh2P NCs was directly observed by annular dark-field scanning transmission electron microscopy, which revealed a phosphorus-rich outermostmore » atomic layer. Combined experimental and computational studies suggest that surface phosphorus plays a crucial role in determining the robust catalyst properties.« less

Thermal Effects That Arise upon Different Heat Treatments in Austenitic Steels Alloyed with Titanium and Phosphorus

NASA Astrophysics Data System (ADS)

Arbuzov, V. L.; Berger, I. F.; Bobrovskii, V. I.; Voronin, V. I.; Danilov, S. E.; Kazantsev, V. A.; Kataev, N. V.; Sagaradze, V. V.

2018-04-01

Structural and microstructural changes that arise in the course of the heat treatment of Cr-Ni-Mo austenitic stainless steels with different concentrations of titanium and phosphorus have been studied. It has been found that the alloying with phosphorus decreases the lattice parameter of these steels. The phosphorus contribution to this effect is 0.015 ± 0.002 Å/at %. Aging at a temperature of 670 K for about 20 h leads to the precipitation of dispersed needle-like particles, which are most likely to be iron phosphides. In the temperature range of 700-800 K, in austenitic steels, the atomic separation of the solid solution occurs, the intensity of which decreases upon alloying with titanium or phosphorus at concentrations of 1.0 and 0.1 wt %, respectively. At higher temperatures (about 950 K), the formed precipitates of the Ni3Ti (γ') phase increase in size to 7-10 nm.

Laser diode with thermal conducting, current confining film

NASA Technical Reports Server (NTRS)

Hawrylo, Frank Z. (Inventor)

1980-01-01

A laser diode formed of a rectangular parallelopiped body of single crystalline semiconductor material includes regions of opposite conductivity type indium phosphide extending to opposite surfaces of the body. Within the body is a PN junction at which light can be generated. A stripe of a conductive material is on the surface of the body to which the P type region extends and forms an ohmic contact with the P type region. The stripe is spaced from the side surfaces of the body and extends to the end surfaces of the body. A film of germanium is on the portions of the surface of the P type region which is not covered by the conductive stripe. The germanium film serves to conduct heat from the body and forms a blocking junction with the P type region so as to confine the current through the body, across the light generating PN junction, away from the side surfaces of the body.

Multi-photon absorption limits to heralded single photon sources

PubMed Central

Husko, Chad A.; Clark, Alex S.; Collins, Matthew J.; De Rossi, Alfredo; Combrié, Sylvain; Lehoucq, Gaëlle; Rey, Isabella H.; Krauss, Thomas F.; Xiong, Chunle; Eggleton, Benjamin J.

2013-01-01

Single photons are of paramount importance to future quantum technologies, including quantum communication and computation. Nonlinear photonic devices using parametric processes offer a straightforward route to generating photons, however additional nonlinear processes may come into play and interfere with these sources. Here we analyse spontaneous four-wave mixing (SFWM) sources in the presence of multi-photon processes. We conduct experiments in silicon and gallium indium phosphide photonic crystal waveguides which display inherently different nonlinear absorption processes, namely two-photon (TPA) and three-photon absorption (ThPA), respectively. We develop a novel model capturing these diverse effects which is in excellent quantitative agreement with measurements of brightness, coincidence-to-accidental ratio (CAR) and second-order correlation function g(2)(0), showing that TPA imposes an intrinsic limit on heralded single photon sources. We build on these observations to devise a new metric, the quantum utility (QMU), enabling further optimisation of single photon sources. PMID:24186400

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Pei; Wang, Yonggang; Wang, Liping

Cubic (space group: Fm3¯m) iridium phosphide, Ir 2P, has been synthesized at high pressure and high temperature. Angle-dispersive synchrotron X-ray diffraction measurements on Ir 2P powder using a diamond-anvil cell at room temperature and high pressures (up to 40.6 GPa) yielded a bulk modulus of B 0 = 306(6) GPa and its pressure derivative B 0'= 6.4(5). Such a high bulk modulus attributed to the short and strongly covalent Ir-P bonds as revealed by first – principles calculations and three-dimensionally distributed [IrP 4] tetrahedron network. Indentation testing on a well–sintered polycrystalline sample yielded the hardness of 11.8(4) GPa. Relatively lowmore » shear modulus of ~64 GPa from theoretical calculations suggests a complicated overall bonding in Ir 2P with metallic, ionic, and covalent characteristics. Additionally, a spin glass behavior is indicated by magnetic susceptibility measurements.« less

A study to investigate the chemical stability of gallium phosphate oxide/gallium arsenide phosphide

NASA Technical Reports Server (NTRS)

Kuhlman, G. J.

1979-01-01

The elemental composition with depth into the oxide films was examined using secondary ion mass spectrometry. Results indicate that the layers are arsenic-deficient through the bulk of the oxide and arsenic-rich near both the oxide surface and the oxide-semiconductor interface region. Phosphorus is incorporated into the oxide in an approximately uniform manner. The MIS capacitor structures exhibited deep-depletion characteristics and hysteresis indicative of electron trapping at the oxide-semiconductor interface. Post-oxidation annealing of the films in argon or nitrogen generally results in slightly increased dielectric leakage currents and decreased C-V hysteresis effects, and is associated with arsenic loss at the oxide surface. The results of bias-temperature stress experiments indicate that the major instability effects are due to changes in the electron trapping behavior. No changes were observed in the elemental profiles following electrical stressing, indicating that the grown films are chemically stable under device operating conditions.

Prospects of poisoning - a multi facet study.

PubMed

Mishra, Pradeep K; Kulkarni, Rashmi; Sane, Mandar R; Deshpande, Ajit; Kushwah, Manish

2016-01-01

Aim of the study is to find out demographic profile, clinical characteristics and analysis of poison in clinical set up. The study carried out in Sri Aurobindo Medical College and PG Institute Indore, Madhya Pradesh. Total 75 cases of poisoning were studied for demographic profile, vitals (BP, pulse, heart rate, pupils, etc.), clinical features (such as vomiting, salivation, consciousness, etc.), type of poison and its analysis. Results: Poisoning was more common in cases between 15 and 25 years of age, in males than in females and in Hindu religion. Poisoning cases were predominantly from rural areas and in married people. Majority of cases were discharged after proper treatment and counseling. Altered vitals and clinical features were found in most of the cases. Organophosphate and aluminum phosphide compound were evaluated in most of the cases. Conclusions: Preventive measures should be applied through educating people, proper counseling, promoting poison information centers, and introducing separate toxicological units in hospitals.

Nanocrystal doped matrixes

DOEpatents

Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan

2010-01-12

Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

Water-Vapor-Mediated Close-Spaced Vapor Transport Growth of Epitaxial Gallium Indium Phosphide Films on Gallium Arsenide Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenaway, Ann L.; Bachman, Benjamin F.; Boucher, Jason W.

Ga 1–xIn xP is a technologically important III–V ternary semiconductor widely utilized in commercial and record-efficiency solar cells. We report the growth of Ga 1–xIn xP by water-vapor-mediated close-spaced vapor transport. Because growth of III–V semiconductors in this system is controlled by diffusion of metal oxide species, we find that congruent transport from the mixed powder source requires complete annealing to form a single alloy phase. Growth from a fully alloyed source at water vapor concentrations of ~7000 ppm in H 2 at 850 °C affords smooth films with electron mobility of 1070 cm 2 V –1 s –1 andmore » peak internal quantum efficiency of ~90% for carrier collection in a nonaqueous photoelectrochemical test cell.« less

Chip-based quantum key distribution

NASA Astrophysics Data System (ADS)

Sibson, P.; Erven, C.; Godfrey, M.; Miki, S.; Yamashita, T.; Fujiwara, M.; Sasaki, M.; Terai, H.; Tanner, M. G.; Natarajan, C. M.; Hadfield, R. H.; O'Brien, J. L.; Thompson, M. G.

2017-02-01

Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip--monolithically integrated devices using components and manufacturing processes from the telecommunications industry. We use the reconfigurability of these devices to demonstrate three prominent QKD protocols--BB84, Coherent One Way and Differential Phase Shift--with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, pave the way for successfully integrating QKD into future telecommunications networks.

A monolithic integrated photonic microwave filter

NASA Astrophysics Data System (ADS)

Fandiño, Javier S.; Muñoz, Pascual; Doménech, David; Capmany, José

2017-02-01

Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.

Confined Molybdenum Phosphide in P-Doped Porous Carbon as Efficient Electrocatalysts for Hydrogen Evolution.

PubMed

Li, Ji-Sen; Zhang, Shuai; Sha, Jing-Quan; Wang, Hao; Liu, Ming-Zhu; Kong, Ling-Xin; Liu, Guo-Dong

2018-05-09

Highly efficient electrocatalysts for hydrogen evolution reactions (HER) are crucial for electrochemical water splitting, where high-cost and low-abundance Pt-based materials are the benchmark catalysts for HER. Herein, we report the fabrication of MoP nanoparticles confined in P-doped porous carbon (MoP@PC) via a metal-organic framework-assisted route for the first time. Remarkably, due to the synergistic effects of MoP nanocrystals, P dopant, and porous carbon, the resulting MoP@PC composite exhibits superior HER catalytic activity with an onset overpotential of 97 mV, a Tafel slope of 59.3 mV dec -1 , and good long-term durability, which compares to those of most reported MoP-based HER catalysts. Most importantly, the work opens a new route in the development of high-performance nonprecious HER electrocatalysts derived from MOFs.

Radiation-acoustic treatment of gallium phosphide light diodes

NASA Astrophysics Data System (ADS)

Tartachnik, Volodimir P.; Gontaruk, Olexsandr M.; Vernydub, Roman M.; Kryvutenko, Anatoly M.; Olikh, Yaroslav M.; Opilat, Vitalij Y.; Petrenko, Igor V.; Pinkovska, Myroslava B.

1999-11-01

The ultrasound influence on the defects of technological and radiation origin of GaP light diodes has been investigated. GaP light diodes were treated by ultrasound wave in different operating modes. Electroluminescence spectra were measured at room and low temperatures, integrated luminosity of devices was checked by solar cell. In order to find out the radiation field influence on non-equilibrium defects of acoustic origin samples were irradiated at room temperature by gamma rays of Co60. It has been discovered that in GaP light diodes treated by ultrasound unstable at room temperature dislocation networks occur at the volume of crystal. Ultrasound dose increase causes the creation of complex defects with high relaxation time and appearing of a part of more mobile defect,s which relax quicker. The nature of effects discovered has been discussed. The method of the emissive capacity restoring of samples degraded after irradiation have been proposed.

Synthesis, structure, and optoelectronic properties of II-IV-V 2 materials

DOE PAGES

Martinez, Aaron D.; Fioretti, Angela N.; Toberer, Eric S.; ...

2017-03-07

II-IV-V 2 materials offer the promise of enhanced functionality in optoelectronic devices due to their rich ternary chemistry. In this review, we consider the potential for new optoelectronic devices based on nitride, phosphide, and arsenide II-IV-V 2 materials. As ternary analogs to the III-V materials, these compounds share many of the attractive features that have made the III-Vs the basis of modern optoelectronic devices (e.g. high mobility, strong optical absorption). Control of cation order parameter in the II-IV-V 2 materials can produce significant changes in optoelectronic properties at fixed chemical composition, including decoupling band gap from lattice parameter. Recent progressmore » has begun to resolve outstanding questions concerning the structure, dopability, and optical properties of the II-IV-V 2 materials. Furthermore, remaining research challenges include growth optimization and integration into heterostructures and devices.« less

Fabrication of InP-pentacene inorganic-organic hybrid heterojunction using MOCVD grown InP for photodetector application

NASA Astrophysics Data System (ADS)

Sarkar, Kalyan Jyoti; Pal, B.; Banerji, P.

2018-04-01

We fabricated inorganic-organic hybrid heterojunction between indium phosphide (InP) and pentacene for photodetector application. InP layer was grown on n-Si substrate by atmospheric pressure metal organic chemical vapour deposition (MOCVD) technique. Morphological properties of InP and pentacene thin film were characterized by atomic force microscopy (AFM). Current-voltage characteristics were investigated in dark and under illumination condition at room temperature. During illumination, different wavelengths of visible and infrared light source were employed to perform the electrical measurement. Enhancement of photocurrent was observed with decreasing in wavelength of incident photo radiation. Ideality factor was found to be 1.92. High rectification ratio of 225 was found at ± 3 V in presence of infrared light source. This study provides new insights of inorganic-organic hybrid heterojunction for broadband photoresponse in visible to near infrared (IR) region under low reverse bias condition.

Large-Area Direct Hetero-Epitaxial Growth of 1550-nm InGaAsP Multi-Quantum-Well Structures on Patterned Exact-Oriented (001) Silicon Substrates by Metal Organic Chemical Vapor Deposition

NASA Astrophysics Data System (ADS)

Megalini, Ludovico; Cabinian, Brian C.; Zhao, Hongwei; Oakley, Douglas C.; Bowers, John E.; Klamkin, Jonathan

2018-02-01

We employ a simple two-step growth technique to grow large-area 1550-nm laser structures by direct hetero-epitaxy of III-V compounds on patterned exact-oriented (001) silicon (Si) substrates by metal organic chemical vapor deposition. Densely-packed, highly uniform, flat and millimeter-long indium phosphide (InP) nanowires were grown from Si v-grooves separated by silicon dioxide (SiO2) stripes with various widths and pitches. Following removal of the SiO2 patterns, the InP nanowires were coalesced and, subsequently, 1550-nm laser structures were grown in a single overgrowth without performing any polishing for planarization. X-ray diffraction, photoluminescence, atomic force microscopy and transmission electron microscopy analyses were used to characterize the epitaxial material. PIN diodes were fabricated and diode-rectifying behavior was observed.

Chip-based quantum key distribution

PubMed Central

Sibson, P.; Erven, C.; Godfrey, M.; Miki, S.; Yamashita, T.; Fujiwara, M.; Sasaki, M.; Terai, H.; Tanner, M. G.; Natarajan, C. M.; Hadfield, R. H.; O'Brien, J. L.; Thompson, M. G.

2017-01-01

Improvement in secure transmission of information is an urgent need for governments, corporations and individuals. Quantum key distribution (QKD) promises security based on the laws of physics and has rapidly grown from proof-of-concept to robust demonstrations and deployment of commercial systems. Despite these advances, QKD has not been widely adopted, and large-scale deployment will likely require chip-based devices for improved performance, miniaturization and enhanced functionality. Here we report low error rate, GHz clocked QKD operation of an indium phosphide transmitter chip and a silicon oxynitride receiver chip—monolithically integrated devices using components and manufacturing processes from the telecommunications industry. We use the reconfigurability of these devices to demonstrate three prominent QKD protocols—BB84, Coherent One Way and Differential Phase Shift—with performance comparable to state-of-the-art. These devices, when combined with integrated single photon detectors, pave the way for successfully integrating QKD into future telecommunications networks. PMID:28181489

High performance InP JFETs grown by MOCVD using tertiarybutylphosphine

NASA Astrophysics Data System (ADS)

Hashemi, M. M.; Shealy, J. B.; Corvini, P. J.; Denbaars, S. P.; Mishra, U. K.

1994-02-01

Indium phosphide channel junction field effect transistors were fabricated by metalorganic chemical vapor deposition using tertiarybulylphosphine (TBP) as the alternative source for phosphine. At growth temperatures of 600°C, InP with specular surface morphology and mobilities as high as 61000 cm2/V s at 77Khas been achieved using trimethylindium and TBP. To improve device isolation, pinch-off characteristics, and output transconductance, we employ a high resistivity (1 × 108 Ω-cm) semi-insulating InP buffer layer using ferrocene as the Fe-dopant. Devices with gate lengths of 1 urn exhibit very high extrinsic transconductance of 130 mS/mm, gate-drain breakdown voltage exceeding 20 V, maximum current density of >450 mA/mm with record high fT and fmax of 15 GHz and 35 GHz, respectively. These results indicate: that InP JFETs are promising electronic devices for microwave power amplification, and that TBP is capable of device quality materials.

Chalcogenide and pnictide nanocrystals from the silylative deoxygenation of metal oxides

DOE PAGES

Lin, Chia-Cheng; Tan, Shannon J.; Vela, Javier

2017-09-11

Transition metal chalcogenide and pnictide nanocrystals are of interest for optoelectronic and catalytic applications. In this paper, we present a generalized route to the synthesis of these materials from the silylative deoxygenation of metal oxides with trimethylsilyl reagents. Specific nanophases produced in this way include Ni 3S 2, Ni 5Se 5, Ni 2P, Co 9S 8, Co 3Se 4, CoP, Co 2P, and heterobimetallic (Ni/Co) 9S 8. The resulting chalcogenide nanocrystals are hollow, likely due to differential rates of ion diffusion during the interfacial phase transformation reaction (Kirkendall-type effect). In contrast, the phosphide nanocrystals are solid, likely because they formmore » at higher reaction temperatures. Finally, in all cases, simultaneous partial decomposition of the deoxygenating silyl reagent produces a coating of amorphous silica around the newly formed nanocrystals, which could impact their stability and recyclability.« less

Selective detection of dopamine in the presence of ascorbic acid via fluorescence quenching of InP/ZnS quantum dots

PubMed Central

Ankireddy, Seshadri Reddy; Kim, Jongsung

2015-01-01

Dopamine is a neurotransmitter of the catecholamine family and has many important roles, especially in human brain. Several diseases of the nervous system, such as Parkinson’s disease, attention deficit hyperactivity disorder, restless legs syndrome, are believed to be related to deficiency of dopamine. Several studies have been performed to detect dopamine by using electrochemical analysis. In this study, quantum dots (QDs) were used as sensing media for the detection of dopamine. The surface of the QDs was modified with l-cysteine by coupling reaction to increase the selectivity of dopamine. The fluorescence of cysteine-capped indium phosphide/zinc sulfide QDs was quenched by dopamine with various concentrations in the presence of ascorbic acid. This method shows good selectivity for dopamine detection, and the detection limit was 5 nM. PMID:26347250

Synthesis, characterization and assembly of metal pnictide nanoparticles, and evaluation of their physicochemical (catalytic, magnetic, and semiconducting) properties

NASA Astrophysics Data System (ADS)

Senevirathne, Keerthisinghe

Synthesis of transition metal phosphide (Ni2P) and arsenide (MnAs) discrete nanoparticles was conducted by following a solution-phase arrested precipitation route and the size- and structure-dependent physicochemical properties of these materials were explored. Furthermore, the assembly of metal phosphide nanoparticles into a network structure via a sol-gel process and the evaluation of their structure related properties also was conducted. The surface ligation chemistry of unsupported Ni2P nanoparticles prepared by arrested precipitation was found to strongly impact the structural integrity and the hydrodesulfurization (HDS) catalytic activity of Ni 2P nanoparticles. The HDS activity of unsupported surface modified Ni2P nanoparticles is higher than that of unsupported Ni2P prepared by temperature programmed reduction (TPR) but considerably lower than silica-supported Ni2P prepared by TPR. However, by supporting the pre-formed Ni 2P nanoparticles on silica, activity comparable to that of silica-supported Ni2P prepared by TPR can be achieved. The synthetic control offered by the Ni2P nanoparticle preparation, not achieved by TPR methods, is expected to enable a systematic study of particle size and shape effects on HDS activity. By using arrested precipitation reactions, for the first time, discrete and dispersible MnAs nanoparticles have been prepared and their magnetic properties evaluated. Syntheses were developed to target both the thermodynamically stable alpha-type (hexagonal) and the metastable beta-type (orthorhombic) MnAs nanoparticles. Surprisingly, both types of ˜25 nm particles exhibit nearly identical ferromagnetic behavior with blocking temperatures, T B, in the region ˜275-310 K, TC's of 315 K and room temperature coercivities of HC ˜ 190-320 Oe. No evidence of the expected structural transition from alpha to beta-MnAs at TC is observed. Oxidative sol-gel assembly of nanoparticles to make nanoparticulate gels was successfully employed to Ni2P nanoparticles, and further extended to MnP and InP nanoparticles, for the first time. The gels were transformed into highly porous, high surface area (175-270 m2/g) 3-D structures (aerogels) via CO2 supercritical drying. Relative to discrete nanoparticles, Ni2P aerogels are less active to HDS, MnP aerogels have similar magnetic properties, and InP aerogels exhibit a greater degree of quantum confinement.

Integration of Indium Phosphide Based Devices with Flexible Substrates

NASA Astrophysics Data System (ADS)

Chen, Wayne Huai

2011-12-01

Flexible substrates have many advantages in applications where bendability, space, or weight play important roles or where rigid circuits are undesirable. However, conventional flexible thin film transistors are typically characterized as having low carrier mobility as compared to devices used in the electronics industry. This is in part due to the limited temperature tolerance of plastic flexible substrates, which commonly reduces the highest processing temperature to below 200°C. Common approaches of implementation include low temperature deposition of organic, amorphous, or polycrystalline semiconductors, all of which result in carrier mobility well below 100 cm2V -1s-1. High quality, single crystalline III-V semiconductors such as indium phosphide (InP), on the other hand, have carrier mobility well over 1000 cm 2V-1s-1 at room temperature, depending on carrier concentration. Recently, the ion-cut process has been used in conjunction with wafer bonding to integrate thin layers of III-V material onto silicon for optoelectronic applications. This approach has the advantage of high scalability, reusability of the initial III-V substrate, and the ability to tailor the location (depth) of the layer splitting. However, the transferred substrate usually suffers from hydrogen implantation damage. This dissertation demonstrates a new approach to enable integration of InP with various substrates, called the double-flip transfer process. The process combines ion-cutting with adhesive bonding. The problem of hydrogen implantation was overcome by patterned ion-cut transfer. In this type of transfer, areas of interest are shielded from implantation but still transferred by surrounding implanted regions. We found that patterned ion-cut transfer is strongly dependent upon crystal orientation and that using cleavage-plane oriented donors can be beneficial in transferring large areas of high quality semiconductor material. InP-based devices were fabricated to demonstrate the transfer process and test functionality following transfer. Passive devices (photodetectors) as well as active transistors were transferred and fabricated on various substrates. The transferred device layers were either implanted through with a blanket implant or protected with an ion-mask during implantation. Results demonstrate the viability of the double-flip ion-cut process in achieving very high electron mobility (˜2800 cm2V-1s-1) transistors on plastic flexible substrates.

Lattice Matched Iii-V IV Semiconductor Heterostructures: Metalorganic Chemical Vapor Deposition and Remote Plasma Enhanced Chemical Vapor Deposition.

NASA Astrophysics Data System (ADS)

Choi, Sungwoo

1992-01-01

This thesis describes the growth and characterization of wide gap III-V compound semiconductors such as aluminum gallium arsenide (Al_{rm x} Ga_{rm 1-x}As), gallium nitride (GaN), and gallium phosphide (GaP), deposited by the metalorganic chemical vapor deposition (MOCVD) and remote plasma enhanced chemical vapor deposition (Remote PECVD). In the first part of the thesis, the optimization of GaAs and Al_{rm x}Ga _{rm 1-x}As hetero -epitaxial layers on Ge substrates is described in the context of the application in the construction of cascade solar cells. The emphasis on this study is on the trade-offs in the choice of the temperature related to increasing interdiffusion/autodoping and increasing perfection of the epilayer with increasing temperature. The structural, chemical, optical, and electrical properties of the heterostructures are characterized by x-ray rocking curve measurement, scanning electron microscopy (SEM), electron beam induced current (EBIC), cross-sectional transmission electron microscopy (X-TEM), Raman spectroscopy, secondary ion mass spectrometry (SIMS), and steady-state and time-resolved photoluminescence (PL). Based on the results of this work the optimum growth temperature is 720^circC. The second part of the thesis describes the growth of GaN and GaP layers on silicon and sapphire substrates and the homoepitaxy of GaP by remote PECVD. I have designed and built an ultra high vacuum (UHV) deposition system which includes: the gas supply system, the pumping system, the deposition chamber, the load-lock chamber, and the waste disposal system. The work on the deposition of GaN on Si and sapphire focuses onto the understanding of the growth kinetics. In addition, Auger electron spectroscopy (AES) for surface analysis, x-ray diffraction methods and microscopic analyses using SEM and TEM for structural characterization, infrared (IR) and ultraviolet (UV) absorption measurements for optical characterization, and electrical characterization results on the GaN films are presented. In the deposition GaP thin films by remote PECVD, trimethylgallium and in-situ generated phosphine precursors are employed as source gases which permits homo- and heteroepitaxial growth as substrate temperature of 590-620^ circC. Also, the growth kinetics of gallium phosphide is discussed. As in the case of GaN, the surface, structural, chemical, optical, and electrical properties are characterized and the results are discussed.

Development of cadmium-free quantum dot for intracellular labelling through electroporation or lipid-calcium-phosphate

NASA Astrophysics Data System (ADS)

Liu, Ying-Feng; Hung, Wei-Ling; Hou, Tzh-Yin; Huang, Hsiu-Ying; Lin, Cheng-An J.

2016-04-01

Traditional fluorescent labelling techniques has severe photo-bleaching problem such as organic dyes and fluorescent protein. Quantum dots made up of traditional semiconductor (CdSe/ZnS) material has sort of biological toxicity. This research has developed novel Cd-free quantum dots divided into semiconductor (Indium phosphide, InP) and noble metal (Gold). Former has lower toxicity compared to traditional quantum dots. Latter consisting of gold (III) chloride (AuCl3) and toluene utilizes sonochemical preparation and different stimulus to regulate fluorescent wavelength. Amphoteric macromolecule surface technology and ligand Exchange in self-Assembled are involved to develop hydrophilic nanomaterials which can regulate the number of grafts per molecule of surface functional groups. Calcium phosphate (CaP) nanoparticle (NP) with an asymmetric lipid bilayer coating technology developed for intracellular delivery and labelling has synthesized Cd-free quantum dots possessing high brightness and multi-fluorescence successfully. Then, polymer coating and ligand exchange transfer to water-soluble materials to produce liposome nanomaterials as fluorescent probes and enhancing medical applications of nanotechnology.

Comparison of GaP nanowires grown from Au and Sn vapor-liquid-solid catalysts as photoelectrode materials

NASA Astrophysics Data System (ADS)

Lee, Sudarat; Wen, Wen; Cheek, Quintin; Maldonado, Stephen

2018-01-01

Gallium phosphide (GaP) nanowire film electrodes have been prepared via solid sublimation of GaP powder using both gold (Au) and tin (Sn) nanoparticles as the vapor-liquid-solid (VLS) catalysts on Si(1 1 1) and GaP(1 1 1)B substrates. The resultant GaP nanowires are compared and contrasted in terms of structures and photoactivity in photoelectrochemical half cells. Raman spectra implicated a difference in the surface condition of the two types of nanowires. Complete wet etching removal of metallic VLS catalysts from the as-prepared GaP nanowires was possible with Sn catalysts but not with Au catalysts. The photoresponses of both Sn- and Au-seeded GaP nanowire films were collected and examined under 100 mW cm-2 white light illumination. Au-seeded nanowire films exhibited strong n-type characteristics when measured in nonaqueous electrolyte with ferrocene/ferricenium as the redox species while Sn-seeded nanowires showed behavior consistent with degenerate n-type doping.

Hybrid indium phosphide-on-silicon nanolaser diode

NASA Astrophysics Data System (ADS)

Crosnier, Guillaume; Sanchez, Dorian; Bouchoule, Sophie; Monnier, Paul; Beaudoin, Gregoire; Sagnes, Isabelle; Raj, Rama; Raineri, Fabrice

2017-04-01

The most-awaited convergence of microelectronics and photonics promises to bring about a revolution for on-chip data communications and processing. Among all the optoelectronic devices to be developed, power-efficient nanolaser diodes able to be integrated densely with silicon photonics and electronics are essential to convert electrical data into the optical domain. Here, we report a demonstration of ultracompact laser diodes based on one-dimensional (1D) photonic crystal (PhC) nanocavities made in InP nanoribs heterogeneously integrated on a silicon-waveguide circuitry. The specific nanorib design enables an efficient electrical injection of carriers in the nanocavity without spoiling its optical properties. Room-temperature continuous-wave (CW) single-mode operation is obtained with a low current threshold of 100 µA. Laser emission at 1.56 µm in the silicon waveguides is obtained with wall-plug efficiencies greater than 10%. This result opens up exciting avenues for constructing optical networks at the submillimetre scale for on-chip interconnects and signal processing.

Chemical and physical insight on the local properties of the phosphides XSiP2 (X = Be, Mg, Cd, Zn and Hg) under pressure: from first principles calculations

NASA Astrophysics Data System (ADS)

Ouahrani, Tarik

2013-09-01

Local properties of the XSiP2 (X = Be, Mg, Cd, Zn and Hg) compounds are revisited through the partition of static thermodynamic properties under pressure. We pay attention to the metallization that occurs when the investigated compounds undergo a phase transition from chalcopyrite to the NaCl structure. Electron localization function analysis shows that the local valence basin attractors values decrease as a function of pressure. As the pressure increases, the tetragonal distortion ( c/ a) diminishes while the degree of ionicity enhances. In addition, by means of atom in molecule approach, atomic-like local compressibility and pressures are analyzed. We found that the basins volumes of the investigated compounds in the NaCl phase have lower compressibilities than those in the chalcopyrite phase. According to the predicted core-valence basins, the phosphorus cation is found to be the more affected by the hydrostatic pressure.

Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

NASA Astrophysics Data System (ADS)

Ko, Wai Son; Bhattacharya, Indrasen; Tran, Thai-Truong D.; Ng, Kar Wei; Adair Gerke, Stephen; Chang-Hasnain, Connie

2016-09-01

Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics. III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7 GHz) and responsivity (9.5 A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. The quantum efficiency-bandwidth product of 105 GHz is the highest for photodetectors on silicon. The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage.

Method of forming thermally stable high-resistivity regions in n-type indium phosphide by oxygen implantation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thompson, P.E.; Dietrich, H.B.

1985-12-12

Objects of this invention are: to form high-temperature stable isolation regions in InP; to provide InP wafers that allow greater flexibility in the design and fabrication of discrete devices; to provide new and improved InP semiconductor devices in n-type InP; to provide high-resisitivity isolation regions in InP; to extend the usefulness of damage-induced isolation in n-type InP by making possible processes in which the isolation implantation precedes the alloying of ohmic contacts; and to provide n-type InP substrates without unwanted conductive layers. The above and other object are realized by an InP wafer comprising a S.I. InP substrate; a n-typemore » InP active layer disposed on the substrate; and oxygen ion implanted isolation regions disposed in the active layer. The S.I. InP dopant may comprise either Fe or Cr.« less

Pressure-induced zigzag phosphorus chain and superconductivity in boron monophosphide.

PubMed

Zhang, Xinyu; Qin, Jiaqian; Liu, Hanyu; Zhang, Shiliang; Ma, Mingzhen; Luo, Wei; Liu, Riping; Ahuja, Rajeev

2015-03-04

We report on the prediction of the zinc-blende structure BP into a novel C2/m phase from 113 to 208 GPa which possesses zigzag phosphorus chain structure, followed by another P42/mnm structure above 208 GPa above using the particle-swarm search method. Strong electron-phonon coupling λ in compressed BP is found, in particular for C2/m phase with the zigzag phosphorus chain, which has the highest λ (0.56-0.61) value among them, leading to its high superconducting critical temperature Tc (9.4 K-11.5 K), which is comparable with the 4.5 K to 13 K value of black phosphorus phase I (orthorhombic, Cmca). This is the first system in the boron phosphides which shows superconductivity from the present theoretical calculations. Our results show that pressure-induced zigzag phosphorus chain in BP exhibit higher superconducting temperature TC, opening a new route to search and design new superconductor materials with zigzag phosphorus chains.

High-performance indium gallium phosphide/gallium arsenide heterojunction bipolar transistors

NASA Astrophysics Data System (ADS)

Ahmari, David Abbas

Heterojunction bipolar transistors (HBTs) have demonstrated the high-frequency characteristics as well as the high linearity, gain, and power efficiency necessary to make them attractive for a variety of applications. Specific applications for which HBTs are well suited include amplifiers, analog-to-digital converters, current sources, and optoelectronic integrated circuits. Currently, most commercially available HBT-based integrated circuits employ the AlGaAs/GaAs material system in applications such as a 4-GHz gain block used in wireless phones. As modern systems require higher-performance and lower-cost devices, HBTs utilizing the newer, InGaP/GaAs and InP/InGaAs material systems will begin to dominate the HBT market. To enable the widespread use of InGaP/GaAs HBTs, much research on the fabrication, performance, and characterization of these devices is required. This dissertation will discuss the design and implementation of high-performance InGaP/GaAs HBTs as well as study HBT device physics and characterization.

Study of the interfacial reactions between a bioactive apatite-mullite glass-ceramic coating and titanium substrates using high angle annular dark field transmission electron microscopy.

PubMed

Stanton, Kenneth T; O'Flynn, Kevin P; Nakahara, Shohei; Vanhumbeeck, Jean-François; Delucca, John M; Hooghan, Bobby

2009-04-01

Glass of generic composition SiO(2) . Al(2)O(3) . P(2)O(5) . CaO . CaF(2) will crystallise predominantly to apatite and mullite upon heat-treatment. Such ceramics are bioactive, osseoconductive, and have a high resistance to fracture. As a result, they are under investigation for use as biomedical device coatings, and in particular for orthopaedic implants. Previous work has shown that the material can be successfully enamelled to titanium with an interfacial reaction zone produced during heat treatment. The present study uses high angle annular dark field transmission electron microscopy (HAADF-TEM) to conduct a detailed examination of this region. Results show evidence of complex interfacial reactions following the diffusion of titanium into an intermediate layer and the production of titanium silicides and titanium phosphides. These results confirm previously hypothesised mechanisms for the bonding of silicate bioceramics with titanium alloys.

Mesoscopic Perovskite Light-Emitting Diodes.

PubMed

Palma, Alessandro Lorenzo; Cinà, Lucio; Busby, Yan; Marsella, Andrea; Agresti, Antonio; Pescetelli, Sara; Pireaux, Jean-Jacques; Di Carlo, Aldo

2016-10-03

Solution-processed hybrid bromide perovskite light-emitting-diodes (PLEDs) represent an attractive alternative technology that would allow overcoming the well-known severe efficiency drop in the green spectrum related to conventional LEDs technologies. In this work, we report on the development and characterization of PLEDs fabricated using, for the first time, a mesostructured layout. Stability of PLEDs is a critical issue; remarkably, mesostructured PLEDs devices tested in ambient conditions and without encapsulation showed a lifetime well-above what previously reported with a planar heterojunction layout. Moreover, mesostructured PLEDs measured under full operative conditions showed a remarkably narrow emission spectrum, even lower than what is typically obtained by nitride- or phosphide-based green LEDs. A dynamic analysis has shown fast rise and fall times, demonstrating the suitability of PLEDs for display applications. Combined electrical and advanced structural analyses (Raman, XPS depth profiling, and ToF-SIMS 3D analysis) have been performed to elucidate the degradation mechanism, the results of which are mainly related to the degradation of the hole-transporting material (HTM) and to the perovskite-HTM interface.

High-efficiency solar cell and method for fabrication

DOEpatents

Hou, Hong Q.; Reinhardt, Kitt C.

1999-01-01

A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD).

Advanced high temperature thermoelectrics for space power

NASA Technical Reports Server (NTRS)

Lockwood, A.; Ewell, R.; Wood, C.

1981-01-01

Preliminary results from a spacecraft system study show that an optimum hot junction temperature is in the range of 1500 K for advanced nuclear reactor technology combined with thermoelectric conversion. Advanced silicon germanium thermoelectric conversion is feasible if hot junction temperatures can be raised roughly 100 C or if gallium phosphide can be used to improve the figure of merit, but the performance is marginal. Two new classes of refractory materials, rare earth sulfides and boron-carbon alloys, are being investigated to improve the specific weight of the generator system. Preliminary data on the sulfides have shown very high figures of merit over short temperature ranges. Both n- and p-type doping have been obtained. Pure boron-carbide may extrapolate to high figure of merit at temperatures well above 1500 K but not lower temperature; n-type conduction has been reported by others, but not yet observed in the JPL program. Inadvertant impurity doping may explain the divergence of results reported.

B 12P 2: Improved Epitaxial Growth and Evaluation of Alpha Irradiation on its Electrical Transport Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frye, Clint D.

The wide bandgap (3.35 eV) semiconductor icosahedral boron phosphide (B 12P 2) has been reported to self-heal from radiation damage from β particles (electrons) with energies up to 400 keV by demonstrating no lattice damage using transmission electron microscopy. This property could be exploited to create radioisotope batteries–semiconductor devices that directly convert the decay energy from a radioisotope to electricity. Such devices potentially have enormous power densities and decades-long lifetimes. To date, the radiation hardness of B 12P 2 has not been characterized by electrical measurements nor have B 12P 2 radioisotope batteries been realized. Therefore, this study was undertakenmore » to evaluate the radiation hardness of B 12P 2 after improving its epitaxial growth, developing ohmic electrical contacts, and reducing the residual impurities. Subsequently, the effects of radiation from a radioisotope on the electrical transport properties of B 12P 2 were tested.« less

PHOTONICS AND NANOTECHNOLOGY Pulsed laser ablation of binary semiconductors: mechanisms of vaporisation and cluster formation

NASA Astrophysics Data System (ADS)

Bulgakov, A. V.; Evtushenko, A. B.; Shukhov, Yu G.; Ozerov, I.; Marin, W.

2010-12-01

Formation of small clusters during pulsed ablation of two binary semiconductors, zinc oxide and indium phosphide, in vacuum by UV, visible, and IR laser radiation is comparatively studied. The irradiation conditions favourable for generation of neutral and charged ZnnOm and InnPm clusters of different stoichiometry in the ablation products are found. The size and composition of the clusters, their expansion dynamics and reactivity are analysed by time-of-flight mass spectrometry. A particular attention is paid to the mechanisms of ZnO and InP ablation as a function of laser fluence, with the use of different ablation models. It is established that ZnO evapourates congruently in a wide range of irradiation conditions, while InP ablation leads to enrichment of the target surface with indium. It is shown that this radically different character of semiconductor ablation determines the composition of the nanostructures formed: zinc oxide clusters are mainly stoichiometric, whereas InnPm particles are significantly enriched with indium.

Hybrid bioinorganic approach to solar-to-chemical conversion.

PubMed

Nichols, Eva M; Gallagher, Joseph J; Liu, Chong; Su, Yude; Resasco, Joaquin; Yu, Yi; Sun, Yujie; Yang, Peidong; Chang, Michelle C Y; Chang, Christopher J

2015-09-15

Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥ 7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion.

A quantum light-emitting diode for the standard telecom window around 1,550 nm.

PubMed

Müller, T; Skiba-Szymanska, J; Krysa, A B; Huwer, J; Felle, M; Anderson, M; Stevenson, R M; Heffernan, J; Ritchie, D A; Shields, A J

2018-02-28

Single photons and entangled photon pairs are a key resource of many quantum secure communication and quantum computation protocols, and non-Poissonian sources emitting in the low-loss wavelength region around 1,550 nm are essential for the development of fibre-based quantum network infrastructure. However, reaching this wavelength window has been challenging for semiconductor-based quantum light sources. Here we show that quantum dot devices based on indium phosphide are capable of electrically injected single photon emission in this wavelength region. Using the biexciton cascade mechanism, they also produce entangled photons with a fidelity of 87 ± 4%, sufficient for the application of one-way error correction protocols. The material system further allows for entangled photon generation up to an operating temperature of 93 K. Our quantum photon source can be directly integrated with existing long distance quantum communication and cryptography systems, and provides a promising material platform for developing future quantum network hardware.

Rapidly reconfigurable high-fidelity optical arbitrary waveform generation in heterogeneous photonic integrated circuits.

PubMed

Feng, Shaoqi; Qin, Chuan; Shang, Kuanping; Pathak, Shibnath; Lai, Weicheng; Guan, Binbin; Clements, Matthew; Su, Tiehui; Liu, Guangyao; Lu, Hongbo; Scott, Ryan P; Ben Yoo, S J

2017-04-17

This paper demonstrates rapidly reconfigurable, high-fidelity optical arbitrary waveform generation (OAWG) in a heterogeneous photonic integrated circuit (PIC). The heterogeneous PIC combines advantages of high-speed indium phosphide (InP) modulators and low-loss, high-contrast silicon nitride (Si₃N₄) arrayed waveguide gratings (AWGs) so that high-fidelity optical waveform syntheses with rapid waveform updates are possible. The generated optical waveforms spanned a 160 GHz spectral bandwidth starting from an optical frequency comb consisting of eight comb lines separated by 20 GHz channel spacing. The Error Vector Magnitude (EVM) values of the generated waveforms were approximately 16.4%. The OAWG module can rapidly and arbitrarily reconfigure waveforms upon every pulse arriving at 2 ns repetition time. The result of this work indicates the feasibility of truly dynamic optical arbitrary waveform generation where the reconfiguration rate or the modulator bandwidth must exceed the channel spacing of the AWG and the optical frequency comb.

High-efficiency solar cell and method for fabrication

DOEpatents

Hou, H.Q.; Reinhardt, K.C.

1999-08-31

A high-efficiency 3- or 4-junction solar cell is disclosed with a theoretical AM0 energy conversion efficiency of about 40%. The solar cell includes p-n junctions formed from indium gallium arsenide nitride (InGaAsN), gallium arsenide (GaAs) and indium gallium aluminum phosphide (InGaAlP) separated by n-p tunnel junctions. An optional germanium (Ge) p-n junction can be formed in the substrate upon which the other p-n junctions are grown. The bandgap energies for each p-n junction are tailored to provide substantially equal short-circuit currents for each p-n junction, thereby eliminating current bottlenecks and improving the overall energy conversion efficiency of the solar cell. Additionally, the use of an InGaAsN p-n junction overcomes super-bandgap energy losses that are present in conventional multi-junction solar cells. A method is also disclosed for fabricating the high-efficiency 3- or 4-junction solar cell by metal-organic chemical vapor deposition (MOCVD). 4 figs.

Photonic crystals possessing multiple Weyl points and the experimental observation of robust surface states

PubMed Central

Chen, Wen-Jie; Xiao, Meng; Chan, C. T.

2016-01-01

Weyl points, as monopoles of Berry curvature in momentum space, have captured much attention recently in various branches of physics. Realizing topological materials that exhibit such nodal points is challenging and indeed, Weyl points have been found experimentally in transition metal arsenide and phosphide and gyroid photonic crystal whose structure is complex. If realizing even the simplest type of single Weyl nodes with a topological charge of 1 is difficult, then making a real crystal carrying higher topological charges may seem more challenging. Here we design, and fabricate using planar fabrication technology, a photonic crystal possessing single Weyl points (including type-II nodes) and multiple Weyl points with topological charges of 2 and 3. We characterize this photonic crystal and find nontrivial 2D bulk band gaps for a fixed kz and the associated surface modes. The robustness of these surface states against kz-preserving scattering is experimentally observed for the first time. PMID:27703140

Nanomaterials derived from metal-organic frameworks

NASA Astrophysics Data System (ADS)

Dang, Song; Zhu, Qi-Long; Xu, Qiang

2018-01-01

The thermal transformation of metal-organic frameworks (MOFs) generates a variety of nanostructured materials, including carbon-based materials, metal oxides, metal chalcogenides, metal phosphides and metal carbides. These derivatives of MOFs have characteristics such as high surface areas, permanent porosities and controllable functionalities that enable their good performance in sensing, gas storage, catalysis and energy-related applications. Although progress has been made to tune the morphologies of MOF-derived structures at the nanometre scale, it remains crucial to further our knowledge of the relationship between morphology and performance. In this Review, we summarize the synthetic strategies and optimized methods that enable control over the size, morphology, composition and structure of the derived nanomaterials. In addition, we compare the performance of materials prepared by the MOF-templated strategy and other synthetic methods. Our aim is to reveal the relationship between the morphology and the physico-chemical properties of MOF-derived nanostructures to optimize their performance for applications such as sensing, catalysis, and energy storage and conversion.

Bandgap Engineering of InP QDs Through Shell Thickness and Composition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dennis, Allison M.; Mangum, Benjamin D.; Piryatinski, Andrei

2012-06-21

Fields as diverse as biological imaging and telecommunications utilize the unique photophysical and electronic properties of nanocrystal quantum dots (NQDs). The development of new NQD compositions promises material properties optimized for specific applications, while addressing material toxicity. Indium phosphide (InP) offers a 'green' alternative to the traditional cadmium-based NQDs, but suffers from extreme susceptibility to oxidation. Coating InP cores with more stable shell materials significantly improves nanocrystal resistance to oxidation and photostability. We have investigated several new InP-based core-shell compositions, correlating our results with theoretical predictions of their optical and electronic properties. Specifically, we can tailor the InP core-shell QDsmore » to a type-I, quasi-type-II, or type-II bandgap structure with emission wavelengths ranging from 500-1300 nm depending on the shell material used (ZnS, ZnSe, CdS, or CdSe) and the thickness of the shell. Single molecule microscopy assessments of photobleaching and blinking are used to correlate NQD properties with shell thickness.« less

Electron-beam induced damage in thin insulating films on compound semiconductors. M.S. Thesis, 1988

NASA Technical Reports Server (NTRS)

Pantic, Dragan M.

1989-01-01

Phosphorus rich plasma enhanced chemical vapor deposition (PECVD) of silicon nitride and silicon dioxide films on n-type indium phosphide (InP) substrates were exposed to electron-beam irradiation in the 5 to 40 keV range for the purpose of characterizing the damage induced in the dielectric. The electron-beam exposure was on the range of 10(exp -7) to 10(exp -3) C/sq cm. The damage to the devices was characterized by capacitance-voltage (C-V) measurements of the metal insulator semiconductor (MIS) capacitors. These results were compared to results obtained for radiation damage of thermal silicon dioxide on silicon (Si) MOS capacitors with similar exposures. The radiation induced damage in the PECVD silicon nitride films on InP was successfully annealed out in an hydrogen/nitrogen (H2/N2) ambient at 400 C for 15 min. The PECVD silicon dioxide films on InP had the least radiation damage, while the thermal silicon dioxide films on Si had the most radiation damage.

Operando Spectroscopic Analysis of CoP Films Electrocatalyzing the Hydrogen-Evolution Reaction

DOE PAGES

Saadi, Fadl H.; Carim, Azhar I.; Drisdell, Walter S.; ...

2017-08-28

Transition metal phosphides exhibit high catalytic activity toward the electrochemical hydrogen-evolution reaction (HER) and resist chemical corrosion in acidic solutions. For example, an electrodeposited CoP catalyst exhibited an overpotential, η of -η < 100 mV at a current density of -10 mA cm -2 in 0.500 M H 2SO 4 (aq). To obtain a chemical description of the material as-prepared and also while effecting the HER in acidic media, such electrocatalyst films were investigated using Raman spectroscopy and X-ray absorption spectroscopy both ex situ as well as under in situ and operando conditions in 0.500 M H 2SO 4 (aq).more » Ex situ analysis using the tandem spectroscopies indicated the presence of multiple ordered and disordered phases that contained both near-zerovalent and oxidized Co species, in addition to reduced and oxygenated P species. Lastly, operando analysis indicated that the active electrocatalyst was primarily amorphous and predominantly consisted of near-zerovalent Co as well as reduced P.« less

III-Vs at Scale: A PV Manufacturing Cost Analysis of the Thin Film Vapor-Liquid-Solid Growth Mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Maxwell; Horowitz, Kelsey; Woodhouse, Michael

The authors present a manufacturing cost analysis for producing thin-film indium phosphide modules by combining a novel thin-film vapor-liquid-solid (TF-VLS) growth process with a standard monolithic module platform. The example cell structure is ITO/n-TiO2/p-InP/Mo. For a benchmark scenario of 12% efficient modules, the module cost is estimated to be $0.66/W(DC) and the module cost is calculated to be around $0.36/W(DC) at a long-term potential efficiency of 24%. The manufacturing cost for the TF-VLS growth portion is estimated to be ~$23/m2, a significant reduction compared with traditional metalorganic chemical vapor deposition. The analysis here suggests the TF-VLS growth mode could enablemore » lower-cost, high-efficiency III-V photovoltaics compared with manufacturing methods used today and open up possibilities for other optoelectronic applications as well.« less

Hybrid bioinorganic approach to solar-to-chemical conversion

PubMed Central

Nichols, Eva M.; Gallagher, Joseph J.; Liu, Chong; Su, Yude; Resasco, Joaquin; Yu, Yi; Sun, Yujie; Yang, Peidong; Chang, Michelle C. Y.; Chang, Christopher J.

2015-01-01

Natural photosynthesis harnesses solar energy to convert CO2 and water to value-added chemical products for sustaining life. We present a hybrid bioinorganic approach to solar-to-chemical conversion in which sustainable electrical and/or solar input drives production of hydrogen from water splitting using biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane. Using platinum or an earth-abundant substitute, α-NiS, as biocompatible hydrogen evolution reaction (HER) electrocatalysts and Methanosarcina barkeri as a biocatalyst for CO2 fixation, we demonstrate robust and efficient electrochemical CO2 to CH4 conversion at up to 86% overall Faradaic efficiency for ≥7 d. Introduction of indium phosphide photocathodes and titanium dioxide photoanodes affords a fully solar-driven system for methane generation from water and CO2, establishing that compatible inorganic and biological components can synergistically couple light-harvesting and catalytic functions for solar-to-chemical conversion. PMID:26305947

Biobased alkylphenols from lignins via a two-step pyrolysis - Hydrodeoxygenation approach.

PubMed

de Wild, P J; Huijgen, W J J; Kloekhorst, A; Chowdari, R K; Heeres, H J

2017-04-01

Five technical lignins (three organosolv, Kraft and soda lignin) were depolymerised to produce monomeric biobased aromatics, particularly alkylphenols, by a new two-stage thermochemical approach consisting of dedicated pyrolysis followed by catalytic hydrodeoxygenation (HDO) of the resulting pyrolysis oils. Pyrolysis yielded a mixture of guaiacols, catechols and, optionally, syringols in addition to alkylphenols. HDO with heterogeneous catalysts (Ru/C, CoMo/alumina, phosphided NiMO/C) effectively directed the product mixture towards alkylphenols by, among others, demethoxylation. Up to 15wt% monomeric aromatics of which 11wt% alkylphenols was obtained (on the lignin intake) with limited solid formation (<3wt% on lignin oil intake). For comparison, solid Kraft lignin was also directly hydrotreated for simultaneous depolymerisation and deoxygenation resulting in two times more alkylphenols. However, the alkylphenols concentration in the product oil is higher for the two-stage approach. Future research should compare direct hydrotreatment and the two-stage approach in more detail by techno-economic assessments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method of making an icosahedral boride structure

DOEpatents

Hersee, Stephen D.; Wang, Ronghua; Zubia, David; Aselage, Terrance L.; Emin, David

2005-01-11

A method for fabricating thin films of an icosahedral boride on a silicon carbide (SiC) substrate is provided. Preferably the icosahedral boride layer is comprised of either boron phosphide (B.sub.12 P.sub.2) or boron arsenide (B.sub.12 As.sub.2). The provided method achieves improved film crystallinity and lowered impurity concentrations. In one aspect, an epitaxially grown layer of B.sub.12 P.sub.2 with a base layer or substrate of SiC is provided. In another aspect, an epitaxially grown layer of B.sub.12 As.sub.2 with a base layer or substrate of SiC is provided. In yet another aspect, thin films of B.sub.12 P.sub.2 or B.sub.12 As.sub.2 are formed on SiC using CVD or other vapor deposition means. If CVD techniques are employed, preferably the deposition temperature is above 1050.degree. C., more preferably in the range of 1100.degree. C. to 1400.degree. C., and still more preferably approximately 1150.degree. C.

Diffusion lengths in irradiated N/P InP-on-Si solar cells

NASA Technical Reports Server (NTRS)

Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

1995-01-01

Indium phosphide (InP) solar cells are being made on silicon (Si) wafers (InP/Si) to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers compared to InP or germanium (Ge) wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. InP/Si cells have higher absolute efficiency after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells. In this work, base electron diffusion lengths in the N/P cell are extracted from measured AM0 short-circuit photocurrent at various irradiation levels out to an equivalent 1 MeV fluence of 1017 1 MeV electrons/sq cm for a 1 sq cm 12% BOL InP/Si cell. These values are then checked for consistency by comparing measured Voc data with a theoretical Voc model that includes a dark current term that depends on the extracted diffusion lengths.

Intracellular bimodal nanoparticles based on quantum dots for high-field MRI at 21.1 T.

PubMed

Rosenberg, Jens T; Kogot, Joshua M; Lovingood, Derek D; Strouse, Geoffrey F; Grant, Samuel C

2010-09-01

Multimodal, biocompatible contrast agents for high magnetic field applications represent a new class of nanomaterials with significant potential for tracking of fluorescence and MR in vitro and vivo. Optimized for high-field MR applications-including biomedical imaging at 21.1 T, the highest magnetic field available for MRI-these nanoparticles capitalize on the improved performance of chelated Dy(3+) with increasing magnetic field coupled to a noncytotoxic Indium Phosphide/Zinc Sulfide (InP/ZnS) quantum dot that provides fluorescence detection, MR responsiveness, and payload delivery. By surface modifying the quantum dot with a cell-penetrating peptide sequence coupled to an MR contrast agent, the bimodal nanomaterial functions as a self-transfecting high-field MR/optical contrast agent for nonspecific intracellular labeling. Fluorescent images confirm sequestration in perinuclear vesicles of labeled cells, with no apparent cytotoxicity. These techniques can be extended to impart cell selectivity or act as a delivery vehicle for genetic or pharmaceutical interventions. 2010 Wiley-Liss, Inc.

Ultrahigh Responsivity-Bandwidth Product in a Compact InP Nanopillar Phototransistor Directly Grown on Silicon

PubMed Central

Ko, Wai Son; Bhattacharya, Indrasen; Tran, Thai-Truong D.; Ng, Kar Wei; Adair Gerke, Stephen; Chang-Hasnain, Connie

2016-01-01

Highly sensitive and fast photodetectors can enable low power, high bandwidth on-chip optical interconnects for silicon integrated electronics. III-V compound semiconductor direct-bandgap materials with high absorption coefficients are particularly promising for photodetection in energy-efficient optical links because of the potential to scale down the absorber size, and the resulting capacitance and dark current, while maintaining high quantum efficiency. We demonstrate a compact bipolar junction phototransistor with a high current gain (53.6), bandwidth (7 GHz) and responsivity (9.5 A/W) using a single crystalline indium phosphide nanopillar directly grown on a silicon substrate. Transistor gain is obtained at sub-picowatt optical power and collector bias close to the CMOS line voltage. The quantum efficiency-bandwidth product of 105 GHz is the highest for photodetectors on silicon. The bipolar junction phototransistor combines the receiver front end circuit and absorber into a monolithic integrated device, eliminating the wire capacitance between the detector and first amplifier stage. PMID:27659796

Advanced transition metal phosphide materials from single-source molecular precursors

NASA Astrophysics Data System (ADS)

Colson, Adam Caleb

In this thesis, the feasibility of employing organometallic single-source precursors in the preparation of advanced transition metal pnictide materials such as colloidal nanoparticles and films has been investigated. In particular, the ternary FeMnP phase was targeted as a model for preparing advanced heterobimetallic phosphide materials, and the iron-rich Fe3P phase was targeted due to its favorable ferromagnetic properties as well as the fact that the preparation of advanced Fe3P materials has been elusive by commonly used methods. Progress towards the synthesis of advanced Fe2--xMn xP nanomaterials and films was facilitated by the synthesis of the novel heterobimetallic complexes FeMn(CO)8(mu-PR1R 2) (R1 = H, R2 = H or R1 = H, R2 = Ph), which contain the relatively rare mu-PH2 and mu-PPhH functionalities. Iron rich Fe2--xMnxP nanoparticles were obtained by thermal decomposition of FeMn(CO)8(mu-PH 2) using solution-based synthetic methods, and empirical evidence suggested that oleic acid was responsible for manganese depletion. Films containing Fe, Mn, and P with the desired stoichiometric ratio of 1:1:1 were prepared using FeMn(CO)8(mu-PH2) in a simple low-pressure metal-organic chemical vapor deposition (MOCVD) apparatus. Although the elemental composition of the precursor was conserved in the deposited film material, spectroscopic evidence indicated that the films were not composed of pure-phase FeMnP, but were actually mixtures of crystalline FeMnP and amorphous FeP and Mn xOy. A new method for the preparation of phase-pure ferromagnetic Fe 3P films on quartz substrates has also been developed. This approach involved the thermal decomposition of the single-source precursors H 2Fe3(CO)9PR (R = tBu or Ph) at 400 °C. The films were deposited using a simple home-built MOCVD apparatus and were characterized using a variety of analytical methods. The films exhibited excellent phase purity, as evidenced by X-ray diffraction, X-ray photoelectron spectroscopy, and field-dependent magnetization measurements, the results of which were all in good agreement with measurements obtained from bulk Fe3P. As-deposited Fe3P films were found to be amorphous, and little or no magnetic hysteresis was observed in plots of magnetization versus applied field. Annealing the Fe3P films at 550 °C resulted in improved crystallinity as well as the observation of magnetic hysteresis.

Phosphide oxides RE2AuP2O (RE = La, Ce, Pr, Nd): synthesis, structure, chemical bonding, magnetism, and 31P and 139La solid state NMR.

PubMed

Bartsch, Timo; Wiegand, Thomas; Ren, Jinjun; Eckert, Hellmut; Johrendt, Dirk; Niehaus, Oliver; Eul, Matthias; Pöttgen, Rainer

2013-02-18

Polycrystalline samples of the phosphide oxides RE(2)AuP(2)O (RE = La, Ce, Pr, Nd) were obtained from mixtures of the rare earth elements, binary rare earth oxides, gold powder, and red phosphorus in sealed silica tubes. Small single crystals were grown in NaCl/KCl fluxes. The samples were studied by powder X-ray diffraction, and the structures were refined from single crystal diffractometer data: La(2)AuP(2)O type, space group C2/m, a = 1515.2(4), b = 424.63(8), c = 999.2(2) pm, β = 130.90(2)°, wR2 = 0.0410, 1050 F(2) values for Ce(2)AuP(2)O, and a = 1503.6(4), b = 422.77(8), c = 993.0(2) pm, β = 130.88(2)°, wR2 = 0.0401, 1037 F(2) values for Pr(2)AuP(2)O, and a = 1501.87(5), b = 420.85(5), c = 990.3(3) pm, β = 131.12(1)°, wR2 = 0.0944, 1143 F(2) values for Nd(2)AuP(2)O with 38 variables per refinement. The structures are composed of [RE(2)O](4+) polycationic chains of cis-edge-sharing ORE(4/2) tetrahedra and polyanionic strands [AuP(2)](4-), which contain gold in almost trigonal-planar phosphorus coordination by P(3-) and P(2)(4-) entities. The isolated phosphorus atoms and the P(2) pairs in La(2)AuP(2)O could clearly be distinguished by (31)P solid state NMR spectroscopy and assigned on the basis of a double quantum NMR technique. Also, the two crystallographically inequivalent La sites could be distinguished by static (139)La NMR in conjunction with theoretical electric field gradient calculations. Temperature-dependent magnetic susceptibility measurements show diamagnetic behavior for La(2)AuP(2)O. Ce(2)AuP(2)O and Pr(2)AuP(2)O are Curie-Weiss paramagnets with experimental magnetic moments of 2.35 and 3.48 μ(B) per rare earth atom, respectively. Their solid state (31)P MAS NMR spectra are strongly influenced by paramagnetic interactions. Ce(2)AuP(2)O orders antiferromagnetically at 13.1(5) K and shows a metamagnetic transition at 11.5 kOe. Pr(2)AuP(2)O orders ferromagnetically at 7.0 K.

An assessment of agricultural pesticide use in Iran, 2012-2014.

PubMed

Morteza, Zaim; Mousavi, Seyed Behzad; Baghestani, Mohammad Ali; Aitio, Antero

2017-01-01

This is the first published assessment on agricultural pesticide use in Iran with the aim to identify pesticide products with a potential of causing acute or chronic hazard to human health. It also establishes a baseline for future comparisons and for trend assessments. The amounts of imported technical materials for formulation by local manufacturers as well as imported final product formulations were extracted from the registration data of the Plant Protection Organization of Iran in 2012-2014. The hazard indicators used were acute oral toxicity and chronic toxicity. For the latter, carcinogenicity, mutagenicity, and adverse effects on reproduction or development (CMR toxicity), and low Acceptable Daily Intake (ADI) were used. The comparative potential of the active ingredients of concern in terms of chronic toxicity was assessed using the average annual volume of their estimated use divided by their respective ADI, called chronic hazard potential (CHP) in the present text. The contribution of individual pesticides in different use categories to the total CHP of the user category, was also calculated, using the average annual volume of the active ingredients of all pesticides used during the period 2012-2014. On average about 14,000 tonnes of agriculture pesticides, expressed in active ingredients (AI), were annually used in Iran. Herbicides constituted the largest volume (43%), followed by insecticides and acaricides (37%) and fungicides (19%). 0.1% and 47% of the formulated products met the criteria of WHO Class Ib (highly hazardous) and Class II (moderately hazardous) products respectively. Aluminium phosphide and magnesium phosphide were identified as products of primary concern and chlorpyrifos, diazinon and paraquat as products of secondary concern, in terms of their acute human health hazard. No compound in carcinogenicity category 1A or 1B or germ cell mutagenicity/reproduction toxicity category 1A was identified. Six compounds (diazinon, chlorpyrifos, dichlorvos, metam sodium, paraquat and dimethoate) were identified as products with chronic hazard potential based on a low ADI. The assessment identified and prioritized agriculture pesticide used in Iran in terms of their acute and chronic hazard to human health for re-registration scheme recently established by PPO and for risk mitigation. It also set priority for research into development of alternative products and practices to minimize pesticide risks. Chronic hazard potential - amount of use adjusted with toxicity may serve as a useful point of reference for trend analysis also in the use of less hazardous agricultural pesticide products.

LEW 88180, LEW 87119, and ALH 85119: New EH6, EL7, and EL4 Enstatite Chondrites

NASA Astrophysics Data System (ADS)

Zhang, Y.; Benoit, P. H.; Sears, D. W. G.

1993-07-01

The EH and EL chondrites formed in a uniquely reducing environment, containing low-Fe pyroxene, abundant metal, and a number of unusual sulphides and other minerals [1]. An important aspect of their history is that while the EL chondrites consist predominantly of metamorphosed meteorites, the EH consist primarily of little-metamorphosed meteorites (e.g., [2]), and yet EL chondrites have lower equilibrium temperatures than EH chondrite [3,4]. To help understand this observation and its implication for the history of the classes, we have been searching for new enstatite chondrites, looking especially for meteorites of previously unknown chemical-petrologic class. Using our normal INAA methods [5] and sample splits of 100-200 mg, the bulk composition of nine Antarctic enstatite chondrites and one fall were determined. The data were used to assign the meteorites to chemical classes, the Ni/Ir vs. Al/V plot (Fig. 1) being especially useful since it uses the refractory element difference between EH and EL chondrites and is insensitive to metal-silicate heterogeneity. The well-analyzed Qingzhen was included to check our method. ALH84170, ALH84206, and EET87746, which Mason described as E3, E4, and E4 were all found to be EH chondrites [6]. Our data for the three paired EL3 chondrites were discussed earlier (MAC88136, 88180, and 88184) [7,8]. LEW88180, LEW87119, and ALH85119, which Mason described as type E6, E6, and E4 respectively [6], are EH, EL, and EL; thus LEW88180 and ALH85119 appear to be the first EH6 and EL4 chondrites. The compositions of kamacite, phosphide, and niningerite-alabandite (Fig. 2) for ALH84170, ALH84206, EET87746, LEW88180, and ALH85119 are consistent with Mason's petrologic type assignments [6]. The mineral composition of LEW88180 (2.7% Si and 9.4% Ni in the kamacite, 7.8% Ni in the phosphide, and 60% FeS in the niningerite) confirms our classification of this meteorite as EH6. ALH85119 contains kamacite with 0.5% Si and 7% Ni, phosphide with 46% Ni and alabandite with 22% FeS, confirming its classification as the first EL4 chondrite. The LEW87119 meteorite has kamacite with 1.5% Si and 9.1% Ni, troilite with 2.9% Cr and 0.64% Ti, and alabandite with the highest FeS (49%) recorded for EL chondrites. Since the meteorite does not appear to be shocked or impact melted (it has medium-grained texture with the slightest indication of chondrules and normal metal and sulfide distribution) and the phase chemistry clearly indicates a higher equilibration temperature than the EL6 chondrites, for the time being we propose to call LEW87119 an EL7 chondrite. With the discovery in the last decade or so of a number of low-petrologic-type EH chondrites and the present discovery of EH6 and EL7 chondrites, the EH class and the EL class now appear to be comparable in their range of mineral compositions and thereby equilibration temperatures. The highest equilibration temperature for the EL chondrites is now ~700 degrees C, which is close to that of EH6 chondrite (Fig. 2). Equilibration temperatures for the EL6 chondrites are similar to those of EH4 chondrites. It may be that EH and EL classes have more similar thermal histories than previously supposed and that it is purely the textures of the two classes that are widely different and in need of further research. References: [1] Keil K. (1968) JGR, 73, 6945-6976. [2] Sears D. W. G. and Weeks K. S. (1984) Nature, 308, 257-259. [3] Skinner B. J. and Luce F. D. (1971) Amer. Min., 56, 1269-1296. [4] Zhang Y. et al. (1992) Meteoritics, 27, 310-311. [5] Weeks K. S.and Sears D. W. G. (1985) GCA, 49, 1525-1536. [6] Mason in Antarctic Meteorite Newsletter (1986, 1987, 1989, and 1990) 9(3), 10(2), 12(1,3), and 13(2,3). [7] Lin Y. T. et al. (1991) LPSC XXII, 811-812. [8] Chang Y. et al. (1992) LPSC XXIII, 217-218.

The New Microwave Temperature and Humidity Profiler (MTHP) Airborne Instrument

NASA Astrophysics Data System (ADS)

Lim, B.; Bendig, R.; Denning, R.; Pandian, P.; Read, W. G.; Tanner, A.

2016-12-01

The Jet Propulsion Laboratory (JPL) has developed a next generation sensor, the Microwave Temperature and Humidity Profiler (MTHP) for use on airborne platforms. The instrument measures the 60 GHz oxygen band and 183 GHz water vapor band, and scans ahead of the aircraft flight path, allowing for atmospheric retrievals above and below the aircraft, to generate vertical profiles. The millimeter wave microwave receivers utilize low noise amplifiers made on the 35 nm indium phosphide (InP) High Electron Mobility Transistors (HEMTs) process that offer low noise figures ( 4 dB). Continuous calibration is performed with a novel rotating drum, through an aperture matched to the measurement frequencies, with two external targets - one at ambient and another heated to 55oC. The instrument performs a scan of the vertical structure of the atmosphere and calibration targets every 1.5 seconds The instrument has recently flown on the Gulfstream 2 in June 2016 and participated in the NCAR ARISTO C-130 flight test campaign in August 2016. The performance of the instrument during these campaigns, will be presented.

Tungsten Hydride Phosphorus- and Arsenic-Bearing Molecules with Double and Triple W-P and W-As Bonds.

PubMed

Andrews, Lester; Cho, Han-Gook; Fang, Zongtang; Vasiliu, Monica; Dixon, David A

2018-05-07

Laser ablation of tungsten metal provides W atoms which react with phosphine and arsine during condensation in excess argon and neon, leading to major new infrared (IR) absorptions. Annealing, UV irradiation, and deuterium substitution experiments coupled with electronic structure calculations at the density functional theory level led to the assignment of the observed IR absorptions to the E≡WH 3 and HE═WH 2 molecules for E = P and As. The potential energy surfaces for hydrogen transfer from PH 3 to the W were calculated at the coupled-cluster CCSD(T)/complete basis set level. Additional weak bands in the phosphide and arsenide W-H stretching region are assigned to the molecules with loss of H from W, E≡WH 2 . The electronic structure calculations show that the E≡WH 3 molecules have a W-E triple bond, the HE═WH 2 molecules have a W-E double bond, and the H 2 E-WH molecules have a W-E single bond. The formation of multiple E-W bonds leads to increasing stability for the isomers.

Efficient Green Emission from Wurtzite Al xIn1- xP Nanowires.

PubMed

Gagliano, L; Kruijsse, M; Schefold, J D D; Belabbes, A; Verheijen, M A; Meuret, S; Koelling, S; Polman, A; Bechstedt, F; Haverkort, J E M; Bakkers, E P A M

2018-06-13

Direct band gap III-V semiconductors, emitting efficiently in the amber-green region of the visible spectrum, are still missing, causing loss in efficiency in light emitting diodes operating in this region, a phenomenon known as the "green gap". Novel geometries and crystal symmetries however show strong promise in overcoming this limit. Here we develop a novel material system, consisting of wurtzite Al x In 1- x P nanowires, which is predicted to have a direct band gap in the green region. The nanowires are grown with selective area metalorganic vapor phase epitaxy and show wurtzite crystal purity from transmission electron microscopy. We show strong light emission at room temperature between the near-infrared 875 nm (1.42 eV) and the "pure green" 555 nm (2.23 eV). We investigate the band structure of wurtzite Al x In 1- x P using time-resolved and temperature-dependent photoluminescence measurements and compare the experimental results with density functional theory simulations, obtaining excellent agreement. Our work paves the way for high-efficiency green light emitting diodes based on wurtzite III-phosphide nanowires.

Tritium-field betacells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walko, R.J.; Lincoln, R.C.; Baca, W.E.

1991-01-01

Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be to hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. Many using low power flux beta emitters, wide bandgap semiconductorsmore » are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method. 7 refs., 11 figs.« less

Tritium-field betacells

NASA Astrophysics Data System (ADS)

Walko, R. J.; Lincoln, R. C.; Baca, W. E.; Goods, S. H.; Negley, G. H.

Betavoltaic power sources operate by converting the nuclear decay energy of beta-emitting radioisotopes into electricity. Since they are not chemically driven, they could operate at temperatures which would either be too hot or too cold for typical chemical batteries. Further, for long lived isotopes, they offer the possibility of multi-decade active lifetimes. Two approaches are being investigated: direct and indirect conversion. Direct conversion cells consist of semiconductor diodes similar to photovoltaic cells. Beta particle directly bombard these cells, generating electron-hole pairs in the semiconductor which are converted to useful power. When using low power flux beta emitters, wide bandgap semiconductors are required to achieve useful conversion efficiencies. The combination of tritium, as the beta emitter, and gallium phosphide (GaP), as the semiconductor converter, was evaluated. Indirect conversion betacells first convert the beta energy to light with a phosphor, and then to electricity with photovoltaic cells. An indirect conversion power source using a tritium radioluminescent (RL) light is being investigated. Our analysis indicates that this approach has the potential for significant volume and cost savings over the direct conversion method.

Experimental analysis and modeling of melt growth processes

NASA Astrophysics Data System (ADS)

Müller, Georg

2002-04-01

Melt growth processes provide the basic crystalline materials for many applications. The research and development of crystal growth processes is therefore driven by the demands which arise from these specific applications; however, common goals include an increased uniformity of the relevant crystal properties at the micro- and macro-scale, a decrease of deleterious crystal defects, and an increase of crystal dimensions. As melt growth equipment and experimentation becomes more and more expensive, little room remains for improvements by trial and error procedures. A more successful strategy is to optimize the crystal growth process by a combined use of experimental process analysis and computer modeling. This will be demonstrated in this paper by several examples from the bulk growth of silicon, gallium arsenide, indium phosphide, and calcium fluoride. These examples also involve the most important melt growth techniques, crystal pulling (Czochralski methods) and vertical gradient freeze (Bridgman-type methods). The power and success of the above optimization strategy, however, is not limited only to the given examples but can be generalized and applied to many types of bulk crystal growth.

Surface plasmon polariton nanocavity with ultrasmall mode volume

NASA Astrophysics Data System (ADS)

Yue, Wencheng; Yao, Peijun; Luo, Huiwen; Liu, Wen

2017-08-01

We present a plasmonic nanocavity structure, consisting of a gallium phosphide (GaP) cylinder penetrating into a rectangular silver plate, and study its properties using a finite element method (FEM). An ultrasmall mode volume of 1.5×10-5[λ_0/(2n)]3 is achieved, which is more than 200 times smaller than the previous ultrasmall mode volume plasmonic nanodisk resonators. Meanwhile, the quality factor of the plasmonic nanocavity is about 38.2 and is over two times greater than the ultrasmall mode volume plasmonic nanodisk resonators. Compared to the aforementioned plasmonic nanodisk resonators, a more than one-order of magnitude larger Purcell factor of 1.2×104 is achieved. We determined the resonant modes of our plasmonic nanocavity are dipolar plasmon modes by analyzing the electric field properties. In addition, we investigate the dependence of the optical properties on the refractive index of the cavity material and discuss the effect of including the silica (SiO2) substrate. Our work provides an alternative approach to achieve ultrasmall plasmonic nanocavity of interest in applications to many areas of research, including device physics, nonlinear optics and quantum optics.

Electron beam induced damage in PECVD Si3N4 and SiO2 films on InP

NASA Technical Reports Server (NTRS)

Pantic, Dragan M.; Kapoor, Vik J.; Young, Paul G.; Williams, Wallace D.; Dickman, John E.

1990-01-01

Phosphorus rich plasma enhanced chemical vapor deposition (PECVD) of silicon nitride and silicon dioxide films on n-type indium phosphide (InP) substrates were exposed to electron beam irradiation in the 5 to 40 keV range for the purpose of characterizing the damage induced in the dielectic. The electron beam exposure was on the range of 10(exp -7) to 10(exp -3) C/sq cm. The damage to the devices was characterized by capacitance-voltage (C-V) measurements of the metal insulator semiconductor (MIS) capacitors. These results were compared to results obtained for radiation damage of thermal silicon dioxide on silicon (Si) MOS capacitors with similar exposures. The radiation induced damage in the PECVD silicon nitride films on InP was successfully annealed out in an hydrogen/nitrogen (H2/N2) ambient at 400 C for 15 min. The PECVD silicon dioxide films on InP had the least radiation damage, while the thermal silicon dioxide films on Si had the most radiation damage.

London penetration depth and superfluid density of single-crystalline Fe1+y(Te1-xSex) and Fe1+y(Te1-xSx)

NASA Astrophysics Data System (ADS)

Kim, H.; Martin, C.; Gordon, R. T.; Tanatar, M. A.; Hu, J.; Qian, B.; Mao, Z. Q.; Hu, Rongwei; Petrovic, C.; Salovich, N.; Giannetta, R.; Prozorov, R.

2010-05-01

The in-plane London penetration depth, λ(T) , was measured in single crystals of the iron-chalcogenide superconductors Fe1.03(Te0.63Se0.37) and Fe1.06(Te0.88S0.14) by using a radio-frequency tunnel diode resonator. Similar to the iron-arsenides and in stark contrast to the iron-phosphides, iron-chalcogenides exhibit a nearly quadratic temperature variation of λ(T) at low temperatures. The absolute value of the penetration depth in the T→0 limit was determined for Fe1.03(Te0.63Se0.37) by using an Al coating technique, giving λ(0)≈560±20nm . The superfluid density ρs(T)=λ2(0)/λ2(T) was fitted with a self-consistent two-gap γ model. While two different gaps are needed to describe the full-range temperature variation in ρs(T) , a nonexponential low-temperature behavior requires pair-breaking scattering, and therefore an unconventional (e.g., s± or nodal) order parameter.

Annular solid-immersion lenslet array super-resolution optical microscopy

NASA Astrophysics Data System (ADS)

Liau, Z. L.

2012-10-01

We describe a novel solid-immersion lenslet array, micro-fabricated in a chip form in the high-index (3.45) gallium phosphide. The innovatively designed lenslet features an annular aperture with appropriately patterned light absorbers and antireflection coatings. The array chip is easy to handle and enables the direct deposition of the specimen of interest onto its back-plane for tight adhesion and good optical coupling. The ensuing diffraction from the near field can yield supercritical rays inside the high-index lenslet and can, therefore, overcome the refraction and critical-angle limitations. This model showed agreement with the experimental observation of the solid-immersion fluorescence microscopy imaging, in which the refracted rays were completely blocked by the annular aperture. A large longitudinal (depth) magnification effect was also predicted and showed agreement with experiment. The annular lenslet's additional advantages of improved resolution and contrast were also discussed. Resolution of nested-L patterns with grating pitch as small as 100 nm was experimentally demonstrated. The demonstrated annular solid-immersion lenslet array concept is promising for a wider use in super-resolution optical microscopy.

Magnetic phase transitions and magnetization reversal in MnRuP

NASA Astrophysics Data System (ADS)

Lampen-Kelley, P.; Mandrus, D.

The ternary phosphide MnRuP is an incommensurate antiferromagnetic metal crystallizing in the non-centrosymmetric Fe2P-type crystal structure. Below the Neel transition at 250 K, MnRuP exhibits hysteretic anomalies in resistivity and magnetic susceptibility curves as the propagation vectors of the spiral spin structure change discontinuously across T1 = 180 K and T2 = 100 K. Temperature-dependent X-ray diffraction data indicate that the first-order spin reorientation occurs in the absence of a structural transition. A strong magnetization reversal (MR) effect is observed upon cooling the system through TN in moderate dc magnetic fields. Positive magnetization is recovered on further cooling through T1 and maintained in subsequent warming curves. The field dependence and training of the MR effect in MnRuP will be discussed in terms of the underlying magnetic structures and compared to anomalous MR observed in vanadate systems. This work is supported by the Gordon and Betty Moore Foundation GBMF4416 and U.S. DOE, Office of Science, BES, Materials Science and Engineering Division.

Supported black phosphorus nanosheets as hydrogen-evolving photocatalyst achieving 5.4% energy conversion efficiency at 353 K.

PubMed

Tian, Bin; Tian, Bining; Smith, Bethany; Scott, M C; Hua, Ruinian; Lei, Qin; Tian, Yue

2018-04-11

Solar-driven water splitting using powdered catalysts is considered as the most economical means for hydrogen generation. However, four-electron-driven oxidation half-reaction showing slow kinetics, accompanying with insufficient light absorption and rapid carrier combination in photocatalysts leads to low solar-to-hydrogen energy conversion efficiency. Here, we report amorphous cobalt phosphide (Co-P)-supported black phosphorus nanosheets employed as photocatalysts can simultaneously address these issues. The nanosheets exhibit robust hydrogen evolution from pure water (pH = 6.8) without bias and hole scavengers, achieving an apparent quantum efficiency of 42.55% at 430 nm and energy conversion efficiency of over 5.4% at 353 K. This photocatalytic activity is attributed to extremely efficient utilization of solar energy (~75% of solar energy) by black phosphorus nanosheets and high-carrier separation efficiency by amorphous Co-P. The hybrid material design realizes efficient solar-to-chemical energy conversion in suspension, demonstrating the potential of black phosphorus-based materials as catalysts for solar hydrogen production.

Anionic Redox Chemistry in Polysulfide Electrode Materials for Rechargeable Batteries.

PubMed

Grayfer, Ekaterina D; Pazhetnov, Egor M; Kozlova, Mariia N; Artemkina, Sofya B; Fedorov, Vladimir E

2017-12-22

Classical Li-ion battery technology is based on the insertion of lithium ions into cathode materials involving metal (cationic) redox reactions. However, this vision is now being reconsidered, as many new-generation electrode materials with enhanced reversible capacities operate through combined cationic and anionic (non-metal) reversible redox processes or even exclusively through anionic redox transformations. Anionic participation in the redox reactions is observed in materials with more pronounced covalency, which is less typical for oxides, but quite common for phosphides or chalcogenides. In this Concept, we would like to draw the reader's attention to this new idea, especially, as it applies to transition-metal polychalcogenides, such as FeS 2 , VS 4 , TiS 3 , NbS 3 , TiS 4 , MoS 3 , etc., in which the key role is played by the (S-S) 2- /2 S 2- redox reaction. The exploration and better understanding of the anion-driven chemistry is important for designing advanced materials for battery and other energy-related applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multidimensional Germanium-Based Materials as Anodes for Lithium-Ion Batteries.

PubMed

Qin, Jinwen; Cao, Minhua

2016-04-20

Metallic germanium is an ideal anode for lithium-ion batteries (LIBs), owing to its high theoretical capacity (1624 mA h g(-1) ) and low operating voltage. Herein, we highlight recent advances in the development of Ge-based anodes in LIBs, although improvements in their coulombic efficiency (CE), capacity retention, and rate performance are still required. One of the major concerns facing the development of Ge anodes is the controlled formation of microstructures. In this Focus Review, we summarize Ge-based materials with different structural dimensions, that is, zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), three-dimensional (3D), and even monolithic and macroscale structures. Moreover, the design of Ge-based oxide materials, as an effective route for achieving higher Li-storage capacities and cycling performance, is also discussed. Finally, we briefly summarize new types of Ge-based materials, such as ternary germanium oxides, germanium sulfides, and germanium phosphides, and predict that they will bring about a reformation in the field of LIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Promoting Charge Separation and Injection by Optimizing the Interfaces of GaN:ZnO Photoanode for Efficient Solar Water Oxidation.

PubMed

Wang, Zhiliang; Zong, Xu; Gao, Yuying; Han, Jingfeng; Xu, Zhiqiang; Li, Zheng; Ding, Chunmei; Wang, Shengyang; Li, Can

2017-09-13

Photoelectrochemical water splitting provides an attractive way to store solar energy in molecular hydrogen as a kind of sustainable fuel. To achieve high solar conversion efficiency, the most stringent criteria are effective charge separation and injection in electrodes. Herein, efficient photoelectrochemical water oxidation is realized by optimizing charge separation and surface charge transfer of GaN:ZnO photoanode. The charge separation can be greatly improved through modified moisture-assisted nitridation and HCl acid treatment, by which the interfaces in GaN:ZnO solid solution particles are optimized and recombination centers existing at the interfaces are depressed in GaN:ZnO photoanode. Moreover, a multimetal phosphide of NiCoFeP was employed as water oxidation cocatalyst to improve the charge injection at the photoanode/electrolyte interface. Consequently, it significantly decreases the overpotential and brings the photocurrent to a benchmark of 3.9 mA cm -2 at 1.23 V vs RHE and a solar conversion efficiency over 1% was obtained.

Imaging Pancreatic Cancer Using Bioconjugated InP Quantum Dots

PubMed Central

Yong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J.; Maitra, Anirban; Prasad, Paras N.

2009-01-01

In this paper, we report the successful use of non-cadmium based quantum dots (QDs) as highly efficient and non-toxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulphide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepared by a hot colloidal synthesis method in non-aqueous media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aqueous media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anti-claudin 4 and anti-prostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in non-pancreatic cancer based cell lines which are negative for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer. PMID:19243145

Imaging pancreatic cancer using bioconjugated InP quantum dots.

PubMed

Yong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J; Maitra, Anirban; Prasad, Paras N

2009-03-24

In this paper, we report the successful use of non-cadmium-based quantum dots (QDs) as highly efficient and nontoxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulfide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepared by a hot colloidal synthesis method in nonaqueous media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aqueous media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anticlaudin 4 and antiprostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor-mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in nonpancreatic cancer based cell lines which are negative for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium-based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer.

Sintered Cr/Pt and Ni/Au ohmic contacts to B 12P 2

DOE PAGES

Frye, Clint D.; Kucheyev, Sergei O.; Edgar, James H.; ...

2015-04-09

With this study, icosahedral boron phosphide (B 12P 2) is a wide-bandgap semiconductor possessing interesting properties such as high hardness, chemical inertness, and the reported ability to self-heal from irradiation by high energy electrons. Here, the authors developed Cr/Pt and Ni/Au ohmic contacts to epitaxially grown B 12P 2 for materials characterization and electronic device development. Cr/Pt contacts became ohmic after annealing at 700 °C for 30 s with a specific contact resistance of 2×10 –4 Ω cm 2, as measured by the linear transfer length method. Ni/Au contacts were ohmic prior to any annealing, and their minimum specific contactmore » resistance was ~l–4 × 10 –4 Ω cm 2 after annealing over the temperature range of 500–800 °C. Rutherford backscattering spectrometry revealed a strong reaction and intermixing between Cr/Pt and B 12P 2 at 700 °C and a reaction layer between Ni and B 12P 2 thinner than ~25 nm at 500 °C.« less

Extraterrestrial flux of potentially prebiotic C, N, and P to the early Earth.

PubMed

Pasek, Matthew; Lauretta, Dante

2008-02-01

With growing evidence for a heavy bombardment period ending 4-3.8 billion years ago, meteorites and comets may have been an important source of prebiotic carbon, nitrogen, and phosphorus on the early Earth. Life may have originated shortly after the late-heavy bombardment, when concentrations of organic compounds and reactive phosphorus were enough to "kick life into gear". This work quantifies the sources of potentially prebiotic, extraterrestrial C, N, and P and correlates these fluxes with a comparison to total Ir fluxes, and estimates the effect of atmosphere on the survival of material. We find (1) that carbonaceous chondrites were not a good source of organic compounds, but interplanetary dust particles provided a constant, steady flux of organic compounds to the surface of the Earth, (2) extraterrestrial metallic material was much more abundant on the early Earth, and delivered reactive P in the form of phosphide minerals to the Earth's surface, and (3) large impacts provided substantial local enrichments of potentially prebiotic reagents. These results help elucidate the potential role of extraterrestrial matter in the origin of life.

Epitaxy of boron phosphide on AlN, 4H-SiC, 3C-SiC and ZrB2 substrates

NASA Astrophysics Data System (ADS)

Padavala, Balabalaji

The semiconductor boron phosphide (BP) has many outstanding features making it attractive for developing various electronic devices, including neutron detectors. In order to improve the efficiency of these devices, BP must have high crystal quality along with the best possible electrical properties. This research is focused on growing high quality crystalline BP films on a variety of superior substrates like AlN, 4H-SiC, 3C-SiC and ZrB2 by chemical vapor deposition. In particular, the influence of various parameters such as temperature, reactant flow rates, and substrate type and its crystalline orientation on the properties of BP films were studied in detail. Twin-free BP films were produced by depositing on off-axis 4H-SiC(0001) substrate tilted 4° toward [11¯00] and crystal symmetry matched zincblende 3C-SiC. BP crystalline quality improved at higher deposition temperature (1200°C) when deposited on AlN, 4H-SiC, whereas increased strain in 3C-SiC and increased boron segregation in ZrB2 at higher temperatures limited the best deposition temperature to below 1200°C. In addition, higher flow ratios of PH 3 to B2H6 resulted in smoother films and improved quality of BP on all substrates. The FWHM of the Raman peak (6.1 cm -1), XRD BP(111) peak FWHM (0.18°) and peak ratios of BP(111)/(200) = 5157 and BP(111)/(220) = 7226 measured on AlN/sapphire were the best values reported in the literature for BP epitaxial films. The undoped films on AlN/sapphire were n-type with a highest electron mobility of 37.8 cm2/V˙s and a lowest carrier concentration of 3.15x1018 cm -3. Raman imaging had lower values of FWHM (4.8 cm-1 ) and a standard deviation (0.56 cm-1) for BP films on AlN/sapphire compared to 4H-SiC, 3C-SiC substrates. X-ray diffraction and Raman spectroscopy revealed residual tensile strain in BP on 4H-SiC, 3C-SiC, ZrB2/4H-SiC, bulk AlN substrates while compressive strain was evident on AlN/sapphire and bulk ZrB2 substrates. Among the substrates studied, AlN/sapphire proved to be the best choice for BP epitaxy, even though it did not eliminate rotational twinning in BP. The substrates investigated in this work were found to be viable for BP epitaxy and show promising potential for further enhancement of BP properties.

The core contribution of transmission electron microscopy to functional nanomaterials engineering

NASA Astrophysics Data System (ADS)

Carenco, Sophie; Moldovan, Simona; Roiban, Lucian; Florea, Ileana; Portehault, David; Vallé, Karine; Belleville, Philippe; Boissière, Cédric; Rozes, Laurence; Mézailles, Nicolas; Drillon, Marc; Sanchez, Clément; Ersen, Ovidiu

2016-01-01

Research on nanomaterials and nanostructured materials is burgeoning because their numerous and versatile applications contribute to solve societal needs in the domain of medicine, energy, environment and STICs. Optimizing their properties requires in-depth analysis of their structural, morphological and chemical features at the nanoscale. In a transmission electron microscope (TEM), combining tomography with electron energy loss spectroscopy and high-magnification imaging in high-angle annular dark-field mode provides access to all features of the same object. Today, TEM experiments in three dimensions are paramount to solve tough structural problems associated with nanoscale matter. This approach allowed a thorough morphological description of silica fibers. Moreover, quantitative analysis of the mesoporous network of binary metal oxide prepared by template-assisted spray-drying was performed, and the homogeneity of amino functionalized metal-organic frameworks was assessed. Besides, the morphology and internal structure of metal phosphide nanoparticles was deciphered, providing a milestone for understanding phase segregation at the nanoscale. By extrapolating to larger classes of materials, from soft matter to hard metals and/or ceramics, this approach allows probing small volumes and uncovering materials characteristics and properties at two or three dimensions. Altogether, this feature article aims at providing (nano)materials scientists with a representative set of examples that illustrates the capabilities of modern TEM and tomography, which can be transposed to their own research.Research on nanomaterials and nanostructured materials is burgeoning because their numerous and versatile applications contribute to solve societal needs in the domain of medicine, energy, environment and STICs. Optimizing their properties requires in-depth analysis of their structural, morphological and chemical features at the nanoscale. In a transmission electron microscope (TEM), combining tomography with electron energy loss spectroscopy and high-magnification imaging in high-angle annular dark-field mode provides access to all features of the same object. Today, TEM experiments in three dimensions are paramount to solve tough structural problems associated with nanoscale matter. This approach allowed a thorough morphological description of silica fibers. Moreover, quantitative analysis of the mesoporous network of binary metal oxide prepared by template-assisted spray-drying was performed, and the homogeneity of amino functionalized metal-organic frameworks was assessed. Besides, the morphology and internal structure of metal phosphide nanoparticles was deciphered, providing a milestone for understanding phase segregation at the nanoscale. By extrapolating to larger classes of materials, from soft matter to hard metals and/or ceramics, this approach allows probing small volumes and uncovering materials characteristics and properties at two or three dimensions. Altogether, this feature article aims at providing (nano)materials scientists with a representative set of examples that illustrates the capabilities of modern TEM and tomography, which can be transposed to their own research. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05460e

High Efficiency Multijunction Solar Cells with Finely-Tuned Quantum Wells

NASA Astrophysics Data System (ADS)

Varonides, Argyrios C.

The field of high efficiency (inorganic) photovoltaics (PV) is rapidly maturing in both efficiency goals and cover all cost reduction of fabrication. On one hand, know-how from space industry in new solar cell design configurations and on the other, fabrication cost reduction challenges for terrestrial uses of solar energy, have paved the way to a new generation of PV devices, capable of capturing most of the solar spectrum. For quite a while now, the goal of inorganic solar cell design has been the total (if possible) capture-absorption of the solar spectrum from a single solar cell, designed in such a way that a multiple of incident wavelengths could be simultaneously absorbed. Multi-absorption in device physics indicates parallel existence of different materials that absorb solar photons of different energies. Bulk solid state devices absorb at specific energy thresholds, depending on their respective energy gap (EG). More than one energy gaps would on principle offer new ways of photon absorption: if such a structure could be fabricated, two or more groups of photons could be absorbed simultaneously. The point became then what lattice-matched semiconductor materials could offer such multiple levels of absorption without much recombination losses. It was soon realized that such layer multiplicity combined with quantum size effects could lead to higher efficiency collection of photo-excited carriers. At the moment, the main reason that slows down quantum effect solar cell production is high fabrication cost, since it involves primarily expensive methods of multilayer growth. Existing multi-layer cells are fabricated in the bulk, with three (mostly) layers of lattice-matched and non-lattice-matched (pseudo-morphic) semiconductor materials (GaInP/InGaN etc), where photo-carrier collection occurs in the bulk of the base (coming from the emitter which lies right under the window layer). These carriers are given excess to conduction via tunnel junction (grown between at each interface and connecting the layers in series). This basic idea of a design has proven very successful in recent years, leading to solar cells of efficiency levels well above 30% (Fraunhofer Institute's multi-gap solar cell at 40.8%, and NREL's device at 40.2% respectively). Successful alloys have demonstrated high performance, such as InxGa1 - xP alloys (x (%) of gallium phosphide and (1 - x) (%) of indium phosphide). Other successful candidates, in current use and perpetual cell design consideration, are the lattice-matched GaAs/AlGaAs and InP/GaAs pairs or AlAs/GaAs/GaAs triple layers and alloys, which are heavily used in both solar and the electronics industry.

Shape-Controlled Synthesis of Co2P Nanostructures and Their Application in Supercapacitors.

PubMed

Chen, Xiaojuan; Cheng, Ming; Chen, Di; Wang, Rongming

2016-02-17

Co2P nanostructures with rod-like and flower-like morphologies have been synthesized by controlling the decomposition process of Co(acac)3 in oleylamine system with triphenylphosphine as phosphorus source. Investigations indicate that the final morphologies of the products are determined by their peculiar phosphating processes. Electrochemical measurements manifest that the Co2P nanostructures exhibit excellent morphology-dependent supercapacitor properties. Compared with that of 284 F g(-1) at a current density of 1 A g(-1) for Co2P nanorods, the capacitance for Co2P nanoflowers reaches 416 F g(-1) at the same current density. Furthermore, an optimized asymmetric supercapacitor by using Co2P nanoflowers as anode and graphene as cathode is fabricated. It can deliver a high energy density of 8.8 Wh kg(-1) (at a high power density of 6 kW kg(-1)) and good cycling stability with over 97% specific capacitance remained after 6000 cycles, which makes the Co2P nanostructures potential applications in energy storage/conversion systems. This study paves the way to explore a new class of cobalt phosphide-based materials for supercapacitor applications.

Synergy in Lignin Upgrading by a Combination of Cu-Based Mixed Oxide and Ni-Phosphide Catalysts in Supercritical Ethanol

PubMed Central

2017-01-01

The depolymerization of lignin to bioaromatics usually requires a hydrodeoxygenation (HDO) step to lower the oxygen content. A mixed Cu–Mg–Al oxide (CuMgAlOx) is an effective catalyst for the depolymerization of lignin in supercritical ethanol. We explored the use of Ni-based cocatalysts, i.e. Ni/SiO2, Ni2P/SiO2, and Ni/ASA (ASA = amorphous silica alumina), with the aim of combining lignin depolymerization and HDO in a single reaction step. While the silica-supported catalysts were themselves hardly active in lignin upgrading, Ni/ASA displayed comparable lignin monomer yield as CuMgAlOx. A drawback of using an acidic support is extensive dehydration of the ethanol solvent. Instead, combining CuMgAlOx with Ni/SiO2 and especially Ni2P/SiO2 proved to be effective in increasing the lignin monomer yield, while at the same time reducing the oxygen content of the products. With Ni2P/SiO2, the lignin monomer yield was 53 wt %, leading to nearly complete deoxygenation of the aromatic products. PMID:28405528

High-energy, tunable, mid-infrared, picosecond optical parametric generation in CdSiP2

NASA Astrophysics Data System (ADS)

Chaitanya Kumar, S.; Jelínek, M.; Baudisch, M.; Zawilski, K. T.; Schunemann, P. G.; Kubecek, V.; Biegert, J.; Ebrahim-Zadeh, M.

2012-06-01

We report a tunable, high-energy, single-pass, optical parametric generator (OPG) based on the new nonlinear material, cadmium silicon phosphide, CdSiP2. The OPG is pumped by a laboratory designed cavity-dumped passively mode-locked, diode-pumped, Nd:YAG oscillator, providing 25 μJ pulses in 20 ps at 5 Hz. The pump energy is further boosted by a flashlamp-pumped Nd:YAG amplifier to 2.5 mJ. The OPG is temperature tunable over 1263-1286 nm (23 nm) in the signal and 6153-6731 nm (578 nm) in the idler, corresponding to a total tuning range of 601 nm. Using the single-pass OPG configuration, we have generated signal energy as high as 636 μJ at 1283 nm, together with an idler energy of 33 μJ at 6234 nm, for 2.1 mJ of input pump energy. The signal pulses generated from the OPG have a Gaussian pulse duration of 24 ps and an FWHM spectral bandwidth of 10.4 nm at central wavelength of 1276 nm. The corresponding idler spectrum has an FWHM bandwidth of 140 nm centered at 6404 nm.

Metal-Organic Framework-Derived Materials for Sodium Energy Storage.

PubMed

Zou, Guoqiang; Hou, Hongshuai; Ge, Peng; Huang, Zhaodong; Zhao, Ganggang; Yin, Dulin; Ji, Xiaobo

2018-01-01

Recently, sodium-ion batteries (SIBs) are extensively explored and are regarded as one of the most promising alternatives to lithium-ion batteries for electrochemical energy conversion and storage, owing to the abundant raw material resources, low cost, and similar electrochemical behavior of elemental sodium compared to lithium. Metal-organic frameworks (MOFs) have attracted enormous attention due to their high surface areas, tunable structures, and diverse applications in drug delivery, gas storage, and catalysis. Recently, there has been an escalating interest in exploiting MOF-derived materials as anodes for sodium energy storage due to their fast mass transport resulting from their highly porous structures and relatively simple preparation methods originating from in situ thermal treatment processes. In this Review, the recent progress of the sodium-ion storage performances of MOF-derived materials, including MOF-derived porous carbons, metal oxides, metal oxide/carbon nanocomposites, and other materials (e.g., metal phosphides, metal sulfides, and metal selenides), as SIB anodes is systematically and completely presented and discussed. Moreover, the current challenges and perspectives of MOF-derived materials in electrochemical energy storage are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced broadband absorption in nanowire arrays with integrated Bragg reflectors

NASA Astrophysics Data System (ADS)

Aghaeipour, Mahtab; Pettersson, Håkan

2018-05-01

A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire (NW) arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) NWs, respectively. We theoretically show that by enclosing only two periods of In0.56Ga0.44As/InP DBRs, an unselective 78% absorption efficiency (72% for NWs without DBRs) is obtained at normal incidence in the spectral range from 300 nm to 920 nm. Under oblique light incidence, the absorption efficiency is enhanced up to about 85% at an incidence angle of 50°. By increasing the number of DBR periods from two to five, the absorption efficiency is further enhanced up to 95% at normal incidence. In this work, we calculated optical spectra for InP NWs, but the results are expected to be valid for other direct band gap III-V semiconductor materials. We believe that our proposed idea of integrating DBRs in NWs offers great potential for high-performance photovoltaic applications.

Elucidating the electron transport in semiconductors via Monte Carlo simulations: an inquiry-driven learning path for engineering undergraduates

NASA Astrophysics Data System (ADS)

Persano Adorno, Dominique; Pizzolato, Nicola; Fazio, Claudio

2015-09-01

Within the context of higher education for science or engineering undergraduates, we present an inquiry-driven learning path aimed at developing a more meaningful conceptual understanding of the electron dynamics in semiconductors in the presence of applied electric fields. The electron transport in a nondegenerate n-type indium phosphide bulk semiconductor is modelled using a multivalley Monte Carlo approach. The main characteristics of the electron dynamics are explored under different values of the driving electric field, lattice temperature and impurity density. Simulation results are presented by following a question-driven path of exploration, starting from the validation of the model and moving up to reasoned inquiries about the observed characteristics of electron dynamics. Our inquiry-driven learning path, based on numerical simulations, represents a viable example of how to integrate a traditional lecture-based teaching approach with effective learning strategies, providing science or engineering undergraduates with practical opportunities to enhance their comprehension of the physics governing the electron dynamics in semiconductors. Finally, we present a general discussion about the advantages and disadvantages of using an inquiry-based teaching approach within a learning environment based on semiconductor simulations.

InP Nanoflag Growth from a Nanowire Template by in Situ Catalyst Manipulation.

PubMed

Kelrich, Alexander; Sorias, Ofir; Calahorra, Yonatan; Kauffmann, Yaron; Gladstone, Ran; Cohen, Shimon; Orenstein, Meir; Ritter, Dan

2016-04-13

Quasi-two-dimensional semiconductor materials are desirable for electronic, photonic, and energy conversion applications as well as fundamental science. We report on the synthesis of indium phosphide flag-like nanostructures by epitaxial growth on a nanowire template at 95% yield. The technique is based on in situ catalyst unpinning from the top of the nanowire and its induced migration along the nanowire sidewall. Investigation of the mechanism responsible for catalyst movement shows that its final position is determined by the structural defect density along the nanowire. The crystal structure of the "flagpole" nanowire is epitaxially transferred to the nanoflag. Pure wurtzite InP nanomembranes with just a single stacking fault originating from the defect in the flagpole that pinned the catalyst were obtained. Optical characterization shows efficient highly polarized photoluminescence at room temperature from a single nanoflag with up to 90% degree of linear polarization. Electric field intensity enhancement of the incident light was calculated to be 57, concentrated at the nanoflag tip. The presented growth method is general and thus can be employed for achieving similar nanostructures in other III-V semiconductor material systems with potential applications in active nanophotonics.

Synergy in Lignin Upgrading by a Combination of Cu-Based Mixed Oxide and Ni-Phosphide Catalysts in Supercritical Ethanol.

PubMed

Korányi, Tamás I; Huang, Xiaoming; Coumans, Alessandro E; Hensen, Emiel J M

2017-04-03

The depolymerization of lignin to bioaromatics usually requires a hydrodeoxygenation (HDO) step to lower the oxygen content. A mixed Cu-Mg-Al oxide (CuMgAlO x ) is an effective catalyst for the depolymerization of lignin in supercritical ethanol. We explored the use of Ni-based cocatalysts, i.e. Ni/SiO 2 , Ni 2 P/SiO 2 , and Ni/ASA (ASA = amorphous silica alumina), with the aim of combining lignin depolymerization and HDO in a single reaction step. While the silica-supported catalysts were themselves hardly active in lignin upgrading, Ni/ASA displayed comparable lignin monomer yield as CuMgAlO x . A drawback of using an acidic support is extensive dehydration of the ethanol solvent. Instead, combining CuMgAlO x with Ni/SiO 2 and especially Ni 2 P/SiO 2 proved to be effective in increasing the lignin monomer yield, while at the same time reducing the oxygen content of the products. With Ni 2 P/SiO 2 , the lignin monomer yield was 53 wt %, leading to nearly complete deoxygenation of the aromatic products.

A Narrative Review of Acute Adult Poisoning in Iran

PubMed Central

Alinejad, Samira; Zamani, Nasim; Abdollahi, Mohammad; Mehrpour, Omid

2017-01-01

Poisoning is a frequent cause of referral to medical emergencies and a major health problem around the world, especially in developing countries. We aimed to review the epidemiology and pattern of adult poisoning in Iran in order to facilitate the early diagnosis and management of poisoning. The pattern of poisoning is different in various parts of Iran. Pharmaceutical compounds were the most common cause of poisoning in most parts of Iran. Pesticide-related toxicities were more common in northern agricultural regions, whereas bites and stings were seen more commonly in southern Iran. Carbon monoxide poisoning was common in cities with many motor vehicles such as Tehran and in colder climates such as in northern and western regions due to inadequately vented gas appliances such as stoves and heaters. Majoon Birjandi (containing cannabis) is a unique substance used in eastern Iran. Poisoning by opioids, tramadol, and pesticides (organophosphate and aluminum phosphide) has remained a common hazard in Iran. Poisoning-associated morbidity and mortality rates vary by region and have changed over time due to the introduction of new drugs and chemicals. Early diagnosis and proper treatment may be lifesaving; thus, understanding the general pattern of poisoning in different regions is important. PMID:28761199

A novel optical fibre doped with the nano-material as InP

NASA Astrophysics Data System (ADS)

Chen, Xi; Lee, Ly Guat; Zhang, Ru

2007-11-01

As the key of these optical devices which are widely used in the communication system, high nonlinear optical fibre will play an important role in the future optical fibre communication. With recent growth of nano-technology, researchers are hoping to obtain some kinds of optical fibre by combining the optical fibre with the nanotechnology. According to this current situation, the optical fibre doped with nano-material as InP (indium phosphide) is manufactured by using the MCVD (modified chemical vapor deposition) technology after our comprehensive consideration of many relative factors. Proved by experiments, this novel optical fibre has an excellent waveguide characteristic. After a consideration of the model of this novel optical fibre, its propagation constant β has been simulated by using the FEM (finite element method), and the graphs of presentation of magnetic field of the core are also obtained. In accordance with the results, the effective refractive index n eff = 1.401 has be calculated. Both the calculated result and the simulated graphs are matching well with the test, and this result is a step-stone bridge for future research of nonlinear parameter on this novel optical fiber.

FeSi4P4: A novel negative electrode with atypical electrochemical mechanism for Li and Na-ion batteries

NASA Astrophysics Data System (ADS)

Coquil, Gaël; Fullenwarth, Julien; Grinbom, Gal; Sougrati, Moulay Tahar; Stievano, Lorenzo; Zitoun, David; Monconduit, Laure

2017-12-01

The electrochemical mechanism and performance of FeSi4P4, vs. Na and Li were studied using a combination of operando X-ray diffraction, 57Fe Mössbauer spectroscopy, and SQUID magnetometry. This silicon- and phosphorous-rich material exhibits a high capacity of 1750 mAh/g, retaining 1120 mAh/g after 40 cycles, and reacts through an original reversible mechanism surprisingly involving only slight changes in the chemical environment of the iron. Magnetic measurements and 57Fe Mössbauer spectroscopy at low temperature reveal the reversible but incomplete change of the magnetic moment upon charge and discharge. Such a mild reversible process without drastic phase transition (with the exception of the crystalline to amorphous transition during the first lithiation) can explain the satisfying capacity retention. The electrochemical mechanism appears thus to be significantly different from the classical conversion or alloying/dealloying mechanisms usually observed in Lithium ion batteries for p-group element based materials. The same iron silicon phosphide electrode shows also interesting but significantly lower performance vs. Na, with a limited capacity retention 350 mAh/g.

Tapping the potential of trioctylphosphine (TOP) in the realization of highly luminescent blue-emitting colloidal indium phosphide (InP) quantum dots

NASA Astrophysics Data System (ADS)

Singh, Akanksha; Chawla, Parul; Jain, Shefali; Sharma, Shailesh Narain

2017-06-01

In this work, extremely small blue emitting colloidal InP-based quantum dots (size 2-5 nm) have been synthesized using trioctylphosphine (TOP) as a source of phosphorus. The method reported here is unconventional, quite rapid ( 90 min), more viable, less expensive and relatively greener as compared to other conventional methods that employ tristrimethylsilyylphosphine(P(SiMe3)3) which is scarce, expensive, flammable, highly toxic and even banned in a few countries. Highly luminescent InP QDs having bluish-green emission (λ 490 nm) can be synthesized using this method without resorting to any post-synthesis etching to tune the emission to the blue region. Besides being the source of phosphorus and the particle size regulating agent, the efficacy of TOP is further realized during synthesis via its reduction of indium salt, which aids in the formation of indium metal and then subsequently in the development of InP QDs. The PL intensity of as-synthesized InP QDs is further enhanced by growing a shell of wide band gap material, i.e. ZnS resulting in a concurrent increment in quantum yield from 25% to 38% respectively.

In-situ conversion of rGO/Ni2P composite from GO/Ni-MOF precursor with enhanced electrochemical property

NASA Astrophysics Data System (ADS)

Lv, Zijian; Zhong, Qin; Bu, Yunfei

2018-05-01

Owing to the metalloid characteristic and superior electrical conductivity, the metal phosphides have received increasing interests in energy storage systems. Here, xrGO/Ni2P composites are successfully synthesized via an In-situ phosphorization process with GO/Ni-MOF as precursors. Compared to pure Ni2P, the xrGO/Ni2P composites appear enhanced electrochemical properties in terms of the specific capacitance and cycling performance as electrodes for supercapacitors. Especially, the 2rGO/Ni2P electrode shows a highest specific capacitance of 890 F g-1 at 1 A g-1 among the obtained composites. The enhancement can be attributed to the inherited structure from Ni-MOF and the well assembled of rGO and Ni2P through the In-situ conversion process. Moreover, when applied as positive electrode in a hybrid supercapacitor, an energy density of 35.9 W h kg-1 at a power density of 752 W kg-1 has been achieved. This work provides an In-situ conversion strategy for the synthesis of rGO/Ni2P composite which might be a promising electrode material for SCs.

3D hybrid integrated lasers for silicon photonics

NASA Astrophysics Data System (ADS)

Song, B.; Pinna, S.; Liu, Y.; Megalini, L.; Klamkin, J.

2018-02-01

A novel 3D hybrid integration platform combines group III-V materials and silicon photonics to yield high-performance lasers is presented. This platform is based on flip-chip bonding and vertical optical coupling integration. In this work, indium phosphide (InP) devices with monolithic vertical total internal reflection turning mirrors were bonded to active silicon photonic circuits containing vertical grating couplers. Greater than 2 mW of optical power was coupled into a silicon waveguide from an InP laser. The InP devices can also be bonded directly to the silicon substrate, providing an efficient path for heat dissipation owing to the higher thermal conductance of silicon compared to InP. Lasers realized with this technique demonstrated a thermal impedance as low as 6.2°C/W, allowing for high efficiency and operation at high temperature. InP reflective semiconductor optical amplifiers were also integrated with 3D hybrid integration to form integrated external cavity lasers. These lasers demonstrated a wavelength tuning range of 30 nm, relative intensity noise lower than -135 dB/Hz and laser linewidth of 1.5 MHz. This platform is promising for integration of InP lasers and photonic integrated circuits on silicon photonics.

Amplifier based broadband pixel for sub-millimeter wave imaging

NASA Astrophysics Data System (ADS)

Sarkozy, Stephen; Drewes, Jonathan; Leong, Kevin M. K. H.; Lai, Richard; Mei, X. B. (Gerry); Yoshida, Wayne; Lange, Michael D.; Lee, Jane; Deal, William R.

2012-09-01

Broadband sub-millimeter wave technology has received significant attention for potential applications in security, medical, and military imaging. Despite theoretical advantages of reduced size, weight, and power compared to current millimeter wave systems, sub-millimeter wave systems have been hampered by a fundamental lack of amplification with sufficient gain and noise figure properties. We report a broadband pixel operating from 300 to 340 GHz, biased off a single 2 V power supply. Over this frequency range, the amplifiers provide > 40 dB gain and <8 dB noise figure, representing the current state-of-art performance capabilities. This pixel is enabled by revolutionary enhancements to indium phosphide (InP) high electron mobility transistor technology, based on a sub-50 nm gate and indium arsenide composite channel with a projected maximum oscillation frequency fmax>1.0 THz. The first sub-millimeter wave-based images using active amplification are demonstrated as part of the Joint Improvised Explosive Device Defeat Organization Longe Range Personnel Imager Program. This development and demonstration may bring to life future sub-millimeter-wave and THz applications such as solutions to brownout problems, ultra-high bandwidth satellite communication cross-links, and future planetary exploration missions.

Preparation of NiCoP Hollow Quasi-Polyhedra and Their Electrocatalytic Properties for Hydrogen Evolution in Alkaline Solution.

PubMed

Li, Yapeng; Liu, Jindou; Chen, Chen; Zhang, Xiaohua; Chen, Jinhua

2017-02-22

Double metal phosphide (NiCoP) with hollow quasi-polyhedron structure was prepared by acidic etching and precipitation of ZIF-67 polyhedra and further phosphorization treatment with NaH 2 PO 2 . The morphology and microstructure of NiCoP quasi-polyhedron and its precursors were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and a micropore and chemisorption analyzer. Electrocatalytic properties were examined by typical electrochemical methods, such as linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy in 1.0 M KOH aqueous solution. Results reveal that, compared with CoP hollow polyhedra, NiCoP hollow quasi-polyhedra exhibit better electrochemical properties for hydrogen evolution with a low onset overpotential of 74 mV and a small Tafel slope of 42 mV dec -1 . When the current density is 10 mA cm -2 , the corresponding overpotential is merely 124 mV, and 93% of its electrocatalytic activity can be maintained for 12 h. This indicates that NiCoP with hollow quasi-polyhedron structure, bimetallic merit, and low cost may be a good candidate as electrocatalyst in the practical application of hydrogen evolution.

Chip-scale white flip-chip light-emitting diode containing indium phosphide/zinc selenide quantum dots

NASA Astrophysics Data System (ADS)

Fan, Bingfeng; Yan, Linchao; Lao, Yuqin; Ma, Yanfei; Chen, Zimin; Ma, Xuejin; Zhuo, Yi; Pei, Yanli; Wang, Gang

2017-08-01

A method for preparing a quantum dot (QD)-white light-emitting diode (WLED) is reported. Holes were etched in the SiO2 layer deposited on the sapphire substrate of the flip-chip LED by inductively coupled plasma, and these holes were then filled with QDs. An ultraviolet-curable resin was then spin-coated on top of the QD-containing SiO2 layer, and the resin was cured to act as a protecting layer. The reflective sidewall structure minimized sidelight leakage. The fabrication of the QD-WLED is simple in preparation and compatible with traditional LED processes, which was the minimum size of the WLED chip-scale integrated package. InP/ZnS core-shell QDs were used as the converter in the WLED. A blue light-emitting diode with a flip-chip structure was used as the excitation source. The QD-WLED exhibited color temperatures from 5900 to 6400 K and Commission Internationale De L'Elcairage color coordinates from (0.315, 0.325) to (0.325, 0.317), under drive currents from 100 to 400 mA. The QD-WLED exhibited stable optoelectronic properties.

Clinical use of photodynamic antimicrobial chemotherapy for the treatment of deep carious lesions

NASA Astrophysics Data System (ADS)

Guglielmi, Camila De Almeida B.; Simionato, Maria Regina L.; Ramalho, Karen Müller; Imparato, José Carlos P.; Pinheiro, Sérgio Luiz; Luz, Maria A. A. C.

2011-08-01

The purpose of this study was to assess photodynamic antimicrobial chemotherapy (PACT) via irradiation, using a low power laser associated with a photosensitization dye, as an alternative to remove cariogenic microorganisms by drilling. Remaining dentinal samples in deep carious lesions on permanent molars (n = 26) were treated with 0.01% methylene blue dye and irradiated with a low power laser (InGaAIP - indium gallium aluminum phosphide; λ = 660 nm; 100 mW; 320 Jcm-2 90 s; 9J). Samples of dentin from the pulpal wall region were collected with a micropunch before and immediately after PACT and kept in a transport medium for microbiological analysis. Samples were cultured in plates of Brucella blood agar, Mitis Salivarius Bacitracin agar and Rogosa SL agar to determine the total viable bacteria, mutans streptococci and Lactobacillus spp. counts, respectively. After incubation, colony-forming units were counted and microbial reduction was calculated for each group of bacteria. PACT led to statistically significant reductions in mutans streptococci (1.38 log), Lactobacillus spp. (0.93 log), and total viable bacteria (0.91 log). This therapy may be an appropriate approach for the treatment of deep carious lesions using minimally invasive procedures.

High-Efficiency Nanowire Solar Cells with Omnidirectionally Enhanced Absorption Due to Self-Aligned Indium-Tin-Oxide Mie Scatterers.

PubMed

van Dam, Dick; van Hoof, Niels J J; Cui, Yingchao; van Veldhoven, Peter J; Bakkers, Erik P A M; Gómez Rivas, Jaime; Haverkort, Jos E M

2016-12-27

Photovoltaic cells based on arrays of semiconductor nanowires promise efficiencies comparable or even better than their planar counterparts with much less material. One reason for the high efficiencies is their large absorption cross section, but until recently the photocurrent has been limited to less than 70% of the theoretical maximum. Here we enhance the absorption in indium phosphide (InP) nanowire solar cells by employing broadband forward scattering of self-aligned nanoparticles on top of the transparent top contact layer. This results in a nanowire solar cell with a photovoltaic conversion efficiency of 17.8% and a short-circuit current of 29.3 mA/cm 2 under 1 sun illumination, which is the highest reported so far for nanowire solar cells and among the highest reported for III-V solar cells. We also measure the angle-dependent photocurrent, using time-reversed Fourier microscopy, and demonstrate a broadband and omnidirectional absorption enhancement for unpolarized light up to 60° with a wavelength average of 12% due to Mie scattering. These results unambiguously demonstrate the potential of semiconductor nanowires as nanostructures for the next generation of photovoltaic devices.

One-step facile synthesis of Ni2P/C as cathode material for Ni/Zn aqueous secondary battery

NASA Astrophysics Data System (ADS)

Li, JiLan; Chen, ChangGuo

2018-01-01

Nickel phosphides/carbon(Ni2P/C) composites have been successfully synthesized via a simple one-pot hydrothermal method using glucose as carbon source for the first time. By contrast, the pure Ni2P was prepared under the same conditions without glucose. The results show that glucose not only provide the carbon source, but also prevent the aggregation of Ni2P particles. The as-obtained Ni2P/C composites and pure Ni2P were used as cathode material for alkaline Ni/Zn battery. Owing to unique Ni2P/C composites and loose, Ultra thin flower-like shape the synthesized Ni2P/C material delivers high capacity of 176 mAh g-1 at 1 A g-1 and 82 mAh g-1 at 5 A g-1 current density in Ni2P/C-Zn battery. Moreover, it shows a good cycling life that capacity fading only about 6.2% after 1500 cycles. All of these indicate that the prepared Ni2P/C composites may be a new promising cathode material for Ni-Zn rechargeable battery.

Hexanuclear gold(I) phosphide complexes as platforms for multiple redox-active ferrocenyl units.

PubMed

Lee, Terence Kwok-Ming; Cheng, Eddie Chung-Chin; Zhu, Nianyong; Yam, Vivian Wing-Wah

2014-01-03

The synthesis, X-ray crystal structures, electrochemical, and spectroscopic studies of a series of hexanuclear gold(I) μ(3)-ferrocenylmethylphosphido complexes stabilized by bridging phosphine ligands, [Au(6)(P-P)(n)(Fc-CH(2)-P)(2)][PF(6)](2) (n=3, P-P=dppm (bis(diphenylphosphino)methane) (1), dppe (1,2-bis(diphenylphosphino)ethane) (2), dppp (1,3-bis(diphenylphosphino)propane) (3), Ph(2)PN(C(3)H(7))-PPh(2) (4), Ph(2)PN(Ph-CH(3)-p)PPh(2) (5), dppf (1,1′-bis(diphenylphosphino)ferrocene) (6); n=2, P-P=dpepp (bis(2-diphenylphosphinoethyl)phenylphosphine) (7)), as platforms for multiple redox-active ferrocenyl units, are reported. The investigation of the structural changes of the clusters has been probed by introducing different bridging phosphine ligands. This class of gold(I) μ(3)-ferrocenylmethylphosphido complexes has been found to exhibit one reversible oxidation couple, suggestive of the absence of electronic communication between the ferrocene units through the Au(6)P(2) cluster core, providing an understanding of the electronic properties of the hexanuclear Au(I) cluster linkage. The present complexes also serve as an ideal system for the design of multi-electron reservoir and molecular battery systems.

Effective Integration of Targeted Tumor Imaging and Therapy Using Functionalized InP QDs with VEGFR2 Monoclonal Antibody and miR-92a Inhibitor.

PubMed

Wu, Yi-Zhou; Sun, Jie; Zhang, Yaqin; Pu, Maomao; Zhang, Gen; He, Nongyue; Zeng, Xin

2017-04-19

Rapid diagnosis and targeted drug treatment require agents that possess multiple functions. Nanomaterials that facilitate optical imaging and direct drug delivery have shown great promise for effective cancer treatment. In this study, we first modified near-infrared fluorescent indium phosphide quantum dots (InP QDs) with a vascular endothelial growth factor receptor 2 (VEGFR2) monoclonal antibody to afford targeted drug delivery function. Then, a miR-92a inhibitor, an antisense microRNA that enhances the expression of tumor suppressor p63, was attached to the VEGFR2-InP QDs via electrostatic interactions. The functionalized InP nanocomposite (IMAN) selectively targets tumor sites and allows for infrared imaging in vivo. We further explored the mechanism of this active targeting. The IMAN was endocytosed and delivered in the form of microvesicles via VEGFR2-CD63 signaling. Moreover, the IMAN induced apoptosis of human myelogenous leukemia cells through the p63 pathway in vitro and in vivo. These results indicate that the IMAN may provide a new and promising chemotherapy strategy against cancer cells, particularly by its active targeting function and utility in noninvasive three-dimensional tumor imaging.

A high-coverage nanoparticle monolayer for the fabrication of a subwavelength structure on InP substrates.

PubMed

Kim, Dae-Seon; Park, Min-Su; Jang, Jae-Hyung

2011-08-01

Subwavelength structures (SWSs) were fabricated on the Indium Phosphide (InP) substrate by utilizing the confined convective self-assembly (CCSA) method followed by reactive ion etching (RIE). The surface condition of the InP substrate was changed by depositing a 30-nm-thick SiO2 layer and subsequently treating the surface with O2 plasma to achieve better surface coverage. The surface coverage of nanoparticle monolayer reached 90% by using O2 plasma-treated SiO2/InP substrate among three kinds of starting substrates such as the bare InP, SiO2/InP and O2 plasma-treated SiO2/InP substrate. A nanoparticle monolayer consisting of polystyrene spheres with diameter of 300 nm was used as an etch mask for transferring a two-dimensional periodic pattern onto the InP substrate. The fabricated conical SWS with an aspect ratio of 1.25 on the O2 plasma-treated SiO2/InP substrate exhibited the lowest reflectance. The average reflectance of the conical SWS was 5.84% in a spectral range between 200 and 900 nm under the normal incident angle.

Analysis of different types of poisoning in a tertiary care hospital in rural South India.

PubMed

Jaiprakash, Heethal; Sarala, N; Venkatarathnamma, P N; Kumar, T N

2011-01-01

The global problem of acute poisoning has steadily increased over the past few years. It is an important cause of morbidity and mortality in developing countries. Better preventive and management strategies can be developed if the incidence and pattern of acute poisoning is known. The study aims at analyzing the pattern, cause and mortality rate of poisoning. The study was conducted in a rural area in South India. This retrospective study was conducted from January 2003-December 2003. The data was analysed using descriptive statistics. Out of the 225 cases 139 were males and 86 females. Poisoning was common in the age group of 21-30 years which was 84 cases and 11-20 years was 73 cases. The poisons consumed were as follows: Organophosphorous 135 cases, aluminum and zinc phosphide 50 cases, phenobarbitone 18 cases, benzodiazepines 7 cases, paracetamol 2 cases, miscellaneous 13 cases. 94% were suicides and 6% accidental. Mortality rate was 12.8%. Establishment of strict policies against the sale and availability of pesticides and over the counter drugs is an effective way to control organophosphorous and drug poisoning. Copyright © 2010 Elsevier Ltd. All rights reserved.

Self-supported Zn3P2 nanowire arrays grafted on carbon fabrics as an advanced integrated anode for flexible lithium ion batteries

NASA Astrophysics Data System (ADS)

Li, Wenwu; Gan, Lin; Guo, Kai; Ke, Linbo; Wei, Yaqing; Li, Huiqiao; Shen, Guozhen; Zhai, Tianyou

2016-04-01

We, for the first time, successfully grafted well-aligned binary lithium-reactive zinc phosphide (Zn3P2) nanowire arrays on carbon fabric cloth by a facile CVD method. When applied as a novel self-supported binder-free anode for lithium ion batteries (LIBs), the hierarchical three-dimensional (3D) integrated anode shows excellent electrochemical performances: a highly reversible initial lithium storage capacity of ca. 1200 mA h g-1 with a coulombic efficiency of up to 88%, a long lifespan of over 200 cycles without obvious decay, and a high rate capability of ca. 400 mA h g-1 capacity retention at an ultrahigh rate of 15 A g-1. More interestingly, a flexible LIB full cell is assembled based on the as-synthesized integrated anode and the commercial LiFePO4 cathode, and shows striking lithium storage performances very close to the half cells: a large reversible capacity over 1000 mA h g-1, a long cycle life of over 200 cycles without obvious decay, and an ultrahigh rate performance of ca. 300 mA h g-1 even at 20 A g-1. Considering the excellent lithium storage performances of coin-type half cells as well as flexible full cells, the as-prepared carbon cloth grafted well-aligned Zn3P2 nanowire arrays would be a promising integrated anode for flexible LIB full cell devices.We, for the first time, successfully grafted well-aligned binary lithium-reactive zinc phosphide (Zn3P2) nanowire arrays on carbon fabric cloth by a facile CVD method. When applied as a novel self-supported binder-free anode for lithium ion batteries (LIBs), the hierarchical three-dimensional (3D) integrated anode shows excellent electrochemical performances: a highly reversible initial lithium storage capacity of ca. 1200 mA h g-1 with a coulombic efficiency of up to 88%, a long lifespan of over 200 cycles without obvious decay, and a high rate capability of ca. 400 mA h g-1 capacity retention at an ultrahigh rate of 15 A g-1. More interestingly, a flexible LIB full cell is assembled based on the as-synthesized integrated anode and the commercial LiFePO4 cathode, and shows striking lithium storage performances very close to the half cells: a large reversible capacity over 1000 mA h g-1, a long cycle life of over 200 cycles without obvious decay, and an ultrahigh rate performance of ca. 300 mA h g-1 even at 20 A g-1. Considering the excellent lithium storage performances of coin-type half cells as well as flexible full cells, the as-prepared carbon cloth grafted well-aligned Zn3P2 nanowire arrays would be a promising integrated anode for flexible LIB full cell devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08467a

Germylenes and stannylenes stabilized within N2PE rings (E = Ge or Sn): combined experimental and theoretical study.

PubMed

Vrána, Jan; Ketkov, Sergey; Jambor, Roman; Růžička, Aleš; Lyčka, Antonín; Dostál, Libor

2016-06-21

The deprotonation of aminophosphanes PhP(NHR)2 (R = t-Bu or Dip; Dip = 2,6-i-Pr2C6H3) and t-BuP(NHDip)2 using n-BuLi gave, depending on the stoichiometry, both the dilithium compounds {[PhP(Nt-Bu)2]Li2}2 (), [PhP(Nt-Bu)(NDip)]Li2·(Et2O) (), [t-BuP(NDip)2]Li2·(Et2O)2 () and [t-BuP(NDip)2]Li2·(tmeda)2 (), and the monolithium compounds [PhP(NHt-Bu)(NR)]Li·(tmeda) (R = t-Bu , Dip ) and [t-BuP(NHDip)(NDip)]Li·(tmeda) (). Treatment of , and with GeCl2·dioxane or SnCl2 in a 1 : 1 stoichiometric ratio gave the corresponding tetrylenes [PhP(Nt-Bu)2]E (E = Ge , Sn ), [PhP(Nt-Bu)(NDip)]Ge () and [t-BuP(NDip)2]E (E = Ge , Sn ). The heteroleptic germylene [Ph(H)P(Nt-Bu)2]GeCl () was obtained by the reaction of the monolithium compound [PhP(NHt-Bu)(Nt-Bu)]Li·(tmeda) () with GeCl2·dioxane in a 1 : 1 stoichiometric ratio, as a result of a spontaneous NH → PH tautomeric shift in the ligand backbone. In contrast, an analogous reaction with SnCl2 produced only stannylene along with the PhP(NHt-Bu)2 starting material, suggesting scrambling of the ligands rather than a NH → PH tautomeric shift. Finally, heating in solution led to P-C bond cleavage and formation of the bis(imino)phosphide [DipNPNDip]Li·(tmeda) (). The reaction of with GeCl2·dioxane, SnCl2 or PbCl2 in a 2 : 1 stoichiometric ratio yielded the unprecedented tetrylenes [DipNPNDip]2E (E = Ge , Sn and Pb ), in which the tetrylene center is incorporated within two N2PE rings. Treatment of the monolithium compound with n-BuLi and K (or KC8) gave [t-BuNPNt-Bu]Li·(tmeda) () and{[t-BuNPNt-Bu]K(tmeda)}2 (), respectively. In contrast to the reaction with , similar reactions of with GeCl2·dioxane and SnCl2 resulted in the known compounds cis-[P(μ-Nt-Bu)2P(t-BuN)2]E (E = Ge, Sn); evidently the t-Bu groups do not provide sufficient steric shielding to protect the bis(imino)phosphide backbone as in the case of . The bonding situation in a set of selected compounds (, ) has been subjected to a theoretical survey with particular emphasis on the nature of the bonding between the ligand and the central metal and the bonding within the NPN core of the ligand, showing significant differences among the studied complexes.

An Infrared Spectroscopic Study Toward the Formation of Alkylphosphonic Acids and Their Precursors in Extraterrestrial Environments

NASA Astrophysics Data System (ADS)

Turner, Andrew M.; Abplanalp, Matthew J.; Blair, Tyler J.; Dayuha, Remwilyn; Kaiser, Ralf I.

2018-01-01

The only known phosphorus-containing organic compounds of extraterrestrial origin, alkylphosphonic acids, were discovered in the Murchison meteorite and have accelerated the hypothesis that reduced oxidation states of phosphorus were delivered to early Earth and served as a prebiotic source of phosphorus. While previous studies looking into the formation of these alkylphosphonic acids have focused on the iron–nickel phosphide mineral schreibersite and phosphorous acid as a source of phosphorus, this work utilizes phosphine (PH3), which has been discovered in the circumstellar envelope of IRC +10216, in the atmosphere of Jupiter and Saturn, and believed to be the phosphorus carrier in comet 67P/Churyumov–Gerasimenko. Phosphine ices prepared with interstellar molecules such as carbon dioxide, water, and methane were subjected to electron irradiation, which simulates the secondary electrons produced from galactic cosmic rays penetrating the ice, and probed using infrared spectroscopy to understand the possible formation of alkylphosphonic acids and their precursors on interstellar icy grains that could become incorporated into meteorites such as Murchison. We present the first study and results on the possible synthesis of alkylphosphonic acids produced from phosphine-mixed ices under interstellar conditions. All functional groups of alkylphosphonic acids were detected through infrared spectroscopically, suggesting that this class of molecules can be formed in interstellar ices.

Mechanical strength and tribological behavior of ion-beam deposited boron nitride films on non-metallic substrates

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Buckley, Donald H.; Pouch, John J.; Alterovitz, Samuel A.; Sliney, Harold E.

1987-01-01

An investigation was conducted to examine the mechanical strength and tribological properties of boron nitride (BN) films ion-beam deposited on silicon (Si), fused silica (SiO2), gallium arsenide (GaAs), and indium phosphide (InP) substrates in sliding contact with a diamond pin under a load. The results of the investigation indicate that BN films on nonmetallic substrates, like metal films on metallic substrates, deform elastically and plastically in the interfacial region when in contact with a diamond pin. However, unlike metal films and substrates, BN films on nonmetallic substrates can fracture when they are critically loaded. Not only does the yield pressure (hardness) of Si and SiO2 substrates increase by a factor of 2 in the presence of a BN film, but the critical load needed to fracture increases as well. The presence of films on the brittle substrates can arrest crack formation. The BN film reduces adhesion and friction in the sliding contact. BN adheres to Si and SiO2 and forms a good quality film, while it adheres poorly to GaAs and InP. The interfacial adhesive strengths were 1 GPa for a BN film on Si and appreciably higher than 1 GPa for a BN film on SiO2.

Synthesis of actinide nitrides, phosphides, sulfides and oxides

DOEpatents

Van Der Sluys, William G.; Burns, Carol J.; Smith, David C.

1992-01-01

A process of preparing an actinide compound of the formula An.sub.x Z.sub.y wherein An is an actinide metal atom selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, x is selected from the group consisting of one, two or three, Z is a main group element atom selected from the group consisting of nitrogen, phosphorus, oxygen and sulfur and y is selected from the group consisting of one, two, three or four, by admixing an actinide organometallic precursor wherein said actinide is selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, a suitable solvent and a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, at temperatures and for time sufficient to form an intermediate actinide complex, heating said intermediate actinide complex at temperatures and for time sufficient to form the actinide compound, and a process of depositing a thin film of such an actinide compound, e.g., uranium mononitride, by subliming an actinide organometallic precursor, e.g., a uranium amide precursor, in the presence of an effectgive amount of a protic Lewis base, e.g., ammonia, within a reactor at temperatures and for time sufficient to form a thin film of the actinide compound, are disclosed.

Noncrystalline structure of Ni-P nanoparticles prepared by liquid pulse discharge.

PubMed

Tan, Yuanyuan; Yu, Hongying; Wu, Zhonghua; Yang, Bin; Gong, Yu; Yan, Shi; Du, Rong; Chen, Zhongjun; Sun, Dongbai

2015-03-01

Noncrystalline nickel phosphide (Ni-P) nanoparticles have drawn great attention due to their high potential as catalysts. However, the structure of noncrystalline Ni-P nanoparticles is still unknown, which may shed light on explaining the catalysis mechanism of the Ni-P nanoparticles. In this paper, noncrystalline Ni-P nanoparticles were synthesized. Their morphology, particle size, element contents, local atomic structures, as well as the catalysis in the thermal decomposition of ammonium perchlorate were studied. The results demonstrate that the as-prepared Ni-P nanoparticles are spherical with an average diameter of about 13.5 nm. The Ni and P contents are, respectively, 78.15% and 21.85%. The noncrystalline nature of the as-prepared Ni-P nanoparticles can be attributed to cross-linkage between P-doping f.c.c.-like Ni centers and Ni3P-like P centers. The locally ordered Ni centers and P centers are the nuclei sites, which can explain well the origin of initial nuclei to form the crystalline phases after high-temperature annealing. The starting temperature of high-temperature decomposition of ammonium perchlorate was found having a significant decrease in the presence of the noncrystalline Ni-P nanoparticles. Therefore, the as-prepared noncrystalline Ni-P nanoparticles can be used as a potential catalyst in the thermal decomposition of ammonium perchlorate.

A very low resistance, non-sintered contact system for use on indium phosphide concentrator/shallow junction solar cells

NASA Technical Reports Server (NTRS)

Weizer, Victor G.; Fatemi, Navid S.

1991-01-01

An investigation is made into the possibility of providing low resistance contacts to shallow junction InP solar cells which do not require sintering and which do not cause device degradation even when subjected to extended annealing at elevated temperatures. We show that the addition of In to Au contacts in amounts that exceed the solid solubility limit lowers the as-fabricated (unsintered) contact resistivity (R sub c) to the 10(exp -5) ohm cm(exp 2) range. We next consider the contact system Au/Au2P3 which has been shown to exhibit as-fabricated R sub c values in the 10(exp -6) ohm cm(exp 2) range, but which fails quickly when heated. We show that the substitution of a refractory metal (W, Ta) for Au preserves the low R sub c values while preventing the destructive reactions that would normally take place in this system at high temperatures. We show, finally, that R sub c values in the 10(exp -7) ohm cm(exp 2) range can be achieved without sintering by combining the effects of In or Ga additions to Au contacts with the effects of introducing a thin Au2P3 layer at the metal-InP interface.

Acute Pesticide Poisoning in Children: Hospital Review in Selected Hospitals of Tanzania.

PubMed

Lekei, Elikana; Ngowi, Aiwerasia V; London, Leslie

2017-01-01

Acute pesticide poisoning (APP) is a serious problem worldwide. Because the burden of childhood APP is unknown in Tanzania, this study describes the distribution, circumstances, and patterns of APP involving children under 18 years in Tanzania. A 12-month prospective study was conducted in 10 Tanzanian healthcare facilities in 2006 using a data collection tool for surveillance. Of 53 childhood poisoning cases identified, 56.6% were female. The most common poisoning circumstances were accidents (49.1%) and suicide (30.2%). The most vulnerable children were 16-17 years old (30.2%). Suicide was significantly more common in females (PRR females/males = 1.66; 95% CI = 1.03-2.68) and accidental cases were more common in children aged 10 years or younger. Suicide was concentrated in children over 10 years, comprising 53% of cases in this age group. Organophosphates (OPs), zinc phosphide, and endosulfan were common amongst reported poisoning agents. The annual APP incidence rate was 1.61/100,000. APP is common among children in this region of Tanzania. Prevention of suicide in older children should address mental health issues and control access to toxic pesticides. Prevention of accidents in younger children requires safer storage and hygiene measures. Diverse interventions are needed to reduce pesticide poisoning among children in Tanzania.

Mineralogy and petrography of C asteroid regolith: The Sutter's Mill CM meteorite

NASA Astrophysics Data System (ADS)

Zolensky, Michael; Mikouchi, Takashi; Fries, Marc; Bodnar, Robert; Jenniskens, Peter; Yin, Qing-zhu; Hagiya, Kenji; Ohsumi, Kazumasa; Komatsu, Mutsumi; Colbert, Matthew; Hanna, Romy; Maisano, Jessie; Ketcham, Richard; Kebukawa, Yoko; Nakamura, Tomoki; Matsuoka, Moe; Sasaki, Sho; Tsuchiyama, Akira; Gounelle, Matthieu; Le, Loan; Martinez, James; Ross, Kent; Rahman, Zia

2014-11-01

Based upon our characterization of three separate stones by electron and X-ray beam analyses, computed X-ray microtomography, Raman microspectrometry, and visible-IR spectrometry, Sutter's Mill is a unique regolith breccia consisting mainly of various CM lithologies. Most samples resemble existing available CM2 chondrites, consisting of chondrules and calcium-aluminum-rich inclusion (CAI) set within phyllosilicate-dominated matrix (mainly serpentine), pyrrhotite, pentlandite, tochilinite, and variable amounts of Ca-Mg-Fe carbonates. Some lithologies have witnessed sufficient thermal metamorphism to transform phyllosilicates into fine-grained olivine, tochilinite into troilite, and destroy carbonates. One finely comminuted lithology contains xenolithic materials (enstatite, Fe-Cr phosphides) suggesting impact of a reduced asteroid (E or M class) onto the main Sutter's Mill parent asteroid, which was probably a C class asteroid. One can use Sutter's Mill to help predict what will be found on the surfaces of C class asteroids such as Ceres and the target asteroids of the OSIRIS-REx and Hayabusa 2 sample return missions (which will visit predominantly primitive asteroids). C class asteroid regolith may well contain a mixture of hydrated and thermally dehydrated indigenous materials as well as a significant admixture of exogenous material would be essential to the successful interpretation of mineralogical and bulk compositional data.

Resonant Tunneling Analog-To-Digital Converter

NASA Technical Reports Server (NTRS)

Broekaert, T. P. E.; Seabaugh, A. C.; Hellums, J.; Taddiken, A.; Tang, H.; Teng, J.; vanderWagt, J. P. A.

1995-01-01

As sampling rates continue to increase, current analog-to-digital converter (ADC) device technologies will soon reach a practical resolution limit. This limit will most profoundly effect satellite and military systems used, for example, for electronic countermeasures, electronic and signal intelligence, and phased array radar. New device and circuit concepts will be essential for continued progress. We describe a novel, folded architecture ADC which could enable a technological discontinuity in ADC performance. The converter technology is based on the integration of multiple resonant tunneling diodes (RTD) and hetero-junction transistors on an indium phosphide substrate. The RTD consists of a layered semiconductor hetero-structure AlAs/InGaAs/AlAs(2/4/2 nm) clad on either side by heavily doped InGaAs contact layers. Compact quantizers based around the RTD offer a reduction in the number of components and a reduction in the input capacitance Because the component count and capacitance scale with the number of bits N, rather than by 2 (exp n) as in the flash ADC, speed can be significantly increased, A 4-bit 2-GSps quantizer circuit is under development to evaluate the performance potential. Circuit designs for ADC conversion with a resolution of 6-bits at 25GSps may be enabled by the resonant tunneling approach.

Acute Pesticide Poisoning in Children: Hospital Review in Selected Hospitals of Tanzania

PubMed Central

London, Leslie

2017-01-01

Background Acute pesticide poisoning (APP) is a serious problem worldwide. Because the burden of childhood APP is unknown in Tanzania, this study describes the distribution, circumstances, and patterns of APP involving children under 18 years in Tanzania. Methodology A 12-month prospective study was conducted in 10 Tanzanian healthcare facilities in 2006 using a data collection tool for surveillance. Results Of 53 childhood poisoning cases identified, 56.6% were female. The most common poisoning circumstances were accidents (49.1%) and suicide (30.2%). The most vulnerable children were 16-17 years old (30.2%). Suicide was significantly more common in females (PRR females/males = 1.66; 95% CI = 1.03–2.68) and accidental cases were more common in children aged 10 years or younger. Suicide was concentrated in children over 10 years, comprising 53% of cases in this age group. Organophosphates (OPs), zinc phosphide, and endosulfan were common amongst reported poisoning agents. The annual APP incidence rate was 1.61/100,000. Conclusion APP is common among children in this region of Tanzania. Prevention of suicide in older children should address mental health issues and control access to toxic pesticides. Prevention of accidents in younger children requires safer storage and hygiene measures. Diverse interventions are needed to reduce pesticide poisoning among children in Tanzania. PMID:29441090

Enhanced activity of Pt/CNTs anode catalyst for direct methanol fuel cells using Ni2P as co-catalyst

NASA Astrophysics Data System (ADS)

Li, Xiang; Luo, Lanping; Peng, Feng; Wang, Hongjuan; Yu, Hao

2018-03-01

The direct methanol fuel cell is a promising energy conversion device because of the utilization of the state-of-the-art platinum (Pt) anode catalyst. In this work, novel Pt/Ni2P/CNTs catalysts were prepared by the H2 reduction method. It was found that the activity and stability of Pt for methanol oxidation reaction (MOR) could be significantly enhanced while using nickel phosphide (Ni2P) nanoparticles as co-catalyst. X-ray photoelectron spectroscopy revealed that the existence of Ni2P affected the particle size and electronic distribution of Pt obviously. Pt/CNTs catalyst, Pt/Ni2P/CNTs catalysts with different Ni2P amount were synthesized, among which Pt/6%Ni2P/CNTs catalyst exhibited the best MOR activity of 1400 mAmg-1Pt, which was almost 2.5 times of the commercial Pt/C-JM catalyst. Moreover, compared to other Pt-based catalysts, this novel Pt/Ni2P/CNTs catalyst also exhibited higher onset current density and better steady current density. The result of this work may provide positive guidance to the research on high efficiency and stability of Pt-based catalyst for direct methanol fuel cells.

InP shallow-homojunction solar cells

NASA Technical Reports Server (NTRS)

Keavney, Christopher; Spitzer, Mark B.; Vernon, Stanley M.; Haven, Victor E.; Augustine, Godfrey

1989-01-01

Indium phosphide solar cells with very thin n-type emitters have been made by both ion implantation and metalorganic chemical vapor deposition. Air mass zero efficiencies as high as 18.8 percent (NASA measurement) have been achieved. Although calculations show that, as is the case with GaAs, a heterostructure is expected to be required for the highest efficiencies attainable, the material properties of InP give the shallow-homojunction structure a greater potential than in the case of GaAs. The best cells, which were those made by ion implantation, show open-circuit voltage (V sub oc) of 873 mV, short-circuit current of 357 A/sq m (35.7 mA/sq cm), and fill factor of 0.829. Improvements are anticipated in all three of these parameters. Internal quantum efficiency peaks at over 90 percent in the red end of the spectrum, but drops to 54 percent in the blue end. Other cells have achieved 74 percent in the blue end. Detailed modeling of the data indicates that a high front surface recombination velocity is responsible for the low blue response, that the carrier lifetime is high enough to allow good carrier collection from both the base and the emitter, and that the voltage is base-limited.

Radiation and temperature effects in gallium arsenide, indium phosphide and silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Statler, R. L.

1987-01-01

The effects of radiation on performance are determined for both n(+)p and p(+)n GaAs and InP cells and for silicon n(+)p cells. It is found that the radiation resistance of InP is greater than that of both GaAs and Si under 1 MeV electron irradiation. For silicon, the observed decreased radiation resistance with decreased resistivity is attributed to the presence of a radiation induced boron-oxygen defect. Comparison of radiation damage in both p(+)n and n(+)p GaAs cells yields a decreased radiation resistance for the n(+)p cell attributable to increased series resistance, decreased shunt resistance, and relatively greater losses in the cell's p-region. For InP, the n(+)p configuration is found to have greater radiation resistance than the p(+)n cell. The increased loss in this latter cell is attributed to losses in the cell's emitter region. Temperature dependency results are interpreted using a theoretical relation for dVoc/cT which predicts that increased Voc should results in decreased numerical values for dPm/dT. The predicted correlation is observed for GaAs but not for InP a result which is attributed to variations in cell processing.

Radiation and temperature effects in gallium arsenide, indium phosphide, and silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.; Statler, R. L.

1987-01-01

The effects of radiation on performance are determined for both n+p and p+n GaAs and InP cells and for silicon n+p cells. It is found that the radiation resistance of InP is greater than that of both GaAs and Si under 1-MeV electron irradiation. For silicon, the observed decreased radiation resistance with decreased resistivity is attributed to the presence of a radiation-induced boron-oxygen defect. Comparison of radiation damage in both p+n and n+p GaAs cells yields a decreased radiation resistance for the n+p cell attributable to increased series resistance, decreased shunt resistance, and relatively greater losses in the cell's p-region. For InP, the n+p configuration is found to have greater radiation resistance than the p+n cell. The increased loss in this latter cell is attributed to losses in the cell's emitter region. Temperature dependency results are interpreted using a theoretical relation for dVoc/dT, which predicts that increased Voc should result in decreased numerical values for dPm/dT. The predicted correlation is observed for GaAs but not for InP, a result which is attributed to variations in cell processing.

Native gallium adatoms discovered on atomically-smooth gallium nitride surfaces at low temperature.

PubMed

Alam, Khan; Foley, Andrew; Smith, Arthur R

2015-03-11

In advanced compound semiconductor devices, such as in quantum dot and quantum well systems, detailed atomic configurations at the growth surfaces are vital in determining the structural and electronic properties. Therefore, it is important to investigate the surface reconstructions in order to make further technological advancements. Usually, conventional semiconductor surfaces (e.g., arsenides, phosphides, and antimonides) are highly reactive due to the existence of a high density of group V (anion) surface dangling bonds. However, in the case of nitrides, group III rich growth conditions in molecular beam epitaxy are usually preferred leading to group III (Ga)-rich surfaces. Here, we use low-temperature scanning tunneling microscopy to reveal a uniform distribution of native gallium adatoms with a density of 0.3%-0.5% of a monolayer on the clean, as-grown surface of nitrogen polar GaN(0001̅) having the centered 6 × 12 reconstruction. Unseen at room temperature, these Ga adatoms are strongly bound to the surface but move with an extremely low surface diffusion barrier and a high density saturation coverage in thermodynamic equilibrium with Ga droplets. Furthermore, the Ga adatoms reveal an intrinsic surface chirality and an asymmetric site occupation. These observations can have important impacts in the understanding of gallium nitride surfaces.