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1

E-Print Network 3.0 - arsenide-based ternary compounds Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

gallium arsenide-based... separately claimed breakthroughs in solar cell production. Gallium arsenide (GaAs) and related compounds... of manufacturing compound semiconductors...

2

FGD gypsum issues  

SciTech Connect

The article first explains how gypsum by-product is produced in flue gas desulfurization systems in coal-fired power plants. It goes on to talk about the main markets for gypsum - wallboard manufacture (Plaster of Paris), cement production and soil stabilization. In the USA in 2006 41.6 million tons of gypsum was used by manufacturers of wallboard and plaster products, 3.0 mt for cement production and 1.1 mt for agricultural purposes. A method of determining the by-product gypsum content by thermogravimetric analysis is outlined. 4 refs., 1 fig.

Buecker, B.

2007-11-15T23:59:59.000Z

3

Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire-array  

E-Print Network (OSTI)

Optical, electrical, and solar energy-conversion properties of gallium arsenide nanowire, and will aid in the design and optimization of nanowire-based systems for solar energy-conversion applications, and the photoelectrochemical energy-conversion properties of GaAs nanowire arrays were evaluated in contact with one

Zhou, Chongwu

4

Simple intrinsic defects in GaAs : numerical supplement.  

SciTech Connect

This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory calculations of properties of simple intrinsic defects in gallium arsenide are presented.

Schultz, Peter Andrew

2012-04-01T23:59:59.000Z

5

J. Phys. III Yance 7 (1997) 1495-1503 JULY 1997, PAGE 1495 Interaction of Copper with Dislocations in GaAs  

E-Print Network (OSTI)

. The interaction of copper with dislocations was studied in silicon-doped gallium arsenide by means growth or subsequent processing steps ill. In gallium arsenide, copper has two levels in the band gap solubility of Cu in GaAs at room temperature. The electrically inactive copper forms precipitates [3

Boyer, Edmond

6

The development of integrated chemical microsensors in GaAs  

SciTech Connect

Monolithic, integrated acoustic wave chemical microsensors are being developed on gallium arsenide (GaAs) substrates. With this approach, arrays of microsensors and the high frequency electronic components needed to operate them reside on a single substrate, increasing the range of detectable analytes, reducing overall system size, minimizing systematic errors, and simplifying assembly and packaging. GaAs is employed because it is both piezoelectric, a property required to produce the acoustic wave devices, and a semiconductor with a mature microelectronics fabrication technology. Many aspects of integrated GaAs chemical sensors have been investigated, including: surface acoustic wave (SAW) sensors; monolithic SAW delay line oscillators; GaAs application specific integrated circuits (ASIC) for sensor operation; a hybrid sensor array utilizing these ASICS; and the fully monolithic, integrated SAW array. Details of the design, fabrication, and performance of these devices are discussed. In addition, the ability to produce heteroepitaxial layers of GaAs and aluminum gallium arsenide (AlGaAs) makes possible micromachined membrane sensors with improved sensitivity compared to conventional SAW sensors. Micromachining techniques for fabricating flexural plate wave (FPW) and thickness shear mode (TSM) microsensors on thin GaAs membranes are presented and GaAs FPW delay line and TSM resonator performance is described.

CASALNUOVO,STEPHEN A.; ASON,GREGORY CHARLES; HELLER,EDWIN J.; HIETALA,VINCENT M.; BACA,ALBERT G.; HIETALA,S.L.

1999-11-01T23:59:59.000Z

7

Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module  

SciTech Connect

We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

Silverman, T. J.; Deceglie, M. G.; Marion, B.; Cowley, S.; Kayes, B.; Kurtz, S.

2013-06-01T23:59:59.000Z

8

Ultraslow growth rates of giant gypsum crystals  

Science Journals Connector (OSTI)

...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject in mineral...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject...

A. E. S. Van Driessche; J. M. García-Ruíz; K. Tsukamoto; L. D. Patiño-Lopez; H. Satoh

2011-01-01T23:59:59.000Z

9

DEFORMATIONAL KINKS IN BRUCITE AND GYPSUM  

Science Journals Connector (OSTI)

DEFORMATIONAL KINKS IN BRUCITE AND GYPSUM Francis J. Turner Lionel...CALIFORNIA, BERKELEY DEFORMATIONAL KINKS IN BRUCITE AND GYPSUM. | DEPARTMENT OF GEOLOGY...cgi/georef/georef;1966012724 brucite Brucite and gypsum crystal structure...

Francis J. Turner; Lionel E. Weiss

1965-01-01T23:59:59.000Z

10

Deprotecting Thioacetyl-Terminated Terphenyldithiol for Assembly on Gallium Arsenide  

SciTech Connect

We characterize the assembly of terphenyldithiol (TPDT) on gallium arsenide (GaAs) from ethanol (EtOH) and tetrahydrofuran (THF) as a function of ammonium hydroxide (NH4OH) concentration. NH4OH facilitates the conversion of thioacetyl end groups of the TPDT precursor to thiolates in the assembly solution. The final structure of TPDT assembled on GaAs is sensitive not only to the assembly solvent but also to NH4OH concentration. In the presence of low concentrations of NH4OH (1 mM), TPDT assemblies from EtOH are oriented upright. The same assemblies are less upright when adsorption is carried out at higher NH4OH concentrations. In THF, TPDT does not adsorb significantly on GaAs at low NH4OH concentrations. The surface coverage and structural organization of these assemblies improve with increasing NH4OH concentrations, although these assemblies are never as organized as those from EtOH. The difference in the final structure of TPDT assemblies is attributed to differences in the thiolate fraction in the assembly solution at the point of substrate immersion.

Krapchetov,D.; Ma, H.; Jen, A.; Fischer, D.; Loo, Y.

2008-01-01T23:59:59.000Z

11

Analytic bond-order potential for the gallium arsenide system  

Science Journals Connector (OSTI)

An analytic, bond-order potential (BOP) is proposed and parametrized for the gallium arsenide system. The potential addresses primary (?) and secondary (?) bonding and the valence-dependent character of heteroatomic bonding, and it can be combined with an electron counting potential to address the distribution of electrons on the GaAs surface. The potential was derived from a tight-binding description of covalent bonding by retaining the first two levels of an expanded Green’s function for the ? and ? bond-order terms. Predictions using the potential were compared with independent estimates for the structures and binding energy of small clusters (dimers, trimers, and tetramers) and for various bulk lattices with coordinations varying from 4 to 12. The structure and energies of simple point defects and melting transitions were also investigated. The relative stabilities of the (001) surface reconstructions of GaAs were well predicted, especially under high-arsenic-overpressure conditions. The structural and binding energy trends of this GaAs BOP generally match experimental observations and ab initio calculations.

D. A. Murdick; X. W. Zhou; H. N. G. Wadley; D. Nguyen-Manh; R. Drautz; D. G. Pettifor

2006-01-20T23:59:59.000Z

12

Ultraslow growth rates of giant gypsum crystals  

Science Journals Connector (OSTI)

...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject in mineral...gypsum crystals of Naica ore mines in Chihuahua, Mexico, a challenging subject in...geological timescale. age anhydrite Chihuahua Mexico cooling crystal growth crystallization...

A. E. S. Van Driessche; J. M. García-Ruíz; K. Tsukamoto; L. D. Patiño-Lopez; H. Satoh

2011-01-01T23:59:59.000Z

13

Glass Fibre Reinforced Cement and Gypsum Products  

Science Journals Connector (OSTI)

6 October 1970 research-article Glass Fibre Reinforced Cement and Gypsum Products A. J. Majumdar Glass fibre reinforced cements and gypsum plaster...discontinuous and irregular. The dispersion of glass fibre in the matrix is not easy. When chopped...

1970-01-01T23:59:59.000Z

14

A final report for Gallium arsenide P-I-N detectors for high-sensitivity imaging of thermal neutrons  

E-Print Network (OSTI)

This SBIR Phase I developed neutron detectors made FR-om gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the FR-ont surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed FR-om a layer of Al sub x Ga sub 1 sub - sub x As. Schottky-barrier diodes formed FR-om the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The lowest dark current measured is 1 x 10 sup - sup 1 sup 2 amps at -1 V o...

Vernon, S M

1999-01-01T23:59:59.000Z

15

Optoelectronic simulation of GaAs solar cells with angularly selective filters  

SciTech Connect

We discuss the influence of angularly selective filters on thin film gallium arsenide solar cells. For this reason, the detailed balance model was refined to fit our needs with respect to Auger recombination, reflection, transmission, and realistic absorption. For calculating real systems, an approach was made to include optical effects of angularly selective filters into electron-hole dynamic equations implemented in PC1D, a one dimensional solar cell calculation tool. With this approach, we find a relative V{sub oc} increase of 5% for an idealized 100?nm GaAs cell, including Auger recombination.

Kraus, Tobias, E-mail: tobias.kraus@ise.fraunhofer.de; Höhn, Oliver; Hauser, Hubert; Bläsi, Benedikt [Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany)

2014-02-07T23:59:59.000Z

16

Gypsum, Colorado: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

Gypsum, Colorado: Energy Resources Gypsum, Colorado: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 39.6469295°, -106.9517109° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":39.6469295,"lon":-106.9517109,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

17

Self-aligned submicron gate length gallium arsenide MESFET  

E-Print Network (OSTI)

SELF-ALIGNED SUBMICRON GATE LENGTH GALLIUM ARSENIDE MESFET A Thesis by HSIEN-CHING HUANG Submitted to the Graduate College of Texas ASSAM University in partial fulfillment of the requirement for the degree ol' MASTER OF SCIENCE May 1987... Major Subject: Electrical Engineering SELF-ALIGNED SUBMICRON GATE LENGTH GALLIUM ARSENIDE MESFET A Thesis by HSIEN-CHING HUANG Approved as to style and content by: Mark. H. Weichold (Chairman of Committee) Donald L. Parker (Member) dali L...

Huang, Hsien-Ching

2012-06-07T23:59:59.000Z

18

Use of waste gypsum to replace natural gypsum as set retarders in portland cement  

SciTech Connect

The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5 wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.

Chandara, Chea; Azizli, Khairun Azizi Mohd [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Ahmad, Zainal Arifin [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)], E-mail: zainal@eng.usm.my; Sakai, Etsuo [Tokyo Institute of Technology, Graduate School of Science and Engineering, Department of Metallurgy and Ceramic Science, 2-12-1 Meguro-ku, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan)

2009-05-15T23:59:59.000Z

19

Process for forming pure silver ohmic contacts to N- and P-type gallium arsenide materials  

DOE Patents (OSTI)

Disclosed is an improved process for manufacturing gallium arsenide semiconductor devices having as its components a n-type gallium arsenide substrate layer and a p-type gallium arsenide diffused layer. The improved process comprises forming a pure silver ohmic contact to both the diffuse layer and the substrate layer wherein the n-type layer comprises a substantially low doping carrier concentration.

Hogan, S.J.

1983-03-13T23:59:59.000Z

20

E-Print Network 3.0 - actively forming gypsum Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

for formation of gypsum) for the reference solution... by ICP-mass spectroscopy analysis for calcium. 4. Results and discussion Gypsum scale can form due... of...

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Properties study of cotton stalk fiber/gypsum composite  

SciTech Connect

This manuscript addresses treating cotton stalk fiber surface with styrene acrylic emulsion, which improves the interfacial combined state of cotton stalk fiber/gypsum composite effectively and improves its mechanical properties notably. Mixes less slag, ordinary Portland cement, etc., to modify gypsum base. The electron microscope was utilized to analyze and research on the effect on composite properties of the abovementioned mixtures.

Li Guozhong; Yu Yanzhen; Zhao Zhongjian; Li Jianquan; Li Changchun

2003-01-01T23:59:59.000Z

22

Occurrence of gypsum in Gulf coast salt domes  

Science Journals Connector (OSTI)

...Occurrence of gypsum in Gulf coast salt domes Barton Donald Clinton...OF GYPSUM IN THE GULF COAST SALT DOMES. Sir: On accountof thepaucityof...concerningtheoccurrenceof gypsumandanhydriteon the salt domes. The followingremarksmay...5o-footsill of saltat 3,350feetat Palangana,possiblyalsoStrattonRidge...

Donald Clinton Barton

23

Flue gas desulfurization gypsum and fly ash  

SciTech Connect

The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority`s newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned for all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective.

Not Available

1992-05-01T23:59:59.000Z

24

E-Print Network 3.0 - americium arsenides Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Summary: of gallium arsenide, a semiconductor, which is used in advanced optoelectronics, lasers, microwave circuits... , and solar cells. To determine material...

25

E-Print Network 3.0 - arsenide- gallium instrument Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Summary: of gallium arsenide, a semiconductor, which is used in advanced optoelectronics, lasers, microwave circuits... , and solar cells. To determine material...

26

E-Print Network 3.0 - aluminium arsenide solar cells Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

manufacturing technique holds Summary: arsenide chips manufactured in multilayer stacks: light sensors, high-speed transistors and solar cells... the photovoltaic cells that solar...

27

E-Print Network 3.0 - arsenide thin films Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Engineering 14 Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy Summary: :jap.aip.orgjap...

28

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production  

SciTech Connect

This report presents and discusses results from Task 5 of the study ''Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,'' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. The FGD process is used to control the sulfur dioxide emissions which would result in acid rain if not controlled. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies developed for power plants involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the synthetic gypsum material is used as a feedstock for wallboard production. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope includes five discrete tasks, each conducted at various USG wallboard plants using synthetic gypsum from different FGD systems. The five tasks were to include (1) a baseline test, then variations representing differing power plant (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5, which was to evaluate gypsum produced from an alternate FGD reagent, could not be conducted as planned. Instead, Task 5 was conducted at conditions similar to a previous task, Task 3, although with gypsum from an alternate FGD system. In this project, process stacks in the wallboard plant have been sampled using the Ontario Hydro method. The stack locations sampled for each task include a dryer for the wet gypsum as it enters the plant and a gypsum calciner. The stack of the dryer for the wet wallboard product was also tested as part of this task, and was tested as part of Tasks 1 and 4. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. The Ontario Hydro results, process sample mercury concentration data, and process data were used to construct mercury mass balances across the wallboard plants. Task 5 was conducted at a wallboard plant processing synthetic gypsum from a power plant that fires Eastern bituminous coal. The power plant is equipped with a selective catalytic reduction (SCR) system for NOX emissions control, but the SCR was bypassed during the time period the gypsum tested was produced. The power plant has a single-loop, open spray tower, limestone reagent FGD system, with forced oxidation conducted in a reaction tank integral with the FGD absorber. The FGD system has gypsum fines blow down as part of the dewatering step. Gypsum fines blow down is believed to be an important variable that impacts the amount of mercury in the gypsum byproduct and possibly its stability during the wallboard process. The results of the Task 5 stack testing, as measured by the Ontario Hydro method, detected that an average of 51% of the incoming mercury in the FGD gypsum was emitted during wallboard production. These losses were distributed as 2% or less each across the wet gypsum dryer and product wallboard dryer, and about 50% across the gypsum calciner. Emissions were similar to what Task 3 results showed, on both a percentage and a mass basis, for gypsum produced by a power plant firing bituminous coal and also having gypsum fines blow down as part of the FGD dewatering scheme. As was seen in the Task 1 through 4 results, most of the mercury detected in the stack testing on the wet gypsum dryer and kettle calciner was in the form of elemental mercury. In the wallboard dryer kiln, a more signific

Jessica Marshall Sanderson

2006-06-01T23:59:59.000Z

29

Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications  

SciTech Connect

The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of {approximately} 10{sup 4} shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 10{sup 8} shots for electro-optic drivers. Much effort is currently being channeled in the study related to improvements of these two parameters high bias operation and lifetime improvement for switches used in pulsed power applications. The contact material and profiles are another important area of study. Although these problems are being pursued through the incorporation of different contact materials and introducing doping near contacts, it is important that the switch properties and the conduction mechanism in these switches be well understood such that the basic nature of the problems can be properly addressed. In this paper the authors report on these two basic issues related to the device operation, i.e., mechanisms for increasing the hold-off characteristics through neutron irradiation, and the analysis of transport processes at varying field conditions in trap dominated SI GaAs in order to identify the breakdown mechanism during device operation. It is expected that this study would result in a better understanding of photoconductive switches, specifically those used in high power operation.

ISLAM,N.E.; SCHAMILOGLU,E.; MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; JOSHI,R.P.

2000-05-30T23:59:59.000Z

30

Novel GaAs Devices  

Science Journals Connector (OSTI)

As the dimensions of GaAs devices shrink, the effective electron velocity should increase, leading to a shorter transit time and to a ballistic or near-ballistic mode of operation (see Chapter 2). At the same ...

Michael Shur

1987-01-01T23:59:59.000Z

31

Characterization of the Interface of Gold and Silver Nanostructures on InP and GaAs Synthesized via Galvanic Displacement  

Science Journals Connector (OSTI)

Galvanic displacement of noble metals on gallium arsenide to produce metal-GaAs junctions has been studied intermittently, starting with a report by Gol’derberg in 1971 of gold on GaAs. ... The presence of an acid is not necessary since Ga2O3 and As2O3 are somewhat water soluble (solubility of As2O3 > Ga2O3),(64, 65) although addition of 2% H2SO4(aq) resulted in greater gold deposition, particularly at the early stages of reaction (the first few minutes). ...

Sayed Y. Sayed; Brian Daly; Jillian M. Buriak

2008-07-23T23:59:59.000Z

32

IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption  

E-Print Network (OSTI)

IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 2, APRIL 2012 123 Gallium Arsenide Solar Cell Absorption flat gallium arsenide solar cell, we show that it is possible to modify the flow of light and enhance above the solar cell. The incoupling element is lossless and, thus, has the advantage that no energy

Grandidier, Jonathan

33

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production  

SciTech Connect

This report presents and discusses results from the project 'Fate of Mercury in Synthetic Gypsum Used for Wallboard Production', performed at five different full-scale commercial wallboard plants. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies involve the capture of mercury in FGD systems. The objective of this study has been to determine whether any mercury is released into the atmosphere at wallboard manufacturing plants when the synthetic gypsum material is used as a feedstock for wallboard production. The project has been co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope included seven discrete tasks, each including a test conducted at various USG wallboard plants using synthetic gypsum from different wet FGD systems. The project was originally composed of five tasks, which were to include (1) a base-case test, then variations representing differing power plant: (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5,could not be conducted as planned and instead was conducted at conditions similar to Task 3. Subsequently an opportunity arose to test gypsum produced from the Task 5 FGD system, but with an additive expected to impact the stability of mercury, so Task 6 was added to the project. Finally, Task 7 was added to evaluate synthetic gypsum produced at a power plant from an additional coal type. In the project, process stacks in the wallboard plant were sampled using the Ontario Hydro method. In every task, the stack locations sampled included a gypsum dryer and a gypsum calciner. In Tasks 1 and 4 through 7, the stack of the dryer for the wet wallboard product was also tested. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. These results and process data were used to construct mercury mass balances across the wallboard plants. The results from the project showed a wide range of percentage mercury losses from the synthetic gypsum feedstocks as measured by the Ontario Hydro method at the process stacks, ranging from 2% to 55% of the mercury in the gypsum feedstock. For the tasks exceeding 10% mercury loss across the wallboard plant, most of the loss occurred across the gypsum calciner. When total wallboard emissions remained below 10%, the primary emission location varied with a much less pronounced difference in emission between the gypsum dryer, calciner and board dryer. For all seven tasks, the majority of the mercury emissions were measured to be in the elemental form (Hg{sup 0}). Overall, the measured mercury loss mass rates ranged from 0.01 to 0.17 grams of mercury per dry ton of synthetic gypsum processed, or 0.01 to 0.4 pounds of mercury released per million square feet of wallboard produced from synthetic gypsum. The Coal Combustion Product Production and Use Survey from the American Coal Ash Association (ACAA) indicate that 7,579,187 short tons of synthetic gypsum were used for wallboard production in 2006. Extrapolating the results of this study to the ACAA industry usage rate, we estimate that mercury releases from wallboard production plants in 2006 ranged between 150 to 3000 pounds for the entire U.S. wallboard industry. With only seven sets of wallboard plant measurements, it is difficult to draw firm conclusions about what variables impact the mercury loss percentages across the wallboard plants. One significant o

Jessica Sanderson

2007-12-31T23:59:59.000Z

34

Biological monitoring of arsenic exposure of gallium arsenide- and inorganic arsenic-exposed workers by determination of inorganic arsenic and its metabolites in urine and hair  

SciTech Connect

In an attempt to establish a method for biological monitoring of inorganic arsenic exposure, the chemical species of arsenic were measured in the urine and hair of gallium arsenide (GaAs) plant and copper smelter workers. Determination of urinary inorganic arsenic concentration proved sensitive enough to monitor the low-level inorganic arsenic exposure of the GaAs plant workers. The urinary inorganic arsenic concentration in the copper smelter workers was far higher than that of a control group and was associated with high urinary concentrations of the inorganic arsenic metabolites, methylarsonic acid (MAA) and dimethylarsinic acid (DMAA). The results established a method for exposure level-dependent biological monitoring of inorganic arsenic exposure. Low-level exposures could be monitored only by determining urinary inorganic arsenic concentration. High-level exposures clearly produced an increased urinary inorganic arsenic concentration, with an increased sum of urinary concentrations of inorganic arsenic and its metabolites (inorganic arsenic + MAA + DMAA). The determination of urinary arsenobetaine proved to determine specifically the seafood-derived arsenic, allowing this arsenic to be distinguished clearly from the arsenic from occupational exposure. Monitoring arsenic exposure by determining the arsenic in the hair appeared to be of value only when used for environmental monitoring of arsenic contamination rather than for biological monitoring.

Yamauchi, H.; Takahashi, K.; Mashiko, M.; Yamamura, Y. (St. Marianna Univ. School of Medicine, Kawasaki (Japan))

1989-11-01T23:59:59.000Z

35

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production  

SciTech Connect

This report presents and discusses results from Task 6 of the study 'Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the synthetic gypsum material is used as a feedstock for wallboard production. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope now includes six discrete tasks, each conducted at various USG wallboard plants using synthetic gypsum from different FGD systems. The project was originally composed of five tasks, which were to include (1) a baseline test, then variations representing differing power plant: (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5, which was to include testing with an alternate FGD reagent, could not be conducted as planned. Instead, Task 5 was conducted at conditions similar to Task 3, although with gypsum from an alternate FGD system. Subsequent to conducting Task 5 under these revised conditions, an opportunity arose to test gypsum produced at the same FGD system, but with an additive (Degussa Corporation's TMT-15) being used in the FGD system. TMT-15 was expected to impact the stability of mercury in synthetic gypsum used to produce wallboard, so Task 6 was added to the project to test this theory. In this project, process stacks in the wallboard plant have been sampled using the Ontario Hydro method. For every task, the stack locations sampled have included a dryer for the wet gypsum as it enters the plant and a gypsum calciner. For Tasks 1, 4, 5 and 6, the stack of the dryer for the wet wallboard product was also tested. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. The Ontario Hydro results, process sample mercury concentration data, and process data were used to construct mercury mass balances across the wallboard plants. Task 6 was conducted at a wallboard plant processing synthetic gypsum from a power plant that fires Eastern bituminous coal. The power plant has a single-loop, open spray tower limestone forced oxidation FGD system, with the forced oxidation conducted in the reaction tank integral with the FGD absorber. The FGD system has gypsum fines blow down as part of the dewatering step. The power plant is equipped with a selective catalytic reduction (SCR) system for NOX emissions control, and the SCR was in service during the time period the gypsum tested was produced. Also, as mentioned above, Degussa additive TMT-15 was being added to the FGD system when this gypsum was produced. The results of the Task 6 stack testing, as measured by the Ontario Hydro method, detected that an average of 55% of the incoming mercury was emitted during wallboard production. These losses were distributed as about 4% across the dryer mill, 6% across the board dryer kiln, and 45% across the kettle calciner. Emissions were similar to what Task 5 results showed on a percentage basis, but about 30% lower on a mass basis. The same power plant FGD system produced the synthetic gypsum used in Task 5 (with no use of TMT-15) and in Task 6 (with TMT-15 added to the FGD system). The lower emissions on a mass basis appeared

Jessica Sanderson; Gary M. Blythe; Mandi Richardson

2006-12-01T23:59:59.000Z

36

Radioactivity in Products Derived from Gypsum in Tanzania  

Science Journals Connector (OSTI)

......Dosimetry Article Radioactivity in Products Derived from Gypsum in Tanzania P. Msaki F.P. Banzi Scientific investigations have long...products suspected to have natural radioactivity radiation risk in Tanzania. In response to the concern expressed by the users of chalk......

P. Msaki; F.P. Banzi

2000-10-01T23:59:59.000Z

37

Gamma doses from phospho-gypsum plaster-board  

SciTech Connect

The use of phospho-gypsum plaster-board and plaster cement in buildings as a substitute for natural gypsum may constitute an additional source of radiation exposure to both workers and members of the public, both from inhalation of radon progeny produced from radon which is exhaled from the plaster-board and from beta and gamma radiation produced by radioactive decay in the plaster-board. The calculations presented in this paper indicate that if phospho-gypsum sheets 1 cm thick containing a {sup 226}Ra concentration of 400 Bq kg{sup -1} are used to line the walls and ceiling of a room of dimensions up to 5 m {times} 5 m {times} 3 m, the annual effective dose from gamma radiation for a person continually occupying the room should not exceed approximately 0.13 mSv. This compares with a measured annual average effective dose from gamma radiation in Australian homes of 0.9 mSv. The annual effective dose from such thin sheets is directly proportional to the {sup 226}Ra concentration in the plaster-board. 13 refs., 6 figs.

O`Brien, R.S. [Australian Radiation Lab., Victoria (Australia)

1997-01-01T23:59:59.000Z

38

All-optical Wavelength Conversion in Aluminum Gallium Arsenide at Telecommunications Wavelengths.  

E-Print Network (OSTI)

??This thesis aims at both developing highly nonlinear Aluminum Gallium Arsenide waveguides(AlGaAs) and demonstrating all-optical wavelength conversion via cross-phase modulation in AlGaAs waveguides at telecommunications… (more)

Ng, Wing-Chau

2011-01-01T23:59:59.000Z

39

Fabrication of optoelectronic microwave linear and ring resonators on a gallium arsenide substrate  

E-Print Network (OSTI)

FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Electrical Engineering FABRICATION OF OPTOELECTRONIC MICROWAVE LINEAR AND RING RESONATORS ON A GALLIUM ARSENIDE SUBSTRATE A Thesis by CHUN-LIANG YEH Approved as to style and content by: Mark...

Yeh, Chun-Liang

1993-01-01T23:59:59.000Z

40

First principles predictions of intrinsic defects in aluminum arsenide, AlAs : numerical supplement.  

SciTech Connect

This Report presents numerical tables summarizing properties of intrinsic defects in aluminum arsenide, AlAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz, 'First principles predictions of intrinsic defects in Aluminum Arsenide, AlAs', Materials Research Society Symposia Proceedings 1370 (2011; SAND2011-2436C), and intended for use as reference tables for a defect physics package in device models.

Schultz, Peter Andrew

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Electrodeposition of Crystalline GaAs on Liquid Gallium Electrodes in Aqueous Electrolytes  

Science Journals Connector (OSTI)

Crystalline gallium arsenide (c-GaAs) possesses many desirable optoelectronic properties suited for solar energy conversion,(1) light and radiation detection,(2) chemical sensing,(3) lighting,(4) and high speed electronics. ... In contrast to conflicting previous reports on the electrodeposition of GaAs,(17, 18) we posit that c-GaAs(s) can be synthesized predictably through the electrodeposition of As from dissolved As2O3 specifically on a Ga(l) electrode at modest temperatures in water. ... Specifically, for any binary system composed of a solid dissolving into a liquid, the rate of dissolution of the solid into the liquid phase is given by eq 5:(60)(5)where kdiss is the dissolution rate constant, s is the surface area of the solid in contact with the liquid, V is the volume of the liquid, Csat is the solubility of the solid in the liquid, and Cdiss is the concentration of the dissolved solid in the bulk of the liquid phase. ...

Eli Fahrenkrug; Junsi Gu; Stephen Maldonado

2012-12-24T23:59:59.000Z

42

Two-photon photovoltaic effect in gallium arsenide Jeff Chiles,1  

E-Print Network (OSTI)

Two-photon photovoltaic effect in gallium arsenide Jichi Ma,1 Jeff Chiles,1 Yagya D. Sharma,2 214669); published September 4, 2014 The two-photon photovoltaic effect is demonstrated in gallium; (230.0250) Optoelectronics; (040.5350) Photovoltaic; (130.4310) Nonlinear. http://dx.doi.org/10.1364/OL

Fathpour, Sasan

43

Analysis of cubic and orthorhombic C3A hydration in presence of gypsum and lime  

E-Print Network (OSTI)

14 days (b). Key: E = ettringite; G = gypsum; C c = cubic CA Fig. 3 SEM pictures of ettringite formation from a cubic Ccubic phase, forming longer ettringite needles; however, the

Kirchheim, A. P.; Fernàndez-Altable, V.; Monteiro, P. J.; Dal Molin, D. C.; Casanova, I.

2009-01-01T23:59:59.000Z

44

NETL: Environmental Research - Fate of Mercury in Synthetic Gypsum Used for  

NLE Websites -- All DOE Office Websites (Extended Search)

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production Fate of Mercury in Synthetic Gypsum Used for Wallboard Production This project will provide information about the fate of mercury in synthetic gypsum produced by wet FGD systems on coal-fired power plants, when used as feedstock for wallboard production. Wet FGD systems play a key role in current and future efforts to limit the air emissions of mercury control from coal-fired plants. Potential emissions of mercury from FGD byproduct gypsum during wallboard production could limit overall mercury control levels achieved by the coal power industry. Furthermore, any adverse effects of elevated mercury levels in wallboard products could undermine the use of FGD gypsum as a feedstock for wallboard plants. Under a Cooperative Agreement with DOE-NETL, USG Corp., a major producer of wallboard, will provide high-quality data on the extent and location of mercury release during the wallboard production process, and provide additional information on the potential for mercury leaching at the end of the wallboard life cycle, when it is disposed in municipal landfills.

45

First-Principles Determination of Ultrahigh Thermal Conductivity of Boron Arsenide: A Competitor for Diamond?  

Science Journals Connector (OSTI)

We have calculated the thermal conductivities (?) of cubic III-V boron compounds using a predictive first principles approach. Boron arsenide is found to have a remarkable room temperature ? over 2000??W?m-1?K-1; this is comparable to those in diamond and graphite, which are the highest bulk values known. We trace this behavior in boron arsenide to an interplay of certain basic vibrational properties that lie outside of the conventional guidelines in searching for high ? materials, and to relatively weak phonon-isotope scattering. We also find that cubic boron nitride and boron antimonide will have high ? with isotopic purification. This work provides new insight into the nature of thermal transport at a quantitative level and predicts a new ultrahigh ? material of potential interest for passive cooling applications.

L. Lindsay; D. A. Broido; T. L. Reinecke

2013-07-08T23:59:59.000Z

46

Estimates of inhalation doses resulting from the possible use of phospho-gypsum plaster-board in Australian homes  

SciTech Connect

Current materials used as internal lining in Australian buildings ade based on natural gypsum of low radium content. A study was carried out to estimate the contribution to the annual effective dose due to airborne contamination from chemical by-product gypsum plaster board of higher radium content if it were used as an internal lining.

O`Brien, R.S.; Peggie, J.R.; Leith, I.S. [Australian Radiation Laboratory, Victoria (Australia)

1995-04-01T23:59:59.000Z

47

J Sci Food Agric 1991, 57, 527-541 Dissolution of Various Sources of Gypsum in Aqueous  

E-Print Network (OSTI)

of flue gas using limestone in coal-fired power stations (Byme 1983). It is anticipated that large amounts of the century, unless there is a major change in power generation policy. Use on agricultural land as a soil grade (AR), three sources of Jlue-gas desulphurisation (FGD) gypsum, phosphogypsum (PG),and mined gypsum

Ahmad, Sajjad

48

Gallium arsenide thermal conductivity and optical phonon relaxation times from first-principles calculations  

E-Print Network (OSTI)

In this paper, thermal conductivity of crystalline GaAs is calculated using first-principles lattice dynamics. The harmonic and cubic force constants are obtained by fitting them to the force-displacement data from density ...

Luo, Tengfei

49

E-Print Network 3.0 - aluminium incorporating al-hf Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Solar Cells May See Off Silicon Summary: which involves growing alternate layers of gallium arsenide (GaAs) and aluminium arsenide (Al... be incorporated into. "If you can...

50

Manufacture of ammonium sulfate fertilizer from FGD-gypsum. Technical report, March 1--May 31, 1995  

SciTech Connect

Goal is to assess technical and economic feasibility for producing fertilizer-grade ammonium sulfate from gypsum produced in limestone flue gas desulfurization (FGD). This is the 1st year of a 2-year program among Illinois State Geological Survey, University of Illinois (Urbana-Champaign), Allied-Signal, Marketing Chem. Process Inc., Henry Fertilizer, Illinois Power Co., and Central Illinois Public Services. In previous quarter, chemistry and process conditions were reviewed and a reactor system set up and used to conduct laboratory tests. FGD-gypsum from Abbott power plant was used. The scrubber, a Chiyoda Thoroughbred 121 FGD, produced a filter cake (98.36% gypsum and < 0.01% CaSO{sub 3}). Conversion of FGD- gypsum to ammonium sulfate was tested at 60-70{degree}C for 5-6 hr. Yield up to 82% and purity up to 95% were achieved for the ammonium sulfate production. During this quarter, more bench-scale experiments including a mass balance analysis were conducted; a yield up to 83% and up to 99% purity were achieved. A literature survey was completed and a preliminary process flow sheet was developed. Economics of the process is being estimated.

Chou, M.I.M.; Rostam-Abadi, Ml; Lytle, J.M.; Bruinius, J.A.; Li, Y.C. [Illinois State Geological Survey, Urbana, IL (United States); Hoeft, R. [Illinois Univ., Urbana, IL (United States); Dewey, S. [AlliedSignal-Chemicals (United States); Achorn, F. [Southeast Marketing Chem. Process INc. (SE-ME) (United States)

1995-12-31T23:59:59.000Z

51

Surface Science Analysis of GaAs Photocathodes Following Sustained...  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, strained super-lattice GaAs photocathode samples, removed from the CEBAF...

52

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride by metalorganic vapor-phase epitaxy  

E-Print Network (OSTI)

Formation of etch pits during carbon doping of gallium arsenide with carbon tetrachloride to examine the effects of carbon tetrachloride concentration and temperature on the morphology of carbon with increasing carbon tetrachloride concentration. Step bunching and pinning was observed at a IV/III ratio

Li, Lian

53

Direct formation of the ?-CaSO4 phase in dehydration process of gypsum: In situ FTIR study  

Science Journals Connector (OSTI)

...occurrence of bassanite in nature is very rare (Yamamoto and Kennedy 1969). Tiemann...into anhydrite at depth. However, the rare occurrence of bassanite in such cases...Dehydration behaviour of natural gypsum and a phosphogypsum during milling. Thermochimica Acta...

P.S.R. Prasad; V. Krishna Chaitanya; K. Shiva Prasad; D. Narayana Rao

54

Implantation of carbon in GaAs  

SciTech Connect

Carbon implanted into GaAs and thermally annealed typically exhibits very low (<3%) electrical activity. It has been demonstrated that the electrical activity of C can be significantly enhanced by co-implantation with Ga. Improved activation may result from either additional damage of the crystal lattice or from stoichiometric changes, forcing the C atoms onto As sites. To determine the relative importance of each of these effects, I have undertaken a systematic study of carbon activation in GaAs. A range of co-implants have been used: group III (B, Ga), group V (N, P, As) and noble gases (Ar, Kr). The damage introduced to the substrate will depend on the mass of the ion implanted. The group III and group V co-implants will affect the crystal stoichiometry. The results indicate that both lattice damage and crystal stoichiometry are important for high electrical activity of C. Increasing the damage will increase the activation due to the increased number of As vacancies but maximum activation can be obtained only by a co-implant which not only damages the lattice but also forces the C to occupy an As site.

Moll, A.J.

1992-03-01T23:59:59.000Z

55

Photocurrent Spectroscopy of Single Wurtzite GaAs Nanowires  

SciTech Connect

Photocurrent of single wurtzite GaAs nanowires grown by Au-assisted molecular beam epitaxy is measured at room and low temperature (10 K). At room temperature a high photo-response with more than two orders of magnitude increase of current is observed. The wavelength dependence of the photocurrent shows a sharp change near the zinc blende GaAs band gap. The absence of the free exciton peak in the low temperature photocurrent spectrum, and problems related to determining the exact position of the energy bandgap of wurtzite GaAs from the observed data are discussed.

Kim, D. C.; Ahtapodov, L.; Boe, A. B.; Moses, A. F.; Dheeraj, D. L.; Fimland, B. O.; Weman, H. [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Choi, J. W.; Ji, H.; Kim, G. T. [School of Electrical Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

2011-12-23T23:59:59.000Z

56

Localized corrosion of GaAs surfaces and formation of porous GaAs  

SciTech Connect

The present work deals with pitting corrosion of p- and n-type GaAs (100). Pit growth can be electrochemically initiated on both conduction types in chloride-containing solutions and leads after extended periods of time to the formation of a porous GaAs structure. In the case of p-type material, localized corrosion is only observed if a passivating film is present on the surface, otherwise -- e.g. in acidic solutions -- the material suffers from a uniform attack (electropolishing) which is independent of the anion present. In contrast, pitting corrosion of n-type material can be triggered independent of the presence of an oxide film. This is explained in terms of the different current limiting factor for the differently doped materials (oxide film in the case of the p- and a space charge layer in the case of the n-GaAs). The porous structure was characterized by SEM, EDX and AES, and consists mainly of GaAs. From scratch experiments it is clear that the pit initiation process is strongly influenced by surface defects. For n-type material, AFM investigations show that light induced roughening of the order of several hundred nm occurs under non-passivating conditions. This nm- scale roughening however does not affect the pitting process.

Schmuki, P.; Vitus, C.M.; Isaacs, H.S. [Brookhaven National Lab., Upton, NY (United States); Fraser, J.; Graham, M.J. [National Research Council of Canada, Ottawa, ON (Canada). Inst. for Microstructural Sciences

1995-12-01T23:59:59.000Z

57

Solvent-Dependent Assembly of Terphenyl- and Quaterphenyldithiol on Gold and Gallium Arsenide  

Science Journals Connector (OSTI)

Solvent-Dependent Assembly of Terphenyl- and Quaterphenyldithiol on Gold and Gallium Arsenide ... This solvent pair was chosen because of an apparent solubility conflict:? while EtOH is the most common solvent for assembling alkylthiol and conjugated monothiol molecules,43-45 the longer n-phenyldithiols (n = 3, 4), in their thioacetyl forms (compounds 3 and 4 in Scheme 1), are poorly soluble in EtOH. ... The precipitate was filtered, washed with water, hexane, and methylene chloride, and dried overnight at 40 °C under vacuum to afford a light-yellow solid (5.90 g, 92%). 1H NMR (200 MHz, CDCl3) ? 7.65 (s, 4H), 7.55 (d, J = 8.0 Hz, 4H), 7.32 (d, J = 8.0 Hz, 4H), 2.55 (s, 6H). ...

Dmitry A. Krapchetov; Hong Ma; Alex K. Y. Jen; Daniel A. Fischer; Yueh-Lin Loo

2005-05-17T23:59:59.000Z

58

GaAs solar cells close to the thermodynamic limit  

Science Journals Connector (OSTI)

The efficiency of GaAs solar cells can be increased by applying angularly selective filters. It is shown in terms of detailed balance model, why this happens and the concept is proven...

Hoehn, Oliver; Kraus, Tobias; Bauhuis, Gerard; Schwarz, Ulrich T; Bläsi, Benedikt

59

Exciton front propagation in photoexcited GaAs quantum wells  

E-Print Network (OSTI)

We report on the study of spatiotemporal self-organization of carriers in photoexcited GaAs quantum wells. Propagating interfaces between electron-rich and hole-rich regions are seen as expanding and collapsing exciton ...

Yang, Sen

60

Hydrogen passivation of EL2 defects and H2*-like complex formation in gallium arsenide  

Science Journals Connector (OSTI)

A complex formed by one As antisite (AsGa), one As, and two H atoms is proposed, in GaAs, which is reminiscent of the H2* defect in crystalline Si and properly accounts for the hydrogen neutralization of the EL2 deep donor activity. It is noticeably stable, in agreement with experimental results. The geometry and electronic structure of this complex present interesting connections with those of the isolated As antisite which clarify the EL2 passivation mechanism.

A. Amore Bonapasta

1995-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Potential Agricultural Uses of Flue Gas Desulfurization Gypsum in the Northern Great Plains  

SciTech Connect

Flue gas desulfurization gypsum (FGDG) is a byproduct from the combustion of coal for electrical energy production. Currently, FGDG is being produced by 15 electrical generating stations in Alabama, Florida, Indiana, Iowa, Kentucky, Ohio, North Carolina, South Carolina, Tennessee, Texas, and Wisconsin. Much of this byproduct is used in the manufacturing of wallboard. The National Network for Use of FGDG in Agriculture was initiated to explore alternative uses of this byproduct. In the northern Great Plains (North Dakota, South Dakota, and Montana), FGDG has the potential to be used as a Ca or S fertilizer, as an acid soil ameliorant, and for reclaiming or mitigating sodium-affected soils. Greater than 1.4 million Mg of FGDG could initially be used in these states for these purposes. Flue gas desulfurization gypsum can be an agriculturally important resource for helping to increase the usefulness of problem soils and to increase crop and rangeland production. Conducting beneficial use audits would increase the public awareness of this product and help identify to coal combustion electrical generating stations the agriculturally beneficial outlets for this byproduct.

DeSutter, T.M.; Cihacek, L.J. [North Dakota State University, Fargo, ND (United States). Department of Soil Science

2009-07-15T23:59:59.000Z

62

Organometallic vapor-phase homoepitaxy of gallium arsenide assisted by a downstream hydrogen afterglow plasma in the growth region  

E-Print Network (OSTI)

of the trimeth- ylgallium (TMGa) for homoepitaxial GaAs. They found in direct comparison of the pure thermal-insulating) substrate is loaded into the depo- sition reactor of Fig. 1 without any chemical degreasing or polishing

Collins, George J.

63

E-Print Network 3.0 - annealed gaas spectroscopic Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

regular arrays of submicron GaAs dots on a silicon... . Annealing in arsine converted the gallium to GaAs, and caused the dots to develop faceted features... by an anneal in...

64

Nickel-cobalt-iron-copper sulfides and arsenides in solution-collapse breccia pipes, northwestern Arizona  

SciTech Connect

An extensive suite of Ni-Co-Fe-Cu sulfides and arsenides lies within the matrix of solution-collapse breccias buried deep within the plateaus of the Grand Canyon region. Ceilings over large caverns in the Redwall collapsed, brecciating the overlying sandstone and forming cylindrical breccia pipes up to 300 ft in diameter that extend vertically as much as 3,000 ft. These highly permeable breccias served as a host for the precipitation of a suite of over 100 minerals, including uraninite, sphalerite, galena and various copper phases, in addition to the Ni-Co-bearing-phase discussed here. Intricately zoned crystals of small (<1 mm), euhedral Ni-Co-Fe-As-S minerals were the first to form during the second major episode of mineralization in these pipes. Several of these phases replace minerals, such as barite and anhydrite, from the first episode. Extensive microprobe work has been done on samples from two breccia pipe mines, the Hack 2 and Orphan, which are about 50 miles apart. Mineral compositions are similar except that no copper is found in the Ni-Co-Fe phases from the Hack 2 mine, while pyrites containing 1 wt % Cu are common from the Orphan, which was mined for copper. In some of these pyrites', Cu is dominant and the mineral is actually villamaninite. Pyrites from both mines characteristically contain 0.5 to 3 wt % As. Metal contents in zones pyrite-bravoite-vaesite (M[sub 1]S[sub 2]) crystals at the Hack 2 mine range from Fe[sub 1] to Fe[sub .12], Ni[sub 0] to Ni[sub .86], and Co[sub 0] to Co[sub .10]. The metal content for polydymite-siegenite-violarite averages about (Ni[sub 2.33]Co[sub .39]Fe[sub .23])(S[sub 3.9]As[sub .1]). Orphan mine pyrite-bravoite-vaesite-villamaninite ranges in composition from pure FeS[sub 2] to (Ni[sub .6]Fe[sub .21]Co[sub .17])S[sub 2], and (Cu[sub .46]Ni[sub .27]Fe[sub .21]Co[sub .13])S[sub 2]. Of all the sulfides or arsenides found in these breccia pipes, only nickeline consistently occurs as the pure end member.

Wenrich, K.J. (Geological Survey, Denver, CO (United States)); Hlava, P.F. (Sandia National Labs., Albuquerque, NM (United States))

1993-04-01T23:59:59.000Z

65

Heat treatment of bulk gallium arsenide using a phosphosilicate glass cap  

SciTech Connect

n-type bulk GaAs crystals, capped with chemically vapor-deposited phosphosilicate glass, were heat treated at temperatures in the range of 600 to 950 /sup 0/C. Measurements on Schottky diodes and solar cells fabricated on the heat-treated material, after removal of a damaged surface layer, show an increase in free-carrier concentration, in minority-carrier-diffusion length, and in solar-cell short-circuit current. The observed changes are attributed to a removal of lifetime-reducing acceptorlike impurities, defects, or their complexes.

Mathur, G.; Wheaton, M.L.; Borrego, J.M.; Ghandhi, S.K.

1985-05-15T23:59:59.000Z

66

Endolithic cyanobacteria in soil gypsum: Occurrences in Atacama (Chile), Mojave (United States), and Al-Jafr Basin (Jordan) Deserts  

E-Print Network (OSTI)

), and Al-Jafr Basin (Jordan) Deserts Hailiang Dong,1 Jason A. Rech,1 Hongchen Jiang,1 Henry Sun,2, United States, and Al-Jafr Basin, Jordan, revealed endolithic cyanobacteria communities just below the Atacama and Mojave Desert, but insignificant in the fibrous gypsum from the Jordan Desert. Endolithic life

Ahmad, Sajjad

67

Operating experience with a GaAs photoemission electron source  

SciTech Connect

We report on the development of several operating procedures that promise to make GaAs photoemission electron sources easier to construct, more reliable to operate, and more amenable to use in dynamic vacuum systems. We describe in particular a method for ''ohmically'' heating a <100> crystal of GaAs under vacuum to approximately 600 /sup 0/C. We also discuss our observations of the role of oxygen in the activation of the crystal surface, the use of continuous cesiation, and of the performance of the crystal under varying vacuum conditions.

Tang, F.C.; Lubell, M.S.; Rubin, K.; Vasilakis, A.; Eminyan, M.; Slevin, J.

1986-12-01T23:59:59.000Z

68

Response of GaAs to fast intense laser pulses  

E-Print Network (OSTI)

Motivated by recent experiments, we have performed simulations which show in detail how the electrons and ions in GaAs respond to fast intense laser pulses (with durations of order 100 fs and intensities of order 1-10 TW/cm(2)). The method of tight...

Graves, JS; Allen, Roland E.

1998-01-01T23:59:59.000Z

69

High-quality InP on GaAs  

E-Print Network (OSTI)

In addition to traditional telecommunication applications, devices based on InP have received increased attention for high-performance electronics. InP growth on GaAs is motivated by the fact that InP wafers are smaller, ...

Quitoriano, Nathaniel Joseph

2006-01-01T23:59:59.000Z

70

The Hall mobility measurement of Liquid Phase Epitaxy grown aluminum gallium arsenide  

E-Print Network (OSTI)

allows lasing action at or above room temperature. The utility of AI?Ga& ?As is based on the close latti&e match to GaAs over a range of Al mole fraction between zero and one(Fig. 1)IS). This is significant since heterojunctions between s...-type by occupying the site normally orc?pi& d by th& gro?p V element, ar?l acting as a donor. For the p-type of AI?Ga& ?As. %1g was used as an i&np?ri&y. Fig. 10 and Fig. 11 show I he r&'lal ionship bet wc?n th& in&p?r&I& & o???& r?t ?&n??&l t he alorr&i& weight...

Choi, Young-Shig

2012-06-07T23:59:59.000Z

71

Wet Chemical Functionalization of III–V Semiconductor Surfaces: Alkylation of Gallium Arsenide and Gallium Nitride by a Grignard Reaction Sequence  

Science Journals Connector (OSTI)

Wet Chemical Functionalization of III–V Semiconductor Surfaces: Alkylation of Gallium Arsenide and Gallium Nitride by a Grignard Reaction Sequence ... These observations are consistent with the known solubility of oxidized As species in water. ... Remote H plasma exposure was effective for removing halogens and hydrocarbons from the surfaces of both nitrides at 450 °C, but was not efficient for oxide removal. ...

Sabrina L. Peczonczyk; Jhindan Mukherjee; Azhar I. Carim; Stephen Maldonado

2012-02-28T23:59:59.000Z

72

The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H. Qi, and R. F. Hicksa)  

E-Print Network (OSTI)

The reaction of carbon tetrachloride with gallium arsenide ,,001... L. Li., S, Gan, B.-K. Han, H, California 90095 Received 26 June 1997; accepted for publication 30 December 1997 Carbon tetrachloride of steps during the vapor-phase epitaxial growth of III­V compound semiconductors.3,4 Carbon tetrachloride

Li, Lian

73

Monolithic integration of GaAs and h~~~~Ga~.~Aslasers by molecular epitaxy on GaAs  

E-Print Network (OSTI)

where the thick cladding layer below the active laser region acts as a buffer layer to-yield comparable epitaxial regrowth of Ino.aGaesAs lasers through dielectric masks between GaAs laser stripes on a GaAs substrate has been used for the -first time- to monolithically integrate these two lasers emitting near 1

74

Recovery and utilization of gypsum and limestone from scrubber sludge. [Quarterly] technical report, March 1, 1993--May 31, 1993  

SciTech Connect

Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}-2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project is investigating methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Work done in the previous quarter concentrated on developing a low-cost froth flotation process that could remove limestone, unburned carbon, and related contaminants from the sludge while recovering the bulk of the calcium sulfite and gypsum. In the current quarter, experiments to remove impurities from the sludge using a water-only cyclone were conducted. The cyclone has been found to be effective for removing the coarser limestone impurities, as well as removing contaminants such as fine gravel and grinding-ball chips. These results show that the cyclone will be very complementary with froth flotation, which mainly removes the very fine impurities.

Kawatra, S.K.; Eisele, T.C. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering

1993-09-01T23:59:59.000Z

75

Recovery and utilization of gypsum and limestone from scrubber sludge. Technical report, December 1, 1992--February 28, 1993  

SciTech Connect

Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}-2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project is investigating methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Work done in the previous quarter concentrated on developing a dependable technique for analysis of scrubber sludge, so that it would be possible to determine exactly how well a particular purification process was working. This technique was then used to characterize the sludge from a particular Illinois power station. In the current quarter, studies were carried out using froth flotation to produce a product that could be oxidized to high-purity gypsum. These experiments have been quite successful, due to certain properties of the limestone impurity that makes it easier to remove by this method than was expected.

Kawatra, S.K.; Eisele, T.C. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Metallurgical and Materials Engineering; Banerjee, D. [Illinois Clean Coal Inst., Carterville, IL (United States)

1993-05-01T23:59:59.000Z

76

A study of the interaction of gallium arsenide with wet chemical formulations using thermodynamic calculations and spectroscopic ellipsometry  

Science Journals Connector (OSTI)

This paper investigates the effectiveness of different wet chemical treatments and their ability to produce/regrow a thin, stable surface oxide layer on GaAs. Results from thermodynamic considerations indicate that a stable surface oxide layer, free of excess arsenic and arsenic oxides, can be achieved by properly choosing aqueous solutions targeted within the GaAs solubility range (pH  11) followed by deionized (DI) water rinsing. This is further corroborated by spectroscopic ellipsometric data that can qualitatively, but correctly, identify the thickness of the surface oxide layer after different wet chemical treatments. Specifically, samples treated with acidic solutions based on HCl, HF, and H3PO4 and diluted ammonium hydroxide solution produce a more stable surface layer that is thinner than the native oxide layer on GaAs. The results and subsequent discussion are presented in the context of an attempt at achieving a well passivated GaAs surface, free of excessive surface state defects responsible for Fermi-level pinning.

J. Price; J. Barnett; S. Raghavan; M. Keswani; R. Govindarajan

2010-01-01T23:59:59.000Z

77

Accurate characterization and improvement of GaAs microstrip attenuation  

E-Print Network (OSTI)

Mason Carroll, B. S. , Rose-Hulman Institute of Technology Chair of Advisory Committee: Dr. Kai Chang Microstrip transmission lines are widely used in microv, ave circuits. The high frequencies cause the microstrip characteristics, especially... OF CONTENTS . . LIST OF FIGURES LIST OF TABLES. . CHAPTER I INTRODUCTION . . I. A Introduction. I. B Thesis Research Il GaAs MICROSTRlp ATTENUATION . II. A Characterization ol'Transmission Line Attenuation. . . . II. A. I Introduction. II. A. 2...

Carroll, James Mason

2012-06-07T23:59:59.000Z

78

An experiment to test the viability of a gallium-arsenide cathode in a SRF electron gun  

SciTech Connect

Strained gallium arsenide cathodes are used in electron guns for the production of polarized electrons. In order to have a sufficient quantum efficiency lifetime of the cathode the vacuum in the gun must be 10{sup -11} Torr or better, so that the cathode is not destroyed by ion back bombardment or through contamination with residual gases. All successful polarized guns are DC guns, because such vacuum levels can not be obtained in normal conducting RF guns. A superconductive RF gun may provide a sufficient vacuum level due to cryo-pumping of the cavity walls. We report on the progress of our experiment to test such a gun with normal GaAs-Cs crystals.

Kewisch,J.; Ben-Zvi, I.; Rao, T.; Burrill, A.; Pate, D.; Wu, Q.; Todd, R.; Wang, E.; Bluem, H.; Holmes, D.; Schultheiss, T.

2009-05-04T23:59:59.000Z

79

Enhanced Performance of Small GaAs Solar Cells via Edge and Surface Passivation with Trioctylphosphine Sulfide  

E-Print Network (OSTI)

Enhanced Performance of Small GaAs Solar Cells via Edge and Surface PassivationAs solar cells. Photoluminescence (PL) measurements indicate monolayers of TOP:S on GaAs significantly" GaAs solar cell (0.31 mm2 ) to test its ability to passivate devices with the relevant dimensions

Atwater, Harry

80

2=picosecond, GaAs photodiode optoelectronic circuit for optical correlation applications  

E-Print Network (OSTI)

2=picosecond, GaAs photodiode optoelectronic circuit for optical correlation applications K. D. Li GaAs Schottky photodiode is monolithically integrated with a microwave detector. By using this new optoelectronic circuit.in place of a nonlinear crystal in an optical correlation setup, the high-speed photodiode

Ozbay, Ekmel

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Electro-optic imagery of high-voltage GaAs photoconductive switches  

SciTech Connect

The authors present electro-optic images of GaAs high-voltage photoconductive switches utilizing the electro-optic effect of the semi-insulating GaAs substrate. Experimental methodology for obtaining the images is described along with a self-calibrating data reduction algorithm. Use of the technique for observing fabrication defects is shown.

Falk, R.A.; Adams, J.C.; Capps, C.D.; Ferrier, S.G.; Krinsky, J.A. (Boeing Defense and Space Group, Seattle, WA (United States))

1995-01-01T23:59:59.000Z

82

ORIGINAL ARTICLE Highly efficient GaAs solar cells by limiting light emission  

E-Print Network (OSTI)

ORIGINAL ARTICLE Highly efficient GaAs solar cells by limiting light emission angle Emily D Kosten1 solar cell under direct sunlight, light is received from the solar disk, but is re-emitted isotropically.1038/lsa.2013.1; published online 4 January 2013 Keywords: detailed balance; GaAs solar cell; light

Atwater, Harry

83

Plasmonic nanoparticle enhanced light absorption in GaAs solar cells Keisuke Nakayama,a  

E-Print Network (OSTI)

Plasmonic nanoparticle enhanced light absorption in GaAs solar cells Keisuke Nakayama,a Katsuaki 22 September 2008 We demonstrate an improvement in efficiency of optically thin GaAs solar cells-ratio nanoparticles effectively increases the optical path of the incident light in the absorber layers resulting

Atwater, Harry

84

Free carrier induced spectral shift for GaAs filled metallic hole arrays  

E-Print Network (OSTI)

. Soref, and J. A. D. Alamo, "Carrier-induced change in refractive index of InP, GaAs, and InGaAsP," IEEE-photon absorption (3PA) assisted by strongly enhanced local fields, reduce the refractive index of GaAs in ~200-nm thick active area through band filling and free carrier absorption. Therefore, the surface plasma wave

New Mexico, University of

85

Calculated spin polarization of field-assisted GaAs electron source  

Science Journals Connector (OSTI)

Calculations are reported showing that for the field-assisted GaAs NEA photocathode, the spin polarization of emitted electrons can be 3.6 times higher than for non-field GaAs sources. The reason for this is that...

B. Yang; V. Guidi; L. Tecchio

1993-02-01T23:59:59.000Z

86

Quantum effects in electron beam pumped GaAs  

SciTech Connect

Propagation of waves in nano-sized GaAs semiconductor induced by electron beam are investigated. A dispersion relation is derived by using quantum hydrodynamics equations including the electrons and holes quantum recoil effects, exchange-correlation potentials, and degenerate pressures. It is found that the propagating modes are instable and strongly depend on the electron beam parameters, as well as the quantum recoil effects and degenerate pressures. The instability region shrinks with the increase of the semiconductor number density. The instability arises because of the energetic electron beam produces electron-hole pairs, which do not keep in phase with the electrostatic potential arising from the pair plasma.

Yahia, M. E. [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt) [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Azzouz, I. M. [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt)] [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)] [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)

2013-08-19T23:59:59.000Z

87

Back contacted and small form factor GAAS solar cell.  

SciTech Connect

We present a newly developed microsystem enabled, back-contacted, shade-free GaAs solar cell. Using microsystem tools, we created sturdy 3 {micro}m thick devices with lateral dimensions of 250 {micro}m, 500 {micro}m, 1 mm, and 2 mm. The fabrication procedure and the results of characterization tests are discussed. The highest efficiency cell had a lateral size of 500 {micro}m and a conversion efficiency of 10%, open circuit voltage of 0.9 V and a current density of 14.9 mA/cm{sup 2} under one-sun illumination.

Clews, Peggy Jane; Wanlass, Mark W. (National Renewable Energy Laboratory); Sanchez, Carlos A.; Pluym, Tammy; Cruz-Campa, Jose Luis; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James

2010-06-01T23:59:59.000Z

88

Exciton front propagation in photoexcited GaAs quantum wells  

Science Journals Connector (OSTI)

We report on the study of spatiotemporal self-organization of carriers in photoexcited GaAs quantum wells. Propagating interfaces between electron-rich and hole-rich regions are seen as expanding and collapsing exciton rings in exciton emission patterns. The interfaces preserve their integrity during expansion, remaining as sharp as in the steady state, which indicates that the dynamics is controlled by carrier transport. The front propagation velocity is measured and compared to theoretical model. The measurements of expanding and collapsing exciton rings afford a contactless method for probing the electron and hole transport.

Sen Yang, L. V. Butov, L. S. Levitov, B. D. Simons, and A. C. Gossard

2010-03-16T23:59:59.000Z

89

Processing Techniques for the 93 K Superconductor Ba2YCu3O7  

Science Journals Connector (OSTI)

...of either silicon or gallium arsenide field effect transistor...BaF2 also require some water to hydrolyze ith fluoride...than the normal solid solubilities. In addition, the...particularly in 930 gallium arsenide (GaAs) circuits...

D. W. MURPHY; D. W. JOHNSON JR.; S. JIN; R. E. HOWARD

1988-08-19T23:59:59.000Z

90

26. 1% solar cell efficiency for Ge mechanically stacked under GaAs  

SciTech Connect

We have processed a diffused Ge wafer into a Ge concentrator solar cell and mechanically stacked it under a GaAs cell fabricated by Varian. We measured this stack's efficiency to be 26.1% for terrestrial air mass 1.5 direct (AM1.5D) conditions at a 285 x concentration ratio. We showed that this efficiency is limited by optical absorption in the Varian GaAs cell caused by high 2--4 (10/sup 18/) cm/sup -3/ substrate doping. We used a 2 x 10/sup 17/ cm/sup -3/ doped GaAs filter to estimate the stack efficiency as 27.4%, which would be achieved with the same Varian GaAs cell formed on a lower doped substrate. We project efficiencies assuming the best properties reported for a GaAs device. This gives a 29.6% efficiency for an improved, planar Ge cell and 31.6% efficiency for a proposed point contact geometry for the Ge cell. The corresponding space (AM0) efficiencies at a 159 x concentration ratio range from the 23.4% value we measured on the stack up to 28.4% projected for the point contact Ge place under the best GaAs cell. We showed that Ge cells give higher efficiencies than Si when stacked under GaAs.

Partain, L.D.; Kuryla, M.S.; Weiss, R.E.; Ransom, R.A.; McLeod, P.S.; Fraas, L.M.; Cape, J.A.

1987-10-01T23:59:59.000Z

91

Isotope (?13C and ?18O) compositions of dolomites from the Permian evaporitic sequences of the Eastern Russian Plate: Evidence from the Syukeevo gypsum deposit  

Science Journals Connector (OSTI)

Carbon and oxygen isotope compositions has been studied in dolomites of the Syukeevo gypsum deposit located in the Eastern Russian Plate. Values of ?13C in the dolomites vary from 0.3 to 6.6 ‰; ?18O, from 28.0 to...

R. Kh. Sungatullin; V. N. Kuleshov; R. I. Kadyrov

2014-09-01T23:59:59.000Z

92

CO{sub 2} laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements  

SciTech Connect

A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10{sup 17} m{sup ?2} in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

Bamford, D. J.; Cummings, E. A.; Panasenko, D. [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States)] [Physical Sciences Inc., 6652 Owens Drive, Pleasanton, California 94588 (United States); Fenner, D. B.; Hensley, J. M. [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States)] [Physical Sciences Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States); Boivin, R. L.; Carlstrom, T. N.; Van Zeeland, M. A. [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)] [General Atomics, P.O. Box 85608, San Diego, California 92186 (United States)

2013-09-15T23:59:59.000Z

93

Efficiency enhancement in GaAs solar cells using self-assembled microspheres  

Science Journals Connector (OSTI)

In this study we develop an efficient light harvesting scheme that can enhance the efficiency of GaAs solar cells using self-assembled microspheres. Based on the scattering of the...

Chang, Te-Hung; Wu, Pei-Hsuan; Chen, Sheng-Hui; Chan, Chia-Hua; Lee, Cheng-Chung; Chen, Chii -Chang; Su, Yan-Kuin

2009-01-01T23:59:59.000Z

94

Fabrication and Electronic Investigation of GaAs nanowire/Graphene Hybrid Devices.  

E-Print Network (OSTI)

?? In the present study, a process for fabricating GaAs nanowire/graphene hybrid devices using electron beam lithography processing techniques is presented and demonstrated. Fabricated devices… (more)

Bang, Ambjørn Dahle

2014-01-01T23:59:59.000Z

95

Ambipolar spin diffusion and D'yakonov-Perel' spin relaxation in GaAs quantum wells  

E-Print Network (OSTI)

We report theoretical and experimental studies of ambipolar spin diffusion in a semiconductor. A circularly polarized laser pulse is used to excite spin-polarized carriers in a GaAs multiple quantum-well sample at 80 K. ...

Zhao, Hui; Mower, Matt; Vignale, G.

2009-03-01T23:59:59.000Z

96

E-Print Network 3.0 - activated gaas surface Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Collection: Materials Science 8 Dissimilar and Nanomaterials for Optoelectronic Devices Summary: ) on GaAs Diluted-N-based QW Sb-based QW (GaInNAsSb) QD-based active...

97

Electron transfer and capture dynamics in ZnSe quantum wells grown on GaAs  

SciTech Connect

We investigate the transfer and capture dynamics of electrons in phase coherent photorefractive ZnSe quantum wells grown on GaAs using degenerate three-beam four-wave-mixing. The measurements reveal electron capture times by the quantum well in the order of several tens of picoseconds and a transit time of approximately 5 picoseconds from the GaAs substrate through the ZnMgSe barrier.

Dongol, A.; Wagner, H. P. [Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221 (United States)

2013-12-04T23:59:59.000Z

98

Further observations on the operation of a GaAs polarized electron source  

SciTech Connect

We report on several important features of GaAs polarized electron source operation. Specifically we point out the beneficial effect on crystal lifetime produced by the constant low-level application of cesium from a dispenser embedded in an extraction anode. Using our experience in low-energy polarized electron-atom scattering as a reference, we also discuss the importance of frequent energy calibrations of GaAs electron beams for high-resolution investigations.

Guo, X.Q.; Crowe, D.M.; Lubell, M.S.; Tang, F.C.; Vasilakis, A. (Department of Physics, The City College of CUNY, New York, New York 10031 (USA)); Eminyan, M. (Laboratoire de Physique Atomique, Tour 24, Universite Paris VII, F-75251 Paris (France)); Slevin, J. (Department of Experimental Physics, St. Patrick's College, Maynooth, County Kildare (Ireland))

1990-07-01T23:59:59.000Z

99

Defect studies in low-temperature-grown GaAs  

SciTech Connect

High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V{sub Ga}. The neutral AsGa-related defects were measured by infrared absorption at 1{mu}m. Gallium vacancies, V{sub Ga}, was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10{sup 19} cm{sup {minus}3} Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As{sub Ga} in the layer. As As{sub Ga} increases, photoquenchable As{sub Ga} decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As{sub Ga} content around 500C, similar to irradiation damaged and plastically deformed Ga{sub As}, as opposed to bulk grown GaAs in which As{sub Ga}-related defects are stable up to 1100C. The lower temperature defect removal is due to V{sub Ga} enhanced diffusion of As{sub Ga} to As precipitates. The supersaturated V{sub GA} and also decreases during annealing. Annealing kinetics for As{sub Ga}-related defects gives 2.0 {plus_minus} 0.3 eV and 1.5 {plus_minus} 0.3 eV migration enthalpies for the As{sub Ga} and V{sub Ga}. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As{sub Ga}-related defects anneal with an activation energy of 1.1 {plus_minus} 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As{sub Ga}-Be{sub Ga} pairs. Si donors can only be partially activated.

Bliss, D.E.

1992-11-01T23:59:59.000Z

100

Defect studies in low-temperature-grown GaAs  

SciTech Connect

High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

Bliss, D.E.

1992-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

GaAs Blocked-Impurity-Band Detectors for Far-Infrared Astronomy  

SciTech Connect

High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 10{sup 13} cm{sup -3}, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing layer of a BIB detector, has been achieved. The control of the donor concentration, however, was found to be insufficient for detector production. The growth by LPE of a high-purity film onto a commercially grown vapor-phase epitaxial (VPE) n-type GaAs doped absorbing layer resulted in a BIB device that showed a significant reduction in the low-temperature dark current compared to the absorbing layer only. Extended optical response was not detected, most likely due to the high compensation of the commercially grown GaAs absorbing layer, which restricts the depletion width of the device.

Cardozo, Benjamin Lewin

2004-12-21T23:59:59.000Z

102

Metal-insulator-semiconductor structures on p-type GaAs with low interface state density  

E-Print Network (OSTI)

Metal-insulator-semiconductor structures on p-type GaAs with low interface state density Zhi Chen properties of in situ deposited Si3N4 /Si/p-GaAs metal-insulator-semiconductor structures have been offered by a low gate leakage technology in GaAs, such as metal insulator structures, func- tional Ga

Chen, Zhi

103

Disilane: A new silicon doping source in metalorganic chemical vapor deposition of GaAs  

Science Journals Connector (OSTI)

Disilane (Si2H6) is presented as a new silicon doping source in the metalorganic chemical vapor deposition of GaAs together with comparison results obtained using the conventional silane (SiH4) doping source. The dopingcharacteristics of disilane were studied over a wide range of growth conditions: temperature gas phase stoichiometry and disilane concentration in the growth ambient. Silicon incorporation by means of disilane pyrolysis showed no temperature dependence in sharp contrast to the strong temperature activated dependence found when employing silane. The decomposition reaction of disilane proved to be very efficient reducing the amount of dopant gas required by about two orders of magnitude at the lower growth temperatures. Electrical measurements on disilane?doped GaAs yield the same high mobilities as obtained in silane?doped GaAs films indicative of low compensation.

T. F. Kuech; B. S. Meyerson; E. Veuhoff

1984-01-01T23:59:59.000Z

104

Second harmonic generation in photonic crystal cavities in (111)-oriented GaAs  

SciTech Connect

We demonstrate second harmonic generation at telecommunications wavelengths in photonic crystal cavities in (111)-oriented GaAs. We fabricate 30 photonic crystal structures in both (111)- and (100)-oriented GaAs and observe an increase in generated second harmonic power in the (111) orientation, with the mean power increased by a factor of 3, although there is a large scatter in the measured values. We discuss possible reasons for this increase, in particular, the reduced two photon absorption for transverse electric modes in (111) orientation, as well as a potential increase due to improved mode overlap.

Buckley, Sonia, E-mail: bucklesm@stanford.edu; Radulaski, Marina; Vu?kovi?, Jelena [E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States)] [E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States); Biermann, Klaus [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)] [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)

2013-11-18T23:59:59.000Z

105

Microscopic identification of the compensation mechanisms in Si-doped GaAs  

Science Journals Connector (OSTI)

The compensation mechanisms of SiGa donors in GaAs are determined by scanning tunneling microscopy. With increasing Si concentration the SiGa donors are consecutively electrically deactivated by SiAs acceptors, Si clusters, and SiGa-Ga-vacancy complexes. A microscopic model based on the screened Coulomb interaction between charged dopants, the amphoteric nature of Si, and the Fermi-level effect is proposed. It explains the observed defects, the critical Si concentrations of each identified mechanism, and predicts the solubility limit of Si in GaAs. © 1996 The American Physical Society.

C. Domke, Ph. Ebert, M. Heinrich, and K. Urban

1996-10-15T23:59:59.000Z

106

Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs  

SciTech Connect

We have studied photoluminescence (PL) from individual isoelectronic traps formed by nitrogen-nitrogen (NN) pairs in GaAs. Sharp emission lines due to exciton and biexciton were observed from individual isoelectronic traps in nitrogen atomic-layer doped (ALD) GaAs. The binding energy of biexciton bound to individual isoelectronic traps was approximately 8 meV. Both the exciton and biexciton luminescence lines show completely random polarization and no fine-structure splitting. These results are desirable to the application to the quantum cryptography used in the field of quantum information technology.

Takamiya, Kengo; Fukushima, Toshiyuki; Yagi, Shuhei; Hijikata, Yasuto; Yaguchi, Hiroyuki [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku , Saitama 338-8570 (Japan); Mochizuki, Toshimitsu; Yoshita, Masahiro; Akiyama, Hidefumi [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Kuboya, Shigeyuki; Onabe, Kentaro [Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Katayama, Ryuji [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2013-12-04T23:59:59.000Z

107

Formation energy of excess arsenic atoms in n-type GaAs  

Science Journals Connector (OSTI)

We report the first determination of the formation energy of excess-As-atom–related defects in Te-doped GaAs. The photocapacitance method in the constant-capacitance condition is applied to GaAs:Te prepared by 67-h annealing at 850–1100 °C under various As vapor pressures followed by rapid cooling. From an Arrhenius plot of the saturating deep-level density at quasi thermal equilibrium under high As vapor pressure, the formation energy of the defect is determined to be 1.16 eV in Te-doped horizontal-Bridgeman-grown GaAs crystals.

Jun-ichi Nishizawa; Yutaka Oyama; Kazushi Dezaki

1990-11-12T23:59:59.000Z

108

Dry, laser?assisted rapid HBr etching of GaAs  

Science Journals Connector (OSTI)

Dry rapid etching of GaAs has been accomplished using an excimer laser (ArF 193 nm) with HBr etching gas by photochemical initiation. Spatially uniform etch rates of up to 8 ?m/min have been achieved on large?area masked substrates. Selective crystallographic etching is observed and controlled in the process.

P. D. Brewer; D. McClure; R. M. Osgood Jr.

1985-01-01T23:59:59.000Z

109

Dynamics of Subsurface and Surface Chemisorption for B, C, and N on Gaas and Inp  

E-Print Network (OSTI)

Using Hellmann-Feynman molecular-dynamics simulations, we have investigated interactions of first-row elements with the (110) surfaces of GaAs and InP. We find that these atoms prefer to occupy subsurface sites. The open structure...

MENON, M.; Allen, Roland E.

1991-01-01T23:59:59.000Z

110

Near perfect solar absorption in ultra-thin-film GaAs photonic crystals  

E-Print Network (OSTI)

Near perfect solar absorption in ultra-thin-film GaAs photonic crystals Sergey Eyderman,*a Alexei Deinegaa and Sajeev Johnab We present designs that enable a significant increase of solar absorption­99.5% solar absorption is demonstrated depending on the photonic crystal architecture used and the nature

John, Sajeev

111

GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies  

E-Print Network (OSTI)

LETTERS GaAs photovoltaics and optoelectronics using releasable multilayer epitaxial assemblies-frequency electronics3,4 and most forms of optoelectronics5,6 . However, growing large, high quality wafers implementation. More tractable, yet still difficult, problems appear in advanced electronics and optoelectronics

Rogers, John A.

112

Orientation of tectonic stresses in central Kentucky during U. Devonian/L. Mississippian times: Evidence from quartz veins (after gypsum) in NE-trending, systematic joints in shales  

SciTech Connect

Quartz replacing fibrous gypsum and anhydrite pseudomorphically (QAS; quartz after sulfate''), and preserving characteristic crack-seal'' and chickenwire'' textures, occurs in extensional veins at four locations in central KY. The veins occupy a systematic set of NE-SW-trending, vertical joints within the essentially flat-lying shales of the Renfro Member of the Mississippian Borden Formation and the Late Devonian New Albany Shale. The four QAS occurrences discovered to date are located northeast of the Borden Front. At one site in the New Albany Shale, QAS veins show clear evidence of penecontemporaneous deformation. It is proposed that at all QAS locations, gypsum precipitated in incipient joints before complete lithification of the sediment, and grew perpendicular to the fractures to form extensional veins in the soft but firm muds. The orientations of the joints now marked by QAS veins are broadly consistent with regional patterns of NE-SW-trending systematic joints and lineaments in southern IN and in central and eastern KY. These systematic fracture patterns do not correspond directly to known basement faults or rift systems, although they are consistent with modern stress directions in eastern and western KY, measured in situ in wells and by earthquake fault-plane solutions. It is proposed that this systematic trend marks the regional tectonic stress pattern characteristic of southern IN and central and eastern KY at, and since the Late Devonian. The evidence of penecontemporaneous sedimentary deformation in joints of U. Devonian age, marked and preserved by quartz replacement of early gypsum, is sufficient to show that while the systematic NE-trending joint set in KY may also be modern it is not uniquely so.

Grover, J.; Dupuis-Nouille, E.M. (Univ. of Cincinnati, Cincinnati, OH (United States). Dept. of Geology)

1992-01-01T23:59:59.000Z

113

InGaN working electrodes with assisted bias generated from GaAs solar cells for efficient water splitting  

Science Journals Connector (OSTI)

Hydrogen generation through water splitting by n-InGaN working electrodes with bias generated from GaAs solar cell was studied. Instead of using an external bias provided by power...

Liu, Shu-Yen; Sheu, J K; Lin, Yu-Chuan; Chen, Yu-Tong; Tu, S J; Lee, M L; Lai, W C

2013-01-01T23:59:59.000Z

114

The effect of a low-energy electron beam and evaporated gold flux on GaAs surface content  

Science Journals Connector (OSTI)

This work studies changes of the GaAs surface state under the effect of low-intensity electron flux and under the effect of weakly ionized plasma (evaporated Au vapors in vacuum). It is shown that the structure a...

T. A. Bryantseva; D. V. Lyubchenko…

2012-01-01T23:59:59.000Z

115

Fabrication of wideband optoelectronic differential amplifier using a balanced receiver on a semi-insulating GaAs substrate  

E-Print Network (OSTI)

FABRICATION OF WIDEBAND OPTOELECTRONIC DIFFERENTIAL AMPLIFIER USING A BALANCED RECEIVER ON A SEMI-INSULATING GAAS SUBSTRATE A Thesis by KYOO NAM CHOI Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE December 1989 Major Subject: Electrical Engineering FABRICATION Ol' WIDEBAND OPTOELECTRONIC DIFFERENTIAL A1VIPLIFIER USING A BAI, ANCED RECEIVER ON A SEMI. INSULATING GAAS SUBSTRATE A Thesis by l(YOO NAM...

Choi, Kyoo Nam

1989-01-01T23:59:59.000Z

116

A near-infrared photoluminescence study of GaAs nanocrystals in SiO2 films formed by sequential ion implantation  

E-Print Network (OSTI)

A near-infrared photoluminescence study of GaAs nanocrystals in SiO2 films formed by sequential ion GaAs nanocrystals are formed in SiO2 films and several PL bands appear in the red and near-infrared spectral region. Defects and impurities in GaAs nanocrystals and SiO2 cause weak luminescence in the near-infrared

Atwater, Harry

117

Growth and properties of crystalline barium oxide on the GaAs(100) substrate  

SciTech Connect

Growing a crystalline oxide film on III-V semiconductor renders possible approaches to improve operation of electronics and optoelectronics heterostructures such as oxide/semiconductor junctions for transistors and window layers for solar cells. We demonstrate the growth of crystalline barium oxide (BaO) on GaAs(100) at low temperatures, even down to room temperature. Photoluminescence (PL) measurements reveal that the amount of interface defects is reduced for BaO/GaAs, compared to Al{sub 2}O{sub 3}/GaAs, suggesting that BaO is a useful buffer layer to passivate the surface of the III-V device material. PL and photoemission data show that the produced junction tolerates the post heating around 600?°C.

Yasir, M.; Dahl, J.; Lång, J.; Tuominen, M.; Punkkinen, M. P. J.; Laukkanen, P., E-mail: pekka.laukkanen@utu.fi; Kokko, K. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)] [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Kuzmin, M. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland) [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Korpijärvi, V.-M.; Polojärvi, V.; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland)] [Optoelectronics Research Centre, Tampere University of Technology, FI-33101 Tampere (Finland)

2013-11-04T23:59:59.000Z

118

Comparison of the (2×2) reconstructions of GaAs{111} surfaces  

Science Journals Connector (OSTI)

The {111} surfaces of GaAs have been examined using scanning tunneling microscopy and soft x-ray photoelectron spectroscopy and a comparison has been made between the three different (2×2) reconstructions observed. We find that both the (111)A and (111)B surfaces initially exhibit (2×2) ordered adstructures following the thermal desorption of an As cap, though spectroscopy shows them to be chemically inequivalent. With increasing temperature, the (111)A surface is found to develop into a Ga-vacancy (2×2) structure, in many ways similar to a (110) surface. The GaAs(111)B surface, however, loses its (2×2) periodicity with increasing annealing temperature, following a sequence of less As-rich structures.

J. M. C. Thornton; P. Weightman; D. A. Woolf; C. J. Dunscombe

1995-05-15T23:59:59.000Z

119

Hot-carrier cooling in GaAs: Quantum wells versus bulk  

Science Journals Connector (OSTI)

Hot-electron cooling dynamics in photoexcited bulk and quantum-well GaAs structures were determined using time-correlated single-photon counting of photoluminescence (PL) decay. Hot-electron cooling curves were generated from analyses of the time-resolved PL spectra. The time constant characterizing the hot-electron energy-loss rate, ?avg, was then determined, taking into account electron degeneracy and the time dependence of the quasi-Fermi-level. This analysis was also applied to earlier data obtained by Pelouch et al. with the same samples, but based on PL up-conversion experiments with carrier density) to bulk GaAs when this density is above a critical value. This critical density was found to range from high 1017 to low 1018 cm-3, depending upon the experimental technique; at the highest carrier densities, values of ?avg for quantum wells were found to be many hundreds of ps.

Y. Rosenwaks; M. C. Hanna; D. H. Levi; D. M. Szmyd; R. K. Ahrenkiel; A. J. Nozik

1993-11-15T23:59:59.000Z

120

(2×2) reconstructions of the {111} polar surfaces of GaAs  

Science Journals Connector (OSTI)

Ab initio total-energy calculations were used to examine (2×2) reconstruction models for the (111) and (1¯1¯1¯) surfaces of GaAs. For the (111) surface the lowest-energy Ga-vacancy geometry is determined; several mechanisms for Ga-vacancy formation are examined and other reconstructions are discussed. For the (1¯1¯1¯) surface it is shown that the As-vacancy model is unlikely and other geometries are considered.

E. Kaxiras; Y. Bar-Yam; J. D. Joannopoulos; K. C. Pandey

1986-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Vacancy-Buckling Model for the (2×2) GaAs(111) Surface  

Science Journals Connector (OSTI)

A vacancy-buckling model is proposed for the (2×2) structure of the GaAs(111) surface. The model is confirmed by analysis of low-energy electron diffraction spectra. A reconstruction mechanism, basic to III-V compound surfaces, is proposed which favors equal numbers of dangling bonds on the nearest Ga and As neighbors. This model explains the (2×2) and (1×1) periodicities observed on (111) and (110) surfaces, respectively.

S. Y. Tong; G. Xu; W. N. Mei

1984-05-07T23:59:59.000Z

122

Molecular Beam Epitaxial Growth of GaAs on (631) Oriented Substrates  

SciTech Connect

In this work, we report the study of the homoepitaxial growth of GaAs on (631) oriented substrates by molecular beam epitaxy (MBE). We observed the spontaneous formation of a high density of large scale features on the surface. The hilly like features are elongated towards the [-5, 9, 3] direction. We show the dependence of these structures with the growth conditions and we present the possibility of to create quantum wires structures on this surface.

Cruz Hernandez, Esteban; Rojas Ramirez, Juan-Salvador; Contreras Hernandez, Rocio; Lopez Lopez, Maximo [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, Mexico D.F., 07000 (Mexico); Pulzara Mora, Alvaro [Universidad Nacional de Colombia - Sede Manizales, A. A. 127 (Colombia); Mendez Garcia, Victor H. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Av. Karakorum 1470, Lomas 4a Seccion, C.P. 78210, San Luis Potosi (Mexico)

2007-02-09T23:59:59.000Z

123

Design and realization of a GaAs FET integrated with a heterojunction photodiode  

E-Print Network (OSTI)

1595 Design and realization of a GaAs FET integrated with a heterojunction photodiode F. Therez, M, accepté le 6 juillet 1987) Résumé. 2014 L'association d'une photodiode à hétérojonction et d'un circuit circuits intégrant l'amplificateur et la photodiode. Les divers dispositifs sont caractérisés et analysés

Paris-Sud XI, Université de

124

IMPLICATIONS OF THE INTERFACE EFFECTS IN THE NORMALLY-OFF TYPE GaAs MESFETs  

E-Print Network (OSTI)

771 IMPLICATIONS OF THE INTERFACE EFFECTS IN THE NORMALLY-OFF TYPE GaAs MESFETs G. BERT and G déserte à l'interface canal-substrat ainsi qu'à la surface de l'espace source-grille. Cette dernière, qui to the Schottky gate space-charge region both a depleted layer at the channel-substrate interface and a depleted

Boyer, Edmond

125

Raman scattering studies of the GaAs native oxide interface  

Science Journals Connector (OSTI)

Oxide filmsgrown by heat treatment on the 100 and 111 faces of GaAs have been studied by Raman backscattering. A spectrum consisting of the bulk LO and TO lines of GaAs and two additional lines labeled R1 and R2 is observed on all samples prepared at temperatures above 435° C. The additional modes are attributed to an interface region of perhaps several hundred angstroms thickness beneath the oxide film. This structure appears to be made unstable by chemical removal of the film. After the film is removed the spectrum is annealed (returns to that of GaAs) in a matter of weeks at room temperature and in about 1 h at 400° C whether the annealing atmosphere is N2 O2 or forming gas. One of the modes R2 appears to scatter as a scalar i.e. a diagonal Raman matrix element. Spectra by the R1 mode on the other hand appear to be largely unpolarized or possibly slightly nondiagonal in character. Some speculations about the possible nature of the interface region are presented.

J. A. Cape; W. E. Tennant; L. G. Hale

1977-01-01T23:59:59.000Z

126

Identification of As-vacancy complexes in Zn-diffused GaAs  

SciTech Connect

We have used positron annihilation spectroscopy to study the introduction of point defects in Zn-diffused semi-insulating GaAs. The diffusion was performed by annealing the samples for 2 h at 950 Degree-Sign C. The samples were etched in steps of 7 {mu}m. Both Doppler broadening using slow positron beam and lifetime spectroscopy studies were performed after each etching step. Both techniques showed the existence of vacancy-type defects in a layer of about 45 {mu}m. Secondary ion mass spectroscopy measurements illustrated the presence of Zn at high level in the sample almost up to the same depth. Vacancy-like defects as well as shallow positron traps were observed by lifetime measurements. We distinguish two kinds of defects: As vacancy belongs to defect complex, bound to most likely one Zn atom incorporated on Ga sublattice, and negative-ion-type positron traps. Zn acceptors explained the observation of shallow traps. The effect of Zn was evidenced by probing GaAs samples annealed under similar conditions but without Zn treatment. A defect-free bulk lifetime value is detected in this sample. Moreover, our positron annihilation spectroscopy measurements demonstrate that Zn diffusion in GaAs system is governed by kick-out mechanism.

Elsayed, M. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Department of Physics, Faculty of Science, Minia University, 61519 Minia (Egypt); Krause-Rehberg, R. [Department of Physics, Martin Luther University Halle, 06099 Halle (Germany); Korff, B. [Bremen Center for Computational Materials Science, University Bremen, 28359 Bremen (Germany); Richter, S. [Fraunhofer Center for Silicon Photovoltaics CSP, 06120 Halle (Saale) (Germany); Leipner, H. S. [Center of Materials Science, Martin Luther University Halle, 06099 Halle (Germany)

2013-03-07T23:59:59.000Z

127

Interface magnetism of iron grown on sulfur and hydrogen passivated GaAs(001)  

SciTech Connect

Sulfur (S) and hydrogen (H) atom passivated GaAs(001) templates were used for deposition of ultrathin crystalline Fe films using molecular beam epitaxy, where the Fe thickness ranged from 10 to 45 atomic layers. Reflection high-energy electron diffraction patterns showed that the S- and H-passivated surfaces had no and very weak (1 x 2) superlattice reconstructions, respectively. This indicates that these GaAs(001) templates have a square-like symmetry. Magnetic anisotropies were investigated using the in-plane angular dependence of ferromagnetic resonance at 36 GHz. The in-plane cubic and uniaxial anisotropies and perpendicular uniaxial field were described by bulk and interface contributions, indicating that the Fe films have a high lattice coherence. The magnetic properties of the Fe films were compared to those grown on more commonly used GaAs(001) templates having a (4 x 6) reconstruction with an As-rich in-plane uniaxial symmetry. The Fe films grown on S-passivated templates exhibited unique magnetic properties caused by a decreased lattice spacing compared to the bulk Fe.

Kardasz, B.; Watkins, S. P.; Montoya, E. A.; Burrowes, C.; Girt, E.; Heinrich, B.

2012-04-01T23:59:59.000Z

128

The Mechanism of Hydrogen Gas Evolution on GaAs Cathodes Elucidated by In Situ Infrared Spectroscopy  

Science Journals Connector (OSTI)

With n-type gallium arsenide, we present the first quantitative and dynamic study of hydrogen adsorption at a solid?liquid interface by in situ infrared spectroscopy in real time. ... The broadness of the signal may be accounted for in terms of interaction between As?H and water (see ref 22 for the analogous case of Si?H) and/or by the existence of distinct As?H sites at the surface. ... 55 One pH-dependent change in surface chemistry could be related to the solubility of oxidized arsenic. ...

B. H. Erné; F. Ozanam; J.-N. Chazalviel

1999-03-27T23:59:59.000Z

129

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

Science Journals Connector (OSTI)

We report the initial results of GaAs and GaInP solar cells grown by all solid-state molecular- ... (MBE) technique. For GaAs single-junction solar cell, with the application of AlInP as ... back surface field la...

Shulong Lu; Lian Ji; Wei He; Pan Dai; Hui Yang…

2011-10-01T23:59:59.000Z

130

Time-evolution of the GaAs(0 0 1) pre-roughening process Z. Ding a,*, D.W. Bullock a  

E-Print Network (OSTI)

Time-evolution of the GaAs(0 0 1) pre-roughening process Z. Ding a,*, D.W. Bullock a , P.M. Thibado reserved. Keywords: Scanning tunneling microscopy; Surface roughening; Surface structure, morphology. the authors observed atomic-scale roughen- ing on GaAs(0 0 1) during growth [8]. From this, Tersoff, Johnson

Thibado, Paul M.

131

Direct determination of exact charge states of surface point defects using scanning tunneling microscopy: As vacancies on GaAs ,,110...  

E-Print Network (OSTI)

microscopy: As vacancies on GaAs ,,110... Kuo-Jen Chao, Arthur R. Smith, and Chih-Kang Shih* Department of the charge state of surface As vacancies on p-type GaAs 110 using scanning tunneling microscopy. This method utilizes the compensation between the local band bending result- ing from the As vacancy and the p

132

Cryogenic growth of Al nitride on GaAs(110): X-ray-photoemission spectroscopy and inverse-photoemission spectroscopy  

Science Journals Connector (OSTI)

We report on our recent studies of Al nitride growth on GaAs(110) formed by depositing Al onto a condensed ammonia overlayer on GaAs(110) at T=90 K using x-ray-photoemission spectroscopy and inverse-photoemission spectroscopy. We have also investigated the temperature dependence of the interface thus formed. The results show some limited amount of Al nitride formed at T=90 K even though the reaction is slow, but the overlayer mostly remains metallic until the substrate is heated up. Much of the reaction of Al with ammonia occurs at about T=170 K, above which the overlayer becomes insulating. The combined information from occupied and unoccupied states reveals new features of the interface formation, and is consistent with our previous synchrotron photoemission studies of Al/NH3/GaAs(100).

Ken T. Park and Y. Gao

1993-02-15T23:59:59.000Z

133

Vacancy-Induced 2×2 Reconstruction of the Ga(111) Surface of GaAs  

Science Journals Connector (OSTI)

Vacancy formation on the GaAs(111) surface is calculated to be strongly exothermic in character. The creation of one vacancy in each 2×2 cell allows the remaining Ga surface atoms to have a large inward relaxation, resulting in a 2.3-eV reduction in energy. It also transforms the polar (111) surface into a nonpolar (110)-like surface. The calculations provide strong support for the vacancy model of Tong et al., which is determined from analysis of low-energy-electron-diffraction data.

D. J. Chadi

1984-05-21T23:59:59.000Z

134

GaAs single quantum dot embedded into AlGaAs nanowire  

SciTech Connect

We report on a study of the photoluminescence spectra taken from quasi one-dimensional and quasi zero-dimensional semiconductor heterostructures. The structures were grown by molecular-beam epitaxy in (111) direction and were cylindrical nanowires based on AlGaAs, of 20 - 50 nm in diameter and 0.5 - 1 ?m in length. Inside the nanowires contain one or two GaAs quantum dots, of 2 nm thick and 15 - 45 nm in diameter. We studied a single nanowire. The photoluminescence and photoluminescence excitation spectra were registered as a function of the intensity of optical excitation.

Kochereshko, V. P.; Kats, V. N. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia and Spin Optics Laboratory, Saint Petersburg State University, Ul'yanovskaya 1, Petrodvorets, St. Petersburg, 198904 (Russian Federation); Platonov, A. V. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg (Russian Federation); Cirlin, G. E.; Bouravleuv, A. D.; Samsonenko, Yu. B. [A.F.Ioffe Physical-Technical Institute, Politekhnicheskaya 26, 194021, St. Petersburg, Russia and St. Petersburg Academic University of the RAS Khlopina 8/3, 195220, St. Petersburg (Russian Federation); Besombes, L.; Mariette, H. [CEA-CNRS group Nanophysique et Semiconducteurs, CEA, INAC, SP2M, and Institut Néel, 17 rue des Martyrs, F-38054 Grenoble (France)

2013-12-04T23:59:59.000Z

135

Structure of negatively charged muonium in n-type GaAs  

Science Journals Connector (OSTI)

Muon level-crossing resonance and muon-spin-rotation measurements on heavily doped n-type GaAs:Si and GaAs:Te show that the majority of positive muons implanted at room temperature form an isolated diamagnetic muonium center located at a high-symmetry site with Ga neighbors along the ?111? direction(s). These experiments, together with theoretical considerations, imply that negatively charged muonium is at or near the tetrahedral interstitial site with four Ga nearest-neighbor atoms. Except for zero-point energy differences, these results should model negatively charged isolated hydrogen in GaAs.

K.H. Chow; R.F. Kiefl; W.A. MacFarlane; J.W. Schneider; D.W. Cooke; M. Leon; M. Paciotti; T.L. Estle; B. Hitti; R.L. Lichti; S.F.J. Cox; C. Schwab; E.A. Davis; A. Morrobel-Sosa; L. Zavieh

1995-05-15T23:59:59.000Z

136

Nucleation and Growth of GaN on GaAs (001) Substrates  

SciTech Connect

The nucleation of GaN thin films on GaAs is investigated for growth at 620 "C. An rf plasma cell is used to generate chemically active nitrogen from N2. An arsenic flux is used in the first eight monolayer of nitride growth to enhance nucleation of the cubic phase. Subsequent growth does not require an As flux to preserve the cubic phase. The nucleation of smooth interfaces and GaN films with low stacking fault densities is dependent upon relative concentrations of active nitrogen species in the plasma and on the nitrogen to gallium flux ratio.

Drummond, Timothy J.; Hafich, Michael J.; Heller, Edwin J.; Lee, Stephen R.; Liliental-Weber, Zuzanna; Ruvimov, Sergei; Sullivan, John P.

1999-05-03T23:59:59.000Z

137

Back-contacted and small form factor GaAs solar cell.  

SciTech Connect

We present a newly developed microsystem enabled, back-contacted, shade-free GaAs solar cell. Using microsystem tools, we created sturdy 3 {micro}m thick devices with lateral dimensions of 250 {micro}m, 500 {micro}m, 1 mm, and 2 mm. The fabrication procedure and the results of characterization tests are discussed. The highest efficiency cell had a lateral size of 500 {micro}m and a conversion efficiency of 10%, open circuit voltage of 0.9 V and a current density of 14.9 mA/cm{sup 2} under one-sun illumination.

Clews, Peggy Jane; Wanlass, Mark W. (National Renewable Energy Laboratory, Golden, CO); Sanchez, Carlos A.; Pluym, Tammy; Cruz-Campa, Jose Luis; Okandan, Murat; Gupta, Vipin P.; Nielson, Gregory N.; Resnick, Paul James

2010-07-01T23:59:59.000Z

138

Ultrafast magneto-photocurrents in GaAs: Separation of surface and bulk contributions  

E-Print Network (OSTI)

We induce ultrafast magneto-photocurrents in a GaAs crystal employing interband excitation with femtosecond laser pulses at room temperature and non-invasively separate surface and bulk contributions to the overall current response. The separation between the different symmetry contributions is achieved by measuring the simultaneously emitted terahertz radiation for different sample orientations. Excitation intensity and photon energy dependences of the magneto-photocurrents for linearly and circularly polarized excitations reveal an involvement of different microscopic origins, one of which we believe is the inverse Spin-Hall effect. Our experiments are important for a better understanding of the complex momentum-space carrier dynamics in magnetic fields.

Schmidt, Christian B; Tarasenko, Sergey A; Bieler, Mark

2015-01-01T23:59:59.000Z

139

Magnetism and transport properties of epitaxial Fe-Ga thin films on GaAs(001)  

SciTech Connect

Epitaxial Fe-Ga thin films in disordered bcc {alpha}-Fe crystal structure (A2) have been grown on GaAs(001) by molecular beam epitaxy. The saturated magnetization (M{sub S}) decreased from 1371 to 1105 kA/m with increasing Ga concentration from 10.5 to 24.3 % at room temperature. The lattice parameter increased with the increase in Ga content because of the larger atomic radius of Ga atom than that of Fe. The increase in carrier density with Ga content caused in lower resistivity.

Duong Anh Tuan; Shin, Yooleemi; Cho, Sunglae [Department of Physics, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Dang Duc Dung [Department of Physics, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet road, Ha Noi (Viet Nam); Vo Thanh Son [Centers for Nanobioenineering and Spintronics, Chungnam National University, Daejon 350-746 (Korea, Republic of)

2012-04-01T23:59:59.000Z

140

Structures of the As-deficient phase on GaAs(001)-(2×4)  

Science Journals Connector (OSTI)

The atomic structures of the GaAs(001)-(2×4) surface have been studied using scanning tunneling microscopy (STM), reflectance difference spectroscopy (RDS), and reflection high-energy electron diffraction (RHEED). While STM images from the ? phase show well-ordered ?2 structures, the ? phase consists of (2×4) structures with surface As dimers locally missing from the basic ?2(2×4) units. Our RDS and RHEED analyses, together with STM observations, clearly show that the missing-dimer defect has local atomic geometry identical to the ?2(2×4) structure.

Akihiro Ohtake

2006-10-19T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

High excitation power photoluminescence studies of ultra-low density GaAs quantum dots  

SciTech Connect

We fabricate GaAs epitaxial quantum dots (QDs) by filling of self-organized nanoholes in AlGaAs. The QDs are fabricated under optimized process conditions and have ultra-low density in the 10{sup 6} cm{sup ?2} regime. At low excitation power the optical emission of single QDs exhibit sharp excitonic lines, which are attributed to the recombination of excitonic and biexcitonic states. High excitation power measurements reveal surprisingly broad emission lines from at least six QD shell states.

Sonnenberg, D.; Graf, A.; Paulava, V.; Heyn, Ch.; Hansen, W. [Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany)

2013-12-04T23:59:59.000Z

142

Coherent optical polarization of bulk GaAs studied by femtosecond photon-echo spectroscopy  

Science Journals Connector (OSTI)

The nonlinear polarization close to the band gap of GaAs is studied by spectrally and temporally resolved four-wave mixing. Excitonic and free carrier contributions both excited within the bandwidth of the 100 fs pulses are distinguished for the first time. The excitonic part dominates at carrier densities below 1016 cm-3. At higher density, nonthermalized free carriers give rise to an additional component resonant to the pulse that shows a photon-echo-like time behavior. Monte Carlo simulations including the coherent polarization and the scattering dynamics of the carriers account for the data.

A. Lohner; K. Rick; P. Leisching; A. Leitenstorfer; T. Elsaesser; T. Kuhn; F. Rossi; W. Stolz

1993-07-05T23:59:59.000Z

143

Four-photon cascade from quadexcitons in a single GaAs quantum dot  

Science Journals Connector (OSTI)

We demonstrate the generation of temporally correlated four photons emitted by the cascade recombination of a quadexciton in a self-assembled GaAs quantum dot (QD) by performing single photon correlation measurements. The cascade decay of the quadexciton involves a triexciton, a biexciton, and an exciton. The emissions of these states are identified in the photoluminescence (PL) spectrum of the QD by cross-correlation measurements. Polarization-resolved cross-correlation measurements show that the polarizations of the four photons are partly correlated. Radiative, nonradiative, and polarization flipping rates in the QD are estimated from the bunching visibilities of the cross-correlation measurements and the PL lifetimes.

Y. Arashida; Y. Ogawa; F. Minami

2011-09-12T23:59:59.000Z

144

A Single Layer of Mn in a GaAs Quantum Well: A Ferromagnet with Quantum Fluctuations  

SciTech Connect

Some of the highest transition temperatures achieved for Mn-doped GaAs have been in &-doped heterostructures with well-separated planes of Mn. But in the absense of magnetic anisotropy, the Mermin-Wagner theorem implies that a single plane of magnetic ions cannot be ferromagnetic. We show that the same mechanism that produces magnetic frustration and suppresses the transition can stabilize ferromagnetic order for a single layer of Mn in a GaAs quantum well. But this comes at the price of quantum fluctuations that suppress the ordered moment from that of a fully saturated ferromagnet.

Melko, Roger G [ORNL; Fishman, Randy Scott [ORNL; Reboredo, Fernando A [ORNL

2007-01-01T23:59:59.000Z

145

High Resolution Parameter Space from a Two Level Model on Semi-Insulating GaAs  

E-Print Network (OSTI)

Semi-insulating Gallium Arsenide (SI-GaAs) samples experimentally show, under high electric fields and even at room temperature, negative differential conductivity in N-shaped form (NNDC). Since the most consolidated model for n-GaAs, namely, "the model", proposed by E. Scholl was not capable to generate the NNDC curve for SI-GaAs, in this work we proposed an alternative model. The model proposed, "the two-valley model" is based on the minimal set of generation recombination equations for two valleys inside of the conduction band, and an equation for the drift velocity as a function of the applied electric field, that covers the physical properties of the nonlinear electrical conduction of the SI-GaAs system. The "two valley model" was capable to generate theoretically the NNDC region for the first time, and with that, we were able to build a high resolution parameter-space of the periodicity (PSP) using a Periodicity-Detection (PD) routine. In the parameter space were observed self-organized periodic structu...

da Silva, S L; de Oliveira, A G; Ribeiro, G M; da Silva, R L

2014-01-01T23:59:59.000Z

146

Bistability of self-modulation of the GaAs intrinsic stimulated picosecond radiation spectrum  

SciTech Connect

The bistability of self-modulation of the spectrum of the stimulated picosecond radiation that appears during picosecond optical pumping of GaAs is detected. The radiation is measured before it reaches the end faces of a sample. One set of equidistant modes occurs in the radiation spectrum at the radiation pulse front. A set of modes located at the center between the initial modes replaces the first set in the descending radiation branch. The intermode interval inside each set coincides with the calculated interval between the eigenmodes of the GaAs layer, which is an active cavity. The radiation rise time turns out to be an oscillating function of the photon energy. The spectrum evolution is self-consistent so that the time-integrated spectrum and the spectrum-integrated radiation pulse envelope have a smooth (without local singularities) shape. The revealed bistability explains the physical nature of the two radiation-induced states of population depletion between which subterahertz self-oscillations in the radiation field were detected earlier. The radiation spectrum self-modulation is assumed to be a variant of stimulated Raman scattering.

Ageeva, N. N.; Bronevoi, I. L., E-mail: bil@cplire.ru; Zabegaev, D. N.; Krivonosov, A. N. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)] [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Russian Federation)

2013-08-15T23:59:59.000Z

147

Wet etching of GaAs using synchrotron radiation x rays  

Science Journals Connector (OSTI)

The results of room-temperature wet etching of GaAs using synchrotron-radiation x rays are described. Under x-rayillumination etching occurs on the n- GaAs surface in contact with an acid or base solution or even deionized water. The etching process is studied as functions of the electrolytes their concentration semiconductor doping level and x-ray intensity and energy. The etching mechanism is determined to be primarily electrochemical in nature but the x-ray radiation chemistry plays a role in the etching. Smoothly etchedsurfaces are achievable with a root-mean-square surface roughness of 0.7–2.0 nm. We also found that the etching rate increases substantially with the ratio of the sample size to the x-ray exposure size. This is accounted for by the rate-limiting effect on the charge transfer across the semiconductor-electrolyte junction. The chemistry of etchedsurfaces is studied using x-ray photoelectron spectroscopy and compared to that of as-received surfaces.

Qing Ma; Nicolaie Moldovan; Derrick C. Mancini; Richard A. Rosenberg

2001-01-01T23:59:59.000Z

148

Structural properties of Bi-terminated GaAs(0 0 1) surface  

Science Journals Connector (OSTI)

Electronic and structural properties of Bi-terminated reconstructions on GaAs(0 0 1) surface have been studied by scanning tunneling microscopy (STM) and synchrotron radiation core-level spectroscopy. A 2–3 monolayer thick Bi-layer was evaporated on a Ga-terminated GaAs(0 0 1) surface. By heating the surface, the reconstruction changed from (2 × 1) to (2 × 4). The ?2 phase with one top Bi dimer and one As or Bi dimer in the third atomic layer per surface unit cell is proposed to explain the STM images of the Bi/GaAs(0 0 1)(2 × 4) surface heated at 400 °C. Bi 5d photoemission from the Bi/GaAs(2 × 4) consisted of two components suggesting two different bonding sites for Bi atoms on the (2 × 4) surface. The variation of the surface sensitivity of the photoemission induced no changes in the intensities of the components indicating that the origins of both components lie in the first surface layer.

M. Ahola-Tuomi; P. Laukkanen; R.E. Perälä; M. Kuzmin; J. Pakarinen; I.J. Väyrynen; M. Adell

2006-01-01T23:59:59.000Z

149

Surface roughening during depth profiling by Secondary Ion Mass Spectrometry (SIMS) in GaAlAs and GaAs  

Science Journals Connector (OSTI)

During bombardment of Ga1?xAlxAs and GaAs with oxygen we found an abrupt transition to higher sputter rates, change of the useful yield and significant increase of surface roughness at a well defined depth, which...

M. Gericke; T. Lill; M. Trapp; C. -E. Richter…

150

IEEE ELECTRON DEVICE LETTERS, VOL. 30, NO. 6, JUNE 2009 593 GaAs MESFET With a High-Mobility  

E-Print Network (OSTI)

systems, including InGaAs [4], CdS [5], ZnO [6], and GaN [7]. To the best of our knowledge FET (MESFET) fabricated with an intentionally doped n-type planar GaAs NW channel grown on a semi

Li, Xiuling

151

Highly Ordered Ga Nanodroplets on a GaAs Surface Formed by a Focused Ion Beam Qiangmin Wei,1  

E-Print Network (OSTI)

Highly Ordered Ga Nanodroplets on a GaAs Surface Formed by a Focused Ion Beam Qiangmin Wei,1 Jie Lian,2,3 Wei Lu,4 and Lumin Wang1,5,* 1 Department of Materials Science and Engineering, University Arbor, Michigan 48109, USA 3 Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer

Lu, Wei

152

Precipitation in Fe-or Ni-implanted and annealed GaAs J. C. P. Changa)  

E-Print Network (OSTI)

of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 E. S. Harmon, M. R. Melloch, and J. M. Woodall School of Electrical Engineering, Purdue University, West Lafayette, Indiana 47907/semiconductor composites by ion implantation of Fe and Ni into GaAs and a subsequent anneal to nucleate clusters. Electron

Woodall, Jerry M.

153

Near-infrared sideband generation induced by intense far-infrared radiation in GaAs quantum wells  

E-Print Network (OSTI)

Near-infrared sideband generation induced by intense far-infrared radiation in GaAs quantum wells J illuminated with near-infrared NIR radiation at frequency nir and intense far-infrared FIR radiation from and quenching of photoluminescence PL .8,9 The nonlinear interaction of FIR and near-infrared NIR radiation

Kono, Junichiro

154

Development of Polarized Electron Source of GaAs-AlGaAs Superlattice and Strained GaAs  

Science Journals Connector (OSTI)

At Nagoya University, we have continued the development of GaAs polarized electron source (PES) for several years. Our test ... a gun producing (1–5) KeV polarized electrons and a standard 100 KeV Mott polarimete...

T. Nakanishi; S. Nakamura

1991-01-01T23:59:59.000Z

155

Photoluminescence from GaAs nanodisks fabricated by using combination of neutral beam etching and atomic hydrogen-assisted molecular beam epitaxy regrowth  

SciTech Connect

We have fabricated GaAs nanodisk (ND) structures by using a combination of neutral beam etching process and atomic hydrogen-assisted molecular beam epitaxy regrowth. We have observed clear photoluminescence (PL) emissions from GaAs NDs. The peak energy showed a blueshift due to the quantum confinement in three spatial dimensions, and it agreed with the theoretically estimated transition energy. The PL results also showed that the cap-layer disks act as radiative recombination centers. We have confirmed that the PL emission originates from the GaAs NDs, and our approach is effective for the fabrication of high quality ND structures.

Kaizu, Toshiyuki; Okada, Yoshitaka [Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Tamura, Yosuke; Igarashi, Makoto; Hu, Weiguo; Tsukamoto, Rikako [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yamashita, Ichiro [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Samukawa, Seiji [Japan Science and Technology Agency, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2012-09-10T23:59:59.000Z

156

Real-time reflectance-difference spectroscopy of GaAs molecular beam epitaxy homoepitaxial growth  

SciTech Connect

We report on real time-resolved Reflectance-difference (RD) spectroscopy of GaAs(001) grown by molecular beam epitaxy, with a time-resolution of 500 ms per spectrum within the 2.3–4.0 eV photon energy range. Through the analysis of transient RD spectra we demonstrated that RD line shapes are comprised of two components with different physical origins and determined their evolution during growth. Such components were ascribed to the subsurface strain induced by surface reconstruction and to surface stoichiometry. Results reported in this paper render RD spectroscopy as a powerful tool for the study of fundamental processes during the epitaxial growth of zincblende semiconductors.

Lastras-Martínez, A., E-mail: alm@cactus.iico.uaslp.mx, E-mail: alastras@gmail.com; Ortega-Gallegos, J.; Guevara-Macías, L. E.; Nuñez-Olvera, O.; Balderas-Navarro, R. E.; Lastras-Martínez, L. F. [Instituto de Investigación en Comunicación Optica, Universidad Autónoma de San Luis Potosí, Alvaro Obregón 64, San Luis Potosí, SLP 78000 (Mexico); Lastras-Montaño, L. A. [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Lastras-Montaño, M. A. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, California 93106 (United States)

2014-03-01T23:59:59.000Z

157

Energy levels of very short?period (GaAs) n ?(AlAs) n superlattices  

Science Journals Connector (OSTI)

The energy levels of very short?period (GaAs) n ?(AlAs) n superlattices (n?4) were investigated by photoluminescence(PL). The results show that these superlattices are type II but the lowest conduction bands are X x y for n?3 and X z for n=4 respectively. (Here X z is the valley with k parallel to the growth axis.) In both cases the X valleys are very close to each other. PL decay PL excitation and PL under uniaxial stress confirm this identification. Al0.5Ga0.5As shows very different behavior showing that even for n=1 our samples are true superlattices.

Weikun Ge; M. D. Sturge; W. D. Schmidt; L. N. Pfeiffer; K. W. West

1990-01-01T23:59:59.000Z

158

Large area, low capacitance, GaAs nanowire photodetector with a transparent Schottky collecting junction  

SciTech Connect

We present experimental results on a GaAs/Indium-Tin-Oxide Schottky-like heterojunction photodetector based on a nanowire device geometry. By distributing the active detecting area over an array of nanowires, it is possible to achieve large area detection with low capacitance. Devices with bare GaAs and passivated AlGaAs/GaAs nanowires are fabricated to compare the responsivity with and without surface passivation. We are able to achieve responsivity of >0.5A/W and Signal-Noise-Ratio in excess of 7?dB for 2?V applied reverse bias with passivated nanowire devices. Capacitance-voltage measurement yields <5?nF/cm{sup 2}, which shows a strong possibility for high-speed applications with a broad area device.

Seyedi, M. A., E-mail: seyedi@usc.edu; Yao, M.; O'Brien, J.; Dapkus, P. D. [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States)] [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States); Wang, S. Y. [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States) [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States); Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California, Santa Cruz, California 95064, USA and NASA Ames Research Center, Moffett Field, California 94035 (United States)

2013-12-16T23:59:59.000Z

159

Intermediate-band material based on GaAs quantum rings for solar cells  

SciTech Connect

The intermediate-band concept is invoked to explain the photoresponse spectra obtained for unbiased devices fabricated from GaAs quantum rings grown by a droplet epitaxy technique on lattice-matched Al{sub 0.3}Ga{sub 0.7}As barriers. The photoresponse spectra where measured at room temperature in the visible-near-infrared spectral range. The presence of the intermediate band in the device active region is confirmed by measuring the mid-infrared photoresponse, which is attributed to the intersubband transitions in the conduction band. The photocurrent was measured at room temperature and found to be about four orders of magnitude larger than the dark current in the voltage range of {+-} 4.0 V.

Wu Jiang; Shao Dali [Department of Electrical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Li Zhenhua; Kunets, Vasyl P.; Wang Zhiming; Salamo, G. J. [Institute of Nanoscale Materials Science and Engineering, Fayetteville, Arkansas 72701 (United States); Manasreh, M. O. [Department of Electrical Engineering, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Institute of Nanoscale Materials Science and Engineering, Fayetteville, Arkansas 72701 (United States)

2009-08-17T23:59:59.000Z

160

Measurement of electron beam polarization from unstrained GaAs via two-photon photoemission  

SciTech Connect

Two-photon absorption of 1560 nm light was used to generate polarized electron beams from unstrained GaAs photocathodes of varying thickness: 625 {mu}m, 0.32 {mu}m, and 0.18 {mu}m. For each photocathode, the degree of spin polarization of the photoemitted beam was less than 50%, contradicting earlier predictions based on simple quantum mechanical selection rules for spherically-symmetric systems but consistent with the more sophisticated model of Bhat et al. (Phys. Rev. B 71 (2005) 035209). Polarization via two-photon absorption was the highest from the thinnest photocathode sample and comparable to that obtained via one-photon absorption (using 778 nm light), with values 40.3 +- 1.0% and 42.6 +- 1.0%, respectively.

McCarter, James L. [Univ. of Virginia, Charlottesville, VA (United States); Afanasev, A. [George Washington Univ., Washingon, DC (United States); Gay, T. J. [Univ. of Nebraska, Lincoln, NE (United States); Hansknecht, John C. [JLAB, Newport News, VA (United States); Kechiantz, A. [George Washington Univ., Washingon, DC (United States); Poelker, B. Matthew [JLAB, Newport News, VA (United States)

2014-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Composite system based on CdSe/ZnS quantum dots and GaAs nanowires  

SciTech Connect

The possibility of fabricating a composite system based on colloidal CdSe/ZnS quantum dots and GaAs nanowires is demonstrated and the structural and emission properties of this system are investigated by electron microscopy and photoluminescence spectroscopy techniques. The good wettability and developed surface of the nanowire array lead to an increase in the surface density of quantum dots and, as a consequence, in the luminosity of the system in the 600-nm wavelength region. The photoluminescence spectrum of the quantum dots exhibits good temperature stability in the entire range 10-295 K. The impact of surface states on energy relaxation and the role of exciton states in radiative recombination in the quantum dots are discussed.

Khrebtov, A. I. [St. Petersburg Academic University-Nanotechnology Research and Education Center, Russian Academy of Sciences (Russian Federation)] [St. Petersburg Academic University-Nanotechnology Research and Education Center, Russian Academy of Sciences (Russian Federation); Talalaev, V. G. [St. Petersburg State University, Fock Institute of Physics (Russian Federation)] [St. Petersburg State University, Fock Institute of Physics (Russian Federation); Werner, P. [Max-Planck-Institut fuer Mikrostukturphysik (Germany)] [Max-Planck-Institut fuer Mikrostukturphysik (Germany); Danilov, V. V. [Vavilov State Optical Institute (Russian Federation)] [Vavilov State Optical Institute (Russian Federation); Artemyev, M. V. [Belarussian State University, Institute for Physicochemical Problems (Belarus)] [Belarussian State University, Institute for Physicochemical Problems (Belarus); Novikov, B. V. [St. Petersburg State University, Fock Institute of Physics (Russian Federation)] [St. Petersburg State University, Fock Institute of Physics (Russian Federation); Shtrom, I. V. [St. Petersburg Academic University-Nanotechnology Research and Education Center, Russian Academy of Sciences (Russian Federation)] [St. Petersburg Academic University-Nanotechnology Research and Education Center, Russian Academy of Sciences (Russian Federation); Panfutova, A. S. [Vavilov State Optical Institute (Russian Federation)] [Vavilov State Optical Institute (Russian Federation); Cirlin, G. E. [St. Petersburg Academic University-Nanotechnology Research and Education Center, Russian Academy of Sciences (Russian Federation)] [St. Petersburg Academic University-Nanotechnology Research and Education Center, Russian Academy of Sciences (Russian Federation)

2013-10-15T23:59:59.000Z

162

Fano Resonance in GaAs 2D Photonic Crystal Nanocavities  

SciTech Connect

We report the results of polarization resolved reflectivity experiments in GaAs air-bridge photonic crystals with L3 cavities. We show that the fundamental L3 cavity mode changes, in a controlled way, from a Lorentzian symmetrical lineshape to an asymmetrical form when the linear polarization of the incident light is rotated in the plane of the crystal. The different lineshapes are well fitted by the Fano asymmetric equation, implying that a Fano resonance is present in the reflectivity. We use the scattering matrix method to model the Fano interference between a localized discrete state (the cavity fundamental mode) and a background of continuum states (the light reflected from the crystal slab in the vicinity of the cavity) with very good agreement with the experimental data.

Valentim, P. T.; Guimaraes, P.S. S. [Departamento de Fisica, Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Instituto Nacional de Ciencia e Tecnologia de Nanodispositivos Semicondutores - INCT-DISSE (Brazil); Luxmoore, I. J.; Szymanski, D.; Whittaker, D. M.; Fox, A. M.; Skolnick, M. S. [Department of Physics and Astronomy, University of Sheffield, Sheffield (United Kingdom); Vasco, J. P. [Instituto de Fisica, Universidad de Antioquia, Medellin (Colombia); Vinck-Posada, H. [Departamento de Fisica, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota (Colombia)

2011-12-23T23:59:59.000Z

163

Infrared spectroscopy of amorphous hydrogenated GaAs: Evidence for H bridges  

Science Journals Connector (OSTI)

The infrared absorption spectra of hydrogenated amorphous GaAs show two prominent hydrogen-related bands at 530 and 1460 cm-1. These bands are very broad and they amount to most of the hydrogen-induced infrared absorption. The remaining structures are a number of comparatively sharp lines which we interpret as Ga-H and As-H modes in partial agreement with earlier investigations. We argue that the broad bands arise from near-stretching (1460 cm-1) and from wagging (530 cm-1) vibrations of H atoms situated in bridging positions between two Ga atoms. This assignment is supported by similar bands in Al-H polymers, a-GaP: H, and a-GaSb: H. A model calculation of the mode frequencies is also presented.

Z. P. Wang; L. Ley; M. Cardona

1982-09-15T23:59:59.000Z

164

Impact ionization in GaAs: A screened exchange density-functional approach  

SciTech Connect

Results are presented of a fully ab initio calculation of impact ionization rates in GaAs within the density functional theory framework, using a screened-exchange formalism and the highly precise all-electron full-potential linearized augmented plane wave method. The calculated impact ionization rates show a marked orientation dependence in k space, indicating the strong restrictions imposed by the conservation of energy and momentum. This anisotropy diminishes as the impacting electron energy increases. A Keldysh type fit performed on the energy-dependent rate shows a rather soft edge and a threshold energy greater than the direct band gap. The consistency with available Monte Carlo and empirical pseudopotential calculations shows the reliability of our approach and paves the way to ab initio calculations of pair production rates in new and more complex materials.

Picozzi, S., Asahi, R., Geller, C.B., Continenza, A., and Freeman, A.J.

2001-08-13T23:59:59.000Z

165

Open-tube method for diffusion of zinc into GaAs  

SciTech Connect

Highly reproducible zinc diffusions from 0.03 to 1.5 /mu/m have been made into GaAs using a CVD zinc-doped silica source capped with phosphosilicate glass. This structure permitted the use of an open-tube, flowing inert gas diffusion system. Diffusions were made from 400/degree/ to 700/degree/C, with surface hole concentrations from 0.1 to 1.0*10/sup 20/ cm/sup -3/, and junction depths from 300A to 1.5 /mu/m. The diffusion coefficient and the hole concentration obtained by this technique are very close to those obtained by sealed ampul techniques using a Zn/sub 3/A/sub 2/ source. However, this open-tube system is more convenient to use, and gives highly reproducible results. 13 refs.

Field, R.J.; Ghandhi, S.K.

1982-07-01T23:59:59.000Z

166

Excitonic and free-carrier polarizations of bulk GaAs studied by femtosecond coherent spectroscopy  

Science Journals Connector (OSTI)

The transient third-order polarization at the band gap of undoped and p-doped GaAs is investigated by spectrally and temporally resolved four-wave mixing. Excitonic and free-carrier contributions simultaneously excited within the bandwidth of the 100-fs pulses are clearly distinguished by their different spectral envelopes. The excitonic part dominates at carrier densities below 1016 cm-3 and shows a time evolution governed by exciton–free-carrier scattering and by many-body effects. At higher density, the free-carrier polarization has a strength similar to the exciton contribution and exhibits a spectrum resonant to the femtosecond pulses with a photon-echo-like temporal behavior. The data are analyzed by a numerical solution of the semiconductor Bloch equations including an ensemble Monte Carlo simulation of the scattering dynamics of the carriers. The theoretical model is in good agreement with the experimental results.

A. Leitenstorfer; A. Lohner; K. Rick; P. Leisching; T. Elsaesser; T. Kuhn; F. Rossi; W. Stolz; K. Ploog

1994-06-15T23:59:59.000Z

167

Photoresponse of the FR3 electron-spin-resonance signal in GaAs  

Science Journals Connector (OSTI)

The photoresponse of the FR3 electron-spin-resonance (ESR) signal in GaAs has been studied. Excitation and quenching of the FR3 ESR is shown to result from the optically induced charge exchange between the FR3 center and the AsGa antisite. The FR3 ESR can be persistently excited with photons in the range 1.0 eV

U. Kaufmann; W. Wilkening; M. Baeumler

1987-11-15T23:59:59.000Z

168

Tailoring broadband light trapping of GaAs and Si substrates by self-organised nanopatterning  

SciTech Connect

We report on the formation of high aspect ratio anisotropic nanopatterns on crystalline GaAs (100) and Si (100) substrates exploiting defocused Ion Beam Sputtering assisted by a sacrificial self-organised Au stencil mask. The tailored optical properties of the substrates are characterised in terms of total reflectivity and haze by means of integrating sphere measurements as a function of the morphological modification at increasing ion fluence. Refractive index grading from sub-wavelength surface features induces polarisation dependent anti-reflection behaviour in the visible-near infrared (VIS-NIR) range, while light scattering at off-specular angles from larger structures leads to very high values of the haze functions in reflection. The results, obtained for an important class of technologically relevant materials, are appealing in view of photovoltaic and photonic applications aiming at photon harvesting in ultrathin crystalline solar cells.

Martella, C.; Chiappe, D.; Mennucci, C.; Buatier de Mongeot, F. [Dipartimento di Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova (Italy)

2014-05-21T23:59:59.000Z

169

Boron-Silicon complex defects in GaAs: An ab initio study  

Science Journals Connector (OSTI)

First principles calculations have been performed to investigate defect equilibria of the silicon–boron pair complex (Si–B) in a GaAs matrix. For several charge states the formation energies were evaluated within the Car–Parrinello scheme considering cation and anion substitutional site defects. The calculations including the full relaxation of all ionic coordinates investigate native defects and isolated substitutional silicon (Si) and boron (B) impurities. The obtained formation energies are used to calculate the impurity concentration for different growth conditions. These results can be used to estimate the effect of different thermal profiles on the distribution and electrical state of Si and B defects which is interesting for classical process simulations.

R. Leitsmann; F. Chicker; Ph. Plänitz; C. Radehaus; U. Kretzer; M. Scheffer-Czygan; S. Eichler

2011-01-01T23:59:59.000Z

170

Self-cleaning and surface recovery with arsine pretreatment in ex situ atomic-layer-deposition of Al2O3 on GaAs  

E-Print Network (OSTI)

. heavily doped GaAs 001 substrates at 650 °C with TMG Ga CH3 3 and arsine AsH3 V/III=23 with disilane Si2H6

171

Simulation of quantum dots size and spacing effect for intermediate band solar cell application based on InAs quantum dots arrangement in GaAs  

SciTech Connect

Intermediate band solar cell (IBSC) has become a promising technology in increasing solar cell efficiency. In this work we compare absorption coefficient profile between InAs quantum dots with GaAs bulk. We calculate the efficiency of GaAs bulk and GaAs doped with 2, 5, and 10 nm InAs quantum dot. Effective distances in quantum dot arrangement based on electron tunneling consideration were also calculated. We presented a simple calculation method with low computing power demand. Results showed that arrangement of quantum dot InAs in GaAs can increase solar cell efficiency from 23.9 % initially up to 60.4%. The effective distance between two quantum dots was found 2 nm in order to give adequate distance to prevent electron tunneling and wave functions overlap.

Hendra, P. I. B., E-mail: ib.hendra@gmail.com; Rahayu, F., E-mail: ib.hendra@gmail.com; Darma, Y., E-mail: ib.hendra@gmail.com [Physical Vapor Deposition Laboratory, Physics of Material Electronics Research, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24T23:59:59.000Z

172

High quality metamorphic graded buffers with lattice-constants intermediate to GaAs an InP for device applications  

E-Print Network (OSTI)

We have investigated the use of a continuous, linear grading scheme for compositionally-graded metamorphic InxGal-As buffers on GaAs, which can be used as virtual substrates for optical emitters operating at wavelengths > ...

Lee, Kenneth Eng Kian

2009-01-01T23:59:59.000Z

173

Piezoelectric surface acoustical phonon amplification in graphene on a GaAs substrate  

SciTech Connect

We study the interaction of Dirac Fermions in monolayer graphene on a GaAs substrate in an applied electric field by the combined action of the extrinsic potential of piezoelectric surface acoustical phonons of GaAs (piezoelectric acoustical (PA)) and of the intrinsic deformation potential of acoustical phonons in graphene (deformation acoustical (DA)). We find that provided the dc field exceeds a threshold value, emission of piezoelectric (PA) and deformation (DA) acoustical phonons can be obtained in a wide frequency range up to terahertz at low and high temperatures. We found that the phonon amplification rate R{sup PA,DA} scales with T{sub BG}{sup S?1} (S=PA,DA), T{sub BG}{sup S} being the Block?Gru{sup ¨}neisen temperature. In the high-T Block?Gru{sup ¨}neisen regime, extrinsic PA phonon scattering is suppressed by intrinsic DA phonon scattering, where the ratio R{sup PA}/R{sup DA} scales with ?1/?(n), n being the carrier concentration. We found that only for carrier concentration n?10{sup 10}cm{sup ?2}, R{sup PA}/R{sup DA}>1. In the low-T Block?Gru{sup ¨}neisen regime, and for n=10{sup 10}cm{sup ?2}, the ratio R{sup PA}/R{sup DA} scales with T{sub BG}{sup DA}/T{sub BG}{sup PA}?7.5 and R{sup PA}/R{sup DA}>1. In this regime, PA phonon dominates the electron scattering and R{sup PA}/R{sup DA}<1 otherwise. This study is relevant to the exploration of the acoustic properties of graphene and to the application of graphene as an acoustical phonon amplifier and a frequency-tunable acoustical phonon device.

Nunes, O. A. C., E-mail: oacn@unb.br [Institute of Physics, University of Brasilia, Brasilia, 70910-900 DF (Brazil)

2014-06-21T23:59:59.000Z

174

Kinetics of GaAs Dissolution in H2O2?NH4OH?H2O Solutions  

Science Journals Connector (OSTI)

Gallium arsenide and other group III?V semiconductors have found numerous applications in the electronics industry because of such characteristics as the direct band gap and higher electron mobility, which make them more suitable than silicon in the fabrication of optoelectronic and high-frequency devices. ... For example, the solubilities of both As2O3 and As2O5 in water increase between 15 and 40 °C (Perry and Phillips, 1995), while Ga2O3 and Ga(OH)3 are insoluble in water and no data are available on the temperature dependence of their solubility at higher pH. ... Both Sheka et al. (1966) and Sidgwick (1950) confirm that gallium hydroxides are particularly soluble in NH4OH. ...

Christine Bryce; Dimitrios Berk

1996-12-04T23:59:59.000Z

175

Microstructure characterization of Cu,Ge/n-type GaAs ohmic contacts M. 0. Aboelfotoh, S. Oktyabrsky, and J. Narayan  

E-Print Network (OSTI)

contacts of Ge/Pd/n-type GaAs have been proposed.4 This contact scheme involves the deposition of a metal at 325 "C for 30 min, the entire layer of Pd is consumed in the formation of a palladium germanide layer to the Ge/Pd contacts,' and that n-channel GaAs metal- semiconductor field-effect transistors using the q

Woodall, Jerry M.

176

EL2-related studies in irradiated and implanted GaAs Laboratoire de Physique de la Matire (associ au CNRS), Institut National des Sciences Appliques de Lyon,  

E-Print Network (OSTI)

donneur profond EL2 est un défaut très important par le rôle qu'il joue dans la compensation du matériau in the compensation of undoped semi-insulating GaAs. The knowledge of the exact EL2 structure becomes of even greater semi-insulating (SI) GaAs uses the liquid- encapsulated Czochralski process with the As vapor pressure

Boyer, Edmond

177

Photocurrent Spectroscopy of CdS/Plastic, CdS/Glass, and ZnTe/GaAs Hetero-pairs Formed with Pulsed-laser Deposition.  

E-Print Network (OSTI)

?? This dissertation presents photocurrent (PC) spectroscopy of thin-film cadmium sulfide (CdS) on plastic, CdS on glass, and zinc telluride (ZnTe) on gallium arsenide (GaAs)… (more)

Acharya, Krishna Prasad

2009-01-01T23:59:59.000Z

178

Formation of anion vacancies by Langmuir evaporation from InP and GaAs (110) surfaces at low temperatures  

Science Journals Connector (OSTI)

A low-temperature Langmuir-evaporation regime is observed by scanning tunneling microscopy on InP and GaAs (110) surfaces. It is characterized by the formation of positively charged anion monovacancies even at room temperature. This vacancy formation has been studied as a function of time on InP between 293 and 480 K and on GaAs at room temperature. On InP the maximum vacancy concentration is obtained at 435 K. At this temperature 1.2% of the P surface sites are vacant. At higher temperatures the concentration decreases. The observations are explained by a competition between, on the one hand, P-vacancy–adatom pair production followed by P2 molecule formation and desorption and, on the other hand, phosphorus outdiffusion from the bulk.

Ph. Ebert, M. Heinrich, M. Simon, K. Urban, and M. G. Lagally

1995-04-15T23:59:59.000Z

179

COMPARATIVE STUDY OF CdTe AND GaAs PHOTOREFRACTIVE PERFORMANCES FROM 1m TO 1.55m  

E-Print Network (OSTI)

1 COMPARATIVE STUDY OF CdTe AND GaAs PHOTOREFRACTIVE PERFORMANCES FROM 1µm TO 1.55µm L.A. de CdTe at different wavelengths from 1.06µm to 1.55µm. The sensitivity and performances of different for the extension of the photorefractive effect towards the wavelength region of 1.3-1.5µm. CdTe appears

Paris-Sud XI, Université de

180

Role of GaAs surface clearing in plasma deposition of silicon nitride films for encapsulated annealing  

SciTech Connect

The role of GaAs surface cleaning and plasma reactor cleaning prior to deposition of silicon nitride films for encapsulated annealing has been investigated. X-ray photoelectron spectroscopy was employed to determine the surface characteristics of GaAs treated with HCl, HF, and NH4OH solutions preceded by a degreasing procedure. The HCl clean left the least amount of oxygen on the surface. Fluorine contamination resulting from the CF4 plasma used to clean the reactor was found to be located at the film-substrate interface by Auger electron spectroscopy with argon-ion sputtering. A modified deposition procedure was developed to eliminate the fluorine contamination. Plasma deposition of silicon nitride encapsulating films was found to modify the I-V characteristics of Schottky diodes subsequently formed on GaAs surface. The reverse current of the diodes was slightly reduced. Substrates implanted with Si at 100 keV and a dose of 5 x 10 to the 12th/sq cm showed a peak electron concentration of 1.7 x 10 to the 17th/cu cm at a depth of 0.1-micron with 60 percent activation after encapsulation and annealing at 800 C for 7 min. 9 references.

Valco, G.J.; Kapoor, V.J.

1985-06-01T23:59:59.000Z

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181

Dual passivation of GaAs (110) surfaces using O{sub 2}/H{sub 2}O and trimethylaluminum  

SciTech Connect

The nucleation and passivation of oxide deposition was studied on defect-free GaAs (110) surfaces to understand passivation of surfaces containing only III-V heterobonds. The passivation process on GaAs (110) was studied at the atomic level using scanning tunneling microscopy while the electronic structure was determined by scanning tunneling spectroscopy (STS). The bonding of the oxidant and reductant were modeled with density functional theory. To avoid Fermi level pinning during gate oxide atomic layer deposition, a dual passivation procedure was required using both a reductant, trimethylaluminum (TMA), and an oxidant, O{sub 2} or H{sub 2}O. Dosing GaAs (110) with TMA resulted in the formation of an ordered complete monolayer of dimethylaluminum which passivates the group V dangling bonds but also forms metal-metal bonds with conduction band edge states. These edge states were suppressed by dosing the surface with oxidants O{sub 2} or H{sub 2}O which selectively react with group III-aluminum bonds. The presence of an ordered Al monolayer with a high nucleation density was indirectly confirmed by XPS and STS.

Kent, Tyler J.; Edmonds, Mary [Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States)] [Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States); Chagarov, Evgueni [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States); Droopad, Ravi [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States)] [Department of Physics, Texas State University, San Marcos, Texas 78666 (United States); Kummel, Andrew C. [Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States) [Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093 (United States); Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093 (United States)

2013-12-28T23:59:59.000Z

182

Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun  

SciTech Connect

RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is expected to improve further. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper.

Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

2010-05-23T23:59:59.000Z

183

Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System  

SciTech Connect

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower part of the UHV range. Measured NEG pump speed is high at pressures above 5×10^?11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.

M.L. Stutzman; P. Adderley; J. Brittian; J. Clark; J. Grames; J. Hansknecht; G.R. Myneni; M. Poelker

2007-05-01T23:59:59.000Z

184

Diffusion-limited kinetics of terrace growth on GaAs(110)  

SciTech Connect

The kinetics of thermal annealing of surface roughness created by low-energy ion bombardment of GaAs(110) is characterized in situ by a low-energy electron diffraction (LEED) spot profile analysis to investigate the underlying diffusion mechanisms involved. The coarsening of the step-and-terrace structure on the partially annealed surface is observed, showing power-law growth of the average terrace width l{approx}t{sup {beta}} with an exponent {beta}=0.23-0.26 over two orders of magnitude in annealing time t in the temperature range 660-740 K. However, the terrace height distribution is shown to vary little with annealing, providing evidence for an Ehrlich-Schwoebel barrier at step edges. The LEED analysis also detects an additional, low amplitude height distribution contributing an interface width of less than 0.03 nm, which is interpreted as elastic deformation around subsurface defects and exhibits much slower relaxation kinetics during annealing than the terrace growth.

Piercy, P.; Castonguay, A.M.-J. [Department of Physics, University of Ottawa, Ottawa, Ontario, K1N 6N5 (Canada)

2005-09-15T23:59:59.000Z

185

Barium iron arsenide, barium cobalt arsenide, barium nickel arsenide single crystals and superconductivity upon cobalt doping  

SciTech Connect

The crystal structure and physical properties of BaFe{sub 2}As{sub 2}, BaCo{sub 2}As{sub 2}, and BaNi{sub 2}As{sub 2} single crystals are surveyed. BaFe{sub 2}As{sub 2} gives a magnetic and structural transition at T{sub N} = 132(1) K, BaCo{sub 2}As{sub 2} is a paramagnetic metal, while BaNi{sub 2}As{sub 2} has a structural phase transition at T{sub 0} = 131 K, followed by superconductivity below {Tc} = 0.69 K. The bulk superconductivity in Co-doped BaFe{sub 2}As{sub 2} below {Tc} = 22 K is demonstrated by resistivity, magnetic susceptibility, and specific heat data. In contrast to the cuprates, the Fe-based system appears to tolerate considerable disorder in the transition metal layers. First principles calculations for BaFe{sub 1.84}Co{sub 0.16}As{sub 2} inter-band scattering due to Co is weak.

Ronning, Filip [Los Alamos National Laboratory; Sefat, A S [ORNL; Mcguire, M M [ORNL; Sales, B [ORNL; Jin, R [ORNL; Mandrus, D [ORNL

2009-01-01T23:59:59.000Z

186

Nuclear radiation detectors based on a matrix of ion-implanted p-i-n diodes on undoped GaAs epilayers  

SciTech Connect

Samples of nuclear detectors which represent matrices of p-i-n diodes were fabricated based on undoped gallium arsenide epitaxial layers by ion implantation technology. The detectors have a size of the active area of 0.4 Multiplication-Sign 0.4 and 0.9 Multiplication-Sign 0.9 cm{sup 2}. Electrical characteristics of fabricated detectors and results of measurements of fast neutrons spectra of {sup 241}Am-Be source by the recoil protons method are discussed.

Baryshnikov, F. M.; Britvich, G. I.; Chernykh, A. V.; Chernykh, S. V.; Chubenko, A. P.; Didenko, S. I.; Koltsov, G. I. [National University of Science and Technology 'MISIS', Leninskiy prospect 4, 119049 Moscow (Russian Federation); Institute for High Energy Physics, Polshhad nauki 1, 142281 Protvino (Russian Federation); National University of Science and Technology 'MISIS', Leninskiy prospect 4, 119049 Moscow (Russian Federation); P.N. Lebedev Physical Institute of the RAS, Leninskiy prospect 53, 119991 Moscow (Russian Federation); National University of Science and Technology 'MISIS', Leninskiy prospect 4, 119049 Moscow (Russian Federation)

2012-11-06T23:59:59.000Z

187

Chirped-pulse manipulated carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs  

SciTech Connect

Chirped pulse controlled carrier dynamics in low-temperature molecular-beam-epitaxy grown GaAs are investigated by degenerate pump-probe technique. Varying the chirped condition of excited pulse from negative to positive increases the carrier relaxation time so as to modify the dispersion and reshape current pulse in time domain. The spectral dependence of carrier dynamics is analytically derived and explained by Shockley-Read Hall model. This observation enables the new feasibility of controlling carrier dynamics in ultrafast optical devices via the chirped pulse excitations.

Lee, Chao-Kuei, E-mail: chuckcklee@yahoo.com [Department of Photonics, National Sun-Yat-Sen University, Kaohsiung 80400, Taiwan (China); Lin, Yuan-Yao [Department of Electrical Engineering, Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30010, Taiwan (China); Lin, Sung-Hui [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Lin, Gong-Ru [Department of Electrical Engineering, Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan (China); Pan, Ci-Ling [Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Physics, National Tsing Hwa University, Hsinchu 30010, Taiwan (China)

2014-04-28T23:59:59.000Z

188

Dopant atom clustering and charge screening induced roughness of electronic interfaces in GaAs p-n multilayers  

Science Journals Connector (OSTI)

The roughness of the electronic interfaces of p-n GaAs multilayers is investigated by cross-sectional scanning tunneling microscopy. Two physically different contributions to the roughness are found, both much larger than the underlying atomically sharp “metallurgical” interface. The roughness arises from the individual electrostatic screening fields around each dopant atom near the interface and from a clustering of dopant atoms. The latter leads to charge-carrier-depleted zones extending locally through the entire nominally homogeneously doped layer for layer thicknesses close to the cluster dimension, hence limiting the precision of the spatial and energetic positioning of the Fermi energy in nanoscale semiconductor structures.

N. D. Jäger, K. Urban, E. R. Weber, and Ph. Ebert

2002-05-24T23:59:59.000Z

189

Changes of defect and active-dopant concentrations induced by annealing of highly Si-doped GaAs  

Science Journals Connector (OSTI)

We identified point defects and dopant atoms and measured their concentrations in as-grown and post-growth annealed highly Si-doped GaAs by scanning tunneling microscopy. The annealing under As atmosphere reduces the concentration of Si atoms incorporated into Si pairs and clusters by cluster dissolution, while the concentrations of Si donors, Si donor–Ga vacancy complexes, and Si donor–As vacancy complexes increase. For the dissolution of the Si clusters during heat treatment, a Ga-vacancy-mediated mechanism is suggested.

C. Domke, Ph. Ebert, and K. Urban

1998-02-15T23:59:59.000Z

190

Electronic properties of adsorbates on GaAs,,001...-c,,28.../,,24... Darby L. Winn, Michael J. Hale, Tyler J. Grassman, Jonathan Z. Sexton, and  

E-Print Network (OSTI)

Electronic properties of adsorbates on GaAs,,001...-c,,2Ã?8.../,,2Ã?4... Darby L. Winn, Michael J tunneling spectroscopy STS and density functional theory DFT were used to study four different adsorbates' O that out of the four adsorbates studied, only one left the Fermi level unpinned, Ga2O. DFT calculations

Kummel, Andrew C.

191

Spin-Cast Deposition of CdSe-CdS Core-Shell Colloidal Quantum Dots on Doped GaAs Substrates: Structural and Optical Characterization  

Science Journals Connector (OSTI)

The detailed study of the effects of spin recipe and GaAs substrate doping (i.e., semi-insulating, n-type, or p-type) on the structural and optical properties of spin-cast CdSe-CdS core-shell CQDs provides insight into the surface adsorption and charge ... Keywords: Charge transfer, colloidal quantum dots, hybrid junctions, photoluminescence

A. D. Stiff-Roberts; Wanming Zhang; Jian Xu; Hongying Peng; H. O. Everitt

2007-07-01T23:59:59.000Z

192

Metal-insulator-semiconductor structure on low-temperature grown GaAs M. Young, W. Li, and T. P. Ma  

E-Print Network (OSTI)

Metal-insulator-semiconductor structure on low-temperature grown GaAs A. Chen,a M. Young, W. Li Received 28 July 2006; accepted 30 October 2006; published online 7 December 2006 The metal-insulator dielectrics and metal-insulator-semiconductor MIS structures; for ex- ample, in situ deposited Ga2O3 Gd2O3

Woodall, Jerry M.

193

ELSEWER Journal of Magnetism and Magnetic Materials 169 (1997) 261-270 Superparamagnetic behavior of Fe,GaAs precipitates in GaAs  

E-Print Network (OSTI)

ELSEWER Journal of Magnetism and Magnetic Materials 169 (1997) 261-270 Superparamagnetic behavior; revised 6 December 1996 Abstract We present magnetization measurements on Fe3GaAs clusters distributed-dependent magnetization well above the blocking temperature indicate a particle size distribution in agreement

Woodall, Jerry M.

194

Vacancy migration, adatom motion, a.nd atomic bistability on the GaAs(110) surface studied by scanning tunneling microscopy  

E-Print Network (OSTI)

Vacancy migration, adatom motion, a.nd atomic bistability on the GaAs(110) surface studied temperature are reported. The slow dynamic behavior of vacancies and As adatoms can be resolved within a time scale of about one minute, The vacancies and As adatoms are observed to move preferably along the [110

195

Photovoltaic Single-Crystalline, Thin-Film Cell Basics | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Single-Crystalline, Thin-Film Cell Basics Single-Crystalline, Thin-Film Cell Basics Photovoltaic Single-Crystalline, Thin-Film Cell Basics August 20, 2013 - 2:50pm Addthis Single-crystalline thin films are made from gallium arsenide (GaAs), a compound semiconductor that is a mixture of gallium and arsenic. Gallium arsenide (GaAs) is a compound semiconductor, a mixture of gallium and arsenic. Gallium is a byproduct of the smelting of other metals, notably aluminum and zinc, and it is rarer than gold. Arsenic is not rare, but it is poisonous. Gallium arsenide has been developed for use in solar cells at about the same time that it has been developed for light-emitting diodes, lasers, and other electronic devices that use light. GaAs solar cells offer several benefits: The GaAs bandgap is 1.43 eV-nearly ideal for single-junction solar

196

Magnetic anisotropies in epitaxial Fe{sub 3}O{sub 4}/GaAs(100) patterned structures  

SciTech Connect

Previous studies on epitaxial Fe{sub 3}O{sub 4} rings in the context of spin-transfer torque effect have revealed complicated and undesirable domain structures, attributed to the intrinsic fourfold magnetocrystalline anisotropy in the ferrite. In this Letter, we report a viable solution to this problem, utilizing a 6-nm-thick epitaxial Fe{sub 3}O{sub 4} thin film on GaAs(100), where the fourfold magnetocrystalline anisotropy is negligible. We demonstrate that in the Fe{sub 3}O{sub 4} planar wires patterned from our thin film, such a unique magnetic anisotropy system has been preserved, and relatively simple magnetic domain configurations compared to those previous reports can be obtained.

Zhang, W., E-mail: xiaotur@gmail.com; Zhang, D.; Yuan, S. J.; Huang, Z. C.; Zhai, Y. [Department of Physics, Southeast University, Nanjing 211189 (China); Wong, P. K. J. [NanoElectronics Group, MESA Institute for Nanotechnology, University of Twente, P. O. Box 217, 7500 AE Enschede (Netherlands); Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 (Singapore); Wu, J. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Xu, Y. B. [Spintronics and Nanodevice Laboratory, Department of Electronics, University of York, York, YO10 5DD (United Kingdom)

2014-10-15T23:59:59.000Z

197

k?p results for the absolute absorption coefficients of GaAs and biaxially strained ZnTe  

Science Journals Connector (OSTI)

Our calculations of the absolute absorption coefficients of GaAs and biaxially strained ZnTe single crystal layers is based on a 14×14 k?p model description of the band structure close to the Brillouin-zone center of the direct-gap zinc-blende semiconductors. The parameters of this model (momentum matrix elements, band separations at the ? point, effective masses) are known from fitting to independent experiments. The interband absorption continuum near the fundamental gap is calculated by multiplying the single-particle absorption coefficients from heavy- and light-hole valence bands with separate Sommerfeld corrections in order to account for the electron-hole interaction. Our theoretical results, which are obtained without any fitting parameters, are in good quantitative agreement with experimental data.

H. Mayer; U. Rössler; M. Ruff

1993-05-15T23:59:59.000Z

198

Capture of hot holes by shallow acceptors in p-type GaAs studied by picosecond infrared spectroscopy  

Science Journals Connector (OSTI)

Picosecond recombination of free holes with shallow acceptors in p-doped GaAs is directly monitored via spectrally and temporally resolved infrared studies. Neutral Zn impurities are photoionized by picosecond excitation in the wavelength range around 5 ?m. The recombination dynamics of the free carriers with ionized acceptors is measured via transient changes of the acceptor deionization band at photon energies close to the band gap. Hole capture is observed on a time scale of up to 100 ps following nonexponential kinetics. The data are analyzed with the help of model calculations considering single-step as well as multiple-step trapping mechanisms. Emission of single longitudinal-optical phonons is found to be the main mechanism of picosecond recombination.

M. Woerner; A. Lohner; T. Elsaesser; W. Kaiser

1993-05-15T23:59:59.000Z

199

Strong enhancement of terahertz emission from GaAs in InAs/GaAs quantum dot structures  

SciTech Connect

We report on the intense terahertz emission from InAs/GaAs quantum dot (QD) structures grown by molecular beam epitaxy. Results reveal that the QD sample emission was as high as 70% of that of a p-type InAs wafer, the most intense semiconductor emitter to date. Excitation wavelength studies showed that the emission was due to absorption in strained undoped GaAs, and corresponds to a two order-of-magnitude enhancement. Moreover, it was found that multilayer QDs emit more strongly compared with a single layer QD sample. At present, we ascribe the intense radiation to huge strain fields at the InAs/GaAs interface.

Estacio, Elmer; Pham, Minh Hong; Takatori, Satoru; Cadatal-Raduban, Marilou; Nakazato, Tomoharu; Shimizu, Toshihiko; Sarukura, Nobuhiko [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Somintac, Armando; Defensor, Michael; Awitan, Fritz Christian B.; Jaculbia, Rafael B.; Salvador, Arnel [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Garcia, Alipio [Department of Physical Sciences, University of the Philippines, Baguio City 2600 (Philippines)

2009-06-08T23:59:59.000Z

200

Perpendicular-to-Parallel Spin Reorientation in a Mn-Doped GaAs Quantum Canting or Phase Separation  

SciTech Connect

It is well known that the magnetic anisotropy in a compressively-strained Mn-doped GaAs film changes from perpendicular to parallel with increasing hole concentration p. We study this reorientation transition at T = 0 for a quantum well with Mn impurities confined to the z = 0 plane. With increasing p, the angle 0 that minimizes the energy E increases continuously from 0 (perpendicular anisotropy) to /2 (parallel anisotropy) within some range of p. The shape of Emin(p) suggests that the quantum well becomes phase separated with regions containing low hole concentrations and perpendicular moments interspersed with other regions containing high hole concentrations and parallel moments. However, consideration of the Coulomb energy costs associated with phase separation suggests that the true magnetic state in the transition region is canted with 0 < < /2.

Fishman, Randy Scott [ORNL; Reboredo, Fernando A [ORNL; Brandt, Alex B [ORNL; Moreno, Juana [University of North Dakota, Grand Forks

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Kinetics of band bending and electron affinity at GaAs(001) surface with nonequilibrium cesium overlayers  

SciTech Connect

The dosage dependences of surface band bending and effective electron affinity under cesium deposition on the Ga-rich GaAs(001) surface, along with the relaxation of these electronic properties after switching off the Cs source are experimentally studied by means of modified photoreflectance spectroscopy and photoemission quantum yield spectroscopy. At small Cs coverages, below half of a monolayer, additional features in the dosage dependence and subsequent downward relaxation of the photoemission current are determined by the variations of band bending. At coverages above half of a monolayer the upward relaxation of the photocurrent is caused supposedly by the decrease of the electron affinity due to restructuring in the nonequilibrium cesium overlayer.

Zhuravlev, A. G.; Savchenko, M. L.; Paulish, A. G.; Alperovich, V. L. [Rzhanov Institute of Semiconductor Physics, Lavrentieva, 13, 630090 Novosibirsk, Russia and Novosibirsk State University, Pirogova, 2, 630090 Novosibirsk (Russian Federation); Scheibler, H. E.; Jaroshevich, A. S. [Rzhanov Institute of Semiconductor Physics, Lavrentieva, 13, 630090 Novosibirsk (Russian Federation)

2013-12-04T23:59:59.000Z

202

Ga-assisted catalyst-free growth mechanism of GaAs nanowires by molecular beam epitaxy  

Science Journals Connector (OSTI)

The mechanisms of Ga-assisted GaAs nanowires grown by molecular beam epitaxy are addressed. The axial and radial growth rates as a function of the Ga rate and As pressure indicate that on the opposite of what is observed in thin film epitaxy, the growth rate of the nanowires is arsenic limited. As a consequence, the axial growth rate of the wires can be controlled by the As4 pressure. Additionally, due to the small As4 pressure leading to nanowire growth, the deposition on the facets is very slow, leading to a much lower radial growth rate. Finally, we present a model that is able to accurately describe the presented observations and predicts a maximum length of nontapered nanowires of 40?m.

C. Colombo; D. Spirkoska; M. Frimmer; G. Abstreiter; A. Fontcuberta i Morral

2008-04-28T23:59:59.000Z

203

Calculations of bound and resonant electronic states for the GaAs (111) (2x2) reconstructed surface  

E-Print Network (OSTI)

the degree ol' MASTER OF SCIEVCE December 19ftg Major Subject: Phys)cs CALCULATIONS OF BOUND AiND RESONAiNT ELECTRONIC STATES FOR THE GaAs [111) (2x2) RECONSTRUCTED SURFACE A Thesis by SAMUEL STEPHEiN BLOUNT Approved as to style and content by...), ? 3eV. & E & 2eV 8] (0. 2859, 0. 2268), ? 13eV. & E & ? 8eV. . 82 (0. 2859, 0. 2268). ? 8el'. & E & ? 3eV. . . 83 (0. 2859, 0. 2268), ? 3eV. & E & 2eV. 84 (0. 3569, 0, 2268), ? 13eV ( E & ? 8eV. . 76 (0. 3569, 0. 2268), ? 8eV. & E & ? 3eV. . . 77...

Blount, Samuel Stephen

2012-06-07T23:59:59.000Z

204

Carrier-induced change in refractive index of InP, GaAs, and InGaAsP  

SciTech Connect

The authors have theoretically estimated the change in refractive index {Delta}{ital n} produced by injection of free carriers in InP, GaAs, and InGaAsP. Bandfilling (Burstein-Moss effect), band-gap shrinkage, and free-carrier absorption (plasma effect) were included. Carrier concentrations of 10{sup 16}/cm{sup 3} to 10{sup 19}/cm{sup 3} and photon energies of 0.8 to 2.0 eV were considered. Predictions of {Delta}{ital n} are in reasonably good agreement with the limited experimental data available. Refractive index changes as large as 10{sup {minus} 2} are predicted for carrier concentrations of 10{sup 18}/cm{sup 3}, suggesting that low-loss optical phase modulators and switches using carrier injection are feasible in these materials.

Bennett, B.R. (Dept. of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA (US)); Soref, R.A. (Solid State Sciences Directorate, Rome Air Development Center, Hanscom Air Force Base, Bedford, MA (US)); Del Alamo, J.A. (Dept. of Electrical Engineering and Computer Science, Massachussets Institute of Technology, Cambridge, MA (US))

1990-01-01T23:59:59.000Z

205

Electron Transport Behavior on Gate Length Scaling in Sub-50 nm GaAs Metal Semiconductor Field Effect Transistors  

SciTech Connect

Short channel GaAs Metal Semiconductor Field Effect Transistors (MESFETs) have been fabricated with gate length to 20 nm, in order to examine the characteristics of sub-50 nm MESFET scaling. Here the rise in the measured transconductance is mainly attributed to electron velocity overshoot. For gate lengths below 40 nm, however, the transconductance drops suddenly. The behavior of velocity overshoot and its degradation is investigated and simulated by using a transport model based on the retarded Langevin equation (RLE). This indicates the existence of a minimum acceleration length needed for the carriers to reach the overshoot velocity. The argument shows that the source resistance must be included as an internal element, or appropriate boundary condition, of relative importance in any model where the gate length is comparable to the inelastic mean free path of the carriers.

Han, Jaeheon [Department of Electronic Engineering, Kangnam University, 111 Gugal-dong, Giheung-gu, Yongin-city, Gyeonggi-do, Korea 446-702 (Korea, Republic of)

2011-12-23T23:59:59.000Z

206

Investigation of ultrafast photothermal surface expansion and diffusivity in GaAs via laser-induced dynamic gratings  

SciTech Connect

This thesis details the first direct ultrafast measurements of the dynamic thermal expansion of a surface and the temperature dependent surface thermal diffusivity using a two-color reflection transient grating technique. Studies were performed on p-type, n-type, and undoped GaAs(100) samples over a wide range of temperatures. By utilizing a 90 fs ultraviolet probe with visible excitation beams, the effects of interband saturation and carrier dynamics become negligible; thus lattice expansion due to heating and subsequent contraction caused by cooling provided the dominant influence on the probe. At room temperature a rise due to thermal expansion was observed, corresponding to a maximum net displacement of {approximately} 1 {Angstrom} at 32 ps. The diffracted signal was composed of two components, thermal expansion of the surface and heat flow away from the surface, thus allowing a determination of the rate of expansion as well as the surface thermal diffusivity, D{sub S}. By varying the fringe spacing of the grating, this technique has the potential to separate the signal contributions to the expansion of the lattice in the perpendicular and parallel directions. In the data presented here a large fringe spacing was used, thus the dominant contribution to the rising edge of the signal was expansion perpendicular to the surface. Comparison of he results with a straightforward thermal model yields good agreement over a range of temperatures (20--300{degrees}K). Values for D{sub S} in GaAs were measured and found to be in reasonable agreement with bulk values above 50{degrees}K. Below 50{degrees}K, D{sub S} were determined to be up to an order of magnitude slower than the bulk diffusivity due to increased phonon boundary scattering. The applicability and advantages of the TG technique for studying photothermal and photoacoustic phenomena are discussed.

Pennington, D.M.

1992-04-01T23:59:59.000Z

207

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output  

SciTech Connect

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products.

Dinetta, L.C.; Hannon, M.H.

1995-10-01T23:59:59.000Z

208

Strain modified/enhanced ferromagnetism in Mn{sub 3}Ge{sub 2} thin films on GaAs(001) and GaSb(001)  

SciTech Connect

Ferromagnetic Mn{sub 3}Ge{sub 2} thin films were successfully grown on GaAs(001) and GaSb(001) substrates using molecular beam epitaxy. The results of our work revealed that the substrate facilitates to modify magnetic and electrical properties of Mn{sub 3}Ge{sub 2} films due to tensile/compressive strain effect between films and substrates. The characteristic spin-flopping transition at around 150 K for the bulk Mn{sub 3}Ge{sub 2} disappeared completely for both samples. The antiferromagnetism below 150 K changed to ferromagnetism and retained above room temperature. The saturation magnetization was found to be 0.23 and 1.32 {mu}{sub B}/Mn atom at 10 K for the samples grown on GaSb(001) and GaAs(001), respectively.

Dang Duc Dung; Duong Van Thiet [Department of Physics, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Department of General Physics, School of Engineering Physics, Ha Noi University of Science and Technology, 1 Dai Co Viet Road, Ha Noi (Viet Nam); Feng Wuwei; Cho, Sunglae [Department of Physics, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Park, In-Sung [Department of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Bo Lee, Sung [Department of Materials Science and Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

2013-04-21T23:59:59.000Z

209

Photoacoustic signals of n-type GaAs layers grown by molecular-beam epitaxy on semi-insulating substrates  

Science Journals Connector (OSTI)

Piezoelectric photoacoustic (PA) measurements of molecular-beam-epitaxial (MBE) -grown GaAs layers were carried out in the temperature range from 90 to 290 K. A broad D band with a maximum near 1.3 eV and a sharp Q peak at 1.485 eV have been observed in the 90-K spectra. They vanish in a presence of secondary light illumination. By comparing with optical-absorption spectra, it is considered that the D band is due to electron transitions involving EL2 deep defect levels in the GaAs substrate. The PA signal is considered to be enhanced by the presence of the electric field at the interface between the MBE layer and the substrate. The Q peak is attributed to electron transitions from shallow acceptors such as carbon in GaAs. Observed photoinduced changes in the spectra are explained by a reduction of the electric field in the depletion region which is induced by optical carrier generation.

T. Ikari; A. Fukuyama; K. Maeda; K. Futagami; S. Shigetomi; Y. Akashi

1992-10-15T23:59:59.000Z

210

Metal organic chemical vapor deposition of 111-v compounds on silicon  

DOE Patents (OSTI)

Expitaxial composite comprising thin films of a Group III-V compound semiconductor such as gallium arsenide (GaAs) or gallium aluminum arsenide (GaAlAs) on single crystal silicon substrates are disclosed. Also disclosed is a process for manufacturing, by chemical deposition from the vapor phase, epitaxial composites as above described, and to semiconductor devices based on such epitaxial composites. The composites have particular utility for use in making light sensitive solid state solar cells.

Vernon, Stanley M. (Wellesley, MA)

1986-01-01T23:59:59.000Z

211

Exciton-exciton and exciton-phonon interactions in an interfacial GaAs quantum dot ensemble  

Science Journals Connector (OSTI)

Using optical two-dimensional Fourier transform spectroscopy, we report temperature- and excitation-density-dependent measurements of the homogeneous linewidth of the exciton ground-state transition in a single layer of interfacial GaAs quantum dots (QDs). We show that the homogeneous linewidth increases nonlinearly with temperature from 6 to 50 K and that the thermal broadening is well described by an activation term and offset. The absence of a phonon-activation peak in the two-dimensional spectra reveals that elastic scattering of excitons with acoustic phonons via virtual transitions between the ground and excited states significantly contributes to the thermal broadening. We find that the combination of increasing virtual activation energy and exciton-phonon coupling strength with decreasing QD size results in greater thermal broadening for excitons localized in smaller QDs. The homogeneous linewidth also exhibits a strong excitation-density dependence and is shown to increase linearly as the photon density increases from 2×1011 to 1×1012 photons pulse-1 cm-2 at 6 K. This trend is attributed to strong coupling of excitons within the same QD and is independent of the quantum-well exciton population density.

G. Moody; M. E. Siemens; A. D. Bristow; X. Dai; D. Karaiskaj; A. S. Bracker; D. Gammon; S. T. Cundiff

2011-03-23T23:59:59.000Z

212

A critical discussion of emission mechanisms and reaction rates for the ion?assisted etching of GaAs(100)  

Science Journals Connector (OSTI)

Emission mechanisms and reaction rates for the ion?assisted etching of GaAs(100) have been studied in detail using energetic argon ions and chlorine gas. Ion energies of 500 and 1000 eV were used with chlorine/argon ion surface?flux ratios of 1–120. The m a j o r molecular etchant products were found to be GaCl2 and AsCl3. Gas phase products were detected at different flight distances to investigate the nature of surface residence times. It is concluded based on these measurements that GaCl2 emission is best interpreted in terms of the collisional?cascade sputteringmodel for the specific range of ion energies and surface?flux ratios studied. Using a similar analysis it is concluded that AsCl3 may be emitted by either the thermal desorption or the collisional?cascade mechanisms with the former favored in the range of higher surface?flux ratios and lower ion energies. Furthermore the thermal desorption of AsCl3 appears to follow a first?order surface process. Comparison of our data with those of others indicates general agreement. However more extended analysis based on a broader and more intensive data base leads to some important distinctions among the final conclusions regarding the emission mechanisms.

W. L. O’Brien; C. M. Paulsen?Boaz; T. N. Rhodin; L. C. Rathbun

1988-01-01T23:59:59.000Z

213

Deep Levels in p-Type InGaAsN Lattice Matched to GaAs  

SciTech Connect

Deep level transient spectroscopy (DLTS) measurements were utilized to investigate deep level defects in metal-organic chemical deposition (MOCVD)-grown unintentionally doped p-type InGaAsN films lattice matched to GaAs. The as-grown material displayed a high concentration of deep levels distributed within the bandgap, with a dominant hole trap at E{sub v} + 0.10 eV. Post-growth annealing simplified the deep level spectra, enabling the identification of three distinct hole traps at 0.10 eV, 0.23 eV, and 0.48 eV above the valence band edge, with concentrations of 3.5 x 10{sup 14} cm{sup {minus}3}, 3.8 x 10{sup 14} cm{sup {minus}3}, and 8.2 x 10{sup 14} cm{sup {minus}3}, respectively. A direct comparison between the as-grown and annealed spectra revealed the presence of an additional midgap hole trap, with a concentration of 4 x 10{sup 14} cm{sup {minus}3} in the as-grown material. The concentration of this trap is sharply reduced by annealing, which correlates with improved material quality and minority carrier properties after annealing. Of the four hole traps detected, only the 0.48 eV level is not influenced by annealing, suggesting this level may be important for processed InGaAsN devices in the future.

Allerman, A.A.; Jones, E.D.; Kaplar, R.J.; Kurtz, S.R.; Kwon, D.; Ringel, S.A.

1999-03-02T23:59:59.000Z

214

Selfsimilar and fractal analysis of n-type delta-doped quasiregular GaAs quantum wells  

SciTech Connect

We study the electronic structure of n-type delta-doped quantum wells in GaAs in which the multiple well system is built according to the Fibonacci sequence. The building blocks A and B correspond to delta-doped wells with impurities densities n{sub 2DA} and n{sub 2DB}, and the same well width. The Thomas-Fermi approximation, the semi-empirical sp{sub 3}s* tight-binding model including spin, the Surface Green Function Matching method and the Transfer Matrix approach were implemented to obtain the confining potential, the electronic structure and the selfsimilarity of the spectrum. The fragmentation of the electronic spectra is observed whenever the building blocks A and B interact and it increases as the difference of impurities density between A and B increases as well. The wave function of the first sate of the fragmented bands presents critical characteristics, this is, it is not a localized state nor a extended one as well as it has selfsimilar features. So, the quasiregular characteristics are preserved irrespective of the complexity of the system and can affect the performance of devices based on these structures.

García-Cervantes, H.; Rodríguez-Vargas, I. [Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad Esquina Con Paseo La Bufa S/N, 98060 Zacatecas, Zac. (Mexico)

2014-05-15T23:59:59.000Z

215

Laser-Driven Growth of Silver Nanoplates on p-Type GaAs Substrates and Their Surface-Enhanced Raman Scattering Activity  

Science Journals Connector (OSTI)

Laser-Driven Growth of Silver Nanoplates on p-Type GaAs Substrates and Their Surface-Enhanced Raman Scattering Activity ... Each wafer was cut into ?1 cm × 1 cm square pieces along their cleavage planes (i.e., [01?1?] and [01?1]) and were cleaned by immersing them in a 2% hydrofluoric acid (HF) aqueous solution (Fisher) for 5 min. ... Continued growth smoothes the stepped edges of the oligomers and fuses them into thicker nanoplates whose thicknesses are approximately equal to the sum of the individual plate thicknesses before fusion (Figure 5c). ...

Yugang Sun; Matthew Pelton

2009-03-20T23:59:59.000Z

216

Magneto-transport properties of InAs nanowires laterally-grown by selective area molecular beam epitaxy on GaAs (110) masked substrates  

SciTech Connect

We prepared InAs nanowires (NWs) by lateral growth on GaAs (110) masked substrates in molecular beam epitaxy. We measured magneto-transport properties of the InAs NWs. In spite of parallel-NW multi-channels, we observed fluctuating magneto-conductance. From the fluctuation, we evaluated phase coherence length as a function of measurement temperature, and found decrease in the length with increase in the temperature. We also evaluate phase coherence length as a function of gate voltage.

Akabori, M.; Yamada, S. [Center for Nano-Materials and Technology, Japan Advanced Institute of Science and Technology, 1-1, Asahidai, Nomi, Ishikawa 923-1292 (Japan)

2013-12-04T23:59:59.000Z

217

Observation and Measurement of Temperature Rise and Distribution on GaAs Photo-cathode Wafer with a 532nm Drive Laser and a Thermal Imaging Camera  

SciTech Connect

Significant temperature rise and gradient are observed from a GaAs photo-cathode wafer irradiated at various power levels with over 20W laser power at 532nm wavelength. The laser power absorption and dissipated thermal distribution are measured. The result shows a clear indication that proper removal of laser induced heat from the cathode needs to be considered seriously when designing a high average current or low quantum efficiency photo-cathode electron gun. The measurement method presented here provides a useful way to obtain information about both temperature and thermal profiles, it also applies to cathode heating study with other heating devices such as electrical heaters.

Shukui Zhang, Stephen Benson, Carlos Hernandez-Garcia

2011-03-01T23:59:59.000Z

218

Designing Asynchronous Circuits in Gallium Arsenide  

E-Print Network (OSTI)

3.2.2 Super Buffered Fet Logic : : : : : : : : : : : : : : : : : 18 4 A New Logic Family 21 4.1 Input Stage : : : : : : : : : : : : : : : : : : : : : : : : : : : : 21 4.1.1 Inverter : : : : : : : : : : : : : : : : : : : : : : : : 34 5.2.2 Output stage : : : : : : : : : : : : : : : : : : : : : : : 36 5.2.3 Delay model and power

Martin, Alain

219

Persistent exciton-type many-body interactions in GaAs quantum wells measured using two-dimensional optical spectroscopy  

Science Journals Connector (OSTI)

Studies have shown that many-body interactions among semiconductor excitons can produce distinct features in two-dimensional optical spectra. However, to the best of our knowledge, the dynamics of many-body interactions have not been measured in two-dimensional (2D) spectroscopy studies. Here we measure 2D spectra of GaAs quantum wells at many different “waiting” times and study the time dependence of the spectral features. Characteristic signatures of exciton polarization correlations manifest in the diagonal peaks decay at the exciton dephasing rate, consistent with theoretical predictions. Other many-body interactions manifest in off-diagonal features decay much more slowly. These persistent off-diagonal features must be due to many-body interactions involving exciton populations, and their persistence cannot be predicted by theoretical descriptions restricted to the coherent limit.

Daniel B. Turner; Patrick Wen; Dylan H. Arias; Keith A. Nelson; Hebin Li; Galan Moody; Mark E. Siemens; Steven T. Cundiff

2012-05-15T23:59:59.000Z

220

Critical size for the generation of misfit dislocations and their effects on electronic properties in GaAs nanosheets on Si substrate  

SciTech Connect

While nanowires and nanosheets (NSs) grown on lattice-mismatched substrates have a number of promising technological applications such as solar cells, generation of misfit dislocations (MFDs) at their interfaces is a major concern for the efficiency of these devices. Here, combined molecular-dynamics and quantum-mechanical simulations are used to study MFDs at the interface between a GaAs NS and a Si substrate. Simulation results show the existence of a critical NS thickness, below which NSs are grown free of MFDs. The calculated critical thickness value is consistent with available experimental observations. Charge transfer at the MFD core is found to modify the electronic band profile at the GaAs/Si interface significantly. These effects should have profound impacts on the efficiency of lattice-mismatched NS devices.

Yuan, Zaoshi [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States) [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025 (United States); Shimamura, Kohei [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States) [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Fukuoka 819-0395 (Japan); Shimojo, Fuyuki [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States) [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan); Nakano, Aiichiro [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States)] [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States)

2013-08-21T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

InGaAs heterostructure formation in catalyst-free GaAs nanopillars by selective-area metal-organic vapor phase epitaxy  

SciTech Connect

We investigate axial GaAs/InGaAs/GaAs heterostructures embedded in GaAs nanopillars via catalyst-free selective-area metal-organic chemical vapor deposition. Structural characterization by transmission electron microscopy with energy dispersive x-ray spectroscopy (EDS) indicates formation of axial In{sub x}Ga{sub 1-x}As (x{approx}0.20) inserts with thicknesses from 36 to 220 nm with {+-}10% variation and graded Ga:In transitions controlled by In segregation. Using the heterointerfaces as markers, the vertical growth rate is determined to increase linearly during growth. Photoluminescence from 77 to 290 K and EDS suggest the presence of strain in the shortest inserts. This capability to control the formation of axial nanopillar heterostructures is crucial for optimized device integration.

Shapiro, J. N.; Lin, A.; Wong, P. S.; Scofield, A. C.; Tu, C.; Senanayake, P. N.; Mariani, G.; Liang, B. L.; Huffaker, D. L. [Department of Electrical Engineering and California Nano-Systems Institute, University of California at Los Angeles, Los Angeles, California 90095 (United States)

2010-12-13T23:59:59.000Z

222

Infrared spectroscopy of lattice vibrations in ZnTe/CdTe superlattices with quantum dots on the GaAs substrate with the ZnTe buffer layer  

SciTech Connect

The results of the analysis of the infrared lattice reflectance spectra of multiperiod ZnTe/CdTe superlattices with CdTe quantum dots are reported. The samples are grown by molecular beam epitaxy on the GaAs substrate with the ZnTe buffer layer. Due to the large number of periods of the superlattices, it is possible to observe CdTe-like vibration modes in the quantum dots, i.e., the dislocation-free stressed islands formed during the growth due to relaxation of elastic stresses between the ZnTe and CdTe layers are markedly different in their lattice parameters. From the frequency shifts of the CdTe- and ZnTe-like vibration modes with respect to the corresponding modes in the unstressed materials, it is possible to estimate the level of elastic stresses.

Kozyrev, S. P. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: skozyrev@sci.lebedev.ru

2009-03-15T23:59:59.000Z

223

Polarity driven simultaneous growth of free-standing and lateral GaAsP epitaxial nanowires on GaAs (001) substrate  

SciTech Connect

Simultaneous growth of ?111?{sub B} free-standing and ±[110] lateral GaAsP epitaxial nanowires on GaAs (001) substrates were observed and investigated by electron microscopy and crystallographic analysis. It was found that the growth of both free-standing and lateral ternary nanowires via Au catalysts was driven by the fact that Au catalysts prefer to maintain low-energy (111){sub B} interfaces with surrounding GaAs(P) materials: in the case of free-standing nanowires, Au catalysts maintain (111){sub B} interfaces with their underlying GaAsP nanowires; while in the case of lateral nanowires, each Au catalyst remain their side (111){sub B} interfaces with the surrounding GaAs(P) material during the lateral nanowire growth.

Sun, Wen; Xu, Hongyi [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia)] [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia); Guo, Yanan [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia) [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia); Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Gao, Qiang; Hoe Tan, Hark; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)] [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Zou, Jin, E-mail: j.zou@uq.edu.au [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia) [Materials Engineering, The University of Queensland, St Lucia QLD 40732 (Australia); Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia QLD 4072 (Australia)

2013-11-25T23:59:59.000Z

224

Importance of carrier dynamics and conservation of momentum in atom-selective STM imaging and band gap determination of GaAs(110)  

Science Journals Connector (OSTI)

Scanning tunneling microscopy and spectroscopy measurements on the GaAs(110) surface with complementary theoretical calculations are performed to clarify the effects involved in the tunneling of unpinned semiconductor surfaces. We show that the flatband and tip-induced band bending as well as equilibrium conditions are insufficient to describe the effects involved. Instead, carrier dynamics and conservation of momentum of the tunneling electrons need to be taken into account for a complete description of the contributions of the valence or conduction band states. The results allow us to understand the unique properties needed to achieve the atom-selective imaging observed on these surfaces as well as the determination of the band gap energy.

N. D. Jäger, E. R. Weber, K. Urban, and Ph. Ebert

2003-04-29T23:59:59.000Z

225

but the resolution of 2 was not sufficient to determine whether the C18  

E-Print Network (OSTI)

but the resolution of 2 was not sufficient to determine whether the C18 O emission was con- fined and AUI for funding the PT link project and to Western New Mexico Telephone Company for the use arsenide (GaAs) without losing their polar- ization, so that coherent transport through the active region

Thibado, Paul M.

226

Science and technology news Nanotechnology  

E-Print Network (OSTI)

method to make gallium arsenide solar cells May 20, 2010 by Lin Edwards Enlarge Image of a printed GaAs solar cell with a size ~10 x 10 mm2 on a glass substrate, with simple, metal grid contacts. Image light-sensitive semiconductors could make solar cells, night-vision cameras, and a range of other

Rogers, John A.

227

Home About UsContributeBookstore Advertising Subscribe for Free NOW!  

E-Print Network (OSTI)

.05As for the solar cells. The MESFET device membranes were transferred to glass substrates coated://www.semiconductor-today.com/news_items/2010/MAY/UOI_190510.htm #12;News 19 May 2010 Multi-story production of optoelectronics from Ga gallium arsenide (AlGaAs) layers on GaAs substrates using metal-organic chemical vapor deposition (MOCVD

Rogers, John A.

228

Study of structural properties of cubic InN films on GaAs(001) substrates by molecular beam epitaxy and migration enhanced epitaxy  

SciTech Connect

InN epitaxial films with cubic phase were grown by rf-plasma-assisted molecular beam epitaxy (RF-MBE) on GaAs(001) substrates employing two methods: migration-enhanced epitaxy (MEE) and conventional MBE technique. The films were synthesized at different growth temperatures ranging from 490 to 550 Degree-Sign C, and different In beam fluxes (BEP{sub In}) ranging from 5.9 Multiplication-Sign 10{sup -7} to 9.7 Multiplication-Sign 10{sup -7} Torr. We found the optimum conditions for the nucleation of the cubic phase of the InN using a buffer composed of several thin layers, according to reflection high-energy electron diffraction (RHEED) patterns. Crystallographic analysis by high resolution X-ray diffraction (HR-XRD) and RHEED confirmed the growth of c-InN by the two methods. We achieved with the MEE method a higher crystal quality and higher cubic phase purity. The ratio of cubic to hexagonal components in InN films was estimated from the ratio of the integrated X-ray diffraction intensities of the cubic (002) and hexagonal (1011) planes measured by X-ray reciprocal space mapping (RSM). For MEE samples, the cubic phase of InN increases employing higher In beam fluxes and higher growth temperatures. We have obtained a cubic purity phase of 96.4% for a film grown at 510 Degree-Sign C by MEE.

Casallas-Moreno, Y. L.; Perez-Caro, M.; Gallardo-Hernandez, S.; Ramirez-Lopez, M.; Martinez-Velis, I.; Lopez-Lopez, M. [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)] [Physics Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico); Escobosa-Echavarria, A. [Electric Engineering Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)] [Electric Engineering Department, Centro de Investigacion y de Estudios Avanzados del IPN, Apartado Postal 14-740, 07000 Mexico D.F. (Mexico)

2013-06-07T23:59:59.000Z

229

Imaging with Mass Spectrometry: A SIMS and VUV-Photoionization Study of Ion-Sputtered Atoms and Clusters from GaAs and Au  

SciTech Connect

A new mass spectrometry surface imaging method is presented in which ion-sputtered neutrals are postionized by wavelength-tunable vacuum ultraviolet (VUV) light from a synchrotron source. Mass spectra and signal counts of the photoionized neutrals from GaAs (100) and Au are compared to those of the secondary ions. While clusters larger than dimers are more efficiently detected as secondary ions, certain species, such as As2, Au and Au2, are more efficiently detected through the neutral channel. Continuously tuning the photon wavelength allows photoionization efficiency (PIE) curves to be obtained for sputtered Asm (m=1,2) and Aun (n=1-4). From the observed ionization thresholds, sputtered neutral As and Au show no clear evidence of electronic excitation, while neutral clusters have photoionization onsets shifted to lower energies by ~;;0.3 eV. These shifts are attributed to unresolved vibrational and rotational excitations. High-spatial resolution chemical imaging with synchrotron VUV postionization is demonstrated at two different photon energies using a copper TEM grid embedded in indium. The resulting images are used to illustrate the use of tunable VUV light for verifying mass peak assignments by exploiting the unique wavelength-dependent PIE of each sputtered neutral species. This capability is valuable for identifying compounds when imaging chemically complex systems with mass spectrometry-based techniques.

Takahashi, Lynelle; Zhou, Jia; Wilson, Kevin R.; Leone, Stephen R.; Ahmed, Musahid

2008-12-05T23:59:59.000Z

230

Relation between the metastability of EL2 and the photosensitivity of local vibrational modes in semi-insulating GaAs  

Science Journals Connector (OSTI)

Recent infrared spectroscpic observations of local vibrational mode absorptions have revealed a number of photosensitive centers in semi-insulating GaAs. They include (OVAs) center which has three modes at 730 cm-1 (A), 715 cm-1 (B), and 714 cm-1 (C), respectively, a suggested NH center related to a line at 983 cm-1 (X1), and centers related to hydrogen, such as (H-O) or (H-N) bonds, corresponding to a group of peaks in the region of 2900–3500 cm-1. The photosensitivity of various local vibration centers was observed to have similar time dependence under near-infrared illumination and was suggested to be due to their charge-state interconversion. Mainly described in this work is the effect of the 1.25-eV illumination. It is confirmed that this photoinduced kinetic process results from both electron capture and hole capture, which are closely related to the photoionization behavior and metastability of the EL2 center.

C. Y. Song, B. Pajot, W. K. Ge, and D. S. Jiang

1995-08-15T23:59:59.000Z

231

Wafer Bonding and Epitaxial Transfer of GaSb-based Epitaxy to GaAs for Monolithic Interconnection of Thermophotovoltaic Devices  

SciTech Connect

GaInAsSb/AlGaAsSb/InAsSb/GaSb epitaxial layers were bonded to semi-insulating GaAs handle wafers with SiO{sub x}/Ti/Au as the adhesion layer for monolithic interconnection of thermophotovoltaic (TPV) devices. Epitaxial transfer was completed by removal of the GaSb substrate, GaSb buffer, and InAsSb etch-stop layer by selective chemical etching. The SiO{sub x}/TiAu provides not only electrical isolation, but also high reflectivity and is used as an internal back-surface reflector. Characterization of wafer-bonded epitaxy by high-resolution x-ray diffraction and time-decay photoluminescence indicates minimal residual stress and enhancement in optical quality. 0.54-eV GaInAsSb cells were fabricated and monolithically interconnected in series. A 10-junction device exhibited linear voltage building with an open-circuit voltage of 1.8 V.

C.A. Wang; D.A. Shiau; P.G. Murphy; P.W. O'brien; R.K. Huang; M.K. Connors; A.C. Anderson; D. Donetsky; S. Anikeev; G. Belenky; D.M. Depoy; G. Nichols

2003-06-16T23:59:59.000Z

232

Sputtering of Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN by electrosprayed nanodroplets  

SciTech Connect

This article presents a characterization of the damage caused by energetic beams of electrosprayed nanodroplets striking the surfaces of single-crystal semiconductors including Si, SiC, InAs, InP, Ge, GaAs, GaSb, and GaN. The sputtering yield (number of atoms ejected per projectile's molecule), sputtering rate, and surface roughness are measured as functions of the beam acceleration potential. The maximum values of the sputtering yields range between 1.9 and 2.2 for the technological important but difficult to etch SiC and GaN respectively, and 4.5 for Ge. The maximum sputtering rates for the non-optimized beam flux conditions used in our experiments vary between 409?nm/min for SiC and 2381?nm/min for GaSb. The maximum sputtering rate for GaN is 630?nm/min. Surface roughness increases modestly with acceleration voltage, staying within 2?nm and 20?nm for all beamlet acceleration potentials and materials except Si. At intermediate acceleration potentials, the surface of Si is formed by craters orders of magnitude larger than the projectiles, yielding surface roughness in excess of 60?nm. The effect of projectile dose is studied in the case of Si. This parameter is correlated with the formation of the large craters typical of Si, which suggests that the accumulation of damage following consecutive impacts plays an important role in the interaction between beamlet and target.

Borrajo-Pelaez, Rafael; Grustan-Gutierrez, Enric; Gamero-Castaño, Manuel, E-mail: mgameroc@uci.edu [Department of Mechanical and Aerospace Engineering, University of California, Irvine, California 92697 (United States)

2013-11-14T23:59:59.000Z

233

Structural and band alignment properties of Al{sub 2}O{sub 3} on epitaxial Ge grown on (100), (110), and (111)A GaAs substrates by molecular beam epitaxy  

SciTech Connect

Structural and band alignment properties of atomic layer Al{sub 2}O{sub 3} oxide film deposited on crystallographically oriented epitaxial Ge grown in-situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers were investigated using cross-sectional transmission microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). High-resolution triple axis x-ray measurement demonstrated pseudomorphic and high-quality Ge epitaxial layer on crystallographically oriented GaAs substrates. The cross-sectional TEM exhibited a sharp interface between the Ge epilayer and each orientation of the GaAs substrate as well as the Al{sub 2}O{sub 3} film and the Ge epilayer. The extracted valence band offset, {Delta}E{sub v}, values of Al{sub 2}O{sub 3} relative to (100), (110), and (111) Ge orientations using XPS measurement were 3.17 eV, 3.34 eV, and 3.10 eV, respectively. Using XPS data, variations in {Delta}E{sub v} related to the crystallographic orientation were {Delta}E{sub V}(110)Ge>{Delta}E{sub V}(100)Ge{>=}{Delta}E{sub V}(111)Ge and the conduction band offset, {Delta}E{sub c}, related to the crystallographic orientation was {Delta}E{sub c}(111)Ge>{Delta}E{sub c}(110)Ge>{Delta}E{sub c}(100)Ge using the measured {Delta}E{sub v}, bandgap of Al{sub 2}O{sub 3} in each orientation, and well-known Ge bandgap of 0.67 eV. These band offset parameters are important for future application of Ge-based p- and n-channel metal-oxide field-effect transistor design.

Hudait, M. K.; Zhu, Y. [Advanced Devices and Sustainable Energy Laboratory (ADSEL), Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Patra, P. K. [Department of Biomedical Engineering and Department of Mechanical Engineering, University of Bridgeport, Bridgeport, Connecticut 06604 (United States); Ma, A. W. K. [Department of Chemical and Biomolecular Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Aphale, A.; Macwan, I. [Department of Electrical and Computer Engineering, University of Bridgeport, Bridgeport, Connecticut 06604 (United States)

2013-04-07T23:59:59.000Z

234

Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers  

SciTech Connect

Beryllium-doped GaAs layers grown at low temperatures by molecular-beam epitaxy contain localized spins associated with unpaired sp electrons of As{sub Ga}{sup +} ions. Interactions of these localized spins are investigated by measuring the magnetization with a superconducting quantum interference device and the peak-to-peak width of electron paramagnetic resonance (EPR) spectra for samples with different spin concentrations ranging from 3 x 10{sup 18} to 2.0 x 10{sup 19} cm{sup -3}. The results show that localized spins in this material antiferromagnetically interact on each other via direct exchange. From the analysis of the temperature dependence and field dependence of the magnetization on the basis of the Curie-Weiss law and the molecular-field approximation, exchange energy of each sample was derived. The dependence of the exchange energy on the concentration of localized spins is reasonably explained by a model of direct exchange, which results from the overlapping of wave functions of unpaired electrons at As{sub Ga}{sup +} ions. The peak-to-peak width of EPR spectra increases with an increase in the spin concentration at low temperatures, whereas it decreases with an increase in the temperature for samples with high spin concentrations. These EPR results also show that significant exchange interactions indeed occur between localized spins in this material. These effects of direct exchange interactions between localized spins can clearly be observed at their average distances of around 4 nm, which implies a considerably large spatial extension of the wave function of an unpaired sp electron around an As{sub Ga}{sup +} ion.

Bae, K. W.; Mohamed, Mohd Ambri; Jung, D. W.; Otsuka, N. [School of Materials Science Japan Advanced Institute of Science and Technology Asahidai 1-1, Nomishi, Ishikawa 923-1292 (Japan)

2011-04-01T23:59:59.000Z

235

Structural ordering and interface morphology in symmetrically strained(GaIn)As/Ga(PAs) superlattices grown on off-oriented GaAs(100)  

Science Journals Connector (OSTI)

In this work we investigate the structural properties of symmetrically strained (GaIn)As/GaAs/Ga(PAs)/GaAs superlattices by means of x-ray diffraction, reciprocal-space mapping, and x-ray reflectivity. The multilayers were grown by metalorganic vapor-phase epitaxy on (001) GaAs substrates intentionally off-oriented towards one of the nearest ?110? directions. High-resolution triple-crystal reciprocal-space maps recorded for different azimuth angles in the vicinity of the (004) Bragg diffraction clearly show a double periodicity of the x-ray peak intensity that can be ascribed to a lateral and a vertical periodicity occurring parallel and perpendicular to the growth surface. Moreover, from the intensity modulation of the satellite peaks, a lateral-strain gradient within the epilayer unit cell is found, varying from a tensile to a compressive strain. Thus, the substrate off-orientation promotes a lateral modulation of the layer thickness (ordered interface roughness) and of the lattice strain, giving rise to laterally ordered macrosteps. In this respect, contour maps of the specular reflected beam in the vicinity of the (000) reciprocal lattice point were recorded in order to inspect the vertical and lateral interface roughness correlation. A semiquantitative analysis of our results shows that the interface morphology and roughness is greatly influenced by the off-orientation angle and the lateral strain distribution. Two mean spatial wavelengths can be determined, one corresponding exactly to the macrostep periodicity and the other indicating a further interface waviness along the macrosteps. The same spatial periodicities were found on the surface by atomic-force-microscopy images confirming the x-ray results and revealing a strong vertical correlation of the interfaces up to the outer surface.

C. Giannini; L. Tapfer; Y. Zhuang; L. De Caro; T. Marschner; W. Stolz

1997-02-15T23:59:59.000Z

236

IR spectroscopy of lattice vibrations and comparative analysis of the ZnTe/CdTe quantum-dot superlattices on the GaAs substrate and with the ZnTe and CdTe buffer layers  

SciTech Connect

A comparative analysis of multiperiod ZnTe/CdTe superlattices with the CdTe quantum dots grown by molecular beam epitaxy on the GaAs substrate with the ZnTe and CdTe buffer layers is carried out. The elastic-stress-induced shifts of eigenfrequencies of the modes of the CdTe- and ZnTe-like vibrations of materials forming similar superlattices but grown on different buffer ZnTe and CdTe layers are compared. The conditions of formation of quantum dots in the ZnTe/CdTe superlattices on the ZnTe and CdTe buffer layers differ radically.

Kozyrev, S. P. [Russian Academy of Sciences, Lebedev Institute of Physics (Russian Federation)], E-mail: skozyrev@sci.lebedev.ru

2009-07-15T23:59:59.000Z

237

RELATIVE ATTENUATION CHARACTERISTICS OF SOME SHIELDING MATERIALS FOR PuB NEUTRONS  

E-Print Network (OSTI)

1: Polyethylene Water Spodumene-gypsum Gypsum, wet and dryconstituents of the spodumene-gypsum, and gypsum shields.SPODUMENK·,GYPSUM SHIELD 30% Spodumene by weight 40% Gypsum

Bringham, P.S.

2010-01-01T23:59:59.000Z

238

Electronic parameters and interfacial properties of GaAs/AlxGa1-xAs multiquantum wells grown on (111)A GaAs by metalorganic vapor phase epitaxy  

Science Journals Connector (OSTI)

We report a comprehensive study of the optical and interfacial properties of GaAs/AlxGa1-xAs multiquantum wells grown on (111)A GaAs substrates by metalorganic vapor phase epitaxy which allowed the determination of the electronic parameters appropriate for such quantum wells. High-resolution x-ray diffractometry studies indicate an excellent crystal quality and good periodicity for the multiquantum wells and provided their structural parameters accurately. The photoreflectance spectra exhibit all the allowed and almost all the weakly allowed optical transitions between the confined hole and electron states. From an analysis of the photoreflectance spectra it is shown that the quantum well interfaces have an abruptness better than ±1 ML. Photoluminescence spectroscopy was also performed to evaluate independently the roughness of the interfaces and multiquantum well period reproducibility. For a 25-period multiquantum well structure with a well width of 55 Å, a photoluminescence linewidth of 12.5 meV, which corresponds to a combined well-width fluctuation and interface roughness of less than ±1 monolayer over the 25 periods, proves the achievement of heterointerfaces with excellent interfacial quality. From a detailed analysis of the high-order transitions observed in the photoreflectance spectra we determined key quantum well electronic parameters, such as, the heavy-hole valence-band offset Qv=0.33±0.02, the transverse GaAs heavy-hole effective mass mhh=(0.95±0.02)m0, and the light-hole effective mass mlh=0.08m0 in ?111? directions, for ?111?-oriented GaAs/AlxGa1-xAs quantum well structures.

Soohaeng Cho; A. Sanz-Hervás; A. Majerfeld; B. W. Kim

2003-07-10T23:59:59.000Z

239

Fabrication of a gated gallium arsenide heterostructure resonant tunneling diode  

E-Print Network (OSTI)

metallization process ivas required because separate potentials must be apphed to the top and base ol' the defined mesas. A potent&al is apphed to the top of the mesas to inject carriers for tunneling through the douhle barrier heterostructures A. rectifying... was a demetal/degrease cleanup process which re- moved any contamination that may have been nn the wal'er. This process ivas followed by deposition of AuGe/Ni on the ivafer's backside which ivill provide an ohmic contact after annealing. The backside...

Kinard, William Brian

1989-01-01T23:59:59.000Z

240

Boron arsenide thin film solar cell development. Final report  

SciTech Connect

Pyrolytic decomposition of diborane and arsine has been used in attempts to grow polycrystalline BAs films. This method, however, produced only amorphous films for deposition temperatures below 920/sup 0/C and polycrystalline boron subarsenide (B/sub 12/As/sub 2/) flms for deposition temperatures above this value. The amorphous films have been determined to have a significant arsenic content but the actual stoichiometry was not obtained. The films were adherent on single crystal sapphire (0001), (111) silicon, (0001) SiC, and polycrystalline SiC but were found not to be adherent to substrates of fused quartz, tungsten, and molybdenum. It was also found that all films deposited above 650/sup 0/C were p-type while those deposited below 600/sup 0/C were usually n-type. Polycrystalline BAs and B/sub 12/As/sub 2/ was produced by reaction of the elements in a closed tube. The amorphous films showed an indirect or non-direct optical bandgap from 1.0 to 1.7 eV with the most probable values between 1.2 to 1.4 eV. The crystalline BAs powder shows a bandgap near 1.0 eV. Photoconductance time constants have been measured for films deposited on (0001) sapphire and (0001) SiC. Attempts at doping the amorphous films were generally unsuccessful. A polycrystalline powder sample was successfully doped with sulfur. Attempts were made to produce a Schottky barrier diode by evaporating Al dots onto an amorphous film on graphite without a post-evaporation anneal. An MIS structure was also attempted by baking an amorphous film in air at 280/sup 0/C before evaporation of aluminum. Although nonlinear characteristics were obtained, none of the devices showed any photovoltaic response. A p-type amorphous film was deposited on an n-type silicon substrate to form a p-n heterojunction. This device did exhibit a photovoltaic response but it is believed that the photogeneration was occurring primarily in the silicon substrate.

Boone, J.L.; Van Doren, T.P.

1980-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Transport in the quantum critical regime of the iron arsenide...  

NLE Websites -- All DOE Office Websites (Extended Search)

emerges, one whose thermodynamic and transport properties differ from the unified phenomenology with which we understand conventional metals - the Landau-Fermi liquid theory -...

242

Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum  

SciTech Connect

Frontier Geosciences (Frontier; FGS) proposed for DOE Grant No. DE-FG02-07ER84669 that mercury control could be achieved in a wet scrubber by the addition of an amendment to the wet-FGD scrubber. To demonstrate this, a bench-scale scrubber and synthetic flue-gas supply was designed to simulate the limestone fed, wet-desulfurization units utilized by coal-fired power plants. Frontier maintains that the mercury released from these utilities can be controlled and reduced by modifying the existing equipment at installations where wet flue-gas desulfurization (FGD) systems are employed. A key element of the proposal was FGS-PWN, a liquid-based mercury chelating agent, which can be employed as the amendment for removal of all mercury species which enter the wet-FGD scrubber. However, the equipment design presented in the proposal was inadequate to demonstrate these functions and no significant progress was made to substantiate these claims. As a result, funding for a Phase II continuation of this work will not be pursued. The key to implementing the technology as described in the proposal and report appears to be a high liquid-to-gas ratio (L/G) between the flue-gas and the scrubber liquor, a requirement not currently implemented in existing wet-FGD designs. It may be that this constraint can be reduced through parametric studies, but that was not apparent in this work. Unfortunately, the bench-scale system constructed for this project did not function as intended and the funds and time requested were exhausted before the separation studies could occur.

Hensman, Carl, E., P.h.D; Baker, Trevor

2008-06-16T23:59:59.000Z

243

Utilization of by-product gypsum in construction  

E-Print Network (OSTI)

as a by-product (called phosphogypsum) during acidulation of phosphate rock in the manufacture phosphoric acid. The sulfate is produced in either a dihydrate or a hemihydrate form depending on the operating conditions. Phosphogypsum produced... by Mobil Chemi- cal Company (Pasadena, Texas) is in the dihydrate form and was previously studied. Phosphogypsum produced by Occidental Chemical Company (White Springs, Florida), on the other hand, is produced in a hemihydrate form and transforms...

Stephenson, Angela Lorraine

2012-06-07T23:59:59.000Z

244

Gypsum and Polyacrylamide Soil Amendments Used With High Sodium Wastewater  

E-Print Network (OSTI)

Using wastewater for irrigation of crops represents an attractive alternative to disposal. Typically, municipal wastewaters are high in sodium, and the resulting high sodium absorption ratio (SAR) alters the soil structure making it more impermeable...

Gardiner, Duane

245

Evaluation of matrix elements of the 8×8 k?p Hamiltonian with k-dependent spin-orbit contributions for the zinc-blende structure of GaAs  

Science Journals Connector (OSTI)

The k?p method of band-structure calculation provides a detailed description of a crystal’s energy dispersion near a high symmetry point in the first Brillouin zone. The resulting parameters of this calculation are a series of momentum matrix elements. Presented here is a set of band-structure parameters for the zinc-blende structure of GaAs at the ? point that takes the lack of inversion symmetry into account as well as k-dependent spin-orbit contributions to the Hamiltonian. A comprehensive optimization was performed in order to satisfy effective mass data as well as conduction band spin-splitting data. It was found that the lack of inversion symmetry has a profound influence on the nonparabolicity of the conduction band and the contribution of the k-dependent spin-orbit effect cannot be ignored in the calculation of the effective mass of the conduction, light hole, and spin-orbit bands. © 1996 The American Physical Society.

T. E. Ostromek

1996-11-15T23:59:59.000Z

246

The influence of bond flexibility and molecular size on the chemically selective bonding of In 2 O and Ga 2 O on GaAs (001)-c(2×8)/(2×4)  

Science Journals Connector (OSTI)

The surface structures formed upon deposition of In 2 O and Ga 2 O by molecular beam epitaxy onto the arsenic-rich GaAs (001)-c(2×8)/(2×4) surface have been studied using scanning tunneling microscopy and density functional theory. In 2 O initially bonds with indium atoms bonding to second layer gallium atoms within the trough and proceeds to insert into or between first layer arsenic dimer pairs. In contrast Ga 2 O only inserts into or between arsenic dimer pairs due to chemical site constraints. The calculated energy needed to bend a Ga 2 O molecule approximately 70° so that it can fit into an arsenic dimer pair is 0.6 eV less than that required for In 2 O . The greater flexibility of the Ga 2 O molecule causes its insertion site to be 0.77 eV more exothermic than the In 2 O insertion site. This result shows that although trends in the periodic table can be used to predict some surface reactions small changes in atomic size can play a significant role in the chemistry of gas/surface reactions through the indirect effects of bond angle flexibility and bond length stiffness.

M. J. Hale; J. Z. Sexton; D. L. Winn; A. C. Kummel; M. Erbudak; M. Passlack

2004-01-01T23:59:59.000Z

247

Effect of spacer layer thickness on multi-stacked InGaAs quantum dots grown on GaAs (311)B substrate for application to intermediate band solar cells  

Science Journals Connector (OSTI)

We have investigated the properties of multi-stacked layers of self-organized In0.4Ga0.6As quantum dots(QDs) on GaAs (311)B grown by molecular beam epitaxy. We found that a high degree of in-plane ordering of QDs structure with a six-fold symmetry was maintained though the growth has been performed at a higher growth rate than the conventional conditions. The dependence of photoluminescence characteristics on spacer layer thickness showed an increasing degree of electronic coupling between the stacked QDs for thinner spacer layers. The external quantum efficiency for an InGaAs/GaAs quantum dotsolar cell (QDSC) with a thin spacer layer thickness increased in the longer wavelength range due to additive contribution from QD layers inserted in the intrinsic region. Furthermore a photocurrent production by 2-step photon absorption has been observed at room temperature for the InGaAs/GaAs QDSC with a spacer layer thickness of 15?nm.

Yasushi Shoji; Kohei Narahara; Hideharu Tanaka; Takashi Kita; Katsuhiro Akimoto; Yoshitaka Okada

2012-01-01T23:59:59.000Z

248

Impact of stress relaxation in GaAsSb cladding layers on quantum dot creation in InAs/GaAsSb structures grown on GaAs (001)  

SciTech Connect

We describe InAs quantum dot creation in InAs/GaAsSb barrier structures grown on GaAs (001) wafers by molecular beam epitaxy. The structures consist of 20-nm-thick GaAsSb barrier layers with Sb content of 8%, 13%, 15%, 16%, and 37% enclosing 2 monolayers of self-assembled InAs quantum dots. Transmission electron microscopy and X-ray diffraction results indicate the onset of relaxation of the GaAsSb layers at around 15% Sb content with intersected 60° dislocation semi-loops, and edge segments created within the volume of the epitaxial structures. 38% relaxation of initial elastic stress is seen for 37% Sb content, accompanied by the creation of a dense net of dislocations. The degradation of In surface migration by these dislocation trenches is so severe that quantum dot formation is completely suppressed. The results highlight the importance of understanding defect formation during stress relaxation for quantum dot structures particularly those with larger numbers of InAs quantum-dot layers, such as those proposed for realizing an intermediate band material.

Bremner, S. P. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052 (Australia)] [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney 2052 (Australia); Ban, K.-Y.; Faleev, N. N.; Honsberg, C. B. [School of Electrical, Computer and Energy Engineering, Ira A. Fulton Schools of Engineering, Solar Power Lab, Arizona State University, Tempe, Arizona 85287 (United States)] [School of Electrical, Computer and Energy Engineering, Ira A. Fulton Schools of Engineering, Solar Power Lab, Arizona State University, Tempe, Arizona 85287 (United States); Smith, D. J. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)] [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)

2013-09-14T23:59:59.000Z

249

Effects of crossed electric and magnetic fields on the electronic and excitonic states in bulk GaAs and GaAs?Ga1?xAlxAs quantum wells  

Science Journals Connector (OSTI)

The variational procedure in the effective-mass and parabolic-band approximations is used in order to investigate the effects of crossed electric and in-plane magnetic fields on the electronic and exciton properties in semiconductor heterostructures. Calculations are performed for bulk GaAs and GaAs?Ga1?xAlxAs quantum wells, for applied magnetic fields parallel to the layers and electric fields in the growth direction, and it is shown that the combined effects on the heterostructure properties of the applied crossed electric and magnetic fields and the direct coupling between the center-of-mass and internal exciton motions may be dealt with via a simple parameter representing the spatial distance between the centers of the electron and hole magnetic parabolas. Exciton properties are analyzed by using a simple hydrogenlike envelope excitonic wave function and present theoretical results are found in fair agreement with available experimental measurements on the diamagnetic shift of the photoluminescence peak position of GaAs?Ga1?xAlxAs quantum wells under in-plane magnetic fields.

M. de Dios-Leyva, C. A. Duque, and L. E. Oliveira

2007-01-02T23:59:59.000Z

250

Bates GaAs polarized electron source  

SciTech Connect

In order to pursue measurements of parity violating effects of the neutral weak current, we have developed a polarized electron source suitable for installation at the MIT-Bates Linear Accelerator. The source is designed to provide a high peak-current pulsed beam that has a approx. 1% duty factor and that is extremely stable under helicity reversal. 34 references, 6 figures, 1 table.

Schaefer, H.R.; Cates, G.; Michaels, R.; Hughes, V.W.. Lubell, M.S.; Souder, P.A.

1983-05-01T23:59:59.000Z

251

Argonne CNM Highlight: Superhydrophobicity on Silver Nanoplates  

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Superhydrophobicity on Silver Nanoplates Superhydrophobicity on Silver Nanoplates Superhydrophobic silver nanoplates Representations of water droplets on a GaAs substrate covered with the Ag nanoplates; as featured on back cover of the journal issue Gallium arsenide wafers decorated with silver nanoplates result in composite surfaces of varying hydrophobocity. CNM researchers and collaborators at Clemson have accomplished this in part by coating the silver nanoplates with self-assembled monolayers of alkyl thiol molecules. By carefully controlling reaction conditions, the size, thickness, and surface roughness of the individual silver nanoplates are tuned to produce different topographic structures and roughness of the composite surfaces. This in turn influences the surface hydrophobicity. The composite surfaces

252

Double dielectric passivation layer on InAs  

E-Print Network (OSTI)

-integration and fabrication difficulties of Josephson junctions appear to be insurmountable in the near future. This led to an increased interest in gallium arsenide (GaAs) devices like the high-electron mobility transistor (HEMT) and the modulation-doped field effect..., the thermodynamic stabilities of the A 0 and B 0 oxides, and the mutual solubilities of the oxides are of importance [10). Unfortunately neither the diffusion rates of the elements through the oxide nor the mutual solubilities of the oxides are known...

Egley, James Lee

2012-06-07T23:59:59.000Z

253

Assessment of the Passivation Capabilities of Two Different Covalent Chemical Modifications on GaP(100)  

Science Journals Connector (OSTI)

With respect to toxicity, the UDA-functionalized GaP provided better passivation which was confirmed by less gallium leaching into water and saline solutions. ... Due to its promising characteristics for device fabrication, gallium arsenide (GaAs) has been extensively studied and the formation of self-assembled monolayers has been of interest. ... A general increase in the Ga/P ratio can be seen in the surfaces exposed to solutions compared to the clean surface which is attributed to the greater solubility of the phosphorus oxide (P2O5) compared to the gallium oxide (Ga2O3). ...

David Richards; Dmitry Zemlyanov; Albena Ivanisevic

2010-02-03T23:59:59.000Z

254

Investigation of Gallium Partitioning Behavior in Aqueous Two-Phase Systems Containing Polyethylene Glycol and Ammonium Sulfate  

Science Journals Connector (OSTI)

Gallium is assumed to be an indispensable rare metal mainly because of its fast growing demand as gallium arsenide (GaAs) in integrated circuits. ... Traditional extraction methods for gallium usually are organic?water two-phase systems, which involve volatile, flammable, and explosive organic solvents, such as n-hexane, toluene, xylene, benzene, nitrobenzene and kerosene. ... (17) A temperature increase reduces the mutual solubility of the two phases and results in an increase of PEG concentration in the upper phase and of volume in the lower phase, which all make ?w1 increase. ...

Yuhuan Chen; Xiaoli Liu; Yan Lu; Xiuying Zhang

2009-04-22T23:59:59.000Z

255

Water-Soluble Complexes from Random Copolymer and Oppositely Charged Surfactant. 2. Complexes of Poly(ethylene glycol)-Based Cationic Random Copolymer and Bile Salts  

Science Journals Connector (OSTI)

Water-Soluble Complexes from Random Copolymer and Oppositely Charged Surfactant. 2. Complexes of Poly(ethylene glycol)-Based Cationic Random Copolymer and Bile Salts ... Measurements of light scattering intensity were performed at room temperature (22 °C) on a multiangle light scattering detector (DAWN EOS fitted with a Wyatt QELS correlator (Wyatt Technology Corp.)), having a 30 mW (GaAs, gallium arsenide) laser emitting vertically polarized light at wavelength ? = 690 nm. ... Turbidimetric titration was used to determine the solubility of the polymer?surfactant complexes of various compositions. ...

C. K. Nisha; Sunkara V. Manorama; Jayachandran N. Kizhakkedathu; Souvik Maiti

2004-08-28T23:59:59.000Z

256

Water-Soluble Complexes from Random Copolymer and Oppositely Charged Surfactant. 1. Complexes of Poly(ethylene glycol)-Based Cationic Random Copolymer and Sodium Dodecyl Sulfate  

Science Journals Connector (OSTI)

Water-Soluble Complexes from Random Copolymer and Oppositely Charged Surfactant. 1. Complexes of Poly(ethylene glycol)-Based Cationic Random Copolymer and Sodium Dodecyl Sulfate ... Preliminary studies on the solubility of the complexes by turbidity measurements with one of the most studied anionic surfactants, sodium dodecyl sulfate (SDS), demonstrate that complexes of the polymer with 68 mol % PEG content are insoluble in water. ... (angles are measured with respect to the direction of the laser beam) equipped with a 30 mW (GaAs, gallium arsenide) laser emitting vertically polarized light at wavelength ? = 690 nm. ...

C. K. Nisha; Pratyay Basak; Sunkara V. Manorama; Souvik Maiti; Kizhakkedathu N. Jayachandran

2003-02-26T23:59:59.000Z

257

Fabrication of Semiconductors by Wet Chemical Etch  

E-Print Network (OSTI)

Arsenide. New York: John Wiley & Sons, Inc, 1994. CONCLUSIONS AND FUTURE WORK A selective wet etch process to re- move GaAs epitaxial cap layers from underlying InGaP layers has been de- veloped using a solution of H2SO4: H2O2:deionized water at a rate... the computing and electronics industries. Semiconducting materials, such as silicon, germanium, gallium ar- senide, and indium phosphide, are neither good insulators nor good con- ductors, but they have intrinsic electri- cal properties so that by controlled...

Francoviglia, Laura

2008-07-01T23:59:59.000Z

258

Synthesis and Characterization of Bulk Vitreous Cadmium Germanium...  

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Bulk Vitreous Cadmium Germanium Arsenide. Synthesis and Characterization of Bulk Vitreous Cadmium Germanium Arsenide. Abstract: Abstract Cadmium-germanium-diarsenide...

259

Plasmonic Light Trapping in an Ultrathin Photovoltaic Layer with Film-Coupled Metamaterial Structures  

E-Print Network (OSTI)

A film-coupled metamaterial structure is numerically investigated for enhancing the light absorption in an ultrathin photovoltaic layer of crystalline gallium arsenide (GaAs). The top subwavelength concave grating and the bottom metallic film could not only effectively trap light with the help of wave interference and magnetic resonance effects excited above the bandgap, but also practically serve as electrical contacts for photon-generated charge collection. The energy absorbed by the active layer is greatly enhanced in the film-coupled metamaterial structure, resulting in significant enhancement on the short-circuit current density by three times over a free-standing GaAs layer at the same thickness. The results would facilitate the development of next-generation ultrathin solar cells with lower cost and higher efficiency.

Wang, Hao

2014-01-01T23:59:59.000Z

260

Development of indium arsenide quantum dot solar cells for high conversion efficiency.  

E-Print Network (OSTI)

??Sunlight is the largest energy source available on earth. Under clear conditions there is approximately 1,000 watts per directly incident square meter, which reaches the… (more)

El-Emawy, Mohamed

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

E-Print Network 3.0 - arsenide x-ray imaging Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

Electrons suffer from significant... collimated beams of X-rays (usually from a synchroton or storage ring). This has the advantage of producing... , proton-beam writing...

262

Magnetism and superconductivi[t]y in Pr-based filled skutterudite arsenides  

E-Print Network (OSTI)

5.11: Zero ?eld electrical resistivity vs temperature ?(T )technique. The electrical resistivity ? vs temperature T5.3: The zero-?eld electrical resistivity ? vs temperature T

Sayles, Todd Allen

2008-01-01T23:59:59.000Z

263

PROCESSING ISSUES IN THE DEVELOPMENT OF INDIUM-ARSENIDE-BASE HETEROJUNCTION BIPOLAR TRANSISTORS  

E-Print Network (OSTI)

, the forward plasma power was kept at $100 W with 5.0 sccm CF4 plus 10.0 sccm Ar gas flow. The dry etching rate

264

E-Print Network 3.0 - arsenide integrated circuit Sample Search...  

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-3:40pm Summary: 02139 A novel epitaxy-on-electronics process for fabricating optoelectronic integrated circuits (OE- ICs... integrated circuit technology base, this...

265

E-Print Network 3.0 - arsenide gallium nitride Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

An advanced diffusion model to identify emergent research issues: the case of optoelectronic devices Summary: instrumentation Absorption coefficients Aluminium Nitrides Aluminium...

266

E-Print Network 3.0 - arsenide p-i-n detectors Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Sciences ; Engineering 52 header for SPIE use Integrated cooling for optoelectronic devices Summary: from similar materials. Experimental analysis of an InP p-i-n diode...

267

E-Print Network 3.0 - arsenide inas quantum Sample Search Results  

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Nanometer-scale islands that form spontaneously on a semiconductor... and optoelectronic devices, quantum computing, and History, information storage. Highlights, ... Source:...

268

E-Print Network 3.0 - arsenide junction-field-effect transistors...  

NLE Websites -- All DOE Office Websites (Extended Search)

Texas at Arlington Materials Science and Engineering Department Summary: and optoelectronic devices. Topics include electrical properties of semiconductors, p-n junctions,...

269

Magnetism and superconductivi[t]y in Pr-based filled skutterudite arsenides  

E-Print Network (OSTI)

in the conduction band The Josephson junction . . . . . .1.4: A diagram of a Josephson junction, consisting of tworings joined by two Josephson junctions. The current through

Sayles, Todd Allen

2008-01-01T23:59:59.000Z

270

Fabrication of an optically driven 10 GHz ring resonator on a gallium arsenide substrate  

E-Print Network (OSTI)

/D converters, optical detectors, dc to rf converters, and millimeter-wave or microwave generators. Photoconductors can be easily integrated with microelectronic devices as well as microwave circuits. Recently, an optically excited photoconductive switch... is the barrier height and y, is the electron affinity for the semiconductor. Current flow at a metal-semiconductor barrier is due mainly to majority carriers. The four major current transport methods are thermionic emission over the barrier, quantum...

McGregor, Douglas Scott

1989-01-01T23:59:59.000Z

271

Magnetism and superconductivi[t]y in Pr-based filled skutterudite arsenides  

E-Print Network (OSTI)

1.3 Magnetism . . . . .1.3.3 Itinerant Magnetism . . . . . . . . . . .3.3 Magnetism . . . . . . . . . . . . . . . . . . . . . 3.4

Sayles, Todd Allen

2008-01-01T23:59:59.000Z

272

Process development for the fabrication of monolithic optoelectronic resonators on gallium arsenide substrates  

E-Print Network (OSTI)

of greater solubility wash away. The wafers were immersed in a diluted MF312 developer snd slightly agitated. When development was completed, the wafers were rinsed with deionized (DI) water and blown dry. Hard baking in a low pressure chamber removes any... of greater solubility wash away. The wafers were immersed in a diluted MF312 developer snd slightly agitated. When development was completed, the wafers were rinsed with deionized (DI) water and blown dry. Hard baking in a low pressure chamber removes any...

Fairchild, Brock Wilson

2012-06-07T23:59:59.000Z

273

E-Print Network 3.0 - arsenide photoconductive detectors Sample...  

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7 Terahertz emission from black silicon M. Theuer,2 Summary: -called photoconductive terahertz emitters and detectors, radiation-damaged silicon on sapphire or low-...

274

E-Print Network 3.0 - arsenide single crystals Sample Search...  

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Technion, Israel Institute of Technology Collection: Engineering ; Materials Science 73 Tunable narrow-bandwidth source of THz radiation based on frequency down-conversion in...

275

Magnetism and superconductivi[t]y in Pr-based filled skutterudite arsenides  

E-Print Network (OSTI)

H. J. Kang, J. W. Lynn, Pengcheng Dai, S. K. McCall, M. W.H. J. Kang, J. W. Lynn, Pengcheng Dai, S. K. McCall, M. W.H. J. Kang, J. W. Lynn, Pengcheng Dai, S. K. McCall, M. W.

Sayles, Todd Allen

2008-01-01T23:59:59.000Z

276

Remediation of brine-contaminated soil using calcium nitrate, gypsum, and straw.  

E-Print Network (OSTI)

??Salt-affected soils from point source brine contamination are common in the active oil field in SE Saskatchewan. A remediation process that included dewatering by sub-surface… (more)

Nielsen, Jennifer I.

2013-01-01T23:59:59.000Z

277

Holographic interferometry study of the dissolution and diffusion of gypsum in Jean Colombani  

E-Print Network (OSTI)

and Wilde, 1971) with a Nernst-Hartley equation from the tracer diffusivity of the ions (Jeschke et al

Paris-Sud XI, Université de

278

Lago Verde and Lago Flaco: Gypsum-bound lakes of the Chilean ...  

Science Journals Connector (OSTI)

Oct 16, 1975 ... ceed 20°C. (For 15 December 1972 mini- mum and maximum temperatures were about 5” and 24°C for air, and 11” and. 18°C for the lake. ) ...

2000-01-04T23:59:59.000Z

279

The detrimental effects of salinity on rooting of coleus cuttings and their alleviation with gypsum  

E-Print Network (OSTI)

. The effect of NaC1 on root number and color intensity of the foliage were not altered by the addition of CaSO . The beneficial effects of CaS04 cou1d not be demonstrated in a peat-styrafoam medium. Acknowledgements I would like to express my sincere... Ca/Na ratios for the NaC1:Ca504 solutions 5 Electrical conductivities (E. C. ) of 2 KNO solutions with i ncreasing CaS04 concent/ations 6 The effects of pH and peat extract on rooting of 'Big Red' cuttings . Page 13 15 44 45 56 LIST...

Janssen, Antonius Hendrick

2012-06-07T23:59:59.000Z

280

Diffusion of small solutes in polymer-containing solutions  

Science Journals Connector (OSTI)

...Arsinogallane and Chemical Conversion to Gallium Arsenide ERIN K. BYRNE, LASZLO PARKANYI...yield the rn-V semiconductor gallium arsenide as a finely divided amorphous...the reaction small dusters of gallium arsenide were apparently present in solution...

KL Yam; DK Anderson; RE Buxbaum

1988-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Building Stones  

E-Print Network (OSTI)

known as “burnt gypsum” or “plaster of Paris. ” When mixedsolid material. Such “gypsum plaster” was produced from lateand painted. Gypsum plaster was also sometimes employed as a

2012-01-01T23:59:59.000Z

282

Soil Formation and Transport Processes on Hillslopes along a Precipitation Gradient in the Atacama Desert, Chile  

E-Print Network (OSTI)

2006). Gypsum, anhydrite, halite, carbonate, iodate andbedrock contain gypsum and halite, but show little evidence2006). Gypsum, anhydrite, halite, carbonate, iodate and

Owen, Justine J.

2009-01-01T23:59:59.000Z

283

Liquid phase epitaxial growth of GaAs  

SciTech Connect

Research into new semiconductor materials for measurement of electromagnetic radiation over a wide range of energies has been an active field for several decades. There is a strong desire to identify and develop new materials which can lead to improved detectors. Such devices are expected to solve problems that cannot be solved using the semiconductor materials and device structures which have been traditionally used for radiation detection. In order for a detector which is subjected to some type of irradiation to respond, the radiation must undergo an interaction with the detector. The net result of the radiation interaction in a broad category of detectors is the generation of mobile electric charge carriers (electrons and/or holes) within the detector active volume. This charge is collected at the detector contacts and it forms the basic electrical signal. Typically, the collection of the charge is accomplished through the imposition of an electric field within the detector which causes the positive and/or negative charges created by the radiation to flow in opposite directions to the contacts. For the material to serve as a good radiation detector, a large fraction (preferably 100%) of all carriers created by the interacting incident radiation must be collected. Charge trapping by deep level impurities and structural defects can seriously degrade detector performance. The focus of this thesis is on far infrared and X-ray detection. In X-ray detector applications of p-I-n diodes, the object is to measure accurately the energy distribution of the incident radiation quanta. One important property of such detectors is their ability to measure the energy of individual incident photons with high energy resolution.

Wynne, D.I. [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering; [Lawrence Berkeley National Lab., CA (United States)

1997-10-01T23:59:59.000Z

284

Spire Semiconductor formerly Bandwidth Semiconductor LLC | Open Energy  

Open Energy Info (EERE)

Semiconductor formerly Bandwidth Semiconductor LLC Semiconductor formerly Bandwidth Semiconductor LLC Jump to: navigation, search Name Spire Semiconductor (formerly Bandwidth Semiconductor LLC) Place Hudson, New Hampshire Zip 3051 Product Spire-owned US-based manufacturer of gallium-arsenide (GaAs) cells; offers design and manufacturing capabilities of concentrator cells. References Spire Semiconductor (formerly Bandwidth Semiconductor LLC)[1] LinkedIn Connections CrunchBase Profile No CrunchBase profile. Create one now! This article is a stub. You can help OpenEI by expanding it. Spire Semiconductor (formerly Bandwidth Semiconductor LLC) is a company located in Hudson, New Hampshire . References ↑ "Spire Semiconductor (formerly Bandwidth Semiconductor LLC)" Retrieved from "http://en.openei.org/w/index.php?title=Spire_Semiconductor_formerly_Bandwidth_Semiconductor_LLC&oldid=351621"

285

Beyond Silicon: Cutting the Costs of Solar Power | U.S. DOE Office of Science (SC)  

NLE Websites -- All DOE Office Websites (Extended Search)

Beyond Silicon: Cutting the Costs of Solar Power Beyond Silicon: Cutting the Costs of Solar Power Stories of Discovery & Innovation Beyond Silicon: Cutting the Costs of Solar Power Enlarge Photo Courtesy of University of Illinois Mechanically flexible, high efficiency solar module that uses an interconnected array of microscale GaAs photovoltaic cells, grown in a multilayer stack on a wafer and then printed onto a sheet of plastic. Enlarge Photo 04.15.11 Beyond Silicon: Cutting the Costs of Solar Power New method of fabricating semiconductors from gallium arsenide promises more affordable solar power, improved semiconductor devices. The biggest single barrier to widespread adoption of solar power continues to be the cost of solar cells. University of Illinois materials scientists supported by the DOE Office of Science have scored a

286

X-ray induced optical reflectivity  

The change in optical reflectivity induced by intense x-ray pulses can now be used to study ultrafast many body responses in solids in the femtosecond time domain. X-ray absorption creates photoelectrons and core level holes subsequently filled by Auger or fluorescence processes, and these excitations ultimately add conduction and valence band carriers that perturb optical reflectivity.Optical absorption associated with band filling and band gap narrowing is shown to explain the basic features found in recent measurements on an insulator (silicon nitride, Si3N4), a semiconductor(gallium arsenide,GaAs), and a metal (gold,Au), obtained with ?100 fs x-ray pulses at 500-2000 eV and probed with 800 nm laser pulses. In particular GaAs exhibits an abrupt drop in reflectivity, persisting only for a time comparable to the x-ray excitation pulse duration, consistent with prompt band gap narrowing.

Durbin, Stephen M.

2012-01-01T23:59:59.000Z

287

Micro-cooler enhancements by barrier interface analysis  

SciTech Connect

A novel gallium arsenide (GaAs) based micro-cooler design, previously analysed both experimentally and by an analytical Heat Transfer (HT) model, has been simulated using a self-consistent Ensemble Monte Carlo (EMC) model for a more in depth analysis of the thermionic cooling in the device. The best fit to the experimental data was found and was used in conjunction with the HT model to estimate the cooler-contact resistance. The cooling results from EMC indicated that the cooling power of the device is highly dependent on the charge distribution across the leading interface. Alteration of this charge distribution via interface extensions on the nanometre scale has shown to produce significant changes in cooler performance.

Stephen, A.; Dunn, G. M. [Department of Physics, University of Aberdeen, King's College, AB24 3UE Aberdeen (United Kingdom)] [Department of Physics, University of Aberdeen, King's College, AB24 3UE Aberdeen (United Kingdom); Glover, J.; Oxley, C. H. [Department of Engineering, De Montfort University, Gateway, LE1 9BH Leicester (United Kingdom)] [Department of Engineering, De Montfort University, Gateway, LE1 9BH Leicester (United Kingdom); Bajo, M. Montes; Kuball, M. [Center for Device Thermography and Reliability, H. H. Wills Physics Laboratory, University of Bristol, BS8 1TL Bristol (United Kingdom)] [Center for Device Thermography and Reliability, H. H. Wills Physics Laboratory, University of Bristol, BS8 1TL Bristol (United Kingdom); Cumming, D. R. S.; Khalid, A. [School of Engineering, University of Glasgow, Rankine Building, G12 8LT Glasgow (United Kingdom)] [School of Engineering, University of Glasgow, Rankine Building, G12 8LT Glasgow (United Kingdom)

2014-02-15T23:59:59.000Z

288

Thermo-Induced Self-Assembly of Responsive Poly(DMAEMA-b-DEGMA) Block Copolymers into Multi- and Unilamellar Vesicles  

Science Journals Connector (OSTI)

LCST polymers are soluble below a certain temperature because of the formation of hydrogen bonds between water molecules of the hydration shell and the polymer chains. ... Size-exclusion chromatography (SEC) was performed on a system comprising a Waters 590 HPLC pump and a Waters 410 refractive index detector equipped with three Waters Styragel columns (HT2, HT3, HT4, each 300 mm × 7.8 mm, providing an effective molar mass range of 100–600000 g mol–1). ... High-throughput dynamic light scattering (HT-DLS) measurements were performed on the DynaPro Plate Reader Plus (Wyatt Technology Corporation, Santa Barbara, CA) equipped with a 60 mV linearly polarized gallium arsenide (GaAs) laser of ? = 832.5 nm and operating at an angle of 156°. ...

Christian Pietsch; Ulrich Mansfeld; Carlos Guerrero-Sanchez; Stephanie Hoeppener; Antje Vollrath; Michael Wagner; Richard Hoogenboom; Simon Saubern; San H. Thang; C. Remzi Becer; John Chiefari; Ulrich S. Schubert

2012-11-19T23:59:59.000Z

289

High-efficiency solar cell and method for fabrication  

DOE Patents (OSTI)

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).

Hou, Hong Q. (Albuquerque, NM); Reinhardt, Kitt C. (Albuquerque, NM)

1999-01-01T23:59:59.000Z

290

High-efficiency solar cell and method for fabrication  

DOE Patents (OSTI)

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.

Hou, H.Q.; Reinhardt, K.C.

1999-08-31T23:59:59.000Z

291

Journal of Engineering Physics and Thermophysics, VoL 71, No..5, 1998 SIMULATION OF A GALLIUM ARSENIDE RUNNING  

E-Print Network (OSTI)

and investigating HHT devices containing active elements with distributed parameters. Nowadays an active search structure of one or another configuration and a cathode section in the form of a Schottky barrier whose of Materials of Electronic Technology, Warsaw; Institute of Physics and Technology, National Academy

Harilal, S. S.

292

Weathering of cobalt arsenides: Natural assemblages and calculated stability relations among secondary Ca-Mg-Co arsenates and carbonates  

Science Journals Connector (OSTI)

...Sainfeldite Ca5(AsO3OH)2(AsO4)24 H2O Talmessite Ca2Mg(AsO4)22 H2O Vladimirite Ca5...hornesite [3] M, J Picropharmacolite + talmessite [4], [7] M, R Picropharmacolite...significant amounts of Co compared to talmessite. Paragenetic relationships The observed...

Gregor Markl; Michael A.W. Marks; Insa Derrey; Jan-Erik Gühring

293

Modeling of coupled heat transfer and reactive transport processes in porous media: Application to seepage studies at Yucca Mountain, Nevad a  

E-Print Network (OSTI)

of gypsum (or anhydrite), halite, fluorite and other salts.such as anhydrite, gypsum, or halite) also precipitate as a

Mukhopadhyay, Sumit; Sonnenthal, Eric L.; Spycher, Nicolas

2008-01-01T23:59:59.000Z

294

On nonlinear inverse problems of heat transfer with radiation boundary conditions. Application to dehydratation of gypsum plasterboards exposed to fire  

E-Print Network (OSTI)

resistance. Such materials must provide a sufficient mechanical resistance to avoid the prema- ture collapse the fire resistance of materials are given by several norms which define the minimum fire exposure duration that must support the building structure. One of the building materials presenting the best fire resistance

Paris-Sud XI, Université de

295

Gypsum scale formation on a heated copper plate under natural convection conditions and produced water remediation technologies review .  

E-Print Network (OSTI)

??Scaling or crystallization fouling of unwanted salts is one of the most challenging and expensive problems encountered in different applications such as heat exchangers and… (more)

Mirhi, Mohamad H. (Mohamad Hussein)

2013-01-01T23:59:59.000Z

296

3D geological modelling at urban scale and mapping of ground movement susceptibility from gypsum dissolution: the Paris example (France)  

E-Print Network (OSTI)

, the Inspection Générale des Carrières (IGC; General Inspectorate of Quarries) has the task of managing the risks

Boyer, Edmond

297

Lattice distortions in layered type arsenides LnTAs{sub 2} (Ln=La-Nd, Sm, Gd, Tb; T=Ag, Au): Crystal structures, electronic and magnetic properties  

SciTech Connect

The lanthanide coinage-metal diarsenides LnTAs{sub 2} (Ln=La, Ce-Nd, Sm; T=Ag, Au) have been reinvestigated and their structures have been refined from single crystal X-ray data. Two different distortion variants of the HfCuSi{sub 2} type are found: PrAgAs{sub 2}, NdAgAs{sub 2}, SmAgAs{sub 2}, GdAgAs{sub 2}, TbAgAs{sub 2}, NdAuAs{sub 2} and SmAuAs{sub 2} crystallize as twofold superstructures in space group Pmcn with the As atoms of their planar layers forming zigzag chains, whereas LaAgAs{sub 2}, CeAgAs{sub 2} and PrAuAs{sub 2} adopt a fourfold superstructure (space group Pmca) with cis-trans chains of As atoms. The respective atomic positions can be derived from the HfCuSi{sub 2} type by group-subgroup relations. The compounds with zigzag chains of As atoms exhibit metallic behaviour while those with cis-trans chains are semiconducting as measured on powder pellets. The majority of the compounds including 4f elements show antiferromagnetic ordering at T{sub N}<20 K. - Text3: Zigzig vs. cis-trans.

Rutzinger, D.; Bartsch, C. [Anorganische Chemie, Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, D-01062 Dresden (Germany); Doerr, M. [Institut fuer Festkoerperphysik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Rosner, H. [Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Str. 40, D-01187 Dresden (Germany); Neu, V. [IFW Dresden, Institut fuer metallische Werkstoffe, Helmholtzstr. 20, D-01069 Dresden (Germany); Doert, Th., E-mail: thomas.doert@chemie.tu-dresden.d [Anorganische Chemie, Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, D-01062 Dresden (Germany); Ruck, M. [Anorganische Chemie, Fachrichtung Chemie und Lebensmittelchemie, Technische Universitaet Dresden, D-01062 Dresden (Germany)

2010-03-15T23:59:59.000Z

298

Geochemistry of arsenic and metals in stored tailings of a Co–Ni arsenide-ore, Khovu-Aksy area, Russia  

Science Journals Connector (OSTI)

Interest in the redistribution of As-bearing species during long-term storage of hydrometallurgical tailings is motivated partly by the need to prevent As from being released into the environment. The speciation of As in mine wastes from the Tuva Cobalt Plant (Khovu-Aksy mine site, Tuva Republic, Russia) has been studied using mineralogical techniques, and chemical analyses of solids (tailings, soils, vegetation) and solutions (recovered pore waters, leach solutions). Ore at the plant was processed by hot autoclave leaching with an ammoniacal carbonate solution followed by treatment with CO2(gas) and caustic magnesite, MgO. Pronounced differences in element concentrations were measured in the five separate tailings ponds and one trench that were filled sequentially during operation of the plant. The concentration of each element was relatively uniform within each pond but the correlations among solid-phase Co, Ni, Zn and Cu gradually decrease from the most recent to oldest ponds as does the correlation between solid-phase As, Ag, Cd and Pb. In the oldest ponds, significant correlations are present between solid-phase Fe–As, Fe–Sb and Fe–Zn. High carbonate content in the ores and leaching reagents control the pH of the pore waters (pH = 7.27–9.10) where the major cation is Ca2+, followed by NH 4 + and Mg2+. Concentrations of As in pore solutions reach up to 140 mg L?1, and average 15 mg L?1. The high pore-water As concentrations are a consequence of instability of the processing residues, which include Mg(NH4)AsO4?nH2O and Mg3(AsO4)2?nH2O. The concentrations of Zn, Cu and As in pore waters increase from the youngest pond to the oldest storage impoundment (trench), which is evidence of the increase in element mobility with time. In contrast to the metals, As is preferentially sorbed to Fe oxides formed in the tailings. Aerosol transport of dust from the dry ponds has produced anomalies of As and metals in the surrounding area with As in the most polluted soils reaching up to 540 ppm. Moreover, vegetation growing on the surface of the disposal ponds absorbs solutes from the soil.

S. Bortnikova; E. Bessonova; O. Gaskova

2012-01-01T23:59:59.000Z

299

Simplified Numerical Description of Latent Storage Characteristics for Phase Change Wallboard  

E-Print Network (OSTI)

implemented in gypsum board, plaster or other wall-coveringimplemented in gypsum board, plaster or other wall-coveringbillion square meters of plaster board produced annually in

Fuestel, H.E.

2011-01-01T23:59:59.000Z

300

New insights into single-particle mixing state using aircraft aerosol time-of-flight mass spectrometry  

E-Print Network (OSTI)

with playas, including halite (NaCl), gypsum (CaSO 4. 2H 2playa evaporite minerals include halite, gypsum, mirabilite,

Pratt, Kerri Anne

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

GREEN:  

Science Journals Connector (OSTI)

......toxicity, poor solubility in solvents...germanium, and gallium arsenide, as well...Gallium arsenide is a compound...elements gallium and arsenic...gallons of water every day...release indium gallium arsenide, filling...byproduct is water. Ann Christy......

Green Impact of Hardware

2011-05-01T23:59:59.000Z

302

Ebic Investigation of the Recombination at the Edges of GaAs Solar Cells  

Science Journals Connector (OSTI)

Intermediate band photovoltaics is one of the so-called third generation photovoltaic device designs proposed to increase the efficiency of solar cells. It involves the creation of an intermediate ... traditional...

Andrea Scaccabarozzi; M. Acciarri

2013-01-01T23:59:59.000Z

303

Adsorption Kinetics of Hydrogen Sulfide and Thiols on GaAs (001) Surfaces in a Vacuum  

Science Journals Connector (OSTI)

For instance, a p(2 × 2) LEED structure, achieved upon repeated exposure to thiol and annealing to 750 K,9 implies that the surface concentration of chemisorbed sulfur could reach 0.25 monolayers. ... Funding for this research was provided by the Canadian Institutes for Health Research and the Canada Research Chair Program. ...

Oleksandr Voznyy; Jan J. Dubowski

2008-02-20T23:59:59.000Z

304

E-Print Network 3.0 - algaas-gaas issledovanie ehnergeticheskikh...  

NLE Websites -- All DOE Office Websites (Extended Search)

4 A COMPLETION CONJECTURE FOR KIRKMAN TRIPLE SYSTEMS Summary: BF A.M.Baraev, I.A.Faradzhev, Postroenie i issledovanie na EVM odnorodnykh i odnorod- nykh dvudol Source: Franek,...

305

Corrosion-induced degradation of GaAs PHEMTs under operation in high humidity conditions  

E-Print Network (OSTI)

We have comprehensively investigated the degradation mechanism of AlGaAs/InGaAs pseudomorphic high-electron-mobility transistors (PHEMTs) under operation in high humidity conditions. PHEMTs degradation under high humidity ...

Hisaka, Takayuki

306

Weak localization of dilute 2D electrons in undoped GaAs heterostructures.  

SciTech Connect

The temperature dependence of the resistivity and magnetoresistance of dilute 2D electrons are reported. The temperature dependence of the resistivity can be qualitatively described through phonon and ionized impurity scattering. While the temperature dependence indicates no ln(T) increase in the resistance, a sharp negative magnetoresistance feature is observed at small magnetic fields. This is shown to arise from weak localization. At very low density, we believe weak localization is still present, but cannot separate it from other effects that cause magnetoresistance in the semi-classical regime.

Seamons, John Andrew; Lilly, Michael Patrick; Reno, John Louis; Bielejec, Edward Salvador

2004-07-01T23:59:59.000Z

307

A study of microstrip T-juction discontinuity effects and modeling on GAAS substrates  

E-Print Network (OSTI)

. . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . 2 Microstrip T-junction discontinuity. . Microstrip T-junction geometry's. (a) symmetrical, (b) nonsymmetrical. . . . . . . . . . . . 4 Transmission line equivalent circuit model for a lossless T-junction. . . . S? for an ideal 3 port... transmission lines and structures. Through decades of research, analysis and measurement the electrical properties of micmstrip transmission lines can be calculated and predicted with great accuracy. However any variation &om a longitudinally straight...

Guill, Dennis Jarrett

2012-06-07T23:59:59.000Z

308

The design of GaAs HEMT and HBT Bessel-type transimpedance amplifiers  

E-Print Network (OSTI)

gain, and oo f?? 2= is bandwidth of the TIA represented by the transfer function H(s). Using Simulink, the output voltage V o in response to an input current at 1 bit/s is plotted for several values of the bandwidth , varying from 0.1Hz to 1Hz... gain, and oo f?? 2= is bandwidth of the TIA represented by the transfer function H(s). Using Simulink, the output voltage V o in response to an input current at 1 bit/s is plotted for several values of the bandwidth , varying from 0.1Hz to 1Hz...

Adeyemi, Oluwafemi Ibukunoluwa

2007-04-25T23:59:59.000Z

309

Investigation of the semiconductor–oxide electrolyte interface in GaAs utilizing electrolyte electroreflectance  

Science Journals Connector (OSTI)

We have investigated the electrolyte electroreflectance (EER) spectra of N–GaAs in the vicinity of the E o transition (direct gap at k?=0). A pronounced interference phenomenon sensitive to the d c b i a s e l e c t r i c f i e l d has been observed which we identify with an exciton quenching effect within the semiconductor space–charge region (SCR). We have utilized this excitonic feature to interferometrically probe the dynamic and steady?state properties of the SCR during electrochemical anodization procedures. The same EER spectra also exhibit Franz–Keldysh oscillations the period of which is explicitly dependent on the a c e l e c t r i c f i e l d. Using these phenomena we have shown that the interfacial and oxide electric fields under steady?state conditions are just sufficient to continue growing the oxide in compensation for slow dissolution. If the dc bias voltage is suddenly reduced the SCR temporarily collapses due to transient effects which we attribute to very slow interface states in the oxide. These techniques are applicable to the study of the SCR in a variety of semiconductor–electrolyte systems as well as in the Schottky barrier configuration.

R. P. Silberstein; F. H. Pollak

1980-01-01T23:59:59.000Z

310

GaAs on Si,,111...--crystal shape and strain relaxation in nanoscale patterned growth  

E-Print Network (OSTI)

electrolysis makes Cl2 C & F react to make CF4 & C2F6 C & Cl in presence of O dioxins? furans? #12;Sadoway, MIT

New Mexico, University of

311

Excitation-Dependent Recombination and Diffusion Near an Isolated Dislocation in GaAs  

SciTech Connect

In low-magnification, plan-view photoluminescence images of a nominally lattice-matched, undoped GaAs/GaInP heterostructure, we observe a random distribution of isolated dark spots. We attribute the dark spots to crystal dislocations, where nonradiative recombination is augmented by transitions utilizing defect-related energy levels between the conduction and valence bands. We note that, when the laser excitation intensity is reduced, the darkened regions expand. At lower excitation, the density of photogenerated electrons and holes is reduced, and they are more likely to reach the defective region before encountering a partner for radiative recombination. When we model the behavior with a simulation that allows for Laplacian diffusion and defect-related recombination only through mid-bandgap energy levels, we do not obtain good agreement between experimental and simulated images. But if we allow for an arbitrary distribution of defect levels, such that the occupation of the levels and bands can change independently, we have more flexibility for fitting the density-dependent recombination rates. The more sophisticated model produces results that are more consistent with experimental images.

Gfroerer, T. H.; Crowley, C. M.; Read, C. M.; Wanlass, M. W.

2012-06-01T23:59:59.000Z

312

Recent improvements in materials for thin GaAs and multibandgap solar cells  

SciTech Connect

The High Efficiency Concepts Program at SERI supports research on III-V compound semiconductors with the objective of achieving the maximum attainable photovoltaic conversion efficiencies for terrestrial solar electric power. The outcome of this research may also affect the future of space photovoltaic cells. While the interest in thin-film, high-efficiency solar cells for terrestrial applications is driven principally by consideration of system costs, such cells would also improve the power density of space power arrays.

Benner, J.P.

1985-05-01T23:59:59.000Z

313

Fourier spectroscopy of individual nitrogen impurity centers in GaAs  

SciTech Connect

We report on the measurement of the exciton homogeneous linewidth in nitrogen impurity centers in GaAs:N. Fourier spectroscopy on a single center revealed a long coherence time over 300 ps at low temperature. The narrowest linewidth obtained at liquid helium temperature is 3.5 ?eV, which is comparable with that of semiconductor quantum dots. The linewidth increases with increasing temperature, showing a thermally activated behavior with activation energies of 2?5 meV.

Ikezawa, Michio [PRESTO-JST, JST, Kawaguchi, Japan and Institute of Physics, University of Tsukuba, Tsukuba (Japan); Zhang, Liao; Mori, Tatsuya; Masumoto, Yasuaki [Institute of Physics, University of Tsukuba, Tsukuba (Japan); Sakuma, Yoshiki; Sakoda, Kazuaki [National Institute for Materials Science, Tsukuba (Japan)

2013-12-04T23:59:59.000Z

314

Simulations of Atomic Processes at Semiconductor Surfaces - General-Method and Chemisorption on Gaas(110)  

E-Print Network (OSTI)

& F(r)= ?2a ~ V(r) ( +py(r), (2.15) BU,)F"=? (2.22) so the strength of the electronic force is determined by the interatomic matrix element V(r) and its dependence on the separation of the atoms r. The equilibrium separation is given by 2a ~ V..., but Si bonding at the As?As bridge site 2. Notice that the x vibrations of Si have higher fre- quency than those of C, even though Si is a heavier atom. The reason, of course, is that Si sits between two As atoms, above the surface, and experiences...

MENON, M.; Allen, Roland E.

1988-01-01T23:59:59.000Z

315

Copper Doped GaAs Infrared Filter for the 8-13 m Atmospheric Window  

E-Print Network (OSTI)

regions of interest, such as atmospheric transmission windows. Filters exclude solar or thermal photonsCdTe is typically melt grown in a high temperature furnace. All three elements in this alloy are toxic. Stability

Peale, Robert E.

316

Electron transport in confined structures in very high mobility GaAs in perpendicular magnetic fields  

E-Print Network (OSTI)

In this thesis we study properties of two-dimensional electron transport through constrictions in perpendicular magnetic fields. We present two sets of experiments, one focusing on properties in the integer quantum Hall ...

Radu, Iuliana

2009-01-01T23:59:59.000Z

317

Surface Micromachined Components for a Safety Subsystem Application  

SciTech Connect

We have designed and fabricated a system using micromachining technologies that represents the first phase of an effort to develop a miniaturized or micro trajectory safety subsystem. Two Surface Micromachined (SMM) devices have been fabricated. The first is a device, denoted the Shuttle Mechanism, that contains a suspended shuttle that has a unique code imbedded in its surface. The second is a mechanical locking mechanism, denoted a Stronglink, that uses the code imbedded in the Shuttle Mechanism for unlocking. The Stronglink is designed to block a beam of optical energy until unlocked. A Photonic Integrated Circuit (PIC) fabricated in Gallium Arsenide (GaAs) and an ASIC have been designed to read the code contained in the Shuttle Mechanism. The ASIC interprets the data read by the PIC and outputs low-level drive signals for the actuators used by the Stronglink. An off-chip circuit amplifies the drive signals. Once the Stronglink is unlocked, a laser array that is assembled beneath the device is energized and light is transmitted through an aperture.

Garcia, E.J.; Holswade, S.; Plummer, D.W.; Polosky, M.A.; Shul, R.J.; Sulivan, C.T.

1999-03-04T23:59:59.000Z

318

Sedimentology 001 What is sedimentology?  

E-Print Network (OSTI)

Chemical rocks : produced from evaporation of water from a solution. Evaporites: halite, gypsum How do

Frank, Tracy D.

319

GEOL 103 Writing Assignment 3. Sedimentary Rocks Name _______________________  

E-Print Network (OSTI)

.g., kaolinite), halite (rock salt), gypsum, occasionally micas (muscovite, biotite). Sed rocks can also contain

Kirby, Carl S.

320

Chemie der Erde 65 (2005) 203270 INVITED REVIEW  

E-Print Network (OSTI)

. In the mesostasis are rare patches of a salt alteration assemblage: halite, siderite, and anhydrite/ gypsum

Treiman, Allan H.

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Geography 5: People and Earth's Ecosystems Lecture Outline  

E-Print Network (OSTI)

), evaporites (halite, gypsum), marine organisms or chemical precipitates (e.g. limestone) 12 Metamorphic Rocks

322

High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrator Application  

SciTech Connect

The High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrators project seeks to provide new photovoltaic cells for Concentrator Photovoltaics (CPV) Systems with higher cell efficiency, more favorable temperature coefficients and less sensitivity to changes in spectral distribution. The main objective of this project is to provide high efficiency III-V solar cells that will reduce the overall cost per Watt for power generation using CPV systems.This work is focused both on a potential near term application, namely the use of indium arsenide (InAs) QDs to spectrally "tune" the middle (GaAs) cell of a SOA triple junction device to a more favorable effective bandgap, as well as the long term goal of demonstrating intermediate band solar cell effects. The QDs are confined within a high electric field i-region of a standard GaAs solar cell. The extended absorption spectrum (and thus enhanced short circuit current) of the QD solar cell results from the increase in the sub GaAs bandgap spectral response that is achievable as quantum dot layers are introduced into the i-region. We have grown InAs quantum dots by OMVPE technique and optimized the QD growth conditions. Arrays of up to 40 layers of strain balanced quantum dots have been experimentally demonstrated with good material quality, low residual stain and high PL intensity. Quantum dot enhanced solar cells were grown and tested under simulated one sun AM1.5 conditions. Concentrator solar cells have been grown and fabricated with 5-40 layers of QDs. Testing of these devices show the QD cells have improved efficiency compared to baseline devices without QDs. Device modeling and measurement of thermal properties were performed using Crosslight APSYS. Improvements in a triple junction solar cell with the insertion of QDs into the middle current limiting junction was shown to be as high as 29% under one sun illumination for a 10 layer stack QD enhanced triple junction solar cell. QD devices have strong potential for net gains in efficiency at high concentration.

Hubbard, Seth

2012-09-12T23:59:59.000Z

323

Evidence of electronic polarization of the As ion in the superconducting phase of F-doped LaFeAsO  

Science Journals Connector (OSTI)

Charge-carrier redistribution invoked by enhanced electronic polarization of the As ion was observed in the superconducting phase of iron arsenide.

Kim, J.

2014-04-14T23:59:59.000Z

324

E-Print Network 3.0 - aluminium gallium indium Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

An advanced diffusion model to identify emergent research issues: the case of optoelectronic devices Summary: Aluminium arsenides Ge-Si alloys Avalanche photodiodes Indium...

325

Solar Innovation Timeline | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

cell Photo of two researchers analyzing a thin, circular shaped film under a small light. NREL researchers develop a gallium indium phosphidegallium arsenide solar cell...

326

History | Department of Energy  

Energy Savers (EERE)

cell Photo of two researchers analyzing a thin, circular shaped film under a small light. NREL researchers develop a gallium indium phosphidegallium arsenide solar cell...

327

Alta Devices Develops World Record Setting Thin-Film Solar Cell  

Office of Energy Efficiency and Renewable Energy (EERE)

EERE supported the development of Alta Devices' thin film Gallium Arsenide photovoltaic technology that set a world record for conversion efficiency.

328

Noncontact deep level photo-thermal spectroscopy: Technique and application to semi-insulating GaAs Wafers  

E-Print Network (OSTI)

to high resistivity materials, since the Debye-Huckel length is too large several milli- meters for semi materials. In DLPTS, the thermal recovery of carriers after excita- tion is monitored by a subNoncontact deep level photo-thermal spectroscopy: Technique and application to semi-insulating Ga

Mandelis, Andreas

329

SIMULATIONS OF A HIGH POWER 4H-SiC VJFET AND ITS GaAs COUNTERPART  

E-Print Network (OSTI)

of the two devices. The two-dimensional simulations were carried out using the ATLAS simulator from Silvaco

Myles, Charles W.

330

Projected Performance of Three- and Four-Junction Devices Using GaAs and GaInP  

E-Print Network (OSTI)

This paper explores the efficiencies expected for three- and four-junction devices for both space and terrestrial applications. For space applications, the effects of temperature and low concentration are investigated. For terrestrial applications, a concentration of 500 suns is assumed and the theoretical efficiencies are calculated as a function of spectral variations including the effects of air mass, turbidity, and water-vapor content. INTRODUCTION Ga 0.5 In 0.5 P/GaAs two-terminal, two-junction solar cells, invented and developed at the National Renewable Energy Laboratory, are in production at both TECSTAR and Spectrolab. The immediate market for these devices is in space; a future (potentially larger) market is terrestrial concentrator systems. The next-generation cells will add additional junction(s) in order to increase the efficiency. Work on a three-junction cell using an active Ge junction under the Ga 0.5 In 0.5 P/GaAs dual-junction cell has already been reported [1]. Ho...

Gainp; S. R. Kurtz; Sarah R. Kurtz; D. Myers; D. Myers; J.M. Olson; J. M. Olson

1997-01-01T23:59:59.000Z

331

Pseudomorphic growth of InAs on misoriented GaAs for extending quantum cascade laser wavelength  

SciTech Connect

The authors have studied the impact of epilayer strain on the deposition of InAs/GaAs on (100) and (111)B with 2° offset toward<2-1-1> surfaces. Consequences of a 7% lattice mismatch between these orientations in the form of three-dimensional growth are less apparent for (111)B with 2° offset toward<2-1-1> surfaces compared to (100). By exploring a range of molecular beam epitaxy process parameters for InAs/GaAs growth and utilizing scanning electron microscopy, atomic force microscopy, and Raman spectroscopy to evaluate the quality of these strained layers, the authors develop empirical models that describe the influence of the process conditions in regards to surface roughness with >92% accuracy. The smoothest InAs/GaAs samples demonstrated average surface roughness of 0.08 nm for 10 ?m{sup 2} areas, albeit at very low deposition rates. The authors have found the most important process conditions to be substrate temperature and deposition rate, leading us to believe that controlling diffusion length may be the key to reducing defects in severely strained structures. InGaAs/AlGaAs quantum cascade laser structures were also produced on (111)B with 2° offset toward<2-1-1> to take advantage of the piezoelectric effect, and the modified laser transitions due to these effects were observed.

Meyer, Charles; Cheng, Emily; Grayer, Justin; Mueller, David; Triplett, Gregory; Roberts, Denzil [Department of Electrical and Computer Engineering, University of Missouri, 349 Engineering Building West, Columbia, Missouri 65201 (United States)] [Department of Electrical and Computer Engineering, University of Missouri, 349 Engineering Building West, Columbia, Missouri 65201 (United States); Graham, Samuel [Georgia Institute of Technology, Woodruff School of Mechanical Engineering, Atlanta, Georgia 30332 (United States)] [Georgia Institute of Technology, Woodruff School of Mechanical Engineering, Atlanta, Georgia 30332 (United States)

2013-11-15T23:59:59.000Z

332

Si diffusion and segregation in low-temperature grown GaAs K. L. Kavanagh and J. C. P. Chang  

E-Print Network (OSTI)

spectroscopy (SIMS) using a Cs ion beam, and cross-sectional transmission electron micros- copy (TEM) using- files from SIMS data for a three layer LT-GaAs sample after anneals at 9-00"C for 10, 30 (forming gas

Woodall, Jerry M.

333

Cyclotron resonance to 100 mK of a GaAs heterojunction in the ultra-quantum limit  

Science Journals Connector (OSTI)

A helium dilution refrigerator has been modified to enable cyclotron resonance measurements to 100 mK on low-density, 2D electron systems in the ultra-quantum limit. Previous cyclotron resonance work to 300 mK indicates the presence of a phase boundary at a filling factor of vc?110, separating gas-like behavior at vmK, the system is spin polarized only at low values of v.

J.G. Michels; S. Hill; R.J. Warburton; G.M. Summers; P. Gee; J. Singleton; R.J. Nicholas; C.T. Foxon; J.J. Harris

1994-01-01T23:59:59.000Z

334

Kinetics of the inner ring in the exciton emission pattern in coupled GaAs quantum wells  

Science Journals Connector (OSTI)

We report on the kinetics of the inner ring in the exciton emission pattern. The formation time of the inner ring following the onset of the laser excitation is found to be about 30 ns. The inner ring is also found to disappear within 4 ns after the laser termination. The latter process is accompanied by a jump in the photoluminescence (PL) intensity. The spatial dependence of the PL jump indicates that the excitons outside of the region of laser excitation, including the inner ring region, are efficiently cooled to the lattice temperature even during the laser excitation. The ring formation and disappearance are explained in terms of exciton transport and cooling.

A. T. Hammack, L. V. Butov, J. Wilkes, L. Mouchliadis, E. A. Muljarov, A. L. Ivanov, and A. C. Gossard

2009-10-29T23:59:59.000Z

335

GaAs Clusters in the Quantum Size Regime: Growth on High Surface Area Silica by Molecular Beam Epitaxy  

Science Journals Connector (OSTI)

...cathodoluminescence ex-periments. Many useful comments on our manu-script were made by K. Kash, J. M. Worlock, and M. Saifi. We are especially gratefill to D. E. Aspnes for making concrete suggestions for the improvement ofour report. 8 May 1989...

C. J. SANDROFF; J. P. HARBISON; R. RAMESH; M. J. ANDREJCO; M. S. HEGDE; C. C. CHANG; E. M. VOGEL; D. M. HWANG

1989-07-28T23:59:59.000Z

336

High-quality quantum point contact in two-dimensional GaAs ,,311...A hole system  

E-Print Network (OSTI)

. R. Petta,2 and M. Shayegan1 1 Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA 2 Department of Physics, Princeton University, Princeton, New Jersey 08854, USA 40 nm deep, using an electron cyclotron resonance plasma etcher with ZEP 520A resist as an etch mask

Petta, Jason

337

Inelastic Neutron Scattering Study of a Nonmagnetic Collapsed Tetragonal Phase in Nonsuperconducting CaFe2As2: Evidence of the Impact of Spin Fluctuations on Superconductivity in the Iron-Arsenide Compounds  

SciTech Connect

The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the nonsuperconducting collapsed tetragonal phase of CaFe2As2 via inelastic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetragonal phase of CaFe2As2 is nonmagnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.

Soh, Jing-Han [Ames Laboratory; Tucker, Ggregory S. [Ames Laboratory; Pratt, Daniel K. [Ames Laboratory; Abernathy, D. L. [Oak Ridge National Laboratory; Stone, M. B. [Oak Ridge National Laboratory; Ran, Sheng [Ames Laboratory; Budko, Sergey L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory; Kreyssig, Andreas [Ames Laboratory; McQueeney, Robert J. [Ames Laboratory; Goldman, Alan I. [Ames Laboratory

2013-11-27T23:59:59.000Z

338

Inelastic neutron scattering study of a nonmagnetic collapsed tetragonal phase of CaFe2As2: Evidence of the impact of spin fluctuations on superconductivity in the iron-arsenide compounds.  

SciTech Connect

The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the non-superconducting collapsed tetragonal phase of CaFe2As2 via inelas- tic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetrag- onal phase of CaFe2As2 is non-magnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.

Soh, Jing Han [ORNL] [ORNL; Tucker, G. S. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; Pratt, Daniel K [ORNL] [ORNL; Abernathy, Douglas L [ORNL] [ORNL; Stone, Matthew B [ORNL] [ORNL; Ran, S. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; Budko, S L [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; Canfield, P. C. [Ames Laboratory] [Ames Laboratory; Kreyssig, A. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; McQueeney, R. J. [Ames Laboratory] [Ames Laboratory; Goldman, A. I. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University

2013-01-01T23:59:59.000Z

339

Thermal Performance of Phase Change Wallboard for Residential Cooling Application  

E-Print Network (OSTI)

implemented in gypsum board, plaster or other wall-coveringimbedded in gypsum board, plaster or other wall-covering7 billion square meters of plaster board are being produced

Feustel, H.E.

2011-01-01T23:59:59.000Z

340

Reactive Geochemical Transport Modeling of Concentrated Aqueous Solutions: Supplement to TOUGHREACT User's Guide for the Pitzer Ion-Interaction Model  

E-Print Network (OSTI)

gypsum, niter, soda niter, halite, sylvite, epsomite, Mg(NO7 1.0E-8 1.0E-9 Gypsum Halite CaCl2:2H2O Sylvite Calcite Na+

Zhang, Guoxiang; Spycher, Nicolas; Xu, Tianfu; Sonnenthal, Eric; Steefel, Carl

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Effect of polysaccharides on the hydration of cement paste at early A. Peschard, A. Govin*  

E-Print Network (OSTI)

. [9,10] found that addition of glucose, gluconate or lignosulfonate stabilizes ettringite in the C3A-gypsum system. It was also noted that glucose retards gypsum consumption and ettringite formation. Many studies

Paris-Sud XI, Université de

342

Accumulation and replacement of exchangeable sodium in soils of Southeast Texas under turfgrass and its effect on soil infiltration rate  

E-Print Network (OSTI)

in soils of this area. This study assessed the degree of Na accumulation on cation exchange sites as affected by gypsum treatments in soils that support turfgrass (bermudagrass) and the response of soil infiltration rate to different rates of gypsum...

Aydemir, Salih

2012-06-07T23:59:59.000Z

343

DECOVALEX-THMC Task D: Long-Term Permeability/Porosity Changes in the EDZ and Near Field due to THM and THC Processes in Volcanic and Crystaline-Bentonite Systems, Status Report October 2005  

E-Print Network (OSTI)

calcite (primary and secondary), halite (secondary) Mineralr02 cristoba-a fluorite gypsum halite hematite heuland/10

Birkholzer, J.; Rutqvist, J.; Sonnenthal, E.; Barr, D.

2005-01-01T23:59:59.000Z

344

MAPPING MINERALS AT A POTENTIAL MARS ANALOG SITE ON THE TIBETAN PLATEAU, David. P. Mayer1  

E-Print Network (OSTI)

library [6]. Certain minerals, such as halite and large (up to 15 cm long) crystals of gypsum, were easily

345

Lifecycle Assessment of Beijing-Area Building Energy Use and Emissions: Summary Findings and Policy Applications  

E-Print Network (OSTI)

Production Intensity Material kg/m Section Steel Steel Bar Aluminum Cement Glass Gypsum board* Acrylic Rubber -

Aden, Nathaniel

2010-01-01T23:59:59.000Z

346

This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination. IEEE JOURNAL OF PHOTOVOLTAICS 1  

E-Print Network (OSTI)

as presented, with the exception of pagination. IEEE JOURNAL OF PHOTOVOLTAICS 1 Gallium Arsenide Solar Cell--Gallium arsenide, nanospheres, photovoltaic systems, whispering gallery modes (WGMs). I. INTRODUCTION THE route as the active layer is thinned [2]. Thin-film photovoltaics offer the possibility to significantly reduce

Atwater, Harry

347

PRP38 encodes a yeast protein required for pre-mRNA splicing and maintenance of stable U6 small nuclear RNA levels.  

Science Journals Connector (OSTI)

...TCA ATO TAC TAT AAA OTA AAT CTA AUC AAC OAA TCT TTO ALA aOC AAT ACA ATO OTA GAO CTT TTG AAA TOT TCT CTA TTT TAL GTA...CAA TOO AAT AAA ATA TAC AAC TCT GAT GAA GAG AOT AOT TCT AOC GAA AOC GAA AOT AAT GGT GAC AOT GAA OAT GAC AAC GAC ACC AOC OTT...

S Blanton; A Srinivasan; B C Rymond

1992-09-01T23:59:59.000Z

348

Complementary GaAs Technology for High-Speed VLSI Circuits Richard B. Brown, Bruce Bernhardt*, Mike LaMacchia**, Jon Abrokwah***, Phiroze N. Parakh,  

E-Print Network (OSTI)

, Claude R. Gauthier, David Foster**, Brian Crawforth**, Timothy McQuire**, Karem Sakallah, Ronald J. Lomax

Mudge, Trevor

349

Complementary GaAs Technology for HighSpeed VLSI Circuits Richard B. Brown, Bruce Bernhardt*, Mike LaMacchia**, Jon Abrokwah***, Phiroze N. Parakh,  

E-Print Network (OSTI)

, Claude R. Gauthier, David Foster**, Brian Crawforth**, Timothy McQuire**, Karem Sakallah, Ronald J. Lomax

Mudge, Trevor

350

Critical size for the generation of misfit dislocations and their effects on electronic properties in GaAs nanosheets on Si substrate  

E-Print Network (OSTI)

-Queisser limit6 for the solar-cell efficiency. Recently, NWs of various semi- conductors such as GaAs/AlGaAs,7

Southern California, University of

351

Strain relief by periodic misfit arrays for low defect density GaSb on GaAs S. H. Huang, G. Balakrishnan, A. Khoshakhlagh, A. Jallipalli,  

E-Print Network (OSTI)

Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 Received 17 June 2005 be enabled, includ- ing monolithically integrated lasers, detectors, solar cells, and transistors.4 However

New Mexico, University of

352

Study of the interface of undoped and p?doped ZnSe with GaAs and AlAs  

Science Journals Connector (OSTI)

We have used electrolyte electroreflectance (EER) to characterize ZnSe/GaAs and ZnSe/AlAs interfaces. The great sensitivity of EER to interface space?charge regions enabled us to detect both interface crossover transitions and transitions to triangular?well interface states. The observation of these transitions provides the first unambiguous proof that the ZnSe/GaAs interface is type I and allowed us to determine the band offsets and band bendings the diffusion lengths across each interface and the amount of interdiffusion.

L. Kassel; H. Abad; J. W. Garland; P. M. Raccah; J. E. Potts; M. A. Haase; H. Cheng

1990-01-01T23:59:59.000Z

353

In situ metal-organic chemical vapor deposition atomic-layer deposition of aluminum oxide on GaAs using trimethyaluminum  

E-Print Network (OSTI)

IPA is chosen as the oxygen source for the ALD in the MOCVD. Second, IPA will not react precursor pulse time. b Dependence of ALD Al2O3 growth rate on temperature. The pulse time for TMA and IPA

354

Ralisation et caractrisation d'un transistor effet de champ JFET au GaAs en vue de son intgration avec une photodiode  

E-Print Network (OSTI)

intégration avec une photodiode M. T. Belaroussi, F. Therez et R. Alcubilla (*) Laboratoire d'Automatique et d étendus à la fabrication du circuit intégré GaAlAs-GaAs associant une photodiode à un TEC. Abstract. 2014AlAs-GaAs monolithic integration of a photodiode and FET. Revue Phys. Appl. 22 (1987) 77-82 JANVIER 1987

Paris-Sud XI, Université de

355

SUPPRESSION OF ANTIPHASE DISORDER IN GaAs GROWN ON RELAXED GeSi BUFFERS BY METAL-ORGANIC CHEMICAL VAPOR DEPOSITION  

E-Print Network (OSTI)

. Fitzgerald, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139. ABSTRACT Due of high-efficiency III-V solar cells. By effectively bridging the gap between the Ge and Si lattice

356

Atomic-Resolution Image of GaAs(110) Surface with an Ultrahigh-Vacuum Atomic Force Microscope (UHV-AFM)  

Science Journals Connector (OSTI)

The first demonstration of atomic-resolution imaging of a GaAs(HO) surface with an ultrahigh vacuum atomic force microscope (UHV-AFM) was performed. We also observed ... GaAs(llO). This result suggests that the UHV

Y. Sugawara; M. Ohta; K. Hontani; S. Morita; F. Osaka…

1995-01-01T23:59:59.000Z

357

60 GHz Harmonic Optoelectronic Up-Conversion Using an InAlAs/InGaAs Metamorphic High-Electron-Mobility Transistor on a GaAs Substrate  

E-Print Network (OSTI)

60 GHz Harmonic Optoelectronic Up-Conversion Using an InAlAs/InGaAs Metamorphic High optoelectronic up-conversion using an InAlAs/InGaAs metamorphic high-electron-mobility transistor (HEMT) on a Ga 1 GHz signals into a 60 GHz band. After investigating the dependences of optoelectronic mixing

Choi, Woo-Young

358

Synchrotron Photoemission Analysis of Semiconductor/Electrolyte Interfaces by the Frozen-Electrolyte Approach:? Interaction of HCl in 2-Propanol with GaAs(100)  

Science Journals Connector (OSTI)

(14)?Laukkanen, P.; Kuzmin, M.; Perälä, R. E.; Vaara, R. L.; Väyrynen, I. J. Appl. ... Laukkanen, P.; Kuzmin, M.; Perala, R. E.; Vaara, R.-L.; Vayrynen, I. J. ...

Thomas Mayer; Mikhail V. Lebedev; Ralf Hunger; Wolfram Jaegermann

2006-01-19T23:59:59.000Z

359

A quantitative conduction model for a low-resistance nonalloyed ohmic contact structure utilizing low-temperature-grown GaAs  

E-Print Network (OSTI)

A quantitative conduction model for a low-resistance nonalloyed ohmic contact structure utilizing properties of this material. The specific contact resistance is then calculated using an analytic expression for tunneling conduction through an equivalent uniformly doped Schottky barrier. The model has been used to fit

Woodall, Jerry M.

360

Imaging with Mass Spectrometry: A SIMS and VUV-Photoionization Study of Ion-Sputtered Atoms and Clusters from GaAs and Au  

E-Print Network (OSTI)

photoionization efficiency (PIE) curves to be obtained forunique wavelength- dependent PIE of each sputtered neutralpresented PI spectra and PIE curves. Optimized SIMS settings

Takahashi, Lynelle

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-Junction Solar Cells Under Concentration: Resistance Study  

SciTech Connect

The following four TJ designs, AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs are studied to determine minimum doping concentration to achieve a resistance of <10{sup -4} {omega}{center_dot}cm{sup 2} and a peak tunneling current suitable for MJ solar cells up to 1500-suns concentration (operating current of 21 A/cm{sup 2}). Experimentally calibrated numerical models are used to determine how the resistance changes as a function of doping concentration. The AlGaAs/GaAs TJ design is determined to require the least doping concentration to achieve the specified resistance and peak tunneling current, followed by the GaAs/GaAs, and AlGaAs/AlGaAs TJ designs. The AlGaAs/InGaP TJ design can only achieve resistances >5x10{sup -4} {omega}cm{sup 2}.

Wheeldon, Jeffrey F.; Valdivia, Christopher E.; Walker, Alex; Kolhatkar, Gitanja; Hall, Trevor J.; Hinzer, Karin [Centre for Research in Photonics, University of Ottawa, Ottawa, ON (Canada); Masson, Denis; Riel, Bruno; Fafard, Simon [Cyrium Technologies Inc., Ottawa, ON (Canada); Jaouad, Abdelatif; Turala, Artur; Ares, Richard; Aimez, Vincent [Centre de Recherche en Nanofabrication et en Nanocaracterisation CRN2, Universite de Sherbrooke, Sherbrooke, QC (Canada)

2010-10-14T23:59:59.000Z

362

X-ray Topography of Threading Dislocations in Aluminum Nitride  

NLE Websites -- All DOE Office Websites (Extended Search)

eV, and 6.2 eV, respectively. They form a continuous range of compounds useful for optoelectronic sources and detectors at UV wavelengths, much like the III-V arsenides and III-V...

363

Gordon Research Conferences  

Science Journals Connector (OSTI)

...Polysac-charide adsorbents for ethanol-water separation." Membrane processes...boundaries in semiconduc-tors:" Gallium arsenide thin films (C. B. Duke, session...transduction." 20 August. Ion and water movements across epithelial membranes...

Alexander M. Cruickshank

1981-03-13T23:59:59.000Z

364

Spectroscopic Study of the Simultaneous Adsorption of PVP and Azelaic Acid on ?-Alumina  

Science Journals Connector (OSTI)

A 180° backscattering geometry and an indium gallium arsenide detector were applied. ... The azelaic acid concentration was not equal in the two solvents, due to the limited solubility in water. ...

Ildikó Száraz; Willis Forsling

2001-05-23T23:59:59.000Z

365

Gordon Research Conferences  

Science Journals Connector (OSTI)

...Robert Charles Allen, "Water in epoxy resins. Thermodynamics...Raman scat-tenng in gallium arsenide." Robert Silby, "Many...Princeton, NJ 08544. Water and Aqueous Solutions...structure and dynamics of water (A. H. Narten, discussion...

ALEXANDER M. CRUICKSHANK

1986-03-07T23:59:59.000Z

366

Hydrogen and minor element incorporation in synthetic rutile  

Science Journals Connector (OSTI)

...in a decrease in H solubility. Variation in the solubility of different oxides...substitution|solubility|spectroscopy...GPa, 1100C under water-saturated conditions...MnTiO3 (Ti), gallium arsenide (Ga), chromium...

G. D. Bromiley; N. Hilairet

367

Geochemical Evolution of a High Arsenic, Alkaline Pit-Lake in the Mother Lode Gold District, California  

Science Journals Connector (OSTI)

...cobalt metals, gallium arsenide, galena, wollastonite...ultrapure (MilleQ) water and analyzed as...account for its higher solubility in ground water relative to waters...reflect the lower solubility of CO2 in water with slightly higher...

Kaye S. Savage; Roger P. Ashley; Dennis K. Bird

368

Gordon Research Conferences: Program for 1967  

Science Journals Connector (OSTI)

...chromatography"; K. L. Hoy, "Uses of solubility parameter." 21 July. E. B...Davey, "Growth and properties of gallium arsenide films (C. Feldman, discussion...desert sand glass"; I. Burn, "Water in fused SiO2." 1 September...

W. George Parks

1967-03-10T23:59:59.000Z

369

Gordon Research Conferences  

Science Journals Connector (OSTI)

...developments in water-borne coatings...Hoy, "Separating solubility parameters of polymers...experiments." 18 July. Gallium arsenide (R. K. Wil-lardson...processes in surface waters"; T. Graedel...Thermodesorption of water from glass fiber...

Alexander M. Cruickshank

1985-03-01T23:59:59.000Z

370

Model Code for the Control of Residential HVAC Distribution System Leakage and HVAC-Induced Building Leakage  

E-Print Network (OSTI)

, Underwriters Laboratories, Inc., the Air Conditioning Contractors Of America, the Thermal Insulation Manufacturers Association, the National Fire Protection Association, and the Gypsum Association....

Wemhoff, P.

1990-01-01T23:59:59.000Z

371

Irrigation Water Quality Salinity Management  

E-Print Network (OSTI)

Na2SO4 Moderate to large Calcium chloride CaCl2 Moderate Calcium sulfate (gypsum) CaSO4 2H2O Moderate

372

International Symposium on Site Characterization for CO2 Geological Storage  

E-Print Network (OSTI)

and limestone; extensive halite beds in SE Black Mesa basindeposits include gypsum and halite. The fine-grained unitsParadox Formation shale, halite, and anhydrite serve as

Tsang, Chin-Fu

2006-01-01T23:59:59.000Z

373

Introduction to Geomorphology Lecture 1 1  

E-Print Network (OSTI)

of this debris get compacted and cemented together (sandstone, mudstone, limestone, Halite). 3) Metamorphic Inorganic Biochemical Limestone (calcite) Dolomite Halite Gypsum Limestone (calcite) Chert Coal

Venditti, Jeremy G.

374

Soils and Brine Geochemistry and Mineralogy of Hyperarid Desert Playa, Ouargla Basin,  

E-Print Network (OSTI)

controlled by the following precipitation sequence: calcite > gypsum > mirabilite > halite. This sequence ðmirabilite-thenardite-halite paragenesis�, controlling the process of dissolution= precipitation of g

Ahmad, Sajjad

375

Proceedings of the TOUGH Symposium 2009  

E-Print Network (OSTI)

precipitation behav- iour of ettringite, monosulfate, andtherein. Set similar to ettringite. Also, see Marty et al. (Assumed to be similar to ettringite. Brucite and gypsum were

Moridis, George J.

2010-01-01T23:59:59.000Z

376

Building Stones  

E-Print Network (OSTI)

Ancient Egyptian limestone quarries: A petrological survey.pp. 195 - 212. 2001 Ancient quarries near Amarna. Egyptian36 - 38. 2010 An early Roman quarry for anhydrite and gypsum

2012-01-01T23:59:59.000Z

377

GALLIUM--2002 29.1 References that include a section mark () are found in the Internet  

E-Print Network (OSTI)

consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices application for gallium, with 46% of total consumption. Optoelectronic devices accounted for 42% of domestic

378

doi: 10.1149/1.2108814 1986, Volume 133, Issue 6, Pages 1176-1179.J. Electrochem. Soc.  

E-Print Network (OSTI)

-Si/GaAs interfaces have been prepared by depositing hydrogenated amorphous Si (a-Si:H) onto GaAs in a silane plasma is the case for other lattice mismatched GaAs heterojunctions and most

Woodall, Jerry M.

379

JOURNAL DE PHYSIQUE Colloque CS, supplment au n12, Tome 43, dcembre 1982 page C5-323  

E-Print Network (OSTI)

in optical communications. MOVPE growth of GaAs, P , the classical mate- rial for light emitting diodes (LED

Boyer, Edmond

380

Doping of G Molecular Layer D  

E-Print Network (OSTI)

- Sn MCCs (Na4Sn2S6) GaAs substrate Doping Profile of a S-Sn doped (100) GaAs wafer g S-Sn doped Ga Based on three steps: Band Diagram of GaAs Based on three steps: I Reaction of dopant containing

Candea, George

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Early C3A hydration in the presence of different kinds of calcium1 S. Pourcheta*  

E-Print Network (OSTI)

formation observed before ettringite18 precipitation in the C3A-gypsum system is avoided as soon then higher nucleation frequency with regard to the ettringite obtained in the21 presence of hemihydrate. Moreover, replacement of gypsum by hemihydrate also22 leads to an increase of the ettringite formation rate

Paris-Sud XI, Université de

382

Buildings Energy Data Book: 1.6 Embodied Energy of Building Assemblies  

Buildings Energy Data Book (EERE)

6 6 Embodied Energy of Commercial Interior Wall Assemblies in the U.S. Embodied Energy CO2 Equivalent Interior Wall Type (2) (MMBtu/SF) (1) Emissions (lbs/SF) 2x4 wood stud (16" OC) + gypsum board (3) 0.03 2.84 2x4 wood stud (24" OC) + gypsum board (3) 0.03 2.78 2x4 wood stud (24" OC) + 2 gypsum boards (4) 0.04 4.45 Steel stud (16" OC) + gypsum board (4) 0.04 3.99 Steel stud (24" OC) + gypsum board (4) 0.04 3.64 Steel stud (24" OC) + 2 gypsum boards 0.05 5.31 6" Concrete block + gypsum board 0.21 34.02 6" Concrete block 0.19 32.34 Clay brick (4") unpainted 0.05 6.97 Note(s): Source(s): Assumptions: Values are general estimations for the U.S. 60 year building lifetime. Low rise building. 1) Embodied Energy: Energy use includes extraction, processing, transportation, construction, and disposal of each material. 2) All interior walls include two coats of latex paint

383

Functional materials: electronics, information and sensors  

Science Journals Connector (OSTI)

Functional materials are those that have properties enabling them to preform a specific functional purpose, e.g. electrical, magnetic or optical. The rapid development of the technology of transistors and intergrated circuits will continue into the future with design incorporating new materials, notably gallium arsenide. Silica glass is finding increasing application in photonics, light emitting diodes and optical fibres for telephone cables. Optical-fibre technology depends on reliable and durable lasers which now use compound semiconductors such as indium-gallium-arsenide phosphide. It is anticipated that new materials application (indium-gallium-arsenide phosphide) will contribute towards progress in photovoltaics. Interest in superconducting material has heightened during 1980s with the promise that high-temperature superconductivity offers for more-efficient power generation and transmission. In future advantage will come from developing economic and reliable ways of producing functional materials to meet increasing demand.

Merton C. Flemings

1990-01-01T23:59:59.000Z

384

Demonstration of InAsBi photoresponse beyond 3.5??m  

SciTech Connect

An Indium Arsenide Bismide photodiode has been grown, fabricated, and characterized to evaluate its performance in the Mid Wave Infrared region of the spectrum. Spectral response from the diode has been obtained up to a diode temperature of 225?K. At this temperature, the diode has a cut off wavelength of 3.95 ?m, compared to 3.41 ?m in a reference Indium Arsenide diode, indicating that Bismuth has been incorporated to reduce the band gap of Indium Arsenide by 75?meV. Similar band gap reduction was deduced from the cut off wavelength comparison at 77?K. From the dark current data, shunt resistance values of 8 and 39 ? at temperatures of 77 and 290?K, respectively, were obtained in our photodiode.

Sandall, I. C., E-mail: I.sandall@sheffield.ac.uk; Bastiman, F.; White, B.; Richards, R.; Mendes, D.; David, J. P. R.; Tan, C. H. [Department of Electronic and Electrical Engineering, The University of Sheffield, Sir Frederick Mappin Building, Mappin Street, Sheffield S1 3JD (United Kingdom)

2014-04-28T23:59:59.000Z

385

Clean process to destroy arsenic-containing organic compounds with recovery of arsenic  

DOE Patents (OSTI)

A reduction method is provided for the treatment of arsenic-containing organic compounds with simultaneous recovery of pure arsenic. Arsenic-containing organic compounds include pesticides, herbicides, and chemical warfare agents such as Lewisite. The arsenic-containing compound is decomposed using a reducing agent. Arsine gas may be formed directly by using a hydrogen-rich reducing agent, or a metal arsenide may be formed using a pure metal reducing agent. In the latter case, the arsenide is reacted with an acid to form arsine gas. In either case, the arsine gas is then reduced to elemental arsenic. 1 fig.

Upadhye, R.S.; Wang, F.T.

1996-08-13T23:59:59.000Z

386

Indirect excitons in GaAs coupled quantum wells : development of optoelectronic logic devices and trapping potentials, and studies of low temperature phenomena in a bosonic condensed matter system  

E-Print Network (OSTI)

the develop- ment of optoelectronics but also in the studiesof exciton based optoelectronics, that of scalability, willin exciton-based optoelectronics have been made. This

High, Alexander Arthur; High, Alexander Arthur

2012-01-01T23:59:59.000Z

387

Indirect excitons in GaAs coupled quantum wells : development of optoelectronic logic devices and trapping potentials, and studies of low temperature phenomena in a bosonic condensed matter system  

E-Print Network (OSTI)

5608–5611. Butov, L. V. , Mintsev, A. V. , Lozovik, Y. E. ,18), 187402. Yang, S. , Mintsev, A. , Hammack, A. , Butov,

High, Alexander Arthur; High, Alexander Arthur

2012-01-01T23:59:59.000Z

388

Summary Abstract: The MBE growth of GaAs free of oval defects G. D. Pettit, J. M. Woodall, S. L. Wright, P. D. Kirchner, and J. L. Freeouf  

E-Print Network (OSTI)

. Wright, P. D. Kirchner, and J. L. Freeouf IBM Thomas J. Watson Research Center, Yorktown Heights, New

Woodall, Jerry M.

389

A New Concept in Dryer Control  

E-Print Network (OSTI)

, lumber, fiberboard, gypsum board, crumb rubber, etc. In addition, such dryer types as Rotary Drum, Suspension, Flash, Through, Spray, Oven, Tray, Lime Kilns, etc., should be amenable to control utilizing this model. Moreover, it should apply to most thin...

Robinson, J. W.

390

Rock-water interactions of the Madison Aquifer, Mission Canyon Formation, Williston Basin, North Dakota  

E-Print Network (OSTI)

system. Results (i.e., degree of saturation with respect to calcite, dolomite, halite, gypsum, and anhydrite) were integrated with a graphical matrix analysis program to produce color-coded maps that depict potential precipitation-dissolution boundaries...

Spicer, James Frank

2012-06-07T23:59:59.000Z

391

Cyclic and Reciprocal Sedimentation in Virgilian Strata of Southern New Mexico  

Science Journals Connector (OSTI)

...INTERPRETATION OF THE BASINAL CYCLES OF PANTHER SEEP FORMATION The beds described heretofore are termed the "Panther Seep fades" (Kottlowski and others...mentos to the center of the gypsum and car- bonate tidal-flat area, or about...

392

Cryptantha gypsophila (Boraginaceae: Boraginoideae), a new species from western Colorado  

Science Journals Connector (OSTI)

Cryptantha gypsophila, a new species of sect.Oreocarya..., is described from gypsum outcrops in widely scattered valleys of Mesa, Montrose, and San Miguel countries of western Colorado. It can be...

James L. Reveal; C. Rose Broome

393

Building America Technlogy Solutions for New and Existing Homes: Interior Foundation Insulation Upgrade- Minneapolis Residence (Fact Sheet)  

Energy.gov (U.S. Department of Energy (DOE))

This interior foundation project employed several techniques to improve performance and mitigate moisture issues: dimple mat; spray polyurethane foam insulation; moisture and thermal management systems for the floor; and paperless gypsum board and steel framing.

394

Effects of tunneling on groundwater flow and swelling of clay-sulfate rocks  

E-Print Network (OSTI)

[1] Swelling of clay-sulfate rocks is a major threat in tunneling. It is triggered by the transformation of the sulfate mineral anhydrite into gypsum as a result of water inflow in anhydrite-containing layers after tunnel ...

Butscher, Christoph

395

Rheologica Acta manuscript No. (will be inserted by the editor)  

E-Print Network (OSTI)

.g., in plasterboard production, in which a foamed plaster slurry is prepared by mixing an aqueous foam with a gypsum plaster slurry, in foam con- crete production by pre-foaming methods, where aqueous foam is mixed

Boyer, Edmond

396

insu-00305234,version1-18Feb2011 Author manuscript, published in "Geo-Marine Letters 26, 6 (2006) 347-359" DOI : 10.1007/s00367-006-0044-0  

E-Print Network (OSTI)

, of seismically very high amplitude stratified facies, composed of halite, gypsum and marls), (ii) the salt layer, with a transparent seismic facies made of halite, and (iii) the lower evaporites that were never drilled

Paris-Sud XI, Université de

397

ENDOLITHIC HALOPHILES FOUND IN EVAPORITE SALTS ON TIBET PLATEAU AS A POTENTIAL ANALOG FOR MARTIAN LIFE IN SALINE ENVIRONMENT. F. J. Kong1  

E-Print Network (OSTI)

of arid region were found and investigated. They showed that halite rocks are colonized by Chroococ at the surface. The major salts within crusts are halite and gypsum. Mg-sulfates with different hydration degrees

398

Christmas Island lagoonal lakes, models for the deposition of carbonateevaporiteorganic laminated sediments  

E-Print Network (OSTI)

, halite) and organic layers are deposited. Observations suggest that deposition of these different laminae), followed by evaporitic minerals (carbonate, calcium sulfate, halite) when salinity increases through Laminated series displaying sequential alternations of evaporitic (anhydrite, gypsum, halite) and carbonate

Boyer, Edmond

399

Proceedings of the TOUGH Symposium 2009  

E-Print Network (OSTI)

be similar to ettringite. Brucite and gypsum were assumed toof the reservoir precipitates as brucite (Mg(OH) 2 ). ThisDistance from reservoir (m) brucite, and CSH:1.7, with an

Moridis, George J.

2010-01-01T23:59:59.000Z

400

Analysis of Energy-Efficiency Opportunities for the Cement Industry in Shandong Province, China  

E-Print Network (OSTI)

like blast furnace slag, fly ash, coal gangue, limestone,In ordinary VSKs, high-ash anthracite coal and raw materialsAsh Limestone Gypsum Other (please specify) Other (please specify) Total Yearly Energy Consumption (ton) Coal

Price, Lynn

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Environmental chamber measurements of mercury flux from coal utilization by-products  

SciTech Connect

An environmental chamber was constructed to measure the mercury flux from coal utilization by-product (CUB) samples. Samples of fly ash, FGD gypsum, and wallboard made from FGD gypsum were tested under both dark and illuminated conditions with or without the addition of water to the sample. Mercury releases varied widely, with 7-day experiment averages ranging from -6.8 to 73 ng/m2 h for the fly ash samples and -5.2 to 335 ng/m2 h for the FGD/wallboard samples. Initial mercury content, fly ash type, and light exposure had no observable consistent effects on the mercury flux. For the fly ash samples, the effect of a mercury control technology was to decrease the emission. For three of the four pairs of FGD gypsum and wallboard samples, the wallboard sample released less (or absorbed more) mercury than the gypsum.

Pekney, N.J.; Martello, D.V.; Schroeder, K.T.; Granite, E.J.

2009-05-01T23:59:59.000Z

402

Indoor Mold, Toxigenic Fungi, and Stachybotrys chartarum: Infectious Disease Perspective  

Science Journals Connector (OSTI)

...other substrates including pipe insulation, gypsum, fiberglass wallpaper...Fungal colonization of fiberglass insulation in the air distribution system...associated with urea-formaldehyde foam insulation in Canada. Mycopathologia 99...

D. M. Kuhn; M. A. Ghannoum

2003-01-01T23:59:59.000Z

403

The mechanism of the formation and transformation of ettringite  

Science Journals Connector (OSTI)

The formation and transformation of ettringite were studied by measuring the ion concentration...3A, gypsum, lime and C?S?H gel on ettringite formation and transformation were also investigated. The ... compositi...

Peng Jiahui; Zhang Jianxin; Qu Jindong

2006-09-01T23:59:59.000Z

404

Ettringite and calcium sulfoaluminate cement: investigation of water content by near-infrared spectroscopy  

Science Journals Connector (OSTI)

Calcium sulfoaluminate (CSA) cement is a sulfate-based binder whose high-performance hydraulic behavior depends on the rapid formation of ettringite, when grinded clinker is hydrated in presence of gypsum. Ettringite

Daniela Gastaldi; Fulvio Canonico; Enrico Boccaleri

2009-11-01T23:59:59.000Z

405

TECHNICAL REPORT  

Office of Scientific and Technical Information (OSTI)

that use limestone as a scrubber for SOz and produce gypsum as a by-product, are advanced pollution control technologies that will remain preferred choices for Phase-I1 compliance...

406

The Crystal Chemistry of Zeolites  

Science Journals Connector (OSTI)

...LB (1971) New occurrence of yugawaralite from the Chena Hot Springs area, Alaska. Am Mineral 56:1699-1717 Effenberger...laumontite with quartz, thenardite, and gypsum at Sespe Hot Springs, western Transverse Ranges, California. Clays Clay...

E. Passaglia; Richard A. Sheppard

407

Urban Form Energy Use and Emissions in China: Preliminary Findings and Model Proof of Concept  

E-Print Network (OSTI)

producing building materials, but it does not include upstream requirements of energyenergy required for producing the water, limestone, sandstone, gypsum, and clay typically used for cement production. The building

Aden, Nathaniel

2011-01-01T23:59:59.000Z

408

Ion exchange-induced dissolution of calcite in Na-montmorillonite/CaCO?b3?s systems: its effect on hydraulic conductivity, CaCO?b3?s dissolution kinetics, and CaCO?b3?s equilibrium relations  

E-Print Network (OSTI)

of Ca- containing amendments such as gypsum, lime, CaC12, and phosphogypsum (Magdoff and Bresler, 1973; Oster and Frenkcl, 1980; Keren and Shainberg, 1981; Keren and O' Connor, 1982; Shainberg et al. , 1982; Kazman et al. , 1983 ); however, more... of Ca- containing amendments such as gypsum, lime, CaC12, and phosphogypsum (Magdoff and Bresler, 1973; Oster and Frenkcl, 1980; Keren and Shainberg, 1981; Keren and O' Connor, 1982; Shainberg et al. , 1982; Kazman et al. , 1983 ); however, more...

Del Rio Durand, Jose Bruno

2012-06-07T23:59:59.000Z

409

Superficies y Vacio 8, 104-108(1999) Sociedad Mexicana de Ciencias de Superficies y de Vaco. Fotorreflectancia y fotoluminiscencia de pelculas de ZnSe crecidas por MBE sobre  

E-Print Network (OSTI)

Se sobre GaAs. Uno de los problemas serios es el desacople de 0.27% que hay entre las redes del ZnSe y del

Meléndez Lira, Miguel Angel

410

Volume 138, number 6 CHEMICAL PHYSICSLETTERS 7 August1987  

E-Print Network (OSTI)

structure patterned using electron beam lithography SiO2 layer etched using CF4 and GaAs etched using Cl2

411

Profiling the Built-In Electrical Potential in III-V Multijunction Solar Cells (Poster)  

SciTech Connect

We have observed three electrical potentials at the top, tunneling, and bottom junctions of GnInP{sub 2}/GaAs tandem-junction solar cells, by performing the UHV-SKPM measurement. The effect of laser illumination was avoided by using GaAs laser with photon energy of 1.4 eV for the AFM operation. We also observed higher potentials at the atomic steps than on the terraces for both p-type GaInP{sub 2} epitaxial layer and p-type GaAs substrate, and found that the potential at steps of GaAs substrate depends on the step directions.

Jiang, C.-S.; Friedman, D. J.; Moutinho, H. R.; Al-Jassim, M. M.

2006-05-01T23:59:59.000Z

412

E-Print Network 3.0 - acute low-level microwave Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

of California at San Diego Collection: Engineering 5 2picosecond, GaAs photodiode optoelectronic circuit for optical correlation applications Summary: diode that serves as the...

413

E-Print Network 3.0 - antimony 133 Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

increases with the antimony molar fraction... boat with several compartments. The gallium solution contains GaAs for saturation and metallic antimony Source: Ecole...

414

E-Print Network 3.0 - absorption coefficient based Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

67 Optical nonlinearity in low-temperature-grown GaAs: Microscopic limitations and optimization strategies Summary: is the absorption coefficient, d the physical thickness of the...

415

E-Print Network 3.0 - approximate analytic approach Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

analytic channel potential for fully-depleted gate-all-around (GAA) MOSFETs with finite doping... body is presented. This model is derived from assumptions made for...

416

2070 OPTICS LETTERS / Vol. 29, No. 17 / September 1, 2004 400-photon-per-pulse ultrashort pulse autocorrelation  

E-Print Network (OSTI)

-photon absorption in silicon avalanche photodiodes,3 GaAs photomultiplier tubes,4 and InGaAsP laser diodes.5

Purdue University

417

E-Print Network 3.0 - advanced technology large-aperture Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

(Advanced Photonix). These diodes were chosen for two reasons. First... pulsed terahertz emitter, a large-aperture GaAs photoconductive switch, is carried out. It is...

418

Two-dimensional normal-state quantum oscillations in a superconducting heterostructure  

Science Journals Connector (OSTI)

... GaAs at T = 300?K. Solid State Commun. 63, 591–594 (1987)Saifi, M. A. & Cross, L. E. Dielectric properties of strontium titanate at ...

Y. Kozuka; M. Kim; C. Bell; B. G. Kim; Y. Hikita; H. Y. Hwang

2009-11-26T23:59:59.000Z

419

JOURNALDE PHYSIQUEIV Colloque C1, supplkmentau Journal de Physique 111,Volume 5,janvier 1995  

E-Print Network (OSTI)

that occur naturally in semi-insulating (SI) Gallium arsenide. The growth and assessment of SI Ga process which is by radiation and convection of heat from the crystal surface into the ambient. The former is uncontrolled as the radiation takes place into a cool chamber; the latter is controllable to an extent

Boyer, Edmond

420

Controls on the genesis of hydrothermal cobalt mineralization: insights from the mineralogy and geochemistry of the Bou Azzer deposits, Morocco  

E-Print Network (OSTI)

Controls on the genesis of hydrothermal cobalt mineralization: insights from the mineralogy,Ni,Fe) arsenides and sulpharsenides, with accessory sulphides and gold in a quartz-carbonate gangue. The ore-Ni-Fe, avec des quantités mineures de sulphures et de l'or dans une gangue de quartz- carbonate. Les minerais

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Friday, May 21, 2010 High-Performance Electronics without the High Price  

E-Print Network (OSTI)

materials. Researchers have used the method to make high-performance image sensors, transistors, and solar exotic semiconductors brings down the cost of high- performance solar cells and microchips. By Katherine Bourzac Compared to silicon, semiconductors like gallium arsenide can be made into solar cells

Rogers, John A.

422

e! Science News Semiconductor manufacturing technique holds  

E-Print Network (OSTI)

arsenide chips manufactured in multilayer stacks: light sensors, high-speed transistors and solar cellse! Science News Semiconductor manufacturing technique holds promise for solar energy Published semiconductor manufacturing method pioneered at the University of Illinois, the future of solar energy just got

Rogers, John A.

423

Phytochrome induces changes in the immunodetectable level of a wall peroxidase that precede growth changes in maize seedlings  

Science Journals Connector (OSTI)

...the 20-min distilled water rinse, the light-treated...with a 3 x 8 array of gallium aluminum arsenide infrared light (IR...loading and distilled water rinse. Sections were...the binding state or solubility of the peroxidase could...

Sung-Ha Kim; James R. Shinkle; Stanley J. Roux

1989-01-01T23:59:59.000Z

424

Corrosion of Electronic Materials and Devices  

Science Journals Connector (OSTI)

...ranging from silicon to gallium arsenide to mercury cadmium...protected against are water vapor and atmospheric...amount of adsorbed water on the surface...several monolayers of water are present on clean...reactivity with or solubility in the existing surface...

R. B. COMIZZOLI; R. P. FRANKENTHAL; P. C. MILNER; J. D. SINCLAIR

1986-10-17T23:59:59.000Z

425

Zone Melting  

Science Journals Connector (OSTI)

...four-turn induction coils of water-cooled copper tubing...by introducing a bit of water vapor into the hydrogen...apparatus (6). The water vapor combines with the...indium antimo-nide, gallium arsenide, gallium phos-phide...

W. G. Pfann

1962-03-30T23:59:59.000Z

426

Anomalous Properties of Poly(methyl methacrylate) Thin Films in Supercritical Carbon Dioxide  

Science Journals Connector (OSTI)

The PMMA swelling isotherms are insensitive to changing the substrate from silicon to gallium arsenide. ... The wafers were then rinsed with voluminous amounts of deionized water (NANOpureII, Barnstead) and then dried with nitrogen gas (Matheson Gas Products, >99.999%). ... The solubility of CO2 in the polymer film may be expected to decrease as the compressibility increases. ...

S. M. Sirard; K. J. Ziegler; I. C. Sanchez; P. F. Green; K. P. Johnston

2002-02-01T23:59:59.000Z

427

Initial stages of the autocatalytic oxidation of the InAs(0 0 1)-(4 2)/c(8 2) surface by molecular oxygen  

E-Print Network (OSTI)

by molecular oxygen Jonathon B. Clemens a , Sarah R. Bishop a , Darby L. Feldwinn a,1 , Ravi Droopad b,2 simulations Scanning tunneling microscopy Chemisorption Oxidation Indium arsenide Oxygen Semi conducting) surface by molecular oxygen (O2) were studied using scanning tunneling microscopy (STM) and density

Kummel, Andrew C.

428

VOLUME 84, NUMBER 18 P H Y S I C A L R E V I E W L E T T E R S 1 MAY 2000 Microscopic View of a Two-Dimensional Lattice-Gas Ising System  

E-Print Network (OSTI)

-Dimensional Lattice-Gas Ising System within the Grand Canonical Ensemble V. P. LaBella, D. W. Bullock, M. Anser, Z on the GaAs(001) surface and modeled as a lattice-gas Ising system. Without depositing any material, 2D Ga Ising system through the critical point and a complete Hamiltonian for modeling the GaAs(001) surface

Thibado, Paul M.

429

Method of making suspended thin-film semiconductor piezoelectric devices  

DOE Patents (OSTI)

A process for forming a very thin suspended layer of piezoelectric material of thickness less than 10 microns. The device is made from a combination of GaAs and AlGaAs layers to form either a sensor or an electronic filter. Onto a GaAs substrate is epitaxially deposited a thin (1-5 micron) sacrificial AlGaAs layer, followed by a thin GaAs top layer. In one embodiment the substrate is selectively etched away from below until the AlGaAs layer is reached. Then a second selective etch removes the sacrificial AlGaAs layer, that has acted here as an etch stop, leaving the thin suspended layer of piezoelectric GaAs. In another embodiment, a pattern of small openings is etched through the thin layer of GaAs on top of the device to expose the sacrificial AlGaAs layer. A second selective etch is done through these openings to remove the sacrificial AlGaAs layer, leaving the top GaAs layer suspended over the GaAs substrate. A novel etchant solution containing a surface tension reducing agent is utilized to remove the AlGaAs while preventing buildup of gas bubbles that would otherwise break the thin GaAs layer.

Casalnuovo, Stephen A. (Albuquerque, NM); Frye-Mason, Gregory C. (Cedar Crest, NM)

2001-01-01T23:59:59.000Z

430

Invited Paper GaAs/A1O photonic bandgap material fabrication and characterization  

E-Print Network (OSTI)

semiconductor crystals, photonic crystals do not occur naturally. There are, therefore, several seemingly direct bandgap semiconductors, such as GaAs, A1GaAs, InP, InGaAsP, etc., in which the radiative-dimensional photonic bandgaps for microwave and millimeter-wave radiation, and for shorter optical wavelengths in one

Zhou, Weidong

431

Modeling of InAs/GaAs Quantum Dot Solar Cells  

Science Journals Connector (OSTI)

This paper reports electrical characteristics of an intermediate band p-i-n GaAs solar cell with InAs quantum dots embedded in the intrinsic region using Synopsis TCAD simulation tools. Up to five layers of quantum dots have been taken into consideration ... Keywords: Quantum dots, Intermediate band, InAs, GaAs, Solar Cells, TCAD

Ayman Rizk; Kazi Islam; Ammar Nayfeh

2013-11-01T23:59:59.000Z

432

LAVAMAC Report LAser strobed Vacuum Assisted  

E-Print Network (OSTI)

Cathode thickness, p-doping,cathode material, light pulse intensity 0.1micron graded bandgap GaAs cathode limitations, detectors will have 10 ìm square active area and buffer region of 5 ìm. Detectors 10110110110011000010011011110100 200fsec light pulse 500fsec electron pulse 50nm GaAs Drift time of electrons inside cathode

Pease, R. Fabian W.

433

GALLIUM--2000 30.1 By Deborah A. Kramer  

E-Print Network (OSTI)

the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 63% of total consumption. Optoelectronic devices accounted for 32% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

434

GALLIUM--1998 29.1 By Deborah A. Kramer  

E-Print Network (OSTI)

's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes and light-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 45% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

435

GALLIUM--2003 28.1 References that include a section mark () are found in the Internet  

E-Print Network (OSTI)

in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic devices (LEDs, laser diodes, photodetectors, and solar cells) and ICs. ICs and optoelectronic devices each accounted for 41) and optoelectronic devices [mostly laser diodes and light- emitting diodes (LEDs)]. Estimated crude gallium

436

GALLIUM--1999 29.1 By Deborah A. Kramer  

E-Print Network (OSTI)

circuits (IC's) were the largest application for gallium, with optoelectronic devices [mostly laser diodes-use application for gallium, with 52% of total consumption. Optoelectronic devices accounted for 42% of domestic% of the gallium consumed in the United States was in the form of GaAs. GaAs was manufactured into optoelectronic

437

Resonant Raman scattering in an InAs/GaAs monolayer structure  

E-Print Network (OSTI)

), embedded in bulklike GaAs with two Al- GaAs cladding layers forming a waveguide. The InAs- mono- layer system used. Raman spectra were excited with a Ti-Sapphire laser, tuned from 1.41 eV to 1.435 e

Nabben, Reinhard

438

phys. stat. sol. (c) 0, No. 4, 11771180 (2003) / DOI 10.1002/pssc.200303033 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1610-1634/03/00007-1177 $ 17.50+.50/0  

E-Print Network (OSTI)

epitaxial structures and fully processed laser diodes against particle irradiation as compared to bulk and 2 of a GaAs substrate, the active layer together with GaAs cladding layers were placed between two Al techniques. The excita- tion was performed by a Ti:sapphire laser system including an OPO, with spectrally

Nabben, Reinhard

439

Monolithic high voltage nonlinear transmission line fabrication process  

DOE Patents (OSTI)

A process for fabricating sequential inductors and varistor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varistor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process. 6 figs.

Cooper, G.A.

1994-10-04T23:59:59.000Z

440

Monolithic high voltage nonlinear transmission line fabrication process  

DOE Patents (OSTI)

A process for fabricating sequential inductors and varactor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varactor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process.

Cooper, Gregory A. (346 Primrose Dr., Pleasant Hill, CA 94523)

1994-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Buildings Energy Data Book: 9.4 High Performance Buildings  

Buildings Energy Data Book (EERE)

4 4 Case Study, The Philip Merrill Environmental Center, Annapolis, Maryland (Office) Building Design Floor Area: 31,000 SF Floors: 2 Footprint: 220 ft. x (1) 2 Floors of open office space Attached pavilion containing: Meeting space Kitchen Staff dining Conference room Shell Windows U-Factor SHGC (2) Type: Double Pane, Low-e, Argon Filled Insulating Glass 0.244 0.41 Wall/Roof Material Effective R-Value Interior Wall plywood, gypsum, SIP foam, and sheathing 28.0 Exterior Wall gypsum and insulated metal framing 9.3 Roof plywood, gypsum, SIP foam, and sheathing 38.0 HVAC 18 ground source heat pumps fin and tube radiators connected to a propane boiler 1 air condtioning unit Lighting Power Densities (W/SF) First Floor: 1.2 Second Floor: 1.6 Conference Room: 1.4 Energy/Power PV System: 4.2 kW thin-film system

442

Macroscopic corrosion front computations of sulfate attack in sewer pipes based on a micro-macro reaction-diffusion model  

E-Print Network (OSTI)

We consider a two-scale reaction diffusion system able to capture the corrosion of concrete with sulfates. Our aim here is to define and compute two macroscopic corrosion indicators: typical pH drop and gypsum profiles. Mathematically, the system is coupled, endowed with micro-macro transmission conditions, and posed on two different spatially-separated scales: one microscopic (pore scale) and one macroscopic (sewer pipe scale). We use a logarithmic expression to compute values of pH from the volume averaged concentration of sulfuric acid which is obtained by resolving numerically the two-scale system (microscopic equations with direct feedback with the macroscopic diffusion of one of the reactants). Furthermore, we also evaluate the content of the main sulfatation reaction (corrosion) product---the gypsum---and point out numerically a persistent kink in gypsum's concentration profile. Finally, we illustrate numerically the position of the free boundary separating corroded from not-yet-corroded regions.

Chalupecký, Vladimír; Kruschwitz, Jens; Muntean, Adrian

2012-01-01T23:59:59.000Z

443

Achieving minimum impact insulation class 50 rating using resilient clip technology in lightweight construction.  

Science Journals Connector (OSTI)

Resilient clip technology is an alternative to resilient channel for supporting gypsum wallboard in fire rated wall and floor?ceiling assemblies. Lightweight wood frame construction presents challenges in meeting building code requirements for impact insulation class (IIC) and sound transmission class (STC) ratings in floor?ceiling assemblies. Through laboratory testing we were able to compare different floor?ceiling assemblies commonly used in multi?family construction. Two different structures were tested an 18 in. open web truss 24 in. o.c. and a 12 in. engineered joist (TJI) 24 in. o.c. Various finish floor coverings were used including ceramic tile vinyl and engineered wood. Structures achieved minimum IIC and STC 50 with and without 3/4 in. Gypsum concrete. Resilient rubber underlayment of varying thickness can further improve the IIC and STC ratings of the assembly as can adding a second layer of gypsum wallboard.

Wilson Byrick

2010-01-01T23:59:59.000Z

444

Profile NeutronDetector 9-16-04..pmd  

NLE Websites -- All DOE Office Websites (Extended Search)

GALLIUM ARSENIDE SEMICONDUCTOR-BASED GALLIUM ARSENIDE SEMICONDUCTOR-BASED NEUTRON DETECTOR B E N E F I T S Portable, Accurate Device Detects and Monitors Neutrons and Nuclear Materials * More accurate and sensitive than other technologies * Performance won't degrade over time * Easy implementation and deployment * Rugged, lightweight, and portable for field use * Reduces false readings * Requires less power * Low mass-production cost (about $1 per chip) * Neutron detection * Detecting and monitoring nuclear materials and weapons * Permanent installations and portable field operation * High-vacuum environments (e.g., physics labs and space platforms) An advanced neutron detector developed by Argonne National Laboratory and Kansas State University accurately detects neutrons and finds concealed nuclear weapons and materials, even in harsh or challenging environments. The key

445

Development of electrochemical photovoltaic cells. Third technical progress report, November 1, 1979-January 31, 1980  

SciTech Connect

The development of stable, efficient, electrochemical photovoltaic cells based on silicon and gallium arsenide in non-aqueous electrolyte systems is being investigated. The effect of surface condition of silicon electrodes on electrochemical and physical characteristics has been studied. An electrode-supporting electrolyte interaction in acetonitrile has been identified which leads to etching of the surface. Improved performance can result, which has practical significance. Gallium arsenide electrodes have been electrochemically characterized in cells containing propylene carbonate with a ferrocene/ferricenium redox additive. Degradation of the ferricenium salt under illumination has been investigated. Other redox couples studied to date have not given promising results. Long-term stability experiments have been deferred while a better understanding of electrode behavior is being obtained.

Byker, H.J.; Schwerzel, R.E.; Wood, V.E.; Austin, A.E.; Brooman, E.W.

1980-03-07T23:59:59.000Z

446

NEWTON, Ask a Scientist at Argonne National Labs  

NLE Websites -- All DOE Office Websites (Extended Search)

Mica, Gypsum, and Hardness Mica, Gypsum, and Hardness Name: Melissa Status: educator Grade: 4 Location: NC Country: USA Date: Winter 2011-2012 Question: I have a question regarding the hardness of mica and gypsum. Gypsum is a 2 on Moh's hardness scale and mica is somewhere between a 2 and 3. However, mica breaks and scratches very easily by a penny, paper clip, and fingernail and gypsum does not. What is a good way to explain to my students how gypsum is still "softer" on the scale? Obviously, mica breaks apart very easily. Replies: Melissa, Mineral hardness and mineral cleavage are separate issues. Mineral hardness is a measure of a mineral's ability to resist being scratched. Mineral cleavage is the ability for a mineral to split along weakly-bonded atomic planes. The micas have one good mineral cleavage. That is, mica splits nicely in along one plane. Halite (table salt), on the other hand, splits equally well in three orthogonal directions (that is, along three planes, each of which is at 90 degrees to the others). Shake out some table salt on an overhead projector and have the students walk up to the screen. They will see that all salt has cubic mineral cleavage. I don't know how much snow you get in North Carolina, but if you get some salt that is used to melt ice you will note that it too has cubic cleavage. When you break up the large salt crystals you will observe that they break into smaller cubes. When you break the mica, it will break into smaller sheets.

447

Thermionic-photovoltaic energy converter  

SciTech Connect

A thermionic-photovoltaic energy conversion device comprises a thermionic diode mounted within a hollow tubular photovoltaic converter. The thermionic diode maintains a cesium discharge for producing excited atoms that emit line radiation in the wavelength region of 850 nm to 890 nm. The photovoltaic converter is a silicon or galium arsenide photovoltaic cell having bandgap energies in this same wavelength region for optimum cell efficiency.

Chubb, D. L.

1985-07-09T23:59:59.000Z

448

Compositional Mapping of Self-Assembled Monolayers Derivatized within Microfluidic Networks  

Science Journals Connector (OSTI)

Carboxylic acid terminated self-assembled monolayers (SAMs) deposited on epitaxial gold substrates were activated in situ using a water-soluble carbodiimide and N-hydroxysuccinimide reagents. ... 20,32 The master template was available in our laboratory having been previously manufactured by exposing and developing a photoresist pattern on a gallium arsenide wafer. ... Images were obtained in lateral force and pulsed force modes using Topometrix silicon nitride (Si3N4) tips in air. ...

Steven J. Hinder; Simon D. Connell; Martyn C. Davies; Clive J. Roberts; Saul J. B. Tendler; Philip M. Williams

2002-03-19T23:59:59.000Z

449

Hard and Soft X-ray Absorption Spectroscopic Investigation of Aqueous Fe(III)?Hydroxamate Siderophore Complexes  

Science Journals Connector (OSTI)

19 The atmospheric pressure was maintained inside the sample chamber by placing a 0.16 ?m silicon nitride window between the sample chamber and upstream ultrahigh vacuum environment. ... The absorption spectra were recorded by detecting sample fluorescence (F) using a gallium arsenide photodiode (Hamamatsu Corporation). ... In aqueous solutions, the solubility of Fe(III) is extremely low close to neutral pH and the Fe(III) concentration increases in acidic and alkaline solutions (Figure 2). ...

David C. Edwards; Satish C. B. Myneni

2005-10-21T23:59:59.000Z

450

Imaging of semiconductors using a flying laser spot scanning system  

E-Print Network (OSTI)

be obsezved in the wavelength vs. absorption coefficient curves shown in Figure 1 for both a direct and an indirect semiconductor material (gallium-arsenide and silicon). It is only in the direct absorption and subsequent generation of a hole electron pair... in wavelength of light used to generate carriers pro- vides some contzol over the depth of the material analyzed. Long wavelength energy (- 1 micrometer) penetrates deeply into silicon, while gallium phosphide is considered almost transparent for a typical...

Richardson, Thomas William

2012-06-07T23:59:59.000Z

451

Block Copolymer Templated Chemistry for the Formation of Metallic Nanoparticle Arrays on Semiconductor Surfaces  

Science Journals Connector (OSTI)

One of key ingredients for many future applications is the ability to precisely pattern nanoscale features on technologically relevant semiconductor surfaces such as silicon and germanium, as well as compound semiconductors such as gallium arsenide and indium phosphide. ... Deposition of these metals is possible presumably due to the water solubility of their oxides:? Ge oxide,14c As oxide,24 and P oxide25 are soluble in water. ...

Masato Aizawa; Jillian M. Buriak

2007-09-25T23:59:59.000Z

452

Growth of ?-Amyloid(1?40) Protofibrils by Monomer Elongation and Lateral Association. Characterization of Distinct Products by Light Scattering and Atomic Force Microscopy  

Science Journals Connector (OSTI)

Soluble intermediates in A? fibrillogenesis, termed protofibrils, have been identified previously, and here we describe the in vitro formation and isolation of A?(1?40) protofibrils by size exclusion chromatography. ... Hydrodynamic radius (RH) measurements were made at room temperature with a DynaPro MSX instrument (Protein Solutions Inc., Charlottesville, VA) containing a gallium aluminum arsenide laser. ... The solubility of A?(1?43) in water was substantially decreased by addition of buffered NaCl (60). ...

Michael R. Nichols; Melissa A. Moss; Dana Kim Reed; Wen-Lang Lin; Rajendrani Mukhopadhyay; Jan H. Hoh; Terrone L. Rosenberry

2002-04-17T23:59:59.000Z

453

Nano-scale characterization of GaAsP/GaAs strained superlattice structure by nano-beam electron diffraction  

SciTech Connect

Distribution of lattice strain in a GaAsP/GaAs superlattice with a periodicity of 10?nm thickness, deposited on a 100?nm GaAs basal layer has been measured by nano-beam electron diffraction. The superlattice on the (001) plane of the basal GaAs layer shows a constant lattice strain from the bottom to the top layers, whereas the superlattice on the basal GaAs surface sloped by 16° from the (001) plane shows a variation of the lattice strain and crystal orientation. The difference of the strain distributions was discussed from the viewpoint of average strain. This tilt was explained by an atomistic model.

Jin, Xiuguang [Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Nakahara, Hirotaka [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Saitoh, Koh; Tanaka, Nobuo [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Takeda, Yoshikazu [Nagoya Industrial Science Research Institute, Nagoya 464-0819 (Japan); Aichi Synchrotron Radiation Center, Aichi Science and Technology Foundation, Seto 489-0965 (Japan)

2014-03-17T23:59:59.000Z

454

DEDALOS NREL: Cooperative Research and Development Final Report, CRADA Number CRD-07-237  

SciTech Connect

Currently High Concentration Photovoltaic (HCPV) terrestrial modules are based on the combination of optic elements that concentrate the sunlight into much smaller GaAs space cells to produce electricity. GaAs cell technology has been well developed for space applications during the last two decades, but the use of GaAs cells under concentrated sunlight in terrestrial applications leaves unanswered questions about performance, durability and reliability. The work to be performed under this CRADA will set the basis for the design of high-performance, durable and reliable HCPV terrestrial modules that will bring down electricity production costs in the next five years.

Friedman, D.

2013-06-01T23:59:59.000Z

455

Origin and paleogeography of an immense, nonmarine Miocene salt deposit in the Basin and Ranges (Western USA)  

E-Print Network (OSTI)

economic resources within continental rifts. They furnish strategic minerals (halite, gypsum, bo­ rates), storage capacity for natural gas and nuclear wastes (e.g., Johnson and Gonzales 1978; Dean and Johnson 1989), and effective seals for hydrocarbons... N Total Depth M Anhydrite-Gypsum Depthb (m) Halite Depthb (m) Halite Thickness0 M Dl Kerr-McGee #1 836 795 396 433 362 D2 Kerr-McGee # 2 859 651 444 459 192 D3 El Paso Natural Gas 855 1827 490 547 1280 D4 Tran Am Energy Co. 850 753 564...

Faulds, James; Schreiber, Charlotte; Reynolds, Stephen; Gonzá lez, Luis; Okaya, David

1997-01-01T23:59:59.000Z

456

Didcot B, launch platform for V94.3A  

SciTech Connect

National Power`s fourth combined cycle station at Didcot is now commissioning the first 660 MW block. But at the end of the year, the first examples of Siemens` advanced 240 MW gas turbine, Model V94.3A, will start simple cycle operation pending completion of the steam cycle. National Power`s clean-up strategy has seen emissions of SO{sub 2} and NO{sub x} halved, and CO{sub 2} emissions reduced by 30%. At Drax, a long-term contract with British Gypsum has ensured a market for the gypsum produced in the FGD unit to make plaster board. 3 figs., 1 tab.

NONE

1996-11-01T23:59:59.000Z

457

Chemical stabilization of three Texas Vertisols with sulfonated naphthalene  

E-Print Network (OSTI)

with lime, they may dissolve and react with lime to form other minerals that have adverse effects on stabilization. When gypsum is present in a soil to be treated with lime, ettringite may be produced and prohibit stabilization (Sabry et al. , 1981). Many... with lime, they may dissolve and react with lime to form other minerals that have adverse effects on stabilization. When gypsum is present in a soil to be treated with lime, ettringite may be produced and prohibit stabilization (Sabry et al. , 1981). Many...

Marquart, Darren Keith

2012-06-07T23:59:59.000Z

458

3D Modelling of Enhanced Surface Emission by Surface Roughening  

Science Journals Connector (OSTI)

3D FDTD is used to study the effect of surface roughening on the emission of a point source embedded in GaAs with a mirror behind the dipole. Enhancement factors of 10:1 are observed.

Buss, Ian J; Cryan, Martin J; Ho, Daniel; Craddock, Ian; Nash, Geoff; Haigh, Mary K; Railton, Chris; Rarity, John G

459

K.K. Gan TWEPP2007 1 Radiation-Hard Optical Link for SLHC  

E-Print Network (OSTI)

irradiation of GaAs PIN from 3 vendors: Optowell, AOC, ULM responsivities will be measured next month 0 2 4 vs Dosage AOC (5 & 10 Gb/s) might survive to SLHC dosage need further analysis after radiation cool

Gan, K. K.

460

E-Print Network 3.0 - ag thick film Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

on GaAs 110 only when... of many atomic layers, leading to the existence of a thickness window within which smooth metal films can... often depends on the film thickness. ......

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

E-Print Network 3.0 - atlas pulsed-power systems Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Tech University Lubbock, TX 79409-1051 Abstract Repetitive pulsed-power generators... simulation package, we have made a comparison of GaAs SIT and Si MOSFET-type switches for...

462

Solar to Chemical Energy Conversion with Photocatalytic Heterostructur...  

NLE Websites -- All DOE Office Websites (Extended Search)

greener and more sustainable alternative to other semiconductors such as GaAs, CdTe, CuInS2 (CIS), or CuInxGa1-xSe2 (CIGS). We recently synthesized anisotropic CZTS...

463

Fabrication of Molecular Devices  

E-Print Network (OSTI)

This project focuses on the synthesis and attachment of metal nanoparticles to Au and GaAs surfaces using a combination of chemical self-assembly and scanned probe lithography. In this project self-assembled monolayers (SAMs) of alkanethiols...

Walton, Katherine

2011-08-04T23:59:59.000Z

464

Hydrogen-bridge bonding on semiconductor surfaces:?Density-functional calculations  

Science Journals Connector (OSTI)

The relative stabilities of hydrogen bridge bonds on diamond C(001), Si(001), Ge(001), and GaAs(001) surfaces have been studied within the framework of density functional theory. Hydrogen-bridge bonds are found to be stable on cation terminated GaAs(001) and almost stable on p-type doped Si(001) surfaces with an excess energy of 0.08eV per bridge. Bridge bonds are unstable on n-type doped Si(001) and anion terminated GaAs(001). H-bridges are metastable on intrinsic group IV surfaces, and the excess energy cost diminishes monotonically across the C-Si-Ge series. In stark contrast with group IV semiconductors, the (2×1) monohydride dimer structure is not stable on GaAs(001).

J. M. Ripalda; J. D. Gale; T. S. Jones

2004-12-16T23:59:59.000Z

465

Monolithic heteroepitaxial integration of III-V semiconductor lasers on Si substrates  

E-Print Network (OSTI)

Monolithic optoelectronic integration on silicon-based integrated circuits has to date been limited to date by the large material differences between silicon (Si) and the direct-bandgap GaAs compounds from which optoelectronic ...

Groenert, Michael

2002-01-01T23:59:59.000Z

466

In-situ deposition of high-k dielectrics on III-V compound semiconductor in MOCVD system  

E-Print Network (OSTI)

In situ deposition of high-k materials to passivate the GaAs in metal organic chemical vapor deposition (MOCVD) system was well demonstrated. Both atomic layer deposition (ALD) and chemical vapor deposition (CVD) methods ...

Cheng, Cheng-Wei, Ph.D. Massachusetts Institute of Technology

2010-01-01T23:59:59.000Z

467

Ferromagnetic thin films  

DOE Patents (OSTI)

A ferromagnetic [delta]-Mn[sub 1[minus]x]Ga[sub x] thin film having perpendicular anisotropy is described which comprises: (a) a GaAs substrate, (b) a layer of undoped GaAs overlying said substrate and bonded thereto having a thickness ranging from about 50 to about 100 nanometers, (c) a layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] overlying said layer of undoped GaAs and bonded thereto having a thickness ranging from about 20 to about 30 nanometers, and (d) a layer of GaAs overlying said layer of [delta]-Mn[sub 1[minus]x]Ga[sub x] and bonded thereto having a thickness ranging from about 2 to about 5 nanometers, wherein x is 0.4[+-]0.05. 7 figures.

Krishnan, K.M.

1994-12-20T23:59:59.000Z

468

High-quality germanium photodiodes integrated on silicon substrates using optimized relaxed graded buffers  

E-Print Network (OSTI)

Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Received 22 for GaAs growth for fabricating light-emitting diodes LEDs , lasers, and solar cells on Si substrates. Ge

469

Second-order susceptibility from a tight-binding Hamiltonian  

E-Print Network (OSTI)

to calculate the energy dependence of X-(2)(omega) for GaAs. The results are in agreement with previous calculations and with available experimental data. [S0163-1829(98)01848-7]....

Dumitrica, T.; Graves, JS; Allen, Roland E.

1998-01-01T23:59:59.000Z

470

E-Print Network 3.0 - algaas mid infrared Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

processes in the mid-infrared. Bahram Jalali WILEY 20 Macmillan... Flexible optoelectronics PHOTOVOLTAICS of AlGaAs deposited on a GaAs wafer. The clever part of the scheme...

471

U.S. GEOLOGICAL SURVEY--MINERALS INFORMATION 1 By Deborah A. Kramer  

E-Print Network (OSTI)

). to produce optoelectronic devices and integrated circuits for Increased demand for GaAs resulted in several U. Consumption Optoelectronic devices continued to be the largest end use for gallium, with 59% of total

472

GaN quantum dot superlattices grown by molecular beam epitaxy at high temperature  

E-Print Network (OSTI)

P-based optoelectronic devices with Si microelectronic devices. This method uses a Au-Ge eutectic alloy as the bonding. The realization of integrafion of GaAs- and InP-based optoelectronic devices with Si microelectronic components

473

MANUSCRIPT PREPARATION TEMPLATE FOR THE 35TH IEEE PHOTOVOLTAIC...  

NLE Websites -- All DOE Office Websites (Extended Search)

FORM FACTOR GaAs SOLAR CELL Cruz-Campa, J. L. 1 ; Nielson, G. N. 1 ; Okandan, M. 1 ; Wanlass, M. W. 2 ; Sanchez, C. A. 1 ; Resnick. P. J. 1 ; Clews, P. J. 1 ; Pluym, T. 1 ;...

474

Exploring Self-Assembly and Photomechanical Switching Properties of Molecules at Surfaces  

E-Print Network (OSTI)

11.4 Self-Assembly Properties . . . . . . . . . . . . . 11.512.2 Self-Assembly of TTB-AB on GaAs(110) . . . . . . . 12.3at Surfaces 4 Self-Assembly Properties of Azobenzene on Au(

Cho, Jongweon

2010-01-01T23:59:59.000Z

475

E-Print Network 3.0 - ambichiral electro-optic structure Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

freely propagating continuous-wave terahertz radiation using electro-optic detection. The terahertz... -temperature-grown GaAs. This radiation is detected using the electro-optic...

476

Technical Session II Talks | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

.pdf file (6.2MB) GaAs Detector (Durbin) .pdf file (450KB) Advanced Neutron Detectors (Smith) .pdf file (818KB) Neutron Imaging System (Bingham) .pdf file (1.1MB) SR Advanced...

477

Status of the Kharkov Linac Polarized Electron Source  

Science Journals Connector (OSTI)

In this note we briefly describe the GaAs polarized electron source, which is the full-scale injector prototype for the electron linear accelerator of the Kharkov Institute of...

V. L. Agranovich; A. V. Glamazdin; V. G. Gorbenko…

1991-01-01T23:59:59.000Z

478

Wireless audio and burst communication link with directly modulated THz photoconductive antenna  

Science Journals Connector (OSTI)

We demonstrate transmission of audio and burst signals through a prototype THz analog communication link employing laser-gated low-temperature-grown GaAs dipole antenna as THz...

Liu, Tze-An; Lin, Gong-Ru; Chang, Yung-Cheng; Pan, Ci-Ling

2005-01-01T23:59:59.000Z

479

Nanopillar Photovoltaics: Photon Management and Junction Engineering for Next-Generation Solar Cells  

E-Print Network (OSTI)

S. Heterojunction photovoltaics using GaAs nanowires andC. M. Single nanowire photovoltaics, Chem. Soc. Rev. 38, 16-nanopillar-array photovoltaics on low-cost and flexible

Mariani, Giacomo

2013-01-01T23:59:59.000Z

480

February 24, 2009 Radiation-Hardness of VCSEL/PIN  

E-Print Network (OSTI)

Upgrade Week 6 Radiation-Hardness of GaAs PIN Preliminary Optowell AOC ULM significant decrease @ SLHC Gb/s Responsivity (A/W) GaAs Pre Post ULM 4.25 0.50 0.04 AOC 5.0 0.60 0.04 Optowell 3.125 0.60 0 8 850 nm VCSEL Power vs Dosage Very slow annealing of optical power AOC 5G has good power

Gan, K. K.

Note: This page contains sample records for the topic "arsenide gaas gypsum" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Published online 30 January 2007 Nucleic Acids Research, 2007, Vol. 35, No. 4 10751084 doi:10.1093/nar/gkl1140  

E-Print Network (OSTI)

understood. To follow the effects of (GAA)nÁ(TTC)n repeats on gene expres- sion, we have chosen E. coli of the full-sized mRNAs at (UUC)n runs by the E. coli degradosome. INTRODUCTION Friedreich's ataxia (FRDA.1093/nar/gkl1140 Effects of Friedreich's ataxia (GAA)nÁ(TTC)n repeats on RNA synthesis and stability Maria

Mirkin, Sergei

482

New GaInP/GaAs/GaInAs, Triple-Bandgap, Tandem Solar Cell for High-Efficiency Terrestrial Concentrator Systems  

SciTech Connect

GaInP/GaAs/GaInAs three-junction cells are grown in an inverted configuration on GaAs, allowing high quality growth of the lattice matched GaInP and GaAs layers before a grade is used for the 1-eV GaInAs layer. Using this approach an efficiency of 37.9% was demonstrated.

Kurtz, S.; Wanlass, M.; Kramer, C.; Young, M.; Geisz, J.; Ward, S.; Duda, A.; Moriarty, T.; Carapella, J.; Ahrenkiel, P.; Emery. K.; Jones, K.; Romero, M.; Kibbler, A.; Olson, J.; Friedman, D.; McMahon, W.; Ptak, A.

2005-11-01T23:59:59.000Z

483

JOURNAL DE PHYSIQUE Colloque C2, Suppl6ment au n06, Tome 49, juin 1988  

E-Print Network (OSTI)

-A GaAs wells and 100-A A10,8G~.7,As barriers. An A10.3Gao.,As cladding layer below the MQW structure serves to isolate the guiding region from the GaAs substrate. A 1-ym-thick A10.,,Gao.87As cladding layerAs/AlGaAs MQW materials. The dependence of the switching power on the laser wavelength was used to determine

Boyer, Edmond

484

Slide 1  

NLE Websites -- All DOE Office Websites (Extended Search)

Class 2400/1050/950 NGCC 11 90% Wet FGD / Econamine / Gypsum 10 Wet FGD / - / Gypsum Supercritical 3500/1100/1100 9 90% Wet FGD / Econamine / Gypsum 8 Wet FGD / - / Gypsum Subcritical 2400/1050/1050 PC 7 90% Selexol / Selexol / Claus 1800/1050/1050 IGCC 6 Sulfinol-M / - / Claus Shell 5 90% Selexol / Selexol / Claus 4 MDEA / - / Claus CoP E-Gas 3 90% Selexol / Selexol / Claus 2 Selexol / - / Claus GE F Class 1 CO 2 Cap Acid Gas Removal / CO 2 Separation / Sulfur Recovery Gasifier/ Boiler GT ST Cond. (psig/°F/°F) Plant Type Case GEE - GE Energy CoP - Conoco Phillips Carbon Sequestration Conference Presentation-May 8-11, 2006 5 Design Basis: Coal Type Illinois #6 Coal Ultimate Analysis (weight %) As Rec'd Dry Moisture 11.12 0 71.72 5.06 1.41 Chlorine 0.29 0.33 Sulfur 2.51 2.82 Ash 9.70 10.91 Oxygen (by difference) 6.88 7.75 100.0 100.0

485

Microsoft PowerPoint - Proceedings Cover Sheets  

NLE Websites -- All DOE Office Websites (Extended Search)

Class Class 2400/1050/950 NGCC 11 90% Wet FGD / Econamine / Gypsum 10 Wet FGD / - / Gypsum Supercritical 3500/1100/1100 9 90% Wet FGD / Econamine / Gypsum 8 Wet FGD / - / Gypsum Subcritical 2400/1050/1050 PC 7 90% Selexol / Selexol / Claus 1800/1050/1050 IGCC 6 Sulfinol-M / - / Claus Shell 5 90% Selexol / Selexol / Claus 4 MDEA / - / Claus CoP E-Gas 3 90% Selexol / Selexol / Claus 2 Selexol / - / Claus GE F Class 1 CO 2 Cap Acid Gas Removal/ CO 2 Separation / Sulfur Recovery Gasifier/ Boiler GT ST Cond. (psig/°F/°F) Plant Type Case GEE - GE Energy CoP - Conoco Phillips Carbon Sequestration Conference Presentation-May 8-11, 2006 5 Design Basis: Coal Type 13,126 11,666 HHV (Btu/lb) 100.0 100.0 7.75 6.88 Oxygen (by difference) 10.91 9.70 Ash 2.82 2.51 Sulfur 0.33 0.29 Chlorine 1.41 5.06 71.72 0 Dry 1.25 Nitrogen 4.50 Hydrogen 63.75 Carbon 11.12 Moisture

486

Energy and Buildings 70 (2014) 135144 Contents lists available at ScienceDirect  

E-Print Network (OSTI)

s t r a c t We have added expanded vermiculite and polypropylene fibers with low thermal conductivity were improved by the addition of expanded silica gel granules introduced into the gypsum [8]. Also://www.unt.edu/LAPOM (W. Brostow). 1 Tel.: +1 940 565 4358; fax: +1 940 565 4824. fiber, polyamide fiber, polyester fiber

North Texas, University of

487

Optical properties of the Dead Sea Emmanuel Boss,1  

E-Print Network (OSTI)

has been precipitating salts, in particular NaCl [Anati, 1993; Stiller et al., 1997]. Due to selective, 1983; Anati, 1993; Gavrieli, 1997; Stiller et al., 1997]. In addition, Gavrieli [1997] (and references therein) and Stiller et al. [1997] reported observations of suspended crystals of gypsum and aragonite

Boss, Emmanuel S.

488

2001 by the Arizona Board of Regents on behalf of the University of Arizona Near East Chronology: Archaeology and Environment. RADIOCARBON, Vol 43, Nr 3, 2001, p 11791189  

E-Print Network (OSTI)

with respect to salt and gypsum (Neev and Emery 1967; Stiller et al. 1997). The water has a wide range of inorganic radiocarbon composition (Stiller et al. 1988; Talma et al. 1997). Runoff water often formed a less have also occurred naturally in the past (Stiller and Chung 1984) inducing changes in the bottom lake

Yehouda, Enzel

489

Sedimentation characteristics of two commercial bentonites in aqueous suspensions  

Science Journals Connector (OSTI)

...rate for Tixoton under acid conditions was much smaller...gypsum, polyacrylamide, polyacrylic and sodium carboxymethyl...suspension can act as a dispersant or as a flocculant depending...relative to untreated clay. Acid and alkaline solutions...samples in the presence of acid are given in Fig. 5...

S. AKTHER; J. HWANG; H. LEE

490

THE FOURTEENTH ANNUAL MEETING OF THE PACIFIC DIVISION  

Science Journals Connector (OSTI)

...Bahrs reported that growth-promoting power of rabbit digestive mucosa for Planaria...H2SO4, gypsum, CaCl2 and FeSO4. W. L. Powers reported good progress in replacing exchange...accumulation of N03-N in the soil; W. L. Powers and R. D. Lewis reported an increased...

J. Murray Luck

1930-09-12T23:59:59.000Z

491

GEOLOGY, August 2010 715 INTRODUCTION  

E-Print Network (OSTI)

tuff layers located directly below and within the Badenian halite units of the northern Carpathian Poland are 30­100 m thick and consist of Ca-sulfates (anhydrite and gypsum) or halite with interca and the central parts of the Carpathian foredeep and its foreland. Halite is limited to a small area along

Utrecht, Universiteit

492

Calcium pumping and anhydrite/halite relationships in Silurian A unit of Michigan basin  

SciTech Connect

Observed relationships between anhydrite and halite in the A unit of the Michigan basin are not easily explained by classical evaporite depositional models. Within the Northern Reef trend, productive Niagaran pinnacle reefs are surrounded by A unit halite, which commonly exceeds 100 m in total thickness. However, A unit evaporites consist of thick anhydrite deposits on reef flanks and above reefs in the A-1 and A-2, respectively, Stratigraphic data suggest that the anhydrites surrounding reefs are contemporaneous with off-reef halite deposits. This reef-evaporite relationship poses three problems. (1) Why would gypsum precipitate from a halite-saturated brine (2) Why are anhydrites associated with the reefs (3) Why are anhydrites significantly thicker than predicted by evaporation models In a normal marine evaporation sequence (Hardie-Eugster model), gypsum is deposited from a brine until calcium is depleted. Upon further evaporation, the resultant halite-saturated brine would precipitate gypsum only in contact with a calcium source. The authors propose a calcium pumping mechanism whereby calcium-rich water associated with pinnacle reefs is responsible for gypsum precipitation around these reefs contemporaneous with off-reef halite. The additional supply of calcium also explains the anomalous thickness of these anhydrite deposits. Similar anhydrite halos around pinnacle reefs have been observed in the Devonian Elk Point basin.

Leibold, A.W.; Howell, P.D.

1989-03-01T23:59:59.000Z

493

The stable isotope composition of halite and sulfate of hyperarid soils and its relation to aqueous transport  

E-Print Network (OSTI)

The stable isotope composition of halite and sulfate of hyperarid soils and its relation to aqueous Halite (NaCl) and gypsum or anhydrite (CaSO4) are water-soluble minerals found in soils of the driest) and halite (NaCl). For both of these salts, there are long standing questions about the sources

Heimsath, Arjun M.

494

Journal of Sedimentary Research, 2012, v. 82, 9911005 Research Article  

E-Print Network (OSTI)

. The study of two late Miocene evaporite successions (one halite and the other gypsum) consisting of annual and halite deposits with a volume of more than 1 3 106 km3 (Hsu¨ et al. 1978; Montadert et al. 1978; Rouchy

Scafetta, Nicola

495

Heterogeneous chemistry of atmospheric mineral dust particles and their resulting cloud-nucleation properties  

E-Print Network (OSTI)

2 O), as well as soluble halite (NaCl) salts (Jeong, 2008;2 O), as well as soluble halite (NaCl) salts (Jeong, 2008;source as minerals such as halite (NaCl) and gypsum (CaSO

Sullivan, Ryan Christopher

2008-01-01T23:59:59.000Z

496

Basics of Mineralogy Geology 200  

E-Print Network (OSTI)

: Isometric - diamond, garnet, halite, pyrite Hexagonal - quartz, calcite, dolomite Tetragonal - not common or halite, fluorite Carbonates - calcite, dolomite Sulfates - gypsum, anhydrite Silicates - quartz, biotite element #12;Halite -- an example of a halide mineral #12;Anhydrite -- example of a sulfate mineral #12

Kammer, Thomas

497

The Most Significant Process in AridThe Most Significant Process in Arid Landscapes is theLandscapes is the AccumulationAccumulation ofof  

E-Print Network (OSTI)

,,......)) ·· ChloridesChlorides (halite)(halite) ·· Nitrates,Nitrates, IodatesIodates,, Chromates,Chromates, Borates), halite, borate, etc.Gypsum (other sulfates), halite, borate, etc. CaCa+2+2 + H+ H22O +O + SOSO44 Ca

Ahmad, Sajjad

498

Evaporite karst in the rolling plains and High Plains of Texas--Process and petrographic evidence  

SciTech Connect

Permian halite and anhydrite have been extensively dissolved by ground water in the shallow subsurface of the Texas Panhandle. Large caves in halite have collapsed, producing breccia chimneys. In contrast, stratiform halite dissolution has resulted in passive letdown of overlying beds. Residues left after halite dissolution can be identified by wavy lamination formed by top-to-bottom accretion and by distinctive limpid, multifaceted dolomite. In the deeper, more saline parts of the dissolution zone, anhydrite has been replaced volume-for-volume by gypsum, causing large amounts of calcium sulfate to be released. This regime is dominated by gypsum precipitation forming pore-filling cements and fibrous veins along fractures caused by salt dissolution. In the more flushed parts of the dissolution zone, gypsum is dissolved, further enhancing permeability. Paleo-dissolution horizons can be identified because (1) they are discordant with the active dissolution zone, demonstrating that they formed at times of lower topographic relief and (2) they are marked by silicification and calcitization of gypsum. Evaporite dissolution has a negative impact on water quality, and better understanding of dissolution processes has implications for design of remediation projects to decrease natural brine discharge into ground-water supplies.

Hovorka, S.D. (Univ of Texas, Austin, TX (United States). Bureau of Economic Geology)

1993-02-01T23:59:59.000Z

499

Isotope and trace element evolution of the Naica aquifer (Chihuahua, Mexico) over the past 60,000 yr revealed by speleothems  

Science Journals Connector (OSTI)

Abstract The “espada” speleothems of Cueva de las Espadas (Naica Mine, Chihuahua, Mexico) comprise a high-purity selenite core overlain by successive deposits of calcite, gypsum and aragonite. Gypsum precipitated under water from a hydrothermal solution (~ 58°C) when the water table was above the cave level ca. 57 ka, during the last glaciation, and some intervals during deglaciation and the Holocene. Aragonite was deposited at lower temperatures (~ 26°C) in a perched lake occupying the cave bottom, when the water table dropped below the cave level during brief dry intervals during deglaciation and the early Holocene. The isotopic composition of gypsum water of crystallization shows that the deglaciation–Holocene aquifer water was enriched in deuterium by 12.8–8.7‰ relative to water from the last glaciation. This is attributed to an increased relative moisture contribution from the Gulf of Mexico during deglaciation and the Holocene compared to the last glaciation. This indicates that drier conditions occurred in the Naica area during the Holocene than around 57 ka. Furthermore, trace element analyses of gypsum served to deduce the circulation regime of the Naica aquifer during the past 60,000 yr, and also suggest that higher aquifer recharge occurred during the last glaciation.

Fernando Gázquez; José-María Calaforra; Heather Stoll; Laura Sanna; Paolo Forti; Stein-Erik Lauritzen; Antonio Delgado; Fernando Rull; Jesús Martínez-Frías

2013-01-01T23:59:59.000Z

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Experimental study of reactions between ozone and building products M. Nicolas, O. Ramalho, F. Maupetit*  

E-Print Network (OSTI)

ozone and building products and document their potential impact on indoor air quality. PreliminaryExperimental study of reactions between ozone and building products M. Nicolas, O. Ramalho, F experiments were conducted on four building products: two carpets, a gypsum board and a pine wood board

Paris-Sud XI, Université de