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1

Oxidation of gallium arsenide  

DOE Patents (OSTI)

This invention relates to gallium arsenide semiconductors and, more particularly, to the oxidation of surface layers of gallium arsenide semiconductors for semiconductor device fabrication.

Hoffbauer, M.A.; Cross, J.B.

1991-11-16T23:59:59.000Z

2

Effects of asymmetry on electron spin dynamics in gallium arsenide quantum wells.  

E-Print Network (OSTI)

??This work presents optical studies of electron spin dynamics in gallium arsenide (GaAs) quantum wells, focusing on the effect of inversion asymmetric confinement potentials on… (more)

Eldridge, Peter Stephen

2009-01-01T23:59:59.000Z

3

Single event upsets in gallium arsenide dynamic logic  

SciTech Connect

The advantages and disadvantages of using gallium arsenide (GaAs) dynamic logic in computers and digital systems are briefly discussed, especially with respect to space applications. A short introduction to the topology and operation of GaAs Two-Phase Dynamic FET Logic (TDFL) circuits is presented. Experiments for testing the SEU sensitivity of GaAs TDFL, using a laser to create charge collection events, are described. Results are used to estimate the heavy-ion, soft error rate for TDFL in a spacecraft in geosynchronous orbit, and the dependence of the SEU sensitivity on clock frequency, clock voltage, and clock phase. Analysis of the data includes a comparison between the SEU sensitivities of TDFL and the more common static form of GaAs logic, Directly Coupled FET Logic (DCFL). This is the first reported SEU testing of GaAs dynamic logic.

Fouts, D.J. (Naval Postgraduate School, Monterey, CA (United States). ECE Dept.); Weatherford, T. (SFA Inc., Landover, MD (United States)); McMorrow, C.; Melinger, J.S.; Campbell, A.B. (Naval Research Lab., Washington, DC (United States))

1994-12-01T23:59:59.000Z

4

Coated gallium arsenide neutron detectors : results of characterizationmeasurements.  

DOE Green Energy (OSTI)

Effective detection of special nuclear materials (SNM) is essential for reducing the threat associated with stolen or improvised nuclear devices. Passive radiation detection technologies are primarily based on gamma-ray detection and subsequent isotope identification or neutron detection (specific to neutron sources and SNM). One major effort supported by the Department of Homeland Security in the area of advanced passive detection is handheld or portable neutron detectors for search and localization tasks in emergency response and interdiction settings. A successful SNM search detector will not only be able to confirm the presence of fissionable materials but also establish the location of the source in as short of time as possible while trying to minimize false alarms due to varying background or naturally occurring radioactive materials (NORM). For instruments based on neutron detectors, this translates to detecting neutrons from spontaneous fission or alpha-n reactions and being able to determine the direction of the source (or localizing the source through subsequent measurements). Polyethylene-coated gallium arsenide detectors were studied because the detection scheme is based on measuring the signal in the gallium arsenide wafers from the electrical charge of the recoil protons produced from the scattering of neutrons from the hydrogen nucleus. The inherent reaction has a directional dependence because the neutron and hydrogen nucleus have equivalent masses. The assessment and measurement of polyethylene-coated gallium arsenide detector properties and characteristics was the first phase of a project being performed for the Department of Homeland Security and the results of these tests are reported in this report. The ultimate goal of the project was to develop a man-portable neutron detection system that has the ability to determine the direction of the source from the detector. The efficiency of GaAs detectors for different sizes of polyethylene layers and different angles between the detector and the neutron source were determined. Preliminary measurements with a neutron generator based on a deuterium-tritium reaction ({approx}14 MeV neutrons) were performed and the results are discussed. This report presents the results of these measurements in terms of efficiency and angular efficiency and compares them to Monte Carlo calculations to validate the calculation scheme in view of further applications. Based on the results of this study, the polyethylene-coated gallium arsenide detectors provide adequate angular resolution based on proton recoil detection from the neutron scattering reaction from hydrogen. However, the intrinsic efficiency for an individual detector is extremely low. Because of this low efficiency, large surface area detectors ( or a large total surface area from many small detectors) would be required to generate adequate statistics to perform directional detection in near-real time. Large surface areas could be created by stacking the detector wafers with only a negligible attenuation of source neutrons. However, the cost of creating such a large array of GaAs is cost-prohibitive at this time.

Klann, R. T.; Perret, G.; Sanders, J.

2006-09-29T23:59:59.000Z

5

Single event upsets in gallium arsenide pseudo-complementary MESFET logic  

SciTech Connect

An introduction to gallium arsenide (GaAs) Pseudo-Complementary MESFET Logic (PCML) circuits is presented. PCML was developed to reduce the sensitivity of high-speed GaAs logic to radiation-induced single event upsets (SEUs). Experiments for testing the single-event upset (SEU) sensitivity of GaAs PCML integrated circuits (ICs) are described. The results of the experiments are analyzed. This new type of high-speed, low-power, GaAs logic provides decreased sensitivity to SEUs compared to more traditional circuit designs such as Directly-Coupled FET Logic (DCFL). PCML is fully compatible with existing GaAs E/D MESFET fabrication processes, such as those commonly used to make DCFL.

Fouts, D.J.; Wolfe, K.; Van Dyk, S.E. [Naval Postgraduate School, Monterey, CA (United States). Dept. of Electrical and Computer Engineering; Weatherford, T.R. [SFA Inc., Landover, MD (United States); McMorrow, D.; Melinger, J.S.; Tran, L.H.; Campbell, A.B. [Naval Research Lab., Washington, DC (United States)

1995-12-01T23:59:59.000Z

6

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

7

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 an 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 diffused layer and the substrate layer, wherein the n-type layer comprises a substantially low doping carrier concentration.

Hogan, Stephen J. (Golden, CO)

1986-01-01T23:59:59.000Z

8

Method for improving the growth of cadmium telluride on a gallium arsenide substrate  

DOE Patents (OSTI)

A method for preparing a gallium arsenide substrate, prior to growing a layer of cadmium telluride on a support surface thereof. The preparation includes the steps of cleaning the gallium arsenide substrate and thereafter forming prepatterned shapes on the support surface of the gallium arsenide substrate. The layer of cadmium telluride then grown on the prepared substrate results in dislocation densities of approximately 1{times}10{sup 6}/cm{sup 2} or less. The prepatterned shapes on the support surface of the gallium arsenide substrate are formed by reactive ion etching an original outer surface of the gallium arsenide substrate and into the body of the gallium arsenide substrate to a depth of at least two microns. The prepatterned shapes have the appearance of cylindrical mesas each having a diameter of at lease twelve microns. After the mesas are formed on the support surface of the gallium arsenide substrate, the substrate is again cleaned.

Reno, J.L.

1990-12-31T23:59:59.000Z

9

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

10

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

11

TESLA-FEL 2007-03 Application of low cost GaAs LED as neutron  

E-Print Network (OSTI)

neutrons in unbiased Gallium Arsenide (GaAs) Light Emitting Diodes (LED) resulted in a reduction Keywords: COTS components, Displacement damage, Electron Linear Accelerator, GaAs Light emitting diode (LED) Gallium Arsenide (GaAs) light emitting diode (LED) for the assessment of integrated neutron fluence

12

Thin film gallium arsenide solar cell research. Third quarterly project report, September 1, 1980-November 30, 1980. [Antireflection coating  

DOE Green Energy (OSTI)

The major objective of this contract is to produce gallium arsenide solar cells of 10% conversion efficiency in films of less than 10 micrometers thick which have been deposited by chemical vapor deposition on graphite or tungsten coated graphite substrates. Major efforts during this quarter were directed to: (1) the optimization of the deposition of gallium arsenide films of 10 ..mu..m thickness or less on tungsten/graphic substrates, (2) the investigation of the effectiveness of various grain boundary passivation techniques, (3) the deposition of tantalum pentoxide by ion beam sputtering as an antireflection coating, (4) the deposition of gallium aluminium arsenide by the organometallic process, and (5) the fabrication and characterization of large area Schottky barrier type solar cells from gallium arsenide films of about 10 ..mu..m thickness. Various grain boundary passivation techniques, such as the anodic oxidation, thermal oxidation, and ruthenium treatment, have been investigated. The combination of thermal oxidation and ruthenium treatment has been used to fabricate Schottky barrier type solar cells. Large area MOS solar cells of 9 cm/sup 2/ area with AMl efficiency of 8.5% have been fabricated from ruthenium treated gallium arsenide films of 10 ..mu..m thickness. The construction of the apparatus for the deposition of gallium aluminum arsenide by the organometallic process has been completed. The deposition of good quality tantalum pentoxide film as an antireflection coating has been carried out by the ion beam sputtering technique. The short-circuit current density and AMl efficiency of the solar cells are increased by approximately 60%, with a slight increase in the open-circuit voltage. Details are presented. (WHK)

Chu, S. S.

1980-12-01T23:59:59.000Z

13

Gallium arsenide thin films on tungsten/graphite substrates. Phase II. Quarterly project report No. 2, December 1, 1977-February 28, 1978  

DOE Green Energy (OSTI)

The objectives of this contract are to investigate thin films of gallium arsenide on tungsten/graphite substrates and to prepare solar cells with an AM1 efficiency of 6% or higher by August 1978. Efforts during this quarter have been directed to: (1) the deposition and characterization of gallium arsenide films on tungsten/graphite substrates by the arsenic and arsine processes, (2) the construction and operation of an apparatus for the deposition of titanium dioxide films, and (3) the fabrication and evaluation of MOS solar cells on tungsten/graphite substrates. Gallium arsenide films have been deposited on tungsten/graphite substrates by the reaction of gallium, hydrogen chloride, and arsenic in a hydrogen flow. The structural and electrical properties of these films are very similar to those obtained by the arsine process. The initial stage of the deposition of gallium arsenide films on tungsten/graphite substrates has been investigated by the scanning electron microscopy.

Chu, S.S.

1978-03-01T23:59:59.000Z

14

Dynamics of formation of photoresponse in a detector structure made of gallium arsenide  

SciTech Connect

The influence of capture effects on the characteristics of detectors of the ionizing radiation based on semi-insulating gallium arsenide is considered. Generation of nonequilibrium electrons and holes along the entire thickness of the active region was performed under illumination with an infrared light-emitting diode with a wavelength of 0.9 {mu}m. In this case, the situation emerging in the device structure under the effect of X-ray radiation or a high-energy electron beam was simulated. It is shown that the variation in the shape of the output signal with time in this case is caused by variation in the electric field profile due to the capture of holes at deep centers in gallium arsenide. An absolutely different distribution of the electric field emerges in the structure under irradiation of a semitransparent cathode of the structure with a red light-emitting diode, emission of which penetrates into the active region for mere 1 {mu}m. In this case, the transformation of the electric field is caused by the capture of electrons. Under the prolonged effect of such radiation, a space-charge-limited current mode emerges in the device.

Ayzenshtat, G. I., E-mail: ayzen@mail.tomsknet.ru; Lelekov, M. A.; Tolbanov, O. P. [Tomsk State University (Russian Federation)

2008-04-15T23:59:59.000Z

15

Monolithic series-connected gallium arsenide converter development  

DOE Green Energy (OSTI)

We report the development of monolithic GaAs photovoltaic devices intended to convert light generated by a laser or other bright source to electricity. The converters described here can provide higher operating voltage than is possible using a single-junction converter, owing to use of a monolithic circuit that forms a planar series-connected string of single-junction sub-cells. This planar monolithic circuit is arranged to deliver the desired voltage and current during operation at the maximum power point. The paper describes two-, six-, and twelve-junction converters intended for illumination by a laser diode with a wavelength of 0.8 {mu}m. Design and characterization data are presented for optical power in the range of 100 mW to 1 W. The best conversion efficiency exceeds 50%. 9 refs., 4 figs., 2 tabs.

Spitzer, M.B.; McClelland, R.W.; Dingle, B.D.; Dingle, J.E.; Hill, D.S. (Kopin Corp., Taunton, MA (United States)); Rose, B.H. (Sandia National Labs., Albuquerque, NM (United States))

1991-01-01T23:59:59.000Z

16

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

17

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

18

Selective growth experiments on gallium arsenide (100) surfaces patterned using UV-nanoimprint lithography  

Science Conference Proceedings (OSTI)

We describe a nanoimprint lithography (NIL) process and subsequent solid-source molecular beam epitaxy (SSMBE) growth of III-V semiconductors on patterned substrates. In particular, growth of GaAs, GaInAs, and GaInP, and effects of growth temperature ... Keywords: Molecular beam epitaxy, Nanoimprint lithography, Patterned substrates, Selective growth

A. Tukiainen; J. Viheriälä; T. Niemi; T. Rytkönen; J. Kontio; M. Pessa

2006-12-01T23:59:59.000Z

19

Gallium arsenide-based ternary compounds and multi-band-gap solar cell research  

DOE Green Energy (OSTI)

Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

Vernon, S. (Spire Corp., Bedford, MA (United States))

1993-02-01T23:59:59.000Z

20

Active devices for high temperature microcircuitry. [Silicon and gallium arsenide devices  

DOE Green Energy (OSTI)

As part of a program to develop high temperature electronics for geothermal well instrumentation, a number of solid state diode and transistor types were characterized from room temperature to 300/sup 0/C. The temperature dependence and aging stability of transport and leakage properties were measured. Included in the study were silicon diodes, bipolar transistors, JFETs, MOSFETs, and GaAs MESFETs and JFETs. In summary the results are: diodes and bipolar transistors became extremely leaky at high temperature and are therefore of limited use; silicon MOSFETs and GaAs devices showed unacceptable aging instabilities at high temperatures; silicon JFETs from certain manufacturers were sufficiently stable and had suitable temperature dependent characteristics so that operational circuits could be made. Comparisons were made of experimental device characteristics and those predicted by theory. The theoretical calculations were done using standard equations revised to include appropriate temperature dependent parameters. Close agreement between theory and experiment was found, indicating that unexpected high temperature effects were insignificant. In order to facilitate the use of devices in high temperature hybrids, it was necessary to develop bonding and prescreening techniques. A large variance of JFET 300/sup 0/C operating parameters was found even within a single production lot. Consequently, high temperature prescreening allowed each circuit to be specifically ''pretuned.'' Standard solder, epoxy, and chip and wire attachment technologies were not functional at 300/sup 0/C. Gold-germanium solder, aluminum wire to DuPont 9910 gold film, and diffusion barrier pads were developed to allow high temperature attachment.

Palmer, D.W.; Draper, B.L.; McBrayer, J.D.; White, K.R.

1978-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Thin films of gallium arsenide on low-cost substrates. Quarterly technical progress report No. 8 and topical report No. 3, April 2-July 1, 1978  

DOE Green Energy (OSTI)

The seventh quarter of work on the contract is summarized. The metalorganic chemical vapor deposition (MO-CVD) technique has been applied to the growth of thin films of GaAs and GaAlAs on inexpensive polycrystalline or amorphous substrate materials (primarily glasses and metals) for use in fabrication of large-area low-cost photovoltaic device structures. Trimethylgallium (TMG), arsine (AsH/sub 3/), and trimethylaluminum (TMAl) are mixed in appropriate concentrations at room temperature in the gaseous state and pyrolyzed at the substrate, which is heated in a vertical reactor chamber to temperatures of 725 to 750/sup 0/C, to produce the desired film composition and properties. The technical activities during the quarter were concentrated on (1) a continuing evaluation of various graphite materials as possible substrates for MO-CVD growith of the polycrystalline GaAs solar cells; (2) attempts to improve the quality (especially the grain size) of polycrystalline GaAs films on Mo sheet and Mo/glass substrates by using HCl vapor during the MO-CVD growith process; (3) further studies of the transport properties of polycrystalline GaAs films, wth emphasis on n-type films; (4) continuing investigations of the properties of p-n junctions in polycrystalline GaAs, with emphasis on the formation and properties of p/sup +//n/n/sup +/ deposited structures; and (5) assembling apparatus and establishing a suitable technique for producing TiO/sub 2/ layers for use as AR coatings on GaAs cells. Progress is reported. (WHK)

Ruth, R.P.; Dapkus, P.D.; Dupuis, R.D.; Johnson, R.E.; Manasevit, H.M.; Moudy, L.A.; Yang, J.J.; Yingling, R.D.

1978-07-01T23:59:59.000Z

22

Gallium arsenide-based ternary compounds and multi-band-gap solar cell research. Annual subcontract report, 15 April 1988--14 June 1990  

DOE Green Energy (OSTI)

Aim of this contract is the achievement of a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed is metalorganic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or may contain a p-n junction of its own and form the bottom cell of a two junction tandem solar cell structure. The III-V material for the single-junction case is GaAs and for the two-junction case is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include the following: (1) a 17.6% efficient GaAs-on-Si solar cell; (2) an 18.5% efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8% efficient GaAs-on-GaAs solar cell; (4) a 28.7% efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

Vernon, S. [Spire Corp., Bedford, MA (United States)

1993-02-01T23:59:59.000Z

23

A Study of the Activated GaAs Surface for Application as an Electron Source in Particle Accelerators  

Science Conference Proceedings (OSTI)

The use of type III-V semiconductor materials as photocathodes has in recent years become a focus for the High Energy Physics community. Once activated to a negative electron affinity (NEA) state and illuminated by a laser, these materials can be used as a high-brightness source of both polarised and un-polarised electrons in some modern accelerators, for example, ALICE (Accelerators and Lasers in Combined Experiments) at Daresbury Laboratory. This paper will focus on the use of gallium arsenide (GaAs) as a photocathode, and detail the reconfiguration and re-commissioning of two vacuum systems that support standard surface science techniques such as ultraviolet/X-ray photoelectron spectroscopy (UPS/XPS), low energy electron diffraction (LEED) and auger electron spectroscopy (AES). The paper will present details of cleaning GaAs in order to maximise quantum efficiency and will provide evidence from XPS and LEED to demonstrate what is happening at the atomic level.

Chanlek, N. [University of Manchester, Manchester, M13 9PL (United Kingdom); STFC Daresbury Laboratory, Warrington, WA4 4AD (United Kingdom); Herbert, J. D.; Jones, L. B.; Middleman, K. J. [STFC Daresbury Laboratory, Warrington, WA4 4AD (United Kingdom); Jones, R. M. [University of Manchester, Manchester, M13 9PL (United Kingdom)

2009-08-04T23:59:59.000Z

24

Gallium arsenide-based ternary compounds and multi-band-gap solar cell research. Final subcontract report, 1 April 1988--31 March 1990  

DOE Green Energy (OSTI)

This report describes work to achieve a high-efficiency, low-cost solar cell. The basic approach to the problem is centered upon the heteroepitaxial growth of a III-V compound material onto a single-crystal silicon wafer. The growth technique employed throughout this work is metal-organic chemical vapor deposition. The silicon wafer may serve as a mechanical substrate and ohmic contact for a single-junction device, or it may contain a p-n junction of its own and form the bottom cell of a two-junction tandem solar cell structure. The III-V material for the single-junction case is GaAs, and for the two-junction case it is either GaAlAs or GaAsP, either material having the proper composition to yield a band gap of approximately 1.7 eV. Results achieved in this contract include (1) a 17.6%-efficient GaAs-on-Si solar cell; (2) an 18.5%-efficient GaAs-on-Si concentrator solar cell at 400 suns; (3) a 24.8%-efficient GaAs-on-GaAs solar cell; (4) a 28.7%-efficient GaAs-on-GaAs concentrator solar cell at 200 suns; (5) the measurement of the effects of dislocation density and emitter doping on GaAs cells; and (6) improvements in the growth process to achieve reproducible thin AlGaAs window layers with low recombination velocities and environmental stability.

Vernon, S. [Spire Corp., Bedford, MA (United States)

1993-07-01T23:59:59.000Z

25

Rapid liquid phase epitaxial growth studies of GaAs: Final report, July 1984-June 1987  

Science Conference Proceedings (OSTI)

Single crystal layers of gallium arsenide have been grown on (111) and (100) oriented GaAs substrates from a flowing, GaAs saturated, gallium solution with a few degrees temperature differential across the liquid/solid interface. Very high growth rates, on the order of 8..mu..m per minute, have been observed. Such rates are in agreement with the growth theory developed as part of this program, and are about two orders greater than those typically achieved in conventional, static solution, liquid phase epitaxy. Both undoped and p-doped (Si) GaAs layers have been grown and some of their material properties measured. Good crystallinity was inferred from the narrowness of x-ray diffraction lines and from the intensities of the photoluminescence responses of all specimens sampled. While these results do not prove that the epi material is of photovoltaic quality, they indicate both a high crystallographic perfection and a low density of life-time poisoning impurities; conditions which are usually necessary for PV device development. Thus far, smooth surfaces have not been produced directly by the rapid liquid phase epitaxy (RLPE) process. The rough surface morphologies are due, at least in part, to incomplete wipe off of the liquid when the substrate is withdrawn at the end of the growth cycle. Another potential source is growth instabilities which will be discussed later. This report summarizes the three year research program of the RLPE process sponsored by DOE-SOLERAS.

Gerritsen, H.J.; Crisman, E.E.

1987-01-01T23:59:59.000Z

26

Heat load of a P-doped GaAs photocathode in SRF electron gun  

Science Conference Proceedings (OSTI)

Many efforts were made over the last decades to develop a better polarized electron source for the high energy physics. Several laboratories operate DC guns with the Gallium-Arsenide photo-cathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved using a Superconducting RF electron gun, which delivers beams of higher brightness than DC guns does, because the field gradient at the cathode is higher. SRF guns with metal cathodes and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since the cathode will be normal conducting, the problem about the heat load stemming from the cathode arises. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and the verification by measuring the quality factor of the gun with and without cathode.

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

2010-05-23T23:59:59.000Z

27

Single-Crystalline Thin Film Used in Photovoltaics  

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

Single-crystalline thin films are made from gallium arsenide (GaAs), a compound semiconductor that is a mixture of gallium and arsenic.

28

GALLIUM ARSENIDE SEMICONDUCTOR-BASED NEUTRON DETECTOR  

NEUTRON DETECTOR BENEFITS Portable, ... High Flux Isotope Reactor and Spallation Neutron Source. Several Homeland Security. LINKS TO ONLINE ...

29

Session B: Gallium Arsenide Processing Room: University Center ...  

Science Conference Proceedings (OSTI)

We report thin film InP based resonant tunneling diodes (RTD) and tunneling hot electron transfer amplifiers (THETA) contact bonded to silicon substates.

30

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

31

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

32

Doping of gallium nitride using disilane  

Science Conference Proceedings (OSTI)

Keywords: disilane, gallium nitride, metalorganic chemical vapor deposition, organometallic vapor phase epitaxy, silicon doping

A. E. Wickenden; L. B. Rowland; K. Doverspike; D. K. Gaskill; J. A. Freitas, Jr.; D. S. Simons; P. H. Chi

1995-11-01T23:59:59.000Z

33

Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits  

E-Print Network (OSTI)

New York Master of Science, Electrical Engineering (AppliedYork Bachelor of Science, Electrical Engineering RochesterElectronic Thin Film Science: For Electrical Engineers and

Bickford, Justin Robert

2008-01-01T23:59:59.000Z

34

Sparse gallium arsenide to silicon metal waferbonding for heterogeneous monolithic microwave integrated circuits  

E-Print Network (OSTI)

and V. I. Tsimbal, “Electrical Resistivity of Pd-In Alloys,”and V. I. Tsimbal, “Electrical Resistivity of Pd-In Alloys,”and V. I. Tsimbal, “Electrical Resistivity of Pd-In Alloys,”

Bickford, Justin Robert

2008-01-01T23:59:59.000Z

35

Gallium interactions with Zircaloy  

E-Print Network (OSTI)

High fluence ion implantation of Ga ions was conducted ics. on heated Zircaloy-4 in the range of [] Ga ions/[]. Surface effects were studied using SEM and electron microphone analysis. The depth profile of Ga in the Zircaloy was characterized with Rutherford backscattering and SIMS techniques. Results indicate that the Zirc-4 is little affected up to a fluency of [] Ga ions/[]. After implantation of [] Ga ions/[], sub-grain features on the order of 2 gm were observed which may be due to intermetallic compound formation between Ga and Zr. For the highest fluency implant, Ga content in the Zirc-4 reached a saturation value of between 30 and 40 atomic %; significant enhanced diffusion was observed but gallium was not seen to concentrate at grain boundaries.

West, Michael Keith

1998-01-01T23:59:59.000Z

36

Gallium Nitride nanowires: synthesis, contacts, electron ...  

Science Conference Proceedings (OSTI)

... Gallium Nitride nanowires: synthesis, contacts, electron transport, mechanical resonators, and defects. John E. Fischer University of Pennsylvania. ...

37

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

Science Conference Proceedings (OSTI)

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

38

Evaluation of critical materials for five advanced design photovoltaic cells with an assessment of indium and gallium  

DOE Green Energy (OSTI)

The objective of this study is to identify potential material supply constraints due to the large-scale deployment of five advanced photovoltaic (PV) cell designs, and to suggest strategies to reduce the impacts of these production capacity limitations and potential future material shortages. This report presents the results of the screening of the five following advanced PV cell designs: polycrystalline silicon, amorphous silicon, cadmium sulfide/copper sulfide frontwall, polycrystalline gallium arsenide MIS, and advanced concentrator-500X. Each of these five cells is screened individually assuming that they first come online in 1991, and that 25 GWe of peak capacity is online by the year 2000. A second computer screening assumes that each cell first comes online in 1991 and that each cell has 5 GWe of peak capacity by the year 2000, so that the total online cpacity for the five cells is 25 GWe. Based on a review of the preliminary basline screening results, suggestions were made for varying such parameters as the layer thickness, cell production processes, etc. The resulting PV cell characterizations were then screened again by the CMAP computer code. Earlier DOE sponsored work on the assessment of critical materials in PV cells conclusively identtified indium and gallium as warranting further investigation as to their availability. Therefore, this report includes a discussion of the future availability of gallium and indium. (WHK)

Watts, R.L.; Gurwell, W.E.; Jamieson, W.M.; Long, L.W.; Pawlewicz, W.T.; Smith, S.A.; Teeter, R.R.

1980-05-01T23:59:59.000Z

39

P-type gallium nitride  

DOE Patents (OSTI)

Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5{times}10{sup 11} /cm{sup 3} and hole mobilities of about 500 cm{sup 2} /V-sec, measured at 250 K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al. 9 figs.

Rubin, M.; Newman, N.; Fu, T.; Ross, J.; Chan, J.

1997-08-12T23:59:59.000Z

40

P-type gallium nitride  

DOE Patents (OSTI)

Several methods have been found to make p-type gallium nitride. P-type gallium nitride has long been sought for electronic devices. N-type gallium nitride is readily available. Discovery of p-type gallium nitride and the methods for making it will enable its use in ultraviolet and blue light-emitting diodes and lasers. pGaN will further enable blue photocathode elements to be made. Molecular beam epitaxy on substrates held at the proper temperatures, assisted by a nitrogen beam of the proper energy produced several types of p-type GaN with hole concentrations of about 5.times.10.sup.11 /cm.sup.3 and hole mobilities of about 500 cm.sup.2 /V-sec, measured at 250.degree. K. P-type GaN can be formed of unintentionally-doped material or can be doped with magnesium by diffusion, ion implantation, or co-evaporation. When applicable, the nitrogen can be substituted with other group III elements such as Al.

Rubin, Michael (Berkeley, CA); Newman, Nathan (Montara, CA); Fu, Tracy (Berkeley, CA); Ross, Jennifer (Pleasanton, CA); Chan, James (Berkeley, CA)

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Electrochemical Solution Growth: Gallium Nitride Crystal ...  

... and economical bulk gallium nirtide (GaN) substrates needed to meet the performance requirements of high-efficiency LED and high-power transistors.

42

Decreased gallium uptake in acute hematogenous osteomyelitis  

SciTech Connect

Decreased radiopharmaceutical uptake was noted on both bone and gallium scans in the case of acute hematogenous osteomyelitis of the right ilium (acetabular roof). This combination of findings is probably rare. The mechanism of decreased gallium uptake is unknown, but may be related to decreased blood flow.

Ang, J.G.; Gelfand, M.J.

1983-07-01T23:59:59.000Z

43

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

44

Bismuth in gallium arsenide: Structural and electronic properties of GaAs{sub 1-x}Bi{sub x} alloys  

Science Conference Proceedings (OSTI)

The structural and electronic properties of cubic GaAs{sub 1-x}Bi{sub x} alloys with bismuth concentration 0.0, 0.25, 0.50, 0.75 and 1.0 are studied using the 'special quasi-random structures' (SQS) approach of Zunger along with the generalized gradient approximation (GGA) and the Engel-Vosko generalized gradient approximation (EV-GGA). The lattice constant, bulk modulus, derivative of bulk modulus and energy gap vary with bismuth concentration nonlinearly. The present calculations show that the band gap decreases substantially with increasing bismuth concentration and that spin-orbit coupling influences the nature of bonding at high Bi concentrations. - Graphical abstract: Bowing effect of spin-orbit split-off band values versus Bi content with and without spin-orbit coupling for GaAs{sub 1-x}Bi{sub x} (at x=0.25, 0.50 and 0.75). Calculations are done with GGA. Highlights: Black-Right-Pointing-Pointer Structural and electronic properties of GaAs{sub 1-x}Bi{sub x} alloys were studied. Black-Right-Pointing-Pointer We present results of lattice constant, energy gap, bulk modulus and derivative. Black-Right-Pointing-Pointer The band gap decreases substantially with increasing Bi concentration. Black-Right-Pointing-Pointer Calculations of the density of states and charge densities are also presented. Black-Right-Pointing-Pointer We have performed calculations without and with spin-orbit coupling.

Reshak, Ali Hussain, E-mail: maalidph@yahoo.co.uk [School of Complex Systems, FFWP-South Bohemia University, Nove Hrady 37333 (Czech Republic); School of Material Engineering, Malaysia University of Perlis, P.O Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Kamarudin, H. [School of Material Engineering, Malaysia University of Perlis, P.O Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Auluck, S. [National Physical Laboratory Dr. KS Krishnan Marg, New Delhi 110012 (India); Kityk, I.V. [Electrical Engineering Department, Technological University of Czestochowa, Al. Armii Krajowej 17/19, Czestochowa (Poland)

2012-02-15T23:59:59.000Z

45

Characterizing organometallic-vapor-phase-epitaxy-grown indium gallium nitride islands on gallium nitride for light emitting diode applications.  

E-Print Network (OSTI)

??The indium-gallium-nitride on gallium-nitride (InGaN/GaN) materials system is a promising candidate for providing a high intensity, high efficiency solution to the yet unsolved problem of… (more)

Anderson, Kathy Perkins Jenkins

2011-01-01T23:59:59.000Z

46

Method for Plutonium-Gallium Separation by Anodic Dissolution of a Solid Plutonium-Gallium Alloy  

DOE Patents (OSTI)

Purified plutonium and gallium are efficiently recovered from a solid plutonium-gallium (Pu-Ga) alloy by using an electrorefining process. The solid Pu-Ga alloy is the cell anode, preferably placed in a moving basket within the electrolyte. As the surface of the Pu-Ga anode is depleted in plutonium by the electrotransport of the plutonium to a cathode, the temperature of the electrolyte is sufficient to liquify the surface, preferably at about 500 C, resulting in a liquid anode layer substantially comprised of gallium. The gallium drips from the liquified surface and is collected below the anode within the electrochemical cell. The transported plutonium is collected on the cathode surface and is recovered.

Miller, William E.; Tomczuk, Zygmunt

1998-12-08T23:59:59.000Z

47

Gallium-positive Lyme disease myocarditis  

Science Conference Proceedings (OSTI)

In the course of a work-up for fever of unknown origin associated with intermittent arrhythmias, a gallium scan was performed which revealed diffuse myocardial uptake. The diagnosis of Lyme disease myocarditis subsequently was confirmed by serologic titers. One month following recovery from the acute illness, the abnormal myocardial uptake completely resolved.

Alpert, L.I.; Welch, P.; Fisher, N.

1985-09-01T23:59:59.000Z

48

Solar cell with a gallium nitride electrode  

DOE Patents (OSTI)

A solar cell which comprises a body of silicon having a P-N junction therein with a transparent conducting N-type gallium nitride layer as an ohmic contact on the N-type side of the semiconductor exposed to solar radiation.

Pankove, Jacques I. (Princeton, NJ)

1979-01-01T23:59:59.000Z

49

Gallium 67 scintigraphy in glomerular disease  

Science Conference Proceedings (OSTI)

To evaluate the diagnostic usefulness of gallium 67 scintigraphy in glomerular disease, 45 patients with various glomerulopathies, excluding lupus nephritis and renal vasculitis, were studied. Persistent renal visualization 48 hours after the gallium injection, a positive scintigram, was graded as + (less than), ++ (equal to), and +++ (greater than) the hepatic uptake. Positive scintigrams were seen in ten of 16 cases of focal segmental glomerulosclerosis, six of 11 cases of proliferative glomerulonephritis, and one case of minimal change, and one of two cases of membranous nephropathy; also in three of six cases of sickle glomerulopathy, two cases of diabetic neuropathy, one of two cases of amyloidosis, and one case of mild chronic allograft rejection. The 25 patients with positive scans were younger than the 20 with negative scans (31 +/- 12 v 42 +/- 17 years; P less than 0.01), and exhibited greater proteinuria (8.19 +/- 7.96 v 2.9 +/- 2.3 S/d; P less than 0.01) and lower serum creatinine values (2 +/- 2 v 4.1 +/- 2.8 mg/dL; P less than 0.01). The amount of proteinuria correlated directly with the intensity grade of the gallium image (P less than 0.02), but there was no correlation between the biopsy diagnosis and the outcome of the gallium scan. It was concluded that gallium scintigraphy is not useful in the differential diagnosis of the glomerular diseases under discussion. Younger patients with good renal function and heavy proteinuria are likely to have a positive renal scintigram regardless of the underlying glomerulopathy.

Bakir, A.A.; Lopez-Majano, V.; Levy, P.S.; Rhee, H.L.; Dunea, G.

1988-12-01T23:59:59.000Z

50

Controlled VLS Growth of Indium, Gallium and Tin Oxide Nanowires via Chemical Vapor Transport  

E-Print Network (OSTI)

technique to synthesize indium oxide, gallium oxide, and tinmaterial systems such as indium oxide, gallium oxide and tinand Characterization A. Indium Oxide Nanowires Indium oxide

Johnson, M.C.; Aloni, S.; McCready, D.E.; Bourret-Courchesne, E.D.

2006-01-01T23:59:59.000Z

51

Survey of the market, supply and availability of gallium  

DOE Green Energy (OSTI)

The objective of this study was to assess the present consumption and supply of gallium, its potential availability in the satellite power system (SPS) implementation time frame, and commercial and new processing methods for increasing the production of gallium. Findings are reported in detail. The findings strongly suggest that with proper long range planning adequate gallium would be available from free-enterprise world supplies of bauxite for SPS implementation.

Rosi, F.D.

1980-07-01T23:59:59.000Z

52

Interactions of Zircaloy cladding with gallium: 1998 midyear status  

Science Conference Proceedings (OSTI)

A program has been implemented to evaluate the effect of gallium in mixed-oxide (MOX) fuel derived from weapons-grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in a light-water reactor. The graded, four-phase experimental program was designed to evaluate the performance of prototypic Zircaloy cladding materials against (1) liquid gallium (Phase 1), (2) various concentrations of Ga{sub 2}O{sub 3} (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of a series of tests for Phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement, and (3) corrosion-mechanical. These tests will determine corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in the mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at {ge}300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (parts per million) of gallium in the MOX fuel. Although continued migration of gallium into the initially formed intermetallic compound can result in large stresses that may lead to distortion, this was shown to be extremely unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed.

Wilson, D.F.; DiStefano, J.R.; Strizak, J.P.; King, J.F.; Manneschmidt, E.T.

1998-06-01T23:59:59.000Z

53

Interactions of zircaloy cladding with gallium -- 1997 status  

SciTech Connect

A four phase program has been implemented to evaluate the effect of gallium in mixed oxide (MOX) fuel derived from weapons grade (WG) plutonium on Zircaloy cladding performance. The objective is to demonstrate that low levels of gallium will not compromise the performance of the MOX fuel system in LWR. This graded, four phase experimental program will evaluate the performance of prototypic Zircaloy cladding materials against: (1) liquid gallium (Phase 1), (2) various concentrations of Ga{sub 2}O{sub 3} (Phase 2), (3) centrally heated surrogate fuel pellets with expected levels of gallium (Phase 3), and (4) centrally heated prototypic MOX fuel pellets (Phase 4). This status report describes the results of an initial series of tests for phases 1 and 2. Three types of tests are being performed: (1) corrosion, (2) liquid metal embrittlement (LME), and (3) corrosion mechanical. These tests are designed to determine the corrosion mechanisms, thresholds for temperature and concentration of gallium that may delineate behavioral regimes, and changes in mechanical properties of Zircaloy. Initial results have generally been favorable for the use of WG-MOX fuel. The MOX fuel cladding, Zircaloy, does react with gallium to form intermetallic compounds at {ge} 300 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (in parts per million) of gallium in the MOX fuel. While continued migration of gallium into the initially formed intermetallic compound results in large stresses that can lead to distortion, this is also highly unlikely because of the low mass of gallium or gallium oxide present and expected clad temperatures below 400 C. Furthermore, no evidence for grain boundary penetration by gallium has been observed.

Wilson, D.F.; DiStefano, J.R.; King, J.F.; Manneschmidt, E.T.; Strizak, J.P.

1997-11-01T23:59:59.000Z

54

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide...  

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

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward...

55

Gallium uptake by transferrin and interaction with receptor 1  

Science Conference Proceedings (OSTI)

Iron acquisition Á Gallium uptake Á Temperature-jump kinetics .... Part of this thera- peutic action is ..... are all considered as hard metals [10] and are com-.

56

Cold Atoms Could Replace Hot Gallium in Focused Ion ...  

Science Conference Proceedings (OSTI)

... The high energies needed to focus gallium for milling tasks end up burying small amounts in the sample, contaminating the material. ...

2011-04-26T23:59:59.000Z

57

Interactions of gallium with zircaloy cladding  

E-Print Network (OSTI)

A mastering system was constructed and installed on the current low energy accelerator of the Ion Beam Laboratory in the Department of Nuclear Engineering. Galium was implanted into heated zircaloy targets at nuances of 3x10¹?, 1x10¹? and 1x10¹? ions/cm². Rutherford backscattering spectrometry (RBS) using 260 keV alpha particles was used to determine the initial estimates of gallium concentration. Energy dispersive spectroscopy (EDS) and backscattered electron (BSE) imaging was performed to examine concentration and surface morphology, respectively. Zirconium was then implanted to simulate the radiation effects of fission fragments at a fluency of 1.0x10¹? Zr atoms/cm². RBS results showed enhanced diffusion and indicate saturation of the gallium concentration. Results also showed the possible formation of a Ga-Zr compound.

Mitchell, Lee Josey

1999-01-01T23:59:59.000Z

58

Biological availability of nickel arsenides: toxic effects of particulate Ni/sub 5/As/sub 2/  

SciTech Connect

Considerations of (1) oil shale retort operating conditions, (2) oil shale elemental composition, (3) nickel and arsenic physico-chemical properties, and (4) oil shale matrix structure lead to the suggestion that nickel arsenides may be formed during the oil shale retorting process. The biological effects of nickel arsenides have not been previously studied. However, similarities between nickel subarsenide and nickel subsulfide and nickel subselenimide, both of which are known potent carcinogens, have caused concern that nickel arsenides may have adverse effects on biological systems. To determine if fugitive nickel arsenides from an oil shale retort could pose a threat to personnel in the workplace or to other living organisms in the environment, a program to study the toxicity of nickel arsenides has been initiated. Five stable nickel arsenides (Ni/sub 5/As/sub 2/, Ni/sub 2/As, Ni/sub 11/As/sub 8/, NiAs, and NiAs/sub 2/) and nickel arsenic sulfide (NiAsS) are considered possible species for study.

Gurley, L.R.; Tobey, R.A.; Valdez, J.G.; Halleck, M.S.; Barham, S.S.

1981-01-01T23:59:59.000Z

59

GaAs photoconductive semiconductor switch  

DOE Patents (OSTI)

A high gain, optically triggered, photoconductive semiconductor switch (PCSS) implemented in GaAs as a reverse-biased pin structure with a passivation layer above the intrinsic GaAs substrate in the gap between the two electrodes of the device. The reverse-biased configuration in combination with the addition of the passivation layer greatly reduces surface current leakage that has been a problem for prior PCSS devices and enables employment of the much less expensive and more reliable DC charging systems instead of the pulsed charging systems that needed to be used with prior PCSS devices.

Loubriel, Guillermo M. (Sandia Park, NM); Baca, Albert G. (Albuquerque, NM); Zutavern, Fred J. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

60

Ultrafast dynamics of Coulomb correlated excitons in GaAs quantum wells  

Science Conference Proceedings (OSTI)

The author measures the transient nonlinear optical response of room temperature excitons in gallium arsenide quantum wells via multi-wave mixing experiments. The dynamics of the resonantly excited excitons is directly reflected by the ultrafast decay of the induced nonlinear polarization, which radiates the detected multi-wave mixing signal. She characterizes this ultrafast coherent emission in both amplitude and phase, using time- and frequency-domain measurement techniques, to better understand the role of Coulomb correlation in these systems. To interpret the experimental results, the nonlinear optical response of a dense medium is calculated using a model including Coulomb interaction. She contributes three new elements to previous theoretical and experimental studies of these systems. First, surpassing traditional time-integrated measurements, she temporally resolves the amplitude of the ultrafast coherent emission. Second, in addition to measuring the third-order four-wave mixing signal, she also investigates the fifth-order six-wave mixing response. Third, she characterizes the ultrafast phase dynamics of the nonlinear emission using interferometric techniques with an unprecedented resolution of approximately 140 attoseconds. The author finds that effects arising from Coulomb correlation dominate the nonlinear optical response when the density of excitons falls below 3 {times} 10{sup 11} cm{sup {minus}2}, the saturation density. These signatures of Coulomb correlation are investigated for increasing excitation density to gradually screen the interactions and test the validity of the model for dense media. The results are found to be qualitatively consistent with both the predictions of the model and with numerical solutions to the semiconductor Bloch equations. Importantly, the results also indicate current experimental and theoretical limitations, which should be addressed in future research.

Mycek, M.A. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1995-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Transport and strain relaxation in wurtzite InAs-GaAs core-shell heterowires  

Science Conference Proceedings (OSTI)

Indium-arsenide-gallium-arsenide (InAs-GaAs) core-shell, wurtzite nanowires have been grown on GaAs (001) substrates. The core-shell geometries (core radii 11 to 26 nm, shell thickness >2.5 nm) exceeded equilibrium critical values for strain relaxation via dislocations, apparent from transmission electron microscopy. Partial axial relaxation is detected in all nanowires increasing exponentially with size, while radial strain relaxation is >90%, but undetected in nanowires with both smaller core radii electron field-effect mobility compared to bare InAs nanowires.

Kavanagh, Karen L. [Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Salfi, Joe; Savelyev, Igor; Blumin, Marina; Ruda, Harry E. [Centre for Advanced Nanotechnology, University of Toronto, 170 College Street, Toronto, Ontario M5S 3E4 (Canada)

2011-04-11T23:59:59.000Z

62

Behavior of Zircaloy Cladding in the Presence of Gallium  

Science Conference Proceedings (OSTI)

The U.S. Department of Energy has established a dual-track approach to the disposition of plutonium arising from the dismantling of nuclear weapons. Both immobilization and reactor-based mixed-oxide (MOX) fuel technologies are being evaluated. The reactor-based MOX fuel option requires assessment of the potential impact of concentrations of gallium (on the order of 1 to 10 ppm), not present in conventional MOX fuel, on cladding material performance. An experimental program was designed to evaluate the performance of prototypic Zircaloy cladding materials against (1) liquid gallium, and (2) various concentrations of G~03. Three types of tests were performed: (1) corrosion, (2) liquid metal embrittlement, and (3) corrosion-mechanical. These tests were to determine corrosion mechanisms, thresholds for temperature and concentration of gallium that delineate behavioral regimes, and changes in the mechanical properties of Zircaloy. Results have generally been favorable for the use of weapons-grade (WG) MOX fhel. The Zircaloy cladding does react with gallium to form intermetallic compounds at >3000 C; however, this reaction is limited by the mass of gallium and is therefore not expected to be significant with a low level (parts per million) of gallium in the MOX fuel. Furthermore, no evidence for grain boundary penetration by gallium or liquid metal embrittlement was observed.

DiStefano, J.R.; King, J.F.; Manneschmidt, E.T.; Strizak, J.P.; Wilson, D.F.

1998-09-28T23:59:59.000Z

63

Interactions of Zircaloy Cladding with Gallium: Final Report  

Science Conference Proceedings (OSTI)

The U.S. Department of Energy has established a dual-track approach to the disposition of plutonium arising from the dismantling of nuclear weapons. Both immobilization and reactor-based mixed-oxide (MOX) fuel technologies are being evaluated. The reactor-based MOX fuel option requires assessment of the potential impact of concentrations of gallium (on the order of 1 to 10 ppm), not present in conventional MOX fhel, on cladding material performance. Three previous repmts"3 identified several compatibility issues relating to the presence of gallium in MOX fuel and its possible reaction with fiel cladding. Gallium initially present in weapons-grade (WG) plutonium is largely removed during processing to produce MOX fhel. After blending the plutonium with uranium, only 1 to 10 ppm gallium is expected in the sintered MOX fuel. Gallium present as gallium oxide (G~OJ could be evolved as the suboxide (G~O). Migration of the evolved G~O and diffusion of gallium in the MOX matrix along thermal gradients could lead to locally higher concentrations of G~03. Thus, while an extremely low concentration of gallium in MOX fiel almost ensures a lack of significant interaction of gallium whh Zircaloy fhel cladding, there remains a small probability that corrosion effects will not be negligible. General corrosion in the form of surface alloying resulting from formation of intermetallic compounds between Zircaloy and gallium should be ma& limited and, therefore, superficial because of the expected low ratio of gallium to the surface area or volume of the Zircaloy cladding. Although the expected concentration of gallium is low and there is very limited volubility of gallium in zirconium, especially at temperatures below 700 "C,4 grain boundary penetration and liquid metal embrittlement (LME) are forms of localized corrosion that were also considered. One fuel system darnage mechanism, pellet clad interaction, has led to some failure of the Zircaloy cladding in light-water reactors (LWRS). This has been attributed to stresses in the cladding and one or more aggressive fission products. Stress corrosion cracking by iodines' 6 and LME by cadmium7>8 have been reported, and it is known that Zircaloy can be embrittled by some low-melting metals, (e.g., mercury).g LME is a form of environmentally induced embrittlement that can induce cracking or loss of ductility. LME requties wetting and a tensile stress, but it does not require corrosion penetration. Experimentally, it has been demonstrated that gallium can cause embrittlement of some alloys (e.g., aluminum) at low temperatures,'"' ] ] but experiments relative to LME of zirconium by gallium have been limited and inconclusive.*2 This report describes a series of tests designed to establish the effects of low levels of residual gallium in WG-MOX fhel on its compatibility with Zircaloy. In addition, to establish damage mechanisms it was important to understand types of cladding interactions and available stiety margins with respect to gallium concentration.

D.F. Wilson; E.T. Manneschmidt; J.F. King; J.P. Strizak; J.R. DiStefano

1998-09-01T23:59:59.000Z

64

Effect of oxidation on the Mechanical Properties of Liquid Gallium and Eutectic Gallium-Indium  

E-Print Network (OSTI)

Liquid metals exhibit remarkable mechanical properties, in particular large surface tension and low viscosity. However, these properties are greatly affected by oxidation when exposed to air. We measure the viscosity, surface tension, and contact angle of gallium (Ga) and a eutectic gallium-indium alloy (eGaIn) while controlling such oxidation by surrounding the metal with an acid bath of variable concentration. Rheometry measurements reveal a yield stress directly attributable to an oxide skin that obscures the intrinsic behavior of the liquid metals. We demonstrate how the intrinsic viscosity can be obtained with precision through a scaling technique that collapses low- and high-Reynolds number data. Measuring surface tension with a pendant drop method, we show that the oxide skin generates a surface stress that mimics surface tension and develop a simple model to relate this to the yield stress obtained from rheometry. We find that yield stress, surface tension, and contact angle all transition from solid-...

Xu, Qin; Guo, Qiti; Jaeger, Heinrich; Brown, Eric

2012-01-01T23:59:59.000Z

65

It's Elemental - Isotopes of the Element Gallium  

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

Zinc Zinc Previous Element (Zinc) The Periodic Table of Elements Next Element (Germanium) Germanium Isotopes of the Element Gallium [Click for Main Data] Most of the isotope data on this site has been obtained from the National Nuclear Data Center. Please visit their site for more information. Naturally Occurring Isotopes Mass Number Natural Abundance Half-life 69 60.108% STABLE 71 39.892% STABLE Known Isotopes Mass Number Half-life Decay Mode Branching Percentage 56 No Data Available Proton Emission (suspected) No Data Available 57 No Data Available Proton Emission (suspected) No Data Available 58 No Data Available Proton Emission (suspected) No Data Available 59 No Data Available Proton Emission (suspected) No Data Available 60 70 milliseconds Electron Capture 98.40%

66

NIST: X-Ray Mass Attenuation Coefficients - Table 4  

Science Conference Proceedings (OSTI)

... Gafchromic Sensor, Tissue-Equivalent Gas, Methane Based. Gallium Arsenide, Tissue-Equivalent Gas, Propane Based. Glass ...

67

Effect of oxidation on the Mechanical Properties of Liquid Gallium and Eutectic Gallium-Indium  

E-Print Network (OSTI)

Liquid metals exhibit remarkable mechanical properties, in particular large surface tension and low viscosity. However, these properties are greatly affected by oxidation when exposed to air. We measure the viscosity, surface tension, and contact angle of gallium (Ga) and a eutectic gallium-indium alloy (eGaIn) while controlling such oxidation by surrounding the metal with an acid bath of variable concentration. Rheometry measurements reveal a yield stress directly attributable to an oxide skin that obscures the intrinsic behavior of the liquid metals. We demonstrate how the intrinsic viscosity can be obtained with precision through a scaling technique that collapses low- and high-Reynolds number data. Measuring surface tension with a pendant drop method, we show that the oxide skin generates a surface stress that mimics surface tension and develop a simple model to relate this to the yield stress obtained from rheometry. We find that yield stress, surface tension, and contact angle all transition from solid-like to liquid behavior at the same critical acid concentration, thereby quantitatively confirming that the wettability of these liquid metals is due to the oxide skin.

Qin Xu; Nikolai Qudalov; Qiti Guo; Heinrich Jaeger; Eric Brown

2012-01-23T23:59:59.000Z

68

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

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

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

69

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

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

Vacancy-Induced Nanoscale Wire Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Wednesday, 21 December 2005 00:00 Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

70

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

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

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

71

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers  

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

Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Vacancy-Induced Nanoscale Wire Structure in Gallium Selenide Layers Print Low-dimensional materials have gained much attention not only because of the nonstop march toward miniaturization in the electronics industry but also for the exotic properties that are inherent in their small size. One approach for creating low-dimensional structures is to exploit the nanoscale or atomic-scale features that exist naturally in the three-dimensional (bulk) form of materials. By this means, a group from the University of Washington has demonstrated a new way of creating one-dimensional nanoscale structures (nanowires) in the compound gallium selenide. In short, ordered lines of structural vacancies in the material stimulate the growth of "one-dimensional" structures less than 1 nanometer in width.

72

Atomic hydrogen cleaning of polarized GaAs photocathodes  

DOE Green Energy (OSTI)

Atomic hydrogen cleaning followed by heat cleaning at 450 C was used to prepare negative-electron-affinity GaAs photocathodes. When hydrogen ions were eliminated, quantum efficiencies of 15% were obtained for bulk GaAs cathodes, higher than the results obtained using conventional 600 C heat cleaning. The low-temperature cleaning technique was successfully applied to thin, strained GaAs cathodes used for producing highly polarized electrons. No depolarization was observed even when the optimum cleaning time of about 30 seconds was extended by a factor of 100.

Maruyama, Takashi

2003-04-03T23:59:59.000Z

73

Preparation of GaAs photocathodes at low temperature  

SciTech Connect

The preparation of an atomically clean surface is a necessary step in the formation of negative electron affinity (NEA) GaAs. Traditional methods to this end include cleaving, heat cleaning and epitaxial growth. Cleaving has the advantage of yielding a fresh surface after each cleave, but is limited to small areas and is not suitable for specialized structures. Heat cleaning is both simple and highly successful, so it is used as a preparation method in virtually all laboratories employing a NEA source on a regular basis. Due to its high cost and complexity, epitaxial growth of GaAs with subsequent in vacuo transfer is not a practical solution for most end users of GaAs as a NEA electron source. While simple, the heating cleaning process has a number of disadvantages. Here, a variety of cleaning techniques related to preparation of an atomically clean GaAs surface without heating to 600 C are discussed and evaluated.

Mulhollan, G.; Clendenin, J.; Tang, H.

1996-10-01T23:59:59.000Z

74

GaAs Films Prepared by RF-Magnetron Sputtering  

DOE Green Energy (OSTI)

The authors reported on the optical absorption, adhesion, and microstructure of RF-magnetron sputtered films of hydrogenated amorphous and microcrystalline GaAs films for the 1 to 25 {micro}m infrared wavelength rate. Sputtering parameters which were varied include sputtering power, temperature and pressure, and hydrogen sputtering-gas concentration. TEM results show a sharp transition from purely amorphous GaAs to a mixture of microcrystalline GaAs in an amorphous matrix at 34 {+-} 2 C. By optimizing the sputtering parameters, the optical absorption coefficient can be decreased below 100 cm{sup -1} for wavelengths greater than about 1.25 {micro}m. These results represent the lowest reported values of optical absorption for sputtered films of GaAs directly measured by spectrophotometry for the near-infrared wavelength region.

L.H. Ouyang; D.L. Rode; T. Zulkifli; B. Abraham-Shrauner; N. Lewis; M.R. Freeman

2001-08-01T23:59:59.000Z

75

In-Plane Electronic Anisotropy of Underdoped ___122___ Fe-Arsenide Superconductors Revealed by Measurements of Detwinned Single Crystals  

SciTech Connect

The parent phases of the Fe-arsenide superconductors harbor an antiferromagnetic ground state. Significantly, the Neel transition is either preceded or accompanied by a structural transition that breaks the four fold symmetry of the high-temperature lattice. Borrowing language from the field of soft condensed matter physics, this broken discrete rotational symmetry is widely referred to as an Ising nematic phase transition. Understanding the origin of this effect is a key component of a complete theoretical description of the occurrence of superconductivity in this family of compounds, motivating both theoretical and experimental investigation of the nematic transition and the associated in-plane anisotropy. Here we review recent experimental progress in determining the intrinsic in-plane electronic anisotropy as revealed by resistivity, reflectivity and ARPES measurements of detwinned single crystals of underdoped Fe arsenide superconductors in the '122' family of compounds.

Fisher, Ian Randal

2012-05-08T23:59:59.000Z

76

Elimination of charge-enhancement effects in GaAs FETs with a low-temperature grown GaAs buffer layer  

Science Conference Proceedings (OSTI)

The use of low temperature grown GaAs (LT GaAs) buffer layer in GaAs FETs is shown via computer simulation and experimental measurement to reduce ion-induced charge collection by two to three orders of magnitude. This reduction in collected charge is associated with the efficient reduction of charge-enhancement mechanisms in the FETs. Error rate calculations indicate that the soft error rate of LT GaAs integrated circuits will be reduced by several orders of magnitude when compared to conventional FET-based GaAs ICs.

McMorrow, D.; Weatherford, T.R.; Curtice, W.R.; Knudson, A.R.; Buchner, S.; Melinger, J.S.; Tran, L.H.; Campbell, A.B. [Naval Research Lab., Washington, DC (United States)

1995-12-01T23:59:59.000Z

77

Preparation Of Copper Indium Gallium Diselenide Films For Solar Cells  

DOE Patents (OSTI)

High quality thin films of copper-indium-gallium-diselenide useful in the production of solar cells are prepared by electrodepositing at least one of the constituent metals onto a glass/Mo substrate, followed by physical vapor deposition of copper and selenium or indium and selenium to adjust the final stoichiometry of the thin film to approximately Cu(In,Ga)Se.sub.2. Using an AC voltage of 1-100 KHz in combination with a DC voltage for electrodeposition improves the morphology and growth rate of the deposited thin film. An electrodeposition solution comprising at least in part an organic solvent may be used in conjunction with an increased cathodic potential to increase the gallium content of the electrodeposited thin film.

Bhattacharya, Raghu N. (Littleton, CO); Contreras, Miguel A. (Golden, CO); Keane, James (Lakewood, CO); Tennant, Andrew L. (Denver, CO), Tuttle, John R. (Denver, CO); Ramanathan, Kannan (Lakewood, CO); Noufi, Rommel (Golden, CO)

1998-08-08T23:59:59.000Z

78

Appraisal of lupus nephritis by renal imaging with gallium-67  

Science Conference Proceedings (OSTI)

To assess the activity of lupus nephritis, 43 patients with systemic lupus erythematosus (SLE) were studied by gallium imaging. Delayed renal visualization 48 hours after the gallium injection, a positive result, was noted in 25 of 48 scans. Active renal disease was defined by the presence of hematuria, pyuria (10 or more red blood cells or white blood cells per high-power field), proteinuria (1 g or more per 24 hours), a rising serum creatinine level, or a recent biopsy specimen showing proliferative and/or necrotizing lesions involving more than 20 percent of glomeruli. Renal disease was active in 18 instances, inactive in 23, and undetermined in seven (a total of 48 scans). Sixteen of the 18 scans (89 percent) in patients with active renal disease showed positive findings, as compared with only four of 23 scans (17 percent) in patients with inactive renal disease (p less than 0.001). Patients with positive scanning results had a higher rate of hypertension (p = 0.02), nephrotic proteinuria (p = 0.01), and progressive renal failure (p = 0.02). Mild mesangial nephritis (World Health Organization classes I and II) was noted only in the patients with negative scanning results (p = 0.02) who, however, showed a higher incidence of severe extrarenal SLE (p = 0.04). It is concluded that gallium imaging is a useful tool in evaluating the activity of lupus nephritis.

Bakir, A.A.; Lopez-Majano, V.; Hryhorczuk, D.O.; Rhee, H.L.; Dunea, G.

1985-08-01T23:59:59.000Z

79

Boron arsenide thin film solar cell development. Quarterly report No. 1  

DOE Green Energy (OSTI)

A large portion of the effort expended in the first quarter was devoted to the design, assembly, and testing of the film growth apparatus. The reactor has been completed and tested by depositing boron from diborane gas onto heated quartz substrates. The objective of this effort was to achieve film growth, which has been accomplished. Within the last month, attempts to grow boron arsenide films have been made by introducing both diborane and arsine into the reactor. Thin films have been grown on quartz and sapphire (alumina) substrates. Variations in film thickness, composition, degree of crystallinity, and conductivity have been observed as a result of variation of the deposition parameters, such as type and flow rate of carrier gases, substrate temperature, and substrate materials. X-ray analysis of several samples indicates that films containing boron and arsenic have been grown. No crystalline films have been produced to date. Electrical and optical measurements indicate some correlation between at least one of the films grown and the results achieved by Chu, et al. on BAs. Thus far, the electrical conductivity, film topography, optical absorption, index of refraction, impurity type, and photo-conductivity have been investigated on one sample. This material appears to be B/sub x/As/sub y/ and could be BAs. Further investigations will be required to be conclusive.

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

1979-07-01T23:59:59.000Z

80

Epitaxial EuO thin films on GaAs  

SciTech Connect

We demonstrate the epitaxial growth of EuO on GaAs by reactive molecular beam epitaxy. Thin films are grown in an adsorption-controlled regime with the aid of an MgO diffusion barrier. Despite the large lattice mismatch, it is shown that EuO grows well on MgO(001) with excellent magnetic properties. Epitaxy on GaAs is cube-on-cube and longitudinal magneto-optic Kerr effect measurements demonstrate a large Kerr rotation of 0.57 deg., a significant remanent magnetization, and a Curie temperature of 69 K.

Swartz, A. G.; Ciraldo, J.; Wong, J. J. I.; Li Yan; Han Wei; Lin Tao; Shi, J.; Kawakami, R. K. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Mack, S.; Awschalom, D. D. [Center for Spintronics and Quantum Computation, University of California, Santa Barbara, California 93106 (United States)

2010-09-13T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" from the National Library of EnergyBeta (NLEBeta).
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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

Characteristics of graphene FET directly transformed from a resist pattern through interfacial graphitization of liquid gallium  

Science Conference Proceedings (OSTI)

We found that an extremely thin resist pattern on silicon dioxide can be directly transformed into a graphene field effect transistor (FET) channel via interfacial graphitization of liquid gallium. These patterned graphene FETs have p-type characteristics ... Keywords: Conductance, FET, Gallium, Graphene, Graphitization, Resist, Solid phase reaction

Jun-ichi Fujita; Ryuichi Ueki; Takuya Nishijima; Yosuke Miyazawa

2011-08-01T23:59:59.000Z

82

Formation mechanisms of spatially-directed zincblende gallium nitride nanocrystals  

Science Conference Proceedings (OSTI)

We report on the spatially selective formation of GaN nanocrystals embedded in GaAs. Broad-area N{sup +} implantation followed by rapid thermal annealing leads to the formation of nanocrystals at the depth of maximum ion damage. With additional irradiation using a Ga{sup +} focused ion beam, selective lateral positioning of the nanocrystals within the GaAs matrix is observed in isolated regions of increased vacancy concentration. Following rapid thermal annealing, the formation of zincblende GaN is observed in the regions of highest vacancy concentration. The nucleation of zincblende nanocrystals over the wurtzite phase of bulk GaN is consistent with the predictions of a thermodynamic model for the nanoscale size-dependence of GaN nucleation.

Wood, A. W. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Collino, R. R. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Cardozo, B. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Naab, F. [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Wang, Y. Q. [Materials Science and Technology Division, Los Alamos National Lab, Los Alamos, New Mexico 87545 (United States); Goldman, R. S. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-12-15T23:59:59.000Z

83

Measurement of achievable plutonium decontamination from gallium by means of PUREX solvent extraction  

SciTech Connect

The objective of the work described herein was to measure, experimentally, the achievable decontamination of plutonium from gallium by means of the PUREX solvent extraction process. Gallium is present in surplus weapons-grade plutonium (WG-Pu) at a concentration of approximately 1 wt%. Plans are to dispose of surplus WG-Pu by converting it to UO{sub 2}-PuO{sub 2} mixed oxide (MOX) fuel and irradiating it in commercial power reactors. However, the presence of high concentrations of gallium in plutonium is a potential corrosion problem during the process of MOX fuel irradiation. The batch experiments performed in this study were designed to measure the capability of the PUREX solvent extraction process to separate gallium from plutonium under idealized conditions. Radioactive tracing of the gallium with {sup 72}Ga enabled the accurate measurement of low concentrations of extractable gallium. The experiments approximated the proposed flowsheet for WG-Pu purification, except that only one stage was used for each process: extraction, scrubbing, and stripping. With realistic multistage countercurrent systems, much more efficient separations are generally obtained. The gallium decontamination factor (DF) obtained after one extraction stage was about 3 x 10{sup 6}. After one scrub stage, all gallium measurements were less than the detection limit, which corresponded to DFs >5 x 10{sup 6}. All these values exceed a 10{sup 6} DF needed to meet a hypothetical 10-ppb gallium impurity limit in MOX fuel. The results of this study showed no inherent or fundamental problem with regard to removing gallium from plutonium.

Collins, E.D.; Campbell, D.O.; Felker, L.K.

2000-01-01T23:59:59.000Z

84

InGaAsN/GaAs heterojunction for multi-junction solar cells  

DOE Patents (OSTI)

An InGaAsN/GaAs semiconductor p-n heterojunction is disclosed for use in forming a 0.95-1.2 eV bandgap photodetector with application for use in high-efficiency multi-junction solar cells. The InGaAsN/GaAs p-n heterojunction is formed by epitaxially growing on a gallium arsenide (GaAs) or germanium (Ge) substrate an n-type indium gallium arsenide nitride (InGaAsN) layer having a semiconductor alloy composition In.sub.x Ga.sub.1-x As.sub.1-y N.sub.y with 0GaAs layer, with the InGaAsN and GaAs layers being lattice-matched to the substrate. The InGaAsN/GaAs p-n heterojunction can be epitaxially grown by either molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition (MOCVD). The InGaAsN/GaAs p-n heterojunction provides a high open-circuit voltage of up to 0.62 volts and an internal quantum efficiency of >70%.

Kurtz, Steven R. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM); Klem, John F. (Albuquerque, NM); Jones, Eric D. (Edgewood, NM)

2001-01-01T23:59:59.000Z

85

Argonne CNM Highlight: Superhydrophobicity on Silver Nanoplates  

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

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

86

Gallium phosphide high-temperature bipolar junction transistor  

DOE Green Energy (OSTI)

Preliminary results are reported on the development of a high-temperature (> 350/sup 0/C) gallium phosphide bipolar junction transistor (BJT) for goethermal and other energy applications. This four-layer p/sup +/n/sup -/pp/sup +/ structure was fromed by liquid phase epitaxy using a supercooling technique to insure uniform nucleation of the thin layers. Magnesium was used as the p-type dopant to avoid excessive out-diffusion into the lightly doped base. By appropriate choice of electrodes, the device may also be driven as an n-channel junction field-effect transistor. The gallium phosphide BJT is observed to have a common-emitter current gain peaking in the range of 6 to 10 (for temperatures from 20/sup 0/C to 400/sup 0/C) and a room-temperature, punchthrough-limited, collector-emitter breakdown voltage of approximately -6V. Other parameters of interest include an f/sub/ = 400 KHz (at 20/sup 0/C) and a collector base leakage current = 200 ..mu..A (at 350/sup 0/C).

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

1981-03-01T23:59:59.000Z

87

Microsoft PowerPoint - Gallium Oxide_Ramana  

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

Gallium Oxide Nanostructures Gallium Oxide Nanostructures for High Temperature Sensors C.V. Ramana (PI) Evgeny Shafirovich (Co-PI) Mechanical Engineering, University of Texas at El Paso Students: Ernesto Rubio (PhD); S.K. Samala (MS) A.K. Narayana Swamy (PhD); K. Abhilash (MS) Program Manager: Richard Dunst, NETL, DOE Project: DE-FE0007225 Project Period: 10/01/2011 to 09/31/2014 1 06/12/2013 DOE UCR/HBCU Conference, June 11-13, 2013 2 ï‚· Introduction ï‚· Research Objectives ï‚· Experiments â–º Synthesis â–º Characterization ï‚· Results and Discussion â–º Pure Ga 2 O 3 Thin Films â–º W-doped Ga 2 O 3 Thin Films (Physical Methods) ï‚· Summary & Future Work 06/12/2013 DOE UCR/HBCU Conference, June 11-13, 2013 3 06/12/2013 DOE UCR/HBCU Conference, June 11-13, 2013 4 Energy Systems High-T High-T High-P High-P

88

A GaAs transceiver chip for optical data transmission  

SciTech Connect

The present article describes a transceiver VLSI chip for optical data transmission, at 1 Gbit/s (1.4 Gbit/s in selected production), made in GaAs technology. The transceiver makes the parallel-to-serial and serial-to-parallel conversion as well as the encoding and decoding of 32 bit data words. The circuit operates in a completely asynchronous mode, allowing the possibility of switching on-off the transmission in few nsec and of using the transceiver not only in point-to-point topologies, but also in flooding topologies (i.e. star connections). The radiation hardness and the relatively low power consumption, respect to TTL, of the GaAs, extend the use of the chip to a large number of applications in present and future high energy physics experimental apparatus.

Mirabelli, G.; Petrolo, E.; Valente, E. (Ist. Nazionale di Fisica Nucleare, Roma (Italy)); Cardarelli, R.; Santonico, R. (Sezione di Roma 2 and Univ. di Roma (Italy). Ist. Nazionale di Fisica Nucleare); Ferrer, M.L. (Lab. Nazionali di Frascati (Italy). Ist. Nazionale di Fisica Nucleare)

1993-08-01T23:59:59.000Z

89

SEU design consideration for MESFETs on LT GaAs  

SciTech Connect

Computer simulation results are reported on transistor design and single-event charge collection modeling of metal-semiconductor field effect transistors (MESFETs) fabricated in the Vitesse H-GaAsIII{reg_sign} process on Low Temperature grown (LT) GaAs epitaxial layers. Tradeoffs in Single Event Upset (SEU) immunity and transistor design are discussed. Effects due to active loads and diffusion barriers are examined.

Weatherford, T.R.; Radice, R.; Eskins, D. [Naval Postgraduate School, Monterey, CA (United States)] [and others

1997-12-01T23:59:59.000Z

90

Limits on nu_e and anti-nu_e disappearance from Gallium and reactor experiments  

E-Print Network (OSTI)

The deficit observed in the Gallium radioactive source experiments is interpreted as a possible indication of the disappearance of electron neutrinos. In the effective framework of two-neutrino mixing we obtain $\\sin^{2}2\\vartheta \\gtrsim 0.03$ and $\\Delta{m}^{2} \\gtrsim 0.1 \\text{eV}^{2}$. The compatibility of this result with the data of the Bugey and Chooz reactor short-baseline antineutrino disappearance experiments is studied. It is found that the Bugey data present a hint of neutrino oscillations with $0.02 \\lesssim \\sin^{2}2\\vartheta \\lesssim 0.08$ and $\\Delta{m}^{2} \\approx 1.8 \\text{eV}^{2}$, which is compatible with the Gallium allowed region of the mixing parameters. This hint persists in the combined analyses of Bugey and Chooz data, of Gallium and Bugey data, and of Gallium, Bugey, and Chooz data.

Mario A. Acero; Carlo Giunti; Marco Laveder

2007-11-27T23:59:59.000Z

91

Size and shape dependence on melting temperature of gallium nitride nanoparticles  

Science Conference Proceedings (OSTI)

The study of variation of the size and shape effect on the melting property of gallium nitride nanoparticles with their spherical and cylindrical geometrical feature is theoretically explored. A numerical thermodynamical model has been devoted for the ...

Paneerselvam Antoniammal; Dakshanamoorthy Arivuoli

2012-01-01T23:59:59.000Z

92

Polycrystalline Thin-Film Research: Copper Indium Gallium Diselenide (Fact Sheet)  

DOE Green Energy (OSTI)

Capabilities fact sheet for the National Center for Photovoltaics: Polycrystalline Thin-Film Research: Copper Indium Gallium Diselenide that includes scope, core competencies and capabilities, and contact/web information.

Not Available

2011-06-01T23:59:59.000Z

93

The radiation bio-effects of gallum-72 on leukemic cells via a gallium-transferrin complex  

E-Print Network (OSTI)

Improved methods for treatment of leukemia would be advantageous for patients and the medical community. This thesis reports results of a study of the cytotoxicity of radiolabeled transferrin in cultured leukemic cells. K-562 cells, from an erythroleukemic cell line, were grown and growth curves were plotted for characterization. K-562 cells grew logarithmically from approximately 250,000 cells mL?¹ to 700,000 cells mL?¹ and display a doubling time of approximately 20-21 hours. K-562 cells were exposed to x rays at an absorbed dose of 0, 1, 2, and 4 gray. Growth curves were plotted to create a dose response curve. Percent-cell survival in this experiment, and all subsequent experiments, was determined based on the extrapolation of the growth curves to time zero, as compared to a control. An absorbed dose of 1, 2, and 4 gray corresponded to a survival of 77([]14)%, 45([]7.4)% and 20([]2.4)%, respectively. This cell line is relatively resistant to radiation. K-562 cells were exposed to a radioactive gallium-72/stable gallium nitrate mixture to determine the effect gallium-72 decay has on cell survival . Simultaneously, K-562 cells were exposed to a concentration of stable gallium nitrate equivalent to the total gallium concentration, radioactive and stable, of the gallium-72/stable gallium mixture. This allowed a comparison of radioactive and chemotoxic effects due to gallium-72 and stable gallium, respectively. Exposures to gallium-72, at an activity of 184.0 kBq mL?¹, and stable gallium nitrate, at a concentration of 116.7 []M, resulted in a cell survival of 61([]10.5)% and 75([]12. 1)%, respectively. The difference is small when error is taken into consideration. Therefore radioactivity had little effect on cell survival at a specific activity of 6.3 MBq mg?¹. To properly assess the cytotoxicity of gallium-72 the specific activity must be increased. To determine the effect of ape-transferrin on the cytotoxicity of gallium nitrate, K-562 cells were exposed to stable gallium nitrate and increasing amounts of apo-transferrin. Cells exposed to 115.0 []M gallium nitrate exhibited an 82([]8.8)% cell survival compared to 54([]6.9)% following exposure to 115.0 []M gallium nitrate and 3.75 []M apo-transferrin. Apo-transferrin presumably increases cellular uptake of gallium nitrate thereby increasing its cyctotoxic effects.

Forbes, Christen Douglas

1999-01-01T23:59:59.000Z

94

Study of liquid gallium at high pressure using synchrotron x-ray  

SciTech Connect

Liquid gallium has been studied at high pressure up to 2 GPa and ambient temperature in a diamond anvil cell using high energy synchrotron x-ray beam. The total x-ray scattering data of liquid gallium were collected up to Q = 12 A{sup -1} and analyzed using pair distribution functions (PDF). The results indicate that the first nearest neighbor peak and second nearest neighbor (shoulder) peak of PDF in liquid gallium does not change with pressure, whereas the higher order (i.e., third and fourth) nearest neighbor peaks shift towards shorter distance with increasing pressure. Reverse Monte Carlo modeling based on the observed data shows that the coordination number in the liquid gallium increases with pressure from 10.5 at 0.3 GPa to 11.6 at 2 GPa. An atomic arrangement similar to the crystalline phase of Ga(II) with coordination number of 12 is proposed for the locally dense-packed rigid unit in liquid gallium. The volume compression data derived from the structure modeling yield a bulk modulus of 12.1(6) GPa for liquid gallium.

Yu, Tony; Guo Quanzhong; Parise, John [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); Chen Jiuhua [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); Department of Mechanical and Materials Engineering, Center for the Study of Matters at Extreme Conditions, Florida International University, Miami, Florida 33199 (United States); Ehm, Lars [Department of Geosciences, Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794-2100 (United States); National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Huang Shu [Department of Mechanical and Materials Engineering, Center for the Study of Matters at Extreme Conditions, Florida International University, Miami, Florida 33199 (United States); Luo Shengnian [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-06-01T23:59:59.000Z

95

High-Temperature Decomposition of Brønsted Acid Sites in Gallium-Substituted Zeolites  

SciTech Connect

The dehydroxylation of Broensted acid sites (BAS) in Ga-substituted zeolites was investigated at temperatures up to 850 C using X-ray absorption spectroscopy (XAS), Fourier transform infrared spectroscopy (FTIR), and mass spectrometry-temperature programmed desorption (MS-TPD). X-ray absorption near-edge spectroscopy (XANES) revealed that the majority of gallium has tetrahedral coordination even after complete dehydroxylation. The interatomic gallium-oxygen distance and gallium coordination number determined by extended X-ray absorption fine structure (EXAFS) are consistent with gallium in tetrahedral coordination at low T (< 550 C). Upon heating Ga-Beta and Ga-ZSM5 to 850 C, analysis of the EXAFS showed that 70 and 80% of the gallium was still in tetrahedral coordination. The remainder of the gallium was found to be in octahedral coordination. No trigonal Ga atoms were observed. FTIR measurements carried out at similar temperatures show that the intensity of the OH vibration due to BAS has been eliminated. MS-TPD revealed that hydrogen in addition to water evolved from the samples during dehydroxylation. This shows that dehydrogenation in addition to dehydration is a mechanism that contributes to BAS decomposition. Dehydrogenation was further confirmed by exposing the sample to hydrogen to regenerate some of the BAS as monitored by FTIR and MS-TPD.

K Al-majnouni; N Hould; W Lonergan; D Vlachos; R Lobo

2011-12-31T23:59:59.000Z

96

About the 12th International Conference on Metal Organic Vapor ...  

Science Conference Proceedings (OSTI)

... phosphide based materials; Gallium arsenide based materials; High brightness LEDs and solid state lighting; Growth of device structures: LEDs, laser diodes, ...

97

The role of screening of the electron-phonon interaction in relaxation of photoexcited electron-hole plasma in semiconductors  

Science Conference Proceedings (OSTI)

The role of screening of the interaction of the electron-hole plasma with optical phonons is analytically evaluated by the example of gallium arsenide.

Kumekov, S. E. [Kazakh National Technical University (Kazakhstan)], E-mail: skumekov@mail.ru

2008-08-15T23:59:59.000Z

98

Direct measurement of interfacial structure in epitaxial Gd2O3 on GaAs (001) using scanning tunneling microscopy  

Science Conference Proceedings (OSTI)

The epitaxial growth of Gd"2O"3 on GaAs (001) has given a low interfacial density of states, resulting in the demonstration of the first inversion-channel GaAs metal-oxide-semiconductor field-effect transistor. Motivated by the significance of this discovery, ... Keywords: Electronic information, GaAs, Gd2O3, Interfacial stacking, Scanning tunneling microscopy

Y. P. Chiu; M. C. Shih; B. C. Huang; J. Y. Shen; M. L. Huang; W. C. Lee; P. Chang; T. H. Chiang; M. Hong; J. Kwo

2011-07-01T23:59:59.000Z

99

(Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon  

DOE Patents (OSTI)

The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

2001-01-01T23:59:59.000Z

100

(Polyfluoroaryl) fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon  

DOE Patents (OSTI)

The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interfere in the ethylene polymerization process, while affecting the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

NREL preprints for the 23rd IEEE Photovoltaic Specialists Conference  

DOE Green Energy (OSTI)

Topics covered include various aspects of solar cell fabrication and performance. Aluminium-gallium arsenides, cadmium telluride, amorphous silicon, and copper-indium-gallium selenides are all characterized in their applicability in solar cells.

Fitzgerald, M. [ed.

1993-05-01T23:59:59.000Z

102

Electron backscatter diffraction of plutonium-gallium alloys  

Science Conference Proceedings (OSTI)

At Los Alamos National Laboratory a recent experimental technique has been developed to characterize reactive metals, including plutonium arid cerium, using electron backscatter diffraction (EBSD). Microstructural characterization of plutonium and its alloys by EBSD had been previously elusive primarily because of the extreme toxicity and rapid surface oxidation rate associated with plutonium metal. The experimental techniques, which included ion-sputtering the metal surface using a scanning auger microprobe (SAM) followed by vacuum transfer of the sample from the SAM to the scanning electron microscope (SEM), used to obtain electron backscatter diffraction Kikuchi patterns (EBSPs) and orientation maps for plutonium-gallium alloys are described and the initial microstructural observations based on the analysis are discussed. Combining the SEM and EBSD observations, the phase transformation behavior between the {delta} and {var_epsilon} structures was explained. This demonstrated sample preparation and characterization technique is expected to be a powerful means to further understand phase transformation behavior, orientation relationships, and texlure in the complicated plutonium alloy systems.

Boehlert, C. J. (Carl J.); Zocco, T. G. (Thomas G.); Schulze, R. K. (Roland K.); Mitchell, J. N. (Jeremy N.); Pereyra, R. A. (Ramiro A.)

2002-01-01T23:59:59.000Z

103

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

104

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

105

Effect of magnetic field on the mechanical properties of magnetostrictive iron-gallium nanowires  

SciTech Connect

This study experimentally investigates the elastic properties of individual iron-gallium nanowires with and without an applied magnetic bias field. The experiments were conducted with a custom manipulator stage designed for use within a scanning electron microscope, where nanowires were mechanically tested both statically and dynamically. Experiments were also performed in the presence of a 20 Oe dc magnetic field in order to identify any variation in wire properties. The results suggest that iron-gallium nanowires possess an elastic modulus very similar to the macroscale value, tensile strengths of more than double the bulk material, and minor magnetic field induced stiffening at low stresses.

Downey, Patrick R.; Flatau, Alison B. [Department of Aerospace Engineering, University of Maryland, 3181 Martin Hall, College Park, Maryland 20742 (United States); McGary, Patrick D.; Stadler, Bethanie J. H. [Department of Electrical and Computer Engineering, University of Minnesota, 200 Union St., Minneapolis, Minnesota 55455 (United States)

2008-04-01T23:59:59.000Z

106

Universal Heat Conduction in the Iron Arsenide Superconductor KFe2As2: Evidence of a d-Wave State  

SciTech Connect

The thermal conductivity ? of the iron arsenide superconductor KFe2As2 was measured down to 50 mK for a heat current parallel and perpendicular to the tetragonal c axis. A residual linear term at T?0, ?0/T is observed for both current directions, confirming the presence of nodes in the superconducting gap. Our value of ?0/T in the plane is equal to that reported by Dong et al. [ Phys. Rev. Lett. 104 087005 (2010)] for a sample whose residual resistivity ?0 was 10 times larger. This independence of ?0/T on impurity scattering is the signature of universal heat transport, a property of superconducting states with symmetry-imposed line nodes. This argues against an s-wave state with accidental nodes. It favors instead a d-wave state, an assignment consistent with five additional properties: the magnitude of the critical scattering rate ?c for suppressing Tc to zero; the magnitude of ?0/T, and its dependence on current direction and on magnetic field; the temperature dependence of ?(T).

Reid, J.-Ph.; Tanatar, Makariy A.; Juneau-Fecteau, A.; Gordon, R.T.; Rene de Cotret, S.; Doiron-Leyraud, N.; Saito, T.; Fukazawa, H.; Kohori, Y.; Kihou, K.; Lee, C.H.; Iyo, A.; Eisaki, H.; Prozorov, Ruslan; Taillefer, Louis

2012-08-21T23:59:59.000Z

107

Terahertz waveguide spectroscopy of two-dimensional plasmons in GaAs  

E-Print Network (OSTI)

The electrical characteristics of high-mobility, two-dimensional electron gas (2DEG) systems, such as GaAs quantum wells, have been well-studied at low frequencies and in extreme conditions of high magnetic fields and ...

Harris, C. Thomas (Charles Thomas)

2010-01-01T23:59:59.000Z

108

Single-event phenomena in GaAs devices and circuits  

Science Conference Proceedings (OSTI)

The single-event upset (SEU) characteristics of GaAs devices and circuits are reviewed. GaAs FET-based integrated circuits (IC`s) are susceptible to upsets from both cosmic-ray heavy ions and protons trapped in the Earth`s radiation belts. The origin of the SEU sensitivity of GaAs IC`s is discussed in terms of both device-level and circuit-level considerations. At the device level, efficient charge-enhancement mechanisms through which more charge can be collected than is deposited by the ion have a significant negative impact on the SEU characteristics of GaAs IC`s. At the circuit level, different GaAs digital logic topologies exhibit different levels of sensitivity to SEU because of variations in parameters, including logic levels, capacitances, and the degree of gate or peripheral isolation. The operational and SEU characteristics of several different GaAs logic families are discussed. Recent advances in materials and processing that provide possible solutions to the SEU problem are addressed.

McMorrow, D.; Melinger, J.S.; Campbell, A.B. III; Weatherford, T.R. [Naval Research Lab., Washington, DC (United States); Buchner, S.; Knudson, A.R.; Tran, L.H. [SFA Inc., Landover, MD (United States)

1996-04-01T23:59:59.000Z

109

Preconceptual design for separation of plutonium and gallium by ion exchange  

SciTech Connect

The disposition of plutonium from decommissioned nuclear weapons, by incorporation into commercial UO{sub 2}-based nuclear reactor fuel, is a viable means to reduce the potential for theft of excess plutonium. This fuel, which would be a combination of plutonium oxide and uranium oxide, is referred to as a mixed oxide (MOX). Following power generation in commercial reactors with this fuel, the remaining plutonium would become mixed with highly radioactive fission products in a spent fuel assembly. The radioactivity, complex chemical composition, and large size of this spent fuel assembly, would make theft difficult with elaborate chemical processing required for plutonium recovery. In fabricating the MOX fuel, it is important to maintain current commercial fuel purity specifications. While impurities from the weapons plutonium may or may not have a detrimental affect on the fuel fabrication or fuel/cladding performance, certifying the effect as insignificant could be more costly than purification. Two primary concerns have been raised with regard to the gallium impurity: (1) gallium vaporization during fuel sintering may adversely affect the MOX fuel fabrication process, and (2) gallium vaporization during reactor operation may adversely affect the fuel cladding performance. Consequently, processes for the separation of plutonium from gallium are currently being developed and/or designed. In particular, two separation processes are being considered: (1) a developmental, potentially lower cost and lower waste, thermal vaporization process following PuO{sub 2} powder preparation, and (2) an off-the-shelf, potentially higher cost and higher waste, aqueous-based ion exchange (IX) process. While it is planned to use the thermal vaporization process should its development prove successful, IX has been recommended as a backup process. This report presents a preconceptual design with material balances for separation of plutonium from gallium by IX.

DeMuth, S.F.

1997-09-30T23:59:59.000Z

110

Heavy ion SEU immunity of a GaAs complementary HIGFET circuit fabricated on a low temperature grown buffer layer  

SciTech Connect

The authors compare dynamic SEU characteristics of GaAs complementary HIGFET devices fabricated on conventional semi-insulating substrates versus low temperature grown GaAs (LT GaAs) buffer layers. Heavy ion test results on shift register and flip-flop devices from the same process lot demonstrate that the LT GaAs layer provides immunity from upsets, even at an LET value of 90 MeV {center_dot} cm{sup 2}/mg. This result is also consistent with pulsed laser measurements performed on the same flip-flop circuits used in the ion test.

Marshall, P.W.; Weatherford, T.; Carts, M. [Naval Research Lab., Washington, DC (United States)]|[SFA, Inc., Landover, MD (United States); Dale, C.J.; McMorrow, D. [Naval Research Lab., Washington, DC (United States); Peczalski, A.; Baier, S.; Nohava, J.; Skogen, J. [Honeywell Systems and Research Center, Bloomington, MN (United States)

1995-12-01T23:59:59.000Z

111

GaAs ohmic contacts for high temperature devices  

DOE Green Energy (OSTI)

Instrumentation requirements for geothermal wells, jet engines, and nuclear reactors have exceeded the high temperature capability of silicon devices. As one part of a program to develop high temperature compound semiconductor devices, four basic ohmic contact systems for n-type GaAs have been evaluated for contact resistance as a function of temperature (24 to 350/sup 0/C) and time (at 300/sup 0/C): Ni/AuGe; Ag/Si and Ag/Ni/Si; Al/Ge and Al/AlGe; and Au/Nb/Si and Pt/Nb/Si. Optimization of processing parameters produced viable high temperature contacts with all but the Al/Ge systems. Aging at 300/sup 0/C changed the contact resistivity in only the Ag/Ni/Si contacts. Film adhesion was excellent for the Al/Ge, Ni/AuGe, and Ag/Si systems as measured with ultrasonic Al wire bond pull strengths. Lower adhesion was noticed with Nb/Si systems measured with gold wire bond pull strengths.

Coquat, J.A.; Palmer, D.W.

1980-01-01T23:59:59.000Z

112

Quantum wells on indium gallium arsenic compositionally graded buffers realized by molecular beam epitaxy  

E-Print Network (OSTI)

For a long time, there has been a desire to extend the emission wavelength of GaAs-based quantum well lasers, with the aim of eventually replacing InP with GaAs as the substrate of choice for communication applications. ...

Choy, Henry Kwong Hin, 1974-

2005-01-01T23:59:59.000Z

113

Effects of low-temperature buffer-layer thickness and growth temperature on the SEE sensitivity of GaAs HIGFET circuits  

Science Conference Proceedings (OSTI)

Heavy-ion Single Event Effects (SEE) test results reveal the role of growth temperature and buffer layer thickness in the use of a low-temperature grown GaAs (LT GaAs) buffer layer for suppressing SEE sensitivity in GaAs HIGFET circuits.

Weatherford, T.R.; Fouts, D.J. [Naval Postgraduate School, Monterey, CA (United States); Marshall, P.W. [Naval Research Lab., Washington, DC (United States)]|[SFA, Inc., Largo, MD (United States); Marshall, C.J. [Naval Research Lab., Washington, DC (United States); Mathes, B.; LaMacchia, M. [Motorola Government Systems, Scottsdale, AZ (United States)

1997-12-01T23:59:59.000Z

114

The control of size and areal density of InAs self-assembled quantum dots in selective area molecular beam epitaxy on GaAs (001) surface  

Science Conference Proceedings (OSTI)

The growth of InAs quantum dots (QDs) on GaAs (001) substrates by selective area molecular beam epitaxy (SA-MBE) with dielectric mask is investigated. The GaAs polycrystals on the mask, which is formed during growth due to low GaAs selectivity between ... Keywords: InAs quantum dots, Molecular beam epitaxy, Selective area epitaxy

J. C. Lin; P. W. Fry; R. A. Hogg; M. Hopkinson; I. M. Ross; A. G. Cullis; R. S. Kolodka; A. I. Tartakovskii; M. S. Skolnick

2006-12-01T23:59:59.000Z

115

Micro-Photoluminescence Characterization of Low Density Droplet GaAs Quantum Dots for Single Photon Sources  

Science Conference Proceedings (OSTI)

The GaAs quantum dots in AlGaAs barriers were grown by droplet epitaxy, emitting around 700 nm in wavelength which is compatible with low cost Si based detectors. The excitation power dependent and time resolved micro-photoluminescence measurements identified optical characteristics of exciton and biexciton states which are attributed to good quantum confinements in GaAs QDs.

Ha, S.-K.; Song, J. D.; Lim, J. Y.; Choi, W. J.; Han, I. K.; Lee, J. I. [Nano Convergence Devices Center, KIST, Seoul 136-791 (Korea, Republic of); Bounouar, S.; Donatini, F.; Dang, L. S.; Poizat, J. P. [CEA/CNRS/UJF team 'Nanophysics and semiconductors', Institute Neel/CNRS-UJF, 38042 Grenoble (France); Kim, J. S. [Department of Physics, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of)

2011-12-23T23:59:59.000Z

116

Heteroepitaxial growth of InAs on GaAs(001) by in situ STM located inside MBE growth chamber  

Science Conference Proceedings (OSTI)

The growth of InAs on GaAs(001) is of great interest primarily due to the self-assembly of arrays of quantum dots (QDs) with excellent opto-electronic properties. However, a basic understanding of their spontaneous formation is lacking. Advanced experimental ... Keywords: GaAs, InAs, Molecular beam epitaxy, Quantum dots, Scanning tunneling microscopy

S. Tsukamoto; G. R. Bell; Y. Arakawa

2006-12-01T23:59:59.000Z

117

Influence of post deposition annealing on Y2O3-gated GaAs MOS capacitors and their reliability issues  

Science Conference Proceedings (OSTI)

The feasibility of employing yttrium oxide (Y"2O"3) as high-k gate dielectrics for GaAs metal-oxide-semiconductor (MOS) devices has been investigated. MOS capacitors were fabricated using RF-sputtered deposited Y"2O"3 films on NH"4OH treated n-GaAs substrate. ... Keywords: GaAs, TDDB, Trapping centroid, Y2O3

P. S. Das; A. Biswas

2011-03-01T23:59:59.000Z

118

Ternary rare-earth zinc arsenides REZn{sub 1-x}As{sub 2} (RE=La-Nd, Sm)  

SciTech Connect

The ternary rare-earth zinc arsenides REZn{sub 1-x}As{sub 2} (RE=La-Nd, Sm) were prepared by reaction of the elements at 800 deg. C. Single-crystal and powder X-ray diffraction analysis revealed a defect SrZnBi{sub 2}-type average structure for the La member (Pearson symbol tI16, space group I4/mmm, Z=4; a=4.0770(9) A, c=20.533(5) A), in contrast to defect HfCuSi{sub 2}-type average structures for the remaining RE members (Pearson symbol tP8, space group P4/nmm, Z=2; a=4.0298(5)-3.9520(4) A, c=10.222(1)-10.099(1) A in the progression from Ce to Sm). The homogeneity range is not appreciable (estimated to be narrower than 0.6<1-x<0.7 in SmZn{sub 1-x}As{sub 2}) and the formula REZn{sub 0.67}As{sub 2} likely represents the Zn-rich phase boundary. The Ce-Nd members are Curie-Weiss paramagnets. LaZn{sub 0.67}As{sub 2} shows activated behavior in its electrical resistivity, whereas SmZn{sub 0.67}As{sub 2} exhibits anomalies in its temperature dependence of the electrical resistivity. - Graphical abstract: LaZn{sub 1-x}As{sub 2} adopts a SrZnBi{sub 2}-type structure whereas the remaining members of the REZn{sub 1-x}As{sub 2} series (RE=Ce-Nd, Sm) adopt a HfCuSi{sub 2}-type structure. Highlights: > REZn{sub 1-x}As{sub 2} adopts SrZnBi{sub 2}-type (RE=La) or HfCuSi{sub 2}-type (RE=Ce-Nd, Sm) structures. > Trends in RE substitution and local distortion around Zn-centered tetrahedra can be rationalized by geometrical factors. > Zn vacancies occur to reduce Zn-As and As-As antibonding interactions.

Stoyko, Stanislav S. [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada); Mar, Arthur, E-mail: arthur.mar@ualberta.ca [Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2 (Canada)

2011-09-15T23:59:59.000Z

119

Thermodynamic property evaluation and magnetic refrigeration cycle analysis for gadolinium gallium garnet  

SciTech Connect

Based on relevant material property data and previous model formulations, a magnetothermodynamic property map for gadolinium gallium garnet (Gd{sub 3}Ga{sub 5}O{sub 12}) was adapted for refrigeration cycle analysis in the temperature range 4-40 K and the magnetic field range 0-6 T. Employing methods similar to those previously developed for other materials and temperature ranges, assessments of limitations and relative performance were made for Carnot, ideal regenerative, and pseudo-constant field regenerative cycles. It was found that although Carnot cycle limitations on available temperature lift for gadolinium gallium garnet are not as severe as the limitations for materials previously examined, considerable improvement in cooling capacity and temperature lift combinations can be achieved by using regenerative cycles if serious loss mechanisms are avoided.

Murphy, R.W.

1994-12-01T23:59:59.000Z

120

(Polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of enhanced utility, uses thereof, and products based thereon  

DOE Patents (OSTI)

The (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are novel weakly coordinating anions which are are highly fluorinated. (Polyfluoroaryl)fluoroanions of one such type contain at least one ring substituent other than fluorine. These (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium have greater solubility in organic solvents, or have a coordinative ability essentially equal to or less than that of the corresponding (polyfluoroaryl)fluoroanion of aluminum, gallium, or indium in which the substituent is replaced by fluorine. Another type of new (polyfluoroaryl)fluoroanion of aluminum, gallium, and indium have 1-3 perfluorinated fused ring groups and 2-0 perfluorophenyl groups. When used as a cocatalyst in the formation of novel catalytic complexes with d- or f-block metal compounds having at least one leaving group such as a methyl group, these anions, because of their weak coordination to the metal center, do not interefere in the ethylene polymerization process, while affecting the the propylene process favorably, if highly isotactic polypropylene is desired. Thus, the (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium of this invention are useful in various polymerization processes such as are described.

Marks, Tobin J. (Evanston, IL); Chen, You-Xian (Midland, MI)

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Particle-induced mitigation of SEU sensitivity in high data rate GaAs HIGFET technologies  

Science Conference Proceedings (OSTI)

Proton and heavy ion data on two GaAs HIGFET logic families, one source coupled (SCFL) and the other complementary (C-HIGFET), show the importance of dynamic testing and develop a new technique for mitigating SEU sensitivity by minimizing charge enhancement effects.

Marshall, P.W.; Weatherford, T.R. [Naval Research Lab., Washington, DC (United States)]|[SFA, Inc., Landover, MD (United States); Dale, C.J. [Naval Research Lab., Washington, DC (United States); La Macchia, M. [Motorola, Inc., Phoenix, AZ (United States); LaBel, K.A. [National Aeronautics and Space Administration, Greenbelt, MD (United States)

1995-12-01T23:59:59.000Z

122

Pulsed laser-induced charge collection in GaAs MESFETs  

Science Conference Proceedings (OSTI)

Pulsed picosecond lasers with variable wavelength have been used to investigate the details of charge collection in GaAs MESFETs. In short gate-length devices, charge collection at the drain may be much larger than at the gate and greater than the charge produced by the laser pulses.

Knudson, A.R.; Campbell, A.B.; McMorrow (Naval Research Lab., Washington, DC (USA)); Buchner, S.; Kang, K. (Martin Marietta Labs., Baltimore, MD (USA)); Weatherford, T. (SFA Inc., Landover, MD (US)); Srinivas, V.; Swartzlander, G.A. Jr.; Chen, Y.J. (Maryland Univ., Baltimore, MD (USA))

1990-12-01T23:59:59.000Z

123

Time response of the high-field electron distribution function in GaAs  

Science Conference Proceedings (OSTI)

Numerical calculations have been made of the high-field electron distribution function for GaAs, its small-signal frequency response and its behavior in large sinusoidal electric fields-The response speed is limited by the low scattering rate within ...

H. D. Rees

1969-09-01T23:59:59.000Z

124

Entanglement in GaAs and CdSe quantum dots: Exact calculations and DFT approximations  

Science Conference Proceedings (OSTI)

We consider two electrons confined in spherical GaAs and CdSe quantum dots and calculate their ground-state spatial entanglement exactly within a parabolic confinement model. We propose a perturbative scheme to approximate the above entanglement within ... Keywords: Density-functional theory, Entanglement, Quantum dots, Quantum information, Semiconductors

J. P. Coe; A. Sudbery; I. D'Amico

2009-03-01T23:59:59.000Z

125

A search for spin-polarized photoemission from GaAs using light with orbital angular momentum  

Science Conference Proceedings (OSTI)

Laser light with photon energy near the bandgap of GaAs and with different amounts of orbital angular momentum was used to produce photoemission from unstrained GaAs. The degree of electron spin polarization was measured using a micro-Mott polarimeter and found to be consistent with zero with an upper limit of ~3% for light with up to ±5{bar h} of orbital angular momentum. In contrast, the degree of spin polarization was 32.32 ± 1.35% using circularly-polarized laser light at the same wavelength, which is typical of bulk GaAs.

Nathan Clayburn, James McCarter, Joan Dreiling, Bernard Poelker, Dominic Ryan, Timothy Gay

2013-01-01T23:59:59.000Z

126

The Surface Activation Layer of GaAs Negative Electron Affinity Photocathode Activated by Cs, Li and NF3  

Science Conference Proceedings (OSTI)

The lifetime of GaAs photocathodes can be greatly improved by introducing Li in the Cs+NF{sub 3} activation process. The surface activation layer of such photocathodes is studied by synchrotron radiation photoemission and is compared with GaAs photocathodes activated without Li. The charge distributions of N, F and Cs experience significant changes when Li is added in the activation. In addition, the presence of Li causes NF{sub x} molecules to take an orientation with F atoms on top. All these changes induced by Li hold the key for the lifetime improvement of GaAs photocathodes.

Sun, Yun; /SLAC, SSRL; Kirby, R.E.; /Saxet Surface Sci.; Maruyama, T.; /SLAC; Mulhollan, G.A.; Bierman, J.C.; /Saxet Surface Sci.; Pianetta, P.; /SLAC, SSRL

2009-12-11T23:59:59.000Z

127

Surface science analysis of GaAs photocathodes following sustained electron beam delivery  

DOE Green Energy (OSTI)

Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Photocathode quantum efficiency (QE) degradation is due to residual gasses in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector and one unused, were also analyzed using Transmission Electron Microscopy (TEM) and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but shows evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

Carlos Hernandez-Garcia, Fay Hannon, Marcy Stutzman, V. Shutthanandan, Z. Zhu, M. Nandasri, S. V. Kuchibhatla, S. Thevuthasan, W. P. Hess

2012-06-01T23:59:59.000Z

128

Kinetics for the reaction of hydrogen with a plutonium-1 weight percent gallium alloy powder  

Science Conference Proceedings (OSTI)

Kinetics for the reaction of hydrogen with plutonium-1 w/o gallium were measured using powder prepared ''in situ.'' The rates obeyed a first-order rate law and were independent of temperature from -29/degree/ to 355/degree/C. A pressure dependence proportional to P/sup //one-half/ was observed at pressures less than 1 kPa. From 1 to 70 kPa the pressure dependence rapidly decreased. Total pressure dependence could be accurately described by a Langmuir equation. Results indicate an adsorption-controlled reaction at low pressures and a reaction-controlled process at high pressure. 19 refs.

Stakebake, J.L.

1981-11-01T23:59:59.000Z

129

Perturbation potential produced by a monolayer of InAs on GaAs,,100... Z. Barticevic,1  

E-Print Network (OSTI)

, using the linear muffin-tin orbital tight-binding method, for the potential of an InAs 001 monolayerAs sand- wiched in bulk 001 -GaAs. This result evidences the impor- tance of excitonic effects in InAs ML of InAs in bulk GaAs 001 have been done mainly using the sp3 s* tight-binding TB method. In spite of its

Vargas, Patricio

130

Spin-Resolved Electronic Structure of Ultrathin Epitaxial Fe Films on Vicinal and Singular GaAs(100) Substrates  

SciTech Connect

Recently there has been considerable interest in the study of spin injection at ferromagnetic semiconductor heterojunctions and ferromagnetic metal--semiconductor contacts. Studies of ntype semiconductors have demonstrated spin-coherent transport over large distances5 and the persistence of spin coherence over a sizeable time scale. Clearly such investigations have been stimulated by the potential of the development of ''spintronics'', electronic devices utilizing the information of the electron spin states. To understand and improve the magnetic properties of ultrathin Fe films on GaAs has been the aim of many research groups over recent years. The interest in this system has both technological and fundamental scientific motivations. Technologically, Fe on GaAs may serve to realize spin electronic devices. From a fundamental science point of view, Fe on GaAs serves as a prototype for studies of the interplay between the crystalline structure and morphology of an ultrathin film, its electronic structure and the long range magnetic order it exhibits. Furthermore, it is well known that an oxidized Cs layer on GaAs substantially alters the work-function of the GaAs surface, which plays a very important role in the application of GaAs as a spin polarized electron source.

Morton, S A; Waddill, G D; Spangenberg, M; Seddon, E A; Neal, J; Shen, T; Tobin, J G

2003-03-10T23:59:59.000Z

131

Anionic Gallium-Based Metal;#8722;Organic Framework and Its Sorption and Ion-Exchange Properties  

SciTech Connect

A gallium-based metal-organic framework Ga{sub 6}(C{sub 9}H{sub 3}O{sub 6}){sub 8} {center_dot} (C{sub 2}H{sub 8}N){sub 6}(C{sub 3}H{sub 7}NO){sub 3}(H{sub 2}O){sub 26} [1, Ga{sub 6}(1,3,5-BTC){sub 8} {center_dot} 6DMA {center_dot} 3DMF {center_dot} 26H{sub 2}O], GaMOF-1; BTC = benzenetricarboxylate/trimesic acid and DMA = dimethylamine, with space group I{bar 4}3d, a = 19.611(1) {angstrom}, and V = 7953.4(6) {angstrom}{sup 3}, was synthesized using solvothermal techniques and characterized by synchrotron-based X-ray microcrystal diffraction. Compound 1 contains isolated gallium tetrahedra connected by the organic linker (BTC) forming a 3,4-connected anionic porous network. Disordered positively charged ions and solvent molecules are present in the pore, compensating for the negative charge of the framework. These positively charged molecules could be exchanged with alkali-metal ions, as is evident by an ICP-MS study. The H{sub 2} storage capacity of the parent framework is moderate with a H{sub 2} storage capacity of {approx}0.5 wt % at 77 K and 1 atm.

Banerjee, Debasis; Kim, Sun Jin; Wu, Haohan; Xu, Wenqian; Borkowski, Lauren A.; Li, Jing; Parise, John B. (Kwangju); (Rutgers); (SBU)

2012-04-30T23:59:59.000Z

132

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

133

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"

134

Ion Trap in a Semiconductor Chip  

E-Print Network (OSTI)

The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ion. Work on miniaturizing electromagnetic traps to the micrometer scale promises even higher levels of control and reliability. Compared with 'chip traps' for confining neutral atoms, ion traps with similar dimensions and power dissipation offer much higher confinement forces and allow unparalleled control at the single-atom level. Moreover, ion microtraps are of great interest in the development of miniature mass spectrometer arrays, compact atomic clocks, and most notably, large scale quantum information processors. Here we report the operation of a micrometer-scale ion trap, fabricated on a monolithic chip using semiconductor micro-electromechanical systems (MEMS) technology. We confine, laser cool, and measure heating of a single 111Cd+ ion in an integrated radiofrequency trap etched from a doped gallium arsenide (GaAs) heterostructure.

D. Stick; W. K. Hensinger; S. Olmschenk; M. J. Madsen; K. Schwab; C. Monroe

2006-01-09T23:59:59.000Z

135

Single event induced charge transport modeling of GaAs MESFETs  

SciTech Connect

Previous studies examining single event charge collection in GaAs MESFETs have revealed enhanced charge collection, in which the drain charge collection can be as high as 8 times the amount of charge deposited in the device. The understanding of these charge amplifying mechanisms requires correlation between experimental and simulation analysis. Two-dimensional computer simulations of charge collection phenomena in GaAs MESFETs have been performed for alpha and laser ionization. In both cases more charge is collected than is created by the ionizing event. The simulations indicate that a bipolar transport mechanism (t < 60 ps) and a channel modulation mechanism (t > 40 ps) are responsible for this enhanced charge collection.

Weatherford, T.R.; Knudson, A.R. (SFA Inc., Landover, MD (United States)); McMorrow, D.; Campbell, A.B. (Naval Research Lab., Washington, DC (United States)); Curtice, W.R. (W.R. Curtice Consulting, Princeton Junction, NJ (United States))

1993-12-01T23:59:59.000Z

136

Heavy ion and proton analysis of a GaAs C-HIGFET SCRAM  

Science Conference Proceedings (OSTI)

The authors present heavy ion and proton upset measurements, including total dose, and displacement damage on a one micron, GaAs, complementary-heterostructure insulated-gate FET (C-HIGFET) 1k x 1 SRAM. SEU characteristics show a two order of magnitude improvement over GaAs MESFET technology. Heavy-ion upset equilibrium measurements show that all cells upset with equal probability at the five percent LET threshold. This indicates that for this device the shape of the cross section versus LET curve is a result of a probability distribution that applies to all cells and is not the result of variations in cell sensitivities. The data set also indicates that the traditional two-dimensional cos([theta]) normalization to LET and fluence are not applicable to this technology.

Cutchin, J.H.; Marshall, P.W.; Weatherford, T.R. (SFA Inc., Landover, MD (United States) Naval Research Lab., Washington, DC (United States)); Langworthy, J.; Petersen, E.L.; Campbell, A.B. (Naval Research Lab., Washington, DC (United States)); Hanka, S.; Peczalski, A. (Honeywell, Inc., Minneapolis, MN (United States))

1993-12-01T23:59:59.000Z

137

SEU rate prediction and measurement of GaAs SRAMs onboard the CRRES satellite  

SciTech Connect

The Combined Release and Radiation Effects Satellite (CRRES) launched in July of 1990 included experiments to study effects of Single Event Upset (SEU) on various microelectronic ICs. The MicroElectronics Package (MEP) subsection of the satellite experiments monitored upset rates on 65 devices over a 15 month period. One of the purposes of the SEU experiments was to determine if the soft error modeling techniques were of sufficient accuracy to predict error rates, and if not, to determine where the deficiencies existed. An analysis is presented on SPICE predicted, SEU ground tested, and CRRES observed heavy ion and proton soft error rates of GaAs SRAMs. Upset rates overestimated the susceptibility of the GaAs SRAMs. Differences are accounted to several factors.

Weatherford, T.R.; McDonald, P.T. (SFA, Inc., Landover, MD (United States) Naval Research Lab., Washington, DC (United States)); Campbell, A.B.; Langworthy, J.B. (Naval Research Lab., Washington, DC (United States))

1993-12-01T23:59:59.000Z

138

Effects of atomic hydrogen and deuterium exposure on high polarization GaAs photocathodes  

DOE Green Energy (OSTI)

Strained-layer GaAs and strained-superlattice GaAs photocathodes are used at Jefferson Laboratory to create high average current beams of highly spin-polarized electrons. High electron yield, or quantum efficiency (QE), is obtained only when the photocathode surface is atomically clean. For years, exposure to atomic hydrogen or deuterium has been the photocathode cleaning technique employed at Jefferson Laboratory. This work demonstrates that atomic hydrogen cleaning is not necessary when precautions are taken to ensure that clean photocathode material from the vendor is not inadvertently dirtied while samples are prepared for installation inside photoemission guns. Moreover, this work demonstrates that QE and beam polarization can be significantly reduced when clean high-polarization photocathode material is exposed to atomic hydrogen from an rf dissociator-style atomic hydrogen source. Surface analysis provides some insight into the mechanisms that degrade QE and polarization due to atomic hydrogen cleaning.

M. Baylac; P. Adderley; J. Brittian; J. Clark; T. Day; J. Grames; J. Hansknecht; M. Poelker; M. Stutzman; A. T. Wu; A. S. Terekhov

2005-12-01T23:59:59.000Z

139

Triggering GaAs lock-on switches with laser diode arrays  

Science Conference Proceedings (OSTI)

Many of the applications that require the unique capabilities of Photoconductive Semiconductor Switches (PCSS) demand a compact package. We have been able to demonstrate that GaAs switches operated in the high gain mode called lock-on'' meet the required electrical switching parameters of several such applications using small switch sizes. The only light source that has enough power to trigger a PCSS and is compatible with a small package is a laser diode. This paper will describe the progress that leads to the triggering of high power PCSS switches with laser diodes. Our goal is to switch up to 5 kA in a single shot mode and up to 100 MW repetitively at up to 10 kHz. These goals are feasible since the switches can be used in parallel or in series. Low light level triggering became possible after the discovery of a high electric field, high gain switching mode in GaAs (and later in InP). At electric fields below 3 kV/cm GaAs switches are activated by creation of, at most, only one conduction electron- valence hole pair per photon absorbed in the sample. This linear mode demands high laser power and, after the light is extinguished, the carriers live for only a few nanoseconds. At higher electric fields GaAs behaves as a light activated Zener diode. The laser light generates carriers as in the linear mode and the field induces gain such that the amount of light required to trigger the switch is reduced by a factor of up to 500. The gain continues until the field across the sample drops to a material dependent lock-on field. At this point the switch will carry as much current as, and for as long as, the circuit can maintain the lock-on field. The gain in the switch allows for the use of laser diodes. 8 refs., 11 figs.

Loubriel, G.M.; Helgeson, W.D.; McLaughlin, D.L.; O'Malley, M.W.; Zutavern, F.J. (Sandia National Labs., Albuquerque, NM (USA)); Rosen, A.; Stabile, P.J. (David Sarnoff Research Center, Princeton, NJ (USA))

1990-01-01T23:59:59.000Z

140

Proton and heavy ion upsets in GaAs MESFET devices  

Science Conference Proceedings (OSTI)

This paper reports on proton and heavy SEU data that has been obtained for devices made by several GaAs MESFET manufacturers. Proton energy dependence and proton and heavy ion upset cross sections are reported. Measurements of charge collection from latches designed with various gate widths show that charge collection depths appear deeper than the 1 {mu}m depth expected. Critical charge does not scale linearly with area. Proton upset cross sections are reduced with increased device width.

Weatherford, T.R.; Tran, L. (Sachs/Freeman Associates, Inc., Bowie, MD (United States)); Stapor, W.J.; Petersen, E.L.; Langworthy, J.B.; McMorrow, D. (Naval Research Lab., Washington, DC (United States)); Abdel-Kader, W.G.; McNulty, P.J. (Clemson Univ., SC (United States). Dept. of Physics and Astronomy)

1991-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" from the National Library of EnergyBeta (NLEBeta).
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141

DIRECT DETERMINATION OF THE STACKING ORDER IN GD2O3 EPI LAYERS ON GAAS.  

SciTech Connect

We have used Coherent Bragg Rod Analysis (COBRA) to investigate the atomic structure of a 5.6 nm thick Gd{sub 2}O{sub 3} film epitaxially grown on a (100) GaAs substrate. COBRA is a method to directly obtain the structure of systems periodic in two-dimensions by determining the complex scattering factors along the substrate Bragg rods. The system electron density and atomic structure are obtained by Fourier transforming the complex scattering factors into real space. The results show that the stacking order of the first seven Gd{sub 2}O{sub 3} film layers resembles the stacking order of Ga and As layers in GaAs then changes to the stacking order of cubic bulk Gd{sub 2}O{sub 3}. This behavior is distinctly different from the measured stacking order in a 2.7 nm thick Gd{sub 2}O{sub 3} in which the GaAs stacking order persists throughout the entire film.

YACOBY,Y.; SOWWAN,M.; PINDAK,R.; CROSS,J.; WALKO,D.; STERN,E.; PITNEY,J.; MACHARRIE,R.; HONG,M.; CLARKE,R.

2002-12-06T23:59:59.000Z

142

Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide  

Science Conference Proceedings (OSTI)

In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide ({alpha}-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and R{sub s} measurement systems and HSC chemistry simulation tool. According to the experimental and simulated results, the diffused Ti atoms were easily oxidized due to its lowest oxidation free energy. Since oxygen atoms were decomposed from the {alpha}-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in {alpha}-IGZO was dramatically increased, contributing to the decrease of resistivity ({rho}) from 1.96 {Omega} cm (as-deposited {alpha}-IGZO) to 1.33 Multiplication-Sign 10{sup -3}{Omega} cm (350 Degree-Sign C annealed {alpha}-IGZO).

Choi, Seung-Ha [School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Development Group of Oxide Semiconductor, Samsung Display, Yongin 446-711 (Korea, Republic of); Jung, Woo-Shik [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Park, Jin-Hong [School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2012-11-19T23:59:59.000Z

143

Atomistic model of helium bubbles in gallium-stabilized plutonium alloys  

Science Conference Proceedings (OSTI)

The varying thermodynamic stability of gallium- (Ga-) stabilized plutonium (Pu) alloys with temperature affords a unique setting for the development of self-irradiation damage. Here, fundamental characteristics of helium (He) bubbles in these alloys with respect to temperature, gallium concentration, and He-to-vacancy ratio are modeled at the atomistic level with a modified embedded atom potential that takes account of this varying stability. Aside from the bubbles themselves, the surrounding matrix material is single-crystal metal or alloy. As a function of temperature, with a 2:1 He-to-vacancy ratio in a 5-at. % Ga fcc lattice, a 1.25-nm bubble is very stable up to about 1000 K. At 1000 K, the bubble distorts the surrounding lattice and precipitates a liquid zone, as is consistent with the phase diagram for the model material. Between 300 and 500 K, this same bubble relaxes slightly through interstitial emission. At 300 K, with a 2:1 He-to-vacancy ratio in a 2.5-at. % Ga fcc lattice, the Ga stabilization is less effective in the model to the point where the bubble distorts the local lattice and expands significantly. Similarly, at 300 K, if the He-to-vacancy ratio is increased to 3:1, there is significant local lattice distortion, as well as ejection of some He atoms into the lattice. The formation of new bubbles is not observed, because those events take place on a longer time scale than can be simulated with the present approach.

Valone, S. M.; Baskes, M. I. [Materials Science and Technology Division and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Martin, R. L. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2006-06-01T23:59:59.000Z

144

Energy Basics: Single-Crystalline Thin Film Used in Photovoltaics  

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

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,...

145

Test vehicle detector characterization system for the Boeing YAL-1 airborne laser  

E-Print Network (OSTI)

The test vehicle detector characterization system provides a convenient and efficient tool for rapidly evaluating the optical sensitivity of the GAP6012, GAP100, GAP300, and GAP1000 indium gallium arsenide detectors used ...

Steininger-Holmes, Jason Thomas

2008-01-01T23:59:59.000Z

146

Development of polycrystal GaAs solar cells. Quarterly technical progress report No. 1, January 15-April 30, 1979  

DOE Green Energy (OSTI)

The objective of this program is to develop a thin film GaAs solar cell technology with the potential of yielding cells with 12 to 15% efficiency and to develop thin film growth techniques which are compatible with the low cost production goal of $500/kW-peak. Progress is reported on a study of junction formation in large grain polycrystal GaAs; characterization of the electronic properties of polycrystal GaAs grown by MBE on low cost foreign substrates; optimizing the structure of AlGaAs-GaAs heterojunction Schottky barrier solar cells; and a variety of grain boundary measurements, including Scanning Light Microscopy (SLM), Deep Level Transient Spectroscopy (DLTS), SIMS, and temperature dependent resistivity.

Miller, D.L.; Cohen, M.J.; Harris, J.S. Jr.; Ballantyne, J.; Hoyte, A.; Stefanakos, E.

1979-05-01T23:59:59.000Z

147

Preparation of copper-indium-gallium-diselenide precursor films by electrodeposition for fabricating high efficiency solar cells  

DOE Patents (OSTI)

A photovoltaic cell exhibiting an overall conversion efficiency of 13.6% is prepared from a copper-indium-gallium-diselenide precursor thin film. The film is fabricated by first simultaneously electrodepositing copper, indium, gallium, and selenium onto a glass/molybdenum substrate (12/14). The electrodeposition voltage is a high frequency AC voltage superimposed upon a DC voltage to improve the morphology and growth rate of the film. The electrodeposition is followed by physical vapor deposition to adjust the final stoichiometry of the thin film to approximately Cu(In.sub.1-n Ga.sub.x)Se.sub.2, with the ratio of Ga/(In+Ga) being approximately 0.39.

Bhattacharya, Raghu N. (Littleton, CO); Hasoon, Falah S. (Arvada, CO); Wiesner, Holm (Golden, CO); Keane, James (Lakewood, CO); Noufi, Rommel (Golden, CO); Ramanathan, Kannan (Golden, CO)

1999-02-16T23:59:59.000Z

148

The design, construction, and testing of a nuclear fuel rod thermal simulation system to study gallium/Zircaloy interactions  

E-Print Network (OSTI)

The presence of gallium in weapons grade plutonium has raised many questions concerning its use in light water reactor (LWR) fuel rods. The biggest concern is that the gallium will migrate down the thermal gradient in the fuel rod and deposit on the inner surface of the clad, which could cause it to fail. In order to study these effects, a fuel rod thermal simulation system (FRTSS) has been developed to recreate the shape and magnitude of the temperature profile in pressurized water reactor (PWR) fuel rods. The system uses electrically heated simulated fuel rods inside of a large, natural convection heat exchanger that uses lead-bismuth eutectic (LBE) (45 <% Pb, 55 <% Bi) as the working fluid. The simulated rods consist of small diameter electric heaters, annular pellets of depleted uranium/cerium oxide doped with approximately 10 ppm of gallium, a small helium filled gap, and generic Zircaloy IV cladding. The system is controlled through a computer-based data acquisition system that is used to record temperature data and operate the various pieces of equipment. A simple mathematical model was used to design the heat exchanger and predict the temperature profile within the simulated rods. Results from system tests indicated that the mathematical model was capable of predicting heater surface temperatures within 6.15% +/- 1.82% and clad outer surface temperatures within 1.91% +/- 4.46%. In addition, the tests also revealed that the system could accurately simulate the temperature profiles of operating PWR fuel rods. Consequently, the FRTSS provides a safe and effective means for studying gallium migration in the fuel pellets and its subsequent interactions with Zircaloy IV.

Allison, Christopher Curtis

1999-01-01T23:59:59.000Z

149

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

150

Status of High Polarization DC High Voltage GaAs Photoguns  

SciTech Connect

This talk will review the state of the art of high polarization GaAs photoguns used worldwide. Subject matter will include drive laser technology, photocathode material, gun design, vacuum requirements and photocathode lifetime as a function of beam current. Recent results have demonstrated high current, 85% polarized beams with high reliability and long lifetime under operational conditions. Research initiatives for ensuring production of high average and peak current beams for future accelerator facilities such as ELIC and the ILC will be also discussed.

P. A. Adderley; J. Brittian; J. Clark; J. Grames; J. Hansknecht; J. McCarter; M. Poelker; M. L. Stutzman; R. Suleiman; K. E. L. Surles-Law

2007-08-01T23:59:59.000Z

151

Nano structuring of GaAs(100) surface using low energy ion irradiation  

SciTech Connect

Nanostructuring of semi insulating GaAs (100) has been observed after irradiation of 50 keV Ar{sup +} ion beam in a wide angular range of 0 deg. to 60 deg. with respect to surface normal. Atomic Force Microscopy (AFM) analysis shows the formation of nano dots at smaller angle of irradiation. At higher angle of irradiation, self organized ripples were developed on the surface. The rms roughness estimated from the AFM analysis shows exponential growth with angle of irradiation. In the high frequency regime, PSD analysis suggests that surface morphology of the irradiated samples is governed by the surface diffusion and mass transport dominated processes.

Kumar, Tanuj; Khan, S. A.; Verma, S.; Kanjilal, D. [Inter-university Accelerator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India)

2012-06-05T23:59:59.000Z

152

Reference Data for the Density and Viscosity of Liquid Cadmium, Cobalt, Gallium, Indium, Mercury, Silicon, Thallium, and Zinc  

Science Conference Proceedings (OSTI)

The available experimental data for the density and viscosity of liquid cadmium, cobalt, gallium, indium, mercury, silicon, thallium, and zinc have been critically examined with the intention of establishing both a density and a viscosity standard. All experimental data have been categorized into primary and secondary data according to the quality of measurement, the technique employed and the presentation of the data, as specified by a series of criteria. The proposed standard reference correlations for the density of liquid cadmium, cobalt, gallium, indium, silicon, thallium, and zinc are characterized by percent deviations at the 95% confidence level of 0.6, 2.1, 0.4, 0.5, 2.2, 0.9, and 0.7, respectively. In the case of mercury, since density reference values already exist, no further work was carried out. The standard reference correlations for the viscosity of liquid cadmium, cobalt, gallium, indium, mercury, silicon, thallium, and zinc are characterized by percent deviations at the 95% confidence level of 9.4, 14.0, 13.5, 2.1, 7.3, 15.7, 5.1, and 9.3, respectively.

Assael, Marc J.; Armyra, Ivi J.; Brillo, Juergen; Stankus, Sergei V.; Wu Jiangtao; Wakeham, William A. [Chemical Engineering Department, Aristotle University, 54124 Thessaloniki (Greece); Institut fuer Materialphysik im Weltraum, Deutsches Zentrum fuer Luft- und Raumfahrt, 51170 Koeln (Germany); Kutateladze Institute of Thermophysics, Siberian Brunch of the Russian Academy of Sciences, Lavrentyev ave. 1, 630090 Novosibirsk (Russian Federation); Center of Thermal and Fluid Science, School of Energy and Power Engineering, Xi'an Jiaotong University, Shaanxi 710049 (China); Chemical Engineering Department, Imperial College, London SW7 2BY (United Kingdom)

2012-09-15T23:59:59.000Z

153

Triggering GaAs lock-on switches with laser diode arrays  

SciTech Connect

Laser diode arrays have been used to trigger GaAs Photoconducting Semiconductor Switches (PCSS) charged to voltages of up to 60 kV and conducting currents of 580 A. The driving forces behind the use of laser diode arrays are compactness, elimination of complicated optics, and the ability to run at high repetition rates. Laser diode arrays are compactness, elimination of complicated optics, and the ability to run at high repetition rates. Laser diode arrays can trigger GaAs at high fields as the result of a new switching mode (lock-on) with very high carrier number gain. We have achieved switching of up to 10 MW in a 60 {Omega} system, with a pulse rise time of 500 ps. At 1.2 MW we have achieved repetition rates of 1 kHz with switch rise time of 500 ps for 10{sup 5} shots. The laser diode array used for these experiments delivers a 166 W pulse. In a single shot mode we have switched 4 kA with a flash lamp pumped laser and 600 A with the 166 W array. 7 refs., 5 figs.

Loubriel, G.M.; Buttram, M.T.; Helgeson, W.D.; McLaughlin, D.L.; O'Malley, M.W.; Zutavern, F.J. (Sandia National Labs., Albuquerque, NM (USA)); Rosen, A.; Stabile, P.J. (David Sarnoff Research Center, Princeton, NJ (USA))

1990-01-01T23:59:59.000Z

154

Charge collection in GaAs MESFETs fabricated in semi-insulating substrates  

SciTech Connect

Charge-collection in GaAs MESFETs fabricated in semi-insulating substrates is investigated. Current transients are measured at short times ({approximately} few picoseconds) after either an alpha-particle strike or a laser pulse. In addition, the total charge is obtained by integrating the collected current. Measurements show the existence of three mechanisms for charge collection: (1) the drift of holes and electrons to the gate and drain electrodes, respectively, (2) bipolar-gain, and (3) channel-modulation. The charge collected by drift of holes or electrons gives rise to an instrument limited response (within 20 ps) after a laser pulse. The bipolar-gain mechanism peaks in approximately {approximately} 200 ps and is responsible for most of the collected charge. The channel-modulation mechanism is responsible for charge collection at longer times. These results are different than previous results for MESFETs fabricated on top of a buried p-layer, where most of the charge was found to be collected by the channel-modulation mechanism. These results indicate that in order to harden GaAs transistors to single event upset, one must use techniques that reduce the effects of the bipolar-gain and channel-modulation mechanisms.

Schwank, J.R.; Sexton, F.W. [Sandia National Labs., Albuquerque, NM (United States); Weatherford, T.R.; McMorrow, D.; Knudson, A.R.; Melinger, J.S. [Naval Research Lab., Washington, DC (United States)

1995-12-01T23:59:59.000Z

155

I-V analysis of high-energy lithium-ion-irradiated Si and GaAs solar cells  

E-Print Network (OSTI)

Space-grade Si and GaAs solar cells were irradiated with 15 and 40 MeV lithium ions. Dark-IV analysis (with and without illumination) reveals differences in the effects of such irradiation on the different cell types

A. Meulenberg Jr; B. Jayashree; Ramani; M. C. Radhakrishna; A. K. Saif

2007-09-07T23:59:59.000Z

156

Development of polycrystal GaAs solar cells. Quarterly technical progress report No. 3, August 1, 1979-October 30, 1979  

DOE Green Energy (OSTI)

Progress at Rockwell International, Cornell University, and North Carolina A and T State University on the development of thin film polycrystal GaAs solar cells with a 10% conversion efficiency is described. Highlights include the growth of Ge on Fe substrates and the investigation of various grain boundary passivation schemes. (WHK)

Miller, D.L.; Cohen, M.J.; Harris, J.S. Jr.; Ballantyne, J.; Stefanakos, E.

1979-12-01T23:59:59.000Z

157

Induction, helicity, and alpha effect in a toroidal screw flow of liquid gallium  

SciTech Connect

We investigate experimentally induction mechanisms in a screw flow of gallium in a toroidal channel. The flow is nonstationary and operated in a spin-down regime: the channel (and fluid) are initially set into solid body rotation; as the channel is stopped the fluid is set into strong helical motion by diverters located inside the channel. In this study, we put a particular emphasis on the induction generated by these helical motions, which are expected to develop over the entire range of turbulent scales. We apply an external magnetic field either perpendicular to the channel axis parallel to it. At large scales the nonlinear induction mechanisms are associated with the Parker stretch and twist effect and with the expulsion due to overall rotation. Induction mechanisms can also originate in the small scale helicity as in the alpha induction effect of mean-field magnetohydrodynamics. Our measurements yield an upper bound for the alpha coefficient, significantly lower than estimates based on dimensional analysis. We discuss the consequences of our observations for the engineering of homogeneous dynamos in the laboratory.

Stepanov, R.; Denisov, S.; Noskov, V. [Institute of Continuous Media MechanicsKorolyov 1, 614061 Perm (Russian Federation); Volk, R.; Frick, P.; Pinton, J.-F. [Laboratoire de Physique de l'Ecole Normale Superieur de Lyon, CNRS UMR5672, 46 allee d'Italie, 69007 Lyon (France)

2006-04-15T23:59:59.000Z

158

Surface Composition, Work Function, and Electrochemical Characteristics of Gallium-Doped Zinc Oxide  

Science Conference Proceedings (OSTI)

Gallium-doped zinc oxide (GZO) possesses the electric conductivity, thermal stability, and earth abundance to be a promising transparent conductive oxide replacement for indium tin oxide electrodes in a number of molecular electronic devices, including organic solar cells and organic light emitting diodes. The surface chemistry of GZO is complex and dominated by the hydrolysis chemistry of ZnO, which influences the work function via charge transfer and band bending caused by adsorbates. A comprehensive characterization of the surface chemical composition and electrochemical properties of GZO electrodes is presented, using both solution and surface adsorbed redox probe molecules. The GZO surface is characterized using monochromatic X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy after the following pretreatments: (i) hydriodic acid etch, (ii) potassium hydroxide etch, (iii) RF oxygen plasma etching, and (iv) high-vacuum argon-ion sputtering. The O 1s spectra for the GZO electrodes have contributions from the stoichiometric oxide lattice, defects within the lattice, hydroxylated species, and carbonaceous impurities, with relative near-surface compositions varying with pretreatment. Solution etching procedures result in an increase of the work function and ionization potential of the GZO electrode, but yield different near surface Zn:Ga atomic ratios, which significantly influence charge transfer rates for a chemisorbed probe molecule. The near surface chemical composition is shown to be the dominant factor in controlling surface work function and significantly influences the rate of electron transfer to both solution and tethered probe molecules.

Ratcliff, E. L.; Sigdel, A. K.; Macech, M. R.; Nebesny, K.; Lee, P. A.; Ginley, D. S.; Armstrong, N. R.; Berry, J. J.

2012-06-30T23:59:59.000Z

159

The Influence of Lewis Acid/Base Chemistry on the Removal of Gallium by Volatility from Weapons-Grade Plutonium Dissolved in Molten Chlorides  

Science Conference Proceedings (OSTI)

It has been proposed that GaCl{sub 3} can be removed by direct volatilization from a Pu-Ga alloy that is dissolved in a molten chloride salt. Although pure GaCl{sub 3} is quite volatile (boiling point: 201 deg. C), the behavior of GaCl{sub 3} dissolved in chloride salts is quite different because of solution effects and is critically dependent upon the composition of the solvent salt (i.e., its Lewis acid/base character). In this technical note, the behavior of gallium in prototypical Lewis acid and Lewis base salts is contrasted. It is found that gallium volatility is suppressed in basic melts and promoted in acidic melts. These results have an important influence on the potential for simple gallium removal in molten salt systems.

Williams, David F.; Cul, Guillermo D. del [Oak Ridge National Laboratory (United States); Toth, Louis M. [Electrochemical Systems (United States); Collins, Emory D. [Oak Ridge National Laboratory (United States)

2001-12-15T23:59:59.000Z

160

Optical Tech Div 1999 - Technical Highlights - Figure 6  

Science Conference Proceedings (OSTI)

... of wavelength are shown for six materials: germanium (Ge), silicon (Si), gallium arside (GaAs), magnesium oxide (MgO), lithium fluoride (LiF), and ...

Note: This page contains sample records for the topic "gallium arsenide gaas" from the National Library of EnergyBeta (NLEBeta).
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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

Optical Technology Division 1999 - Technical Highlights ...  

Science Conference Proceedings (OSTI)

... of wavelength are shown for six materials: germanium (Ge), silicon (Si), gallium arside (GaAs), magnesium oxide (MgO), lithium fluoride (LiF), and ...

162

Energy distribution of nonequilibrium electrons and optical phonons in GaAs under band-to-band pumping by intense short pulses of light  

SciTech Connect

Deviation from the Fermi distribution of nonequilibrium electrons and distribution of 'hot' optical phonons in GaAs under band-to-band pumping by picosecond pulses of light are calculated.

Altybaev, G. S.; Kumekov, S. E., E-mail: skumekov@mail.ru; Mahmudov, A. A. [Satpaev Kazakh National Technical University (Kazakhstan)

2009-03-15T23:59:59.000Z

163

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

164

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

165

Picosecond radiation-induced current transients in digital GaAs MESFETs  

Science Conference Proceedings (OSTI)

Picosecond-resolution measurements of the current transients produced when energetic ions (alpha particles) interact with high-speed digital GaAs MESFETs are presented. Measurements as a function of device bias and temperature reveal the presence of several different contributions to the charge-collection transients, ranging in time scale from picoseconds to microseconds. The effects of permanent radiation damage are found to degrade device performance to the extent that reliable measurement of the ion-induced transients is difficult and, in many cases, impossible. The use of above-bandgap picosecond laser excitation is revealed to be a viable alternative to the use of heavy ions for characterization of the charge-collection dynamics in semiconductor devices.

McMorrow, D.; Campbell, A.B.; Knudson, A.R.; Weatherford, T.R.

1992-05-22T23:59:59.000Z

166

Single-event dynamics of high-performance HBTs and GaAs MESFETs  

SciTech Connect

Picosecond charge-collection transients measured for GaAs/AlGaAs HBTs following 3.0 MeV [alpha]-particle and 620 nm picosecond laser excitation reveal charge-collection efficiencies up to twenty-eight times smaller than for GaAs MESFETs, with [approximately]90% of the charge collected within 75 ps of the ionizing event. The small charge-collection efficiency of the HBTs is a consequence of the ultrafast charge-collection dynamics in these devices. The authors show that picosecond laser excitation reproduces nicely the ion-induced transients, providing a valuable tool for the investigation of charge-collection and SEU phenomena in these devices.

McMorrow, D.; Melinger, J.S.; Campbell, A.B. (Naval Research Lab., Washington, DC (United States)); Weatherford, T.; Knudson, A.R.; Tran, L.H.

1993-12-01T23:59:59.000Z

167

Charge collection in GaAs MESFET circuits using a high energy microbeam  

Science Conference Proceedings (OSTI)

The mechanisms responsible for single event upsets can be studied more realistically in transistors that are part of an integrated test circuit than in single isolated test transistors with fixed biases on all the nodes. Both energetic, heavy ions and focused, pulsed laser light were used to generate transient voltages at a number of different nodes in a GaAs MESFET integrated test circuit. Three-dimensional maps of charge collection regions were generated with the use of the scanning ion microprobe at Gesellschaft fuer Schwerionenforschung (GSI). The results showed that charge was collected from all areas of the circuit, but with different efficiencies at different injection sites. Regions not covered with metal were exposed to pulsed laser light. The resulting transients had pulse shapes similar to those generated by ions and amplitudes that also depended on ion strike location. These results illustrate the usefulness of the ion microprobe technique for obtaining spatial and temporal information about SEU in integrated circuits.

Buchner, S.; Weatherford, T.; Knudson, A.; McDonald, P. [SFA, Landover, MD (United States); Campbell, A.B.; McMorrow, D. [Naval Research Lab., Washington, DC (United States); Fischer, B.; Metzger, S.; Schloegl, M. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)

1996-12-01T23:59:59.000Z

168

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

169

Excitation Power Dependence Of Photoluminescence From GaAs Quantum Dot Prepared By Droplet Epitaxy Method  

Science Conference Proceedings (OSTI)

GaAs quantum dot (QD) was grown by droplet epitaxy (DE) method and the excitation power dependence of photoluminescence (PL) were carried out. To investigate the effect of annealing temperature on QDs optical properties, the two step RTA process was carried out in a various temperature range from 800 to 1000 deg. C. As the thermal annealing temperature increases, the PL peak position is blue-shifted due to the change of the composition and size distribution of QDs, and the highest PL intensity is observed at the sample annealed at 900 deg. C. The integrated PL intensity (I{sub PL}) is plotted against the excitation density in a log-log scale and the slope was calculated.

Choi, H. Y.; Kim, D. Y.; Cho, M. Y.; Kim, G. S.; Jeon, S. M.; Yim, K. G.; Kim, M. S.; Leem, J. Y. [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Gimhae (Korea, Republic of); Lee, D. Y. [Epi-manufacturing Technology, Samsung LED Co., Ltd., Suwon (Korea, Republic of); Kim, J. S. [Division of Advanced Materials Engineering, Chonbuk National University, Jeonju (Korea, Republic of); Kim, J. S. [Department of Physics, Yeungnam University, Gyeongsan (Korea, Republic of); Son, J. S. [Department of Visual Optics, Kyungwoon University, Gumi (Korea, Republic of); Lee, J. I. [Advanced Instrument Technology Center, Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2011-12-23T23:59:59.000Z

170

Deep-Level Transient Spectroscopy in InGaAsN Lattice-Matched to GaAs: Preprint  

Science Conference Proceedings (OSTI)

This conference paper describes the deep-level transient spectroscopy (DLTS) measurements have been performed on the quaternary semiconductor InGaAsN. A series of as-grown, metal-organic chemical vapor deposited samples having varying composition were grown and measured. A GaAs sample was used as a baseline for comparison. After adding only In to GaAs, we did not detect significant additional defects; however, adding N and both N and In led to larger hole-trap peaks and additional electron-trap peaks in the DLTS data. The samples containing about 2% N, with and without about 6% In, had electron traps with activation energies of about 0.2 and 0.3 eV. A sample with 0.4% N had an electron trap with an activation energy of 0.37 eV.

Johnston, S. W.; Ahrenkiel, R. K.; Friedman, D. J.; Kurtz, S. R.

2002-05-01T23:59:59.000Z

171

Nuclear fuels technologies: Thermally induced gallium removal system (TIGRS), fiscal year 1998 research and development test plan  

SciTech Connect

This document details the research and development (R and D) activities that will be conducted in Fiscal Year 1998 (FY98) by the Thermally Induced Gallium Removal System (TIGRS) team for the Department of Energy Office of Fissile Materials Disposition. This work is a continuation and extension of experimental activities that have been conducted in support of using weapons-derived plutonium in the fabrication of mixed-oxide (MOX) nuclear fuel for reactor-based plutonium disposition. The ultimate purpose of this work is to demonstrate adequate Thermally Induced Gallium Removal with a prototypic system. This Test Plan presents more than the FY98 R and D efforts in order to frame the Task in its entirety. To achieve the TIGRS Program objectives, R and D activities during the next two years will be focused on (1) process development leading to a prototypic TIGRS design, and (2) prototypic TIGRS design and testing leading to and including a prototypic demonstration of TIGRS operation. Both the process development and system testing efforts will consist of a series of surrogate-based cold tests and plutonium-based hot tests. Some of this testing has already occurred and will continue into FY99.

Buksa, J.J.; Butt, D.P.; Chidester, K.; DeMuth, S.F.; Havrilla, G.J.; James, C.A.; Kolman, D.G.

1997-12-24T23:59:59.000Z

172

Formation of copper-indium-selenide and/or copper-indium-gallium-selenide films from indium selenide and copper selenide precursors  

DOE Patents (OSTI)

Liquid-based indium selenide and copper selenide precursors, including copper-organoselenides, particulate copper selenide suspensions, copper selenide ethylene diamine in liquid solvent, nanoparticulate indium selenide suspensions, and indium selenide ethylene diamine coordination compounds in solvent, are used to form crystalline copper-indium-selenide, and/or copper indium gallium selenide films (66) on substrates (52).

Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); Van Hest, Maikel (Lakewood, CO); Ginley, David S. (Evergreen, CO); Nekuda, Jennifer A. (Lakewood, CO)

2011-11-15T23:59:59.000Z

173

Gallium-Nitride Transistors for High-Efficiency Industrial Power Supplies, Phase 1: State of Semiconductor Development and Industrial Power Supply Market  

Science Conference Proceedings (OSTI)

This white paper describes recent advancements in the development of Gallium-Nitride (GaN) transistors for power conversion applications. This wide bandgap semiconductor has the potential to reduce losses and improve performance of power converters. The industrial power supply market is described and the application of GaN to power conversion in this segment is introduced for future work.

2013-12-23T23:59:59.000Z

174

dc field-emission analysis of GaAs and plasma-source ion-implanted stainless steel  

DOE Green Energy (OSTI)

Field-emission studies have been performed on a GaAs wafer and a sample of its stainless-steel (SS) support electrode that are part of a photocathode gun for the 10 kW Upgrade infrared free electron laser at Jefferson Lab. The objective of the studies presented here is to characterize the effect of both the cleanliness of the wafer and the plasma-source ion-implanted layer on the electrode to suppress field emission. Field emission is the limiting factor to achieve the required 6 MV/m at the surface of the wafer. Potential field emitters are first located on the surface of 1 in. diameter samples with a dc scanning field-emission microscope at 60 MV/m, then each emitter is characterized in a scanning electron microscope equipped with an energy dispersive spectrometer. The GaAs wafer was hydrogen cleaned before the study. The results show three emitters caused by indium contamination during wafer handling. The GaAs wafer thus shows good high-voltage characteristics and the need to maintain cleanliness during handling. The SS sample is hand polished with diamond paste to a 1-m surface finish, then implanted with N2/SiO2 in a plasma-source ion-implantation chamber in preparation for the field-emission studies.

C. Hernandez; T. Wang; T. Siggins; D. Bullard; H. F. Dylla; C. Reece; N. D. Theodore; D. M. Manos

2003-06-01T23:59:59.000Z

175

High efficiency thin-film GaAs solar cells. First interim report, March 1--August 30, 1977  

DOE Green Energy (OSTI)

The objective is to demonstrate the feasibility of producing high-efficiency (15% or greater) thin-film GaAs solar cells with costs suitable for terrestrial solar electric power generation. The approach is that of growing GaAs by organio-metallic chemical vapor deposition on recrystallized germanium (Ge) films previously deposited on metal substrates and fabricating AMOS (Antireflecting Metal-Oxide-Semiconductor) solar cells on the GaAs. Previously it had been determined that a water vapor-grown native oxide (temperature = 25/sup 0/C) was the most useful native oxide for AMOS cells. A new chemical surface preparation prior to oxide growth led to more uniform oxides and reduced interface contamination, yielding lower reverse saturation current densities, a near-unity diode ideality factor, and better reproducibility. Substituting silver (Ag) for gold metallization showed no change in starting cell efficiency, but did greatly improve high temperature stability of the AMOS solar cell. A new study was completed on antireflection coatings on AMOS GaAs solar cells, taking into account the spectral response of the cell and nature of the solar spectra, and the results submitted for publication. XPS (X-ray Photoelectron Spectroscopy) studies had found earlier that the more efficient native oxides had primarily As/sub 2/O/sub 3/ and Ga/sub 2/O/sub 3/ with little GaAsO/sub 4/. A new chemical step etching was developed which can be used to profile the oxide in 5- to 7-A/sup 0/ steps without modifying the oxide chemistry as does ion sputtering. A new Schottky barrier structure is described which can give cell efficiencies up to 16% without oxide interfacial layer effects and 20 to 22% with a moderate interfacial layer effect. AMOS solar cells fabricated on sliced polycrystalline GaAs wafers with 100- to 500-..mu..m grains using Sb/sub 2/O/sub 3/ deposited oxides showed 14% cell efficiency compared to 16.2% in a region with few grains.

Stirn, R.J.

1977-12-01T23:59:59.000Z

176

Arsenides, Phosphides - Programmaster.org  

Science Conference Proceedings (OSTI)

May 27, 2010 ... Besides the known challenges of III/V on IV heteroepitaxy, like charge .... Although carbon tetrahalogenides, such as CBr4, CCl4, and CBrCl3, ...

177

Exposure of GaAs to atomic hydrogen for cleaning prior to NEA photocathode activation  

DOE Green Energy (OSTI)

Creating an atomically clean semiconductor surface is an essential step in preparing negative electron affinity (NEA) photoemission cathodes. While bulk GaAs can be satisfactorily cleaned by chemical etching and in situ heat cleaning, many high polarization electron source materials are either much too thin, or have oxides and carbides which are too tightly bound, to be cleaned by these methods. Some polarized source candidate materials may be degraded during the heat cleaning step. It is well established that the exposure of many III-V, II-VI, and elemental semiconductors to atomic hydrogen, typically at elevated temperatures, produces semiconductor surfaces free of contamination. Furthermore, this cleaning, possibly followed by thermal annealing, leaves surfaces which show sharp LEED patterns, indicating good stoichiometry and surface order. Atomic hydrogen cleaning should eliminate the chemical etching step, and might reduce the temperature and/or temperature-time product presently used in forming NEA cathodes. The process is readily adaptable to in situ use in ultrahigh vaccum.

Sinclair, C.K.; Poelker, B.M.; Price, J.S. [Jefferson Lab., Newport News, VA (United States)

1998-12-31T23:59:59.000Z

178

HfO2 Gate Dielectric on (NH4)2S Passivated (100) GaAs Grown by Atomic Layer Deposition  

Science Conference Proceedings (OSTI)

The interface between hafnium oxide grown by atomic layer deposition and (100) GaAs treated with HCl cleaning and (NH{sub 4}){sub 2}S passivation has been characterized. Synchrotron radiation photoemission core level spectra indicated successful removal of the native oxides and formation of passivating sulfides on the GaAs surface. Layer-by-layer removal of the hafnia film revealed a small amount of As{sub 2}O{sub 3} formed at the interface during the dielectric deposition. Traces of arsenic and sulfur out-diffusion into the hafnia film were observed after a 450 C post-deposition anneal, and may be the origins for the electrically active defects. Transmission electron microscopy cross section images showed thicker HfO{sub 2} films for a given precursor exposure on S-treated GaAs versus the non-treated sample. In addition, the valence-band and the conduction-band offsets at the HfO{sub 2}/GaAs interface were deduced to be 3.18 eV and a range of 0.87-0.97 eV, respectively. It appears that HCl+(NH{sub 4})2{sub S} treatments provide a superior chemical passivation for GaAs and initial surface for ALD deposition.

Chen, P.T.; /Stanford U., Materials Sci. Dept.; Sun, Y.; /SLAC, SSRL; Kim, E.; McIntyre, P.C.; /Stanford U., Materials Sci. Dept.; Tsai, W.; Garner, M.; /Intel, Santa Clara; Pianetta, P.; /SLAC, SSRL; Nishi, Y.; /Stanford U., Elect. Eng. Dept.; Chui, C.O.; /UCLA

2007-09-28T23:59:59.000Z

179

Chemical thermodynamics of nuclear materials. IX. High temperature heat capacity of plutonium-3. 2 at. % gallium alloy  

Science Conference Proceedings (OSTI)

The heat capacity of delta-stabilized plutonium (Pu - 3.2 at. % Ga) has been determined from 330 to 700/sup 0/K by an adiabatic calorimeter. The heat capacity for this alloy may be expressed by: Cp (Pu-3.2 at. % Ga)/(J K/sup -1/ mol/sup -1/) = 39.249 - 0.0264 (T/K) + 3.595 x 10/sup 5/ (T/K)/sup 2/ - 2.506 x 10/sup 5/ (K/T)/sup 2/. It was found that a large contribution to the heat capacity is due to the electronic heat capacity. The thermal functions for this plutonium-gallium alloy are calculated to 700/sup 0/K.

Adams, R.O.; Oetting, F.L.

1982-01-01T23:59:59.000Z

180

Compact, Interactive Electric Vehicle Charger: Gallium-Nitride Switch Technology for Bi-directional Battery-to-Grid Charger Applications  

SciTech Connect

ADEPT Project: HRL Laboratories is using gallium nitride (GaN) semiconductors to create battery chargers for electric vehicles (EVs) that are more compact and efficient than traditional EV chargers. Reducing the size and weight of the battery charger is important because it would help improve the overall performance of the EV. GaN semiconductors process electricity faster than the silicon semiconductors used in most conventional EV battery chargers. These high-speed semiconductors can be paired with lighter-weight electrical circuit components, which helps decrease the overall weight of the EV battery charger. HRL Laboratories is combining the performance advantages of GaN semiconductors with an innovative, interactive battery-to-grid energy distribution design. This design would support 2-way power flow, enabling EV battery chargers to not only draw energy from the power grid, but also store and feed energy back into it.

2010-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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.


181

GaAs structures with InAs and As quantum dots produced in a single molecular beam epitaxy process  

Science Conference Proceedings (OSTI)

Epitaxial GaAs layers containing InAs semiconductor quantum dots and As metal quantum dots are grown by molecular beam epitaxy. The InAs quantum dots are formed by the Stranskii-Krastanow mechanism, whereas the As quantum dots are self-assembled in the GaAs layer grown at low temperature with a large As excess. The microstructure of the samples is studied by transmission electron microscopy. It is established that the As metal quantum dots formed in the immediate vicinity of the InAs semiconductor quantum dots are larger in size than the As quantum dots formed far from the InAs quantum dots. This is apparently due to the effect of strain fields of the InAs quantum dots upon the self-assembling of As quantum dots. Another phenomenon apparently associated with local strains around the InAs quantum dots is the formation of V-like defects (stacking faults) during the overgrowth of the InAs quantum dots with the GaAs layer by low-temperature molecular beam epitaxy. Such defects have a profound effect on the self-assembling of As quantum dots. Specifically, on high-temperature annealing needed for the formation of large-sized As quantum dots by Ostwald ripening, the V-like defects bring about the dissolution of the As quantum dots in the vicinity of the defects. In this case, excess arsenic most probably diffuses towards the open surface of the sample via the channels of accelerated diffusion in the planes of stacking faults.

Nevedomskii, V. N., E-mail: nevedom@mail.ioffe.ru; Bert, N. A.; Chaldyshev, V. V., E-mail: Chald@gvg.ioffe.ru [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Preobrazhenskii, V. V.; Putyato, M. A.; Semyagin, B. R. [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Division (Russian Federation)

2009-12-15T23:59:59.000Z

182

Multi-junction, monolithic solar cell using low-band-gap materials lattice matched to GaAs or Ge  

DOE Patents (OSTI)

A multi-junction, monolithic, photovoltaic solar cell device is provided for converting solar radiation to photocurrent and photovoltage with improved efficiency. The solar cell device comprises a plurality of semiconductor cells, i.e., active p/n junctions, connected in tandem and deposited on a substrate fabricated from GaAs or Ge. To increase efficiency, each semiconductor cell is fabricated from a crystalline material with a lattice constant substantially equivalent to the lattice constant of the substrate material. Additionally, the semiconductor cells are selected with appropriate band gaps to efficiently create photovoltage from a larger portion of the solar spectrum. In this regard, one semiconductor cell in each embodiment of the solar cell device has a band gap between that of Ge and GaAs. To achieve desired band gaps and lattice constants, the semiconductor cells may be fabricated from a number of materials including Ge, GaInP, GaAs, GaInAsP, GaInAsN, GaAsGe, BGaInAs, (GaAs)Ge, CuInSSe, CuAsSSe, and GaInAsNP. To further increase efficiency, the thickness of each semiconductor cell is controlled to match the photocurrent generated in each cell. To facilitate photocurrent flow, a plurality of tunnel junctions of low-resistivity material are included between each adjacent semiconductor cell. The conductivity or direction of photocurrent in the solar cell device may be selected by controlling the specific p-type or n-type characteristics for each active junction.

Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO); Friedman, Daniel J. (Lakewood, CO)

2001-01-01T23:59:59.000Z

183

Highly polarized emission in spin resolved photoelectron spectroscopy of alpha-Fe(001)/GaAs(001)  

SciTech Connect

Highly spin-polarized sources of electrons, Integrated into device design, remain of great interest to the spintronic and magneto-electronic device community Here, the growth of Fe upon GaAs(001) has been studied with photoelectron spectroscopy (PES), including Spin Resolved PES. Despite evidence of atomic level disorder such as intermixing, an over-layer with the spectroscopic signature of alpha-Fe(001), with a bcc real space ordering, Is obtained The results will be discussed in light of the possibility of using such films as a spin-polarized source in device applications.

Tobin, James; Yu, Sung Woo; Morton, Simon; Waddill, George; Thompson, Jamie; Neal, James; Spangenberg, Matthais; Shen, T.H.

2009-05-19T23:59:59.000Z

184

The Influence of High-Energy Lithium Ion Irradiation on Electrical Characteristics of Silicon and GaAs Solar Cells  

E-Print Network (OSTI)

Space-grade Si and GaAs solar cells were irradiated with 15 & 40 MeV Li ions. Illuminated (AM0 condition) and unilluminated I-V curves reveal that the effect of high-energy Li ion irradiation has produced similar effects to that of proton irradiation. However, an additional, and different, defect mechanism is suggested to dominate in the heavier-ion results. Comparison is made with proton-irradiated solar-cell work and with non-ionizing energy-loss (NIEL) radiation-damage models.

B. Jayashree; Ramani; M. C. Radhakrishna; Anil Agrawal; Saif Ahmad Khan; A. Meulenberg

2006-10-20T23:59:59.000Z

185

Direct measurement of the spin gaps in a gated GaAs two-dimensional electron gas  

E-Print Network (OSTI)

. For the low-field regime where ?s destroyed by the disorder, and there is no spin-splitting for the magnetic field less than Bc. As shown in Figure 7, the ‘spin gap’ measured by the conventional activation energy studies... linearly to zero at a critical magnetic field Bc ~ 3.47 T. The spin gap is expected to have the form ?s = g0?BB + Eex = g * ?BB [12], where Eex is the many-body exchange energy which lifts the g-factor from its bare value (0.44 in GaAs) to its enhanced...

Huang, Tsai-Yu; Liang, Chi-Te; Chen, Yang Fang; Simmons, Michelle Y; Kim, Gil-Ho; Ritchie, David A

2013-03-25T23:59:59.000Z

186

AlGaAs/GaAs nano-hetero-epitaxy on a patterned GaAs substrate by MBE  

SciTech Connect

An AlGaAs/GaAs resonant tunneling diode (RTD) with submicron size was fabricated on {l_brace}111{r_brace} oblique facets of GaAs with selective MBE. The method is based on the fact that a certain facet structure is formed on a patterned substrate in selective MBE because the growth rate depends strongly on the facet structure. The fabrication of a double-barrier structure was attempted on a {l_brace}111{r_brace}B facet. The current-voltage characteristics of the sample showed negative differential resistance at 77K demonstrating that we have achieved an RTD on a submicron facet.

Nishiwaki, T.; Yamaguchi, M.; Sawaki, N. [Department of Electronics, Nagoya University, Chikusa-ku, Nagoya, 464-8603 (Japan)

2007-04-10T23:59:59.000Z

187

Outdoor Testing of GaInP2/GaAs Tandem Cells with Top Cell Thickness Varied  

DOE Green Energy (OSTI)

In this study, we measure the performance of GaInP2/GaAs tandem cells under direct beam sunlight outdoors in order to quantify their sensitivity to both spectral variation and GaInP2 top-cell thickness. A set of cells with five different top-cell thicknesses was mounted on a two-axis tracker with the incident sunlight collimated to exclude all except the direct beam. Current-voltage (I-V) curves were taken throughout the course of several days, along with measurements of the direct solar spectrum. Our two major conclusions are: (1) GaInP2/GaAs tandem cells designed for either the ASTM G-173 direct (G-173D) spectrum or the "air mass 1.5 global" (AM1.5G) spectrum perform the best, and (2) cells can be characterized indoors and modeled using outdoor spectra with the same result. These results are equally valid for GaInP2/GaAs/Ge triple-junction cells.

McMahon, W. E.; Emergy, K. E.; Friedman, D. J.; Ottoson, L.; Young, M. S.; Ward, J. S.; Kramer, C. M.; Duda, A.; Kurtz, S.

2005-08-01T23:59:59.000Z

188

On-Sun Comparison of GaInP2/GaAs Tandem Cells with Top Cell Thickness Varied  

DOE Green Energy (OSTI)

This study compares the on-sun performance of a set of GaInP2/GaAs tandem cells with different GaInP2 top-cell thicknesses. Because high-efficiency III-V cells are best suited to concentrating photovoltaic (CPV) applications, the cells were mounted on a two-axis tracker with the incident sunlight collimated to exclude all except the direct beam. Current-voltage (I-V) curves were taken throughout the course of several days, along with measurements of the direct solar spectrum. Our two major conclusions are: (1) GaInP2/GaAs tandem cells designed for an ''air mass 1.5 global'' (AM 1.5G) or a ''low aerosol optical depth'' (Low AOD) spectrum perform the best, and (2) cells can be characterized indoors and modeled using outdoor spectra to predict the correct result. These results are equally valid for GaInP2/GaAs/Ge triple-junction cells.

McMahon, W. E.; Emery, K. E.; Friedman, D. J.; Ottoson, L.; Young, M. S.; Ward, J. S.; Kramer, C. M.; Duda, A.; Kurtz, S.

2005-02-01T23:59:59.000Z

189

C-V characteristics of epitaxial germanium metal-oxide-semiconductor capacitor on GaAs substrate with ALD Al2O3 dielectric  

Science Conference Proceedings (OSTI)

Epitaxial germanium metal-oxide-semiconductor capacitors (MOSCAP) were fabricated on GaAs substrate using atomic layer deposited Al"2O"3 gate dielectric with surface treatments including pure HF and HF plus rapid thermal oxidation (RTO). The electrical ... Keywords: ALD Al2O3, CMOS integration, Ge MOSCAP, Ge epitaxial film, RTO

Shih Hsuan Tang; Chien I. Kuo; Hai Dang Trinh; Mantu Hudait; Edward Yi Chang; Ching Yi Hsu; Yung Hsuan Su; Guang-Li Luo; Hong Quan Nguyen

2012-09-01T23:59:59.000Z

190

Interfaces of high-k dielectrics on GaAs: Their common features and the relationship with Fermi level pinning (Invited Paper)  

Science Conference Proceedings (OSTI)

Numerous metal oxides have been studied worldwide as possible high-k gate dielectric candidates for MOS devices on alternative semiconductor materials (Ge, III/V compounds). We will discuss thermal and plasma-enhanced atomic layer deposition (ALD) of ... Keywords: Atomic layer deposition ALD, Atomistic modeling, GaAs MOS, High-k

Matty Caymax; Guy Brammertz; Annelies Delabie; Sonja Sioncke; Dennis Lin; Marco Scarrozza; Geoffrey Pourtois; Wei-E Wang; Marc Meuris; Marc Heyns

2009-07-01T23:59:59.000Z

191

Electrical properties and interfacial chemical environments of in situ atomic layer deposited Al2O3 on freshly molecular beam epitaxy grown GaAs  

Science Conference Proceedings (OSTI)

Interfacial chemical analyses and electrical characterization of in situ atomic layer deposited (ALD) Al"2O"3 on freshly molecular beam epitaxy (MBE) grown n- and p- GaAs (001) with a (4x6) surface reconstruction are performed. The capacitance-voltage ... Keywords: Atomic layer deposition, III-V compound semiconductor, Molecular beam epitaxy

Y. H. Chang; M. L. Huang; P. Chang; C. A. Lin; Y. J. Chu; B. R. Chen; C. L. Hsu; J. Kwo; T. W. Pi; M. Hong

2011-04-01T23:59:59.000Z

192

SUPPRESSION OF ANTIPHASE DISORDER IN GaAs GROWN ON RELAXED GeSi BUFFERS BY METAL-ORGANIC CHEMICAL VAPOR DEPOSITION  

E-Print Network (OSTI)

sublattices, the zinc-blende crystal structure possesses lower symmetry than the diamond cubic structure of wrong nearest-neighbor bonds, they are electrically active defects responsible for scattering and non of antiphase disorder requires control of the substrate surface structure prior to GaAs growth. The usage

193

Electrical Bias as an Alternate Method for Reproducible Measurement of Copper Indium Gallium Diselenide (CIGS) Photovoltaic Modules: Preprint  

DOE Green Energy (OSTI)

Light-to-dark metastable changes in thin-film photovoltaic (PV) modules can introduce uncertainty when measuring module performance on indoor flash testing equipment. This study describes a method to stabilize module performance through forward-bias current injection rather than light exposure. Measurements of five pairs of thin-film copper indium gallium diselenide (CIGS) PV modules indicate that forward-bias exposure maintained the PV modules at a stable condition (within 1%) while the unbiased modules degraded in performance by up to 12%. It was additionally found that modules exposed to forward bias exhibited stable performance within about 3% of their long-term outdoor exposed performance. This carrier-injection method provides a way to reduce uncertainty arising from fast transients in thin-film module performance between the time a module is removed from light exposure and when it is measured indoors, effectively simulating continuous light exposure by injecting minority carriers that behave much as photocarriers do. This investigation also provides insight into the initial light-induced transients of thin-film modules upon outdoor deployment.

Deline, C.; Stokes, A.; Silverman, T. J.; Rummel, S.; Jordan, D.; Kurtz, S.

2012-08-01T23:59:59.000Z

194

Derived reference doses for three compounds used in the photovoltaics industry: Copper indium diselenide, copper gallium diselenide, and cadmium telluride  

DOE Green Energy (OSTI)

Polycrystalline thin-film photovoltaic modules made from copper indium diselenide (CIS), copper gallium diselenide (CGS), and cadmium telluride (CdTe) arc nearing commercial development. A wide range of issues are being examined as these materials move from the laboratory to large-scale production facilities to ensure their commercial success. Issues of traditional interest include module efficiency, stability and cost. More recently, there is increased focus given to environmental, health and safety issues surrounding the commercialization of these same devices. An examination of the toxicological properties of these materials, and their chemical parents is fundamental to this discussion. Chemicals that can present large hazards to human health or the environment are regulated often more strictly than those that are less hazardous. Stricter control over how these materials are handled and disposed can increase the costs associated with the production and use of these modules dramatically. Similarly, public perception can be strongly influenced by the inherent biological hazard that these materials possess. Thus, this report: presents a brief background tutorial on how toxicological data are developed and used; overviews the toxicological data available for CIS, CGS and CdTe; develops ``reference doses`` for each of these compounds; compares the reference doses for these compounds with those of their parents; discusses the implications of these findings to photovoltaics industry.

Moskowitz, P.D.; Bernholc, N.; DePhillips, M.P.; Viren, J.

1995-07-06T23:59:59.000Z

195

Low energy solar neutrino experiments: The Soviet American Gallium Experiment (SAGE). Final report, August 12, 1988--October 31, 1994  

SciTech Connect

Two {sup 71}Ga experiments are currently in operation. The first is the 60 ton Soviet American Gallium Experiment (SAGE) at Baksan, which has recently reported a signal level of 73+18/{minus}16(stat)+5/{minus}7(syst) SNU; the second is the 30 ton GALLEX experiment at Gran Sasso, which sees 87{+-}14{+-}7 SNU. Both results are consistent, and both suggest a neutrino flux level low compared to the total expected from standard solar model calculations. It is not possible, however, to make a case for flux levels lower than the p-p prediction. Assuming the experiments are correct (Neutrino source calibrations are planned for both SAGE and GALLEX in the near future.), it is not at all clear yet whether the answer lies with the neutrino physics, solar physics, or a combination of both. Nevertheless, though solar model effects cannot be ruled out, if the Homestake and Kamiokande results are taken at face value, then these two experiments alone imply that neutrino oscillations or some similar particle physics result must be present to some degree. This report reviews the SAGE experiment and recent results. Non-radiochemical experiments are also discussed, with an emphasis on the Kamiokande water Cerenkov results.

NONE

1995-04-01T23:59:59.000Z

196

Molecular Beam Epitaxial Growth of Bi2Te3 and Sb2Te3 Topological Insulators on GaAs (111) Substrates: A Potential Route to Fabricate Topological Insulator p-n Junction  

E-Print Network (OSTI)

High quality Bi2Te3 and Sb2Te3 topological insulators films were epitaxially grown on GaAs (111) substrate using solid source molecular beam epitaxy. Their growth and behavior on both vicinal and non-vicinal GaAs (111) substrates were investigated by reflection high-energy electron diffraction, atomic force microscopy, x-ray diffraction, and high resolution transmission electron microscopy. It is found that non-vicinal GaAs (111) substrate is better than a vicinal substrate to provide high quality Bi2Te3 and Sb2Te3 films. Hall and magnetoresistance measurements indicate that p type Sb2Te3 and n type Bi2Te3 topological insulator films can be directly grown on a GaAs (111) substrate, which may pave a way to fabricate topological insulator p-n junction on the same substrate, compatible with the fabrication process of present semiconductor optoelectronic devices.

Zhaoquan Zeng; Timothy A. Morgan; Dongsheng Fan; Chen Li; Yusuke Hirono; Xian Hu; Yanfei Zhao; Joon Sue Lee; Zhiming M. Wang; Jian Wang; Shuiqing Yu; Michael E. Hawkridge; Mourad Benamara; Gregory J. Salamo

2013-01-03T23:59:59.000Z

197

Optical anisotropy of GaSb type-II nanorods on vicinal (111)B GaAs  

SciTech Connect

We form self-assembled GaSb type-II nanorods on a vicinal (111)B GaAs substrate by molecular beam epitaxy and study their optical anisotropy. The GaSb nanorods are elongated and aligned along the [-1 0 1] direction, where the average length, width, and height are about 84, 30, and 2.5 nm. In polarized photoluminescence (PL) measurements, the peak of the GaSb nanorods is observed at about 1.1 eV, where the PL intensity is largest for the [-1 0 1] polarization and smallest for the polarization perpendicular to it. The degree of polarization is more than 20% and depends on the recombination energy. By comparing with a theoretical model based on 4 x 4 Luttinger-Kohn Hamiltonian, we find that the experimental results are explained by considering the Sb/As inter-diffusion and the nanorod height distribution.

Kawazu, Takuya; Noda, Takeshi; Mano, Takaaki; Sakuma, Yoshiki [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Akiyama, Yoshihiro [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya (Japan); Sakaki, Hiroyuki [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya (Japan)

2011-12-05T23:59:59.000Z

198

Quaternary Bismide Alloy ByGa1-yAs1-xBix Lattice Matched to GaAs  

DOE Green Energy (OSTI)

We report on the lattice matched quaternary alloy, B{sub y}Ga{sub 1-y}As{sub 1-x}Bi{sub x} grown by molecular beam epitaxy at conditions conducive to bismuth incorporation. Incorporating a smaller atom (boron) along with the larger atom (bismuth) allows for a reduction of the epi-layer strain and lattice matching to GaAs for compositions of Bi:B{approx_equal}1.3:1. The addition of boron flux does not significantly affect the bismuth incorporation and no change in the band gap energy is observed with increasing boron content. However, excess, non-substitutional boron is incorporated which leads to an increase in hole density, as well as an increase in the density of shallow in-gap states as observed by the loss of localization of photo-excited excitons.

Deaton, D. A.; Ptak, A. J.; Alberi, K.; Mascarenhas, A.

2012-07-15T23:59:59.000Z

199

Effects of laser irradiation on the self-assembly of MnAs nanoparticles in a GaAs matrix  

SciTech Connect

We investigate the effects of laser irradiation on the self-assembly of MnAs nanoparticles during solid-phase decomposition in a GaAs matrix. It is found that laser irradiation suppresses the growth of MnAs nanoparticles from small to large size, and that the median diameter D{sub 1} in the size distribution of small MnAs nanoparticles depends on the incident photon energy E following D{sub 1} {approx} E{sup -1/5}. We explain this behavior by the desorption of Mn atoms on the MnAs nanoparticle surface due to resonant optical absorption, in which incident photons excite intersubband electronic transitions between the quantized energy levels in the MnAs nanoparticles.

Hai, Pham Nam; Nomura, Wataru [Department of Electrical Engineering and Information Systems, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Yatsui, Takashi; Ohtsu, Motoichi; Tanaka, Masaaki [Department of Electrical Engineering and Information Systems, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nanophotonics Research Center, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2012-11-05T23:59:59.000Z

200

Structural and magnetic properties of MnAs nanoclusters formed by Mn ion implantation in GaAs  

SciTech Connect

Ferromagnetic (FM) nanostructures embedded in semiconductors are of fundamental interest since their physical properties could be used in new devices such as memories, sensors or spintronics. In this work, we present results obtained on the synthesis and characterization of nanosized MnAs ferromagnets buried in GaAs. These nanocrystals are formed either by single Mn implantation or Mn + As co-implantation at room temperature into GaAs wafers at 141 and 180 keV respectively. Two doses, 1 x 10{sup 16} and 2 x 10{sup 16} ions {center_dot} cm{sup -2} for each impurity, are tested. Pieces of the wafers are then annealed by RTA or classical furnace annealing at various temperatures under N{sub 2} atmosphere for increasing times. HRTEM and diffraction analysis show that under such conditions MnAs precipitates form with a regular hexagonal structure, the 3m orientation-relationship of precipitates with respect to the matrix offers the most energetically stable configuration. Size distributions are systematically extracted from statistical analysis of ''2 beam'' TEM images. The precipitate mean diameters of nanocrystals populations range from 9 to 13 nm depending on the annealing conditions. Magnetization measurements by SQUID magnetometry on the same samples reveal a progressive transition from a superparamagnetic behavior at room temperature to an FM one at 2K, reflecting a distribution of blocking temperature, due to distribution of size and to dipolar interactions. Curie temperatures in the range of 360K were measured.

Serres, A.; Benassayag, G.; Respaud, M.; Armand, C.; Pesant, J.C.; Mari, A.; Liliental-Weber, Z.; Claverie, A.

2002-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Electrically active Er doping in InAs, In{sub 0.53}Ga{sub 0.47}As, and GaAs  

SciTech Connect

The electron concentration in dilute alloys of Er in GaAs, In{sub 0.53}Ga{sub 0.47}As, and InAs grown by molecular beam epitaxy is studied as a function of Er concentration and In content. Using first-principles calculations based on hybrid density functional theory, we attribute an observed increase in conduction electron concentration to Er incorporation on interstitial sites. Er also incorporates on substitutional sites where it is isovalent and electrically inactive. The formation energy of interstitial Er in InAs is significantly smaller than in GaAs, allowing for more electrically active Er in InAs. The results provide insight into characteristics of rare-earth elements as dopants in semiconductors.

Burke, Peter G.; Ismer, Lars; Lu Hong; Frantz, Elan; Janotti, Anderson; Van de Walle, Chris G.; Bowers, John E.; Gossard, Arthur C. [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States)

2012-12-03T23:59:59.000Z

202

Preliminary materials assessment for the Satellite Power System (SPS)  

DOE Green Energy (OSTI)

Presently, there are two SPS reference design concepts (one using silicon solar cells; the other using gallium arsenide solar cells). A materials assessment of both systems was performed based on the materials lists set forth in the DOE/NASA SPS Reference System Report: Concept Development and Evaluation Program. This listing identified 22 materials (plus miscellaneous and organics) used in the SPS. Tracing the production processes for these 22 materials, a total demand for over 20 different bulk materials (copper, silicon, sulfuric acid, etc.) and nealy 30 raw materials (copper ore, sand, sulfur ore, etc.) was revealed. Assessment of these SPS material requirements produced a number of potential material supply problems. The more serious problems are those associated with the solar cell materials (gallium, gallium arsenide, sapphire, and solar grade silicon), and the graphite fiber required for the satellite structure and space construction facilities. In general, the gallium arsenide SPS option exhibits more serious problems than the silicon option, possibly because gallium arsenide technology is not as well developed as that for silicon. Results are presented and discussed in detail. (WHK)

Teeter, R.R.; Jamieson, W.M.

1980-01-01T23:59:59.000Z

203

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) 254. [9] J. Tersoff, M.D. Johnson, B.G. Orr, Phys. Rev. Lett. 78 (1997) 282. [10] V.P. LaBella, D.W.M. Thibado, G.J. Salamo, Y. Baharav, J. Vac. Sci. Technol. B 17 (1999) 253. [12] J.B. Smathers, D.W. Bullock

Thibado, Paul M.

204

Ion exchange separation of plutonium and gallium (1) resource and inventory requirements, (2) waste, emissions, and effluent, and (3) facility size  

SciTech Connect

The following report summarizes an effort intended to estimate within an order-of-magnitude the (1) resource and inventory requirements, (2) waste, emissions, and effluent amounts, and (3) facility size, for ion exchange (IX) separation of plutonium and gallium. This analysis is based upon processing 3.5 MT-Pu/yr. The technical basis for this summary is detailed in a separate document, {open_quotes}Preconceptual Design for Separation of Plutonium and Gallium by Ion Exchange{close_quotes}. The material balances of this separate document are based strictly on stoichiometric amounts rather than details of actual operating experience, in order to avoid classification as Unclassified Controlled Nuclear Information. This approximation neglets the thermodynamics and kinetics which can significantly impact the amount of reagents required. Consequently, the material resource requirements and waste amounts presented here would normally be considered minimums for processing 3.5 MT-Pu/yr; however, the author has compared the inventory estimates presented with that of an actual operating facility and found them similar. Additionally, the facility floor space presented here is based upon actual plutonium processing systems and can be considered a nominal estimate.

DeMuth, S.

1997-09-30T23:59:59.000Z

205

Highest transmittance and high-mobility amorphous indium gallium zinc oxide films on flexible substrate by room-temperature deposition and post-deposition anneals  

Science Conference Proceedings (OSTI)

Amorphous indium gallium zinc oxide (a-IGZO) thin films of the highest transmittance reported in literature were initially deposited onto flexible polymer substrates at room temperature. The films were annealed in vacuum, air, and oxygen to enhance their electrical and optical performances. Electrical and optical characterizations were done before and after anneals. A partial reversal of the degradation in electrical properties upon annealing in oxygen was achieved by subjecting the films to subsequent vacuum anneals. A model was developed based on film texture and structural defects which showed close agreement between the measured and calculated carrier mobility values at low carrier concentrations (2-6 x 10{sup 19} cm{sup -3}).

Gadre, Mandar J. [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Alford, T. L. [School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Flexible Display Center at Arizona State University, Tempe, Arizona 85284 (United States)

2011-08-01T23:59:59.000Z

206

Three Alkali-Metal-Gold-Gallium Systems. Ternary Tunnel Structures and Some Problems with Poorly Ordered Cations  

SciTech Connect

Six new intermetallic compounds have been characterized in the alkali metal (A = Na, Rb, Cs)–gold–gallium systems. Three isostructural compounds with the general composition A0.55Au2Ga2, two others of AAu3Ga2 (A = Rb, Cs), and the related Na13Au41.2Ga30.3 were synthesized via typical high-temperature reactions and their crystal structures determined by single-crystal X-ray diffraction analysis: Na0.56(9)Au2Ga2 (I, I4/mcm, a = 8.718(1) Å, c = 4.857(1) Å, Z = 4), Rb0.56(1)Au2Ga2 (II, I4/mcm, a = 8.950(1) Å, c = 4.829(1) Å, Z = 4), Cs0.54(2)Au2Ga2 (III, I4/mcm, a = 9.077(1) Å, c = 4.815(1) Å, Z = 4), RbAu3Ga2 (IV, Pnma, a = 13.384(3) Å, b = 5.577(1) Å, c = 7.017(1) Å, Z = 4), CsAu3Ga2 (V, Pnma, a = 13.511(3) Å, b = 5.614(2) Å, c = 7.146(1) Å, Z = 4), Na13Au41.2(1)Ga30.3(1) (VI, P6 mmm, a = 19.550(3) Å, c = 8.990(2) Å, Z = 2). The first three compounds (I–III) are isostructural with tetragonal K0.55Au2Ga2 and likewise contain planar eight-member Au/Ga rings that stack along c to generate tunnels and that contain varying degrees of disordered Na–Cs cations. The cation dispositions are much more clearly and reasonably defined by electron density mapping than through least-squares refinements with conventional anisotropic ellipsoids. Orthorhombic AAu3Ga2 (IV, V) are ordered ternary Rb and Cs derivatives of the SrZn5 type structure, demonstrating structural variability within the AAu3Ga2 family. All attempts to prepare an isotypic “NaAu3Ga2” were not successful, but yielded only a similar composition Na13Au41.2Ga30.3 (NaAu3.17Ga2.33) (VI) in a very different structure with two types of cation sites. Crystal orbital Hamilton population (COHP) analysis obtained from tight-binding electronic structure calculations for idealized I–IV via linear muffin-tin-orbital (LMTO) methods emphasized the major contributions of heteroatomic Au–Ga bonding to the structural stability of these compounds. The relative minima (pseudogaps) in the DOS curves for IV correspond well with the valence electron counts of known representatives of this structure type and, thereby, reveal some magic numbers to guide the search for new isotypic compounds. Theoretical calculation of total energies vs volumes obtained by VASP (Vienna Ab initio Simulation Package) calculations for KAu3Ga2 and RbAu3Ga2 suggest a possible transformation from SrZn5- to BaZn5-types at high pressure.

Smetana, Volodymyr; Miller, Gordon J.; Corbett, John D.

2012-06-27T23:59:59.000Z

207

Final Technical Progress Report: High-Efficiency Low-Cost Thin-Film GaAs Photovoltaic Module Development Program; July 14, 2010 - January 13, 2012  

DOE Green Energy (OSTI)

This is the final technical progress report of the High-Efficiency Low-Cost Thin-Film GaAs Photovoltaic Module Development Program. Alta Devices has successfully completed all milestones and deliverables established as part of the NREL PV incubator program. During the 18 months of this program, Alta has proven all key processes required to commercialize its solar module product. The incubator focus was on back end process steps directed at conversion of Alta's high quality solar film into high efficiency 1-sun PV modules. This report describes all program deliverables and the work behind each accomplishment.

Mattos, L.

2012-03-01T23:59:59.000Z

208

2 {mu}m laterally coupled distributed-feedback GaSb-based metamorphic laser grown on a GaAs substrate  

SciTech Connect

We report a type-I GaSb-based laterally coupled distributed-feedback (DFB) laser grown on a GaAs substrate operating continuous wave at room temperature. The laser structure was designed to operate near a wavelength of 2 {mu}m and was grown metamorphically with solid-source molecular beam epitaxy. The device was fabricated using a 6th-order deep etch grating structure as part of the sidewalls of the narrow ridge waveguide. The DFB laser emits total output power of up to 40 mW in a single longitudinal mode operation at a heat-sink temperature of 20 Degree-Sign C.

Apiratikul, P.; He, L.; Richardson, C. J. K. [Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740 (United States)] [Laboratory for Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740 (United States)

2013-06-10T23:59:59.000Z

209

InGaAsN Solar Cells with 1.0eV Bandgap, Lattice Matched to GaAs  

DOE Green Energy (OSTI)

The design, growth by metal-organic chemical vapor deposition, and processing of an In{sub 0.07}Ga{sub 0.93}As{sub 0.98}N{sub 0.02} solar Al, with 1.0 ev bandgap, lattice matched to GaAs is described. The hole diffusion length in annealed, n-type InGaAsN is 0.6-0.8 pm, and solar cell internal quantum efficiencies > 70% arc obwined. Optical studies indicate that defects or impurities, from InGAsN doping and nitrogen incorporation, limit solar cell performance.

Allerman, A.A.; Banas, J.J.; Gee, J.M.; Hammons, B.E.; Jones, E.D.; Kurtz, S.R.

1998-11-24T23:59:59.000Z

210

An Ultra High Speed Test System  

Science Conference Proceedings (OSTI)

The test-head subsystem presented uses gallium arsenide pin electronics to provide nonrepeating zero data rates up to 1.2 Gb/s. The device under test is connected to laser-scanned optical sensors, and the test system receivers use an electrooptic measurement ...

Francois Henley

1989-01-01T23:59:59.000Z

211

SOLERAS - University Research Project. Progress report No. 3, 1984-85 annual report  

Science Conference Proceedings (OSTI)

The accomplishments of solar energy research projects maintained by nine US universities are summarized. Some research topics covered include: photosynthesis; passive cooling; crystal growth of gallium arsenides; concentrating optics for PV conversion; amorphous silicon alloys; solar insolation; solar ponds; and wind power. (BCS)

Not Available

1985-09-01T23:59:59.000Z

212

SOLERAS - University Research Project. Progress report 1, December 1984  

Science Conference Proceedings (OSTI)

Progress to date on each of the research efforts in direct solar energy applications at public and private institutions of higher education and research in the United States is addressed. Some research topics covered include: concentrating optics for PV conversion; wind power; solar ponds; photosynthesis; amorphous silicon alloys; passive cooling; crystal growth of gallium arsenides; and solar insolation.

Not Available

1984-12-01T23:59:59.000Z

213

Growth and Properties of the Dilute Bismide Semiconductor GaAs1-xBix a Complementary Alloy to the Dilute Nitrides  

DOE Green Energy (OSTI)

In this review we describe the growth and properties of the dilute bismide semiconductor alloy GaAs{sub 1-x}Bi{sub x} and show how its properties are in certain respects complementary to the dilute nitride alloy, GaN{sub y}As{sub 1-y}. Like the dilute nitrides the dilute bismides show a giant band gap bowing effect in which a small concentration of the alloying element has a disproportionate effect on the band gap, however in the case of the bismide the band gap reduction is associated with an increase in the energy of the valence band maximum (VBM) rather than a reduction in the energy of the conduction band minimum (CBM). Under standard GaAs growth conditions Bi acts as a surfactant with associated improvements in surface quality. In order to incorporate Bi, growth temperatures below 400 C are used with As{sub 2}/Ga flux ratios close to unity. The electron mobility of GaAs is only weakly affected by Bi alloying, in contrast to the dilute nitrides where the electron mobility decreases rapidly with N alloying. Bi alloying also produces a giant bowing effect in the spin orbit splitting in the valence band. Strong room temperature photoluminescence is observed. Prospects for future device applications of this new compound semiconductor alloy are discussed.

Tiedje, T.; Young, E. C.; Mascarenhas, A.

2008-01-01T23:59:59.000Z

214

On-Sun Comparison of GaInP2/GaAs Tandem Cells with Top-Cell Thickness Varied  

DOE Green Energy (OSTI)

This study compares the on-sun performance of a set of GaInP2/GaAs tandem cells with different GaInP2 top-cell thicknesses. Because high-efficiency III-V cells are best suited to concentrating photovoltaic (CPV) applications, the cells were mounted on a two-axis tracker with the incident sunlight collimated to exclude all except the direct beam. Current-voltage (I-V) curves were taken throughout the course of several days, along with the direct solar spectrum. Our two major conclusions are: (1) GaInP2/GaAs tandem cells designed for an ''air mass 1.5 global'' (AM 1.5G) or a ''low aerosol optical depth'' (Low AOD) spectrum perform the best, and (2) a simple device model using the measured direct spectra as an input gives the same result. These results are equally valid for GaInP2/GaAs/Ge triple-junction cells.

McMahon, W. E.; Emery, K. A.; Friedman, D. J.; Ottoson, L.; Young, M. S.; Ward, J. S.; Kramer, C. M.; Duda, A.; Kurtz, S.

2005-01-01T23:59:59.000Z

215

The effect of encapsulation on the morphology and chemical composition of InAs/GaAs quantum dots grown by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

In order to fabricate an effective device structure based on InAs quantum dots (QDs), the QD layers must be encapsulated within a matrix that has a wider band gap. This encapsulation is usually achieved by the overgrowth of GaAs. Coherent strained InAs/GaAs ... Keywords: encapsulation, indium arsenide, quantum dots, transmission electron microscopy

D. Zhi; M. Wei; R. E. Dunin-Borkowski; P. A. Midgley; D. W. Pashley; T. S. Jones; B. A. Joyce; P. F. Fewster; P. J. Goodhew

2004-06-01T23:59:59.000Z

216

Electron mobility and effective mass in composite InGaAs quantum wells with InAs and GaAs nanoinserts  

Science Conference Proceedings (OSTI)

The paper is concerned with the theoretical and experimental studies of the band structure and electrical properties of InAlAs/InGaAs/InAlAs/InP heterostructures containing a composite InGaAs quantum well with InAs and GaAs nanoinserts. From the Shubnikov-de Haas effect, the effective cyclotron mass m{sub c}* is determined experimentally and calculated with consideration for the nonparabolicity of the electron energy spectrum. An approach to estimation of the effective mass is proposed and tested. The approach is based on weighted averaging of the m{sub c}* of the composite quantum well's constituent materials. A first proposed heterostructure containing two InAs inserts symmetrically arranged in the quantum well makes a 26% reduction in m{sub c}* compared to m{sub c}* in the lattice-matched In{sub 0.53}Ga{sub 0.47}As quantum well possible.

Ponomarev, D. S., E-mail: ponomarev_dmitr@mail.ru; Vasil'evskii, I. S. [National Nuclear Research University 'Moscow Engineering Physics Institute (MEPhI)' (Russian Federation); Galiev, G. B.; Klimov, E. A. [Russian Academy of Sciences, Institute of Ultrahigh-Frequency Semiconductor Electronics (Russian Federation); Khabibullin, R. A. [National Nuclear Research University 'Moscow Engineering Physics Institute (MEPhI)' (Russian Federation); Kulbachinskii, V. A.; Uzeeva, N. A. [Moscow State University (Russian Federation)

2012-04-15T23:59:59.000Z

217

Crystal field disorder effects in the optical spectra of Nd{sup 3+} and Yb{sup 3+}-doped calcium lithium niobium gallium garnets laser crystals and ceramics  

SciTech Connect

The optical spectroscopic properties of RE{sup 3+} (Nd, 1 at. % or Yb, 1 to 10 at. %)-doped calcium-lithium-niobium-gallium garnet (CLNGG) single crystals and ceramics in the 10 K-300 K range are analyzed. In these compositionally disordered materials, RE{sup 3+} substitute Ca{sup 2+} in dodecahedral sites and the charge compensation is accomplished by adjusting the proportion of Li{sup +}, Nb{sup 5+}, and Ga{sup 3+} to the doping concentration. The crystals and ceramics show similar optical spectra, with broad and structured (especially at low temperatures) bands whose shape depends on temperature and doping concentration. At 10 K, the Nd{sup 3+4}I{sub 9/2}{yields}{sup 4}F{sub 3/2,5/2} and Yb{sup 3+2}F{sub 7/2}{yields}{sup 2}F{sub 5/2} absorption bands, which show prospect for diode laser pumping, can be decomposed in several lines that can be attributed to centers with large differences in the crystal field. The positions of these components are the same, but the relative intensity depends on the doping concentration and two main centers dominate the spectra. Non-selective excitation evidences broad emission bands, of prospect for short-pulse laser emission, whereas the selective excitation reveals the particular emission spectra of the various centers. The modeling reveals that the nonequivalent centers correspond to RE{sup 3+} ions with different cationic combinations in the nearest octahedral and tetrahedral coordination spheres, and the most abundant two centers have 4Nb and, respectively, 3Nb1Li in the nearest octahedral sphere. At 300 K, the spectral resolution is lost. It is then inferred that the observed optical bands are envelopes of the spectra of various structural centers, whose resolution is determined by the relative contribution of the temperature-dependent homogeneous broadening and the effects of crystal field disordering (multicenter structure, inhomogeneous broadening). The relevance of spectroscopic properties for selection of pumping conditions and of laser design that would enable utilization of the broad optical bands for efficient laser emission and reduced heat generation is discussed.

Lupei, V.; Lupei, A.; Gheorghe, C.; Gheorghe, L.; Achim, A. [National Institute for Lasers, Plasma and Radiation Physics, Lab. ECS, Bucharest (Romania); Ikesue, A. [World-Lab Co. Ltd., Atsuta-ku, Nagoya 456-8587 (Japan)

2012-09-15T23:59:59.000Z

218

Measurement of the solar neutrino capture rate with gallium metal. III: Results for the 2002--2007 data-taking period  

E-Print Network (OSTI)

The Russian-American experiment SAGE began to measure the solar neutrino capture rate with a target of gallium metal in Dec. 1989. Measurements have continued with only a few brief interruptions since that time. We give here the experimental improvements in SAGE since its last published data summary in Dec. 2001. Assuming the solar neutrino production rate was constant during the period of data collection, combined analysis of 168 extractions through Dec. 2007 gives a capture rate of solar neutrinos with energy more than 233 keV of 65.4 (+3.1)(-3.0) (stat) (+2.6)(-2.8) (syst) SNU. The weighted average of the results of all three Ga solar neutrino experiments, SAGE, Gallex, and GNO, is now 66.1 +/- 3.1 SNU, where statistical and systematic uncertainties have been combined in quadrature. During the recent period of data collection a new test of SAGE was made with a reactor-produced 37Ar neutrino source. The ratio of observed to calculated rates in this experiment, combined with the measured rates in the three prior 51Cr neutrino-source experiments with Ga, is 0.87 +/- 0.05. A probable explanation for this low result is that the cross section for neutrino capture by the two lowest-lying excited states in 71Ge has been overestimated. If we assume these cross sections are zero, then the standard solar model including neutrino oscillations predicts a total capture rate in Ga in the range of 63-66 SNU with an uncertainty of about 4%, in good agreement with experiment. We derive the current value of the neutrino flux produced in the Sun by the proton-proton fusion reaction to be (6.0 +/- 0.8) x 10^(10)/(cm^2 s), which agrees well with the pp flux predicted by the standard solar model. Finally, we show that the data are consistent with the assumption that the solar neutrino production rate is constant in time.

SAGE Collaboration; J. N. Abdurashitov; V. N. Gavrin; V. V. Gorbachev; P. P. Gurkina; T. V. Ibragimova; A. V. Kalikhov; N. G. Khairnasov; T. V. Knodel; I. N. Mirmov; A. A. Shikhin; E. P. Veretenkin; V. E. Yants; G. T. Zatsepin; T. J. Bowles; S. R. Elliott; W. A. Teasdale; J. S. Nico; B. T. Cleveland; J. F. Wilkerson

2009-01-15T23:59:59.000Z

219

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

220

Development of electrochemical photovoltaic cells. Third technical progress report, November 1, 1979-January 31, 1980  

DOE Green Energy (OSTI)

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

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

World Supply and Demand  

Science Conference Proceedings (OSTI)

Table 4   Gallium arsenide ingot, wafer, and device manufacturers...X Sweden Semitronics AB X United Kingdom General Electricity Company (U.K.) X X X X X MCP Electronic Materials Ltd. X United States Airtron Division of Litton Industries X Anadigics Inc. X X X Applied Solar Energy Corporation X X AT & T Bell Laboratories X X X X Bertram Laboratories X Crystal Specialties,...

222

SOLERAS - University Research Project. Progress report 2  

Science Conference Proceedings (OSTI)

Progress to date on each of the research efforts in direct solar energy applications at public and private institutions of higher education and research in the United States is addressed. Some research topics covered include: concentrating optics for PV conversion; wind power; solar ponds; photosynthesis; amorphous silicon alloys; passive cooling; crystal growth of gallium arsenides; and solar insolation. The period of work covered by these reports is June 1984 through February 1985.

Not Available

1985-03-01T23:59:59.000Z

223

Ga-Zr (Gallium - Zirconium)  

Science Conference Proceedings (OSTI)

Ga-Zr crystallographic data...Ga 5 Zr 3 44.0 oC 32 Cmcm Ga 3 Zr 2 47 oF 40 Fdd 2 βGaZr 56.7 � � αGaZr 56.7 tI 16 I 4 1 / amd Ga 4 Zr 5 62.1 hP 18 P 6 3 / mcm Ga 2 Zr 3 66 tP 10 P 4/ mbm Ga 3 Zr 5 68.6 hP 16 P 6 3 / mcm GaZr 2 72.4 tI 12 I 4/ mcm (βZr) ~94 to 100 cI 2 Im m (αZr) 99.4 to 100 hP 2 P 6 3 / mmc...

224

Ba-Ga (Barium - Gallium)  

Science Conference Proceedings (OSTI)

Ba-Ga crystallographic data...Ba-Ga crystallographic data Phase Composition, wt% Ga Pearson symbol Space group (Ba) 0 cI 2 Im m Ba 10 Ga 4.8 cF 176 Fd m Ba 8 Ga 7 30.8 cP 60 P 2 1 3 BaGa 2 50.4 hP 3 P 6/ mmm BaGa 4 67 tI 10 I 4/ mmm (Ga) 100 hP 2 P 6 3 / mmc...

225

Gallium interactions with zircaloy cladding  

Science Conference Proceedings (OSTI)

The effects of Ga from weapons-grade plutonium MOX fuel on zircaloy-IV cladding during power reactor operation have been simulated by implantations of 100 keV Ga-69 ions into a polished zircaloy-IV sample while the sample was maintained at a typical cladding temperature of 375{degrees}C. Analyses were based on scanning electron microscopy, Rutherford backscattering of 280 keV He-3 ions, and secondary ion mass spectroscopy. Subgrains at the zircaloy-IV surface formed at a Ga fluence equivalent to total release of approximately 12 ppm by weight of Ga from the fuel. The subgrains may be an intermetallic compound of Zr{sub 2}Ga. Enhanced diffusion of Ga was observed, but Ga concentrations decreased 3 orders of magnitude over a depth of 3000 {angstrom}.

Hart, R.R.; Rennie, J.; Aucoin, K.; West, M. [Texas A& M Univ., College Station, TX (United States)

1998-05-01T23:59:59.000Z

226

Determination of bandgap states in p-type In[subscript 0.49]Ga[subscript 0.51]P grown on SiGe/Si and GaAs by deep level optical spectroscopy and deep level transient spectroscopy  

E-Print Network (OSTI)

The presence and properties of traps in p-type In[subscript 0.49]Ga[subscript 0.51]P grown on low dislocation density, metamorphic Ge/SiGe/Si substrates and GaAs substrates were determined using deep level transient ...

Gonza?lez, M.

227

Boron arsenide thin film solar cell development. Final report  

DOE Green Energy (OSTI)

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

228

R6, Low Field Electron Transport in Mixed Arsenide Antimonide ...  

Science Conference Proceedings (OSTI)

Mixed anion InAsySb1-y quantum wells (QW) with high electron mobility are excellent candidates for direct integration with high hole ...

229

Molecular beam epitaxial growth of metamorphic AlInSb/GaInSb high-electron-mobility-transistor structures on GaAs substrates for low power and high frequency applications  

Science Conference Proceedings (OSTI)

We report on molecular beam epitaxial growth of AlInSb/GaInSb metamorphic high-electron-mobility-transistor structures for low power, high frequency applications on 4 in. GaAs substrates. The structures consist of a Ga{sub 0.4}In{sub 0.6}Sb channel embedded in Al{sub 0.4}In{sub 0.6}Sb barrier layers which are grown on top of an insulating metamorphic buffer, which is based on the linear exchange of Ga versus In and a subsequent exchange of As versus Sb. Precise control of group V fluxes and substrate temperature in the Al{sub 0.4}In{sub 0.6}As{sub 1-x}Sb{sub x} buffer is essential to achieve high quality device structures. Good morphological properties were achieved demonstrated by the appearance of crosshatching and root mean square roughness values of 2.0 nm. Buffer isolation is found to be >100 k{Omega}/{open_square} for optimized growth conditions. Hall measurements at room temperature reveal electron densities of 2.8x10{sup 12} cm{sup -2} in the channel at mobility values of 21.000 cm{sup 2}/V s for single-sided Te volume doping and 5.4x10{sup 12} cm{sup -2} and 17.000 cm{sup 2}/V s for double-sided Te {delta}-doping, respectively.

Loesch, R.; Aidam, R.; Kirste, L.; Leuther, A. [Fraunhofer Institute for Applied Solid-State Physics (IAF), Tullastrasse 72, 79108 Freiburg (Germany)

2011-02-01T23:59:59.000Z

230

Gallium composition dependence of crystallographic and thermoelectric properties in polycrystalline type-I Ba{sub 8}Ga{sub x}Si{sub 46-x} (nominal x=14-18) clathrates prepared by combining arc melting and spark plasma sintering methods  

SciTech Connect

The gallium composition dependence of crystallographic and thermoelectric properties in polycrystalline n-type Ba{sub 8}Ga{sub x}Si{sub 46-x} (nominal x=14-18) compounds with the type-I clathrate structure is presented. Samples were prepared by combining arc melting and spark plasma sintering methods. Powder x-ray diffraction, Rietveld analysis, scanning electron microscopy, and energy-dispersive x-ray spectroscopy show that the solubility limit of gallium in the type-I clathrate phase is close to x=15, which is slightly higher than that for a single crystal. The carrier concentration at room temperature decreases from 2 Multiplication-Sign 10{sup 21} cm{sup -3} to 4 Multiplication-Sign 10{sup 20} cm{sup -3} as the Ga content x increases. The Seebeck coefficient, the electrical conductivity, and the thermal conductivity vary systematically with the carrier concentration when the Ga content x varies. The effective mass (2.0m{sub 0}), the carrier mobility (10 cm{sup 2} V{sup -1} s{sup -1}), and the lattice thermal conductivity (1.1 W m{sup -1} K{sup -1}) are determined for the Ga content x=14.51. The dimensionless thermoelectric figure of merit ZT is about 0.55 at 900 K for the Ga content x=14.51. The calculation of ZT using the experimentally determined material parameters predicts ZT=0.8 (900 K) at the optimum carrier concentration of about 2 Multiplication-Sign 10{sup 20} cm{sup -3}. - Graphical abstract: The gallium composition dependence of crystallographic and thermoelectric properties is presented on polycrystalline n-type Ba{sub 8}Ga{sub x}Si{sub 46-x} with the type-I clathrate structure prepared by combining arc melting and spark plasma sintering methods. The thermoelectric figure of merit ZT reaches 0.55 at 900 K due to the increase in the Ga content (close to x=15), and a calculation predicts further improvement of ZT at the optimized carrier concentration. Highlights: Black-Right-Pointing-Pointer Crystallographic properties of Ba{sub 8}Ga{sub x}Si{sub 46-x} clathrates are characterized. Black-Right-Pointing-Pointer Arc melting and spark plasma sintering process enables increase of Ga content. Black-Right-Pointing-Pointer We elucidate the Ga composition dependence of thermoelectric properties. Black-Right-Pointing-Pointer Thermoelectric figure of merit ZT is improved due to the increased Ga content. Black-Right-Pointing-Pointer Calculation predicts a potential ZT=0.8 at 900 K at optimized carrier concentration.

Anno, Hiroaki, E-mail: anno@rs.tus.ac.jp [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyoonoda 756-0884 (Japan) [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyoonoda 756-0884 (Japan); JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan); Yamada, Hiroki; Nakabayashi, Takahiro; Hokazono, Masahiro [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyoonoda 756-0884 (Japan)] [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyoonoda 756-0884 (Japan); Shirataki, Ritsuko [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyoonoda 756-0884 (Japan) [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science, Yamaguchi, 1-1-1 Daigaku-Dori, Sanyoonoda 756-0884 (Japan); JST, CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan)

2012-09-15T23:59:59.000Z

231

Plating on difficult-to-plate metals: what's new  

SciTech Connect

Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required.

Wiesner, H.J.

1980-07-30T23:59:59.000Z

232

Quantum interference and control of the dynamic Franz-Keldysh effect: Generation and detection of terahertz space-charge fields  

Science Conference Proceedings (OSTI)

The Dynamic Franz Keldysh Effect (DFKE) is produced and controlled in bulk gallium arsenide by quantum interference without the aid of externally applied fields and is spatially and temporally resolved using ellipsometric pump-probe techniques. The {approx}3 THz internal driving field for the DFKE is a transient space-charge field that is associated with a critically damped coherent plasma oscillation produced by oppositely traveling ballistic electron and hole currents that are injected by two-color quantum interference techniques. The relative phase and polarization of the two pump pulses can be used to control the DFKE.

Wang, Rui [Laboratory for Photonics and Quantum Electronics, 138 IATL, University of Iowa, Iowa City, Iowa 52242 (United States) [Laboratory for Photonics and Quantum Electronics, 138 IATL, University of Iowa, Iowa City, Iowa 52242 (United States); Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States); Jacobs, Paul; Smirl, Arthur L. [Laboratory for Photonics and Quantum Electronics, 138 IATL, University of Iowa, Iowa City, Iowa 52242 (United States)] [Laboratory for Photonics and Quantum Electronics, 138 IATL, University of Iowa, Iowa City, Iowa 52242 (United States); Zhao, Hui [Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States)] [Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States)

2013-06-24T23:59:59.000Z

233

Nanobeam Photonic Crystal Cavity Light-Emitting Diodes  

E-Print Network (OSTI)

We present results on electrically driven nanobeam photonic crystal cavities formed out of a lateral p-i-n junction in gallium arsenide. Despite their small conducting dimensions, nanobeams have robust electrical properties with high current densities possible at low drive powers. Much like their two-dimensional counterparts, the nanobeam cavities exhibit bright electroluminescence at room temperature from embedded 1,250 nm InAs quantum dots. A small room temperature differential gain is observed in the cavities with minor beam self-heating suggesting that lasing is possible. These results open the door for efficient electrical control of active nanobeam cavities for diverse nanophotonic applications.

Shambat, Gary; Petykiewicz, Jan; Mayer, Marie A; Sarmiento, Tomas; Harris, James; Haller, Eugene E; Vuckovic, Jelena

2011-01-01T23:59:59.000Z

234

The state of the art of thin-film photovoltaics  

DOE Green Energy (OSTI)

Thin-film photovoltaic technologies, based on materials such as amorphous or polycrystalline silicon, copper indium diselenide, cadmium telluride, and gallium arsenide, offer the potential for significantly reducing the cost of electricity generated by photovoltaics. The significant progress in the technologies, from the laboratory to the marketplace, is reviewed. The common concerns and questions raised about thin films are addressed. Based on the progress to date and the potential of these technologies, along with continuing investments by the private sector to commercialize the technologies, one can conclude that thin-film PV will provide a competitive alternative for large-scale power generation in the future.

Surek, T.

1993-10-01T23:59:59.000Z

235

References and Notes for Gallium ( Ga )  

Science Conference Proceedings (OSTI)

... Res. Natl. Bur. Stand. (US) 48, 334 (1952). ND82, JHM Neijzen and A. Donszelmann, Physica 114C, 241 (1982). The stated ...

236

Controlling Gallium Nitride Polarity on Native Substrates  

Science Conference Proceedings (OSTI)

Symposium, Advanced Materials for Power Electronics, Power Conditioning, and Power Conversion ... Potential Ceramic Dielectrics for Air Force Applications.

237

Electronic properties of gallium nitride nanowires  

E-Print Network (OSTI)

This thesis presents a systematic study of the electrical transport in GaN nanowires. Particularly, the effect of the surrounding dielectric on the conductivity of GaN nanowires is experimentally shown for the first time. ...

Yoon, Joonah

2008-01-01T23:59:59.000Z

238

Development of gallium nitride power transistors  

E-Print Network (OSTI)

GaN-based high-voltage transistors have outstanding properties for the development of ultra-high efficiency and compact power electronics. This thesis describes a new process technology for the fabrication of GaN power ...

Piedra, Daniel, M. Eng. Massachusetts Institute of Technology

2011-01-01T23:59:59.000Z

239

NREL: News - NREL Reports 31.1% Efficiency for III-V Solar Cell  

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

913 913 NREL Reports 31.1% Efficiency for III-V Solar Cell Conversion-efficiency mark is a world record for a two-junction solar cell measured under one-sun illumination June 24, 2013 The Energy Department's National Renewable Energy Lab has announced a world record of 31.1% conversion efficiency for a two-junction solar cell under one sun of illumination. NREL Scientist Myles Steiner announced the new record June 19 at the 39th IEEE Photovoltaic Specialists Conference in Tampa, Fla. The previous record of 30.8% efficiency was held by Alta Devices. The tandem cell was made of a gallium indium phosphide cell atop a gallium arsenide cell, has an area of about 0.25 square centimeters and was measured under the AM1.5 global spectrum at 1,000 W/m2. It was grown inverted, similar to the NREL-developed inverted metamorphic multi-junction

240

Electronic structure of BAs and boride III-V alloys  

SciTech Connect

Boron arsenide, the typically ignored member of the Group-III--V arsenide series BAs-AlAs-GaAs-InAs is found to resemble silicon electronically: its {Gamma} conduction-band minimum is p-like ({Gamma}{sub 15}), not s-like ({Gamma}{sub 1c}), it has an X{sub 1c}-like indirect band gap, and its bond charge is distributed almost equally on the two atoms in the unit cell, exhibiting nearly perfect covalency. The reasons for these are tracked down to the anomalously low atomic p orbital energy in the boron and to the unusually strong s--s repulsion in BAs relative to most other Group-III--V compounds. We find unexpected valence-band offsets of BAs with respect to GaAs and AlAs. The valence-band maximum (VBM) of BAs is significantly higher than that of AlAs, despite the much smaller bond length of BAs, and the VBM of GaAs is only slightly higher than in BAs. These effects result from the unusually strong mixing of the cation and anion states at the VBM. For the BAs-GaAs alloys, we find (i) a relatively small ({approx}3.5 eV) and composition-independent band-gap bowing. This means that while addition of small amounts of nitrogen to GaAs lowers the gap, addition of small amounts of boron to GaAs raises the gap; (ii) boron ''semilocalized'' states in the conduction band (similar to those in GaN-GaAs alloys); and (iii) bulk mixing enthalpies that are smaller than in GaN-GaAs alloys. The unique features of boride Group-III--V alloys offer new opportunities in band-gap engineering.

Hart, Gus L. W.; Zunger, Alex

2000-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Electronic structure of BAs and boride III–V alloys  

E-Print Network (OSTI)

Boron arsenide, the typically-ignored member of the III–V arsenide series BAs–AlAs–GaAs– InAs is found to resemble silicon electronically: its ? conduction band minimum is p-like (?15), not s-like (?1c), it has an X1c-like indirect band gap, and its bond charge is distributed almost equally on the two atoms in the unit cell, exhibiting nearly perfect covalency. The reasons for these are tracked down to the anomalously low atomic p orbital energy in the boron and to the unusually strong s–s repulsion in BAs relative to most other III–V compounds. We find unexpected valence band offsets of BAs with respect to GaAs and AlAs. The valence band maximum (VBM) of BAs is significantly higher than that of AlAs, despite the much smaller bond length of BAs, and the VBM of GaAs is only slightly higher than in BAs. These effects result from the unusually strong mixing of the cation and anion states at the VBM. For the BAs–GaAs alloys, we find (i) a relatively small (?3.5 eV) and composition-independent band gap bowing. This means that while addition of small amounts of nitrogen to GaAs lowers the gap, addition of small amounts of boron to GaAs raises the gap (ii) boron “semi-localized” states in the conduction band (similar to those in GaN–GaAs alloys), and (iii) bulk mixing enthalpies which are smaller than in GaN–GaAs alloys. The unique features of boride III–V alloys offer new opportunities in band gap engineering. I.

Gus L. W. Hart; Alex Zunger

2000-01-01T23:59:59.000Z

242

Scanning tunneling optical resonance microscopy applied to indium arsenide quantum dot structures.  

E-Print Network (OSTI)

??The technique of Scanning Tunneling Optical Resonance Microscopy (STORM) has been investigated for use on nanostructures. It has been demonstrated as a viable technique to… (more)

Byrnes, Daniel P.

2008-01-01T23:59:59.000Z

243

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

E-Print Network (OSTI)

5.4.2 Electrical Resistivity . . . . . . . . . . . . . . .3.2 Electrical Resistivity . . . . . . . . . . . . . .3.2.3 CEF E?ects on Electrical Resistivity . . 3.3

Sayles, Todd Allen

2008-01-01T23:59:59.000Z

244

COBRA: Determining Atomic Positions in Thin-Film Structures and Interfaces  

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

COBRA: Determining Atomic Positions in Thin-Film Structures and Interfaces COBRA: Determining Atomic Positions in Thin-Film Structures and Interfaces Coherent Bragg rod analyses (COBRA) experiments using synchrotron x-rays at Argonne's Advanced Photon Source (MHATT-CAT and PNC-CAT beamlines) directly revealed the sub-angstrom atomic interaction of epitaxial films with substrates. Information on how atoms in the adjoining layers of the film and substrate rearrange to mimic each other may lead to improvements in semiconductor manufacturing and the development of novel heterostructure materials, such as multilayer ferroelectrics, magnetic nanostructures and thin film superconductors. COBRA electron density map of a Gd2O3 film on a gallium arsenide substrate. The peaks correspond to folded Gd atomic positions parallel to the plane of the substrate.

245

CX-005363: Categorical Exclusion Determination | Department of Energy  

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

5363: Categorical Exclusion Determination 5363: Categorical Exclusion Determination CX-005363: Categorical Exclusion Determination Solar Junction's 100 Megawatt Manufacturing Line CX(s) Applied: B1.31 Date: 03/04/2011 Location(s): San Jose, California Office(s): Loan Guarantee Program Office The Department of Energy's proposed action is to issue a loan guarantee to Solar Junction to finance a 100 megawatt (MW) solar cell manufacturing line for multifunction photovoltaic solar cells to expand their existing 7 MW Demonstration Facility at 401 Charcot Avenue, San Jose, California 95131. The proposed project will commercialize an entirely new class of high-efficiency solar cells and concentrating photovoltaic components that incorporate high performance junctions formed with a tunable band gap semiconductor material, Gallium Indium Nitride Arsenide.

246

The Story of a Cutting-Edge Solar Startup | Department of Energy  

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

The Story of a Cutting-Edge Solar Startup The Story of a Cutting-Edge Solar Startup The Story of a Cutting-Edge Solar Startup June 20, 2012 - 9:40am Addthis Erin R. Pierce Erin R. Pierce Digital Communications Specialist, Office of Public Affairs What does this project do? Watch the video to learn how Alta Devices manufacturers high performance solar cells at a low cost. Alta Devices is rethinking how high performance solar cells are made. The Silicon Valley startup has taken gallium arsenide -- an expensive semiconductor material that is incredibly efficient at turning sunlight into electricity -- and developed a commercially viable processes for manufacturing it into solar modules. In 2009, Alta Devices was selected to participate in the Energy Department's SunShot Incubator program. Now in its sixth iteration,

247

TVDG LET Calculator  

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

To The B N L Tandem Van de Graaff Accelerator To The B N L Tandem Van de Graaff Accelerator TVDG LET Calculator This program calculates the Peak LET, Corresponding Energy and Range as well as the LET and Range at the Specified Energy for the Specified Ion in the Specified Target. Select the Target Material from the dropdown list. Select the Ion Specie from the dropdown list. Enter the Total Ion Energy in the text box. This is equal to the Atomic Mass times the Energy/Nucleon. Click the 'Calculate' button or press the 'Enter' key. The Peak LET, Corresponding Energy and Range as well as the LET and Range at the Specified Energy for the Specified Ion in the Specified Target will be returned. Select your Target from the list Air Aluminum Oxide Carbon Copper Gallium Arsenide Gold Polyester Polyethylene Silicon Silicon Dioxide Skin Soda Lime Glass Sodium Iodide Water Select your Ion from the list

248

Definition: Semiconductor | Open Energy Information  

Open Energy Info (EERE)

Semiconductor Semiconductor Jump to: navigation, search Dictionary.png Semiconductor Any material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, gallium arsenide, copper indium diselenide, and cadmium telluride, are uniquely suited to the photovoltaic conversion process.[1] View on Wikipedia Wikipedia Definition A semiconductor is a material which has electrical conductivity to a degree between that of a metal (such as copper) and that of an insulator (such as glass). Semiconductors are the foundation of modern solid state electronics, including transistors, solar cells, light-emitting diodes (LEDs), quantum dots and digital and analog integrated circuits. A semiconductor may have a number of unique properties, one of which is the

249

NREL photovoltaic subcontract reports: Abstracts and document control information, 1 August 1991--31 July 1992  

DOE Green Energy (OSTI)

This report contains document control information and abstracts for the National Renewable Energy Laboratory (NREL) subcontracted photovoltaic program publications. It also lists source information on additional publications that describe US Department of Energy (DOE) PV research activities. It is not totally exhaustive, so it lists NREL contacts for requesting further information on the DOE and NREL PV programs. This report covers the period from August 1, 1991, through July 31, 1992. The purpose of continuing this type of publication is to help people keep abreast of specific PV interests, while maintaining a balance on the costs to the PV program. The information in this report is organized under PV technology areas: Amorphous silicon research; polycrystalline thin films (including copper indium diselenide, cadmium telluride, and thin-film silicon); crystalline materials and advanced concepts (including silicon, gallium arsenide, and other group III-V materials); and PV manufacturing technology development (which may include manufacturing information for various types of PV materials).

Not Available

1992-08-01T23:59:59.000Z

250

Polymer photovoltaic cells: enhanced efficiencies via a network of internal donor–acceptor heterojunctions  

E-Print Network (OSTI)

The carrier collection efficiency (?c) and energy conversion efficiency (?e) of polymer photovoltaic cells were improved by blending of the semiconducting polymer with C60 or its functionalized derivatives. Composite films of poly(2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and fullerenes exhibit ?c of about 29 percent of electrons per photon and ?e of about 2.9 percent, efficiencies that are better by more than two orders of magnitude than those that have been achieved with devices made with pure MEH-PPV. The efficient charge separation results from photoinduced electron transfer from the MEH-PPV (as donor) to C60 (as acceptor); the high collection efficiency results from a bicontinuous network of internal donor-acceptor heterojunctions. The need to develop inexpensive renewable energy sources continues to stimulate new approaches to production of efficient, lowcost photovoltaic devices. Although inorganic semiconductors (silicon, amorphous silicon, gallium arsenide, and sulfide

G. Yu; J. Gao; J. C. Hummelen; F. Wudl; A. J. Heeger

1995-01-01T23:59:59.000Z

251

Regenerative mode photo electrochemical cells in molten salt electrolytes. 1st four monthly report (1/31/80)  

DOE Green Energy (OSTI)

The most promising photoelectrodes selected for use in the butyl pyridinium chloride-aluminum chloride room temperature molten salt are n-type silicon, gallium arsenide and cadmium telluride. The solubilities of these semiconductors are low, and their conduction and valence band edges are favorably located. Cadmium selenide and sulfide showed significant solubility in the melt, and the conduction band edge for p-type cadmium telluride was too close to the aluminum deposition potential. Several reversible redox couples have been identified, which could potentially be used in a photoelectrochemical cell. These include W/sup 5 +//W/sup 6 +/ and Eu/sup 2 +//Eu/sup 3 +/ as well as ferrocene and its derivatives.

Not Available

1980-01-01T23:59:59.000Z

252

Electrochemical investigation of the gallium nitride-aqueous electrolyte interface  

SciTech Connect

GaN (E{sub g} = {approximately}3.4 eV) was photoelectrochemically characterized and the energetic position of its bandedges determined with respect to SHE. Electrochemical impedance spectroscopy was employed to analyze the interface, determine the space charge layer capacitance, and, subsequently obtain the flatband potential of GaN in different aqueous electrolytes. The flatband potential of GaN varied at an approximately Nernstian rate in aqueous buffer electrolytes of different pHs indicating acid-base equilibria at the interface.

Kocha, S.S.; Peterson, M.W.; Arent, D.J.; Turner, J.A. [National Renewable Energy Lab., Golden, CO (United States). Photoconversion Branch; Redwing, J.M.; Tischler, M.A. [Advanced Technology Materials, Inc., Danbury, CT (United States)

1995-12-01T23:59:59.000Z

253

SYNTHESIS OF HIGH-PURITY BULK COPPER INDIUM GALLIUM SELENIDE ...  

A sputtering target formed by the method can have an oxygen content of 10 ppm by weight, ... Biomass and Biofuels; Building Energy Efficiency; Electricity Transmission;

254

Superconductivity in gallium-substituted Ba8Si46 clathrates  

E-Print Network (OSTI)

We report a joint experimental and theoretical investigation of superconductivity in Ga-substituted type-I silicon clathrates. We prepared samples of the general formula Ba8Si46-xGax, with different values of x. We show that Ba8Si40Ga6 is a bulk superconductor, with an onset at T-C approximate to 3.3 K. For x=10 and higher, no superconductivity was observed down to T=1.8 K. This represents a strong suppression of superconductivity with increasing Ga content, compared to Ba8Si46 with T-C approximate to 8 K. Suppression of superconductivity can be attributed primarily to a decrease in the density of states at the Fermi level, caused by a reduced integrity of the sp(3)-hybridized networks as well as the lowering of carrier concentration. These results are corroborated by first-principles calculations, which show that Ga substitution results in a large decrease of the electronic density of states at the Fermi level, which explains the decreased superconducting critical temperature within the BCS framework. To further characterize the superconducting state, we carried out magnetic measurements showing Ba8Si40Ga6 to be a type-II superconductor. The critical magnetic fields were measured to be H-C1 approximate to 35 Oe and H-C2 approximate to 8.5 kOe. We deduce the London penetration depth lambda approximate to 3700 A and the coherence length xi(c)approximate to 200 A. Our estimate of the electron-phonon coupling reveals that Ba8Si40Ga6 is a moderate phonon-mediated BCS superconductor.

Li, Yang; Zhang, Ruihong; Liu, Yang; Chen, Ning; Luo, Z. P.; Ma, Xingqiao; Cao, Guohui; Feng, Z. S.; Hu, Chia-Ren; Ross, Joseph H., Jr.

2007-01-01T23:59:59.000Z

255

Nanoscale-Structured Gallium Nitride Pillars for Light-Emitting ...  

Science Conference Proceedings (OSTI)

... using top-down fabrication scheme, D. Paramanik, A. Motayed, GS Aluri, J.-Y. Ha, S. Krylyuk, AV Davydov, M. King, S. McLaughlin, S. Gupta, and H ...

2013-01-18T23:59:59.000Z

256

Nanofabrication of gallium nitride photonic crystal light-emitting diodes  

Science Conference Proceedings (OSTI)

We describe a comparison of nanofabrication technologies for the fabrication of 2D photonic crystal structures on GaN/InGaN blue LEDs. Such devices exhibit enhanced brightness and the possibility of controlling the angular emission profile of emitted ... Keywords: GaN dry-etching, Light-emitting diodes, Nanolithography, Photonic crystals

Ali Z. Khokhar; Keith Parsons; Graham Hubbard; Faiz Rahman; Douglas S. Macintyre; Chang Xiong; David Massoubre; Zheng Gong; Nigel P. Johnson; Richard M. De La Rue; Ian M. Watson; Erdan Gu; Martin D. Dawson; Steve J. Abbott; Martin D. B. Charlton; Martin Tillin

2010-11-01T23:59:59.000Z

257

Rutherford backscattering analysis of gallium implanted 316 stainless steel  

E-Print Network (OSTI)

Ion implantation of Ga ions into 316 stainless steel was performed at fluences ranging from 8x10¹? to 10¹? ions/cm². The depth profile of Ga in the steel was analyzed via Rutherford Backscattering and ToFSIMS. The surface effects were characterized with SEM analysis. Results indicate that Ga saturation was reached at fluences between 2-6x10¹? ions/cm². The maximum Ga concentration occurred near the surface and was between 20 and 25 atomic percent. A constant Ga concentration of 5% was attained at 300 [] and deeper. The possible enhanced diffusion of Ga was observed, but not necessarily through the grain boundaries. Although there was no indication of compound formation, significant pitting was observed at high fluences. Repassivation characteristics of stainless steel may be inhibited at high fluences; therefore future studies are recommended.

Ortensi, Javier

2000-01-01T23:59:59.000Z

258

Supply Chain Dynamics of Tellurium (Te), Indium (In), and Gallium...  

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

CdTe Solar Cells, Solar Energy Materials and Solar Cells, 90 (2006) 2263-2271. 3 CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, FL, 1986. 4 M.A. Green, K....

259

Analysis of photovoltaic/thermal electric power plant systems  

DOE Green Energy (OSTI)

A conceptual definition and performance evaluation of a 100 megawatt (MW) hybrid photovoltaic/thermal electric power plant has been carried out. The concept utilizes the ability of gallium arsenide photovoltaic cells to achieve high conversion efficiency at high incident fluxes and elevated temperatures. Solar energy is focused by a field of steerable mirrors (heliostats) onto a tower mounted receiver whose outer surface is covered with gallium arsenide (AlGaAs/GaAs) solar cells and whose inner surface is a water boiler. The solar cells convert a fraction of the incident radiation into electrical energy, and the remaining energy is extracted at approximately 200/sup 0/C and used to power a Rankine cycle turbine generator (bottoming cycle). Water is used as the solar cell array coolant, as the thermodynamic working fluid, and as the thermal energy storage medium. Parametric studies were conducted to select conceptual design parameters and operational characteristics which imply the lowest levelized busbar electric energy costs. Parameters varied were collector area, condenser surface area, fan power, ambient temperature, and electric and thermal energy storage capacities. The report describes the concept, outlines the design analysis method, summarizes the parametric study results, and defines the selected plant configuration. The lowest levelized busbar electric energy generation cost, 70 mills/kilowatt-hr., was achieved with a relatively small collector area, 0.8 x 10/sup 6/ square meters, and no stored energy. A rough comparison of this combined power plant with a similar photovoltaic plant, operated at lower solar cell temperature and with no bottoming cycle, showed the busbar cost of electricity (BBEC) from the combined system to be approximately 9% lower.

Gluck, D.F.; Kelley, W.A.

1979-03-01T23:59:59.000Z

260

Coherence and Spin in GaAs Quantum Dots  

E-Print Network (OSTI)

. The eletrical proper- ties of our thin films on the 101¯0 substrate are comparable with those of a single

Heller, Eric

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Low-energy positron diffraction from GaAs(110)  

Science Conference Proceedings (OSTI)

Intensities of 16 beams of near normal incidence positrons have been measured at {ital T}=120 K and analyzed using a multiple scattering model of the low-energy positron diffraction (LEPD) process. Excellent correspondence between the measured and calculated intensities is obtained for a reconstruction that is primarily a bond-length-conserving rotation of the top layer, with As relaxed outward and Ga inward with a tilt angle {omega}{sub 1} = 28.6 {plus minus} 3{degree}, confirming the results of previous structure analyses for this surface. The quality of the description of the measured intensities, as measured by the x-ray {ital R} factor, is significantly better for LEPD than for low-energy electron diffraction. This result is attributed to the repulsive character of the positron-ion core potential and a resulting more surface sensitive diffraction process for LEPD.

Lessor, D.L. (Pacific Northwest Laboratory, K5-17 ISB-1, Richland, Washington 99352 (United States)); Duke, C.B. (Xerox Webster Research Center, 800 Phillips Road, 0114-38D, Webster, New York 14580 (United States)); Chen, X.M.; Brandes, G.R.; Canter, K.F. (Department of Physics, Brandeis University, Waltham, Massachusetts 02254 (United States)); Ford, W.K. (Advanced Materials Center and Department of Physics, Montana State University, Bozeman, Montana 59717 (United States))

1992-07-01T23:59:59.000Z

262

Accelerated aging of GaAs concentrator solar cells  

DOE Green Energy (OSTI)

An accelerated aging study of AlGaAs/GaAs solar cells has been completed. The purpose of the study was to identify the possible degradation mechanisms of AlGaAs/GaAs solar cells in terrestrial applications. Thermal storage tests and accelerated AlGaAs corrosion studies were performed to provide an experimental basis for a statistical analysis of the estimated lifetime. Results of this study suggest that a properly designed and fabricated AlGaAs/GaAs solar cell can be mechanically rugged and environmentally stable with projected lifetimes exceeding 100 years.

Gregory, P.E.

1982-04-01T23:59:59.000Z

263

P2 Coordinators GAA Dist List Oct 06.doc  

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

) Robert (Bruce) Webster webster@netl.doe.gov 412-386-4475 National Petroleum & Oil Shale Reserves (CO, UT, WY) Michael Taylor mike.taylor@rmotc.doe.gov 307-437-9606...

264

Structural and physical properties of layered oxy-arsenides LnRuAsO (Ln=La, Nd, Sm, Gd)  

Science Conference Proceedings (OSTI)

Polycrystalline samples of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO have been synthesized and studied using powder x-ray diffraction, electrical transport, magnetization, and heat capacity measurements. Variations in structural properties across the series reveal a trend toward more ideal tetrahedral coordination around Ru as the size of the rare earth element is reduced. The lattice parameters of these Ru compounds show a more anisotropic response to variation in Ln than their Fe analogs, and significant anisotropy in thermal expansion is also observed. Transport measurements show metallic behavior, and carrier concentrations near 10{sup 21}-10{sup 22} electrons per cm{sup 3} are inferred from simple analysis of Hall effect measurements. Anomalies in resistivity, magnetization, and heat capacity indicate antiferromagnetic ordering of rare earth moments at 5 K for GdRuAsO, 4.5 K for SmRuAsO, and heat capacity of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO. Highlights: Black-Right-Pointing-Pointer Experimental investigation of LaRuAsO, NdRuAsO, SmRuAsO, and GdRuAsO. Black-Right-Pointing-Pointer Anisotropic lattice response to changing Ln radius and temperature. Black-Right-Pointing-Pointer Ru coordination becomes more ideal as Ln radius is reduced. Black-Right-Pointing-Pointer Transport measurements reveal metallic conduction dominated by electrons. Black-Right-Pointing-Pointer Magnetic measurements indicate antiferromagnetic ordering Nd, Sm, and Gd moments.

McGuire, Michael A., E-mail: McGuireMA@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); May, Andrew F.; Sales, Brian C. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2012-07-15T23:59:59.000Z

265

Recycling of wasted energy : thermal to electrical energy conversion  

E-Print Network (OSTI)

of Amorphous Gallium Indium Zinc Oxide NonvolatileAmorphous gallium indium zinc oxide thin film transistors:Effects in Amorphous Gallium–Indium Zinc- xv Oxide Thin Film

Lim, Hyuck

2011-01-01T23:59:59.000Z

266

Synthesis and characterization of visible emission from rare-earth doped aluminum nitride, gallium nitride and gallium aluminum nitride powders and thin films  

E-Print Network (OSTI)

to improve sealing and prevent the ingress of air, as shownimproved sealing and prevented the ingress of air, which

Tao, Jonathan Huai-Tse

2010-01-01T23:59:59.000Z

267

Self-organized GaAs patterns on misoriented GaAs (111)B substrates using dilute nitrides by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

Recently, the growth of patterned surfaces is being used to demonstrate the site control of the three-dimensional nanostructures, and in particular quantum dots. Nevertheless the pre-patterning techniques show some disadvantages. In this work, we report ... Keywords: Dilute nitrides, InAs, Molecular beam epitaxy, Patterned surface, Quantum dots

R. Gargallo; J. Miguel-Sánchez; Á. Guzmán; U. Jahn; E. Muñoz

2006-12-01T23:59:59.000Z

268

Chlorine adsorption on the InAs (001) surface  

Science Conference Proceedings (OSTI)

Chlorine adsorption on the In-stabilized InAs(001) surface with {zeta}-(4 Multiplication-Sign 2) and {beta}3 Prime -(4 Multiplication-Sign 2) reconstructions and on the Ga-stabilized GaAs (001)-{zeta}-(4 Multiplication-Sign 2) surface has been studied within the electron density functional theory. The equilibrium structural parameters of these reconstructions, surface atom positions, bond lengths in dimers, and their changes upon chlorine adsorption are determined. The electronic characteristics of the clean surface and the surface with adsorbed chlorine are calculated. It is shown that the most energetically favorable positions for chlorine adsorption are top positions over dimerized indium or gallium atoms. The mechanism of chlorine binding with In(Ga)-stabilized surface is explained. The interaction of chlorine atoms with dimerized surface atoms weakens surface atom bonds and controls the initial stage of surface etching.

Bakulin, A. V.; Eremeev, S. V. [Russian Academy of Sciences, Institute of Strength Physics and Materials Science, Siberian Branch (Russian Federation); Tereshchenko, O. E. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, sSiberian Branch (Russian Federation); Kulkova, S. E., E-mail: kulkova@ispms.tsc.ru [Russian Academy of Sciences, Institute of Strength Physics and Materials Science, Siberian Branch (Russian Federation)

2011-01-15T23:59:59.000Z

269

Photovoltaics: From the laboratory to the marketplace  

DOE Green Energy (OSTI)

Photovoltaics (PV), the direct conversion of sunlight to electricity, is experiencing significant improvements in technology performance and lowered costs. Fostering these improvements, the SERI Photovoltaic Advanced Research and Development (PV AR D) Project supports research and provides services to the US PV industry. This paper presents the recent advances and future direction of the PV project. Research areas are Fundamental and Supporting Research, Advanced Thin-Film Materials, High-Efficiency Materials, Module Development, and Systems Development. Materials of interest include amorphous silicon, copper indium diselenide, cadmium telluride, crystalline silicon, gallium arsenide and related alloys, transparent conductors, antireflection coatings, substrates, and encapsulants. The PV project inherently provides technology transfer that helps industry shorten the time to bring R D advances to the marketplace. SERI annually performs over 10,000 measurements for the entire PV community, participates in collaborative research, and welcomes visiting scientists. Two specific areas of recently increased national focus are: (1) manufacturing processes for cost-effective PV modules, and (2) systems development for high-value utility applications. The SERI research approach is based on facilitating direct contact between industry, electric utilities, and others interested in PV technology. This approach heavily relies on SERI/industry partnerships. The arrangements vary to address generic and company-specific problems to improve the US industry's competitive position and accelerate greater electric utility deployment of PV systems. 5 refs., 5 figs., 6 tabs.

Basso, T.S.; Surek, T.; Thornton, J.

1991-03-01T23:59:59.000Z

270

Inverted Metamorphic Multijunction (IMM) Cell Processing Instructions  

DOE Green Energy (OSTI)

This technical report details the processing schedule used to fabricate Inverted Metamorphic Multijunction (IMM) concentrator solar cells at The National Renewable Energy Laboratory (NREL). These devices are used as experimental test structures to support the research at NREL that is focused on increasing the efficiency of photovoltaic power conversion. They are not intended to be devices suitable for deployment in working concentrator systems primarily because of heat sinking issues. The process schedule was developed to be compatible with small sample sizes and to afford relatively rapid turn-around times, in support of research efforts. The report describes the use of electro deposition of gold for both the back and front contacts. Electro-deposition is used because of its rapid turn around time and because it is a benign metallization technique that is seldom responsible for damage to the semiconductors. The layer transfer technique is detailed including the use of a commercially available adhesive and the etching away of the parent gallium arsenide substrate. Photolithography is used to define front contact grids as well as the mesa area of the cell. Finally, the selective wet chemical etchant system is introduced and its use to reveal the back contact is described.

Duda, A.; Ward, S.; Young, M.

2012-02-01T23:59:59.000Z

271

Mission analysis of photovoltaic solar energy conversion. Volume IV. Supplementary studies  

DOE Green Energy (OSTI)

A discussion is presented of the most significant problems associated with the production and deployment of photovoltaic arrays. The principal chemical compounds to be used in the manufacture of silicon, gallium arsenide, and cadmium sulfide photovoltaic arrays are discussed with respect to physical and chemical properties, sources of the raw materials required to extract or synthesize these materials, the methods of manufacture, storage and handling in large quantities, transportation restrictions, spills, leaks, ignition and explosion. A discussion of safety hazards associated with the finished products is followed by an analysis of the toxicological properties of all raw, refined, and finished chemical species involved. The principal tool used in the evaluation of incentive strategies was a new Public Utility Financial Analysis and Planning Model which is described in some detail. After adaptation to match the characteristics of photovoltaic plants, it was used in the comparative evaluation of six different incentive strategies. The candidate strategies, the rationale for their selection, and the results of the comparative evaluation are presented. An account is given of an attempt to assess the full non-internalized costs of coal-fired power generation. A detailed description is given of the various damage elements and their associated societal costs for coal production, coal transportation, and coal-fired power generation. (MHR)

Leonard, S. L.; Breisacher, P.; Munjal, P. K.; Neiss, J. A.

1977-03-01T23:59:59.000Z

272

Environmental assessment for the satellite power system concept development and evaluation program: atmospheric effects  

DOE Green Energy (OSTI)

The US Department of Energy (DOE) has undertaken a preliminary, three-year program to investigate the impacts of the construction and operation of a satellite power system, of unprecedented scale. The Department of Energy's program, titled The Concept Development and Evaluation Program, focused its investigations on a Reference System description that calls for the use of either silicon (Si) or gallium aluminum-arsenide (GaAlAs) photovoltaic cells on 60 satellites to be constructed in GEO over a 30-yr period. Rectennas would be constructed on the ground to receive microwave energy from the satellites. Each satellite-rectenna pair is designed to produce 5 GW of power on an essentially continuous basis for use as a baseload power source for an electric power distribution system. The environmental assessment part of the program was divided into five interdependent task areas. The present document constitutes the final technical report on one of the five task areas, the Assessment of the Atmospheric Effects, and as such presents an in-depth summary of work performed during the assessment program. The issues associated with SPS activities in the troposphere are examined. These include tropospheric weather modification related to rectenna operations and rocket launches, and air quality impacts related to rocketlaunch ground clouds. Then progressing upward through the various levels of the atmosphere, the principal middle and upper atmospheric effects associated with rocket effluents are analyzed. Finally, all of the potential SPS atmospheric effects are summarized.

Rote, D.M.; Brubaker, K.L.; Lee, J.L.

1980-11-01T23:59:59.000Z

273

PVT -- A photovoltaic/thermal concentrator total energy system: Final phase 1 project report. Building opportunities in the U.S. for photovoltaics (PV:BONUS) Two  

DOE Green Energy (OSTI)

United Solar completed its Phase 1 report and its proposal for Phase 2 of the PVBONUS Two program at the end of March 1998. At the same time, it also completed and submitted a proposal to the California Energy Commission PIER program for additional funding to cost-share development and testing of a pre-production model of the PVT-14. It was unsuccessful in both of these proposed efforts. While waiting for the proposal decisions, work continued in April and May to analyze the system design and component decisions described below. This document is a final summation report on the Phase 1 effort of the PVBONUS Two program that describes the key technical issues that United Solar and its subcontractor, Industrial Solar Technology Corporation, worked on in preparation of a Phase 2 award. The decisions described were ones that will guide the design and fabrication of a pre-production prototype of a 1500:1 mirrored concentrator with gallium arsenide cells when United solar resumes its development work. The material below is organized by citing the key components that underwent a design review, what the company considered, what was decided, the name of the expected supplier, if not to be produced in-house, and some information about expected costs. The cost figures given are usually budgetary estimates, not the result of firm quotations or extensive analysis.

NONE

1998-12-31T23:59:59.000Z

274

NREL photovoltaic subcontract reports: Abstracts and document control information, 1 August 1992--31 July 1993  

DOE Green Energy (OSTI)

This report contains document control information and abstracts for the National Renewable Energy Laboratory (NREL) subcontracted photovoltaic (PV) program publications. It also lists source information on additional publications that describe US Department of Energy (DOE) PV research activities. It is not totally exhaustive, so it lists NREL contacts for requesting further information on the DOE and NREL PV programs. This report covers the period from August 1, 1992, through July 31, 1993. This report is published periodically, with the previous one covering the period from August 1, 1991, through July 31, 1992. The purpose of continuing this type of publication is to help keep people abreast of specific PV interests, while maintaining a balance on the costs to the PV program. The information in this report is organized under PV technology areas: Amorphous Silicon Research; Polycrystalline Thin Films (including copper indium diselenide, cadmium telluride, and thin-film silicon); Crystalline Materials and Advanced Concepts (including silicon, gallium arsenide, and other group III-V materials); PV Manufacturing Technology Development (which may include manufacturing information for various types of PV materials).

Not Available

1993-09-01T23:59:59.000Z

275

Gallium Safety in the Laboratory INEEL/CON-03-00078  

Office of Scientific and Technical Information (OSTI)

This is a preprint of a paper intended for publication in a This is a preprint of a paper intended for publication in a journal or proceedings. Since changes may be made before publication, this preprint should not be cited or reproduced without permission of the author. This document was prepared as a account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this paper are

276

Analysis of amorphous indium-gallium-zinc-oxide thin-film transistor contact metal  

E-Print Network (OSTI)

, 157-159 (2008). 22 W.L. Bragg, Philosophical Magazine Series 6, 40:236, 169-189 (1920). 23 N.E. Holden, Pure & Appl. Chem. 52, 2349-2384 (1979). 24 J.F. Shackelford and W. Alexander, Materials science and engineering handbook, ed. 3. (CRC...

Kiani, Ahmed; Hasko, David G.; Milne, William I.; Flewitt, Andrew J.

2013-04-15T23:59:59.000Z

277

Synthesis, Structure, and Molecular Dynamics of Gallium Complexes of Schizokinen and the Amphiphilic  

E-Print Network (OSTI)

). The activation parameters found for the two sequential steps of the proton independent pathway were Hq ) 25 ( 3 kcal M-1 , Sq ) 25 ( 7 cal M-1 K-1 and Hq ) 17.1 ( 0.2 kcal M-1 , Sq ) 0.3 ( 2.7 cal M-1 K-1 organic compounds that are produced by microorganisms in response to iron deficiency. These compounds

Groves, John T.

278

Dependence of carrier mobility on an electric field in gallium selenide crystals  

Science Conference Proceedings (OSTI)

The dependence of the mobility of charge carriers on voltage has been studied in undoped GaSe single crystals and crystals doped with gadolinium; the latter crystals have exhibited various values of dark resistivity ({rho}{sub d.r} Almost-Equal-To 10{sup 4}-10{sup 8} {Omega} cm at 77 K) and of the doping level (N = 10{sup -5}, 10{sup -4}, 10{sup -3}, 10{sup -2}, and 10{sup -1} at %). It is established that the dependence of the charge-carrier mobility on the electric field applied to the sample E {=} 10{sup 4} {Omega} cm) and in lightly doped GaSe crystals (N {<=} 10{sup -2} at %) in the region of T {<=} 150 K. It is found that this dependence is not related to heating of the charge carriers by an electric field; rather, it is caused by elimination of drift barriers as a result of injection.

Abdinov, A. Sh., E-mail: abdinov_axmed@yahoo.com; Babaeva, R. F., E-mail: Babaeva-Rena@yandex.ru; Rzayev, R. M. [Baku State University (Azerbaijan)

2012-06-15T23:59:59.000Z

279

Structure and electronic properties of saturated and unsaturated gallium nitride nanotubes  

DOE Green Energy (OSTI)

The atomic and electronic structures of saturated and unsaturated GaN nanotubes along the [001] direction with (100) lateral facets are studied using first-principles calculations. Atomic relaxation of nanotubes shows that appreciable distortion occurs in the unsaturated nanotubes. All the nanotubes considered, including saturated and unsaturated ones, exhibit semiconducting, with a direct band gap. Surface states arisen from the threefold-coordinated N and Ga atoms at the lateral facets exist inside the bulk-like band gap. When the nanotubes saturated with hydrogen, these dangling bond bands are removed from the band gap, but the band gap decreases with increasing the wall thickness of the nanotubes.

Wang, Zhiguo; Wang, Shengjie; Li, Jingbo; Gao, Fei; Weber, William J.

2009-11-05T23:59:59.000Z

280

ISOTHERMAL (DELTA)/(ALPHA-PRIME) TRANSFORMATION AND TTT DIAGRAM IN A PLUTONIUM GALLIUM ALLOY  

Science Conference Proceedings (OSTI)

Differential scanning calorimetry (DSC) is used as an alternative approach to determining the tine-temperature-transformation (TTT) diagram for the martensitic delta to alpha-prime transformation in a Pu-2.0 at% Ga alloy. Previous work suggests that the TTT diagram for a similar alloy exhibits an unusual double-C curve for isothermal holds of less than 100 minutes. Here, we extend this diagram to 18 hours, and confirm the double-C curve behavior. When the sample is cooled prior to the isothermal holds, the delta to alpha-prime transformation is observed as several overlapping exothermic peaks. These peaks are very reproducible, and they are believed to be the result of different kinds of delta to alpha-prime martensitic transformation. This may be due to the presence of different nucleation sites and/or different morphologies.

Oudot, B P; Blobaum, K M; Wall, M A; Schwartz, A J

2005-11-11T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Synthesis, characterization, and biotemplated assembly of indium nitride and indium gallium nitride nanoparticles  

E-Print Network (OSTI)

A low-temperature, ambient pressure solution synthesis of colloidal InN nanoparticles is presented. This synthesis utilizes a previously dismissed precursor and results in individual, non-aggregated nanoparticles with ...

Hsieh, Jennifer Chia-Jen

2010-01-01T23:59:59.000Z

282

GaN CVD Reactions: Hydrogen and Ammonia Decomposition and the Desorption of Gallium  

DOE Green Energy (OSTI)

Isotopic labeling experiments have revealed correlations between hydrogen reactions, Ga desorption, and ammonia decomposition in GaN CVD. Low energy electron diffraction (LEED) and temperature programmed desorption (TPD) were used to demonstrate that hydrogen atoms are available on the surface for reaction after exposing GaN(0001) to deuterium at elevated temperatures. Hydrogen reactions also lowered the temperature for Ga desorption significantly. Ammonia did not decompose on the surface before hydrogen exposure. However, after hydrogen reactions altered the surface, N15H3 did undergo both reversible and irreversible decomposition. This also resulted in the desorption of N2 of mixed isotopes below the onset of GaN sublimation, This suggests that the driving force of the high nitrogen-nitrogen bond strength (226 kcal/mol) can lead to the removal of nitrogen from the substrate when the surface is nitrogen rich. Overall, these findings indicate that hydrogen can influence G-aN CVD significantly, being a common factor in the reactivity of the surface, the desorption of Ga, and the decomposition of ammonia.

Bartram, Michael E.; Creighton, J. Randall

1999-05-26T23:59:59.000Z

283

The Interfacial Mechanics of the Thin Oxide Skin on Liquid Gallium ...  

Science Conference Proceedings (OSTI)

The ability to micromold the metal for these applications is enabled by the ... The oxide skin is elastic and yields under a critical stress, at which point the metal flows. ... Interface Bond Strength of HIP-Clad Depleted Uranium and 6061- Aluminum ... Quantitative NanoSIMS Analysis of Grain Boundary Segregation in Bulk ...

284

Diffusion, Uptake and Release of Hydrogen in p-type Gallium Nitride: Theory and Experiment  

DOE Green Energy (OSTI)

The diffusion, uptake, and release of H in p-type GaN are modeled employing state energies from density-function theory and compared with measurements of deuterium uptake and release using nuclear-reaction analysis. Good semiquantitative agreement is found when account is taken of a surface permeation barrier.

MYERS JR.,SAMUEL M.; WRIGHT,ALAN F.; PETERSEN,GARY A.; WAMPLER,WILLIAM R.; SEAGER,CARLETON H.; CRAWFORD,MARY H.; HAN,JUNG

2000-06-27T23:59:59.000Z

285

The equilibrium state of hydrogen in gallium nitride: Theory and experiment  

DOE Green Energy (OSTI)

Formation energies and vibrational frequencies for H in wurtzite GaN were calculated from density functional theory and used to predict equilibrium state occupancies and solid solubilities for p-type, intrinsic, and n-type material. The solubility of deuterium (D) was measured at 600--800 C as a function of D{sub 2} pressure and doping and compared with theory. Agreement was obtained by reducing the H formation energies 0.2 eV from ab-initio theoretical values. The predicted stretch-mode frequency for H bound to the Mg acceptor lies 5% above an observed infrared absorption attributed to this complex. It is concluded that currently recognized H states and physical processes account for the equilibrium behavior of H examined in this work.

MYERS JR.,SAMUEL M.; WRIGHT,ALAN F.; PETERSEN,GARY A.; SEAGER,CARLETON H.; WAMPLER,WILLIAM R.; CRAWFORD,MARY H.; HAN,JUNG

2000-04-17T23:59:59.000Z

286

Scintigraphic evaluation of Lyme disease: Gallium-67 imaging of Lyme myositis  

Science Conference Proceedings (OSTI)

A patient suffering from Lyme disease had cardiac conduction abnormalities, symptoms of arthritis, and myalgia. A Ga-67 image showed evidence of endomyocarditis, but intense skeletal muscle uptake pointed to Lyme myositis. Reference is made to two other case reports of Lyme myositis.

Kengen, R.A.; v.d. Linde, M.; Sprenger, H.G.; Piers, D.A. (Univ. Hospital, Groningen (Netherlands))

1989-10-01T23:59:59.000Z

287

Preconceptual Design For Separation Of Plutonium And Gallium By Ion Exchange  

E-Print Network (OSTI)

.............................................................................. 5 2.0 BACKGROUND.........................................................................5 3.0 PROCESS DESCRIPTION.............................................................6 3.1 Oxidation of Metal...............................................................7 3.2 Dissolution of Oxide............................................................ 8 3.3 Ion Exchange (IX).............................................................. 8 3.4 Plutonium Product Preparation................................................ 10 3.5 Recycle Operations..............................................................10 3.6 Waste Generation................................................................10 4.0 MATERIAL BALANCES...............................................................11 4.1 Dissolution of Oxide............................................................ 11 4.2 IX Feed Pretreatment.............................

Scott Demuth; Scott F. Demuth

1997-01-01T23:59:59.000Z

288

Radiation-Hardened Gallium Nitride Detector and Arrays for Fusion Diagnostics  

Science Conference Proceedings (OSTI)

This poster reports testing to confirm that GaN devices exhibit the extreme radiation hardness needed for use at the NIF, functioning properly after 1x10{sup 12} protons/cm{sup 2} proton irradiation in one year.

Sun, K. X., and MacNeil, L.

2011-09-08T23:59:59.000Z

289

SAGE: Solar Neutrino Data from SAGE, the Russian-American Gallium Solar Neutrino Experiment  

DOE Data Explorer (OSTI)

SAGE is a solar neutrino experiment based on the reaction 71Ga + n goes to 71Ge + e-. The 71Ge atoms are chemically extracted from a 50-metric ton target of Ga metal and concentrated in a sample of germane gas mixed with xenon. The atoms are then individually counted by observing their decay back to 71Ga in a small proportional counter. The distinguishing feature of the experiment is its ability to detect the low-energy neutrinos from proton-proton fusion. These neutrinos, which are made in the primary reaction that provides the Sun's energy, are the major component of the solar neutrino flux and have not been observed in any other way. To shield the experiment from cosmic rays, it is located deep underground in a specially built facility at the Baksan Neutrino Observatory in the northern Caucasus mountains of Russia. Nearly 100 measurements of the solar neutrino flux have been made during 1990-2000, and their combined result is a neutrino capture rate that is well below the prediction of the Standard Solar Model. The significant suppression of the solar neutrino flux that SAGE and other solar neutrino experiments have observed gives a strong indication for the existence of neutrino oscillations. [copied from the SAGE homepage at http://ewi.npl.washington.edu/SAGE/SAGE.html

SAGE Collaboration

290

Transparent Conducting Contacts Based on Zinc Oxide Substitutionally Doped with Gallium: Preprint  

DOE Green Energy (OSTI)

Transparent conducting oxides (TCOs) are a critical element in photovoltaic devices. This paper describes research on Ga:ZnO (a TCO candidate) using a high-throughput combinatorial approach.

Gorrie, C. W.; Reese, M.; Perkins, J. D.; Alleman, J. L.; Dabney M. S.; To, B.; Ginley, D. S.; Berry, J. J.

2008-05-01T23:59:59.000Z

291

Synthesis and optical properties of CsC1-doped gallium-sodium-sulfide glasses  

SciTech Connect

Ga{sub 2}S{sub 3}-Na{sub 2}S (GNS) glasses doped with CsCl were synthesized in open crucibles under inert atmosphere. The evaporative loss of CsCl during glass melting was measured by energy dispersive X-ray spectroscopy and corrected for by biasing the CsCl concentration in the mixture of starting materials to obtain glasses with accurately controlled stoichiometry. Glass transition temperatures, refractive index dispersions, and band edge energies were measured for four GNS:CsCl glasses, and the respective values were found to significantly improve over earlier studies that did not mitigate CsCl evaporative losses. The refractive index dispersion measurements indicate that the Cs{sup +} and Cl{sup -} radii are 16% larger in GNS:CsCl glass than in bulk crystalline CsCl. The band edge energy increases from 2.97 eV in GNS glass to 3.32 eV in GNS glass doped with 20 mol% CsCl as a result of introducing Cl{sup -} ions having a large optical electronegativity. The large bandgap of 3.32 eV and the low (450 cm{sup -1}) phonon energy make GNS:20%CsCl an attractive host material for rare-earth ions with radiative transitions in the near ultra-violet, visible, and near-infrared spectral regions.

Hehlen, Markus P [Los Alamos National Laboratory; Bennett, Bryan L [Los Alamos National Laboratory; Williams, Darrick J [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Castro, Alonso [Los Alamos National Laboratory; Tornga, Stephanie C [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

292

Commercialization of gallium nitride nanorod arrays on silicon for solid-state lighting  

E-Print Network (OSTI)

One important component in energy usage is lighting, which is currently dominated by incandescent and fluorescent lamps. However, due to potentially higher efficiencies and thus higher energy savings, solid-state lighting ...

Wee, Qixun

2008-01-01T23:59:59.000Z

293

Crystallographic and magnetic phase transitions in the layered ruthenium oxy-arsenides TbRuAsO and DyRuAsO  

Science Conference Proceedings (OSTI)

The crystallographic and physical properties of TbRuAsO and DyRuAsO at and below room temperature are reported, including full structure refinements from powder X-ray diffraction data and measured electrical and thermal transport properties, magnetic susceptibility, and heat capacity. Both compounds are isostructural to LaFeAsO (ZrCuSiAs-type, P4/nmm) at room temperature. However, DyRuAsO undergoes a symmetry-lowering crystallographic phase transition near 25 K, and adopts an orthorhombic structure (Pmmn) below this temperature. This structural distortion is unlike those observed in the analogous Fe compounds. Magnetic phase transitions are observed in both compounds which suggest antiferromagnetic ordering of lanthanide moments occurs near 7.0 K in TbRuAsO and 10.5 K in DyRuAsO. The nature of the structural distortion as well as thermal conductivity and heat capacity behaviors indicate strong coupling between the magnetism and the lattice. The behaviors of both materials show magnetic ordering of small moments on Ru may occur at low temperatures.

McGuire, Michael A [ORNL; May, Andrew F [ORNL; Sales, Brian C [ORNL

2012-01-01T23:59:59.000Z

294

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

295

Size Effect on the Mechanical Behaviour of GaAs Nanowires  

Science Conference Proceedings (OSTI)

Multiple-Stripe Lithiation Mechanism of Individual SnO2 Nanowires in a Flooding Geometry · Multiscale Modeling of Anisotropic Growth in Lithiated Silicon ...

296

Performance of GAASP/GAAS Superlattice Photocathodes in High Energy Experiments using Polarized Electrons  

Science Conference Proceedings (OSTI)

The GaAsP/GaAs strained superlattice photocathode structure has proven to be a significant advance for polarized electron sources operating with high peak currents per microbunch and relatively low duty factor. This is the characteristic type of operation for SLAC and is also planned for the ILC. This superlattice structure was studied at SLAC [1], and an optimum variation was chosen for the final stage of E-158, a high-energy parity violating experiment at SLAC. Following E-158, the polarized source was maintained on standby with the cathode being re-cesiated about once a week while a thermionic gun, which is installed in parallel with the polarized gun, supplied the linac electron beams. However, in the summer of 2005, while the thermionic gun was disabled, the polarized electron source was again used to provide electron beams for the linac. The performance of the photocathode 24 months after its only activation is described and factors making this possible are discussed.

Brachmann, A.; Clendenin, J.E.; Maruyama, T.; Garwin, E.L.; Ioakemidi, K.; Prescott, C.Y.; Turner, J.L.; /SLAC; Prepost, R.; /Wisconsin U., Madison

2006-02-27T23:59:59.000Z

297

F5, Large Area Growth of GaAs Solar Cell Based on Nanowire ...  

Science Conference Proceedings (OSTI)

G2, ZnSnN2: A New Earth-Abundant Semiconductor for Solar Energy Conversion · G3, Electrodeposition of Indium Sulfide Films from Organic Electrolytes.

298

GaAs series connected photovoltaic converters for high voltage capacitor charging applications  

DOE Green Energy (OSTI)

This report describes the design features of series connected photovoltaic arrays which will be required to charge capacitors to relatively high (400V) voltages in time periods on the order of 1 microsecond. The factors which determine the array voltage and the capacitor charge time are given. Individual element junction designs, along with an interconnect scheme, and a semiconductor process to realize them are presented. Finally, the input laser optical required to meet the requirements is determined.

Rose, B.H.

1997-09-01T23:59:59.000Z

299

Development and fabrication of advanced cover glass for a GaAs solar cell  

DOE Green Energy (OSTI)

This report summarizes work on improving solar cell conversion efficiencies by modifying the cell cover glass. Two approaches were investigated during the course of this work: grooved cover glasses to reduce the effect of top contact obscuration and secondary concentrators to improve concentrator solar cell performances in tracking modules. The grooved cover glass work used an array of metallized V shaped grooves in a thin cover glass (plastic) window to deflect incident light rays away from solar cell front surface regions covered by the solar cell electrical contact metallization onto unobstructed, optically active regions of the solar cell. Secondary concentrators are being considered for use on concentrator solar cells to improve overall system conversion efficiency and reduce receiver module cost. Secondary concentrators designed and fabricated during this project consist of small glass cones to attach directly to the top of the receiver solar cell. When appropriately designed, these secondary concentrator glass cones increase sunlight concentration on the solar cell, improve solar flux uniformity on the cell, improve system tolerance to tracking error, and allow for concentration ratios greater than can be ordinarily achieved with acrylic Fresnel lenses.

Borden, P.G.; Kaminar, N.R.; Grounner, M.

1984-01-01T23:59:59.000Z

300

MINORITY CARRIER TRAP MEASUREMENTS IN SCHOTTKY BARRIER S ON N-TYPE LPE GaAs  

E-Print Network (OSTI)

, T. and JEPPSON, B., Japan J. Appl. Phys. 12 (1973) 7. [6] HASEGAWA, F. and MAJERFELD, A., Electron

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

P8, Fabrication of Subwavelength Pillar Arrays on GaAs by Confined ...  

Science Conference Proceedings (OSTI)

DD3, A New Approach to Make ZnO-Cu2O Heterojunctions for Solar Cells ... E2, AlGaAs/GaAs/GaN Wafer Fused HBTs with Ar Implanted Extrinsic Collectors.

302

Exciton localization mechanisms in wurtzite/zinc-blende GaAs nanowires  

E-Print Network (OSTI)

, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom 2Laboratoire des Mate´riaux Semiconducteurs, Ecole Polytechnique Fe´de´rale de Lausanne, 1015 Lausanne, Switzerland 3Walter Schottky Institut and Physik Department, Technische... et al. PHYSICAL REVIEW B 87, 125304 (2013) *Corresponding author: pmc53@cam.ac.uk †Present address: IBM Zurich Research Laboratory, CH-8803 Ru¨schlikon, Switzerland. 1P. Caroff, K. A. Dick, J. Johansson, M. E. Messing, K. Deppert, and L. Samuelson...

Graham, Alexandra; Corfdir, Pierre; Heiss, Martin; Conesa-Boj, Sonia; Uccelli, Emanuele; Fontcuberta i Morral, Anna; Phillips, Richard

303

EE5, Growth and Thermal Conductivity of Polycrystalline GaAs ...  

Science Conference Proceedings (OSTI)

A simple yet extensively used configuration for thermal management in high .... Microstructure and Properties of Colloidal ITO Films and Cold-Sputtered ITO Films .... Hybrid Inorganic-Organic Molecular Magnets on an Ultrathin Insulating Film.

304

Radiation-induced surface degradation of GaAs and high electron mobility transistor structures  

Science Conference Proceedings (OSTI)

Transistor heterostructures with high-carrier-mobility have been studied. It is shown that, as the {gamma}-irradiation dose {Phi} increases, their degradation occurs in the following sequence. (i) At {Phi} 0.2-eV decrease in the diffusion energy of intrinsic defects and, probably, atmospheric oxygen. (ii) At {Phi} > 10{sup 7} rad, highly structurally disordered regions larger than 1 {mu}m are formed near microscopic defects or dislocations. (iii) At {Phi} > 10{sup 8} rad, there occurs degradation of the internal AlGaAs/InGaAs/GaAs interfaces and the working channel. An effective method for studying the degradation processes in heterostructures is to employ a set of structural diagnostic methods to analyze processes of radiation-induced and aging degradation, in combination with theoretical simulation of the occurring processes.

Bobyl, A. V.; Konnikov, S. G.; Ustinov, V. M.; Baidakova, M. V.; Maleev, N. A.; Sakseev, D. A. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Konakova, R. V., E-mail: konakova@isp.kiev.ua; Milenin, V. V.; Prokopenko, I. V. [National Academy of Sciences of Ukraine, Lashkaryov Institute of Semiconductor Physics (Ukraine)

2012-06-15T23:59:59.000Z

305

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

DOE Green Energy (OSTI)

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

306

High Efficiency Nanostructured III-V Photovoltaics for Solar Concentrator Application  

DOE Green Energy (OSTI)

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

307

Using the genetic algorithm to design gallium indium nitride/gallium nitride light-emitting diodes with reduced efficiency droop and reduced spectral instability with respect to injection current  

Science Conference Proceedings (OSTI)

Today we are witnessing a fast growing trend that is redefining the concept of lighting. Numerous governments from all over the world have passed legislation to phase out incandescent light bulbs, with the objective of encouraging energy-efficient ...

Roya Mirhosseini / Partha S. Dutta

2010-01-01T23:59:59.000Z

308

Investigation of Tunable Diode Spectroscopy for Monitoring Gases in Geothermal Plants  

Science Conference Proceedings (OSTI)

The results of an investigation directed at the development of instrument-tation for the real-time monitoring of gases, such as hydrogen sulfide (H2S) and chloride (HCl), in geothermal process streams is described. The geothermal power industry has an interest in the development of new low maintenance techniques since improved capabilities could lead to considerable cost savings through the optimization of various gas abatement processes. Tunable diode laser spectroscopy was identified as a candidate tech-nology for this application and a commercial instrument was specified and procured for testing. The measurement principle involved the use of solid state diode lasers and frequency modulation techniques. The gallium arsenide diode lasers employed emit light in the 0.7 to 2.0 micron region of the electromagnetic spectrum. This region contains the overtone and combination absorption bands of a number of species of industrial interest, including H2S and HCl. A particular device can be tuned over a small range to match the absorption line by changing its applied temperature and current. The diode current can also be sinusoidally modulated in frequency as it is tuned across the line. This modulation allows measurements to be conducted at frequencies where the laser intensity noise is minimal; and therefore, very high signal-to-noise measurements are possible. The feasibility of using this technology in various types of geothermal process streams has been explored. The results of laboratory and field studies are presented along with new advances in laser technology that could allow more sensitive and selective measurements to be performed.

J. K. Partin

2006-08-01T23:59:59.000Z

309

Satellite power system. Concept development and evaluation program  

DOE Green Energy (OSTI)

The Reference System description emphasizes technical and operational information required in support of environmental, socioeconomic, and comparative assessment studies. Supporting information has been developed according to a guideline of implementing two 5 GW SPS systems per year for 30 years beginning with an initial operational data of 2000 and with SPS's being added at the rate of two per year (10 GW/year) until 2030. The Reference System concept, which features gallium--aluminum--arsenide (GaAlAs) and silicon solar cell options, is described in detail. The concept utilizes a planar solar array (about 55 km/sup 2/) built on a graphite fiber reinforced thermoplastic structure. The silicon array uses a concentration ratio of one (no concentration), whereas the GaAlAs array uses a concentration ratio of two. A one-kilometer diameter phased array microwave antenna is mounted on one end. The antenna uses klystrons as power amplifiers with slotted waveguides as radiating elements. The satellite is constructed in geosynchronous orbit in a six-month period. The ground receiving stations (rectenna) are completed during the same time period. The other two major components of an SPS program are (1) the construction bases in space and launch and mission control bases on earth and (2) fleets of various transportation vehicles that support the construction and maintenance operations of the satellites. These transportation vehicles include Heavy Lift Launch Vehicles (HLLV), Personnel Launch Vehicles (PLV), Cargo Orbit Transfer Vehicles (COTV), and Personnel Orbit Transfer Vehicles (POTV). The earth launch site chosen is the Kennedy Space Center, pending further study.

Not Available

1978-10-01T23:59:59.000Z

310

Electrical and optical performance characteristics of 0.74eV p/n InGaAs monolithic interconnected modules  

DOE Green Energy (OSTI)

There has been a traditional trade-off in thermophotovoltaic (TPV) energy conversion development between system efficiency and power density. This trade-off originates from the use of front surface spectral controls such as selective emitters and various types of filters. A monolithic interconnected module (MIM) structure has been developed which allows for both high power densities and high system efficiencies. The MIM device consists of many individual indium gallium arsenide (InGaAs) cells series-connected on a single semi-insulating indium phosphide (InP) substrate. The MIM is exposed to the entire emitter output, thereby maximizing output power density. An infrared (IR) reflector placed on the rear surface of the substrate returns the unused portion of the emitter output spectrum back to the emitter for recycling, thereby providing for high system efficiencies. Initial MIM development has focused on a 1 cm{sup 2} device consisting of eight series interconnected cells. MIM devices, produced from 0.74 eV InGaAs, have demonstrated V{sub oc} = 3.2 volts, J{sub sc} = 70 mA/cm{sup 2} and a fill factor of 66% under flashlamp testing. Infrared (IR) reflectance measurements (> 2 {micro}m) of these devices indicate a reflectivity of > 82%. MIM devices produced from 0.55 eV InGaAs have also been demonstrated. In addition, conventional p/n InGaAs devices with record efficiencies (11.7% AM0) have been demonstrated.

Wilt, D.M.; Weizer, V.G. [National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center; Fatemi, N.S.; Jenkins, P.P.; Hoffman, R.W. Jr. [Essential Research Inc., Cleveland, OH (United States); Jain, R.K. [National Research Council, Washington, DC (United States); Murray, C.S.; Riley, D.R. [Westinghouse Electric Corp., West Mifflin, PA (United States)

1997-06-01T23:59:59.000Z

311

DESIGN AND ANALYSIS OF AN INTEGRATED PULSE MODULATED S-BAND POWER AMPLIFIER IN GALLIUM NITRIDE PROCESS  

SciTech Connect

The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might have been identified through a more rigorous approach to stability analysis. Designing for stability is probably the one area of amplifier design that receives the least amount of attention but incurs the most catastrophic of effects if it is not performed properly. Other parameters such as gain, power output, frequency response and even matching may suitable mitigation paths. But the lack of stability in an amplifier has no mitigating path. In addition to of loss of the design completely there are the increased production cycle costs, costs involved with investigating and resolving the problem and the costs involved with schedule slips or delays resulting from it. The Linville or Rollett stability criteria that many microwave engineers follow and rely exclusively on is not sufficient by itself to ensure a stable and robust design. It will be shown that the universal belief that unconditional stability is obtained through an analysis of the scattering matrix S to determine if 1 and |{Delta}{sub S}| < 1 is only part of the procedure and other tools must be used to validate the criteria. The research shown contributes to the state of the art by developing a more thorough stability design technique for designing amplifiers of any class, whether that be current mode or switch mode, than is currently undertaken with the goal of obtaining first pass design success.

STEVE SEDLOCK

2012-04-04T23:59:59.000Z

312

High temperature step-flow growth of gallium phosphide by molecular beam epitaxy and metalorganic chemical vapor deposition  

Science Conference Proceedings (OSTI)

Post-growth surface morphologies of high-temperature homoepitaxial GaP films grown by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) have been studied. Smooth, stepped surface morphologies of MBE-grown layers, measured by atomic force microscopy, were found for a wide range of substrate temperatures and P{sub 2}:Ga flux ratios. A MOCVD-based growth study performed under similar conditions to MBE-grown samples shows a nearly identical smooth, step-flow surface morphology, presenting a convergence of growth conditions for the two different methods. The additional understanding of GaP epitaxy gained from this study will impact its use in applications that include GaP-based device technologies, III-V metamorphic buffers, and III-V materials integration with silicon.

Ratcliff, C. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Grassman, T. J.; Ringel, S. A. [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Institute for Materials Research, Ohio State University, Columbus, Ohio 43210 (United States); Carlin, J. A. [Institute for Materials Research, Ohio State University, Columbus, Ohio 43210 (United States)

2011-10-03T23:59:59.000Z

313

Förster Resonance Energy Transfer Mediated White-Light-Emitting Rhodamine Fluorophore Derivatives-Gamma Phase Gallium Oxide Nanostructures.  

E-Print Network (OSTI)

??The global lighting source energy consumption accounts for about 22% of the total electricity generated. New high-efficiency solid-state light sources are needed to reduce the… (more)

Chiu, Wan Hang Melanie

2012-01-01T23:59:59.000Z

314

Electron-beam induced electric-hydraulic expansion in a silica-shelled gallium microball-nanotube structure  

Science Conference Proceedings (OSTI)

Heteroshape-heteroscale structure of silica-shelled Ga microball-nanotube was fabricated. Under in situ electron-beam irradiation, an abnormally large and fast expansion of Ga was observed. Failed by a sole routine heating effect of electron-beam, the expansion was explained by an electric-hydraulic expansion effect taking into account a huge inner pressure induced by the repelling Coulomb force of positively charged Ga ions on the Ga microball surface. The ions were accumulated due to knocking-out of Ga electrons under irradiation and shielding effect of a silica shell which prevents the charge balance restoration. A circuit model is proposed to calculate the accumulation of Ga ions.

Gao, Y. H.; Sun, M.; Su, J. [Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology (HUST), LuoyuRoad 1037, Wuhan 430074 (China); Zhi, C. Y.; Golberg, D.; Bando, Y. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Duan, X. F. [Institute of Physics, Beijing National Laboratory of Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-08-22T23:59:59.000Z

315

Silicon-germanium/gallium phosphide material in high power density thermoelectric modules. Final report, February 1980--September 1981  

DOE Green Energy (OSTI)

This is the final report of work on the characterization of an improved Si-Ge alloy and the fabrication of thermoelectric devices. The improved Si-Ge alloy uses a small addition of GaP in n- and p- type 80 at.% Si-20 at.% Ge; this addition reduces the thermal conductivity, thereby increasing its figure of merit and conversion efficiency. The thermoelectric devices fabricated include multicouples intended for use in Radioisotope Thermoelectric Generators (RTGs) and ring-type modules intended for use with nuclear reactor heat sources. This report summarizes the effort in the material as well as the device areas and discusses individual phases of each area. Results should form basis for further effort.

Not Available

1981-12-31T23:59:59.000Z

316

Catalytic Fast Pyrolysis of Biomass in a Bubbling Fluidized Bed Reactor with Gallium Promoted ZSM-5 Catalyst.  

E-Print Network (OSTI)

??The huge energy demand of our society is causing fossil fuel resources to diminish rapidly. Therefore, it is critical to search for alternative energy resources.… (more)

Shi, Jian

2012-01-01T23:59:59.000Z

317

Comparative band alignment of plasma-enhanced atomic layer deposited high-k dielectrics on gallium nitride  

SciTech Connect

Al{sub 2}O{sub 3} films, HfO{sub 2} films, and HfO{sub 2}/Al{sub 2}O{sub 3} stacked structures were deposited on n-type, Ga-face, GaN wafers using plasma-enhanced atomic layer deposition (PEALD). The wafers were first treated with a wet-chemical clean to remove organics and an in-situ combined H{sub 2}/N{sub 2} plasma at 650 Degree-Sign C to remove residual carbon contamination, resulting in a clean, oxygen-terminated surface. This cleaning process produced slightly upward band bending of 0.1 eV. Additional 650 Degree-Sign C annealing after plasma cleaning increased the upward band bending by 0.2 eV. After the initial clean, high-k oxide films were deposited using oxygen PEALD at 140 Degree-Sign C. The valence band and conduction band offsets (VBOs and CBOs) of the Al{sub 2}O{sub 3}/GaN and HfO{sub 2}/GaN structures were deduced from in-situ x-ray and ultraviolet photoemission spectroscopy (XPS and UPS). The valence band offsets were determined to be 1.8 and 1.4 eV, while the deduced conduction band offsets were 1.3 and 1.0 eV, respectively. These values are compared with the theoretical calculations based on the electron affinity model and charge neutrality level model. Moreover, subsequent annealing had little effect on these offsets; however, the GaN band bending did change depending on the annealing and processing. An Al{sub 2}O{sub 3} layer was investigated as an interfacial passivation layer (IPL), which, as results suggest, may lead to improved stability, performance, and reliability of HfO{sub 2}/IPL/GaN structures. The VBOs were {approx}0.1 and 1.3 eV, while the deduced CBOs were 0.6 and 1.1 eV for HfO{sub 2} with respect to Al{sub 2}O{sub 3} and GaN, respectively.

Yang Jialing; Eller, Brianna S.; Zhu Chiyu; England, Chris; Nemanich, Robert J. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)

2012-09-01T23:59:59.000Z

318

On the Mass Eigenstate Composition of the 8B Neutrinos from the Sun  

E-Print Network (OSTI)

The present data of gallium experiments provide indirectly the only experimental limit on the fraction of $\

A. Kopylov; V. Petukhov

2006-08-14T23:59:59.000Z

319

Photoluminescence study of GaAs films on Si(100) grown by atomic hydrogen-assisted molecular beam epitaxy  

Science Conference Proceedings (OSTI)

Keywords: atomic hydrogen-mediated epitaxy, lattice-mismatched heteroepitaxy, minority carrier lifetime, molecular beam epitaxy, photoluminescence decay, solar cells

Yoshitaka Okada; Shigeru Ohta; Akio Kawabata; Hirofumi Shimomura; Mitsuo Kawabe

1994-03-01T23:59:59.000Z

320

J1, MBE Growth of Metamorphic InGaP on GaAs and GaP for Wide ...  

Science Conference Proceedings (OSTI)

I4, Electrical Spin Injection in a Hybrid Organic/Inorganic Spin-Polarized Light Emitting Diode (Spin-LED) · I5, Properties of MnAs/GaMnAs/MnAs Magnetic ...

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Efficiency-improvement study for GaAs solar cells. Final report, March 31, 1980-September 30, 1981  

DOE Green Energy (OSTI)

High-yield fabrication of good quality AlGaAs/GaAs concentration solar cells has been a limiting factor in widespread utilization of these high conversion efficiency (22 to 24%) photovoltaic cells. Reported is a series of investigations to correlate solar cell yield with substrate quality, growth techniques, layer composition, and metallization processes. In addition, several diagnostic techniques are described to aid in device characterization.

Cape, J.A.; Oliver, J.R.; Zehr, S.W.

1982-04-01T23:59:59.000Z

322

Ammothermal Growth of Gan Substrates For Leds: High-Pressure Ammonothermal Process for Bulk Gallium Nitride Crystal Growth for Energy Efficient Commercially Competitive Lighting  

Science Conference Proceedings (OSTI)

Broad Funding Opportunity Announcement Project: The new GaN crystal growth method is adapted from that used to grow quartz crystals, which are very inexpensive and represent the second-largest market for single crystals for electronic applications (after silicon). More extreme conditions are required to grow GaN crystals and therefore a new type of chemical growth chamber was invented that is suitable for large-scale manufacturing. A new process was developed that grows GaN crystals at a rate that is more than double that of current processes. The new technology will enable GaN substrates with best-in-world quality at lowest-in-world prices, which in turn will enable new generations of white LEDs, lasers for full-color displays, and high-performance power electronics.

None

2011-01-01T23:59:59.000Z

323

Structural TEM study of nonpolar a-plane gallium nitride grown on (112_0) 4H-SiC by organometallic vapor phase epitaxy  

E-Print Network (OSTI)

nitride grown on (1120) 4H-SiC by organometallic vapor phasea-plane GaN grown on a 4H-SiC substrate with an AlN buffergrown on (0001) Al 2 O 3 , 6H-SiC or free- standing GaN

Zakharov, Dmitri N.; Liliental-Weber, Zuzanna; Wagner, Brian; Reitmeier, Zachary J.; Preble, Edward A.; Davis, Robert F.

2005-01-01T23:59:59.000Z

324

Indium-Gallium Segregation in CuIn$_{x}$Ga$_{1-x}$Se$_2$: An ab initio based Monte Carlo Study  

E-Print Network (OSTI)

Thin-film solar cells with CuIn$_x$Ga$_{1-x}$Se$_2$ (CIGS) absorber are still far below their efficiency limit, although lab cells reach already 19.9%. One important aspect is the homogeneity of the alloy. Large-scale simulations combining Monte Carlo and density functional calculations show that two phases coexist in thermal equilibrium below room temperature. Only at higher temperatures, CIGS becomes more and more a homogeneous alloy. A larger degree of inhomogeneity for Ga-rich CIGS persists over a wide temperature range, which may contribute to the low observed efficiency of Ga-rich CIGS solar cells.

Ludwig, Christian D R; Felser, Claudia; Schilling, Tanja; Windeln, Johannes; Kratzer, Peter

2010-01-01T23:59:59.000Z

325

Calculation of oxygen diffusion in plutonium oxide films during the high-temperature oxidation of plutonium-1 weight percent gallium in 500 torr of air  

Science Conference Proceedings (OSTI)

Oxygen self-diffusion in PuO/sub 1.995/ was calculated from rate constants obtained for the parabolic oxidation of the Pu-1 wt % Ga alloy in 500-torr dry air between 250 and 480/degree/C. The activation energy for oxygen vacancy diffusion in the n-type PuO/sub 2-x/ is 22.6 kcal/mole. Results from this investigation are compared with other reported results, and possible explanation for the difference in results is discussed. 21 refs., 5 figs., 1 tab.

Stakebake, J.L.

1988-05-27T23:59:59.000Z

326

Atomic-level cotrol of the thermoelectric properties in polytypoid nanowires  

E-Print Network (OSTI)

an alloy of indium and gallium oxide. In the IGZO nanowireof 500-900 K for bulk indium zinc oxide (IZO, In 2 O 3 (ZnO)nanowires IZO and indium gallium zinc oxide (IGZO, In 2-x Ga

C.Andrews, Sean

2013-01-01T23:59:59.000Z

327

In This Issue:  

Science Conference Proceedings (OSTI)

... each sample showed enrichment to approximately ... variations in commercial high-purity gallium ... Reference Materials: Uranium isotopic standard ref ...

2003-09-24T23:59:59.000Z

328

Available Technologies - Lawrence Berkeley National Laboratory  

Advanced Materials; Biofuels; ... alternative semiconductor materials to be ... (copper indium gallium selenide) have potential, but their raw material sources are ...

329

LATE NEWS: KK3, Non-Catalytic Synthesis of GaN Nanostructures ...  

Science Conference Proceedings (OSTI)

We have observed the synthesis of gallium nitride (GaN) nanopowders on boron ... as 400°C. The synthesis process is based on the reaction between gallium atoms from the decomposition of gallium acetylacetonate and ammonia gas molecules. ... the crystal structure and growth mechanism of the grown nanostructures.

330

Publications from Research Conducted at FIE-TAX | ORNL Neutron...  

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

Thaler A., Ni N., Canfield P. C., McQueeney R. J., Schmalian J., Goldman A. I., "Unconventional pairing in the iron arsenide superconductors", Physical Review B 81, 140501...

331

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

E-Print Network (OSTI)

and these unusual behaviors open new applications including large-gain, low-threshold quan- tum lasers, light-emitting diodes, single-electron transistors, and so on. A number of different techniques have been de- veloped

Heaton, Thomas H.

332

AlGaAsSb buffer/barrier on GaAs substrate for InAs channel devices with high electron mobility and practical reliability  

Science Conference Proceedings (OSTI)

Keywords: AlGaAsSb, Hall elements, InAs, Sb, buffer/barriers, deep quantum well, field effect transistors, reliability

S. Miya; S. Muramatsu; N. Kuze; K. Nagase; T. Iwabuchi; A. Ichii; M. Ozaki; I. Shibasaki

1996-03-01T23:59:59.000Z

333

Glossary of Terms - Sandia National Laboratories  

A management representation letter is required by General Accepted Auditing Standards (GAAS) and General Accepted Government Auditing Standards (GAGAS).

334

Collaborative Technologies for Distributed Science - Fusion Energy and High-Energy Physics (A25539)  

E-Print Network (OSTI)

General Atomics Report GA-A25539 (2006)24th Symposium on Fusion Technology Warsaw, pl, 2006999613320

Schissel, D.P.

2006-08-24T23:59:59.000Z

335

Structural tuning of residual conductivity in highly mismatched III-V layers  

DOE Patents (OSTI)

A new process to control the electrical conductivity of gallium nitride layers grown on a sapphire substrate has been developed. This process is based on initially coating the sapphire substrate with a thin layer of aluminum nitride, then depositing the gallium nitride thereon. This process allows one to controllably produce gallium nitride layers with resistivity varying over as much as 10 orders of magnitude, without requiring the introduction and activation of suitable dopants.

Han, Jung (Albuquerque, NM); Figiel, Jeffrey J. (Albuquerque, NM)

2002-01-01T23:59:59.000Z

336

Solar Photovoltaic Technologies - Energy Innovation Portal  

From 2002 to 2007 the market for Copper Indium Gallium Selenide ... According to the U.S. Energy Information Administration’s 2010 International Energy Outlook, ...

337

THERMODYNAMICS OF SOLID AND LIQUID GROUP III-V ALLOYS  

E-Print Network (OSTI)

temperature anomalous heat capacities,(! ) a maximum in theestimated high-temperature heat capacity of gallium ratherfrom low temperature heat capacity measurements. The

Anderson, T.J.

2011-01-01T23:59:59.000Z

338

NREL: Process Development and Integration Laboratory - Copper Indium  

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

Copper Indium Gallium Diselenide Cluster Tool Capabilities Copper Indium Gallium Diselenide Cluster Tool Capabilities The Copper Indium Gallium Diselenide (CIGS) cluster tool in the Process Development and Integration Laboratory offers powerful capabilities with integrated chambers for depositing, processing, measuring, and characterizing photovoltaic materials and devices. You can read more on the rationale for developing this cluster tool and its capabilities, and check out the National Solar Technology Roadmap for CIGS Photovoltaics. Contact Miguel Contreras for more details on these capabilities. The Copper Indium Gallium Diselenide cluster tool, manufactured by DCA Instruments, will be operational in 2009. Techniques will include evaporation; radiofrequency, direct-current (DC), and pulsed DC sputtering;

339

NIST Manuscript Publication Search  

Science Conference Proceedings (OSTI)

... Abstract: Although the efficiency of the Gallium Nitride (GaN) Light Emitting-Diode (LED) has improved in the past decade, a great opportunity ...

2013-12-19T23:59:59.000Z

340

Development of a Bulk GaN Growth Technique for Low Defect Density...  

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

Enabling Next-Generation Power Electronics: Electrochemical Solution Growth (ESG) Technique for Bulk Gallium Nitride Substrates Karen Waldrip Dept. 2546, Advanced Power Sources R&D...

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Index of Semiconductor Process Gases  

Science Conference Proceedings (OSTI)

... Hydrogen Bromide, HBr. Vinyl Fluoride. C 2 H 3 F. Hydrogen Chloride, HCl. Vinyl Chloride. C 2 H 3 Cl. Hydrogen Fluoride, HF. Trimethyl Gallium. ...

2012-07-27T23:59:59.000Z

342

NIST: Marie Curie and the NBS Radium Standards ...  

Science Conference Proceedings (OSTI)

... 1908, he received his Doctorate in Physics from Imperial ... of the radioisotope gallium-67 (Physical Review 54 ... which is still in use in nuclear medicine ...

2010-10-05T23:59:59.000Z

343

Nonoxide Fluorescent Nanoparticles - Oak Ridge National Laboratory  

for the U.S. Department of Energy Presentation_name ... y of the dopanmatert – Gallium – Indium ... Bloo Solar; EPOD Solar. AQT; Canrom. New Solar Ventures;

344

at-meeting technical program in .pdf format  

Science Conference Proceedings (OSTI)

Jun 24, 1998 ... trical Engr., Walter Scott Engr. Center, Lincoln, NE 68588-0511 USA; ...... Radiative Efficiency of High Quality Gallium Nitride Thin Films: Peter.

345

--No Title--  

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

the Reactor and Gallium Anomalies with intense (anti)neutrino emitters Thierry Lasserre (CEA) Abstract: Several observed anomalies in neutrino oscillation data can be explained by...

346

NETL: NEPA Categorical Exclusions - January 2010 to March 2010  

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

EEProject Management Center Y 352010 Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices Applied Materials, Inc. Santa Clara, CA EEBETD Y 352010 Red Birch...

347

Solid-State Lighting: 2012 Solid-State Lighting Manufacturing...  

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

Frank Cerio, Veeco Instruments Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices Vivek Agrawal, Applied Materials Driving Down HB-LED Costs:...

348

Solid-State Lighting Issue 28: Scientific Literature (Mid May...  

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

National University of Kaohsiung (Taiwan): "Wavelength shift of gallium nitride light emitting diode with p-down structure." W.H. Lan, IEEE Transactions on Electron Devices,...

349

List of common materials available for ESTAR  

Science Conference Proceedings (OSTI)

... 20 Calcium 21 Scandium 22 Titanium 23 Vanadium 24 Chromium 25 Manganese 26 Iron 27 Cobalt 28 Nickel 29 Copper 30 Zinc 31 Gallium 32 ...

350

NIST: Basic Atomic Spectroscopic Data - Atomic Number  

Science Conference Proceedings (OSTI)

... 20 Calcium 21 Scandium 22 Titanium 23 Vanadium 24 Chromium 25 Manganese 26 Iron 27 Cobalt 28 Nickel 29 Copper 30 Zinc 31 Gallium 32 ...

351

It's Elemental - The Element Germanium  

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

is in the semiconductor industry. When doped with small amounts of arsenic, gallium, indium, antimony or phosphorus, germanium is used to make transistors for use in...

352

Journal of Research Volume 15  

Science Conference Proceedings (OSTI)

... Atomic weight of gallium, p. 409 Lundell, GEF; Hoffman, JI http://dx ... Design and construction of an experimental diffusion battery, p. 441 Proffitt, MJ ...

2012-10-04T23:59:59.000Z

353

Visit the National Academies Press online, the authoritative ...  

Science Conference Proceedings (OSTI)

... of the US electricity generation, and oil prices should not ... swings and a poor heating, ventilating, and air ... to gallium nitride growth is “home-built,” and ...

2012-09-27T23:59:59.000Z

354

Solibro AB | Open Energy Information  

Open Energy Info (EERE)

search Name Solibro AB Place Uppsala, Sweden Zip 751 21 Sector Solar Product Develops thin film solar cells using copper indium gallium diselenide (CIGS). References Solibro...

355

Applied Quantum Technology AQT | Open Energy Information  

Open Energy Info (EERE)

AQT Jump to: navigation, search Name Applied Quantum Technology (AQT) Place Santa Clara, California Zip 95054 Product California-based manufacturer of CIGS (copper indium gallium...

356

Categorical Exclusion Determinations: American Recovery and Reinvestme...  

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

Exclusion Determination Transphorm, Inc. -High Performance Gallium Nitride High Electron Mobility Transistor Modules for Agile Power Electronics CX(s) Applied: B3.6 Date:...

357

Page not found | Department of Energy  

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

Exclusion Determination Transphorm, Inc. -High Performance Gallium Nitride High Electron Mobility Transistor Modules for Agile Power Electronics CX(s) Applied: B3.6 Date:...

359

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

360

Evidence for three-dimensional Fermi-surface topology of the layered electron-doped iron superconductor Ba(Fe1 xCox)2As2  

SciTech Connect

The electronic structure of electron doped iron-arsenide superconductors Ba(Fe{sub 1-x}Co{sub x}){sub 2}As{sub 2} has been measured with Angle Resolved Photoemission Spectroscopy. The data reveal a marked photon energy dependence of points in momentum space where the bands cross the Fermi energy, a distinctive and direct signature of three-dimensionality in the Fermi surface topology. By providing a unique example of high temperature superconductivity hosted in layered compounds with three-dimensional electronic structure, these findings suggest that the iron-arsenides are unique materials, quite different from the cuprates high temperature superconductors.

Vilmercati, P. [University of Tennessee, Knoxville (UTK); Fedorov, A. V. [Lawrence Berkeley National Laboratory (LBNL); Vobornik, I. [TASC National Laboratory, Trieste, Italy; Manju, U. [TASC National Laboratory, Trieste, Italy; Panaccione, G. [TASC National Laboratory, Trieste, Italy; Goldoni, A. [Sincrotrone Trieste, Basovizza, Italy; Safa-Sefat, Athena [ORNL; McGuire, Michael A [ORNL; Sales, Brian C [ORNL; Jin, Rongying [ORNL; Mandrus, David [ORNL; Singh, David J [ORNL; Mannella, Norman [ORNL

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Luminescence properties of light-emitting diodes based on GaAs with the up-conversion Y{sub 2}O{sub 2}S:Er,Yb luminophor  

SciTech Connect

Y{sub 2}O{sub 2}S luminophors doped with Er{sup 3+} and Yb{sup 3+} ions are produced by means of solid-phase synthesis and deposited onto standard AL123A infrared light-emitting diodes. When excited with 940 nm radiation from a light-emitting diode, the structures exhibit intense visible up-conversion luminescence. A maximal brightness of 2340 cd/m{sup 2} of green and red up-conversion luminescence at corresponding wavelengths around 550 and 600 nm is observed for the Y{sub 2}O{sub 2}S compound doped with 2 at % Er{sup 3+} ions and 6 at % Yb{sup 3+} ions. The ratio of the intensity of green (or red) up-conversion luminescence to the intensity of infrared Stokes luminescence increases with increasing applied voltage. The efficiency of visible emission of the light-emitting diode structures is {eta} = 1.2 lm/W at an applied voltage of 1.5 V.

Gruzintsev, A. N., E-mail: gran@ipmt-hpm.ac.ru [Russian Academy of Sciences, Institute of Problems of Microelectronics Technology (Russian Federation); Barthou, C.; Benalloul, P. [Institute des NanoSciences (France)

2008-03-15T23:59:59.000Z

362

Preparation of CIGS-based solar cells using a buffered electrodeposition bath  

DOE Patents (OSTI)

A photovoltaic cell exhibiting an overall conversion efficiency of at least 9.0% is prepared from a copper-indium-gallium-diselenide thin film. The thin film is prepared by simultaneously electroplating copper, indium, gallium, and selenium onto a substrate using a buffered electro-deposition bath. The electrodeposition is followed by adding indium to adjust the final stoichiometry of the thin film.

Bhattacharya, Raghu Nath (Littleton, CO)

2007-11-20T23:59:59.000Z

363

I'm happy to report that The Earth Observer is beginning its 20th year as a NASA publication. The first issue  

E-Print Network (OSTI)

arsenide GHG greenhouse gas GHP geothermal heat pump GSA General Services Administration GSHP ground source heat pump GS-IHP ground source integrated heat pump GUI graphical user interface GW gigawatt GWh Reliability and Security TES thermal energy storage TM3PS Tactical Modular Mobile Microgrid Power Systems TPD

364

Impact of elliptical cross-section on the propagation delay of multi-channel gate-all-around MOSFET based inverters  

Science Conference Proceedings (OSTI)

Multi-channel (MC) gate-all-around (GAA) metal-oxide-semiconductor field-effect transistor (MOSFET) is one of the promising candidates for the next-generation high performance devices. However, due to fabrication imperfections the cross-section of GAA ... Keywords: Effective diameter, Gate-all-around (GAA), Metal-oxide-semiconductor field-effect transistor (MOSFET), Multi-channel, Propagation delay, Scaling

Subindu Kumar, Shankaranand Jha

2013-09-01T23:59:59.000Z

365

Profiling the Built-In Electrical Potential in III-V Multijunction Solar Cells (Poster)  

DOE Green Energy (OSTI)

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

366

NIST Terahertz Reflection Measurements  

Science Conference Proceedings (OSTI)

... b) Superimposed Fourier Transform amplitude and power reflection map ... laser for broadband (0.2-2.5) THz GaAs antenna generation and detection ...

2013-04-01T23:59:59.000Z

367

NIST Steven Brown  

Science Conference Proceedings (OSTI)

... Award for "Electron and nuclear spin interactions ... single GaAs quantum dots," Physical Review Letters ... Ph.D. Applied Physics, University of Michigan ...

2011-10-11T23:59:59.000Z

368

JEM Abstracts: May 1997  

Science Conference Proceedings (OSTI)

They enable conversion of electrical energy to mechanical energy, they underlie ... Direct Etching of GaAs Using Chlorofluorocarbon (CFC) Alternative Gases

369

Poster Session - Programmaster.org  

Science Conference Proceedings (OSTI)

Feb 14, 2010... such as electrical short circuit or debris for equipment manufacturers and .... Reliability test vehicles comprise a GaAs chip which was flip chip ...

370

Technical Program, Thursday Morning Sessions  

Science Conference Proceedings (OSTI)

Step-Free InAs Quantum Well Selectively Grown on GaAs (111)B Substrate: ... Jonas Johansson, Lars Samuelson and Werner Seifert, Solid State Physics, Lund  ...

371

Accelerating Scientific Discovery Through Computation and ...  

Science Conference Proceedings (OSTI)

... electronic structure of GaAs nanocrystals, inclu- sion of ... lowest hole state in a CdS nano- crystal. ... well region of a nanoheterostructured nanocrystal. ...

2009-09-08T23:59:59.000Z

372

Solar Photovoltaics Research and Technology: The Revolution ...  

Science Conference Proceedings (OSTI)

Moreover, technology progress and ownership for next-generation solar PV mandates a ... Dislocations in Si-Doped LEC GaAs Revisited: A Spectrum Image

373

Project Summaries  

Science Conference Proceedings (OSTI)

... this will increase productive utilization of the Raritan cluster to close to 100%. ... on a substrate of GaAs results in formation of mounds, rather than ...

2006-02-06T23:59:59.000Z

374

JEM Abstracts: January 1995  

Science Conference Proceedings (OSTI)

... arsenic stabilized growth of GaAs resulted in low mobility, p-type material. ... Electron Irradiation Induced Defects and Schottky Diode Characteristics for ...

375

JEM Abstracts: April 1995  

Science Conference Proceedings (OSTI)

Selected area electron diffraction (SAD) patterns at the interface confirmed that ..... Mobility of Modulation Doped AlGaAs/Low-Temperature MBE-Grown GaAs ...

376

Method of making V.sub.3 Ga superconductors  

DOE Patents (OSTI)

An improved method for producing a vanadium-gallium superconductor wire having aluminum as a component thereof is disclosed, said wire being encased in a gallium bearing copper sheath. The superconductors disclosed herein may be fabricated under normal atmospheres and room temperatures by forming a tubular shaped billet having a core composed of an alloy of vanadium and aluminum and an outer sheath composed of an alloy of copper, gallium and aluminum. Thereafter the entire billet is swage reduced to form a wire therefrom and heat treated to form a layer of V.sub.3 Ga in the interior of the wire.

Dew-Hughes, David (Bellport, NY)

1980-01-01T23:59:59.000Z

377

Ultrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz radiation  

E-Print Network (OSTI)

and injection currents have been generated in bulk GaAs and strained GaAs quantum wells QWs , respectivelyUltrafast shift and injection currents observed in wurtzite semiconductors via emitted terahertz; published online 18 November 2005 Shift and injection currents are generated in the wurtzite semiconductors

Van Driel, Henry M.

378

The MOCVD Growth Technique  

Science Conference Proceedings (OSTI)

...can be expressed as: (C 2 H 5 ) 3 Ga + AsH 3 â?? GaAs + 3C 2 H 6 (Eq 23) (CH 3 ) 3 Ga + AsH 3 â?? GaAs + 3CH 4 (Eq 24) The

379

The effects of quantum dot coverage in InAs/(In)GaAs nanostructures for long wavelength emission  

Science Conference Proceedings (OSTI)

We present a study on the effects of quantum dot coverage on the properties of InAs dots embedded in GaAs and in metamorphic In0.15Ga0.85As confining layers grown by molecular beam epitaxy on GaAs substrates. We show that redshifted ... Keywords: Long wavelength emission, Molecular beam epitaxy, Quantum dot ripening, Quantum dots

G. Trevisi; L. Seravalli; P. Frigeri; M. Prezioso; J. C. Rimada; E. Gombia; R. Mosca; L. Nasi; C. Bocchi; S. Franchi

2009-03-01T23:59:59.000Z

380

Defect gap states on III-V semiconductor-oxide interfaces (invited)  

Science Conference Proceedings (OSTI)

Interfaces models of (100)GaAs and various high K oxides such as HfO"2, Gd"2O"3 or Al"2O"3 are used to study the interfacial defects and mis-bonded sites which can introduce states into the semiconductor gap, and cause the Fermi level pinning observed ... Keywords: Calculation, FET, GaAs, Interface states, Oxide, Passivation

J. Robertson; L. Lin

2011-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Comparison of quantum confinement effects between quantum wires and dots  

E-Print Network (OSTI)

? wire . Si GaAs InAs InP CdSe CdS CdTe ? dot ? dot ? wire ?systems like InP and CdSe. Here, we like to address thesematerials: Si, InP, InAs, GaAs, CdSe, CdS, and CdTe. Unlike

Li, Jingbo; Wang, Lin-Wang

2004-01-01T23:59:59.000Z

382

Design of a wideband multi-standard antenna switch for wireless communication devices  

Science Conference Proceedings (OSTI)

A wideband Low Power Single Pole 6-Throw (SP6T) antenna switch has been designed for GSM/DCS/802.11b mobile standards using a newly improved architecture and fabricated using a pseudomorphic depletion mode 0.18@mm HEMT GaAs process. The switch exhibits ... Keywords: Antenna switch, GaAs, MMIC, Mobile telecommunications, Wideband, pHEMT transistors

Vlad Marian; Jacques Verdier; Bruno Allard; Christian Vollaire

2011-05-01T23:59:59.000Z

383

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

384

Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology. Annual subcontract report, 1 August 1991--31 July 1992  

DOE Green Energy (OSTI)

This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, {approximately} 1 {times} 10{sup 5} cm{sup {minus}5}, as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 {times}10{sup 7} cm{sup {minus}2}. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

Vernon, S.M. [Spire Corp., Bedford, MA (United States)

1993-04-01T23:59:59.000Z

385

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

386

Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology  

DOE Green Energy (OSTI)

This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, [approximately] 1 [times] 10[sup 5] cm[sup [minus]5], as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 [times]10[sup 7] cm[sup [minus]2]. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

Vernon, S.M. (Spire Corp., Bedford, MA (United States))

1993-04-01T23:59:59.000Z

387

Page not found | Department of Energy  

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

Categorical Exclusion Determination Advanced Epi Tools for Gallium Nitride LED (Light Emitting Diode) Devices CX(s) Applied: B3.6 Date: 03052010 Location(s): Santa Clara,...

388

CX-010974: Categorical Exclusion Determination | Department of...  

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

CX-010974: Categorical Exclusion Determination Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle...

389

Power Electronics Reliability Kick Off Meeting ? Silicon Power...  

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

failure modes of post-silicon power electronic (PE) devices such as silicon carbide (SiC) and gallium nitride (GaN) switches. * Seek opportunities for condition monitoring (CM)...

390

CX-010973: Categorical Exclusion Determination | Department of...  

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

CX-010973: Categorical Exclusion Determination Advanced Low-Cost Silicon Carbide (SiC) and Gallium Nitride (GaN) Wide Bandgap Inverters for Under-the-Hood Electric Vehicle...

391

Long-Term Performance Data and Analysis of CIS/CIGS Modules Deployed Outdoors (Presentation)  

DOE Green Energy (OSTI)

The long-term performance data of copper indium diselenide (CIS) and gallium-alloyed CIS (CIGS) photovoltaic (PV) modules are investigated to assess the reliability of this technology.

del Cueto, J. A.; Kroposki, B.; Rummel, S.; Anderberg, A.

2008-08-10T23:59:59.000Z

392

Embedded Atom Method for studying shock processes in materials ...  

Science Conference Proceedings (OSTI)

A brief overview of a shock-induced phase transition in gallium will be presented showing the discovery of a meta-stable phase prior to shock melting will be ...

393

CX-001137: Categorical Exclusion Determination | Department of...  

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

Categorical Exclusion Determination Advanced Epi Tools for Gallium Nitride LED (Light Emitting Diode) Devices CX(s) Applied: B3.6 Date: 03052010 Location(s): Santa Clara,...

394

Categorical Exclusion Determinations: National Energy Technology...  

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

Categorical Exclusion Determination Advanced Epi Tools for Gallium Nitride LED (Light Emitting Diode) Devices CX(s) Applied: B3.6 Date: 03052010 Location(s): Santa Clara,...

395

Barrier Coatings for Thin Film Solar Cells: Final Subcontract Report, September 1, 2002 -- January 30, 2008  

DOE Green Energy (OSTI)

This program has involved investigations of the stability of CdTe and copper-indium-gallium-diselenide (CIGS) solar cells under damp heat conditions and effects of barrier coatings.

Olsen, L. C.

2010-03-01T23:59:59.000Z

396

NETL F 451.1-1/1 Categorical Exclusion (CX) Designation Form  

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

01042010 - 12312011 Santa Clara, Ca Advanced Epi Tools for Gallium Nitride Light Emitting Diode Devices To develop a multi-chamber system such as a two MOCVD chambers, one...

397

Slide 1  

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

University Ph.D. Thesis by Peter Eschbach, "Investigation of Buffer Layers in Copper Indium Gallium Selenium Solar Cells" (2002) 50 52 54 56 58 60 62 64 66 Binding Energy (eV)...

398

Research Highlights | ORNL Neutron Sciences  

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

on structural properties of new materials, brought a sample from the solid solution of indium-gallium-magnesium-oxide (i.e., InGaCu0.60Mg0.40O4) to the workshop. "The...

399

Semiconductor Nanowires and Nanotubes for Energy Conversion  

E-Print Network (OSTI)

an alloy of indium and gallium oxide. In the IGZO nanowireprecipitation of indium in zinc oxide. Journal of PhysicsO 3 (ZnO) n ), and indium iron zinc oxide (IFZO, In 2-x Fe x

Fardy, Melissa Anne

2010-01-01T23:59:59.000Z

400

Nanocrystal Photovoltaics: The Case of Cu2S-CdS  

E-Print Network (OSTI)

solid was gallium- or indium- oxide because the EGaIn wasCdS Microarrays on Indium Tin Oxide Substrates Appliedpole figure ITO - indium tin oxide RMS – root mean square

Rivest, Jessica Louis Baker

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Wrapping process for fabrication of A-15 superconducting composite wires  

DOE Patents (OSTI)

A method for fabricating superconducting wires wherein a billet of copper containing filaments of niobium or vanadium is rolled to form a strip which is wrapped about a tin-alloy core to form a composite. The alloy is a tin-copper alloy for niobium filaments and a gallium-copper alloy for vanadium filaments. The composite is then drawn down to a desired wire size and heat treated. During the heat treatment process, the tin in the bronze reacts with the niobium to form the superconductor niobium tin. In the case where vanadium is used, the gallium in the gallium bronze reacts with the vanadium to form the superconductor vanadium gallium. This new process eliminates the costly annealing steps, external tin plating and drilling of bronze ingots required in a number of prior art processes.

Suenaga, M.; Klamut, C.J.; Luhman, T.S.

1980-08-15T23:59:59.000Z

402

Alternative Energy Technologies Solar Power  

E-Print Network (OSTI)

(LCDs), flat panel displays, optical coatings, light-emitting diodes (LEDs) antistatic coatings, strain gauges, gas sensors. Light-emitting diodes (LED's) Power amplifiers for cell phones Indium Gallium #12

Scott, Christopher

403

JEM Table of Contents: November 1995 - TMS  

Science Conference Proceedings (OSTI)

Doping of Gallium Nitride Using Disilane [pp. 1547-1550] A.E. Wickenden, L.B. Rowland, K. Doverspike, D.K. Gaskill, J.A. Freitas, Jr., D.S. Simons, and P.H. Chi.

404

PTIP Ltd | Open Energy Information  

Open Energy Info (EERE)

Ltd Jump to: navigation, search Name PTIP Ltd Place South Africa Sector Solar Product Thin-film Copper-indium-gallium-sulphur-selenide solar cell technology spinout from the...

405

Nuvosun Inc | Open Energy Information  

Open Energy Info (EERE)

Zip 94303-4601 Product California-based copper indium gallium (di)selenide (CIGS) thin film PV maker. References Nuvosun Inc1 LinkedIn Connections CrunchBase Profile No...

406

MOCVD growth of In GaP-based heterostructures for light emitting devices  

E-Print Network (OSTI)

In this work, we examine fundamental materials processes in the growth of indium gallium phosphide (InGaP) via metalorganic chemical vapor deposition (MOCVD). In particular, we realize improvements in the epitaxial integration ...

McGill, Lisa Megan, 1975-

2004-01-01T23:59:59.000Z

407

Long-Term Performance Data and Analysis of CIS/CIGS Modules Deployed Outdoors  

DOE Green Energy (OSTI)

The long-term performance data of copper indium diselenide (CIS) and gallium-alloyed CIS (CIGS) photovoltaic (PV) modules are investigated to assess the reliability of this technology.

del Cueto, J.A.; Rummel, S.; Kroposki, B.; Anderberg, A.

2008-11-01T23:59:59.000Z

408

Page not found | Department of Energy  

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

-High Performance Gallium Nitride High Electron Mobility Transistor Modules for Agile Power Electronics CX(s) Applied: B3.6 Date: 08052010 Location(s): California Office(s):...

409

Amorphous silicon/polycrystalline thin film solar cells  

DOE Patents (OSTI)

An improved photovoltaic solar cell is described including a p-type amorphous silicon layer, intrinsic amorphous silicon, and an n-type polycrystalline semiconductor such as cadmium sulfide, cadmium zinc sulfide, zinc selenide, gallium phosphide, and gallium nitride. The polycrystalline semiconductor has an energy bandgap greater than that of the amorphous silicon. The solar cell can be provided as a single-junction device or a multijunction device.

Ullal, H.S.

1991-03-13T23:59:59.000Z

410

Sulfide-Driven Arsenic Mobilization from Arsenopyrite and Black Shale Pyrite  

Science Conference Proceedings (OSTI)

We examined the hypothesis that sulfide drives arsenic mobilization from pyritic black shale by a sulfide-arsenide exchange and oxidation reaction in which sulfide replaces arsenic in arsenopyrite forming pyrite, and arsenide (As-1) is concurrently oxidized to soluble arsenite (As+3). This hypothesis was tested in a series of sulfide-arsenide exchange experiments with arsenopyrite (FeAsS), homogenized black shale from the Newark Basin (Lockatong formation), and pyrite isolated from Newark Basin black shale incubated under oxic (21% O2), hypoxic (2% O2, 98% N2), and anoxic (5% H2, 95% N2) conditions. The oxidation state of arsenic in Newark Basin black shale pyrite was determined using X-ray absorption-near edge structure spectroscopy (XANES). Incubation results show that sulfide (1 mM initial concentration) increases arsenic mobilization to the dissolved phase from all three solids under oxic and hypoxic, but not anoxic conditions. Indeed under oxic and hypoxic conditions, the presence of sulfide resulted in the mobilization in 48 h of 13-16 times more arsenic from arsenopyrite and 6-11 times more arsenic from isolated black shale pyrite than in sulfide-free controls. XANES results show that arsenic in Newark Basin black shale pyrite has the same oxidation state as that in FeAsS (-1) and thus extend the sulfide-arsenide exchange mechanism of arsenic mobilization to sedimentary rock, black shale pyrite. Biologically active incubations of whole black shale and its resident microorganisms under sulfate reducing conditions resulted in sevenfold higher mobilization of soluble arsenic than sterile controls. Taken together, our results indicate that sulfide-driven arsenic mobilization would be most important under conditions of redox disequilibrium, such as when sulfate-reducing bacteria release sulfide into oxic groundwater, and that microbial sulfide production is expected to enhance arsenic mobilization in sedimentary rock aquifers with major pyrite-bearing, black shale formations.

Zhu, W.; Young, L; Yee, N; Serfes, M; Rhine, E; Reinfelder, J

2008-01-01T23:59:59.000Z

411

Final Technical Report of project: "Contactless Real-Time Monitoring of Paper Mechanical Behavior During Papermaking"  

SciTech Connect

The early precursors of laser ultrasonics on paper were Prof. Y. Berthelot from the Georgia Institute of Technology/Mechanical Engineering department, and Prof. P. Brodeur from the Institute of Paper Science and Technology, both located in Atlanta, Georgia. The first Ph.D. thesis that shed quite some light on the topic, but also left some questions unanswered, was completed by Mont A. Johnson in 1996. Mont Johnson was Prof. Berthelot's student at Georgia Tech. In 1997 P. Brodeur proposed a project involving himself, Y. Berthelot, Dr. Ken Telschow and Mr. Vance Deason from INL, Honeywell-Measurex and Dr. Rick Russo from LBNL. The first time the proposal was not accepted and P. Brodeur decided to re-propose it without the involvement from LBNL. Rick Russo proposed a separate project on the same topic on his side. Both proposals were finally accepted and work started in the fall of 1997 on the two projects. Early on, the biggest challenge was to find an optical detection method which could detect laser-induced displacements of the web surface that are of the order of .1 micron in the ultrasonic range. This was to be done while the web was having an out-of-plane amplitude of motion in the mm range due to web flutter; while moving at 10 m/s to 30 m/s in the plane of the web, on the paper machine. Both teams grappled with the same problems and tried similar methods in some cases, but came up with two similar but different solutions one year later. The IPST, GT, INL team found that an interferometer made by Lasson Technologies Inc. using the photo-induced electro-motive force in Gallium Arsenide was able to detect ultrasonic waves up to 12-15 m/s. It also developed in house an interferometer using the Two-Wave Mixing effect in photorefractive crystals that showed good promises for on-line applications, and experimented with a scanning mirror to reduce motion-induced texture noise from the web and improve signal to noise ratio. On its side, LBNL had the idea to combine a commercial Mach-Zehnder interferometer to a spinning mirror synchronized to the web speed, in order to make almost stationary measurements. The method was demonstrated at up to 10 m/s. Both teams developed their own version of a web simulator that was driving a web of paper at 10 m/s or higher. The Department of Energy and members of the Agenda 2020 started to make a push for merging the two projects. This made sense because their topics were really identical but this was not well received by Prof. Brodeur. Finally IPST decided to reassign the direction of the IPST-INL-GT project in the spring of 1999 to Prof. Chuck Habeger so that the two teams could work together. Also at this time, Honeywell-Measurex dropped as a member of the team. It was replaced by ABB Industrial Systems whose engineers had extensive previous experience of working with ultrasonic sensors on paperboard. INL also finished its work on the project as its competencies were partly redundant with LBNL. From the summer of 1999, the IPST-GT and LBNL teams were working together and helped each other often by collaborating and visiting either laboratory when was necessary. Around the beginning of 2000, began an effort at IPST to create an off-line laser-ultrasonics instrument that could perform automated measurements of paper and paperboard's bending stiffness. It was widely known that the mechanical bending tests of paper used for years by the paper industry were very inaccurate and exhibited poor reproducibility; therefore the team needed a new instrument of reference to validate its future on-line results. In 1999-2000, the focus of the on-line instrument was on a pre-industrial demonstration on a pilot coater while reducing the damage to the web caused by the generation laser, below the threshold where it could be visible by the naked eye. During the spring of 2000 Paul Ridgway traveled to IPST and brought with him a redesigned system still using the same Mach-Zehnder interferometer as before, but this time employing an electric motor-driven spinning mirror instead of the previously belt-driven m

Emmanuel Lafond; Paul Ridgway; Ted Jackson; Rick Russo; Ken Telschow; Vance Deason; Yves Berthelot; David Griggs; Xinya Zhang; Gary Baum

2005-08-30T23:59:59.000Z

412

DEDALOS NREL: Cooperative Research and Development Final Report, CRADA Number CRD-07-237  

DOE Green Energy (OSTI)

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

413

ELECTRON-VOLTAIC CELL STUDY  

SciTech Connect

The properties of Si, GaAs, Ge, and possible beta sources were considered, together with radiation damage to the three materials. Additionally, the characteristics of p-n junction cells under beta activity were derived, and the characteristics of GaAs and Si cells were obtained experimentally. The results indicate that a nuclear battery using GaAs or n-p Si cells with Pm/sup 147/ as the source would operate for 5 to 10 yr with very little radiation damage. Cell characteristics for a given source activity were calculated. 66 references. (D.C.W.)

Robison, W.C.; Nelson, M.D.

1963-01-01T23:59:59.000Z

414

Available Technologies: Low Resistance, p-Type Ohmic Contacts ...  

Novel Structured LED and OLED Devices, IB-2230. Co-implantation of Group VI Elements and Nitrogen for the Formation of Non-Alloyed Ohmic Contacts for n-type GaAs, IB ...

415

Lasing characteristics of GaSb/GaAs self-assembled quantum dots embedded in an InGaAs quantum well  

E-Print Network (OSTI)

be applicable to light sources in fiber-optic communication systems.13 However, there have been no reports intriguing optoelectronic device possibilities on GaAs substrates including lasers, detectors, or solar cells

Jalali. Bahram

416

GaAs/AlGaAs nanostructured composites for free-space and integrated optical devices  

E-Print Network (OSTI)

Fainman, "Influence of chlorine on etched sidewalls inFainman, “Influence of chlorine on etched sidewalls inthe RIBE of GaAs with chlorine (Cl 2 ), ion beam sputtering

Tsai, Chia-Ho

2006-01-01T23:59:59.000Z

417

M6, Enhancement of Hole Transport and Carrier Distribution in ...  

Science Conference Proceedings (OSTI)

DD1, Enhanced Spin Injection and Spin Lifetimes in Graphene ... FF5, GaInNAsSb Quantum Wells with Strain-Compensating GaAsP Layers for GaAs-

418

Rotor Scale Model Tests for Power Conversion Unit of GT-MHR (A26845)  

E-Print Network (OSTI)

Proc. Of 5th International Conf. On High Temperatore Reactor Technology, Prague, Czech Republic, 2010; General Atomics Report GA-A26845 (2010)5th International Conference on High Temperature Reactor Technology Prague, CZ, 2010999619072

Baxi, C.B.

2010-08-18T23:59:59.000Z

419

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

420

Comprehensive Measurements and Modeling of SOL and Core Plasma Fueling and Carbon Sources in DIII-D (A25072)  

E-Print Network (OSTI)

Proc. 32nd Euro. Conf. On Plasma Phys., Tarragona, Spain, 2005; General Atomics Report GA-A25072 (2005)32nd EPS Conference on Controlled Fusion and Plasma Physics Tarragona, ES, 2005999610815

Groth, M.

2005-07-06T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Nonlinear Dynamics and Energy Loss Mechanisms of ELMs (A25091)  

E-Print Network (OSTI)

Proc. 32nd Euro. Conf. On Plasma Phys., Tarragona, Spain, 2005; General Atomics Report GA-A25091 (2005)32nd EPS Conference on Controlled Fusion and Plasma Physics Tarragona, ES, 2005999610795

Snyder, P.B.

2005-06-27T23:59:59.000Z

422

Poster Presentations | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

(Smedley-Alkali) .pdf file (455KB) GaAs Detectors (Durbin) .pdf file (2.0MB) Detector R&D @ LBNL (Denes) .pdf file (2.5MB) Advanced Beam Physics @ UCLA (Musumeci) .pdf file...

423

Technical Session II Talks | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Technical Session II Talks Print Text Size: A A A RSS Feeds FeedbackShare Page Detector R&D at LBNL (Denes) .pdf file (6.2MB) GaAs Detector (Durbin) .pdf file (450KB) Advanced...

424

MSTC - Microsystems Science, Technology, and Components - RF...  

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

band RF input and supplies N identical outputs (N4 or 8). SiGe, GaAs, GaN RFICs. Passive RF detectors - Pyroelectric microdetectors that produce a DC output proportional to...

425

Thursday Morning Sessions (June 27)  

Science Conference Proceedings (OSTI)

"Interfacial Barrier of LTG-Al0.3Ga0.7As Epitaxial Passivation in GaAs FETs:" N.X. NGUYEN, J.P. Ibbetson, U.K. Mishra, Electrical and Computer Engineering ...

426

JEM Table of Contents: June 1994 - TMS  

Science Conference Proceedings (OSTI)

569-576] G. Sreenivas, S.S. Ang, and W.D. Brown. Molecular Beam Deposition of Low-Resistance Polycrystalline GaAs [pp. 577-580] K. Mochizuki T. Nakamura, ...

427

Cogenerating Photovoltaic and Thermal Solar Collector  

E-Print Network (OSTI)

heat US Department of Energy: Parabolic Trough SpectroLab Concentrating Terrestrial PV Cell C1MJ CDO peak load and irradiance hours of the day #12;Design · Parabolic solar collector · GaAs PV cells

Eirinaki, Magdalini

428

band density of states whereas the higher energy side is deter-mined by the thermal distribution. With increasing tem-  

E-Print Network (OSTI)

. wavelength, pm ~ Fig. 4 Demonstration ofthe application ofan InAs, -.Sb, light emitting diode as a CO, sensor light emitting diodes on GaAs or Si substrates. The devices readily result in a new generation of infra

Chen, Sheng

429

First principle thousand atom quantum dot calculations  

E-Print Network (OSTI)

and A. Zunger, Appl. Phys. Lett. system bulk_CdSe (100)_CdSe (lll).CdSe (110)_CdSe (110)_GaAs Ap AE (meV) g (llO)-Si

Wang, Lin-Wang; Li, Jingbo

2004-01-01T23:59:59.000Z

430

Diamond Gyrotron Windows on the DIII-D Tokamak (A25103)  

E-Print Network (OSTI)

Proc. 30th Infrared Millimeter Wave Conf., Williamsburg, Virginia, 2005; General Atomics Report GA-A25103 (2005)30th International Conference on Infrared and Millimeter Waves Williamsburg Virginia, US, 2005999610845

Gorelov, I.A.

2005-08-10T23:59:59.000Z

431

II4, Compositionally-Graded Layers Composed of Tandem InGaAs ...  

Science Conference Proceedings (OSTI)

The specification of the 6° miscut is important because it provides step ..... of Metamorphic InGaP on GaAs and GaP for Wide-Bandgap Photovoltaic Junctions.

432

Substrate engineering for monolithic integration of III-V semiconductors with Si CMOS technology  

E-Print Network (OSTI)

Ge virtual substrates, fabricated using Si1-xGex-.Ge, compositionally graded buffers, enable the epitaxial growth of device-quality GaAs on Si substrates, but monolithic integration of III-V semiconductors with Si CMOS ...

Dohrman, Carl Lawrence

2008-01-01T23:59:59.000Z

433

Program Session VIII: Quantum Structures II - TMS  

Science Conference Proceedings (OSTI)

Self-Limiting OMCVD Growth of GaAs on V-Grooved Substrates with Application to InGaAs/GaAs Quantum Wires: Giorgio Biasol, Frank Reinhardt, Anders ...

434

Critical National Need Idea: High-performance Si-based ...  

Science Conference Proceedings (OSTI)

... These materials can be costly, in part, because of the high cost of single crystalline wafers such as SiC, GaAs, InP, Ge, CdZnTe, and GaSb, that are ...

2011-08-02T23:59:59.000Z

435

Search for Threshold Behavior in DIII-D Electron Heat Transport (A25092)  

E-Print Network (OSTI)

Proc. Of 32nd Euro. Conf. On Plasma Phys., Tarragona, Spain, 2005; General Atomics Report GA-A25092 (2005)32nd EPS Conference on Controlled Fusion and Plasma Physics Tarragona, ES, 2005999610780

Luce, T.C.

2005-07-07T23:59:59.000Z

436

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

437

preliminary technical program  

Science Conference Proceedings (OSTI)

Jun 20, 2000 ... 13. 2:40 PM, VII.A.-3. GaAs Single Electron Transistors and Logic Inverters Based on Schottky Wrap Gate Structures: S. Kasai1; H. Hasegawa1;.

438

Conceptual Design of the NGNP Reactor System (A27283)  

E-Print Network (OSTI)

Proc. Of 20th International Conf. On Nuclear Engineering, Anaheim, California, 2012; General Atomics Report GA-A27283 (2012)20th International Conference on Nuclear Engineering Anaheim California, US, 2012999619073

Richards, M.

2012-03-29T23:59:59.000Z

439

New GaInP/GaAs/GaInAs, Triple-Bandgap, Tandem Solar Cell for High-Efficiency Terrestrial Concentrator Systems  

DOE Green Energy (OSTI)

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

440

The solubility of hydrogen and deuterium in alloyed, unalloyed and impure plutonium metal  

DOE Green Energy (OSTI)

Pressure-Composition-Temperature (PCT) data are presented for the plutonium-hydrogen (Pu-H) and plutonium-deuterium (Pu-D) systems in the solubility region up to terminal solubility (precipitation of PuH{sub 2}). The heats of solution for PuH{sub s} and PuD{sub s} are determined from PCT data in the ranges 350-625 C for gallium alloyed Pu and 400-575 C for unalloyed Pu. The solubility of high purity plutonium alloyed with 2 at.% gallium is compared to high purity unalloyed plutonium. Significant differences are found in hydrogen solubility for unalloyed Pu versus gallium alloyed Pu. Differences in hydrogen solubility due to an apparent phase change are observable in the alloyed and unalloyed solubilities. The effect of iron impurities on Pu-Ga alloyed Pu is shown via hydrogen solubility data as preventing complete homogenization.

Richmond, Scott [Los Alamos National Laboratory; Bridgewater, Jon S [Los Alamos National Laboratory; Ward, John W [Los Alamos National Laboratory; Allen, Thomas A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

SOLDERING OF ALUMINUM BASE METALS  

DOE Patents (OSTI)

This patent deals with the soldering of aluminum to metals of different types, such as copper, brass, and iron. This is accomplished by heating the aluminum metal to be soldered to slightly above 30 deg C, rubbing a small amount of metallic gallium into the part of the surface to be soldered, whereby an aluminum--gallium alloy forms on the surface, and then heating the aluminum piece to the melting point of lead--tin soft solder, applying lead--tin soft solder to this alloyed surface, and combining the aluminum with the other metal to which it is to be soldered.

Erickson, G.F.

1958-02-25T23:59:59.000Z

442

Faraday rotation and sensitivity of (100) bismuth-substituted ferrite garnet films  

E-Print Network (OSTI)

We have investigated the Faraday rotation of in-plane magnetized bismuth-substituted ferrite garnet films grown by liquid phase epitaxy on (100) oriented gadolinium gallium garnet substrates. The Faraday spectra were measured for photon energies between 1.7- 2.6 eV. To interprete the spectra, we use a model based on two electric dipole transitions, one tetrahedral and one octahedral. Furthermore, the Faraday rotation sensitivity was measured at 2.3 eV, and found to be in good agreement with the theoretical predicitions. In particular, we find that the sensitivity increases linearly with the bismuth content and nonlinearly with the gallium content. 1 I.

L. E. Helseth; A. G. Solovyev; R. W. Hansen

2002-01-01T23:59:59.000Z

443

Synthesis and characterization of GaN thin films deposited on different substrates using a low-cost electrochemical deposition technique  

Science Conference Proceedings (OSTI)

Gallium nitride GaN thin films were deposited on three different substrates; Si (111), Si (100) and ITO coated glass using electrochemical deposition technique at 20 Degree-Sign C. A mixture of gallium nitrate, ammonium nitrate was used as electrolyte. The deposited films were investigated at room temperature by a series of material characterization techniques, namely; scanning electron microscopy (SEM), EDX and X-ray diffraction (XRD). SEM images and EDX results indicated that the growth of GaN films varies according to the substrates. XRD analyses showed the presence of hexagonal wurtzite and cubic zinc blende GaN phases with the crystallite size around 18-29 nm.

Al-Heuseen, K.; Hashim, M. R. [Al-Balqa Applied University, Ajloun University College (Jordan); School of Physics, Universiti Sains Malaysia, 11800-Penang (Malaysia)

2012-09-06T23:59:59.000Z

444

Optical method for automated real time control of elemental composition, distribution, and film thickness in CIGS solar cell production  

The solar industry has shown significant growth over the past decade. From 2002 to 2007 the market for Copper Indium Gallium Selenide (CIGS) grew at a 60% annual rate and it is estimated that the global CIGS market will grow to $7.6 billion by 2016. ...

445

Not Your Grandma's Quilt Researchers develop technique to keep cool high-power semiconductor  

E-Print Network (OSTI)

devices used in wireless applications, traffic lights and electric cars By Sean Nealon On MAY 8, 2012 in everything from traffic lights to electric cars. Gallium Nitride (GaN), a semiconductor material found by the Nano-Device Laboratory research group led byAlexander Balandin, professor of electrical engineering

446

Experience making mixed oxide fuel with plutonium from dismantled weapons  

Science Conference Proceedings (OSTI)

Mixed depleted UO{sub 2} and PuO{sub 2} (MOX) pellets prototypic of fuel proposed for use in commercial power reactors were made with plutonium recovered from dismantled weapons. We characterized plutonium dioxide powders that were produced at the Los Alamos and Lawrence Livermore National Laboratories (LANL and LLNL) using various methods to recover the plutonium from weapons parts and to convert It to oxide. The gallium content of the PUO{sub 2} prepared at LANL was the same as in the weapon alloy while the content of that prepared at LLNL was less. The MOX was prepared with a five weight percent plutonium content. We tested various MOX powders milling methods to improve homogeneity and found vibratory milling superior to ball milling. The sintering behavior of pellets made with the PuO{sub 2} from the two laboratories was similar. We evaluated the effects of gallium and of erbium and gadolinium, that are added to the MOX fuel as deplorable neutron absorbers, on the pellet fabrication process and an the sintered pellets. The gallium content of the sintered pellets was <10 ppm, suggesting that the gallium will not be an issue in the reactor, but that it will be an Issue in the operation of the fuel fabrication processing equipment unless it is removed from the PuO{sub 2} before it is blended with the UO{sub 2}.

Blair, H.T.; Ramsey, K.B.

1995-12-31T23:59:59.000Z

447

Aluminum battery alloys  

DOE Patents (OSTI)

Aluminum alloys suitable for use as anode structures in electrochemical cells are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

Thompson, D.S.; Scott, D.H.

1984-09-28T23:59:59.000Z

448

When you think of the film industry, what comes to mind? Entertainment. In this issue you will discover how films not only bring us the latest adventures but also are being sculptured at  

E-Print Network (OSTI)

rooftop market. Solyndra uses a copper-indium-gallium-diselenide (CIGS) absorber layer in its solar cell to create revolutionary optics, semiconductors, medical devices, and solar cells. Spring 2009 In This Issue information, visit: www.jbg3.net Alumni Spotlight Phil Kraus (B.S. '93) is the director of technology at solar

Demirel, Melik C.

449

Hydrogen, Fuel Cells, and Infrastructure Technologies FY 2002 Progress Report II.D Electrolytic Processes  

E-Print Network (OSTI)

" (in press: International Journal of Hydrogen Energy). 3. "Evaluation of RF-Sputtered Indium-Tin Oxide-Si:Ge), copper-indium-gallium-diselenide (CIGS), iron oxide (Fe2O3), etc.] that match energy requirements (Primary Contact) National Renewable Energy Laboratory 1617 Cole Blvd. Golden, CO 80401 (303) 275-4270, fax

450

Naval Postgraduate School Monterey, California 939435138  

E-Print Network (OSTI)

..............................................................................................................9 The Art of the Deal: How Can the Air Force Successfully Execute Renewable Energy Transactions of an Incident High-Energy Electromagnetic Beam ....21 Fusion Centers: Securing America's Homeland from Threats of an Incident High-Energy Electromagnetic Beam ... 23 Near-Field Imaging of Charge Transport in Gallium Nitride

451

Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution  

E-Print Network (OSTI)

Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution Aurélien David of photonic crystal PhC -assisted gallium nitride light-emitting diodes LEDs to the existence of unextracted a promising but challenging solution towards efficient solid-state lighting. Conventional GaN-based light-emitting

Recanati, Catherine

452

Energy Research and Development Division FINAL PROJECT REPORT  

E-Print Network (OSTI)

FOR GALLIUM NITRIDE LIGHT EMITTING DIODE DEVICES DECEMBER 2012 CEC5002013027 Prepared for: California Nitride Light Emitting Diode Devices is the final report for the grant, PIR10055, conducted by Applied the Energy Commission at 9163271551. #12;3 ABSTRACT For light emitting diodes (LEDs) to realiz

453

Aluminum battery alloys  

SciTech Connect

Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

Thompson, David S. (Richmond, VA); Scott, Darwin H. (Mechanicsville, VA)

1985-01-01T23:59:59.000Z

454

Catalysts for hydrocarbon conversion  

Science Conference Proceedings (OSTI)

Catalyst, particularly useful in catalytic reforming and for producing highly pure aromatic hydrocarbons, comprising an alumina carrier and containing, expressed in proportion of the weight of the alumina carrier: 005 to 1% of platinum 01 to 4% of gallium, indium or thallium 01 to 2% of tungsten, and 1 to 10% of halogen.

Le P. J.; Malmaison, R.; Marcilly, C.; Martino, G.; Miquel, J.

1980-08-12T23:59:59.000Z

455

FF1, n+GaAs Sheet Resistance Saturation and Implications to ...  

Science Conference Proceedings (OSTI)

These results can be explained via the interaction of three phenomena: a) an ... level, b) the tendency of gallium vacancies to form complexes with silicon donor ... B1, Phonon Engineering through Crystal Chemistry ... CC4, Response of Graphene-Based Field Effect Devices Exposed to Gamma and Neutron Irradiation.

456

In Situ Calibration of the SeaBird 9plus CTD Thermometer  

Science Conference Proceedings (OSTI)

A Sea-Bird Electronics (SBE 35) deep ocean reference thermometer is used with the SBE 9plus CTD system to calibrate the SBE 3 ocean thermometers of the CTD. The SBE 35 is standardized in water-triple-point and gallium-melting-point cells. The SBE ...

Hiroshi Uchida; Kentaro Ohyama; Satoshi Ozawa; Masao Fukasawa

2007-11-01T23:59:59.000Z

457

Monitoring interfacial dynamics by pulsed laser techniques. Final report  

DOE Green Energy (OSTI)

The research is aimed at understanding the structural, electronic, and reactive properties of semiconductors in solutions. Focus is on Si and GaAs surfaces because they are used in photovoltaic devices, etc. The pulsed laser techniques used included surface second harmonic generation in Si and laser induced photoluminescence in GaAs. SHG can measure space charge effects in the semiconductor under various conditions, ie, immersed in electrolyte, in presence of oxide overlayers, and under UHV conditions. The Si studies demonstrated the sensitivity of the phase of the SH response to space charge effects. With GaAs, time-correlated single photon counting methods were used in the picosecond time regime to examine the recombination luminescence following above band gap excitation (surface trapping velocities).

Richmond, G.

1995-12-31T23:59:59.000Z

458

Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)  

SciTech Connect

Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel [National Institute of Physics, University of the Philippines Diliman, Quezon City 1101 (Philippines); Que, Christopher T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila 1004 (Philippines); Yamamoto, Kohji; Tani, Masahiko [Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507 (Japan)

2012-12-15T23:59:59.000Z

459

Improved substrate structures for InP-based devices  

DOE Patents (OSTI)

A substrate structure for an InP-based semiconductor device having an InP-based film is disclosed. The substrate structure includes a substrate region having a light-weight bulk substrate and an upper GaAs layer. An interconnecting region is disposed between the substrate region and the InP-based device. The interconnecting region includes a compositionally graded intermediate layer substantially lattice matched at its one end to the GaAs layer and substantially lattice matched at its opposite end to the InP-based film. The interconnecting region further includes a dislocation mechanism disposed between the GaAs layer and the InP-based film in cooperation with the graded intermediate layer, the buffer mechanism blocking and inhibiting propagation of threading dislocations between the substrate region and the InP-based device. 1 fig.

Wanlass, M.; Sheldon, P.

1988-09-30T23:59:59.000Z

460

Substrate structures for InP-based devices  

DOE Patents (OSTI)

A substrate structure for an InP-based semiconductor device having an InP based film is disclosed. The substrate structure includes a substrate region having a lightweight bulk substrate and an upper GaAs layer. An interconnecting region is disposed between the substrate region and the InP-based device. The interconnecting region includes a compositionally graded intermediate layer substantially lattice-matched at one end to the GaAs layer and substantially lattice-matched at the opposite end to the InP-based film. The interconnecting region further includes a dislocation mechanism disposed between the GaAs layer and the InP-based film in cooperation with the graded intermediate layer, the buffer mechanism blocking and inhibiting propagation of threading dislocations between the substrate region, and the InP-based device.

Wanlass, Mark W. (Golden, CO); Sheldon, Peter (Lakewood, CO)

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Direct imaging of the structural domains in the iron pnictides AFe[subscript 2]As[subscript 2] (A=Ca, Sr, Ba)  

SciTech Connect

The parent compounds of recently discovered iron-arsenide superconductors, AFe{sub 2}As{sub 2} with alkaline earth A=Ca,Sr,Ba, undergo simultaneous structural and magnetic phase transitions at a temperature T{sub SM}. Using a combination of polarized light microscopy and spatially resolved high-energy synchrotron x-ray diffraction we show that the orthorhombic distortion leads to the formation of 45{sup o}-type structural domains in all parent compounds. Domains penetrate through the sample thickness in the c direction and are not affected by crystal imperfections such as growth terraces. The domains form regular stripe patterns in the plane with a characteristic dimension of 10--50 {mu}m. The direction of the stripes is fixed with respect to the tetragonal (100) and (010) directions but can change by 90{sup o} on thermal cycling through the transition. This domain pattern may have profound implications for intrinsic disorder and anisotropy of iron arsenides.

Tanatar, M.A.; Kreyssig, A.; Nandi, S.; Ni, N.; Bud'ko, S.L.; Canfield, P.C.; Goldman, A.I.; Prozorov, R.; (Ames)

2009-06-29T23:59:59.000Z

462

DPAL: A New Class of Lasers for CW Power Beaming at Ideal Photovoltaic Cell Wavelengths  

DOE Green Energy (OSTI)

The new class of diode pumped alkali vapor lasers (DPALs) offers high efficiency cw laser beams at wavelengths which efficiently couple to photovoltaic (PV) cells: silicon cells at 895 nm (cesium), and GaAs cells at 795 nm (rubidium) and at 770 nm (potassium). DPAL electrical efficiencies of 25-30% are projected, enabling PV cell efficiencies {approx}40% (Si) and {approx}60% (GaAs). Near-diffraction-limited DPAL device power scaling into the multi-kilowatt regime from a single aperture is projected.

Krupke, W F; Beach, R J; Payne, S A; Kanz, V K; Early, J T

2003-09-15T23:59:59.000Z

463

Suppression of nuclear spin diffusion at a GaAs/AlGaAs interface measured with a single quantum dot nano-probe  

E-Print Network (OSTI)

Nuclear spin polarization dynamics are measured in optically pumped individual GaAs/AlGaAs interface quantum dots by detecting the time-dependence of the Overhauser shift in photoluminescence (PL) spectra. Long nuclear polarization decay times of ~ 1 minute have been found indicating inefficient nuclear spin diffusion from the GaAs dot into the surrounding AlGaAs matrix in externally applied magnetic field. A spin diffusion coefficient two orders lower than that previously found in bulk GaAs is deduced.

A. E. Nikolaenko; E. A. Chekhovich; M. N. Makhonin; I. W. Drouzas; A. B. Vankov; J. Skiba-Szymanska; M. S. Skolnick; P. Senellart; A. Lemaitre; A. I. Tartakovskii

2009-01-15T23:59:59.000Z

464

Current-matched high-efficiency, multijunction monolithic solar cells  

DOE Patents (OSTI)

The efficiency of a two-junction (cascade) tandem photovoltaic device is improved by adjusting (decreasing) the top cell thickness to achieve current matching. An example of the invention was fabricated out of Ga.sub.0.52 In.sub.0.48 P and GaAs. Additional lattice-matched systems to which the invention pertains include Al.sub.x Ga.sub.1-x /GaAS (x= 0.3-0.4), GaAs/Ge and Ga.sub.y In.sub.l-y P/Ga.sub.y+0.5 In.sub.0.5-y As (0

Olson, Jerry M. (Lakewood, CO); Kurtz, Sarah R. (Golden, CO)

1993-01-01T23:59:59.000Z

465

Wednesday Afternoon Sessions (June 26) - TMS  

Science Conference Proceedings (OSTI)

... of 70 mW at room temperature for 260 um cavity length and a differential quantum .... "Polycrystalline MBE-Grown GaAs for Solar Cells:" D.J. FRIEDMAN, S.R. .... low noise applications including receivers, transmitters, and OEICs is clear.

466

Room-temperature electric-field controlled spin dynamics in ,,110... InAs quantum wells  

E-Print Network (OSTI)

Room-temperature electric-field controlled spin dynamics in ,,110... InAs quantum wells K. C. Halla pseudomagnetic fields exceeding 1 T when only 140 mV is applied across a single quantum well. Using this large­11 and the influence of the Rashba pseudomagnetic fields on the electron spin relaxation time in GaAs quantum wells

Flatte, Michael E.

467

Pulsed optically detected NMR of single GaAs/AlGaAs quantum wells  

E-Print Network (OSTI)

Pulsed optically detected NMR of single GaAs/AlGaAs quantum wells Marcus Eickhoff* and Dieter Suter, nanometer-sized quantum wells possible with excellent sensitivity and selectivity while avoiding.60.-k; 78.55.Cr; 78.67.De Keywords: ODNMR; Pulsed excitation; Quantum well; GaAs 1. Introduction Nuclear

Suter, Dieter

468

Influence of defect formation as a result of incorporation of a Mn {delta} layer on the photosensitiviy spectrum of InGaAs/GaAs quantum wells  

Science Conference Proceedings (OSTI)

The influence of defect formation upon the deposition of a Mn {delta} layer and a GaAs coating layer (with the use of laser evaporation) on the photosensitivity spectra of heterostructures with InGaAs/GaAs quantum wells located in the near-surface region has been studied.

Gorshkov, A. P., E-mail: gorskovap@phys.unn.ru; Karpovich, I. A.; Pavlova, E. D.; Kalenteva, I. L. [Lobachevsky State University of Nizhny Novgorod (Russian Federation)

2012-02-15T23:59:59.000Z

469

Mesoscopic Magnetic/Semiconductor Heterostructures  

Science Conference Proceedings (OSTI)

We report the experimental results of Fe and Fe3O4 nanostructures on GaAs(100) surfaces and hybrid Ferromagnetic/Semiconductor/Ferromagnetic (FM/SC/FM) spintronic devices. Element specific x-ray magnetic circular dichroism (XMCD) ... Keywords: Epitaxial ferromagnetic thin film, ferromagnetic/semiconductor hybrid structures, spintronics

Yong Bing Xu; E. Ahmad; Yong Xiong Lu; J. S. Claydon; Ya Zhai; G. van der Laan

2006-09-01T23:59:59.000Z

470

A 1-GSPS CMOS Flash A/D Converter for System-on-Chip Applications  

Science Conference Proceedings (OSTI)

Abstract: This paper presents an ultrafast CMOS flash A/D converter design and performance. Although the featured A/D converter is designed in CMOS, the performance is compatible to that of GaAs technology currently available. To achieve high-speed in ...

Jincheol Yoo; Kyusun Choi; Ali Tangel

2001-04-01T23:59:59.000Z

471

Theoretical calculations of the primary defects induced by pions and protons in SiC  

E-Print Network (OSTI)

In the present work, the bulk degradation of SiC in hadron (pion and proton) fields, in the energy range between 100 MeV and 10 GeV, is characterised theoretically by means of the concentration of primary defects per unit fluence. The results are compared to the similar ones corresponding to diamond, silicon and GaAs.

Sorina Lazanu; Ionel Lazanu; Emilio Borchi; Mara Bruzzi

2000-07-06T23:59:59.000Z

472

Optically-initiated silicon carbide high voltage switch  

DOE Patents (OSTI)

An improved photoconductive switch having a SIC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.

Caporaso, George J. (Livermore, CA); Sampayan, Stephen E. (Manteca, CA); Sullivan, James S. (Livermore, CA); Sanders, David M. (Livermore, CA)

2012-02-28T23:59:59.000Z

473

All-optical injection and control of spin and electrical currents in quantum wells Ali Najmaie, R. D. R. Bhat, and J. E. Sipe  

E-Print Network (OSTI)

All-optical injection and control of spin and electrical currents in quantum wells Ali Najmaie, R of the injected carriers. This degeneracy is lifted in a quantum well semiconductor structure due to confinement injection of electrical and spin currents in the plane of a GaAs quantum well and its control through

Sipe,J. E.

474

Characterization of MEMS sensor for RF transmitted power measurement  

Science Conference Proceedings (OSTI)

In this report we introduce the procedure for performing a thermo mechanical design and analysis of thermal GaAs-based MEMS devices. It will provide the procedure how thermal analysis should be made and model equations used to describe conduction, convection, ... Keywords: GaAs microsystems, MEMS, power sensor, thermal converter, thermo-mechanical simulations

Jiri Jakovenko; Miroslav Husak

2006-03-01T23:59:59.000Z

475

Regeneration Effect of Fluoride-rich Granular Activated Alumina on Desorption Regent NaOH Solution  

Science Conference Proceedings (OSTI)

As an effective adsorbent, granular activated alumina (GAA) has been widely used in defluoridation. In order to reduce cost and operate environment-friendly, the adsorbent should be regenerated. In this paper, column experiment was done to characterize ... Keywords: adsorption, regeneration, defluoridation, granular activated alumina

Baijie Niu; Wenming Ding; Dan Dang

2012-05-01T23:59:59.000Z

476

Automated Calculation of DIII-D Neutral Beam Availability (A23286)  

E-Print Network (OSTI)

In The Proc. Of The 18th IEEE/NPSS Symp. On Fusion Engineering, Albuquerque, New Mexico (Institute Of Electrical And Electronics Engineers, Inc., Piscataway, 1999) P. 511; And General Atomics Report GA-A23286 (1999)18th IEEE/NPSS Symposium on Fusion Engineering Albuquerque New Mexico, US, 1999985284369

Phillips, J.C.

1999-10-01T23:59:59.000Z

477

Design and Analyses of Transmission Lines for the 110 GHz ECH Upgrade to 6 MW for DIII-D (A23288)  

E-Print Network (OSTI)

In The Proc. Of The 18th IEEE/NPSS Symp. On Fusion Engineering, Albuquerque, New Mexico (Institute Of Electrical And Electronics Engineers, Inc., Piscataway, 1999) P. 499; And General Atomics Report GA-A23288 (1999)18th IEEE/NPSS Symposium on Fusion Engineering Albuquerque New Mexico, US, 1999997291689

Grunloh, H.J.

1999-10-01T23:59:59.000Z

478

Khesbn no. 79-80 - April 1975 - Journal  

E-Print Network (OSTI)

Tybiayaa^nx 80-79 py&na ,aû$anp ny¡o31 pK DnyiairïTa ,w p^dkpa.iya»x vi Bigpga'Da^n px ,anp lyay pa oiyoan yty^aaypvya nya ga^a "T pavT ax^x anp tra pnw ytiPT'» ya^aayaig pa

Admin, LAYCC

1975-01-01T23:59:59.000Z

479

Nanofaceting and alloy decomposition: From basic studies to advanced photonic devices  

Science Conference Proceedings (OSTI)

Most of the modern epitaxial structures for semiconductor lasers serving the needs of optical storage and fiber pumping are grown on misoriented GaAs(001) substrates. It has been found in metal-organic vapor-phase epitaxy that surface misorientation ... Keywords: Alloy decomposition, High resolution, Nanofaceting, Photonic bangap crystal laser, Polarized photoluminescence, Quantum well, Quantum wire, Transmission electron microscopy

V. A. Shchukin; N. N. Ledentsov; I. P. Soshnikov; N. V. Kryzhanovskaya; M. V. Maximov; N. D. Zakharov; P. Werner; D. Bimberg

2006-12-01T23:59:59.000Z

480

Lithography scaling issues associated with III-V MOSFETs  

Science Conference Proceedings (OSTI)

In this work we investigate fabrication issues associated with scaling down the gate length and source drain contact separation of a III-V MOSFET. We used high resolution electron-beam lithography and lift-off for gate and ohmic contact patterning to ... Keywords: E-beam, GaAs, Lift-off, MOSFET, PMMA, Resist thickness variation

O. Ignatova; S. Thoms; W. Jansen; D. S. Macintyre; I. Thayne

2010-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "gallium arsenide gaas" 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

Considerations of Selection of ECH System Transmission Line Waveguide Diameter for ITER (A25121)  

E-Print Network (OSTI)

Proc. 3rd Tech. Mtg On Electron Cyclotron Resonanxe Heating Physics And Technology For ITER, Como, Italy, 2005; General Atomics Report GA-A25121 (2005)3rd Technical Meeting on Electron Cyclotron Resonance Heating Physics and Technology for ITER Como, IT, 2005999610860

Olstad, R.A.

2005-07-07T23:59:59.000Z

482

Progress on Corrugated Waveguide Components Suitable for ITER ECH and Current Drive Transmission Lines (A27322)  

E-Print Network (OSTI)

Proc. Of 17th Electron Cyclotron Emission And Electron Cyclotron Resonance Heating, Deurne, The Netherlands, 2012; General Atomics Report GA-A27322 (2012)17th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating Deurne, NL, 2012999619079

Olstad, R.A.

2012-05-09T23:59:59.000Z

483

The Molecular Foundry User Proposal Form Proposal: MELOSH_05-04-2009_16-09-29  

E-Print Network (OSTI)

If other, then specify: Global Climate and Energy Project Affiliation Street Address: McCullough BuildingN and GaAs have been shown to exhibit very high quantum efficiencies with an appropriate surface coating.C.) If other, then specify: Affiliation Street Address: McCullough Building, Room 434, 476 Lomita Mall

Lee, Jason R.

484

Profiling the Built-in Electrical Potential in III-V Multijunction Solar Cells: Preprint  

DOE Green Energy (OSTI)

We report on a direct measurement of the electrical potential on cross-sections of GaInP2/GaAs multiple-junction solar cells by using an ultrahigh-vacuum scanning Kelvin probe microscope (UHV-SKPM). The UHV-SKPM allows us to measure the potential without air molecules being adsorbed on the cross-sectional surface. Moreover, it uses a GaAs laser with photon energy of 1.4 eV for the atomic force microscope (AFM) operation. This eliminated the light-absorption-induced bottom-junction flattening and top-junction enhancement, which happened in our previous potential measurement using a 1.85-eV laser for the AFM operation. Three potentials were measured at the top, tunneling, and bottom junctions. Values of the potentials are smaller than the potentials in the bulk. This indicates that the Fermi level on the UHV-cleaved (110) surface was pinned, presumably due to defects upon cleaving. We also observed higher potentials at atomic steps than on the terraces for both GaInP2 epitaxial layer and GaAs substrate. Combining scanning tunneling microscopy (STM) and SKPM measurements, we found that the potential height at steps of the GaAs substrate depends on the step direction, which is probably a direct result of unbalanced cations and anions at the steps.

Jiang, C.-S.; Friedman, D. J.; Moutinho, H. R.; Al-Jassim, M. M.

2006-05-01T23:59:59.000Z

485

Electron Subband Population and Mobility in Asymmetric Coupled Quantum Wells  

Science Conference Proceedings (OSTI)

The electron subband energy and population engineering by inserting a thin AlGaAs barrier inside a GaAs quantum well (QW) is considered. The specific voltage across the coupled QW's which arises due to the asymmetric deformation of electron wave function ... Keywords: electron-phonon scattering in a quantum well, photovoltaic effect

Juras Pozela; Karolis Pozela; Vida Juciene And Audrius Namajunas

1998-03-01T23:59:59.000Z

486

Energy Multiplier Module (EM^2) Using Innovation for Optimizing Small Reactor Capabilities (A27149)  

E-Print Network (OSTI)

Proc. Of IAEA Tech. Com. Mtg On Fuel And Fuel Cycle Options For Small And Medium Size Reactors, Vienna, Austria, 2011; General Atomics Report GA-A27149 (2011)IAEA Technical Committee Meeting on Fuel and Fuel Cycle Options for Small and Medium Size Reactors Vienna, AT, 2011999619070

Bertch, T.C.

2011-10-06T23:59:59.000Z

487

Selective Formation of Size-Controlled Silicon Nanocrystals by Photosynthesis in SiO Nanoparticle Thin Film  

Science Conference Proceedings (OSTI)

The SiOx thin film with a thickness of about 1 mum was formed on a GaAs substrate by bar-coating with the organic solution of the SiOx nanoparticles (~40 nm). The as-formed SiOx thin film consists of the SiOx ... Keywords: ${hbox{SiO}}_{x}$ , Nanocrystal, Raman, photosynthesis, self- limiting, silicon

Changyong Chen; S. Kimura; S. Nozaki; H. Ono; K. Uchida

2006-11-01T23:59:59.000Z

488

Optical and Quantum Electronics 27 (1995) 421-425 Precise nonselective chemically assisted  

E-Print Network (OSTI)

current density as low as 380Acm-2 with output power >11 mW are fabricated. Spatial uniformity is 5% overGaAs half-air-post VCSELs. Methods for analysing interference data for bulk GaAs and DBRs are also estab+ ion energy and the beam current density at sample are Acm -2, respectively

Lee, Yong-Hee

489

Bonding and gap states at GaAs-oxide interfaces  

Science Conference Proceedings (OSTI)

The nature of bonding and possible causes of Fermi level pinning at high mobility-high dielectric constant oxide GaAs:HfO"2 interfaces are discussed. It is argued that these are atoms with defective bonding, rather than states due to the bulk semiconductor ... Keywords: GaAs, bonding, interface

John Robertson; Liang Lin

2011-04-01T23:59:59.000Z

490

In situ atomic layer deposition and synchrotron-radiation photoemission study of Al2O3 on pristine n-GaAs(0 0 1)-4×6 surface  

Science Conference Proceedings (OSTI)

This work presents the in situ reflection high-energy electron diffraction (RHEED), scanning tunneling microscopy (STM) and synchrotron-radiation photoemission studies for the morphological and interfacial chemical characterization of in situ atomic ... Keywords: Atomic layer deposition, GaAs, Molecular beam epitaxy, Synchrotron-radiation photoemission

Y. H. Chang; M. L. Huang; P. Chang; J. Y. Shen; B. R. Chen; C. L. Hsu; T. W. Pi; M. Hong; J. Kwo

2011-07-01T23:59:59.000Z

491

Molecular beam epitaxy passivation studies of Ge and III-V semiconductors for advanced CMOS  

Science Conference Proceedings (OSTI)

Future CMOS technologies will require the use of substrate material with a very high mobility in order to fulfil the performance requirements. Therefore, combination of Ge p-MOS with n-MOS devices made out of high mobility III/V compounds, such as GaAs, ... Keywords: High mobility semiconductors, Molecular beam epitaxy (MBE), Passivation

C. Merckling; J. Penaud; D. Kohen; F. Bellenger; A. Alian; G. Brammertz; M. El-Kazzi; M. Houssa; J. Dekoster; M. Caymax; M. Meuris; M. M. Heyns

2009-07-01T23:59:59.000Z

492

Compound semiconductor MOSFETs  

Science Conference Proceedings (OSTI)

Enhancement mode, high electron mobility MOSFET devices have been fabricated using an oxide high-@k gate dielectric stack developed using molecular beam epitaxy. A template layer of Ga"2O"3, initially deposited on the surface of the III-V device unpins ... Keywords: Compound semiconductors, GaAs gate dielectric, III-V MOSFETs

R. Droopad; K. Rajagopalan; J. Abrokwah; P. Zurcher; M. Passlack

2007-09-01T23:59:59.000Z

493

The new -NMR facility at TRIUMF and applications in semiconductors  

E-Print Network (OSTI)

The new -NMR facility at TRIUMF and applications in semiconductors K.H. Chow a, Z. Salman b R facililty for conducting beta-detected nuclear magnetic resonance (-NMR) investigations of condensed matter facility are described, and some preliminary results on 8Li+ in GaAs are presented. Key words: -NMR

Baartman, Richard Abram

494

Friday Morning Sessions (June 28) - TMS  

Science Conference Proceedings (OSTI)

In spite of the fact that both bulk GaAs and GaN have rather large band gaps (1.5 and 3.2 eV respectively), we find a significant narrowing of the bandgap in the ...

495

Optically initiated silicon carbide high voltage switch  

DOE Patents (OSTI)

An improved photoconductive switch having a SiC or other wide band gap substrate material, such as GaAs and field-grading liners composed of preferably SiN formed on the substrate adjacent the electrode perimeters or adjacent the substrate perimeters for grading the electric fields.

Caporaso, George J. (Livermore, CA); Sampayan, Stephen E. (Manteca, CA); Sullivan, James S. (Livermore, CA); Sanders; David M. (Livermore, CA)

2011-02-22T23:59:59.000Z

496

Performance, Diagnostics, Controls and Plans for the Gyrotron System on the DIII-D Tokamak (A27312)  

E-Print Network (OSTI)

Proc. Of 17th Electron Cyclotron Emission And Electron Cyclotron Resonance Heating, Deurne, The Netherlands, 2012; General Atomics Report GA-A27312 (2012)17th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating Deurne, NL, 2012999619078

Lohr, J.

2012-05-09T23:59:59.000Z

497