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1

REPLY TO Al-TN OF: EM-421 SUBJECT:  

Office of Legacy Management (LM)

;;;;!r;; c"/ I%- , 2.1 + 2- ;;;;!r;; c"/ I%- , 2.1 + 2- llnited States Government Department of Energy memorandum Fw?fw --&a Gt3 .I\ DATE: Af'R 8 1991 REPLY TO Al-TN OF: EM-421 SUBJECT: Elimination of the Magnus Brass Manufacturing Company from FUSRAP TO: The File The Magnus Brass Manufacturing Company Sites are hereby eliminated from consideration in the Department of Energy's Formerly Utilized Sites Remedial Action Program (FUSRAP). The Department of Energy does not have the authority under the Atomic Energy Act to further investigate the sites, which are located at 533 Reading Road and 1029 West Seventh Street in Cincinnati, Ohio. The lack of authority is more fully explained in the attached Authority Review. The Department of Energy does not have any further information concerning the radiological status of the sites;

2

II United States Government DATE: REPLY TO Al-TN OF: SUBJECT...  

Office of Legacy Management (LM)

r.@& * EFG (07-W,' . II United States Government DATE: REPLY TO Al-TN OF: SUBJECT: TO: EM-421 (W. A. W illiams, 903-8149) Authorization for Remedial Action at the Former Baker...

3

REPLY TO AlTN OF: W-421 (W. A. W  

Office of Legacy Management (LM)

QOEF 13254 QOEF 13254 i.3891 EFG iO7W United- states Government bemoranduin DATE: f-!uG 3, 9 19g4 REPLY TO AlTN OF: W-421 (W. A. W illiams, 427-1719) SUBJECT: Elimination of the Sites from Program the Formerly Utilized Sites Remedial Action To' The File In 1990, with the assistance of Mr. reviewed a number of sites that had services to the Fernald facility as . _ Doug Tonkay and Us. Michelle Landis, I formerly provided goods and/or subcontractors. For 24 of .these B. . sites, recoaaaendations were made to ellrlnate them from further consideration under Fomerly Utilized Sites Remedial Action Program (FUSRAP). In each case, I made or reviewed the evaluation, and, in each case, a handwritten evaluation was prepared. This is to provide a more formal record of the decision on these sites and to ratify and confirm the

4

GA-AL-SC | Department of Energy  

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

GA-AL-SC GA-AL-SC GA-AL-SC October 1, 2012 ALA-1-N Wholesale Power Rate Schedule Area: PowerSouth Energy Cooperative System: Georgia-Alabama-South Carolina October 1, 2012 Duke-1-E Wholesale Power Rate Schedule Area: Duke On-System System: Georgia-Alabama-South Carolina October 1, 2012 Duke-2-E Wholesale Power Rate Schedule Area: Central System: Georgia-Alabama-South Carolina October 1, 2012 Duke-3-E Wholesale Power Rate Schedule Area: None System: Georgia-Alabama-South Carolina October 1, 2012 Duke-4-E Wholesale Power Rate Schedule Area: Duke Self-Schedulers System: Georgia-Alabama-South Carolina October 1, 2012 MISS-1-N Wholesale Power Rate Schedule Area: South Mississippi Electric Power Association System: Georgia-Alabama-South Carolina October 1, 2012 Pump-1-A Wholesale Power Rate Schedule

5

High Efficiency Large Area AlGaAs/GaAs Concentrator Solar Cells  

Science Journals Connector (OSTI)

A 1-kWp ( peak at 100 mw/cm2 incident power dencity ) concentrating photovoltaic array with 180 square Presnel plastic lenses and AlGaAs/GaAs concentrator solar cells has been constructed. The AlGaAs/GaAs concetr...

S. Yoshida; K. Mitsui; T. Oda; Y. Yukimoto…

1981-01-01T23:59:59.000Z

6

Self-aligned AlGaN/GaN transistors for sub-mm wave applications  

E-Print Network (OSTI)

This thesis describes work done towards realizing self-aligned AlGaN/GaN high electron mobility transistors (HEMTs). Self-aligned transistors are important for improving the frequency of AlGaN/GaN HEMTs by reducing source ...

Saadat, Omair I

2010-01-01T23:59:59.000Z

7

GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-Junction Solar Cells Under Concentration: Resistance Study  

SciTech Connect

The following four TJ designs, AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs are studied to determine minimum doping concentration to achieve a resistance of <10{sup -4} {omega}{center_dot}cm{sup 2} and a peak tunneling current suitable for MJ solar cells up to 1500-suns concentration (operating current of 21 A/cm{sup 2}). Experimentally calibrated numerical models are used to determine how the resistance changes as a function of doping concentration. The AlGaAs/GaAs TJ design is determined to require the least doping concentration to achieve the specified resistance and peak tunneling current, followed by the GaAs/GaAs, and AlGaAs/AlGaAs TJ designs. The AlGaAs/InGaP TJ design can only achieve resistances >5x10{sup -4} {omega}cm{sup 2}.

Wheeldon, Jeffrey F.; Valdivia, Christopher E.; Walker, Alex; Kolhatkar, Gitanja; Hall, Trevor J.; Hinzer, Karin [Centre for Research in Photonics, University of Ottawa, Ottawa, ON (Canada); Masson, Denis; Riel, Bruno; Fafard, Simon [Cyrium Technologies Inc., Ottawa, ON (Canada); Jaouad, Abdelatif; Turala, Artur; Ares, Richard; Aimez, Vincent [Centre de Recherche en Nanofabrication et en Nanocaracterisation CRN2, Universite de Sherbrooke, Sherbrooke, QC (Canada)

2010-10-14T23:59:59.000Z

8

Effect of buffer structures on AlGaN/GaN high electron mobility transistor reliability  

SciTech Connect

AlGaN/GaN high electron mobility transistors (HEMTs) with three different types of buffer layers, including a GaN/AlGaN composite layer, or 1 or 2 lm GaN thick layers, were fabricated and their reliability compared. The HEMTs with the thick GaN buffer layer showed the lowest critical voltage (Vcri) during off-state drain step-stress, but this was increased by around 50% and 100% for devices with the composite AlGaN/GaN buffer layers or thinner GaN buffers, respectively. The Voff - state for HEMTs with thin GaN and composite buffers were 100 V, however, this degraded to 50 60V for devices with thick GaN buffers due to the difference in peak electric field near the gate edge. A similar trend was observed in the isolation breakdown voltage measurements, with the highest Viso achieved based on thin GaN or composite buffer designs (600 700 V), while a much smaller Viso of 200V was measured on HEMTs with the thick GaN buffer layers. These results demonstrate the strong influence of buffer structure and defect density on AlGaN/GaN HEMT performance and reliability.

Liu, L. [University of Florida, Gainesville; Xi, Y. Y. [University of Florida, Gainesville; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL

2012-01-01T23:59:59.000Z

9

Radiation Hard AlGaN Detectors and Imager  

SciTech Connect

Radiation hardness of AlGaN photodiodes was tested using a 65 MeV proton beam with a total proton fluence of 3x10{sup 12} protons/cm{sup 2}. AlGaN Deep UV Photodiode have extremely high radiation hardness. These new devices have mission critical applications in high energy density physics (HEDP) and space explorations. These new devices satisfy radiation hardness requirements by NIF. NSTec is developing next generation AlGaN optoelectronics and imagers.

None

2012-05-01T23:59:59.000Z

10

Synthesis, morphology and optical properties of GaN and AlGaN semiconductor nanostructures  

SciTech Connect

Hexagonal Gallium Nitride (GaN) and Aluminum Gallium Nitride (AlGaN) nanoparticles were synthesized by sol-gel method using Ethylene Diamine Tetra Acetic acid (EDTA) complex route. Powder X-ray diffraction (PXRD) analysis confirms the hexagonal wurtzite structure of GaN and Al{sub 0.25}Ga{sub 0.75}N nanoparticles. Surface morphology and elemental analysis were carried out by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX). The room temperature Photoluminescence (PL) study shows the near band edge emission for GaN at 3.35 eV and at 3.59 eV for AlGaN nanoparticles. The Aluminum (Al) composition of 20% has been obtained from PL emission around 345 nm.

Kuppulingam, B., E-mail: drbaskar2009@gmail.com; Singh, Shubra, E-mail: drbaskar2009@gmail.com; Baskar, K., E-mail: drbaskar2009@gmail.com [Crystal Growth Centre, Anna University, Chennai-600025 (India)

2014-04-24T23:59:59.000Z

11

Multi-bands photoconductive response in AlGaN/GaN multiple quantum wells  

SciTech Connect

Based on the optical transitions among the quantum-confined electronic states in the conduction band, we have fabricated multi-bands AlGaN/GaN quantum well infrared photodetectors. Crack-free AlGaN/GaN multiple quantum wells (MQWs) with atomically sharp interfaces have been achieved by inserting an AlN interlayer, which releases most of the tensile strain in the MQWs grown on the GaN underlayer. With significant reduction of dark current by using thick AlGaN barriers, photoconductive responses are demonstrated due to intersubband transition in multiple regions with center wavelengths of 1.3, 2.3, and 4??m, which shows potential applications on near infrared detection.

Chen, G.; Rong, X.; Xu, F. J.; Tang, N. [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Wang, X. Q., E-mail: wangshi@pku.edu.cn; Shen, B., E-mail: bshen@pku.edu.cn [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Fu, K.; Zhang, B. S. [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Ruoshui Road 398, 215123 Suzhou (China); Hashimoto, H.; Yoshikawa, A. [Center for SMART Green Innovation Research, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Ge, W. K. [Department of Physics, Tsinghua University, Beijing 100871 (China)

2014-04-28T23:59:59.000Z

12

Simplified 2DEG carrier concentration model for composite barrier AlGaN/GaN HEMT  

SciTech Connect

The self consistent solution of Schrodinger and Poisson equations is used along with the total charge depletion model and applied with a novel approach of composite AlGaN barrier based HEMT heterostructure. The solution leaded to a completely new analytical model for Fermi energy level vs. 2DEG carrier concentration. This was eventually used to demonstrate a new analytical model for the temperature dependent 2DEG carrier concentration in AlGaN/GaN HEMT.

Das, Palash, E-mail: d.palash@gmail.com; Biswas, Dhrubes, E-mail: d.palash@gmail.com [Indian Institute of Technology Kharagpur, Kharagpur - 721302, West Bengal (India)

2014-04-24T23:59:59.000Z

13

Electron Transport in a Two-Dimensional Electron Gas at GaAs/AlGaAs Heterointerface  

E-Print Network (OSTI)

in condensed matters. Two-dimensional electron gas (2DEG) at the GaAs/AlGaAs hetero-interface o ersThesis Electron Transport in a Two-Dimensional Electron Gas at GaAs/AlGaAs Heterointerface under of the art samples, the mean free path of electrons exceeds 10;4 m at low temperature. The achievement

Katsumoto, Shingo

14

Study and development of tunable, single mode AlGaAs/GaAs lasers  

SciTech Connect

Liquid phase epitaxy has been employed in this study to fabricate two-section wavelength tunable lasers. GaAs/AlGaAs and In GaAsP/InP material system have been used for fabricating the lasers. Both direct (butt) coupling and evanescent coupling approaches have been studied. The complications associated with the regrowth process have been responsible for poor laser performance. Some DBR gratings for three-section lasers have been made using the electron beam lithography at UCSD. A simple set up has been tested to measure the wavelength shift of GaAs/AlGaAs lasers. Also, a simple structure which avoids the regrowth process has been proposed for the two-section laser. 9 refs., 14 figs.

Yu, P.K.L.; Liu, J.C. (California Univ., San Diego, La Jolla, CA (USA). Dept. of Electrical and Computer Engineering)

1990-09-01T23:59:59.000Z

15

Radio-frequency reflectometry on an undoped AlGaAs/GaAs single electron transistor  

SciTech Connect

Radio frequency reflectometry is demonstrated in a sub-micron undoped AlGaAs/GaAs device. Undoped single electron transistors (SETs) are attractive candidates to study single electron phenomena, due to their charge stability and robust electronic properties after thermal cycling. However, these devices require a large top-gate, which is unsuitable for the fast and sensitive radio frequency reflectometry technique. Here, we demonstrate that rf reflectometry is possible in an undoped SET.

MacLeod, S. J.; See, A. M.; Keane, Z. K.; Scriven, P.; Micolich, A. P.; Hamilton, A. R., E-mail: Alex.Hamilton@unsw.edu.au [School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Aagesen, M.; Lindelof, P. E. [Nanoscience Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark)] [Nanoscience Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen (Denmark)

2014-01-06T23:59:59.000Z

16

Reaktive Molekularstrahlepitaxie und Charakterisierung von GaN/(Al,Ga)N-Heterostrukturen auf SiC(0001).  

E-Print Network (OSTI)

??Thema dieser Arbeit ist die Synthese von hexagonalen GaN/(Al,Ga)N-Heterostrukturen mittels reaktiver Molekularstrahlepitaxie (MBE) auf SiC(0001)-Substraten. Der Einfluß der Wachstumsbedingungen auf die strukturellen, morphologischen, optischen und… (more)

Thamm, Andreas

2001-01-01T23:59:59.000Z

17

Electron tunneling spectroscopy study of electrically active traps in AlGaN/GaN high electron mobility transistors  

SciTech Connect

We investigate the energy levels of electron traps in AlGaN/GaN high electron mobility transistors by the use of electron tunneling spectroscopy. Detailed analysis of a typical spectrum, obtained in a wide gate bias range and with both bias polarities, suggests the existence of electron traps both in the bulk of AlGaN and at the AlGaN/GaN interface. The energy levels of the electron traps have been determined to lie within a 0.5?eV band below the conduction band minimum of AlGaN, and there is strong evidence suggesting that these traps contribute to Frenkel-Poole conduction through the AlGaN barrier.

Yang, Jie, E-mail: jie.yang@yale.edu; Cui, Sharon; Ma, T. P. [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520 (United States)] [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520 (United States); Hung, Ting-Hsiang; Nath, Digbijoy; Krishnamoorthy, Sriram; Rajan, Siddharth [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

2013-11-25T23:59:59.000Z

18

GaAs/AlGaAs quantum wells with indirect-gap AlGaAs barriers for solar cell applications  

SciTech Connect

We have fabricated GaAs/AlGaAs quantum well (QW) solar cells in which 3?nm-thick QWs and indirect-gap Al{sub 0.78}Ga{sub 0.22}As barriers are embedded, and we studied extraction processes of photogenerated carriers in this QW system. The photocurrent under 700?nm light illumination at voltages close to the open-circuit voltage shows only a small reduction, indicating that the carrier recombination inside QWs is largely suppressed. We attribute this result to an efficient extraction of electrons from the QWs through the X-valley of AlGaAs. The insertion of QWs is shown to be effective in extending the absorption wavelengths and in enhancing the photocurrent. The use of indirect-gap materials as barriers is found to enhance carrier extraction processes, and result in an improved performance of QW solar cells.

Noda, T., E-mail: NODA.Takeshi@nims.go.jp; Otto, L. M.; Elborg, M.; Jo, M.; Mano, T.; Kawazu, T.; Han, L. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Sakaki, H. [National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Toyota Technological Institute, Nagoya 468-8511 (Japan)

2014-03-24T23:59:59.000Z

19

Direct observation of Ga-rich microdomains in crack-free AlGaN grown on patterned GaNsapphire substrates  

E-Print Network (OSTI)

.e., a homogeneous aluminum content, is found near the sample surface. However, the strong rise of quantum efficiency for AlGaN because the Al alloys also nucleate on the mask materials. Recently, growth on patterned structured into a periodic grid of trenches and terraces along 1100 . Prior to the final AlGaN ( Al 0

Nabben, Reinhard

20

Chemical beam epitaxy growth of AlGaAs/GaAs tunnel junctions using trimethyl aluminium for multijunction solar cells  

SciTech Connect

AlGaAs/GaAs tunnel junctions for use in high concentration multijunction solar cells were designed and grown by chemical beam epitaxy (CBE) using trimethyl aluminium (TMA) as the p-dopant source for the AlGaAs active layer. Controlled hole concentration up to 4?10{sup 20} cm{sup ?3} was achieved through variation in growth parameters. Fabricated tunnel junctions have a peak tunneling current up to 6140 A/cm{sup 2}. These are suitable for high concentration use and outperform GaAs/GaAs tunnel junctions.

Paquette, B.; DeVita, M.; Turala, A.; Kolhatkar, G.; Boucherif, A.; Jaouad, A.; Aimez, V.; Arès, R. [Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, Québec (Canada)] [Institut Interdisciplinaire d'Innovation Technologique (3IT), Université de Sherbrooke, Sherbrooke, Québec (Canada); Wilkins, M.; Wheeldon, J. F.; Walker, A. W.; Hinzer, K. [Centre for Research in Photonics, University of Ottawa, Ottawa, ON (Canada)] [Centre for Research in Photonics, University of Ottawa, Ottawa, ON (Canada); Fafard, S. [Cyrium Technologies Inc., Ottawa, ON (Canada)] [Cyrium Technologies Inc., Ottawa, ON (Canada)

2013-09-27T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

GaAs single quantum dot embedded into AlGaAs nanowire  

SciTech Connect

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

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

2013-12-04T23:59:59.000Z

22

Electronic properties of the AlGaN/GaN heterostructure and two-dimensional electron gas observed by electroreflectance  

Science Journals Connector (OSTI)

A contacted electroreflectance technique was used to investigate AlGaN/GaN heterostructures and their intrinsic electric field-induced properties. By studying variations in the electroreflectance with applied field spectral features associated with the AlGaN barrier the two-dimensional electron gas at the interface and bulk GaN were identified. Barrier-layer composition and electric field were determined from the AlGaN Franz–Keldysh oscillations. For a high mobilityheterostructure grown on SiC measured AlGaN polarizationelectric field and two-dimensional electron gas density approached values predicted by a standard bandstructure model. The two-dimensional electron gas produced a broad field-tunable first derivative electroreflectance feature. With a dielectric function calculation we describe the line shape and relative amplitude of the two-dimensional electron gas electroreflectance feature for a wide range of electron density and applied field values.

S. R. Kurtz; A. A. Allerman; D. D. Koleske; A. G. Baca; R. D. Briggs

2004-01-01T23:59:59.000Z

23

Optimisation of doping cladding layers in AlGaInP/GaInP laser heterostructures  

SciTech Connect

The influence of cladding doping level on the characteristics of laser diodes, which are based on an AlGaInP/GaInP/GaAs system and emit at wavelengths of 670-680 nm, is studied. It is shown experimentally that, as the ratio of the cladding doping levels P/N increases, the inversion current density J{sub 0} and the differential gain {beta} also increase. A monotonic increase in the characteristic temperature T{sub 0} accompanies this process. The internal quantum yield {eta}{sub 0} of stimulated recombination has a maximum at P/N=2.1. Laser diodes with a mesastripe width of 100 {mu}m are manufactured. The cw radiation power emitted by them is as high as 1000 mW at an efficiency of 1.55 W A{sup -1}. (active media. lasers)

Chel'nyi, A A; Aluev, A V; Maslov, S V [M.F. Stel'makh Polyus Research and Development Institute, Moscow (Russian Federation)

2004-01-31T23:59:59.000Z

24

Nonlinear optical waveguides based on near-infrared intersubband transitions in GaN/AlN  

E-Print Network (OSTI)

. Hasama, "Subpicosecond saturation of intersubband absorption in (CdS/ZnSe)/BeTe quantum well waveguides. Cho, "Intersubband absorption at ~ 1.55 m in well- and modulation-doped GaN/AlGaN multiple quantum

25

Persistent photoconductivity in AlGaN/GaN heterojunction channels caused by the ionization of deep levels in the AlGaN barrier layer  

SciTech Connect

Time-dependent responses of drain current (I{sub d}) in an AlGaN/GaN HEMT under UV (3.3 eV) and red (2.0 eV) light illumination have been studied at 300 K and 250 K. UV illumination enhances I{sub d} by about 10 %, indicating that the density of two-dimensional electrons is raised by about 10{sup 12} cm{sup ?2}. When UV light is turned off at 300 K, a part of increased I{sub d} decays quickly but the other part of increment is persistent, showing a slow decay. At 250 K, the majority of increment remains persistent. It is found that such a persistent increase of I{sub d} at 250 K can be partially erased by the illumination of red light. These photo-responses are explained by a simple band-bending model in which deep levels in the AlGaN barrier get positively charged by the UV light, resulting in a parabolic band bending in the AlGaN layer, while some potion of those deep levels are neutralized by the red light.

Murayama, H.; Akiyama, Y.; Niwa, R.; Sakashita, H.; Sakaki, H. [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511 (Japan); Kachi, T. [Toyota Central R and D Labs., Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192 (Japan); Sugimoto, M. [Toyota Motor Corporation, 543 Kirigahora, Nishihirose-cho, Toyota, Aichi 470-0309 (Japan)

2013-12-04T23:59:59.000Z

26

Nitrogen-concentration control in GaNAs/AlGaAs quantum wells using nitrogen ?-doping technique  

SciTech Connect

GaNAs/Al{sub 0.35}Ga{sub 0.65}As multiple quantum wells (MQWs) with nitrogen ?-doping were fabricated on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. High controllability of nitrogen-concentrations in the MQWs was achieved by tuning nitrogen ?-doping time. The maximum nitrogen concentration in the MQWs was 2.8%. The MQWs exhibit intense, narrow photoluminescence emission.

Mano, Takaaki; Jo, Masafumi; Kuroda, Takashi; Noda, Takeshi; Sugimoto, Yoshimasa; Sakuma, Yoshiki [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Elborg, Martin; Sakoda, Kazuaki [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan and Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

2014-05-15T23:59:59.000Z

27

Composition pulling effect and strain relief mechanism in AlGaN/AlN distributed Bragg reflectors  

SciTech Connect

We report on the composition pulling effect and strain relief mechanism in AlGaN/AlN distributed Bragg reflectors (DBRs) grown on GaN template/{alpha}-Al{sub 2}O{sub 3}(0001) by metal organic chemical vapor deposition. The reciprocal space mapping contours reveal that these DBRs are coherently grown. Cross-section transmission electron microscopy image of the AlGaN/AlN DBRs and the energy-dispersive x-ray analysis indicate that an AlGaN layer with gradient Al composition is located between the Al{sub 0.4}Ga{sub 0.6}N and AlN layers along the [0001] direction. It is attributed to the fact that Ga atoms in AlGaN are pulled and segregated to the upper layer by the strain. The density of strain energy is estimated to reduce more than one order by forming this quasi-three-sublayer structure comparing to the designed bi-sublayer structure.

Liu, B.; Zhang, R.; Ji, X. L.; Fu, D. Y.; Xie, Z. L.; Chen, D. J.; Chen, P.; Jiang, R. L.; Zheng, Y. D. [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China); Zheng, J. G. [California Institute for Telecommunications and Information Technology, University of California, Irvine, California 92697-2800 (United States)

2011-06-27T23:59:59.000Z

28

Large linear magnetoresistance in a GaAs/AlGaAs heterostructure  

SciTech Connect

We report non-saturating linear magnetoresistance (MR) in a two-dimensional electron system (2DES) at a GaAs/AlGaAs heterointerface in the strongly insulating regime. We achieve this by driving the gate voltage below the pinch-off point of the device and operating it in the non-equilibrium regime with high source-drain bias. Remarkably, the magnitude of MR is as large as 500% per Tesla with respect to resistance at zero magnetic field, thus dwarfing most non-magnetic materials which exhibit this linearity. Its primary advantage over most other materials is that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K to 10 K), thus making it an attractive candidate for cryogenic sensor applications.

Aamir, Mohammed Ali, E-mail: aamir@physics.iisc.ernet.in; Goswami, Srijit, E-mail: aamir@physics.iisc.ernet.in; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Baenninger, Matthias; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Tripathi, Vikram [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)

2013-12-04T23:59:59.000Z

29

Enhanced optical property in quaternary GaInAsSb/AlGaAsSb quantum wells  

SciTech Connect

High quality GaInAsSb/AlGaAsSb quantum wells (QWs) have been grown by molecular beam epitaxy using proper interface treatments. By controlling the group-V elements at interfaces, we obtained excellent optical quality QWs, which were free from undesired localized trap states, which may otherwise severely affect the exciton recombination. Strong and highly efficient exciton emissions up to room temperature with a wavelength of 2.2 ?m were observed. A comprehensive investigation on the QW quality was carried out using temperature dependent and power dependent photoluminescence (PL) measurements. The PL emission intensity remains nearly constant at low temperatures and is free from the PL quenching from the defect induced localized states. The temperature dependent emission energy had a bulk-like behavior, indicating high quality well/barrier interfaces. Because of the uniformity of the QWs and smooth interfaces, the low temperature limit of inhomogeneous line width broadening is as small as 5?meV.

Lin, Chien-Hung, E-mail: chlin.ee97g@g2.nctu.edu.tw; Lee, Chien-Ping [Department of Electronics Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)

2014-10-21T23:59:59.000Z

30

GaN/ZnO and AlGaN/ZnO heterostructure LEDs: growth, fabrication, optical and electrical characterization  

E-Print Network (OSTI)

radiation hardness than Si, GaAs, CdS and GaN, therefore it should be suitable for space applications. Last novel optoelectronic devices circumventing the problem of p-type doping of ZnO. In such Al devices become reality: the problem of p-type doping of ZnO. So far, there is no way to reliably produce

Wetzel, Christian M.

31

AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium titanate  

E-Print Network (OSTI)

AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium-effect transistors have been formed by incorporating barium strontium titanate (BST) deposited by rf magnetron in increased leakage. Due to its large dielectric constant, barium strontium ti- tanate [Ba1-xSrxTiO3, (BST

York, Robert A.

32

High-Performance Integrated Dual-Gate AlGaN/GaN Enhancement-Mode Transistor  

E-Print Network (OSTI)

In this letter, we present a new AlGaN/GaN enhancement-mode (E-mode) transistor based on a dual-gate structure. The dual gate allows the transistor to combine an E-mode behavior with low on-resistance and very high breakdown ...

Lu, Bin

33

High Breakdown ( > \\hbox {1500 V} ) AlGaN/GaN HEMTs by Substrate-Transfer Technology  

E-Print Network (OSTI)

In this letter, we present a new technology to increase the breakdown voltage of AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on Si substrates. This new technology is based on the removal of the original Si ...

Lu, Bin

34

An AlGaAsGaAs quantum cascade laser operating with a thermoelectric cooler for spectroscopy of NH3  

E-Print Network (OSTI)

out using a compact thermo-electrically cooled laser package. The QCL described here is designedAn AlGaAs­GaAs quantum cascade laser operating with a thermoelectric cooler for spectroscopy of NH3. Langford b a Department of Electronics and Electrical Engineering, Rankine Building, University of Glasgow

35

Ga[sub 13], Al[sub 13], GaAl[sub 12], and chromium-pillared montmorillonites: Acidity and reactivity for cumene conversion  

SciTech Connect

A comparison has been made of the acidic characters of a series of metal polyoxocation pillar interlayered clay minerals (M-PILCs) by studying the infrared spectra of adsorbed pyridine. These comparisons were made for Ga[sub 13]-, Al[sub 13]- and GaAl[sub 12]-PILCs, and for Na[sup +]-exchanged montmorillonite (Na-STx-1). The Ga[sub 13]-PILC, was found to exhibit the strongest Lewis acid sites, followed by the AL[sub 13]-, and GaAl[sub 12]-PILCs and then by the Ns-STx-1. The relative number of Lewis acid sites, however, was found to be much greater for the GaAl[sub 12]-PILC, particularly after calcination at higher temperatures, indicating that the Ga[sub 13] Lewis acid sites did not have as high a thermal stability. The Broensted acidic characters for the pillared clays depend on the pillar, and follow the general decreasing order of abundance of GaAl[sub 12]-, Al[sub 13], and Ga[sub 13]-PILC when expressed as absorbance per unit mass. When the acidities per unit surface area were estimated, however, the Ga[sub 13]-PILCs were found to have the greatest number. This indicated that while the pillars contribute to the PILC acidities primarily through increasing the exposed phyllosilicate sheet surface areas, there is also a significant effect arising from the acidic characters of the pillars themselves. The dehydrogenation activities of Ga[sub 13]-, GaAl[sub 12]-, Al[sub 13]-, and Na-STx-1, in addition to a chromium polyoxocation-PILC, were compared by observing the products formed upon reaction with the model compound cumene. The Ga[sub 13]- and chromium-PILCs and the Na-Stx-1 exhibited almost exclusively dehydrogenation activities, whereas the Al[sub 13]- and GaAl[sub 12]-PILCs exhibited both cracking and dehydrogenation behaviors. These results prove that the pillars themselves can very strongly effect the catalytic activities of the PILCs. 3 refs., 6 figs., 2 tabs.

Bradley, S.M.; Kydd, R.A. (Univ. of Calgary, Alberta (Canada))

1993-05-01T23:59:59.000Z

36

Temperature dependence of optical transitions in AlGaAs  

Science Journals Connector (OSTI)

AlGaAs structures with different aluminum concentration (x=0.0 0.17 0.30 and 0.40) were characterized by photoluminescence and photoreflectance techniques. The temperature dependence of optical transitions in the temperature ranging from 2 to 300 K were investigated. Y. P. Varshni [Physica (Utrecht) 34 194 (1967)] L. Viña et al. [Phys. Rev. B 30 1979 (1984)] and R. Pässler [Phys. Status Solidi B 200 155 (1997)] models were used to fit the experimental points. The Pässler model gave the best adjustment to the experimental points. The tree models showed that the empirical parameters obtained through the adjustment of the experimental data in the three different models are aluminum composition dependent in the ternary alloy.

S. A. Lourenço; I. F. L. Dias; J. L. Duarte; E. Laureto; E. A. Meneses; J. R. Leite; I. Mazzaro

2001-01-01T23:59:59.000Z

37

Effect of AlGaN/GaN strained layer superlattice period on InGaN MQW laser diodes[Multiple Quantum Wells  

SciTech Connect

AlGaN/GaN strained layer superlattices have been employed in the cladding layers of InGaN multi-quantum well laser diodes grown by metalorganic chemical vapor deposition (MOCVD). Superlattices have been investigated for strain relief of the cladding layer, as well as an enhanced hole concentration, which is more than ten times the value obtained for bulk AlGaN films. Laser diodes with strained layer superlattices as cladding layers were shown to have superior structural and electrical properties compared to laser diodes with bulk AlGaN cladding layers. As the period of the strained layer superlattices is decreased, the threshold voltage, as well as the threshold current density, is decreased. The resistance to vertical conduction through p-type superlattices with increasing superlattice period is not offset by the increase in hole concentration for increasing superlattice spacing, resulting in higher voltages.

Hansen, M.; Abare, A.C.; Kozodoy, P.; Katona, T.M.; Craven, M.D.; Speck, J.S.; Mishra, U.K.; Coldren, L.A.; DenBaars, S.P.

2000-07-01T23:59:59.000Z

38

Magnetic-field effects on quasi-two-dimensional excitons in coupled GaAs?(Ga,Al)As quantum wells  

Science Journals Connector (OSTI)

We have used the variational procedure in the effective-mass and nondegenerate parabolic band approximations in order to investigate the effects of a magnetic field on the exciton effective mass and dispersion in semiconductor heterostructures. Calculations are performed for bulk GaAs, and two-dimensional and quasi-two-dimensional excitons in coupled GaAs?(Ga,Al)As quantum wells for applied magnetic fields perpendicular to the layers. A simple hydrogenlike envelope wave function provides the expected behavior for the exciton dispersion in a wide range of the center-of-mass momenta, and an analytical expression for the exciton effective mass is obtained. Present results lead to a magnetic-field dependent exciton effective mass and dispersion in quite good agreement with available experimental measurements in coupled GaAs?(Ga,Al)As quantum wells.

E. Reyes-Gómez, L. E. Oliveira, and M. de Dios-Leyva

2005-01-14T23:59:59.000Z

39

MOCVD Growth of AlGaInN for UV Emitters  

SciTech Connect

Issues related to the growth of nitride-based UV emitters are investigated in this work. More than 100 times of improved in the optical efficiency of the GaN active region can be attained with a combination of raising the growth pressure and introducing a small amount of indium. The unique issue in the UV emitter concerning the use of AlGaN for confinement and the associated tensile cracking is also investigated. They showed that the quaternary AlGaInN is potentially capable of providing confinement to GaN and GaN:In active regions while maintaining lattice matching to GaN, unlike the AlGaN ternary system.

Crawford, Mary; Han, Jung

1999-07-07T23:59:59.000Z

40

Short-period superlattices of AlN/Al0.08Ga0.92N grown on AlN substrates S. A. Nikishin,a)  

E-Print Network (OSTI)

American Institute of Physics. [DOI: 10.1063/1.1815056] Layers of AlGaN with high content of AlN suffer (LEDs) and solar blind pho- todetectors. Short period superlattices (SPSLs) of AlN/Al0.08Ga0.92N maxima. The analysis of the central peak of the RSM shows a high degree of lateral co- herence of 44 m

Holtz, Mark

Note: This page contains sample records for the topic "tn al ga" 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

60 GHz Harmonic Optoelectronic Up-Conversion Using an InAlAs/InGaAs Metamorphic High-Electron-Mobility Transistor on a GaAs Substrate  

E-Print Network (OSTI)

60 GHz Harmonic Optoelectronic Up-Conversion Using an InAlAs/InGaAs Metamorphic High optoelectronic up-conversion using an InAlAs/InGaAs metamorphic high-electron-mobility transistor (HEMT) on a Ga 1 GHz signals into a 60 GHz band. After investigating the dependences of optoelectronic mixing

Choi, Woo-Young

42

Inductively Coupled Plasma Reactive Ion Etching of AlGaAsSb and InGaAsSb for Quaternary Antimonide MIM Thermophotovoltaics  

SciTech Connect

In this letter we report on the inductively coupled plasma reactive ion etching (ICP-RIE) of InGaAsSb and AlGaAsSb for the fabrication of quaternary monolithic interconnected module (MIM) thermophotovoltaic (TPV) devices. A rapid dry etch process is described that produces smooth surfaces using BCl[sub]3 for AlGaAsSb and InGaAsSb capped with GaSb. Uncapped InGaAsSb was etched by adding an H[sub]2 plasma preclean to reduce surface oxides. InGaAsSb etch rate was studied as a function of accelerating voltage, RF power, temperature and pressure. The etch conditions found for InGaAsSb were used for AlGaAsSb etching to determine the effectiveness for isolation of the MIM cells.

Palmisiano, M. N.; Peake, G. M.; Shul, R. J.; Ashby, C. I.; Cederberg, J. G.; Hafich, M. J.; Biefeld, R. M.

2002-10-01T23:59:59.000Z

43

Identification of the Parasitic Chemical Reactions during AlGaN OMVPE  

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

Identification of the Parasitic Chemical Reactions during AlGaN OMVPE Identification of the Parasitic Chemical Reactions during AlGaN OMVPE by J. R. Creighton, M. E. Coltrin, and W. G. Breiland Motivation-GaN and AlGaN alloys are ex- tremely important materials with widespread applications for optoelectronics (e.g. solid state lighting) and high power electronics. Or- ganometallic vapor phase epitaxy (OMVPE) is the primary deposition methodology, but it suf- fers from several growth chemistry anomalies. Growth rate and alloy composition are often a sensitive function of temperature and other reac- tor variables. These factors make the AlGaN OMVPE process difficult to control and in- crease the cost of the material. Conventional wisdom has been that the non-ideal OMVPE behavior is due to parasitic "pre-reactions" be-

44

Interband transitions in molecular?beam?epitaxial Al x Ga1?x As/GaAs  

Science Journals Connector (OSTI)

Interband transition energies for Al x Ga1?x As layers grown by molecular?beam epitaxy(MBE) techniques have been determined using the electrolyte electroreflectance (EER) technique. The observed data fit quadratic relations for E 0 E 0+?0 E 1 and E 1+?1 to describe variations of energy with composition. Although the x values were not accurately known the internal consistency of the data is excellent. Given a single bowing parameter we show that accurate values of x can be determined. The EER technique can provide x values with an accuracy better than 0.02 and information on changes in x as small as 0.002. It is thus ideally suited for studying MBE materials.

J. L. Aubel; U. K. Reddy; S. Sundaram; W. T. Beard; James Comas

1985-01-01T23:59:59.000Z

45

Reliability of AlGaN/GaN high electron mobility transistors on low dislocation density bulk GaN substrate: Implications of surface step edges  

SciTech Connect

To enable gaining insight into degradation mechanisms of AlGaN/GaN high electron mobility transistors, devices grown on a low-dislocation-density bulk-GaN substrate were studied. Gate leakage current and electroluminescence (EL) monitoring revealed a progressive appearance of EL spots during off-state stress which signify the generation of gate current leakage paths. Atomic force microscopy evidenced the formation of semiconductor surface pits at the failure location, which corresponds to the interaction region of the gate contact edge and the edges of surface steps.

Killat, N., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk; Montes Bajo, M.; Kuball, M., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk [Center for Device Thermography and Reliability (CDTR), H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Paskova, T. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States) [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Materials Science and Engineering Department, North Carolina State University, Raleigh, North Carolina 27695 (United States); Evans, K. R. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States)] [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Leach, J. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States) [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Li, X.; Özgür, Ü.; Morkoç, H. [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Chabak, K. D.; Crespo, A.; Gillespie, J. K.; Fitch, R.; Kossler, M.; Walker, D. E.; Trejo, M.; Via, G. D.; Blevins, J. D. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)] [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)

2013-11-04T23:59:59.000Z

46

Energy relaxation of hot electrons in lattice-matched AlInN/AlN/GaN heterostructures  

SciTech Connect

Using the dielectric continuum model, hot-electron power dissipation and energy relaxation times are calculated for a typical lattice-matched AlInN/AlN/GaN heterostructure, including effects of hot phonons and screening from the mobile electrons. The calculated power dissipation and energy relaxation times are very close to the experimental data.

Zhang, J.-Z.; Dyson, A. [Department of Physics, University of Hull, Hull, HU6 7RX (United Kingdom); Ridley, B. K. [School of Computing Science and Electronic Engineering, University of Essex, Colchester, CO4 3SQ (United Kingdom)

2013-12-04T23:59:59.000Z

47

Homogeneous AlGaN/GaN superlattices grown on free-standing (1100) GaN substrates by plasma-assisted molecular beam epitaxy  

SciTech Connect

Two-dimensional and homogeneous growth of m-plane AlGaN by plasma-assisted molecular beam epitaxy has been realized on free-standing (1100) GaN substrates by implementing high metal-to-nitrogen (III/N) flux ratio. AlN island nucleation, often reported for m-plane AlGaN under nitrogen-rich growth conditions, is suppressed at high III/N flux ratio, highlighting the important role of growth kinetics for adatom incorporation. The homogeneity and microstructure of m-plane AlGaN/GaN superlattices are assessed via a combination of scanning transmission electron microscopy and high resolution transmission electron microscopy (TEM). The predominant defects identified in dark field TEM characterization are short basal plane stacking faults (SFs) bounded by either Frank-Shockley or Frank partial dislocations. In particular, the linear density of SFs is approximately 5 × 10{sup ?5} cm{sup ?1}, and the length of SFs is less than 15 nm.

Shao, Jiayi; Malis, Oana [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Zakharov, Dmitri N. [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973 (United States); Edmunds, Colin [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States)] [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Manfra, Michael J. [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 49707 (United States); School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 49707 (United States)

2013-12-02T23:59:59.000Z

48

Transmission electron microscopy studies of GaN/gamma-LiAlO 2 heterostructures.  

E-Print Network (OSTI)

??Die vorliegende Arbeit beschaeftigt sich mit dem strukturellen Aufbau von (1-100) M-plane GaN, das mit plasmaunterstuetzter Molekularstrahlepitaxie auf gamma-LiAlO2(100) Substraten gewachsen wurde. Die heteroepitaktische Ausrichtung… (more)

Liu, Tian-Yu

2005-01-01T23:59:59.000Z

49

Determination of subband energies and 2DEG characteristics of Al{sub x}Ga{sub 1?x}N/GaN heterojunctions using variational method  

SciTech Connect

A physics-based model based on the variational method for analyzing the two dimensional electron gas (2DEG) characteristics of polar AlGaN/GaN heterojunctions is developed. The 2DEG carrier concentration, the first and second energy subbands, and the position of the Fermi energy level are calculated for various barrier thicknesses, Al mole fractions, background dopant concentrations, and gate voltages for gated AlGaN/GaN heterojunctions. The results are in good agreement with the data reported based on self-consistent method. Whereas the aforementioned report has dealt with specific values of Al mole fraction, barrier thickness, and unintentional doping level, the present work provides a basis for calculating the 2DEG characteristics for the full range of these parameters. Furthermore, according to the proposed model, the applicability of the triangular approximation of the quantum well in AlGaN/GaN heterojunctions is evaluated.

Manouchehri, Farzin; Valizadeh, Pouya; Kabir, M. Z., E-mail: kabir@encs.concordia.ca [Department of Electrical and Computer Engineering, Concordia University, Montreal, H3G 1M8 (Canada)

2014-03-15T23:59:59.000Z

50

The crucial role of doping for high repetition rate monolithic mode locking of multiple quantum well GaAs/AlGaAs lasers  

E-Print Network (OSTI)

have been operated in GaAs/AlGaAs and InP/InGaAsP mul- tiple quantum well MQW materials showed no evidence of mode-locked operation. Band-edge absorption spectra are also presented which

51

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

52

Low threshold for optical damage in AlGaN epilayers and heterostructures  

SciTech Connect

Laser pulses with duration much shorter than the effective carrier lifetime cause permanent photoluminescence (PL) quenching and enhancement of PL decay rate in bare-faceted and capped AlGaN epilayers and multiple quantum wells at pulse energies about an order of magnitude lower than those causing the surface to melt and degrade. In contrast, GaN epilayers exhibit no photomodification in the same excitation intensity range. PL spectra and decay kinetics show that lattice heating is not responsible for the observed changes in AlGaN, which result from the formation of nonradiative recombination centers via recombination-enhanced defect reactions occurring at high nonequilibrium carrier densities.

Saxena, Tanuj [Department of ECSE, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Tamulaitis, Gintautas [Institute of Applied Research and Semiconductor Physics Department, Vilnius University, Sauletekio al. 9-III, Vilnius, LT-10222 (Lithuania); Shatalov, Max; Yang, Jinwei; Gaska, Remis [Sensor Electronic Technology, Inc., 1195 Atlas Road, Columbia, South Carolina 29209 (United States); Shur, Michael S. [Department of ECSE, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Department of PAPA, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2013-11-28T23:59:59.000Z

53

Simulation of Npn and Pnp AlGaN/GaN heterojunction bipolar transistors performances: Limiting factors and optimum design  

SciTech Connect

The performance capabilities of Npn and Pnp AlGaN/GaN heterojunction bipolar transistors have been investigated by using a drift-diffusion transport model. Numerical results have been employed to study the effect of the p-type Mg doping and its incomplete ionization on device performance. The high base resistance induced by the deep acceptor level is found to be the cause of limited current gain values for Npn devices. Several computation approaches have been considered to improve their performance. Reasonable improvement of the DC current gain {beta} is observed by realistically reducing the base thickness in accordance with processing limitations. Base transport enhancement is also predicted by the introduction of a quasi-electric field in the base. The impact of the base resistivity on high-frequency characteristics is investigated for Npn AlGaN/GaN devices. Optimized predictions with maximum oscillation frequency value as high as f{sub MAX} = 20 GHz and a unilateral power gain--U = 25 dB make this bipolar GaN-based technology compatible with communication applications. Simulation results reveal that the restricted amount of free carriers from the p-doped emitter limits Pnp's DC performances operating in common emitter configuration. A preliminary analysis of r.f. characteristics for the Pnp counterpart indicates limited performance mainly caused by the degraded hole mobility.

MONIER,C.; REN,F.; HAN,JUNG; CHANG,PING-CHIH; SHUL,RANDY J.; LEE,K.P.; ZHANG,A.P.; BACA,ALBERT G.; PEARTON,S.J.

2000-04-25T23:59:59.000Z

54

Tunneling and nonlinear transport in a vertically coupled GaAs/AlGaAs double quantum wire system.  

SciTech Connect

We report low-dimensional tunneling in an independently contacted vertically coupled quantum wire system. This nanostructure is fabricated in a high quality GaAs/AlGaAs parallel double quantum well heterostructure. Using a unique flip chip technique to align top and bottom split gates to form low-dimensional constrictions in each of the independently contacted quantum wells we explicitly control the subband occupation of the individual wires. In addition to the expected two-dimensional (2D)-2D tunneling results, we have found additional tunneling features that are related to the one-dimensional quantum wires.

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

2004-11-01T23:59:59.000Z

55

Dry patterning of InGaN and InAlN  

Science Journals Connector (OSTI)

Dry etch rates of In x Ga1?x N and In x Al1?x N alloys are found to increase with In mole fraction in CH4/H2microwave (2.45 GHz) discharges and to decrease under the same conditions in Cl2/H2 mixtures. Both plasma chemistries produce smooth anisotropicetching across the entire composition range from InN to either GaN or AlN. Addition of SF6 rather than H2 to a Cl2discharge produces faster etch rates and retains smooth morphologies. This suggests that either atomic hydrogen or fluorine is capable of effective removal of N from the III?V nitride materials. Ar+ ion milling rates for InGaAlN alloys are found to be approximately a factor of 2 lower than for more conventional III?V semiconductors like GaAs.

S. J. Pearton; C. R. Abernathy; F. Ren

1994-01-01T23:59:59.000Z

56

Molecular dynamics simulation comparison of atomic scale intermixing at the amorphous Al2O3/semiconductor interface for a-Al2O3/Ge, a-Al2O3/InGaAs,  

E-Print Network (OSTI)

Molecular dynamics simulation comparison of atomic scale intermixing at the amorphous Al2O3/semiconductor interface for a-Al2O3/Ge, a-Al2O3/InGaAs, and a-Al2O3/InAlAs/InGaAs Evgueni A. Chagarov *, Andrew oxides Ge InGaAs InAlAs Oxide­semiconductor stack High-K oxide a b s t r a c t The structural properties

Kummel, Andrew C.

57

Photodiode characteristics and band alignment parameters of epitaxial Al0.5Ga0.5P  

E-Print Network (OSTI)

Photodiode characteristics and band alignment parameters of epitaxial Al0.5Ga0.5P An Chen1,a-bandgap semiconductor AlxGa1-xP is a promising material candidate for low-noise photodiodes in blue/UV spectrum. Photodiodes were fabricated on Al0.5Ga0.5P epitaxial layer grown lattice matched on GaP substrate by molecular

Woodall, Jerry M.

58

Doping and isolation of GaN, InGaN and InAlN using ion implantation  

SciTech Connect

Both n- and p-type doping have been achieved in GaN using Si{sup +} or Mg{sup +}/P{sup +} implantation, respectively, followed annealing at {ge} 1050{degrees}C. Using proximity rapid thermal annealing (10sec) the GaN surface retains both smooth morphology and its original stoichiometry. Variable temperature Hall measurements reveal approximate energy levels of 62meV for the implanted Si and 171meV for the Mg, which are similar to their values in epitaxially grown GaN. Implant isolation of both n- and p-type GaN, and n-type In{sub 0.75}Al{sub 0.25}N with multiple energy inert species (e.g. N{sup +} or F{sup +}) produces high resistivity ({ge}10{sup 8}{omega}/{open_square}) after subsequent annealing in the range 600-700{degrees}C. Smaller increases in sheet resistance are observed for In{sub x}Ga{sup 1-x}N (x=0.33-0.75) under the same conditions due to the smaller energy bandgaps and the shallower energy levels of the damage-related states controlling the resistivity.

Pearton, S.J.; Vartuli, C.B.; Abernathy, C.R. [Univ. of Florida, Gainesville, FL (United States)] [and others

1995-08-01T23:59:59.000Z

59

Dependence on proton energy of degradation of AlGaN/GaN high electron mobility transistors  

SciTech Connect

The effects of proton irradiation energy on dc, small signal, and large signal rf characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated. AlGaN/GaN HEMTs were irradiated with protons at fixed fluence of 51015/cm2 and energies of 5, 10, and 15 MeV. Both dc and rf characteristics revealed more degradation at lower irradiation energy, with reductions of maximum transconductance of 11%, 22%, and 38%, and decreases in drain saturation current of 10%, 24%, and 46% for HEMTs exposed to 15, 10, and 5MeV protons, respectively. The increase in device degradation with decreasing proton energy is due to the increase in linear energy transfer and corresponding increase in nonionizing energy loss with decreasing proton energy in the active region of the HEMTs. After irradiation, both subthreshold drain leakage current and reverse gate current decreased more than 1 order of magnitude for all samples. The carrier removal rate was in the range 121 336 cm1 over the range of proton energies employed in this study

Liu, L. [University of Florida, Gainesville; Xi, Y. Y. [University of Florida, Gainesville; Wang, Y.l. [University of Florida; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Fitch, Robert C [Air Force Research Laboratory, Wright-Patterson AFB, OH; Walker, Dennis E [Air Force Research Laboratory, Wright-Patterson AFB, OH; Chabak, Kelson D [Air Force Research Laboratory, Wright-Patterson AFB, OH; Gillespie, James k [Air Force Research Laboratory, Wright-Patterson AFB, OH; Tetlak, Stephen E [Air Force Research Laboratory, Wright-Patterson AFB, OH; Via, Glen D [Air Force Research Laboratory, Wright-Patterson AFB, OH; Crespo, Antonio [Air Force Research Laboratory, Wright-Patterson AFB, OH; Kravchenko, Ivan I [ORNL

2013-01-01T23:59:59.000Z

60

Invited Paper AlGaN-based high-performance metalsemiconductormetal  

E-Print Network (OSTI)

combustion monitor- ing, furnace monitoring and missile warning; secure non-line-of-sight and space photodetector was demonstrated by Khan et al. [11] in 1993. Shortly after, the first AlGaN based solar that they are not responsive to the background radiation from the sun, since the solar radiation within their spectral band (l

Ozbay, Ekmel

Note: This page contains sample records for the topic "tn al ga" 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

NJ WY AK AL CA AR CO CT DE FL GA HI ID KS IL IN IA IA KY LA  

Gasoline and Diesel Fuel Update (EIA)

0.00-1.99 0.00-1.99 2.00-2.99 3.00-3.99 4.00-4.99 5.00-5.99 6.00-6.99 7.00+ NJ WY AK AL CA AR CO CT DE FL GA HI ID KS IL IN IA IA KY LA ME MI MA MD MN MS MT MO NE ND OH NV NM NY NH NC OK OR PA RI SC SD TN TX UT VT WA WV WI AZ VA DC 0.00-1.99 2.00-2.99 3.00-3.99 4.00-4.99 5.00-5.99 6.00-6.99 7.00+ 18. Average Price of Natural Gas Delivered to U.S. Onsystem Industrial Consumers, 1996 (Dollars per Thousand Cubic Feet) Figure 19. Average Price of Natural Gas Delivered to U.S. Electric Utilities, 1996 (Dollars per Thousand Cubic Feet) Figure Sources: Federal Energy Regulatory Commission (FERC), Form FERC-423, "Monthly Report of Cost and Quality of Fuels for Electric Plants," and Energy Information Administration (EIA), Form EIA-176, "Annual Report of Natural and Supplemental Gas Supply and Disposition." Note: In 1996, consumption of natural gas for agricultural use

62

Two-dimensional electron gases in strained quantum wells for AlN/GaN/AlN double heterostructure field-effect transistors on AlN  

SciTech Connect

Double heterostructures of strained GaN quantum wells (QWs) sandwiched between relaxed AlN layers provide a platform to investigate the quantum-confined electronic and optical properties of the wells. The growth of AlN/GaN/AlN heterostructures with varying GaN quantum well thicknesses on AlN by plasma molecular beam epitaxy (MBE) is reported. Photoluminescence spectra provide the optical signature of the thin GaN QWs. Reciprocal space mapping in X-ray diffraction shows that a GaN layer as thick as ?28 nm is compressively strained to the AlN layer underneath. The density of the polarization-induced two-dimensional electron gas (2DEG) in the undoped heterostructures increases with the GaN QW thickness, reaching ?2.5?×?10{sup 13}/cm{sup 2}. This provides a way to tune the 2DEG channel density without changing the thickness of the top barrier layer. Electron mobilities less than ?400 cm{sup 2}/Vs are observed, leaving ample room for improvement. Nevertheless, owing to the high 2DEG density, strained GaN QW field-effect transistors with MBE regrown ohmic contacts exhibit an on-current density ?1.4?A/mm, a transconductance ?280 mS/mm, and a cut off frequency f{sub T}?104?GHz for a 100-nm-gate-length device. These observations indicate high potential for high-speed radio frequency and high voltage applications that stand to benefit from the extreme-bandgap and high thermal conductivity of AlN.

Li, Guowang; Song, Bo; Ganguly, Satyaki; Zhu, Mingda; Wang, Ronghua; Yan, Xiaodong; Verma, Jai; Protasenko, Vladimir; Grace Xing, Huili; Jena, Debdeep, E-mail: djena@nd.edu [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2014-05-12T23:59:59.000Z

63

Carrier lifetime reduction in 1.5 m AlGaAsSb saturable absorbers with air and AlAsSb barriers  

E-Print Network (OSTI)

The SESAM structures consist of a 60-period InGaAsP/InP distributed Bragg reflector DBR and a 7-nm-thick Al exponential carrier decay time of 20 ps can be achieved. The studied AlGaAsSb absorbers were deposited on InGaAsP depth, the saturation fluence, the inverse absorption, the nonsaturable absorption, and the carrier de

Keller, Ursula

64

Vertical cavity surface emitting laser emitting at 1.56 microns with AlGaAsSb/AlAsSb distributed Bragg reflectors  

SciTech Connect

The authors report 77K operation of an optically pumped vertical cavity surface emitting laser with an Sb-based cavity. The structure consists of 15 and 20 pair AlGaAsSb/AlAsSb top and bottom reflectors and a bulk InGaAs active region.

Blum, O.; Klem, J.F.; Lear, K.L.; Vawter, G.A.; Kurtz, S.R.

1998-07-01T23:59:59.000Z

65

THz laser based on quasi-periodic AlGaAs superlattices  

SciTech Connect

The use of quasi-periodic AlGaAs superlattices as an active element of a quantum cascade laser of terahertz range is proposed and theoretically investigated. A multi-colour emission, having from three to six peaks of optical gain, is found in Fibonacci, Thue-Morse, and figurate superlattices in electric fields of intensity F = 11 - 13 kV cm{sup -1} in the frequency range f = 2 - 4 THz. The peaks depend linearly on the electric field, retain the height of 20 cm{sup -1}, and strongly depend on the thickness of the AlGaAs-layers. (lasers)

Malyshev, K V [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation)

2013-06-30T23:59:59.000Z

66

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

Science Journals Connector (OSTI)

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

T. Nakanishi; S. Nakamura

1991-01-01T23:59:59.000Z

67

GaAs/AlGaAs nanostructured composites for free-space and integrated optical devices  

E-Print Network (OSTI)

after development with MIBK:IPA=1:2 for 2min. Different fillon GaAs developed with MIBK:IPA=1:2 for (a) 1 min; (b) 2d) shows a nonoptimized developer, MIBK:IPA=2:1, used for 3

Tsai, Chia-Ho

2006-01-01T23:59:59.000Z

68

Time-resolved photoluminescence, positron annihilation, and Al0.23Ga0.77N/GaN heterostructure growth studies on low defect density polar and nonpolar freestanding GaN substrates grown by hydride vapor phase epitaxy  

Science Journals Connector (OSTI)

Time-resolved photoluminescence(TRPL) and positron annihilation measurements as well as Al0.23Ga0.77N/GaN heterostructuregrowth by metalorganic vapor phase epitaxy were carried out on very low defect density polar c-plane and nonpolar m-plane freestanding GaN (FS-GaN) substrates grown by hydride vapor phase epitaxy. Room-temperature photoluminescence(PL) lifetime for the near-band-edge (NBE) excitonic emission of the FS-GaN substrates increases with increasing positron diffusion length (L +); i.e. decreasing gross concentration of charged and neutral point defects and complexes. The best undoped c-plane FS-GaN exhibits record-long L + being 116?nm. The fast component of the PL lifetime for its NBE emission increases with temperature rise up to 100?K and levels off at approximately 1.1?ns. The result implies a saturation in thermal activation of nonradiative recombination centers. The surface and interface roughnesses for a Si-doped Al0.23Ga0.77N/GaN/Al0.18Ga0.82N/GaN heterostructure are improved by the use of FS-GaN substrates in comparison with the structure fabricated on a standard GaN template. The emission signals related to the recombination of a two-dimensional electron gas and excited holes are recognized for an Al0.23Ga0.77N/GaN single heterostructuregrown on the c-plane FS-GaN substrate.

S. F. Chichibu; K. Hazu; Y. Ishikawa; M. Tashiro; H. Namita; S. Nagao; K. Fujito; A. Uedono

2012-01-01T23:59:59.000Z

69

Spectral research on an AlGaAs epitaxial material for a terahertz quantum-cascade laser  

Science Journals Connector (OSTI)

The spectral properties of a series of AlGaAs epitaxial films were studied by using a Fourier transform infrared spectrometer with an 80-degree grazing incidence reflection unit. The AlAs-like transversal optical...

Zhi-Yong Tan; Jun-Cheng Cao

2012-04-01T23:59:59.000Z

70

FIRST DEMONSTRATION OF MONOLITHIC InP-BASED InAlAs/InGaAsP/InGaAs TRIPLE JUNCTION SOLAR CELLS  

E-Print Network (OSTI)

FIRST DEMONSTRATION OF MONOLITHIC InP-BASED InAlAs/InGaAsP/InGaAs TRIPLE JUNCTION SOLAR CELLS Robyn C. Law 1 1 Spectrolab, Inc., A Boeing Company, Sylmar, California 91342, USA 2 California Institute of Technology, Pasadena, California 91125, USA ABSTRACT Spectrolab has demonstrated the first lattice matched In

Atwater, Harry

71

Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics  

Science Journals Connector (OSTI)

An n++-GaAs/p++-AlGaAs tunnel junction with a peak current density of 10?100 A cm?2 is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10?000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500 A cm?2 and a voltage drop at 10?000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations.

I García; I Rey-Stolle; C Algora

2012-01-01T23:59:59.000Z

72

Growth mechanisms of GaSb heteroepitaxial films on Si with an AlSb buffer layer  

SciTech Connect

The initial growth stages of GaSb epilayers on Si substrates and the role of the AlSb buffer layer were studied by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Heteroepitaxy of GaSb and AlSb on Si both occur by Volmer-Weber (i.e., island mode) growth. However, the AlSb and GaSb islands have distinctly different characteristics as revealed through an atomic-resolution structural study using Z-contrast of HAADF-STEM imaging. While GaSb islands are sparse and three dimensional, AlSb islands are numerous and flattened. The introduction of 3D island-forming AlSb buffer layer facilitates the nucleation of GaSb islands. The AlSb islands-assisted nucleation of GaSb islands results in the formation of drastically higher quality planar film at a significantly smaller thickness of films. The interface of the AlSb and GaSb epilayers with the Si substrate was further investigated with energy dispersive X-ray spectrometry to elucidate the key role of the AlSb buffer layer in the growth of GaSb epilayers on Si substrates.

Vajargah, S. Hosseini; Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada) [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Canadian Centre for Electron Microscopy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Ghanad-Tavakoli, S. [Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada)] [Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Preston, J. S.; Kleiman, R. N. [Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1 (Canada) [Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Centre for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L7 (Canada)

2013-09-21T23:59:59.000Z

73

Violet to deep-ultraviolet InGaN/GaN and GaN/AlGaN quantum structures for UV electroabsorption modulators  

E-Print Network (OSTI)

focused on the demonstration of ultraviolet UV optoelectronic devices. Such devices hold promise, material related problems complicate the growth of such optoelectronic devices oper- ating at short wavelengths. With the use of InGaN/GaN quantum structures, optoelectronic devices operating in vis- ible

Demir, Hilmi Volkan

74

Effect of Mg ionization efficiency on performance of Npn AlGaN/GaN heterojunction bipolar transistors  

SciTech Connect

A drift-diffusion transport model has been used to examine the performance capabilities of AlGaN/GaN Npn heterojunction bipolar transistors (HBTs). The Gummel plot from the first GaN-based HBT structure recently demonstrated is adjusted with simulation by using experimental mobility and lifetime reported in the literature. Numerical results have been explored to study the effect of the p-type Mg doping and its incomplete ionization in the base. The high base resistance induced by the deep acceptor level is found to be the cause of limiting current gain values. Increasing the operating temperature of the device activates more carriers in the base. An improvement of the simulated current gain by a factor of 2 to 4 between 25 and 300 C agrees well with the reported experimental results. A preliminary analysis of high frequency characteristics indicates substantial progress of predicted rf performances by operating the device at higher temperature due to a reduced extrinsic base resistivity.

MONIER,C.; PEARTON,S.J.; CHANG,PING-CHIH; BACA,ALBERT G.

2000-03-10T23:59:59.000Z

75

Characterization of interface states in Al{sub 2}O{sub 3}/AlGaN/GaN structures for improved performance of high-electron-mobility transistors  

SciTech Connect

We have investigated the relationship between improved electrical properties of Al{sub 2}O{sub 3}/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) and electronic state densities at the Al{sub 2}O{sub 3}/AlGaN interface evaluated from the same structures as the MOS-HEMTs. To evaluate Al{sub 2}O{sub 3}/AlGaN interface state densities of the MOS-HEMTs, two types of capacitance-voltage (C-V) measurement techniques were employed: the photo-assisted C-V measurement for the near-midgap states and the frequency dependent C-V characteristics for the states near the conduction-band edge. To reduce the interface states, an N{sub 2}O-radical treatment was applied to the AlGaN surface just prior to the deposition of the Al{sub 2}O{sub 3} insulator. As compared to the sample without the treatment, the N{sub 2}O-radical treated Al{sub 2}O{sub 3}/AlGaN/GaN structure showed smaller frequency dispersion of the C-V curves in the positive gate bias range. The state densities at the Al{sub 2}O{sub 3}/AlGaN interface were estimated to be 1?×?10{sup 12}?cm{sup ?2}?eV{sup ?1} or less around the midgap and 8?×?10{sup 12}?cm{sup ?2}?eV{sup ?1} near the conduction-band edge. In addition, we observed higher maximum drain current at the positive gate bias and suppressed threshold voltage instability under the negative gate bias stress even at 150?°C. Results presented in this paper indicated that the N{sub 2}O-radical treatment is effective both in reducing the interface states and improving the electrical properties of the Al{sub 2}O{sub 3}/AlGaN/GaN MOS-HEMTs.

Hori, Y.; Yatabe, Z. [Research Center for Integrated Quantum Electronics (RCIQE) and Graduate School of Information Science and Technology, Hokkaido University, North 13 West 8, Sapporo, 060-8628 Hokkaido (Japan); Hashizume, T., E-mail: hashi@rciqe.hokudai.ac.jp [Research Center for Integrated Quantum Electronics (RCIQE) and Graduate School of Information Science and Technology, Hokkaido University, North 13 West 8, Sapporo, 060-8628 Hokkaido (Japan); Japan Science and Technology Agency (JST), CREST, Tokyo 102-0075 (Japan)

2013-12-28T23:59:59.000Z

76

Dislocation-induced fields in piezoelectric AlGaN/GaN bimaterial heterostructures  

E-Print Network (OSTI)

and energy conversion abil- ity between mechanical and electric fields, providing opportuni- ties-implanted AlN J. Appl. Phys. 112, 073525 (2012) Minimum energy structures of faceted, incoherent interfaces J. Appl. Phys. 112, 073501 (2012) Defect specific photoconductance: Carrier recombination through surface

Pan, Ernie

77

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

Science Journals Connector (OSTI)

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

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

1990-01-01T23:59:59.000Z

78

Journal of Crystal Growth 293 (2006) 273277 A study of semi-insulating GaN grown on AlN buffer/sapphire  

E-Print Network (OSTI)

-temperature GaN interlayer. In comparison with the normal GaN grown on sapphire, the crystal quality measurement results of GaN grown directly on an AlN buffer indicated that the as-grown-undoped Ga, or high density of edge-type dislocations [6­10]. However, Fe and other heavy metals tend to have reactor

Ozbay, Ekmel

79

In situ chemical sensing in AlGaN/GaN high electron mobility transistor metalorganic chemical vapor deposition process for real-time  

E-Print Network (OSTI)

; accepted 14 June 2005; published 18 July 2005 Gallium nitride and its alloys promise to be key materials.1116/1.1993616 I. INTRODUCTION In recent years, gallium-nitride GaN - and aluminum- gallium-nitride AlGaN -based are grown at high temperatures e.g., up to 1100 °C using large concentrations of H2 carrier and NH3 N source

Rubloff, Gary W.

80

Composition dependent valence band order in c-oriented wurtzite AlGaN layers  

SciTech Connect

The valence band order of polar wurtzite aluminum gallium nitride (AlGaN) layers is analyzed for a dense series of samples, grown heteroepitaxially on sapphire substrates, covering the complete composition range. The excitonic transition energies, found by temperature dependent photoluminescence (PL) spectroscopy, were corrected to the unstrained state using input from X-ray diffraction. k?p theory yields a critical relative aluminum concentration x{sub c}=(0.09±0.05) for the crossing of the uppermost two valence bands for strain free material, shifting to higher values for compressively strained samples, as supported by polarization dependent PL. The analysis of the strain dependent valence band crossing reconciles the findings of other research groups, where sample strain was neglected. We found a bowing for the energy band gap to the valence band with ?{sub 9} symmetry of b{sub ?{sub 9}}=0.85eV, and propose a possible bowing for the crystal field energy of b{sub cf}=?0.12eV. A comparison of the light extraction efficiency perpendicular and parallel to the c axis of Al{sub x}Ga{sub 1-x}N/Al{sub y}Ga{sub 1-y}N quantum well structures is discussed for different compositions.

Neuschl, B., E-mail: benjamin.neuschl@uni-ulm.de; Helbing, J.; Knab, M.; Lauer, H.; Madel, M.; Thonke, K. [Institute of Quantum Matter / Semiconductor Physics Group, University of Ulm, Albert-Einstein-Allee 45, 89069 Ulm (Germany); Meisch, T.; Forghani, K.; Scholz, F. [Institute of Optoelectronics, University of Ulm, Albert-Einstein-Allee 45, 89069 Ulm (Germany); Feneberg, M. [Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)

2014-09-21T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Magnetotransport studies of AlGaN/GaN heterostructures with two-dimensional electron gas in parallel with a three-dimensional Al-graded layer: Incorrect hole type determination  

Science Journals Connector (OSTI)

We report magnetotransport measurements performed on AlGaN/GaN devices with different buffer layers. Standard samples with a 1??m thick GaN buffer show a linear Hall resistance and an almost constant magnetoresistance as expected from a single two-dimensional electron gas (2DEG) at the AlGaN/GaN interface. Other samples with an Al x Ga1– x N buffer (x?=?5%) and a buried linear aluminium gradient have an additional three-dimensional electron slab (3DES) close to the GaN substrate. In this case the Hall resistance is strongly non-linear and presents an incorrect hole-type carrier signature evidenced by low field mobility spectrum analysis. This effect is strengthened when the 3D layer parallel to the mesa-etched 2DEG is infinite. We suggest that the misplacement of the electrical contacts in the 3DES i.e. far from the sample edges could explain the wrong carrier type determination.

L. Konczewicz

2013-01-01T23:59:59.000Z

82

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

Science Journals Connector (OSTI)

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

Ken T. Park and Y. Gao

1993-02-15T23:59:59.000Z

83

Determination of gain in AlGaN cladding free nitride laser diodes  

SciTech Connect

The optical gain spectra of InGaN-based multiple-quantum-well (MQW) laser diodes (LDs) grown by plasma-assisted molecular beam epitaxy are compared for different emission wavelengths. Two AlGaN cladding free LDs with similar epitaxial structures but with different In compositions in MQW were grown to study the dependence of material gain on lasing wavelength. As the emission wavelength increased from 432 to 458 nm, the differential modal gain decreased from 5.7 to 4.7 cm/kA, and the optical losses increased from 40 to 46 cm{sup ?1} resulting in an increase in threshold current density. This dependence is attributed to lower optical mode confinement of LD emitting at longer wavelength. We found a strong decrease of confinement factor with increasing wavelength.

Muziol, G.; Turski, H.; Wolny, P. [Institute of High Pressure Physics, Sokolowska 29/37, 01-142 Warsaw (Poland)] [Institute of High Pressure Physics, Sokolowska 29/37, 01-142 Warsaw (Poland); Siekacz, M.; Sawicka, M.; Perlin, P.; Skierbiszewski, C. [Institute of High Pressure Physics, Sokolowska 29/37, 01-142 Warsaw (Poland) [Institute of High Pressure Physics, Sokolowska 29/37, 01-142 Warsaw (Poland); TopGaN Ltd, ul Soko?owska 29/37, 01-142 Warszawa (Poland)

2013-08-05T23:59:59.000Z

84

Journal of Crystal Growth 195 (1998) 309--313 Structural and optical properties of AlInN and AlGaInN  

E-Print Network (OSTI)

and cladding layers in quantum well (QW) laser diode (LD) structures, respectively [1--3]. In contrast, little- ful: Al In N can be lattice-matched to GaN; consequently, Al \\V In V N can be used as a cladding

Wetzel, Christian M.

85

Influence of composition and heat treatment on damping and magnetostrictive properties of Fe-18%(Ga+Al) alloys  

SciTech Connect

The structure, magnetostriction and damping properties of Fe82Ga(18?x)Alx(x = 0, 5, 8, 12) alloys were analyzed. The anelastic response of Fe–18(Ga + Al) alloys was studied as a function of temperature (from 0 to 600 ?C), frequency (from 0.01 to 200 Hz) and amplitude (from 0.0004% to 0.2%) of forced vibrations. The origin of the relatively high damping capacity of Fe–Ga–Al alloy at room temperature was determined by applying a magnetic field and different heat treatment regimes. The substitution of Ga by Al in Fe–18% Ga alloys was found to decrease magnetostriction and damping. The heat treatment of alloys influences the damping capacity of alloys more than variations of their chemical compositions. Thermally activated frequency and temperature-dependent anelastic effects in Fe– Ga–Al alloys were analyzed and the corresponding activation parameters for relaxation processes were evaluated. Internal friction effects caused by structural transformations were recorded and were found to be consistent with the A2 ! D03! L12reaction. The physical mechanisms for all anelastic effects are discussed

Golovin, I S [National University of Science and Technology MISIS; Palacheva, V V [National University of Science and Technology MISIS; Zadorozhnyy, V Yu [National University of Science and Technology MISIS; Zhu, J [University of Science and Technology Beijing; Jiang, H [University of Science and Technology Beijing; Cifre, J [Universitat de les Illes Balears; Lograsso, Thomas A [Ames Laboratory

2014-10-01T23:59:59.000Z

86

Effect of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content AlGaN quantum well lasers  

E-Print Network (OSTI)

of high Al-content AlGaN quantum well lasers Jing Zhang, Hongping Zhao, and Nelson Tansu Citation: Appl of crystal-field split-off hole and heavy-hole bands crossover on gain characteristics of high Al-content Al characteristics of high Al-content AlGaN quantum wells QWs are analyzed for deep UV lasers. The effect of crystal

Gilchrist, James F.

87

Growth and electrical characterization of Al{sub 0.24}Ga{sub 0.76}As/Al{sub x}Ga{sub 1-x}As/Al{sub 0.24}Ga{sub 0.76}As modulation-doped quantum wells with extremely low x  

SciTech Connect

We report on the growth and electrical characterization of modulation-doped Al{sub 0.24}Ga{sub 0.76}As/Al{sub x}Ga{sub 1-x}As/Al{sub 0.24}Ga{sub 0.76}As quantum wells with mole fractions as low as x = 0.00057. Such structures will permit detailed studies of the impact of alloy disorder in the fractional quantum Hall regime. At zero magnetic field, we extract an alloy scattering rate of 24 ns{sup -1} per%Al. Additionally, we find that for x as low as 0.00057 in the quantum well, alloy scattering becomes the dominant mobility-limiting scattering mechanism in ultra-high purity two-dimensional electron gases typically used to study the fragile {nu} = 5/2 and {nu} = 12/5 fractional quantum Hall states.

Gardner, Geoffrey C. [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Watson, John D.; Mondal, Sumit [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States); Deng, Nianpei; Csathy, Gabor A. [Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States)] [Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States); Manfra, Michael J. [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States) [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States); School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2013-06-24T23:59:59.000Z

88

First principles calculation of polarization induced interfacial charges in GaN/AlN heterostructures  

E-Print Network (OSTI)

We propose a new method to calculate polarization induced interfacial charges in semiconductor heterostructures using classical electrostatics applied to real-space band diagrams from first principles calculations and apply it to GaN/AlN heterostructures with ultrathin AlN layers (4-6 monolayers). We show that the calculated electric fields and interfacial charges are independent of the exchange-correlation functionals used (local-density approximation and hybrid functionals). We also find the calculated interfacial charge of (6.8 +/- 0.4) x 10^13 cm-2 to be in excellent agreement with experiments and the value of 6.58 x 10^13 cm-2 calculated from bulk polarization constants, validating the use of bulk constants even for very thin films.

Rohan Mishra; Oscar D. Restrepo; Siddharth Rajan; Wolfgang Windl

2011-05-17T23:59:59.000Z

89

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

Science Journals Connector (OSTI)

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

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

90

Si-CMOS-Like Integration of AlGaN/GaN Dielectric-Gated High-Electron-Mobility Transistors  

E-Print Network (OSTI)

the engineering of high mobility, high carrier density channels at III-Nitride heterointerfaces. In order to seize market share from silicon, the cost of manufacturing GaN-based devices must be further reduced. With the successful realization of 200mm GaN-on-Si...

Johnson, Derek Wade

2014-07-31T23:59:59.000Z

91

US ESC TN Site Consumption  

U.S. Energy Information Administration (EIA) Indexed Site

ESC TN ESC TN Site Consumption million Btu $0 $500 $1,000 $1,500 $2,000 $2,500 US ESC TN Expenditures dollars ALL ENERGY average per household (excl. transportation) 0 4,000 8,000 12,000 16,000 US ESC TN Site Consumption kilowatthours $0 $400 $800 $1,200 $1,600 US ESC TN Expenditures dollars ELECTRICITY ONLY average per household * Tennessee households consume an average of 79 million Btu per year, about 12% less than the U.S. average. * Average electricity consumption for Tennessee households is 33% higher than the national average and among the highest in the nation, but spending for electricity is closer to average due to relatively low electricity prices. * Tennessee homes are typically newer, yet smaller in size, than homes in other parts of the country.

92

Mid-infrared pump-related electric-field domains in GaAs/(Al,Ga)As quantum-cascade structures for terahertz lasing without population inversion  

SciTech Connect

We investigate the effect of mid-infrared (MIR) pumping on the transport properties of GaAs/(Al,Ga)As terahertz (THz) quantum lasers (TQLs), which rely on quantum coherence effects of intersubband transitions. Aiming at THz lasing at elevated temperatures, we extend the concept of THz gain with and without population inversion of a single, MIR-pumped, electrically driven THz stage proposed by Waldmueller et al.[Phys. Rev. Lett. 99, 117401 (2007)] to an entire TQL. However, experiments using a CO{sub 2} as well as a free-electron laser and numerical simulations show that this resonant MIR pumping causes a negative differential conductivity (NDC) in addition to the NDC caused by sequential tunneling. Lasing of these TQLs is prevented by the formation of electric-field domains below the resonance field strength for gain of each single THz stage.

Giehler, M.; Wienold, M.; Schrottke, L.; Hey, R.; Grahn, H. T. [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Pavlov, S. G. [Deutsches Zentrum fuer Luft- und Raumfahrt, Rutherfordstr. 2, 12489 Berlin (Germany); Huebers, H.-W. [Deutsches Zentrum fuer Luft- und Raumfahrt, Rutherfordstr. 2, 12489 Berlin (Germany); Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Winnerl, S.; Schneider, H. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany)

2011-11-15T23:59:59.000Z

93

Metalorganic vapor phase epitaxy and characterizations of nearly-lattice-matched AlInN alloys on GaN/sapphire templates and  

E-Print Network (OSTI)

InN material lattice-matched to GaN will also be useful as cladding layer in laser structure. Specifically, Al) for solid state light- ing [1­19], visible diode lasers for both display and biosensing [20GaN and AlGaN in III-nitride based applications for LEDs [40­42] and laser diode (LD) [20­26], solar

Gilchrist, James F.

94

Low-frequency noise in Al0.4Ga0.6N-based Schottky barrier photodetectors S. L. Rumyantsev,a)  

E-Print Network (OSTI)

as the carrier gas. The n -Al0.4Ga0.6N layer was codoped using disilane (Si2H4) and TMI. As confirmed n -Al0.4Ga0.6N active layer grown with the disilane flux reduced by a factor of 10. The C

Pala, Nezih

95

Catalyst performance of novel Pt/Mg(Ga)(Al)O catalysts for alkane dehydrogenation Georges Siddiqi, Pingping Sun, Vladimir Galvita, Alexis T. Bell *  

E-Print Network (OSTI)

Catalyst performance of novel Pt/Mg(Ga)(Al)O catalysts for alkane dehydrogenation Georges Siddiqi dehydrogenation Pt Hydrotalcite a b s t r a c t The dehydrogenation of ethane and propane using a Pt catalyst supported on a novel Mg(Ga)(Al)O mixed oxide support was investigated. Catalyst performance is strongly

Bell, Alexis

96

Transport mechanism of ?- and X-band electrons in AlxGa1-xAs/AlAs/GaAs double-barrier quantum-well infrared photodetectors  

Science Journals Connector (OSTI)

The effect of the ?- and X-band electrons in the Al0.25Ga0.75As/AlAs/GaAs double-barrier quantum well (DBQW) is investigated by a microscopic empirical pseudopotential calculation. The DBQW structure used in the calculation is designed as a 3–5-?m quantum-well infrared photodetector with an associated transition energy of 313 meV. DBQW tunneling transmission via ?- and X-like states as a function of electron energy and applied voltage are described and compared to that in a single-barrier AlAs/GaAs quantum well. The dark current is simulated by the confined ground-state electron tunneling out of the well. We find that, at high-bias voltage, tunneling via X-like states increases the current by a few orders of magnitude. We have also varied the additional barrier thickness and found that for a very thin (<20 Å) additional barrier DBQW, the excited-state electrons are not blocked by the ?-band barrier, and may give a high photocurrent without the assistance of the X band, although the dark current also increases. © 1996 The American Physical Society.

T. Osotchan; V. W. L. Chin; T. L. Tansley

1996-07-15T23:59:59.000Z

97

Synthesis of Nb/sub 3/Ga and Nb/sub 3/Al superconducting composites by laser beam irradiation  

SciTech Connect

Nb/sub 3/Ga and Nb/sub 3/Al superconductors were successfully fabricated by continuous CO/sub 2/ laser beam irradiation of a moving material. Transition temperatures after the irradiation are 17.0 and 16.5 K, respectively. These temperatures are increased by approx.2 K by the subsequent annealings. Critical current density J/sub c/ (for the reacted area) of 3 x 10/sup 4/ A/cm/sup 2/ at 15 T and 4.2 K is obtained for Nb/sub 3/Al tape with small magnetic field dependence up to 23 T. The results indicate that the continuous laser beam irradiation is a very attractive method for fabricating advanced superconductors, such as Nb/sub 3/Ga, Nb/sub 3/Al, Nb/sub 3/(Al,Ge), etc.

Kumakura, H.; Togano, K.; Tachikawa, K.; Yamada, Y.; Murase, S.; Nakamura, E.; Sasaki, M.

1986-03-03T23:59:59.000Z

98

Investigation of interface intermixing and roughening in low-temperature-grown AlAs/GaAs multiple quantum wells  

E-Print Network (OSTI)

Investigation of interface intermixing and roughening in low-temperature-grown AlAs/GaAs multiple to the standard-temperature-grown MQW. However, significant interface roughening and intermixing occurs- neal ambients14 have effects on interface roughening or in- termixing. In all cases, enhanced diffusion

Woodall, Jerry M.

99

A Millimeter-wave Harmonic Optoelectronic Mixer based on InAlAs/InGaAs Metamorphic HEMT  

E-Print Network (OSTI)

A Millimeter-wave Harmonic Optoelectronic Mixer based on InAlAs/InGaAs Metamorphic HEMT ChangAs substrate as a harmonic optoelectronic mixer. The fabricated metamorphic HEMT simultaneously performs photodetection at 1.55µµµµm lightwave and harmonic optoelectronic up-conversion into millimeter-wave band

Choi, Woo-Young

100

Vacancy diffusion kinetics in arsenic-rich nonstoichiometric AlAsGaAs heterostructures S. Balasubramanian and S. W. Mansour  

E-Print Network (OSTI)

Vacancy diffusion kinetics in arsenic-rich nonstoichiometric AlAsÃ?GaAs heterostructures S. The intermixing is attributed to a supersaturated concentration of group-III vacancies and is enhanced by several temperatures. In this paper we establish that the decay of the excess vacancy concentration satisfies second

Nolte, David D.

Note: This page contains sample records for the topic "tn al ga" 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

Direct measurements of large near-band edge nonlinear index change from 1.48 to 1.55 m in InGaAsInAlGaAs multiquantum wells  

E-Print Network (OSTI)

used to measure di- rectly the nonlinear index change in bulk InGaAsP.10 Com- parison of DFWM results measurements of nonlinear refractive index change and nonlinear absorption in In0.530Al0.141Ga0.329As/In0.530Ga . The index-change-over-absorption figure of merit, F, is greater than unity over much of the spectrum

102

Cross-plane lattice and electronic thermal conductivities of ErAs:InGaAs/InGaAlAs superlattices  

E-Print Network (OSTI)

of thermoelectric energy conversion devices depends on the thermoelectric figure of merit ZT of a material, which- troduced charge carriers in the ErAs:InGaAs regions of 0, 2 1018 , 4 1018 , and 8 1018 cm-3 , respectively. There- fore, the effective carrier concentrations in the four samples were 2 1018 , 4 1018 , 6 1018

103

Narrow spectral linewidth of single zinc-blende GaN/AlN self-assembled quantum dots  

SciTech Connect

We study by microphotoluminescence the optical properties of single self-assembled zinc-blende GaN/AlN quantum dots grown by plasma-assisted molecular beam epitaxy. As opposed to previous reports, the high quality of such zinc-blende GaN quantum dots allows us to evidence a weak acoustic phonon sideband as well as a limited spectral diffusion. As a result, we report on resolution-limited quantum dot linewidths as narrow as 500 ± 50 ?eV. We finally confirm the fast radiative lifetime and high-temperature operation of such quantum dots.

Sergent, S. [Institute for Nano Quantum Information Electronics, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)] [Institute for Nano Quantum Information Electronics, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Kako, S. [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)] [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Bürger, M.; As, D. J. [Department Physik, Universität Paderborn, Warburger Str. 100, 33098 Paderborn (Germany)] [Department Physik, Universität Paderborn, Warburger Str. 100, 33098 Paderborn (Germany); Arakawa, Y. [Institute for Nano Quantum Information Electronics, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan) [Institute for Nano Quantum Information Electronics, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)

2013-10-07T23:59:59.000Z

104

Current collapse imaging of Schottky gate AlGaN/GaN high electron mobility transistors by electric field-induced optical second-harmonic generation measurement  

SciTech Connect

Two-dimensional current collapse imaging of a Schottky gate AlGaN/GaN high electron mobility transistor device was achieved by optical electric field-induced second-harmonic generation (EFISHG) measurements. EFISHG measurements can detect the electric field produced by carriers trapped in the on-state of the device, which leads to current collapse. Immediately after (e.g., 1, 100, or 800??s) the completion of drain-stress voltage (200?V) in the off-state, the second-harmonic (SH) signals appeared within 2??m from the gate edge on the drain electrode. The SH signal intensity became weak with time, which suggests that the trapped carriers are emitted from the trap sites. The SH signal location supports the well-known virtual gate model for current collapse.

Katsuno, Takashi, E-mail: e1417@mosk.tytlabs.co.jp; Ishikawa, Tsuyoshi; Ueda, Hiroyuki; Uesugi, Tsutomu [Toyota Central R and D Laboratories Inc., Nagakute, Aichi 480-1192 (Japan); Manaka, Takaaki; Iwamoto, Mitsumasa [Department of Physical Electronics, Tokyo Institute of Technology, Meguro, Tokyo 152-8552 (Japan)

2014-06-23T23:59:59.000Z

105

Category:Memphis, TN | Open Energy Information  

Open Energy Info (EERE)

Memphis, TN Memphis, TN Jump to: navigation, search Go Back to PV Economics By Location Media in category "Memphis, TN" The following 16 files are in this category, out of 16 total. SVFullServiceRestaurant Memphis TN City of Memphis Tennessee (Utility Company).png SVFullServiceRestauran... 66 KB SVHospital Memphis TN City of Memphis Tennessee (Utility Company).png SVHospital Memphis TN ... 69 KB SVLargeHotel Memphis TN City of Memphis Tennessee (Utility Company).png SVLargeHotel Memphis T... 67 KB SVLargeOffice Memphis TN City of Memphis Tennessee (Utility Company).png SVLargeOffice Memphis ... 70 KB SVMediumOffice Memphis TN City of Memphis Tennessee (Utility Company).png SVMediumOffice Memphis... 65 KB SVMidriseApartment Memphis TN City of Memphis Tennessee (Utility Company).png

106

Effects of built-in internal fields and Al alloy content on donor binding energy of a hydrogenic impurity in a wurtzite GaN/AlGaN quantum dot  

Science Journals Connector (OSTI)

Built-in internal field induced donor hydrogenic binding energy of an impurity in a wurtzite GaN/AlGaN quantum dot is investigated. The built-in internal electric field has the contribution from spontaneous and piezo-electric polarisation. The computations are carried out with the inclusion of conduction band non-parabolicity through the energy dependent effective mass. It is calculated with a variational approach within the framework of single band effective-mass approximation. A two-parametric trial wave function is employed in order to improve the results. The effects of quantum confinement and the strength of internal electric fields on the donor binding energy are discussed. The results show that the strength of the internal field is of the order MV/cm and it has more influence on the geometrical confinement and the composition of Al alloy content in the GaN/AlxGa1-xN quantum dot. These results are in good agreement with the other investigators.

M. Pattammal; A. John Peter

2014-01-01T23:59:59.000Z

107

Structure and zero-dimensional polariton spectrum of natural defects in GaAs/AlAs microcavities  

Science Journals Connector (OSTI)

We present a correlative study of structural and optical properties of natural defects in planar semiconductor microcavities grown by molecular beam epitaxy, which are showing a localized polariton spectrum as reported in Zajac et al. [Phys. Rev. B 85, 165309 (2012)]. The three-dimensional spatial structure of the defects was studied using combined focused ion beam (FIB) and scanning electron microscopy (SEM). We find that the defects originate from a local increase of a GaAs layer thickness. Modulation heights of up to 140 nm for oval defects and 90 nm for round defects are found, while the lateral extension is about 2 ?m for oval and 4 ?m for round defects. The GaAs thickness increase is attributed to a Ga droplet deposited during growth due to Ga cell spitting. Following the droplet deposition, the thickness modulation expands laterally while reducing its height, yielding oval to round mounds of the interfaces and the surface. With increasing growth temperature, the ellipticity of the mounds is decreasing and their size is increasing. This suggests that the expansion is related to the surface mobility of Ga, which, with increasing temperature, is increasing and reducing its anisotropy between the [110] and [11¯0] crystallographic directions. Comprehensive data consisting of surface profiles of defects measured using differential interference contrast microscopy, volume information obtained using FIB/SEM, and characterization of the resulting confined polariton spectrum are presented.

Joanna M. Zajac and Wolfgang Langbein

2012-11-01T23:59:59.000Z

108

Successes and failures of the k?p method: A direct assessment for GaAs/AlAs quantum structures  

Science Journals Connector (OSTI)

The k?p method combined with the envelope-function approximation is the tool most commonly used to predict electronic properties of semiconductor quantum wells and superlattices. We test this approach by comparing band energies, dispersion, and wave functions for GaAs/AlAs superlattices and quantum wells as computed directly from a pseudopotential band structure and using eight-band k?p. To assure equivalent inputs, all parameters needed for the k?p treatment are extracted from calculated bulk GaAs and AlAs pseudopotential band structures. Except for large exchange splittings in the in-plane dispersion for thin superlattices, present in pseudopotential calculations but absent from the k?p results, we find generally good agreement for heterostructure hole bands within ?200 meV of the GaAs valence-band maximum. There are systematic errors in band energies and dispersion for deeper hole bands (all other than hh1 and lh1) and significant qualitative and quantitative errors for the conduction bands. Errors for heterostructure conduction states which are derived from the zinc-blende ? point diminish as length scales increase beyond ?20 ML, while significant errors persist for L- and X-derived states.For bulk GaAs and AlAs, eight-band k?p bands agree well with pseudopotential results very near the zinc-blende ? point (where k?p parameters are fit) but the first GaAs X point conduction band is ?26 eV too high with respect to the pseudopotential result. We show that this inadequate description of the bulk band dispersion is the principal source of k?p errors in these heterostructures. A wave-function projection analysis shows that k?p errors for heterostructures simply reflect corresponding errors for the bulk constituents, weighted by the amount that such bulk states participate in heterostructure states. © 1996 The American Physical Society.

D. M. Wood and Alex Zunger

1996-03-15T23:59:59.000Z

109

High photo-excited carrier multiplication by charged InAs dots in AlAs/GaAs/AlAs resonant tunneling diode  

E-Print Network (OSTI)

We present an approach for the highly sensitive photon detection based on the quantum dots (QDs) operating at temperature of 77K. The detection structure is based on an AlAs/GaAs/AlAs double barrier resonant tunneling diode combined with a layer of self-assembled InAs QDs (QD-RTD). A photon rate of 115 photons per second had induced 10nA photocurrent in this structure, corresponding to the photo-excited carrier multiplication factor of 10^7. This high multiplication factor is achieved by the quantum dot induced memory effect and the resonant tunneling tuning effect of QD-RTD structure.

Wangping Wang; Ying Hou; Dayuan Xiong; Ning Li; Wei Lu

2007-10-15T23:59:59.000Z

110

High?quality focused?ion?beam?made mirrors for InGaP/InGaAlP visible?laser diodes  

Science Journals Connector (OSTI)

We employed a focused ion beam(FIB) to sputter the end mirrors on InGaP/InGaAlP laser diodes. This particular diode operates at a wavelength of about 670 nm. For this wavelength the quality of the sputteredmirrors is far more critical than for longer wavelength devices. The present lasers do in fact show a relatively large increase in their threshold current after FIBmicromachining. In this article we investigate the origins of this increase and how to prevent it. After optimization the lasers with a FIB?made end mirror have a threshold current comparable to that of cleaved?facet devices. We have seen that the polycrystalline structure of the device metallization on top of the laser diode causes roughening of the mirror during sputtering which results in severe scatter losses of the laser light. A method to decrease the surface roughness is given. A further reason for the increase in threshold current is optical absorption at the mirror presumably by a Ga?rich layer. This can be circumvented by chemical etching after FIB treatment to remove the absorbing layer. Finally to demonstrate the quality and the applicability of the FIB?made mirrors the influence of the tilt angle of the end mirror on the threshold current of the laser has been investigated. This dependency can be excellently described by theory.

M. H. F. Overwijk; J. A. de Poorter

1993-01-01T23:59:59.000Z

111

Category:Nashville, TN | Open Energy Information  

Open Energy Info (EERE)

Nashville, TN Nashville, TN Jump to: navigation, search Go Back to PV Economics By Location Media in category "Nashville, TN" The following 16 files are in this category, out of 16 total. SVFullServiceRestaurant Nashville TN City of Memphis Tennessee (Utility Company).png SVFullServiceRestauran... 67 KB SVHospital Nashville TN City of Memphis Tennessee (Utility Company).png SVHospital Nashville T... 71 KB SVLargeHotel Nashville TN City of Memphis Tennessee (Utility Company).png SVLargeHotel Nashville... 68 KB SVLargeOffice Nashville TN City of Memphis Tennessee (Utility Company).png SVLargeOffice Nashvill... 71 KB SVMediumOffice Nashville TN City of Memphis Tennessee (Utility Company).png SVMediumOffice Nashvil... 67 KB SVMidriseApartment Nashville TN City of Memphis Tennessee (Utility Company).png

112

Electronic structure of Al- and Ga-doped ZnO films studied by hard X-ray photoelectron spectroscopy  

SciTech Connect

Al- and Ga-doped sputtered ZnO films (AZO, GZO) are semiconducting and metallic, respectively, despite the same electronic valence structure of the dopants. Using hard X-ray photoelectron spectroscopy we observe that both dopants induce a band in the electronic structure near the Fermi level, accompanied by a narrowing of the Zn 3d/O 2p gap in the valence band and, in the case of GZO, a substantial shift in the Zn 3d. Ga occupies substitutional sites, whereas Al dopants are in both substitutional and interstitial sites. The latter could induce O and Zn defects, which act as acceptors explaining the semiconducting character of AZO and the lack of variation in the optical gap. By contrast, mainly substitutional doping is consistent with the metallic-like behavior of GZO.

Gabás, M.; Ramos Barrado, José R. [Lab. de Materiales and Superficies, Dpto. de Física Aplicada I, Universidad de Málaga, 29071 Málaga (Spain); Torelli, P. [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, I-34149 Trieste (Italy); Barrett, N. T. [CEA, DSM/IRAMIS/SPCSI, F-91191 Gif-sur-Yvette Cedex (France); Sacchi, M. [Synchrotron SOLEIL, BP 48, 91192 Gif-sur-Yvette, France and Institut des NanoSciences de Paris, UPMC Paris 06, CNRS UMR 7588, 4 Place Jussieu, 75005 Paris (France)

2014-01-01T23:59:59.000Z

113

Cl{sub 2}-based dry etching of the AlGaInN system in inductively coupled plasmas  

SciTech Connect

Cl{sub 2}-based Inductively Coupled Plasmas with low additional dc self- biases(-100V) produce convenient etch rates(500-1500 A /min) for GaN, AlN, InN, InAlN and InGaN. A systematic study of the effects of additive gas(Ar, N{sub 2}, H{sub 2}), discharge composition and ICP source power and chuck power on etch rate and surface morphology has been performed. The general trends are to go through a maximum in etch rate with percent Cl{sub 2} in the discharge for all three mixtures, and to have an increase(decrease) in etch rate with source power(pressure). Since the etching is strongly ion-assisted, anisotropic pattern transfer is readily achieved. Maximum etch selectivities of approximately 6 for InN over the other nitrides were obtained.

Cho, Hyun; Vartuli, C.B.; Abernathy, C.R.; Donovan, S.M.; Pearton, S.J. [Florida Univ., Gainesville, FL (United States). Dept. of Materials Science and Engineering; Shul, R.J.; Han, J. [Sandia National Labs., NM (United States)

1997-12-01T23:59:59.000Z

114

Inductively coupled plasma–reactive ion etching of c- and a-plane AlGaN over the entire Al composition range: Effect of BCl{sub 3} pretreatment in Cl{sub 2}/Ar plasma chemistry  

SciTech Connect

Inductively coupled plasma (ICP)–reactive ion etching (RIE) patterning is a standard processing step for UV and optical photonic devices based on III-nitride materials. There is little research on ICP-RIE of high Al-content AlGaN alloys and for nonpolar nitride orientations. The authors present a comprehensive study of the ICP-RIE of c- and a-plane AlGaN in Cl{sub 2}/Ar plasma over the entire Al composition range. The authors find that the etch rate decreases in general with increasing Al content, with different behavior for c- and a-plane AlGaN. They also study the effect of BCl{sub 3} deoxidizing plasma pretreatment. An ICP deoxidizing BCl{sub 3} plasma with the addition of argon is more efficient in removal of surface oxides from Al{sub x}Ga{sub 1?x}N than RIE alone. These experiments show that Al{sub x}Ga{sub 1?x}N etching is affected by the higher binding energy of AlN and the higher affinity of oxygen to aluminum compared to gallium, with oxides on a-plane AlGaN more difficult to etch as compared to oxides on c-plane AlGaN, specifically for high Al composition materials. The authors achieve reasonably high etch rate (?350 nm/min) for high Al-content materials with a smooth surface morphology at a low DC bias of ??45 VDC.

Shah, Amit P.; Laskar, Masihhur R.; Azizur Rahman, A.; Gokhale, Maheshwar R.; Bhattacharya, Arnab [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)] [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India)

2013-11-15T23:59:59.000Z

115

Nanocomposites of Semimetallic ErAs Nanoparticles Epitaxially Embedded within InGaAlAs-based Semiconductors for Thermoelectric Materials  

E-Print Network (OSTI)

GaAlAs-based Semiconductors for Thermoelectric Materials J.M.O. Zide', G. Zeng2, J.H. Bahk2, W. Kim3, S. L. Singer3, D array based on these materials for thermoelectric power generation; a power density > 1 W/cm2 is demonstrated with a temperature gradient of 120°C. Solid-state thermionics Efficient thermoelectric materials

116

Wafer-scale surface roughening for enhanced light extraction of high power AlGaInP-based light-emitting diodes  

Science Journals Connector (OSTI)

A new approach to surface roughening was established and optimized in this paper for enhancing the light extraction of high power AlGaInP-based LEDs, by combining ultraviolet (UV)...

Park, Hyeong-Ho; Zhang, Xin; Cho, Yunae; Kim, Dong-Wook; Kim, Joondong; Lee, Keun Woo; Choi, Jehyuk; Lee, Hee Kwan; Jung, Sang Hyun; Her, Eun Jin; Kim, Chang Hwan; Moon, A-Young; Shin, Chan-Soo; Shin, Hyun-Beom; Sung, Ho Kun; Park, Kyung Ho; Park, Hyung-Ho; Kim, Hi-Jung; Kang, Ho Kwan

2014-01-01T23:59:59.000Z

117

1718 IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 16, NO. 7, JULY 2004 Solar-Blind AlGaN-Based p-i-n Photodiodes With  

E-Print Network (OSTI)

-i-n Photodiodes With Low Dark Current and High Detectivity N. Biyikli, I. Kimukin, O. Aytur, and E. Ozbay Abstract--We report solar-blind Al Ga1 N-based heterojunc- tion p-i-n photodiodes with low dark current and high. Index Terms--AlGaN, dark current, detectivity, heterostruc- ture, high-performance, p-i-n photodiode

Aytür, Orhan

118

In this paper, an AlGaN/GaN high electron mobility transistor (HEMT) device based on a  

E-Print Network (OSTI)

field-plate (IFP) HEMT structure is simulated by using the two-dimensional device simulator (SILVACO and Simulation The two-dimensional device simulator used in this work was SILVACO Atlas. The structure of the Al

Yang, Kyounghoon

119

Inductively Coupled Plasma and Electron Cyclotron Resonance Plasma Etching of InGaAlP Compound Semiconductor System  

SciTech Connect

Current and future generations of sophisticated compound semiconductor devices require the ability for submicron scale patterning. The situation is being complicated since some of the new devices are based on a wider diversity of materials to be etched. Conventional IUE (Reactive Ion Etching) has been prevalent across the industry so far, but has limitations for materials with high bond strengths or multiple elements. IrI this paper, we suggest high density plasmas such as ECR (Electron Cyclotron Resonance) and ICP (Inductively Coupled Plasma), for the etching of ternary compound semiconductors (InGaP, AIInP, AlGaP) which are employed for electronic devices like heterojunction bipolar transistors (HBTs) or high electron mobility transistors (HEMTs), and photonic devices such as light-emitting diodes (LEDs) and lasers. High density plasma sources, opeiating at lower pressure, are expected to meet target goals determined in terms of etch rate, surface morphology, surface stoichiometry, selectivity, etc. The etching mechanisms, which are described in this paper, can also be applied to other III-V (GaAs-based, InP-based) as well as III-Nitride since the InGaAIP system shares many of the same properties.

Abernathy, C.R.; Hobson, W.S.; Hong, J.; Lambers, E.S.; Pearton, S.J.; Shul, R.J.

1998-11-04T23:59:59.000Z

120

Surface barrier height for different Al compositions and barrier layer thicknesses in AlGaN/GaN heterostructure field effect transistors  

SciTech Connect

In this paper, we present a physics based analytical model for the calculation of surface barrier height for given values of barrier layer thicknesses and Al mole fractions. An explicit expression for the two dimensional electron gas density is also developed incorporating the change in polarization charges for different Al mole fractions.

Goyal, Nitin, E-mail: goyalnitin.iitr@gmail.com; Fjeldly, Tor A. [Norwegian University of Science and Technology, Trondheim (Norway); Iniguez, Benjamin [Universitat Rovira i Virgili, Tarragona (Spain)

2013-12-04T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Terahertz absorption in AlGaAs films and detection using heterojunctions  

E-Print Network (OSTI)

a Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA b NDP Optronics, LLC-mail address: uperera@gsu.edu (A.G.U. Perera). 1 Also at NDP Optronics LLC. Infrared Physics & Technology 47

Perera, A. G. Unil

122

Photodiode characteristics and band alignment parameters of epitaxial Al{sub 0.5}Ga{sub 0.5}P  

SciTech Connect

Wide-bandgap semiconductor Al{sub x}Ga{sub 1-x}P is a promising material candidate for low-noise photodiodes in blue/UV spectrum. Photodiodes were fabricated on Al{sub 0.5}Ga{sub 0.5}P epitaxial layer grown lattice matched on GaP substrate by molecular beam epitaxy. Although quantum efficiency is low for standard p-i-n photodiode due to inadvertent photon absorption in the top p-layer, it can be significantly improved by opening a recessed window in the top p-layer or by using a Schottky junction photodiode structure. Al{sub 0.5}Ga{sub 0.5}P band alignment parameters can be extrapolated from the current-voltage characteristics of Al{sub 0.5}Ga{sub 0.5}P Schottky junctions. The bandgap of Al{sub 0.5}Ga{sub 0.5}P was measured to be 2.38 eV.

Chen An [Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511 (United States); Woodall, Jerry M. [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2009-01-12T23:59:59.000Z

123

Investigation of the negative differential resistance reproducibility in AlN/GaN double-barrier resonant tunnelling diodes  

SciTech Connect

AlN/GaN double-barrier resonant tunnelling diodes were grown by molecular beam epitaxy on GaN/sapphire template and processed into mesa diameters from 2 {mu}m to 4 {mu}m. The current-voltage characteristics were carried out in direct current operation and under-high vacuum. A sharp negative differential resistance (NDR) was detected in the forward bias at 120 K. The NDR was observed for the mesa size of 2 {mu}m at 4 V with a peak-to-valley current ratio of 3.5. The measurement conditions were chosen to make NDR reproducible more than 50 times and apparent in both scan voltage directions after electrical treatment.

Boucherit, M.; Soltani, A.; Rousseau, M.; Deresmes, D.; Berthe, M.; Durand, C.; De Jaeger, J.-C. [IEMN/UMR-CNRS 8520, Universite Lille1, PRES Universite Lille Nord de France (France); Monroy, E. [Equipe mixte CEA-CNRS-UJF Nanophysique et Semiconducteurs, DRFMC/SP2M/PSC, CEA-Grenoble (France)

2011-10-31T23:59:59.000Z

124

The two-qubit controlled-phase gate based on cross-phase modulation in GaAs/AlGaAs semiconductor quantum wells  

E-Print Network (OSTI)

We present a realization of two-qubit controlled-phase gate, based on the linear and nonlinear properties of the probe and signal optical pulses in an asymmetric GaAs/AlGaAs double quantum wells. It is shown that, in the presence of cross-phase modulation, a giant cross-Kerr nonlinearity and mutually matched group velocities of the probe and signal optical pulses can be achieved while realizing the suppression of linear and self-Kerr optical absorption synchronously. These characteristics serve to exhibit an all-optical two-qubit controlled-phase gate within efficiently controllable photon-photon entanglement by semiconductor mediation. In addition, by using just polarizing beam splitters and half-wave plates, we propose a practical experimental scheme to discriminate the maximally entangled polarization state of two-qubit through distinguishing two out of the four Bell states. This proposal potentially enables the realization of solid states mediated all-optical quantum computation and information processing.

X. Q. Luo; D. L. Wang; H. Fan; W. M. Liu

2012-01-17T23:59:59.000Z

125

Variations of energies and line shapes of the electroreflectance spectra of epitaxial Al x Ga1?x As  

Science Journals Connector (OSTI)

The electrolyte electroreflectance (EER) spectra of Al x Ga1?x As have been obtained in the E 0 and E 1 regions and for Al concentrations ranging from x=0 to 0.65. From the spectra obtained under low field conditions the variations of the interband energies with Al concentrations have been established. Following Aspnes [Surf. Sci. 3 7 419 (1973)] we have made detailed analyses of the complex resonance line shapes of the experimentally observed modulated reflectance spectra. The parameters ? and E g have been calculated and these have been used to generate theoretically the spectra for comparison with experimental results. In addition we have also examined the effects of dc bias on the EER spectra. Variations of E 0 E 0+?0 E 1 and E 1+?1 have been discussed and results on the line?shape parameters have been presented.

J. M. Wrobel; L. C. Bassett; J. L. Aubel; S. Sundaram; John L. Davis; James Comas

1987-01-01T23:59:59.000Z

126

X-ray induced persistent photoconductivity in Si-doped Al0.35Ga0.65As Yeong-Ah Soha)  

E-Print Network (OSTI)

X-ray induced persistent photoconductivity in Si-doped Al0.35Ga0.65As Yeong-Ah Soha) and G. Aeppli for publication 14 August 2001 We demonstrate that x-ray irradiation can be used to induce an insulator with fluorescence. The photoconductance as a function of incident x-ray energy exhibits an edge both at the Ga

Frenkel, Anatoly

127

Difference-frequency generation in AlGaAs Bragg reflection waveguides  

E-Print Network (OSTI)

-matching (BPM) [5,6] and quasi-phase-matching [7,8]. Among these, BPM has been shown to be the most efficient with the absorption of GaAs below 870 nm in wavelength, limits the operating window of BPM devices for infrared

128

GaInAs/AlInAs quantum cascade laser design based on optimized second harmonic generation  

Science Journals Connector (OSTI)

In this work, we present an innovative procedure for the design and optimization of GaInAs/AlInAs quantum cascade laser (QCL) structures based on the use of the genetic algorithm. The purpose of the algorithm is to determine the set of design parameters that would enable the maximization of the second order nonlinear susceptibility, thus facilitating significant optical nonlinearities to take place. In our optimization model, we start from the existing design in which the active region consists of two coupled InGaAs quantum wells separated by an AlInAs barrier, and the active region levels form double resonant nonlinear cascades. Upon obtaining the optimized structure and evaluating its energies and wave functions, the output characteristics are calculated by applying the full self-consistent rate equation modeling of the electron transport in a periodic QCL structure. The results of the calculations predict a noticeable improvement of targeted properties of the optimized design, while at the same time the original design calculations show excellent agreement with experimental results. The described procedure is applicable to various active region designs and can be used for other wavelength ranges.

A Gaji?; J Radovanovi?; V Milanovi?; D Indjin; Z Ikoni?

2014-01-01T23:59:59.000Z

129

Quantitative compositional analysis and strain study of InAs quantum wires with InGaAlAs barrier layers  

SciTech Connect

Quantitative compositional analysis of InAs quantum wires deposited between In{sub 0.53}Ga{sub 0.37}Al{sub 0.1}As barrier layers grown on InP substrates was performed by electron energy loss spectrometry and energy dispersive x-ray spectrometry. An indium-rich region in the center of the wire, with decreasing indium concentration toward the interface with the barrier layers, was observed from indium concentration maps for individual quantum wires. 'Stripelike' contrast modulation was observed in diffraction contrast transmission electron microscope images of the In{sub 0.53}Ga{sub 0.37}Al{sub 0.1}As barrier layer immediately above the quantum wires. The contrast originated from indium compositional modulations in the upper barrier layer as confirmed by electron energy loss spectrometry and the modulation is attributed to the presence of an inhomogeneous elastic strain field generated by the buried quantum wires. These results suggest that quantitative analysis of the composition and strain distributions at very high spatial resolution provides insights necessary to further model the physical properties and to understand the growth of these nanostructures.

Cui, K. [Department of Materials Science and Engineering, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Robertson, M. D. [Department of Physics, Acadia University, Wolfville, NS, B4P 2R6 (Canada); Robinson, B. J. [Center for Emerging Device Technologies, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Andrei, C. M. [Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Thompson, D. A. [Center for Emerging Device Technologies, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Department of Engineering Physics, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, ON, L8S 4L7 (Canada); Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, L8S 4L7 (Canada)

2009-05-01T23:59:59.000Z

130

Effects of proton irradiation on dc characteristics of InAlN/GaN high electron mobility transistors  

SciTech Connect

The effects of proton irradiation on the dc characteristics of InAlN/GaN high electron mobility transistors were investigated. In this study we used 5 MeV protons with doses varying from 21011 to 21015 cm2. The transfer resistance and contact resistivity suffered more degradation as compared to the sheet resistance. With irradiation at the highest dose of 21015 cm2, both forward- and reverse-bias gate currents were increased after proton irradiation. A negative threshold-shift and reduction of the saturation drain current were also observed as a result of radiation-induced carrier scattering and carrier removal. Devices irradiated with doses of 21011 to 21015 cm2 exhibited minimal degradation of the saturation drain current and extrinsic trans- conductance. These results show that InAlN/GaN high electron mobility transistors are attractive for space-based applications when high-energy proton fluxes are present. VC 2011 American Vacuum Society. [DOI: 10.1116/1.3644480

Lo, C. F. [University of Florida; Liu, L. [University of Florida, Gainesville; Ren, F. [University of Florida; Kim, H.-Y. [Korea University; Kim, J. [Korea University; Pearton, S. J. [University of Florida; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL

2011-01-01T23:59:59.000Z

131

Murdock Road Knoxville.TN  

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

702 702 Murdock Road Knoxville.TN 37932 Tel: (609) 921-1456 Fax: (609) 92 1-8703 AA\W.nell-one.com March 25,2009 Office of the Assistant General Counsel for Technology Transfer and Intellectual Property U.S. Department of Energy 1000 Independence Avenue, SW Washington, DC 20585 Attn: Technology Transfer Questions Subject: Questions Concerning Technology Transfer Practices at DOE Laboratories (Federal RegisterNol. 73, No. 229/ November 26,2008 /Notices) Dear Mr. Gottlieb, Thank you for the opportunity to respond to the questions published in the Federal Register. As Chief Executive Officer of Nell One Therapeutics, a spin-out company which is in the process of licensing technology from Oak Ridge National Laboratory (ORNL), I found the questions to be highly relevant to our experiences. While many great technologies and capabilities reside in the National Laboratories

132

Electron effective mass in Al{sub 0.72}Ga{sub 0.28}N alloys determined by mid-infrared optical Hall effect  

SciTech Connect

The effective electron mass parameter in Si-doped Al{sub 0.72}Ga{sub 0.28}N is determined to be m{sup ?}=(0.336±0.020)?m{sub 0} from mid-infrared optical Hall effect measurements. No significant anisotropy of the effective electron mass parameter is found supporting theoretical predictions. Assuming a linear change of the effective electron mass with the Al content in AlGaN alloys and m{sup ?}=0.232?m{sub 0} for GaN, an average effective electron mass of m{sup ?}=0.376?m{sub 0} can be extrapolated for AlN. The analysis of mid-infrared spectroscopic ellipsometry measurements further confirms the two phonon mode behavior of the E{sub 1}(TO) and one phonon mode behavior of the A{sub 1}(LO) phonon mode in high-Al-content AlGaN alloys as seen in previous Raman scattering studies.

Schöche, S., E-mail: schoeche@huskers.unl.edu; Kühne, P.; Hofmann, T.; Schubert, M. [Department of Electrical Engineering and CNFM, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588-0511 (United States)] [Department of Electrical Engineering and CNFM, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588-0511 (United States); Nilsson, D.; Kakanakova-Georgieva, A.; Janzén, E.; Darakchieva, V. [Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 581 83 (Sweden)] [Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 581 83 (Sweden)

2013-11-18T23:59:59.000Z

133

Characterization of ultraviolet excited Br * ?radical etching of InGaAs/InAlAs material system  

Science Journals Connector (OSTI)

Dry selective photochemicaletching of InGaAs/InAlAs material system in HBr gas excited by a 172 nm excimer lamp has been characterized. The etching is thought to be due to the formation of reactive Br*?radicals which are photocreated in the gas phase and then diffused into the solid semiconductor to create volatile products. The etching is temperature sensitive with best etching results at 50–110°?C. Atomic force microscope and scanning electron microscope pictures reveal that the surface morphology at this temperature range is smooth and fine. Auger electron spectroscopy and x?ray photoelectron spectroscopy measurements show that at low temperatures the etch products are primarily salts of bromide and are in the liquid phase and thus remain at the surface and a desorption process stops further etching. At slightly elevated temperature range the creation of oxides and deposition of bromine compounds reduces the etch rate and causes the surface quality to deteriorate. Etching at higher pressure range increases the etch rate of InGaAs but results in surface quality deterioration.

Soheil Habibi; Jun Tanaka; Hideki Hattori; Masahiro Totsuka; Satoru Matsumoto

1996-01-01T23:59:59.000Z

134

Influence of confined phonon modes on the thermal behavior of AlAs/GaAs quantum cascade structures  

Science Journals Connector (OSTI)

The thermal behavior of AlAs/GaAs quantum cascade structures is used to demonstrate the existence of confined and interface optical-phonon modes. The high conduction-band offset of this material system greatly improves the confinement of the electronic states and allows the realization of electroluminescence structures, where the optical power as a function of the temperature solely depends on the change of the upper-state lifetime induced by the longitudinal-optical-phonon population. We observed that the latter is proportional to the Bose-Einstein factor, with an appropriate phonon mode energy, which does not simply correspond to that of the GaAs bulk phonon (36-meV energy). In particular we show that the agreement between theory and experiment can be substantially improved when the confined and interface modes are taken into account in our calculation. Our results are corroborated by the threshold temperature dependence of lasers, with an active region based on similar structures.

C. Becker; C. Sirtori; H. Page; A. Robertson; V. Ortiz; X. Marcadet

2002-01-30T23:59:59.000Z

135

Large area supersonic jet epitaxy of AlN, GaN, and SiC on silicon  

SciTech Connect

AlN, GaN, and SiC thin films were grown on 100 mm diameter Si(111) and Si(100) substrates using Supersonic Jet Epitaxy (SJE). Precursor gases were seeded in lighter mass carrier gases and free jets were formed using novel slit-jet apertures. The jet design, combined with substrate rotation, allowed for a uniform flux distribution over a large area of a 100 mm wafer at growth pressures of 1--20 mTorr. Triethylaluminum, triethylgallium, and ammonia were used for nitride growth, while disilane, acetylene, and methylsilane were used for SiC growth. The films were characterized by in situ optical reflectivity, x-ray diffraction (XRD), atomic force microscopy (AFM), and spectroscopic ellipsometry (SE).

Lauhon, L.J.; Ustin, S.A.; Ho, W. [Cornell Univ., Ithaca, NY (United States). Dept. of Physics

1997-12-31T23:59:59.000Z

136

Modulation spectroscopy of the complex photoluminescence band of Ga0.7Al0.3As:Si  

Science Journals Connector (OSTI)

The photoluminescence and reflectivity of Ga0.7Al0.3As:Si have been studied in piezomodulation, wavelength-modulation, and photomodulation spectroscopy at low temperatures. We could identify the symmetry of the zero-phonon and phonon-assisted transitions by their comparative behavior in wavelength- and piezomodulated spectroscopy. The experimental results have been interpreted in the framework of an effective-mass model of the donor wave function in multivalley semiconductors similar to that proposed by Henning, Ansems, and Roksnoer [Semicond. Sci. Technol. 3, 361 (1988)]. Within this model, a value of the hydrostatic deformation potential of the L band in this alloy is deduced: -4.99±0.07 eV.

B. Gil, M. Leroux, J. P. Contour, and C. Chaix

1991-05-15T23:59:59.000Z

137

Radio-frequency measurements of UNiX compounds (X= Al, Ga, Ge) in high magnetic fields  

SciTech Connect

We performed radio-frequency (RF) skin-depth measurements of antiferromagnetic UNiX compounds (X=Al, Ga, Ge) in magnetic fields up to 60 T and at temperatures between 1.4 to {approx}60 K. Magnetic fields are applied along different crystallographic directions and RF penetration-depth was measured using a tunnel-diode oscillator (TDO) circuit. The sample is coupled to the inductive element of a TDO resonant tank circuit, and the shift in the resonant frequency {Delta}f of the circuit is measured. The UNiX compounds exhibit field-induced magnetic transitions at low temperatures, and those transitions are accompanied by a drastic change in {Delta}f. The results of our skin-depth measurements were compared with previously published B-T phase diagrams for these three compounds.

Mielke, Charles H [Los Alamos National Laboratory; Mcdonald, David R [Los Alamos National Laboratory; Zapf, Vivien [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Lacerda, Alex H [Los Alamos National Laboratory; Adak, Sourav [Los Alamos National Laboratory; Karunakar, Kothapalli [Los Alamos National Laboratory; Nakotte, Heinrich [Los Alamos National Laboratory; Chang, S [NIST; Alsmadi, A M [HASHEMITE UNIV; Alyones, S [HASHEMIT UNIV

2009-01-01T23:59:59.000Z

138

Comparison of dipole layers, band offsets, and formation enthalpies of GaAs-AlAs(110) and (001) interfaces  

Science Journals Connector (OSTI)

We report a very careful, self-consistent, relativistic pseudopotential calculation of the interfacial dipole double-layer potential, valence-band offset, and formation enthalpy of (GaAs)3(AlAs)3(110). A comparison is made with identical calculations for the (001) superlattice with the following results [(001) in parentheses]: The interfacial dipole layer is 315 (154) meV. The formation enthalpy per twelve-atom unit cell is -21.9 (+1.7) meV. The valence-band offset is 447 (446) meV. This lends credence to the idea that the band offset is a difference of bulk quantities and that vastly different interfaces set up whatever double layer is necessary to maintain that difference.

D. M. Bylander and Leonard Kleinman

1987-11-02T23:59:59.000Z

139

Direct and indirect exciton states in GaAs-(Ga, Al)As double quantum wells under crossed electric and magnetic fields  

Science Journals Connector (OSTI)

A theoretical study of the direct and indirect exciton states in GaAs/Ga1-xAlxAs coupled double quantum wells under crossed electric and magnetic fields is presented. The setup of the system under consideration consists of an ... Keywords: 71.55.Eq, 73.20.Mf, 73.21.Fg, Diamagnetic shifts, Double quantum-wells, Magnetoexcitons

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

2008-03-01T23:59:59.000Z

140

AlGaN UV LED and Photodiodes Radiation Hardness and Space Qualifications and Their Applications in Space Science and High Energy Density Physics  

SciTech Connect

This presentation provides an overview of robust, radiation hard AlGaN optoelectronic devices and their applications in space exploration & high energy density physics. Particularly, deep UV LED and deep UV photodiodes are discussed with regard to their applications, radiation hardness and space qualification. AC charge management of UV LED satellite payload instruments, which were to be launched in late 2012, is covered.

Sun, K. X.

2011-05-31T23:59:59.000Z

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


141

Selectivity in the conversion of n-heptane on an Al-PILC modified with Ga  

Science Journals Connector (OSTI)

This work compares the catalytic activity for the hydroisomerization and hydrocracking of n-heptane for two pillared clay materials, one with polyoxycations of Al and the other with the same cation modified by...

Carmen Pesquera; Fernando González…

1995-06-01T23:59:59.000Z

142

Two dimensional electron transport in modulation-doped In{sub 0.53}Ga{sub 0.47}As/AlAs{sub 0.56}Sb{sub 0.44} ultrathin quantum wells  

SciTech Connect

We have investigated the growth and electron transport in In{sub 0.53}Ga{sub 0.47}As/AlAs{sub 0.56}Sb{sub 0.44} two dimensional electron gases (2DEG) and compared their properties with In{sub 0.53}Ga{sub 0.47}As/In{sub 0.52}Al{sub 0.48}As 2DEGs. For 10?nm thick InGaAs wells, the electron mobility of InGaAs/AlAsSb 2DEGs is comparable to that of InGaAs/InAlAs 2DEGs. Upon thinning the wells to 3?nm, the 2DEG mobility is degraded quickly and stronger interface roughness scattering is observed for InGaAs/AlAsSb heterointerfaces than for InGaAs/InAlAs heterointerfaces. Changing the group-V exposure between As and Sb during growth interruptions at the InGaAs/AlAsSb interfaces did not significantly change the 2DEG mobility. With the insertion of a two monolayer InAlAs at the InGaAs/AlAsSb interfaces, the interface roughness scattering is reduced and the mobility greatly increased. The room temperature 2DEG mobility shows 66% improvement from 1.63?×?10{sup 3} cm{sup 2}/V·s to 2.71?×?10{sup 3}?cm{sup 2}/V·s for a 3?nm InGaAs well.

Huang, Cheng-Ying, E-mail: cyhuang@ece.ucsb.edu; Law, Jeremy J. M.; Rodwell, Mark J. W. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Lu, Hong; Gossard, Arthur C. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Materials Department, University of California, Santa Barbara, California 93106-5050 (United States); Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2014-03-28T23:59:59.000Z

143

Solar Hot Water Market Development in Knoxville, TN | Department...  

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

Information Resources Solar Hot Water Market Development in Knoxville, TN Solar Hot Water Market Development in Knoxville, TN Assessment of local solar hot water markets, market...

144

Study of the interface of undoped and p?doped ZnSe with GaAs and AlAs  

Science Journals Connector (OSTI)

We have used electrolyte electroreflectance (EER) to characterize ZnSe/GaAs and ZnSe/AlAs interfaces. The great sensitivity of EER to interface space?charge regions enabled us to detect both interface crossover transitions and transitions to triangular?well interface states. The observation of these transitions provides the first unambiguous proof that the ZnSe/GaAs interface is type I and allowed us to determine the band offsets and band bendings the diffusion lengths across each interface and the amount of interdiffusion.

L. Kassel; H. Abad; J. W. Garland; P. M. Raccah; J. E. Potts; M. A. Haase; H. Cheng

1990-01-01T23:59:59.000Z

145

X-ray determination of threading dislocation densities in GaN/Al{sub 2}O{sub 3}(0001) films grown by metalorganic vapor phase epitaxy  

SciTech Connect

Densities of a- and a+c-type threading dislocations for a series of GaN films grown in different modes by metalorganic vapor phase epitaxy are determined from the x-ray diffraction profiles in skew geometry. The reciprocal space maps are also studied. Theory of x-ray scattering from crystals with dislocations is extended in order to take into account contribution from both threading and misfit dislocations. The broadening of the reciprocal space maps along the surface normal and the rotation of the intensity distribution ellipse is attributed to misfit dislocations at the interface. We find that the presence of a sharp AlN/GaN interface leads to an ordering of misfit dislocations and reduces strain inhomogeneity in GaN films.

Kopp, Viktor S., E-mail: victor.kopp@pdi-berlin.de; Kaganer, Vladimir M. [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5–7, 10117 Berlin (Germany); Baidakova, Marina V.; Lundin, Wsevolod V.; Nikolaev, Andrey E.; Verkhovtceva, Elena V.; Yagovkina, Maria A. [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, 194021 St.-Petersburg (Russian Federation); Cherkashin, Nikolay [CEMES-CNRS and Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse (France)

2014-02-21T23:59:59.000Z

146

GaN High Power Devices  

SciTech Connect

A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers, GaN/AlGaN heterojunction bipolar transistors, GaN heterostructure and metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.

PEARTON,S.J.; REN,F.; ZHANG,A.P.; DANG,G.; CAO,X.A.; LEE,K.P.; CHO,H.; GILA,B.P.; JOHNSON,J.W.; MONIER,C.; ABERNATHY,C.R.; HAN,JUNG; BACA,ALBERT G.; CHYI,J.-I.; LEE,C.-M.; NEE,T.-E.; CHUO,C.-C.; CHI,G.C.; CHU,S.N.G.

2000-07-17T23:59:59.000Z

147

DOE - Office of Legacy Management -- Knoxville Iron Co - TN 07  

Office of Legacy Management (LM)

Knoxville Iron Co - TN 07 Knoxville Iron Co - TN 07 FUSRAP Considered Sites Site: KNOXVILLE IRON CO. (TN.07 ) Eliminated from consideration under FUSRAP Designated Name: Not Designated Alternate Name: None Location: Knoxville , Tennessee TN.07-1 Evaluation Year: 1994 TN.07-2 TN.07-3 Site Operations: Melted uranium contaminated scrap metal in order to test industrial hygiene procedures in the mid-1950s. TN.07-1 Site Disposition: Eliminated - AEC license TN.07-2 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Limited Quantities of Uranium Contained in Slag Material TN.07-4 Radiological Survey(s): Yes - health and safety monitoring during operations only TN.07-4 Site Status: Eliminated from consideration under FUSRAP Also see Documents Related to KNOXVILLE IRON CO.

148

Above room-temperature operation of InAs/AlGaSb superlattice quantum cascade lasers emitting at 12 {mu}m  

SciTech Connect

The authors report on above-room-temperature operation of InAs/AlGaSb quantum cascade lasers emitting at 12 {mu}m. The laser structures are grown on a n-InAs (100) substrate using solid-source molecular beam epitaxy. An InAs/AlGaSb superlattice is used as an active part and an InAs double plasmon waveguide is used for optical confinement. Results show that increased doping concentration in the injection part of the active region expands the current operation range of the devices, allowing laser operation at and above room temperature. The observed threshold current density is 4.0 kA/cm{sup 2} at 300 K; the maximum operation temperature is 340 K.

Ohtani, K.; Moriyasu, Y.; Ohnishi, H.; Ohno, H. [Laboratory for Nanoelectronics and Semiconductor Spintronics, Research Institute of Electrical Communication, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)

2007-06-25T23:59:59.000Z

149

Observation of columnar microstructure in lattice-matched InAlN/GaN grown by plasma assisted molecular beam epitaxy  

SciTech Connect

Nominally lattice matched InAlN/GaN was grown by plasma-assisted molecular beam epitaxy, and the intrinsic microstructure was investigated via x-ray diffraction, transmission electron microscopy, and atom probe tomography. The InAlN showed a cellular structure, which was comprised of {approx}10 nm wide Al-rich cores and {approx}1 nm In-rich InAlN intercellular boundaries. Despite the strong laterally non-uniform In distribution, both vertical and lateral lattices are unperturbed by the cellular structure, as evidenced by strong thickness fringes in on-axis {omega}-2{theta} high resolution x-ray diffraction scans, coherence lengths derived from on-axis (0002) and off-axis (1012) {omega}-2{theta} high resolution x-ray diffraction scans, and a modified Williamson-Hall analysis for on-axis reflections.

Choi, Soojeong; Wu Feng; Shivaraman, Ravi; Young, Erin C.; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

2012-06-04T23:59:59.000Z

150

Characterization of heavy masses of two-dimensional conduction subband in InGaAs/InAlAs MQW structures by pulsed cyclotron resonance technology  

SciTech Connect

Conduction-band effective masses in a direction parallel to the quantum well plane were investigated in n-type-modulation-doped InGaAs/InAlAs multiquantum well system. Thicknesses of well and barrier were 5 and 10 nm. Three highly-doped specimens having about 1 {times} 10{sup 12} cm{sup {minus}2} per one quantum well were prepared by MBE. Double-crystal X-ray diffraction was used to check the crystal quality. Heavy electron effective masses, almost 50% bigger than the band edge mass of 0.041m{sub 0}, were measured by far-infrared and infrared cyclotron resonances under pulse high magnetic fields up to 100 T. Nonparabolicity of this subband was less than 12% by comparing the two cyclotron resonances. Observed two-dimensional subband structure was quite different from conduction-band effective mass in a direction perpendicular to the same quantum well and from GaAs/GaAlAs quantum well system.

Kotera, N.; Tanaka, K. [Kyushu Inst. of Technology, Iizuka, Fukuoka (Japan); Arimoto, H.; Miura, N. [Univ. of Tokyo, Roppongi, Tokyo (Japan). Inst. of Solid State Physics; Jones, E.D. [Sandia National Labs., Albuquerque, NM (United States); Mishima, T. [Hitachi Ltd., Kokubunji, Tokyo (Japan). Central Research Lab.; Washima, M. [Hitachi Cable, Ltd., Tsukuba, Ibaraki (Japan). Advanced Research Center

1998-05-01T23:59:59.000Z

151

Approved for public release; distribution is unlimited. ERDC TN-DOER-C36  

E-Print Network (OSTI)

Material Placement and Dis pos al Operations in R elation to B ird/Wildlife Aircraft S trike Hazards (B that landed in the Hudson River (U.S. Airways Flight 1549) in January 2009 as a result of collision provided by USACE Savannah District). #12;ERDC TN-DOER-C36 July 2011 2 restoration conflicts with nearby

US Army Corps of Engineers

152

First-principles study of compensation mechanisms in negatively charged LaGaO3/MgAl2O4 interfaces  

Thin film oxide heterostructures with a bound charge at the interface require electrical compensation, which can involve redistribution of mobile charge carriers. We explore a model LaGaO3(001)//MgAl2O4(001) heterostructure with nominally negatively charged interfaces using first-principles methods and a Poisson-Boltzmann equation. We find that charge compensation by oxygen vacancies with quadratically decaying concentration away from the interface is more favorable than electronic redistribution. These vacancies have a potential to enhance ionic conductivity along the interfaces.

Rébola, Alejandro; Fong, Dillon D.; Eastman, Jeffrey A.; Ö?üt, Serdar; Zapol, Peter

2013-06-01T23:59:59.000Z

153

LBNL-4183E-rev1 N NA AT TU UR RA AL L G GA AS S V VA AR RI  

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

4183E-rev1 4183E-rev1 N NA AT TU UR RA AL L G GA AS S V VA AR RI IA AB BI IL LI IT TY Y I IN N C CA AL LI IF FO OR RN NI IA A: : E EN NV VI IR RO ON NM ME EN NT TA AL L I IM MP PA AC CT TS S A AN ND D D DE EV VI IC CE E P PE ER RF FO OR RM MA AN NC CE E E EX XP PE ER RI IM ME EN NT TA AL L E EV VA AL LU UA AT TI IO ON N O OF F I IN NS ST TA AL LL LE ED D C CO OO OK KI IN NG G E EX XH HA AU US ST T F FA AN N P PE ER RF FO OR RM MA AN NC CE E Brett C. Singer, William W. Delp and Michael G. Apte Indoor Environment Department Atmospheric Sciences Department Environmental Energy Technologies Division July 2011 (Revised February 2012) Disclaimer 1 This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor any of

154

AL  

E-Print Network (OSTI)

AL. EMERGENCY PREPAREDNESS SYLLABUS ATTACHMENT. EMERGENCY NOTIFICATION PROCEDURES are based on a simple concept - if you hear a.

155

PUBLISHED ONLINE: 17 OCTOBER 2010 | DOI: 10.1038/NMAT2879 Waterproof AlInGaP optoelectronics on  

E-Print Network (OSTI)

InGaP optoelectronics on stretchable substrates with applications in biomedicine and robotics Rak-Hwan Kim1 , Dae opportunities for optoelectronic devices. A ll established forms of inorganic light-emitting diodes (LEDs restricting the ways in which these devices can be used. Research in organic optoelectronic materials

Rogers, John A.

156

Localized electrons in the metallic phase of the two-dimensional electron system at ,,Al,Ga...As-GaAs heterojunctions  

E-Print Network (OSTI)

Localized electrons in the metallic phase of the two-dimensional electron system at ,,Al, United Kingdom Received 29 October 1996 Using the effect of electron focusing we measure the Fermi wave vector of the delocalized electrons in a two-dimensional 2D electron system. After obtaining the total

Ludwig-Maximilians-Universität, München

157

Theoretical investigation of direct and phonon-assisted tunneling currents in InAlGaAs/InGaAs bulk and quantum-well interband tunnel junctions for multijunction solar cells  

Science Journals Connector (OSTI)

Direct and phonon-assisted tunneling currents in InAlGaAs-InGaAs bulk and double-quantum-well interband tunnel heterojunctions are simulated rigorously using the nonequilibrium Green's function formalism for coherent and dissipative quantum transport in combination with a simple two-band tight-binding model for the electronic structure. A realistic band profile and the associated built-in electrostatic field are obtained via self-consistent coupling of the transport formalism to Poisson's equation. The model reproduces experimentally observed features in the current-voltage characteristics of the devices, such as the pronounced current enhancement in the quantum-well junction as compared to the bulk junction and the structure appearing in the negative-differential resistance regime due to quantization of emitter states. Local maps of density of states and the current spectrum reveal the impact of quasibound states, electric fields, and electron-phonon scattering on the interband tunneling current. In this way, resonances appearing in the current through the double-quantum-well structure in the negative-differential resistance regime can be related to the alignment of subbands in the coupled quantum wells.

U. Aeberhard

2013-02-05T23:59:59.000Z

158

Photoelectric and luminescence properties of GaSb-Based nanoheterostructures with a deep Al(As)Sb/InAsSb/Al(As)Sb quantum well grown by metalorganic vapor-phase epitaxy  

SciTech Connect

The luminescence and photoelectric properties of heterostructures with a deep Al(As)Sb/InAsSb/Al(As)Sb quantum well grown on n-GaSb substrates by metalorganic vapor-phase epitaxy are investigated. Intense superlinear luminescence and increased optical power as a function of the pump current in the photon energy range of 0.6-0.8 eV are observed at temperatures of T = 77 and 300 K. The photoelectric, current-voltage, and capacitance characteristics of these heterostructures are studied in detail. The photosensitivity is examined with photodetectors operating in the photovoltaic mode in the spectral range of 0.9-2.0 {mu}m. The sensitivity maximum at room temperature is observed at a wavelength of 1.55 {mu}m. The quantum efficiency, detectivity, and response time of the photodetectors were estimated. The quantum efficiency and detectivity at the peak of the photosensitivity spectrum are as high as {eta} = 0.6-0.7 and D{sub {lambda}max}{sup *} = (5-7) Multiplication-Sign 10{sup 10} cm Hz{sup 1/2} W{sup -1}, respectively. The photodiode response time determined as the rise time of the photoresponse pulse from 0.1 to the level 0.9 is 100-200 ps. The photodiode transmission bandwidth is 2-3 GHz. Photodetectors with a deep Al(As)Sb/InAsSb/Al(As)Sb quantum well grown on n-GaSb substrates are promising foruse in heterodyne detection systems and in information technologies.

Mikhailova, M. P.; Andreev, I. A., E-mail: igor@iropt9.ioffe.ru; Ivanov, E. V.; Konovalov, G. G.; Grebentshikova, E. A.; Yakovlev, Yu. P. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Hulicius, E.; Hospodkova, A.; Pangrac, Y. [Academy of Sciences of the Czech Republic, Institute of Physics (Czech Republic)] [Academy of Sciences of the Czech Republic, Institute of Physics (Czech Republic)

2013-08-15T23:59:59.000Z

159

Thickness Effect of Al-Doped ZnO Window Layer on Damp Heat Stability of CuInGaSe2 Solar Cells: Preprint  

SciTech Connect

We investigated the damp heat (DH) stability of CuInGaSe2 (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 ?m to a modest 0.50 ?m over an underlying 0.10-?m intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 ?m/3 ?m) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85oC and 85% relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.

Pern, F. J.; Mansfield, L.; DeHart, C.; Glick, S. H.; Yan, F.; Noufi, R.

2011-07-01T23:59:59.000Z

160

Thickness Effect of Al-Doped ZnO Window Layer on Damp-Heat Stability of CuInGaSe2 Solar Cells  

SciTech Connect

We investigated the damp heat (DH) stability of CuInGaSe{sub 2} (CIGS) solar cells as a function of thickness of the Al-doped ZnO (AZO) window layer from the 'standard' 0.12 {micro}m to a modest 0.50 {micro}m over an underlying 0.10-{micro}m intrinsic ZnO buffer layer. The CIGS cells were prepared with external electrical contact using fine Au wire to the tiny 'standard' Ni/Al (0.05 {micro}m/3 {micro}m) metal grid contact pads. Bare cell coupons and sample sets encapsulated in a specially designed, Al-frame test structure with an opening for moisture ingress control using a TPT backsheet were exposed to DH at 85 C and 85% relative humidity, and characterized by current-voltage (I-V), quantum efficiency (QE), and (electrochemical) impedance spectroscopy (ECIS). The results show that bare cells exhibited rapid degradation within 50-100 h, accompanied by film wrinkling and delamination and corrosion of Mo and AlNi grid, regardless of AZO thickness. In contrast, the encapsulated cells did not show film wrinkling, delamination, and Mo corrosion after 168 h DH exposure; but the trend of efficiency degradation rate showed a weak correlation to the AZO thickness.

Pern, F. J.; Mansfield, L.; DeHart, C.; Glick, S. H.; Yan, F.; Noufi, R.

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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
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161

AT-TN: Mr. R. L. Rudolph  

Office of Legacy Management (LM)

MAR 1 ? 7982 MAR 1 ? 7982 3echW tiational, Inc. AT-TN: Mr. R. L. Rudolph PO Box 350 Oak Ridge, TFi 37830 Gentlemen: CRITERIA FOR REMEDIAL ACTION AT ACID/PUEBLO AND BAY0 CANYONS; REQUEST FOR COST/BENEFIT ANALYSES OF REMEDIAL ACTION OPTIONS AT THE CANYONS Enclosed are several pieces of cqrespondence related to AcldjPueblo * and Bayo Canyons. . . . . . . . . . . . . . First, EP has concurred with the remedial action DATE criteria for the New Mexico sftes that were proposed to them on August 20, 1987 (wfth the addition of a criterion for Pu-239 added RTG SYMBO, October 20, 7981). In summary, the cri terla will be: . . . . . . . IUITI*LSSIG. f ---- Radionuclfdt Sr-90 cs-137 Th-228 Th-230 Th-232 u-234 U-238 Pu-239 Pu-240 Pu-241 Am-241 Sofl Limft (pCi/g) 100 80

162

SLAC_TN04051_04.dvi  

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

8 8 SLAC-TN-04-051 Sep. 2004 (Jan. 2005) Abstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Electron Conditioning of Technical Aluminum Surfaces ¤ F. Le Pimpec, F. King, and R. E. Kirby

163

Effect of Hydrogen and Nitrogen Carrier Gas Ratio on the Structural and Optical Properties of AlInGaN Alloy  

Science Journals Connector (OSTI)

Undoped AlInGaN epilayers on GaN templates with different hydrogen (H2) and nitrogen (N2) carrier gas ratios (1:8, 2:8, and 3:8 as samples 1, 2 and 3, respectively) were grown. When the flow ratio of H2 and N2 rises from 1:8 to 3:8, an indium composition decrease from 3% to 1.2% is observed while the aluminum content stays constant at any flow ratio. Due to the quantum-dot-like effect, photoluminescence intensity is enhanced in the sample with the low carrier gas flow ratio of H2/N2. However, the potential well caused by indium uneven distribution is nonuniform, which is more severe in the sample with carrier gas flow ratio 1:8. The process of carrier transfer from shallow to deep potential wells would be more difficult to accomplish, resulting in the reduction of the photoluminescence intensity. This is found to be consistent with the carriers' lifetime with the help of time-resolved photoluminescence.

Feng Xiang-Xu (???); Liu Nai-Xin (???); Zhang Lian (??); Zhang Ning (??); Zeng Jian-Ping (???); Wei Xue-Cheng (???); Liu Zhe (??); Wei Tong-Bo (???); Wang Jun-Xi (???); Li Jin-Min (???)

2013-01-01T23:59:59.000Z

164

Broadening and splitting of emission spectra of a GaInAs/AlInAs quantum cascade laser in a quantising magnetic field  

SciTech Connect

We have studied the effect of a relatively weak quantising magnetic field on emission spectra of a GaInAs/AlInAs quantum cascade laser near 10 K. The results demonstrate that, as the magnetic field induction increases to 7 T, the spectra broaden (to 5 meV) and split into three emission bands. As a result, we observe simultaneously up to 80 longitudinal lasing modes in the three bands and the integrated laser output intensity increases 70 times. The presence of bands in the emission spectra can be accounted for in terms of the magnetic quantisation of the laser levels into spinsplit Landau levels. The increase in emission intensity is attributable primarily to phonon resonance adjustment in a magnetic field. (lasers)

Zasavitskii, I I; Pashkeev, D A; Bushuev, E V; Mikaelyan, G T

2013-02-28T23:59:59.000Z

165

A wide-bandwidth low-noise InGaAsP-InAlAs superlattice avalanche photodiode with a flip-chip structure for wavelengths of 1. 3 and 1. 55 [mu]m  

SciTech Connect

This paper reports the fabrication of a flip-chip InGaAsP-InAlAs superlattice avalanche photodiode using gas source molecular beam epitaxy. The incident light reaches the InGaAs photoabsorption layer through the InP substrate and an InGaAsP-InAlAs superlattice multiplication region which are transparent for wavelengths of 1.55 and 1.3 [mu]m. The light reflection by the electrode enables the absorption layer to be as thin as 0.8 [mu]m without significantly reducing the quantum efficiency. A maximum bandwidth of 17 GHz was obtained at a low multiplication factor because of the transit time through the absorption layer is reduced.

Kagawa, Toshiaki; Kawamura, Yuichi; Iwamura, Hidetoshi (NTT Opto-electronics Labs., Atsugi-shi, Kanagawa (Japan))

1993-05-01T23:59:59.000Z

166

Built-in biaxial strain dependence of I'-X transport in GaAs/ln,Al, -,AsJGaAs pseudomorphic heterojunction barriers (x=0, 0.03, and 0.06)  

E-Print Network (OSTI)

of thermionic emission and tunneling currents for the case of IT-X transport are signifi- cantly smaller thanBuilt-in biaxial strain dependence of I'-X transport in GaAs/ln,Al, -,AsJGaAs pseudomorphic 5800, Albuquerque, New Mexico 8718.5-1370 (Received 12 May 1994; accepted for publication 26 August

Yang, Kyounghoon

167

Zigzag and helical AlN layer prepared by glancing angle deposition and its application as a buffer layer in a GaN-based light-emitting diode  

Science Journals Connector (OSTI)

This study investigates an aluminum nitride (AlN) nanorod structure sputtered by glancing angle deposition (GLAD) and its application as a buffer layer for GaN-based light-emitting diodes (LEDs) that are fabricated on sapphire substrates. The ray tracing ...

Lung-Chien Chen; Ching-Ho Tien; Liu Xuguang; Xu Bingshe

2012-01-01T23:59:59.000Z

168

Band alignment of HfO{sub 2}/Al{sub 0.25}Ga{sub 0.75}N determined by x-ray photoelectron spectroscopy: Effect of SiH{sub 4} surface treatment  

SciTech Connect

The band-alignment of atomic layer deposited (ALD)-HfO{sub 2}/Al{sub 0.25}Ga{sub 0.75}N was studied by high resolution x-ray photoelectron spectroscopy measurements for both the non-passivated and SiH{sub 4} passivated AlGaN surfaces. The valence band offset and the conduction band offset for the ALD-HfO{sub 2}/Al{sub 0.25}Ga{sub 0.75}N interface were found to be 0.43?eV and 1.47?eV, respectively, for the non-passivated sample, and 0.59?eV and 1.31?eV, respectively, for the SiH{sub 4}-passivated sample. The difference in the band alignment is dominated by the band bending or band shift in the AlGaN substrate as a result of the different interlayers formed by the two surface preparations.

Samuel Owen, Man Hon, E-mail: m.owen.sg@ieee.org, E-mail: yeo@ieee.org; Amin Bhuiyan, Maruf; Zhou, Qian; Yeo, Yee-Chia, E-mail: m.owen.sg@ieee.org, E-mail: yeo@ieee.org [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 119260 (Singapore); Zhang, Zheng; Sheng Pan, Ji [Institute of Materials Research and Engineering, A-STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602 (Singapore)

2014-03-03T23:59:59.000Z

169

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

170

Construction of an Enterococcus faecalis Tn917-Mediated-Gene-Disruption Library Offers Insight into Tn917 Insertion Patterns  

Science Journals Connector (OSTI)

...We estimate that the library of 540 mutants corresponds...made up of intergenic space, suggesting that there...Tn917-mediated-gene-disruption library offers insight into Tn917...whose sequence is in the public domain, over 10% of...faecalis genetics Gene Library Listeria monocytogenes...

Danielle A. Garsin; Jonathan Urbach; Jose C. Huguet-Tapia; Joseph E. Peters; Frederick M. Ausubel

2004-11-01T23:59:59.000Z

171

Innovational radiation sensor by integrating AL2O3:C optically stimulated luminescent dosemeter and GaN detectors  

Science Journals Connector (OSTI)

......dosimetry (i.e. an active dosemeter) or one...detectable dose and the active performance of the...various applications. MATERIALS AND METHODS alpha-Al2O3...by the ratio of cathode current to optical...could be operated in active mode. | Department...radiation effects Light Materials Testing Photochemistry......

Tai-Chang Chen; Kunakorn Poochinda; Thomas G. Stoebe

2006-09-01T23:59:59.000Z

172

AlGaInP thin-film LED with omni-directionally reflector and ITO transparent conducting n-type contact  

Science Journals Connector (OSTI)

In this paper a novel AlGaInP thin-film light-emitting diode (LED) with omni-directionally reflector (ODR) and transparent conducting indium tin oxide (ITO) n-type contact structure is proposed, and fabrication process is developed. This reflector is realized with the combination of a low-refractive-index dielectric layer and a high reflectivity metal layer. This allows the light emitted or internally reflected downwardly towards the GaAs substrate at any angle of incidence to be reflected towards the top surface of the chip. ITO n-type contact is used for anti-reflection and current spreading layers on the ODR-LED with ITO. The sheet resistance of the ITO films (95 nm) deposited on n-ohmic contact of ODR-LED is of the order 23.5?/ with up to 90% transmittance (above 92% for 590–770 nm) in the visible region of the spectrum. The optical and electrical characteristics of the ODR-LED with ITO are presented and compared to conventional AS-LED and ODR-LED without ITO. It is shown that the light output from the ODR-LED with ITO at forward current 20 mA exceeds that of AS-LED and ODR-LED without ITO by about a factor of 1.63 and 0.16, respectively. A favourable luminous intensity of 218.3 mcd from the ODR-LED with ITO (peak wavelength 620 nm) could be obtained under 20 mA injection, which is 2.63 times and 1.21 times higher than that of AS-LED and ODR-LED without ITO, respectively.

Zhang Jian-Ming; Zou De-Shu; Xu Chen; Guo Wei-Ling; Zhu Yan-Xu; Liang Ting; Da Xiao-Li; Li Jian-Jun; Shen Guang-Di

2007-01-01T23:59:59.000Z

173

Effective passivation of In{sub 0.2}Ga{sub 0.8}As by HfO{sub 2} surpassing Al{sub 2}O{sub 3} via in-situ atomic layer deposition  

SciTech Connect

High {kappa} gate dielectrics of HfO{sub 2} and Al{sub 2}O{sub 3} were deposited on molecular beam epitaxy-grown In{sub 0.2}Ga{sub 0.8}As pristine surface using in-situ atomic-layer-deposition (ALD) without any surface treatment or passivation layer. The ALD-HfO{sub 2}/p-In{sub 0.2}Ga{sub 0.8}As interface showed notable reduction in the interfacial density of states (D{sub it}), deduced from quasi-static capacitance-voltage and conductance-voltage (G-V) at room temperature and 100 Degree-Sign C. More significantly, the midgap peak commonly observed in the D{sub it}(E) of ALD-oxides/In{sub 0.2}Ga{sub 0.8}As is now greatly diminished. The midgap D{sub it} value decreases from {>=}15 Multiplication-Sign 10{sup 12} eV{sup -1} cm{sup -2} for ALD-Al{sub 2}O{sub 3} to {approx}2-4 Multiplication-Sign 10{sup 12} eV{sup -1} cm{sup -2} for ALD-HfO{sub 2}. Further, thermal stability at 850 Degree-Sign C was achieved in the HfO{sub 2}/In{sub 0.2}Ga{sub 0.8}As, whereas C-V characteristics of Al{sub 2}O{sub 3}/p-In{sub 0.2}Ga{sub 0.8}As degraded after the high temperature annealing. From in-situ x-ray photoelectron spectra, the AsO{sub x}, which is not the oxidized state from the native oxide, but is an induced state from adsorption of trimethylaluminum and H{sub 2}O, was found at the ALD-Al{sub 2}O{sub 3}/In{sub 0.2}Ga{sub 0.8}As interface, while that was not detected at the ALD-HfO{sub 2}/In{sub 0.2}Ga{sub 0.8}As interface.

Chang, Y. H.; Chiang, T. H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, C. A.; Liu, Y. T.; Lin, H. Y.; Huang, M. L.; Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, T. D.; Hong, M. [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Pi, T. W. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China)

2012-10-22T23:59:59.000Z

174

P.O. Box 117, Oak Ridge, TN 37831  

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

Box 117, Oak Ridge, TN 37831 g (865) 241-8893 g IVsurveys@orau.org On the Web: www.orau.orgenvironmental-assessments-health-physics Oak Ridge Associated Universities (ORAU) is a...

175

DOE - Office of Legacy Management -- Vitro Corp of America - TN 04  

Office of Legacy Management (LM)

TN 04 TN 04 FUSRAP Considered Sites Site: Vitro Corp. of America (TN.04) Eliminated from further consideration under FUSRAP Designated Name: Not Designated Alternate Name: Heavy Minerals Company Vitro Chemical Company TN.04-4 TN.04-5 Location: 4000 North Hawthorne Street , Chattanooga , Tennessee TN.04-5 Evaluation Year: 1990 TN.04-1 Site Operations: Processed mineral monazite to produce a thorium-uranium hydroxide and a series of rare earth products. TN.04-4 Site Disposition: Eliminated - Site licensed by AEC and State of Tennessee - No Authority to perform remedial action under FUSRAP TN.04-2 TN.04-3 Radioactive Materials Handled: Yes Primary Radioactive Materials Handled: Thorium Metal, ThF4, Thorium Oxide TN.04-1 Radiological Survey(s): None Indicated

176

Strain relief and AlSb buffer layer morphology in GaSb heteroepitaxial films grown on Si as revealed by high-angle annular dark-field scanning transmission electron microscopy  

SciTech Connect

The interfacial misfit (IMF) dislocation array of an epitaxial GaSb film on a Si substrate has been imaged with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The mismatch strain accommodation through dislocation formation has been investigated using geometric phase analysis (GPA) on HAADF-STEM images with atomic resolution to probe the defects' local strain distribution. These measurements indicate that the lattice parameter of the epitaxial film recovers its bulk value within three unit cells from the interface due to the relaxation through IMF dislocations. The atomic number contrast of the HAADF-STEM images and energy dispersive x-ray spectrometry illustrate the formation of islands of AlSb buffer layer along the interface. The role of the AlSb buffer layer in facilitating the GaSb film growth on Si is further elucidated by investigating the strain field of the islands with the GPA.

Vajargah, S. Hosseini; Couillard, M.; Cui, K. [Department of Material Science and Engineering, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4M1 (Canada); Tavakoli, S. Ghanad; Robinson, B.; Kleiman, R. N.; Preston, J. S. [Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Botton, G. A. [Department of Material Science and Engineering, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4M1 (Canada); Canadian Centre for Electron Microscopy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)

2011-02-21T23:59:59.000Z

177

Electrical conduction mechanism in La{sub 3}Ta{sub 0.5}Ga{sub 5.3}Al{sub 0.2}O{sub 14} single crystals  

SciTech Connect

The electrical conduction mechanism in La{sub 3}Ta{sub 0.5}Ga{sub 5.3}Al{sub 0.2}O{sub 14} (LTGA) single crystals was studied by nonstoichiometric defect formation during crystal growth. Since stoichiometric LTGA is not congruent, the single crystal grown from the stoichiometric melt was Ta-poor and Al-rich, where Al atoms were substituted not only in Ga sites but also in Ta sites. The population of the substitutional Al in Ta sites increased with increasing oxygen partial pressure during growth (growth-pO{sub 2}) in the range from 0.01 to 1?atm. Below 600?°C, substitutional Al atoms in Ta sites were ionized to yield holes, and thus the electrical conductivity of the LTGA crystal depended on temperature and the growth-pO{sub 2}. The dependence of the electrical conductivity on the growth-pO{sub 2} decreased as temperature increased. The temperature rise increases ionic conductivity, for which the dominant carriers are oxygen defects formed by the anion Frenkel reaction.

Yaokawa, Ritsuko, E-mail: e4777-1009@yahoo.co.jp; Aota, Katsumi [Citizen Holdings Co., Ltd., 840, Shimotomi, Tokorozawa, Saitama 359-8511 (Japan); Uda, Satoshi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2013-12-14T23:59:59.000Z

178

United States Patent [191 Jalali et al.  

E-Print Network (OSTI)

antennas: SPIE vol. 1703 (1992) 264-271. GA Magel et al.: "Phosphosilicate Glass waveguides for phased

Jalali. Bahram

179

Surface plasmon-enhanced nanoporous GaN-based green light-emitting diodes with Al2O3 passivation layer  

Science Journals Connector (OSTI)

A surface plasmon (SP)-enhanced nanoporous GaN-based green LED based on top-down processing technology has been successfully fabricated. This SP-enhanced LED consists of nanopores...

Yu, Zhi-Guo; Zhao, Li-Xia; Wei, Xue-Cheng; Sun, Xue-Jiao; An, Ping-Bo; Zhu, Shi-Chao; Liu, Lei; Tian, Li-Xin; Zhang, Feng; Lu, Hong-Xi; Wang, Jun-Xi; Zeng, Yi-Ping; Li, Jin-Min

2014-01-01T23:59:59.000Z

180

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

SciTech Connect

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

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

2013-04-07T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Origin of improved scintillation efficiency in (Lu,Gd){sub 3}(Ga,Al){sub 5}O{sub 12}:Ce multicomponent garnets: An X-ray absorption near edge spectroscopy study  

SciTech Connect

In the recent successful improvement of scintillation efficiency in Lu{sub 3}Al{sub 5}O{sub 12}:Ce driven by Ga{sup 3+} and Gd{sup 3+} admixture, the “band-gap engineering” and energy level positioning have been considered the valid strategies so far. This study revealed that this improvement was also associated with the cerium valence instability along with the changes of chemical composition. By utilizing X-ray absorption near edge spectroscopy technique, tuning the Ce{sup 3+}/Ce{sup 4+} ratio by Ga{sup 3+} admixture was evidenced, while it was kept nearly stable with the Gd{sup 3+} admixture. Ce valence instability and Ce{sup 3+}/Ce{sup 4+} ratio in multicomponent garnets can be driven by the energy separation between 4f ground state of Ce{sup 3+} and Fermi level.

Wu, Yuntao, E-mail: caswyt@hotmail.com; Luo, Jialiang; Ren, Guohao [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No.215 Road, Jiading, Shanghai 201899 (China); Nikl, Martin [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 16253 Prague 6 (Czech Republic)

2014-01-01T23:59:59.000Z

182

621.315.592 AlXGa1-XN  

E-Print Network (OSTI)

, : Si = (I2 ./f ) oAA/ , A0 ­ , A ­ , ­ 1, f ­ . 9. AlxGa1-xN AlN/AlGaN CF4/Ar 0x1. , AlxGa1-xN AlN/AlGaN CF4/Ar 0x1. , : 1. AlxGa1-xN 20÷26 0,56,25 . 5. AlxGa1-xN CF4/Ar ( ) / ( ) CF4/Ar = 20/4 sccm, =300, =150 = 10 . 6. AlN/Al0

Titov, Anatoly

183

Infrared emission from the substrate of GaAs-based semiconductor lasers Mathias Ziegler,1,a  

E-Print Network (OSTI)

GaP single QW surrounded by AlGaInP waveguide WG and cladding layers, whereas the NIR laser incorporates a GaInfrared emission from the substrate of GaAs-based semiconductor lasers Mathias Ziegler,1,a Robert in GaAs-based broad-area laser diodes. Spectrally and spatially resolved scanning optical microscopy

Peinke, Joachim

184

ErAs:,,InGaAs...1-x,,InAlAs...x alloy power generator modules Gehong Zeng,a  

E-Print Network (OSTI)

p-type ErAs:InGaAs alloy thermoelectric elements. The thermoelectric properties of the materials power and efficiency of a thermoelectric generator module depend largely on the material. Thermoelectric properties can be improved by introducing nanometer scale structure into materials.2 In this way

Bowers, John

185

Deep analysis of Selective area growth InGaAlAs SAG MQWs structures using micro beam high resolution X-ray diffraction and micro photoluminescence  

E-Print Network (OSTI)

to the traditional InGaAsP/InP for these specific applications is due to its larger conduction-band gap offset-speed 40 Gb/s electro-absorption modulators. The superiority of this material system compared

Sirenko, Andrei

186

Mass-deformed $T_N$ as a linear quiver  

E-Print Network (OSTI)

The $T_N$ theory is a non-Lagrangian theory with SU(N) flavor symmetry. We argue that when mass terms are given so that two of SU(N)'s are both broken to SU(N-1) x U(1), it becomes $T_{N-1}$ theory coupled to an SU(N-1) vector multiplet together with N fundamentals. This implies that when two of SU(N)'s are both broken to U(1)$^{N-1}$, the theory becomes a linear quiver. We perform various checks of this statement, by using the 5d partition function, the structure of the coupling constants, the Higgs branch, and the Seiberg-Witten curve. We also study the case with more general punctures.

Hirotaka Hayashi; Yuji Tachikawa; Kazuya Yonekura

2014-10-25T23:59:59.000Z

187

www.latticesemi.com 20-1 tn1078_04.0 October 2005 Technical Note TN1078  

E-Print Network (OSTI)

the LatticeECPTM and LatticeECTM devices need to be configured at power-up. This configu- ration can be doneECP/EC Family Handbook · Lattice technical note TN1053, LatticeECP/EC sysCONFIGTM Usage Guide · isp · Properly installed ispVM® System 14.3 or later SPI/SPIX Differences The majority of SPI Serial Flash

Greenwood, Garrison W.

188

Observation of strontium segregation in LaAlO{sub 3}/SrTiO{sub 3} and NdGaO{sub 3}/SrTiO{sub 3} oxide heterostructures by X-ray photoemission spectroscopy  

SciTech Connect

LaAlO{sub 3} and NdGaO{sub 3} thin films of different thicknesses have been grown by pulsed laser deposition on TiO{sub 2}-terminated SrTiO{sub 3} single crystals and investigated by soft X-ray photoemission spectroscopy. The surface sensitivity of the measurements has been tuned by varying photon energy h? and emission angle ?. In contrast to the core levels of the other elements, the Sr 3d line shows an unexpected splitting for higher surface sensitivity, signaling the presence of a second strontium component. From our quantitative analysis we conclude that during the growth process Sr atoms diffuse away from the substrate and segregate at the surface of the heterostructure, possibly forming strontium oxide.

Treske, Uwe; Heming, Nadine; Knupfer, Martin; Büchner, Bernd; Koitzsch, Andreas, E-mail: a.koitzsch@ifw-dresden.de [Institute for Solid State Research, IFW-Dresden, P.O. Box 270116, DE-01171 Dresden (Germany); Di Gennaro, Emiliano; Scotti di Uccio, Umberto; Miletto Granozio, Fabio [CNR-SPIN and Dipartimento di Fisica, Complesso Universitario di Monte S. Angelo, Via Cintia, 80126 Naples (Italy); Krause, Stefan [Helmholtz-Zentrum Berlin, BESSY, Albert-Einstein-Str. 15, 12489 Berlin (Germany)

2014-01-01T23:59:59.000Z

189

TOF SIMS induced artificial topographical effects on the Y2(Al,Ga)5O12:Tb3+ thin films deposited on Si substrates by the pulsed laser deposition technique  

Science Journals Connector (OSTI)

Abstract The presence of various types of particles on the surface of the pulsed laser deposited (PLD) thin films as well as the differences in the film structure, played an important role to induce artificial topographical effects on Y3(Al,Ga)5O12:Tb3+ PLD thin films deposited on Si substrates measured by time-of-flight secondary ion mass spectroscopy (TOF-SIMS). The two and three-dimensional (2D and 3D) images have been recorded in the positive ion mode. Analysis of the 3D images shows big agglomerated particles on the surface of the Si substrate that appears to be embedded in the substrate and the substrate appears to be on the same level as the particles. This phenomenon is due to the artificial topographic effects which are attributed to the experimental setup of the TOF-SIMS system.

A. Yousif; R.M. Jafer; J.J. Terblans; O.M. Ntwaeaborwa; M.M. Duvenhage; Vinod Kumar; H.C. Swart

2014-01-01T23:59:59.000Z

190

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

E-Print Network (OSTI)

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

Southern California, University of

191

Synchrotron Radiation Photoemission Spectroscopic Study of Band Offsets and Interface Self-cleaning by Atomic Layer Deposited HfO2 on In0.53Ga0.47As and In0.52Al0.48As  

SciTech Connect

The Synchrotron Radiation Photoemission Spectroscopic (SRPES) study was conducted to (a) investigate the surface chemistry of In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.48}As post chemical and thermal treatments, (b) construct band diagram and (c) investigate the interface property of HfO{sub 2}/In{sub 0.53}Ga{sub 0.47}As and HfO{sub 2}/In{sub 0.52}Al{sub 0.48}As. Dilute HCl and HF etch remove native oxides on In{sub 0.53}Ga{sub 0.47}As and In{sub 0.52}Al{sub 0.47}As, whereas in-situ vacuum annealing removes surface arsenic pile-up. After the atomic layer deposition of HfO{sub 2}, native oxides were considerably reduced compared to that in as-received epi-layers, strongly suggesting the self-clean mechanism. Valence and conduction band offsets are measured to be 3.37 {+-} 0.1eV, 1.80 {+-} 0.3eV for In{sub 0.53}Ga{sub 0.47}As and 3.00 {+-} 0.1eV, 1.47 {+-} 0.3eV for In{sub 0.52}Al{sub 0.47}As, respectively.

Kobayashi, Masaharu; /SLAC, SSRL; Chen, P.T.; Sun, Y.; Goel, N.; Majhi, P.; Garner, M; Tsai, W.; Pianetta, P.; Nishi, Y.; /SLAC, SSRL

2008-10-31T23:59:59.000Z

192

We describe the characteristics and application of a 265nm AlGaN light-emitting diode (LED) operated at 1 MHz repetition rate, 1.2 ns pulse duration, 1.32 W average power, 2.3 mW peak  

E-Print Network (OSTI)

We describe the characteristics and application of a 265nm AlGaN light-emitting diode (LEDnm bandwidth. The LED enables the fluorescence decay of weakly emitting phenylalanine to be measured and resonance energy transfer from phenylalanine to tyrosine and tryptophan, the convenience of the 265nm LED

Strathclyde, University of

193

Ohmic contacts to n-GaSb  

E-Print Network (OSTI)

in the semiconductor is measured during the deposition of the metal contact. In using method 1, the I-V characteristics is plotted. The thermionic emission theory predicts the current-voltage characteristics of Schottky diodes as [13]: J(rhcrmionic) = A" T' exp... of different work functions. This situation is also true for metal contacts to n-GaSb. Polyakov et al. [14] examined the Schottky diodes of Al, Au, In, Pd, Ga, and Sb on Te doped n-GaSb. They used the C-V measurements methods. They reported that barrier...

Yang, Zhengchong

2012-06-07T23:59:59.000Z

194

Behavior of Tn3 Resolvase in Solution and Its Interaction with res Marcelo Nollmann,*y  

E-Print Network (OSTI)

velocity analytical ultracentrifugation, and small-angle neutron scattering. Tn3R was found velocity and small-angle neutron scattering data are consistent with a solution structure of dimeric Tn3R-ray scattering and modeled using rigid-body and ab initio techniques. The structures of these sites do not show

Nollmann, Marcelo

195

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

E-Print Network (OSTI)

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

Hisaka, Takayuki

196

Electric field engineering in GaN high electron mobility transistors  

E-Print Network (OSTI)

In the last few years, AlGaN/GaN high electron mobility transistors (HEMTs) have become the top choice for power amplification at frequencies up to 20 GHz. Great interest currently exists in industry and academia to increase ...

Zhao, Xu, S.M. Massachusetts Institute of Technology

2008-01-01T23:59:59.000Z

197

InAs quantum wire induced composition modulation in an In{sub 0.53}Ga{sub 0.37}Al{sub 0.10}As barrier layer grown on an InP substrate  

SciTech Connect

Composition modulations are observed by transmission electron microscopy in In{sub 0.53}Ga{sub 0.37}Al{sub 0.10}As barrier layers that overgrow both single- and multilayer InAs quantum wire structures grown on an InP substrate. Indium-rich (gallium-deficient) regions were observed in the region of the barrier layer lying directly above individual quantum wires, while indium-deficient (gallium-rich) regions were detected in the barrier above the gaps between adjacent underlying quantum wires. The magnitude of such modulation was typically 7% (atomic percent) for both indium and gallium as estimated from the energy dispersive x-ray analysis. The origin of such composition modulations was determined by modeling the chemical potential distribution for indium and gallium on the growth front of the barrier layer at the initial capping stage of the quantum wires with finite element simulations. It is found that the number and positions of the indium-rich regions are determined by the combined effects of strain and surface energy distributions on the barrier material capping the quantum wires. Moreover the estimated magnitudes of the composition modulation for both indium and gallium from the finite element models are in good agreement with the experimental observations. This method provides a simple way to understand the origin of, and to estimate the magnitude of the quantum wire-induced composition modulation in the barrier layer.

Cui, K. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Robinson, B. J. [Center for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Thompson, D. A. [Center for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Botton, G. A. [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada); Center for Emerging Device Technologies, McMaster University, Hamilton, Ontario L8S 4L7 (Canada)

2010-08-15T23:59:59.000Z

198

Lattice-matched epitaxial GaInAsSb/GaSb thermophotovoltaic devices  

SciTech Connect

The materials development of Ga{sub 1{minus}x}In{sub x}As{sub y}Sb{sub 1{minus}y} alloys for lattice-matched thermophotovoltaic (TPV) devices is reported. Epilayers with cutoff wavelength 2--2.4 {micro}m at room temperature and lattice-matched to GaSb substrates were grown by both low-pressure organometallic vapor phase epitaxy and molecular beam epitaxy. These layers exhibit high optical and structural quality. For demonstrating lattice-matched thermophotovoltaic devices, p- and n-type doping studies were performed. Several TPV device structures were investigated, with variations in the base/emitter thicknesses and the incorporation of a high bandgap GaSb or AlGaAsSb window layer. Significant improvement in the external quantum efficiency is observed for devices with an AlGaAsSb window layer compared to those without one.

Wang, C.A.; Choi, H.K.; Turner, G.W.; Spears, D.L.; Manfra, M.J. [Massachusetts Inst. of Tech., Lexington, MA (United States). Lincoln Lab.; Charache, G.W. [Lockheed Martin, Inc., Schenectady, NY (United States)

1997-05-01T23:59:59.000Z

199

Characterisation of Ga-coated and Ga-brazed aluminium  

SciTech Connect

This work is devoted to the brazing of aluminium using liquid gallium. Gallium was deposited on aluminium samples at {approx} 50 Degree-Sign C using a liquid gallium 'polishing' technique. Brazing was undertaken for 30 min at 500 Degree-Sign C in air. EDS (Energy Dispersive X-ray Spectroscopy) and AES (Auger Electron Spectroscopy) characterisation of Ga-coated samples has shown that the Ga surface layer thickness is of ten (or a few tens of) nanometres. Furthermore, aluminium oxide layer (Al{sub 2}O{sub 3}) was shown to be 'descaled' during Ga deposition, which ensures good conditions for further brazing. Cross-section examination of Ga-coated samples shows that liquid gallium penetrates into the aluminium grain boundaries during deposition. The thickness of the grain boundary gallium film was measured using an original EDS technique and is found to be of a few tens of nanometres. The depth of gallium grain boundary penetration is about 300 {mu}m at the deposition temperature. The fracture stress of the brazed joints was measured from tensile tests and was determined to be 33 MPa. Cross-section examination of brazed joints shows that gallium has fully dissolved into the bulk and that the joint is really autogenous. - Highlights: Black-Right-Pointing-Pointer Aluminium can be brazed using liquid gallium deposited by a 'polishing' technique. Black-Right-Pointing-Pointer The aluminium oxide layer is 'descaled' during liquid Ga 'polishing' deposition. Black-Right-Pointing-Pointer EDS can be used for determination of surface and grain boundary Ga film thickness. Black-Right-Pointing-Pointer The surface and grain boundary Ga film thickness is of a few tens of nm. Black-Right-Pointing-Pointer Surface and grain boundary gallium dissolves in the bulk during brazing.

Ferchaud, E. [Universite de Nantes, Polytech'Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France); Christien, F., E-mail: frederic.christien@univ-nantes.fr [Universite de Nantes, Polytech'Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France); Barnier, V. [Ecole Nationale Superieure des Mines, MPI, CNRS UMR5146, Centre SMS, 158 Cours Fauriel, 42023 Saint Etienne (France); Paillard, P. [Universite de Nantes, Polytech'Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France)

2012-05-15T23:59:59.000Z

200

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

Science Journals Connector (OSTI)

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

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

2011-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Kohlenstoffhaltige ternäre Verbindungen (V-Ge-C, Nb-Ga-C, Ta-Ga-C, Ta-Ge-C, Cr-Ga-C und Cr-Ge-C)  

Science Journals Connector (OSTI)

Die ternären Phasen V2GeC, Cr2GaC und Cr2GeC werden aus den Komponenten hergestellt und als H-Phasen identifiziert. Ferner dürften auch die H-Phasen Ti2GaC, und Ti2GeC existieren. In gleicher Weise hergestellte L...

W. Jeitschko; H. Nowotny; F. Benesovsky

1963-01-01T23:59:59.000Z

202

Low interfacial trap density and sub-nm equivalent oxide thickness in In{sub 0.53}Ga{sub 0.47}As (001) metal-oxide-semiconductor devices using molecular beam deposited HfO{sub 2}/Al{sub 2}O{sub 3} as gate dielectrics  

SciTech Connect

We investigated the passivation of In{sub 0.53}Ga{sub 0.47}As (001) surface by molecular beam epitaxy techniques. After growth of strained In{sub 0.53}Ga{sub 0.47}As on InP (001) substrate, HfO{sub 2}/Al{sub 2}O{sub 3} high-{kappa} oxide stacks have been deposited in-situ after surface reconstruction engineering. Excellent capacitance-voltage characteristics have been demonstrated along with low gate leakage currents. The interfacial density of states (D{sub it}) of the Al{sub 2}O{sub 3}/In{sub 0.53}Ga{sub 0.47}As interface have been revealed by conductance measurement, indicating a downward D{sub it} profile from the energy close to the valence band (medium 10{sup 12} cm{sup -2}eV{sup -1}) towards that close to the conduction band (10{sup 11} cm{sup -2}eV{sup -1}). The low D{sub it}'s are in good agreement with the high Fermi-level movement efficiency of greater than 80%. Moreover, excellent scalability of the HfO{sub 2} has been demonstrated as evidenced by the good dependence of capacitance oxide thickness on the HfO{sub 2} thickness (dielectric constant of HfO{sub 2}{approx}20) and the remained low D{sub it}'s due to the thin Al{sub 2}O{sub 3} passivation layer. The sample with HfO{sub 2} (3.4 nm)/Al{sub 2}O{sub 3} (1.2 nm) as the gate dielectrics has exhibited an equivalent oxide thickness of {approx}0.93 nm.

Chu, L. K. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Merckling, C.; Dekoster, J.; Caymax, M. [Interuniversity Microelectronics Center (IMEC vzw), 3001 Leuven (Belgium); Alian, A.; Heyns, M. [Katholieke Universiteit Leuven, 3001 Leuven (Belgium); Interuniversity Microelectronics Center (IMEC vzw), 3001 Leuven (Belgium); Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Hong, M. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2011-07-25T23:59:59.000Z

203

Al composition dependency of interface phonon in the wurtzite quantum cascade laser  

Science Journals Connector (OSTI)

The interface (IF) phonons of the wurtzite quantum cascade lasers (QCL) are investigated using the transfer-...0.2Ga0.8N/GaN and Al0.15Ga0.85N/GaN QCLs, and two IF modes can be changed into other modes if their w...

Gui-chu Chen ???; Guang-han Fan ???

2010-05-01T23:59:59.000Z

204

IEEE PHOTONICS TECHNOLOGY LETTERS 1 High-Power 2.3-m GaSb-Based Linear Laser Array  

E-Print Network (OSTI)

2.3-m laser. Al Ga As Sb cladding layers. Details of the lasers' heterostructure design can be foundIEEE PHOTONICS TECHNOLOGY LETTERS 1 High-Power 2.3-m GaSb-Based Linear Laser Array L. Shterengas, G--High-power 2.3- m In(Al)GaAsSb­GaSb type-I double quantum-well diode laser arrays were fabricated

205

DOE - Office of Legacy Management -- W R Grace - Erwin - TN 05  

Office of Legacy Management (LM)

- Erwin - TN 05 - Erwin - TN 05 FUSRAP Considered Sites Site: W R Grace - Erwin (TN.05) Designated Name: Alternate Name: Location: Evaluation Year: Site Operations: Site Disposition: Radioactive Materials Handled: Primary Radioactive Materials Handled: Radiological Survey(s): Site Status: This site is one of a group of 5 FUSRAP considered sites for which records are available that provide a reasonably complete historical account of their operations and relationship, if any, with MED/AEC operations. However, additional analyses of these historical records, and more recent documentation of decisions concerning the authority and other considerations related to the elimination of these sites from further consideration under FUSRAP is warranted. These analyses will provide the

206

DOE - Office of Legacy Management -- Union Carbide and Carbon Co - TN 10  

Office of Legacy Management (LM)

Carbide and Carbon Co - TN 10 Carbide and Carbon Co - TN 10 FUSRAP Considered Sites Site: Union Carbide and Carbon Co (TN.10) Designated Name: Alternate Name: Location: Evaluation Year: Site Operations: Site Disposition: Radioactive Materials Handled: Primary Radioactive Materials Handled: Radiological Survey(s): Site Status: This site is one of a group of 5 FUSRAP considered sites for which records are available that provide a reasonably complete historical account of their operations and relationship, if any, with MED/AEC operations. However, additional analyses of these historical records, and more recent documentation of decisions concerning the authority and other considerations related to the elimination of these sites from further consideration under FUSRAP is warranted. These analyses will provide the

207

Summary - Mitigation and Remediation of Mercury Contamination at the Y-12 Plant, Oak Ridge, TN  

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

Oak Ridge, TN Oak Ridge, TN EM Project: Mitigation/Remediation of Hg ETR Report Date: April 2008 ETR-13 United States Department of Energy Office of Environmental Management (DOE-EM) External Technical Review of the Mitigation and Remediation of Mercury Contamination at the Y-12 Plant, Oak Ridge, TN Why DOE-EM Did This Review From 1953 to 1983, ~240,000 pounds of mercury (Hg) were released to the East Fork Popular Creek during the operation of the Y-12 Plant. In 1963, direct systematic releases of mercury stopped; however, mercury continues to be released into the creek from various sources of contamination in the Y-12 complex. Remediation completed up to 1992 resulted in an overall reduction of Hg loading from 150 g/day in 1983 to 15 g/day in 1992, with a

208

Summary - Environmental Management Waste Management Facility (EMWMF) at Oak Ridge, TN  

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

Oak Ridge, TN Oak Ridge, TN EM Project: EM Waste Management Facility ETR Report Date: February 2008 ETR-11 United States Department of Energy Office of Environmental Management (DOE-EM) External Technical Review of Environmental Management Waste Management Facility (EMWMF) at Oak Ridge, TN Why DOE-EM Did This Review The Environmental Management Waste Management Facility (EMWMF) is a land disposal facility for wastes generated by environmental restoration activities being conducted at the US Department of Energy's (DOE) Oak Ridge Reservation. Low-level radioactive wastes, hazardous wastes (Subtitle C of the Resource Conservation and Recovery Act), and wastes defined by the Toxic Substances Control Act are approved for disposal in the EMWMF. All of the cells are lined with a

209

Growth and characterization of M-plane GaN and (In,Ga)N/GaN multiple quantum wells.  

E-Print Network (OSTI)

??Thema dieser Arbeit ist die Synthese von Wurtzit M-plane (In,Ga)N(1-100)-Heterostrukturen auf g-LiAlO2(100) mittels plasmaunterstützter Molekularstrahlepitaxie (MBE). Der Einfluß der Wachstumsbedingungen auf die strukturellen, morphologischen, und… (more)

Sun, Yue-Jun

2004-01-01T23:59:59.000Z

210

ERDC/TN APCRP-EA-24 Comparison of Three Biomass Sampling  

E-Print Network (OSTI)

ERDC/TN APCRP-EA-24 July 2010 Comparison of Three Biomass Sampling Techniques on Submersed Aquatic R. Spickard2 PURPOSE: Quantifying biomass to measure aquatic plant abundance can be costly and labor intensive. This technical note compares several alternate, less exhaustive techniques for biomass sampling

US Army Corps of Engineers

211

EA-1514: Proposed Conveyance of Parcel ED-6 to the City of Oak Ridge, TN  

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

This Environmental Assessment was prepared for the conveyance of approximately 336 acres of excess property (i.e., property not needed to fulfill DOE current or foreseeable future requirements) known as Parcel ED-6 to the city of Oak Ridge, TN.

212

Approved for public release; distribution is unlimited. ERDC/TN APCRP-CC-16  

E-Print Network (OSTI)

Approved for public release; distribution is unlimited. ERDC/TN APCRP-CC-16 May 2011 Utilizing evaluated for aquatic use, a small-scale screening method was evaluated at the U.S. Army Engineer Research of America (WSSA) 2007). Topramezone was first registered for use in corn in 2006 and provides post- emergent

US Army Corps of Engineers

213

ION GPS '99, 14-17 September 1999, Nashville, TN Virtual Differential GPS & Road  

E-Print Network (OSTI)

ION GPS '99, 14-17 September 1999, Nashville, TN Virtual Differential GPS & Road Reduction Filtering by Map Matching George Taylor, Quality Engineering and Survey Technology Ltd. (Quest), Newcastle, University of Nevada, Reno. BIOGRAPHIES Dr George Taylor, is a director of Quest Ltd, a software engineering

Tingley, Joseph V.

214

International Conference on Ion Sources (ICIS'09) September 20-25, 2009, Gatlinburg, TN, USA  

E-Print Network (OSTI)

13th International Conference on Ion Sources (ICIS'09) September 20-25, 2009, Gatlinburg, TN, USA Directorate, ORNL New Frontiers in Neutron Sciences Ian Anderson, ORNL, USA Summary of Current and Future Developments Highlighted at the ECRIS08 R. C. Vondrasek, ANL, USA Introduction of the Conference Sponsors R

Pennycook, Steve

215

Wetlands Regulatory Assistance Program ERDC TN-WRAP-12-1 August 2012  

E-Print Network (OSTI)

Wetlands Regulatory Assistance Program ERDC TN-WRAP-12-1 August 2012 Approved for public release; distribution is unlimited. Updating Regional Supplements to the Corps of Engineers Wetland Delineation Manual by Jacob F. Berkowitz PURPOSE: Regional supplements to the Corps of Engineers Wetland Delineation Manual

US Army Corps of Engineers

216

E-Print Network 3.0 - al sio2 si Sample Search Results  

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

Energy ; Materials Science 8 Suppression of quantum well intermixing in GaAsAlGaAs laser structures using phosphorus-doped SiO2 encapsulant layer Summary: investigation....

217

Fusion Power Associates Annual Meeting and Symposium, Oak Ridge, TN, 4-5 December 2007 Gary Johnson  

E-Print Network (OSTI)

1 Fusion Power Associates Annual Meeting and Symposium, Oak Ridge, TN, 4-5 December 2007 Gary Era Status of ITERStatus of ITER #12;2 Fusion Power Associates Annual Meeting and Symposium, Oak Ridge · Technical Status · Summary #12;3 Fusion Power Associates Annual Meeting and Symposium, Oak Ridge, TN, 4

218

Carrier capture dynamics of single InGaAs/GaAs quantum-dot layers  

SciTech Connect

Using 800 nm, 25-fs pulses from a mode locked Ti:Al{sub 2}O{sub 3} laser, we have measured the ultrafast optical reflectivity of MBE-grown, single-layer In{sub 0.4}Ga{sub 0.6}As/GaAs quantum-dot (QD) samples. The QDs are formed via two-stage Stranski-Krastanov growth: following initial InGaAs deposition at a relatively low temperature, self assembly of the QDs occurs during a subsequent higher temperature anneal. The capture times for free carriers excited in the surrounding GaAs (barrier layer) are as short as 140 fs, indicating capture efficiencies for the InGaAs quantum layer approaching 1. The capture rates are positively correlated with initial InGaAs thickness and annealing temperature. With increasing excited carrier density, the capture rate decreases; this slowing of the dynamics is attributed to Pauli state blocking within the InGaAs quantum layer.

Chauhan, K. N.; Riffe, D. M.; Everett, E. A.; Kim, D. J.; Yang, H. [Physics Department, Utah State University, Logan, Utah 84322-4415 (United States)] [Physics Department, Utah State University, Logan, Utah 84322-4415 (United States); Shen, F. K. [Center for Surface Analysis and Applications, Utah State University, Logan, Utah 84322-4415 (United States)] [Center for Surface Analysis and Applications, Utah State University, Logan, Utah 84322-4415 (United States)

2013-05-28T23:59:59.000Z

219

File:USDA-CE-Production-GIFmaps-TN.pdf | Open Energy Information  

Open Energy Info (EERE)

TN.pdf TN.pdf Jump to: navigation, search File File history File usage Tennessee Ethanol Plant Locations Size of this preview: 776 × 600 pixels. Full resolution ‎(1,650 × 1,275 pixels, file size: 332 KB, MIME type: application/pdf) Description Tennessee Ethanol Plant Locations Sources United States Department of Agriculture Related Technologies Biomass, Biofuels, Ethanol Creation Date 2010-01-19 Extent State Countries United States UN Region Northern America States Tennessee External links http://www.nass.usda.gov/Charts_and_Maps/Ethanol_Plants/ File history Click on a date/time to view the file as it appeared at that time. Date/Time Thumbnail Dimensions User Comment current 16:21, 27 December 2010 Thumbnail for version as of 16:21, 27 December 2010 1,650 × 1,275 (332 KB) MapBot (Talk | contribs) Automated bot upload

220

File:EIA-Appalach7-TN-KY-LIQ.pdf | Open Energy Information  

Open Energy Info (EERE)

Appalach7-TN-KY-LIQ.pdf Appalach7-TN-KY-LIQ.pdf Jump to: navigation, search File File history File usage Appalachian Basin, Kentucky and Tennessee By 2001 Liquids Reserve Class Size of this preview: 463 × 599 pixels. Other resolution: 464 × 600 pixels. Full resolution ‎(5,100 × 6,600 pixels, file size: 19.31 MB, MIME type: application/pdf) Description Appalachian Basin, Kentucky and Tennessee By 2001 Liquids Reserve Class Sources Energy Information Administration Authors Samuel H. Limerick; Lucy Luo; Gary Long; David F. Morehouse; Jack Perrin; Robert F. King Related Technologies Oil, Natural Gas Creation Date 2005-09-01 Extent Regional Countries United States UN Region Northern America States Kentucky, Tennessee File history Click on a date/time to view the file as it appeared at that time.

Note: This page contains sample records for the topic "tn al ga" 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

arineSystems 1 Department of Ecologv and Ecolutiorzary Biology University of Tennessee K~~oxrille, TN 37996, USA  

E-Print Network (OSTI)

~~oxrille, TN 37996, USA Accepted30 May 1996 Abstract Particulate organic carbon (POC) and nitrogen (PON

Daly, Kendra L.

222

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

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

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

223

The development of integrated chemical microsensors in GaAs  

SciTech Connect

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

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

1999-11-01T23:59:59.000Z

224

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

Science Journals Connector (OSTI)

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

D. J. Chadi

1984-05-21T23:59:59.000Z

225

Resonant Raman scattering in an InAs/GaAs monolayer structure  

E-Print Network (OSTI)

), embedded in bulklike GaAs with two Al- GaAs cladding layers forming a waveguide. The InAs- mono- layer system used. Raman spectra were excited with a Ti-Sapphire laser, tuned from 1.41 eV to 1.435 e

Nabben, Reinhard

226

Excited state absorption of V/sup 2 +/ and Cr/sup 3 +/ ions in crystal hosts. [V/sup 2 +/ in KMgF/sub 3/; Cr/sup 3 +/ in Na/sub 3/Ga/sub 2/Li/sub 3/F/sub 12/ and BeAl/sub 2/O/sub 4/  

SciTech Connect

We have measured the excited state absorption spectra of KMgF/sub 3/:V/sup 2 +/, Na/sub 3/Ga/sub 2/Li/sub 3/F/sub 12/:Cr/sup 3 +/, and BeAl/sub 2/O/sub 4/:Cr/sup 3 +/. The /sup 4/T/sub 2/ ..-->.. /sup 4/T/sub 1/a, /sup 4/T/sub 1/b transitions were observed for the first two systems, while the /sup 2/E, /sup 2/T/sub 1/ ..-->.. /sup 2/T/sub 2/ transitions were seen for BeAl/sub 2/O/sub 4/:Cr/sup 3 +/. All excited state absorptions, except the /sup 4/T/sub 2/ ..-->.. /sup 4/T/sub 1/a transition, can be understood on the basis of simple crystal field theory. The /sup 4/T/sub 2/ ..-->.. /sup 4/T/sub 1/a transition is found to be profoundly modified by the Jahn-Teller effect, such that it is broader and at higher energy than otherwise expected. This excited state absorption is observed to overlap the emission spectrum of KMgF/sub 3/:V/sup 2 +/, and thereby substantially reduce the effective stimulated emission cross-section.

Payne, S.A.; Chase, L.L.

1987-01-01T23:59:59.000Z

227

Comments on the possible observation of d-d fusion in sonoluminescence (Reference-31 in Taleyarkhan et al. [2002]1  

E-Print Network (OSTI)

et al. [2002]1 ) D. Shapira, M. J. Saltmarsh Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 20 February 2002 Abstract We have repeated the experiment of Taleyarkhan et al.1 in an attempt of the complex time-varying singles rates. Introduction In a recent paper Taleyarkhan et al.1 reported

Lahey, Richard T.

228

Linear Collider Collaboration Tech Notes LCC-0140 SLAC-TN-04-041  

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

0 0 SLAC-TN-04-041 June 2004 Abstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Sensitivity to Nano-Tesla Scale Stray Magnetic Fields J. Frisch, T.O. Raubenheimer, P. Tenenbaum

229

Linear Collider Collaboration Tech Notes LCC-0139 SLAC-TN-04-042  

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

9 9 SLAC-TN-04-042 May 2004 Abstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Alternative Main Linac BNS Configurations for Reduced Energy Spread Andrei Seryi and Peter Tenenbaum

230

Exact partition functions of Higgsed 5d $T_N$ theories  

E-Print Network (OSTI)

We present a general prescription by which we can systematically compute exact partition functions of five-dimensional supersymmetric theories which arise in Higgs branches of the $T_N$ theory. The theories may be realized by webs of 5-branes whose dual geometries are non-toric. We have checked our method by calculating the partition functions of the theories realized in various Higgs branches of the $T_3$ theory. A particularly interesting example is the $E_8$ theory which can be obtained by Higgsing the $T_6$ theory. We explicitly compute the partition function of the $E_8$ theory and find the agreement with the field theory result as well as the enhancement of the global symmetry to $E_8$.

Hirotaka Hayashi; Gianluca Zoccarato

2015-01-19T23:59:59.000Z

231

Linear Collider Collaboration Tech Notes LCC-0141 SLAC-TN-04-040  

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

1 1 SLAC-TN-04-040 May 2004 Abstract This note documents a set of expressions used to explore the issue of whether or not it is reasonable to consider a conventional positron source for a Tesla formatted beam. The critical issue is that of energy deposition in the conversion target and the comparison of the induced stress with the ultimate tensile strength of the target material. Since the length of the incident beam pulse is large in comparison to the ratio of beam size to the speed of sound, the concurrent pressure pulse dissipates in a time short compared to the overall pulse duration and one is left with only the Availability and Failure Effects of NLC Main Linac Mechanical Movers T. M. Himel, C. Spencer, Peter Tenenbaum

232

Darlington AL O'Reillys AL  

E-Print Network (OSTI)

CanungraCk Darlington AL Darlington Coom era R O'Reillys AL Beechmont AL Binna Burra AL BackCk Tyungun AL Numinbah Valley AL NerangR Natural Bridge Numinbah AL Little Nerang Dam AL Albert R Bromfleet AL Benobble AL Wolffdene AL Luscombe AL Wongawallan AL Mt Tamborine Canungra Pimpama R Laheys Lookout

Greenslade, Diana

233

Ralisation et caractrisation d'un transistor effet de champ JFET au GaAs en vue de son intgration avec une photodiode  

E-Print Network (OSTI)

intégration avec une photodiode M. T. Belaroussi, F. Therez et R. Alcubilla (*) Laboratoire d'Automatique et d étendus à la fabrication du circuit intégré GaAlAs-GaAs associant une photodiode à un TEC. Abstract. 2014AlAs-GaAs monolithic integration of a photodiode and FET. Revue Phys. Appl. 22 (1987) 77-82 JANVIER 1987

Paris-Sud XI, Université de

234

Nonlinear absorption edge properties of 1.3-m GaInNAs saturable R. Grange,a  

E-Print Network (OSTI)

-starting and stable operation of the laser at tens of GHz repetition rates.4 So far, InGaAsP,5 InGaAs,6,7 and AlNonlinear absorption edge properties of 1.3- m GaInNAs saturable absorbers R. Grange,a A. Rutz, V above the PL peak and R scales with the linear absorption even in the bandtail. The product R

Keller, Ursula

235

Composition and Interface Analysis of InGaN/GaN Multiquantum...  

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

Analysis of InGaNGaN Multiquantum-Wells on GaN Substrates Using Atom Probe Tomography. Composition and Interface Analysis of InGaNGaN Multiquantum-Wells on GaN...

236

Category:Savannah, GA | Open Energy Information  

Open Energy Info (EERE)

Savannah, GA Savannah, GA Jump to: navigation, search Go Back to PV Economics By Location Media in category "Savannah, GA" The following 16 files are in this category, out of 16 total. SVFullServiceRestaurant Savannah GA Georgia Power Co.png SVFullServiceRestauran... 80 KB SVHospital Savannah GA Georgia Power Co.png SVHospital Savannah GA... 80 KB SVLargeHotel Savannah GA Georgia Power Co.png SVLargeHotel Savannah ... 75 KB SVLargeOffice Savannah GA Georgia Power Co.png SVLargeOffice Savannah... 82 KB SVMediumOffice Savannah GA Georgia Power Co.png SVMediumOffice Savanna... 85 KB SVMidriseApartment Savannah GA Georgia Power Co.png SVMidriseApartment Sav... 80 KB SVOutPatient Savannah GA Georgia Power Co.png SVOutPatient Savannah ... 84 KB SVPrimarySchool Savannah GA Georgia Power Co.png

237

Category:Atlanta, GA | Open Energy Information  

Open Energy Info (EERE)

GA GA Jump to: navigation, search Go Back to PV Economics By Location Media in category "Atlanta, GA" The following 16 files are in this category, out of 16 total. SVFullServiceRestaurant Atlanta GA Georgia Power Co.png SVFullServiceRestauran... 81 KB SVHospital Atlanta GA Georgia Power Co.png SVHospital Atlanta GA ... 81 KB SVLargeHotel Atlanta GA Georgia Power Co.png SVLargeHotel Atlanta G... 74 KB SVLargeOffice Atlanta GA Georgia Power Co.png SVLargeOffice Atlanta ... 82 KB SVMediumOffice Atlanta GA Georgia Power Co.png SVMediumOffice Atlanta... 84 KB SVMidriseApartment Atlanta GA Georgia Power Co.png SVMidriseApartment Atl... 82 KB SVOutPatient Atlanta GA Georgia Power Co.png SVOutPatient Atlanta G... 83 KB SVPrimarySchool Atlanta GA Georgia Power Co.png SVPrimarySchool Atlant...

238

GA SNC Solar | Open Energy Information  

Open Energy Info (EERE)

GA SNC Solar Jump to: navigation, search Name: GA-SNC Solar Place: Nevada Sector: Solar Product: Nevada-based PV project developer and joint venture of GA-Solar North America and...

239

ALS@20  

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

feed-image feed-image Digg: ALSBerkeleyLab Facebook Page: 208064938929 Flickr: advancedlightsource Twitter: ALSBerkeleyLab YouTube: AdvancedLightSource Home About the ALS ALS@20 ALS@20 ALS@20 Kick-Off Celebration Print On Friday, January 11, the Advanced Light Source celebrated the beginning of its 20th anniversary year with a brunch attended by more than 150 current and past staff members. After introductory remarks describing the trials and tribulations encountered during the construction of the ALS from former Director Jay Marx, current ALS Scientific Director Steve Kevan and Director Roger Falcone talked about the progress of the facility over the years. Attendees were then able to view more than 500 historical photos of the ALS and its staff displayed around the room.

240

MOCVD und Charakterisierung von GaN-Dünnschichten und -Nanostrukturen unter Verwendung eines Single-Molecule-Precursors.  

E-Print Network (OSTI)

??In dieser Arbeit wurde detailliert das Potential eines azidischen Single-Molecule-Precursors als mögliche Alternative zum kommerziellen Standardprozess zur Herstellung dünner GaN-Halbleiterdünnschichten evaluiert. Neben den mit maximalen… (more)

Wohlfart, Andreas

2002-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Observation of the potential distribution in GaN-based devices by a scanning electron microscope  

Science Journals Connector (OSTI)

......potential. On the other hand, higher accelerating voltages resulted in blurred images. The second sample was a light emitting diode structure based on AlN where a multiple quantum well (MQW) structure was sandwiched by p- and n-AlGaN materials......

Takahiro Karumi; Shigeyasu Tanaka; Takayoshi Tanji

2014-11-01T23:59:59.000Z

242

Infrared spectroscopy of amorphous hydrogenated GaAs: Evidence for H bridges  

Science Journals Connector (OSTI)

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

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

1982-09-15T23:59:59.000Z

243

ION GPS '99, 14-17 September 1999, Nashville, TN Testing a GPS-based System for the Support of  

E-Print Network (OSTI)

/s, heading ±0.05° and yaw rate ±0.02°/s. GPS (Global Positioning System) is now fully operationalION GPS '99, 14-17 September 1999, Nashville, TN Testing a GPS-based System for the Support of Ship B.Sc. and M.Sc. in Navigation System Engineering from Tokyo University of Mercantile Marine. She

Santerre, Rock

244

Submicron three-dimensional infrared GaAsAlxOy-based photonic crystal using single-step epitaxial growth  

E-Print Network (OSTI)

to determine the transmission characteris- tics. The starting point in the fabrication of the photonic crys-beam patterned resist and sub- sequently the checkerboard pattern is transferred to the metal layer by a lift growth system. After oxide desorption, four periods of alternating 0.2 m Al0.98Ga0.02As/0.2 m Al0.30Ga0

Zhou, Weidong

245

Industry @ ALS  

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

Industry @ ALS Industry @ ALS Industry @ ALS Concrete Industry Benefits from Ancient Romans and the ALS Print Thursday, 17 October 2013 14:24 New insights into the Romans' ingenious concrete harbor structures emerging from ALS beamline research could move the modern concrete industry toward its goal of a reduced carbon footprint. Summary Slide Read more... Moving Industry Forward: Finding the Environmental Opportunity in Biochar Print Thursday, 12 September 2013 08:41 Using ALS Beamlines 10.3.2 and 8.3.2, the Environmental Protection Agency (EPA) is currently investigating how biochar sorbs environmental toxins and which kinds of biochar are the most effective. The possibilities for widespread use have already launched entrepreneurial commercial ventures. Summary Slide

246

Epitaxial growth of aligned AlGalnN nanowires by metal-organic chemical vapor deposition  

DOE Patents (OSTI)

Highly ordered and aligned epitaxy of III-Nitride nanowires is demonstrated in this work. <1010> M-axis is identified as a preferential nanowire growth direction through a detailed study of GaN/AlN trunk/branch nanostructures by transmission electron microscopy. Crystallographic selectivity can be used to achieve spatial and orientational control of nanowire growth. Vertically aligned (Al)GaN nanowires are prepared on M-plane AlN substrates. Horizontally ordered nanowires, extending from the M-plane sidewalls of GaN hexagonal mesas or islands demonstrate new opportunities for self-aligned nanowire devices, interconnects, and networks.

Han, Jung (Woodbridge, CT); Su, Jie (New Haven, CT)

2008-08-05T23:59:59.000Z

247

ALS Visitors  

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

including Ethan Crumlin (at right) about current research in energy storage and battery efficiency. Berkeleyside Editor Lance Knoble toured the ALS and Berkeley Lab with...

248

Beta decay of Ga-62  

E-Print Network (OSTI)

We report a study of the beta decay of Ga-62, whose dominant branch is a superallowed 0(+)-->0(+) transition to the ground state of Zn-62. We find the total half-life to be 115.84+/-0.25 ms. This is the first time that the Ga-62 half-life has been...

Hyman, BC; Iacob, VE; Azhari, A.; Gagliardi, Carl A.; Hardy, John C.; Mayes, VE; Neilson, RG; Sanchez-Vega, M.; Tang, X.; Trache, L.; Tribble, Robert E.

2003-01-01T23:59:59.000Z

249

Combustion of Nano-Aluminum and Liquid Water G.A. Risha, S.F. Son  

E-Print Network (OSTI)

1 Combustion of Nano-Aluminum and Liquid Water G.A. Risha, S.F. Son , R.A. Yetter, V. Yang, and B: Supplemental materials submitted #12;2 Combustion of Nano-Aluminum and Liquid Water G.A. Risha, S.F. Son, R of nano-aluminum (nAl) and liquid water has been conducted. In particular, linear and mass-burning rates

Yang, Vigor

250

Integration of inverted InGaAs MSM array on Si substrate through low temperature  

E-Print Network (OSTI)

to reduce thermal stress at the interface. Huang et al. [2] presented a thin-film InGaAs MSM PD bonded to Si layers including those on InGaAs MSMs and Si/SiO2 is 860 nm. eching window InP epi-layer SiO2 Si Ti Au Au HCl:H3PO4 (1:1) to open a photodetection window. Citric acid was used to remove the InGaAs etching

Huang, Zhaoran "Rena"

251

Suppression of bulk conductivity in InAs/GaSb broken gap composite quantum wells  

SciTech Connect

The two-dimensional topological insulator state in InAs/GaSb quantum wells manifests itself by topologically protected helical edge channel transport relying on an insulating bulk. This work investigates a way of suppressing bulk conductivity by using gallium source materials of different degrees of impurity concentrations. While highest-purity gallium is accompanied by clear conduction through the sample bulk, intentional impurity incorporation leads to a bulk resistance over 1 M?, independent of applied magnetic fields. In addition, ultra high electron mobilities for GaAs/AlGaAs structures fabricated in a molecular beam epitaxy system used for the growth of Sb-based samples are reported.

Charpentier, Christophe; Fält, Stefan; Reichl, Christian; Nichele, Fabrizio; Nath Pal, Atindra; Pietsch, Patrick; Ihn, Thomas; Ensslin, Klaus; Wegscheider, Werner [Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich (Switzerland)] [Laboratory for Solid State Physics, ETH Zürich, 8093 Zürich (Switzerland)

2013-09-09T23:59:59.000Z

252

Optical losses of Al-free lasers for {lambda}=0.808 and 0.98 {mu}m  

SciTech Connect

In this work, we study the origin of the optical losses in Al-free InGaAsP/GaAs ({lambda}=0.808 {mu}m) and InGaAs/GaAs/InGaP ({lambda}=0.980 {mu}m) lasers. Theoretical modeling and the experimental results indicate that the scattering of the laser beam by refractive index fluctuation in the alloys is the dominant loss in our lasers, and the loss due to the free-carrier absorption and scattering by interface roughness are negligible. {copyright} {ital 1996 American Institute of Physics.}

Yi, H.; Diaz, J.; Lane, B.; Razeghi, M. [Center for Quantum Devices, Northwestern University, Evanston, Illinois 60208 (United States)] [Center for Quantum Devices, Northwestern University, Evanston, Illinois 60208 (United States)

1996-11-01T23:59:59.000Z

253

ALS Visitors  

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

ALS Visitors ALS Visitors ALS Visitors Print Wednesday, 29 July 2009 00:00 ALS staff members host a variety of scientific, educational, government, and community-related tours each month. November 2013 poneman U.S. Deputy Secretary of Energy Daniel Poneman visited Berkeley Lab on Friday, Nov. 15, during a brief stay in the Bay Area. Glenn Mara of the University of California Office of the President and Aundra Richards of the DOE Berkeley Site Office joined Deputy Laboratory Director Horst Simon's welcome. They updated Poneman on the lab's future initiatives and current capital projects and heard briefings on cyber security, computing, and the Joint BioEnergy Institute. As second-in-command at DOE, Poneman is responsible for assisting the Secretary of Energy in the management and operations of the agency and acting on his behalf when necessary.During his tour of the ALS, Poneman (right) spoke with Ken Goldberg (Materials Sciences Division) at the CXRO beamline.

254

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

SciTech Connect

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

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

2003-06-16T23:59:59.000Z

255

Sandia National Laboratories: AlGaAs LEDs  

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

electroluminescence was first reported by H.J. Round in 1907, and the first light-emitting diode (LED) was reported by O.V. Losev in 1927. Not until the birth of semiconductor...

256

Doping Characteristics of Gas-Source MBE-Grown n-AlxGa1-xAs (x=0-0.28) Doped Using Disilane  

Science Journals Connector (OSTI)

Si doping using uncracked disilane (Si2H6) in gas-source molecular beam epitaxy of n-AlxGa1-xAs (x=0-0.28) using triethyl gallium, triethyl aluminum, and arsine was studied in a carrier concentration from 5 ? 1017 to 2 ? 1018 cm-3. We found that (1) the Si atomic concentration of AlGaAs is proportional to the Si2H6 flow rate, and decreases with increasing Al content at a constant Si2H6 flow rate, and (2) the carrier concentration of AlGaAs shows a square-root dependence on the Si atomic concentration incorporated.

Toshio Fujii; Adarsh Sandhu; Hideyasu Ando; Yuji Kataoka; Hideaki Ishikawa

1990-01-01T23:59:59.000Z

257

ALS Visitors  

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

ALS Visitors Print ALS Visitors Print ALS staff members host a variety of scientific, educational, government, and community-related tours each month. November 2013 poneman U.S. Deputy Secretary of Energy Daniel Poneman visited Berkeley Lab on Friday, Nov. 15, during a brief stay in the Bay Area. Glenn Mara of the University of California Office of the President and Aundra Richards of the DOE Berkeley Site Office joined Deputy Laboratory Director Horst Simon's welcome. They updated Poneman on the lab's future initiatives and current capital projects and heard briefings on cyber security, computing, and the Joint BioEnergy Institute. As second-in-command at DOE, Poneman is responsible for assisting the Secretary of Energy in the management and operations of the agency and acting on his behalf when necessary.During his tour of the ALS, Poneman (right) spoke with Ken Goldberg (Materials Sciences Division) at the CXRO beamline.

258

Al Weinrub  

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

Al Weinrub Al Weinrub Author, "COMMUNITY POWER: Decentralized Renewable Energy in California" Member, Sierra Club California Clean Energy-Climate CommitteeMember, Steering Committee, Bay Area Clean Energy Alliance al.weinrub@comcast.net This speaker was a visiting speaker who delivered a talk or talks on the date(s) shown at the links below. This speaker is not otherwise associated with Lawrence Berkeley National Laboratory, unless specifically identified as a Berkeley Lab staff member. Al Weinrub is a member of the Sierra Club California Energy-Climate Committee and serves on the Steering Committee of the Bay Area's Local Clean Energy Alliance. He is the author of COMMUNITY POWER: Decentralized Renewable Energy in California (http://www.localcleanenergy.org/Community-Power-Publication)

259

EuAl2 at pressures up to 41 GPa: A localized magnet exhibiting highly nonlinear electronic effects  

Science Journals Connector (OSTI)

Eu151 Mössbauer studies under hydrostatic pressures up to 41 GPa coupled to x-ray diffraction measurements show that—contrary to expectations—the 4f electrons in EuAl2 remain fully localized even under a reduction of unit cell volume of ?30%. However, strongly nonlinear effects are observed for the conduction electron polarization, for the s-electron density ?(0) at the Eu151 nucleus, the Néel temperature TN, and the transferred hyperfine field hyperbolically; TN and Bthf connected to ?(0). The latter results can be described quantitatively within the RKKY formalism.

A. Gleissner; W. Potzel; J. Moser; G. M. Kalvius

1993-03-29T23:59:59.000Z

260

Approved for public release; distribution is unlimited. ERDC TN-DOER-E34  

E-Print Network (OSTI)

industry seismic surveys and construction activities such as pile-driving (Richardson et al. 1995). In fact, the scant scientific literature pertaining to effects of underwater sound on fishes and other aquatic underwater sounds and their potential impacts on fishes or species with threatened or endangered status

US Army Corps of Engineers

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While these samples are representative of the content of NLEBeta,
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261

IEEE TRANSACTIONS ON MAGNETICS, VOL. 38, NO. 4, JULY 2002 1803 New Ni5Al3 Underlayer for Longitudinal  

E-Print Network (OSTI)

IEEE TRANSACTIONS ON MAGNETICS, VOL. 38, NO. 4, JULY 2002 1803 New Ni5Al3 Underlayer--We describe a new Ni5Al3 underlayer for high-den- sity longitudinal magnetic recording. The Ni5Al3 underlayer has the FCC derivative Ga3Pt5 structure. The Ni5Al3 (221) plane has good lattice match with the Co

Laughlin, David E.

262

E-Print Network 3.0 - al-fe alloys strukturnyj Sample Search...  

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

Theory NiAl CoAl FeAl CoGa PdIn VT,1 A Q M 1, 0 128, 0 144... , with transition-metal vacancies (VT) for T-deficient ... Source: Collins, Gary S. - Department of Physics...

263

Pulsed laser deposition growth of heteroepitaxial YBa2Cu3O7/La0.67Ca0.33MnO3 superlattices on NdGaO3 and Sr0.7La0.3Al0.65Ta0.35O3 substrates  

SciTech Connect

Heteroepitaxial superlattices of [YBa{sub 2}Cu{sub 3}O{sub 7}(n)/La{sub 0.67}Ca{sub 0.33}MnO{sub 3}(m)]{sub x} (YBCO/LCMO), where n and m are the number of YBCO and LCMO monolayers and x the number of bilayer repetitions, have been grown with pulsed laser deposition on NdGaO{sub 3} (110) and Sr{sub 0.7}La{sub 0.3}Al{sub 0.65}Ta{sub 0.35}O{sub 3} (001). These substrates are well lattice matched with YBCO and LCMO and, unlike the commonly used SrTiO{sub 3}, they do not give rise to complex and uncontrolled strain effects at low temperature. The growth dynamics and the structure have been studied in situ with reflection high-energy electron diffraction and ex situ with scanning transmission electron microscopy, x-ray diffraction, and neutron reflectometry. The individual layers are found to be flat and continuous over long lateral distances with sharp and coherent interfaces and with a well-defined thickness of the individual layer. The only visible defects are antiphase boundaries in the YBCO layers that originate from perovskite unit-cell height steps at the interfaces with the LCMO layers. We also find that the first YBCO monolayer at the interface with LCMO has an unusual growth dynamics and is lacking the CuO chain layer, while the subsequent YBCO layers have the regular Y-123 structure. Accordingly, the CuO{sub 2} bilayers at both the LCMO/YBCO and the YBCO/LCMO interfaces are lacking one of their neighboring CuO chain layers and, thus, half of their hole-doping reservoir. Nevertheless, from electric transport measurements on a superlattice with n = 2 we obtain evidence that the interfacial CuO{sub 2} bilayers remain conducting and even exhibit the onset of a superconducting transition at very low temperature. Finally, we show from dc magnetization and neutron reflectometry measurements that the LCMO layers are strongly ferromagnetic.

Malik, V. K. [University of Fribourg; Marozau, I. [University of Fribourg; Das, S. [University of Fribourg; Doggett, B. [University of Fribourg; Satapathy, D. K. [University of Fribourg; Uribe-Laverde, M. A. [University of Fribourg; Biskup, Nevenko [ORNL; Varela del Arco, Maria [ORNL; Schneider, C. W. [Paul Scherrer Institut, Villigen, Switzerland; Marcelot, C. [Paul Scherrer Institut, Villigen, Switzerland; Stahn, J. [Paul Scherrer Institut, Villigen, Switzerland; Bernhard, C. [University of Fribourg

2012-01-01T23:59:59.000Z

264

Definitive evidence of interlayer coupling between Ga{sub 1-x}Mn{sub x}As layers separated by a nonmagnetic spacer  

SciTech Connect

We have used polarized neutron reflectometry to study the structural and magnetic properties of the individual layers in a series of AlGaAs:Be/Ga{sub 1-x}Mn{sub x}As/GaAs/Ga{sub 1-x}Mn{sub x}As multilayer samples. Structurally, we observe that the samples are virtually identical except for the GaAs spacer thickness (which varies from 3 to 12 nm), and confirm that the spacers contain little or no Mn. Magnetically, we observe that for the sample with the thickest spacer layer, the Ga{sub 1-x}Mn{sub x}As layer adjacent to the Be-doped AlGaAs cap has a temperature dependent magnetization very different from that of the other Ga{sub 1-x}Mn{sub x}As layer. However, as the spacer layer thickness is reduced, the temperature dependent magnetizations of the two Ga{sub 1-x}Mn{sub x}As layers become progressively more similar--a trend we find to be independent of the crystallographic direction along which spins are magnetized. These results definitively show that Ga{sub 1-x}Mn{sub x}As layers can couple across a nonmagnetic spacer and that such coupling depends on spacer thickness.

Kirby, B. J.; Borchers, J. A.; Liu, X.; Ge, Z.; Cho, Y. J.; Dobrowolska, M.; Furdyna, J. K. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

2007-11-15T23:59:59.000Z

265

RECIPIENT:Gwinnett Co, GA  

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

Gwinnett Co, GA Gwinnett Co, GA u.s DEPARUIENT OFENllRGY EERE PROJECT MANAGEMENT CENTER NllPA DETERl\JINATION PROJECr TITLE: Gwinnett Co, GA EEC8G Page I or2 STATE: GA Funding Opportunity Announcement Number Procu~ment Instrument Number N[PA Control Number CID Number DE-EEOOOOS05.005 0 Based on my review ortbe information concerning tbe proposed action, as NEPA Compliance Officer (authorized under DOE Order 4SI.IA), I bave made the following determination: ex, EA, EIS APPENDIX AND NUMBER: Description: 8 5.1 Actions to conserve energy, demonstrate potential energy conservation, and promote energy-efficiency that do not increase the indoor concentrations of potentially harmful substances. These actions may involve financial and technical assistance to individuals (such as builders, owners, consultants, designers), organizations (such as utilities), and state

266

Novel GaAs Devices  

Science Journals Connector (OSTI)

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

Michael Shur

1987-01-01T23:59:59.000Z

267

1D-1D tunneling between vertically coupled GaAs/AlGaAs quantum wires.  

SciTech Connect

We report low-dimensional transport and tunneling in an independently contacted vertically coupled quantum wire system, with a 7.5 nm barrier between the wires. The derivative of the linear conductance shows evidence for both single wire occupation and coupling between the wires. This provides a map of the subband occupation that illustrates the control that we have over the vertically coupled double quantum wires. Preliminary tunneling results indicate a sharp 1D-1D peak in conjunction with a broad 2D-2D background signal. This 1D-1D peak is sensitively dependent on the top and bottom split gate voltage.

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

2004-07-01T23:59:59.000Z

268

Capacitance hysteresis in GaN/AlGaN heterostructures L. E. Byrum,1  

E-Print Network (OSTI)

Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, USA 2 NDP Optronics

Matsik, Steven G.

269

GaN/AlGaN heterojunction infrared detector responding in 814 and 2070 m ranges  

E-Print Network (OSTI)

, Georgia State University, Atlanta, Georgia 30303 S. G. Matsik NDP Optronics LLC, Mableton, Georgia 30126 A

Perera, A. G. Unil

270

Electron microscopy of GaAs/AlGaAs quantum cascade laser  

Science Journals Connector (OSTI)

The quantum cascade laser (QCL) is based on a different principle comparing to bipolar semiconductor lasers, because it uses only one type of ... — electrons and therefore is called an unipolar laser.

A. ?aszcz; J. Ratajczak; A. Czerwinski…

2008-01-01T23:59:59.000Z

271

GaAs/AlGaAs nanostructured composites for free-space and integrated optical devices  

E-Print Network (OSTI)

ion beam etching with SU-8 as mask," Optical Engineering,ion beam etching with SU-8 as mask,” Optical Engineering,

Tsai, Chia-Ho

2006-01-01T23:59:59.000Z

272

ALS Visitors  

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

Quick Facts Quick Facts ALS Visitors Print ALS staff members host a variety of scientific, educational, government, and community-related tours each month. November 2013 poneman U.S. Deputy Secretary of Energy Daniel Poneman visited Berkeley Lab on Friday, Nov. 15, during a brief stay in the Bay Area. Glenn Mara of the University of California Office of the President and Aundra Richards of the DOE Berkeley Site Office joined Deputy Laboratory Director Horst Simon's welcome. They updated Poneman on the lab's future initiatives and current capital projects and heard briefings on cyber security, computing, and the Joint BioEnergy Institute. As second-in-command at DOE, Poneman is responsible for assisting the Secretary of Energy in the management and operations of the agency and acting on his behalf when necessary.During his tour of the ALS, Poneman (right) spoke with Ken Goldberg (Materials Sciences Division) at the CXRO beamline.

273

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

274

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

SciTech Connect

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

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

2013-12-16T23:59:59.000Z

275

Identification of the gallium vacancy-oxygen pair defect in GaN  

SciTech Connect

Cation vacancies like V{sub Ga}, V{sub Al} and their complexes with oxygen are predicted to be abundant in III-nitrides and to play an important role in nonradiative recombination. Appearing in triple or double negatively charged states, they are not paramagnetic and have not so far been detected by magnetic resonance even under illumination. In this Brief Report, we demonstrate an efficient way to make cation vacancy defects in GaN detectable by electron paramagnetic resonance and present our identification of the V{sub Ga}O{sub N} pair in GaN which is the model material for the III-nitrides and their alloys.

Son, N. T.; Hemmingsson, C. G.; Janzen, E. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Paskova, T.; Evans, K. R. [Kyma Technologies Inc., 8829 Midway West Road, Raleigh, North Carolina 27617 (United States); Usui, A. [R and D Division, Furukawa Co., Ltd., Tsukuba, Ibaraki 305-0856 (Japan); Morishita, N.; Ohshima, T. [Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Isoya, J. [Graduate School of Library, Information and Media Studies, University of Tsukuba, Tsukuba, Ibaraki 305-8550 (Japan); Monemar, B. [Department of Physics, Chemistry and Biology, Linkoeping University, SE-581 83 Linkoeping (Sweden); Nanometer Structure Consortium, Lund University, P.O. Box 118, S-221 00 Lund (Sweden)

2009-10-15T23:59:59.000Z

276

New GaInP/GaAs/GaInAs, Triple-Bandgap, Tandem Solar Cell for High-Efficiency Terrestrial Concentrator Systems  

SciTech Connect

GaInP/GaAs/GaInAs three-junction cells are grown in an inverted configuration on GaAs, allowing high quality growth of the lattice matched GaInP and GaAs layers before a grade is used for the 1-eV GaInAs layer. Using this approach an efficiency of 37.9% was demonstrated.

Kurtz, S.; Wanlass, M.; Kramer, C.; Young, M.; Geisz, J.; Ward, S.; Duda, A.; Moriarty, T.; Carapella, J.; Ahrenkiel, P.; Emery. K.; Jones, K.; Romero, M.; Kibbler, A.; Olson, J.; Friedman, D.; McMahon, W.; Ptak, A.

2005-11-01T23:59:59.000Z

277

GaSb/GaAs type II quantum dot solar cells for enhanced infrared spectral response  

E-Print Network (OSTI)

GaSb/GaAs type II quantum dot solar cells for enhanced infrared spectral response R. B Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 Received 27 infrared spectral response of GaAs-based solar cells that incorporate type II GaSb quantum dots QDs formed

Jalali. Bahram

278

Plasmonic nanoparticle enhanced photocurrent in GaN/InGaN/GaN quantum well solar cells  

E-Print Network (OSTI)

Plasmonic nanoparticle enhanced photocurrent in GaN/InGaN/GaN quantum well solar cells Imogen M of Applied Physics, California Institute of Technology, Pasadena, California 91125, USA 2 Semiconductor Nanoscience Institute, California Institute of Technology, Pasadena, California 91125, USA Received 26

Atwater, Harry

279

Regulators and computations of Mahler measures Mahler Measure in Mobile, University of South Alabama, Mobile, AL  

E-Print Network (OSTI)

�Wigner dilogarithm, D(x) := Im(Li2(x)) + arg(1 - x) log |x| which satisfies the well-known five-term relation D Alabama, Mobile, AL January 5th, 2006 Matilde N. Lal�in Mahler measure Definition 1 For P C[x�1 1 , . . . , x�1 n ], the (logarithmic) Mahler measure is defined by m(P) = 1 (2i)n Tn log |P(x1, . . . , xn)| dx

Leclercq, Remi

280

AL. I  

Office of Legacy Management (LM)

AL. I AL. I Department of Energy Washington, DC 20545 OCT 13 Vii87 Mr. John T. Shields A214 National Fertilizer Development Center Tennessee Valley Authority Muscle Shoals, Alabama 35660 Dear Mr. Shields: As you may know, the Department of Energy (DOE) is evaluating the radiological condition of sites that were utilized under the Manhattan Engineer District and the Atomic Energy Commission (AEC) during the early years of nuclear development to determine whether they need remedial action and whether the Department has authority to perform such action. AEC work at the TVA during the period 1951 through 1955 involved the development of a process to recover uranium from the production of phosphate fertilizer. A laboratory and pilot plant were operated at the site, but very little

Note: This page contains sample records for the topic "tn al ga" 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

Repulsive interaction in the macroscopically ordered exciton state in GaAs?AlxGa1?xAs coupled quantum well structures  

Science Journals Connector (OSTI)

The macroscopically ordered exciton state (MOES)—a periodic array of beads with spatial order on a macroscopic length—appears in the external exciton rings in coupled GaAs?(Al,Ga)As quantum wells at low temperatures below a few Kelvin. Here, we report on the experimental study of the interaction in the MOES. The exciton photoluminescence energy varies in concert with the intensity along the circumference of the ring, with the largest energy found in the brightest regions. This shows that the MOES is characterized by the repulsive interaction and is not driven by the attractive interaction.

Sen Yang, A. V. Mintsev, A. T. Hammack, L. V. Butov, and A. C. Gossard

2007-01-17T23:59:59.000Z

282

GaAs–based quantum cascade lasers  

Science Journals Connector (OSTI)

...N. Murdin GaAs-based quantum cascade lasers Sirtori H. Page C. Becker...state-of-the-art of GaAs-based quantum cascade lasers. These new light sources...2000.0739 GaAs-based quantum cascade lasers By C. Sirtori, H. Page...

2001-01-01T23:59:59.000Z

283

Electrical properties of Er-doped In0.53Ga0.47As  

E-Print Network (OSTI)

03C117-3 Burke et al. : Electrical properties of Er-doped InElectrical properties of Er-doped In 0.53 Ga 0.47 As PeterBahk and John E. Bowers Electrical and Computer Engineering

Burke, Peter G.; Lu, Hong; Rudawski, Nicholas G.; Gossard, Arthur G.; Bahk, Je-Hyeong; Bowers, John E.

2011-01-01T23:59:59.000Z

284

Cu(In,Ga)Se2based Photovoltaics: Challenges and Opportunities  

E-Print Network (OSTI)

Cu(In,Ga)Se2­based Photovoltaics: Challenges and Opportunities William Shafarman Institute of Energy Conversion University of Delaware #12;Thin Film Photovoltaics Potential for low cost PV using a Thickness K.Kim, et al., IEEE J. Photovoltaics, 3, 446 (2013). 2 µm, 60 min reaction 1 µm, 25 min reaction 0

Firestone, Jeremy

285

Molecular Beam Epitaxy on Gas Cluster Ion Beam Prepared GaSb Substrates: Towards Improved Surfaces and Interfaces  

SciTech Connect

A key problem in producing mid-infrared optoelectronic and low-power electronic devices in the GaSb material system is the lack of substrates with appropriate surfaces for epitaxial growth. Chemical mechanical polishing (CMP) of GaSb results in surface damage accompanied by tenacious oxides that do not easily desorb. To overcome this, we have developed a process using gas cluster ion beams (GCIB) to remove surface damage and produce engineered surface oxides. In this paper, we present surface modification results on GaSb substrates using O2-, CF4/O2-, and HBr-GCIB processes. X-ray photoelectron spectroscopy of GCIB produced surface layers showed the presence of mixed Ga- and Sb-oxides, with mostly Ga-oxides at the interface, desorbing at temperatures ranging 530°C to 560°C. Cross-sectional transmission electron microscopy of molecular beam epitaxy grown GaSb/AlGaSb layers showed that GCIB surfaces yielded smooth defect free substrate to epi transitions as compared to CMP surfaces. Furthermore, HBr-GCIB surfaces exhibited neither dislocation layers nor discernable interfaces, indicating complete oxide desorbtion prior to epigrowth on a clean single crystal template. Atomic force microscopy of GCIB epilayers exhibited smooth surfaces with characteristic step-terrace formations comprising monatomic steps and wide terraces. The HBr-GCIB process can be easily adapted to a large scale manufacturing process for epi-ready GaSb.

Krishnaswami, Kannan; Shivashankar, Vangala; Dauplaise, Helen; Allen, Lisa; Dallas, Gordon; Bakken, Daniel; Bliss, David; Goodhue, William

2008-04-01T23:59:59.000Z

286

Epitaxial growth of metastable multiferroic AlFeO{sub 3} film on SrTiO{sub 3} (111) substrate  

SciTech Connect

GaFeO{sub 3}-type AlFeO{sub 3} is consisted of oxygen octahedra and tetrahedra containing Al and Fe ions and is known to have a non-centrosymmetric polar structure with space group Pna2{sub 1}. We tried to grow epitaxial GaFeO{sub 3}-type AlFeO{sub 3} films on SrTiO{sub 3} (111) substrates by pulsed laser deposition technique. Both the atomic arrangement of close-packed and the atomic distance of the substrate surface played important roles in stabilizing GaFeO{sub 3}-type AlFeO{sub 3} on the substrate. Piezoresponse force microscopy measurements clearly showed that GaFeO{sub 3}-type AlFeO{sub 3} films have ferroelectricity at room temperature. In addition, AlFeO{sub 3} film also showed pinched-like hysteresis loop with T{sub N}???317?K.

Hamasaki, Yosuke; Shimizu, Takao; Taniguchi, Hiroki; Taniyama, Tomoyasu; Yasui, Shintaro; Itoh, Mitsuru, E-mail: itoh.m.aa@m.titech.ac.jp [Materials and Structures Laboratory, Tokyo Institute of Technology, 4259-J2-19 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

2014-02-24T23:59:59.000Z

287

Observation of photoluminescence from Al1 xInxN heteroepitaxial films grown by metalorganic vapor phase epitaxy  

E-Print Network (OSTI)

Observation of photoluminescence from Al1 xInxN heteroepitaxial films grown by metalorganic vapor have observed photoluminescence of Al1 xInxN films. The films were grown on GaN by atmospheric pressure-temperature deposited AlN buffer layer. Photoluminescence, absorption, and x-ray diffraction measurements have shown

Wetzel, Christian M.

288

Coulomb excitation of 73Ga  

E-Print Network (OSTI)

The B(E2; Ii -> If) values for transitions in 71Ga and 73Ga were deduced from a Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using post-accelerated beams of 71,73Ga at the REX-ISOLDE on-line isotope mass separator facility. The emitted gamma rays were detected by the MINIBALL-detector array and B(E2; Ii->If) values were obtained from the yields normalized to the known strength of the 2+ -> 0+ transition in the 120Sn target. The comparison of these new results with the data of less neutron-rich gallium isotopes shows a shift of the E2 collectivity towards lower excitation energy when adding neutrons beyond N = 40. This supports conclusions from previous studies of the gallium isotopes which indicated a structural change in this isotopical chain between N = 40 and N = 42. Combined with recent measurements from collinear laser spectroscopy showing a 1/2- spin and parity for the ground state, the extracted results revealed evidence for a 1/2-; 3/2- doublet near the ground state in 73 31Ga42 differing by at most 0.8 keV in energy.

J. Diriken; I. Stefanescu; D. Balabanski; N. Blasi; A. Blazhev; N. Bree; J. Cederkäll; T. E. Cocolios; T. Davinson; J. Eberth; A. Ekström; D. V. Fedorov; V. N. Fedosseev; L. M. Fraile; S. Franchoo; G. Georgiev; K. Gladnishki; M. Huyse; O. V. Ivanov; V. S. Ivanov; J. Iwanicki; J. Jolie; T. Konstantinopoulos; Th. Kröll; R. Krücken; U. Köster; A. Lagoyannis; G. Lo Bianco; P. Maierbeck; B. A. Marsh; P. Napiorkowski; N. Patronis; D. Pauwels; P. Reiter; M. Seliverstov; G. Sletten; J. Van de Walle; P. Van Duppen; D. Voulot; W. B. Walters; N. Warr; F. Wenander; K. Wrzosek

2010-10-13T23:59:59.000Z

289

GaInAsSb/A1GaAsSb/Sb Thermophotovoltaic Devices With an Internal Back-Surface Reflector Formed by Wafer Bonding  

SciTech Connect

A novel implementation for GAInAsSb/AlGaAsSb/GaSb TPV cells with an internal back-surface reflector (BSR) formed by wafer bonding to GaAs is demonstrated. The SiO{sub x}/Ti/Au internal BSR enhances optical absorption within the device, while the dielectric layer provides electrical isolation. This configuration has the potential to improve TPV device performance; is compatible with monolithic series-interconnection of TPV cells for building voltage; and can mitigate the requirements of filters used for front-surface spectral control. At a short-circuit density of 0.4 A/cm{sup 2}, the open-circuit voltage of a single TPV cell is 0.2 V, compared to 0.37 and 1.8 V for 2- and 10-junction series-interconnected TPV cells, respectively.

C.A. Wang; R.K. Huang; D.A. Shiau; M.K. Connors; P.G. Murphy; P.W. O'brien; A.C. Anderson; D.M. DePoy; G. Nichols; M.N. Palmasiano

2002-12-18T23:59:59.000Z

290

Charakterisierung und Präparation von GaN und Herstellung von In-Plane-Gate Transistoren in AlxGa1-xN/GaN Heterostrukturen.  

E-Print Network (OSTI)

??Gegenstand der Arbeit sind GaN-Volumenmaterial und AlxGa1-xN/GaN HEMTs (high electron mobility transistor), welche ein zweidimensionales Elektronengas (2DEG) besitzen. Die Materialien wurden durch elektrische Messungen, insbesondere… (more)

Ebbers, André

2003-01-01T23:59:59.000Z

291

Staff Member, Staff Member, and Staff Supervisor, respectively, Oak Ridge National Laboratory, Engineering Technology Division, Oak Ridge, TN 37831-8066.  

E-Print Network (OSTI)

1 Staff Member, Staff Member, and Staff Supervisor, respectively, Oak Ridge National Laboratory, Engineering Technology Division, Oak Ridge, TN 37831-8066. D. E. Welch1 , L. M. Hively1 , R. F. Holdaway1 STP Conshohocken, PA, 2002. Abstract Oak Ridge National Laboratory has developed a new technique to monitor

Hively, Lee M.

292

The Funk Transform as a Penrose Transform T.N. Bailey M.G. Eastwood A.R. Gover L.J. Mason  

E-Print Network (OSTI)

The Funk Transform as a Penrose Transform T.N. Bailey M.G. Eastwood A.R. Gover L.J. Mason December 2, 1999 Abstract The Funk transform is the integral transform from the space of smooth even this transform as a limit in a certain sense of the Penrose transform from C P 2 to C P \\Lambda 2 . We exploit

Gover, Rod

293

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

294

Development of an electronic device quality aluminum antimonide (AlSb) semiconductor for solar cell applications  

DOE Patents (OSTI)

Electronic device quality Aluminum Antimonide (AlSb)-based single crystals produced by controlled atmospheric annealing are utilized in various configurations for solar cell applications. Like that of a GaAs-based solar cell devices, the AlSb-based solar cell devices as disclosed herein provides direct conversion of solar energy to electrical power.

Sherohman, John W; Yee, Jick Hong; Combs, III, Arthur W

2014-11-11T23:59:59.000Z

295

Composition dependence of interband transition intensities in GaPN, GaAsN, and GaPAs alloys  

Science Journals Connector (OSTI)

Using large (512-atom) pseudopotential supercell calculations, we have investigated the composition dependence of the momentum matrix element Mv,c for transitions between the valence-band maximum and the conduction-band minimum of three semiconductor alloys:?GaP1-xNx and GaAs1-xNx, exhibiting large chemical and size differences between their alloyed elements, and GaP1-xAsx, which is a weakly perturbed alloy. In the composition ranges where these alloys have a direct band gap, we find that (i) in GaP1-xAsx, Mv,c is large (like the virtual-crystal value) and nearly composition independent; (ii) in GaAs1-xNx, Mv,c is strongly composition dependent: large for small x and small for large x; and (iii) in GaP1-xNx, Mv,c is only slightly composition dependent and is significantly reduced relative to the virtual-crystal value. The different behavior of GaP1-xAsx, GaP1-xNx, and GaAs1-xNx is traced to the existence/absence of impurity levels at the dilute alloy limits: (a) there are no gap-level impurity states at the x?1 or x?0 limits of GaP1-xAsx, (b) an isolated As impurity in GaN (GaN?:As) has a deep band gap impurity level but no deep impurity state is found for N in GaAs, and (c) GaN?:P exhibits a P-localized deep band-gap impurity state and GaP?:N has an N-localized resonant state. The existence of deep levels leads to wave-function localization in real space, thus to a spectral spread in momentum space and to a reduction of Mv,c. These impurity levels are facilitated by atomic relaxations, as evident by the fact that unrelaxed GaN?:As and GaN?:P, show no deep levels, have extended wave functions, and have large interband transition elements.

L. Bellaiche; Su-Huai Wei; Alex Zunger

1997-10-15T23:59:59.000Z

296

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

SciTech Connect

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

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

2013-12-04T23:59:59.000Z

297

Ultra-Thin, Triple-Bandgap GaInP/GaAs/GaInAs Monolithic Tandem Solar Cells  

SciTech Connect

The performance of state-of-the-art, series-connected, lattice-matched (LM), triple-junction (TJ), III-V tandem solar cells could be improved substantially (10-12%) by replacing the Ge bottom subcell with a subcell having a bandgap of {approx}1 eV. For the last several years, research has been conducted by a number of organizations to develop {approx}1-eV, LM GaInAsN to provide such a subcell, but, so far, the approach has proven unsuccessful. Thus, the need for a high-performance, monolithically integrable, 1-eV subcell for TJ tandems has remained. In this paper, we present a new TJ tandem cell design that addresses the above-mentioned problem. Our approach involves inverted epitaxial growth to allow the monolithic integration of a lattice-mismatched (LMM) {approx}1-eV GaInAs/GaInP double-heterostructure (DH) bottom subcell with LM GaAs (middle) and GaInP (top) upper subcells. A transparent GaInP compositionally graded layer facilitates the integration of the LM and LMM components. Handle-mounted, ultra-thin device fabrication is a natural consequence of the inverted-structure approach, which results in a number of advantages, including robustness, potential low cost, improved thermal management, incorporation of back-surface reflectors, and possible reclamation/reuse of the parent crystalline substrate for further cost reduction. Our initial work has concerned GaInP/GaAs/GaInAs tandem cells grown on GaAs substrates. In this case, the 1-eV GaInAs experiences 2.2% compressive LMM with respect to the substrate. Specially designed GaInP graded layers are used to produce 1-eV subcells with performance parameters nearly equaling those of LM devices with the same bandgap (e.g., LM, 1-eV GaInAsP grown on InP). Previously, we reported preliminary ultra-thin tandem devices (0.237 cm{sup 2}) with NREL-confirmed efficiencies of 31.3% (global spectrum, one sun) (1), 29.7% (AM0 spectrum, one sun) (2), and 37.9% (low-AOD direct spectrum, 10.1 suns) (3), all at 25 C. Here, we include recent results of testing similar devices under the concentrated AMO spectrum, and also present the first demonstration of a high-efficiency, ultra-thin GaInP/GaAs/GaInAs tandem cell processed on a flexible kapton handle.

Wanlass, M. W.; Ahrenkiel, S. P.; Albin, D. S.; Carapella, J. J.; Duda, A.; Emery, K.; Geisz, J. F.; Jones, K.; Kurtz, S.; Moriarty, T.; Romero, M. J.

2007-02-01T23:59:59.000Z

298

Transportation of a 451 ton generator stator and a 234 ton generator rotor from Hartsville, TN, to Los Alamos, NM  

SciTech Connect

A 1430 MVA steam turbine generator was acquired from a cancelled nuclear power plant in Tennessee to be used as the pulsed power and energy storage unit for the Confinement Physics Research Facility being built at Los Alamos, NM. The transportation from Hartsville, near Nashville, TN, to Los Alamos, NM, of the two largest single pieces of the generator, a 451 t stator and a 234 t rotor presented a special challenge. Details of the move, by barge from Hartsville to Catoosa, near Tulsa, OK, by rail from Catoosa to Lamy, near Santa Fe, NM, and by road from Lamy to Los Alamos are described. The greatest difficulty of the successful move was the crossing of the Rio Grande river on an existing reinforced concrete bridge. The two-lane wide road transporters for the stator and rotor were fitted with outriggers to provide a four-lane wide vehicle, thus spreading the load over the entire bridge width and meeting acceptable load distribution and bridge safety factors. 2 refs., 6 figs.

Boenig, H.J.; Rogers, J.D.; McLelland, G.R.; Pelts, C.T. (Los Alamos National Lab., NM (USA); McLelland Engineering, Dallas, TX (USA); Reliance Crane and Rigging, Inc., Phoenix, AZ (USA))

1989-01-01T23:59:59.000Z

299

100000241,1,1,1,1,21734296,"AL",10610,"Albertville Municipal...  

U.S. Energy Information Administration (EIA) Indexed Site

,9,24,1,1,522207,"TN",8026,"Newport City of",2000 4700013933,1,1,1,1,43686453,"TN",10610,"Oak Ridge City of",2000 4700013933,1,2,1,1,2398749,"TN",10620,"Oak Ridge City of",2000...

300

Princeton Plasma Physics Lab - General Atomics (GA)  

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

general-atomics-ga General general-atomics-ga General Atomics en The Scorpion's Strategy: "Catch and Subdue" http://www.pppl.gov/node/1132

American Fusion News Category: 
Note: This page contains sample records for the topic "tn al ga" 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

Room temperature continuous wave InGaAsN quantum well vertical cavity lasers emitting at 1.3 um  

SciTech Connect

Selectively oxidized vertical cavity lasers emitting at 1294 nm using InGaAsN quantum wells are reported for the first time which operate continuous wave at and above room temperature. The lasers employ two n-type Al{sub 0.94}Ga{sub 0.06}As/GaAs distributed Bragg reflectors each with a selectively oxidized current aperture adjacent to the optical cavity, and the top output mirror contains a tunnel junction to inject holes into the active region. Continuous wave single mode lasing is observed up to 55 C. These lasers exhibit the longest wavelength reported to date for vertical cavity surface emitting lasers grown on GaAs substrates.

CHOQUETTE,KENT D.; KLEM,JOHN F.; FISCHER,ARTHUR J.; SPAHN,OLGA B.; ALLERMAN,ANDREW A.; FRITZ,IAN J.; KURTZ,STEVEN R.; BREILAND,WILLIAM G.; SIEG,ROBERT M.; GEIB,KENT M.; SCOTT,J.W.; NAONE,R.L.

2000-06-05T23:59:59.000Z

302

Ultra-low resistance ohmic contacts to GaN with high Si doping concentrations grown by molecular beam epitaxy  

SciTech Connect

Ti/Al/Ni/Au ohmic contacts were formed on heavily doped n{sup +} metal-polar GaN samples with various Si doping concentrations grown by molecular beam epitaxy. The contact resistivity (R{sub C}) and sheet resistance (R{sub sh}) as a function of corresponding GaN free carrier concentration (n) were measured. Very low R{sub C} values (<0.09 {Omega} mm) were obtained, with a minimum R{sub C} of 0.035 {Omega} mm on a sample with a room temperature carrier concentration of {approx}5 Multiplication-Sign 10{sup 19} cm{sup -3}. Based on the systematic study, the role of R{sub C} and R{sub sh} is discussed in the context of regrown n{sup +} GaN ohmic contacts for GaN based high electron mobility transistors.

Afroz Faria, Faiza; Guo Jia; Zhao Pei; Li Guowang; Kumar Kandaswamy, Prem; Wistey, Mark; Xing Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2012-07-16T23:59:59.000Z

303

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

SciTech Connect

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

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

2013-11-04T23:59:59.000Z

304

Neutron Scattering Measurements of Spatially Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280??K)  

Science Journals Connector (OSTI)

We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic order in semiconducting K0.85Fe1.54Se2 (TN=280??K). We show that the spin-wave spectra can be accurately described by an effective Heisenberg Hamiltonian with highly anisotropic inplane couplings at T=5??K. At high temperature (T=300??K) above TN, short-range magnetic correlation with anisotropic correlation lengths are observed. Our results suggest that, despite the dramatic difference in the Fermi surface topology, the inplane anisotropic magnetic couplings are a fundamental property of the iron-based compounds; this implies that their antiferromagnetism may originate from local strong correlation effects rather than weak coupling Fermi surface nesting.

Jun Zhao; Yao Shen; R.?J. Birgeneau; Miao Gao; Zhong-Yi Lu; D.-H. Lee; X.?Z. Lu; H.?J. Xiang; D.?L. Abernathy; Y. Zhao

2014-04-30T23:59:59.000Z

305

Neutron Scattering Measurements of Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280K)  

SciTech Connect

We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic (AFM) order in semiconducting K0.85Fe1.54Se2 (TN=280 K). We show that the spin wave spectra can be accurately described by an effective Heisenberg Hamiltonian with highly anisotropic in-plane couplings at T= 5 K. At high temperature (T= 300 K) above TN, short range magnetic correlation with anisotropic correlation lengths are observed. Our results suggest that, despite the dramatic difference in the Fermi surface topology, the in-plane anisotropic magnetic coupings are a fundamental property of the iron based compounds; this implies that their antiferromagnetism may originate from local strong correlation effects rather than weak coupling Fermi surface nesting.

Abernathy, Douglas L [ORNL] [ORNL; Birgeneau, R. J. [University of California, Berkeley] [University of California, Berkeley; Gao, Miao [Renmin University of China] [Renmin University of China; Lu, Zhong-Yi [Renmin University of China] [Renmin University of China; Zhao, Jun [Fudan University, China] [Fudan University, China; Zhao, Y. [NIST and Univ. of MD] [NIST and Univ. of MD

2014-01-01T23:59:59.000Z

306

GaInP/GaAs/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators  

SciTech Connect

We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure through the use of transparent compositionally graded layers. The current work concerns an inverted, series-connected, triple-bandgap, GaInP (LM, 1.87 eV)/GaAs (LM, 1.42 eV)/GaInAs (LMM, {approx}1 eV) device structure grown on a GaAs substrate. Ultra-thin tandem devices are fabricated by mounting the epiwafers to pre-metallized Si wafer handles and selectively removing the parent GaAs substrate. The resulting handle-mounted, ultra-thin tandem cells have a number of important advantages, including improved performance and potential reclamation/reuse of the parent substrate for epitaxial growth. Additionally, realistic performance modeling calculations suggest that terrestrial concentrator efficiencies in the range of 40-45% are possible with this new tandem cell approach. A laboratory-scale (0.24 cm2), prototype GaInP/GaAs/GaInAs tandem cell with a terrestrial concentrator efficiency of 37.9% at a low concentration ratio (10.1 suns) is described, which surpasses the previous world efficiency record of 37.3%.

Wanlass, M. W.; Ahrenkiel, S. P.; Albin, D. S.; Carapella, J. J.; Duda, A.; Emery, K.; Geisz, J. F.; Jones, K.; Kurtz, S.; Moriarty, T.; Romero, M. J.

2005-08-01T23:59:59.000Z

307

Structural and optical properties of InGaN–GaN nanowire heterostructures grown by molecular beam epitaxy  

InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaN to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, ?-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.

Limbach, F. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jülich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Gotschke, T. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jülich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Stoica, T. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jülich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Calarco, R. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jülich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Sutter, E. [Brookhaven National Lab., Upton, NY (United States); Ciston, J. [Brookhaven National Lab., Upton, NY (United States); Cusco, R. [Consell Superior d'Investigacions Cientifiques (CSIC), Barcelona (Spain); Artus, L. [Consell Superior d'Investigacions Cientifiques (CSIC), Barcelona (Spain); Kremling, S. [Univ. Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wurzburg (Germany); Hofling, S. [Univ. Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wurzburg (Germany); Worschech, L. [Univ. Wurzburg, Wilhelm Conrad Rontgen Research Centre Complex Matter Systems, Wurzburg (Germany); Grutzmacher, D. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jülich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany)

2011-01-07T23:59:59.000Z

308

TN_50mwind  

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

Metadata also available as Metadata: IdentificationInformation DataQualityInformation SpatialDataOrganizationInformation SpatialReferenceInformation EntityandAttributeI...

309

Association Nashville, TN  

E-Print Network (OSTI)

-Optimist Views Transhumanism (h+) Pic of kurzweil?pic of ,,when humans transcend...? Pic of movie? Exponential

Berleant, Daniel

310

US SoAtl GA Site Consumption  

Gasoline and Diesel Fuel Update (EIA)

GA GA Site Consumption million Btu $0 $500 $1,000 $1,500 $2,000 $2,500 US SoAtl GA Expenditures dollars ALL ENERGY average per household (excl. transportation) 0 4,000 8,000 12,000 16,000 US SoAtl GA Site Consumption kilowatthours $0 $300 $600 $900 $1,200 $1,500 $1,800 US SoAtl GA Expenditures dollars ELECTRICITY ONLY average per household * Site energy consumption (89.5 million Btu) and energy expenditures per household ($2,067) in Georgia are similar to the U.S. household averages. * Per household electricity consumption in Georgia is among the highest in the country, but similar to other states in the South. * Forty-five percent of homes in Georgia were built since 1990, a characteristic typically associated with lower per household consumption. Georgia homes,

311

US SoAtl GA Site Consumption  

U.S. Energy Information Administration (EIA) Indexed Site

GA GA Site Consumption million Btu $0 $500 $1,000 $1,500 $2,000 $2,500 US SoAtl GA Expenditures dollars ALL ENERGY average per household (excl. transportation) 0 4,000 8,000 12,000 16,000 US SoAtl GA Site Consumption kilowatthours $0 $300 $600 $900 $1,200 $1,500 $1,800 US SoAtl GA Expenditures dollars ELECTRICITY ONLY average per household * Site energy consumption (89.5 million Btu) and energy expenditures per household ($2,067) in Georgia are similar to the U.S. household averages. * Per household electricity consumption in Georgia is among the highest in the country, but similar to other states in the South. * Forty-five percent of homes in Georgia were built since 1990, a characteristic typically associated with lower per household consumption. Georgia homes,

312

Vertical minority carrier electron transport in p-type InAs/GaSb type-II superlattices  

E-Print Network (OSTI)

Vertical minority carrier electron transport in p-type InAs/GaSb type-II superlattices G. A. Umana transport J. Appl. Phys. 112, 123715 (2012) Characteristics of built-in polarization potentials Appl. Phys. Lett. 101, 243113 (2012) Thermal stability of the deep ultraviolet emission from Al

Krishna, Sanjay

313

ALS Chemistry Lab  

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

ALS Chemistry Lab Print ALS Chemistry Labs The ALS Chemistry Labs are located in the User Support Building (15-130) and in Building 6 (6-2233)*. These spaces are dedicated for...

314

ALS Chemistry Lab  

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

Safety Safety for Users ALS Chemistry Lab Print ALS Chemistry Labs The ALS Chemistry Labs are located in the User Support Building (15-130) and in Building 6 (6-2233)*. These...

315

Ultra-high frequency photoconductivity decay in GaAs/Ge/GaAs double heterostructure grown by molecular beam epitaxy  

SciTech Connect

GaAs/Ge/GaAs double heterostructures (DHs) were grown in-situ using two separate molecular beam epitaxy chambers. High-resolution x-ray rocking curve demonstrates a high-quality GaAs/Ge/GaAs heterostructure by observing Pendelloesung oscillations. The kinetics of the carrier recombination in Ge/GaAs DHs were investigated using photoconductivity decay measurements by the incidence excitation from the front and back side of 15 nm GaAs/100 nm Ge/0.5 {mu}m GaAs/(100)GaAs substrate structure. High-minority carrier lifetimes of 1.06-1.17 {mu}s were measured when excited from the front or from the back of the Ge epitaxial layer, suggests equivalent interface quality of GaAs/Ge and Ge/GaAs. Wavelength-dependent minority carrier recombination properties are explained by the wavelength-dependent absorption coefficient of Ge.

Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Johnston, S. W. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)] [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Umbel, R. [Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)

2013-03-04T23:59:59.000Z

316

GA Solar | Open Energy Information  

Open Energy Info (EERE)

Solar Solar Jump to: navigation, search Name GA-Solar Place Madrid, Spain Zip 28045 Sector Solar Product Madrid based solar project developer, owned by Spanish industrial group Corporacion Gestamp. Coordinates 40.4203°, -3.705774° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":40.4203,"lon":-3.705774,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

317

Characterization of GaSb/GaAs interfacial misfit arrays using x-ray diffraction  

Science Journals Connector (OSTI)

We report a nondestructive large-area method to characterize dislocation formation at a highly lattice-mismatched interface. The analysis is based on x-ray diffraction and reciprocal space mapping using a standard lab-based diffractometer. We use this technique to identify and analyze a two-dimensional array of 90° misfit dislocations at a GaSb/GaAs interface. The full width at half maximum of the GaSb 004 reciprocal lattice point is shown to decrease with increasing GaSb epilayer thickness as expected from theoretical models. Based on these measurements the variation in the spatial dislocation frequency is calculated to be 1%.

Charles J. Reyner; Jin Wang; Kalyan Nunna; Andrew Lin; Baolai Liang; Mark S. Goorsky; D. L. Huffaker

2011-01-01T23:59:59.000Z

318

Locating essential Escherichia coli genes by using mini-Tn10 transposons: the pdxJ operon.  

Science Journals Connector (OSTI)

...AMC CTC 180IThr Phe Ala Ala Ser Leu ATT AOC GTM CAT TTA COT GAA GO CCC COT CAC ATT ACT...GGT CAT GOC ATT ATT GGT COGT GCA OTG ATM AOC GM CTO 20O4Ala Ala Ile Pro Glu Met His Glu...spaced vertical bars. VOL. 174, 1992 1550 TAKIFF ET AL. TABLE 5. Amino acid composition...

H E Takiff; T Baker; T Copeland; S M Chen; D L Court

1992-03-01T23:59:59.000Z

319

GaN–InGaN LED efficiency reduction from parasitic electron currents in p-GaN  

Science Journals Connector (OSTI)

Abstract This paper presents observations of a previously unidentified source of performance limitation for GaN–InGaN LED devices. While most studies focus on output saturation known as ‘current droop’ from InGaN layer effects, we show an alike influence from p-type GaN’s inherent background electron concentration. p-GaN material was investigated to confirm that, even though the material had an excess of holes, the background electrons were indeed present and were influencing the charge flow across device electrodes. This current does not cross LED heterojunctions but rather drifts toward its proximal device electrode, causing a source of heating while providing no carriers for light emitting recombination. The effects of this current were explored in an LED configuration, whose output showed weak efficiency at very low biases in addition to that from current droop. While the shortcoming under small currents has previously been attributed to electron tunneling across the junction, we propose that the background electrons inside p-GaN could be another explanation.

G. Togtema; V. Georgiev; D. Georgieva; R. Gergova; K.S.A. Butcher; D. Alexandrov

2015-01-01T23:59:59.000Z

320

Exciton relaxation and coupling dynamics in a GaAs/AlxGa1-xAs quantum well and quantum dot ensemble  

Science Journals Connector (OSTI)

Exciton inter- and intra-actions in a GaAs/AlGaAs quantum well (QW) and quantum dot (QD) ensemble are studied using optical two-dimensional Fourier transform spectroscopy. We measure population dynamics for times up to 300 ps and temperatures up to 50 K and observe biexponential decay for both QW and QD excitons, strong QW ? QD relaxation, and weak QD ? QW activation. The population dynamics are modeled using a system of rate equations that incorporate radiative and nonradiative decay, coupling between bright and dark exciton states, and QW ? QD coupling. The fast decay rates are attributed to exciton-bound hole spin flips between optically active and inactive states and are similar for the QW and QDs, indicating excitons are weakly localized in the QDs. The QW ? QD relaxation rate increases with temperature, and QD ? QW excitation is observed at temperatures ?35 K.

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

2011-06-27T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

GaTe semiconductor for radiation detection  

DOE Patents (OSTI)

GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

Payne, Stephen A. (Castro Valley, CA); Burger, Arnold (Nashville, TN); Mandal, Krishna C. (Ashland, MA)

2009-06-23T23:59:59.000Z

322

Microporous Montmorillonites Expanded with Alumina Clusters and M[(?-OH)Cu(?-OCH2CH2NEt2)]6(ClO4)3, (M = Al, Ga, and Fe), or Cr[(?-OCH3)(?-OCH2CH2NEt2)CuCl]3 Complexes  

Science Journals Connector (OSTI)

Mossbauer results have indicated that only Fe3+ in octahedral coordination is present in the iron-containing bi-PILC samples (bi-PILC = bipillared interlayered clays). ... In contrast, the intermediate Al13-PILC structure is least affected when the more stable Cr complex is used. ... Bi-PILC materials containing 2.7?3.4% Cr stable to 500 °C have been obtained. ...

S. M. Thomas; J. A. Bertrand; M. L. Occelli; F. Huggins; S. A. C. Gould

1999-04-09T23:59:59.000Z

323

0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology  

SciTech Connect

Thermophotovoltaic (TPV) diodes fabricated from 0.52eV lattice-matched InGaAsSb alloys are grown by Metal Organic Vapor Phase Epitaxy (MOVPE) on GaSb substrates. 4cm{sup 2} multi-chip diode modules with front-surface spectral filters were tested in a vacuum cavity and attained measured efficiency and power density of 19% and 0.58 W/cm{sup 2} respectively at operating at temperatures of T{sub radiator} = 950 C and T{sub diode} = 27 C. Device modeling and minority carrier lifetime measurements of double heterostructure lifetime specimens indicate that diode conversion efficiency is limited predominantly by interface recombination and photon energy loss to the GaSb substrate and back ohmic contact. Recent improvements to the diode include lattice-matched p-type AlGaAsSb passivating layers with interface recombination velocities less than 100 cm/s and new processing techniques enabling thinned substrates and back surface reflectors. Modeling predictions of these improvements to the diode architecture indicate that conversion efficiencies from 27-30% and {approx}0.85 W/cm{sup 2} could be attained under the above operating temperatures.

MW Dashiell; JF Beausang; G Nichols; DM Depoy; LR Danielson; H Ehsani; KD Rahner; J Azarkevich; P Talamo; E Brown; S Burger; P Fourspring; W Topper; PF Baldasaro; CA Wang; R Huang; M Connors; G Turner; Z Shellenbarger; G Taylor; Jizhong Li; R Marinelli; D Donetski; S Anikeev; G Belenky; S Luryi; DR Taylor; J Hazel

2004-06-09T23:59:59.000Z

324

Direct-bonded GaAs/InGaAs tandem solar cell Katsuaki Tanabe,a  

E-Print Network (OSTI)

Direct-bonded GaAs/InGaAs tandem solar cell Katsuaki Tanabe,a Anna Fontcuberta i Morral,b and Harry, Pasadena, California 91125 Daniel J. Aiken Emcore Photovoltaics, Albuquerque, New Mexico 87123 Mark W. Wanlass National Renewable Energy Laboratory, Golden, Colorado 80401 Received 19 March 2006; accepted 26

Atwater, Harry

325

Polarity determination for MOCVD growth of GaN on Si(111) by convergent beam electron diffraction[Metal Organic Chemical Vapor Deposition  

SciTech Connect

The polarity of laterally epitaxially overgrown (LEO) GaN on Si(111) with an AlN buffer layer grown by MOCVD has been studied by convergent beam electron diffraction (CBED). The LEO GaN was studied by cross-section and plan-view transmission electron microscopy (TEM). The threading dislocation density is less than 10{sup 8} cm{sup {minus}2} and no inversion domains were observed. CBED patterns were obtained at 200 kV for the <1 {bar 1} 00> zone. Simulation was done by many-beam solution with 33 zero-order beams. The comparison of experimental CBED patterns and simulated patterns indicates that the polarity of GaN on Si(111) is Ga face.

Zhao, L.; Marchand, H.; Fini, P.; Denbaars, S.P.; Mishra, U.K.; Speck, J.S.

2000-07-01T23:59:59.000Z

326

Development of a Bulk GaN Growth Technique for Low Defect Density, Large-Area Native Substrates  

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

the Electrochemical Solution the Electrochemical Solution Growth (ESG) Technique for Native GaN Substrates DOE Energy Storage & Power Electronics Research Program 30 September 2008 PI: Karen Waldrip Advanced Power Sources R&D, Dept 2546 PM: Stan Atcitty, John Boyes Sandia National Laboratories, Albuquerque, NM, 87185 Sponsor: Gil Bindewald, DOE Power Electronics & Energy Storage Program Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. Outline * Motivation * Existing GaN Growth Technique - Epitaxial Lateral Overgrowth - Methods for Growing Bulk GaN * Development of the Electrochemical Solution Growth Technique

327

ALS Chemistry Lab  

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

Chemistry Lab Print ALS Chemistry Labs The ALS Chemistry Labs are located in the User Support Building (15-130) and in Building 6 (6-2233)*. These spaces are dedicated for...

328

High-performance GaAs/AlGaAs optical phase modulators for microwave photonic integrated circuits  

SciTech Connect

A high-performance high-speed optical phase modulator for photonic integrated circuit (PIC) use is described. Integration of these optical phase modulators into a real system (compass) is also discussed. The optical phase modulators are based on depletion-edge translation and have experimentally provided optical phase shifts in excess of 60{degrees}/V{center_dot}mm with approximately 4 dB/cm loss while simultaneously demonstrating bandwidths in excess of 10 GHz.

Hietala, V.M.; Kravitz, S.H.; Armendariz, M.G.; Vawter, G.A.; Carson, R.F.

1994-03-01T23:59:59.000Z

329

Investigation of photoexcited parallel conduction in GaAs/AlGaAs heterostructures in the quantum limit  

E-Print Network (OSTI)

', giving rise to the persistent photoconductivity (PPC). As the density of 2-DEG carriers in- creased the systematic shift of the quantum Hall plateaus and corresponding 40 12. 10. T = 75mK Iso= 500 nA 0 b cd c hl 6. Q. 0. 0. 0 1. 0 2. 0 3. 0 4... resistance between 0. 0 and 0. 3 T. 16, 2-DEG carrier density determined from SdH oscillations versus natural logarithm of photon dose at 75 mK. 17, (a) Deviation of the Hall resistance from quantized value at i = 4 plateau versus photon dose; (b...

Kobiela, Pawel Stanislaw

1986-01-01T23:59:59.000Z

330

Mn-doped Ga(As,P) and (Al,Ga)As ferromagnetic semiconductors: Electronic structure calculations  

E-Print Network (OSTI)

ASCR, Na Slovance 2, 182 21 Praha 8, Czech Republic 2Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA 3Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA 4School of Physics... and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom 5Institute of Physics ASCR, Cukrovarnick? 10, 162 53 Praha 6, Czech Republic #1;Received 6 September 2006; published 12 January 2007#2; A remarkable progress towards functional...

Masek, J.; Kudrnovsky, J.; Maca, F.; Sinova, Jairo; MacDonald, A. H.; Campion, R. P.; Gallagher, B. L.; Jungwirth, T.

2007-01-01T23:59:59.000Z

331

Cross-plane Seebeck coefficient of ErAs:InGaAs/InGaAlAs superlattices Gehong Zenga  

E-Print Network (OSTI)

American Institute of Physics. DOI: 10.1063/1.2433751 I. INTRODUCTION Thermoelectric materials can be used conversion devices depends on the thermoelectric figure of merit ZT of a material, which is defined as ZT=S2 thermoelectric material because of i enhancement in the power factor S2 due to the quantum confinement effect,1

Bowers, John

332

Al fraction induced effects on the capacitance characteristics -GaN/AlxGa1-xN IR detectors  

E-Print Network (OSTI)

, Georgia State University, Atlanta, Georgia 30303, USA; bNDP Optronics LLC, Mableton, Georgia 30126, USA; c

Dietz, Nikolaus

333

Negative capacitance in GaN/AlGaN heterojunction dual-band detectors L. E. Byrum,1  

E-Print Network (OSTI)

, USA 2 NDP Optronics LLC, Mableton, Georgia 30126, USA 3 School of Electrical and Computer Engineering

Dietz, Nikolaus

334

Spontaneous coherence, kinetics and pattern formation in cold exciton gases in GaAs/AlGaAs coupled quantum wells  

E-Print Network (OSTI)

Chapter 6 Coherence . . . . . . . . . . . . .way to measure spatial coherence . . . . . . . . . 6.5exciton and optical coherence lengths 6.3.2 Geometrical

Yang, Sen

2009-01-01T23:59:59.000Z

335

Spontaneous coherence, kinetics and pattern formation in cold exciton gases in GaAs/AlGaAs coupled quantum wells  

E-Print Network (OSTI)

2006). [82] S. Yang, A.V. Mintsev, A.T. Hammack, L.V. Butov,L.S. Levitov, A.V. Mintsev, B.D. Simons, A.C. Gossard, D.S.2006). Sen Yang, A.V. Mintsev, A.T. Hammack, L.V. Butov, and

Yang, Sen

2009-01-01T23:59:59.000Z

336

SnO2 functionalized AlGaN/GaN high electron mobility transistor for hydrogen sensing applications  

E-Print Network (OSTI)

for automotive fuel [1] and fuel cells [2] applications. There is great interest in detection of hydrogen sensors for the use in hydrogen-fueled automobiles and with proton- exchange membrane (PEM) and solid oxide fuel cells for monitoring leakage of hydrogen storage equipment and fuel tanks for spacecraft and hydrogen fuel cell

Florida, University of

337

Defect studies in low-temperature-grown GaAs  

SciTech Connect

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

Bliss, D.E.

1992-11-01T23:59:59.000Z

338

Defect studies in low-temperature-grown GaAs  

SciTech Connect

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

Bliss, D.E.

1992-11-01T23:59:59.000Z

339

Energy absorption in Ni-Mn-Ga/ polymer composites  

E-Print Network (OSTI)

In recent years Ni-Mn-Ga has attracted considerable attention as a new kind of actuator material. Off-stoichiometric single crystals of Ni2MnGa can regularly exhibit 6% strain in tetragonal martensites and orthorhombic ...

Feuchtwanger, Jorge

2006-01-01T23:59:59.000Z

340

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

SciTech Connect

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

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

2013-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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341

Study of gain and photoresponse characteristics for back-illuminated separate absorption and multiplication GaN avalanche photodiodes  

SciTech Connect

The gain and photoresponse characteristics have been numerically studied for back-illuminated separate absorption and multiplication (SAM) GaN avalanche photodiodes (APDs). The parameters of fundamental models are calibrated by simultaneously comparing the simulated dark and light current characteristics with the experimental results. Effects of environmental temperatures and device dimensions on gain characteristics have been investigated, and a method to achieve the optimum thickness of charge layer is obtained. The dependence of gain characteristics and breakdown voltage on the doping concentration of the charge layer is also studied in detail to get the optimal charge layer. The bias-dependent spectral responsivity and quantum efficiency are then presented to study the photoresponse mechanisms inside SAM GaN APDs. It is found the responsivity peak red-shifts at first due to the Franz-Keldysh effect and then blue-shifts due to the reach-through effect of the absorption layer. Finally, a new SAM GaN/AlGaN heterojunction APD structure is proposed for optimizing SAM GaN APDs.

Wang, Xiaodong; Pan, Ming; Hou, Liwei; Xie, Wei [No. 50 Research Institute of China Electronics Technology Group Corporation, 200331 Shanghai (China); Hu, Weida, E-mail: wdhu@mail.sitp.ac.cn; Xu, Jintong; Li, Xiangyang; Chen, Xiaoshuang, E-mail: xschen@mail.sitp.ac.cn; Lu, Wei [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 200083 Shanghai (China)

2014-01-07T23:59:59.000Z

342

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

SciTech Connect

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

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

2009-08-17T23:59:59.000Z

343

Hot-carrier cooling in GaAs: Quantum wells versus bulk  

Science Journals Connector (OSTI)

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

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

1993-11-15T23:59:59.000Z

344

Pressure-Induced Transformations of the Low-Cristobalite Phase of GaPO4  

Science Journals Connector (OSTI)

Tsuneyuki et al. predicted a new high pressure phase of silica using a molecular dynamics calculation; this calculation was novel in that it predicted a new crystal structure using only a knowledge of the chemical composition [Nature (London) 339, 209 (1989)]. We report that the low-cristobalite phase of GaPO4 undergoes a pressure-induced transition at 15.9 GPa to this novel phase, which contains tetrahedral and octahedral coordination shells of oxygen atoms around the phosphorus and gallium atoms, respectively. This pressure-induced coordination change in GaPO4 verifies a mechanism proposed for the tetrahedral-to-octahedral coordination change in minerals that occurs in the transition zone between the upper and lower mantle.

Julie L. Robeson; Robert R. Winters; William S. Hammack

1994-09-19T23:59:59.000Z

345

Low Efficiency Droop Green Nano-Pyramid {10 -11} InGaN/GaN Multiple Quantum Well LED  

Science Journals Connector (OSTI)

We report a low efficiency droop 520 nm green nano-pyramid InGaN/GaN multiple quantum well (MQW) LED. MQWs were grown on the semipolar {10 1} nano-pyramid facets. The device physics...

Cheng, Yuh-Jen; Chang, Shih-Pang; Lin, Da-Wei; Kuo, Hao-chung; Xiong, Kang-lin

346

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

Science Journals Connector (OSTI)

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

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

2013-01-01T23:59:59.000Z

347

Seeded growth of AlN bulk crystals in m-and c-orientation , R. Collazo a,, R.F. Dalmau b  

E-Print Network (OSTI)

. Introduction Single crystal AlN is a promising substrate for nitride-based optoelectronic devices exploiting efficiency of optoelectronic devices [8]. Second, AlN and GaN have different valence band structures caused in higher luminous efficiency of deep UV optoelectronic devices. Although the growth of III-nitride thin

Dietz, Nikolaus

348

Nucleation and Growth of GaN on GaAs (001) Substrates  

SciTech Connect

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

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

1999-05-03T23:59:59.000Z

349

Abstract--Utilizing the high index contrast of a deep-etched, non-selectively oxidized AlGaAs/InAlGaAs GRINSCH  

E-Print Network (OSTI)

-etching the SiNx via reactive ion etching (RIE) in a CF4/O2 plasma, and subsequently removed by a Cr etch (both waveguide cladding and core with QW). The SiNx mask is then selectively removed in RIE with CF4/O2

Bowers, John

350

Tiu Ch Chn La D n Khi Phc Sm Vo ngy 21 thng 4 nm 2011, cc y Vin nh Gi Tn Hi  

E-Print Network (OSTI)

con ngi bng cách khôi phc, phc hi môi trng sng, thay th, hoc thu gom mt lng tng ng vi ngun tài nguyên thiên nhiên có cht lng, giá tr sinh thái hoc dân dng tng ng n bù các tài nguyên và dch v b tn hi t s c, nhng vn c chp nhn và hu ích giúp sàng lc mt s lng ln các d án có tim nng. Không mt yu t nào c s dng nh

351

Doping of MBE grown cubic GaN on 3C-SiC (001) by CBr4 ,E. Tschumak1  

E-Print Network (OSTI)

source. The CBr4 beam equivalent pressure was established by a needle valve and was varied between 2x10 has a very low diffusion coefficient [3]. It is also known from p-doping in (Al)GaAs that carbon4 beam equivalent pressure (BEP) was established by a needle valve and was varied between 2x10

As, Donat Josef

352

Lattice-Mismatched GaAs/InGaAs Two-Junction Solar Cells by Direct Wafer Bonding  

SciTech Connect

Direct bonded interconnect between subcells of a lattice-mismatched III-V compound multijunction cell would enable dislocation-free active regions by confining the defect network needed for lattice mismatch accommodation to tunnel junction interfaces, while metamorphic growth inevitably results in less design flexibility and lower material quality than is desirable. The first direct-bond interconnected multijunction solar cell, a two-terminal monolithic GaAs/InGaAs two-junction solar cell, is reported and demonstrates viability of direct wafer bonding for solar cell applications. The tandem cell open-circuit voltage was approximately the sum of the subcell open-circuit voltages. This achievement shows direct bonding enables us to construct lattice-mismatched III-V multijunction solar cells and is extensible to an ultrahigh efficiency InGaP/GaAs/InGaAsP/InGaAs four-junction cell by bonding a GaAs-based lattice-matched InGaP/GaAs subcell and an InP-based lattice-matched InGaAsP/InGaAs subcell. The interfacial resistance experimentally obtained for bonded GaAs/InP smaller than 0.10 Ohm-cm{sup 2} would result in a negligible decrease in overall cell efficiency of {approx}0.02%, under 1-sun illumination.

Tanabe, K.; Aiken, D. J.; Wanlass, M. W.; Morral, A. F.; Atwater, H. A.

2006-01-01T23:59:59.000Z

353

Science DMZ for ALS  

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

ALS Science Engagement Move your data Programs & Workshops Science Requirements Reviews Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ @ UF Science DMZ @ CU...

354

Flüssiger Wasserstoff als Kraftstoff  

Science Journals Connector (OSTI)

Seit mehr als hundert Jahren stellen Kohlenwasserstoffe aus Rohöl fast ausschließlich die Basis für alle im Verkehr verwendeten Kraftstoffe dar. Ein Verkehr ohne Benutzung von Kraftstoffen auf Kohlenwasserstof...

Prof. Dr. Ing. habil. Walter Peschka

1984-01-01T23:59:59.000Z

355

Howes et al. Reply  

E-Print Network (OSTI)

Howes et al. Reply to Comment on "Kinetic Simulations of Magnetized Turbulence in Astrophysical Plasmas" arXiv:0711.4355

G. G. Howes; S. C. Cowley; W. Dorland; G. W. Hammett; E. Quataert; A. A. Schekochihin; T. Tatsuno

2008-12-12T23:59:59.000Z

356

Auger recombination suppression and band alignment in GaAsBi/GaAs heterostructures  

SciTech Connect

Using a combination of experimental and theoretical techniques we present the dependence of the bandgap E{sub g} and the spin orbit splitting energy ?{sub so}, with Bi concentration in GaAsBi/GaAs samples. We find that the concentration at which ?{sub so},> E{sub g} occurs at 9%. Both spectroscopic as well as first device results indicate a type I alignment.

Hild, K.; Batool, Z.; Jin, S. R.; Hossain, N.; Marko, I. P.; Sweeney, S. J. [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Hosea, T. JC. [1 Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, GU2 7XH, UK and also, Ibnu Sina Institute, Universiti Teknologi Malaysia, Johor Bahru, 81310 (Malaysia); Lu, X. [Department of Electrical and Computer Engineering, University of Victoria, Victoria BC, V8W 3P6, Canada and now VarianSemiconductor Equipment Associates, Gloucester, MA 01930 (United States); Tiedje, T. [Department of Electrical and Computer Engineering, University of Victoria, Victoria BC, V8W 3P6 (Canada)

2013-12-04T23:59:59.000Z

357

Recent progress in InGaAsSb/GaSb TPV devices  

SciTech Connect

AstroPower is developing InGaAsSb thermophotovoltaic (TPV) devices. This photovoltaic cell is a two-layer epitaxial InGaAsSb structure formed by liquid-phase epitaxy on a GaSb substrate. The (direct) bandgap of the In{sub 1{minus}x}Ga{sub x}As{sub 1{minus}y}Sb{sub y} alloy is 0.50 to 0.55 eV, depending on its exact alloy composition (x,y); and is closely lattice-matched to the GaSb substrate. The use of the quaternary alloy, as opposed to a ternary alloy--such as, for example InGaAs/InP--permits low bandgap devices optimized for 1,000 to 1,500 C thermal sources with, at the same time, near-exact lattice matching to the GaSb substrate. Lattice matching is important since even a small degree of lattice mismatch degrades device performance and reliability and increases processing complexity. Internal quantum efficiencies as high as 95% have been measured at a wavelength of 2 microns. At 1 micron wavelengths, internal quantum efficiencies of 55% have been observed. The open-circuit voltage at currents of 0.3 A/cm{sup 2} is 0.220 volts and 0.280 V for current densities of 2 A/cm{sup 2}. Fill factors of 56% have been measured at 60 mA/cm{sup 2}. However, as current density increases there is some decrease in fill factor. The results to date show that the GaSb-based quaternary compounds provide a viable and high performance energy conversion solution for thermophotovoltaic systems operating with 1,000 to 1,500 C source temperatures.

Shellenbarger, Z.A.; Mauk, M.G.; DiNetta, L.C. [AstroPower, Inc., Newark, DE (United States); Charache, G.W. [Lockheed Martin Corp., Schenectady, NY (United States)

1996-05-01T23:59:59.000Z

358

Multiband GaNAsP Quaternary Alloys  

SciTech Connect

We have synthesized GaN{sub x}As{sub 1-y}P{sub y} alloys (x {approx} 0.3-1% and y = 0-0.4) using nitrogen N ion implantation into GaAsP epilayers followed by pulsed laser melting and rapid thermal annealing techniques. As predicted by the band anticrossing model, the incorporation of N splits the conduction band (E{sub M}) of the GaAs{sub 1-y}P{sub y} substrate, and strong optical transitions from the valence band to the lower (E{sub -}) and upper (E{sub +}) conduction subbands are observed. The relative strengths of the E{sub -} and E{sub +} transition change as the localized N level E{sub N} emerges from the conduction band forming narrow intermediate band for y > 0.3. The results show that GaN{sub x}As{sub 1-x-y}P{sub y} alloys with y > 0.3 is a three band semiconductor alloy with potential applications for high-efficiency intermediate band solar cells.

Yu, K.M.; Walukiewicz, W.; Ager III, J.W.; Bour, D.; Farshchi,R.; Dubon, O.D.; Li, S.X.; Sharp, I.D.; Haller, E.E.

2005-12-08T23:59:59.000Z

359

Implantation of carbon in GaAs  

SciTech Connect

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

Moll, A.J.

1992-03-01T23:59:59.000Z

360

O?[]O? nuclear ?-decay of ?²Ga  

E-Print Network (OSTI)

The branching ratio for the ?-Decay of ?²Ga to the first excited O? state in ?²Zn has been measured. It is possible to use this branching ratio to test the theoretical method of calculating the [] component of the charge correction term [], which...

Hyman, Bruce Carl

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Nano-scale characterization of GaAsP/GaAs strained superlattice structure by nano-beam electron diffraction  

SciTech Connect

Distribution of lattice strain in a GaAsP/GaAs superlattice with a periodicity of 10?nm thickness, deposited on a 100?nm GaAs basal layer has been measured by nano-beam electron diffraction. The superlattice on the (001) plane of the basal GaAs layer shows a constant lattice strain from the bottom to the top layers, whereas the superlattice on the basal GaAs surface sloped by 16° from the (001) plane shows a variation of the lattice strain and crystal orientation. The difference of the strain distributions was discussed from the viewpoint of average strain. This tilt was explained by an atomistic model.

Jin, Xiuguang [Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Nakahara, Hirotaka [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Saitoh, Koh; Tanaka, Nobuo [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Takeda, Yoshikazu [Nagoya Industrial Science Research Institute, Nagoya 464-0819 (Japan); Aichi Synchrotron Radiation Center, Aichi Science and Technology Foundation, Seto 489-0965 (Japan)

2014-03-17T23:59:59.000Z

362

Science DMZ for ALS  

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

ALS ALS About ESnet Overview ESnet Staff Governance Our Network Case Studies OSCARS Case Studies Science DMZ Case Studies Science DMZ CU Science DMZ Penn State & VTTI Science DMZ NOAA Science DMZ NERSC Science DMZ ALS Multi-facility Workflow LCLS ESnet Strategic Plan ESnet Organizational Chart ESnet History Science Requirements Careers Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Science DMZ for ALS Many beamline scientists at Berkeley Lab's Advanced Light Source (ALS) are or will be experiencing slower network speeds because of instrument upgrades. These new instruments, or more specifically detectors, are

363

SAS Output  

U.S. Energy Information Administration (EIA) Indexed Site

Coal Consumers in the Manufacturing and Coke Sectors, 2012" Coal Consumers in the Manufacturing and Coke Sectors, 2012" "Company Name","Plant Location" "Top Ten Manufacturers" "American Crystal Sugar Co","MN, ND" "Archer Daniels Midland","IA, IL, MN, ND, NE" "Carmeuse Lime Stone Inc","AL, IL, IN, KY, MI, OH, PA, TN, VA, WI" "Cemex Inc","AL, CA, CO, FL, GA, KY, OH, TN, TX" "Dakota Gasification Company","ND" "Eastman Chemical Company","TN" "Georgia-Pacific LLC","AL, GA, OK, VA, WI" "Holcim (US) Inc","AL, CO, MD, MO, MT, OK, SC, TX, UT" "NewPage Corporation","MD, MI, WI" "U S Steel Corporation","AL, IN, MI, MN"

364

U.S. Energy Information Administration | Annual Coal Report 2012  

U.S. Energy Information Administration (EIA) Indexed Site

Coal Consumers in the Manufacturing and Coke Sectors, 2012 Coal Consumers in the Manufacturing and Coke Sectors, 2012 U.S. Energy Information Administration | Annual Coal Report 2012 Table 25. Coal Consumers in the Manufacturing and Coke Sectors, 2012 U.S. Energy Information Administration | Annual Coal Report 2012 Company Name Plant Location Top Ten Manufacturers American Crystal Sugar Co MN, ND Archer Daniels Midland IA, IL, MN, ND, NE Carmeuse Lime Stone Inc AL, IL, IN, KY, MI, OH, PA, TN, VA, WI Cemex Inc AL, CA, CO, FL, GA, KY, OH, TN, TX Dakota Gasification Company ND Eastman Chemical Company TN Georgia-Pacific LLC AL, GA, OK, VA, WI Holcim (US) Inc AL, CO, MD, MO, MT, OK, SC, TX, UT NewPage Corporation MD, MI, WI U S Steel Corporation AL, IN, MI, MN Other Major Manufacturers Ash Grove Cement Co

365

Preparation of Optoelectronic Devices Based on AlN/AlGaN Superlattices M. Holtz,a,b  

E-Print Network (OSTI)

of QDs also suggest strategies for improving the efficiency of optoelectronic devices through vectorial

Holtz, Mark

366

Self-Assembled Monolayers of Alkylphosphonic Acid on GaN Substrates  

Science Journals Connector (OSTI)

In addition to their applications for short-wavelength optoelectronic and high-power electronics, group III nitrides (AlN, GaN, and InN) have been employed as components of chemical and biological sensors for gas and solution samples. ... (27) In the basic solution, ?water decreased quickly to reach a smaller plateau value, probably reflecting the electrostatic repulsion between the deprotonated ODPA and negatively charged gallium oxide surface(46) in addition to the higher solubility of deprotonated ODPA in more basic solution. ... Gallium nitride is a wide band gap semiconductor that demonstrates a unique set of optical and electrical properties as well as aqueous stability and biocompatibility. ...

Takashi Ito; Sarah M. Forman; Chundi Cao; Feng Li; Charles R. Eddy, Jr.; Michael A. Mastro; Ronald T. Holm; Richard L. Henry; Keith L. Hohn; J. H. Edgar

2008-06-04T23:59:59.000Z

367

Thermoelectric properties of lattice-matched AlInN alloy grown by metal organic chemical vapor deposition  

E-Print Network (OSTI)

Seebeck coefficient and resistance measurement system for thermoelectric materials in the thin diskInN alloy on GaN as excellent material candidate for thermoelectric application. © 2010 American Institute-nitride alloys have shown promising results for thermoelectric applications,20­30 in particular for materi- als

Gilchrist, James F.

368

A novel approach for the improvement of open circuit voltage and fill factor of InGaAsSb/GaSb thermophotovoltaic cells  

SciTech Connect

Heterojunction n-Al{sub 0.25}Ga{sub 0.75}As{sub 0.02}Sb{sub 098}/p-In{sub 0.16}Ga{sub 0.84}As{sub 0.04}Sb{sub 0.96} thermophotovoltaic (TPV) cells were grown by molecular-beam epitaxy on n-GaSb-substrates. In the spectral range from 1 {micro}m to 2.1 {micro}m these cells, as well as homojunction n-p-In{sub 0.16}Ga{sub 0.84}As{sub 0.04}Sb{sub 0.96} cells, have demonstrated internal quantum efficiencies exceeding 80%, despite about a 200 meV barrier in the conduction band at the heterointerface. Estimation shows that the thermal emission of the electrons photogenerated in p-region over this barrier can provide high efficiency for hetero-cells if the electron recombination time in p-In{sub 0.16}Ga{sub 0.84}As{sub 0.04}Sb{sub 0.96}is longer than 10 ns. Keeping the same internal efficiency as homojunction cells, hetero-cells provide a unique opportunity to decrease the dark forward current and thereby increase open circuit voltage (V{sub {proportional_to}}) and fill factor at a given illumination level. It is shown that the decrease of the forward current in hetero-cells is due to the lower recombination rate in n-type wider-bandgap space-charge region and to the suppression of the hole component of the forward current. The improvement in V{sub {proportional_to}} reaches 100% at illumination level equivalent to 1 mA/cm{sup 2} and it decreases to 5% at the highest illumination levels (2--3 A/cm{sup 2}), where the electron current component dominates in both the homo- and heterojunction cells. Values of V{sub {proportional_to}} as high as 310 meV have been obtained for a hetero-cell at illumination levels of 3 A/cm{sup 2}. Under this condition, the expected fill factor value is about 72% for a hetero-cell with improved series resistance. The heterojunction concept provides excellent prospects for further reduction of the dark forward current in TPV cells.

Garbuzov, D.Z.; Martinelli, R.U.; Khalfin, V.; Lee, H.; Morris, N.A.; Taylor, G.C.; Connolly, J.C. [Sarnoff Corp., Princeton, NJ (United States); Charache, G.W.; DePoy, D.M. [Lockheed-Martin, Inc., Schenectady, NY (United States)

1997-10-01T23:59:59.000Z

369

ALS Beamlines Directory  

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

ALS Beamlines Directory Print ALS Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone

370

ALS Beamlines Directory  

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

ALS Beamlines Directory Print ALS Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone

371

ALS User Meeting Archives  

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

ALS User Meeting Archives ALS User Meeting Archives Past User Meeting Agendas, Workshops, and Awards Year Agenda Workshops David A. Shirley (Science) Klaus Halbach (Instrumentation) Tim Renner (Service) 2012 2012 User Meeting Agenda 2012 User Meeting Workshops 2012 ALS User Meeting Awards Carl Percival, Dudley Shallcross, Craig Taatjes and David Osborn (Sandia), for making the first direct measurements of the reactions of Criegee intermediates, and showing that their impact on tropospheric chemistry and climate may be substantially greater than previously assumed. 2012 ALS User Meeting Awards Jeff Dickert and Simon Morton of Berkeley Lab's Physical Biosciences Division for the invention and implementation of the Compact Variable Collimator (CVC), which has led to a dramatic increase in productivity of protein crystallography.

372

Hacking als Grenzüberschreitung  

Science Journals Connector (OSTI)

In der Vergangenheit hat es sich als nützlich erwiesen, am Anfang eines Vortrages erst einmal ein paar Worte zu dem Verein zu verlieren, in dessen Vorstand ich mitwirke. Der Chaos Computer Club (CCC) ist viele...

Frank Simon

1994-01-01T23:59:59.000Z

373

ALS Staff Photo  

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

Staff Photo Print On May 14, 2013, members of ALS staff posed for a group photo in front of the dome. A hi-res version can be downloaded here. The last staff photo was taken in...

374

Flachglas Als Baustoff  

Science Journals Connector (OSTI)

Der Werkstoff Glas bezeichnet ein Schmelzprodukt, das in der Natur als erstarrte vulkanische Schmelze vorkommt und dem Mensch bereits vor 5000 Jahren für die Herstellung von Schmuck und Werkstücken diente. Im ...

2007-01-01T23:59:59.000Z

375

0.7-eV GaInAs Junction for a GaInP/GaAs/GaInAs(1eV)/GaInAs(0.7eV) Four-Junction Solar Cell  

SciTech Connect

We discuss recent developments in III-V multijunction solar cells, focusing on adding a fourth junction to the Ga{sub 0.5}In{sub 0.5} P/GaAs/Ga{sub 0.75}In{sub 0.25}As inverted three-junction cell. This cell, grown inverted on GaAs so that the lattice-mismatched Ga{sub 0.75}In{sub 0.25}As third junction is the last one grown, has demonstrated 38% efficiency, and 40% is likely in the near future. To achieve still further gains, a lower-bandgap Ga{sub x}In{sub 1-x}As fourth junction could be added to the three-junction structure for a four-junction cell whose efficiency could exceed 45% under concentration. Here, we present the initial development of the Ga{sub x}In{sub 1-x}As fourth junction. Junctions of various bandgaps ranging from 0.88 to 0.73 eV were grown, in order to study the effect of the different amounts of lattice mismatch. At a bandgap of 0.88 eV, junctions were obtained with very encouraging {approx}80% quantum efficiency, 57% fill factor, and 0.36 eV open-circuit voltage. The device performance degrades with decreasing bandgap (i.e., increasing lattice mismatch). We model the four-junction device efficiency vs. fourth junction bandgap to show that an 0.7-eV fourth-junction bandgap, while optimal if it could be achieved in practice, is not necessary; an 0.9-eV bandgap would still permit significant gains in multijunction cell efficiency while being easier to achieve than the lower-bandgap junction.

Friedman, D. J.; Geisz, J. F.; Norman, A. G.; Wanlass, M. W.; Kurtz, S. R.

2006-01-01T23:59:59.000Z

376

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

E-Print Network (OSTI)

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

377

Graphene in ohmic contact for both n-GaN and p-GaN  

SciTech Connect

The wrinkles of single layer graphene contacted with either n-GaN or p-GaN were found both forming ohmic contacts investigated by conductive atomic force microscopy. The local I–V results show that some of the graphene wrinkles act as high-conductive channels and exhibiting ohmic behaviors compared with the flat regions with Schottky characteristics. We have studied the effects of the graphene wrinkles using density-functional-theory calculations. It is found that the standing and folded wrinkles with zigzag or armchair directions have a tendency to decrease or increase the local work function, respectively, pushing the local Fermi level towards n- or p-type GaN and thus improving the transport properties. These results can benefit recent topical researches and applications for graphene as electrode material integrated in various semiconductor devices.

Zhong, Haijian; Liu, Zhenghui; Shi, Lin; Xu, Gengzhao; Fan, Yingmin; Huang, Zengli [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Wang, Jianfeng; Ren, Guoqiang; Xu, Ke, E-mail: kxu2006@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China)

2014-05-26T23:59:59.000Z

378

Efficiency enhancement of InGaN/GaN solar cells with nanostructures  

SciTech Connect

We demonstrate InGaN/GaN multi-quantum-well solar cells with nanostructures operating at a wavelength of 520?nm. Nanostructures with a periodic nanorod or nanohole array are fabricated by means of modified nanosphere lithography. Under 1 sun air-mass 1.5 global spectrum illumination, a fill factor of 50 and an open circuit voltage of 1.9?V are achieved in spite of very high indium content in InGaN alloys usually causing degradation of crystal quality. Both the nanorod array and the nanohole array significantly improve the performance of solar cells, while a larger enhancement is observed for the nanohole array, where the conversion efficiency is enhanced by 51%.

Bai, J.; Yang, C. C.; Athanasiou, M.; Wang, T. [Department of Electronics and Electrical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

2014-02-03T23:59:59.000Z

379

Optoelectrical characteristics of green light-emitting diodes containing thick InGaN wells with digitally grown InN/GaN  

Science Journals Connector (OSTI)

Compared with conventionally grown thin InGaN wells, thick InGaN wells with digitally grown InN/GaN exhibit superior optical properties. The activation energy (48 meV) of thick InGaN...

Yu, Chun-Ta; Lai, Wei-Chih; Yen, Cheng-Hsiung; Hsu, Hsu-Cheng; Chang, Shoou-Jinn

2014-01-01T23:59:59.000Z

380

In: Proceedings of the 1995 International environmental conference; 1995 May 7-10; Atlanta, GA. Atlanta, GA: TAPPI PRESS: 445-448; 1995.  

E-Print Network (OSTI)

. Atlanta, GA: TAPPI PRESS: 445-448; 1995. ENVIRONMENTALLY SOUND ALTERNATIVES FOR UPGRADING MIXED OFFICE

Abubakr, Said

Note: This page contains sample records for the topic "tn al ga" 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

Surface Science Analysis of GaAs Photocathodes Following Sustained...  

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

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

382

P-type doping of GaN  

SciTech Connect

After implantation of As, As + Be, and As + Ga into GaN and annealing for short durations at temperatures as high as 1500 C, the GaN films remained highly resistive. It was apparent from c-RBS studies that although implantation damage did not create an amorphous layer in the GaN film, annealing at 1500 C did not provide enough energy to completely recover the radiation damage. Disorder recovered significantly after annealing at temperatures up to 1500 C, but not completely. From SIMS analysis, oxygen contamination in the AIN capping layer causes oxygen diffusion into the GaN film above 1400 C. The sapphire substrate (A1203) also decomposed and oxygen penetrated into the backside of the GaN layer above 1400 C. To prevent donor-like oxygen impurities from the capping layer and the substrate from contaminating the GaN film and compensating acceptors, post-implantation annealing should be done at temperatures below 1500 C. Oxygen in the cap could be reduced by growing the AIN cap on the GaN layer after the GaN growth run or by depositing the AIN layer in a ultra high vacuum (UHV) system post-growth to minimize residual oxygen and water contamination. With longer annealing times at 1400 C or at higher temperatures with a higher quality AIN, the implantation drainage may fully recover.

Wong, R.K.

2000-04-10T23:59:59.000Z

383

Spectral-kinetic properties of heterostructures with GaAsSb/InGaAs/GaAs-based quantum wells emitting in the range of 1.0-1.2 {mu}m  

SciTech Connect

The spectral-kinetic properties of heterostructures with GaAs/GaAsSb-based and GaAsSb/InGaAs/GaAs-based quantum wells, emitting in the range of 1.0-1.2 {mu}m are studied with picosecond and nanosecond temporal resolution. Intense photoluminescence in the GaAsSb/InGaAs/GaAs structure, as well as an increase in the photoluminescence wavelength by a factor of 2.5 and a shift of the location of the maximum of the peak ({approx}100 meV) to the longer-wavelength region were observed up to room temperature. It is established that as the molar fraction of Sb and the thickness of the InGaAs layer increase, the energy of the fundamental transition decreases by a factor of 140 meV compared with the GaAsSb/InGaAs/GaAs structure with a lower Sb content and a smaller thickness of the InGaAs layer. At 300 K, the emission wavelength of such a structure was 1.18 {mu}m. In addition, an increase in the thickness of the InGaAs layer led to an increase in the room-temperature photoluminescence intensity by a factor of 60, which is associated with a decrease in the energy of the fundamental state for electrons in the InGaAs layer and, consequently, to larger electron localization and smaller temperature quenching of photoluminescence.

Morozov, S. V., E-mail: more@ipm.sci.-nnov.ru; Kryzhkov, D. I.; Aleshkin, V. Ya. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Zvonkov, B. N.; Vikhrova, O. I. [Nizhni Novgorod State University, Physical-Technical Research Institute (Russian Federation)] [Nizhni Novgorod State University, Physical-Technical Research Institute (Russian Federation)

2013-11-15T23:59:59.000Z

384

100000241,1,1,1,1,20050516,"AL",10610,"Albertville Municipal...  

U.S. Energy Information Administration (EIA) Indexed Site

50,9,24,1,1,511185,"TN",8026,"Newport City of",99 4700013933,1,1,1,1,40469403,"TN",10610,"Oak Ridge City of",99 4700013933,1,2,1,1,2906095,"TN",10620,"Oak Ridge City of",99...

385

Observation of photo darkening in self assembled InGaAs/GaAs quantum dots  

SciTech Connect

Photo darkening was observed in epitaxial InGaAs/GaAs quantum dots (QDs). The photoluminescence (PL) intensity of the QDs showed a non-reversible decrease under continuous laser irradiation. The time constants varied from tens of minutes to several hours, depending on the applied laser power. Based on the spectral evolution, it was concluded that the observed phenomenon should originate from laser induced structural damage and a sustained increase of non-radiative recombination rate in the wetting layer. Additionally, according to the PL decay dynamics at different laser powers, it is argued that there should exist other processes that hinder PL degradation at a high laser power.

Zhang Hongyi; Chen Yonghai; Zhou Xiaolong; Jia Yanan; Ye Xiaoling; Xu Bo; Wang Zhanguo [Key Laboratory of Semiconductor Materials Science and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

2013-05-07T23:59:59.000Z

386

Band gap tuning and optical absorption in type-II InAs/GaSb mid infrared short period superlattices: 14 bands K Dot-Operator p study  

SciTech Connect

The MBE growth of short-period InAs/GaSb type-II superlattice structures, varied around 20.5 A InAs/24 A GaSb were [J. Applied physics, 96, 2580 (2004)] carried out by Haugan et al. These SLs were designed to produce devices with an optimum mid-infrared photoresponse and a sharpest photoresponse cutoff. We have used a realistic and reliable 14-band k.p formalism description of the superlattice electronic band structure to calculate the absorption coefficient in such short-period InAs/GaSb type-II superlattices. The parameters for this formalism are known from fitting to independent experiments for the bulk materials. The band-gap energies are obtained without any fitting parameters, and are in good agreement with experimental data.

AbuEl-Rub, Khaled M. [Department of Applied Physical Sciences, Jordan University of Science and Technology Irbid, 21141 (Jordan)

2012-09-06T23:59:59.000Z

387

Transition to a Virtually Incompressible Oxide Phase at a Shock Pressure of 120 GPa (1.2 Mbar): Gd3Ga5O12  

Science Journals Connector (OSTI)

Cubic, single-crystal, transparent Gd3Ga5O12 has a density of 7.10??g/cm3, a Hugoniot elastic limit of 30 GPa, and undergoes a continuous phase transition from 65 GPa to a quasi-incompressible (QI) phase at 120 GPa. Only diamond has a larger Hugoniot elastic limit. The QI phase of Gd3Ga5O12 is more incompressible than diamond from 170 to 260 GPa. Electrical conductivity measurements indicate the QI phase has a band gap of 3.1 eV. Gd3Ga5O12 can be used to obtain substantially higher pressures and lower temperatures in metallic fluid hydrogen than was achieved previously by shock reverberation between Al2O3 disks.

T. Mashimo, R. Chau, Y. Zhang, T. Kobayoshi, T. Sekine, K. Fukuoka, Y. Syono, M. Kodama, and W. J. Nellis

2006-03-17T23:59:59.000Z

388

Theoretical studies of optical gain tuning by hydrostatic pressure in GaInNAs/GaAs quantum wells  

SciTech Connect

In order to describe theoretically the tuning of the optical gain by hydrostatic pressure in GaInNAs/GaAs quantum wells (QWs), the optical gain calculations within kp approach were developed and applied for N-containing and N-free QWs. The electronic band structure and the optical gain for GaInNAs/GaAs QW were calculated within the 10-band kp model which takes into account the interaction of electron levels in the QW with the nitrogen resonant level in GaInNAs. It has been shown that this interaction increases with the hydrostatic pressure and as a result the optical gain for GaInNAs/GaAs QW decreases by about 40% and 80% for transverse electric and transverse magnetic modes, respectively, for the hydrostatic pressure change from 0 to 40 kilobars. Such an effect is not observed for N-free QWs where the dispersion of electron and hole energies remains unchanged with the hydrostatic pressure. This is due to the fact that the conduction and valence band potentials in GaInAs/GaAs QW scale linearly with the hydrostatic pressure.

Gladysiewicz, M.; Wartak, M. S. [Institute of Physics, Wroclaw University of Technology, 50-370 Wroclaw, Wybrzeze Wyspianskiego 27 (Poland); Department of Physics and Computer Science, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Kudrawiec, R. [Institute of Physics, Wroclaw University of Technology, 50-370 Wroclaw, Wybrzeze Wyspianskiego 27 (Poland)

2014-01-21T23:59:59.000Z

389

ALS in the News  

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

feed-image feed-image Digg: ALSBerkeleyLab Facebook Page: 208064938929 Flickr: advancedlightsource Twitter: ALSBerkeleyLab YouTube: AdvancedLightSource Home About the ALS ALS in the News ALS in the News Roman Seawater Concrete Holds the Secret to Cutting Carbon Emissions Print Tuesday, 04 June 2013 00:00 An international team led by Paulo Monteiro of the Advanced Light Source and UC Berkeley has analyzed samples of Roman concrete from harbor installations that have survived 2,000 years of chemical attack and wave action, "one of the most durable construction materials on the planet," says UC Berkeley's Marie Jackson, a leading member of the team. Says Monteiro, "It's not that modern concrete isn't good, but manufacturing Portland cement accounts for seven percent of the carbon dioxide that industry puts into the air." The carbon footprint of Roman concrete, made from lime, volcanic ash, and seawater, is much smaller.

390

ALS Beamlines Directory  

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

Beamlines Directory Beamlines Directory ALS Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone

391

Partially filled intermediate band of Cr-doped GaN films  

SciTech Connect

We investigated the band structure of sputtered Cr-doped GaN (GaCrN) films using optical absorption, photoelectron yield spectroscopy, and charge transport measurements. It was found that an additional energy band is formed in the intrinsic band gap of GaN upon Cr doping, and that charge carriers in the material move in the inserted band. Prototype solar cells showed enhanced short circuit current and open circuit voltage in the n-GaN/GaCrN/p-GaN structure compared to the GaCrN/p-GaN structure, which validates the proposed concept of an intermediate-band solar cell.

Sonoda, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)

2012-05-14T23:59:59.000Z

392

Phonon-drag thermopower in anisotropic AlAs quantum wells  

SciTech Connect

In the present work we have developed a generalized theory of phonon-drag thermopower ?{sup g} for a highly anisotropic two-dimensional electron gas. For electrons confined in AlAs quantum wells we calculate ?{sup g} as function of temperature. We show that ?{sup g} exhibits a strong anisotropic behavior depending on valley occupancy which can be tuned by well width and strain. Also a great enhancement of ?{sup g} is observed compared to GaAs quantum wells.

Lehmann, Dietmar [Institute of Theoretical Physics, Technische Universität Dresden, D-01062 Dresden (Germany); Tsaousidou, Margarita [Materials Science Department, University of Patras, Patras 26 504 (Greece); Kubakaddi, Shrishail [Department of Physics, Karnatak University, Dharwad-580 003 (India)

2013-12-04T23:59:59.000Z

393

ALS superbend magnet system  

SciTech Connect

The Lawrence Berkeley National Laboratory is preparing to upgrade the Advanced Light Source (ALS) with three superconducting dipoles (Superbends). In this paper we present the final magnet system design which incorporates R&D test results and addresses the ALS operational concerns of alignment, availability, and economy. The design incorporates conduction-cooled Nb-Ti windings and HTS current leads, epoxy-glass suspension straps, and a Gifford-McMahon cryocooler to supply steady state refrigeration. We also present the current status of fabrication and testing.

Zbasnik, J.; Wang, S.T.; Chen, J.Y.; DeVries, G.J.; DeMarco, R.; Fahmie, M.; Geyer, A.; Green, M.A.; Harkins, J.; Henderson, T.; Hinkson, J.; Hoyer, E.H.; Krupnick, J.; Marks, S.; Ottens, F.; Paterson, J.A.; Pipersky, P.; Portmann, G.; Robin, D.A.; Schlueter, R.D.; Steier, C.; Taylor, C.E.; Wahrer, R.

2000-09-15T23:59:59.000Z

394

Electrical properties of pn junctions based on superlattices of AlNAlGa,,In...N  

E-Print Network (OSTI)

, CINVESTAV, Mexico Distrito Federal 07300, Mexico S. Nikishina) and H. Temkin Department of Electrical: 10.1063/1.1603333 Ultraviolet light emitting diodes LEDs with emission wavelengths between 340 and resistivities reflect primarily the in-plane transport in SLs and detailed electrical measurements on mesa

Holtz, Mark

395

Thermoelectric and thermal properties of GaAlAs Peltier-cooled laser diodes  

SciTech Connect

Analyses of heat spreading, temperature distribution, and resultant cooling effects in a monolithically Peltier-cooled laser (MPCL) structure are presented. The analyses were obtained by using Laplace's equation and were made under steady-state conditions, assuming constant thermal conductivity. In this MPCL structure a metal surface layer surrounds a heat-generating p-n laser junction. It is shown that by depositing relatively thick metallic cooling plates a 15% temperature reduction and 25% thermal spreading can be achieved. This heat spreading due to the passive cooling is added to the cooling obtained when the Peltier cooler is operated. Experimental measurements of the effect of Peltier cooling reveal a 6.8 /sup 0/C reduction in junction temperature corresponding to a wavelength shift of as much as 20 A.

Hava, S.; Sequeira, H.B.; Hunsperger, R.G.

1985-09-01T23:59:59.000Z

396

Localized corrosion of GaAs surfaces and formation of porous GaAs  

SciTech Connect

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

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

1995-12-01T23:59:59.000Z

397

Brambilla, et al. Reply  

E-Print Network (OSTI)

Brambilla, et al. Reply: van Megen and Williams (vMW) question our recent claim that dense colloidal hard spheres enter at large volume fraction \\phi a dynamical regime not observed in earlier work and not described by the mode-coupling theory (MCT) of the glass transition.

Giovanni Brambilla; Djamel El Masri; Matteo Pierno; Ludovic Berthier; Luca Cipelletti; George Petekidis; Andrew B. Schofield

2010-08-27T23:59:59.000Z

398

Infrared dielectric properties of Ga1-xAlxAs: Disorder-activated longitudinal-and transverse-acoustic modes  

Science Journals Connector (OSTI)

We present a calculation of the infrared dielectric response of Ga1-xAlxAs. A reference density of vibrational states is calculated in the virtual-crystal approximation with a Born—von Kármán force model. The mass disorder and an additional core-shell internal degree of freedom are then simultaneously accounted for in an extended coherent-potential approximation. Finally, an effective susceptibility is derived; adding the local-field effects gives the dielectric function. The optical spectrum evidences two main optical resonances: one rather GaAs-like, and the other rather AlAs-like. In addition, the model predicts the occurrence of two weak optical bands, which are interpreted as disorder-activated longitudinal and transverse acoustic modes from the Brillouin-zone edge.

R. Bonneville

1984-01-15T23:59:59.000Z

399

Kinetics of GaAs Dissolution in H2O2?NH4OH?H2O Solutions  

Science Journals Connector (OSTI)

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

Christine Bryce; Dimitrios Berk

1996-12-04T23:59:59.000Z

400

CoNiGa High Temperature Shape Memory Alloys  

E-Print Network (OSTI)

commercially successful SMAs such as NiTi and Cu-based alloys. In recent years, the CoNiGa system has emerged as a new ferromagnetic shape memory alloy with some compositions exhibiting high martensitic transformation temperatures which makes CoNiGa a potential...

Dogan, Ebubekir

2011-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

The Essentials for GA Water Planning The Relationship  

E-Print Network (OSTI)

Water Plan and the Alabama-Florida-Georgia Water Sharing Dispute (The failure to agree on the two Management F. Conservation & Reuse a. Programs for Water Use Efficiency b. Consumptive Use & Return Flows GThe Essentials for GA Water Planning The Relationship Between the Proposed GA State Comprehensive

Rosemond, Amy Daum

402

Eine analytische Brennstoffzelle als Alkoholsensor  

Science Journals Connector (OSTI)

Es wird eine analytische Brennstoffzelle zur quantitativen Bestimmung von Alkoholen beschrieben. Als...

H. Huck

403

Smith et al Supporting Information  

E-Print Network (OSTI)

Smith et al 1 Supporting Information for Smith et al. 2006, PLoS Computational Biology 2:e161-hyperpallium apicale; HF-hippocampal formation, and M-mesopallium. #12;Smith et al 2 FigureS2,nolinkswerefoundbetweenelectrodesindifferentbirds,andnolinkswerefoundintothesoundstimulusvariable. CombinedAnalysisofAllBirds'ElectrodesPlusSound #12;Smith et al 3 Analysis of Data from Subsections

Jarvis, Erich D.

404

Structure of a Si(100)2×2-Ga surface  

Science Journals Connector (OSTI)

The 2×2 structure formed on a Ga-adsorbed Si(100) surface is determined using tensor low-energy electron diffraction. I-V curves of the parallel dimer model are in excellent agreement with those of the experiment, indicating that the actual surface has parallel dimer structure. Specific displacements of the topmost two surface layers (the protrusion of the Ga dimer toward the vacuum, the increase of the bond length of the Ga dimer, the stretching of the Si dimer, and the movement of the Si dimer toward the Ga dimer) with the elongation of the Si dimer back bond are observed in the optimized geometry. The Ga-Si bond angle measured from the Si(100) surface plane is recovered with these displacements from that of the ideal geometry where each bond length is assumed to be the sum of Pauling covalent radii. Subsurface layers are also deformed to keep the bond lengths near their bulk values.

H. Sakama; K. Murakami; K. Nishikata; A. Kawazu

1994-11-15T23:59:59.000Z

405

Electronic structure of metallic antiperovskite compound GaCMn3  

Science Journals Connector (OSTI)

We have investigated the electronic structures of antiperovskite GaCMn3 and related Mn compounds SnCMn3, ZnCMn3, and ZnNMn3. In the paramagnetic state of GaCMn3, the Fermi surface nesting feature along the ?R direction is observed, which induces the antiferromagnetic (AFM) spin ordering with the nesting vector Q??R. Calculated susceptibilities confirm the nesting scenario for GaCMn3, and also explain various magnetic structures of other antiperovskite compounds. Through the band folding effect, the AFM phase of GaCMn3 is stabilized. Nearly equal densities of states at the Fermi level in the ferromagnetic and AFM phases of GaCMn3 indicate that two phases are competing in the ground state.

J. H. Shim; S. K. Kwon; B. I. Min

2002-07-10T23:59:59.000Z

406

I I I I OA RIDGE I TIO AL  

Office of Legacy Management (LM)

I I I OA RIDGE I TIO AL aORATOR I I IWARTIN IWARIETTA I I I I I I I I I I I ANAGfD BY ARTIN ARIEllA ENERGY SYSTE S, I C. FOR THE UNITED STATES I OEPARTME T OF E ERGY 9007 ORNlJRASA-93/2 Results of the Radiological Survey at the Fonner Associate Aircraft Tool and Manufacturing Company Site, Fairfield, Ohio (FOHOOl) M. E. Murray R. F. Carrier R. A. Mathis I I I I I Thl8 report has been reproduced d'rectly from the best available copy. I Av labIe to DOE and DOE contractors from the Office of Scientific end Techni- cal Information, P.O. Box 62. Oak Ridge, TN 37831: prices available from (615) 576-8401, FTS 626-8401. Available to the public from the National Technical Intonnatioo Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. I I This report was prepared as an account of work sponsored by an agency of

407

Influence of Electron Doping on Magnetic Order in CeRu2Al10  

SciTech Connect

The effect of electron doping by the substitution of Rh for Ru on unconventional magnetic order in CeRu2Al10 was investigated via neutron powder diffraction. In Ce(Ru1 xRhx)2Al10 with x = 0.05, 0.12, and 0.2, reorientation of the ordered moment from the c-axis as in pure CeRu2Al10 to the a-axis takes place in all samples, while the ordering vector q 0; 1; 0 remains unchanged within this concentration range. The moment reorientation is accompanied by an increase in its size by a factor of 2.4, from = 0.43 B at x = 0 to = 1.06, 1.04, and 1.02 B for x = 0.05, 0.12, and 0.2, respectively. The continuous decrease in the N el temperature T0(TN), despite an abrupt increase in , underlines the strong anisotropy in the exchange interaction in CeRu2Al10 and the fact that this anisotropy is easily suppressed by electron doping. 1.

Kobayashi, Riki [ORNL; Kaneko, Koji [Japan Atomic Energy Agency (JAEA); Saito, Kotaro [Tohoku University, Japan; Mignot, Jean-Michel [Laboratoire Leon Brillouin, France; Andre, Gilles [Laboratoire Leon Brillouin, France; Robert, Julien [Laboratoire Leon Brillouin, France; Wakimoto, Shuichi [Japan Atomic Energy Agency (JAEA); Matsuda, Masaaki [ORNL; Chi, Songxue [ORNL; Haga, Yoshinori [Japan Atomic Energy Agency (JAEA); Matsuda, Tatsuma [Japan Atomic Energy Agency (JAEA); Yamamoto, Etsuji [Japan Atomic Energy Agency (JAEA); Nishioka, Takashi [Kochi University; Tanida, Hiroshi [Hiroshima University, Japan; Sera, Masafumi [Hiroshima University, Japan

2014-01-01T23:59:59.000Z

408

Improved photovoltaic performance of InGaN/GaN solar cells with optimized transparent current spreading layers  

Science Journals Connector (OSTI)

In0.135Ga0.865N/GaN p–i–n solar cells are fabricated and investigated with three types of transparent current spreading layers (TCSLs): Ni/Au layer type (Ni/Au-L), Ni/Au grid type (Ni/Au-G), and ITO layer type (I...

X. M. Cai; Y. Wang; Z. D. Li; X. Q. Lv; J. Y. Zhang; L. Y. Ying…

2013-05-01T23:59:59.000Z

409

Analysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp characteristics  

E-Print Network (OSTI)

injection which we term "thermal impact" , the ther- mal conductivity of the active region is estimatedAnalysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp; published online 21 September 2006 The thermal conductivity of self-organized quantum dot QD active regions

Klotzkin, David

410

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

E-Print Network (OSTI)

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

Lu, Wei

411

ALS Beamlines Directory  

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

Beamlines Directory Print Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone

412

ALS User Meeting Archives  

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

User Meeting Archives Print User Meeting Archives Print Past User Meeting Agendas, Workshops, and Awards Year Agenda Workshops David A. Shirley (Science) Klaus Halbach (Instrumentation) Tim Renner (Service) 2012 2012 User Meeting Agenda 2012 User Meeting Workshops 2012 ALS User Meeting Awards Carl Percival, Dudley Shallcross, Craig Taatjes and David Osborn (Sandia), for making the first direct measurements of the reactions of Criegee intermediates, and showing that their impact on tropospheric chemistry and climate may be substantially greater than previously assumed. 2012 ALS User Meeting Awards Jeff Dickert and Simon Morton of Berkeley Lab's Physical Biosciences Division for the invention and implementation of the Compact Variable Collimator (CVC), which has led to a dramatic increase in productivity of protein crystallography.

413

ALS Beamlines Directory  

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

Beamlines Directory Print Beamlines Directory Print Beamlines, Parameters, Contact Information, and Schedules Download a high-resolution version of the ALS Beamclock. See Beamclock to view the ALS energy-related beamlines beamclock. Beamline Parameters Beamline and endstation technical information is available through the links below. Unless otherwise noted, all beamlines are currently operational. Individual beamline schedules are posted when available. Please contact the responsible beamline scientist for additional schedule information. When calling from off-site, all beamline (BL) phone numbers that begin with a "2" are preceded by 495- (i.e., 495-2014); all others are preceded by 486-. Beamline Number Source Technique/ Group Name Energy Range Beamline Contact Schedule/BL Phone

414

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

SciTech Connect

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

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

2013-11-14T23:59:59.000Z

415

NMR investigation of atomic ordering in AlxGa1xAs thin films C. Degen, M. Tomaselli, and B. H. Meier*  

E-Print Network (OSTI)

-range order with a modulated composition along specific lattice directions has been found.3 The fully ordered by MOVPE in a horizontal Aixtron 200 reactor at a growth temperature of 923 K and a rate of 1.8 m/h using assembly. Two peaks can be observed in both spectra. A comparison with AlAs Alfa Aesar, 99.9% and GaAs semi

Leonardo, Degiorgi

416

Recent Approaches to Modeling Transport of Mercury in Surface Water and Groundwater - Case Study in Upper East Fork Poplar Creek, Oak Ridge, TN - 13349  

SciTech Connect

In this case study, groundwater/surface water modeling was used to determine efficacy of stabilization in place with hydrologic isolation for remediation of mercury contaminated areas in the Upper East Fork Poplar Creek (UEFPC) Watershed in Oak Ridge, TN. The modeling simulates the potential for mercury in soil to contaminate groundwater above industrial use risk standards and to contribute to surface water contamination. The modeling approach is unique in that it couples watershed hydrology with the total mercury transport and provides a tool for analysis of changes in mercury load related to daily precipitation, evaporation, and runoff from storms. The model also allows for simulation of colloidal transport of total mercury in surface water. Previous models for the watershed only simulated average yearly conditions and dissolved concentrations that are not sufficient for predicting mercury flux under variable flow conditions that control colloidal transport of mercury in the watershed. The transport of mercury from groundwater to surface water from mercury sources identified from information in the Oak Ridge Environmental Information System was simulated using a watershed scale model calibrated to match observed daily creek flow, total suspended solids and mercury fluxes. Mercury sources at the former Building 81-10 area, where mercury was previously retorted, were modeled using a telescopic refined mesh with boundary conditions extracted from the watershed model. Modeling on a watershed scale indicated that only source excavation for soils/sediment in the vicinity of UEFPC had any effect on mercury flux in surface water. The simulations showed that colloidal transport contributed 85 percent of the total mercury flux leaving the UEFPC watershed under high flow conditions. Simulation of dissolved mercury transport from liquid elemental mercury and adsorbed sources in soil at former Building 81-10 indicated that dissolved concentrations are orders of magnitude below a target industrial groundwater concentration beneath the source and would not influence concentrations in surface water at Station 17. This analysis addressed only shallow concentrations in soil and the shallow groundwater flow path in soil and unconsolidated sediments to UEFPC. Other mercury sources may occur in bedrock and transport though bedrock to UEFPC may contribute to the mercury flux at Station 17. Generally mercury in the source areas adjacent to the stream and in sediment that is eroding can contribute to the flux of mercury in surface water. Because colloidally adsorbed mercury can be transported in surface water, actions that trap colloids and or hydrologically isolate surface water runoff from source areas would reduce the flux of mercury in surface water. Mercury in soil is highly adsorbed and transport in the groundwater system is very limited under porous media conditions. (authors)

Bostick, Kent; Daniel, Anamary [Professional Project Services, Inc., Bethel Valley Road, Oak Ridge, TN, 37922 (United States)] [Professional Project Services, Inc., Bethel Valley Road, Oak Ridge, TN, 37922 (United States); Tachiev, Georgio [Florida International University, Applied Research Center 10555 W. Flagler St., EC 2100 Miami Florida 33174 (United States)] [Florida International University, Applied Research Center 10555 W. Flagler St., EC 2100 Miami Florida 33174 (United States); Malek-Mohammadi, Siamak [Bradley University, 413A Jobst Hall, Preoria, IL 61625 (United States)] [Bradley University, 413A Jobst Hall, Preoria, IL 61625 (United States)

2013-07-01T23:59:59.000Z

417

Exciton recombination dynamics in InxGa1-xAs/GaAs quantum wells  

Science Journals Connector (OSTI)

Low-temperature decay times ?PL are reported for a series of InxGa1-xAs/GaAs quantum wells. These show a nearly linear increase with increasing thickness (4?Lz?10 nm, x=0.15) but recombination in the widest well (12 nm) is dominated by nonradiative effects. The decay time increases almost linearly with temperature up to 50 K, as expected for free excitons. An increase in ?PL with increasing In composition (0.05?x?0.25, Lz=8 nm) is also observed. Wells with different In compositions exhibit a similar temperature behavior and there is a weak influence of strain on the decay time. Additional peaks in the photoluminescence spectra occur to the low-energy side of the free-exciton peaks. These features, which exhibit longer decay times, are attributed to excitons localized in In-rich islands arising from indium segregation.

Haiping Yu; Christine Roberts; Ray Murray

1995-07-15T23:59:59.000Z

418

Sidewall passivation for InGaN/GaN nanopillar light emitting diodes  

SciTech Connect

We studied the effect of sidewall passivation on InGaN/GaN multiquantum well-based nanopillar light emitting diode (LED) performance. In this research, the effects of varying etch rate, KOH treatment, and sulfur passivation were studied for reducing nanopillar sidewall damage and improving device efficiency. Nanopillars prepared under optimal etching conditions showed higher photoluminescence intensity compared with starting planar epilayers. Furthermore, nanopillar LEDs with and without sulfur passivation were compared through electrical and optical characterization. Suppressed leakage current under reverse bias and four times higher electroluminescence (EL) intensity were observed for passivated nanopillar LEDs compared with unpassivated nanopillar LEDs. The suppressed leakage current and EL intensity enhancement reflect the reduction of non-radiative recombination at the nanopillar sidewalls. In addition, the effect of sulfur passivation was found to be very stable, and further insight into its mechanism was gained through transmission electron microscopy.

Choi, Won Hyuck; Abraham, Michael; Yu, Shih-Ying [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); You, Guanjun; Liu, Jie; Wang, Li; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Mohney, Suzanne E., E-mail: mohney@ems.psu.edu [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

2014-07-07T23:59:59.000Z

419

Amber-green light-emitting diodes using order-disorder Al[subscript x]In[subscript 1?x]P heterostructures  

E-Print Network (OSTI)

We demonstrate amber-green emission from Al[subscript x]In[subscript 1– x]P light-emitting diodes (LEDs) with luminescence peaked at 566?nm and 600?nm. The LEDs are metamorphically grown on GaAs substrates via a graded ...

Christian, Theresa M.

420

Entertainment Technology Center, CMU Post-Graduation Survey Results, Dec 2012, May 2013, and Aug 2013  

E-Print Network (OSTI)

Alumni Contacts 13 ETC dlist email 11 Intern Search/Company Websites 9 Faculty Contacts 8 Interviews Southwest: AZ, NM, OK, TX 1 West: CA, HI, NV 40 Southeast: AL, AR, FL, GA, KY, LA, MS, NC, PR, SC, TN 3

Matsuda, Noboru

Note: This page contains sample records for the topic "tn al ga" 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

Word Pro - Untitled1  

Gasoline and Diesel Fuel Update (EIA)

Annual Energy Review 2011 TX CA FL LA IL OH PA NY GA IN MI NC VA NJ TN WA KY AL MO MN WI SC OK CO IA MD AZ MA MS KS AR OR NE UT CT WV NM NV AK WY ID ND ME MT SD NH HI...

422

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2012 (EIA)

Supply Model Regions Atlantic WA MT WY ID NV UT CO AZ NM TX OK IA KS MO IL IN KY TN MS AL FL GA SC NC WV PA NJ MD DE NY CT ME RI MA NH VA WI MI OH NE SD MN ND AR LA OR CA VT...

423

F-7 U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2012 (EIA)

2014 Regional maps Figure F6. Coal supply regions WA ID OR CA NV UT TX OK AR MO LA MS AL GA FL TN SC NC KY VA WV WY CO SD ND MI MN WI IL IN OH MD PA NJ DE CT MA NH VT NY ME RI...

424

F-5 U.S. Energy Information Administration | Annual Energy Outlook...  

Gasoline and Diesel Fuel Update (EIA)

Supply Model Regions Atlantic WA MT WY ID NV UT CO AZ NM TX OK IA KS MO IL IN KY TN MS AL FL GA SC NC WV PA NJ MD DE NY CT ME RI MA NH VA WI MI OH NE SD MN ND AR LA OR CA VT...

425

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2012 (EIA)

East North Central Mountain AK WA MT WY ID NV UT CO AZ NM TX OK IA KS MO IL IN KY TN MS AL FL GA SC NC WV PA NJ MD DE NY CT VT ME RI MA NH VA WI MI OH NE SD MN ND AR LA OR CA HI...

426

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2012 (EIA)

2013 Regional maps Figure F6. Coal supply regions WA ID OR CA NV UT TX OK AR MO LA MS AL GA FL TN SC NC KY VA WV WY CO SD ND MI MN WI IL IN OH MD PA NJ DE CT MA NH VT NY ME RI...

427

padd map  

U.S. Energy Information Administration (EIA) Indexed Site

for Defense Districts AK HI WA OR CA NV AZ MT WY CO UT ID ND SD NE KS OK MO MN WI MI IL IN OH KY TN IA NM TX AR LA AL MS WV VA NC SC GA FL ME NH VT NY PA NJ MD DE MA CT RI...

428

U.S. Energy Information Administration | Annual Energy Outlook...  

Gasoline and Diesel Fuel Update (EIA)

2012 Regional maps Figure F6. Coal supply regions WA ID OR CA NV UT TX OK AR MO LA MS AL GA FL TN SC NC KY VA WV WY CO SD ND MI MN WI IL IN OH MD PA NJ DE CT MA NH VT NY ME RI...

429

Microsoft Word - figure_99.doc  

Gasoline and Diesel Fuel Update (EIA)

Liquids Production." IN OH TN WV VA KY MD PA NY VT NH MA CT ME RI DE DC NC SC GA FL NJ AL MS LA MO AR TX NM OK CO KS UT AZ WY NE IL IA MN WI ND SD ID MT WA OR NV CA HI AK MI Gulf...

430

U.S. Energy Information Administration | Annual Energy Outlook...  

Gasoline and Diesel Fuel Update (EIA)

AZ OR CA HI V MT WY ID UT CO IV OK IA KS MO IL IN KY TN WI MI OH NE SD MN ND II NM TX MS AL AR LA III NJ CT VT ME RI MA NH FL GA SC NC WV MD DE VA NY PA I PAD District I - East...

431

Gene–Environment Interaction Involving Recently Identified Colorectal Cancer Susceptibility Loci  

Science Journals Connector (OSTI)

...NY, NC, ND, OH, OK, OR, PA, RI, SC, TN, TX, VA, WA, and WY. PLCO: The...lung datasets were accessed from the dbGaP website ( http://www.ncbi.nlm.nih.gov...Brenner H, Buchanan D, et alGenome-wide search for gene-gene interactions in colorectal...

Elizabeth D. Kantor; Carolyn M. Hutter; Jessica Minnier; Sonja I. Berndt; Hermann Brenner; Bette J. Caan; Peter T. Campbell; Christopher S. Carlson; Graham Casey; Andrew T. Chan; Jenny Chang-Claude; Stephen J. Chanock; Michelle Cotterchio; Mengmeng Du; David Duggan; Charles S. Fuchs; Edward L. Giovannucci; Jian Gong; Tabitha A. Harrison; Richard B. Hayes; Brian E. Henderson; Michael Hoffmeister; John L. Hopper; Mark A. Jenkins; Shuo Jiao; Laurence N. Kolonel; Loic Le Marchand; Mathieu Lemire; Jing Ma; Polly A. Newcomb; Heather M. Ochs-Balcom; Bethann M. Pflugeisen; John D. Potter; Anja Rudolph; Robert E. Schoen; Daniela Seminara; Martha L. Slattery; Deanna L. Stelling; Fridtjof Thomas; Mark Thornquist; Cornelia M. Ulrich; Greg S. Warnick; Brent W. Zanke; Ulrike Peters; Li Hsu; and Emily White

2014-09-01T23:59:59.000Z

432

Photovoltaic properties of GaAs:Be nanowire arrays  

SciTech Connect

Arrays of GaAs:Be nanowires are synthesized by molecular beam epitaxy on GaAs(111)B substrates. Prototypes of photovoltaic converters in which the grown nanowire arrays are used as active layers are produced by means of successive photolithography, etching, and metallization processes. Studying the photovoltaic properties of the fabricated structures using a solar radiation simulator demonstrates that the solarenergy conversion efficiency is about 0.1%. The value of the efficiency recalculated with the area occupied by the p-type nanowires on the surface of the n-type GaAs substrate taken into account amounts to 1.1%.

Bouravleuv, A. D.; Beznasyuk, D. V.; Gilstein, E. P. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Tchernycheva, M.; Luna Bugallo, A. De; Rigutti, L. [University Paris Sud 11, Institut d'Electronique Fondamentale UMR CNRS 8622 (France); Yu, L. [CNRS, Laboratoire de Physique des Interfaces et des Couches Minces (LPICM), Ecole Polytechnique (France); Proskuryakov, Yu. [University of Liverpool, Stephenson Institute for Renewable Energy (United Kingdom); Shtrom, I. V.; Timofeeva, M. A. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Samsonenko, Yu. B.; Khrebtov, A. I.; Cirlin, G. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-06-15T23:59:59.000Z

433

Photocurrent Spectroscopy of Single Wurtzite GaAs Nanowires  

SciTech Connect

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

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

2011-12-23T23:59:59.000Z

434

Effects of Ga ion-beam irradiation on monolayer graphene  

SciTech Connect

The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

Wang, Quan; Mao, Wei; Zhang, Yanmin; Shao, Ying; Ren, Naifei [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China)] [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Ge, Daohan [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China) [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

2013-08-12T23:59:59.000Z

435

Electroreflectance study of effects of indium segregation in molecular-beam-epitaxy-grown InGaAs/GaAs  

Science Journals Connector (OSTI)

Electrolyte electroreflectance (EER) experiments were performed on In 0.22 Ga 0.78 As/GaAs single quantum wells grown by the conventional molecular-beam-epitaxy (MBE) shutter operation and also by modified MBE shutter operation intended to form more compositionally abrupt normal and inverted interfaces. The latter included controlled thermal desorption of the surface segregated In at the InGaAs layer surface (flash off) and the deposition of In at the InGaAs/GaAs interface to eliminate compositional broadening (predeposition). The fundamental energy gap and subband transitions were determined experimentally and compared with an accurate calculation of the potential well problem including strain. These results confirmed the segregation of In atoms near the interface. The segregation was maximum in the conventional (normal) MBE sample and least with the modified growth incorporating predeposition and flash off as expected. The segregated atoms are observed to act as dopants and form junctions near the InGaAs/GaAs interface. This study shows that EER can be used as an effective tool for studying the segregation process in MBE growth.

K. Chattopadhyay; J. Aubel; S. Sundaram; J. E. Ehret; R. Kaspi; Keith R. Evans

1997-01-01T23:59:59.000Z

436

The effect of CdS QDs structure on the InGaP/GaAs/Ge triple junction solar cell efficiency  

Science Journals Connector (OSTI)

This work describes optical and electrical characteristics of InGaP/GaAs/Ge triple-junction (T-J) solar cells with CdS quantum dots (QDs) ... quantum dot effectively enhance the overall power conversion efficiency

Chen-Chen Chung; Binh Tinh Tran; Hau-Vei Han; Yen-Teng Ho…

2014-03-01T23:59:59.000Z

437

Improvement of orange ii photobleaching by moderate Ga3+ doping of titania and detrimental effect of structural disorder on Ga overloading  

Science Journals Connector (OSTI)

Highly photoactive Ga3+-doped anatase modification of titania was prepared by homogeneous hydrolysis of aqueous solutions mixture of titanium oxo-sulphate TiOSO4 and gallium(III) nitrate with urea. Incorporation of Ga3+ ...

Václav Štengl, Jilí Henych, Michaela Slušná, Tomáš Matys Grygar, Jana Velická, Martin Kormunda

2014-01-01T23:59:59.000Z

438

Kinetics of indirect photoluminescence in GaAs/AlxGa1?x As double quantum wells in a random potential with a large amplitude  

Science Journals Connector (OSTI)

The kinetics of indirect photoluminescence of GaAs/AlxGa1?x As double quantum wells, characterized by a random potential with a large amplitude (the linewidth of the indirect photoluminescence is ...

L. V. Butov; A. V. Mintsev; A. I. Filin…

1999-05-01T23:59:59.000Z

439

Temperature dependence of photoconductivity in Zn-doped GaN  

SciTech Connect

In agreement with predictions from a model that explained an abrupt thermal quenching of the blue luminescence (BL) band in high-resistivity Zn-doped GaN [Reshchikov et al., Phys. Rev. B 84, 075212 (2011) and Phys. Rev. B 85, 245203 (2012)], we observed the stepwise decrease of photoconductivity in this material with increasing temperature. For the sample studied in this work, the decrease in photoconductivity occurred in two steps at characteristic temperatures T{sub 1} and T{sub 2}. The characteristic temperatures increased with increasing excitation intensity, very similar to the photoluminescence (PL) behavior. The steps in photoconductivity at about 100 K and 200 K are attributed to drop in the concentration of free electrons due to the thermal emission of holes from a shallow acceptor and the Zn{sub Ga} acceptor, respectively, to the valence band and their recombination with electrons via nonradiative centers. This finding supports the model suggested previously and helps to explain other examples of tunable photoconductivity reported in literature.

Reshchikov, Michael A. [Department of Physics, Virginia Commonwealth University, Richmond, VA 23284 (United States)

2014-02-21T23:59:59.000Z

440

Microscopic, electrical and optical studies on InGaN/GaN quantum wells based LED devices  

SciTech Connect

We report here on the micro structural, electronic and optical properties of a GaN-based InGaN/GaN MQW LED grown by the MOVPE method. The present study shows that the threading dislocations present in these LED structures are terminated as V pits at the surface and have an impact on the electrical and optical activity of these devices. It has been pointed that these dislocations were of edge, screw and mixed types. EBIC maps suggest that the electrically active defects are screw and mixed dislocations and behave as nonradiative recombinant centres.

Mutta, Geeta Rani; Venturi, Giulia; Castaldini, Antonio; Cavallini, Anna [Department of Physics and Astronomy, University of Bologna, Viale Carlo Berti Pichat 6/II, 40127 Bologna (Italy); Meneghini, Matteo; Zanoni, Enrico; Meneghesso, Gaudenzio [University of Padova, Department of Information Engineering, via Gradenigo 6/B, Padova 35131 (Italy); Zhu, Dandan; Humphreys, Colin [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom)

2014-02-21T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

Structural and optical properties of GaAs-based heterostructures with Ge and Ge/InGaAs quantum wells  

SciTech Connect

GaAs-based heterostructures with Ge and Ge/InGaAs quantum wells are grown by laser-assisted sputtering. Structural and optical studies of the heterostructures are carried out. A broad photoluminescence line is observed in the wavelength range from 1300 to 1650 nm. The line corresponds to indirect transitions in the momentum space of the Ge quantum wells and to transitions between the In{sub 0.28}Ga{sub 0.72}As and Ge layers, indirect in coordinate space, but direct in momentum space.

Aleshkin, V. Ya.; Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru; Drozdov, M. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Zvonkov, B. N. [Nizhni Novgorod State University, Research Physical Technical Institute (Russian Federation); Kudryavtsev, K. E.; Tonkikh, A. A.; Yablonskiy, A. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Werner, P. [Max Planck Institute of Microstructure Physics (Germany)

2013-05-15T23:59:59.000Z

442

Suppression of electron magnetotunneling between parallel two-dimensional GaAs/InAs electron systems by the correlation interaction  

SciTech Connect

Magnetotunneling between two-dimensional GaAs/InAs electron systems in vertical resonant tunneling GaAs/InAs/AlAs heterostructures is studied. A new-type of singularity in the tunneling density of states, specifically a dip at the Fermi level, is found; this feature is drastically different from that observed previously for the case of tunneling between two-dimensional GaAs tunnel systems in terms of both the kind of functional dependence and the energy and temperature parameters. As before, this effect manifests itself in the suppression of resonant tunneling in a narrow range near zero bias voltage in a high magnetic field parallel to the current direction. Magnetic-field and temperature dependences of the effect's parameters are obtained; these dependences are compared with available theoretical and experimental data. The observed effect can be caused by a high degree of disorder in two-dimensional correlated electron systems as a result of the introduction of structurally imperfect strained InAs layers.

Khanin, Yu. N.; Vdovin, E. E., E-mail: vdov62@yandex.ru [Russian Academy of Sciences, Institute of Microelectronics Technology and High Purity Materials (Russian Federation); Makarovsky, O. [University of Nottingham, School of Physics and Astronomy (United Kingdom)] [University of Nottingham, School of Physics and Astronomy (United Kingdom); Henini, M. [University of Nottingham, School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center (United Kingdom)] [University of Nottingham, School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center (United Kingdom)

2013-09-15T23:59:59.000Z

443

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

SciTech Connect

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

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

2013-12-28T23:59:59.000Z

444

Negative ion photodetachment spectroscopy of the Al3O2 , Al3O3 , Al4Ox , Al5Ox (x = 35), Al6O5 , and Al7O5 clusters  

E-Print Network (OSTI)

Negative ion photodetachment spectroscopy of the Al3O2 , Al3O3 , Al4Ox , Al5Ox (x = 3­5), Al6O5 , and Al7O5 clusters Giovanni Meloni, Michael J. Ferguson and Daniel M. Neumark Department of Chemistry as an Advance Article on the web 9th September 2003 The Al3O2 , Al3O3 , Al4Ox , Al5Ox (x ¼ 3­5), Al6O5 , and Al7

Neumark, Daniel M.

445

Polarization charges and polarization-induced barriers in AlxGa1xNGaN and InyGa1yNGaN heterostructures  

E-Print Network (OSTI)

N�GaN heterostructures L. Jia,a) E. T. Yu, D. Keogh, and P. M. Asbeck Department of Electrical and Computer EngineeringGa1 yN surrounded by n-GaN, capacitance­ voltage profiling studies combined with elementary will most likely require further improvements in p-type GaN conduc- tivity and fabrication of low-resistance

Yu, Edward T.

446

FUPWG Meeting Agenda - Atlanta, GA | Department of Energy  

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

Atlanta, GA Atlanta, GA FUPWG Meeting Agenda - Atlanta, GA October 7, 2013 - 3:16pm Addthis Energy on My Mind / FUPWG / Atlanta, GA / May 3-4, 2006 Hosted by: AGL Resources Logo May 3-4, 2006 Hosted by AGL Resources Atlanta, Georgia Tuesday, May 2, 2006 5:00 - 6:30 Steering Committee meeting in the Danube Tigris Room 6:30 until... Networking dinner at the Marriott Wednesday, May 3, 2006 7:45 am Registration/Continental Breakfast 8:30 - 8:45 Welcome from Suzanne Sitherwood, SVP, Southern Operations, President, Atlanta Gas Light, Chattanooga Gas & Florida City Gas 8:45 - 9:00 FEMP Southeast Regional Office Welcome Traci Leath, FEMP 9:00 - 9:45 Washington Update David McAndrew, FEMP 9:45 - 10:15 Break - Networking 10:15 - 11:20 Navy Technical Program Update Paul Kistler, U.S. Navy

447

Elba Island, GA Natural Gas Liquefied Natural Gas Imports from...  

U.S. Energy Information Administration (EIA) Indexed Site

Egypt (Million Cubic Feet) Elba Island, GA Natural Gas Liquefied Natural Gas Imports from Egypt (Million Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 5,780...

448

Lattice vibrations of pure and doped GaSe  

SciTech Connect

The Bridgman method is used to grow especially undoped and doped single crystals of GaSe. Composition and impurity content of the grown crystals were determined using X-ray fluorescence (XRF) method. X-ray diffraction, Raman scattering, photoluminescence (PL), and IR transmission measurements were performed at room temperature. The long wavelength lattice vibrations of four modifications of GaSe were described in the framework of modified one-layer linear-chain model which also takes into consideration the interaction of the selenium (Se) atom with the second nearest neighbor gallium (Ga) atom in the same layer. The existence of an eight-layer modification of GaSe is suggested and the vibrational frequencies of this modification are explained in the framework of a lattice dynamical model considered in the present work. Frequencies and the type of vibrations (gap, local, or resonance) for the impurity atoms were calculated and compared with the experimental results.

Allakhverdiev, K. [Materials Institute, Marmara Research Center, TUBITAK, Gebze/Kocaeli 41470 (Turkey) and Institute of Physics, Azerbaijan National Academy of Sciences, Baku AZ1143 (Azerbaijan)]. E-mail: kerim.allahverdi@mam.gov.tr; Baykara, T. [Materials Institute, Marmara Research Center, TUBITAK, Gebze/Kocaeli 41470 (Turkey); Ellialtioglu, S. [Department of Physics, Middle East Technical University, Ankara 06531 (Turkey); Hashimzade, F. [Institute of Physics, Azerbaijan National Academy of Sciences, Baku AZ1143 (Azerbaijan); Huseinova, D. [Institute of Physics, Azerbaijan National Academy of Sciences, Baku AZ1143 (Azerbaijan); Kawamura, K. [Institute of Materials Science, University of Tsukuba 305-8573 (Japan); Kaya, A.A. [Materials Institute, Marmara Research Center, TUBITAK, Gebze/Kocaeli 41470 (Turkey); Kulibekov, A.M. [Department of Physics, Mugla University, Mugla 48000 (Turkey); Onari, S. [Institute of Materials Science, University of Tsukuba 305-8573 (Japan)

2006-04-13T23:59:59.000Z

449

GaAs solar cells close to the thermodynamic limit  

Science Journals Connector (OSTI)

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

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

450

Transverse acoustic actuation of Ni-Mn-Ga single crystals  

E-Print Network (OSTI)

Two methods for the transverse acoustic actuation of {110}-cut Ni-Mn-Ga single crystals are discussed. In this actuation mode, crystals are used that have the {110}- type twinning planes parallel to the base of the crystal. ...

Simon, Jesse Matthew

2007-01-01T23:59:59.000Z

451

Modeling of InGaN/Si tandem solar cells  

Science Journals Connector (OSTI)

We investigate theoretically the characteristics of monolithic InGaN/Si two-junction series-connected solar cells using the air mass 1.5 global irradiance spectrum. The addition of an InGaN junction is found to produce significant increases in the energy conversion efficiency of the solar cell over that of one-junction Si cells. Even when Si is not of high quality such two-junction cells could achieve efficiencies high enough to be practically feasible. We also show that further though smaller improvements of the efficiency can be achieved by adding another junction to form an InGaN/InGaN/Si three-junction cell.

L. Hsu; W. Walukiewicz

2008-01-01T23:59:59.000Z

452

Exciton front propagation in photoexcited GaAs quantum wells  

E-Print Network (OSTI)

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

Yang, Sen

453

Evaporation-based Ge/.sup.68 Ga Separation  

DOE Patents (OSTI)

Micro concentrations of .sup.68 Ga in secular equilibrium with .sup.68 Ge in strong aqueous HCl solution may readily be separated in ionic form from the .sup.68 Ge for biomedical use by evaporating the solution to dryness and then leaching the .sup.68 Ga from the container walls with dilute aqueous solutions of HCl or NaCl. The chloro-germanide produced during the evaporation may be quantitatively recovered to be used again as a source of .sup.68 Ga. If the solution is distilled to remove any oxidizing agents which may be present as impurities, the separation factor may easily exceed 10.sup.5. The separation is easily completed and the .sup.68 Ga made available in ionic form in 30 minutes or less.

Mirzadeh, Saed (Albuquerque, NM); Whipple, Richard E. (Los Alamos, NM); Grant, Patrick M. (Los Alamos, NM); O'Brien, Jr., Harold A. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

454

Organometallic Vapor Phase Epitaxy of n-GaSb and n-GaInAsSb for Low Resistance Ohmic Contacts  

SciTech Connect

A comparison of n-GaSb and n-GaInAsSb epilayers for ohmic contacts in GaSb-based devices is studied. The epilayers were grown by organometallic vapor phase epitaxy and doped with Te. At similar electron concentrations, the atomic Te concentration, as determined by secondary ion mass spectroscopy, is more than 2 times higher in n-GaSb compared to n-GaInAsSb. In addition, the electron mobility is lower in n-GaSb than n-GaInAsSb at similar electron concentrations. The electron concentration saturates at about 1.3 x 10{sup 18} cm{sup -3} for n-GaSb, but linearly increases for n-GaInAsSb. Pd/Ge/Au/Pt/Au metallization was studied for ohmic contacts. A specific contact resistivity of 1 x 10{sup -5}{Omega}-cm{sup 2} for n-GaSb was measured. The specific contact resistivity can be greatly improved by contacting n-GaInAsSb, and a significantly lower specific contact resistivity of 2 x 10{sup -6} {Omega}-cm{sup 2} for n-GaInAsSb was measured.

C.A. Wang; D.A. Shiau; R.K. Huang; C.T. Harris; M.K. Connors

2003-07-10T23:59:59.000Z

455

2013 ALS User Meeting Highlights  

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

2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights Print This year's ALS User Meeting launched with a welcome from Users' Executive Committee Chair Corie Ralston and LBNL Director Paul Alivisatos. ALS Director Roger Falcone followed with a "state of the ALS" presentation that began with a reminder of the ALS mission, which he noted remains true even in the midst of a government shutdown: "Supporting users in doing outstanding science in a safe environment." Falcone gave the 414 meeting attendees an update on the ALS beamlines, which included good news about increased user numbers thanks to the new RAPIDD access system, enhanced robotics, and remote capabilities. Falcone reflected that ALS metrics continue to represent our highly productive users-the number of journal articles and papers per user that come from ALS research have continued to grow in the past year. Looking forward, Falcone touched on how a proposed ALS upgrade to a diffraction-limited light source would increase scientific capabilities.

456

2013 ALS User Meeting Highlights  

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

2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights 2013 ALS User Meeting Highlights Print Thursday, 24 October 2013 09:06 This year's ALS User Meeting launched with a welcome from Users' Executive Committee Chair Corie Ralston and LBNL Director Paul Alivisatos. ALS Director Roger Falcone followed with a "state of the ALS" presentation that began with a reminder of the ALS mission, which he noted remains true even in the midst of a government shutdown: "Supporting users in doing outstanding science in a safe environment." Falcone gave the 414 meeting attendees an update on the ALS beamlines, which included good news about increased user numbers thanks to the new RAPIDD access system, enhanced robotics, and remote capabilities. Falcone reflected that ALS metrics continue to represent our highly productive users-the number of journal articles and papers per user that come from ALS research have continued to grow in the past year. Looking forward, Falcone touched on how a proposed ALS upgrade to a diffraction-limited light source would increase scientific capabilities.

457

GAMETOPHYTIC SELF-INCOMPATIBILITY (Newbigin et al., 1993; Matton et al., 1994; Dodds et al., 1997)  

E-Print Network (OSTI)

GAMETOPHYTIC SELF-INCOMPATIBILITY (Newbigin et al., 1993; Matton et al., 1994; Dodds et al., 1997, but expressed at high levels in the style. d. There are high levels of this gene product in self-incompatible species, whereas very low levels in self-compatible species. f. Generalized features: #12;Self-incompatibility

Bhattacharyya, Madan Kumar

458

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

SciTech Connect

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

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

2014-02-01T23:59:59.000Z

459

Electronic properties of the Ga vacancy in GaP(110) surfaces determined by scanning tunneling microscopy  

Science Journals Connector (OSTI)

The electronic properties of uncharged Ga monovacancies in GaP(110) surfaces are determined from voltage-dependent scanning tunneling microscopy images. The signatures of localized defect states in the band gap are analyzed and their spatial location is determined. Empty and occupied defect states exist. Depressed dangling bonds in the occupied-state images indicate an inward relaxation of the neighboring P atoms. The results agree with recent theoretical work.

Ph. Ebert and K. Urban

1998-07-15T23:59:59.000Z

460

Microscopic identification of the compensation mechanisms in Si-doped GaAs  

Science Journals Connector (OSTI)

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

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

1996-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" 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

ENVIRONMENT AL REVI  

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

ENVIRONMENT ENVIRONMENT AL REVI EW for CATEG ORI CAL EXCLUS ION DETE RMINATION Rocky Mo unta in Region, Weste rn A rea Power Administra tion Stru cture Replace ment Fla min g Go rge-Vern a l No.3 138-kV tra nsmiss ion lin e (Struct ure No. 25/6) Spr ing 201 2 A. Ilricf J)cscription of Proposal: Western Area Power Adm inistration (Western) proposes to replace Structure No. 25/6 on the Flaming Gorge-Vernal No.3 138-kV transmission line. The structure is located on Bureau of Land Management lands in Uintah County. Utah (Township 3S, Range 22E, Section 7; Donkey Flat 7.5' USGS quadrangle). Work consists of removal and in-kind replacement of the wood H-frame structure and anchors utilizing rubber tired vehicles. crane, bucket truck, pole trucks/trailers, auger rig. and pick-up trucks. All work will be conducted on Western's existing

462

Catalytic Effect of Ti for Hydrogen Cycling in NaAlH4  

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

Effect of Ti for Effect of Ti for Hydrogen Cycling in NaAlH 4 Mei-Yin Chou School of Physics Georgia Institute of Technology (DE-FG02-05ER46229) Acknowledgment: Yan Wang, Roland Stumpf Why is NaAlH 4 interesting? A viable candidate for hydrogen-storage material: High theoretical weight-percent hydrogen content of 5.55% and low cost But (before 1997) Dehydrogenation occurs at high temperature; rehydrogenation is difficult. Bogdanovic and Schwickardi, 1997 Hydrogen can be reversibly absorbed and desorbed from NaAlH 4 under moderate conditions by the addition of catalysts (compounds containing Ti, Zr, etc.) High Hydrogen Contents in Complex Hydrides Hydride wt% Hydride wt% Be(BH 4 ) 2 20.8 Mg(AlH 4 ) 2 9.3 LiBH 4 18.2 Ca(AlH 4 ) 2 7.9 Mg(BH 4 ) 2 14.9 KBH 4 7.5 Ca(BH 4 ) 2 11.6 NaAlH 4 7.5 NaBH4 10.7 Ga(AlH

463

Solutions of the k?p Hamiltonian in confined systems with a highly nonparabolic dispersion and consequences for AlAs quantum wells  

Science Journals Connector (OSTI)

We present two methods to deal with quantum confinement in systems with a camel’s back dispersion. The two-band Hamiltonian for AlAs X states is solved both by analytical and transfer-matrix methods. The latter offers a general yet relatively simple and flexible way to deal with all types of potential profile. We calculate energy spectra and wave functions for single GaAs/AlAs/GaAs quantum wells and discuss the implications of our results on ?-XZ mixing. We also determine the Landau level fan for AlAs systems with the magnetic field perpendicular to the camel’s back axis. In both cases, we find the confined energies and wave functions to be greatly affected by the k?p interaction. We also show that the well-known type I–type II transition for GaAs/AlAs superlattices is modeled correctly by taking the k?p interaction into account, and that previous effective mass treatments are not reliable. In addition, the crossover from XZ to XX,Y ground states in AlAs confined systems is reevaluated.

Laura E. Bremme and P. C. Klipstein

2002-12-20T23:59:59.000Z

464

Energieversorgung als Dienstleistung—Elektrizitätswirtschaft  

Science Journals Connector (OSTI)

Im Herbst 1988 legte die VDEW ihren Hitgliedsunternehmen das Positionspapier “Die Stromversorger als Dienstleistungspartner” vor und machte es zugleich einer interessierten Öffentlichkeit bekannt. Das Position...

K. Bechthold

1991-01-01T23:59:59.000Z

465

Energieversorgung als Dienstleistung—Mineralölwirtschaft  

Science Journals Connector (OSTI)

Meine Damen, meine Herren, Energieversorgung als Dienstleistung, dieses Thema beherrscht die Energiediskussion seit einiger Zeit. Der Begriff ist etwas schillernd, seine genaue Eingrenzung schwierig, aber er k...

P. Schillmöller

1991-01-01T23:59:59.000Z

466

Transiträume als Orte des Konsums.  

E-Print Network (OSTI)

??Insbesondere seit den 1990er Jahren ist international eine wachsende Bedeutung der Transiträume Tankstelle, Flughafen und Bahnhof als Einzelhandels- und Dienstleistungsstandorte zu beobachten. Vielfältige Gründe sowohl… (more)

Korn, Juliane

2006-01-01T23:59:59.000Z

467

Lasing characteristics of GaSb/GaAs self-assembled quantum dots embedded in an InGaAs quantum well  

E-Print Network (OSTI)

Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico, New Mexico 87545 Received 26 February 2007; accepted 1 June 2007; published online 28 June 2007 intriguing optoelectronic device possibilities on GaAs substrates including lasers, detectors, or solar cells

Jalali. Bahram

468

Growth of Core?Shell Ga?GaN Nanostructures via a Conventional Reflux Method and the Formation of Hollow GaN Spheres  

Science Journals Connector (OSTI)

Gallium nitride (GaN) is an important III?V semiconductor with a wide direct band gap of ?3.4 eV. ... LiHMDS exhibits good solubility in TOA. ... The products were collected by centrifugation twice at 7000 rpm for 2 min in hexane, isopropanol, ethanol, and then deionized water. ...

Tz-Jun Kuo; Chi-Liang Kuo; Chun-Hong Kuo; Michael H. Huang

2009-02-05T23:59:59.000Z

469

Maskless lateral epitaxial overgrowth of GaN on sapphire  

SciTech Connect

The authors demonstrate a technique of lateral epitaxial overgrowth (LEO) of GaN, termed maskless LEO, in which no mask is deposited prior to LEO regrowth. Instead, a bulk (> 2 {micro}m) GaN layer on sapphire is selectively dry etched, leaving {approximately} 5 {micro}m-wide stripe mesas oriented in the <10{bar 1}0>{sub GaN} direction, with a 20 {micro}m period. These stripes serve as seeds for LEO GaN growth, which proceeds from the tops of the stripes and expands laterally, resulting in a T, or overhang, morphology. As for LEO over an SiO{sub 2} mask, significant defect reduction (from {approximately} 10{sup 9} cm{sup {minus}2} to {approximately} 10{sup 6} cm{sup {minus}2}) is observed in cross-sectional transmission electron microscopy (TEM). Atomic force microscopy of the top surface of the LEO GaN reveals that no threading dislocations with screw component terminate at the surfaces of laterally overgrown regions. X-ray diffraction measurements reveal that the wings exhibit a crystallographic tilt away from the seed regions in an azimuth perpendicular to the stripe direction; the tilt angle ({approximately} 0.4--0.5{degree}) is relatively independent of growth temperature and wing aspect ratio.

Fini, P.; Marchand, H.; Ibbetson, J.P.; Moran, B.; Zhao, L.; Denbaars, S.P.; Speck, J.S.; Mishra, U.K.

1999-07-01T23:59:59.000Z

470

Metal contacts on ZnSe and GaN  

SciTech Connect

Recently, considerable interest has been focused on the development of blue light emitting materials and devices. The focus has been on GaN and ZnSe, direct band gap semiconductors with bands gaps of 3.4 and 2.6 eV, respectively. To have efficient, reliable devices it is necessary to have thermally and electrically stable Ohmic contacts. This requires knowledge of the metal-semiconductor reaction behavior. To date few studies have investigated this behavior. Much information has accumulated over the years on the behavior of metals on Si and GaAs. This thesis provides new knowledge for the more ionic wide band gap semiconductors. The initial reaction temperatures, first phases formed, and phase stability of Pt, Pd, and Ni on both semiconductors were investigated. The reactions of these metals on ZnSe and GaN are discussed in detail and correlated with predicted behavior. In addition, comparisons are made between these highly ionic semiconductors and Si and GaAs. The trends observed here should also be applicable to other II-VI and III-Nitride semiconductor systems, while the information on phase formation and stability should be useful in the development of contacts for ZnSe and GaN devices.

Duxstad, K.J. [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering; [Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1997-05-01T23:59:59.000Z

471

Site-controlled fabrication of Ga nanodroplets by focused ion beam  

SciTech Connect

Ga droplets are created by focused ion beam irradiation of GaAs surface. We report that ordered Ga droplets can be formed on the GaAs surface without any implantation damage. The droplets are characterized with bigger sizes than those droplets formed on damaged area. These aligned Ga droplets are formed via the migration of Ga atoms from ion irradiation area to the edge of undamaged GaAs surface and further nucleation into droplets. The morphological evolution and size distribution of these nanodroplets are investigated systematically with different beam irradiation time and incident angles. Based on this method, well positioned Ga nanodroplets, such as chains, are achieved by using focus ion beam patterning. The controllable assembly of droplets on undamaged semiconductor surface can be used to fabricate templates, to fabricate quantum structures and quantum devices by droplet epitaxy technique.

Xu, Xingliang; Wang, Zhiming M., E-mail: zhmwang@gmail.com [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China); Wu, Jiang; Li, Handong; Zhou, Zhihua [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Wang, Xiaodong [Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China)

2014-03-31T23:59:59.000Z

472

Atomic-Level Study of Melting Behavior of GaN Nanotubes. | EMSL  

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

Melting Behavior of GaN Nanotubes. Atomic-Level Study of Melting Behavior of GaN Nanotubes. Abstract: Molecular dynamics simulations with a Stillinger-Weber potential have been...

473

Device-level thermal analysis of GaN-based electronics  

E-Print Network (OSTI)

Gallium nitride (GaN)-based microelectronics are one of the most exciting semiconductor technologies for high power density and high frequency electronics. The excellent electrical properties of GaN and its related alloys ...

Bagnall, Kevin Robert

2013-01-01T23:59:59.000Z

474

Realization of high-quality HfO{sub 2} on In{sub 0.53}Ga{sub 0.47}As by in-situ atomic-layer-deposition  

SciTech Connect

High {kappa} dielectric of HfAlO/HfO{sub 2} was an in-situ atomic-layer-deposited directly on molecular beam epitaxy grown In{sub 0.53}Ga{sub 0.47}As surface without using pre-treatments or interfacial passivation layers, where HfAlO (HfO{sub 2}:Al{sub 2}O{sub 3} {approx} 4:1) with high re-crystallization temperature was employed as the top oxide layer. The HfAlO ({approx}4.5 nm)/HfO{sub 2} (0.8 nm)/In{sub 0.53}Ga{sub 0.47}As metal oxide semiconductor capacitors have exhibited an oxide/In{sub 0.53}Ga{sub 0.47}As interface free of arsenic-related defective bonding, thermodynamic stability at 800 deg. C, and low leakage current densities of <10{sup -7} A/cm{sup 2} at {+-}1 MV/cm. The interfacial trap density (D{sub it}) spectra in absence of mid-gap peaks were obtained by temperature-dependent capacitance and conductance with D{sub it}'s of 2-3 x 10{sup 12} eV{sup -1} cm{sup -2} below and 6-12 x 10{sup 11} eV{sup -1} cm{sup -2} above the mid-gap of In{sub 0.53}Ga{sub 0.47}As, respectively. An equivalent oxide thickness of less than 1 nm has been achieved by reducing the HfAlO thickness to {approx}2.7 nm with the same initial HfO{sub 2} thickness of {approx}0.8 nm.

Lin, T. D.; Hong, M. [Graduate Institute of Applied Physics and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Y. H. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lin, C. A.; Huang, M. L.; Lee, W. C. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Kwo, J. [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

2012-04-23T23:59:59.000Z

475

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

Science Journals Connector (OSTI)

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

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

1997-02-15T23:59:59.000Z

476

Measurement of the transmission magnetic circular dichroism of Ga{sub 1?x}Mn{sub x}As epilayers using a built-in p-i-n photodiode  

SciTech Connect

By constructing a GaMnAs epilayer/semi-insulating In{sub 0.2}Ga{sub 0.8}As/(001) n{sup +}-GaAs substrate layer structure as a built-in p-i-n photodiode, we developed a scheme for on-chip measurements of transmission magnetic circular dichroism (T-MCD). Both the hysteresis loops in the magnetic field sweeps and the wavelength scans at saturated magnetic fields measured using the new T-MCD scheme, illustrated the same features as those previously measured on the freestanding GaMnAs thin films by conventional T-MCD. Because a large group of epitaxially grown magnetic film/semiconductor heterostructures, such as Fe, NiFe, CoFeAl, and MnGa films on semiconductor substrates, are becoming important new building blocks for semiconductor-based spin field-effect transistor, perpendicular magnetic tunnel junction (p-MTJ) and lateral MTJ devices, the new T-MCD scheme can be applied to tests of their magnetic properties by forming either p-i-n or Schottky photodiodes.

He, Z. X.; Zheng, H. Z., E-mail: hzzheng@red.semi.ac.cn; Wang, H. L.; Zhao, J. H. [State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083 (China)

2014-02-28T23:59:59.000Z

477

THERMAL STUDY OF A GaN-BASED HEMT A Dissertation  

E-Print Network (OSTI)

of gallium-nitride (GaN) high-electron-mobility transistors (HEMTs) under bias conditions. An experimental

Sen, Mihir

478

Substrate-dependent wetting layer formation during GaN growth: Impact on the morphology of the films  

SciTech Connect

We have compared epitaxial growth of GaN films on 6H-SiC(0001)-({radical}(3)x{radical}(3))R30 deg. -Ga and on (0001)-sapphire. Predeposited Ga layers were nitrided by ion beam assisted molecular beam epitaxy. Whereas on SiC the initially deposited Ga covers the substrate surface completely, on sapphire only Ga droplets are present. The different distribution of the predeposited Ga affects the morphology of GaN significantly. Scanning electron microscopy and atomic force microscopy analysis of the grown films show that the complete wetting of the SiC substrate with Ga enhances finally the size and the flatness of GaN terraces and thus the quality of the film. X-ray photoelectron spectroscopy measurements reveal that metallic Ga resides also on top of the GaN films during the growth.

Sidorenko, A.; Peisert, H.; Neumann, H.; Chasse, T. [Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany); Leibniz-Institut fuer Oberflaechenmodifizierung e.V. Permoserstrasse 15, D-04318 Leipzig (Germany); Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany)

2007-08-15T23:59:59.000Z

479

Spin dependent transport properties of Mn-Ga/MgO/Mn-Ga magnetic tunnel junctions with metal(Mg, Co, Cr) insertion layer  

SciTech Connect

We report a first principles theoretical investigation of spin polarized quantum transport in Mn{sub 2}Ga/MgO/Mn{sub 2}Ga and Mn{sub 3}Ga/MgO/Mn{sub 3}Ga magnetic tunneling junctions (MTJs) with the consideration of metal(Mg, Co, Cr) insertion layer effect. By changing the concentration of Mn, our calculation shows a considerable disparity in transport properties: A tunneling magnetoresistance (TMR) ratio of 852% was obtained for Mn{sub 2}Ga-based MTJs, however, only a 5% TMR ratio for Mn{sub 3}Ga-based MTJs. In addition, the influence of insertion layer has been considered in our calculation. We found the Co insertion layer can increase the TMR of Mn{sub 2}Ga-based MTJ to 904%; however, the Cr insertion layer can decrease the TMR by 668%; A negative TMR ratio can be obtained with Mg insertion layer. Our work gives a comprehensive understanding of the influence of different insertion layer in Mn-Ga based MTJs. It is proved that, due to the transmission can be modulated by the interfacial electronic structure of insertion, the magnetoresistance ratio of Mn{sub 2}Ga/MgO/Mn{sub 2}Ga MTJ can be improved by inserting Co layer.

Liang, S. H.; Tao, L. L.; Liu, D. P., E-mail: dpliu@iphy.ac.cn; Han, X. F., E-mail: xfhan@iphy.ac.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Lu, Y. [Institut Jean Lamour, UMR 7198, CNRS-Nancy Université, BP 239, 54506 Vandoeuvre (France)

2014-04-07T23:59:59.000Z

480

Novel photoaffinity ligands for the GA-receptor  

SciTech Connect

Previous studies from this laboratory have shown that certain N-substituted phthalimides (NSPs) exhibit GA-like activity in a range of specific bioassays and that bioactive NSPs compete with ({sup 3}H)-GA{sub 4} for soluble binding sites in cucumber homogenates. As such, these compounds may prove useful in the purification and characterization of GA receptor proteins. To this end, five azido-NSPs have been synthesized and are currently being screened for biological activity and photochemical stability. Three azido-NSPs elicit {alpha}-amylase production in barley half-seeds and stimulate tissue elongation in d{sub 5} maize, lettuce, sunflower, and soybean. Further evaluations are in progress and these data as well as the utility of these compounds as photo-affinity ligands will be discussed.

Suttle, J.C.; Hultstrand, J.F.; Tanaka, F.S. (USDA/ARS Biosciences Research Laboratory, Fargo, ND (USA))

1990-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "tn al ga" from the National Library of EnergyBeta (NLEBeta).
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481

The polygallides: Yb{sub 3}Ga{sub 7}Ge{sub 3} and YbGa{sub 4}Ge{sub2}.  

SciTech Connect

Yb{sub 3}Ga{sub 7}Ge{sub 3} and YbGa{sub 4}Ge{sub 2} were obtained from reactions of Yb and Ge in excess liquid gallium. The crystal structure of Yb{sub 3}Ga{sub 7}Ge{sub 3} was refined using X-ray and neutron diffraction data on selected single crystals. Yb{sub 3}Ga{sub 7}Ge{sub 3} crystallizes in the monoclinic space group C2/c with lattice constants a = 12.2261(20) {angstrom}, b = 10.7447(20) {angstrom}, c = 8.4754(17) {angstrom} and {beta} = 110.288(30){sup o} (neutron diffraction data). The crystal structure of Yb{sub 3}Ga{sub 7}Ge{sub 3} is an intergrowth of planar layers of YbGa{sub x}Ge{sub y} and puckered layers of (Ge)n. YbGa{sub 4}Ge{sub 2} crystallizes in a modified PuGa{sub 6} structure type in the tetragonal polar space group I4cm with lattice constants a = b = 5.9874(6) {angstrom} and c = 15.1178(19) {angstrom}. The structure of YbGa{sub 4}Ge{sub 2} is an intergrowth of puckered Ga layers and puckered Ga{sub x}Ge{sub y} layers with Yb atoms residing within the channels formed by the connection of the two layers. Physical properties, resistivity ({rho}), magnetic susceptibility ({chi}) and specific heat (C) were measured for Yb{sub 3}Ga{sub 7}Ge{sub 3}. No magnetic ordering was observed. It was found that at low temperatures, {rho} varied as T{sup 2} and C{alpha}T, indicating Fermi-liquid regime in Yb{sub 3}Ga{sub 7}Ge{sub 3} at low temperatures.

Peter, S. C.; Malliakas, C. D.; Nakotte, H.; Kothapilli, K.; Rayaprol, S.; Schultz, A. J.; Kanatzidis, M. G. (Materials Science Division); ( XSD); (Northwestern Univ.); (Jawaharlal Nehru Centre for Adv. Sci. Res.); (New Mexico State Univ.); (Los Alamos Nat. Lab.); (UGC-DAE Consortium for Sci. Res.)

2012-03-01T23:59:59.000Z

482

Invited Paper GaAs/A1O photonic bandgap material fabrication and characterization  

E-Print Network (OSTI)

semiconductor crystals, photonic crystals do not occur naturally. There are, therefore, several seemingly direct bandgap semiconductors, such as GaAs, A1GaAs, InP, InGaAsP, etc., in which the radiative-dimensional photonic bandgaps for microwave and millimeter-wave radiation, and for shorter optical wavelengths in one

Zhou, Weidong

483

Drift dominated InP/GaP photodiodes Yanning Sun a,*, Aristo Yulius a  

E-Print Network (OSTI)

Drift dominated InP/GaP photodiodes Yanning Sun a,*, Aristo Yulius a , Guohua Li b , Jerry MP photodiodes fabricated on GaP substrate with unique drift dominated design, which can build an electric field throughout the active region by varying the doping concentration. The InP/GaP photodiodes have been grown

Woodall, Jerry M.

484

DISSERTATION DEVICE PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS  

E-Print Network (OSTI)

DISSERTATION DEVICE PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS Submitted by Markus Gloeckler PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS BE ACCEPTED AS FULFILLING IN PART REQUIREMENTS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS Thin-film solar cells have the potential to be an important

Sites, James R.

485

Free carrier induced spectral shift for GaAs filled metallic hole arrays  

E-Print Network (OSTI)

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

New Mexico, University of

486

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy  

E-Print Network (OSTI)

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy A. J. Ptak, L. J-assisted molecular-beam epitaxy to study the dependence of oxygen incorporation on polarity and oxygen partial pressure. Oxygen incorporates at a rate ten times faster on nitrogen-polar GaN than on the Ga polarity

Myers, Tom

487

AlGaAs emitter/GaAs barrier terahertz detector with a 2.3 THz threshold M. B. M. Rinzan and A. G. U. Pereraa  

E-Print Network (OSTI)

NDP Optronics LLC, 236 St. Martins Drive, Mableton, Georgia 30126 H. C. Liu, Z. R. Wasilewski, and M

Perera, A. G. Unil

488

Gas-source molecular beam epitaxial growth and characterization of the (Al,In,Ga)NP/GaP material system and Its applications to light-emitting diodes  

E-Print Network (OSTI)

T.P. , IEE Proceedings-Optoelectronics 144, 1 (1997). Kishof Energy (BTS) and the Optoelectronics Industry Developmentin semiconductor optoelectronics in recent years. Within two

Odnoblyudov, Vladimir

2006-01-01T23:59:59.000Z

489

Measurement of electron-hole friction in an n-doped GaAs/AlGaAs quantum well using optical transient-grating spectroscopy  

SciTech Connect

We use phase-resolved transient grating spectroscopy to measure the drift and diffusion of electron-hole density waves in a semiconductor quantum well. The unique aspects of this optical probe allow us to determine the frictional force between a two-dimensional Fermi liquid of electrons and a dilute gas of holes. Knowledge of electron-hole friction enables prediction of ambipolar dynamics in high-mobility electron systems.

Yang, Luyi; Koralek, J. D.; Orenstein, J.; Tibbetts, D. R.; Reno, J. L.; Lilly, M. P.

2011-04-26T23:59:59.000Z

490

Self-consistent thermal simulation of GaAs/Al0.45Ga0.55As quantum cascade lasers  

Science Journals Connector (OSTI)

This paper presents a self-consistent thermal model for quantum cascade lasers (QCLs) that takes into account the nonuniform heat generation distribution in the active region as well as the temperature dependences of the heat generation rate and thermal ... Keywords: Heating, Monte Carlo, Nonlinear effects, Phonon transport, Quantum cascade lasers, Thermal model

Y. B. Shi; Z. Aksamija; I. Knezevic

2012-03-01T23:59:59.000Z

491

High-resolution X-ray characterization of mid-IR Al0.45Ga0.55As/GaAs Quantum Cascade Laser structures  

Science Journals Connector (OSTI)

Abstract In this paper, the X-ray diffraction profiles of Quantum Cascade Laser (QCL) structures have been investigated. The examined structures were grown by molecular beam epitaxy. The crystallographic characterization was carried out using high resolution X-ray diffractometer. The information about thickness of individual layers and periodicity of the structures was derived from simulation of diffraction profiles calculated using dynamical diffraction theory. The influence of interface roughness on the shape of satellite peaks was studied. The particular attention has been paid to the analysis of the broadening of satellite peaks. The presented results show that broadening is due to the variation of thickness of individual layers.

J. Kubacka-Traczyk; I. Sankowska; O.H. Seeck; K. Kosiel; M. Bugajski

2014-01-01T23:59:59.000Z