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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
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1

AlGaN/GaN-based power semiconductor switches  

E-Print Network [OSTI]

AlGaN/GaN-based high-electron-mobility transistors (HEMTs) have great potential for their use as high efficiency and high speed power semiconductor switches, thanks to their high breakdown electric field, mobility and ...

Lu, Bin, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

2

Reactive codoping of GaAlInP compound semiconductors  

DOE Patents [OSTI]

A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

Hanna, Mark Cooper (Boulder, CO); Reedy, Robert (Golden, CO)

2008-02-12T23:59:59.000Z

3

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

SciTech Connect (OSTI)

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

4

Radiation Hard AlGaN Detectors and Imager  

SciTech Connect (OSTI)

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

5

Impact of electrochemical process on the degradation mechanisms of AlGaN/GaN HEMTs  

E-Print Network [OSTI]

AlGaN/GaN high electron mobility transistors (HEMTs) constitute a new generation of transistors with excellent electrical characteristics and great potential to replace silicon technology in the future, especially in high ...

Gao, Feng, Ph. D. Massachusetts Institute of Technology

2014-01-01T23:59:59.000Z

6

Infrared reflection of GaN and AlGaN thin film heterostructures with AlN buffer layers  

E-Print Network [OSTI]

Infrared reflection of GaN and AlGaN thin film heterostructures with AlN buffer layers C. Wetzel, Nagoya, Japan Received 11 December 1995; accepted for publication 21 February 1996 Infrared reflection, their alloys and potential substrates need to be investigated as well. Here we present a study of the infrared

Wetzel, Christian M.

7

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

SciTech Connect (OSTI)

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

8

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

SciTech Connect (OSTI)

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

9

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

SciTech Connect (OSTI)

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

10

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

11

REGULAR PAPER Improvement of Surge Protection by Using an AlGaN/GaN-Based  

E-Print Network [OSTI]

the metal oxide varistor (MOV) and resistor (R) in a state-of-the-art surge protection circuit), metal oxide varistor (MOV), and transient voltage suppressor (TVS) diodes are the state-of-the- artREGULAR PAPER Improvement of Surge Protection by Using an AlGaN/GaN-Based Metal­Semiconductor­Metal

Chow, Lee

12

AlGaAs/GaAs photovoltaic converters for high power narrowband radiation  

SciTech Connect (OSTI)

AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (? = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021 (Russian Federation); Luque, Antonio [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021, Russia and Instituto de Energia Solar, Universidad Politecnica de Madrid, Madrid (Spain)

2014-09-26T23:59:59.000Z

13

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

SciTech Connect (OSTI)

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

14

AlP/GaP distributed Bragg reflectors  

SciTech Connect (OSTI)

Distributed Bragg reflectors with high reflectivity bands centered at wavelengths from 530 to 690 nm (green to red) based on AlP/GaP quarter-wave stacks are prepared on (001)GaP using gas-source molecular-beam epitaxy. Additionally, the complex refractive index of AlP is measured using spectroscopic ellipsometry within the range of 330-850 nm in order to facilitate an accurate reflector design. Structures consisting of 15 quarter-wave stacks reach a peak reflectance between 95% and 98%, depending on the spectral position of the maximum.

Emberger, Valentin; Hatami, Fariba; Ted Masselink, W. [Department of Physics, Humboldt-Universitaet zu Berlin, Newtonstrasse 15, D-12489 Berlin (Germany); Peters, Sven [Sentech Instruments GmbH, Schwarzschildstr. 2, 12489 Berlin (Germany)

2013-07-15T23:59:59.000Z

15

Height stabilization of GaSb/GaAs quantum dots by Al-rich capping  

SciTech Connect (OSTI)

GaSb quantum dots (QDs) in a GaAs matrix are investigated with cross-sectional scanning tunneling microscopy (X-STM) and photoluminescence (PL). We observe that Al-rich capping materials prevent destabilization of the nanostructures during the capping stage of the molecular beam epitaxy (MBE) growth process and thus preserves the QD height. However, the strain induced by the absence of destabilization causes many structural defects to appear around the preserved QDs. These defects originate from misfit dislocations near the GaSb/GaAs interface and extend into the capping layer as stacking faults. The lack of a red shift in the QD PL suggests that the preserved dots do not contribute to the emission spectra. We suggest that a better control over the emission wavelength and an increase of the PL intensity is attainable by growing smaller QDs with an Al-rich overgrowth.

Smakman, E. P., E-mail: e.p.smakman@tue.nl; Koenraad, P. M. [Department of Applied Physics, Eindhoven University of Technology, Den Dolech 2, 5612 AZ Eindhoven (Netherlands); DeJarld, M.; Martin, A. J.; Millunchick, J. [Department of Material Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Luengo-Kovac, M.; Sih, V. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2014-09-01T23:59:59.000Z

16

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

SciTech Connect (OSTI)

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

17

Local stress-induced effects on AlGaAs/AlOx oxidation front shape  

SciTech Connect (OSTI)

The lateral oxidation of thick AlGaAs layers (>500?nm) is studied. An uncommon shape of the oxide tip is evidenced and attributed to the embedded stress distribution, inherent to the oxidation reaction. Experimental and numerical studies of the internal strain in oxidized Al{sub x}Ga{sub 1?x}As/GaAs structures were carried out by dark-field electron holography and finite element methods. A mapping of the strain distribution around the AlGaAs/oxide interface demonstrates the main role of internal stress on the shaping of the oxide front. These results demonstrate the high relevance of strain in oxide-confined III-V devices, in particular, with over-500-nm thick AlOx confinement layers.

Chouchane, F.; Almuneau, G., E-mail: almuneau@laas.fr; Arnoult, A.; Lacoste, G.; Fontaine, C. [CNRS, LAAS, 7 avenue du colonel Roche, F-31400 Toulouse (France); Univ de Toulouse, UPS, LAAS, F-31400 Toulouse (France); Cherkashin, N. [Univ de Toulouse, UPS, LAAS, F-31400 Toulouse (France); CNRS, CEMES, 29 Rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France)

2014-07-28T23:59:59.000Z

18

Optical spectroscopy of quantum confined states in GaAs/AlGaAs quantum well tubes  

SciTech Connect (OSTI)

We have investigated the quantum confinement of electronic states in GaAs/Al{sub x}Ga{sub 1?x}As nanowire heterostructures which contain radial GaAs quantum wells of either 4nm or 8nm. Photoluminescence and photoluminescence excitation spectroscopy are performed on single nanowires. We observed emission and excitation of electron and hole confined states. Numerical calculations of the quantum confined states using the detailed structural information on the quantum well tubes show excellent agreement with these optical results.

Shi, Teng; Fickenscher, Melodie; Smith, Leigh; Jackson, Howard [Department of Physics, University of Cincinnati, Cincinnati, OH 45221 (United States); Yarrison-Rice, Jan [Department of Physics, Miami University, Oxford, OH 45056 (United States); Gao, Qiang; Tan, Hoe; Jagadish, Chennupati [Department of Electronic Materials and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Etheridge, Joanne [Monash Centre for Electron Microscopy, Monash University, Victoria, 3800 (Australia); Wong, Bryan M. [Materials Chemistry Department, Sandia National Laboratories, Livermore, CA 94551 (United States)

2013-12-04T23:59:59.000Z

19

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

SciTech Connect (OSTI)

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

20

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

Note: This page contains sample records for the topic "al fl 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 (OSTI)

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 Nel, 17 rue des Martyrs, F-38054 Grenoble (France)

2013-12-04T23:59:59.000Z

22

Manipulation of emission energy in GaAs/AlGaAs core-shell nanowires with radial heterostructure  

SciTech Connect (OSTI)

Photoluminescence was studied in GaAs/AlGaAs nanowires (NWs) with different radial heterostructures. We demonstrated that manipulation of the emission energy may be achieved by appropriate choice of the shell structure. The emission at highest energy is generated in the NWs with tunneling thin AlGaAs inner shell and thin GaAs outer shell due to recombination of the photoexcited electrons confined in the outer shell with the holes in the core. Lower energy emission was shown to occur in the NWs with thick outer shell grown in the form of a short-period GaAs/AlGaAs multiple quantum well structure. In this case, the tunneling probability through the multiple quantum wells controls the energy emitted by the NWs. The doping of core results in dominated low energy emission from the GaAs core.

Barbosa, B. G.; Arakaki, H.; Souza, C. A. de; Pusep, Yu. A. [Instituto de Fisica de So Carlos, Universidade de So Paulo, 13560-970 Sao Carlos, SP (Brazil)

2014-03-21T23:59:59.000Z

23

Linear and nonlinear optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell spherical quantum dot  

SciTech Connect (OSTI)

In this work, the optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell quantum dot heterostructure have been studied as a function of Al doping concentrations for cases with and without a hydrogenic donor atom. It has been observed that the absorption coefficient strength and/or resonant absorption wavelength can be adjusted by changing the Al content of inner-barrier and/or outer-barrier regions. Besides, it has been shown that the donor atom has an important effect on the control of the electronic and optical properties of the structure. The results have been presented as a function of the Al contents of the inner-barrier x and outer-barrier y regions and probable physical reasons have been discussed.

Emre Kavruk, Ahmet, E-mail: aekavruk@selcuk.edu.tr, E-mail: aekavruk@gmail.com; Koc, Fatih [Physics Department, Faculty of Sciences, Selcuk University, 42075 Konya (Turkey); Sahin, Mehmet, E-mail: mehmet.sahin@agu.edu.tr, E-mail: mehsahin@gmail.com [Physics Department, Faculty of Sciences, Selcuk University, 42075 Konya (Turkey); Department of Material Sciences and Nanotechnology Engineering, Abdullah Gul University, Kayseri (Turkey)

2013-11-14T23:59:59.000Z

24

Contribution of alloy clustering to limiting the two-dimensional electron gas mobility in AlGaN/GaN and InAlN/GaN heterostructures: Theory and experiment  

SciTech Connect (OSTI)

The influence of alloy clustering on fluctuations in the ground state energy of the two-dimensional electron gas (2DEG) in AlGaN/GaN and InAlN/GaN heterostructures is studied. We show that because of these fluctuations, alloy clustering degrades the mobility even when the 2DEG wavefunction does not penetrate the alloy barrier unlike alloy disorder scattering. A comparison between the results obtained for AlGaN/GaN and InAlN/GaN heterostructures shows that alloy clustering limits the 2DEG mobility to a greater degree in InAlN/GaN heterostructures. Our study also reveals that the inclusion of an AlN interlayer increases the limiting mobility from alloy clustering. Moreover, Atom probe tomography is used to demonstrate the random nature of the fluctuations in the alloy composition.

Ahmadi, Elaheh; Mishra, Umesh K. [Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States); Chalabi, Hamidreza [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Kaun, Stephen W.; Shivaraman, Ravi; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

2014-10-07T23:59:59.000Z

25

Defect studies in ion irradiated AlGaN. | EMSL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phasesData Files Data Files 1B&W Y-12studies in ion irradiated AlGaN.

26

Influence of strain induced by AlN nucleation layer on the electrical properties of AlGaN/GaN heterostructures on Si(111) substrate  

SciTech Connect (OSTI)

The crack-free metal-organic chemical vapor deposition (MOCVD) grown AlGaN/GaN heterostructures on Si substrate with modified growth conditions of AlN nucleation layer (NL) and its influence on the electrical and structural properties of conductive GaN layer are presented. From the Hall electrical measurements, a gradual decrease of two-dimensional electron gas (2DEG) concentration near heterointerface as the function of NL thickness is observed possibly due to the reduction in difference of piezoelectric polarization charge densities between AlGaN and GaN layers. It also indicates that the minimum tensile stress and a relatively less total dislocation density for high pressure grown NL can ensure a 20 % increment in mobility at room temperature irrespective of the interface roughness. The thickness and pressure variations in NL and the subsequent changes in growth mode of AlN contributing to the post growth residual tensile stress are investigated using X-ray diffraction and Raman scattering experiments, respectively. The post growth intrinsic residual stress in top layers of heterostructures arises from lattice mismatches, NL parameters and defect densities in GaN. Hence, efforts to reduce the intrinsic residual stress in current conducting GaN layer give an opportunity to further improve the electrical characteristics of AlGaN/GaN device structures on Si.

Christy, Dennis; Watanabe, Arata; Egawa, Takashi [Research Center for Nano-Device and System, Nagoya Institute of Technology, Nagoya, 466-8555 (Japan)

2014-10-15T23:59:59.000Z

27

Large linear magnetoresistance in a GaAs/AlGaAs heterostructure  

SciTech Connect (OSTI)

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

28

Enhanced optical property in quaternary GaInAsSb/AlGaAsSb quantum wells  

SciTech Connect (OSTI)

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

29

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

SciTech Connect (OSTI)

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

30

Output Harmonic Termination Techniques for AlGaN/GaN HEMT Power Amplifiers Using Active Integrated Antenna Approach  

E-Print Network [OSTI]

Output Harmonic Termination Techniques for AlGaN/GaN HEMT Power Amplifiers Using Active Integrated 1200, Los Angeles, CA 90045 Abstract -- In this paper, effects of output harmonic terminations on PAE termination, we observe a substantial increase in PAE and output power. Further, we demonstrate the high

Itoh, Tatsuo

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

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

34

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

SciTech Connect (OSTI)

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

35

Analysis of the AlGaN/GaN vertical bulk current on Si, sapphire, and free-standing GaN substrates  

SciTech Connect (OSTI)

The vertical bulk (drain-bulk) current (I{sub db}) properties of analogous AlGaN/GaN hetero-structures molecular beam epitaxially grown on silicon, sapphire, and free-standing GaN (FS-GaN) have been evaluated in this paper. The experimental I{sub db} (25-300 Degree-Sign C) have been well reproduced with physical models based on a combination of Poole-Frenkel (trap assisted) and hopping (resistive) conduction mechanisms. The thermal activation energies (E{sub a}), the (soft or destructive) vertical breakdown voltage (V{sub B}), and the effect of inverting the drain-bulk polarity have also been comparatively investigated. GaN-on-FS-GaN appears to adhere to the resistive mechanism (E{sub a} = 0.35 eV at T = 25-300 Degree-Sign C; V{sub B} = 840 V), GaN-on-sapphire follows the trap assisted mechanism (E{sub a} = 2.5 eV at T > 265 Degree-Sign C; V{sub B} > 1100 V), and the GaN-on-Si is well reproduced with a combination of the two mechanisms (E{sub a} = 0.35 eV at T > 150 Degree-Sign C; V{sub B} = 420 V). Finally, the relationship between the vertical bulk current and the lateral AlGaN/GaN transistor leakage current is explored.

Perez-Tomas, A.; Fontsere, A.; Llobet, J. [IMB-CNM-CSIC, Campus UAB, 08193 Bellaterra, Barcelona, CAT (Spain); Placidi, M. [IREC, Jardins Dones de Negre 1, 08930 Sant Adria de Besos, Barcelona (Spain); Rennesson, S.; Chenot, S.; Moreno, J. C.; Cordier, Y. [CRHEA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Baron, N. [CRHEA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); PICOGIGA International, Pl M. Rebuffat, Courtaboeuf 7, 91140 Villejust (France)

2013-05-07T23:59:59.000Z

36

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

37

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

38

Fabrication of Two-Dimensional Photonic Crystals in AlGaInP/GaInP Membranes by Inductively Coupled Plasma Etching  

E-Print Network [OSTI]

The fabrication process of two-dimensional photonic crystals in an AlGaInP/GaInP multi-quantum-well membrane structure is developed. The process includes high resolution electron-beam lithography, pattern transfer into ...

Chen, A.

39

Rapid silicon outdiffusion from SiC substrates during molecular-beam epitaxial growth of AlGaN/GaN/AlN transistor structures  

SciTech Connect (OSTI)

AlGaN/GaN/AlN transistor structures were grown onto SiC substrates by molecular-beam epitaxy. Under aluminum-rich growth conditions for the AlN nucleation layer, undesirable n-type conduction is observed near the GaN/AlN interface for even thick (>1000 A) AlN layers. Silicon is identified as the unwanted dopant from secondary-ion mass spectroscopy measurements. Atomic force microscopy surface maps reveal free aluminum metal on AlN surfaces grown under modest aluminum-rich conditions. It is proposed that rapid silicon migration is caused by molten aluminum reacting with the SiC substrate resulting in dissolved silicon that rapidly migrates through the growing AlN layer. This behavior is significantly reduced using a growth flux ratio of aluminum to reactive nitrogen close to unity. The resulting buffer leakage current of the GaN high electron mobility transistor structure is reduced by more than four orders of magnitude.

Hoke, W.E.; Torabi, A.; Mosca, J.J.; Hallock, R.B.; Kennedy, T.D. [Raytheon RF Components, 362 Lowell Street, Andover, Massachusetts 01810 (United States)

2005-10-15T23:59:59.000Z

40

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

SciTech Connect (OSTI)

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.; zgr, .; Morko, 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

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

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

SciTech Connect (OSTI)

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

42

Terahertz intersubband absorption in non-polar m-plane AlGaN/GaN quantum wells  

SciTech Connect (OSTI)

We demonstrate THz intersubband absorption (15.626.1?meV) in m-plane AlGaN/GaN quantum wells. We find a trend of decreasing peak energy with increasing quantum well width, in agreement with theoretical expectations. However, a blue-shift of the transition energy of up to 14?meV was observed relative to the calculated values. This blue-shift is shown to decrease with decreasing charge density and is, therefore, attributed to many-body effects. Furthermore, a??40% reduction in the linewidth (from roughly 8 to 5?meV) was obtained by reducing the total sheet density and inserting undoped AlGaN layers that separate the wavefunctions from the ionized impurities in the barriers.

Edmunds, C.; Malis, O., E-mail: omalis@purdue.edu [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Shao, J. [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); Shirazi-HD, M. [Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Manfra, M. J. [Physics Department, Purdue University, West Lafayette, Indiana 47907 (United States); Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States); School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2014-07-14T23:59:59.000Z

43

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

SciTech Connect (OSTI)

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

44

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

SciTech Connect (OSTI)

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

45

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

46

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

SciTech Connect (OSTI)

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

47

1.9 kV AlGaN/GaN Lateral Schottky Barrier Diodes on Silicon  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

In this letter, we present AlGaN/GaN lateral Schottky barrier diodes on silicon with recessed anodes and dual field plates. A low specific on-resistance RON,SP (5.12 m?{center_dot}cm2), a low turn-on voltage (1.9 kV), were simultaneously achieved in devices with a 25 ?m anode/cathode separation, resulting in a power figure-of-merit (FOM) BV2/RON,SP of 727 MW{center_dot}cm2. The record high breakdown voltage of 1.9 kV is attributed to the dual field plate structure.

Zhu, Mingda [University of Notre Dame, IN (United States); Song, Bo [Cornell University, Ithaca, NY (United States); Qi, Meng [University of Notre Dame, IN (United States); Hu, Zongyang [University of Notre Dame, IN (United States); Nomoto, Kazuki [University of Notre Dame, IN (United States); Yan, Xiaodong [University of Notre Dame, IN (United States); Cao, Yu [IQE/HRL Labs; Johnson, Wayne [IQE, Westborough, MA (United States); Kohn, Erhard [University of Notre Dame, IN (United States); Jena, Debdeep [Cornell University, Ithaca, NY (United States); Xing, Grace Huili [Cornell University, Ithaca, NY (United States)

2015-04-01T23:59:59.000Z

48

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

49

OMVPE Growth of Quaternary (Al,Ga,In)N for UV Optoelectronics (title change from A)  

SciTech Connect (OSTI)

We report the growth and characterization of quaternary AlGaInN. A combination of photoluminescence (PL), high-resolution x-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) characterizations enables us to explore the contours of constant PL peak energy and lattice parameter as functions of the quaternary compositions. The observation of room temperature PL emission at 351nm (with 20% Al and 5% In) renders initial evidence that the quaternary could be used to provide confinement for GaInN (and possibly GaN). AlGaInN/GrdnN MQW heterostructures have been grown; both XRD and PL measurements suggest the possibility of incorporating this quaternary into optoelectronic devices.

HAN,JUNG; FIGIEL,JEFFREY J.; PETERSEN,GARY A.; MYERS JR.,SAMUEL M.; CRAWFORD,MARY H.; BANAS,MICHAEL ANTHONY; HEARNE,SEAN JOSEPH

2000-01-18T23:59:59.000Z

50

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.

51

High performance double pulse doped pseudomorphic AlGaAs/InGaAs transistors grown by molecular-beam epitaxy  

SciTech Connect (OSTI)

Double pulse doped AlGaAs/InGaAs pseudomorphic high electron mobility transistors have been grown by molecular-beam epitaxy on GaAs substrates. Hall mobilities in excess of 7100 cm{sup 2}/V s at 300 K and 25000 cm{sup 2}/V s at 77 K are obtained with a sheet density of 3 x 10{sup 12} cm{sup {minus}2}. Photoluminescence measurements indicate that two electronic subbands are occupied, and the subband energies are determined. The doping pulses are resolved in secondary ion mass spectrometry measurements. Using a double recess process, transistors have been fabricated that have produced state of the art microwave performance. At 10 GHz a 1.2 mm device has simultaneously achieved a power added efficiency of 70%, output power of 0.97 W, and gain of 10 dB. 17 refs., 5 figs., 1 tab.

Hoke, W.E.; Lyman, P.S.; Labossier, W.H.; Brierley, S.K.; Hendriks, H.T.; Shanfield, S.R.; Aucoin, L.M.; Kazior, T.E. [Raytheon Research Division, Lexington, MA (United States)] [Raytheon Research Division, Lexington, MA (United States)

1992-05-01T23:59:59.000Z

52

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

53

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.

54

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

SciTech Connect (OSTI)

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

55

Plasmonic terahertz detectors based on a high-electron mobility GaAs/AlGaAs heterostructure  

SciTech Connect (OSTI)

In order to characterize magnetic field (B) tunable THz plasmonic detectors, spectroscopy experiments were carried out at liquid helium temperatures and high magnetic fields on devices fabricated on a high electron mobility GaAs/AlGaAs heterostructure. The samples were either gated (the gate of a meander shape) or ungated. Spectra of a photovoltage generated by THz radiation were obtained as a function of B at a fixed THz excitation from a THz laser or as a function of THz photon frequency at a fixed B with a Fourier spectrometer. In the first type of measurements, the wave vector of magnetoplasmons excited was defined by geometrical features of samples. It was also found that the magnetoplasmon spectrum depended on the gate geometry which gives an additional parameter to control plasma excitations in THz detectors. Fourier spectra showed a strong dependence of the magnetoplasmon resonance amplitude on the conduction-band electron filling factor which was explained within a model of the electron gas heating with THz radiation. The study allows to define both the advantages and limitations of plasmonic devices based on high-mobility GaAs/AlGaAs heterostructures for THz detection at low temperatures and high magnetic fields.

Bia?ek, M., E-mail: marcin.bialek@fuw.edu.pl; Witowski, A. M.; Grynberg, M.; ?usakowski, J. [Faculty of Physics, University of Warsaw, ul. Ho?a 69, 00-681 Warsaw (Poland); Orlita, M.; Potemski, M. [Laboratoire National des Champs Magnetiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble (France); Czapkiewicz, M. [Institute of Physics, PAS, al. Lotnikw 32/46, 02-668 Warsaw (Poland); Wrbel, J. [Institute of Physics, PAS, al. Lotnikw 32/46, 02-668 Warsaw (Poland); Faculty of Mathematics and Natural Sciences, Rzeszw University, al. Rejtana 16A, 35-959 Rzeszw (Poland); Umansky, V. [Weizmann Institute of Science, Rehevot 76100 (Israel)

2014-06-07T23:59:59.000Z

56

Green (In,Ga,Al)P-GaP light-emitting diodes grown on high-index GaAs surfaces  

SciTech Connect (OSTI)

We report on green (550560?nm) electroluminescence (EL) from (Al{sub 0.5}Ga{sub 0.5}){sub 0.5}In{sub 0.5}P-(Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P double p-i-n heterostructures with monolayer-scale GaP insertions in the cladding layers and light-emitting diodes based thereupon. The structures are grown side-by-side on high-index and (100) GaAs substrates by molecular beam epitaxy. At moderate current densities (?500?A/cm{sup 2}), the EL intensity of the structures is comparable for all substrate orientations. Opposite to the (100)-grown strictures, the EL spectra of (211) and (311)-grown devices are shifted towards shorter wavelengths (?550?nm at room temperature). At high current densities (>1?kA/cm{sup 2}), a much higher EL intensity is achieved for the devices grown on high-index substrates. The integrated intensity of (311)-grown structures gradually saturates at current densities above 4?kA/cm{sup 2}, whereas no saturation is revealed for (211)-grown structures up to the current densities above 14?kA/cm{sup 2}. We attribute the effect to the surface orientation-dependent engineering of the GaP band structure, which prevents the escape of the nonequilibrium electrons into the indirect conduction band minima of the p-doped (Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P cladding layers.

Ledentsov, N. N., E-mail: nikolay.ledentsov@v-i-systems.com; Shchukin, V. A. [VI Systems GmbH, Hardenbergstr. 7, Berlin D-10623 (Germany); Lyytikinen, J.; Okhotnikov, O. [Optoelectronics Research Centre, Tampere University of Technology, Tampere FI-33720 (Finland); Shernyakov, Yu. M.; Payusov, A. S.; Gordeev, N. Yu.; Maximov, M. V. [A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Schlichting, S.; Nippert, F.; Hoffmann, A. [Institut fr Festkrperphysik, Technische Universitt Berlin, Hardenbergstrasse 36, Berlin D-10623 (Germany)

2014-11-03T23:59:59.000Z

57

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

SciTech Connect (OSTI)

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

58

Ultrasensitive detection of Hg{sup 2+} using oligonucleotide-functionalized AlGaN/GaN high electron mobility transistor  

SciTech Connect (OSTI)

An oligonucleotide-functionalized ion sensitive AlGaN/GaN high electron mobility transistor (HEMT) was fabricated to detect trace amounts of Hg{sup 2+}. The advantages of ion sensitive AlGaN/GaN HEMT and highly specific binding interaction between Hg{sup 2+} and thymines were combined. The current response of this Hg{sup 2+} ultrasensitive transistor was characterized. The current increased due to the accumulation of Hg{sup 2+} ions on the surface by the highly specific thymine-Hg{sup 2+}-thymine recognition. The dynamic linear range for Hg{sup 2+} detection has been determined in the concentrations from 10{sup ?14} to 10{sup ?8} M and a detection limit below 10{sup ?14} M level was estimated, which is the best result of AlGaN/GaN HEMT biosensors for Hg{sup 2+} detection till now.

Cheng, Junjie [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China); Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Li, Jiadong; Miao, Bin; Wu, Dongmin, E-mail: dmwu2008@sinano.ac.cn [i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215125 (China); Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Wang, Jine; Pei, Renjun, E-mail: rjpei2011@sinano.ac.cn [Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031 (China)

2014-08-25T23:59:59.000Z

59

AlGaAs/GaAs quantum well infrared detectors and modulators  

E-Print Network [OSTI]

to the quantum well. This optical transition wavelength lies in the mid infrared region of the spectrum. To get a more realistic picture of the optical transition in a 1-D quantum well, the non-parabolicity of the conduction band of GaAs is taken... into consideration. Further it is seen that with the change in temperature and doping concentration the width and peak of the absorption curve also changes. Based on the above calculations and results an AIGaAs/GaAs quantum well infrared photodetector...

Dave, Digant Praful

1990-01-01T23:59:59.000Z

60

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

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

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

62

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

SciTech Connect (OSTI)

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

63

Study of reflection and transport in the microwave photo-excited GaAs/AlGaAs two dimensional electron system  

SciTech Connect (OSTI)

We present the results of a concurrent experimental study of microwave reflection and transport in the GaAs/AlGaAs two dimensional electron gas system and correlate observed features in the reflection with the observed transport features. The experimental results are compared with expectations based on theory.

Ye, Tianyu; Mani, Ramesh G. [Department of Physics and Astronomy, Georgia State University, Atlanta GA 30303 (United States); Wegscheider, Werner [Laboratorium fr Festkrperphysik, ETH Zrich, 8093 Zrich (Switzerland)

2013-12-04T23:59:59.000Z

64

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

65

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

66

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

SciTech Connect (OSTI)

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

67

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

SciTech Connect (OSTI)

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

68

Short-period superlattices of AlN/Al{sub 0.08}Ga{sub 0.92}N grown on AlN substrates  

SciTech Connect (OSTI)

High-quality short-period superlattices of AlN/Al{sub 0.08}Ga{sub 0.92}N have been grown by gas-source molecular-beam epitaxy with ammonia on Al face of AlN (0001) substrates. A significant reduction was achieved in the dislocation density, down to 3x10{sup 8} cm{sup -2}. Complete removal of residual Al{sub 2}O{sub 3} surface oxide is needed in order to obtain low dislocation density in homoepitaxy on AlN. We show that the presence of Al{sub 2}O{sub 3} islands with the surface coverage as low as 0.2% results in increased dislocation density.

Nikishin, S.A.; Borisov, B.A.; Chandolu, A.; Kuryatkov, V.V.; Temkin, H.; Holtz, M.; Mokhov, E.N.; Makarov, Yu.; Helava, H. [Department of Electrical and Computer Engineering and Nano Tech Center, Texas Tech University, Lubbock, Texas 79409-3102 (United States); Nano Tech Center/Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States); Fox Group Inc., 1154 Stealth Street, Livermore, California 94550 (United States)

2004-11-08T23:59:59.000Z

69

Effects of capping on GaN quantum dots deposited on Al{sub 0.5}Ga{sub 0.5}N by molecular beam epitaxy  

SciTech Connect (OSTI)

The impact of the capping process on the structural and morphological properties of GaN quantum dots (QDs) grown on fully relaxed Al{sub 0.5}Ga{sub 0.5}N templates was studied by transmission electron microscopy. A morphological transition between the surface QDs, which have a pyramidal shape, and the buried ones, which have a truncated pyramid shape, is evidenced. This shape evolution is accompanied by a volume change: buried QDs are bigger than surface ones. Furthermore a phase separation into Al{sub 0.5}Ga{sub 0.5}N barriers was observed in the close vicinity of buried QDs. As a result, the buried QDs were found to be connected with the nearest neighbors by thin Ga-rich zones, whereas Al-rich zones are situated above the QDs.

Korytov, M. [CRHEA-CNRS, rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France) and University of Nice Sophia-Antipolis, Parc Valrose, 06103 Nice (France); Benaissa, M. [CNRST, angle Allal-Fassi/FAR, Madinat al-irfane, 10000 Rabat (Morocco); Brault, J.; Vennegues, P. [CRHEA-CNRS, rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Huault, T. [CRHEA-CNRS, rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne, France and RIBER S.A., 31 rue Casimir Perier, BP 70083, 95873 Bezons Cedex (France); Neisius, T. [CP2M, Faculte Saint Jerome, 13397 Marseille Cedex 20 (France)

2009-04-06T23:59:59.000Z

70

The critical role of growth temperature on the structural and electrical properties of AlGaN/GaN high electron mobility transistor heterostructures grown on Si(111)  

SciTech Connect (OSTI)

This work is dedicated to the study of the growth by ammonia source molecular beam epitaxy of Al{sub x}Ga{sub 1-x}N/GaN high electron mobility transistors on (111) oriented silicon substrates. The effect of growth conditions on the structural and electrical properties of the heterostructures was investigated. It is shown that even a slight variation in the growth temperature of the thick GaN buffer on AlN/GaN stress mitigating layers has a drastic influence on these properties via a counterintuitive effect on the dislocation density. Both in situ curvature measurements and ex situ transmission electron microscopy and x-ray diffraction experiments indicate that the relaxation rate of the lattice mismatch stress increases with the growth temperature but finally results in a higher dislocations density. Furthermore, a general trend appears between the final wafer curvature at room temperature and the threading dislocation density. Finally, the influence of the dislocation density on the GaN buffer insulating properties and the two-dimensional electron gas transport properties at the Al{sub x}Ga{sub 1-x}N/GaN interface is discussed.

Baron, N. [CRHEA-CNRS, rue Bernard Gregory, Parc de Sophia Antipolis, 06560 Valbonne (France); PICOGIGA International, Place Marcel Rebuffat, Parc de Villejust, 91971 Courtaboeuf (France); Cordier, Y.; Chenot, S.; Vennegues, P.; Tottereau, O.; Leroux, M.; Semond, F.; Massies, J. [CRHEA-CNRS, rue Bernard Gregory, Parc de Sophia Antipolis, 06560 Valbonne (France)

2009-02-01T23:59:59.000Z

71

Photoluminescence from InGaAs/GaAs quantum well regrown on a buried patterned oxidized AlAs layer  

SciTech Connect (OSTI)

We present a quasi-planar technological approach for forming a flexible and versatile confinement scheme based on oxidation of AlGaAs buried layers combined to an epitaxial regrowth. This method improves the electrical and optical confinements compared to the lateral oxidation since it allows to define confinement areas from a planar surface. This technique is suitable for the realization of advanced integrated photonic components arrays with close device-to-device spacing such as two-dimensional arrays of vertical-cavity surface-emitting lasers. Our results prove that the oxidation and epitaxial regrowth can be sequenced in a process flow, leading to viable confinement while preserving good radiative properties.

Chouchane, F.; Makhloufi, H.; Calvez, S.; Fontaine, C.; Almuneau, G., E-mail: almuneau@laas.fr [CNRS, LAAS, 7 Avenue du Colonel Roche, F-31400 Toulouse (France); Universit de Toulouse, UPS, F-31400 Toulouse (France)

2014-02-10T23:59:59.000Z

72

Optical and digital GaAs technologies for signal-processing applications; Proceedings of the Meeting, Orlando, FL, Apr. 16-18, 1990  

SciTech Connect (OSTI)

Practical problems that need to be solved for the introduction of optical modules into processing systems are reviewed. Some papers deal with the state of the art in such key devices as Bragg cells, spatial light modulators, and fast CCDs. Issues unique to optical packaging are also highlightened. New architectures to enable real-time operations are demonstrated, and optical interconnects for parallel processors are discussed. Particular attention is given to the status and operational advantages of government-sponsored efforts to upgrade existing military systems with digital GaAs signal processors and the state of the art in computer-aided design and advanced system architectures.

Bendett, M.P.; Butler, D.H., Jr.; Prabhakar, A.; Yang, A.; (Honeywell, Inc., Minneapolis, MN; Booz, Allen and Hamilton, Inc., Bethesda, MD; DARPA, Arlington, VA)

1990-01-01T23:59:59.000Z

73

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

SciTech Connect (OSTI)

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}=(0.090.05) 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 fr Experimentelle Physik, Otto-von-Guericke-Universitt Magdeburg, Universittsplatz 2, 39106 Magdeburg (Germany)

2014-09-21T23:59:59.000Z

74

Evanescent-wave pumped room-temperature single-mode GaAs/AlGaAs core-shell nanowire lasers  

SciTech Connect (OSTI)

Evanescent-wave pumped room-temperature single-mode GaAs/AlGaAs core-shell nanowire lasers are proposed and demonstrated. The nanowires are axially excited by evanescent wave outside a microfiber with a diameter about 10??m via a ns-pulse laser. The lasing emission with a low effective threshold less than 90 nJ is achieved at 868.62?nm along with a linewidth of ?1.8?nm. Moreover, multiple lasing lines in a wavelength range from 852.56?nm to 882.48?nm are observed. The mechanism of diverse lasing wavelengths is revealed. Furthermore, the proposed GaAs/AlGaAs nanowire laser has advantages such as simple structure, easy to operate, and controllable lasing wavelength, tending to be practical in optical communications and integrated photonic circuits.

Wei, Wei; Zhang, Xia, E-mail: xzhang@bupt.edu.cn; Ren, Xiaomin [State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, P.O. Box 66, Beijing 100876 (China); Liu, Yange, E-mail: ygliu@nankai.edu.cn; Wang, Zhi [Key Laboratory of Optical Information and Technology, Ministry of Education and Institute of Modern Optics, Nankai University, Tianjin 300071 (China)

2014-06-02T23:59:59.000Z

75

Molecular-beam epitaxial growth and characterization of inverted, pulse-doped AlGaAs/InGaAs transistor structures  

SciTech Connect (OSTI)

Inverted, pulse-doped AlGaAs/InGaAs pseudomorphic high electron mobility transistor structures were grown by molecular-beam epitaxy. Growth conditions were optimized to improve the quality of the selectively doped AlGaAs layer and to minimize dopant diffusion into the InGaAs channel. The sheet densities and mobilities of the inverted structure were found to be essentially equivalent to those obtained with the normal structure. Shubnikov-de Haas measurements exhibited strong oscillations in the magnetoresistance and plateaus in the Hall resistance. Four optical transitions from the lowest bound electron and hole quantum well states were observed in room-temperature photoluminescence spectra. 15 refs., 4 figs.

Hoke, W.E.; Lyman, P.S.; Brierley, S.K. [Raytheon Research Division, Lexington, MA (United States)] [and others] [Raytheon Research Division, Lexington, MA (United States); and others

1993-05-01T23:59:59.000Z

76

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.

77

Aluminum nitride transitional layer for reducing dislocation density and cracking of AlGaN epitaxial films  

DOE Patents [OSTI]

A denticulated Group III nitride structure that is useful for growing Al.sub.xGa.sub.1-xN to greater thicknesses without cracking and with a greatly reduced threading dislocation (TD) density.

Allerman, Andrew A.; Crawford, Mary H.; Lee, Stephen R.

2013-01-08T23:59:59.000Z

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

Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by germanium doping  

SciTech Connect (OSTI)

We report on electrostatic screening of polarization-induced internal electric fields in AlN/GaN nanowire heterostructures with germanium-doped GaN nanodiscs embedded between AlN barriers. The incorporation of germanium at concentrations above 10{sup 20}?cm{sup 3} shifts the photoluminescence emission energy of GaN nanodiscs to higher energies accompanied by a decrease of the photoluminescence decay time. At the same time, the thickness-dependent shift in emission energy is significantly reduced. In spite of the high donor concentration, a degradation of the photoluminescence properties is not observed.

Hille, P., E-mail: Pascal.Hille@physik.uni-giessen.de; Mener, J.; Becker, P.; Teubert, J.; Schrmann, J.; Eickhoff, M. [I. Physikalisches Institut, Justus-Liebig-Universitt Gieen, Heinrich-Buff-Ring 16, 35392 Gieen (Germany)] [I. Physikalisches Institut, Justus-Liebig-Universitt Gieen, Heinrich-Buff-Ring 16, 35392 Gieen (Germany); Mata, M. de la [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, CAT (Spain)] [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, CAT (Spain); Rosemann, N.; Chatterjee, S. [Faculty of Physics and Materials Science Center, Philipps Universitt Marburg, Renthof 5, 35032 Marburg (Germany)] [Faculty of Physics and Materials Science Center, Philipps Universitt Marburg, Renthof 5, 35032 Marburg (Germany); Magn, C. [Laboratorio de Microscopas Avanzadas, Instituto de Nanociencia de Aragon-ARAID, Universidad de Zaragoza, 50018 Zaragoza (Spain)] [Laboratorio de Microscopas Avanzadas, Instituto de Nanociencia de Aragon-ARAID, Universidad de Zaragoza, 50018 Zaragoza (Spain); Arbiol, J. [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, CAT (Spain) [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, CAT (Spain); Institucio Catalana de Recerca i Estudis Avanats (ICREA), 08010 Barcelona, CAT (Spain)

2014-03-10T23:59:59.000Z

80

Gain broadening mechanism in various GaAlAs laser structures  

SciTech Connect (OSTI)

Coupling of an external grating to a GaAlAs laser results in a strong enhancement of the selected mode and a reduction of the nonselected modes. The spectral form of this reduction is measured with a new sensitive experimental arrangement for three types of laser structures: proton bombarded stripe geometry, V-groove and CSP lasers. This spectral form is determined by the gain curve of the laser only and is independent on the position of the selected mode, i.e., no spectral hole burning is observed at room temperature.

Ruehle, W.; Brosson, P.

1980-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "al fl 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.


81

Atom probe tomography studies of Al{sub 2}O{sub 3} gate dielectrics on GaN  

SciTech Connect (OSTI)

Atom probe tomography was used to achieve three-dimensional characterization of in situ Al{sub 2}O{sub 3}/GaN structures grown by metal organic chemical vapor deposition (MOCVD). Al{sub 2}O{sub 3} dielectrics grown at three different temperatures of 700, 900, and 1000?C were analyzed and compared. A low temperature GaN cap layer grown atop Al{sub 2}O{sub 3} enabled a high success rate in the atom probe experiments. The Al{sub 2}O{sub 3}/GaN interfaces were found to be intermixed with Ga, N, and O over the distance of a few nm. Impurity measurements data showed that the 1000?C sample contains higher amounts of C (4??10{sup 19}/cm{sup 3}) and lower amounts of H (7??10{sup 19}/cm{sup 3}), whereas the 700?C sample exhibits lower C impurities (<10{sup 17}/cm{sup 3}) and higher H incorporation (2.2??10{sup 20}/cm{sup 3}). On comparing with Al{sub 2}O{sub 3} grown by atomic layer deposition (ALD), it was found that the MOCVD Al{sub 2}O{sub 3}/GaN interface is comparatively abrupt. Scanning transmission electron microscopy data showed that the 900?C and 1000?C MOCVD films exhibit polycrystalline nature, while the ALD films were found to be amorphous.

Mazumder, Baishakhi, E-mail: bmazumder@engineering.ucsb.edu; Wu, Feng; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Liu, Xiang; Yeluri, Ramya; Mishra, Umesh K. [Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States)

2014-10-07T23:59:59.000Z

82

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

SciTech Connect (OSTI)

The structure, magnetostriction and damping properties of Fe82Ga(18?x)Alx(x = 0, 5, 8, 12) alloys were analyzed. The anelastic response of Fe18(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 FeGaAl alloy at room temperature was determined by applying a magnetic field and different heat treatment regimes. The substitution of Ga by Al in Fe18% 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 GaAl 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

83

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

84

A geometrical model for the description of the AlN shell morphology in GaN-AlN core-shell nanowires  

SciTech Connect (OSTI)

A geometrical model based on the one formulated by Foxon et al.[J. Cryst. Growth 311, 3423 (2009)] is developed to describe the morphology of AlN shells in GaN-AlN core-shell nanowires grown by plasma-assisted molecular beam epitaxy. The shell aspect ratio is studied as a function of the atomic beam flux incidence angles and of the ratio between Al and N species. The comparison between experimental data and the developed geometrical model suggests the diffusion of about 55% of Al atoms from the side walls to the top surface.

Hestroffer, Karine; Daudin, Bruno [CEA-CNRS Group Nanophysique et Semiconducteurs, Institut Nel/CNRS-Universit J. Fourier and CEA Grenoble, INAC, SP2M, 17 rue des Martyrs, 38 054 Grenoble (France)] [CEA-CNRS Group Nanophysique et Semiconducteurs, Institut Nel/CNRS-Universit J. Fourier and CEA Grenoble, INAC, SP2M, 17 rue des Martyrs, 38 054 Grenoble (France)

2013-12-28T23:59:59.000Z

85

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

E-Print Network [OSTI]

A remarkable progress towards functional ferromagnetic semiconductor materials for spintronics has been achieved in p-type (Ga,Mn)As. Robust hole-mediated ferromagnetism has, however, been observed also in other III-V hosts such as antimonides, Ga...

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

86

Fabrication of quantum point contacts by engraving GaAsAlGaAs heterostructures with a diamond tip  

E-Print Network [OSTI]

by hot-filament chemical vapor deposition of polycrystalline diamond onto a prepat- terned siliconFabrication of quantum point contacts by engraving GaAsAlGaAs heterostructures with a diamond tip for publication 17 July 2002 We use the all-diamond tip of an atomic force microscope for the direct engraving

Hohls, Frank

87

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 Ga...

Johnson, Derek Wade

2014-07-31T23:59:59.000Z

88

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.

89

Migration enhanced lateral epitaxial overgrowth of AlN and AlGaN for high reliability deep ultraviolet light emitting diodes  

SciTech Connect (OSTI)

We report on the growth of low-defect thick films of AlN and AlGaN on trenched AlGaN/sapphire templates using migration enhanced lateral epitaxial overgrowth. Incoherent coalescence-related defects were alleviated by controlling the tilt angle of growth fronts and by allowing Al adatoms sufficient residence time to incorporate at the most energetically favorable lattice sites. Deep ultraviolet light emitting diode structures (310 nm) deposited over fully coalesced thick AlN films exhibited cw output power of 1.6 mW at 50 mA current with extrapolated lifetime in excess of 5000 hours. The results demonstrate substantial improvement in the device lifetime, primarily due to the reduced density of growth defects.

Jain, R.; Sun, W.; Yang, J.; Shatalov, M.; Hu, X.; Sattu, A.; Lunev, A.; Deng, J.; Shturm, I.; Bilenko, Y.; Gaska, R. [Sensor Electronic Technology, Inc., 1195 Atlas Road, Columbia, South Carolina 29209 (United States); Shur, M. S. [Electrical Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy New York 12180 (United States)

2008-08-04T23:59:59.000Z

90

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 (OSTI)

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

91

Effects of Mg-doped AlN/AlGaN superlattices on properties of p-GaN contact layer and performance of deep ultraviolet light emitting diodes  

SciTech Connect (OSTI)

Mg-doped AlN/AlGaN superlattice (Mg-SL) and Mg-doped AlGaN epilayers have been investigated in the 284 nm deep ultraviolet (DUV) light emitting diodes (LEDs) as electron blocking layers. It was found that the use of Mg-SL improved the material quality of the p-GaN contact layer, as evidenced in the decreased density of surface pits and improved surface morphology and crystalline quality. The performance of the DUV LEDs fabricated using Mg-SL was significantly improved, as manifested by enhanced light intensity and output power, and reduced turn-on voltage. The improved performance is attributed to the enhanced blocking of electron overflow, and enhanced hole injection.

Al tahtamouni, T. M., E-mail: talal@yu.edu.jo [Department of Physics, Yarmouk University, Irbid 21163 (Jordan); Lin, J. Y.; Jiang, H. X. [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)] [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2014-04-15T23:59:59.000Z

92

Scattering due to Schottky barrier height spatial fluctuation on two dimensional electron gas in AlGaN/GaN high electron mobility transistors  

SciTech Connect (OSTI)

A scattering mechanism related to the Schottky barrier height (SBH) spatial fluctuation of the two dimensional electron gas (2DEG) in AlGaN/GaN heterostructures is presented. We find that the low field mobility is on the order of 10{sup 4}10{sup 6} cm{sup 2}/Vs. The 2DEG transport properties are found to be influenced by both the mobility and 2DEG density variations caused by the SBH fluctuation. Our results indicate that a uniform Schottky contact is highly desired to minimize the influence of SBH inhomogeneity on the device performance.

Li, Huijie; Liu, Guipeng, E-mail: liugp@semi.ac.cn; Wei, Hongyuan; Jiao, Chunmei; Wang, Jianxia; Zhang, Heng; Dong Jin, Dong; Feng, Yuxia; Yang, Shaoyan, E-mail: sh-yyang@semi.ac.cn; Wang, Lianshan; Zhu, Qinsheng; Wang, Zhan-Guo [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China 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)] [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China 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)

2013-12-02T23:59:59.000Z

93

Anisotropic scattering effect of the inclined misfit dislocation on the two-dimensional electron gas in Al(In)GaN/GaN heterostructures  

SciTech Connect (OSTI)

In this paper, a theory is developed to study the anisotropic scattering effect of the inclined misfit dislocation on the two-dimensional electron gas in Al(In)GaN/GaN heterostructures. The inclined misfit dislocation, which differs from the well-known vertical threading dislocation, has a remarkable tilt angle from the vertical. The predicted electron mobility shows a remarkable anisotropy. It has a maximum mobility value along the direction perpendicular to the projection of the inclined dislocation line, and a minimum mobility value along the direction parallel to the projection. The degree of the anisotropic scattering effect will be even greater with the increase of the tilt angle.

Jin, Dong-Dong [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); Department of Physics, Tsinghua University, Beijing 100084 (China); Wang, Lian-shan, E-mail: ls-wang@semi.ac.cn; Yang, Shao-Yan, E-mail: sh-yyang@semi.ac.cn; Li, Hui-jie; Zhang, Heng; Wang, Jian-xia; Xiang, Ruo-fei; Wei, Hong-yuan; Jiao, Chun-mei; Liu, Xiang-Lin; Zhu, Qin-Sheng, E-mail: qszhu@semi.ac.cn; Wang, Zhan-Guo [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); Zhang, Liu-Wan [Department of Physics, Tsinghua University, Beijing 100084 (China)

2014-01-28T23:59:59.000Z

94

Study of the growth mechanisms of GaN/(Al, Ga)N quantum dots: Correlation between structural and optical properties  

SciTech Connect (OSTI)

The ammonia-based molecular beam epitaxy of GaN/(Al, Ga)N quantum dots is investigated using reflection high-energy electron diffraction, atomic force microscopy, transmission electron microscopy and photoluminescence. The main steps of the formation kinetics are identified and the influence of diffusion and evaporation processes on both the quantum dot and the wetting layer morphology is addressed. The correlation between the optical and structural properties of such structures finally allows for the analysis of matter exchanges between the quantum dots and the wetting layer during capping.

Sergent, S. [CRHEA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Universite de Nice Sophia Antipolis, Parc Valrose, F-06102 Nice Cedex 2 (France); Damilano, B.; Huault, T.; Brault, J.; Tottereau, O.; Vennegues, P.; Leroux, M.; Semond, F.; Massies, J. [CRHEA-CNRS, Rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France); Korytov, M.

2011-03-01T23:59:59.000Z

95

Highly tunable quantum Hall far-infrared photodetector by use of GaAs/Al{sub x}Ga{sub 1?x}As-graphene composite material  

SciTech Connect (OSTI)

We have developed a highly tunable, narrow band far-infrared (FIR) photodetector which utilizes the characteristic merits of graphene and two-dimensional electron gas (2DEG) in GaAs/Al{sub x}Ga{sub 1?x}As heterostructure in the Quantum Hall states (QHS). The heterostructure surface is covered with chemical vapor-deposited graphene, which functions as a transparent top-gate to vary the electron density of the 2DEG. FIR response observed in the vicinity of integer QH regime can be effectively tuned in a wide range of 27102?cm{sup ?1} with a bias voltage less than ?1?V. In addition, we have found that the presence of graphene can genuinely modulate the photoresponse. Our results demonstrate a promising direction for realizing a tunable long-wavelength FIR detector using QHS in GaAs 2DEG/ graphene composite material.

Tang, Chiu-Chun [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2014-11-03T23:59:59.000Z

96

Mid-infrared electro-luminescence and absorption from AlGaN/GaN-based multi-quantum well inter-subband structures  

SciTech Connect (OSTI)

We present electro-modulated absorption and electro-luminescence measurements on chirped AlGaN/GaN-based multi-quantum well inter-subband structures grown by metal-organic vapour phase epitaxy. The absorption signal is a TM-polarized, 70?meV wide feature centred at 230?meV. At medium injection current, a 58?meV wide luminescence peak corresponding to an inter-subband transition at 1450?cm{sup ?1} (180?meV) is observed. Under high injection current, we measured a 4?meV wide structure peaking at 92.5?meV in the luminescence spectrum. The energy location of this peak is exactly at the longitudinal optical phonon of GaN.

Hofstetter, Daniel, E-mail: Daniel.Hofstetter@unine.ch [University of Neuchtel, Institute of Physics, 51 Avenue de Bellevaux, Neuchtel, CH2009 (Switzerland); Bour, David P. [Avogy, Inc., 677 River Oaks Parkway, San Jose, California 95134 (United States); Kirste, Lutz [Fraunhofer Institute for Applied Solid State Physics (IAF), Tullastrasse 72, D-79108 Freiburg i. Brsg. (Germany)

2014-06-16T23:59:59.000Z

97

Effect of exciton oscillator strength on upconversion photoluminescence in GaAs/AlAs multiple quantum wells  

SciTech Connect (OSTI)

We report upconversion photoluminescence (UCPL) in GaAs/AlAs multiple quantum wells. UCPL from the AlAs barrier is caused by the resonant excitation of the excitons in the GaAs well. When the quantum well has sufficient miniband width, UCPL is hardly observed because of the small exciton oscillator strength. The excitation-energy and excitation-density dependences of UCPL intensity show the exciton resonant profile and a linear increase, respectively. These results demonstrate that the observed UCPL caused by the saturated two-step excitation process requires a large number of excitons.

Kojima, Osamu, E-mail: kojima@phoenix.kobe-u.ac.jp; Okumura, Shouhei; Kita, Takashi [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Akahane, Kouichi [National Institute of Information and Communications Technology, 4-2-1 Nukui-kitamachi, Koganei, Tokyo 184-8795 (Japan)

2014-11-03T23:59:59.000Z

98

Quasi-bound states and continuum absorption background of polar Al{sub 0.5}Ga{sub 0.5}N/GaN quantum dots  

SciTech Connect (OSTI)

A theoretical interpretation of the photoluminescence excitation spectra of self-organized polar GaN/(Al,Ga)N quantum dots is presented. A numerical method assuming a realistic shape of the dots and including the built-in electric field effects is developed to calculate their energy structure and hence their optical absorption. The electron and hole spectra show the existence of a set of quasi-bound states that does not originate from the wetting layer and plays a crucial role in the observed absorption spectrum of the GaN/(Al,Ga)N dots. Transitions involving these quasi-bound states and wetting layer states give a sufficient explanation for the observed continuum absorption background. The properties of this absorption band, especially its extension, depend strongly on the dot's size. Our simulation provides a natural explanation of the experimental luminescence excitation spectra of ensembles of dots of different heights. Our theoretical model can be convenient for future optical studies including systems with more complicated potentials.

Elmaghraoui, D., E-mail: elmaghraouidonia@yahoo.fr; Triki, M. [Laboratoire de physique de la matire condens, Facult des sciences de Tunis, Campus universitaire 2092 El Manar (Tunisia); Jaziri, S. [Laboratoire de physique de la matire condens, Facult des sciences de Tunis, Campus universitaire 2092 El Manar (Tunisia); Laboratoire de Physique des Matriaux, Facult des Sciences de Bizerte 7021 Jarzouna (Tunisia); Leroux, M.; Brault, J. [Centre de Recherche sur l'Hetero-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Rue B. Gregory, 06560 Valbonne (France)

2014-07-07T23:59:59.000Z

99

Physics of gate leakage current in N-polar InAlN/GaN heterojunction field effect transistors  

SciTech Connect (OSTI)

A physics based model of the gate leakage current in N-polar InAlN/GaN heterojunction field effect transistors is demonstrated. The model is based on the space charge limited current flow dominated by the effects of deep traps in the InAlN surface layer. The model predicts accurately the gate-leakage measurement data of the N-polar InAlN/GaN device with InAlN cap layer. In the pinch-off state, the gate leakage current conduction through the surface of the device in the drain access region dominates the current flow through the two dimensional electron gas channel. One deep trap level and two levels of shallow traps are extracted by fitting the model results with measurement data.

Goswami, Arunesh; Trew, Robert J.; Bilbro, Griff L. [ECE Department, Box 7911, North Carolina State University, Raleigh, North Carolina 27695-7911 (United States)

2014-10-28T23:59:59.000Z

100

Effect of antimony nano-scale surface-structures on a GaSb/AlAsSb distributed Bragg reflector  

SciTech Connect (OSTI)

Effects of antimony crystallization on the surface of GaSb during low temperature molecular beam epitaxy growth are investigated. The geometry of these structures is studied via transmission electron and atomic force microscopies, which show the surface metal forms triangular-shaped, elongated nano-wires with a structured orientation composed entirely of crystalline antimony. By depositing antimony on a GaSb/AlAsSb distributed Bragg reflector, the field is localized within the antimony layer. Polarization dependent transmission measurements are carried out on these nano-structures deposited on a GaSb/AlAsSb distributed Bragg reflector. It is shown that the antimony-based structures at the surface favor transmission of light polarized perpendicular to the wires.

Husaini, S.; Shima, D.; Ahirwar, P.; Rotter, T. J.; Hains, C. P.; Dang, T.; Bedford, R. G.; Balakrishnan, G. [Air Force Research Laboratory, Sensors Directorate, Wright-Patterson AFB, Dayton, OH 45433 (United States)] [Air Force Research Laboratory, Sensors Directorate, Wright-Patterson AFB, Dayton, OH 45433 (United States)

2013-02-11T23:59:59.000Z

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

Milliwatt operation of AlGaN-based single-quantum-well light emitting diode in the ultraviolet region  

SciTech Connect (OSTI)

By introducing a single-quantum-well active layer and a high-Al-content carrier blocking layer, the output power of an AlGaN-based ultraviolet light-emitting diode has been improved by one order of magnitude. Optical output of 1 mW was achieved at the emission peak wavelength of 341{endash}343 nm. {copyright} 2001 American Institute of Physics.

Nishida, Toshio; Saito, Hisao; Kobayashi, Naoki

2001-06-18T23:59:59.000Z

102

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

103

Review of Scientific instruments InAs/Al0.2Ga0.8Sb Quantum Well Hall Sensors  

E-Print Network [OSTI]

1 Review of Scientific instruments InAs/Al0.2Ga0.8Sb Quantum Well Hall Sensors with improved Boeck, G. Borghs IMEC, Kapeldreef 75, B-3001 Leuven, Belgium Cross-shaped Hall sensors with high. Introduction Hall effect devices are by far the most widely used magnetic sensors today. Their future mainly

Moshchalkov, Victor V.

104

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 AlAs?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.

105

Characteristics of AlN/GaN nanowire Bragg mirror grown on (001) silicon by molecular beam epitaxy  

SciTech Connect (OSTI)

GaN nanowires containing AlN/GaN distributed Bragg reflector (DBR) heterostructures have been grown on (001) silicon substrate by molecular beam epitaxy. A peak reflectance of 70% with normal incidence at 560 nm is derived from angle resolved reflectance measurements on the as-grown nanowire DBR array. The measured peak reflectance wavelength is significantly blue-shifted from the ideal calculated value. The discrepancy is explained by investigating the reflectance of the nanoscale DBRs with a finite difference time domain technique. Ensemble nanowire microcavities with In{sub 0.3}Ga{sub 0.7}N nanowires clad by AlN/GaN DBRs have also been characterized. Room temperature emission from the microcavity exhibits considerable linewidth narrowing compared to that measured for unclad In{sub 0.3}Ga{sub 0.7}N nanowires. The resonant emission is characterized by a peak wavelength and linewidth of 575 nm and 39 nm, respectively.

Heo, Junseok; Bhattacharya, Pallab [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)] [Center for Photonics and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States); Zhou, Zifan [Department of Electrical and Computer Engineering, University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States)] [Department of Electrical and Computer Engineering, University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States); Guo, Wei [Microsystems Engineering, Rochester Institute of Technology, Rochester, New York 14623 (United States)] [Microsystems Engineering, Rochester Institute of Technology, Rochester, New York 14623 (United States); Ooi, Boon S. [Photonics Laboratory, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)] [Photonics Laboratory, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

2013-10-28T23:59:59.000Z

106

High-temperature luminescence in an n-GaSb/n-InGaAsSb/p-AlGaAsSb light-emitting heterostructure with a high potential barrier  

SciTech Connect (OSTI)

The electroluminescent properties of an n-GaSb/n-InGaAsSb/p-AlGaAsSb heterostructure with a high potential barrier in the conduction band (large conduction-band offset) at the n-GaSb/n-InGaAsSb type-II heterointerface ({Delta}E{sub c} = 0.79 eV) are studied. Two bands with peaks at 0.28 and 0.64 eV at 300 K, associated with radiative recombination in n-InGaAsSb and n-GaSb, respectively, are observed in the electroluminescence (EL) spectrum. In the entire temperature range under study, T = 290-480 K, additional electron-hole pairs are formed in the n-InGaAsSb active region by impact ionization with hot electrons heated as a result of the conduction-band offset. These pairs contribute to radiative recombination, which leads to a nonlinear increase in the EL intensity and output optical power with increasing pump current. A superlinear increase in the emission power of the long-wavelength band is observed upon heating in the temperature range T = 290-345 K, and a linear increase is observed at T > 345 K. This work for the first time reports an increase in the emission power of a light-emitting diode structure with increasing temperature. It is shown that this rise is caused by a decrease in the threshold energy of the impact ionization due to narrowing of the band gap of the active region.

Petukhov, A. A., E-mail: andrey-rus29@rambler.ru; Zhurtanov, B. E.; Kalinina, K. V.; Stoyanov, N. D.; Salikhov, H. M.; Mikhailova, M. P.; Yakovlev, Yu. P. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)] [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-09-15T23:59:59.000Z

107

Effects of bias and temperature on the intersubband absorption in very long wavelength GaAs/AlGaAs quantum well infrared photodetectors  

SciTech Connect (OSTI)

The temperature- and bias-dependent photocurrent spectra of very long wavelength GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) are studied using spectroscopic measurements and corresponding theoretical calculations. It is found that the peak response wavelength will shift as the bias and temperature change. Aided by band structure calculations, we propose a model of the double excited states and explain the experimental observations very well. In addition, the working mechanisms of the quasi-bound state confined in the quantum well, including the processes of tunneling and thermionic emission, are also investigated in detail. We confirm that the first excited state, which belongs to the quasi-bound state, can be converted into a quasi-continuum state induced by bias and temperature. These obtained results provide a full understanding of the bound-to-quasi-bound state and the bound-to-quasi-continuum state transition, and thus allow for a better optimization of QWIPs performance.

Liu, X. H.; Zhou, X. H., E-mail: xhzhou@mail.sitp.ac.cn; Li, N.; Liao, K. S.; Huang, L.; Li, Q.; Li, Z. F.; Chen, P. P.; Lu, W. [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu-Tian Road, Shanghai 200083 (China); Wang, L.; Sun, Q. L. [Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

2014-03-28T23:59:59.000Z

108

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

SciTech Connect (OSTI)

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

109

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

110

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

111

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

SciTech Connect (OSTI)

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

112

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

113

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

SciTech Connect (OSTI)

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

114

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

115

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

SciTech Connect (OSTI)

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

116

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

117

Recombination luminescence and trap levels in undoped and Al-doped ZnO thin films on quartz and GaSe (0 0 0 1) substrates  

SciTech Connect (OSTI)

Highlights: Black-Right-Pointing-Pointer ZnO films on GaSe create electron trapping states and PL recombination levels. Black-Right-Pointing-Pointer Zn and Al diffusion in GaSe produces low-energy widening of its PL emission. Black-Right-Pointing-Pointer ZnO:Al films on GaSe lamellas are suitable for gas-discharge lamp applications. -- Abstract: Photoluminescence spectra of ZnO and ZnO:Al (1.00, 2.00 and 5.00 at.%) films on GaSe (0 0 0 1) lamellas and amorphous quartz substrates, obtained by annealing, at 700 K, of undoped and Al-doped metal films, are investigated. For all samples, the nonequilibrium charge carriers recombine by radiative band-to-band transitions with energy of 3.27 eV, via recombination levels created by the monoionized oxygen atoms, forming the impurity band laying in the region 2.00 - 2.70 eV. Al doping induces an additional recombination level at 1.13 eV above the top of the valence band of ZnO films on GaSe substrates. As a result of thermal diffusion of Zn and Al into the GaSe interface layer from ZnO:Al/GaSe heterojunction, electron trap levels located at 0.22 eV and 0.26 eV below the conduction band edge of GaSe, as well as a deep recombination level, responsible for the luminescent emission in the region 1.10 - 1.40 eV, are created.

Evtodiev, I. [Moldova State University, 60 A. Mateevici Str., Chisinau, MD 2009, Republic of Moldova (Moldova, Republic of)] [Moldova State University, 60 A. Mateevici Str., Chisinau, MD 2009, Republic of Moldova (Moldova, Republic of); Caraman, I. [Vasile Alecsandri University of Bacau, 157 Calea Marasesti, RO 600115 Bacau (Romania)] [Vasile Alecsandri University of Bacau, 157 Calea Marasesti, RO 600115 Bacau (Romania); Leontie, L., E-mail: lleontie@uaic.ro [Alexandru Ioan Cuza University of Iasi, Bd. Carol I, Nr. 11, RO 700506 Iasi (Romania); Rusu, D.-I. [Vasile Alecsandri University of Bacau, 157 Calea Marasesti, RO 600115 Bacau (Romania)] [Vasile Alecsandri University of Bacau, 157 Calea Marasesti, RO 600115 Bacau (Romania); Dafinei, A. [Faculty of Physics, University of Bucharest, Platforma Magurele, Str. Fizicienilor nr. 1, CP Mg - 11, Bucharest-Magurele, RO 76900 (Romania)] [Faculty of Physics, University of Bucharest, Platforma Magurele, Str. Fizicienilor nr. 1, CP Mg - 11, Bucharest-Magurele, RO 76900 (Romania); Nedeff, V.; Lazar, G. [Vasile Alecsandri University of Bacau, 157 Calea Marasesti, RO 600115 Bacau (Romania)] [Vasile Alecsandri University of Bacau, 157 Calea Marasesti, RO 600115 Bacau (Romania)

2012-03-15T23:59:59.000Z

118

Systematic study of near-infrared intersubband absorption of polar and semipolar GaN/AlN quantum wells  

SciTech Connect (OSTI)

We report on the observation of intersubband absorption in GaN/AlN quantum well superlattices grown on (1122)-oriented GaN. The absorption is tuned in the 1.5-4.5 {mu}m wavelength range by adjusting the well thickness. The semipolar samples are compared with polar samples with identical well thickness grown during the same run. The intersubband absorption of semipolar samples shows a significant red shift with respect to the polar ones due to the reduction of the internal electric field in the quantum wells. The experimental results are compared with simulations and confirm the reduction of the polarization discontinuity along the growth axis in the semipolar case. The absorption spectral shape depends on the sample growth direction: for polar quantum wells the intersubband spectrum is a sum of Lorentzian resonances, whereas a Gaussian shape is observed in the semipolar case. This dissimilarity is explained by different carrier localization in these two cases.

Machhadani, H. [Institut d'Electronique Fondamentale, Universite Paris-Sud, UMR 8622 CNRS, 91405 Orsay (France); Semiconductor Materials, Department of Physics, Chemistry, and Biology (IFM), Linkoeping University, S-58183 Linkoeping (Sweden); Beeler, M.; Kotsar, Y.; Monroy, E. [CEA-CNRS Group Nanophysique et Semiconducteurs, INAC/SP2M/NPSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Sakr, S.; Warde, E.; Tchernycheva, M.; Julien, F. H. [Institut d'Electronique Fondamentale, Universite Paris-Sud, UMR 8622 CNRS, 91405 Orsay (France); Chauvat, M. P.; Ruterana, P. [CIMAP, UMR 6252, CNRS-ENSICAEN-CEA-UCBN, 6 Bd Marechal Juin, 14050 Caen (France); Nataf, G.; De Mierry, Ph. [CRHEA, UPR 10, 1 rue Bernard Gregory, Sophia Antipolis, 06560 Valbonne (France)

2013-04-14T23:59:59.000Z

119

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

120

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

SciTech Connect (OSTI)

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

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

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

122

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

SciTech Connect (OSTI)

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

123

Fabrication of InAs quantum dots in AlAs/GaAs DBR pillar microcavities for single photon sources  

SciTech Connect (OSTI)

We report the molecular beam epitaxy growth of low-density strain-induced InAs quantum dots (QD) embedded in an AlAs/GaAs distributed Bragg reflector structure for a triggered photon source. By optimal selection of growth temperature, InAs deposited thickness and other experimental parameters, it is possible to grow low density (10/{mu}m{sup 2}) InAs quantum dots with a suitable emission wavelength for a triggered photon source. The empirical formulas for the refractive indices of AlAs and GaAs materials at high temperature over a wide wavelength range are constructed by combining high resolution x-ray diffraction, dynamic optical reflectivity, and optical reflectivity spectrum techniques. Utilizing the electron-beam lithography and electron-cyclotron-resonance plasma etching techniques, a micropost microcavity with the top diameter of 0.6 {mu}m and the post height of 4.2 {mu}m has been fabricated. Narrow, spectrally limited single QD emission embedded in a micropost microcavity is observed in the photoluminescence.

Zhang Bingyang; Solomon, Glenn S.; Pelton, Matthew; Plant, Jocelyn; Santori, Charles; Vuckovic, Jelena; Yamamoto, Yoshihisa [Quantum Entanglement Project, ICORP, JST, Edward L. Ginzton Laboratory, Stanford University, Stanford, California 94305-4085 (United States)

2005-04-01T23:59:59.000Z

124

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

125

Luminescence and superradiance in electron-beam-excited Al{sub x}Ga{sub 1?x}N  

SciTech Connect (OSTI)

Luminescence and superradiance characteristics of 0.51.2-?m thick Al{sub x}Ga{sub 1?x}N films grown by molecular-beam epitaxy on sapphire substrates were studied under excitation of the films with low-energy (<20?keV) and high-energy (170?keV) electron beams. In both cases, the luminescence spectra looked quite similarly; they exhibited a band-edge luminescence with x-dependent wavelength ranging from 365?nm to 310?nm and a broadband emission taking over the whole visible spectral region. Superradiance within the broad band was obtained by pumping the samples with powerful an electron beam in the form of an open-discharge-generated filament.

Bokhan, P. A.; Gugin, P. P.; Zakrevsky, Dm. E.; Malin, T. V. [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 13, Lavrentieva av., Novosibirsk 630090 (Russian Federation); Zhuravlev, K. S.; Osinnykh, I. V. [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 13, Lavrentieva av., Novosibirsk 630090 (Russian Federation); Novosibirsk State University, 2 Pirogova Str., Novosibirsk 630090 (Russian Federation); Solomonov, V. I.; Spirina, A. V. [Institute of Electrophysics, Ural Division of the Russian Academy of Sciences, 106, Amundsen str., Ekaterinburg 620016 (Russian Federation)

2014-09-21T23:59:59.000Z

126

Stochastic dynamic systems fl T. Soderstrom, 1997  

E-Print Network [OSTI]

Stochastic dynamic systems Chapter 5 c fl T. S¨oderstr¨om, 1997 1 Optimal estimation ffl The conditional mean ffl Best linear estimate ffl ML estimation c fl T. S¨oderstr¨om, 1997 2 Optimal estimation criterion 2. Symmetric cond pdf c fl T. S¨oderstr¨om, 1997 3 Best linear estimate Given Ex = mx ; Ey = my E

Flener, Pierre

127

SOLID SOLUTION EFFECTS ON THE THERMAL PROPERTIES IN THE MgAl2O4-MgGa2O4  

SciTech Connect (OSTI)

Solid solution eects on thermal conductivity within the MgO-Al2O3-Ga2O3 system were studied. Samples with systematically varied additions of MgGa2O4 to MgAl2O4 were prepared and the laser ash technique was used to determine thermal diusivity at temperatures between 200C and 1300C. Heat capacity as a function of temperature from room temperature to 800C was also determined using dierential scanning calorimetry. Solid solution in the MgAl2O4-MgGa2O4 system decreases the thermal conductivity up to 1000C. At 200C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. At 1000C the thermal conductivity decreased 13% with a 5 mol% addition. Steady state calculations showed a 12.5% decrease in heat ux with 5 mol% MgGa2O4 considered across a 12 inch thickness.

O'Hara, Kelley [University of Missouri, Rolla; Smith, Jeffrey D [ORNL; Sander, Todd P. [Missouri University of Science and Technology; Hemrick, James Gordon [ORNL

2013-01-01T23:59:59.000Z

128

Atomic layer deposition of Al{sub 2}O{sub 3} on GaSb using in situ hydrogen plasma exposure  

SciTech Connect (OSTI)

In this report, we study the effectiveness of hydrogen plasma surface treatments for improving the electrical properties of GaSb/Al{sub 2}O{sub 3} interfaces. Prior to atomic layer deposition of an Al{sub 2}O{sub 3} dielectric, p-GaSb surfaces were exposed to hydrogen plasmas in situ, with varying plasma powers, exposure times, and substrate temperatures. Good electrical interfaces, as indicated by capacitance-voltage measurements, were obtained using higher plasma powers, longer exposure times, and increasing substrate temperatures up to 250 Degree-Sign C. X-ray photoelectron spectroscopy reveals that the most effective treatments result in decreased SbO{sub x}, decreased Sb, and increased GaO{sub x} content at the interface. This in situ hydrogen plasma surface preparation improves the semiconductor/insulator electrical interface without the use of wet chemical pretreatments and is a promising approach for enhancing the performance of Sb-based devices.

Ruppalt, Laura B.; Cleveland, Erin R.; Champlain, James G.; Prokes, Sharka M.; Brad Boos, J.; Park, Doewon; Bennett, Brian R. [Electronics Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2012-12-03T23:59:59.000Z

129

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

SciTech Connect (OSTI)

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

130

GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al{sub 2}O{sub 3} powder  

SciTech Connect (OSTI)

Surface-textured InGaN/GaN light-emitting diodes (LEDs) coated with transparent Al{sub 2}O{sub 3} powder were fabricated by natural lithography combined with inductively coupled plasma etching. For surface texturing, 300 nm size Al{sub 2}O{sub 3} powder is used as an etching mask by simply coating the surface using a spin-coating process. Also, the powders are left on the surface after surface texturing to further increase extraction efficiency. At 20 mA, the light output power of the textured indium tin oxide (ITO) InGaN/GaN LEDs coated with the Al{sub 2}O{sub 3} powder is enhanced by {approx}112% compared with the conventional nontextured ITO LED. The enhanced light output power is attributed to the improved extraction efficiency resulting from an overall decrease in the total internal reflection due to the textured surface and the Al{sub 2}O{sub 3} powder coating.

Kim, T. K.; Kim, S. H.; Yang, S. S.; Son, J. K.; Lee, K. H.; Hong, Y. G.; Shim, K. H.; Yang, J. W.; Lim, K. Y.; Yang, G. M. [Department of Semiconductor and Chemical Engineering and Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Bae, S. J. [Optowell Co., Ltd., 308, Semiconductor Physics Research Center, 664-14, Dukjin-Dong, Dukjin-Gu, Jeonju 561-756 (Korea, Republic of)

2009-04-20T23:59:59.000Z

131

Variable-gap selective photocells based on Ga/sub 1-x/Al/sub x/As:Ge:Te p-n structures  

SciTech Connect (OSTI)

Doping of Ga/sub 1-x/Al/sub x/As solid solutions with Ge and Te increased the steepness of the fundamental absorption edge and this reduced the width of the quantum photosensitivity spectra of variable-gap selective p-n junction photocells made by depositing epitaxial films of these solid solutions on n-type GaAs substrates. The current-voltage and load characteristics of the photocells were detemined. The efficiency of conversion of the optical into electrical energy was 0.42--0.43 for the photocells with wider photosensitivity spectra and 0.3 for those with the narrowest spectra.

Bessolov, V.N.; Danilova, T.N.; Imenkov, A.N.; Tsarenkov, B.V.; Yakovlev, Y.P.

1980-08-01T23:59:59.000Z

132

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 (OSTI)

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}/Vs to 2.71??10{sup 3}?cm{sup 2}/Vs 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

133

Stochastic dynamic systems fl T. Soderstrom, 1997  

E-Print Network [OSTI]

Stochastic dynamic systems Chapter 2 c fl T. S¨oderstr¨om, 1997 1 Some probability theory ffl Basic facts ffl Conditional distributions ffl Complex­valued Gaussian variables c fl T. S¨oderstr¨om, 1997 2) increasing ffl limx!1 F(x) = 1 ffl lim x!\\Gamma1 F (x) = 0 c fl T. S¨oderstr¨om, 1997 3 Random variables

Flener, Pierre

134

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 (OSTI)

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 fr Festkrperelektronik, Hausvogteiplatz 57, 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 Universit de Toulouse, 29 rue J. Marvig, 31055 Toulouse (France)

2014-02-21T23:59:59.000Z

135

Experimental study of frequency multipliers based on a GaAs/AlAs semiconductor superlattices in the terahertz frequency range  

SciTech Connect (OSTI)

Frequency multipliers based on a GaAs/AlAs semiconductor quantum superlattice have been experimentally studied. The power spectrum of the harmonics in the output signal from a multiplier with an input-signal frequency of 140-160 GHz has been measured. Planar diodes with a small active region (an area of 1-2 {mu}m{sup 2}) have been used in this study. For fabrication of the diodes, structures of heavily doped superlattices with the miniband width 24 meV have been used, these structures were grown by the molecular-beam epitaxy method. Measurements have been conducted using a BOMEM DA3.36 Fourier spectrometer equipped with a detector based on a bolometer cooled to the temperature of liquid helium. The results of the measurements have been used to plot the dependences of the power of the harmonics on the frequency in the range from 0.4 to 8.1 THz. It has been found that the character of the microwave-power distribution over the number of harmonics is close to the spectrum of a sequence of sign-alternating pulses which appear in the diode circuit when the applied voltage of the input signal exceeds the threshold of the diode. The minimal time of establishment of the pulse front and pulse duration are equal to 123 and 667 fs, respectively.

Paveliev, D. G., E-mail: pavelev@rf.unn.ru; Koshurinov, Y. I.; Ivanov, A. S. [Lobachevskii State University of Nizhny Novgorod (Russian Federation); Panin, A. N.; Vax, V. L.; Gavrilenko, V. I.; Antonov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Ustinov, V. M. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Zhukov, A. E. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation)

2012-01-15T23:59:59.000Z

136

Nanoscale-accuracy transfer printing of ultra-thin AlInGaN light-emitting diodes onto mechanically flexible substrates  

SciTech Connect (OSTI)

The transfer printing of 2 ?m-thick aluminum indium gallium nitride (AlInGaN) micron-size light-emitting diodes with 150?nm (14?nm) minimum spacing is reported. The thin AlInGaN structures were assembled onto mechanically flexible polyethyleneterephthalate/polydimethylsiloxane substrates in a representative 16 16 array format using a modified dip-pen nano-patterning system. Devices in the array were positioned using a pre-calculated set of coordinates to demonstrate an automated transfer printing process. Individual printed array elements showed blue emission centered at 486?nm with a forward-directed optical output power up to 80??W (355 mW/cm{sup 2}) when operated at a current density of 20?A/cm{sup 2}.

Trindade, A. J., E-mail: antonio.trindade@strath.ac.uk; Guilhabert, B.; Massoubre, D.; Laurand, N.; Gu, E.; Watson, I. M.; Dawson, M. D. [Institute of Photonics, SUPA, University of Strathclyde, 106 Rottenrow, Glasgow G4 0NW (United Kingdom)] [Institute of Photonics, SUPA, University of Strathclyde, 106 Rottenrow, Glasgow G4 0NW (United Kingdom); Zhu, D.; Humphreys, C. J. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)] [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom)

2013-12-16T23:59:59.000Z

137

Analysis of the causes of the decrease in the electroluminescence efficiency of AlGaInN light-emitting-diode heterostructures at high pumping density  

SciTech Connect (OSTI)

The study is devoted to theoretical explanation of a decrease in the electroluminescence efficiency as the pump current increases, which is characteristic of light-emitting-diode (LED) heterostructures based on AlInGaN. Numerical simulation shows that the increase in the external quantum efficiency at low current densities J {approx} 1 A/cm{sup 2} is caused by the competition between radiative and nonradiative recombination. The decrease in the quantum efficiency at current densities J > 1 A/cm{sup 2} is caused by a decrease in the efficiency of hole injection into the active region. It is shown that the depth of the acceptor energy level in the AlGaN emitter, as well as low electron and hole mobilities in the p-type region, plays an important role in this effect. A modified LED heterostructure is suggested in which the efficiency decrease with the pump current should not occur.

Rozhansky, I. V., E-mail: igor@quantum.ioffe.ru; Zakheim, D. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2006-07-15T23:59:59.000Z

138

Estimation of the internal electric field inside (11-22) semipolar GaN/Al{sub 0.5}Ga{sub 0.5}N nanostructures and the radiative efficiency at low temperature  

SciTech Connect (OSTI)

We report on time-integrated and resolved photoluminescence data on self-assembled semipolar (11-22) GaN nanostructures embedded in Al{sub 0.5}Ga{sub 0.5}N. It is confirmed that the internal electric field is reduced for semipolar (11-22) orientation. It is shown in particular that the value of the electric field is 450500?kV/cm for this orientation. The photoluminescence decay time of excitons is used as a probe of the reduction of the internal electric field in the case of semipolar GaN nanostructures. The measured decays are not only controlled by radiative lifetimes, which depend on the fields inside GaN nanostructures, but also on the nonradiative escape of carriers through barriers. The correspondent decay time is found equal to 330 ps. By the study of the decay time as a function of the emission energy, we can determine the evolution of the internal quantum efficiency as a function of the nanostructures height (energy) and to have access to the nonradiative lifetime at low temperature.

Kahouli, Abdelkarim, E-mail: abdelkarim.kahouli@yahoo.fr; Kriouche, Nasser [Universit de Nice Sophia Antipolis, 06108 Nice Cedex 2 (France)

2014-05-21T23:59:59.000Z

139

A 77 GHz Transceiver for Automotive Radar System Using a120nm In AlAs/In GaAs Metamorphic HEMTs  

E-Print Network [OSTI]

A 77 GHz Transceiver for Automotive Radar System Using a120nm 0.4 0.35 In AlAs/In GaAs Metamorphic-mail:ykwon@snu.ac.kr) Abstract -- In this work, we demonstrate a compact 77GHz single-chip transceiver for an automotive radar at the transmitter and a 5dB conversion gain at the receiver. Index Terms -- Automotive radar, 77GHz, MHEMT, MMIC

Kwon, Youngwoo

140

On the origin of the two-dimensional electron gas at AlGaN/GaN heterojunctions and its influence on recessed-gate metal-insulator-semiconductor high electron mobility transistors  

SciTech Connect (OSTI)

It is commonly accepted that interface states at the passivation surface of AlGaN/GaN heterostructures play an important role in the formation of the 2DEG density. Several interface state models are cited throughout literature, some with discrete levels, others with different kinds of distributions, or a combination of both. The purpose of this article is to compare the existing interface state models with both direct and indirect measurements of these interface states from literature (e.g., through the hysteresis of transfer characteristics of Metal-Insulator-Semiconductor High Electron Mobility Transistors (MISHEMTs) employing such an interface in the gate region) and Technology Computer Aided Design (TCAD) simulations of 2DEG densities as a function of the AlGaN thickness. The discrepancies between those measurements and TCAD simulations (also those commonly found in literature) are discussed. Then, an alternative model inspired by the Disorder Induced Gap State model for compound semiconductors is proposed. It is shown that defining a deep border trap inside the insulator can solve these discrepancies and that this alternative model can explain the origin of the two dimensional electron gas in combination with a high-quality interface that, by definition, has a low interface state density.

Bakeroot, B., E-mail: Benoit.Bakeroot@elis.ugent.be [Centre for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 914a, 9052 Gent (Belgium); You, S.; Van Hove, M.; De Jaeger, B.; Geens, K.; Stoffels, S.; Decoutere, S. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Wu, T.-L.; Hu, J. [imec, Kapeldreef 75, 3001 Leuven (Belgium); Department of Electrical Engineering, KU Leuven, 3001 Leuven (Belgium)

2014-10-07T23:59:59.000Z

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

Importance of growth temperature on achieving lattice-matched and strained InAlN/GaN heterostructure by plasma-assisted molecular beam epitaxy  

SciTech Connect (OSTI)

We investigate the role of growth temperature on the optimization of lattice-matched In{sub 0.17}Al{sub 0.83}N/GaN heterostructure and its structural evolutions along with electrical transport studies. The indium content gradually reduces with the increase of growth temperature and approaches lattice-matched with GaN having very smooth and high structural quality at 450C. The InAlN layers grown at high growth temperature (480C) retain very low Indium content of ? 4 % in which cracks are mushroomed due to tensile strain while above lattice matched (>17%) layers maintain crack-free compressive strain nature. The near lattice-matched heterostructure demonstrate a strong carrier confinement with very high two-dimensional sheet carrier density of ?2.9 10{sup 13} cm{sup ?2} with the sheet resistance of ?450 ?/? at room temperature as due to the manifestation of spontaneous polarization charge differences between InAlN and GaN layers.

Jeganathan, K., E-mail: kjeganathan@yahoo.com [Centre for Nanoscience and Nanotechnology, School of Physics, Bharathidasan University, Tiruchirappalli-620 024, Tamil Nadu (India); Shimizu, M., E-mail: mitsu.shimizu@aist.go.jp [Advanced Power Electronics Research Center, National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan. (Japan)

2014-09-15T23:59:59.000Z

142

Stochastic dynamic systems fl T. Soderstrom, 1997  

E-Print Network [OSTI]

Stochastic dynamic systems Chapter 10 c fl T. S¨oderstr¨om, 1997 1 Optimal stochastic control ffl controllers c fl T. S¨oderstr¨om, 1997 2 Optimal stochastic control ­ some illustrative examples System x¨oderstr¨om, 1997 3 Optimal stochastic control ­ Deterministic system Criterion J = x 2 (N) = [ax(N \\Gamma 1) + bu

Flener, Pierre

143

Optical properties of a-plane (Al, Ga)N/GaN multiple quantum wells grown on strain engineered Zn{sub 1-x}Mg{sub x}O layers by molecular beam epitaxy  

SciTech Connect (OSTI)

Nonpolar (1120) Al{sub 0.2}Ga{sub 0.8}N/GaN multiple quantum wells (MQWs) have been grown by molecular beam epitaxy on (1120) Zn{sub 0.74}Mg{sub 0.26}O templates on r-plane sapphire substrates. The quantum wells exhibit well-resolved photoluminescence peaks in the ultra-violet region, and no sign of quantum confined Stark effect is observed in the complete multiple quantum well series. The results agree well with flat band quantum well calculations. Furthermore, we show that the MQW structures are strongly polarized along the [0001] direction. The origin of the polarization is discussed in terms of the strain anisotropy dependence of the exciton optical oscillator strengths.

Xia, Y.; Vinter, B.; Chauveau, J.-M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France); University of Nice Sophia-Antipolis, 06103 Nice (France); Brault, J.; Nemoz, M.; Teisseire, M.; Leroux, M. [CRHEA-CNRS, Rue Bernard Gregory, 06560 Valbonne (France)

2011-12-26T23:59:59.000Z

144

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

SciTech Connect (OSTI)

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

145

AL  

E-Print Network [OSTI]

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

146

Role of the dielectric for the charging dynamics of the dielectric/barrier interface in AlGaN/GaN based metal-insulator-semiconductor structures under forward gate bias stress  

SciTech Connect (OSTI)

The high density of defect states at the dielectric/III-N interface in GaN based metal-insulator-semiconductor structures causes tremendous threshold voltage drifts, ?V{sub th}, under forward gate bias conditions. A comprehensive study on different dielectric materials, as well as varying dielectric thickness t{sub D} and barrier thickness t{sub B}, is performed using capacitance-voltage analysis. It is revealed that the density of trapped electrons, ?N{sub it}, scales with the dielectric capacitance under spill-over conditions, i.e., the accumulation of a second electron channel at the dielectric/AlGaN barrier interface. Hence, the density of trapped electrons is defined by the charging of the dielectric capacitance. The scaling behavior of ?N{sub it} is explained universally by the density of accumulated electrons at the dielectric/III-N interface under spill-over conditions. We conclude that the overall density of interface defects is higher than what can be electrically measured, due to limits set by dielectric breakdown. These findings have a significant impact on the correct interpretation of threshold voltage drift data and are of relevance for the development of normally off and normally on III-N/GaN high electron mobility transistors with gate insulation.

Lagger, P., E-mail: peter.lagger@infineon.com [Infineon Technologies Austria AG, Siemensstrae 2, 9500 Villach (Austria); Institute of Solid State Electronics, Vienna University of Technology, Floragasse 7, 1040 Wien (Austria); Steinschifter, P.; Reiner, M.; Stadtmller, M.; Denifl, G.; Ostermaier, C. [Infineon Technologies Austria AG, Siemensstrae 2, 9500 Villach (Austria); Naumann, A.; Mller, J.; Wilde, L.; Sundqvist, J. [Fraunhofer IPMS-CNT, Knigsbrcker Strae 178, 01099 Dresden (Germany); Pogany, D. [Institute of Solid State Electronics, Vienna University of Technology, Floragasse 7, 1040 Wien (Austria)

2014-07-21T23:59:59.000Z

147

Analysis of different tunneling mechanisms of In{sub x}Ga{sub 1?x}As/AlGaAs tunnel junction light-emitting transistors  

SciTech Connect (OSTI)

The electrical and optical characteristics of tunnel junction light-emitting transistors (TJLETs) with different indium mole fractions (x?=?5% and 2.5%) of the In{sub x}Ga{sub 1?x}As base-collector tunnel junctions have been investigated. Two electron tunneling mechanisms (photon-assisted or direct tunneling) provide additional currents to electrical output and resupply holes back to the base region, resulting in the upward slope of I-V curves and enhanced optical output under forward-active operation. The larger direct tunneling probability and stronger Franz-Keldysh absorption for 5% TJLET lead to higher collector current slope and less optical intensity enhancement when base-collector junction is under reverse-biased.

Wu, Cheng-Han [Graduate Institute of Electronics Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan (China); Wu, Chao-Hsin, E-mail: chaohsinwu@ntu.edu.tw [Graduate Institute of Electronics Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan (China); Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 106, Taiwan (China)

2014-10-27T23:59:59.000Z

148

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

149

Growth, microstructure, and luminescent properties of direct-bandgap InAlP on relaxed InGaAs on GaAs substrates  

E-Print Network [OSTI]

Direct-bandgap InAlP alloy has the potential to be an active material in nitride-free yellow-green and amber optoelectronics with applications in solid-state lighting, display devices, and multi-junction solar cells. We ...

Beaton, D. A.

150

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

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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.

Rbola, Alejandro; Fong, Dillon D.; Eastman, Jeffrey A.; ?t, Serdar; Zapol, Peter

2013-06-01T23:59:59.000Z

151

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.

152

High magnetic field studies of charged exciton localization in GaAs/Al{sub x}Ga{sub 1?x}As quantum wells  

SciTech Connect (OSTI)

We report on low temperature, polarization resolved, high magnetic field (up to 23?T) photoluminescence experiments on high mobility asymmetric GaAs quantum wells. At high magnetic fields, we detect two strong emission lines of the neutral and positively charged excitons (X and X{sup +}) and a series of weaker lines of the excitons bound to ionized acceptors (AX{sup ?}). From polarization energy splittings of these lines, we determine the hole Land factors (g{sub h}) of different complexes. For X and X{sup +}, g{sub h} initially grows with magnetic field and then saturates at g{sub h}?=?0.88 and 1.55, respectively; for AX{sup ?}'s, g{sub h} begins from a high value (from 6 to 11 at zero field) and decreases with the field growth. This contrasting behavior is traced to the structure of valence band Landau levels, calculated numerically in the Luttinger model, beyond axial approximation. This points to the coexistence (in the same well) of mobile X and X{sup +} with localized and interface-pressed AX{sup ?} states.

Jadczak, J.; Bryja, L., E-mail: leszek.bryja@pwr.edu.pl; Ryczko, K.; Kubisa, M.; Wjs, A. [Institute of Physics, Wroc?aw University of Technology, 50-370 Wroclaw (Poland); Potemski, M. [Laboratoire National des Champs Magntiques Intenses, CNRS-UJF-UPS-INSA, Grenoble (France); Liu, F. [Experimentelle Physik 2, Technische Universitt Dortmund, D-44221 Dortmund (Germany); Yakovlev, D. R.; Bayer, M. [Experimentelle Physik 2, Technische Universitt Dortmund, D-44221 Dortmund (Germany); Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Nicoll, C. A.; Farrer, I.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 OHE (United Kingdom)

2014-09-15T23:59:59.000Z

153

Anti-site disorder and improved functionality of Mn{sub 2}NiX (X = Al, Ga, In, Sn) inverse Heusler alloys  

SciTech Connect (OSTI)

Recent first-principles calculations have predicted Mn{sub 2}NiX (X?=?Al, Ga, In, Sn) alloys to be magnetic shape memory alloys. Moreover, experiments on Mn{sub 2}NiGa and Mn{sub 2}NiSn suggest that the alloys deviate from the perfect inverse Heusler arrangement and that there is chemical disorder at the sublattices with tetrahedral symmetry. In this work, we investigate the effects of such chemical disorder on phase stabilities and magnetic properties using first-principles electronic structure methods. We find that except Mn{sub 2}NiAl, all other alloys show signatures of martensitic transformations in presence of anti-site disorder at the sublattices with tetrahedral symmetry. This improves the possibilities of realizing martensitic transformations at relatively low fields and the possibilities of obtaining significantly large inverse magneto-caloric effects, in comparison to perfect inverse Heusler arrangement of atoms. We analyze the origin of such improvements in functional properties by investigating electronic structures and magnetic exchange interactions.

Paul, Souvik; Kundu, Ashis; Ghosh, Subhradip, E-mail: subhra@iitg.ernet.in [Department of Physics, Indian Institute of Technology Guwahati, Guwahati, Assam 781039 (India); Sanyal, Biplab [Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala (Sweden)

2014-10-07T23:59:59.000Z

154

Transport in GaAs/Al{sub x}Ga{sub 1-x}As superlattices with narrow forbidden minibands: Low-frequency negative differential conductivity and current oscillations  

SciTech Connect (OSTI)

Current-voltage characteristics have been measured and low-frequency current instabilities have been studied for GaAs/Al{sub x}Ga{sub 1-x}As superlattices with narrow forbidden minibands. At relatively low electric fields, a saw-like structure for current-voltage characteristics with alternating portions of positive and negative differential conductivity and spontaneous generation of low-frequency current oscillations with a complex frequency spectrum (varying from discrete to continuous) are observed. It is shown that the observed specific features of electron transport are caused by the spatial-temporal dynamics of electric-field domains (dipoles and monopoles). The effects of the bifurcation, hysteresis, and multistability of current-voltage characteristics are also observed. At high fields, regular features are observed and identified in the current-voltage characteristics; these features are caused by resonance tunneling of electrons between the levels of the Wannier-Stark ladders belonging to quantum wells separated by several periods.

Andronov, A. A., E-mail: andron@ipm.sci-nnov.ru; Dodin, E. P.; Zinchenko, D. I.; Nozdrin, Yu. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

2009-02-15T23:59:59.000Z

155

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 (OSTI)

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

156

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

SciTech Connect (OSTI)

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

157

The Essentials for GA Water Planning The Relationship  

E-Print Network [OSTI]

" FL Water Law Regulated Riparianism "Heavy" Admin Water Law ? #12;Comprehensive Water Resource Study Supply a. Water Allocation ­ Withdrawal Permit Program b. Water Storage & Delivery c. Interbasin TransferThe Essentials for GA Water Planning The Relationship Between the Proposed GA State Comprehensive

Rosemond, Amy Daum

158

Fl YO Co -op E athea lectric  

E-Print Network [OSTI]

are based on a false premise that the cost and usage pattern for energy in the Pacific Northwest should and Energy Efficiency The High Level indicator of "Regional Electricity Use per Person vs. US Average" shouldFl YO Co -op E athea lectric Community...Integrity...Reliability 2510 U.S. Highway 2 East

159

ARIZONA STATE UNIVERSITY STETSON UNIVERSITY Phoenix, AZ Deland, FL  

E-Print Network [OSTI]

English Literature English BOWLING GREEN STATE UNIVERSITY Bowling Green, OH SYRACUSE UNIVERSITY IndustrialARIZONA STATE UNIVERSITY STETSON UNIVERSITY Phoenix, AZ Deland, FL Interdisciplinary Studies Leadership FLORIDA STATE UNIVERSITY Instructional Systems Design Tallahassee, FL Interdisciplinary Studies

Wu, Shin-Tson

160

FUPWG Meeting Agenda - Destin, FL | Department of Energy  

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

Destin, FL FUPWG Meeting Agenda - Destin, FL Going coastal for energy efficiency. FUPWG. April 15-16, 2008, Destin, Florida Gulf Power: A Southern Company FEMP logo April 15-16,...

Note: This page contains sample records for the topic "al fl 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.


161

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 (OSTI)

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

162

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 (OSTI)

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

163

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

164

Epitaxial growth of 100-?m thick M-type hexaferrite crystals on wide bandgap semiconductor GaN/Al{sub 2}O{sub 3} substrates  

SciTech Connect (OSTI)

Thick barium hexaferrite BaFe{sub 12}O{sub 19} (BaM) films having thicknesses of ?100??m were epitaxially grown on GaN/Al{sub 2}O{sub 3} substrates from a molten-salt solution by vaporizing the solvent. X-ray diffraction measurement verified the growth of BaM (001) textured growth of thick films. Saturation magnetization, 4?M{sub s}, was measured for as-grown films to be 4.6 0.2 kG and ferromagnetic resonance measurements revealed a microwave linewidth of ?100?Oe at X-band. Scanning electron microscopy indicated clear hexagonal crystals distributed on the semiconductor substrate. These results demonstrate feasibility of growing M-type hexaferrite crystal films on wide bandgap semiconductor substrates by using a simple powder melting method. It also presents a potential pathway for the integration of ferrite microwave passive devices with active semiconductor circuit elements creating system-on-a-wafer architectures.

Hu, Bolin; Su, Zhijuan; Bennett, Steve; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

2014-05-07T23:59:59.000Z

165

Comparison of the properties of AlGaInN light-emitting diode chips of vertical and flip-chip design using silicon as the a submount  

SciTech Connect (OSTI)

Vertical and flip-chip light-emitting diode (LED) chips are compared from the viewpoint of the behavior of current spreading in the active region and the distribution of local temperatures and thermal resistances of chips. AlGaInN LED chips of vertical design are fabricated using Si as a submount and LED flipchips were fabricated with the removal of a sapphire substrate. The latter are also mounted on a Si submount. The active regions of both chips are identical and are about 1 mm{sup 2} in size. It is shown that both the emittance of the crystal surface in the visible range and the distribution of local temperatures estimated from radiation in the infrared region are more uniform in crystals of vertical design. Heat removal from flip-chips is insufficient in regions of the n contact, which do not possess good thermal contact with the submount. As a result, the total thermal resistances between the p-n junction and the submount both for the vertical chips and for flip-chips are approximately 1 K/W. The total area of the flip-chips exceeds that of the vertical design chips by a factor of 1.4.

Markov, L. K., E-mail: l.markov@mail.ioffe.ru; Smirnova, I. P.; Pavlyuchenko, A. S. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Kukushkin, M. V.; Vasil'eva, E. D. [ZAO Innovation 'Tetis' (Russian Federation); Chernyakov, A. E. [Russian Academy of Sciences, Science-and-Technology Microelectronics Center (Russian Federation); Usikov, A. S. [De Core Nanosemiconductors Ltd. (India)

2013-03-15T23:59:59.000Z

166

Vision FL LLC | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia:FAQ < RAPID Jump to:Seadov PtyInformation UCOpenVerona,HamptonVinland,InformationVirydFL LLC Jump to:

167

US SoAtl FL Site Consumption  

Gasoline and Diesel Fuel Update (EIA)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) " ,"ClickPipelines About U.S. NaturalA. Michael SchaalNovember 26,8,CoalThousandIL SiteMidAtl PANE MA SiteFL

168

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 (OSTI)

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

169

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 (OSTI)

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

170

GaSb molecular beam epitaxial growth on p-InP(001) and passivation with in situ deposited Al{sub 2}O{sub 3} gate oxide  

SciTech Connect (OSTI)

The integration of high carrier mobility materials into future CMOS generations is presently being studied in order to increase drive current capability and to decrease power consumption in future generation CMOS devices. If III-V materials are the candidates of choice for n-type channel devices, antimonide-based semiconductors present high hole mobility and could be used for p-type channel devices. In this work we first demonstrate the heteroepitaxy of fully relaxed GaSb epilayers on InP(001) substrates. In a second part, the properties of the Al{sub 2}O{sub 3}/GaSb interface have been studied by in situ deposition of an Al{sub 2}O{sub 3} high-{kappa} gate dielectric. The interface is abrupt without any substantial interfacial layer, and is characterized by high conduction and valence band offsets. Finally, MOS capacitors show well-behaved C-V with relatively low D{sub it} along the bandgap, these results point out an efficient electrical passivation of the Al{sub 2}O{sub 3}/GaSb interface.

Merckling, C.; Brammertz, G.; Hoffmann, T. Y.; Caymax, M.; Dekoster, J. [Interuniversity Microelectronics Center (IMEC vzw), Kapeldreef 75, 3001, Leuven (Belgium); Sun, X. [Katholieke Universiteit Leuven, Celestijnelaan 200D, 3001, Leuven (Belgium); Department of Electrical Engineering, Yale University, New Haven, Connecticut 06520-8284 (United States); Alian, A.; Heyns, M. [Interuniversity Microelectronics Center (IMEC vzw), Kapeldreef 75, 3001, Leuven (Belgium); Katholieke Universiteit Leuven, Celestijnelaan 200D, 3001, Leuven (Belgium); Afanas'ev, V. V. [Katholieke Universiteit Leuven, Celestijnelaan 200D, 3001, Leuven (Belgium)

2011-04-01T23:59:59.000Z

171

The crystal and magnetic structures of LaCa{sub 2}Fe{sub 3-x}M{sub x}O{sub 8} (M=Al, Ga, In)  

SciTech Connect (OSTI)

LaCa{sub 2}Fe{sub 3}O{sub 8} (A{sub 3}B{sub 3}O{sub 8}) is an example of a layered structure in that it consists of pairs of octahedral, perovskite-like layers alternating with a single tetrahedral layer. This work explores the doping of non-magnetic group 13 elements, M=Al, Ga and In, onto the B-site of LaCa{sub 2}Fe{sub 3-x}M{sub x}O{sub 8} as a function of x. The structural and magnetic effects are examined using a combination of neutron and X-ray diffraction. Solubility limits are established. It is found that for M=Ga the solubility limit occurs between x=1.0 and x=1.25, for the synthesis conditions used, while there is evidence for low (x<0.25) but non-zero substitution of Al. Structural refinements at x=1 suggest that Ga prefers neither the tetrahedral nor octahedral sites. The magnetic structure of LaCa{sub 2}Fe{sub 2}GaO{sub 8} has been examined using neutron diffraction at 3.2 K and room temperature. At low temperature the staggered moment per Fe{sup 3+} is 3.8(1){mu}{sub B} in LaCa{sub 2}Fe{sub 3}O{sub 8} and 4.8(1){mu}{sub B} in LaCa{sub 2}Fe{sub 2}GaO{sub 8}. The magnetic space group (P{sub 2b}2{sub 1} Prime ma Prime ) and moment direction (along c) does not appear to change with Ga substitution. - Graphical abstract: Solubility limits for group 13 elements in LaCa{sub 2}Fe{sub 3}O{sub 8}. Highlights: Black-Right-Pointing-Pointer Solubility limits for group 13 elements in LaCa{sub 2}Fe{sub 3}O{sub 8} are determined. Black-Right-Pointing-Pointer Evolution of the magnetic structure with temperature and doping is explored using neutron scattering. Black-Right-Pointing-Pointer The magnetic space group is quoted as P{sub 2b}2{sub 1}'ma' and the staggered moments are obtained for LaCa{sub 2}Fe{sub 3}O{sub 8} and LaCa{sub 2}Fe{sub 2}GaO{sub 8}.

Goossens, D.J., E-mail: goossens@rsc.anu.edu.au [Research School of Chemistry, Australian National University, Canberra 0200 (Australia); Henderson, L.S.F.; Trevena, S. [School of Engineering, Australian National University, Canberra 0200 (Australia)] [School of Engineering, Australian National University, Canberra 0200 (Australia); Hudspeth, J.M. [Research School of Physics and Engineering, Australian National University, Canberra 0200 (Australia)] [Research School of Physics and Engineering, Australian National University, Canberra 0200 (Australia); Avdeev, M.; Hester, J.R. [The Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia)] [The Bragg Institute, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia)

2012-12-15T23:59:59.000Z

172

Sub-250?nm low-threshold deep-ultraviolet AlGaN-based heterostructure laser employing HfO{sub 2}/SiO{sub 2} dielectric mirrors  

SciTech Connect (OSTI)

We report a sub-250-nm, optically pumped, deep-ultraviolet laser using an Al{sub x}Ga{sub 1?x}N-based multi-quantum-well structure grown on a bulk Al-polar c-plane AlN substrate. TE-polarization-dominant lasing action was observed at room temperature with a threshold pumping power density of 250?kW/cm{sup 2}. After employing high-reflectivity SiO{sub 2}/HfO{sub 2} dielectric mirrors on both facets, the threshold pumping power density was further reduced to 180?kW/cm{sup 2}. The internal loss and threshold modal gain can be calculated as 2?cm{sup ?1} and 10.9?cm{sup ?1}, respectively.

Kao, Tsung-Ting; Liu, Yuh-Shiuan; Mahbub Satter, Md.; Li, Xiao-Hang; Lochner, Zachary; Douglas Yoder, P.; Detchprohm, Theeradetch; Dupuis, Russell D.; Shen, Shyh-Chiang, E-mail: shyh.shen@ece.gatech.edu; Ryou, Jae-Hyun [School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States)] [School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Dr. NW, Atlanta, Georgia 30332-0250 (United States); Fischer, Alec M.; Wei, Yong; Xie, Hongen; Ponce, Fernando A. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)] [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)

2013-11-18T23:59:59.000Z

173

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

174

150W.UniversityBlvd. Melbourne,FL32901  

E-Print Network [OSTI]

150W.UniversityBlvd. Melbourne,FL32901 321-674-8000 NickAbruzzini Junior,Ocean Engineering JanelleBoisvert Junior,Ocean Engineering KatieDobek Junior, Ocean Engineering Anthony Tedeschi Junior,Ocean Engineering

Wood, Stephen L.

175

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

176

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

E-Print Network [OSTI]

/Thomas Swan close-coupled showerhead cold-wall MOCVD system. The buffer epilayers of GaAs were grown on 2 in for these interfaces. In addition, when designing an in situ MOCVD process, the typical TMA/H2O is incompatible

177

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

178

Electrical and structural characteristics of metamorphic In{sub 0.38}Al{sub 0.62}As/In{sub 0.37}Ga{sub 0.63}As/In{sub 0.38}Al{sub 0.62}As HEMT nanoheterostructures  

SciTech Connect (OSTI)

The influence of the metamorphic buffer design and epitaxial growth conditions on the electrical and structural characteristics of metamorphic In{sub 0.38}Al{sub 0.62}As/In{sub 0.37}Ga{sub 0.63}As/In{sub 0.38}Al{sub 0.62}As high electron mobility transistor (MHEMT) nanoheterostructures has been investigated. The samples were grown on GaAs(100) substrates by molecular beam epitaxy. The active regions of the nanoheterostructures are identical, while the metamorphic buffer In{sub x}Al{sub 1-x}As is formed with a linear or stepwise (by {Delta}{sub x} = 0.05) increase in the indium content over depth. It is found that MHEMT nanoheterostructures with a step metamorphic buffer have fewer defects and possess higher values of two-dimensional electron gas mobility at T = 77 K. The structures of the active region and metamorphic buffer have been thoroughly studied by transmission electron microscopy. It is shown that the relaxation of metamorphic buffer in the heterostructures under consideration is accompanied by the formation of structural defects of the following types: dislocations, microtwins, stacking faults, and wurtzite phase inclusions several nanometers in size.

Galiev, G. B., E-mail: s_s_e_r_p@mail.ru; Klimov, E. A.; Klochkov, A. N.; Maltsev, P. P.; Pushkarev, S. S. [Russian Academy of Sciences, Institute of Ultrahigh Frequency Semiconductor Electronics (Russian Federation)] [Russian Academy of Sciences, Institute of Ultrahigh Frequency Semiconductor Electronics (Russian Federation); Zhigalina, O. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Imamov, R. M., E-mail: imamov@ns.crys.ras.ru [Russian Academy of Sciences, Institute of Ultrahigh Frequency Semiconductor Electronics (Russian Federation); Kuskova, A. N.; Khmelenin, D. N. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2013-11-15T23:59:59.000Z

179

Defect kinetics in spinels: Long-time simulations of MgAl{sub 2}O{sub 4}, MgGa{sub 2}O{sub 4}, and MgIn{sub 2}O{sub 4}  

SciTech Connect (OSTI)

Building upon work in which we examined defect production and stability in spinels, we now turn to defect kinetics. Using temperature accelerated dynamics (TAD), we characterize the kinetics of defects in three spinel oxides: magnesium aluminate MgAl{sub 2}O{sub 4}, magnesium gallate MgGa{sub 2}O{sub 4}, and magnesium indate MgIn{sub 2}O{sub 4}. These materials have varying tendencies to disorder on the cation sublattices. In order to understand chemical composition effects, we first examine defect kinetics in perfectly ordered, or normal, spinels, focusing on point defects on each sublattice. We then examine the role that cation disorder has on defect mobility. Using TAD, we find that disorder creates local environments which strongly trap point defects, effectively reducing their mobility. We explore the consequences of this trapping via kinetic Monte Carlo (KMC) simulations on the oxygen vacancy (V{sub O}) in MgGa{sub 2}O{sub 4}, finding that V{sub O} mobility is directly related to the degree of inversion in the system.

Uberuaga, B. P.; Voter, A. F.; Sickafus, K. E. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Bacorisen, D.; Smith, Roger [Department of Mathematical Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom); Ball, J. A.; Grimes, R. W. [Department of Materials, Imperial College, Prince Consort Road, London SW7 2BP (United Kingdom)

2007-03-01T23:59:59.000Z

180

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 (OSTI)

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; Bchner, 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

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181

CPDD 2011 Annual Meeting June 22, 2011 Hollywood, FL  

E-Print Network [OSTI]

Individualized Sequences of Health Interventions Using SMART Design Technology to Develop an Adaptive and When CPDD 2011 Annual Meeting June 22, 2011 Hollywood, FL 2. Clinical Setting Address Barriers to Care Improve maternal and infant outcomes Conduct clinical research to generate new knowledge to improve

Murphy, Susan A.

182

Synthesis and structural characterization of the ternary Zintl phases AE{sub 3}Al{sub 2}Pn{sub 4} and AE{sub 3}Ga{sub 2}Pn{sub 4} (AE=Ca, Sr, Ba, Eu; Pn=P, As)  

SciTech Connect (OSTI)

Ten new ternary phosphides and arsenides with empirical formulae AE{sub 3}Al{sub 2}Pn{sub 4} and AE{sub 3}Ga{sub 2}Pn{sub 4} (AE=Ca, Sr, Ba, Eu; Pn=P, As) have been synthesized using molten Ga, Al, and Pb fluxes. They have been structurally characterized by single-crystal and powder X-ray diffraction to form with two different structures-Ca{sub 3}Al{sub 2}P{sub 4}, Sr{sub 3}Al{sub 2}As{sub 4}, Eu{sub 3}Al{sub 2}P{sub 4}, Eu{sub 3}Al{sub 2}As{sub 4}, Ca{sub 3}Ga{sub 2}P{sub 4}, Sr{sub 3}Ga{sub 2}P{sub 4}, Sr{sub 3}Ga{sub 2}As{sub 4}, and Eu{sub 3}Ga{sub 2}As{sub 4} crystallize with the Ca{sub 3}Al{sub 2}As{sub 4} structure type (space group C2/c, Z=4); Ba{sub 3}Al{sub 2}P{sub 4} and Ba{sub 3}Al{sub 2}As{sub 4} adopt the Na{sub 3}Fe{sub 2}S{sub 4} structure type (space group Pnma, Z=4). The polyanions in both structures are made up of TrPn{sub 4} tetrahedra, which share common corners and edges to form {sup 2}{sub {infinity}}[TrPn{sub 2}]{sub 3-} layers in the phases with the Ca{sub 3}Al{sub 2}As{sub 4} structure, and {sup 1}{sub {infinity}}[TrPn{sub 2}]{sub 3-} chains in Ba{sub 3}Al{sub 2}P{sub 4} and Ba{sub 3}Al{sub 2}As{sub 4} with the Na{sub 3}Fe{sub 2}S{sub 4} structure type. The valence electron count for all of these compounds follows the Zintl-Klemm rules. Electronic band structure calculations confirm them to be semiconductors. - Graphical abstract: AE{sub 3}Al{sub 2}Pn{sub 4} and AE{sub 3}Ga{sub 2}Pn{sub 4} (AE=Ca, Sr, Ba, Eu; Pn=P, As) crystallize in two different structures-Ca{sub 3}Al{sub 2}P{sub 4}, Sr{sub 3}Al{sub 2}As{sub 4}, Eu{sub 3}Al{sub 2}P{sub 4}, Eu{sub 3}Al{sub 2}As{sub 4}, Ca{sub 3}Ga{sub 2}P{sub 4}, Sr{sub 3}Ga{sub 2}P{sub 4}, Sr{sub 3}Ga{sub 2}As{sub 4}, and Eu{sub 3}Ga{sub 2}As{sub 4}, are isotypic with the previously reported Ca{sub 3}Al{sub 2}As{sub 4} (space group C2/c (No. 15)), while Ba{sub 3}Al{sub 2}P{sub 4} and Ba{sub 3}Al{sub 2}As{sub 4} adopt a different structure known for Na{sub 3}Fe{sub 2}S{sub 4} (space group Pnma (No. 62). The polyanions in both structures are made up of TrPn{sub 4} tetrahedra, which by sharing common corners and edges, form {sup 2}{sub {infinity}}[TrPn{sub 2}]{sub 3-}layers in the former and {sup 1}{sub {infinity}}[TrPn{sub 2}]{sub 3-} chains in Ba{sub 3}Al{sub 2}P{sub 4} and Ba{sub 3}Al{sub 2}As{sub 4}. Highlights: Black-Right-Pointing-Pointer AE{sub 3}Ga{sub 2}Pn{sub 4} (AE=Ca, Sr, Ba, Eu; Pn=P, As) are new ternary pnictides. Black-Right-Pointing-Pointer Ba{sub 3}Al{sub 2}P{sub 4} and Ba{sub 3}Al{sub 2}As{sub 4} adopt the Na{sub 3}Fe{sub 2}S{sub 4} structure type. Black-Right-Pointing-Pointer The Sr- and Ca-compounds crystallize with the Ca{sub 3}Al{sub 2}As{sub 4} structure type. Black-Right-Pointing-Pointer The valence electron count for all title compounds follows the Zintl-Klemm rules.

He, Hua; Tyson, Chauntae; Saito, Maia [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States); Bobev, Svilen, E-mail: bobev@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716 (United States)

2012-04-15T23:59:59.000Z

183

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 (OSTI)

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

184

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

185

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

186

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 (OSTI)

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

187

DOE - Office of Legacy Management -- Armour Fertilizer Works - FL 01  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou are here Home » SitesNJFertilizer Works - FL 01

188

City of Quincy, FL Smart Grid Project | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublic Utilities Address: 160Benin:Energy Nebraska (UtilityGeorgiaArkansas References: EIA Form EIA-861Quincy, FL

189

Sandia National Laboratories: HeFl Flow Loop  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -theErik Spoerke SSLS Exhibit at ExploraGlobal SandiaVermontFacilityHeFl Flow Loop

190

E-Print Network 3.0 - aurigae fl lyrae Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Search Sample search results for: aurigae fl lyrae Page: << < 1 2 3 4 5 > >> 1 Astronomy C Tiger Invitational February 20, 2010 Summary: Astronomy C Tiger Invitational...

191

Thermoelectric figure of merit of (In0.53Ga0.47As)0.8(In0.52Al0.48As)0.2 III-V semiconductor alloys Je-Hyeong Bahk,1 Zhixi Bian,2 Mona Zebarjadi,2 Joshua M. O. Zide,3 Hong Lu,1,4 Dongyan Xu,5 Joseph P. Feser,5  

E-Print Network [OSTI]

, 73.50.Lw, 73.61.Ey I. INTRODUCTION Seeking a better thermoelectric material for efficient thermal The efficiency of a thermoelectric material is directly linked to the dimensionless thermoelectric figureThermoelectric figure of merit of (In0.53Ga0.47As)0.8(In0.52Al0.48As)0.2 III-V semiconductor alloys

192

Characterisation of Ga-coated and Ga-brazed aluminium  

SciTech Connect (OSTI)

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

193

Lattice-matched epitaxial GaInAsSb/GaSb thermophotovoltaic devices  

SciTech Connect (OSTI)

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

194

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

195

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

196

GA-AL-SC | Department of Energy  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of Energy Power.pdf11-161-LNG | Department of Energy Freeport LNGEnergy Research |G-8 Energy

197

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 (OSTI)

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

198

Mechanism of Nitric Oxide Reactivity and Fluorescence Enhancement of the NO-Specific Probe CuFL1  

E-Print Network [OSTI]

The mechanism of the reaction of CuFL1 (FL1 = 2-{2-chloro-6-hydroxy-5-[(2-methylquinolin-8-ylamino)methyl]-3-oxo-3H-xanthen-9-yl}benzoic acid) with nitric oxide (NO) to form the N-nitrosated product FL1-NO in buffered ...

McQuade, Lindsey E.

199

als geschichtliches und: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Verbindungen mit Lithium 18 2.1.3 Elektrolyte Hoffmann, Rolf 5 Wachstum und Realstruktur von epitaktischen (Al,Ga)N-Schichten. Open Access...

200

als erstmanifestation einer: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

durch Photoeffekt mit zirkular polarisiertem Licht an einem GaAs-Kristall erzeugt Pir. Als Lichtquelle wird ein Lasersystem verwendet, das linear polarisiertes Licht...

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

als instrument einer: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

durch Photoeffekt mit zirkular polarisiertem Licht an einem GaAs-Kristall erzeugt Pir. Als Lichtquelle wird ein Lasersystem verwendet, das linear polarisiertes Licht...

202

als folge einer: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

durch Photoeffekt mit zirkular polarisiertem Licht an einem GaAs-Kristall erzeugt Pir. Als Lichtquelle wird ein Lasersystem verwendet, das linear polarisiertes Licht...

203

p-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas  

SciTech Connect (OSTI)

Here, GaN/Al{sub x}Ga{sub 1-x}N heterostructures with a graded AlN composition, completely lacking external p-doping, are designed and grown using metal-organic-chemical-vapour deposition (MOCVD) system to realize three-dimensional hole gas (3DHG). The existence of the 3DHG is confirmed by capacitance-voltage measurements. Based on this design, a p-doping-free InGaN/GaN light-emitting diode (LED) driven by the 3DHG is proposed and grown using MOCVD. The electroluminescence, which is attributed to the radiative recombination of injected electrons and holes in InGaN/GaN quantum wells, is observed from the fabricated p-doping-free devices. These results suggest that the 3DHG can be an alternative hole source for InGaN/GaN LEDs besides common Mg dopants.

Zhang, Zi-Hui; Tiam Tan, Swee; Kyaw, Zabu; Liu, Wei; Ji, Yun; Ju, Zhengang; Zhang, Xueliang [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore) [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Wei Sun, Xiao, E-mail: EXWSUN@ntu.edu.sg [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electronics and Electrical Engineering, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Volkan Demir, Hilmi, E-mail: VOLKAN@stanfordalumni.org [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electrical and Electronics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey); Department of Physics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey)

2013-12-23T23:59:59.000Z

204

Collector-up light-emitting charge injection transistors in n-lnGaAs/lnAIAs/ plllnGaAs and n-lnGaAs/lnP/p-InGaAs heterostructures  

E-Print Network [OSTI]

Collector-up light-emitting charge injection transistors in n-lnGaAs/lnAIAs/ plllnGaAs and n (Received 23 November 1992; accepted for publication 4 March 1993) The realization of collector-up light for the collector stripe definition. Electrons, injected over the wide-gap heterostructure barrier (InAlAs or In

Luryi, Serge

205

Ph. 234 --Topics in Theoretical Physics lectures by Dr. f:l. Gell-r.Iann  

E-Print Network [OSTI]

j Ph. 234 -- Topics in Theoretical Physics lectures by Dr. f:l. Gell-r.Iann notes by \\'Jilliam G by Dr. Murray Gell-Ma.nn; vritten by... William G. 'Hagner. September 30, 1958 We shall first reviev

Martin, Alain

206

ASME 2008 Summer Heat transfer Conference August 10-14, 2008, Jacksonville, FL., USA  

E-Print Network [OSTI]

ASME 2008 Summer Heat transfer Conference August 10-14, 2008, Jacksonville, FL., USA HT2008, University of Victoria Victoria, BC , V8W 2Y2, Canada ABSTRACT Accurate information on the temperature eld

Bahrami, Majid

207

International Journal of Foundations of Computer Science fl World Scientific Publishing Company  

E-Print Network [OSTI]

International Journal of Foundations of Computer Science c fl World Scientific Publishing Company Science, University of Idaho Moscow, Idaho 83844­1010, USA and MOSHE DROR MIS Department, University

Krings, Axel W.

208

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

SciTech Connect (OSTI)

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

209

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

. investigated the diffusion behavior of Mg in GaN and AlGaN layers during MOCVD growth.13) Their study concluded... that no signifi- cant diffusionsegregation behavior...

210

Nano-scale luminescence characterization of individual InGaN/GaN quantum wells stacked in a microcavity using scanning transmission electron microscope cathodoluminescence  

SciTech Connect (OSTI)

Using cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope at liquid helium temperatures, the optical and structural properties of a 62 InGaN/GaN multiple quantum well embedded in an AlInN/GaN based microcavity are investigated at the nanometer scale. We are able to spatially resolve a spectral redshift between the individual quantum wells towards the surface. Cathodoluminescence spectral linescans allow directly visualizing the critical layer thickness in the quantum well stack resulting in the onset of plastic relaxation of the strained InGaN/GaN system.

Schmidt, Gordon, E-mail: Gordon.Schmidt@ovgu.de; Mller, Marcus; Veit, Peter; Bertram, Frank; Christen, Jrgen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, 39106 Magdeburg (Germany); Glauser, Marlene; Carlin, Jean-Franois; Cosendey, Gatien; Butt, Raphal; Grandjean, Nicolas [Institute of Condensed Matter Physics, cole Polytechnique Fdrale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2014-07-21T23:59:59.000Z

211

Rare Earth ? N = N* fs fGHZ fp nH fl  

E-Print Network [OSTI]

Rare Earth ? #12;N to date N = N* fs fGHZ fp nH fl ·N* = 4 x 1011 ·fs = 0.2 ·fGHZ = 0.1 ·fp = 0.8 ·nH = 2 ·fl = 1.0 N = 1.3 x 1010 #12;The Goldilocks Effect Earth is "Just Right" Yes, life on Earth has adapted to Earth, but ... Earth has just the right mass to be ·Tectonically-active ·Retain

Walter, Frederick M.

212

Gallium Arsenide (GaAs) EDWARD D. PALIK  

E-Print Network [OSTI]

constants of pure (semi-insulating) GaAs are derived from a number of papers including the far-infrared at. [4]; the near-IR work of Pikhtin and Yas'kov [5]; the calorim- etry work of Christensen et al. [6 reflection work of Philipp and Ehrenreich [9]; and the synchrotron transmission work of Cardona et al. [10

Pulfrey, David L.

213

GaAsSb-based heterojunction tunnel diodes for tandem solar cell interconnects  

SciTech Connect (OSTI)

We report a new approach to tunnel junctions that employs a pseudomorphic GaAsSb layer to obtain a band alignment at a InGaAs or InAlAs p-n junction favorable for forward bias tunneling. Since the majority of the band offset between GaAsSb and InGaAs or InAlAs is in the valence band, when an GaAsSb layer is placed at an InGaAs or InAlAs p-n junction the tunneling distance is reduced and the tunneling current is increased. For all doping levels studied, the presence of the GaAsSb-layer enhanced the forward tunneling characteristics. In fact, in a InGaAs/GaAsSb tunnel diode a peak tunneling current sufficient for a 1000 sun intercell interconnect was achieved with p = 1.5{times}l0{sup 18} cm{sup -3} while a similarly doped all-InGaAs diode was rectifying. This approach affords a new degree of freedom in designing tunnel junctions for tandem solar cell interconnects. Previously only doping levels could be varied to control the tunneling properties. Our approach relaxes the doping requirements by employing a GaAsSb-based heterojunction.

Zolper, J.C.; Klem, J.F.; Plut, T.A.; Tigges, C.P.

1995-01-01T23:59:59.000Z

214

THE FLORIDA STATE UNIVERSITY * THE GRADUATE SCHOOL * 314 WESTCOTT * TALLAHASSEE, FL. 32306-1410 Florida State University  

E-Print Network [OSTI]

THE FLORIDA STATE UNIVERSITY * THE GRADUATE SCHOOL * 314 WESTCOTT * TALLAHASSEE, FL. 32306 to gs-drg@admin.fsu.edu: Florida State University The Graduate School 314 Westcott Building Tallahassee be carried over. #12;THE FLORIDA STATE UNIVERSITY * THE GRADUATE SCHOOL * 314 WESTCOTT * TALLAHASSEE, FL

215

THE FLORIDA STATE UNIVERSITY * THE GRADUATE SCHOOL * 408 WESTCOTT * TALLAHASSEE, FL. 32306-1410 Florida State University  

E-Print Network [OSTI]

THE FLORIDA STATE UNIVERSITY * THE GRADUATE SCHOOL * 408 WESTCOTT * TALLAHASSEE, FL. 32306 Fellowship ­ Fall 2011 408 Westcott Building Tallahassee, Florida 32306-1410 Deadline The application STATE UNIVERSITY * THE GRADUATE SCHOOL * 408 WESTCOTT * TALLAHASSEE, FL. 32306-1410 Fall 2011 ***FOUR

Bowers, Philip L.

216

INTRODUCTION Since Zadeh [20] introduced Fuzzy Sets, many discussions have taken place whether Fuzzy Logic (FL) deserves a place  

E-Print Network [OSTI]

Fuzzy Logic (FL) deserves a place in control theory. Three properties speak in favour of FL control larger than the true maximal input for a system, Fuzzy Logic Controllers (FLC) by nature restrict A j x µ j x ( ) NLQ THEORY BASED STABILITY ANALYSIS OF SISO FUZZY LOGIC CONTROLLERS J?RGEN VAN GORP

217

Machine Learning, ??, 1--6 (1994) fl 1994 Kluwer Academic Publishers, Boston. Manufactured in The Netherlands.  

E-Print Network [OSTI]

Machine Learning, ??, 1--6 (1994) c fl 1994 Kluwer Academic Publishers, Boston. Manufactured in The Netherlands. Book Review: C4.5: Programs for Machine Learning by J. Ross Quinlan. Morgan Kaufmann Publishers are among the most well known and widely used of all machine learning methods. Among decision tree

Salzberg, Steven

218

FL47CH15-Goldstein ARI 25 November 2014 9:45 Green Algae as Model  

E-Print Network [OSTI]

FL47CH15-Goldstein ARI 25 November 2014 9:45 Green Algae as Model Organisms for Biological Fluid green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model of flagellar synchronization. Green algae are well suited to the study of such problems because of their range

Goldstein, Raymond E.

219

Deciduous Fruit Options for North FL Landscapes by Terry DelValle, Urban Horticulture Extension Agent  

E-Print Network [OSTI]

Deciduous Fruit Options for North FL Landscapes by Terry DelValle, Urban Horticulture Extension your homework first. Site Selection: Here is a list of criteria. Fruit require an open sunny spot/variety will get at matur- ity. Selecting Varieties: Select varieties adapted to our area. Deciduous fruit, also

Watson, Craig A.

220

Department of Ocean and Mechanical Engineering 777 Glades Road, Boca Raton, FL 33431  

E-Print Network [OSTI]

Department of Ocean and Mechanical Engineering 777 Glades Road, Boca Raton, FL 33431 561.297.3430, fax 561.297.3885 SeaTech ­ The Institute for Ocean & Systems Engineering 101 North Beach Road, Dania of Ocean and Mechanical Engineering at Florida Atlantic University is pleased to announce fellowship

Fernandez, Eduardo

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

DOE Zero Energy Ready Home Case Study, e2Homes, Winterpark, FL, Custom Homes  

Broader source: Energy.gov [DOE]

Case study of a DOE Zero Energy Ready Home in Winter Park, FL that scored HERS 57 without PV or HERS -7 with PV. This 4,305 ft2 custom home has autoclaved aerated concrete walls, a sealed attic with R-20 spray foam, and ductless mini-split heat pumps.

222

ARTM E. MASUNOV 12424 Research Parkway, Suite 400, Orlando, FL 32826 USA  

E-Print Network [OSTI]

Professor, NanoScience Technology Center, Department of Chemistry, Department of Physics & Florida Solar Energy Center, University of Central Florida, FL (UCF) 2002-2005: Postdoctoral Research Associate, Russia (with Prof. P. M. Zorkii) #12;Dr. Artëm E. Masunov, UCF NSTC 2 Professional Societies: - American

Kik, Pieter

223

25th AIAA Applied Aerodynamics Conference June 2528, 2007/Miami, FL  

E-Print Network [OSTI]

25th AIAA Applied Aerodynamics Conference June 25­28, 2007/Miami, FL Validation Study of Aerodynamic Analysis Tools for Design Optimization of Helicopter Rotors Seongim Choi , Juan J. Alonso , Edwin current aerodynamic analysis tools in predicting the unsteady flow field generated by helicopter rotors

Alonso, Juan J.

224

St. Petersburg, FL: Vehicle Use of Recycled Natural Gas Derived from Wastewater Biosolids  

Broader source: Energy.gov [DOE]

Breakout Session 3AConversion Technologies III: Energy from Our WasteWill we Be Rich in Fuel or Knee Deep in Trash by 2025? St. Petersburg, FL: Vehicle Use of Recycled Natural Gas Derived from Wastewater Biosolids William Eleazer, Supervising Engineer, Brown and Caldwell

225

Clear@, , D HThe model is --eqn 12-14 in Bjornstad et al.  

E-Print Network [OSTI]

Clear@, , D HThe model is -- eqn 12-14 in Bjornstad et al. N0 HtL = Exp HL S HtL => N0 HtL = Exp HL + x2 + x3 x2 x1 + x2 + x3 x3 x1 + x2 + x3 0 y { zzzzzzzzzzzzzzzzzzzzz Bjornstad&al.nb 1 #12;H in Bjornstad et al. NOTE: the below is cast in terms of angular frequencies, w: w = 2 fL Id := Identity

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 (OSTI)

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

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

228

Ultra High p-doping Material Research for GaN Based Light Emitters  

SciTech Connect (OSTI)

The main goal of the Project is to investigate doping mechanisms in p-type GaN and AlGaN and controllably fabricate ultra high doped p-GaN materials and epitaxial structures. Highly doped p-type GaN-based materials with low electrical resistivity and abrupt doping profiles are of great importance for efficient light emitters for solid state lighting (SSL) applications. Cost-effective hydride vapor phase epitaxial (HVPE) technology was proposed to investigate and develop p-GaN materials for SSL. High p-type doping is required to improve (i) carrier injection efficiency in light emitting p-n junctions that will result in increasing of light emitting efficiency, (ii) current spreading in light emitting structures that will improve external quantum efficiency, and (iii) parameters of Ohmic contacts to reduce operating voltage and tolerate higher forward currents needed for the high output power operation of light emitters. Highly doped p-type GaN layers and AlGaN/GaN heterostructures with low electrical resistivity will lead to novel device and contact metallization designs for high-power high efficiency GaN-based light emitters. Overall, highly doped p-GaN is a key element to develop light emitting devices for the DOE SSL program. The project was focused on material research for highly doped p-type GaN materials and device structures for applications in high performance light emitters for general illumination P-GaN and p-AlGaN layers and multi-layer structures were grown by HVPE and investigated in terms of surface morphology and structure, doping concentrations and profiles, optical, electrical, and structural properties. Tasks of the project were successfully accomplished. Highly doped GaN materials with p-type conductivity were fabricated. As-grown GaN layers had concentration N{sub a}-N{sub d} as high as 3 x 10{sup 19} cm{sup -3}. Mechanisms of doping were investigated and results of material studies were reported at several International conferences providing better understanding of p-type GaN formation for Solid State Lighting community. Grown p-type GaN layers were used as substrates for blue and green InGaN-based LEDs made by HVPE technology at TDI. These results proved proposed technical approach and facilitate fabrication of highly conductive p-GaN materials by low-cost HVPE technology for solid state lighting applications. TDI has started the commercialization of p-GaN epitaxial materials.

Vladimir Dmitriev

2007-06-30T23:59:59.000Z

229

Ga nanoparticle-enhanced photoluminescence of GaAs  

SciTech Connect (OSTI)

We have examined the influence of surface Ga nanoparticles (NPs) on the enhancement of GaAs photoluminescence (PL) efficiency. We have utilized off-normal focused-ion-beam irradiation of GaAs surfaces to fabricate close-packed Ga NP arrays. The enhancement in PL efficiency is inversely proportional to the Ga NP diameter. The maximum PL enhancement occurs for the Ga NP diameter predicted to maximize the incident electromagnetic (EM) field enhancement. The PL enhancement is driven by the surface plasmon resonance (SPR)-induced enhancement of the incident EM field which overwhelms the SPR-induced suppression of the light emission.

Kang, M.; Al-Heji, A. A.; Jeon, S.; Wu, J. H. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Lee, J.-E.; Saucer, T. W.; Zhao, L.; Sih, V. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States); Katzenstein, A. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Eckerd College, St. Petersburg, Florida 33711-4744 (United States); Sofferman, D. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Adelphi University, Garden City, New York 11530-0701 (United States); Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

2013-09-02T23:59:59.000Z

230

Materials physics and device development for improved efficiency of GaN HEMT high power amplifiers.  

SciTech Connect (OSTI)

GaN-based microwave power amplifiers have been identified as critical components in Sandia's next generation micro-Synthetic-Aperture-Radar (SAR) operating at X-band and Ku-band (10-18 GHz). To miniaturize SAR, GaN-based amplifiers are necessary to replace bulky traveling wave tubes. Specifically, for micro-SAR development, highly reliable GaN high electron mobility transistors (HEMTs), which have delivered a factor of 10 times improvement in power performance compared to GaAs, need to be developed. Despite the great promise of GaN HEMTs, problems associated with nitride materials growth currently limit gain, linearity, power-added-efficiency, reproducibility, and reliability. These material quality issues are primarily due to heteroepitaxial growth of GaN on lattice mismatched substrates. Because SiC provides the best lattice match and thermal conductivity, SiC is currently the substrate of choice for GaN-based microwave amplifiers. Obviously for GaN-based HEMTs to fully realize their tremendous promise, several challenges related to GaN heteroepitaxy on SiC must be solved. For this LDRD, we conducted a concerted effort to resolve materials issues through in-depth research on GaN/AlGaN growth on SiC. Repeatable growth processes were developed which enabled basic studies of these device layers as well as full fabrication of microwave amplifiers. Detailed studies of the GaN and AlGaN growth of SiC were conducted and techniques to measure the structural and electrical properties of the layers were developed. Problems that limit device performance were investigated, including electron traps, dislocations, the quality of semi-insulating GaN, the GaN/AlGaN interface roughness, and surface pinning of the AlGaN gate. Surface charge was reduced by developing silicon nitride passivation. Constant feedback between material properties, physical understanding, and device performance enabled rapid progress which eventually led to the successful fabrication of state of the art HEMT transistors and amplifiers.

Kurtz, Steven Ross; Follstaedt, David Martin; Wright, Alan Francis; Baca, Albert G.; Briggs, Ronald D.; Provencio, Paula Polyak; Missert, Nancy A.; Allerman, Andrew Alan; Marsh, Phil F.; Koleske, Daniel David; Lee, Stephen Roger; Shul, Randy John; Seager, Carleton Hoover; Tigges, Christopher P.

2005-12-01T23:59:59.000Z

231

Bulk modulus and specific heat of B-site doped (La{sub 0.3}Pr{sub 0.7}){sub 0.65}Ca{sub 0.35}Mn{sub 1?x}B{sub x}O{sub 3} (B=Fe, Cr, Ru, Al, Ga)  

SciTech Connect (OSTI)

Specific heat (C{sub p}) thermal expansion (?) and Bulk modulus (B{sub T}) of lightly doped Rare Earth manganites (La{sub 0.3}Pr{sub 0.7}){sub 0.65}Ca{sub 0.35}Mn{sub 1?x}B{sub x}O{sub 3} (B{sup 3+}?=?Fe{sup 3+},Cr{sup 3+},Ga{sup 3+},Al{sup 3+},Ru4+); (0.3

Srivastava, Archana, E-mail: archanasaran01@gmail.com [Department of Physics, Sri Sathya Sai College for Women, Bhopal-462024 (India); Thakur, Rasna; Gaur, N. K. [Department of Physics, Barkatullah University, Bhopal-462026 (India)

2014-04-24T23:59:59.000Z

232

GaAs-based high temperature electrically pumped polariton laser  

SciTech Connect (OSTI)

Strong coupling effects and polariton lasing are observed at 155?K with an edge-emitting GaAs-based microcavity diode with a single Al{sub 0.31}Ga{sub 0.69}As/Al{sub 0.41}Ga{sub 0.59}As quantum well as the emitter. The threshold for polariton lasing is observed at 90?A/cm{sup 2}, accompanied by a reduction of the emission linewidth to 0.85?meV and a blueshift of the emission wavelength by 0.89?meV. Polariton lasing is confirmed by the observation of a polariton population redistribution in momentum space and spatial coherence. Conventional photon lasing is recorded in the same device at higher pump powers.

Baten, Md Zunaid; Bhattacharya, Pallab, E-mail: pkb@eecs.umich.edu; Frost, Thomas; Deshpande, Saniya; Das, Ayan [Center for Photonic and Multiscale Nanomaterials, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Lubyshev, Dimitri; Fastenau, Joel M.; Liu, Amy W. K. [IQE, Inc., 119 Technology Drive, Bethlehem, Pennsylvania 18015 (United States)

2014-06-09T23:59:59.000Z

233

8798_FL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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234

DOE - Office of Legacy Management -- University of Miami - FL 0-01  

Office of Legacy Management (LM)

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235

DOE - Office of Legacy Management -- Virginia-Carolina Chemical Corp - FL  

Office of Legacy Management (LM)

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236

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

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 NoPublicIDAPowerPlantSitingConstruction.pdfNotify98.pdf Jump to: navigation,storage plan reviewformP2.pdfFL.pdf Jump

237

ALS Visitors  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

238

Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology  

SciTech Connect (OSTI)

This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, [approximately] 1 [times] 10[sup 5] cm[sup [minus]5], as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 [times]10[sup 7] cm[sup [minus]2]. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

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

1993-04-01T23:59:59.000Z

239

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

240

Investigation of the GaN-on-GaAs interface for vertical power device applications  

SciTech Connect (OSTI)

GaN layers were grown onto (111) GaAs by molecular beam epitaxy. Minimal band offset between the conduction bands for GaN and GaAs materials has been suggested in the literature raising the possibility of using GaN-on-GaAs for vertical power device applications. I-V and C-V measurements of the GaN/GaAs heterostructures however yielded a rectifying junction, even when both sides of the junction were heavily doped with an n-type dopant. Transmission electron microscopy analysis further confirmed the challenge in creating a GaN/GaAs Ohmic interface by showing a large density of dislocations in the GaN layer and suggesting roughening of the GaN/GaAs interface due to etching of the GaAs by the nitrogen plasma, diffusion of nitrogen or melting of Ga into the GaAs substrate.

Mreke, Janina, E-mail: janina.moereke@bristol.ac.uk; Uren, Michael J.; Kuball, Martin [H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Novikov, Sergei V.; Foxon, C. Thomas [Department of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hosseini Vajargah, Shahrzad; Wallis, David J.; Humphreys, Colin J. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Haigh, Sarah J. [Super STEM Laboratory, STFC Daresbury Campus, Keckwick Lane, Daresbury WA4 4AD (United Kingdom); School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Al-Khalidi, Abdullah; Wasige, Edward; Thayne, Iain [School of Engineering, University of Glasgow, Rankine Bldg, Oakfield Avenue, Glasgow G12 8LT (United Kingdom)

2014-07-07T23:59:59.000Z

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

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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

242

Photoluminescence study of the 1.047 eV emission in GaN K. Pressela)  

E-Print Network [OSTI]

GaN/ AlGaN blue green light emitting diode, which has a much higher quantum efficiency than the SiC blue light emitting diode, became possible.2 Presently the wide bandgap semi- conductor GaN is intensively. Especially the 1.19 eV is very intense. Thus one can think of developing a light emitting diode in the near

Nabben, Reinhard

243

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

244

Sandia National Laboratories: AlGaAs LEDs  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared0Energy Advanced Nuclear Energy TheASCProducts Sandia

245

Influence of GaAs surface termination on GaSb/GaAs quantum dot structure and band offsets  

SciTech Connect (OSTI)

We have investigated the influence of GaAs surface termination on the nanoscale structure and band offsets of GaSb/GaAs quantum dots (QDs) grown by molecular-beam epitaxy. Transmission electron microscopy reveals both coherent and semi-coherent clusters, as well as misfit dislocations, independent of surface termination. Cross-sectional scanning tunneling microscopy and spectroscopy reveal clustered GaSb QDs with type I band offsets at the GaSb/GaAs interfaces. We discuss the relative influences of strain and QD clustering on the band offsets at GaSb/GaAs interfaces.

Zech, E. S.; Chang, A. S.; Martin, A. J.; Canniff, J. C.; Millunchick, J. M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Lin, Y. H. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)

2013-08-19T23:59:59.000Z

246

Machine Learning, 30, 241--273 (1998) fl 1998 Kluwer Academic Publishers, Boston. Manufactured in The Netherlands.  

E-Print Network [OSTI]

Machine Learning, 30, 241--273 (1998) c fl 1998 Kluwer Academic Publishers, Boston. Manufactured of a machine­aided knowledge discovery process within the general area of drug design. Within drug design study reported in this paper supports four general lessons for machine learning and knowledge discovery

Page Jr., C. David

247

NIF-0607-13692.ppt NIF Town Hall Meeting, June 16, 2007 1 Title page -APS, Orlando, FL, November 13,  

E-Print Network [OSTI]

NIF-0607-13692.ppt NIF Town Hall Meeting, June 16, 2007 1 Title page - APS, Orlando, FL, November 13, 2007 This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 Fusion Power Associates Oak Ridge, Tn

248

Proceedings of the US Hydrographic Conference, Tampa, FL, 25-28 Apr 2011 THE PORT OF NORFOLK PROJECT  

E-Print Network [OSTI]

Proceedings of the US Hydrographic Conference, Tampa, FL, 25-28 Apr 2011 1 THE PORT OF NORFOLK for the Port of Norfolk Project are to explore viable methods of improvement with respect to both the process intuitive fashion, or providing it in a format that is inherently more useful. The Port of Norfolk Project

New Hampshire, University of

249

ALS@20  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home|PhysicsGasandArgonneALS in the News ALS

250

ALS Spectrum  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience4AJ01) (See95TI07)Operations DuringALS DoctoralALSSpectroscopyALS

251

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.

252

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

253

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

SciTech Connect (OSTI)

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

254

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

255

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

256

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"

257

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.

258

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

259

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

SciTech Connect (OSTI)

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

260

The use of short-period InGaN/GaN superlattices in blue-region light-emitting diodes  

SciTech Connect (OSTI)

Optical and light-emitting diode structures with an active InGaN region containing short-period InGaN/GaN superlattices are studied. It is shown that short-period superlattices are thin two-dimensional layers with a relatively low In content that contain inclusions with a high In content 1-3 nm thick. Inclusions manifest themselves from the point of view of optical properties as a nonuniform array of quantum dots involved in a residual quantum well. The use of short-period superlattices in light-emitting diode structures allows one to decrease the concentration of nonradiative centers, as well as to increase the injection of carriers in the active region due to an increase in the effective height of the AlGaN barrier, which in general leads to an increase in the quantum efficiency of light-emitting diodes.

Sizov, V. S., E-mail: vsizov@mail.ioffe.ru; Tsatsulnikov, A. F.; Sakharov, A. V.; Lundin, W. V.; Zavarin, E. E.; Cherkashin, N. A. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Hytch, M. J. [National Center for Scientific Research (CNRS), Center for Material Elaboration and Structural Studies (CEMES) (France); Nikolaev, A. E. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Mintairov, A. M.; He Yan; Merz, J. L. [University of Notre Dame, EE Department (United States)

2010-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "al fl 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.


261

AL. I  

Office of Legacy Management (LM)

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262

ALS Visitors  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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263

ALS Visitors  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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264

Industry @ ALS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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265

ALS Spectrum  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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266

ALS Spectrum  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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267

Comparison of Chloroflexus aurantiacus strain J-10-fl proteomes of cells grown chemoheterotrophically and photoheterotrophically  

SciTech Connect (OSTI)

Chloroflexus aurantiacus J-10-fl is a thermophilic green bacterium, a filamentous anoxygenic phototroph, and the model organism of the phylum Chloroflexi. We applied high-throughput, liquid chromatography-mass spectrometry in a global quantitative proteomics investigation of C. aurantiacus cells grown under oxic (chemoorganoheterotrophically) and anoxic (photoorganoheterotrophically) redox states. Our global analysis identified 13,524 high-confidence peptides that matched to 1,286 annotated proteins, 242 of which were either uniquely identified or significantly increased in abundance under anoxic culture conditions. Fifty-three of the 242 proteins are previously characterized photosynthesis-related proteins, including chlorosome proteins, proteins involved in the bacteriochlorophyll biosynthesis, 3-hydroxypropionate (3-OHP) CO2 fixation pathway, and components of electron transport chains. The remaining 190 proteins have not previously been reported. Of these, five proteins were found to be encoded by genes from a novel operon and observed only in photoheterotrophically grown cells. These proteins candidates may prove useful in further deciphering the phototrophic physiology of C. aurantiacus and other filamentous anoxygenic phototrophs.

Cao, Li; Bryant, Donald A.; Schepmoes, Athena A.; Vogl, Kajetan; Smith, Richard D.; Lipton, Mary S.; Callister, Stephen J.

2012-01-17T23:59:59.000Z

268

Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes  

SciTech Connect (OSTI)

We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

Verma, Jai; Kandaswamy, Prem Kumar; Protasenko, Vladimir; Verma, Amit; Grace Xing, Huili; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)] [Department of Electrical Engineering, University of Notre Dame, Indiana 46556 (United States)

2013-01-28T23:59:59.000Z

269

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

SciTech Connect (OSTI)

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

270

SITN Regional Outreach Map  

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

Carolina Solar Center at North Carolina State University www.ncsc.ncsu.edumajestcindex.php Raleigh, NC Dr. Pam Carpenter pamcarpenter@ncsu.edu Southeast AL * AR * FL * GA KY *...

271

" Million Housing Units, Final...  

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

U.S.1 (millions)",,"Total South Atlantic" ,,"Total South",,,,,"DC, DE, MD, WV",,,,"AL, KY, MS",,,"AR, LA, OK" "Appliances",,,,"VA","GA","FL",,"NC, SC",,"TN",,,"TX" "Total...

272

" Million Housing Units, Final...  

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

U.S.1 (millions)",,"Total South Atlantic" ,,"Total South",,,,,"DC, DE, MD, WV",,,,"AL, KY, MS",,,"AR, LA, OK" "Televisions",,,,"VA","GA","FL",,"NC, SC",,"TN",,,"TX" "Total...

273

" Million Housing Units, Final...  

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

U.S.1 (millions)",,"Total South Atlantic" ,,"Total South",,,,,"DC, DE, MD, WV",,,,"AL, KY, MS",,,"AR, LA, OK" "Fuels Used and End Uses",,,,"VA","GA","FL",,"NC,...

274

" Million Housing Units, Final...  

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

U.S.1 (millions)",,"Total South Atlantic" ,,"Total South",,,,,"DC, DE, MD, WV",,,,"AL, KY, MS",,,"AR, LA, OK" "Household Demographics",,,,"VA","GA","FL",,"NC,...

275

Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)  

SciTech Connect (OSTI)

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

276

GA Solar | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartmentAUDIT REPORTOpen EnergyBoard" form. To create aGA SNC Solar Jump to:GA-Solar

277

GaN-Ready Aluminum Nitride Substrates for Cost-Effective, Very Low Dislocation Density III-Nitride LED's  

SciTech Connect (OSTI)

The objective of this project was to develop and then demonstrate the efficacy of a costeffective approach for a low defect density substrate on which AlInGaN LEDs can be fabricated. The efficacy of this GaN-ready substrate would then be tested by growing high efficiency, long lifetime InxGa1-xN blue LEDs. The approach used to meet the project objectives was to start with low dislocation density AlN single-crystal substrates and grow graded AlxGa1-xN layers on top. Pseudomorphic AlxGa1-xN epitaxial layers grown on bulk AlN substrates were used to fabricate light emitting diodes and demonstrate better device performance as a result of the low defect density in these layers when benched marked against state-of-the-art LEDs fabricated on sapphire substrates. The pseudomorphic LEDs showed excellent output powers compared to similar wavelength devices grown on sapphire substrates, with lifetimes exceeding 10,000 hours (which was the longest time that could reliably be estimated). In addition, high internal quantum efficiencies were demonstrated at high driving current densities even though the external quantum efficiencies were low due to poor photon extraction. Unfortunately, these pseudomorphic LEDs require high Al content so they emit in the ultraviolet. Sapphire based LEDs typically have threading dislocation densities (TDD) > 108 cm-2 while the pseudomorphic LEDs have TDD ? 105 cm-2. The resulting TDD, when grading the AlxGa1-xN layer all the way to pure GaN to produce a GaN-ready substrate, has varied between the mid 108 down to the 106 cm-2. These inconsistencies are not well understood. Finally, an approach to improve the LED structures on AlN substrates for light extraction efficiency was developed by thinning and roughening the substrate.

Sandra Schujman; Leo Schowalter

2010-10-15T23:59:59.000Z

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

Modeling single family housing recovery after Hurricane Andrew in Miami-Dade County, FL  

E-Print Network [OSTI]

, their recovery model is criticized for its inaccurate assumption of the homogeneous and linear nature of the recovery process (Berke & Beatley, 1992; 15 Berke et al., 1993; Quanrantelli, 1989). In fact, these four recovery stages can take place out...

Zhang, Yang

2009-06-02T23:59:59.000Z

280

Native point defects in GaSb  

SciTech Connect (OSTI)

We have applied positron annihilation spectroscopy to study native point defects in Te-doped n-type and nominally undoped p-type GaSb single crystals. The results show that the dominant vacancy defect trapping positrons in bulk GaSb is the gallium monovacancy. The temperature dependence of the average positron lifetime in both p- and n-type GaSb indicates that negative ion type defects with no associated open volume compete with the Ga vacancies. Based on comparison with theoretical predictions, these negative ions are identified as Ga antisites. The concentrations of these negatively charged defects exceed the Ga vacancy concentrations nearly by an order of magnitude. We conclude that the Ga antisite is the native defect responsible for p-type conductivity in GaSb single crystals.

Kujala, J.; Segercrantz, N.; Tuomisto, F.; Slotte, J. [Department of Applied Physics, Aalto University School of Science, P.O. Box 14100, FI-00076 AALTO (Finland)

2014-10-14T23:59:59.000Z

Note: This page contains sample records for the topic "al fl ga" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

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

SciTech Connect (OSTI)

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

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

2005-11-01T23:59:59.000Z

282

Beta decay of Ga-62  

E-Print Network [OSTI]

from the ex- perimental ft value for a 01?01 b decay between analog states with the relation @3# 0556-2813/2003/68~1!/015501~6!/$20.00 68 015501- of 62Ga . Hardy, V. E. Mayes, R. G. Neilson, M. Sanchez-Vega, and R. E. Tribble y, College Station...

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

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 m, 60 min reaction 1 m, 25 min reaction 0

Firestone, Jeremy

285

Fractal Inspired Models of Quark and Gluon Distributions and Longitudinal Structure Function FL(x, Q2) at small x  

E-Print Network [OSTI]

In recent years, Fractal Inspired Models of quark and gluon densities at small x have been proposed. In this paper, we investigate longitudinal structure function F-L (x, Q2) within this approach. We make predictions using the QCD based approximate relation between the longitudinal structure function and the gluon density. As the Altarelli-Martinelli equation for the longitudinal structure function cannot be applied to Model I due to the presence of a singularity in the Bjorken x-space we consider Model II only. The qualitative feature of the prediction of Model II is found to be compatible with the QCD expectation.

Akbari Jahan; D. K. Choudhury

2010-12-30T23:59:59.000Z

286

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.

287

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

SciTech Connect (OSTI)

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

288

Structure, transport and thermal properties of UCoGa  

SciTech Connect (OSTI)

By means of neutron powder diffraction, we find that UCoGa crystallizes in the hexagonal ZrNiAl structure and orders ferromagnetically at low temperatures with magnetic moments stacked along the c axis. The magnetic-ordering temperature is reflected in anomalies in the temperature dependencies of the electrical resistivity and the specific heat at Tc = 47 K. Furthermore, the strong anisotropy in the electrical resistivity for i {parallel} c and i {perpendicular} c indicates a significant contribution of the magnetic anisotropy to the electrical resistivity.

Purwanto, A.; Robinson, R.A. [Los Alamos National Lab., NM (United States); Prokes, K. [Amsterdam Univ. (Netherlands). Van der Waals Lab.] [and others

1994-04-01T23:59:59.000Z

289

InGaAsN/GaAs heterojunction for multi-junction solar cells  

DOE Patents [OSTI]

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

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

2001-01-01T23:59:59.000Z

290

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

291

Low-cost, high-efficiency solar cells utilizing GaAs-on-Si technology. Annual subcontract report, 1 August 1991--31 July 1992  

SciTech Connect (OSTI)

This report describes work to develop technology to deposit GaAs on Si using a nucleation layer of atomic-layer-epitaxy-grown GaAs or AlAs on Si. This ensures two-dimensional nucleation and should lead to fewer defects in the final GaAs layer. As an alternative, we also developed technology for depositing GaAs on sawtooth-patterned Si. Preliminary studies showed that this material can have a very low defect density, {approximately} 1 {times} 10{sup 5} cm{sup {minus}5}, as opposed to our conventionally grown GaAs on SL which has a typical defect density of over 1 {times}10{sup 7} cm{sup {minus}2}. Using these two now methods of GaAs-on-Si material growth, we made solar cells that are expected to show higher efficiencies than those of previous cells.

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

1993-04-01T23:59:59.000Z

292

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

SciTech Connect (OSTI)

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

293

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

SciTech Connect (OSTI)

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

294

Siemens Pittsburgh, PA Novelis Corporation Atlanta, GA  

E-Print Network [OSTI]

Industrial Design ­ Shanghai, China Eaton Corporation ­ Pittsburgh, PA CMU, CTTEC ­ PittsburghSiemens ­ Pittsburgh, PA Novelis Corporation ­ Atlanta, GA Expense

McGaughey, Alan

295

Spontaneous emission in GaN/InGaN photonic crystal nanopillars  

E-Print Network [OSTI]

. Sigalas, "InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal, "III-nitride blue and ultraviolet photonic crystal light emitting diodes," Appl. Phys. Lett. 84, 466, and H. Benisty, "Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution

Boyer, Edmond

296

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

SciTech Connect (OSTI)

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

297

Zarillo, G. A., and Brehin, F. G. A. 2007. Hydrodynamic and Morphologic Modeling at Sebastian Inlet, FL. Proceedings Coastal Sediments '07 Conference, ASCE Press, Reston,  

E-Print Network [OSTI]

Inlet, FL. Proceedings Coastal Sediments '07 Conference, ASCE Press, Reston, VA, 1297-1310. HYDRODYNAMIC Modeling System (CMS) to investigate the morphological response to time varying forcing, sediment texture evolution of tidal inlet shoals is an important management tool, since they control sediment budgets. Inlet

US Army Corps of Engineers

298

Embracing and Empowering Women to Serve Central Florida PO BOX 2895 Orlando FL 32802 ! wecOrlando.com ! facebook.com/wecOrlando ! scholarships@wecOrlando.com  

E-Print Network [OSTI]

Orlando.com ! facebook.com/wecOrlando ! scholarships@wecOrlando.com 42nd ANNUAL WOMEN'S ACHIEVEMENT AWARDS EVENT Monday Orlando FL 32802 ! wecOrlando.com ! facebook.com/wecOrlando ! scholarships@wecOrlando.com All information 32802 ! wecOrlando.com ! facebook.com/wecOrlando ! scholarships@wecOrlando.com Please provide three (3

Van Stryland, Eric

299

FUPWG Meeting Agenda - Atlanta, GA | Department of Energy  

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

Atlanta, GA FUPWG Meeting Agenda - Atlanta, GA 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,...

300

TEM Characterization of InAs/GaAs Quantum Dots Capped by a GaSb/GaAs Layer  

SciTech Connect (OSTI)

It is well known that there is intense interest in expanding the usable wavelength for electronic devices. This is one of the reasons to study new self-assembled semiconductor nanostructures. Telecommunication applications use InGaAsP/InP emitting at 1.3 and 1.55 m. Research efforts are dedicated to develop GaAs technology in order to achieve emission at the same range as InP, so GaAs could be used for optical fibre communications. Ga(As)Sb on InAs/GaAs quantum dots (QDs) is a promising nanostructure to be used in telecommunications. The introduction of antimony during or after the QDs growth is an effective solution to obtain a red shift in the emission wavelength, even at room temperature.

Beltran, AM [Universidad de Cadiz, Spain; Ben, Teresa [Universidad de Cadiz, Spain; Sanchez, AM [Universidad de Cadiz, Spain; Sales Lerida, David [ORNL; Chisholm, Matthew F [ORNL; Varela del Arco, Maria [ORNL; Pennycook, Stephen J [ORNL; Galindo, Pedro [Universidad de Cadiz, Spain; Ripalda, JM [Instituto de Microelectronica de Madrid (CNM, CSIC); Molina Rubio, Sergio I [ORNL

2008-01-01T23:59:59.000Z

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

Strong light-matter coupling in ultrathin double dielectric mirror GaN microcavities  

SciTech Connect (OSTI)

Strong light-matter coupling is demonstrated at low temperature in an ultrathin GaN microcavity fabricated using two silica/zirconia Bragg mirrors, in addition to a three-period epitaxial (Al,Ga)N mirror serving as an etch stop and assuring good quality of the overgrown GaN. The {lambda}/2 cavity is grown by molecular beam epitaxy on a Si substrate. Analysis of angle-resolved data reveal key features of the strong coupling regime in both reflectivity and transmission spectra at 5 K: anticrossing with a normal mode splitting of 43{+-}2 meV and 56{+-}2 meV for reflectivity and transmission, respectively, and narrowing of the lower polariton linewidth near resonance.

Bejtka, K.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); CRHEA-CNRS, Rue Bernard Gregory, Parc Sophia Antipolis, 06560 Valbonne (France); Reveret, F.; Vasson, A.; Leymarie, J. [LASMEA, UMR 6602 UBP/CNRS, 24 Avenue des Landais, F-63177 Aubiere Cedex (France); Edwards, P. R. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Sellers, I. R.; Duboz, J. Y.; Leroux, M.; Semond, F. [CRHEA-CNRS, Rue Bernard Gregory, Parc Sophia Antipolis, 06560 Valbonne (France)

2008-06-16T23:59:59.000Z

302

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

SciTech Connect (OSTI)

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.; Lng, 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); Korpijrvi, V.-M.; Polojrvi, 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

303

Epitaxial Growth of GaN-based LEDs on Simple Sacrificial Substrates  

SciTech Connect (OSTI)

The objective of this project is to produce alternative substrate technologies for GaN-based LEDs by developing an ALD interlayer of Al{sub 2}O{sub 3} on sacrificial substrates such as ZnO and Si. A sacrificial substrate is used for device growth that can easily be removed using a wet chemical etchant leaving only the thin GaN epi-layer. After substrate removal, the GaN LED chip can then be mounted in several different ways to a metal heat sink/reflector and light extraction techniques can then be applied to the chip and compared for performance. Success in this work will lead to high efficiency LED devices with a simple low cost fabrication method and high product yield as stated by DOE goals for its solid state lighting portfolio.

Ian Ferguson; Chris Summers

2009-12-31T23:59:59.000Z

304

Charge tuning in [111] grown GaAs droplet quantum dots  

SciTech Connect (OSTI)

We demonstrate charge tuning in strain free GaAs/AlGaAs quantum dots (QDs) grown by droplet epitaxy on a GaAs(111)A substrate. Application of a bias voltage allows the controlled charging of the QDs from ?3|e| to +2|e|. The resulting changes in QD emission energy and exciton fine-structure are recorded in micro-photoluminescence experiments at T?=?4?K. We uncover the existence of excited valence and conduction states, in addition to the s-shell-like ground state. We record a second series of emission lines about 25?meV above the charged exciton emission coming from excited charged excitons. For these excited interband transitions, a negative diamagnetic shift of large amplitude is uncovered in longitudinal magnetic fields.

Bouet, L.; Vidal, M.; Marie, X.; Amand, T.; Wang, G.; Urbaszek, B. [INSA-CNRS-UPS, LPCNO, Universit de Toulouse, 135 Ave. Rangueil, 31077 Toulouse (France); Mano, T.; Ha, N.; Kuroda, T.; Sakoda, K. [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan); Durnev, M. V.; Glazov, M. M.; Ivchenko, E. L. [Ioffe Physical-Technical Institute RAS, 194021 St.-Petersburg (Russian Federation)

2014-08-25T23:59:59.000Z

305

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

SciTech Connect (OSTI)

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

306

-and -Coordinated Al in AlC2 . A Combined  

E-Print Network [OSTI]

- and -Coordinated Al in AlC2 - and AlCSi- . A Combined Photoelectron Spectroscopy and ab Initio the structure and chemical bonding in AlC2 - and AlCSi-. AlC2 - was found to have a C2V structure whereas AlCSi- was found to be almost linear, thus establishing -coordination of Al in AlC2 - and -coordination in Al

Simons, Jack

307

Structural and optical properties of InGaNGaN nanowire heterostructures grown by molecular beam epitaxy  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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 Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Gotschke, T. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Stoica, T. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany); Calarco, R. [Institute of Bio- and Nanosystems (IBN-1), Research Centre Jlich 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 Jlich GmbH and JARA-FIT Fundamentals of Future Information Technology (Germany)

2011-01-07T23:59:59.000Z

308

Complete genome sequence of Syntrophobotulus glycolicus type strain (FlGlyRT)  

SciTech Connect (OSTI)

Syntrophobotulus glycolicus Friedrich et al. 1996 is currently the only member of the genus Syntrophobotulus within the family Peptococcaceae. The species is of interest because of its isolated phylogenetic location in the genome-sequenced fraction of tree of life. When grown in pure culture with glyoxylate as carbon source the organism utilizes glyoxylate through fermentative oxidation, whereas, when grown in syntrophic co-culture with homoacetogenic or methanogenic bacteria, it is able to oxidize glycolate to carbon dioxide and hydrogen. No other organic or inorganic carbon source is utilized by S. glycolicus. The subdivision of the family Peptococcaceae into genera does not reflect the natural relationships, particularly re- garding the genera most closely related to Syntrophobotulus. Both Desulfotomaculum and Pelotomaculum are paraphyletic assemblages, and the taxonomic classification is in signifi- cant conflict with the 16S rRNA data. S. glycolicus is already the ninth member of the family Peptococcaceae with a completely sequenced and publicly available genome. The 3,406,739 bp long genome with its 3,370 protein-coding and 69 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

Han, Cliff [Los Alamos National Laboratory (LANL); Mwirichia, Romano [Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya; Chertkov, Olga [Los Alamos National Laboratory (LANL); Held, Brittany [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Hammon, Nancy [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Ovchinnikova, Galina [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Sikorski, Johannes [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute

2011-01-01T23:59:59.000Z

309

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

310

60nm collector InGaAs/InP Type-I DHBTs demonstrating 660 GHz f , BVCEO = 2.5V, and BVCBO = 2.7V  

E-Print Network [OSTI]

60nm collector InGaAs/InP Type-I DHBTs demonstrating 660 GHz f , BVCEO = 2.5V, and BVCBO = 2.7VGaAs base and a 60 nm InP collector containing an InGaAs/InAlAs superlattice grade. Devices employing a 400. The devices have been scaled vertically for reduced base and collector electron transit times, and the base-collector

Rodwell, Mark J. W.

311

Dependence of the ground-state transition energy versus optical pumping in GaAsSb/InGaAs/GaAs heterostructures  

SciTech Connect (OSTI)

In this work, we report on the time-resolved photoluminescence studies of a double quantum well In{sub 0.2}Ga{sub 0.8}As/GaAs{sub 0.8}Sb{sub 0.2}/GaAs heterostructure which, in contrast to the GaAsSb/GaAs structures, is expected to provide effective confinement of electrons due to additional InGaAs layer. The studies at 4.2?K have revealed a complicated nonmonotonic dependence of the ground-state transition energy on the concentration of nonequilibrium charge carriers in the quantum well. The effect observed in this work is important in terms of creating sources of radiation, including stimulated emission, on the basis of InGaAs/GaAsSb/GaAs structures.

Morozov, S. V.; Kryzhkov, D. I., E-mail: krizh@ipmras.ru; Aleshkin, V. Ya. [Institute for Physics of Microstructures, RAS, 603950 Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation); Yablonsky, A. N.; Krasilnik, Z. F. [Institute for Physics of Microstructures, RAS, 603950 Nizhny Novgorod (Russian Federation); Zvonkov, B. N.; Vikhrova, O. V. [Physical-Technical Research Institute, Lobachevsky State University of Nizhny Novgorod, 603950 Nizhny Novgorod (Russian Federation)

2014-01-13T23:59:59.000Z

312

Highly uniform, multi-stacked InGaAs/GaAs quantum dots embedded in a GaAs nanowire  

SciTech Connect (OSTI)

We demonstrate a highly uniform, dense stack of In{sub 0.22}Ga{sub 0.78}As/GaAs quantum dot (QD) structures in a single GaAs nanowire (NW). The size (and hence emission energy) of individual QD is tuned by careful control of the growth conditions based on a diffusion model of morphological evolution of NWs and optical characterization. By carefully tailoring the emission energies of individual QD, dot-to-dot inhomogeneous broadening of QD stacks in a single NW can be as narrow as 9.3?meV. This method provides huge advantages over traditional QD stack using a strain-induced Stranski-Krastanow growth scheme. We show that it is possible to fabricate up to 200 uniform QDs in single GaAs NWs using this growth technique without degradation of the photoluminescence intensity.

Tatebayashi, J., E-mail: tatebaya@iis.u-tokyo.ac.jp; Ota, Y. [NanoQUINE, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Ishida, S.; Nishioka, M.; Iwamoto, S.; Arakawa, Y. [NanoQUINE, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan); Institute of Industrial Science, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

2014-09-08T23:59:59.000Z

313

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 the electronic thermal con- ductivity of thermoelectric materials is proportional to their electrical Joshua M. O. Zide and Arthur C. Gossard Department of Materials, University of California, Santa Barbara

314

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

315

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

316

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

317

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

318

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

SciTech Connect (OSTI)

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

319

Under-gate defect formation in Ni-gate AlGaN/GaN high electron mobility transistors  

E-Print Network [OSTI]

energy loss spectroscopy [23]. In contrast, HEMTs utilizing a Pt liner layer did not show the same gate electrical contact to the 2DEG. However, when stressing occurs in O2 or air, the O2 present reacts

Florida, University of

320

GaAs/AlGaAs single quantum well p-i-n structures: A surface photovoltage study  

E-Print Network [OSTI]

size effects in low dimensional systems have been the subject of extensive experimental and theoretical- port of such low dimensional systems. Since their optical and electronic properties govern their photovoltaic behavior, the latter is strongly affected by the presence of a quantum well QW in the structure

Shapira, Yoram

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

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

322

InAsGaPInGaP high-temperature power Schottky rectifier and J. M. Woodall  

E-Print Network [OSTI]

C. Further improvement of the thermal stability is expected to be achieved by reducing the diffusion is thought to be due to strong covalent bonding at the InAs/GaP interface. The InAs/GaP heterointerface effectively blocks impurity diffusion. Since InGaP is superior to GaP for high-power applica- tions, as shown

Woodall, Jerry M.

323

Journal of Crystal Growth 298 (2007) 272275 Dislocation analysis in homoepitaxial GaInN/GaN light emitting  

E-Print Network [OSTI]

of GaInN/GaN-based light emitting diodes (LED) on quasi-bulk GaN with an atomically flat polished were much improved. The optical output power of the light emitting diode increased by more than one. Cathodoluminescence; A1. Threading dislocation density; A2. Homoepitaxial growth; B1. GaInN; B3. Light emitting diode

Wetzel, Christian M.

324

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

325

Strong light-matter coupling in bulk GaN-microcavities with double dielectric mirrors fabricated by two different methods  

SciTech Connect (OSTI)

Two routes for the fabrication of bulk GaN microcavities embedded between two dielectric mirrors are described, and the optical properties of the microcavities thus obtained are compared. In both cases, the GaN active layer is grown by molecular beam epitaxy on (111) Si, allowing use of selective etching to remove the substrate. In the first case, a three period Al{sub 0.2}Ga{sub 0.8}N/AlN Bragg mirror followed by a {lambda}/2 GaN cavity are grown directly on the Si. In the second case, a crack-free 2 {mu}m thick GaN layer is grown, and progressively thinned to a final thickness of {lambda}. Both devices work in the strong coupling regime at low temperature, as evidenced by angle-dependent reflectivity or transmission experiments. However, strong light-matter coupling in emission at room temperature is observed only for the second one. This is related to the poor optoelectronic quality of the active layer of the first device, due to its growth only 250 nm above the Si substrate and its related high defect density. The reflectivity spectra of the microcavities are well accounted for by using transfer matrix calculations.

Reveret, F.; Disseix, P.; Vasson, A.; Leymarie, J. [Clermont Universite, Universite Blaise Pascal, LASMEA, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, LASMEA, F-63177 Aubiere (France); Bejtka, K. [CRHEA-CNRS, Rue Bernard Gregory, Parc Sophia Antipolis, 06560 Valbonne (France); Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Edwards, P. R.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Chenot, S.; Sellers, I. R.; Duboz, J. Y.; Leroux, M.; Semond, F. [CRHEA-CNRS, Rue Bernard Gregory, Parc Sophia Antipolis, 06560 Valbonne (France)

2010-08-15T23:59:59.000Z

326

Polarization matching design of InGaN-based semi-polar quantum wellsA case study of (112{sup }2) orientation  

SciTech Connect (OSTI)

We present a theoretical study of the polarization engineering in semi-polar III-nitrides heterostructures. As a case study, we investigate the influence of GaN, AlGaN, and AlInN barrier material on the performance of semi-polar (112{sup }2) InGaN-based quantum wells (QWs) for blue (450?nm) and yellow (560?nm) emission. We show that the magnitude of the total built-in electric field across the QW can be controlled by the barrier material. Our results indicate that AlInN is a promising candidate to achieve (i) reduced wavelength shifts with increasing currents and (ii) strongly increased electron-hole wave function overlap, important for reduced optical recombination times.

Kozlowski, Grzegorz, E-mail: grzegorz.kozlowski@tyndall.ie; Schulz, Stefan; Corbett, Brian [Tyndall National Institute, Lee Maltings, Cork (Ireland)

2014-02-03T23:59:59.000Z

327

Charge Profiling of the p-AlGaN Electron Blocking Layer in AlGaInN Light Emitting Diode Structures  

E-Print Network [OSTI]

-layers. Placement, doping, and dimensions thereof are deemed critical to the stabilization of the injection-3 . A spacer layer of 20 ­ 100 nm separates the n-side and the quantum well region. Like the barrier

Wetzel, Christian M.

328

211 Westcott Building, 222 S. Copeland Avenue, P.O. Box 3061480, Tallahassee, FL 32306-1480 Telephone 850.644.6876, Fax 850.644.3375 http://fda.fsu.edu  

E-Print Network [OSTI]

211 Westcott Building, 222 S. Copeland Avenue, P.O. Box 3061480, Tallahassee, FL 32306 in the Office of the Vice President for Faculty Development and Advancement in Westcott 115 by Monday, October 7

Sura, Philip

329

408 Westcott Building, Florida State University, P.O. Box 3061410, Tallahassee, FL 32306-1410 Telephone 850.644.3501 Fax 850.644.2969 www.gradschool.fsu.edu  

E-Print Network [OSTI]

408 Westcott Building, Florida State University, P.O. Box 3061410, Tallahassee, FL 32306 Westcott. Student deadline to departments is February 1, 2011. Folders for all nominees are due

Bowers, Philip L.

330

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

331

Near-surface depletion of antimony during the growth of GaAsSb and GaAs/GaAsSb nanowires  

SciTech Connect (OSTI)

The near-surface reduction of the Sb mole fraction during the growth of GaAsSb nanowires (NWs) and GaAs NWs with GaAsSb inserts has been studied using quantitative high-angle annular dark field scanning transmission electron microscopy (STEM). A model for diffusion of Sb in the hexagonal NWs was developed and employed in combination with the quantitative STEM analysis. GaAsSb NWs grown by Ga-assisted molecular beam epitaxy (MBE) and GaAs/GaAsSb NWs grown by Ga- and Au-assisted MBE were investigated. At the high temperatures employed in the NW growth, As-Sb exchange at and outward diffusion of Sb towards the surface take place, resulting in reduction of the Sb concentration at and near the surface in the GaAsSb NWs and the GaAsSb inserts. In GaAsSb NWs, an increasing near-surface depletion of Sb was observed towards the bottom of the NW due to longer exposure to the As beam flux. In GaAsSb inserts, an increasing change in the Sb concentration profile was observed with increasing post-insert axial GaAs growth time, resulting from a combined effect of radial GaAs overgrowth and diffusion of Sb. The effect of growth temperature on the diffusion of Sb in the GaAsSb inserts was identified. The consequences of these findings for growth optimization and the optoelectronic properties of GaAsSb are discussed.

Kauko, H.; Helvoort, A. T. J. van, E-mail: a.helvoort@ntnu.no [Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim (Norway); Fimland, B. O.; Munshi, A. M. [Department of Electronics and Telecommunications, NTNU, Trondheim (Norway); Grieb, T.; Mller, K.; Rosenauer, A. [Institut fr Festkrperphysik, Universitt Bremen, Bremen (Germany)

2014-10-14T23:59:59.000Z

332

Nanoair-bridged lateral overgrowth of GaN on ordered nanoporous GaN template  

SciTech Connect (OSTI)

We report the growth of high-quality GaN epilayers on an ordered nanoporous GaN template by metalorganic chemical vapor deposition. The nanopores in GaN template were created by inductively coupled plasma etching using anodic aluminum oxide film as an etch mask. The average pore diameter and interpore distance is about 65 and 110 nm, respectively. Subsequent overgrowth of GaN first begins at the GaN crystallite surface between the pores, and then air-bridge-mediated lateral overgrowth leads to the formation of the continuous layer. Microphotoluminescence and micro-Raman measurements show improved optical properties and significant strain relaxation in the overgrown layer when compared to GaN layer of same thickness simultaneously grown on sapphire without any template. Similar to conventional epitaxial lateral overgrown GaN, such overgrown GaN on a nanopatterned surface would also serve as a template for the growth of ultraviolet-visible light-emitting III-nitride devices.

Wang, Y.D.; Zang, K.Y.; Chua, S.J.; Tripathy, S.; Chen, P.; Fonstad, C.G. [Singapore-MIT Alliance, E4-04-10, 4 Engineering Drive 3, Singapore 117576 (Singapore) and Centre for Optoelectronics, Department of Electrical and Computer Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602 (Singapore); Department of Electrical and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2005-12-19T23:59:59.000Z

333

Gallium surface diffusion on GaAs (001) surfaces measured by crystallization dynamics of Ga droplets  

SciTech Connect (OSTI)

We present accurate measurements of Ga cation surface diffusion on GaAs surfaces. The measurement method relies on atomic force microscopy measurement of the morphology of nanodisks that evolve, under group V supply, from nanoscale group III droplets, earlier deposited on the substrate surface. The dependence of the radius of such nano-droplets on crystallization conditions gives direct access to Ga diffusion length. We found an activation energy for Ga on GaAs(001) diffusion E{sub A}=1.310.15 eV, a diffusivity prefactor of D{sub 0}?=?0.53(2.11) cm{sup 2} s{sup ?1} that we compare with the values present in literature. The obtained results permit to better understand the fundamental physics governing the motion of group III adatoms on IIIV crystal surfaces and the fabrication of designable nanostructures.

Bietti, Sergio, E-mail: sergio.bietti@mater.unimib.it; Somaschini, Claudio; Esposito, Luca; Sanguinetti, Stefano [LNESS and Dipartimento di Scienza dei Materiali, Universit di Milano Bicocca, Via Cozzi 55, I20125 Milano (Italy); Fedorov, Alexey [LNESS and CNRIFN, via Anzani 42, I-22100 Como (Italy)

2014-09-21T23:59:59.000Z

334

Green cubic GaInN/GaN light-emitting diode on microstructured silicon (100)  

SciTech Connect (OSTI)

GaInN/GaN light-emitting diodes free of piezoelectric polarization were prepared on standard electronic-grade Si(100) substrates. Micro-stripes of GaN and GaInN/GaN quantum wells in the cubic crystal structure were grown on intersecting (111) planes of microscale V-grooved Si in metal-organic vapor phase epitaxy, covering over 50% of the wafer surface area. Crystal phases were identified in electron back-scattering diffraction. A cross-sectional analysis reveals a cubic structure virtually free of line defects. Electroluminescence over 20 to 100??A is found fixed at 487?nm (peak), 516?nm (dominant). Such structures therefore should allow higher efficiency, wavelength-stable light emitters throughout the visible spectrum.

Stark, Christoph J. M.; Detchprohm, Theeradetch; Wetzel, Christian, E-mail: wetzel@ieee.org [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Future Chips Constellation, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180 (United States); Lee, S. C.; Brueck, S. R. J. [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States)] [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States); Jiang, Y.-B. [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)] [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

2013-12-02T23:59:59.000Z

335

Monolithically Peltier-cooled vertical-cavity surface-emitting lasers Paul FL Berger, Niloy K. Dutta, Kent D. Choquette, Ghulam Hasnain, and Naresh Chand  

E-Print Network [OSTI]

GaAs laser. Also, in a monolithically integrated thermo- electric cooled InGaAsP/InP laser diode, Dutta et ~1 temperature of f 7.5 "C has been achieved using f 100 mA of thermoelectric cooler current. The observed" thermoelectric cooler, or a mono- lithically integrated thermoelectric cooler. Hava et ~1.~ ob- served a 2 "C

336

0.52eV Quaternary InGaAsSb Thermophotovoltaic Diode Technology  

SciTech Connect (OSTI)

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

337

Quantum confinement in GaP nanoclusters  

SciTech Connect (OSTI)

We have prepared GaP and GaAs nanoclusters from organometallic condensation reactions of E[Si(ChH{sub 3})3]3 (E = P, As) and GaCl{sub 3}. The size of the as synthesized clusters is 10 {Angstrom} to 15 {Angstrom}. Larger clusters of 20 {Angstrom} to 30 {Angstrom} size were obtained by thermal annealing of the as grown material. X-ray diffraction and transmission electron microscopy confirm the high crystalline quality. A lattice contraction of 6.7% could be seen for 10 {Angstrom} sized GaAs clusters. The clusters are nearly spherical in shape. Optical absorption spectra show a distinct line which can be assigned to the fundamental transition of the quantum confined electronic state. The measured blue shift, with respect to the GaP bulk absorption edge is 0.53 eV. As the cluster is smaller than the exciton radius, we can calculate the cluster size from this blue shift and obtain 20.2 {Angstrom}, consistent with the results from X-ray diffraction of 19.5 {Angstrom} for the same sample.

Laurich, B.K.; Smith, D.C.; Healy, M.D.

1994-06-01T23:59:59.000Z

338

Spectroscopy of AlAr and AlKr from 31 000 cm-1 to the ionization limit Scott A. Heidecke,@ Zhenwen Fu,b, John FL Colt,") and Michael D. Morse  

E-Print Network [OSTI]

speciessuch as glyoxal-Ar (Ref. 10) and s-tetrazine-acety- lene." In most cases, however, only one (or a few

Morse, Michael D.

339

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

340

Defect studies in low-temperature-grown GaAs  

SciTech Connect (OSTI)

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

Bliss, D.E.

1992-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "al fl 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.


341

Defect studies in low-temperature-grown GaAs  

SciTech Connect (OSTI)

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

342

FL J. Smith, Jr.  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$ EGcG ENERGY MEASUREMENTS;/:4,4 (; .369s

343

PMCI'Fl.  

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

not limited to: programmed lowering of thermostat settings, placement of timers on hot water heaters, installation of solar hot water systems. installation of efficient...

344

Strain-induced fundamental optical transition in (In,Ga)As/GaP quantum dots  

SciTech Connect (OSTI)

The nature of the ground optical transition in an (In,Ga)As/GaP quantum dot is thoroughly investigated through a million atoms supercell tight-binding simulation. Precise quantum dot morphology is deduced from previously reported scanning-tunneling-microscopy images. The strain field is calculated with the valence force field method and has a strong influence on the confinement potentials, principally, for the conduction band states. Indeed, the wavefunction of the ground electron state is spatially confined in the GaP matrix, close to the dot apex, in a large tensile strain region, having mainly Xz character. Photoluminescence experiments under hydrostatic pressure strongly support the theoretical conclusions.

Robert, C., E-mail: cedric.robert@insa-rennes.fr, E-mail: cedric.robert@tyndall.ie; Pedesseau, L.; Cornet, C.; Jancu, J.-M.; Even, J.; Durand, O. [Universit Europenne de Bretagne, INSA Rennes, France and CNRS, UMR 6082 Foton, 20 Avenue des Buttes de Cosmes, 35708 Rennes (France)] [Universit Europenne de Bretagne, INSA Rennes, France and CNRS, UMR 6082 Foton, 20 Avenue des Buttes de Cosmes, 35708 Rennes (France); Nestoklon, M. O. [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)] [Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Pereira da Silva, K. [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain) [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain); Departamento de Fsica, Universidade Federal do Cear, P.O. Box 6030, FortalezaCE, 60455-970 (Brazil); Alonso, M. I. [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain)] [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain); Goi, A. R. [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain) [ICMAB-CSIC, Campus UAB, 08193 Bellaterra (Spain); ICREA, Passeig Llus Companys 23, 08010 Barcelona (Spain); Turban, P. [Equipe de Physique des Surfaces et Interfaces, Institut de Physique de Rennes UMR UR1-CNRS 6251, Universit de Rennes 1, F-35042 Rennes Cedex (France)] [Equipe de Physique des Surfaces et Interfaces, Institut de Physique de Rennes UMR UR1-CNRS 6251, Universit de Rennes 1, F-35042 Rennes Cedex (France)

2014-01-06T23:59:59.000Z

345

Nucleation and Growth of GaN on GaAs (001) Substrates  

SciTech Connect (OSTI)

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

346

On strongly GA-convex functions and stochastic processes  

SciTech Connect (OSTI)

In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

Bekar, Nurgl Okur [Department of Statistics, Giresun University, Giresun (Turkey); Akdemir, Hande Gnay; ??can, ?mdat [Department of Mathematics, Giresun University, Giresun (Turkey)

2014-08-20T23:59:59.000Z

347

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

348

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

SciTech Connect (OSTI)

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

349

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

SciTech Connect (OSTI)

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

350

Accurate characterization and improvement of GaAs microstrip attenuation  

E-Print Network [OSTI]

Convergence. III. E. 6 Final Model. III. F Simulation Results for 100 um GaAs. . III. F. 1 On-GaAs Microstrip. III. I', 2 Suspended Microstrip Line . . . . 50 . . . . 51 . . . . 54 . . . . 56 . . . . 56 . . . 56 . . . . 64 64 . . . , 64 III. F. 3... Comparison Between On-GaAs and Suspcndcd Microstrip . . . 68 III. F. 4 Microstrip Inductance III. G EM Parameters in CAD Simulations . . III. H Simulation Results for 150 um GaAs. III. I Conclusions and Recommendations. IV RESEARCH ACCOMPLISHMENTS...

Carroll, James Mason

2012-06-07T23:59:59.000Z

351

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

352

Study of gain and photoresponse characteristics for back-illuminated separate absorption and multiplication GaN avalanche photodiodes  

SciTech Connect (OSTI)

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

353

Multicycle rapid thermal annealing optimization of Mg-implanted GaN: Evolution of surface, optical, and structural properties  

SciTech Connect (OSTI)

The first step of a multi-cycle rapid thermal annealing process was systematically studied. The surface, structure, and optical properties of Mg implanted GaN thin films annealed at temperatures ranging from 900 to 1200?C were investigated by Raman spectroscopy, photoluminescence, UV-visible spectroscopy, atomic force microscopy, and Nomarski microscopy. The GaN thin films are capped with two layers of in-situ metal organic chemical vapor deposition -grown AlN and annealed in 24 bar of N{sub 2} overpressure to avoid GaN decomposition. The crystal quality of the GaN improves with increasing annealing temperature as confirmed by UV-visible spectroscopy and the full widths at half maximums of the E{sub 2} and A{sub 1} (LO) Raman modes. The crystal quality of films annealed above 1100?C exceeds the quality of the as-grown films. At 1200?C, Mg is optically activated, which is determined by photoluminescence measurements. However, at 1200?C, the GaN begins to decompose as evidenced by pit formation on the surface of the samples. Therefore, it was determined that the optimal temperature for the first step in a multi-cycle rapid thermal anneal process should be conducted at 1150?C due to crystal quality and surface morphology considerations.

Greenlee, Jordan D., E-mail: jordan.greenlee.ctr@nrl.navy.mil [National Research Council, 500 Fifth St. NW, Washington, DC 20001 (United States); Feigelson, Boris N.; Anderson, Travis J.; Hite, Jennifer K.; Mastro, Michael A.; Eddy, Charles R.; Hobart, Karl D.; Kub, Francis J. [Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (United States); Tadjer, Marko J. [American Society for Engineering Education, 1818 N St. NW, Washington, DC 20036 (United States)

2014-08-14T23:59:59.000Z

354

Multiband GaNAsP Quaternary Alloys  

SciTech Connect (OSTI)

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

355

A New Combustion Synthesis Method for GaN:Eu3+ and Ga2O3 :Eu3+  

E-Print Network [OSTI]

A New Combustion Synthesis Method for GaN:Eu3+ and Ga2O3 :Eu3+ Luminescent Powders G. A. Hirata1 between the precursors. The preparation of Eu-doped Ga2O3 powders was achieved using a new combustion)3 and Ga(NO3)3 as the precursors and hydrazine as (non-carbonaceous) fuel. A spontaneous combustion

McKittrick, Joanna

356

SURFACE RADAR REPORTING 7.1. General. Radar observations of tropical cyclones will be made at Department of Defense  

E-Print Network [OSTI]

. Worth, TX Greer, SC Houston, TX Huntsville/Hytop, AL Jacksonville, FL Key West, FL Lake Charles, LA Melbourne, FL Miami, FL Mobile, AL Morehead City, NC New Orleans/Baton Rouge, LA New York City, NY

357

Recent progress in InGaAsSb/GaSb TPV devices  

SciTech Connect (OSTI)

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

Chemical structure of vanadium-based contact formation on n-AlN  

SciTech Connect (OSTI)

We have investigated the chemical interaction between a Au/V/Al/V layer structure and n-type AlN epilayers using soft x-ray photoemission, x-ray emission spectroscopy, and atomic force microscopy. To understand the complex processes involved in this multicomponent system, we have studied the interface before and after a rapid thermal annealing step. We find the formation of a number of chemical phases at the interface, including VN, metallic vanadium, aluminum oxide, and metallic gold. An interaction mechanism for metal contact formation on the entire n-(Al,Ga)N system is proposed.

Pookpanratana, S.; France, R.; Blum, M.; Bell, A.; Bar, M.; Weinhardt, L.; Zhang, Y.; Hofmann, T.; Fuchs, O.; Yang, W.; Denlinger, J. D.; Mulcahy, S.; Moustakas, T. D.; Heske, Clemens

2010-05-17T23:59:59.000Z

359

Lattice-Mismatched GaAs/InGaAs Two-Junction Solar Cells by Direct Wafer Bonding  

SciTech Connect (OSTI)

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

360

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

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

ALS Evidence Confirms Combustion Theory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Evidence Confirms Combustion Theory ALS Evidence Confirms Combustion Theory Print Wednesday, 22 October 2014 11:43 Researchers recently uncovered the first step in the process...

362

Point defect balance in epitaxial GaSb  

SciTech Connect (OSTI)

Positron annihilation spectroscopy in both conventional and coincidence Doppler broadening mode is used for studying the effect of growth conditions on the point defect balance in GaSb:Bi epitaxial layers grown by molecular beam epitaxy. Positron annihilation characteristics in GaSb are also calculated using density functional theory and compared to experimental results. We conclude that while the main positron trapping defect in bulk samples is the Ga antisite, the Ga vacancy is the most prominent trap in the samples grown by molecular beam epitaxy. The results suggest that the ptype conductivity is caused by different defects in GaSb grown with different methods.

Segercrantz, N., E-mail: natalie.segercrantz@aalto.fi; Slotte, J.; Makkonen, I.; Kujala, J.; Tuomisto, F. [Department of Applied Physics, Aalto University, P.O. Box 14100, FIN-00076 Aalto Espoo (Finland); Song, Y.; Wang, S. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Gteborg (Sweden); State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences 865 Changning Road, Shanghai 200050 (China)

2014-08-25T23:59:59.000Z

363

Optically pumped cerium-doped LiSrAlF{sub 6} and LiCaAlF{sub 6}  

DOE Patents [OSTI]

Ce{sup 3+}-doped LiSrAlF{sub 6} crystals are pumped by ultraviolet light which is polarized along the c axis of the crystals to effectively energize the laser system. In one embodiment, the polarized fourth harmonic light output from a conventional Nd:YAG laser operating at 266 nm is arranged to pump Ce:LiSrAlF{sub 6} with the pump light polarized along the c axis of the crystal. The Ce:LiSrAlF{sub 6} crystal may be placed in a laser cavity for generating tunable coherent ultraviolet radiation in the range of 280-320 nm. Additionally, Ce-doped crystals possessing the LiSrAlF{sub 6} type of chemical formula, e.g. Ce-doped LiCaAlF{sub 6} and LiSrGaF{sub 6}, can be used. Alternative pump sources include an ultraviolet-capable krypton or argon laser, or ultraviolet emitting flashlamps. The polarization of the pump light will impact operation. The laser system will operate efficiently when light in the 280-320 nm gain region is injected or recirculated in the system such that the beam is also polarized along the c axis of the crystal. The Ce:LiSrAlF{sub 6} laser system can be configured to generate ultrashort pulses, and it may be used to pump other devices, such as an optical parametric oscillator. 10 figs.

Marshall, C.D.; Payne, S.A.; Krupke, W.F.

1996-05-14T23:59:59.000Z

364

Optically pumped cerium-doped LiSrAlF.sub.6 and LiCaAlF.sub.6  

DOE Patents [OSTI]

Ce.sup.3+ -doped LiSrAlF.sub.6 crystals are pumped by ultraviolet light which is polarized along the c axis of the crystals to effectively energize the laser system. In one embodiment, the polarized fourth harmonic light output from a conventional Nd:YAG laser operating at 266 nm is arranged to pump Ce:LiSrAlF.sub.6 with the pump light polarized along the c axis of the crystal. The Ce:LiSrAlF.sub.6 crystal may be placed in a laser cavity for generating tunable coherent ultraviolet radiation in the range of 280-320 nm. Additionally, Ce-doped crystals possessing the LiSrAlF.sub.6 type of chemical formula, e.g. Ce-doped LiCaAlF.sub.6 and LiSrGaF.sub.6, can be used. Alternative pump sources include an ultraviolet-capable krypton or argon laser, or ultraviolet emitting flashlamps. The polarization of the pump light will impact operation. The laser system will operate efficiently when light in the 280-320 nm gain region is injected or recirculated in the system such that the beam is also polarized along the c axis of the crystal. The Ce:LiSrAlF.sub.6 laser system can be configured to generate ultrashort pulses, and it may be used to pump other devices, such as an optical parametric oscillator.

Marshall, Christopher D. (Livermore, CA); Payne, Stephen A. (Castro Valley, CA); Krupke, William F. (Pleasanton, CA)

1996-01-01T23:59:59.000Z

365

ALS in the News  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home|PhysicsGasandArgonneALS in the News ALS in the

366

ALS in the News  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home|PhysicsGasandArgonneALS in the News ALS in

367

InGaAs/InP DHBTs WITH A 75nm COLLECTOR, 20nm BASE DEMONSTRATING 544 GHz f , BVCEO = 3.2V, and BVCBO = 3.4V  

E-Print Network [OSTI]

InGaAs/InP DHBTs WITH A 75nm COLLECTOR, 20nm BASE DEMONSTRATING 544 GHz f , BVCEO = 3.2V, and BVCBOGaAs base and a 75 nm InP collector containing an InGaAs/InAlAs superlattice grade. These devices exhibit collector thickness for any HBT. The devices have been scaled vertically for reduced base and collector

Rodwell, Mark J. W.

368

Nano-scale characterization of GaAsP/GaAs strained superlattice structure by nano-beam electron diffraction  

SciTech Connect (OSTI)

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

369

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

370

Optical ridge waveguides in AlGaAs and LiNbO3  

E-Print Network [OSTI]

photodiode. Power Supply polarizer Ti: Sapphire pl e waveguide Power 40x lens Photodiode argon pump laser Fig. 20 Test setup for photocurrent measurement. 35 Contact to the electrodes was made by probes that are mechanically lowered using a... to their power loss and their mode proSe. The power loss for these waveguides was measured using the system shown in Fig. 23. 0. 63 ltm laser 42 plate waveguide Photodiode 40x 20x lens lens Power Meter Fig. 23 Test setup for power loss measurement...

Terry, Roger Mark

2012-06-07T23:59:59.000Z

371

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

372

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.

373

0.7-eV GaInAs Junction for a GaInP/GaAs/GaInAs(1eV)/GaInAs(0.7eV) Four-Junction Solar Cell  

SciTech Connect (OSTI)

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

374

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.

375

Photocapacitance study of type-II GaSb/GaAs quantum ring solar cells  

SciTech Connect (OSTI)

In this study, the density of states associated with the localization of holes in GaSb/GaAs quantum rings are determined by the energy selective charging of the quantum ring distribution. The authors show, using conventional photocapacitance measurements, that the excess charge accumulated within the type-II nanostructures increases with increasing excitation energies for photon energies above 0.9?eV. Optical excitation between the localized hole states and the conduction band is therefore not limited to the ?(k?=?0) point, with pseudo-monochromatic light charging all states lying within the photon energy selected. The energy distribution of the quantum ring states could consequently be accurately related from the excitation dependence of the integrated photocapacitance. The resulting band of localized hole states is shown to be well described by a narrow distribution centered 407?meV above the GaAs valence band maximum.

Wagener, M. C.; Botha, J. R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Carrington, P. J.; Krier, A. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

2014-01-07T23:59:59.000Z

376

Efficiency enhancement of InGaN/GaN solar cells with nanostructures  

SciTech Connect (OSTI)

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

377

Graphene in ohmic contact for both n-GaN and p-GaN  

SciTech Connect (OSTI)

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 IV 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

Wavelength limits for InGaN quantum wells on GaN  

SciTech Connect (OSTI)

The emission wavelength of coherently strained InGaN quantum wells (QW) is limited by the maximum thickness before relaxation starts. For high indium contents x>40% the resulting wavelength decreases because quantum confinement dominates. For low indium content x<40% the electron hole wave function overlap (and hence radiative emission) is strongly reduced with increasing QW thickness due to the quantum confined Stark effect and imposes another limit. This results in a maximum usable emission wavelength at around 600?nm for QWs with 40%-50% indium content. Relaxed InGaN buffer layers could help to push this further, especially on non- and semi-polar orientations.

Pristovsek, Markus, E-mail: markus@pristovsek.de [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)] [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

2013-06-17T23:59:59.000Z

379

Application of the ASME code in the design of the GA-4 and GA-9 casks  

SciTech Connect (OSTI)

General Atomics (GA) is developing two spent fuel shipping casks for transport by legal weight truck (LWT). The casks are designed to the loading, environmental conditions and safety requirements defined in Title 10 of the Code of Federal Regulations, Part 71 (10CFR71). To ensure that all components of the cask meet the 10CFR71 rules, GA established structural design criteria for each component based on NRC Regulatory Guides and the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code). This paper discusses the criteria used for different cask components, how they were applied and the conservatism and safety margins built into the criteria and assumption.

Mings, W.J. (USDOE Idaho Field Office, Idaho Falls, ID (United States)); Koploy, M.A. (General Atomics, San Diego, CA (United States))

1992-01-01T23:59:59.000Z

380

Application of the ASME code in the design of the GA-4 and GA-9 casks  

SciTech Connect (OSTI)

General Atomics (GA) is developing two spent fuel shipping casks for transport by legal weight truck (LWT). The casks are designed to the loading, environmental conditions and safety requirements defined in Title 10 of the Code of Federal Regulations, Part 71 (10CFR71). To ensure that all components of the cask meet the 10CFR71 rules, GA established structural design criteria for each component based on NRC Regulatory Guides and the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code). This paper discusses the criteria used for different cask components, how they were applied and the conservatism and safety margins built into the criteria and assumption.

Mings, W.J. [USDOE Idaho Field Office, Idaho Falls, ID (United States); Koploy, M.A. [General Atomics, San Diego, CA (United States)

1992-08-01T23:59:59.000Z

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

Origins of ion irradiation-induced Ga nanoparticle motion on GaAs surfaces  

SciTech Connect (OSTI)

We have examined the origins of ion irradiation-induced nanoparticle (NP) motion. Focused-ion-beam irradiation of GaAs surfaces induces random walks of Ga NPs, which are biased in the direction opposite to that of ion beam scanning. Although the instantaneous NP velocities are constant, the NP drift velocities are dependent on the off-normal irradiation angle, likely due to a difference in surface non-stoichiometry induced by the irradiation angle dependence of the sputtering yield. It is hypothesized that the random walks are initiated by ion irradiation-induced thermal fluctuations, with biasing driven by anisotropic mass transport.

Kang, M.; Wu, J. H.; Chen, H. Y.; Thornton, K.; Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Sofferman, D. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Adelphi University, Garden City, New York 11530-0701 (United States); Beskin, I. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

2013-08-12T23:59:59.000Z

382

Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots  

SciTech Connect (OSTI)

In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

Braun, T.; Schneider, C.; Maier, S.; Forchel, A.; Hfling, S.; Kamp, M. [Technische Physik, Physikalisches Institut and Wilhelm Conrad Rntgen-Research Center for Complex Material Systems, Universitt Wrzburg, Am Hubland, D-97074, Wrzburg (Germany); Igusa, R.; Iwamoto, S.; Arakawa, Y. [University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505 (Japan)

2014-09-15T23:59:59.000Z

383

Measurement of the Inclusive e{\\pm}p Scattering Cross Section at High Inelasticity y and of the Structure Function FL  

E-Print Network [OSTI]

A measurement is presented of the inclusive neutral current e\\pm p scattering cross section using data collected by the H1 experiment at HERA during the years 2003 to 2007 with proton beam energies Ep of 920, 575, and 460 GeV. The kinematic range of the measurement covers low absolute four-momentum transfers squared, 1.5 GeV2 < Q2 < 120 GeV2, small values of Bjorken x, 2.9 \\cdot 10-5 < x < 0.01, and extends to high inelasticity up to y = 0.85. The structure function FL is measured by combining the new results with previously published H1 data at Ep = 920 GeV and Ep = 820 GeV. The new measurements are used to test several phenomenological and QCD models applicable in this low Q2 and low x kinematic domain.

Aaron, F D; Andreev, V; Backovic, S; Baghdasaryan, A; Baghdasaryan, S; Barrelet, E; Bartel, W; Behrend, O; Belov, P; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Britzger, D; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bylinkin, A; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Ceccopieri, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cvach, J; Dainton, J B; Daum, K; Delcourt, B; Delvax, J; De Wolf, E A; Diaconu, C; Dobre, M; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Egli, S; Eliseev, A; Elsen, E; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Grebenyuk, A; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C.W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Huber, F; Jacquet, M; Janssen, X; Jonsson, L; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Kretzschmar, J; Kruger, K; Kutak, K; Landon, M P.J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Lendermann, V; Levonian, S; Lipka, K; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Makankine, A; Malinovski, E; Marage, P; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Mudrinic, M; Muller, K; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nikitin, D; Nowak, G; Nowak, K; Olsson, J E; Osman, S; Ozerov, D; Pahl, P; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pirumov, H; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Radescu, V; Raicevic, N; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rusakov, S; Salek, D; Sankey, D P.C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, I; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, A; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sykora, T; Thompson, P D; Toll, T; Tran, T H; Traynor, D; Truol, P; Tsakov, I; Tseepeldorj, B; Tsurin, I; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas, A; Vazdik, Y; von den Driesch, M; Wegener, D; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zohrabyan, H; Zomer, F

2011-01-01T23:59:59.000Z

384

Panel: Microgrid Research and Field Testing IEEE PES General Meeting, 24-28 June 2007, Tampa, FL 1 In general, a microgrid can operate in both the grid-connected  

E-Print Network [OSTI]

Panel: Microgrid Research and Field Testing IEEE PES General Meeting, 24-28 June 2007, Tampa, FL 1 Abstract In general, a microgrid can operate in both the grid-connected mode and the islanded mode where the microgrid is interfaced to the main power system by a fast semiconductor switch called static switch, (SS

385

211 Westcott Building, 222 S. Copeland Avenue, P.O. Box 3061480, Tallahassee, FL 32306-1480 Telephone 850.644.6876, Fax 850.644.3375 http://fda.fsu.edu  

E-Print Network [OSTI]

211 Westcott Building, 222 S. Copeland Avenue, P.O. Box 3061480, Tallahassee, FL 32306 Development and Advancement in Westcott 115 by Friday, March 21, 2014, for submission to the President and Advancement in Westcott 115 for each specialized faculty. Article 14 (and Appendix J of the FSU-BOT UFF

Sura, Philip

386

JOURNAL DE PHYSIQUE Colloque C6, supplkment au no 12, Tome 37, DPcembre 1976,page C6-897 M~SSBAUERSTUDIES OF' lZ9IATOMS IMPLANTED IN a-AND fl-TIN  

E-Print Network [OSTI]

~SSBAUERSTUDIES OF' lZ9IATOMS IMPLANTED IN a- AND fl-TIN H. DE WAARD and G. J. KEMERINK Laboratorium voor Algemene on the basis of a simple model. Implants of 1291 in /3 tin yield two line spectra identicalto those found for implants in a tin converted to /3 tin by heating. Repeated phase transitions show that the impurity

Paris-Sud XI, Universit de

387

Greitzer, F.L. April 2000. "Life Extension Analysis and Prognostics Architectures," Laboratory Directed Research and Development Annual Report, Fiscal Year 1999, pp. 85-88. PNNL-13203. U.S. Department of Energy. Richland, Washington.  

E-Print Network [OSTI]

of Energy. Richland, Washington. Life-Extension Analysis and Prognostics Architectures Frank L. GreitzerGreitzer, F.L. April 2000. "Life Extension Analysis and Prognostics Architectures," Laboratory that perform sensor fusion, analysis, reporting and interpreting of results with little or no human

388

ALS Communications Group  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation InInformation InExplosion Monitoring:Home|PhysicsGasandArgonne LeadershipBeamlines ALS

389

About the ALS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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390

2015 ALS Shutdown  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011 Mon, Next ReleaseEFRC5 Calendar2015 ALS Shutdown

391

ALS Activity Reports  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011Astudies smart sensors andScience atScienceALS

392

ALS Beamlines Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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393

ALS Beamlines Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011Astudies smart sensors andScienceALS

394

ALS Communications Group  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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395

ALS in the News  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary)morphinanInformation Desert SouthwestTechnologies |November 2011Astudies smartHistory: The FirstUsers'ALS

396

ALS Beamlines Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience4AJ01) (See95TI07)Operations During the months3ALCCActivity ReportsALS

397

ALS Beamlines Directory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience4AJ01) (See95TI07)Operations During the months3ALCCActivityALS

398

ALS Chemistry Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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399

ALS Chemistry Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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400

Phonon-drag thermopower in anisotropic AlAs quantum wells  

SciTech Connect (OSTI)

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 Universitt 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

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

O?[]O? nuclear ?-decay of ?Ga  

E-Print Network [OSTI]

information, MARS was focused such that only fully stripped N=Z ions were passed, with the vast majority of them being Ga. The second phase of the experiment was a I3-y coincidence experiment. At the back-end of MARS, a 1" x 1 '!4" x 3" four..., using the Weinberg-Salam model of electroweak interactions, to be [23]: A& ? d, ?= ? [41n(mz/m )+ln(m /m?)+2K+A +" ]. (16) Here mz is the mass of the Z boson, me the proton mass, mx is the low energy cutoff for the second and third terms that arise...

Hyman, Bruce Carl

1999-01-01T23:59:59.000Z

402

General Atomics (GA) | Princeton Plasma Physics Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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403

GA SNC Solar | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartmentAUDIT REPORTOpen EnergyBoard" form. To create aGA SNC Solar Jump to:

404

Theoretical studies of optical gain tuning by hydrostatic pressure in GaInNAs/GaAs quantum wells  

SciTech Connect (OSTI)

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

405

Mesoscopic photovoltaic effect in GaAs/Ga1-xAlxAs Aharonov-Bohm rings L. Angers, A. Chepelianskii, R. Deblock, B. Reulet, and H. Bouchiat  

E-Print Network [OSTI]

Mesoscopic photovoltaic effect in GaAs/Ga1-xAlxAs Aharonov-Bohm rings L. Angers, A. Chepelianskii specific dc voltage. We have investigated this photovoltaic PV effect on GaAs/Ga1-xAlxAs Aharonov is generally done by measuring the dc induced signal sometimes called photovoltaic effect which has also given

Shepelyansky, Dima

406

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

Broader source: Energy.gov (indexed) [DOE]

current due to bulk defects GaN is Grown Heteroepitaxially on Sapphire (and Silicon Carbide) Substrates * As grown GaN nucleation layers contain disordered GaN with many...

407

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.

408

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

409

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

410

Partially filled intermediate band of Cr-doped GaN films  

SciTech Connect (OSTI)

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

411

Elastic properties of Pu metal and Pu-Ga alloys  

SciTech Connect (OSTI)

We present elastic properties, theoretical and experimental, of Pu metal and Pu-Ga ({delta}) alloys together with ab initio equilibrium equation-of-state for these systems. For the theoretical treatment we employ density-functional theory in conjunction with spin-orbit coupling and orbital polarization for the metal and coherent-potential approximation for the alloys. Pu and Pu-Ga alloys are also investigated experimentally using resonant ultrasound spectroscopy. We show that orbital correlations become more important proceeding from {alpha} {yields} {beta} {yields} {gamma} plutonium, thus suggesting increasing f-electron correlation (localization). For the {delta}-Pu-Ga alloys we find a softening with larger Ga content, i.e., atomic volume, bulk modulus, and elastic constants, suggest a weakened chemical bonding with addition of Ga. Our measurements confirm qualitatively the theory but uncertainties remain when comparing the model with experiments.

Soderlind, P; Landa, A; Klepeis, J E; Suzuki, Y; Migliori, A

2010-01-05T23:59:59.000Z

412

OPTIMIZATION OF GaN WINDOW LAYER FOR InGaN SOLAR CELLS USING POLARIZATION EFFECT  

E-Print Network [OSTI]

on the design of wide-band gap GaN window layers for InGaN solar cells. Window layers serve to passivate the top into account during design of the solar cell to improve its collection efficiency. Previously, we have. The present work is a subset of the design optimization process for such solar cells, where we focus

Honsberg, Christiana

413

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

414

Diffusion of a Ga adatom on the GaAs(001)c(44)heterodimer surface: A first principles study  

E-Print Network [OSTI]

Diffusion of a Ga adatom on the GaAs(001)c(44)heterodimer surface: A first principles study J Diffusion barriers Reconstruction Density functional calculations The adsorption and diffusion behavior functional theory (DFT) computations in the local density approxima- tion. Structural and bonding features

Khare, Sanjay V.

415

Electric field dependent radiative decay kinetics of polar InGaN/GaN quantum heterostructures at low fields  

E-Print Network [OSTI]

Electric field dependent radiative decay kinetics of polar InGaN/GaN quantum heterostructures with increasing external electric field, with the radiative component exhibiting weaker field dependence. 2009 applied electric field in Ref. 12, the electric field dependent radiative recombination in particular has

Demir, Hilmi Volkan

416

Optical study of hydrogen-irradiated GaAsN/GaAs heterostructures M. Geddo,1,a)  

E-Print Network [OSTI]

Optical study of hydrogen-irradiated GaAsN/GaAs heterostructures M. Geddo,1,a) M. Patrini,1 G; accepted 5 May 2011; published online 20 June 2011) The effect of hydrogen irradiation on the optical for fiber optic communications. These promising results in view of the development of waveguides deserve

417

Wavelength-resolved low-frequency noise of GaInN/GaN green light emitting diodes  

E-Print Network [OSTI]

Wavelength-resolved low-frequency noise of GaInN/GaN green light emitting diodes S. L. Rumyantseva well light emitting diodes. The light intensity noise was measured as a function of wavelength within the light emitting diode spectral emission line. The spectral noise density is found to increase

Wetzel, Christian M.

418

Evaluation of the two-photon absorption characteristics of GaSb/GaAs quantum rings  

SciTech Connect (OSTI)

The optical parameters describing the sub-bandgap response of GaSb/GaAs quantum rings solar cells have been obtained from photocurrent measurements using a modulated pseudo-monochromatic light source in combination with a second, continuous photo-filling source. By controlling the charge state of the quantum rings, the photoemission cross-sections describing the two-photon sub-bandgap transitions could be determined independently. Temperature dependent photo-response measurements also revealed that the barrier for thermal hole emission from the quantum rings is significantly below the quantum ring localisation energy. The temperature dependence of the sub-bandgap photo-response of the solar cell is also described in terms of the photo- and thermal-emission characteristics of the quantum rings.

Wagener, M. C.; Botha, J. R. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Carrington, P. J. [Department of Electronic and Electrical Engineering, University College London, London (United Kingdom); Krier, A. [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

2014-07-28T23:59:59.000Z

419

Single photon emission from site-controlled InGaN/GaN quantum dots  

SciTech Connect (OSTI)

Single photon emission was observed from site-controlled InGaN/GaN quantum dots. The single-photon nature of the emission was verified by the second-order correlation function up to 90?K, the highest temperature to date for site-controlled quantum dots. Micro-photoluminescence study on individual quantum dots showed linearly polarized single exciton emission with a lifetime of a few nanoseconds. The dimensions of these quantum dots were well controlled to the precision of state-of-the-art fabrication technologies, as reflected in the uniformity of their optical properties. The yield of optically active quantum dots was greater than 90%, among which 13%25% exhibited single photon emission at 10?K.

Zhang, Lei; Hill, Tyler A.; Deng, Hui, E-mail: dengh@umich.edu [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109 (United States)] [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109 (United States); Teng, Chu-Hsiang; Lee, Leung-Kway; Ku, Pei-Cheng, E-mail: peicheng@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)] [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

2013-11-04T23:59:59.000Z

420

Sidewall passivation for InGaN/GaN nanopillar light emitting diodes  

SciTech Connect (OSTI)

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

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

Strain relaxation effect by nanotexturing InGaN/GaN multiple quantum well  

SciTech Connect (OSTI)

The relaxation of lattice-mismatched strain by deep postetching was systematically investigated for InGaN/GaN multiple quantum wells (MQWs). A planar heterojunction wafer, which included an In{sub 0.21}Ga{sub 0.79}N (3.2 nm)/GaN (14.8 nm) MQW, was etched by inductively coupled plasma dry etching, to fabricate high-density nanopillar, nanostripe, and nanohole arrays. The etching depth was 570 nm for all nanostructures. The diameter of the nanopillars was varied from 50 to 300 nm, then the mesa stripe width of the nanostripes and the diameter of the nanoholes were varied from 100 nm to 440 nm and 50 nm to 310 nm, respectively. The effect of strain relaxation on various optical properties was investigated. For example, in an array of nanopillars with diameter 130 nm and interval 250 nm, a large blueshift in the photoluminescence (PL) emission peak from 510 nm (as-grown) to 459 nm occurred at room temperature (RT). PL internal quantum efficiency (defined by the ratio of PL integral intensity at 300 K to that at 4.2 K) was enhanced from 34% (as-grown) to 60%, and the PL decay time at 4.2 K was reduced from 22 ns (as-grown) to 4.2 ns. These results clearly indicate the reduction of lattice-mismatched strain by postetching, which enhanced strain reduction with decreasing nanopillar diameter down to a diameter of 130 nm, where the strain reduction became saturated. The dependence of RT-PL decay time on nanopillar diameter was measured, and the surface nonradiative recombination velocity was estimated to be 5.8x10{sup 2} cm/s. This relatively slow rate indicates a little etching damage.

Ramesh, V.; Kikuchi, A.; Kishino, K. [Department of Electrical and Electronics Engineering, Sophia University, Tokyo 102-8554, Japan and Nano-technology Research Center, Sophia University, Tokyo 102-8554 (Japan); CREST, JST, Saitama 332-0012 (Japan); Funato, M.; Kawakami, Y. [CREST, JST, Saitama 332-0012 (Japan); Department of Electronics Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan)

2010-06-15T23:59:59.000Z

422

Entertainment Technology Center, CMU Internship Survey Results, Dec 2013, May 2014, and Dec 2014  

E-Print Network [OSTI]

Developer Mount Pleasant SC Visionary Works LLC UX Designer, Game Programmer Washington DC VOCI Technology, NM, OK, TX 2 West: CA, HI, NV 16 Southeast: AL, AR, FL, GA, KY, LA, MS, NC, PR, SC, TN 1 Midwest: IA Emails 28 Faculty Contacts 22 Personal Network 17 Interviews Arranged by Career Services 9 Intern Search

Matsuda, Noboru

423

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

424

CountriesofOriginMap-Sign.indd  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

scientists are called users. They come from around the world to use our magnets. WY WA CA UT UT CO NM TX TX OK FL GA TN SC NC VI MI IL NY MA MA PA AL N H V T IN OH MO IA MN WI...

425

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (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...

426

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (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...

427

Annual Energy Outlook 2012  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (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...

428

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (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...

429

U.S. Energy Information Administration | Annual Energy Outlook...  

Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

Coal supply regions 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...

430

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...

431

Annual Energy Outlook 2012  

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...

432

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...

433

Presented at the International Joint Conference on Information Systems, Fuzzy Theory and Technology Conference, Atlantic City, N.J. March 2, 2000.  

E-Print Network [OSTI]

published regarding the combination of fuzzy logic (FL) and genetic algorithms (GA) (Herrera and Verdegay 1999). Fuzzy logic is a useful tool for modeling complex systems and deriving useful fuzzy relations systems (Chen 1998) or fuzzy control systems (Tang et. al. 1998); our goal is to maximize the similarity

Bridges, Susan M.

434

ALS Evidence Confirms Combustion Theory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Evidence Confirms Combustion Theory Print Researchers recently uncovered the first step in the process that transforms gas-phase molecules into solid particles like soot and...

435

Field dependent emission rates in radiation damaged GaAs  

SciTech Connect (OSTI)

We have measured the temperature and field dependence of emission rates from five traps in electron damaged GaAs. Four of the traps have previously been identified as radiation defects. One of the traps, seen in higher doped diodes, has not been previously identified. We have fit the data to a multiphonon emission theory that allows recombination in GaAs to be characterized over a broad range of temperature and electric field. These results demonstrate an efficient method to calculate field-dependent emission rates in GaAs.

Fleming, R. M.; Myers, S. M.; Wampler, W. R.; Lang, D. V.; Seager, C. H.; Campbell, J. M. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1415 (United States)

2014-07-07T23:59:59.000Z

436

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

437

GA Hot Cell D&D Closeout Report  

Office of Legacy Management (LM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarlyEnergyDepartment ofDepartment ofof EnergyYou$0.C. 20545*. . : '* FEB1f\l p :.;LIST OFK I

438

Effect of Sb on the Properties of GaInP Top Cells (Presentation)  

SciTech Connect (OSTI)

The summary of this report is that: (1) Sb can be used to increase V{sub oc} of a GaInP top cell; (2) the photovoltaic quality of GaInP is relatively unaffected by the presence of Sb; and (3) Sb-doped GaInP/GaAs tandem cells show promise for achieving efficiencies over 32%.

Olson, J. M.; McMahon, W. E.; Kurtz, S.

2006-05-01T23:59:59.000Z

439

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.

440

Microscopic, electrical and optical studies on InGaN/GaN quantum wells based LED devices  

SciTech Connect (OSTI)

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 "al fl 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

Waveguide effect of GaAsSb quantum wells in a laser structure based on GaAs  

SciTech Connect (OSTI)

The waveguide effect of GaAsSb quantum wells in a semiconductor-laser structure based on GaAs is studied theoretically and experimentally. It is shown that quantum wells themselves can be used as waveguide layers in the laser structure. As the excitation-power density attains a value of 2 kW/cm{sup 2} at liquid-nitrogen temperature, superluminescence at the wavelength corresponding to the optical transition in bulk GaAs (at 835 nm) is observed.

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); Afonenko, A. A. [Belarussian State University (Belarus)] [Belarussian State University (Belarus); Dikareva, N. V. [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)] [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation); Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru; Kudryavtsev, K. E.; Morozov, S. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Nekorkin, S. M. [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)] [Research Physical-Technical Institute of Nizhni Novgorod State University (Russian Federation)

2013-11-15T23:59:59.000Z

442

Electrical spin injection using GaCrN in a GaN based spin light emitting diode  

SciTech Connect (OSTI)

We have demonstrated electrical spin-injection from GaCrN dilute magnetic semiconductor (DMS) in a GaN-based spin light emitting diode (spin-LED). The remanent in-plane magnetization of the thin-film semiconducting ferromagnet has been used for introducing the spin polarized electrons into the non-magnetic InGaN quantum well. The output circular polarization obtained from the spin-LED closely follows the normalized in-plane magnetization curve of the DMS. A saturation circular polarization of ?2.5% is obtained at 200?K.

Banerjee, D.; Ganguly, S.; Saha, D., E-mail: dipankarsaha@iitb.ac.in [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); IITB-Monash Research Academy, Indian Institute of Technology Bombay, Mumbai 400076 (India); Adari, R.; Sankaranarayan, S.; Kumar, A. [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India)] [Centre of Excellence in Nanoelectronics, Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai 400076 (India); Aldhaheri, R. W.; Hussain, M. A.; Balamesh, A. S. [Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)] [Department of Electrical and Computer Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

2013-12-09T23:59:59.000Z

443

Temperature dependence of photoconductivity in Zn-doped GaN  

SciTech Connect (OSTI)

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

444

Beta-decay branching ratios of 62Ga  

E-Print Network [OSTI]

Beta-decay branching ratios of 62Ga have been measured at the IGISOL facility of the Accelerator Laboratory of the University of Jyvaskyla. 62Ga is one of the heavier Tz = 0, 0+ -> 0+ beta-emitting nuclides used to determine the vector coupling constant of the weak interaction and the Vud quark-mixing matrix element. For part of the experimental studies presented here, the JYFLTRAP facility has been employed to prepare isotopically pure beams of 62Ga. The branching ratio obtained, BR= 99.893(24)%, for the super-allowed branch is in agreement with previous measurements and allows to determine the ft value and the universal Ft value for the super-allowed beta decay of 62Ga.

A. Bey; B. Blank; G. Canchel; C. Dossat; J. Giovinazzo; I. Matea; V. Elomaa; T. Eronen; U. Hager; M. Hakala; A. Jokinen; A. Kankainen; I. Moore; H. Penttila; S. Rinta-Antila; A. Saastamoinen; T. Sonoda; J. Aysto; N. Adimi; G. De France; J. C. Thomas; G. Voltolini; T. Chaventr

2008-04-17T23:59:59.000Z

445

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

446

Lattice vibrations of pure and doped GaSe  

SciTech Connect (OSTI)

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

447

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

448

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

SciTech Connect (OSTI)

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

449

Allegato "B" DOMANDA DI PARTECIPAZIONE AL CONCORSO DI AMMISSIONE AL  

E-Print Network [OSTI]

IN ROBOTICA, NEUROSCIENZE, NANOTECNOLOGIE E SCOPERTA FARMACI IN COLLABORAZIONE CON LA FONDAZIONE IIT Si prega'ammissione al Corso di Dottorato di Ricerca in Robotica, Neuroscienze, Nanotecnologie e Scoperta Farmaci

Sandini, Giulio

450

Al Akhawayn University Al Akhawayn partner of TUM since 2002  

E-Print Network [OSTI]

Haddouti Dissertation at Chair for Databases (Prof. Bayer), Professor at Al Akhawayn, now working at BMW (TUM & AUI Alumni) BMW, Hachim.haddouti@bmw.de #12;Double Degree TUM - Georgia Tech Fakultt fr

Cengarle, Mara Victoria

451

Al Akhawayn University Al Akhawayn partner of TUM since 2002  

E-Print Network [OSTI]

Haddouti Dissertation at Chair for Databases (Prof. Bayer), Professor at Al Akhawayn, now working at BMW) BMW, Hachim.haddouti@bmw.de #12;Double Degree TUM - Georgia Tech Fakultt fr Informatik TUM School

Cengarle, Mara Victoria

452

Al Akhawayn University Al Akhawayn partner of TUM since 2002  

E-Print Network [OSTI]

Haddouti Dissertation at Chair for Databases (Prof. Bayer), Professor at Al Akhawayn, now working at BMW Alumni) BMW, Hachim.haddouti@bmw.de #12;Double Degree TUM - Georgia Tech Fakultt fr Informatik TUM

Cengarle, Mara Victoria

453

Anti-phase domains in cubic GaN  

SciTech Connect (OSTI)

The existence of anti-phase domains in cubic GaN grown on 3C-SiC/Si (001) substrates by plasma-assisted molecular beam epitaxy is reported. The influence of the 3C-SiC/Si (001) substrate morphology is studied with emphasis on the anti-phase domains (APDs). The GaN nucleation is governed by the APDs of the substrate, resulting in equal plane orientation and the same anti-phase boundaries. The presence of the APDs is independent of the GaN layer thickness. Atomic force microscopy surface analysis indicates lateral growth anisotropy of GaN facets in dependence of the APD orientation. This anisotropy can be linked to Ga and N face types of the {l_brace}111{r_brace} planes, similar to observations of anisotropic growth in 3C-SiC. In contrast to 3C-SiC, however, a difference in GaN phase composition for the two types of APDs can be measured by electron backscatter diffraction, {mu}-Raman and cathodoluminescence spectroscopy.

Maria Kemper, Ricarda; Schupp, Thorsten; Haeberlen, Maik; Lindner, Joerg; Josef As, Donat [University of Paderborn, Department of Physics, Warburger Str. 100, D-33098 Paderborn (Germany); Niendorf, Thomas; Maier, Hans-Juergen [University of Paderborn, Lehrstuhl fuer Werkstoffkunde, Pohlweg 47-49, D-33098 Paderborn (Germany); Dempewolf, Anja; Bertram, Frank; Christen, Juergen [University of Magdeburg, Institut fuer Festkoerperphysik, P.O. Box 4120, D-39016 Magdeburg (Germany); Kirste, Ronny; Hoffmann, Axel [Technische Universitaet Berlin, Institute of Solid State Physics, Hardenbergstr. 36, D-10623 Berlin (Germany)

2011-12-15T23:59:59.000Z

454

Suppression of electron magnetotunneling between parallel two-dimensional GaAs/InAs electron systems by the correlation interaction  

SciTech Connect (OSTI)

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

455

Epitaxial growth of Cu,,In,Ga...Se2 on GaAs,,110... and A. Rockett  

E-Print Network [OSTI]

. INTRODUCTION The Cu(In, Ga)Se2 CIGS absorber layer in a recent record-efficiency CIGS solar cell1 has a 220.13 Commercially supplied ``epi-ready'' liquid- encapsulated Czo

Rockett, Angus

456

Reducing the efficiency droop by lateral carrier confinement in InGaN/GaN quantum-well nanorods  

E-Print Network [OSTI]

Efficiency droop is a major obstacle facing high-power application of InGaN/GaN quantum-well (QW) light-emitting diodes. In this letter, we report the suppression of efficiency droop induced by density-activated defect recombination in nanorod structure of a-plane InGaN/GaN QWs. In the high carrier density regime, the retained emission efficiency in a dry-etched nanorod sample is observed to be over two times higher than that in its parent QW sample. We further argue that the improvement is a combined effect of the amendment contributed by lateral carrier confinement and the deterioration made by surface trapping.

Shi, Chentian; Yang, Fan; Park, Min Joo; Kwak, Joon Seop; Jung, Sukkoo; Choi, Yoon-Ho; Wang, Xiaoyong; Xiao, Min

2013-01-01T23:59:59.000Z

457

(12) United States Patent Harvey et al.  

E-Print Network [OSTI]

(12) United States Patent Harvey et al. (54) ANALYZING RETURN ON INVESTMENT OF ADVERTISING US 2009/0259518 Al Oct. 15,2009 Int. Cl. G06F 17/30 (2006.01) G07G 1/00 (2006.01) U.S. Cl et al. 911980 Block et al. 511982 Eskin et al. 1111982 Barber et al. 711985 Block et al. 111996

Shamos, Michael I.

458

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

459

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

460

Measurement of electron-hole friction in an n-doped GaAs/AlGaAs quantum well using optical transient-grating spectroscopy  

SciTech Connect (OSTI)

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

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

Investigation of efficiency droop for InGaN-based UV light-emitting diodes with InAlGaN barrier  

E-Print Network [OSTI]

applications in photocatalytic deodorizing such as air conditioner,1 and there have been interests in solid

462

Influence of stress on optical transitions in GaN nanorods containing a single InGaN/GaN quantum disk  

SciTech Connect (OSTI)

Cathodoluminescence (CL) hyperspectral imaging has been performed on GaN nanorods containing a single InGaN quantum disk (SQD) with controlled variations in excitation conditions. Two different nanorod diameters (200 and 280?nm) have been considered. Systematic changes in the CL spectra from the SQD were observed as the accelerating voltage of the electron beam and its position of incidence are varied. It is shown that the dominant optical transition in the SQD varies across the nanorod as a result of interplay between the contributions of the deformation potential and the quantum-confined Stark effect to the transition energy as consequence of radial variation in the pseudomorphic strain.

Zhuang, Y. D.; Shields, P. A.; Allsopp, D. W. E., E-mail: d.allsopp@bath.ac.uk [Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY (United Kingdom); Bruckbauer, J.; Edwards, P. R.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2014-11-07T23:59:59.000Z

463

The first principle study of Ni{sub 2}ScGa and Ni{sub 2}TiGa  

SciTech Connect (OSTI)

We computed the electronic structure, elastic moduli, vibrational properties, and Ni{sub 2}TiGa and Ni{sub 2}ScGa alloys in the cubic L2{sub 1} structure. The obtained equilibrium lattice constants of these alloys are in good agreement with available data. In cubic systems, there are three independent elastic constants, namely C{sub 11}, C{sub 12} and C{sub 44}. We calculated elastic constants in L2{sub 1} structure for Ni{sub 2}TiGa and Ni{sub 2}ScGa using the energy-strain method. The electronic band structure, total and partial density of states for these alloys were investigated within density functional theory using the plane-wave pseudopotential method implemented in Quantum-Espresso program package. From band structure, total and projected density of states, we observed metallic characters of these compounds. The electronic calculation indicate that the predominant contributions of the density of states at Fermi level come from the Ni 3d states and Sc 3d states for Ni{sub 2}TiGa, Ni 3d states and Sc 3d states for Ni{sub 2}ScGa. The computed density of states at Fermi energy are 2.22 states/eV Cell for Ni{sub 2}TiGa, 0.76 states/eV Cell for Ni{sub 2}ScGa. The vibrational properties were obtained using a linear response in the framework at the density functional perturbation theory. For the alloys, the results show that the L2{sub 1} phase is unstable since the phonon calculations have imagine modes.

zduran, Mustafa [Ahi Evran niversitesi Fen Edebiyat Fakltesi Fizik Blm, K?r?ehir (Turkey); Turgut, Kemal [Yksek Lisans ?rencisi, K?r?ehir (Turkey); Arikan, Nihat [Ahi Evran niversitesi E?itim Fakltesi ?lk?retim Blm, K?r?ehir (Turkey); ?yigr, Ahmet; Candan, Abdullah [Ahi Evran niversitesi Merkezi Ara?t?rma Laboratuvar?, K?r?ehir (Turkey)

2014-10-06T23:59:59.000Z

464

Reduced lattice temperature high-speed operation of pseudomorphic InGaAdGaAs field-effect transistors  

E-Print Network [OSTI]

,um GaAs buffer, 170 A Ino.zGao,sAs strained channel, 50 A undoped Ale,,,Ga,,,As undoped spacer, S dimensions of 0.25 x 200 pm and 0.5 X 200 pm with a source-drain spacing of 2 ,um. The MODFETs have gate dimensions of 0.35~ 100 pm and 0.47X 100 pm with a source-drain spacing of 1 ,um. The MISFETs have

Kolodzey, James

465

In Memory of Al Cameron  

E-Print Network [OSTI]

Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning element formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

John J. Cowan; James W. Truran

2006-11-27T23:59:59.000Z

466

Organometallic Vapor Phase Epitaxy of n-GaSb and n-GaInAsSb for Low Resistance Ohmic Contacts  

SciTech Connect (OSTI)

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

467

Low temperature carrier redistribution dynamics in InGaN/GaN quantum wells  

SciTech Connect (OSTI)

We have studied the carrier recombination dynamics in an InGaN/GaN multiple quantum well structure as a function of emission energy and excitation density between temperatures of 10?K and 100?K. Under relatively low levels of excitation, the photoluminescence (PL) intensity and decay time of emission on the high energy side of the luminescence spectrum decrease strongly between 10?K and 50?K. In contrast, for emission detected on the low energy side of the spectrum, the PL intensity and decay time increase over the same temperature range. These results are consistent with a thermally activated carrier redistribution process in which the (temperature dependent) average timescale for carrier transfer into or out of a localised state depends on the energy of the given state. Thus, the transfer time out of shallow, weakly localised states is considerably shorter than the arrival time into more deeply localised states. This picture is consistent with carriers hopping between localisation sites in an uncorrelated disorder potential where the density of localised states decreases with increasing localisation depth, e.g., a exponential or Gaussian distribution resulting from random alloy disorder. Under significantly higher levels of excitation, the increased occupation fraction of the localised states results in a greater average separation distance between unoccupied localised states, causing a suppression of the spectral and dynamic signatures of the hopping transfer of carriers.

Badcock, T. J., E-mail: Thomas.badcock@crl.toshiba.co.uk; Dawson, P.; Davies, M. J. [School of Physics and Astronomy, Photon Science Institute, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom); Kappers, M. J.; Massabuau, F. C.-P.; Oehler, F.; Oliver, R. A.; Humphreys, C. J. [Department of Materials Science and Metallurgy, 27 Charles Babbage Road, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

2014-03-21T23:59:59.000Z

468

Testing of ethylene propylene seals for the GA-4/GA-9 casks  

SciTech Connect (OSTI)

The primary O-ring seal of the GA-4 and GA-9 casks was tested for leakage with a full-scale mockup of the cask lid and flange. Tests were performed at temperatures of ambient, {minus}41{degrees}, 121{degrees}, and 193{degrees}C. Shim plates between the lid and flange simulated gaps caused by thermal distortion. The testing used a helium mass spectrometer leak detector (MSLD). Results showed that the primary seal was leaktight for all test conditions. Helium permeation through the seal began in 13--23 minutes for the ambient tests and in 1--2 minutes for the tests at elevated temperatures. After each test several hours of the pumping were typically required to reduce the MSLD background reading to an acceptable level for the next test, indicating that the seal had become saturated with helium. To verify that the test results showed permeation and not real leakage, several response checks were conducted in which a calibrated leak source was inserted in the detector line near the seal. When the leak source was activated the detector responded within seconds.

Boonstra, R.H.

1993-08-01T23:59:59.000Z

469

E-Print Network 3.0 - al suolo al Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

DEI CAMBIAMENTI Summary: tradizionali rimboschimenti vincoli al dissodamento aumento delle provvigioni e dei turni riduzione degli... Commissione al Consiglio e al...

470

Active region based on graded-gap InGaN/GaN superlattices for high-power 440- to 470-nm light-emitting diodes  

SciTech Connect (OSTI)

The structural and optical properties of light-emitting diode structures with an active region based on ultrathin InGaN quantum wells limited by short-period InGaN/GaN superlattices from both sides have been investigated. The dependences of the external quantum efficiency on the active region design are analyzed. It is shown that the use of InGaN/GaN structures as limiting graded-gap short-period superlattices may significantly increase the quantum efficiency.

Tsatsulnikov, A. F., E-mail: Andrew@beam.ioffe.ru; Lundin, W. V.; Sakharov, A. V.; Zavarin, E. E.; Usov, S. O.; Nikolaev, A. E.; Cherkashin, N. A.; Ber, B. Ya.; Kazantsev, D. Yu. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation); Mizerov, M. N. [Russian Academy of Sciences, Center for Microelectronics, Ioffe Physicotechnical Institute (Russian Federation); Park, Hee Seok [Samsung Electro-Mechanics Co. Ltd. (Korea, Republic of); Hytch, M.; Hue, F. [National Center for Scientific Research, Center for Material Elaboration and Structural Studies (France)

2010-01-15T23:59:59.000Z

471

Course Syllabus: Chemistry 3AL Course Information  

E-Print Network [OSTI]

Course Syllabus: Chemistry 3AL Course Information Course Name Chemistry 3AL Course Instructor are online. Chemistry 3AL Syllabus https://elearning.berkeley.edu/AngelUploads/Content/2013SUC... 1 of 5 5

Alvarez-Cohen, Lisa

472

Maskless lateral epitaxial overgrowth of GaN on sapphire  

SciTech Connect (OSTI)

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

473

Pulsed laser annealing of Be-implanted GaN  

SciTech Connect (OSTI)

Postimplantation thermal processing of Be in molecular-beam-epitaxy-grown GaN by rapid thermal annealing (RTA) and pulsed laser annealing (PLA) was investigated. It has been found that the activation of Be dopants and the repair of implantation-induced defects in GaN films cannot be achieved efficiently by conventional RTA alone. On the other hand, good dopant activation and surface morphology and quality were obtained when the Be-implanted GaN film was annealed by PLA with a 248 nm KrF excimer laser. However, observations of off-resonant micro-Raman and high-resolution x-ray-diffraction spectra indicated that crystal defects and strain resulting from Be implantation were still existent after PLA, which probably degraded the carrier mobility and limited the activation efficiency to some extent. This can be attributed to the shallow penetration depth of the 248 nm laser in GaN, which only repaired the crystal defects in a thin near-surface layer, while the deeper defects were not annealed out well. This situation was significantly improved when the Be-implanted GaN was subjected to a combined process of PLA followed by RTA, which produced good activation of the dopants, good surface morphology, and repaired bulk and surface defects well.

Wang, H.T.; Tan, L.S.; Chor, E.F. [Centre for Optoelectronics, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

2005-11-01T23:59:59.000Z

474

22209_HPC_cvr_FL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience hands-onASTROPHYSICS H.CarbonMarch Value of the

475

ALS Ceramics Materials Research Advances Engine Performance  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ALS Ceramics Materials Research Advances Engine Performance ALS Ceramics Materials Research Advances Engine Performance Print Thursday, 27 September 2012 00:00 ritchie ceramics...

476

AlN/Fe/AlN nanostructures for magnetooptic magnetometry  

SciTech Connect (OSTI)

AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of ??=?410?nm (3.02?eV) and operate at oblique light incidence angles, ?{sup (0)}, to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at ?{sup (0)}???5 and longitudinal Kerr effect spectra (?{sup (0)}?=?45) at photon energies between 1 and 5?eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

Likov-Jakubisov, E., E-mail: liskova@karlov.mff.cuni.cz; Vi?ovsk, . [Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); irok, P.; Hrabovsk, D.; Pitora, J. [Nanotechnology Center, Technical University of Ostrava, 17. listopadu 15/2172, 70833 Ostrava Poruba (Czech Republic); Harward, I.; Celinski, Z. [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy., Colorado Springs, Colorado 80918 (United States)

2014-05-07T23:59:59.000Z

477

A nuclear magnetic resonance probe of Fe-Al and Al20V2Eu intermetallics  

E-Print Network [OSTI]

Al-rich Fe-Al systems (FeAl2, Fe2 Al5 and Fe4Al13) and Al20V2Eu have complicated structures with quasicrystal-like features making these materials potentially of interest for magnetic behavior. However, there is not much work on these materials...

Chi, Ji

2009-05-15T23:59:59.000Z

478

AL2007-03.doc  

Office of Environmental Management (EM)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "of EnergyEnergy Cooperation |South Valley ResponsibleSubmissionofDepartmentNo. AL7.pdf6-04v2.pdfContractorAL

479

ALS Evidence Confirms Combustion Theory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience4AJ01) (See95TI07)Operations DuringALS Doctoral Fellowship inALS

480

ALS Scientific Advisory Committee Charter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

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481

ALS Scientific Advisory Committee Charter  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience4AJ01) (See95TI07)Operations DuringALS DoctoralALS RevealsScientific