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1

SF6432-CN Construction  

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

7/31/13 7/31/13 Page 1 of 31 Printed copies of this document are uncontrolled. Retrieve latest version electronically. SANDIA CORPORATION SF 6432-CN (07/2013) Section II STANDARD TERMS AND CONDITIONS FOR FIRM-FIXED PRICE COMMERCIAL CONSTRUCTION CONTRACTS THE FOLLOWING CLAUSES APPLY TO THIS CONTRACT AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY SUPPLEMENTED OR AMENDED IN WRITING IN THE COVER PAGE OR SECTION I. (CTRL+CLICK ON A LINK BELOW TO ADVANCE DIRECTLY TO THAT SECTION) ACCEPTANCE OF TERMS AND CONDITIONS (Ts&Cs) APPLICABLE LAW ASSIGNMENT AUTHORIZED DISTRIBUTORS BANKRUPTCY CANCELLATION OR TERMINATION FOR CONVENIENCE CHANGES COMPLIANCE WITH LAWS DEFINITIONS DIFFERING SITE CONDITIONS DISPUTES

2

CnLrJGD  

Office of Legacy Management (LM)

l&o-1760 l&o-1760 CnLrJGD 8CURCEN4%4UALLfCE!8SE Licenee Bo. c-3862 tnted: J. T. Baker Chemical Compfuq Phillipsburg, New Jersey Attention: Mr. Joseph L. MetcenQrf Osntlewn: Rvsunnt to the Attalc &orgy Act of 1954 au4 Section 40.21 of t& &&e of Federal Negulationr, Title 10 Control of &urea Matsrial, -Atomic !Znergy, Chapter 1, part40 - P me hereby llc need to nc lve poere of and title to up to one ld ogrem of urai~~ t t&SIG gradef for use slou R etndier on the pmparatlon of sodium diurenetar You are further liceneed-~~tnmef~~~~~-Qe~i~r-~~~e~:lq?l of an& title to refined source maataried to any pereon licensed. by the Atalc Baergy ~emionj within the llmlte of his license. ?hie llccnee fe eubject to all the provieione of the Atopic Energy Act of

3

CN vibration–rotation spectrum  

Science Journals Connector (OSTI)

CN vibration–rotation bands for the sequences (1–0) through (4–3) and (2–0) through (4–2) were observed in a King furnace and measured in the spectral regions 1797–2208 and 3740–4156...

Davis, Sumner P; Brault, James W; Abrams, Mark C; Rao, M L P

1991-01-01T23:59:59.000Z

4

Reduction of Hg(II) to Hg(0) by Magnetite. | EMSL  

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

of Hg(II) to Hg(0) by Magnetite. Reduction of Hg(II) to Hg(0) by Magnetite. Abstract: Mercury (Hg) is a highly toxic element, and its contamination of groundwater presents a...

5

Hg System Assembly and Testing Status  

E-Print Network [OSTI]

#12;2VRVS Meeting 8 Nov 2006 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Hg Drain & Spill Ports Completed Hg drain from cylinder Hg leak sump with float switch Hg spill extraction port #12;3VRVS Meeting 8 Nov 2006 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Local Hg Vapor Filters · Hg

McDonald, Kirk

6

Hg Delivery System Vacuum 25 Oct 2005  

E-Print Network [OSTI]

. S. DEPARTMENT OF ENERGY V. Graves 25 Oct 2005 MERIT Mtg at MIT Oct 17-19 · During Hg delivery system to both design and operations #12;3 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY V. Graves 25 & return lines - Sump tank & all connecting ports - Hg cylinder & bellows Hg inlet Hg cylinder & Bellows

McDonald, Kirk

7

Capturing inhomogeneous broadening of the -CN stretch vibration...  

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

Capturing inhomogeneous broadening of the -CN stretch vibration in a Langmuir monolayer with high-resolution spectra and Capturing inhomogeneous broadening of the -CN stretch...

8

MERIT Hg System Fabrication Status  

E-Print Network [OSTI]

LABORATORY U. S. DEPARTMENT OF ENERGY MC Friday Meeting 13 Jan 2006 Syringe Pump · Consists of 3 hydraulic cylinders, hydraulic pump, and manual controls · Awarded to Airline Hydraulics Corporation (AHC - Hg system cart - Magnet elevation beam · Bids currently being obtained from Oak Ridge & Princeton

McDonald, Kirk

9

MERIT Hg System Design Update  

E-Print Network [OSTI]

tank · Multiple Hg cylinder ports #12;4 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY MERIT Princeton University Nov 17-18, 2005 #12;2 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY MERIT distortion #12;3 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY MERIT Collab. Mtg Nov 17-18, 2005

McDonald, Kirk

10

MERIT Hg System Final Design Review  

E-Print Network [OSTI]

MERIT Hg System Final Design Review Hg Target System Operations V.B. Graves P.T. Spampinato T Facility Constraints · No overhead lifting capability within tunnel · Modularity required - Component 2 (In- beam) · Baseplate & magnet will go in beam line prior to Hg system · Blocks under magnet end

McDonald, Kirk

11

The CnC Programmimg Model Zoran Budimlic1  

E-Print Network [OSTI]

The CnC Programmimg Model Zoran Budimli´c1 Michael Burke1 Vincent Cav´e1 Kathleen Knobe2 Geoff Rice University 2 Intel Corporation 3 UCLA Abstract We introduce the Concurrent Collections (CnC) programming model. CnC supports flexible combinations of task and data parallelism while retaining determinism

Palsberg, Jens

12

CnC-CUDA: Declarative Programming for GPUs  

Science Journals Connector (OSTI)

In this paper, we extend past work on Intel’s Concurrent Collections (CnC) programming model to address the hybrid programming challenge using a model called CnC-CUDA. CnC is a declarative and implicitly parallel...

Max Grossman; Alina Simion Sbîrlea…

2011-01-01T23:59:59.000Z

13

Target System Operations and Hg Handling  

E-Print Network [OSTI]

CERN June 19-20, 2006 #12;2 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Hg System Safety RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Hg System Safety Review 19-20 June 2006 Containment/vent ports will be soap- bubble checked Primary Enclosure Secondary Enclosure #12;4 OAK RIDGE NATIONAL

McDonald, Kirk

14

Microsoft Word - HgAcBr  

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

August 2013 August 2013 Quantification of the Mercury Adsorption Mechanism on Brominated Activated Carbon The primary anthropogenic source of mercury (Hg) emissions into the atmosphere is coal- fired power utilities. This work explores materials designed for Hg capture to be applied in the ductwork of a power plant to prevent Hg release into the atmosphere. Bench-scale com- bustion experiments have been carried out, in which sorbent materials were placed in a simulated flue gas stream doped with ppb levels of Hg. The sorbent surfaces were probed using x-ray absorption spectroscopy to determine the mechanism of Hg binding and to ultimately improve solvent design. The spectroscopy data was analyzed alongside results from density functional theory (DFT) for benchmarking so that DFT can be used as a

15

Experimental and theoretical study of neutral AlmCn and AlmCnHx clusters  

E-Print Network [OSTI]

a number of low lying isomeric structures. Introduction Metal carbide clusters have been extensively mechanisms for these special structures, geometric structures of metal carbide clusters have been transition metals, respectively. They found that the geometric structures of Co2Cn Ã? clusters exhibit

Rocca, Jorge J.

16

Infrared spectra of ClCN{sup +}, ClNC{sup +}, and BrCN{sup +} trapped in solid neon  

SciTech Connect (OSTI)

When a mixture of ClCN or BrCN with a large excess of neon is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, the infrared spectrum of the resulting solid includes prominent absorptions of the uncharged isocyanide, ClNC or BrNC, and of the corresponding cation, ClCN{sup +} or BrCN{sup +}. The NC-stretching fundamentals of the isocyanides trapped in solid neon lie close to the positions for their previously reported argon-matrix counterparts. The CN-stretching absorptions of ClCN{sup +} and BrCN{sup +} and the CCl-stretching absorption of ClCN{sup +} appear very close to the gas-phase band centers. Absorptions of two overtones and one combination band of ClCN{sup +} are identified. Reversible photoisomerization of ClCN{sup +} to ClNC{sup +} occurs. The two stretching vibrational fundamentals and several infrared and near infrared absorptions associated with electronic transitions of ClNC{sup +} are observed. Minor infrared peaks are attributed to the vibrational fundamental absorptions of the CX and CX{sup +} species (X=Cl,Br)

Jacox, Marilyn E.; Thompson, Warren E. [Optical Technology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441 (United States)

2007-06-28T23:59:59.000Z

17

The unimolecular reaction of isolated CF3CN: Energy disposal into CN product degrees of freedom  

Science Journals Connector (OSTI)

Measurements of nascent CN rovibronic state distributions following the unimolecular reaction CF3CN?CF3+CN are reported. Excitation under collision?free conditions is provided by IR multiple photon excitation using the focused output from a CO2?TEA laser and therefore reaction occurs from a range of energiesE ? centered at some value which is determined by the laser intensity. Nascent reaction products are detected by laser induced fluorescence(LIF) and by exciting the ?v = 0 ?1 and ?2 sequences of the B? 2?+?X? 2?+ system rotational distributions can be determined for v ? = 0 1 and 2 with no interference. Rotational excitation in v ? = 0–2 is the same for each v ? and can be described by a Boltzmann distribution with T R = 1200±100 K. Product translational energies are estimated by monitoring LIF intensities as a function of the delay between the onsets of the CO2 and dye laser pulses. Translational energies do not change over the range v ? = 0–4 and can be ascribed a temperature of 850±150 K. CN vibrational excitation is determined by simulating the LIF spectra and can be described by T V = 2400±150 K based on v ? = 0–3 with v ? = 4 barely detectable. These results can be explained qualitatively using a statistically based model in which the CN vibration acts as a thermometer of parent excitation and where parent nuclear motions including vibrations as well as motions n o t influenced by potential energy are in equilibrium at the transition state. The constancy of rotational and translational excitations with respect to v ? are seen to derive from the range of E ? from which dissociation occurs.

F. Kong; A. M. Renlund; C. Wittig

1982-01-01T23:59:59.000Z

18

Isomorphism testing for circulant graphs Cn(a, b)  

E-Print Network [OSTI]

Isomorphism testing for circulant graphs Cn(a, b). Sara Nicoloso ?. Ugo Pietropaoli †. March 10, 2010. Abstract. In this paper we focus on connected ...

2010-03-10T23:59:59.000Z

19

%'&)( 021)3#0&)(4 57698A@CBEDF8HG$IPDRQDF8A@CBSG$ITDRUVUWDX`Y9U$GaQ9bc@d'efDUWD9Ghg2D9IpicIT@q@gsrCGaQDt8AYFuvDQRr  

E-Print Network [OSTI]

@¦d'efD¦UWD9Ghg2D9IpicIT@q@¦gsrCGaQ¦Dt8AYFuvD¦QRr bwY9Q¦Y9g¨DF8HGx@CQy@¦dp@CUa6wBEYFu@¦dGaQ98AY9g¨YFuA8tGWD8i

Nielsen, Finn Ã?rup

20

Hg System Status V.B. Graves  

E-Print Network [OSTI]

· Hydraulic power unit (HPU) and syringe cylinders delivered to ORNL July 21 - Hg cylinder discharge piping cart until secondary containment received #12;3MC Friday Meeting4 Aug 2006 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY HPU Setup · Hydraulic fluid fill and drain process developed using

McDonald, Kirk

Note: This page contains sample records for the topic "hg cn 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

Mechanism of terahertz photoconductivity in semimetallic HgTe/CdHgTe quantum wells  

SciTech Connect (OSTI)

Terahertz photoconductivity in magnetic fields in semimetallic HgTe/CdHgTe quantum wells has been studied. The main contribution to photoconductivity comes from a signal that appears as a result of electron-gas heating. It is shown that, with the cyclotron resonance conditions satisfied, the photoconductivity signal is composed of cyclotron-resonance and bolometric components. However, in this case too, the bolometric contribution predominates.

Vasilyev, Yu. B., E-mail: yu.vasilyev@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Mikhailov, N. N. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Gouider, F. [Institut fuer Angewandte Physik (Germany); Vasilyeva, G. Yu. [St. Petersburg State Polytechnic University (Russian Federation); Nachtwei, G. [Institut fuer Angewandte Physik (Germany)

2012-05-15T23:59:59.000Z

22

Sediment transport and Hg recovery in Lavaca Bay, as evaluated from radionuclide and Hg distributions  

SciTech Connect (OSTI)

Mercury was released in the late 1960s from a chloralkali facility managed by ALCOA and deposited into sediments of Lavaca Bay, TX. Sediments have recorded this event as a well-defined subsurface concentration maximum. Radionuclide, mercury, X-radiography, and grain size data from sediment cores taken in 1997 at 15 stations in Lavaca bay were used to assess sediment and Hg movements in the bay. Sediment accumulation rates were calculated from bomb fallout nuclide ({sup 137}Cs, {sup 239,240}Pu) peaks in 1963 and from the steady-state delivery of {sup 210}Pb from the atmosphere. Sedimentation rates are highest at near-shore sites near the ALCOA facility and generally decrease away from shore. Sedimentation rates in some areas are likely influenced by anthropogenic activities such as dredging. Particle reworking, as assessed from {sup 7}Be measurements, is generally restricted to the upper 2--7 cm of sediments. Numerical simulations of Hg profiles using measured sedimentation and mixing parameters indicate that at most sites high remnant mercury concentrations at 15--60 cm depth cannot supply substantial amounts of Hg to surface sediments. Assuming no future Hg supplies, Hg concentrations in surface sediments are predicted to decrease exponentially with a recovery half-time of 4 {+-} 2 years.

Santschi, P.H.; Allison, M.A.; Asbill, S.; Perlet, A.B. [Texas A and M Univ., Galveston, TX (United States)] [Texas A and M Univ., Galveston, TX (United States); Cappellino, S. [Parametrix, Inc., Houston, TX (United States)] [Parametrix, Inc., Houston, TX (United States); Dobbs, C.; McShea, L. [Aluminum Co. of America, Point Comfort, TX (United States)] [Aluminum Co. of America, Point Comfort, TX (United States)

1999-02-01T23:59:59.000Z

23

Process of [sup 196]Hg enrichment  

DOE Patents [OSTI]

A simple rate equation model shows that by increasing the length of the photochemical reactor and/or by increasing the photon intensity in said reactor, the feedstock utilization of [sup 196]Hg will be increased. Two preferred embodiments of the present invention are described, namely (1) long reactors using long photochemical lamps and vapor filters; and (2) quartz reactors with external UV reflecting films. These embodiments have each been constructed and operated, demonstrating the enhanced utilization process dictated by the mathematical model (also provided).

Grossman, M.W.; Mellor, C.E.

1993-04-27T23:59:59.000Z

24

CN/2011/SC/IHP/PI/2 Sediment Issues & Sediment  

E-Print Network [OSTI]

CN/2011/SC/IHP/PI/2 #12;Sediment Issues & Sediment Management in Large River Basins Interim Case Study Synthesis Report International Sediment Initiative Technical Documents in Hydrology UNESCO Office Sediment Initiative Core Group - Members: o Prof. Desmond Walling o Prof. Manfred Spreafico o Prof. Hu

Julien, Pierre Y.

25

Magnetism of HgSe:Fe  

Science Journals Connector (OSTI)

The perpendicular and parallel components of the magnetization of the mixed valence system Hg1-xFexSe in the strongly dilute limit (xmagnetic fields up to 20 T. In this interesting semimagnetic semiconductor the overall magnetization is caused simultaneously by Fe3+ (Brillouin paramagnet), Fe2+ (van Vleck paramagnet), and free electrons (diamagnetic de Haas-van Alphen effect). Using a torque magnetometer the various contributions with their anisotropy are individually determined. For very low iron content (xmagnetic moment perpendicular to the magnetic field when applying the field in a nonsymmetric direction of the crystal. Using recent theoretical results on the energy-level diagram of Fe2+ in the Td symmetry of a HgSe host lattice we deduce a spin-orbit level splitting of 2 meV from our experimental data. In contrast to higher concentration samples, both the Brillouin paramagnetism of Fe3+ and the van Vleck paramagnetism of Fe2+ can be attributed to the sum from individual Fe donors with no obvious magnetic interaction between them. Finally, we also have measured de Haas-van Alphen oscillations of the conduction-band electrons with amplitudes of the same order as the paramagnetic background. From the measured crystal-field-induced anisotropy in the magnetic moment we deduce a Fermi-surface anisotropy of about 7%.

U. Zeitler; A. Wittlin; J. C. Maan; W. Dobrowolski; A. Mycielski

1996-12-01T23:59:59.000Z

26

Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal  

Open Energy Info (EERE)

Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal Areas Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Hg Anomalies In Soils- A Geochemical Exploration Method For Geothermal Areas Details Activities (5) Areas (5) Regions (0) Abstract: Hg contents of soils in geothermal areas in the western U.S. were measured and a three-fold distribution was observed: peak, aureole and background. Peak values (up to several 100 ppm Hg) occur in fumaroles of vapour-dominated systems, around hot springs, and in zones overlying steeply dipping, hot-water aquifers. Aureoic values (up to several 100 ppb Hg) are found in zones surrounding the peak areas and delineate areas with shallow geothermal convection. Background values vary between 7 and 40 ppb

27

A case study of mercury and methylmercury dynamics in a Hg-contaminated municipal wastewater treatment plant  

Science Journals Connector (OSTI)

A study of total Hg (Hg) and methylmercury (MeHg) was performed in a 40 mgd capacity municipal sewage treatment plant in which elemental Hg was used as ... the Hg seals with mechanical seals. A mass balance condu...

C. C. Gilmour; N. S. Bloom

1995-02-01T23:59:59.000Z

28

A Case Study of Mercury and Methylmercury Dynamics in a Hg-Contaminated Municipal Wastewater Treatment Plant  

Science Journals Connector (OSTI)

A study of total Hg (Hg) and methylmercury (MeHg) was performed in a 40 mgd capacity municipal sewage treatment plant in which elemental Hg was used as ... the Hg seals with mechanical seals. A mass balance condu...

C. C. Gilmour; N. S. Bloom

1995-01-01T23:59:59.000Z

29

Hg L3 XANES Study of Mercury Methylation in Shredded  

E-Print Network [OSTI]

,indicatingbioaccumulationofmercury.Plantsamples collected at this site were also grown in nutrient solution with 1 ppm HgCl2 under (1) aerobic conditions

30

U01HG004279 (D.M.M.), U01HG004261 (E.L.), U01HG004274 (S.H.), and U41HG004269 (L.S.). Awards  

E-Print Network [OSTI]

.T.N.), the Indiana Genomics Initiative (T.C.K.), H. Smith and the NIDDK genomics core laboratory (B.O.), NIH R01HG

31

IP CN Crosby, ND Natural Gas Pipeline Imports From Canada (Dollars...  

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

IP CN Crosby, ND Natural Gas Pipeline Imports From Canada (Dollars per Thousand Cubic Feet) IP CN Crosby, ND Natural Gas Pipeline Imports From Canada (Dollars per Thousand Cubic...

32

Evidence of stress?mediated Hg migration in Hg1?x Cd x Te  

Science Journals Connector (OSTI)

Photoemission results from some ?110? cleaved surfaces of Hg1?x Cd x Te indicate that the Fermi level is pinned suggesting that while the bulk of the material is p type the area stressed during cleavage has been converted to n type. Electrolyte electroreflectance (EER) measurement confirmed the n?type character of the cleaved surface and showed that the alloy composition x at the surface after cleavage is high (x=0.22) compared to the bulk value (x=0.185). The high x value associated with the n character indicates that under stress the Hg migrates at least partially via the formation of donor defects. The defect density is reflected in the EER linewidth.

P. M. Raccah; U. Lee; J. A. Silberman; W. E. Spicer; J. A. Wilson

1983-01-01T23:59:59.000Z

33

Measuring the Overhead of Intel C++ CnC over TBB for Gauss-Jordan Elimination  

E-Print Network [OSTI]

Measuring the Overhead of Intel C++ CnC over TBB for Gauss-Jordan Elimination Peiyi Tang Department only by the data dependencies be- tween the tasks. Both Intel C++ Concurrent Col- lections (CnC algorithm and implemented it in TBB. We compare the performances of TBB and CnC, which is built on top

Tang, Peiyi

34

Growth of superconducting Hg-1212 very-thin films  

E-Print Network [OSTI]

High quality epitaxial HgBa2CaCu2O6+delta (Hg- High 1212) films with thickness less than 100 nm have been successfully synthesized using cation-exchange process. The films show the superconducting transition up to similar to 118 K which is close...

Wu, Judy; Xie, Y. Y.; Kang, B. W.; Gapud, A. A.; Aytug, T.; Fang, L.

1999-06-01T23:59:59.000Z

35

MEASURED ENERGY PERFORMANCE OF ENERGY-EFFICIENT NEW COMMERCIAL BUILDINGS: RESULTS FROM THE BECA-CN DATA COMPILATION  

E-Print Network [OSTI]

and energy usage for 133 buildings in the BECA-CN (Buildings Energy-Use Compilation and Analysis - part CN: New Energy-Efficient Commercial

Piette, M.A.

2010-01-01T23:59:59.000Z

36

Abundance analysis of SB2 binary stars with HgMn primaries  

E-Print Network [OSTI]

We present a short review of the abundances in the atmospheres of SB2 systems with Mercury-Manganese (HgMn) primaries. Up to now a careful study has been made for both components of 8 out of 17 known SB2 binaries with orbital periods shorter than 100 days and mass ratio ranging from 1.08 to 2.2. For all eight systems we observe a lower Mn abundance in the secondary's atmospheres than in the primary's. Significant difference in the abundances is also found for some peculiar elements such as Ga, Xe, Pt. All secondary stars with effective temperatures less than 10000 K show abundance characteristics typical of the metallic-line stars.

T. Ryabchikova

1998-05-06T23:59:59.000Z

37

CnC-CUDA: Declarative Programming for GPUs Max Grossman, Alina Simion Sb^irlea, Zoran Budimlic, and Vivek Sarkar  

E-Print Network [OSTI]

extend past work on Intel's Concurrent Collections (CnC) programming model to address the hybrid programming challenge using a model called CnC-CUDA. CnC is a declarative and implicitly par- allel determinism. CnC computations are built using steps that are related by data and control dependence edges

Budimliæ, Zoran

38

Capturing and Composing Parallel Patterns with Intel CnC Ryan Newton Frank Schlimbach Mark Hampton Kathleen Knobe  

E-Print Network [OSTI]

Capturing and Composing Parallel Patterns with Intel CnC Ryan Newton Frank Schlimbach Mark Hampton to encapsulate only a single pattern. Thus we explore the use of Intel CnC as a single frame- work for capturing. In this paper, we consider Intel Concurrent Collections (CnC)[9]. as a candidate substrate for patterns. CnC

Gummadi, Ramakrishna

39

Paleomagnetic Secular Variation (PSV), 137Cs, and Hg dating techniques  

E-Print Network [OSTI]

Portland State University Department of Geology #12;Hg-Mercury contamination dating http fission of Uranium-235 · Due to nuclear weapons testing · Highly water soluble (spreads quickly) · Half

Fountain, Andrew G.

40

Operator-Schmidt decomposition of the quantum Fourier transform on C^N1 tensor C^N2  

E-Print Network [OSTI]

Operator-Schmidt decompositions of the quantum Fourier transform on C^N1 tensor C^N2 are computed for all N1, N2 > 1. The decomposition is shown to be completely degenerate when N1 is a factor of N2 and when N1>N2. The first known special case, N1=N2=2^n, was computed by Nielsen in his study of the communication cost of computing the quantum Fourier transform of a collection of qubits equally distributed between two parties. [M. A. Nielsen, PhD Thesis, University of New Mexico (1998), Chapter 6, arXiv:quant-ph/0011036.] More generally, the special case N1=2^n1<2^n2=N2 was computed by Nielsen et. al. in their study of strength measures of quantum operations. [M.A. Nielsen et. al, (accepted for publication in Phys Rev A); arXiv:quant-ph/0208077.] Given the Schmidt decompositions presented here, it follows that in all cases the communication cost of exact computation of the quantum Fourier transform is maximal.

Jon Tyson

2002-10-13T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

Calculations of the electronic states of the HgI and HgTe molecules by the SCF-X?-SW method  

Science Journals Connector (OSTI)

The SCF-X?-SW method was used to study the electronic structure and calculate the spectroscopic constants of the HgI and HgTe molecules in the ground and excited electronic states.

V. M. Kovba; E. A. Pazyuk

2006-08-01T23:59:59.000Z

42

Mercury nonstoichiometry of the Hg1-xBa2CuO4+ superconductor and the P(Hg)-P(O2)-T phase diagram of the Hg-Ba-Cu-O system.  

E-Print Network [OSTI]

1 Mercury nonstoichiometry of the Hg1-xBa2CuO4+ superconductor and the P(Hg)-P(O2)-T phase diagram-nonstoichiometry and exists in a certain P(Hg), P(O2) and T range. Mercury nonstoichiometry of Hg-1201 was investigated in the 923 T 1095 K; 2.0 P(Hg) 8.4 atm; 0.09 P(O2) 0.86 atm ranges. It was found that the mercury

Rudnyi, Evgenii B.

43

Energy loss rate of a charged particle in HgTe/(HgTe, CdTe) quantum wells  

SciTech Connect (OSTI)

The energy loss rate (ELR) of a charged particle in a HgTe/(HgTe, CdTe) quantum well is investigated. We consider scattering of a charged particle by the bulk insulating states in this type of topological insulator. It is found that the ELR characteristics due to the intraband excitation have a linear energy dependence while those due to interband excitation depend on the energy exponentially. An interesting quantitative result is that for a large range of the incident energy, the mean inelastic scattering rate is around a few terahertz.

Chen, Qinjun; Sin Ang, Yee [School of Physics, University of Wollongong, New South Wales 2522 (Australia)] [School of Physics, University of Wollongong, New South Wales 2522 (Australia); Wang, Xiaolin [Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522 (Australia)] [Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522 (Australia); Lewis, R. A.; Zhang, Chao [School of Physics, University of Wollongong, New South Wales 2522 (Australia) [School of Physics, University of Wollongong, New South Wales 2522 (Australia); Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522 (Australia)

2013-11-04T23:59:59.000Z

44

Star formation around the mid-infrared bubble CN 148  

E-Print Network [OSTI]

We present a multi-wavelength study to analyse the star formation process associated with the mid-infrared bubble CN 148 (H II region G10.3-0.1), which harbors an O5V-O6V star. The arc-shaped distribution of molecular CO(2-1) emission, the cold dust emission, and the polycyclic aromatic hydrocarbon features trace a photodissociation region (PDR) around the H II region. We have identified 371 young stellar objects (YSOs) in the selected region and, interestingly, their spatial distribution correlates well with the PDR. 41% of these YSOs are present in 13 clusters, each having visual extinction larger than 16 mag. The clusters at the edges of the bubble (both northeast and southwest) are found to be relatively younger than the clusters located further away from the bubble. We also find that four 6.7 GHz methanol masers, two Extended Green Objects, an ultra-compact H II region, and a massive protostar candidate (as previously reported) are spatially positioned at the edges of the bubble. The existence of an appa...

Dewangan, L K; Grave, J M C; Mallick, K K

2014-01-01T23:59:59.000Z

45

Mother-embryo isotope (15 C) fractionation and mercury (Hg)  

E-Print Network [OSTI]

used to investigate the trophic ecology, foraging habitats and heavy metal contamination). Consequently, Hg concentrations are important to monitor because of the toxicity of this metal. In order of this element in muscle and liver. Key words: sharks; stable isotopes; trace metal; maternal influence. hal

Paris-Sud XI, Université de

46

On-line method of determining utilization factor in Hg-196 photochemical separation process  

DOE Patents [OSTI]

The present invention is directed to a method for determining the utilization factor [U] in a photochemical mercury enrichment process (.sup.196 Hg) by measuring relative .sup.196 Hg densities using absorption spectroscopy.

Grossman, Mark W. (Belmont, MA); Moskowitz, Philip E. (Peabody, MA)

1992-01-01T23:59:59.000Z

47

CN ANOMALIES IN THE HALO SYSTEM AND THE ORIGIN OF GLOBULAR CLUSTERS IN THE MILKY WAY  

SciTech Connect (OSTI)

We explore the kinematics and orbital properties of a sample of red giants in the halo system of the Milky Way that are thought to have formed in globular clusters based on their anomalously strong UV/blue CN bands. The orbital parameters of the CN-strong halo stars are compared to those of the inner- and outer-halo populations as described by Carollo et al., and to the orbital parameters of globular clusters with well-studied Galactic orbits. The CN-strong field stars and the globular clusters both exhibit kinematics and orbital properties similar to the inner-halo population, indicating that stripped or destroyed globular clusters could be a significant source of inner-halo field stars, and suggesting that both the CN-strong stars and the majority of globular clusters are primarily associated with this population.

Carollo, Daniela [Department of Physics and Astronomy-Astronomy, Astrophysics and Astrophotonic Research Center Macquarie University-North Ryde, 2109 NSW (Australia); Martell, Sarah L. [Australian Astronomical Observatory, North Ryde, 2109 NSW (Australia); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Freeman, Ken C., E-mail: daniela.carollo@mq.edu.au, E-mail: smartell@aao.gov.au, E-mail: beers@noao.edu, E-mail: kcf@mso.anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University and Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia)

2013-06-01T23:59:59.000Z

48

A Multi-Ligand Based Pd Catalyst for C–N Cross-Coupling Reactions  

E-Print Network [OSTI]

An alternative approach to catalyst development, which led to a Pd catalyst based on two biarylphosphine ligands for C?N cross-coupling reactions, is reported. By effectively being able to take the form of multiple catalysts ...

Fors, Brett P.

49

Abstract CN05-01: Genomics and cancer management: Mind the gap!  

Science Journals Connector (OSTI)

...2013 meeting-abstract Carcinogenesis Genomics and Epigenetics of Risk Prediction in Early Disease Genomics and Epigenetics of Risk Prediction in...National Harbor, MD Abstract CN05-01: Genomics and cancer management: Mind the gap...

Janusz A. Jankowski

2013-11-01T23:59:59.000Z

50

Characterization of isothermal vapor phase epitaxial (Hg,Cd)Te  

Science Journals Connector (OSTI)

We report on the characterization of mercury cadmium telluride (Hg 1?x Cd x Te) film grown by the isothermal vapor phase epitaxial method (ISOVPE) and on the surface conversion of bulk Hg 1?xCd x Te to larger bandgap material. The crystal perfection is evaluated using defect etching electron beam and electrolyte electroreflectance (EBER and EER) and Rutherford backscattering spectrometry (RBS). Hall measurements are used to measure carrier densities and mobilities. Surface concentrations and concentration profiles are measured for the ISOVPE grown layers by transmission Fourier transform infrared spectroscopy (FTIR) and electron?probe microanalysis (EPMA) to establish quantitative informations about composition control. Metal–insulator?semiconductor (MIS) structures were made and the properties important to device performance such as compositional uniformity storage time and carrier concentration are measured. The ISOVPE layers are compared in quality to films grown by other methods and show promise for MIS devices.

S. B. Lee; L. K. Magel; M. F. S. Tang; D. A. Stevenson; J. H. Tregilgas; M. W. Goodwin; R. L. Strong

1990-01-01T23:59:59.000Z

51

Anthropogenic and Natural Emissions of Mercury (Hg) in the northeastern United Jeffrey MacAdam Sigler  

E-Print Network [OSTI]

Abstract Anthropogenic and Natural Emissions of Mercury (Hg) in the northeastern United States impact may depend on the emission rate. Anthropogenic Hg emissions in the United States are poorly characterized. Natural Hg emissions are poorly understood worldwide, due to lack of data or measurement systems

Lee, Xuhui

52

A vareity of Hg capture solutions are available  

SciTech Connect (OSTI)

While vacating the Clean Air Mercury Rule (CAMR) has postponed implementation of capturing mercury emitted by coal-fired power plants improvements in ways to capture and monitor mercury have continued. One method of enhancing Hg capture from FGD and SCR is to treat the coal by adding a halogen, such as calcium bromide in Alstom's KNX process prior to combustion. Power plants without FGD usually use sorbent injection, mostly an activated carbon, upstream of a particulate control device. 1 fig.

Blankinship, S.

2009-06-15T23:59:59.000Z

53

Reactions of the CN Radical with Benzene and Toluene: Product Detection and Low-Temperature Kinetics  

SciTech Connect (OSTI)

Low temperature rate coefficients are measured for the CN + benzene and CN + toluene reactions using the pulsed Laval nozzle expansion technique coupled with laser-induced fluorescence detection. The CN + benzene reaction rate coefficient at 105, 165 and 295 K is found to be relatively constant over this temperature range, 3.9 - 4.9 x 10-10 cm3 molecule-1 s-1. These rapid kinetics, along with the observed negligible temperature dependence, are consistent with a barrierless reaction entrance channel and reaction efficiencies approaching unity. The CN + toluene reaction is measured to have a slower rate coefficient of 1.3 x 10-10 cm3 molecule-1 s-1 at 105 K. At room temperature, non-exponential decay profiles are observed for this reaction that may suggest significant back-dissociation of intermediate complexes. In separate experiments, the products of these reactions are probed at room temperature using synchrotron VUV photoionization mass spectrometry. For CN + benzene, cyanobenzene (C6H5CN) is the only product recorded with no detectable evidence for a C6H5 + HCN product channel. In the case of CN + toluene, cyanotoluene (NCC6H4CH3) constitutes the only detected product. It is not possible to differentiate among the ortho, meta and para isomers of cyanotoluene because of their similar ionization energies and the ~;; 40 meV photon energy resolution of the experiment. There is no significant detection of benzyl radicals (C6H5CH2) that would suggest a H-abstraction or a HCN elimination channel is prominent at these conditions. As both reactions are measured to be rapid at 105 K, appearing to have barrierless entrance channels, it follows that they will proceed efficiently at the temperatures of Saturn?s moon Titan (~;;100 K) and are also likely to proceed at the temperature of interstellar clouds (10-20 K).

Trevitt, Adam J.; Goulay, Fabien; Taatjes, Craig A.; Osborn, David L.; Leone, Stephen R.

2009-12-23T23:59:59.000Z

54

Discovery of HgCu-bearing metal-sulfide assemblages in a primitive H-3 chondrite: Towards a new insight in early solar system processes  

E-Print Network [OSTI]

Mercury (Hg) is the most volatile non-gaseous element. The Hg solar abundance (Lodders, 2003; Lodders et

Ma, Chi

55

Microsoft PowerPoint - AWMA2006_Hg Panel_FEELEY.ppt  

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

A&WMA's A&WMA's 99 th Annual Conference & Exhibition Hg Control Technology Panel June 23, 2006 New Orleans, Louisiana Thomas J. Feeley, III thomas.feeley@netl.doe.gov National Energy Technology Laboratory AWMA2006_Hg Panel_FEELEY Outline * Background * Phase II project update/Phase III project descriptions * BOP and related technical issues * Preliminary economic assessment * Byproduct-Hg issues/potential economic impacts * Conclusion AWMA2006_Hg Panel_FEELEY Mercury Control Technology Program Performance/Cost Objectives * Have technologies ready for commercial demonstration by: * 2007 that can reduce "uncontrolled" Hg emissions by 50-70% * 2010 for all coals that can reduce "uncontrolled" Hg emissions by +90% * Reduce cost by 25-50% compared to baseline cost

56

HG ADSORBER (ITEM 7) ATTACHED TO SIDE WALL OF CONTAINMENT BOX  

E-Print Network [OSTI]

1 NOTE: HG ADSORBER (ITEM 7) ATTACHED TO SIDE WALL OF CONTAINMENT BOX WITH SS STRAPS. FLEX TUBING CONNECTS ADSORBER TO SUMP TANK CHKVALVE AND LID-MOUNTED FILTER 5 3 2 7 4 6 1 --- PRIMARY CONTAINMENT ASSY SHCS - 5/8-11 x 1.00 N/A 6 1 hg adsorber hjt --- KOBY HG ADSORBER, MF-2JKCB, PROVIDED BY PRINCETON N

McDonald, Kirk

57

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...

58

GaN High Power Devices  

SciTech Connect (OSTI)

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

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

2000-07-17T23:59:59.000Z

59

Safety Bulletin 2005-08: Safe Management of Mercury (Hg)  

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

SAFETY & HEALTH SAFETY & HEALTH SAFETY & HEALTH BULLETIN Assistant Secretary for Environment, Safety & Health * U.S. Department of Energy * Washington, DC 20585 Safe Management of Mercury (Hg) DOE/EH-0697 Issue No. 2005-08 June 2005 PURPOSE This Bulletin provides information on a safety concern that may impact operations at Department of Energy (DOE) facilities. Specifically, the concern is the safe handling of mercury and mercury compounds. BACKGROUND Mercury is found in small amounts in thermometers, manometers, and barometers and in larger quantities at DOE facilities - ranging from amounts found in scientific equipment to tons in remediation waste at burial sites and hundreds of tons at the DOE stockpile storage facility in Oak Ridge.

60

IAEA-CN-80/66 ISOTOPE TRACERS IN GLOBAL WATER AND CLIMATE STUDIES  

E-Print Network [OSTI]

comprehensive source of data for evaluating the modern global isotope field generated by atmospheric generalIAEA-CN-80/66 ISOTOPE TRACERS IN GLOBAL WATER AND CLIMATE STUDIES OF THE PAST AND PRESENT T Agency, Wagramer Strasse 5, P.O. Box 100, A-1400 Vienna, AUSTRIA Abstract ISOTOPE TRACERS IN GLOBAL WATER

Edwards, Thomas W.D.

Note: This page contains sample records for the topic "hg cn ga" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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61

Dating the Glass Lake Dugout by Dendrochronology (NY State Museum #CN-37516)  

E-Print Network [OSTI]

Dating the Glass Lake Dugout by Dendrochronology (NY State Museum #CN-37516) Carol Griggs, Dendrochronology Lab, Cornell University, cbg4@cornell.edu The Glass Lake Dugout was found at the bottom of Glass for the Glass Lake Dugout (Figure 2B). The series was compared with other site and regional white pine

Manning, Sturt

62

Category:Savannah, GA | Open Energy Information  

Open Energy Info (EERE)

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

63

Category:Atlanta, GA | Open Energy Information  

Open Energy Info (EERE)

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

64

GA SNC Solar | Open Energy Information  

Open Energy Info (EERE)

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

65

nTOF11 Hg System Design Tony Gabriel, Phil Spampinato  

E-Print Network [OSTI]

Presented at Berkeley Collaboration Meeting · Hg piston pump actuated by dual hydraulic cylinders · Hg delivery system size reduction - Target cart design optimization - Magnet base support #12;6 OAK RIDGE · Reduced length · Changed sump design · Refined cart details #12;7 OAK RIDGE NATIONAL LABORATORY U. S

McDonald, Kirk

66

A measurement of the neutron to 199Hg magnetic moment ratio  

E-Print Network [OSTI]

The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result $\\gamma_{\\rm n}/\\gamma_{\\rm Hg} = 3.8424574(30)$.

Afach, S; Ban, G; Bison, G; Bodek, K; Burghoff, M; Chowdhuri, Z; Daum, M; Fertl, M; Franke, B; Geltenbort, P; Green, K; van der Grinten, M G D; Grujic, Z; Harris, P G; Heil, W; Hélaine, V; Henneck, R; Horras, M; Iaydjiev, P; Ivanov, S N; Kasprzak, M; Kermaïdic, Y; Kirch, K; Knecht, A; Koch, H -C; Krempel, J; Ku?niak, M; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Naviliat-Cuncic, O; Pendlebury, J M; Perkowski, M; Pierre, E; Piegsa, F M; Pignol, G; Prashanth, P N; Quéméner, G; Rebreyend, D; Ries, D; Roccia, S; Schmidt-Wellenburg, P; Schnabel, A; Severijns, N; Shiers, D; Smith, K F; Voigt, J; Weis, A

2014-01-01T23:59:59.000Z

67

INELASTIC NEUTRON SCATTERING SELECTION RULES OF 03B1 HgI2 M. SIESKIND  

E-Print Network [OSTI]

899 INELASTIC NEUTRON SCATTERING SELECTION RULES OF 03B1 HgI2 M. SIESKIND Laboratoire de The inelastic neutron scattering selection rules of 03B1 HgI2 in the directions 0394, 03A3 and 039B are derived Abstracts 63.20D Introduction. - Inelastic neutron scattering is a powerful technique for the determination

Boyer, Edmond

68

Pb(II) and Hg(II) binding to $de$ $novo$ designed proteins studied by $^{204m}$Pb- and $^{199m}$Hg-Perturbed Angular Correlation of $\\gamma$-rays (PAC) spectroscopy Clues to heavy metal toxicity  

E-Print Network [OSTI]

Pb(II) and Hg(II) binding to $de$ $novo$ designed proteins studied by $^{204m}$Pb- and $^{199m}$Hg-Perturbed Angular Correlation of $\\gamma$-rays (PAC) spectroscopy

CERN. Geneva. ISOLDE and Neutron Time-of-Flight Experiments Committee; Correia, J G

2006-01-01T23:59:59.000Z

69

Beta decay of Ga-62  

E-Print Network [OSTI]

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

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

2003-01-01T23:59:59.000Z

70

Anomalous Stoichiometry Layered Structure and Magnetic Ordering of the Prussian Blue Analog [NEt4]2MnII3(CN)8  

SciTech Connect (OSTI)

Atypical of Prussian blue structured materials, Mn{sup II} and [NEt{sub 4}]CN react to form [NEt{sub 4}]{sub 2}Mn{sub 3}(CN){sub 8} possessing layers of octahedral [Mn{sup II}(CN){sub 6}]{sup 4-} bonded to two high-spin tetrahedral Mn{sup II} sites.

J Her; P Stephens; C Kareis; J Moore; J Miller

2011-12-31T23:59:59.000Z

71

Mercury (Hg) mineral evolution: A mineralogical record of supercontinent assembly, changing ocean geochemistry, and the emerging terrestrial biosphere  

Science Journals Connector (OSTI)

...Almaden district (primary mineralization 427-380 Ma) led to at least one additional pulse of hydrothermal Hg...chlor-alkali industry; and a new generation of compact fluorescent light bulbs. Burning of Hg-enriched coal and petroleum adds...

Robert M. Hazen; Joshua Golden; Robert T. Downs; Grethe Hystad; Edward S. Grew; David Azzolini; Dimitri A. Sverjensky

72

Angle-resolved photoemission spectroscopy study of HgBa[subscript 2]CuO[subscript 4+?  

E-Print Network [OSTI]

HgBa[subscript 2]CuO[subscript 4+?]. (Hg1201) has been shown to be a model cuprate for scattering, optical, and transport experiments, but angle-resolved photoemission spectroscopy (ARPES) data are still lacking owing to ...

Chan, M. K.

73

SF 6432-CN Standard Terms and Conditions for Fixed Price Commercial Construction  

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

CN (04-95) CN (04-95) Sections II & III SECTION II STANDARD TERMS AND CONDITIONS FOR FIXED PRICE CONSTRUCTION CONTRACTS INDEX OF CLAUSES THE FOLLOWING CLAUSES APPLY TO THIS REQUEST FOR QUOTATION AND CONTRACT AS INDICATED UNLESS SPECIFICALLY DELETED, OR EXCEPT TO THE EXTENT THEY ARE SPECIFICALLY SUPPLEMENTED OR AMENDED IN WRITING IN THE SIGNATURE PAGE OR SECTION I. No. Title Page "A" Clauses apply to Requests for Quotation and Contracts at any value. A10 Definitions 3 A11 Unclassified Contract 3 A12 Assignment 3 *A13 Releases Void 3 *A14 Notice of Labor Disputes 3 *A15 Delivery of Excess Quantities $250 or less 3 *A16 Contractor's Information 3 A17 Delegated Representatives 3 *A18 Defense Priority and Allocation 3 Requirements A19 Terms and Conditions 4

74

Palladium-catalyzed C-N cross-coupling reactions toward the synthesis of drug-like molecules  

E-Print Network [OSTI]

The development of methodologies for C-N bond formation reactions is an important scientific challenge because of many academic and industrial applications. This work will focus particularly on palladium-catalyzed ...

McAvoy, Camille Z

2012-01-01T23:59:59.000Z

75

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

SciTech Connect (OSTI)

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

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

2010-10-14T23:59:59.000Z

76

DETECTION OF FeCN (X {sup 4}{Delta}{sub i} ) IN IRC+10216: A NEW INTERSTELLAR MOLECULE  

SciTech Connect (OSTI)

A new interstellar molecule, FeCN (X {sup 4}{Delta}{sub i} ), has been detected in the envelope of the carbon-rich asymptotic giant branch star, IRC+10216. This work is the first definitive detection of an iron-bearing molecule in the interstellar medium and is based on newly measured rest frequencies. Eight successive rotational transitions of this linear free radical in the lowest spin ladder, {Omega} = 7/2, were observed at 2 and 3 mm using the Arizona Radio Observatory (ARO) 12 m telescope. Three transitions appear as single, unblended features at the 1-2 mK level and exhibit characteristic IRC+10216 line profiles; one had previously been observed with the IRAM 30 m telescope. Two other transitions are partially blended, but exhibit distinct emission at the FeCN frequencies. The remaining transitions are either completely contaminated, or are too high in energy. Comparison of the ARO and IRAM data suggests a source size for FeCN of {approx}30'' in IRC+10216, indicating an outer shell distribution, as expected for a free radical. The column density derived for FeCN is N{sub tot} = 8.6 x 10{sup 11} cm{sup -2} with a rotational temperature of T{sub rot} = 21 K. The fractional abundance of this molecule is [FeCN]/[H{sub 2}] {approx} 2-7 x 10{sup -10}-comparable to that of MgCN and KCN in IRC+10216. FeCN is likely formed by gas-phase reactions of Fe{sup +} or neutral iron; the latter has a significant gas-phase abundance in the outer shell. The detection of FeCN is further evidence that metal cyanides/isocyanides dominate the chemistry of refractory elements in IRC+10216.

Zack, L. N.; Halfen, D. T.; Ziurys, L. M. [Department of Chemistry, University of Arizona, P.O. Box 210041, 1306 East University Boulevard, Tucson, AZ 85721 (United States)

2011-06-01T23:59:59.000Z

77

Shape coexistence in {sup 180}Hg studied through the {beta} decay of {sup 180}Tl  

SciTech Connect (OSTI)

The {beta}{sup +}/EC decay of {sup 180}Tl and excited states in the daughter nucleus {sup 180}Hg have been investigated at the CERN On-Line Isotope Mass Separator (ISOLDE) facility. Many new low-lying energy levels were observed in {sup 180}Hg, of which the most significant are the 0{sub 2}{sup +} at 419.6 keV and the 2{sub 2}{sup +} at 601.3 keV. The former is the bandhead of an excited band in {sup 180}Hg assumed originally to be of prolate nature. From the {beta} feeding to the different states in {sup 180}Hg, the ground-state spin of {sup 180}Tl was deduced to be (4{sup -},5{sup -}).

Elseviers, J.; Bree, N.; Diriken, J.; Huyse, M.; Ivanov, O.; Van den Bergh, P.; Van Duppen, P. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, University of Leuven, BE-3001 Leuven (Belgium); Andreyev, A. N. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, University of Leuven, BE-3001 Leuven (Belgium); School of Engineering and Science, University of the West of Scotland, Paisley, PA1 2BE, UK and the Scottish Universities Physics Alliance (SUPA) (United Kingdom); Antalic, S. [Department of Nuclear Physics and Biophysics, Comenius University, SK-84248 Bratislava (Slovakia); Barzakh, A.; Fedorov, D. [Petersburg Nuclear Physics Institute, RU-188350 Gatchina (Russian Federation); Cocolios, T. E.; Seliverstov, M. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, University of Leuven, BE-3001 Leuven (Belgium); ISOLDE,CERN, CH-1211 Geneve 23 (Switzerland); Comas, V. F.; Heredia, J. A. [Gesellschaft fuer Schwerionenforschung, Planckstrasse 1, DE-64291 Darmstadt (Germany); Fedosseyev, V. N.; Marsh, B. A. [EN Department, CERN, CH-1211 Geneve 23 (Switzerland); Franchoo, S. [Institut de Physique Nucleaire, IN2P3-CNRS/Universite Paris-Sud, FR-91406 Orsay Cedex (France); Koester, U. [Institut Laue Langevin, 6 rue Jules Horowitz, FR-38042 Grenoble Cedex 9 (France); Page, R. D. [Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom)

2011-09-15T23:59:59.000Z

78

Combined SIMS, AES and XPS Study of CdxHg1-xTe  

Science Journals Connector (OSTI)

The ternary compound CdxHg1_xTe is of great importance in infrared technology. The band gap of this material depends critically on the concentration x. Therefore, a detailed knowledge of the surface and bulk comp...

O. Ganschow; H. M. Nitz; L. Wiedmann…

1979-01-01T23:59:59.000Z

79

Mercury (Hg) and methyl mercury (MMHg) bioaccumulation in three fish species (sea food) from Persian Gulf  

Science Journals Connector (OSTI)

In this study, mercury (Hg) and methyl mercury (MMHg) were determined in three fish species including benthic, benthopelagic and pelagic fish from Arvand river, northwest of Persian Gulf. Mercury and methyl mercu...

Sajad Abdolvand; Sahar Kayedinejad Esfahani…

2014-09-01T23:59:59.000Z

80

Relativistic doppler effect in199Hg+ stored ions atomic frequency standard  

Science Journals Connector (OSTI)

RF traps are widely used nowadays in high resolution hyperfine spectroscopy. The spectrum of the microwave hyperfine transition at 40.5 GHz of the fundamental level2 S 1/2 of199Hg+

C. Meis; M. Jardino; B. Gely; M. Desaintfuscien

1989-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

H.G. Rickover, 1964 | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

1960's H.G. Rickover, 1964 Print Text Size: A A A FeedbackShare Page Citation For engineering and demonstrative leadership in the development of safe and reliable nuclear...

82

RECIPIENT:Gwinnett Co, GA  

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

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

83

Novel GaAs Devices  

Science Journals Connector (OSTI)

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

Michael Shur

1987-01-01T23:59:59.000Z

84

Quantum Critical Transition Amplifies Magnetoelastic Coupling in Mn[N(CN)2]2  

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

We report the discovery of a magnetic quantum critical transition in Mn[N(CN)2]2 that drives the system from a canted antiferromagnetic state to the fully polarized state with amplified magnetoelastic coupling as an intrinsic part of the process. The local lattice distortions, revealed through systematic phonon frequency shifts, suggest a combined MnN6 octahedra distortion+counterrotation mechanism that reduces antiferromagnetic interactions and acts to accommodate the field-induced state. These findings deepen our understanding of magnetoelastic coupling near a magnetic quantum critical point and away from the static limit.

Brinzari, T. V.; Chen, P.; Sun, Q.-C.; Liu, J.; Tung, L.-C.; Wang, Y.; Schlueter, J. A.; Singleton, J.; Manson, J. L.; Whangbo, M.-H.; Litvinchuk, A. P.; Musfeldt, J. L.

2013-06-01T23:59:59.000Z

85

Sub-Doppler Stark Spectroscopy in the A?X (1,0) Band of CN  

SciTech Connect (OSTI)

The effect of external electric fields has been measured in hyperfine-resolved sub-Doppler transitions in the A {sup 2}{Pi}-X {sup 2}{Sigma} (1,0) band of the CN radical near 10900 cm{sup -1}. Static electric fields less than 1 kV/cm are sufficient to mix the most closely spaced {Lambda}-dpublets in the A state, leading to Stark spectra with both new and shifted resonances. Simulations of the saturation-dip Stark spectral line profiles allow extraction of the A-state permanent electric dipole moment with a magnitude of 0.06 {+-} 0.02 D.

Hall, G.E.; Hause, M.L.; Sears, T.J.

2009-11-26T23:59:59.000Z

86

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

87

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

88

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

89

Study of implantation in HgCdTe by electrolyte electroreflectance  

Science Journals Connector (OSTI)

Electrolyte electroreflectance (EER) and Hall?effect measurements have been performed on liquid phase epitaxy (LPE) layers of Hg1?x Cd x Te as grown with x=0.31 implanted with B ions implanted and annealed and annealed but not implanted. The use of our generalized theory to fit the EER results allowed us to study in detail as a function of depth the roles of implantation and annealing in Hg migration and in the formation of extended two?dimensional defects antisites and inhomogeneous strains. This is the first systematic EER study of the effects of implantation in state?of?the?art LPE materials. In the region affected by implantation our results suggest the diffusion of displaced Hg in the postimplant annealing process is associated with Te antisite formation and with compensating inhomogeneous strains. Moreover this Hg migration generates a region located approximately in the middle of the n?type layer which actually has a wider gap than the bulk. The relaxation of the lattice and the healing of damage promoted by the anneal are accompanied by a Hg redistribution which tends to lessen the disruptive effects of the antisite complexes. This picture of the implantation process is consistent with earlier conclusions.

P. M. Raccah; J. W. Garland; Z. Zhang; D. Yang; L. O. Bubulac; W. E. Tennant

1987-01-01T23:59:59.000Z

90

High Efficiency Large Area AlGaAs/GaAs Concentrator Solar Cells  

Science Journals Connector (OSTI)

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

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

1981-01-01T23:59:59.000Z

91

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

E-Print Network [OSTI]

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

Jalali. Bahram

92

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

E-Print Network [OSTI]

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

Saadat, Omair I

2010-01-01T23:59:59.000Z

93

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

94

Iodide retention by cinnabar (HgS) and chalcocite (Cu{sub 2}S)  

SciTech Connect (OSTI)

Sorption of iodide (I{sup {minus}}) on cinnabar (HgS) and chalcocite (Cu{sub 2}S) was examined as a function of pH at 25{degrees}C in a series of batch experiments. Calculated distribution ratios (K{sub d}) far exceed those reported for other minerals; maximal K{sub d}`s of 1375 cc/g (Cu{sub 2}S) and 3080 c/g (HgS) were observed between pH 4-5, but wre substantial at all pH`s measured (4 < pH < 10). Iodide sorption apparently occurs by the formation of an insoluble surface solid solution with exposed Hg and Cu sites. Surface solid solution formation is favored at low pH due to the lessened electrostatic repulsion of the iodide ion by the sulfide surfaces.

Anderson, H.L.; Balsley, S.D.; Brady, P.V.

1995-07-01T23:59:59.000Z

95

GaAs–based quantum cascade lasers  

Science Journals Connector (OSTI)

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

2001-01-01T23:59:59.000Z

96

The Chemical Separation of Eka-Hg from CERN W Targets in view of Recent Relativistic Calculations  

E-Print Network [OSTI]

In 1971 evidence for the production of element 112 via secondary reactions in CERN W targets was obtained. The evidence was mainly based on the observation of fission fragments in Hg sources separated from the W targets, on the measured masses of the fissioning nuclei and on the assumption that element 112 (Eka-Hg) actually behaves like Hg in the chemical separation process. This assumption is analyzed in view of recent relativistic calculations of the electronic structure of element 112. It is shown that in the superheavy element region only the chemistry of element 112 is similar to that of Hg.

D. Kolb; A. Marinov; G. W. A. Newton; R. Brandt

2004-12-07T23:59:59.000Z

97

Infrared Intensity Enhancement of the CN Stretch of HCN by Coadsorbed CO on the Cu(100) Surface  

Science Journals Connector (OSTI)

Reflection absorption infrared spectra reveal a strong enhancement in the intensity of the CN stretch in a mixed ordered overlayer of HCN and CO on the Cu(100) surface. Various combinations of HCN and CO isotopomers show that the intensity enhancement decreases with increasing frequency difference between ?CN and ?CO. The intensity of the 2092 cm-1 band of H12C14N is enhanced by a factor of 155±20 through coupling to the 2077 cm-1 band of 12C16O. A simple two-state coupling model explains the isotopomer dependence of the degree of enhancement.

Hugo Celio and Michael Trenary

2000-05-22T23:59:59.000Z

98

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

99

Observation de super-rseaux CdTe-HgTe par microscopie lectronique en transmission  

E-Print Network [OSTI]

-conducteurs II-VI a été beaucoup plus tardive [2]. Dans cette dernière famille, le système CdTe- HgTe présente l'avantage d'un accord de maille quasi parfait entre les deux composés (a = 0,648 nm pour CdTe contre a = 0 JET MOL�CULAIRE. - Les super- réseaux CdTe-HgTe ont été épitaxiés sur un substrat CdTe d

Paris-Sud XI, Université de

100

Concurrent Collections (CnC): A new approach to parallel programming  

ScienceCinema (OSTI)

A common approach in designing parallel languages is to provide some high level handles to manipulate the use of the parallel platform. This exposes some aspects of the target platform, for example, shared vs. distributed memory. It may expose some but not all types of parallelism, for example, data parallelism but not task parallelism. This approach must find a balance between the desire to provide a simple view for the domain expert and provide sufficient power for tuning. This is hard for any given architecture and harder if the language is to apply to a range of architectures. Either simplicity or power is lost. Instead of viewing the language design problem as one of providing the programmer with high level handles, we view the problem as one of designing an interface. On one side of this interface is the programmer (domain expert) who knows the application but needs no knowledge of any aspects of the platform. On the other side of the interface is the performance expert (programmer or program) who demands maximal flexibility for optimizing the mapping to a wide range of target platforms (parallel / serial, shared / distributed, homogeneous / heterogeneous, etc.) but needs no knowledge of the domain. Concurrent Collections (CnC) is based on this separation of concerns. The talk will present CnC and its benefits. About the speaker Kathleen Knobe has focused throughout her career on parallelism especially compiler technology, runtime system design and language design. She worked at Compass (aka Massachusetts Computer Associates) from 1980 to 1991 designing compilers for a wide range of parallel platforms for Thinking Machines, MasPar, Alliant, Numerix, and several government projects. In 1991 she decided to finish her education. After graduating from MIT in 1997, she joined Digital Equipment?s Cambridge Research Lab (CRL). She stayed through the DEC/Compaq/HP mergers and when CRL was acquired and absorbed by Intel. She currently works in the Software and Services Group / Technology Pathfinding and Innovation.

None

2011-10-06T23:59:59.000Z

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101

Coulomb excitation of 73Ga  

E-Print Network [OSTI]

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

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

2010-10-13T23:59:59.000Z

102

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

E-Print Network [OSTI]

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

Ebbers, André

2003-01-01T23:59:59.000Z

103

Role of Pyrazine-N,N?-dioxide in [W(CN)8]n?-Based Hybrid Networks: Anion?? Interactions  

Science Journals Connector (OSTI)

Role of Pyrazine-N,N?-dioxide in [W(CN)8]n?-Based Hybrid Networks: Anion?? Interactions ... The cyanide-bridged skeleton shows mixed square-octagonal grid type topology. ... Magnetic measurements were performed using the equipment purchased from the Large Research Infrastructure Fund of the Polish Ministry of Science and Higher Education (decision no. ...

Robert Podgajny; Dawid Pinkowicz; Bernard Czarnecki; Marcin Kozie?; Szymon Chor??y; Magdalena Wis; Wojciech Nitek; Micha? Rams; Barbara Sieklucka

2014-07-07T23:59:59.000Z

104

Electronic structure of the molecule-based magnet MnN,,CN...22 from theory and experiment  

E-Print Network [OSTI]

, Louisiana 70118 Received 27 November 2001; published 24 July 2002 The electronic structure of the Mn-based determined recently by Kurmoo and Kepert.2,3 More recently, x-ray structure of the Mn-based material has beenElectronic structure of the molecule-based magnet MnN,,CN...22 from theory and experiment M. R

Liu, Amy Y.

105

Appendix: Mercury Emissions used in CAM-Chem/Hg model. 1. Anthropogenic emissions  

E-Print Network [OSTI]

Appendix: Mercury Emissions used in CAM-Chem/Hg model. 1. Anthropogenic emissions The anthropogenic emission of mercury is directly adopted from global mercury emission inventory [Pacyna et al., 2005]. The anthropogenic emissions are shown in annual averaged total mercury emissions. (Unit: µg/m2 /day) 2. Land

Meskhidze, Nicholas

106

creasing Hg2 concentration. After correcting for the initial shift caused by the new environment,  

E-Print Network [OSTI]

- tical density 9 4). The HgCl2 was still detected through these highly absorptive media (Fig. 3D-SWNTs and inserted into whole blood and muscle tissue. The complex was added directly to a black dye solution (op). The near-IR fluorescence of DNA-SWNTs in the dye solution exhibited the same response as SWNTs in pure

Garzione, Carmala N.

107

Optical Diagnostics Hg_jet_meeting, 01-18-05 Thomas Tsang  

E-Print Network [OSTI]

Optical Diagnostics Hg_jet_meeting, 01-18-05 Thomas Tsang · tight environment · high radiation area · non-serviceable area · passive components · optics only, no active electronics · back illuminated with a single fiber laser - pulsed laser X · transmit image through flexible fiber bundle #12;Optical

McDonald, Kirk

108

SmartHG: Energy Demand Aware Open Services for Smart Grid Intelligent Automation  

E-Print Network [OSTI]

SmartHG: Energy Demand Aware Open Services for Smart Grid Intelligent Automation Enrico Tronci- ing, energy storage (e.g., batteries or plug-in hybrid electric vehicles) and energy production (e economically viable Intelligent Automation Services (IASs), which gather real-time data about energy usage from

Tronci, Enrico

109

H-G Diagram Based Rotor Parameters Identification for Induction Motors Thermal Monitoring  

E-Print Network [OSTI]

H-G Diagram Based Rotor Parameters Identification for Induction Motors Thermal Monitoring Mohamed: In this paper, an effective on-line method for induction motor parameter identification, especially rotor for each operating point. Computer simulations and experimental tests, carried out for a 4-kW four

Brest, Université de

110

Effect of Divalent Metals on Hg(II) Uptake and Methylation by Bacteria  

Science Journals Connector (OSTI)

The production of methylmercury by some bacteria is a key first step in the accumulation and biomagnification of this toxic substance in aquatic food webs, a major human health concern. By direct measurement of cellular Hg(II) uptake in model iron and ...

Jeffra K. Schaefer; Aleksandra Szczuka; François M. M. Morel

2014-02-10T23:59:59.000Z

111

Modelling Glass Parisons R.M.M. Mattheij, K. Wang & H.G. ter Morsche  

E-Print Network [OSTI]

Modelling Glass Parisons R.M.M. Mattheij, K. Wang & H.G. ter Morsche EMail: mattheij@win.tue.nl Abstract In order to design better glass products, numerical modelling is essential. In this paper we focus, more specifically, on pressing forms, so called parison, appearing in the produc­ tion of packing glass

Eindhoven, Technische Universiteit

112

Pinning lattice: Effect of rhenium doping on the microstructural evolution from Tl-2212 to Hg-1212 films during cation exchange  

E-Print Network [OSTI]

In a cation exchange process developed recently by some of us, epitaxial HgBa2CaCu2O6 films can be obtained by diffusing volatile Tl cations out of, and simultaneously diffusing Hg cations into, the crystalline lattice of ...

Wu, Judy; Zhao, H.

2004-08-15T23:59:59.000Z

113

Absorption of Narrow-Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail  

E-Print Network [OSTI]

Absorption of Narrow-Gap HgCdTe Near the Band Edge Including Nonparabolicity and the Urbach Tail, USA. 6.--e-mail: yonchang@uic.edu An analytical model describing the absorption behavior of Hg1-x. This model smoothly fits experimental absorption coefficients over energies ranging from the Urbach tail

Flatte, Michael E.

114

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

SciTech Connect (OSTI)

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

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

2012-04-01T23:59:59.000Z

115

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

Science Journals Connector (OSTI)

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

L. Bellaiche; Su-Huai Wei; Alex Zunger

1997-10-15T23:59:59.000Z

116

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

117

Theoretical study of radiative electron attachment to CN, C2H, and C4H radicals  

E-Print Network [OSTI]

A first-principle theoretical approach to study the process of radiative electron attachment is developed and applied to the negative molecular ions CN$^-$, C$_4$H$^-$, and C$_2$H$^-$. Among these anions, the first two have already been observed in the interstellar space. Cross sections and rate coefficients for formation of these ions by radiative electron attachment to the corresponding neutral radicals are calculated. For completeness of the theoretical approach, two pathways for the process have been considered: (i) A direct pathway, in which the electron in collision with the molecule spontaneously emits a photon and forms a negative ion in one of the lowest vibrational levels, and (ii) an indirect, or two-step pathway, in which the electron is initially captured through non-Born-Oppenheimer coupling into a vibrationally resonant excited state of the anion, which then stabilizes by radiative decay. We develop a general model to describe the second pathway and show that its contribution to the formation o...

Douguet, Nicolas; Raoult, Maurice; Dulieu, Olivier; Orel, Ann E; Kokoouline, Viatcheslav

2015-01-01T23:59:59.000Z

118

*Intel and the Intel logo are registered trademarks of Intel Corporation. Other brands and names are the property of their respective owners The Concurrent Collections (CnC) Parallel Programming  

E-Print Network [OSTI]

are the property of their respective owners The Concurrent Collections (CnC) Parallel Programming Model and names are the property of their respective owners 8 Influence 1: Streaming ·!CnC is like Streaming

Hazelwood, Kim

119

Princeton Plasma Physics Lab - General Atomics (GA)  

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

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

American Fusion News Category: 
ga">General Atomics (GA)
120

Axi-symmetrical flow reactor for [sup 196]Hg photochemical enrichment  

DOE Patents [OSTI]

The present invention is directed to an improved photochemical reactor useful for the isotopic enrichment of a predetermined isotope of mercury, especially, [sup 196]Hg. Specifically, two axi-symmetrical flow reactors were constructed according to the teachings of the present invention. These reactors improve the mixing of the reactants during the photochemical enrichment process, affording higher yields of the desired [sup 196]Hg product. Measurements of the variation of yield (Y) and enrichment factor (E) along the flow axis of these reactors indicates very substantial improvement in process uniformity compared to previously used photochemical reactor systems. In one preferred embodiment of the present invention, the photoreactor system was built such that the reactor chamber was removable from the system without disturbing the location of either the photochemical lamp or the filter employed therewith. 10 figures.

Grossman, M.W.

1991-04-30T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

Surface characterization and electronic structure of HgTe nanocrystalline thin films  

Science Journals Connector (OSTI)

Mercury telluride (HgTe) nanocrystalline thin films were synthesized using an electrochemical deposition technique. The surface morphology of the thin films were investigated by atomic force microscopy (AFM) as a function of the film thickness which shows that an increase in film thickness increases the surface roughness. The scaling exponents such as roughness exponent, ? and growth exponent, ? associated with the film growth, determined from surface and power spectral analysis using AFM are found to be 0.88±0.05 and 0.21±0.04 respectively. The shifting of the valence and core levels to higher binding energy as evidenced from x-ray photoelectron spectroscopy, suggest the change in electronic structure of the nano-HgTe films possibly due to the surface roughness.

S. Rath, D. Paramanik, S. N. Sarangi, S. Varma, and S. N. Sahu

2005-11-08T23:59:59.000Z

122

The structural and electronic properties of amorphous HgCdTe from first-principles calculations  

Science Journals Connector (OSTI)

Amorphous mercury cadmium telluride (a-MCT) model structures, with x being 0.125 and 0.25, are obtained from first-principles calculations. We generate initial structures by computation alchemy method. It is found that most atoms in the network of amorphous structures tend to be fourfold and form tetrahedral structures, implying that the chemical ordered continuous random network with some coordination defects is the ideal structure for a-MCT. The electronic structure is also concerned. The gap is found to be 0.30 and 0.26 eV for a-Hg0.875Cd0.125Te and a-Hg0.75Cd0.25Te model structures, independent of the composition. By comparing with the properties of crystalline MCT with the same composition, we observe a blue-shift of energy band gap. The localization of tail states and its atomic origin are also discussed.

Huxian Zhao; Xiaoshuang Chen; Jianping Lu; Haibo Shu; Wei Lu

2014-01-01T23:59:59.000Z

123

Automated product recovery in a Hg-196 photochemical isotope separation process  

DOE Patents [OSTI]

A method of removing deposited product from a photochemical reactor used in the enrichment of [sup 196]Hg has been developed and shown to be effective for rapid re-cycling of the reactor system. Unlike previous methods relatively low temperatures are used in a gas and vapor phase process of removal. Importantly, the recovery process is understood in a quantitative manner so that scaling design to larger capacity systems can be easily carried out. 2 figs.

Grossman, M.W.; Speer, R.

1992-07-21T23:59:59.000Z

124

THE POSSIBLE INTERSTELLAR ANION CH{sub 2}CN{sup -}: SPECTROSCOPIC CONSTANTS, VIBRATIONAL FREQUENCIES, AND OTHER CONSIDERATIONS  

SciTech Connect (OSTI)

The A {sup 1}B{sub 1} Leftwards-Open-Headed-Arrow X-tilde{sup 1}A' excitation into the dipole-bound state of the cyanomethyl anion (CH{sub 2}CN{sup -}) has been hypothesized as the carrier for one diffuse interstellar band. However, this particular molecular system has not been detected in the interstellar medium even though the related cyanomethyl radical and the isoelectronic ketenimine molecule have been found. In this study, we are employing the use of proven quartic force fields and second-order vibrational perturbation theory to compute accurate spectroscopic constants and fundamental vibrational frequencies for X-tilde{sup 1} A' CH{sub 2}CN{sup -} in order to assist in laboratory studies and astronomical observations.

Fortenberry, Ryan C.; Lee, Timothy J. [NASA Ames Research Center, Moffett Field, CA 94035-1000 (United States)] [NASA Ames Research Center, Moffett Field, CA 94035-1000 (United States); Crawford, T. Daniel, E-mail: Ryan.C.Fortenberry@nasa.gov, E-mail: Timothy.J.Lee@nasa.gov [Department of Chemistry, Virginia Tech, Blacksburg, VA 24061 (United States)

2013-01-10T23:59:59.000Z

125

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

126

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

2011-01-07T23:59:59.000Z

127

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

128

US SoAtl GA Site Consumption  

Gasoline and Diesel Fuel Update (EIA)

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

129

US SoAtl GA Site Consumption  

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

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

130

CdTe AND CdTe : Hg ALLOYS CRYSTAL GROWTH USING STOICHIOMETRIC AND OFF-STOICHIOMETRIC  

E-Print Network [OSTI]

123 CdTe AND CdTe : Hg ALLOYS CRYSTAL GROWTH USING STOICHIOMETRIC AND OFF-STOICHIOMETRIC ZONE.-Briand, 92190 Meudon/Bellevue, France Résumé. 2014 En vue de la croissance de cristaux de CdTe de haute cristaux semi-isolants Cd0, 9Hg0, 1Te. Abstract. 2014 Some aspects of the thermodynamic state of CdTe

Paris-Sud XI, Université de

131

Deposition of diamond like carbon (DLC) and C-N films using ion beam assisted deposition (IBAD) technique and evaluation of their properties  

Science Journals Connector (OSTI)

Diamond like carbon films and C-N films were prepared using ion beam assisted deposition technique (IBAD). Tribological properties were studied by subjecting DLC coated films to the accelerated wear tests. The...

J Prabhjyot Pal; S C Patil; S B Ogale; S M Kanetkar…

1994-11-01T23:59:59.000Z

132

Statistical analysis of operational reliability for electric pump units CN 60–180 of VVER-1000 reactors with root estimation methods  

Science Journals Connector (OSTI)

We consider the problem of processing statistical data obtained during the operation of pumping units CN 60–180 operating as standard equipment of the VVER-1000 reactors. Data for analysis was taken from the indu...

A. V. Antonov; V. A. Chepurko; N. G. Zyulyaeva…

2010-07-01T23:59:59.000Z

133

Electrolyte electroreflectance in the characterization of HgCdTe heterostructures  

Science Journals Connector (OSTI)

We have used the technique of electrolyte electroreflectance (EER) coupled with electrochemicaletching to profile through epitaxial layers and heterostructures of Hg1?x Cd x Te. The need for proper electrochemical control during EER measurements is discussed. The resolution achieved in both composition ?x=±0.002 and etch depth ±30 Å has made possible the observation of the variations in composition at the ambient/epilayer epilayer/substrate and high?x/low?x interfaces. Good correlations of the profiles observed have been obtained with secondary ion mass spectroscopy electron dispersive x?ray diffraction and Rutherford backscattering measurements. The variation of the broadening parameter ? at these interfaces is also discussed.

L. E. A. Berlouis; L. M. Peter; M. G. Astles; J. Gough; R. G. Humphreys; S. J. C. Irvine; V. Steward

1987-01-01T23:59:59.000Z

134

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

135

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

136

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

137

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

138

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

139

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

SciTech Connect (OSTI)

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

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

2013-03-04T23:59:59.000Z

140

GA Solar | Open Energy Information  

Open Energy Info (EERE)

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

Note: This page contains sample records for the topic "hg cn 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

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

Science Journals Connector (OSTI)

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

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

2011-01-01T23:59:59.000Z

142

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

Science Journals Connector (OSTI)

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

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

2015-01-01T23:59:59.000Z

143

NETL: Hg Control – The Effects on By-products: What Do We Know and Where  

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

Hg Control – The Effects on By-products: Hg Control – The Effects on By-products: What Do We Know and Where Do We Go? Table of Contents Foreword Disclaimer Papers and Presentations Introductions Field Demonstrations Laboratory Studies Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government or any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

144

Observation of a remarkable temperature effect in the hydrogen bonding structure and dynamics of the CN-(H2O) cluster  

SciTech Connect (OSTI)

The CN-(H2O) cluster represents a model diatomic monohydrate with multiple solvation sites. We report joint experimental and theoretical studies of its structure and dynamics using temperature-controlled photoelectron spectroscopy (PES) and ab-initio electronic structure calculations. The observed PES spectra of CN-(H2O) display a remarkable temperature effect, namely that the T=12 K spectrum shows an unexpectedly large blue shift of 0.25 eV in the electron binding energy relative to the Room Temperature (RT) spectrum. Extensive theoretical analysis of the potential energy function (PEF) of the cluster at the CCSD(T) level of theory reveal the existence of two nearly isoenergetic isomers corresponding to H2O forming a H-bond with either the C or the N atom, respectively. This results in four topologically distinct minima, i.e., CN-(HaOHb), CN-(HbOHa), NC-(HaOHb) and NC-(HbOHa). There are two main pathways connecting these minima: (i) CN- tumbling relative to water and (ii) water rocking relative to CN-. The relative magnitude of the barriers associated with these two motions reverses between low [pathway (i) is preferred] and high [pathway (ii) is preferred] temperatures. As a result, at T=12 K the cluster adopts a structure that is close to the minimum energy CN-(H2O) configuration, while at RT it can effectively access regions of the PEF close to the transition state for pathway (ii), explaining the surprisingly large spectral shift between the 12 K and RT PES spectra. This work was supported by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences, US Department of Energy. Battelle operates Pacific Northwest National Laboratory for the US Department of Energy.

Wang, Xue B.; Werhahn, Jasper C.; Wang, Lai S.; Kowalski, Karol; Laubereau, Alfred; Xantheas, Sotiris S.

2009-09-03T23:59:59.000Z

145

Report on International Collaboration Involving the FE Heater and HG-A Tests at Mont Terri  

SciTech Connect (OSTI)

Nuclear waste programs outside of the US have focused on different host rock types for geological disposal of high-level radioactive waste. Several countries, including France, Switzerland, Belgium, and Japan are exploring the possibility of waste disposal in shale and other clay-rich rock that fall within the general classification of argillaceous rock. This rock type is also of interest for the US program because the US has extensive sedimentary basins containing large deposits of argillaceous rock. LBNL, as part of the DOE-NE Used Fuel Disposition Campaign, is collaborating on some of the underground research laboratory (URL) activities at the Mont Terri URL near Saint-Ursanne, Switzerland. The Mont Terri project, which began in 1995, has developed a URL at a depth of about 300 m in a stiff clay formation called the Opalinus Clay. Our current collaboration efforts include two test modeling activities for the FE heater test and the HG-A leak-off test. This report documents results concerning our current modeling of these field tests. The overall objectives of these activities include an improved understanding of and advanced relevant modeling capabilities for EDZ evolution in clay repositories and the associated coupled processes, and to develop a technical basis for the maximum allowable temperature for a clay repository. The R&D activities documented in this report are part of the work package of natural system evaluation and tool development that directly supports the following Used Fuel Disposition Campaign (UFDC) objectives: ? Develop a fundamental understanding of disposal-system performance in a range of environments for potential wastes that could arise from future nuclear-fuel-cycle alternatives through theory, simulation, testing, and experimentation. ? Develop a computational modeling capability for the performance of storage and disposal options for a range of fuel-cycle alternatives, evolving from generic models to more robust models of performance assessment. For the purpose of validating modeling capabilities for thermal-hydro-mechanical (THM) processes, we developed a suite of simulation models for the planned full-scale FE Experiment to be conducted in the Mont Terri URL, including a full three-dimensional model that will be used for direct comparison to experimental data once available. We performed for the first time a THM analysis involving the Barcelona Basic Model (BBM) in a full three-dimensional field setting for modeling the geomechanical behavior of the buffer material and its interaction with the argillaceous host rock. We have simulated a well defined benchmark that will be used for codeto- code verification against modeling results from other international modeling teams. The analysis highlights the complex coupled geomechanical behavior in the buffer and its interaction with the surrounding rock and the importance of a well characterized buffer material in terms of THM properties. A new geomechanical fracture-damage model, TOUGH-RBSN, was applied to investigate damage behavior in the ongoing HG-A test at Mont Terri URL. Two model modifications have been implemented so that the Rigid-Body-Spring-Network (RBSN) model can be used for analysis of fracturing around the HG-A microtunnel. These modifications are (1) a methodology to compute fracture generation under compressive stress conditions and (2) a method to represent anisotropic elastic and strength properties. The method for computing fracture generation under compressive load produces results that roughly follow trends expected for homogeneous and layered systems. Anisotropic properties for the bulk rock were represented in the RBSN model using layered heterogeneity and gave bulk material responses in line with expectations. These model improvements were implemented for an initial model of fracture damage at the HG-A test. While the HG-A test model results show some similarities with the test observations, differences between the model results and observations remain.

Houseworth, Jim; Rutqvist, Jonny; Asahina, Daisuke; Chen, Fei; Vilarrasa, Victor; Liu, Hui-Hai; Birkholzer, Jens

2013-11-06T23:59:59.000Z

146

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

147

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

E-Print Network [OSTI]

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

Atwater, Harry

148

Memorandum, CH2M HG Idaho, LLC, Request for Variance to Title 10 Code of Federal Regulations part 851, "Worker Safety and Health"  

Broader source: Energy.gov [DOE]

CH2M HG Idaho, LLC, Request for Variance to Title 10 Code of Federal Regulations part 851, "Worker Safety and Health"

149

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

150

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

151

Microsoft Word - Updated netl Hg program white paper v.1 July2008.doc  

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

08 1 08 1 An Update on DOE/NETL's Mercury Control Technology Field Testing Program Thomas J. Feeley, III 1 and Andrew P. Jones 2 1 U.S. Department of Energy, National Energy Technology Laboratory 2 Science Applications International Corporation The U.S. Department of Energy's National Energy Technology Laboratory (NETL), under the Office of Fossil Energy's Innovations for Existing Plants (IEP) Program, manages the premier mercury (Hg) research and development (R&D) program for coal- fired power generation facilities in the world. Working collaboratively with the U.S. Environmental Protection Agency (EPA), the Electric Power Research Institute (EPRI), power plant operators, state and local agencies, and a host of research organizations

152

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

153

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

154

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

155

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

156

Comparison of the optoacoustic and Hg tracer methods for the study of energy-transfer processes in gas mixtures  

SciTech Connect (OSTI)

Rates of energy transfer from vibrationally excited SF/sub 6/ and pentafluorobenzene to argon in the gas phase have been studied by using the Hg tracer technique and time-resolved optoacoustics. These two techniques which rely on fundamentally different physical principles were found to give equivalent results. The implications for the study of energy-transfer processes in gas mixtures are discussed.

Wallington, T.J.; Braun, W.; Beck, K.M.; Gordon, R.J.

1988-06-30T23:59:59.000Z

157

Role of step roughening in the formation of Ce silicide H.G. Lee a,b  

E-Print Network [OSTI]

Role of step roughening in the formation of Ce silicide on Si(111) H.G. Lee a,b , D. Lee a , S. Kim, and then diffuse toward the step edges whilst forming a more stable Ce silicide. The step roughening at the step at the same temperature. Ã? 2005 Elsevier B.V. All rights reserved. Keywords: Step roughening; STM; XPS

Kim, Sehun

158

Synthesis, structure, and properties of the high-temperature superconductor HgBa2CuO4+?  

Science Journals Connector (OSTI)

We report here the attempted synthesis of (Hg1-xCuy)Ba2CuO4+? (0?x?0.2, 0?y?0.2, y?x) and the results of a detailed characterization of the structural and superconducting properties of the resulting samples. Rietveld refinement of powder x-ray-diffraction data collected on all 15 samples synthesized found no partial Cu occupancy of the Hg site. We therefore conclude that for these samples no solid solution exists and the superconducting phase is simply HgBa2CuO4+?. Only one interstitial oxygen position O(3) was found, located exactly at the center of the Hg plane. An analysis of the structural refinements has produced a number of correlations between the exact location of the Ba2+ cation within the unit cell and a number of important superconducting parameters; these include the occupancy of the O(3) site, the extent of oxidation of the CuO2 planes, and the magnetic penetration depth.

J. P. Hodges; I. Gameson; P. P. Edwards; A. P. Kharel; A. Porch

1997-05-01T23:59:59.000Z

159

Exploiting the Higher Specificity of Silver Amalgamation: Selective Detection of Mercury(II) by Forming Ag/Hg Amalgam  

E-Print Network [OSTI]

, 32611-7200, United States *S Supporting Information ABSTRACT: Heavy metal ion pollution poses severe and biological samples. Contamination of the environment with heavy metal ions has been an important concern selective for Hg2+ and does not respond to other metal ions with up to millimolar concentration levels

Tan, Weihong

160

Wavelengths and oscillator strengths of Xe II from the UVES spectra of four HgMn stars  

E-Print Network [OSTI]

In spite of large overabundances of Xe II observed in numerous mercury-manganese (HgMn) stars, Xe II oscillator strengths are only available for a very limited number of transitions. As a consequence, several unidentified lines in the spectra of HgMn stars could be due to Xe II. In addition, some predicted Xe II lines are redshifted by about 0.1 A from stellar unidentified lines, raising the question about the wavelength accuracy of the Xe II line data available in the literature. For these reasons we investigated the Xe II lines lying in the 3900-4521 A, 4769-7542 A, and 7660-8000 A spectral ranges of four well-studied HgMn stars. We compared the Xe II wavelengths listed in the NIST database with the position of the lines observed in the high-resolution UVES spectrum of the xenon-overabundant, slowly rotating HgMn stars HR 6000, and we modified them when needed. We derived astrophysical oscillator strengths for all the Xe II observed lines and compared them with the literature values, when available. In this...

Yüce, K; Hubrig, S

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn ga" from the National Library of EnergyBeta (NLEBeta).
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161

Nuclear shape coexistence: A study of the even-even Hg isotopes using the interacting boson model with configuration mixing  

E-Print Network [OSTI]

Background: The Po, Pb, Hg, and Pt region is known for the presence of coexisting structures that correspond to different particle-hole configurations in the Shell Model language or equivalently to nuclear shapes with different deformation. Purpose: We intend to study the configuration mixing phenomenon in the Hg isotopes and to understand how different observables are influenced by it. Method: We study in detail a long chain of mercury isotopes, $^{172-200}$Hg, using the interacting boson model with configuration mixing. The parameters of the Hamiltonians are fixed through a least square fit to the known energies and absolute B(E2) transition rates of states up to $3$ MeV. Results: We obtained the IBM-CM Hamiltonians and we calculate excitation energies, B(E2)'s, quadrupole shape invariants, wave functions, isotopic shifts, and mean field energy surfaces. Conclusions: We obtain a fairly good agreement with the experimental data for all the studied observables and we conclude that the Hamiltonian and the states we obtain constitute a good approximation to the Hg isotopes.

J. E. Garcia-Ramos; K. Heyde

2013-12-17T23:59:59.000Z

162

GA-AL-SC | Department of Energy  

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

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

163

Low Efficiency Droop Green Nano-Pyramid {10 -11} InGaN/GaN Multiple Quantum Well LED  

Science Journals Connector (OSTI)

We report a low efficiency droop 520 nm green nano-pyramid InGaN/GaN multiple quantum well (MQW) LED. MQWs were grown on the semipolar {10 1} nano-pyramid facets. The device physics...

Cheng, Yuh-Jen; Chang, Shih-Pang; Lin, Da-Wei; Kuo, Hao-chung; Xiong, Kang-lin

164

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

Science Journals Connector (OSTI)

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

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

2013-01-01T23:59:59.000Z

165

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

E-Print Network [OSTI]

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

Thamm, Andreas

2001-01-01T23:59:59.000Z

166

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

167

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

168

Removal of elemental mercury (Hg(0)) by nanosized V{sub 2}O{sub 5}/TiO{sub 2} catalysts  

SciTech Connect (OSTI)

Novel reactive nanosized V{sub 2}O{sub 5}/TiO{sub 2} catalysts (aerogel, xerogel, and impregnated catalysts) for the removal of Hg{sup 0} and their synthesis methods have been introduced in this research. Aerogel catalyst has the highest surface area among the catalysts synthesized in this research and contained reactive monovanadates on its surfaces resulting in higher reactivity for the Hg{sup 0} removal than impregnated and selective catalytic reduction catalysts. XPS analyses on the surfaces of nanosized catalysts after the removal of Hg{sup 0} suggest that adsorbed Hg{sup 0} oxidatively transformed to Hg{sup O} by surface vanadates (mono- and poly vanadates), consistent with the Mars-Maessen mechanism. Early column breakthrough has been observed at temperatures above 300{sup o}C due mainly to the desorption of Hg{sup 0} from the catalyst surfaces. The decrease in Hg{sup 0} concentration and increase in catalyst content in a column reactor have increased the removal of Hg{sup 0}, indicating that the removal is a heterogeneous surface-limited reaction. At 400{sup o}C, the catalysts under air flow have shown a higher Hg{sup 0} removal because gas-phase oxygen from the flow could provide an oxygen-rich environment for producing more oxidized vanadate species on their surfaces. No significant difference in the Hg{sup 0} removal between different gas types (nitrogen and air) has been observed at 100{sup o}C. 27 refs., 5 figs.

Lee, W.; Bae, G.N. [Korea Advanced Institute of Science and Technology, Daejeon (Republic of Korea)

2009-03-01T23:59:59.000Z

169

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

E-Print Network [OSTI]

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

Sun, Yue-Jun

2004-01-01T23:59:59.000Z

170

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

Science Journals Connector (OSTI)

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

T. Nakanishi; S. Nakamura

1991-01-01T23:59:59.000Z

171

Draft Genome sequence of Frankia sp. strains CN3 , an atypical, non-infective (Nod-) ineffective (Fix-) isolate from Coriaria nepalensis  

SciTech Connect (OSTI)

We report here the genome sequence of Frankia sp. strain CN3, which was isolated from Coriaria nepalensis. This genome sequence is the first from the fourth lineage of Frankia, that are unable to re-infect actinorhizal plants. At 10 Mb, it represents the largest Frankia genome sequenced to date.

Ghodhbane-Gtari, Faten [University of New Hampshire; Beauchemin, Nicholas [University of New Hampshire; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Davenport, Karen W. [Los Alamos National Laboratory (LANL); Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Furnholm, Teal [University of New Hampshire; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Gtari, Maher [University of New Hampshire; Han, Cliff [Los Alamos National Laboratory (LANL); Han, James [U.S. Department of Energy, Joint Genome Institute; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Nouioui, Imen [University of Tunis-El Manar, Tunisia; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Santos, Catarina [Instiuto Celular e Aplicada, Portugal; Sen, Arnab [University of North Bengal, Siliguri, India; Sur, Saubashya [University of North Bengal, Siliguri, India; Szeto, Ernest [U.S. Department of Energy, Joint Genome Institute; Tavares, Fernando [Instiuto Celular e Aplicada, Portugal; Hazuki, Teshima [Los Alamos National Laboratory (LANL); Thakur, Subarna [University of North Bengal, Siliguri, India; Wall, Luis [University of Quilmes, Argentina; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Tisa, Louis S. [University of New Hampshire

2013-01-01T23:59:59.000Z

172

Preprint version 2011 IEEE International Conference on Robotics and Automation, Shanghai, CN A Passivity-Based Decentralized Approach for the Bilateral  

E-Print Network [OSTI]

Preprint version 2011 IEEE International Conference on Robotics and Automation, Shanghai, CN, search and rescue and exploration of wide areas, the use of a group of simple robots rather than a single complex robot has proven to be very effective and the problem of coordinating a group of agents has

173

Long-Range Ferromagnetic Ordering in Two-Dimensional Coordination Polymers Co[N(CN)2]2(L) [L ) Pyrazine Dioxide (pzdo) and 2-Methyl  

E-Print Network [OSTI]

) Pyrazine Dioxide (pzdo) and 2-Methyl Pyrazine Dioxide (mpdo)] with Dual µ- and µ3-[N(CN)2] Bridges Hao by the addition of ancillary ligands of pyrazine dioxide (pzdo) and 2-methyl pyrazine dioxide (mpdo) into the Co]- , possesses three coordination nitrogen atoms and several possible coordination modes: terminal, bidentate 1

Gao, Song

174

[Ni(PPh2NBn2)2(CH3CN)]2+ as an Electrocatalyst for H2 Production: Dependence on Acid Strength and Isomer Distribution  

Science Journals Connector (OSTI)

[Ni(PPh2NBn2)2(CH3CN)]2+ (where PPh2NBn2 is 1,5-dibenzyl-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane), has been studied as an electrocatalyst for the production of hydrogen in acetonitrile. ... Proton-Coupled Electron Transfer in Molecular Electrocatalysis: Theoretical Methods and Design Principles ...

Aaron M. Appel; Douglas H. Pool; Molly O’Hagan; Wendy J. Shaw; Jenny Y. Yang; M. Rakowski DuBois; Daniel L. DuBois; R. Morris Bullock

2011-04-22T23:59:59.000Z

175

Crossed beam reaction of cyano radicals with hydrocarbon molecules. III. Chemical dynamics of vinylcyanide ,,C2H3CN;X 1  

E-Print Network [OSTI]

of the olefin to give a long-lived CH2CH2CN intermediate. This collision complex fragments through a tight exit have been performed since they occur commonly in nature and play a key part in a wide variety, pyroly- sis, gas discharges, and in situ chemical reactions. In our laboratory we have recently developed

Kaiser, Ralf I.

176

Transferring oxygen isotopes to 1,2,4-benzotriazine 1-oxides forming the corresponding 1,4-dioxides by using the HOF$CH3CN complex  

E-Print Network [OSTI]

Transferring oxygen isotopes to 1,2,4-benzotriazine 1-oxides forming the corresponding 1,4-dioxides Available online 14 August 2012 Keywords: Oxygen transfer 18 O isotope Tirapazamine HOF$CH3CN F2/N2 N is their ability to capitalize on the low oxygen (hypoxic) environment found in many solid tumors. The lead

Gates, Kent. S.

177

Auger recombination suppression and band alignment in GaAsBi/GaAs heterostructures  

SciTech Connect (OSTI)

Using a combination of experimental and theoretical techniques we present the dependence of the bandgap E{sub g} and the spin orbit splitting energy ?{sub so}, with Bi concentration in GaAsBi/GaAs samples. We find that the concentration at which ?{sub so},> E{sub g} occurs at 9%. Both spectroscopic as well as first device results indicate a type I alignment.

Hild, K.; Batool, Z.; Jin, S. R.; Hossain, N.; Marko, I. P.; Sweeney, S. J. [Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, GU2 7XH (United Kingdom); Hosea, T. JC. [1 Advanced Technology Institute and Department of Physics, University of Surrey, Guildford, GU2 7XH, UK and also, Ibnu Sina Institute, Universiti Teknologi Malaysia, Johor Bahru, 81310 (Malaysia); Lu, X. [Department of Electrical and Computer Engineering, University of Victoria, Victoria BC, V8W 3P6, Canada and now VarianSemiconductor Equipment Associates, Gloucester, MA 01930 (United States); Tiedje, T. [Department of Electrical and Computer Engineering, University of Victoria, Victoria BC, V8W 3P6 (Canada)

2013-12-04T23:59:59.000Z

178

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

179

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

180

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

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


181

Implantation of carbon in GaAs  

SciTech Connect (OSTI)

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

Moll, A.J.

1992-03-01T23:59:59.000Z

182

O?[]O? nuclear ?-decay of ?²Ga  

E-Print Network [OSTI]

The branching ratio for the ?-Decay of ?²Ga to the first excited O? state in ?²Zn has been measured. It is possible to use this branching ratio to test the theoretical method of calculating the [] component of the charge correction term [], which...

Hyman, Bruce Carl

2012-06-07T23:59:59.000Z

183

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

184

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

SciTech Connect (OSTI)

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

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

2013-09-27T23:59:59.000Z

185

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

SciTech Connect (OSTI)

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

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

2013-11-25T23:59:59.000Z

186

Electrolyte electroreflectance study of the effects of anodization and of chemomechanical polish on Hg1?x Cd x Te  

Science Journals Connector (OSTI)

We havw shown that electrolyte electroreflectance (EER) can be used as a sensitive probe to study the effects of processing agents on the near surface bulk. Our results indicate that Br2/methanol may be damaging Hg?annealed materials to a depth of about 600 Angstroms depleting them in Cd and leaving their surfaces covered with a Te?rich layer. While it is possible to remove the damaged layer anodization?dissolution steps our results show that such a procedure must be terminated when the undamaged material has been reached. If it is continued the difference between the rates at which the Cd and Hg diffuse through the oxide would again deplete the interface in Cd.

A. Lastras?Martinez; U. Lee; J. Zehnder; P. M. Raccah

1982-01-01T23:59:59.000Z

187

Mechanical Properties, sliding wear and solid particle erosion behaviors of plasma enhanced magnetron sputtering CrSiCN coating Systems  

Science Journals Connector (OSTI)

Abstract CrSiCN coating systems with different concentrations of Cr, Si, C, and N were investigated for their microstructure, mechanical properties (hardness H, elastic modulus E and indentation fracture toughness KIC) and tribological behaviors using SEM, nano-indentation, indentation, pin-on-disk wear test, and sand particle erosion test. The wear behaviors, such as specific wear rate and Archard wear coefficient, showed inverse relationships with H3/E2 ratio, confirming that the resistance to plastic deformation is the essential factor governing sliding wear behavior. High H3/E2 ratios also contributed to increased resistances to erosion at low impingement angles. However, at higher impingement angles (>60°), coatings with lower index of brittleness (B=2.656 µm?1/2), higher critical load (P?=6.670 N) for crack initiation and fracture surface energy (?f=0.123 Jm?2) offered a higher erosion resistance. The indentation fracture toughness (KIC), hardness (H) and elastic modulus (E) are limited to interpret erosion behaviors in a comprehensive approach, suggesting that erosion is a complex process where multiple mechanical properties contribute to erosion performance.

Feng Cai; Xiao Huang; Qi Yang

2014-01-01T23:59:59.000Z

188

Two-phase nc-TiN/a-(C,CN{sub x}) nanocomposite films: A HRTEM and MC simulation study  

SciTech Connect (OSTI)

The grain growth in two-phase nanocomposite Ti-C{sub x}-N{sub y} thin films grown by reactive close-field unbalanced magnetron sputtering in an Ar-N{sub 2} gas mixture with microstructures comprising of nanocrystalline (nc-) Ti(N,C) phase surrounded by amorphous (a-) (C,CN{sub x}) phase was investigated by a combination of high-resolution transmission electron microscopy (HRTEM) and Monte Carlo (MC) simulations. The HRTEM results revealed that amorphous-free solid solution Ti(C,N) thin films exhibited polycrystallites with different sizes, orientations and irregular shapes. The grain size varied in the range between several nanometers and several decade nanometers. Further increase of C content (up to {approx}19 at.% C) made the amorphous phase wet nanocrystallites, which strongly hindered the growth of nanocrystallites. As a result, more regular Ti(C,N) nanocrystallites with an average size of {approx}5 nm were found to be separated by {approx}0.5-nm amorphous phases. When C content was further increased (up to {approx}48 at.% in this study), thicker amorphous matrices were produced and followed by the formation of smaller sized grains with lognormal distribution. Our MC analysis indicated that with increasing amorphous volume fraction (i.e. increasing C content), the transformation from nc/nc grain boundary (GB)-curvature-driven growth to a/nc GB-curvature-driven growth is directly responsible for the observed grain growth from great inhomogeneity to homogeneity process.

Guo, J.; Lu, Y. H.; Hu, X. J.; Shen, Y. G. [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon (Hong Kong)

2013-06-18T23:59:59.000Z

189

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

E-Print Network [OSTI]

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

Peinke, Joachim

190

Electrochemical reductions of Hg(II), ruthenium-nitrosyl complex, chromate, and nitrate in a strong alkaline solution  

SciTech Connect (OSTI)

The electrochemistry of low-level nuclear wastes, the reductions of Hg(II), [RuNO(NO{sub 2}){sub 4}OH]{sup 2{minus}}, CrO{sub 4}{sup 2{minus}}, and NO{sub 3}{sup {minus}} in 1.33 M NaOH solution have been studied primarily at nickel electrodes for electrocatalytic advantages. Hg(II) was reduced to Hg metal [equilibrium potential of 0.099 V vs NHE (normal hydrogen electrode)]. The ruthenium-nitrosyl complex, [RuNO(NO{sub 2}){sub 4}OH]{sup 2{minus}}, was reduced to Ru metal (half-wave potential of {minus}0.38 V vs NHE). Chromate was reduced to chromic hydroxide (equilibrium potential of {minus}0.24 V vs NHE). Nitrate reduction has two different regions of Tafel behavior from which reduction mechanisms are proposed. The exchange current densities for the nitrate reduction at Ni, Pb, Fe, and graphite were measured and the competition of the nitrate reduction with the hydrogen evolution investigated.

Bockris, J.O`M.; Kim, J. [Texas A and M Univ., College Station, TX (United States)

1996-12-01T23:59:59.000Z

191

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

192

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

193

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

E-Print Network [OSTI]

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

194

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

Science Journals Connector (OSTI)

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

W. Jeitschko; H. Nowotny; F. Benesovsky

1963-01-01T23:59:59.000Z

195

Electrical characteristics of the CdTe-n-CdHgTe structure fabricated in a single molecular-beam epitaxy process  

SciTech Connect (OSTI)

An extraordinary shape of the capacitance-voltage characteristics of CdTe-CdHgTe structures has been detected; these characteristics include a specific 'hump' in the inversion region, the height of which increased severalfold under illumination. Additional measurements using an optical probe, measurements of current-voltage characteristics, and an analysis of the energy-band diagram of the structure showed the following. CdTe, in contrast to CdHgTe, is a p-type semiconductor with an acceptor concentration of 1 x 10{sup 16} cm{sup -3}; there is a hole inversion layer in CdHgTe at the boundary with CdTe, which causes the 'hump'; and the barrier height for holes at the CdTe-Cd{sub 0.43}Hg{sub 0.57}Te interface was determined as 0.13 eV.

Mashukov, Yu. P., E-mail: dr_mashukov@mail.ru; Mikhailov, N. N.; Vasilyev, V. V. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2010-09-15T23:59:59.000Z

196

H.G. Okuno and M. Ali (Eds.): IEA/AIE 2007, LNAI 4570, pp. 444453, 2007. Springer-Verlag Berlin Heidelberg 2007  

E-Print Network [OSTI]

H.G. Okuno and M. Ali (Eds.): IEA/AIE 2007, LNAI 4570, pp. 444­453, 2007. © Springer-Verlag Berlin estimated the individuality of fingerprints [1]. Hong, et al. reviewed performance evaluation for #12

Cho, Sung-Bae

197

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

SciTech Connect (OSTI)

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

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

2000-07-01T23:59:59.000Z

198

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

199

Optimisation of doping cladding layers in AlGaInP/GaInP laser heterostructures  

SciTech Connect (OSTI)

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

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

2004-01-31T23:59:59.000Z

200

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 I–V results show that some of the graphene wrinkles act as high-conductive channels and exhibiting ohmic behaviors compared with the flat regions with Schottky characteristics. We have studied the effects of the graphene wrinkles using density-functional-theory calculations. It is found that the standing and folded wrinkles with zigzag or armchair directions have a tendency to decrease or increase the local work function, respectively, pushing the local Fermi level towards n- or p-type GaN and thus improving the transport properties. These results can benefit recent topical researches and applications for graphene as electrode material integrated in various semiconductor devices.

Zhong, Haijian; Liu, Zhenghui; Shi, Lin; Xu, Gengzhao; Fan, Yingmin; Huang, Zengli [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Wang, Jianfeng; Ren, Guoqiang; Xu, Ke, E-mail: kxu2006@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China)

2014-05-26T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

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

202

Evaluation of Flood Runoff Reduction Effect of LID (Low Impact Development) based on the Decrease in CN: Case Studies from Gimcheon Pyeonghwa District, Korea  

Science Journals Connector (OSTI)

Abstract LID are spread on a small scale throughout target area, therefore, evaluation of their overall effect on flood reduction is not straightforward. As one solution dealing with this problem, Yoo et al. (2012) proposed a methodology for quantifying the flood runoff reduction effect of storage facilities by curve number (CN). Introduction of various infiltration or storage facilities causes the decrease in CN, which can be calculated using the runoff. The result derived was summarized in a graph showing the decrease in CN as an effect of the runoff reduction. That is, the runoff reduction effect of infiltration or storage facilities was able to be easily estimated using the derived graph. In this study, LID effects of Gimcheon Pyeonghwa district in Korea was quantified using this method. Additionally, the reduction amount of the runoff volume using the method suggested by Yoo et al. (2012) was compared with that estimated by using SWMM 5.0. As a result of this, the effect of LID facilities was shown similarly in both cases using the methodology used in this study and simulated using SWMM 5.0. This result verified that the methodology was valid even though it is straightforward and simple.

J. Sin; C. Jun; J.H. Zhu; C. Yoo

2014-01-01T23:59:59.000Z

203

Optoelectrical characteristics of green light-emitting diodes containing thick InGaN wells with digitally grown InN/GaN  

Science Journals Connector (OSTI)

Compared with conventionally grown thin InGaN wells, thick InGaN wells with digitally grown InN/GaN exhibit superior optical properties. The activation energy (48 meV) of thick InGaN...

Yu, Chun-Ta; Lai, Wei-Chih; Yen, Cheng-Hsiung; Hsu, Hsu-Cheng; Chang, Shoou-Jinn

2014-01-01T23:59:59.000Z

204

In: Proceedings of the 1995 International environmental conference; 1995 May 7-10; Atlanta, GA. Atlanta, GA: TAPPI PRESS: 445-448; 1995.  

E-Print Network [OSTI]

. Atlanta, GA: TAPPI PRESS: 445-448; 1995. ENVIRONMENTALLY SOUND ALTERNATIVES FOR UPGRADING MIXED OFFICE

Abubakr, Said

205

Surface Science Analysis of GaAs Photocathodes Following Sustained...  

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

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

206

P-type doping of GaN  

SciTech Connect (OSTI)

After implantation of As, As + Be, and As + Ga into GaN and annealing for short durations at temperatures as high as 1500 C, the GaN films remained highly resistive. It was apparent from c-RBS studies that although implantation damage did not create an amorphous layer in the GaN film, annealing at 1500 C did not provide enough energy to completely recover the radiation damage. Disorder recovered significantly after annealing at temperatures up to 1500 C, but not completely. From SIMS analysis, oxygen contamination in the AIN capping layer causes oxygen diffusion into the GaN film above 1400 C. The sapphire substrate (A1203) also decomposed and oxygen penetrated into the backside of the GaN layer above 1400 C. To prevent donor-like oxygen impurities from the capping layer and the substrate from contaminating the GaN film and compensating acceptors, post-implantation annealing should be done at temperatures below 1500 C. Oxygen in the cap could be reduced by growing the AIN cap on the GaN layer after the GaN growth run or by depositing the AIN layer in a ultra high vacuum (UHV) system post-growth to minimize residual oxygen and water contamination. With longer annealing times at 1400 C or at higher temperatures with a higher quality AIN, the implantation drainage may fully recover.

Wong, R.K.

2000-04-10T23:59:59.000Z

207

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

Science Journals Connector (OSTI)

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

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

2004-01-01T23:59:59.000Z

208

Spectral-kinetic properties of heterostructures with GaAsSb/InGaAs/GaAs-based quantum wells emitting in the range of 1.0-1.2 {mu}m  

SciTech Connect (OSTI)

The spectral-kinetic properties of heterostructures with GaAs/GaAsSb-based and GaAsSb/InGaAs/GaAs-based quantum wells, emitting in the range of 1.0-1.2 {mu}m are studied with picosecond and nanosecond temporal resolution. Intense photoluminescence in the GaAsSb/InGaAs/GaAs structure, as well as an increase in the photoluminescence wavelength by a factor of 2.5 and a shift of the location of the maximum of the peak ({approx}100 meV) to the longer-wavelength region were observed up to room temperature. It is established that as the molar fraction of Sb and the thickness of the InGaAs layer increase, the energy of the fundamental transition decreases by a factor of 140 meV compared with the GaAsSb/InGaAs/GaAs structure with a lower Sb content and a smaller thickness of the InGaAs layer. At 300 K, the emission wavelength of such a structure was 1.18 {mu}m. In addition, an increase in the thickness of the InGaAs layer led to an increase in the room-temperature photoluminescence intensity by a factor of 60, which is associated with a decrease in the energy of the fundamental state for electrons in the InGaAs layer and, consequently, to larger electron localization and smaller temperature quenching of photoluminescence.

Morozov, S. V., E-mail: more@ipm.sci.-nnov.ru; Kryzhkov, D. I.; Aleshkin, V. Ya. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)] [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Zvonkov, B. N.; Vikhrova, O. I. [Nizhni Novgorod State University, Physical-Technical Research Institute (Russian Federation)] [Nizhni Novgorod State University, Physical-Technical Research Institute (Russian Federation)

2013-11-15T23:59:59.000Z

209

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

Science Journals Connector (OSTI)

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

D. J. Chadi

1984-05-21T23:59:59.000Z

210

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

2013-12-04T23:59:59.000Z

211

Observation of photo darkening in self assembled InGaAs/GaAs quantum dots  

SciTech Connect (OSTI)

Photo darkening was observed in epitaxial InGaAs/GaAs quantum dots (QDs). The photoluminescence (PL) intensity of the QDs showed a non-reversible decrease under continuous laser irradiation. The time constants varied from tens of minutes to several hours, depending on the applied laser power. Based on the spectral evolution, it was concluded that the observed phenomenon should originate from laser induced structural damage and a sustained increase of non-radiative recombination rate in the wetting layer. Additionally, according to the PL decay dynamics at different laser powers, it is argued that there should exist other processes that hinder PL degradation at a high laser power.

Zhang Hongyi; Chen Yonghai; Zhou Xiaolong; Jia Yanan; Ye Xiaoling; Xu Bo; Wang Zhanguo [Key Laboratory of Semiconductor Materials Science and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

2013-05-07T23:59:59.000Z

212

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

213

SF6432-CN Construction  

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

or not) defense articles or furnishing defense services, Contractor represents that it is registered with the Directorate of Defense Trade Controls, as required by the ITAR, and it...

214

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

215

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

216

Abstract. --The density matrix formalism is applied to the interpretation of Mossbauer spectra of single crystals of K3Fe(CN) taken with polarized y-radiation to find the average electric hyper-  

E-Print Network [OSTI]

of single crystals of K3Fe(CN)« taken with polarized y-radiation to find the average electric hyper- fine also. By a properly chosen set of measurements sites. A MOSSBAUER STUDY OF THE ELECTRIC HYPERFINE

Boyer, Edmond

217

Nuclear structure ''southeast'' of {sup 208}Pb: Isomeric states in {sup 208}Hg and {sup 209}Tl  

SciTech Connect (OSTI)

The nuclear structure of neutron-rich N>126 nuclei has been investigated following their production via relativistic projectile fragmentation of a E/A=1 GeV {sup 238}U beam. Metastable states in the N=128 isotones {sup 208}Hg and {sup 209}Tl have been identified. Delayed {gamma}-ray transitions are interpreted as arising from the decay of I{sup {pi}}=(8{sup +}) and (17/2{sup +}) isomers, respectively. The data allow for the so far most comprehensive verification of the shell-model approach in the region determined by magic numbers Z<82 and N>126.

Al-Dahan, N. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Department of Physics, University of Kerbala, Kerbala (Iraq); Podolyak, Zs.; Regan, P. H.; Alkhomashi, N.; Deo, A. Y.; Farrelly, G.; Steer, S. J.; Cullen, I. J.; Gelletly, W.; Swan, T.; Thomas, J. S.; Walker, P. M. [Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Gorska, M.; Grawe, H.; Gerl, J.; Pietri, S. B.; Wollersheim, H. J.; Boutachkov, P.; Domingo-Pardo, C.; Farinon, F. [GSI, D-64291 Darmstadt (Germany)] (and others)

2009-12-15T23:59:59.000Z

218

Localized corrosion of GaAs surfaces and formation of porous GaAs  

SciTech Connect (OSTI)

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

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

1995-12-01T23:59:59.000Z

219

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

220

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.; Özgür, Ü.; Morkoç, H. [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Chabak, K. D.; Crespo, A.; Gillespie, J. K.; Fitch, R.; Kossler, M.; Walker, D. E.; Trejo, M.; Via, G. D.; Blevins, J. D. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)] [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)

2013-11-04T23:59:59.000Z

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221

The development of integrated chemical microsensors in GaAs  

SciTech Connect (OSTI)

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

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

1999-11-01T23:59:59.000Z

222

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

223

The Essentials for GA Water Planning The Relationship  

E-Print Network [OSTI]

Water Plan and the Alabama-Florida-Georgia Water Sharing Dispute (The failure to agree on the two Management F. Conservation & Reuse a. Programs for Water Use Efficiency b. Consumptive Use & Return Flows GThe Essentials for GA Water Planning The Relationship Between the Proposed GA State Comprehensive

Rosemond, Amy Daum

224

Structure of a Si(100)2×2-Ga surface  

Science Journals Connector (OSTI)

The 2×2 structure formed on a Ga-adsorbed Si(100) surface is determined using tensor low-energy electron diffraction. I-V curves of the parallel dimer model are in excellent agreement with those of the experiment, indicating that the actual surface has parallel dimer structure. Specific displacements of the topmost two surface layers (the protrusion of the Ga dimer toward the vacuum, the increase of the bond length of the Ga dimer, the stretching of the Si dimer, and the movement of the Si dimer toward the Ga dimer) with the elongation of the Si dimer back bond are observed in the optimized geometry. The Ga-Si bond angle measured from the Si(100) surface plane is recovered with these displacements from that of the ideal geometry where each bond length is assumed to be the sum of Pauling covalent radii. Subsurface layers are also deformed to keep the bond lengths near their bulk values.

H. Sakama; K. Murakami; K. Nishikata; A. Kawazu

1994-11-15T23:59:59.000Z

225

Electronic structure of metallic antiperovskite compound GaCMn3  

Science Journals Connector (OSTI)

We have investigated the electronic structures of antiperovskite GaCMn3 and related Mn compounds SnCMn3, ZnCMn3, and ZnNMn3. In the paramagnetic state of GaCMn3, the Fermi surface nesting feature along the ?R direction is observed, which induces the antiferromagnetic (AFM) spin ordering with the nesting vector Q??R. Calculated susceptibilities confirm the nesting scenario for GaCMn3, and also explain various magnetic structures of other antiperovskite compounds. Through the band folding effect, the AFM phase of GaCMn3 is stabilized. Nearly equal densities of states at the Fermi level in the ferromagnetic and AFM phases of GaCMn3 indicate that two phases are competing in the ground state.

J. H. Shim; S. K. Kwon; B. I. Min

2002-07-10T23:59:59.000Z

226

Improved photovoltaic performance of InGaN/GaN solar cells with optimized transparent current spreading layers  

Science Journals Connector (OSTI)

In0.135Ga0.865N/GaN p–i–n solar cells are fabricated and investigated with three types of transparent current spreading layers (TCSLs): Ni/Au layer type (Ni/Au-L), Ni/Au grid type (Ni/Au-G), and ITO layer type (I...

X. M. Cai; Y. Wang; Z. D. Li; X. Q. Lv; J. Y. Zhang; L. Y. Ying…

2013-05-01T23:59:59.000Z

227

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

228

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

Science Journals Connector (OSTI)

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

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

229

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

E-Print Network [OSTI]

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

Wetzel, Christian M.

230

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.

231

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

E-Print Network [OSTI]

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

Johnson, Derek Wade

2014-07-31T23:59:59.000Z

232

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

233

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

E-Print Network [OSTI]

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

Lu, Bin

234

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

E-Print Network [OSTI]

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

Lu, Wei

235

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

236

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

SciTech Connect (OSTI)

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

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

2002-10-01T23:59:59.000Z

237

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

238

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

Science Journals Connector (OSTI)

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

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

2005-01-14T23:59:59.000Z

239

Hall, Seebeck, and Nernst Coefficients of Underdoped HgBa2CuO4+?: Fermi-Surface Reconstruction in an Archetypal Cuprate Superconductor  

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

Charge-density-wave order has been observed in cuprate superconductors whose crystal structure breaks the square symmetry of the CuO2 planes, such as orthorhombic YBa2Cu3Oy (YBCO), but not so far in cuprates that preserve that symmetry, such as tetragonal HgBa2CuO4+? (Hg1201). We have measured the Hall (RH), Seebeck (S), and Nernst (?) coefficients of underdoped Hg1201 in magnetic fields large enough to suppress superconductivity. The high-field RH(T) and S(T) are found to drop with decreasing temperature and become negative, as also observed in YBCO at comparable doping. In YBCO, the negative RH and S are signatures of a small electron pocket caused by Fermi-surface reconstruction, attributed to charge-density-wave modulations observed in the same range of doping and temperature. We deduce that a similar Fermi-surface reconstruction takes place in Hg1201, evidence that density-wave order exists in this material. A striking similarity is also found in the normal-state Nernst coefficient ?(T), further supporting this interpretation. Given the model nature of Hg1201, Fermi-surface reconstruction appears to be common to all hole-doped cuprates, suggesting that density-wave order is a fundamental property of these materials.

Doiron-Leyraud, Nicolas; Lepault, S.; Cyr-Choinière, O.; Vignolle, B.; Grissonnanche, G.; Laliberté, F.; Chang, J.; Bariši?, N.; Chan, M. K.; Ji, L.; Zhao, X.; Li, Y.; Greven, M.; Proust, C.; Taillefer, Louis

2013-06-01T23:59:59.000Z

240

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

SciTech Connect (OSTI)

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

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

2013-11-14T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

Iron(III) Oxide Nanoparticles in the Thermally Induced Oxidative Decomposition of Prussian Blue, Fe4[Fe(CN)6]3  

Science Journals Connector (OSTI)

Iron(III) Oxide Nanoparticles in the Thermally Induced Oxidative Decomposition of Prussian Blue, Fe4[Fe(CN)6]3 ... Iron(III) oxides, particularly in the form of nanoparticles, are being used as catalysts, pigments, gas sensors, contrast agents in the magnetic resonance imaging, magnetic storage media, and furthermore, as basic components in the ferrofluid technologies or in biomagnetic separation processes. ... Structural and magnetic properties, methods of synthesis, and applications of seven Fe(III) oxide polymorphs, including rare beta, epsilon, amorphous, and high-pressure forms, are reviewed. ...

Radek Zboril; Libor Machala; Miroslav Mashlan; Virender Sharma

2004-10-05T23:59:59.000Z

242

Stereoselective SN2? alkylation reaction sequence of the ?,?-epoxy ?,?-unsaturated ester system via ?,?-chlorohydrin intermediates by the use of a R3Al–CuCN reagent  

Science Journals Connector (OSTI)

A novel stereoselective SN2? alkylation reaction sequence of the ?,?-epoxy ?,?-unsaturated ester system has been developed which involves a regioselective substitution reaction with chloride ions at the ?-position and a subsequent SN2? alkylation reaction of the resulting ?-chloro-?-hydroxy derivatives with a R3Al–CuCN reagent. The new methodology was demonstrated to be applicable to a variety of substrates and to provide various ?-hydroxy-?-alkyl-?,?-unsaturated esters including those bearing a quaternary asymmetric carbon atom at the ?-position in a highly stereoselective manner and high yields.

Fumihiko Yoshimura; Atsushi Matsui; Atsushi Hirai; Keiji Tanino; Masaaki Miyashita

2009-01-01T23:59:59.000Z

243

Three one-dimensional coordination polymers based on 1,1'-bis­(pyridin-4-ylmeth­yl)-2,2'-bi-1H-benzimidazole and HgX2 (X = Cl, Br and I)  

Science Journals Connector (OSTI)

The new ligand 1,1'-bis­(pyridin-4-ylmeth­yl)-2,2'-bi-1H-benzimidazole has been combined with HgX2 (X = Cl, Br and I) to create three one-dimensional coordination polymers. The three complexes have one-dimensional zigzag chains and the HgII centres are in a distorted tetra­hedral [HgX2N2] geometry in each case.

Li, A.-G.

2013-12-14T23:59:59.000Z

244

Novel signal inversion of laser beam induced current for femtosecond-laser-drilling-induced junction on vacancy-doped p-type HgCdTe  

SciTech Connect (OSTI)

In this paper, experimental results of temperature-dependent signal inversion of laser beam induced current (LBIC) for femtosecond-laser-drilling-induced junction on vacancy-doped p-type HgCdTe are reported. LBIC characterization shows that the traps induced by femtosecond laser drilling are sensitive to temperature. Theoretical models for trap-related p-n junction transformation are proposed and demonstrated using numerical simulations. The simulations are in good agreement with the experimental results. The effects of traps and mixed conduction are possibly the main reasons that result in the novel signal inversion of LBIC microscope at room temperature. The research results provide a theoretical guide for practical applications of large-scale array HgCdTe infrared photovoltaic detectors formed by femtosecond laser drilling, which may act as a potential new method for fabricating HgCdTe photodiodes.

Qiu, W. C.; Wang, R.; Xu, Z. J.; Jiang, T. [College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China); Cheng, X. A., E-mail: xiang-ai-cheng@126.com [College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China); State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha, Hunan 410073 (China); Science and Technology on Electro-Optical Information Security Control Laboratory, Hebei 065201 (China)

2014-05-28T23:59:59.000Z

245

Electrolyte electroreflectance study of laser annealing effects on the CdTe/Hg0.8Cd0.2Te (111) system  

Science Journals Connector (OSTI)

We have investigated the effects of laser annealing on the CdTe/Hg0.8Cd0.2Te?(111) system by measuring the electrolyte electroreflectance (EER) spectra from both the CdTe layer as well as the interface region. The sample was a Hg0.8Cd0.2Te?(111) single crystal with a 500?Å?thick polycrystallineCdTefilmdeposited on it; a section of the interface was annealed using the neodymium: yttrium aluminum garnet (Nd:YAG) laser 1.06??m line. Our observations indicate the presence of strain due to lattice mismatch at the interface; laser annealing relieves this strain. In addition the annealing also causes the diffusion of Hg ions from the interfacial region into the passivant layer. The changes in the line shapes of the EER spectra also show an improvement in the crystalline quality of the passivant layer.

P. M. Amirtharaj; Fred H. Pollak; J. R. Waterman; P. R. Boyd

1982-01-01T23:59:59.000Z

246

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

247

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

248

Exciton recombination dynamics in InxGa1-xAs/GaAs quantum wells  

Science Journals Connector (OSTI)

Low-temperature decay times ?PL are reported for a series of InxGa1-xAs/GaAs quantum wells. These show a nearly linear increase with increasing thickness (4?Lz?10 nm, x=0.15) but recombination in the widest well (12 nm) is dominated by nonradiative effects. The decay time increases almost linearly with temperature up to 50 K, as expected for free excitons. An increase in ?PL with increasing In composition (0.05?x?0.25, Lz=8 nm) is also observed. Wells with different In compositions exhibit a similar temperature behavior and there is a weak influence of strain on the decay time. Additional peaks in the photoluminescence spectra occur to the low-energy side of the free-exciton peaks. These features, which exhibit longer decay times, are attributed to excitons localized in In-rich islands arising from indium segregation.

Haiping Yu; Christine Roberts; Ray Murray

1995-07-15T23:59:59.000Z

249

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

250

Photovoltaic properties of GaAs:Be nanowire arrays  

SciTech Connect (OSTI)

Arrays of GaAs:Be nanowires are synthesized by molecular beam epitaxy on GaAs(111)B substrates. Prototypes of photovoltaic converters in which the grown nanowire arrays are used as active layers are produced by means of successive photolithography, etching, and metallization processes. Studying the photovoltaic properties of the fabricated structures using a solar radiation simulator demonstrates that the solarenergy conversion efficiency is about 0.1%. The value of the efficiency recalculated with the area occupied by the p-type nanowires on the surface of the n-type GaAs substrate taken into account amounts to 1.1%.

Bouravleuv, A. D.; Beznasyuk, D. V.; Gilstein, E. P. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Tchernycheva, M.; Luna Bugallo, A. De; Rigutti, L. [University Paris Sud 11, Institut d'Electronique Fondamentale UMR CNRS 8622 (France); Yu, L. [CNRS, Laboratoire de Physique des Interfaces et des Couches Minces (LPICM), Ecole Polytechnique (France); Proskuryakov, Yu. [University of Liverpool, Stephenson Institute for Renewable Energy (United Kingdom); Shtrom, I. V.; Timofeeva, M. A. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Samsonenko, Yu. B.; Khrebtov, A. I.; Cirlin, G. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-06-15T23:59:59.000Z

251

Photocurrent Spectroscopy of Single Wurtzite GaAs Nanowires  

SciTech Connect (OSTI)

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

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

2011-12-23T23:59:59.000Z

252

Effects of Ga ion-beam irradiation on monolayer graphene  

SciTech Connect (OSTI)

The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

Wang, Quan; Mao, Wei; Zhang, Yanmin; Shao, Ying; Ren, Naifei [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China)] [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Ge, Daohan [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China) [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

2013-08-12T23:59:59.000Z

253

Electroreflectance study of effects of indium segregation in molecular-beam-epitaxy-grown InGaAs/GaAs  

Science Journals Connector (OSTI)

Electrolyte electroreflectance (EER) experiments were performed on In 0.22 Ga 0.78 As/GaAs single quantum wells grown by the conventional molecular-beam-epitaxy (MBE) shutter operation and also by modified MBE shutter operation intended to form more compositionally abrupt normal and inverted interfaces. The latter included controlled thermal desorption of the surface segregated In at the InGaAs layer surface (flash off) and the deposition of In at the InGaAs/GaAs interface to eliminate compositional broadening (predeposition). The fundamental energy gap and subband transitions were determined experimentally and compared with an accurate calculation of the potential well problem including strain. These results confirmed the segregation of In atoms near the interface. The segregation was maximum in the conventional (normal) MBE sample and least with the modified growth incorporating predeposition and flash off as expected. The segregated atoms are observed to act as dopants and form junctions near the InGaAs/GaAs interface. This study shows that EER can be used as an effective tool for studying the segregation process in MBE growth.

K. Chattopadhyay; J. Aubel; S. Sundaram; J. E. Ehret; R. Kaspi; Keith R. Evans

1997-01-01T23:59:59.000Z

254

The effect of CdS QDs structure on the InGaP/GaAs/Ge triple junction solar cell efficiency  

Science Journals Connector (OSTI)

This work describes optical and electrical characteristics of InGaP/GaAs/Ge triple-junction (T-J) solar cells with CdS quantum dots (QDs) ... quantum dot effectively enhance the overall power conversion efficiency

Chen-Chen Chung; Binh Tinh Tran; Hau-Vei Han; Yen-Teng Ho…

2014-03-01T23:59:59.000Z

255

Improvement of orange ii photobleaching by moderate Ga3+ doping of titania and detrimental effect of structural disorder on Ga overloading  

Science Journals Connector (OSTI)

Highly photoactive Ga3+-doped anatase modification of titania was prepared by homogeneous hydrolysis of aqueous solutions mixture of titanium oxo-sulphate TiOSO4 and gallium(III) nitrate with urea. Incorporation of Ga3+ ...

Václav Štengl, Jilí Henych, Michaela Slušná, Tomáš Matys Grygar, Jana Velická, Martin Kormunda

2014-01-01T23:59:59.000Z

256

Kinetics of indirect photoluminescence in GaAs/AlxGa1?x As double quantum wells in a random potential with a large amplitude  

Science Journals Connector (OSTI)

The kinetics of indirect photoluminescence of GaAs/AlxGa1?x As double quantum wells, characterized by a random potential with a large amplitude (the linewidth of the indirect photoluminescence is ...

L. V. Butov; A. V. Mintsev; A. I. Filin…

1999-05-01T23:59:59.000Z

257

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

258

Structural and optical properties of GaAs-based heterostructures with Ge and Ge/InGaAs quantum wells  

SciTech Connect (OSTI)

GaAs-based heterostructures with Ge and Ge/InGaAs quantum wells are grown by laser-assisted sputtering. Structural and optical studies of the heterostructures are carried out. A broad photoluminescence line is observed in the wavelength range from 1300 to 1650 nm. The line corresponds to indirect transitions in the momentum space of the Ge quantum wells and to transitions between the In{sub 0.28}Ga{sub 0.72}As and Ge layers, indirect in coordinate space, but direct in momentum space.

Aleshkin, V. Ya.; Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru; Drozdov, M. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Zvonkov, B. N. [Nizhni Novgorod State University, Research Physical Technical Institute (Russian Federation); Kudryavtsev, K. E.; Tonkikh, A. A.; Yablonskiy, A. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Werner, P. [Max Planck Institute of Microstructure Physics (Germany)

2013-05-15T23:59:59.000Z

259

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

Science Journals Connector (OSTI)

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

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

2012-01-01T23:59:59.000Z

260

Polarization charges and polarization-induced barriers in AlxGa1xNGaN and InyGa1yNGaN heterostructures  

E-Print Network [OSTI]

N�GaN heterostructures L. Jia,a) E. T. Yu, D. Keogh, and P. M. Asbeck Department of Electrical and Computer EngineeringGa1 yN surrounded by n-GaN, capacitance­ voltage profiling studies combined with elementary will most likely require further improvements in p-type GaN conduc- tivity and fabrication of low-resistance

Yu, Edward T.

Note: This page contains sample records for the topic "hg cn 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

FUPWG Meeting Agenda - Atlanta, GA | Department of Energy  

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

Atlanta, GA Atlanta, GA FUPWG Meeting Agenda - Atlanta, GA October 7, 2013 - 3:16pm Addthis Energy on My Mind / FUPWG / Atlanta, GA / May 3-4, 2006 Hosted by: AGL Resources Logo May 3-4, 2006 Hosted by AGL Resources Atlanta, Georgia Tuesday, May 2, 2006 5:00 - 6:30 Steering Committee meeting in the Danube Tigris Room 6:30 until... Networking dinner at the Marriott Wednesday, May 3, 2006 7:45 am Registration/Continental Breakfast 8:30 - 8:45 Welcome from Suzanne Sitherwood, SVP, Southern Operations, President, Atlanta Gas Light, Chattanooga Gas & Florida City Gas 8:45 - 9:00 FEMP Southeast Regional Office Welcome Traci Leath, FEMP 9:00 - 9:45 Washington Update David McAndrew, FEMP 9:45 - 10:15 Break - Networking 10:15 - 11:20 Navy Technical Program Update Paul Kistler, U.S. Navy

262

Elba Island, GA Natural Gas Liquefied Natural Gas Imports from...  

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

Egypt (Million Cubic Feet) Elba Island, GA Natural Gas Liquefied Natural Gas Imports from Egypt (Million Cubic Feet) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2011 5,780...

263

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

264

GaAs solar cells close to the thermodynamic limit  

Science Journals Connector (OSTI)

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

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

265

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

266

Modeling of InGaN/Si tandem solar cells  

Science Journals Connector (OSTI)

We investigate theoretically the characteristics of monolithic InGaN/Si two-junction series-connected solar cells using the air mass 1.5 global irradiance spectrum. The addition of an InGaN junction is found to produce significant increases in the energy conversion efficiency of the solar cell over that of one-junction Si cells. Even when Si is not of high quality such two-junction cells could achieve efficiencies high enough to be practically feasible. We also show that further though smaller improvements of the efficiency can be achieved by adding another junction to form an InGaN/InGaN/Si three-junction cell.

L. Hsu; W. Walukiewicz

2008-01-01T23:59:59.000Z

267

Exciton front propagation in photoexcited GaAs quantum wells  

E-Print Network [OSTI]

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

Yang, Sen

268

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

269

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

SciTech Connect (OSTI)

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

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

2013-12-02T23:59:59.000Z

270

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

Science Journals Connector (OSTI)

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

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

2011-10-01T23:59:59.000Z

271

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

272

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

273

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

274

This chapter is divided into three sections. Section 7.1, `Trends', highlights possible links between factors which may govern the emergence of the HgMn phenomenon  

E-Print Network [OSTI]

Mn stars are represented by filled circles while normal stars are open squares. The solar abundance for HgMn stars are real. When synthesis was performed at solar abundance on the spectra of normal stars temperature. the solar value (Anders and Grevesse 1989) and HR7361 2.5oe m below the solar abundance, weight

Dworetsky, Mike

275

SNS Target Test Facility: Prototype Hg Operations and Remote Handling Tests P. T. Spampinato, T. W. Burgess, J. B. Chesser, V. B. Graves, and S.L. Schrock  

E-Print Network [OSTI]

SNS Target Test Facility: Prototype Hg Operations and Remote Handling Tests P. T. Spampinato, T. W remote handling techniques and tools for replacing target system components. During the past year and analytical data. These included a welded-tube heat exchanger, an electromagnetic flow meter, a hydraulically

McDonald, Kirk

276

Electronic properties of the Ga vacancy in GaP(110) surfaces determined by scanning tunneling microscopy  

Science Journals Connector (OSTI)

The electronic properties of uncharged Ga monovacancies in GaP(110) surfaces are determined from voltage-dependent scanning tunneling microscopy images. The signatures of localized defect states in the band gap are analyzed and their spatial location is determined. Empty and occupied defect states exist. Depressed dangling bonds in the occupied-state images indicate an inward relaxation of the neighboring P atoms. The results agree with recent theoretical work.

Ph. Ebert and K. Urban

1998-07-15T23:59:59.000Z

277

Capturing inhomogeneous broadening of the -CN stretch vibration in a Langmuir monolayer with high-resolution spectra and ultrafast vibrational dynamics in sum-frequency generation vibrational spectroscopy (SFG-VS)  

SciTech Connect (OSTI)

Even though in principle the frequency-domain and time-domain spectroscopic measurement should generate identical information for a given molecular system, inhomogeneous character of surface vibrations in the sum-frequency generation vibrational spectroscopy (SFG-VS) studies has only been studied with the time-domain SFGVS by mapping the decay of the vibrational polarization using ultrafast lasers, due to the lack of SFG vibrational spectra with high enough spectral resolution and accurate enough line shape. Here with recently developed high-resolution broadband SFG-VS (HR-BB-SFG-VS) we show that the inhomogeneous line shape can be obtained in the frequency-domain, for the anchoring CN stretch of the 4-n-octyl-4'-cyanobiphenyl (8CB) Langmuir monolayer at the air-water interface, and that an excellent agreement with the time-domain SFG free-induction-decay (FID) results can be established. We found that the 8CB CN stretch spectrum consists of a single peak centered at 2234.00 + * 0.01 cm-1 with a total line width of 10.9 + - 0.3 cm-1 at half maximum. The Lorentzian contribution accounts only for 4:7 + -0:4 cm-1 to this width and the Gaussian (inhomogeneous) broadening for as much as 8:1+*0:2 cm-1. Polarization analysis of the -CN spectra showed that the -CN group is tilted 57 + - 2 degrees from the surface normal. The large heterogeneity in the -CN spectrum is tentatively attributed to the -CN group interactions with the interfacial water molecules penetrated/accomodated into the 8CB monolayer, a unique phenomenon for the nCB Langmuir monolayers reported previously.

Velarde Ruiz Esparza, Luis A.; Wang, Hongfei

2013-08-28T23:59:59.000Z

278

Microstructural evolutions in converting epitaxial Tl2Ba2CaCu2Ox thin films to epitaxial HgBa2CaCu2O6+delta thin films  

E-Print Network [OSTI]

Superconducting HgBa2CaCu2O6+delta (Hg-1212) thin films were obtained from Tl2Ba2CaCu2Ox (Tl-2212) precursor films using a cation-exchange process. In this process, Tl cations on the precursor lattice were thermally excited ...

Wu, Judy; Siegal, M. P.; Xie, Y. Y.; Aytug, T.; Fang, L.

2003-02-01T23:59:59.000Z

279

High pressure conversion of \\{NOx\\} and Hg and their capture as aqueous condensates in a laboratory piston-compressor simulating oxy-fuel CO2 compression  

Science Journals Connector (OSTI)

Abstract Oxy-fuel technology for CO2 capture has largely focused on combustion characteristics as a driver towards demonstration. Impurity removal studies typically centre on the how current environmental control units (FGD, SCR, activated carbon beds) operate in oxy-fuel firing. However, it is expected that some removal of \\{NOx\\} and \\{SOx\\} may occur during compression of flue gas through the lead chamber process. Some commercial systems link the capture of mercury to the formation of acid condensates (as a soluble mercury salt). Mercury in compressed flue gas represents a potential corrosion risk in the processing of CO2 from oxy-fuel combustion processes. Gas phase elemental mercury (Hg0) is difficult to remove from the flue gas and the level of cleaning required to prevent corrosion of cryogenic brazed aluminium heat exchangers is uncertain. This work has investigated the behaviour of gaseous Hg0 in pressurised oxy-fuel systems in terms of the potential capture in acidic condensates, interaction with \\{NOx\\} gases and liquid stability on de-pressurisation. The work was undertaken on an adapted laboratory scale three stage axial-piston compressor with gas and liquid sampling at pressures up to 30 bar. The main finding was that gaseous Hg0 reacts readily with NO2 formed from NO oxidation at high pressure. This reaction occurred without the presence of water, either water vapour or liquid water, contrary to speculation in the literature. Without NO2, no capture of Hg0 was observed in the compression system. Overall, the capture of mercury during compression occurred as a consequence of high pressure, longer residence time and concentration of NO2. Capture rates of 100% Hg and 75–83% \\{NOx\\} were measured from the compressor exit at 30 bar g.

Rohan Stanger; Timothy Ting; Terry Wall

2014-01-01T23:59:59.000Z

280

Microscopic identification of the compensation mechanisms in Si-doped GaAs  

Science Journals Connector (OSTI)

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

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

1996-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn ga" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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281

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

282

Superconductivity and fluctuating magnetism in quasi-two-dimensional {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br probed with implanted muons.  

SciTech Connect (OSTI)

A muon-spin relaxation ({mu}{sup +}SR) investigation is presented for the molecular superconductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br. Evidence is found for low-temperature phase separation throughout the bulk of the material, with only a fraction of the sample showing a superconducting signal, even for slow cooling. Rapid cooling reduces the superconducting fraction still further. For the superconducting phase, the in-plane penetration depth is measured to be {lambda}{parallel} = 0.47(1) {micro}m, and evidence is seen for a vortex decoupling transition in applied fields above 40 mT. The magnetic fluctuations in the normal state produce a precipitous drop in relaxation rate above 100 K, and we discuss the possible causes for the unusual relaxation that we observe for T > T{sub c}.

Lancaster, T.; Blundel, S. J.; Pratt, F. L.; Schlueter, J. A.; Materials Science Division; Rutherford Appleton Lab.; Oxford Univ.

2011-01-19T23:59:59.000Z

283

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

SciTech Connect (OSTI)

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

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

2013-12-04T23:59:59.000Z

284

Lasing characteristics of GaSb/GaAs self-assembled quantum dots embedded in an InGaAs quantum well  

E-Print Network [OSTI]

Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico, New Mexico 87545 Received 26 February 2007; accepted 1 June 2007; published online 28 June 2007 intriguing optoelectronic device possibilities on GaAs substrates including lasers, detectors, or solar cells

Jalali. Bahram

285

Growth of Core?Shell Ga?GaN Nanostructures via a Conventional Reflux Method and the Formation of Hollow GaN Spheres  

Science Journals Connector (OSTI)

Gallium nitride (GaN) is an important III?V semiconductor with a wide direct band gap of ?3.4 eV. ... LiHMDS exhibits good solubility in TOA. ... The products were collected by centrifugation twice at 7000 rpm for 2 min in hexane, isopropanol, ethanol, and then deionized water. ...

Tz-Jun Kuo; Chi-Liang Kuo; Chun-Hong Kuo; Michael H. Huang

2009-02-05T23:59:59.000Z

286

Anisotropic Effect of Cd and Hg Doping on the Pauli Limited Superconductor CeCoIn5  

Science Journals Connector (OSTI)

We studied the effect of impurity on the first order superconducting (SC) transition and the high field-low temperature (HFLT) SC state of CeCoIn5 by measuring the specific heat of CeCo(In1-xCdx)5 with x=0.0011, 0.0022, and 0.0033 and CeCo(In1-xHgx)5 with x=0.000?16, 0.000?32, and 0.000?48 at temperatures down to 0.1 K and fields up to 14 T. Cd substitution rapidly suppresses the crossover temperature T0, where the SC transition changes from second to first order, to T=0??K with x=0.0022 for H?[100], while it remains roughly constant up to x=0.0033 for H?[001]. The associated anomaly of the proposed FFLO state in Hg-doped samples is washed out by x=0.000?48, while remaining at the same temperature, indicating high sensitivity of that state to impurities. We interpret these results as supporting the nonmagnetic, possibly FFLO, origin of the HFLT state in CeCoIn5.

Y. Tokiwa; R. Movshovich; F. Ronning; E. D. Bauer; P. Papin; A. D. Bianchi; J. F. Rauscher; S. M. Kauzlarich; Z. Fisk

2008-07-16T23:59:59.000Z

287

Conductivity of Hg{sub 3}In{sub 2}Te{sub 6} crystals in high electric fields  

SciTech Connect (OSTI)

The effect of electric field and temperature on the conductivity of bulk Hg{sub 3}In{sub 2}Te{sub 6} crystals is investigated. It is shown that the I-V characteristics in high electric fields are of the S type with the effect of switching into a low-resistance state. The critical voltage of transition from the Ohm law to the exponential dependence of the current (I) on the voltage (U) and the threshold voltage of transition into the region of negative differential resistance dU/dI = s< 0 linearly depend on the sample thickness. The activation energies of conductivity in low and high electric fields are determined. It is established that the superlinear portion of the I-V characteristic with dU/dI > 0 is described by the dependence of the type I = I{sub 0} exp(U/U{sub 0}) and caused by the electron transitions from the local centers with the energy level E{sub t} = 0.19 eV.

Grushka, O. G., E-mail: semicon-dpt@chnu.edu.ua; Chupyra, S. M.; Myslyuk, O. M.; Bilichuk, S. V.; Zabolotsky, I. I. [Fedkovich Chernovtsy National University (Ukraine)

2011-01-15T23:59:59.000Z

288

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

289

Metal contacts on ZnSe and GaN  

SciTech Connect (OSTI)

Recently, considerable interest has been focused on the development of blue light emitting materials and devices. The focus has been on GaN and ZnSe, direct band gap semiconductors with bands gaps of 3.4 and 2.6 eV, respectively. To have efficient, reliable devices it is necessary to have thermally and electrically stable Ohmic contacts. This requires knowledge of the metal-semiconductor reaction behavior. To date few studies have investigated this behavior. Much information has accumulated over the years on the behavior of metals on Si and GaAs. This thesis provides new knowledge for the more ionic wide band gap semiconductors. The initial reaction temperatures, first phases formed, and phase stability of Pt, Pd, and Ni on both semiconductors were investigated. The reactions of these metals on ZnSe and GaN are discussed in detail and correlated with predicted behavior. In addition, comparisons are made between these highly ionic semiconductors and Si and GaAs. The trends observed here should also be applicable to other II-VI and III-Nitride semiconductor systems, while the information on phase formation and stability should be useful in the development of contacts for ZnSe and GaN devices.

Duxstad, K.J. [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering; [Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1997-05-01T23:59:59.000Z

290

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

291

Site-controlled fabrication of Ga nanodroplets by focused ion beam  

SciTech Connect (OSTI)

Ga droplets are created by focused ion beam irradiation of GaAs surface. We report that ordered Ga droplets can be formed on the GaAs surface without any implantation damage. The droplets are characterized with bigger sizes than those droplets formed on damaged area. These aligned Ga droplets are formed via the migration of Ga atoms from ion irradiation area to the edge of undamaged GaAs surface and further nucleation into droplets. The morphological evolution and size distribution of these nanodroplets are investigated systematically with different beam irradiation time and incident angles. Based on this method, well positioned Ga nanodroplets, such as chains, are achieved by using focus ion beam patterning. The controllable assembly of droplets on undamaged semiconductor surface can be used to fabricate templates, to fabricate quantum structures and quantum devices by droplet epitaxy technique.

Xu, Xingliang; Wang, Zhiming M., E-mail: zhmwang@gmail.com [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China); Wu, Jiang; Li, Handong; Zhou, Zhihua [State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Wang, Xiaodong [Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China)

2014-03-31T23:59:59.000Z

292

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

E-Print Network [OSTI]

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

293

Atomic-Level Study of Melting Behavior of GaN Nanotubes. | EMSL  

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

Melting Behavior of GaN Nanotubes. Atomic-Level Study of Melting Behavior of GaN Nanotubes. Abstract: Molecular dynamics simulations with a Stillinger-Weber potential have been...

294

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

295

Device-level thermal analysis of GaN-based electronics  

E-Print Network [OSTI]

Gallium nitride (GaN)-based microelectronics are one of the most exciting semiconductor technologies for high power density and high frequency electronics. The excellent electrical properties of GaN and its related alloys ...

Bagnall, Kevin Robert

2013-01-01T23:59:59.000Z

296

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

Science Journals Connector (OSTI)

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

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

1997-02-15T23:59:59.000Z

297

http://www.staradvertiser.com/newspremium/20130824_Small_school_stands_tall_as_science_powerhouse_.html?id=220927791&c=n Page 1 of 3 Aug 28, 2013 07:39:07PM MDT  

E-Print Network [OSTI]

http://www.staradvertiser.com/newspremium/20130824_Small_school_stands_tall_as_science_powerhouse_.html?id=220927791&c=n Page 1 of 3 Aug 28, 2013 07:39:07PM MDT Small school stands tall as science powerhouse POSTED fifth -- well ahead of engineering powerhouses including the iconic Massachusetts Institute

298

THERMAL STUDY OF A GaN-BASED HEMT A Dissertation  

E-Print Network [OSTI]

of gallium-nitride (GaN) high-electron-mobility transistors (HEMTs) under bias conditions. An experimental

Sen, Mihir

299

Substrate-dependent wetting layer formation during GaN growth: Impact on the morphology of the films  

SciTech Connect (OSTI)

We have compared epitaxial growth of GaN films on 6H-SiC(0001)-({radical}(3)x{radical}(3))R30 deg. -Ga and on (0001)-sapphire. Predeposited Ga layers were nitrided by ion beam assisted molecular beam epitaxy. Whereas on SiC the initially deposited Ga covers the substrate surface completely, on sapphire only Ga droplets are present. The different distribution of the predeposited Ga affects the morphology of GaN significantly. Scanning electron microscopy and atomic force microscopy analysis of the grown films show that the complete wetting of the SiC substrate with Ga enhances finally the size and the flatness of GaN terraces and thus the quality of the film. X-ray photoelectron spectroscopy measurements reveal that metallic Ga resides also on top of the GaN films during the growth.

Sidorenko, A.; Peisert, H.; Neumann, H.; Chasse, T. [Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany); Leibniz-Institut fuer Oberflaechenmodifizierung e.V. Permoserstrasse 15, D-04318 Leipzig (Germany); Universitaet Tuebingen, Institut fuer Physikalische und Theoretische Chemie, Auf der Morgenstelle 8, D-72076 Tuebingen (Germany)

2007-08-15T23:59:59.000Z

300

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

SciTech Connect (OSTI)

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

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

1995-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

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

302

Spin dependent transport properties of Mn-Ga/MgO/Mn-Ga magnetic tunnel junctions with metal(Mg, Co, Cr) insertion layer  

SciTech Connect (OSTI)

We report a first principles theoretical investigation of spin polarized quantum transport in Mn{sub 2}Ga/MgO/Mn{sub 2}Ga and Mn{sub 3}Ga/MgO/Mn{sub 3}Ga magnetic tunneling junctions (MTJs) with the consideration of metal(Mg, Co, Cr) insertion layer effect. By changing the concentration of Mn, our calculation shows a considerable disparity in transport properties: A tunneling magnetoresistance (TMR) ratio of 852% was obtained for Mn{sub 2}Ga-based MTJs, however, only a 5% TMR ratio for Mn{sub 3}Ga-based MTJs. In addition, the influence of insertion layer has been considered in our calculation. We found the Co insertion layer can increase the TMR of Mn{sub 2}Ga-based MTJ to 904%; however, the Cr insertion layer can decrease the TMR by 668%; A negative TMR ratio can be obtained with Mg insertion layer. Our work gives a comprehensive understanding of the influence of different insertion layer in Mn-Ga based MTJs. It is proved that, due to the transmission can be modulated by the interfacial electronic structure of insertion, the magnetoresistance ratio of Mn{sub 2}Ga/MgO/Mn{sub 2}Ga MTJ can be improved by inserting Co layer.

Liang, S. H.; Tao, L. L.; Liu, D. P., E-mail: dpliu@iphy.ac.cn; Han, X. F., E-mail: xfhan@iphy.ac.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Lu, Y. [Institut Jean Lamour, UMR 7198, CNRS-Nancy Université, BP 239, 54506 Vandoeuvre (France)

2014-04-07T23:59:59.000Z

303

Novel photoaffinity ligands for the GA-receptor  

SciTech Connect (OSTI)

Previous studies from this laboratory have shown that certain N-substituted phthalimides (NSPs) exhibit GA-like activity in a range of specific bioassays and that bioactive NSPs compete with ({sup 3}H)-GA{sub 4} for soluble binding sites in cucumber homogenates. As such, these compounds may prove useful in the purification and characterization of GA receptor proteins. To this end, five azido-NSPs have been synthesized and are currently being screened for biological activity and photochemical stability. Three azido-NSPs elicit {alpha}-amylase production in barley half-seeds and stimulate tissue elongation in d{sub 5} maize, lettuce, sunflower, and soybean. Further evaluations are in progress and these data as well as the utility of these compounds as photo-affinity ligands will be discussed.

Suttle, J.C.; Hultstrand, J.F.; Tanaka, F.S. (USDA/ARS Biosciences Research Laboratory, Fargo, ND (USA))

1990-05-01T23:59:59.000Z

304

The polygallides: Yb{sub 3}Ga{sub 7}Ge{sub 3} and YbGa{sub 4}Ge{sub2}.  

SciTech Connect (OSTI)

Yb{sub 3}Ga{sub 7}Ge{sub 3} and YbGa{sub 4}Ge{sub 2} were obtained from reactions of Yb and Ge in excess liquid gallium. The crystal structure of Yb{sub 3}Ga{sub 7}Ge{sub 3} was refined using X-ray and neutron diffraction data on selected single crystals. Yb{sub 3}Ga{sub 7}Ge{sub 3} crystallizes in the monoclinic space group C2/c with lattice constants a = 12.2261(20) {angstrom}, b = 10.7447(20) {angstrom}, c = 8.4754(17) {angstrom} and {beta} = 110.288(30){sup o} (neutron diffraction data). The crystal structure of Yb{sub 3}Ga{sub 7}Ge{sub 3} is an intergrowth of planar layers of YbGa{sub x}Ge{sub y} and puckered layers of (Ge)n. YbGa{sub 4}Ge{sub 2} crystallizes in a modified PuGa{sub 6} structure type in the tetragonal polar space group I4cm with lattice constants a = b = 5.9874(6) {angstrom} and c = 15.1178(19) {angstrom}. The structure of YbGa{sub 4}Ge{sub 2} is an intergrowth of puckered Ga layers and puckered Ga{sub x}Ge{sub y} layers with Yb atoms residing within the channels formed by the connection of the two layers. Physical properties, resistivity ({rho}), magnetic susceptibility ({chi}) and specific heat (C) were measured for Yb{sub 3}Ga{sub 7}Ge{sub 3}. No magnetic ordering was observed. It was found that at low temperatures, {rho} varied as T{sup 2} and C{alpha}T, indicating Fermi-liquid regime in Yb{sub 3}Ga{sub 7}Ge{sub 3} at low temperatures.

Peter, S. C.; Malliakas, C. D.; Nakotte, H.; Kothapilli, K.; Rayaprol, S.; Schultz, A. J.; Kanatzidis, M. G. (Materials Science Division); ( XSD); (Northwestern Univ.); (Jawaharlal Nehru Centre for Adv. Sci. Res.); (New Mexico State Univ.); (Los Alamos Nat. Lab.); (UGC-DAE Consortium for Sci. Res.)

2012-03-01T23:59:59.000Z

305

Invited Paper GaAs/A1O photonic bandgap material fabrication and characterization  

E-Print Network [OSTI]

semiconductor crystals, photonic crystals do not occur naturally. There are, therefore, several seemingly direct bandgap semiconductors, such as GaAs, A1GaAs, InP, InGaAsP, etc., in which the radiative-dimensional photonic bandgaps for microwave and millimeter-wave radiation, and for shorter optical wavelengths in one

Zhou, Weidong

306

Drift dominated InP/GaP photodiodes Yanning Sun a,*, Aristo Yulius a  

E-Print Network [OSTI]

Drift dominated InP/GaP photodiodes Yanning Sun a,*, Aristo Yulius a , Guohua Li b , Jerry MP photodiodes fabricated on GaP substrate with unique drift dominated design, which can build an electric field throughout the active region by varying the doping concentration. The InP/GaP photodiodes have been grown

Woodall, Jerry M.

307

DISSERTATION DEVICE PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS  

E-Print Network [OSTI]

DISSERTATION DEVICE PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS Submitted by Markus Gloeckler PHYSICS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS BE ACCEPTED AS FULFILLING IN PART REQUIREMENTS OF Cu(In,Ga)Se2 THIN-FILM SOLAR CELLS Thin-film solar cells have the potential to be an important

Sites, James R.

308

Free carrier induced spectral shift for GaAs filled metallic hole arrays  

E-Print Network [OSTI]

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

New Mexico, University of

309

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy  

E-Print Network [OSTI]

Controlled oxygen doping of GaN using plasma assisted molecular-beam epitaxy A. J. Ptak, L. J-assisted molecular-beam epitaxy to study the dependence of oxygen incorporation on polarity and oxygen partial pressure. Oxygen incorporates at a rate ten times faster on nitrogen-polar GaN than on the Ga polarity

Myers, Tom

310

GA Hot Cell D&D Closeout Report  

Office of Legacy Management (LM)

GENERAL ATOMICS GENERAL ATOMICS HOT CELL FACILITY DECONTAMINATION & DECOMMISSIONING PROJECT FINAL PROJECT CLOSEOUT REPORT prepared for GA HOT CELL D&D PROJECT CONTRACT NUMBERS DE-AC03-84SF11962 and DE-AC03-95SF20798 PBS VL-GA-0012 Approvals Prepared by: James Davis, III Date Project Manager, Oakland Environmental Programs Office Reviewed by: John Lee Date Deputy, Oakland Environmental Programs Office Approved by: Laurence McEwen Date Acting Director, Oakland Environmental Programs Office General Atomics Hot Cell Facility D&D Project Closeout Report Contents Page i CONTENTS CONTENTS.....................................................................................................................................

311

Simple intrinsic defects in GaAs : numerical supplement.  

SciTech Connect (OSTI)

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

Schultz, Peter Andrew

2012-04-01T23:59:59.000Z

312

Surface morphology and magnetic anisotropy in (Ga,Mn)As  

E-Print Network [OSTI]

Atomic Force Microscopy and Grazing incidence X-ray diffraction measurements have revealed the presence of ripples aligned along the $[1\\bar{1}0]$ direction on the surface of (Ga,Mn)As layers grown on GaAs(001) substrates and buffer layers, with periodicity of about 50 nm in all samples that have been studied. These samples show the strong symmetry breaking uniaxial magnetic anisotropy normally observed in such materials. We observe a clear correlation between the amplitude of the surface ripples and the strength of the uniaxial magnetic anisotropy component suggesting that these ripples might be the source of such anisotropy.

S. Piano; X. Marti; A. W. Rushforth; K. W. Edmonds; R. P. Campion; O. Caha; T. U. Schulli; V. Holy; B. L. Gallagher

2010-10-01T23:59:59.000Z

313

Operating experience with a GaAs photoemission electron source  

SciTech Connect (OSTI)

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

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

1986-12-01T23:59:59.000Z

314

An investigation on reliable passivation of GaP  

E-Print Network [OSTI]

reports the results of a study of sputtered Silicon Nitride 3N4) and Anodic Oxide as passivating techniques for Gallium Phosphide. Anodic Oxide was grown on GaP by anodizing the semiconductor in 30% hydrogen peroxide. The resulting oxide had an index... reports the results of a study of sputtered Silicon Nitride 3N4) and Anodic Oxide as passivating techniques for Gallium Phosphide. Anodic Oxide was grown on GaP by anodizing the semiconductor in 30% hydrogen peroxide. The resulting oxide had an index...

Greaves King, Carlos A.

2012-06-07T23:59:59.000Z

315

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

Science Journals Connector (OSTI)

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

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

1985-01-01T23:59:59.000Z

316

Recent progress in commensurate-incommensurate phase transformations. [Hg/sub 3/-delta AsF/sub 6/; 2H polytype of TaSe/sub 2/  

SciTech Connect (OSTI)

Three topics are discussed. (1) the nature of long wavelength excitations in Hg/sub 3/-delta AsF/sub 6/, where gapless excitations in addition to the conventional acoustic modes are observed. (2) Thiourea, in which new commensurate phases can be induced by an external electric field. (3) Discommensurations in 2HTaSe/sub 2/, where recent electron diffraction and high resolution x-ray data combine with neutron results to establish a quite complex and subtle behavior. 9 figures.

Axe, J.D.

1982-08-01T23:59:59.000Z

317

Ultralow damage depth by electron cyclotron resonance plasma etching of GaAs/InGaAs quantum wells  

Science Journals Connector (OSTI)

Dry etch induced damage of GaAs/InGaAs/GaAs heterostructures in an electron cyclotron resonance (ECR) argon discharge has been investigated as a function of additional radio frequency self?biasing of the sample and process pressure in argon ECR discharges. We used depth resolved photoluminescence measurements to determine the influence of the etch process on the samples. We observe a decreasing damage depth for smaller bias voltages reaching its lowest value of 1.7 nm at 20 V bias and a pressure of 0.15 Pa. For lower pressures we observe a strong increase of the damage which is attributed predominantly to high energetic vacuum ultraviolet radiation from the ECR region.

T. Bickl; B. Jacobs; J. Straka; A. Forchel

1993-01-01T23:59:59.000Z

318

High-performance broadband optical coatings on InGaN/GaN solar cells for multijunction device integration  

SciTech Connect (OSTI)

We demonstrate InGaN/GaN multiple quantum well solar cells grown by metalorganic chemical vapor deposition on a bulk (0001) substrate with high-performance broadband optical coatings to improve light absorption. A front-side anti-reflective coating and a back-side dichroic mirror were designed to minimize front surface reflections across a broad spectral range and maximize rear surface reflections only in the spectral range absorbed by the InGaN, making the cells suitable for multijunction solar cell integration. Application of optical coatings increased the peak external quantum efficiency by 56% (relative) and conversion efficiency by 37.5% (relative) under 1 sun AM0 equivalent illumination.

Young, N. G., E-mail: ngyoung@engineering.ucsb.edu; Farrell, R. M.; Iza, M.; Speck, J. S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Perl, E. E.; Keller, S. [Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States); Bowers, J. E.; Nakamura, S.; DenBaars, S. P. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 (United States)

2014-04-21T23:59:59.000Z

319

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

SciTech Connect (OSTI)

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

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

2009-06-08T23:59:59.000Z

320

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

Science Journals Connector (OSTI)

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

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

2008-04-28T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

Carrier effective masses in symmetrically strained (GaIn)As/Ga(PAs) multiple-quantum-well structures  

Science Journals Connector (OSTI)

The carrier effective masses in symmetrically strained (GaIn)As/Ga(PAs) multiple-quantum-well heterostructures have been determined as a function of the incorporated compressive strain in the (GaIn)As quantum-well layer by applying magneto-optical studies. The precise structural parameters, i.e., individual layer thicknesses, strain values, and crystalline perfection, have been determined independently by high-resolution x-ray diffraction and transmission electron microscopy. By analyzing both the allowed and forbidden optical transitions as a function of the magnetic field, detected by polarization-dependent magnetophotoluminescence excitation spectroscopy, the exciton binding energy as well as the effective in-plane electron and heavy-hole masses have been determined quantitatively as a function of strain. The theoretically predicted significant decrease of the in-plane heavy-hole mass with increasing strain has been observed. The obtained results are discussed and compared with the contradictory results reported in the literature.

M. Volk; S. Lutgen; T. Marschner; W. Stolz; E. O. Göbel; P. C. M. Christianen; J. C. Maan

1995-10-15T23:59:59.000Z

322

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

323

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

SciTech Connect (OSTI)

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

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

2010-12-13T23:59:59.000Z

324

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

325

Structure of negatively charged muonium in n-type GaAs  

Science Journals Connector (OSTI)

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

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

1995-05-15T23:59:59.000Z

326

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

E-Print Network [OSTI]

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

Chen, Zhi

327

INCREASED CELL EFFICIENCY IN InGaAs THIN FILM SOLAR CELLS WITH DIELECTRIC AND METAL BACK REFLECTORS  

E-Print Network [OSTI]

INCREASED CELL EFFICIENCY IN InGaAs THIN FILM SOLAR CELLS WITH DIELECTRIC AND METAL BACK REFLECTORS solar cells using back reflectors. We studied absorption enhancement in InGaAs and InGaAsP thin film and metal, on InGaAs thin film solar cell performance by device modeling and nu- merical simulations. DEVICE

Atwater, Harry

328

Optical phonon modes in InGaN/GaN dot-in-a-wire heterostructures grown by molecular beam epitaxy  

SciTech Connect (OSTI)

We report on the studies of optical phonon modes in nearly defect-free GaN nanowires embedded with intrinsic InGaN quantum dots by using oblique angle transmission infrared spectroscopy. These phonon modes are dependent on the nanowire fill-factor, doping densities of the nanowires, and the presence of InGaN dots. These factors can be applied for potential phonon based photodetectors whose spectral responses can be tailored by varying a combination of these three parameters. The optical anisotropy along the growth (c-) axis of the GaN nanowire contributes to the polarization agility of such potential photodetectors.

Titus, J.; Perera, A. G. U. [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States)] [Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303 (United States); Nguyen, H. P. T.; Mi, Z. [Department of Electrical and Computer Engineering, McGill University, Montreal, Quebec H3A 2A7 (Canada)] [Department of Electrical and Computer Engineering, McGill University, Montreal, Quebec H3A 2A7 (Canada)

2013-03-25T23:59:59.000Z

329

GA103 a microprogrammable processor for online filtering  

E-Print Network [OSTI]

GA103 is a 16 bit microprogrammable processor, which emulates the PDP 11 instruction set. It is based on the Am2900 slices. It allows user- implemented microinstructions and addition of hardwired processors. It will perform online filtering tasks in the NA14 experiment at CERN, based on the reconstruction of transverse momentum of photons detected in a lead glass calorimeter. (3 refs).

Calzas, A; Danon, G

1981-01-01T23:59:59.000Z

330

1ACM SIGCSE'14, Atlanta, GA Using Gamification in Technical  

E-Print Network [OSTI]

1ACM SIGCSE'14, Atlanta, GA Using Gamification in Technical Higher Education: An XP Report. Epema, An Experience Report on Using Gamification in Technical Higher Education, ACM SIGCSE'14. http's not you, it's me · New ambition of GamificationU (Top-20 Eng/Tech*) ·

Iosup, Alexandru

331

Response of GaAs to fast intense laser pulses  

E-Print Network [OSTI]

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

Graves, JS; Allen, Roland E.

1998-01-01T23:59:59.000Z

332

Recombination in Low-Bandgap InGaAs  

SciTech Connect (OSTI)

We review our investigation of recombination in In{sub x}Ga{sub 1-x}As with indium concentrations ranging between x=0.53 (i.e., lattice-matched to InP) and x=0.78. External radiative efficiency measurements were used to study how defect-related and Auger mechanisms compete with radiative recombination. The results indicated that deep mid-gap levels facilitate defect-related recombination in lattice-matched InGaAs while shallower levels play a more important role in the indium-rich alloys. Subsequent sub-bandgap photoluminescence measurements confirmed the presence of deep levels in the lattice-matched InGaAs. The superlinear excitation dependence of the sub-gap emission led to a defect-related deep-donor/shallow-acceptor pair model. Recent cathodoluminescence measurements of the subgap transitions show no spatial contrast, supporting the assignment of this mechanism to evenly distributed point defects. We hypothesize that the deep states observed in lattice-matched InGaAs are related to imperfections in the incorporation of indium or gallium, which become less likely as the indium concentration is increased.

Gfroerer, T. H.; Wanlass, M. W.

2006-01-01T23:59:59.000Z

333

High-quality InP on GaAs  

E-Print Network [OSTI]

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

Quitoriano, Nathaniel Joseph

2006-01-01T23:59:59.000Z

334

MOCVD Growth of AlGaInN for UV Emitters  

SciTech Connect (OSTI)

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

Crawford, Mary; Han, Jung

1999-07-07T23:59:59.000Z

335

[Ta{sub 6}Cl{sub 12}(PrCN){sub 6}][(Ta{sub 6}Cl{sub 12})Cl{sub 6}]{center{underscore}dot}2PrCn, a compound with homonuclear mixed-charge cluster units [Ta{sub 6}Cl{sub 12}]{sup 2+} and [Ta{sub 6}Cl{sub 12}]{sup 4+}  

SciTech Connect (OSTI)

In transition metal cluster chemistry, compounds consisting of both a cluster cation and a cluster anion are not very common. The first members of this type of compound of the composition [M{sub 6}X{sub 12}(EtOH){sub 6}][(Mo{sub 6}Cl{sub 8})Cl{sub 4}X{sub 2}]{center{underscore}dot}mEtOH{center{underscore}dot}nEt{sub 2}O (M = Nb, Ta; X = Cl, Br) have been recently prepared. Crystal structure determinations for [Nb{sub 6}Cl{sub 12}(EtOH){sub 6}][(Mo{sub 6}Cl{sub 8})Cl{sub 6}]{center{underscore}dot}3EtOH{center{underscore}dot}3Et{sub 2}O and [Ta{sub 6}Cl{sub 12}(EtOH){sub 6}][(Mo{sub 6}Cl{sub 8})Cl{sub 6}]{center{underscore}dot}6EtOH revealed the presence of two different hexanuclear cluster cores; namely, the [M{sub 6}X{sub 12}(EtOH){sub 6}]{sup 2+} cluster cations and the [(Mo{sub 6}Cl{sub 8})Cl{sub 4}X{sub 2}]{sup 2{minus}} cluster anions. In fact, these compounds consist of two different heteronuclear cluster units with different charges: [M{sub 6}X{sub 12}]{sup 2+} in the cation and [Mo{sub 6}Cl{sub 8}]{sup 4+} in the anion. The preparation of cation-anion pairs with homonuclear mixed-charge cluster units is also possible. In the present study, the synthesis and crystal structure of the cluster pair [Ta{sub 6}Cl{sub 12}(PrCN){sub 6}][(Ta{sub 6}Cl{sub 12})Cl{sub 6}]{center{underscore}dot}2PrCN is reported. The compound is built of two octahedral homonuclear mixed-charge cluster units: [Ta{sub 6}Cl{sub 12}]{sup 2+} in the [Ta{sub 6}Cl{sub 12}(PrCN){sub 6}]{sup 2+} cluster cation and [Ta{sub 6}Cl{sub 12}]{sup 4+} in the [(Ta{sub 6}Cl{sub 12})Cl{sub 6}]{sup 2{minus}} cluster anion.

Brnicevic, N.; Sirac, S.; Basic, I.; Zhang, Z.; McCarley, R.E.; Guzei, I.A.

1999-09-06T23:59:59.000Z

336

Cn2 and wind profiler method to quantify the frozen flow decay using wide-field laser guide stars adaptive optics  

E-Print Network [OSTI]

We use spatio-temporal cross-correlations of slopes from five Shack-Hartmann wavefront sensors to analyse the temporal evolution of the atmospheric turbulence layers at different altitudes. The focus is on the verification of the frozen flow assumption. The data is coming from the Gemini South Multi-Conjugate Adaptive Optics System (GeMS). First, the Cn2 and wind profiling technique is presented. This method provides useful information for the AO system operation such as the number of existing turbulence layers, their associated velocities, altitudes and strengths and also a mechanism to estimate the dome seeing contribution to the total turbulence. Next, by identifying the turbulence layers we show that it is possible to estimate the rate of decay in time of the correlation among turbulence measurements. We reduce on-sky data obtained during 2011, 2012 and 2013 campaigns and the first results suggest that the rate of temporal de-correlation can be expressed in terms of a single parameter that is independent ...

Guesalaga, Andrés; Cortes, Angela; Béchet, Clémentine; Guzmán, Dani

2014-01-01T23:59:59.000Z

337

Caractrisation en bruit des photodiodes P.I.N. Hg1-x Cdx Te 03BB = B. Orsal (*), R. Alabedra (*), C. Maille (*), C. Boisrobert (**), D. Morvan (**), J. Meslage (***) et  

E-Print Network [OSTI]

63 Caractérisation en bruit des photodiodes P.I.N. Hg1-x Cdx Te à 03BB = 1,3 03BCm B. Orsal (*), R montrent que la qualité des contacts des photodiodes de 2e génération est meilleure que celle obtenue sur.I.N. Hg1-xCdxTe photodiodes at 03BB = 1.3 03BCm by measurements of 1/f noise. The devices are manufactured

Paris-Sud XI, Université de

338

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

E-Print Network [OSTI]

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

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

1997-01-01T23:59:59.000Z

339

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

E-Print Network [OSTI]

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

340

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

Note: This page contains sample records for the topic "hg cn 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

Multi-Pollutant Emissions Control: Pilot Plant Study of Technologies for Reducing Hg, SO3, NOx and CO2 Emissions  

SciTech Connect (OSTI)

A slipstream pilot plant was built and operated to investigate technology to adsorb mercury (Hg) onto the existing particulate (i.e., fly ash) by cooling flue gas to 200-240 F with a Ljungstrom-type air heater or with water spray. The mercury on the fly ash was then captured in an electrostatic precipitator (ESP). An alkaline material, magnesium hydroxide (Mg(OH){sub 2}), is injected into flue gas upstream of the air heater to control sulfur trioxide (SO{sub 3}), which prevents acid condensation and corrosion of the air heater and ductwork. The slipstream was taken from a bituminous coal-fired power plant. During this contract, Plant Design and Construction (Task 1), Start Up and Maintenance (Task 2), Baseline Testing (Task 3), Sorbent Testing (Task 4), Parametric Testing (Task 5), Humidification Tests (Task 6), Long-Term Testing (Task 7), and a Corrosion Study (Task 8) were completed. The Mercury Stability Study (Task 9), ESP Report (Task 11), Air Heater Report (Task 12) and Final Report (Task 14) were completed. These aspects of the project, as well as progress on Public Outreach (Task 15), are discussed in detail in this final report. Over 90% mercury removal was demonstrated by cooling the flue gas to 200-210 F at the ESP inlet; baseline conditions with 290 F flue gas gave about 26% removal. Mercury removal is sensitive to flue gas temperature and carbon content of fly ash. At 200-210 F, both elemental and oxidized mercury were effectively captured at the ESP. Mg(OH){sub 2} injection proved effective for removal of SO{sub 3} and eliminated rapid fouling of the air heater. The pilot ESP performed satisfactorily at low temperature conditions. Mercury volatility and leaching tests did not show any stability problems. No significant corrosion was detected at the air heater or on corrosion coupons at the ESP. The results justify larger-scale testing/demonstration of the technology. These conclusions are presented and discussed in two presentations given in July and September of 2005 and are included in Appendices E and F.

Michael L. Fenger; Richard A. Winschel

2005-08-31T23:59:59.000Z

342

GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer,1,a  

E-Print Network [OSTI]

GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer,1,a Daniel C Richard R. King,2 and Harry A. Atwater1 1 California Institute of Technology, Pasadena, California 91125, USA 2 Spectrolab, Inc., Sylmar, California 91342, USA 3 Aonex Technologies, Pasadena, California 91106

Atwater, Harry

343

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

344

The evolution of Ga and As core levels in the formation of Fe/GaAs (001):A high resolution soft x-ray photoelectron spectroscopic study  

SciTech Connect (OSTI)

A high resolution soft x-ray photoelectron spectroscopic study of Ga and As 3d core levels has been conducted for Fe/GaAs (001) as a function of Fe thickness. This work has provided unambiguous evidence of substrate disrupting chemical reactions induced by the Fe overlayer--a quantitative analysis of the acquired spectra indicates significantly differing behavior of Ga and As during Fe growth, and our observations have been compared with existing theoretical models. Our results demonstrate that the outdiffusing Ga and As remain largely confined to the interface region, forming a thin intermixed layer. Whereas at low coverages Fe has little influence on the underlying GaAs substrate, the onset of substrate disruption when the Fe thickness reaches 3.5 Angstrom results in major changes in the energy distribution curves (EDCs) of both As and Ga 3d cores. Our quantitative analysis suggests the presence of two additional As environments of metallic character: one bound to the interfacial region and another which, as confirmed by in situ oxidation experiments, surface segregates and persists over a wide range of overlayer thickness. Analysis of the corresponding Ga 3d EDCs found not two, but three additional environments--also metallic in nature. Two of the three are interface resident whereas the third undergoes outdiffusion at low Fe coverages. Based on the variations of the integrated intensities of each component, we present a schematic of the proposed chemical makeup of the Fe/GaAs (001) system.

Thompson, Jamie; Neal, James; Shen, Tiehan; Morton, Simon; Tobin, James; Waddill, George Dan; Matthew, Jim; Greig, Denis; Hopkinson, Mark

2008-07-14T23:59:59.000Z

345

Band-filling effect on the light emission spectra of InGaN/GaN quantum wells with highly doped barriers  

Science Journals Connector (OSTI)

We investigate spectra of InGaN/GaN quantum well (QW) light-emitting diode (LED) structures with heavily doped barriers at different excitation levels. We model the spectral shape and energy position in frames of dominating mechanism of free electron ... Keywords: Band filling, Doped barriers, Emission spectra, Quantum well

B. Arnaudov; D. S. Domanevskii; S. Evtimova; Ch. Ivanov; R. Kakanakov

2009-02-01T23:59:59.000Z

346

Effects of internal fields on deep-level emission in InGaN/GaN quantum-well light-emitting diodes  

Science Journals Connector (OSTI)

We report on the important role played by internal quantum well (QW) fields in the anomalous inversion of capacitance transients in InGaN/GaN multi-QW light-emitting diodes (LEDs). This effect was observed by deep-level transient spectroscopy (DLTS) ... Keywords: Deep level, III-Nitride, Internal fields, Quantum well

L. Rigutti; A. Castaldini; A. Cavallini

2009-02-01T23:59:59.000Z

347

Light output enhancement of InGaN/GaN light-emitting diodes with contrasting indium tin-oxide nanopatterned structures  

Science Journals Connector (OSTI)

Various nanopatterns on the transparent conducting indium tin oxide (ITO) layer are investigated to enhance the light extraction efficiency of the InGaN/GaN light-emitting diodes (LEDs). Triangular, square, and circular nanohole patterns with the square ...

Sang Hyun Jung; Keun Man Song; Young Su Choi; Hyeong-Ho Park; Hyun-Beom Shin; Ho Kwan Kang; Jaejin Lee

2013-01-01T23:59:59.000Z

348

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

Science Journals Connector (OSTI)

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

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

2008-03-01T23:59:59.000Z

349

Exciton diamagnetic shift in GaAs/Ga1-xAlxAs quantum wells under in-plane magnetic fields  

Science Journals Connector (OSTI)

Using a variational procedure in the effective-mass and parabolic-band approximations we investigate the effects of in-plane magnetic fields on the exciton states in single GaAs/Ga1-xAlxAs quantum wells. Exciton properties ... Keywords: 71.55.Eq, 73.20.Mf, 73.21.Fg, Diamagnetic shifts, Magnetoexcitons, Quantum wells

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

2008-03-01T23:59:59.000Z

350

Determination of70Ge(n,p)70Ga and74Ge(n,p)74Ga reaction cross sections for a fission neutron spectrum  

Science Journals Connector (OSTI)

The fission neutron spectrum averaged cross-sections for the reactions70Ge(n,p)70Ga and74Ge(n,p)74Ga have been determined. The averages of four determinations are, respectively, (3.10±0.30) mb and (0.00938±0.0005...

I. M. Cohen; A. J. Kestelman; J. C. Furnari…

1996-03-14T23:59:59.000Z

351

Chemical and physical properties of gas jets in comets: II. Modeling OH, CN and C2 jets in Comet C/1995 O1 (Hale–Bopp) one month after perihelion  

Science Journals Connector (OSTI)

We present an analysis of OH, CN, and C2 jets observed in Comet Hale–Bopp during April 22–26, 1997. We conclude that an extended source, which peaks in productivity after a certain amount of time has passed after being released from the nucleus (8.5, 2.5, and 42.6 × 10 4   s , respectively) is responsible for the observed coma jet morphology in all three species. Sub-micron organic grains are the favored explanation for the extended source. Our models indicate that this extended source produces approximately 40% of the OH, 50% of the C2, and 75% of the CN. The balance for each species is created by a diffuse nuclear gas source. Compared with the nuclear gas source and normalized to the CN abundance, the composition of the extended source is depleted in OH by a factor of ?6, and depleted in C2 by a factor of ?2. The existence of anti-sunward jets do not require production of radicals throughout the cometary night. Instead, our model demonstrates that active areas exposed to near-twilight conditions throughout the comet's rotational period can produce the observed anti-sunward morphology.

S.M. Lederer; H. Campins; D.J. Osip

2009-01-01T23:59:59.000Z

352

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

SciTech Connect (OSTI)

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

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

2013-11-25T23:59:59.000Z

353

Acceptor and donor production in Hg b1 s[subscript -x]Cd[subscript x]Te by neutron transmutation doping  

E-Print Network [OSTI]

remains constant during the irradiation, 4. The dopant or oduced i'rom the decay of the pr oduct isot. ope is stable, 5. The effect of bur nup of the product isotopes and the dopants is negligible. With these assumptions and approximations one has... amounts such as Te and Te, and with products arri tting gamma rays with approximately the same ener gy, theoretical methods wer e developed for deter mining acceptor and donor production levels in Hg& xCdxTe based on the simultaneous irradiation of a...

Seager, Kevin Douglas

1985-01-01T23:59:59.000Z

354

Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg.sup.196 enrichment  

DOE Patents [OSTI]

The present invention is directed to a method of eliminating the cold spot zones presently used on Hg.sup.196 isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment.

Grossman, Mark W. (Belmont, MA)

1993-01-01T23:59:59.000Z

355

Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg[sup 196] enrichment  

DOE Patents [OSTI]

The present invention is directed to a method of eliminating the cold spot zones presently used on Hg[sup 196] isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment.

Grossman, M.W.

1993-02-16T23:59:59.000Z

356

Electroreflectance study of the temperature dependence of the E 1 transition of Hg0.65Cd0.35Te  

Science Journals Connector (OSTI)

We have investigated the temperature dependence of the E 1 optical feature (energy and broadening parameter) of Hg0.65Cd0.35Te using electroreflectance in the metal?insulator?semiconductor configuration. Measurements were made in the temperature range 77–293 K. The observed variation can be fit by either a linear dependence or the empirical Varshni relation [Y.P. Varshni Physica (Utrecht) 3 9 149 (1967)] within experimental error. The obtained linear temperature coefficient for E 1 is compared with previous results. The temperature dependence of the broadening parameter also is discussed.

A. Ksendzov; Fred. H. Pollak; J. A. Wilson; V. A. Cotton

1989-01-01T23:59:59.000Z

357

Dynamic Model of Hydrogen in GaN  

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

Dynamic Model of Hydrogen in GaN by S. M. Myers and A. F. Wright Motivation-Hydrogen is incorporated into p-type GaN during MOCVD growth, producing highly stable passivation of the Mg acceptors. Complete acceptor activation by thermal H release requires temperatures that threaten material integrity, prompting compromises in device processing. At lower temperatures, forward bias of p-n junctions or electron-beam irradiation produces a metastable, reversible activation without H release. To understand and control such effects, we are developing a mathematical model of H behavior wherein state energies from density-functional theory are employed in diffusion-reaction equations. Previously, we used the greatly simplifying assumptions of local equilibrium among states

358

CN ENGINEERING CHALLENGES David Ferryman  

E-Print Network [OSTI]

fewer train delays ­ Need better wayside equipment to catch cars before they leave terminals to increase car loadings from 286,000 lb. to 315,000 lb. and beyond. ­ Will need better track and bridges of derailments ­ Need improved defect detection in rail and welds ­ Need higher speed rail flaw detection RFD

Barkan, Christopher P.L.

359

GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy  

SciTech Connect (OSTI)

Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

Kuang, Y. J. [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Physics, University of California, San Diego, La Jolla, California 92093 (United States); Yu, K. M.; Walukiewicz, W. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kudrawiec, R. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institute of Physics, Wroclaw University of Technology, Wybrzeze, Wyspianskiego 27, 50-370 Wroclaw (Poland); Luce, A. V. [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Electronic Materials Program, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Ting, M. [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)] [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States); Tu, C. W. [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)] [Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

2013-03-18T23:59:59.000Z

360

Ga configurations in hydrogenated amorphous silicon as studied by x-ray photoemission spectroscopy  

Science Journals Connector (OSTI)

Samples of crystalline silicon and glow-discharge-deposited hydrogenated amorphous silicon were doped with gallium by low-energy (4-keV) ion implantation. X-ray photoemission spectroscopy was used to study the chemical-bonding states of the Ga. From Ga 3d core-level studies, we found that elementary interstitial, threefold-coordinated, and fourfold-coordinated Ga coexist in the ion-implanted and annealed amorphous silicon network. The percentage of activated threefold- and fourfold-coordinated Ga atoms is found to increase with increasing annealing temperature, prior to crystallization. The energy released by the amorphous silicon lattice upon annealing contributes to the activation of the gallium from the elementary state to the threefold- or fourfold-coordinated state. No evidence of Ga-H bond formation is found. The percentage of fourfold-coordinated Ga, which we call the doping efficiency, ranges from 5% to 10%, depending upon the thermal treatment.

Z. H. Lu; S. Poulin-Dandurand; E. Sacher; A. Yelon

1990-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

Accurate characterization and improvement of GaAs microstrip attenuation  

E-Print Network [OSTI]

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

Carroll, James Mason

2012-06-07T23:59:59.000Z

362

InGaAsSb thermophotovoltaic diode physics evaluation  

SciTech Connect (OSTI)

The hotside operating temperatures for many projected thermophotovoltaic (TPV) conversion system applications are approximately 1,000 C, which sets an upper limit on the TPV diode bandgap of 0.6 eV from efficiency and power density considerations. This bandgap requirement has necessitated the development of new diode material systems, never previously considered for energy generation. To date, InGaAsSb quaternary diodes grown lattice-matched on GaSb substrates have achieved the highest performance. This report relates observed diode performance to electro-optic properties such as minority carrier lifetime, diffusion length and mobility and provides initial links to microstructural properties. This analysis has bounded potential diode performance improvements. For the 0.52 eV InGaAsSb diodes used in this analysis the measured dark current is 2 {times} 10{sup {minus}5} A/cm{sup 2}, versus a potential Auger limit 1 {times} 10{sup {minus}5} A/cm{sup 2}, a radiative limit of 2 {times} 10{sup {minus}6} A/cm{sup 2} (no photon recycling), and an absolute thermodynamic limit of 1.4 {times} 10{sup {minus}7} A/cm{sup 2}. These dark currents are equivalent to open circuit voltage gains of 20 mV (7%), 60 mV (20%) and 140 mV (45%), respectively.

Charache, G.W.; Baldasaro, P.F.; Danielson, L.R. [Lockheed-Martin, Inc., Schenectady, NY (United States)] [and others

1998-06-01T23:59:59.000Z

363

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

Science Journals Connector (OSTI)

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

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

1986-03-15T23:59:59.000Z

364

Synthesis and Structure of Sr3GaN3 and Sr6GaN5:? Strontium Gallium Nitrides with Isolated Planar [GaN3]6- Anions  

Science Journals Connector (OSTI)

Synthesis and Structure of Sr3GaN3 and Sr6GaN5:? Strontium Gallium Nitrides with Isolated Planar [GaN3]6- Anions ... 9-19 In most cases, an alkaline earth metal is introduced into a Na melt to enhance the solubility of nitrogen, and is incorporated in the nitride product. ... The container was sealed by welding its open end in an argon atmosphere with active water-cooling so that NaN3 did not decompose due to heating during the welding. ...

Dong Gon Park; Zoltán A. Gál; Francis J. DiSalvo

2003-02-13T23:59:59.000Z

365

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

366

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

SciTech Connect (OSTI)

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

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

1990-01-01T23:59:59.000Z

367

Photoluminescence kinetics of indirect excitons in GaAs/AlxGa1-xAs coupled quantum wells  

Science Journals Connector (OSTI)

Photoluminescence (PL) kinetics of long-lifetime indirect excitons in a GaAs/AlxGa1-xAs coupled quantum well characterized by a small in-plane random potential was studied at temperatures 1.5<~T<~15 K for a wide range of exciton densities. Strong deviations of the indirect exciton PL kinetics from monoexponential PL rise/decay were observed at low temperatures and high exciton densities. In particular, right after the excitation is switched off, the spectrally integrated indirect exciton PL intensity increased sharply. Simultaneously, the indirect exciton energy distribution was observed to narrow significantly. The observed increase in intensity is attributed to the sharp increase of occupation of the optically active exciton states. The energy distribution narrowing is explained in terms of the phonon mediated exciton energy relaxation in momentum space and in the in-plane random potential.

L. V. Butov, A. Imamoglu, A. V. Mintsev, K. L. Campman, and A. C. Gossard

1999-01-15T23:59:59.000Z

368

Sensitivity of absorption spectra to surface segregation in InGaN/GaN quantum well structures  

SciTech Connect (OSTI)

We investigate the influence of the indium surface segregation on absorption spectra in InGaN/GaN quantum well structures having different indium amount. Results of the mathematical modeling show that such influence is more pronounced in quantum well structures with high indium amounts. The origin of this effect is related to the interplay between the indium surface segregation and internal electrostatic fields. Our theoretical analysis is performed using semiconductor Bloch equations within the Hartree-Fock approximation including into consideration excitonic effects. Results of the global sensitivity analysis evidence that the influence of the indium surface segregation is less than one order of magnitude in comparison with the impact of the quantum-well width and indium molar fraction. Also, the influence of the indium surface segregation is not the same for each interface of the quantum well.

Klymenko, M. V.; Shulika, O. V. [Lab. Photonics, Kharkov National University of Radio Electronics, Kharkov, 61166 (Ukraine); Sukhoivanov, I. A. [Department of Electronics, Engineering Division, University of Guanajuato, Salamanca, Guanajuato, 36885 (Mexico)

2014-05-15T23:59:59.000Z

369

Band offsets from two special GaAs-AlxGa1-xAs quantum-well structures  

Science Journals Connector (OSTI)

Half-parabolic quantum wells and two-stepped quantum wells have been grown by molecular-beam epitaxy with the GaAs-AlxGa1-xAs system and investigated by photoluminescence techniques to determine the band offsets at the heterointerfaces. Both structures provide interband transitions that are sensitive to the partitioning of the energy-gap discontinuity ?Eg=?Ec+?Ev between the conduction and valence bands. It is concluded that the data require valence-band offsets ?Ev equal to 38% and 41% of ?Eg for the half-parabolic wells and the two-stepped wells, respectively. These band offsets are therefore in agreement with the trend of other recent determinations.

R. C. Miller; A. C. Gossard; D. A. Kleinman

1985-10-15T23:59:59.000Z

370

ArF laser-based quantum well intermixing in InGaAs/InGaAsP heterostructures  

SciTech Connect (OSTI)

Radiation from a 193 nm ArF laser was investigated to modify surface properties of InGaAs/InGaAsP quantum well (QW) heterostructures and introduce defects required to enhance intermixing during the annealing process. A top 200 nm thick sacrificial layer of InP served as a reservoir for laser generated defects. The irradiation with up to 90 pulses at 65-150 mJ/cm{sup 2} allowed to generate an array of 1.2x1 mm{sup 2} sites of QW intermixed material, with bandgap energy blueshifted up to 107 nm. We discuss the mechanism and advantages of this approach for postgrowth wafer level fabrication of multibandgap QW material.

Genest, Jonathan; Beal, Romain; Aimez, Vincent; Dubowski, Jan J. [Department of Electrical and Computer Engineering, Center of Excellence for Information Engineering, Universite de Sherbrooke, Sherbrooke, Quebec J1K 2R1 (Canada)

2008-08-18T23:59:59.000Z

371

E-Print Network 3.0 - algorithm ga technique Sample Search Results  

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

for: algorithm ga technique Page: << < 1 2 3 4 5 > >> 1 GAMMA: Global Arrays Meets MATLAB Rajkiran Panuganti Summary: is a straightforward implementa- tion of a standard...

372

Band-structure analysis from photoreflectance spectroscopy in (Ga,Mn)As  

SciTech Connect (OSTI)

Modulation photoreflectance spectroscopy has been applied to study the band-structure evolution in (Ga,Mn)As epitaxial layers with increasing Mn content. Structural and magnetic properties of the layers were characterized with high-resolution X-ray diffractometry and SQUID magnetometery, respectively. The revealed results of decrease in the band-gap-transition energy in the (Ga,Mn)As layers with increasing Mn content are interpreted in terms of a disordered valence band, extended within the band gap, formed, in highly Mn-doped (Ga,Mn)As, as a result of merging the Mn-related impurity band with the host GaAs valence band.

Yastrubchak, Oksana; Gluba, Lukasz; Zuk, Jerzy [Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin (Poland); Wosinski, Tadeusz; Andrearczyk, Tomasz; Domagala, Jaroslaw Z. [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw (Poland); Sadowski, Janusz [Institute of Physics, Polish Academy of Sciences, 02-668 Warsaw, Poland and MAX-Lab, Lund University, 22100 Lund (Sweden)

2013-12-04T23:59:59.000Z

373

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

Science Journals Connector (OSTI)

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

David Richards; Dmitry Zemlyanov; Albena Ivanisevic

2010-02-03T23:59:59.000Z

374

Interface Reactions and Electrical Characteristics of Au/GaSb Contacts  

SciTech Connect (OSTI)

The reaction of Au with GaSb occurs at a relatively low temperature (100 C). Upon annealing, a AuSb{sub 2} compound and several Au-Ga phases are produced. Phase transitions occur toward higher Ga concentration with increasing annealing temperatures. Furthermore, the depth of the contact also increases with increased annealing temperature. They found that the AuSb{sub 2} compound forms on the GaSb surface, with the compound crystal partially ordered with respect to the substrate. The transition of Schottky- to ohmic-contact behavior in Au/n-type GaSb occurs simultaneously with the formation of the AuGa compound at about a 250 C annealing temperature. This ohmic contact forms without the segregation of dopants at the metallic compound/GaSb interface. Therefore it is postulated that transition from Schottky- to ohmic-contact behavior is obtained through a series of tunneling transitions of electrons through defects in the depletion region in the Au/n-type GaSb contacts. Contact resistivities of 6-7 x 10{sup -6} {Omega}-cm{sup 2} were obtained with the annealing temperature between 300 and 350 C for 30 seconds. In Au/p-type GaSb contacts, the resistivity was independent of the annealing temperature. This suggested that the carrier transport in p-type contact dominated by thermionic emission.

H. Ehsani; R.J. Gutmann; G.W. Charache

2000-07-07T23:59:59.000Z

375

Si in GaN -- On the nature of the background donor  

SciTech Connect (OSTI)

A characterization of the Si impurity in GaN is performed by Raman spectroscopy. Applying hydrostatic pressure up to 25 GPa the authors study the behavior of the LO phonon-plasmon mode in a series of high mobility Si doped GaN films. In contrast to earlier results on unintentionally doped bulk GaN crystals no freeze out of the free carriers could be observed in Si doped samples. The authors find that Si is a shallow hydrogenic donor throughout the pressure range studied. This result positively excludes Si incorporation as a dominant source of free electrons in previously studied bulk GaN samples.

Wetzel, C.; Chen, A.L.; Suski, T.; Ager, J.W. III; Walukiewicz, W. [Lawrence Berkeley National Lab., CA (United States). Materials Science Div.

1996-08-01T23:59:59.000Z

376

Structural defects in GaN revealed by Transmission Electron Microscopy  

SciTech Connect (OSTI)

This paper reviews the various types of structural defects observed by Transmission Electron Microscopy in GaN heteroepitaxial layers grown on foreign substrates and homoepitaxial layers grown on bulk GaN substrates. The structural perfection of these layers is compared to the platelet self-standing crystals grown by High Nitrogen Pressure Solution. Defects in undoped and Mg doped GaN are discussed. Some models explaining the formation of inversion domains in heavily Mg doped layers that are possible defects responsible for the difficulties of p-doping in GaN are also reviewed.

Liliental-Weber, Zuzanna

2014-04-18T23:59:59.000Z

377

The influence of the magnetic field on the effect of drag of electrons by phonons in n-Cd{sub x}Hg{sub 1-x}Te  

SciTech Connect (OSTI)

Thermopower in n-Cd{sub 0.2}Hg{sub 0.8}Te (6-100 K) is studied. A large effect of drag of the charge carriers by phonons {alpha}{sub ph} is found. The influence of the magnetic field H on the drag thermopower is considered. It is established that the magnetic field exerts the effect mainly on the electron component of {alpha}{sub ph}. The data are interpreted in the context of the theory taking into account the effect of H on thermopower {alpha}{sub ph}, in which parameter A({epsilon}) proportional to the static force of the drag effect is introduced. By the experimental data {alpha}{sub ph}(T, H), T, and H dependences A({epsilon}) are determined. It is shown that, as H increases, A({epsilon}) sharply decreases. This explains a decrease in {alpha}{sub ph} in the magnetic field, power index k in dependence {alpha}{sub ph} {proportional_to} T{sup -}{kappa}, and narrowing the region of manifestation of the drag effect. It is established that at classically high fields, the drag effect in n-Cd{sub 0.2}Hg{sub 0.8}Te does not vanish.

Aliyev, S. A.; Zulfigarov, E. I.; Selim-Zade, R. I.; Agayev, Z. F., E-mail: agayevz@rambler.ru [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)

2009-09-15T23:59:59.000Z

378

Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal  

SciTech Connect (OSTI)

The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR.

Nick Degenstein; Minish Shah; Doughlas Louie

2012-05-01T23:59:59.000Z

379

Composition and temperature-induced effects on the phonon spectra of narrow-band-gap Hg1-xCdxTe  

Science Journals Connector (OSTI)

Compositional and temperature-dependent Raman and infrared spectroscopies on the narrow-band-gap II-VI alloy, Hg1-xCdxTe (0?x?0.29), are reported in this paper. Raman measurements over this composition range confirm the two-mode behavior of the optical phonons in the alloy, with the frequency positions exhibiting a monotonic change with the alloy composition x. A resonant enhancement of the HgTe-like forbidden longitudinal-optic mode is observed near the E1 band gap of the alloy. Alloy induced perturbations on the electronic states lead to a smearing and a weakening of the resonance with increasing alloy composition. The optical phonons in this small band-gap alloy exhibit anomalous frequency shifts as a function of temperature vis-à-vis normal wide-band-gap semiconductors. This anomaly is attributed to the strong electron-phonon interaction in narrow-band-gap systems, which overshadows the dominant anharmonic (phonon-phonon) interaction in usual semiconductors. A detailed compositional dependent second-order Raman spectra is also reported.

Shyama Rath, K. P. Jain, S. C. Abbi, C. Julien, and M. Balkanski

1995-12-15T23:59:59.000Z

380

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

Science Journals Connector (OSTI)

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

I García; I Rey-Stolle; C Algora

2012-01-01T23:59:59.000Z

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381

Growth of 5 mm GaN Single Crystals at 750 °C from an Na?Ga Melt  

Science Journals Connector (OSTI)

Laser diodes using GaN-based III?V nitrides have been developed, and nitride semiconductor devices are now of considerable interest. ... When the inclusions were exposed to air, they reacted with water vapor in air and produced sodium hydroxide and small gallium metal droplets at the fracture surface of the crystal. ... The solubility of nitrogen in liquid sodium is extremely low (7.1 × 10-9 mol % N at 600 °C). ...

Masato Aoki; Hisanori Yamane; Masahiko Shimada; Seiji Sarayama; Francis J. DiSalvo

2001-02-03T23:59:59.000Z

382

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

383

Local indium segregation and band structure in high efficiencygreen light emitting InGaN/GaN diodes  

SciTech Connect (OSTI)

GaN/InGaN light emitting diodes (LEDs) are commercialized for lighting applications because of the cost efficient way that they produce light of high brightness. Nevertheless, there is significant room for improving their external emission efficiency from typical values below 10 percent to more than 50 percent, which are obtainable by use of other materials systems that, however, do not cover the visible spectrum. In particular, green-light emitting diodes fall short in this respect, which is troublesome since the human eye is most sensitive in this spectral range. In this letter advanced electron microscopy is used to characterize indium segregation in InGaN quantum wells of high-brightness, green LEDs (with external quantum efficiency as high as 15 percent at 75 A/cm2). Our investigations reveal the presence of 1-3 nm wide indium rich clusters in these devices with indium concentrations as large as 0.30-0.40 that narrow the band gap locally to energies as small as 2.65 eV.

Jinschek, Joerg R.; Erni, Rolf; Gardner, Nathan F.; Kim, AndrewY.; Kisielowski, Christian

2004-11-23T23:59:59.000Z

384

Deep Levels in p-Type InGaAsN Lattice Matched to GaAs  

SciTech Connect (OSTI)

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

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

1999-03-02T23:59:59.000Z

385

Avalanche buildup time of an InP/InGaAsP/InGaAs APD at high gain  

SciTech Connect (OSTI)

Under a high-gain operating condition, the presence of a multiplication process in the InGaAs(P) regions of an InP/InGaAsP/InGaAs avalanche photodiode having a structure of separated absorption and multiplication regions (SAM-APD) could lead to significant enhancement of the avalanche buildup time. As a result, the bandwidth of the device could be reduced considerably. The dependence of the avalanche multiplication factor and the intrinsic response time on the reverse bias voltage, the heterointerface field, the doping concentrations, and the width of the InP layer are examined in detail for the case in which hole injection is assumed. It is shown, for example, that for a fixed value of doping concentrations, the reduction of the excess noise factor and the enhancement of the gain-bandwidth product of the device can be made at the same time by a proper increase of the width of the InP layer.

Hsieh, H.C.; Sargeant, W. (Iowa State Univ. of Science and Technology, Ames, IA (USA). Dept. of Electrical Engineering)

1989-09-01T23:59:59.000Z

386

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

387

Heterobimetallic complexes of gold and mercury. Syntheses and characterizations of Hg sup II (CH sub 2 P(S)Ph sub 2 ) sub 2 (Au sup I Cl) sub 2 and Hg sup II Au sup I (CH sub 2 P(S)Ph sub 2 ) sub 2 Au sup III Cl sub 4  

SciTech Connect (OSTI)

The trinuclear compound Hg{sup II}(CH{sub 2}P(S)Ph{sub 2}){sub 2}(Au{sup I}Cl){sub 2} (2) was synthesized by the reaction of Hg{sup II}(CH{sub 2}P(S)Ph{sub 2}){sub 2} (1) with 2 equiv of Au(THT)Cl (THT = tetrahydrothiophene) in a CH{sub 2}Cl{sub 2} solution. Oxidation of 2 by 1 equiv of C{sub 6}H{sub 5}ICl{sub 2} yielded the mixed-valence trinuclear compound Hg{sup II}Au{sup I}(CH{sub 2}P(S)Ph{sub 2}){sub 2}Au{sup III}Cl{sub 4} (3). The crystal structures of 2 and 3 were determined by single-crystal X-ray diffraction analyses. 2 and 3 have one-dimensional chain structures in the solid. Crystal data: 2, C{sub 26}H{sub 24}HgAu{sub 2}Cl{sub 2}S{sub 2}P{sub 2}{center dot}{sup 1}/{sub 2}C{sub 5}H{sub 12}, space group P{bar 1}, a = 11.930 (4) {angstrom}, b = 13.452 (4) {angstrom}, c = 10.516 (4) {angstrom}, {alpha} = 108.44 (2){degree}, {beta} = 90.61 (3){degree}, {gamma} = 81.06 (2){degree}, V = 1580.1 (8) {angstrom}{sup 3}, Z = 2, R = 0.0432 and R{sub w} = 0.0489 for refinement of 154 least-squares parameters with 2,744 reflections (F{sub {degree}}{sup 2} {ge} 3{sigma}(F{sub {degree}}{sup 2})); 3, C{sub 26}H{sub 24}HgAu{sub 2}Cl{sub 4}S{sub 2}P{sub 2}{center dot}CH{sub 2}Cl{sub 2}, space group P{bar 1}, a = 10.199 (6) {angstrom}, b = 12.340 (3) {angstrom}, c = 15.064 (4) {angstrom}, {alpha} = 74.17 (2){degree}, {beta} = 82.76 (3){degree}, V = 1,799 (1) {angstrom}{sup 3}, Z = 2, R = 0.0505 and R{sub w} = 0.0501 for refinement of 178 least-squares parameters with 1,680 reflections (F{sub 0}{sup 2} {ge} 3{sigma}(F{sub 0}{sup 2})).

Wang, Suning; Fackler, J.P. Jr. (Texas A M Univ., College Station (USA))

1990-01-01T23:59:59.000Z

388

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

389

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 42, NO. 4, APRIL 2006 397 Design and Performance of an InGaAsInP  

E-Print Network [OSTI]

, focusing on the effect of the critical InGaAsP grading layer between the narrow-gap InGaAs absorption layer

Buller, Gerald S.

390

Origin of InGaN/GaN light-emitting diode efficiency improvements using tunnel-junction-cascaded active regions  

SciTech Connect (OSTI)

This Letter investigates the efficiency enhancement achieved by tunnel junction insertion into the InGaN/GaN multi-quantum well (MQW) active region of blue light emitting diodes (LEDs). The peak quantum efficiency of such LED exceeds 100%, but the maximum wall-plug efficiency (WPE) hardly changes. However, due to the increased bias, the WPE peaks at much higher input power, i.e., the WPE droop is significantly delayed, and the output power is strongly enhanced. The main physical reason for this improvement lies in the non-uniform vertical carrier distribution typically observed within InGaN MQWs.

Piprek, Joachim, E-mail: piprek@nusod.org [NUSOD Institute LLC, P.O. Box 7204, Newark, Delaware 19714 (United States)

2014-02-03T23:59:59.000Z

391

Enhancing the Light Extraction of InGaN Light-Emitting Diodes by Patterning the Dicing Streets  

Science Journals Connector (OSTI)

Patterning the dicing streets technology was used to define the high extraction efficiency region of InGaN-GaN multiple-quantum-well light-emitting diodes (LEDs). The external quantum...

Lin, Hung Cheng; Tseng, Yen Chun; Chyi, Jen Inn; Lee, Chia Ming

392

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.

393

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

E-Print Network [OSTI]

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

394

Analyzing the Performance of a Multiobjective GA-P Algorithm for Learning Fuzzy Queries in  

E-Print Network [OSTI]

Analyzing the Performance of a Multiobjective GA-P Algorithm for Learning Fuzzy Queries in a Machine Learning Environment Oscar Cord´on1 , Enrique Herrera-Viedma1 , Mar´ia Luque1 , F´elix de Moya2- tionary algorithms (EAs) [1], such as genetic algorithm-programming (GA-P) [11] or simulated annealing

Fernandez, Thomas

395

Modeling of InAs/GaAs Quantum Dot Solar Cells  

Science Journals Connector (OSTI)

This paper reports electrical characteristics of an intermediate band p-i-n GaAs solar cell with InAs quantum dots embedded in the intrinsic region using Synopsis TCAD simulation tools. Up to five layers of quantum dots have been taken into consideration ... Keywords: Quantum dots, Intermediate band, InAs, GaAs, Solar Cells, TCAD

Ayman Rizk; Kazi Islam; Ammar Nayfeh

2013-11-01T23:59:59.000Z

396

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

E-Print Network [OSTI]

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

Ozbay, Ekmel

397

Ultralow noise midwave infrared InAsGaSb strain layer superlattice avalanche photodiode  

E-Print Network [OSTI]

Ultralow noise midwave infrared InAs­GaSb strain layer superlattice avalanche photodiode InAs­GaSb strain layer superlattice p+ -n- -n homojunction avalanche photodiodes APDs grown by solid characteristics. © 2007 American Institute of Physics. DOI: 10.1063/1.2817608 Photodiodes operating in the eye

Krishna, Sanjay

398

14 MHz rate photon counting with room temperature InGaAs/InP avalanche photodiodes  

E-Print Network [OSTI]

14 MHz rate photon counting with room temperature InGaAs/InP avalanche photodiodes PAUL L. VOSS based on InGaAs/InP avalanche photodiodes for use at 1.55 mm wavelength. Operation at room temperature at the above wavelengths for conventional high light-level measurements with PIN or ava- lanche photodiodes

Köprülü, Kahraman Güçlü

399

Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells  

E-Print Network [OSTI]

Diffusion of indium and gallium in Cu(In,Ga)Se2 thin film solar cells O. Lundberga,*, J. Lua , A. Rockettb , M. Edoffa , L. Stolta a A°ngstro¨m Solar Center, Uppsala University, P.O. Box 534, SE-751 21 Abstract The diffusion of indium and gallium in polycrystalline thin film Cu(In,Ga)Se2 layers has been

Rockett, Angus

400

Resonant Raman scattering in an InAs/GaAs monolayer structure  

E-Print Network [OSTI]

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

Nabben, Reinhard

Note: This page contains sample records for the topic "hg cn 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

Electro-optic imagery of high-voltage GaAs photoconductive switches  

SciTech Connect (OSTI)

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

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

1995-01-01T23:59:59.000Z

402

Variation of lattice constant and cluster formation in GaAsBi  

SciTech Connect (OSTI)

We investigate the structural properties of GaAsBi layers grown by molecular beam epitaxy on GaAs at substrate temperatures between 220–315 °C. Irrespective of the growth temperature, the structures exhibited similar Bi compositions, and good overall crystal quality as deduced from X-Ray diffraction measurements. After thermal annealing at temperatures as low as 500 °C, the GaAsBi layers grown at the lowest temperatures exhibited a significant reduction of the lattice constant. The lattice variation was significantly larger for Bi-containing samples than for Bi-free low-temperature GaAs samples grown as a reference. Rutherford backscattering spectrometry gave no evidence of Bi diffusing out of the layer during annealing. However, dark-field and Z-contrast transmission electron microscopy analyses revealed the formation of GaAsBi clusters with a Bi content higher than in the surrounding matrix, as well as the presence of metallic As clusters. The apparent reduction of the lattice constant can be explained by a two-fold process: the diffusion of the excess As incorporated within As{sub Ga} antisites to As clusters, and the reduction of the Bi content in the GaAs matrix due to diffusion of Bi to GaAsBi clusters. Diffusion of both As and Bi are believed to be assisted by the native point defects, which are present in the low-temperature as-grown material.

Puustinen, J.; Schramm, A.; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland)] [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FI-33101 Tampere (Finland); Wu, M.; Luna, E. [Paul-Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)] [Paul-Drude Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany); Laukkanen, P. [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)] [Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Laitinen, M.; Sajavaara, T. [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)] [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä (Finland)

2013-12-28T23:59:59.000Z

403

ORIGINAL ARTICLE Highly efficient GaAs solar cells by limiting light emission  

E-Print Network [OSTI]

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

Atwater, Harry

404

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

E-Print Network [OSTI]

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

Atwater, Harry

405

Calculated spin polarization of field-assisted GaAs electron source  

Science Journals Connector (OSTI)

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

B. Yang; V. Guidi; L. Tecchio

1993-02-01T23:59:59.000Z

406

Coupling of nitrogen-vacancy centers in diamond to a GaP waveguide  

E-Print Network [OSTI]

The optical coupling of guided modes in a GaP waveguide to nitrogen-vacancy (NV) centers in diamond is demonstrated. The electric field penetration into diamond and the loss of the guided mode are measured. The results indicate that the GaP-diamond system could be useful for realizing coupled microcavity-NV devices for quantum information processing in diamond.

K. -M. C. Fu; C. Santori; P. E. Barclay; I. Aharonovich; S. Prawer; N. Meyer; A. M. Holm; R. G. Beausoleil

2008-11-03T23:59:59.000Z

407

Inductively Coupled Plasma Etching in ICl- and IBr-Based Chemistries: Part II. InP, InSb, InGaP and InGaAs  

SciTech Connect (OSTI)

A parametric study of Inductively Coupled Plasma etching of InP, InSb, InGaP and InGaAs has been carried out in IC1/Ar and IBr/Ar chemistries. Etch rates in excess of 3.1 prrdmin for InP, 3.6 prnh-nin for InSb, 2.3 pm/min for InGaP and 2.2 ~rrdmin for InGaAs were obtained in IBr/Ar plasmas. The ICP etching of In-based materials showed a general tendency: the etch rates increased substantially with increasing the ICP source power and rf chuck power in both chemistries, while they decreased with increasing chamber pressure. The IBr/Ar chemistry typically showed higher etch rates than IC1/Ar, but the etched surface mophologies were fairly poor for both chemistries.

Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Hobson, W.S.; Jung, K.B.; Lambers, E.S.; Pearton, S.J.; Shul, R.J.

1998-11-23T23:59:59.000Z

408

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

SciTech Connect (OSTI)

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

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

2013-04-21T23:59:59.000Z

409

Low-temperature magnetization of (Ga,Mn) As semiconductors  

E-Print Network [OSTI]

der Laan,8 C. T. Foxon,2 and B. L. Gallagher2 1Institute of Physics ASCR, Cukrovarnick? 10, 162 53 Praha 6, Czech Republic 2School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom 3Institute of Physics ASCR, Na... is organized as follows. In Sec. II we identify the key physical considerations related to ground-state mag- netization of #1;Ga,Mn#2;As ferromagnets by focusing first on a single Mn#1;d5+hole#2; complex and approximating the total magnetization...

Jungwirth, T.; Masek, J.; Wang, KY; Edmonds, KW; Sawicki, M.; Polini, M.; Sinova, Jairo; MacDonald, AH; Campion, RP; Zhao, LX; Farley, NRS; Johal, TK; van der Laan, G.; Foxon, CT; Gallagher, BL.

2006-01-01T23:59:59.000Z

410

Theory of weak localization in ferromagnetic (Ga,Mn)As  

E-Print Network [OSTI]

&M University, College Station, Texas 77843-4242, USA 3Institute of Physics, ASCR, v.v.i., Cukrovarnicka 10, 162 53 Praha 6, Czech Republic 4School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom #1;Received 27 November.... Unlike earlier theoretical work15,16 which ad- dressed quantum interference in ferromagnets, we focus our study on a four-band model which is directly relevant to the valence bands of #1;Ga,Mn#2;As. We demonstrate that the quan- tum interference...

Garate, Ion; Sinova, Jairo; Jungwirth, T.; MacDonald, A. H.

2009-01-01T23:59:59.000Z

411

Magnetization relaxation in (Ga,Mn)As ferromagnetic semiconductors  

E-Print Network [OSTI]

- Magnetization relaxation in ?Ga,M Jairo Sinova,1 T. Jungwirth,2,3 X. Liu,4 Y. Sasaki,4 J. K 1Department of Physics, Texas A&M Universit 2Institute of Physics ASCR, Cukrovarnick 3Department of Physics, University of Texa 4Department of Physics, University... is currently the focus of a considerable experimental16 and theoretical17 research. Spin-transfer switching has not yet been demonstrated in all-semiconductor systems, but the effect promises to have a richer phenomenology in this case because...

Sinova, Jairo; Jungwirth, T.; Liu, X.; Sasaki, Y.; Furdyna, JK; Atkinson, WA; MacDonald, AH.

2004-01-01T23:59:59.000Z

412

Quantum effects in electron beam pumped GaAs  

SciTech Connect (OSTI)

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

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

2013-08-19T23:59:59.000Z

413

Exciton front propagation in photoexcited GaAs quantum wells  

Science Journals Connector (OSTI)

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

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

2010-03-16T23:59:59.000Z

414

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

E-Print Network [OSTI]

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

Li, Xiuling

415

Determination of piezoelectric fields in strained GaInN quantum wells using the quantum-confined Stark effect  

E-Print Network [OSTI]

fields on optical prop- erties in the cases of GaInAs/GaAs QWs2 and CdS/CdSe superlattices4 on GaAs 111 MOVPE . The total un- doped region sandwiched by n and p layers is 51 nm. The carrier concentrations

Wetzel, Christian M.

416

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

E-Print Network [OSTI]

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

Atwater, Harry

417

Intrinsic vacancy induced nanoscale wire structure in heteroepitaxial Ga2Se3/Si(001) Taisuke Ohta,1,  

E-Print Network [OSTI]

Intrinsic vacancy induced nanoscale wire structure in heteroepitaxial Ga2Se3/Si(001) Taisuke Ohta,1-blende structure of -Ga2Se3, which contains ordered 110 arrays of Ga vacancies. These ordered vacancy lines structural vacancies of semiconducting chalcogenides lead to numerous interesting structural, electronic

Olmstead, Marjorie

418

Identification of the Parasitic Chemical Reactions during AlGaN OMVPE  

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

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

419

Enhanced photoelectrochemical responses of ZnO films through Ga and N codoping  

SciTech Connect (OSTI)

We report on the crystallinity and photoelectrochemical (PEC) response of ZnO thin films codoped by Ga and N. The ZnO:(Ga,N) thin films were deposited by cosputtering at room temperature and followed by postannealing at 500 deg. C in air for 2 h. We found that ZnO:(Ga,N) thin films exhibited significantly enhanced crystallinity compared to ZnO doped solely with N at the same growth conditions. Furthermore, ZnO:(Ga,N) thin films exhibited enhanced N incorporation over ZnO doped solely with N at high temperatures. As a result, ZnO:(Ga,N) thin films achieved dramatically improved PEC response, compared to ZnO thin films doped solely with N at any conditions. Our results suggest a general way to improve PEC response for wide-band-gap oxides.

Ahn, Kwang-Soon; Yan, Yanfa; Shet, Sudhakar; Deutsch, Todd; Turner, John; Al-Jassim, Mowafak [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)

2007-12-03T23:59:59.000Z

420

Infrared spectroscopy of amorphous hydrogenated GaAs: Evidence for H bridges  

Science Journals Connector (OSTI)

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

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

1982-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

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.

422

Two-fermion–four-boson description of Hg198 within the U?(6/12)?U?(6/4) extended nuclear structure supersymmetry  

Science Journals Connector (OSTI)

Using the U?(6/12)?U?(6/4) extended supersymmetry, we constructed the energy spectrum and electromagnetic transition properties of the supermultiplet member Hg198 with two proton fermions coupled to a neutron boson core. Consistency between the supersymmetric interacting boson fermion fermion approximation (IBFFA) description and the F-spin symmetric interacting boson approximation (IBA-2) description is shown for this two-fermion–N-boson multiplet member. The data of a ?? angular correlation experiment using the HORUS cube ?-ray spectrometer—determining new multipole mixing ratios, level spins, ? transitions, and energy states—shows quite a good agreement, also for the low-energy part of the spectrum, when comparing theoretical predictions and experimental data. This is contrary to the usual assumption that a two-fermion–N-boson constellation should describe just the excited two-quasiparticle states.

C. Bernards; S. Heinze; J. Jolie; C. Fransen; A. Linnemann; D. Radeck

2009-05-11T23:59:59.000Z

423

High-lying bound Rydberg states of excited Hg(6s6p {sup 3}P{sub 1}) atoms from two-color resonance ionization mass spectroscopy  

SciTech Connect (OSTI)

Mercury isotopes are investigated with two-color resonance ionization mass spectroscopy (RIMS). Isotope shifts, hyperfine structure splittings, and the lifetime of the intermediate 6s6p {sup 3}P{sub 1} state are determined by RIMS. Ion yields at the threshold region in various static electric fields are measured in order to determine an extrapolated ionization energy value at zero field strength. New energy values for high-lying bound 6s nd {sup 3}D (21Hg isotopes are found under field-free conditions and with delayed, pulsed electric field ionization. To the author's knowledge this is the first time that isotopic effects on the ionization energy are deduced from the convergence limit of the Rydberg series.

Bisling, Peter; Dederichs, Jan; Neidhart, Bernd; Weitkamp, Claus [GKSS-Forschungszentrum Geesthacht GmbH, Postfach 11 60, D-21494 Geesthacht (Germany)

1998-12-16T23:59:59.000Z

424

Dynamic nuclear polarization and Hanle effect in (In,Ga)As/GaAs quantum dots. Role of nuclear spin fluctuations  

SciTech Connect (OSTI)

The degree of circular polarization of photoluminescence of (In,Ga)As quantum dots as a function of magnetic field applied perpendicular to the optical axis (Hanle effect) is experimentally studied. The measurements have been performed at various regimes of the optical excitation modulation. The analysis of experimental data has been performed in the framework of a vector model of regular nuclear spin polarization and its fluctuations. The analysis allowed us to evaluate the magnitude of nuclear polarization and its dynamics at the experimental conditions used.

Gerlovin, I. Ya. [Spin Optics Laboratory, Saint Petersburg State University, Petrodvorets, 198504 St. Petersburg (Russian Federation); Cherbunin, R. V.; Ignatiev, I. V.; Kuznetsova, M. S.; Verbin, S. Yu. [Spin Optics Laboratory, Saint Petersburg State University, Petrodvorets, 198504 St. Petersburg, Russia and Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund (Germany); Flisinski, K.; Bayer, M. [Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund (Germany); Reuter, D.; Wieck, A. D. [Angewandte Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Yakovlev, D. R. [Experimentelle Physik 2, Technische Universität Dortmund, D-44221 Dortmund, Germany and A. F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation)

2013-12-04T23:59:59.000Z

425

Optical resonance modes in GaN pyramid microcavities  

SciTech Connect (OSTI)

An array of GaN hexagonal pyramids with a side length of 8.0 {mu}m was fabricated by selective epitaxial overgrowth. These microsized pyramids are highly efficient microcavities. Three types of optical resonance modes with mode spacings of 10, 5.0, and 6.0 {Angstrom} were observed when a single pyramid was pumped optically by an intense ultraviolet laser beam. An optical ray tracing method has been developed for calculating the optical resonance modes inside the pyramid microcavities. It was shown that a single pyramidal cavity can support several different types of optical resonance modes. The calculated mode spacing agrees very well with the observations. The uniqueness and advantages of this class of hexagonal pyramidal microcavities over the other microcavities are discussed. The implications of our finding on the future GaN microcavity light emitters including micro-light-emitting diodes, microcavity lasers, and vertical-cavity-surface emitting lasers are also discussed. {copyright} {ital 1999 American Institute of Physics.}

Jiang, H.X.; Lin, J.Y.; Zeng, K.C. [Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States)] [Department of Physics, Kansas State University, Manhattan, Kansas 66506-2601 (United States); Yang, W. [Honeywell Technology Center, Plymouth, Minnesota 55441 (United States)] [Honeywell Technology Center, Plymouth, Minnesota 55441 (United States)

1999-08-01T23:59:59.000Z

426

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

427

Effect of Spin-Crossover-Induced Pore Contraction on CO{sub 2}-Host Interactions in the Porous Coordination Polymers [Fe(pyrazine)M(CN){sub 4}] (M = Ni, Pt)  

SciTech Connect (OSTI)

Variable-temperature in situ ATR-FTIR spectra are presented for the porous spin-crossover compounds [Fe(pyrazine)- Ni(CN){sub 4}] and [Fe(pyrazine)Pt(CN){sub 4}] under CO{sub 2} pressures of up to 8 bar. Significant shifts in the ?{sub 3} and ?{sub 2} IR absorption bands of adsorbed CO{sub 2} are observed as the host materials undergo transition between low- and high-spin states. Computational models used to determine the packing arrangement of CO{sub 2} within the pore structures show a preferred orientation of one of the adsorbed CO{sub 2} molecules with close O=C=O···H contacts with the pyrazine pillar ligands. The interaction is a consequence of the commensurate distance of the inter-pyrazine separations and the length of the CO{sub 2} molecule, which allows the adsorbed CO{sub 2} to effectively bridge the pyrazine pillars in the structure. The models were used to assign the distinct shifts in the IR absorption bands of the adsorbed CO{sub 2} that arise from changes in the O=C=O···H contacts that strengthen and weaken in correlation with changes in the Fe–N bond lengths as the spin state of Fe changes. The results indicate that spin-crossover compounds can function as a unique type of flexible sorbent in which the pore contractions associated with spin transition can affect the strength of CO{sub 2}–host interactions.

Culp, Jeffrey T.; Chen, De-Li; Liu, Jinchen; Chirdon, Danielle; Kauffman, Kristi; Goodman, Angela; Johnson, J. Karl

2013-02-01T23:59:59.000Z

428

Temperature measurement of an atmospheric pressure arc discharge plasma jet using the diatomic CN (B {sup 2}{sigma}{sup +}-X {sup 2}{sigma}{sup +}, violet system) molecular spectra  

SciTech Connect (OSTI)

The CN (B {sup 2}{sigma}{sup +}-X {sup 2}{sigma}{sup +}) molecular emission spectrum is used to measure both the vibrational and rotational temperatures in atmospheric pressure arc jet discharges. The vibrational and rotational temperature effects on the synthetic diatomic molecular spectra were investigated from the (v{sup '},v{sup ''})=(0,0) band to the (5,5) band. The temperatures obtained from the synthetic spectra compared with the experimental result of a low-frequency arc discharge show a vibrational temperature of (4250-5010) K and a rotational temperature of (3760-3980) K for the input power in the range of (80-280) W. As the (0,0) band is isolated from other vibrational transition bands, determination of the rotational temperature is possible based only on the (0,0) band, which simplifies the temperature measurement. From the result, it was found that the CN molecular spectrum can be used as a thermometer for atmospheric pressure plasmas containing carbon and nitrogen.

Moon, Se Youn; Kim, D. B.; Gweon, B.; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2009-03-01T23:59:59.000Z

429

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

Science Journals Connector (OSTI)

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

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

2007-01-02T23:59:59.000Z

430

Enhanced quality thin film Cu(In,Ga)Se.sub.2 for semiconductor device applications by vapor-phase recrystallization  

DOE Patents [OSTI]

Enhanced quality thin films of Cu.sub.w (In,Ga.sub.y)Se.sub.z for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu.sub.x Se on a substrate to form a large-grain precursor and then converting the excess Cu.sub.x Se to Cu(In,Ga)Se.sub.2 by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga).sub.y Se.sub.z. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300.degree.-600.degree. C., where the Cu(In,Ga)Se.sub.2 remains solid, while the excess Cu.sub.x Se is in a liquid flux. The characteristic of the resulting Cu.sub.w (In,Ga).sub.y Se.sub.z can be controlled by the temperature. Higher temperatures, such as 500.degree.-600.degree. C., result in a nearly stoichiometric Cu(In,Ga)Se.sub.2, whereas lower temperatures, such as 300.degree.-400.degree. C., result in a more Cu-poor compound, such as the Cu.sub.z (In,Ga).sub.4 Se.sub.7 phase.

Tuttle, John R. (Denver, CO); Contreras, Miguel A. (Golden, CO); Noufi, Rommel (Golden, CO); Albin, David S. (Denver, CO)

1994-01-01T23:59:59.000Z

431

Enhanced quality thin film Cu(In,Ga)Se[sub 2] for semiconductor device applications by vapor-phase recrystallization  

DOE Patents [OSTI]

Enhanced quality thin films of Cu[sub w](In,Ga[sub y])Se[sub z] for semiconductor device applications are fabricated by initially forming a Cu-rich, phase-separated compound mixture comprising Cu(In,Ga):Cu[sub x]Se on a substrate to form a large-grain precursor and then converting the excess Cu[sub x]Se to Cu(In,Ga)Se[sub 2] by exposing it to an activity of In and/or Ga, either in vapor In and/or Ga form or in solid (In,Ga)[sub y]Se[sub z]. Alternatively, the conversion can be made by sequential deposition of In and/or Ga and Se onto the phase-separated precursor. The conversion process is preferably performed in the temperature range of about 300--600 C, where the Cu(In,Ga)Se[sub 2] remains solid, while the excess Cu[sub x]Se is in a liquid flux. The characteristic of the resulting Cu[sub w](In,Ga)[sub y]Se[sub z] can be controlled by the temperature. Higher temperatures, such as 500--600 C, result in a nearly stoichiometric Cu(In,Ga)Se[sub 2], whereas lower temperatures, such as 300--400 C, result in a more Cu-poor compound, such as the Cu[sub z](In,Ga)[sub 4]Se[sub 7] phase. 7 figs.

Tuttle, J.R.; Contreras, M.A.; Noufi, R.; Albin, D.S.

1994-10-18T23:59:59.000Z

432

Beyer H.-G., Czeplak G., Terzenbach U., Wald L., 1997. Assessment of the method used to construct clearness index maps for the new european solar radiation atlas (ESRA). Solar Energy, 61, 6, 389-397.  

E-Print Network [OSTI]

clearness index maps for the new european solar radiation atlas (ESRA). Solar Energy, 61, 6, 389 period 1981-1990, the setup of a toolbox to derive the radiation parameters of relevance for solar energy, published in "Solar Energy 61, 6 (1997) 389-397" #12;Beyer H.-G., Czeplak G., Terzenbach U., Wald L., 1997

Paris-Sud XI, Université de

433

Prof. Dr. Uwe Holtz Universitt Bonn Am Hofgarten 15D -53113 Bonn UHoltz@aol.com www.uni-bonn.de/~uholtz1 OECD (Hg.): DAC Peer Review Germany, Paris 2006.4  

E-Print Network [OSTI]

.uni-bonn.de/~uholtz1 6.4.072 3 OECD (Hg.): DAC Peer Review Germany, Paris 2006.4 (www.oecd.org/dataoecd/54 of poorer countries but need for greater strategic selectivity8 9 Germany has never stated a preference in favor of specific groups of countries. Germany admits10 that poorest countries need donors' full support

Franz, Sven Oliver

434

Many-body effects on optical gain in GaAsPN/GaPN quantum well lasers for silicon integration  

SciTech Connect (OSTI)

Many-body effects on the optical gain in GaAsPN/GaP QW structures were investigated by using the multiband effective-mass theory and the non-Markovian gain model with many-body effects. The free-carrier model shows that the optical gain peak slightly increases with increasing N composition. In addition, the QW structure with a larger As composition shows a larger optical gain than that with a smaller As composition. On the other hand, in the case of the many-body model, the optical gain peak decreases with increasing N composition. Also, the QW structure with a smaller As composition is observed to have a larger optical gain than that with a larger As composition. This can be explained by the fact that the QW structure with a smaller As or N composition shows a larger Coulomb enhancement effect than that with a larger As or N composition. This means that it is important to consider the many-body effect in obtaining guidelines for device design issues.

Park, Seoung-Hwan, E-mail: shpark@cu.ac.kr [Department of Electronics Engineering, Catholic University of Daegu, Hayang, Kyeongbuk 712-702 (Korea, Republic of)

2014-02-14T23:59:59.000Z

435

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

SciTech Connect (OSTI)

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

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

1987-10-01T23:59:59.000Z

436

Lattice dynamics of GaN: Effects of 3d electrons  

Science Journals Connector (OSTI)

We perform first-principles calculations of structural, dielectric, and lattice-dynamical properties of cubic GaN. The equilibrium structure is obtained using the plane-wave pseudopotential approach within the density-functional theory and local-density approximation. The dielectric and vibrational properties are computed within the density-functional perturbation theory. The effect of the Ga 3d electrons is treated by taking into account the nonlinear core corrections for the exchange and correlation energy. The importance of 3d electrons for the bonding strength is determined, and their influence on the dielectric and dynamical properties of GaN is analyzed and discussed.

K. Karch; F. Bechstedt; T. Pletl

1997-08-15T23:59:59.000Z

437

Atomic geometry of the 2×2 GaP(111) surface  

Science Journals Connector (OSTI)

Integral and fractional order beam low-energy electron-diffraction intensity-voltage (I-V) data have been taken on a bombardment-annealed GaP(111)-(2×2) surface. We have compared these data with calculated I-V curves using a dynamical multiple scattering theory and found very good agreement for the following model: One out of every four Ga surface atoms is missing and the surface Ga-P bilayer is almost coplanar. Surface and deeper layer atoms undergo vertical and lateral displacements from bulk positions. Similar results in other systems suggest that the vacancy model applies on the (111) face of many compound semiconductors.

G. Xu; W. Y. Hu; M. W. Puga; S. Y. Tong; J. L. Yeh; S. R. Wang; B. W. Lee

1985-12-15T23:59:59.000Z

438

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"

439

Growth and optical characterization of multilayers of InGaN quantum dots  

E-Print Network [OSTI]

GaN quantum dots Article Type: Research Paper Section/Category: General subjects Keywords: B2. InGaN quantum dots; A1. Photoluminescence; B1. Nitrides; A3. Metal-organic vapour phase epitaxy Corresponding Author: Dr Tongtong Zhu, Ph... , Cambridge, CB2 3QZ, UK Dr Tongtong Zhu Tel: +44 1223 334368 Fax: +44 1223 334437 E-mail: tz234@cam.ac.uk 9 Sep 2011 Dear Editor, Title: Growth and optical characterization of multilayers of InGaN quantum dots Authors: Tongtong Zhu, Haitham A...

Zhu, Tontong; El-Ella, Haitham; Reid, Benjamin; Holmes, Mark; Taylor, Robert; Kappers, Menno; Oliver, Rachel

2012-01-01T23:59:59.000Z

440

Low threshold for optical damage in AlGaN epilayers and heterostructures  

SciTech Connect (OSTI)

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

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

2013-11-28T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

Ferromagnetism of GaMnAs studied by polarized neutron reflectometry  

Science Journals Connector (OSTI)

Polarized neutron reflectometry has been used to investigate details of spin ordering in ferromagnetic (FM) GaMnAs/GaAs superlattices. The reflectivity spectra measured below the Curie temperature reveal additional magnetic contributions to the structural superlattice Bragg peaks, clearly indicating the existence of FM interlayer correlations. Closer investigation of the magnetic reflectivity maxima using a full polarization analysis provides direct evidence that the FM order in the GaMnAs layers is truly long range. Moreover, as shown by the data, the system exhibits a strong tendency of forming a single-domain FM arrangement, even when cooled through TC in zero external field.

H. K?pa; J. Kutner-Pielaszek; A. Twardowski; C. F. Majkrzak; J. Sadowski; T. Story; T. M. Giebultowicz

2001-09-05T23:59:59.000Z

442

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

SciTech Connect (OSTI)

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

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

2013-09-09T23:59:59.000Z

443

Formation energy of excess arsenic atoms in n-type GaAs  

Science Journals Connector (OSTI)

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

Jun-ichi Nishizawa; Yutaka Oyama; Kazushi Dezaki

1990-11-12T23:59:59.000Z

444

Development of a Multifilament PIT V3Ga Conductor for Fusion Applications  

SciTech Connect (OSTI)

Previous studies on V{sub 3}Ga assert its suitability for use in proposed fusion reactors. V{sub 3}Ga may outperform Nb{sub 3}Sn in a fusion reactor environment based on its relatively flat critical-current profile in the 15 T-20 T range, resilience to applied strain, and reduced risk of induced radioactivity. A multifilament powder-in-tube V{sub 3}Ga conductor was designed, fabricated and tested with a focus on evaluating critical current versus applied field and applied strain performance, wire drawing difficulties, heat-treatment optimization, and overall feasibility of the concept.

Distin, J.S.; Ghosh, A.; Motowidlo, L.R.; Lee, P.J.; Larbalestier, D.C.; Lu, X.F.; Cheggour, N.; Stauffer, T.C.; Goodrich, L.F.

2011-08-03T23:59:59.000Z

445

Intersubband transitions in In{sub x}Ga{sub 1?x}N/In{sub y}Ga{sub 1?y}N/GaN staggered quantum wells  

SciTech Connect (OSTI)

Intersubband transition energies and absorption lineshape in staggered InGaN/GaN quantum wells surrounded by GaN barriers are computed as functions of structural parameters such as well width, In concentrations, and the doping level in the well. Schrödinger and Poisson equations are solved self-consistently by taking the free and bound surface charge concentrations into account. Many-body effects, namely, depolarization and excitonic shifts are also included in the calculations. Results for transition energies, oscillator strength, and the absorption lineshape up to nonlinear regime are represented as functions of the parameters mentioned. The well width (total and constituent layers separately) and In concentration dependence of the built-in electric field are exploited to tune the intersubband transition energies.

Y?ld?r?m, Hasan, E-mail: hasanyildirim@karabuk.edu.tr [Department of Occupational Health and Safety, School of Health, Karabuk University, Karabuk 78050 (Turkey); Aslan, Bulent, E-mail: bulentaslan@anadolu.edu.tr [Department of Physics, Faculty of Science, Anadolu University Yunus Emre Campus, Eskisehir 26470 (Turkey)

2014-04-28T23:59:59.000Z

446

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

Science Journals Connector (OSTI)

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

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

2003-07-10T23:59:59.000Z

447

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

SciTech Connect (OSTI)

We discuss recent developments in III-V multijunction solar cells, focusing on adding a fourth junction to the Ga0.5In0.5P/GaAs/Ga0.75In0.25As inverted three-junction cell. This cell, grown inverted on GaAs so that the lattice-mismatched Ga0.75In0.25As 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 GaxIn1-xAs 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 GaxIn1-xAs 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.

2006-05-01T23:59:59.000Z

448

Carrier cooling and exciton formation in GaSe  

Science Journals Connector (OSTI)

The initial cooling of hot carriers and the subsequent exciton formation in GaSe are studied by time-resolved photoluminescence (PL) using femtosecond up-conversion techniques. From the time-resolved PL spectra of this layered III-VI semiconductor two different energy relaxation channels are derived. After an initial subpicosecond cooling due to Fröhlich-type interaction of carriers with longitudinal optical E?(22) phonons a slower regime follows, which is dominated by deformation potential interaction with the nonpolar optical A1?(12) phonons. The coupling constant for nonpolar optical phonon scattering is derived. The subsequent formation of excitons is studied at different carrier densities and detection energies. A cross section for the free-exciton formation is determined based on a rate equation model.

S. Nüsse; P. Haring Bolivar; H. Kurz; V. Klimov; F. Levy

1997-08-15T23:59:59.000Z

449

Dimensionality of InGaAs nonlinear optical response  

SciTech Connect (OSTI)

In this thesis the ultrafast optical properties of a series of InGaAs samples ranging from the two to the three dimensional limit are discussed. An optical system producing 150 fs continuum centered at 1.5 microns was built. Using this system, ultrafast pump-probe and four wave mixing experiments were performed. Carrier thermalization measurements reveal that screening of the Coulomb interaction is relatively unaffected by confinement, while Pauli blocking nonlinearities at the band edge are approximately twice as strong in two dimensions as in three. Carrier cooling via phonon emission is influenced by confinement due both to the change in electron distribution function and the reduction in electron phonon coupling. Purely coherent band edge effects, as measured by the AC Stark effect and four wave mixing, are found to be dominated by the changes in excitonic structure which take place with confinement.

Bolton, S.R. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

1995-07-01T23:59:59.000Z

450

Temperature dependence of optical transitions in AlGaAs  

Science Journals Connector (OSTI)

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

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

2001-01-01T23:59:59.000Z

451

Strain-driven transition from stepped interfaces to regularly spaced macrosteps in (GaIn)As/Ga(PAs) symmetrically strained superlattices  

Science Journals Connector (OSTI)

We investigate the morphological transition from a steplike interface modulation to a highly periodic lateral thickness modulation that occurs on symmetrically strained (GaIn)As/GaAs/Ga(PAs)/GaAs superlattices grown by metal-organic vapor phase epitaxy on miscut (001)GaAs substrate. The combination of x-ray reciprocal-space mapping, around the (004) as well as the (200) and (020) reciprocal-lattice points, and transmission electron microscopy allowed us to monitor and analyze accurately the structural periodicities and ordering of heterointerfaces and to relate them to the elastic strain field. The laterally ordered macrosteps on the growth surface are investigated and discussed as a function of the strain misfit between epitaxial layer and substrate. Within this purpose, the complementary information obtained by grazing-incidence x-ray diffraction, by looking at different reciprocal-lattice points, is discussed in relationship to the effects of strain and morphological modulation of the interfaces in the process of macrostep formation.

C. Giannini; T. Baumbach; D. Lübbert; R. Felici; L. Tapfer; T. Marschner; W. Stolz; N. Y. Jin-Phillipp; F. Phillipp

2000-01-15T23:59:59.000Z

452

Development of 1.25 eV InGaAsN for triple junction solar cells  

SciTech Connect (OSTI)

Development of next generation high efficiency space monolithic multifunction solar cells will involve the development of new materials lattice matched to GaAs. One promising material is 1.05 eV InGaAsN, to be used in a four junction GaInP{sub 2}/GaAs/InGaAsN/Ge device. The AMO theoretical efficiency of such a device is 38--42%. Development of the 1.05 eV InGaAsN material for photovoltaic applications, however, has been difficult. Low electron mobilities and short minority carrier lifetimes have resulted in short minority carrier diffusion lengths. Increasing the nitrogen incorporation decreases the minority carrier lifetime. The authors are looking at a more modest proposal, developing 1.25 eV InGaAsN for a triple junction GaInP{sub 2}/InGaAsN/Ge device. The AMO theoretical efficiency of this device is 30--34%. Less nitrogen and indium are required to lower the bandgap to 1.25 eV and maintain the lattice matching to GaAs. Hence, development and optimization of the 1.25 eV material for photovoltaic devices should be easier than that for the 1.05 eV material.

LI,N.Y.; SHARPS,P.R.; HILLS,J.S.; HOU,H.; CHANG,PING-CHIH; BACA,ALBERT G.

2000-05-16T23:59:59.000Z

453

Dry patterning of InGaN and InAlN  

Science Journals Connector (OSTI)

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

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

1994-01-01T23:59:59.000Z

454

Watching GaN Nanowires Grow Eric A. Stach,*, Peter J. Pauzauskie, Tevye Kuykendall,  

E-Print Network [OSTI]

Vision, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Uni and experimentally demonstrated that congruent sublimation of GaN is possible, which yields diatomic or polymeric

Yang, Peidong

455

Efficiency enhancement in GaAs solar cells using self-assembled microspheres  

Science Journals Connector (OSTI)

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

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

2009-01-01T23:59:59.000Z

456

In situ studies of the effect of silicon on GaN growth modes.  

SciTech Connect (OSTI)

We present real-time X-ray scattering studies of the influence of silicon on the homoepitaxial growth mode of GaN grown by metal-organic vapor-phase epitaxy. Both annealing of Si-doped GaN and surface dosing of GaN with disilane are shown to change the mode of subsequent growth from step-flow to layer-by-layer. By comparing the growth behavior induced by doped layers which have been annealed to that induced by surface dosing, we extract an approximate diffusion coefficient for Si in GaN of 3.5 x 10{sup -18} cm{sup 2}/s at 810{sup o}C.

Munkholm, A.; Stephenson, G. B.; Eastman, J. A.; Auciello, O.; Murty, M. V. R.; Thompson, C.; Fini, P.; Speck, J. S.; DenBaars, S. P.; Northern Illinois Univ.; Univ. of California at Santa Barbara

2000-12-01T23:59:59.000Z

457

Price of Elba Island, GA Natural Gas LNG Imports from Equatorial...  

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

Equatorial Guinea (Dollars per Thousand Cubic Feet) Price of Elba Island, GA Natural Gas LNG Imports from Equatorial Guinea (Dollars per Thousand Cubic Feet) Decade Year-0 Year-1...

458

Price of Elba Island, GA Natural Gas LNG Imports from Nigeria...  

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

Nigeria (Nominal Dollars per Thousand Cubic Feet) Price of Elba Island, GA Natural Gas LNG Imports from Nigeria (Nominal Dollars per Thousand Cubic Feet) Decade Year-0 Year-1...

459

Nanoscale Materials for Thin Film Cu(In,Ga)Se2 Solar Cells  

Science Journals Connector (OSTI)

Cu(In,Ga)Se2 solar cells show the highest efficiencies of all thin film technologies. Nano-particulate precursor materials could have the potential to lead this technology to...

Ahlswede, Erik

460

Deeply-scaled GaN high electron mobility transistors for RF applications  

E-Print Network [OSTI]

Due to the unique combination of large critical breakdown field and high electron velocity, GaN-based high electron mobility transistors (HEMTs) have great potential for next generation high power RF amplifiers. The ...

Lee, Dong Seup

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "hg cn 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

A Constraint Handling Strategy for Bit-Array Representation GA in Structural Topology Optimization  

E-Print Network [OSTI]

In this study, an improved bit-array representation method for structural topology optimization using the Genetic Algorithm (GA) is proposed. The issue of representation degeneracy is fully addressed and the importance of ...

Wang, Shengyin

462

Millimeter-wave GaN high electron mobility transistors and their integration with silicon electronics  

E-Print Network [OSTI]

In spite of the great progress in performance achieved during the last few years, GaN high electron mobility transistors (HEMTs) still have several important issues to be solved for millimeter-wave (30 ~ 300 GHz) applications. ...

Chung, Jinwook W. (Jinwook Will)

2011-01-01T23:59:59.000Z

463

Computational Thermodynamics of CoNiGa High Temperature Shape Memory Alloys  

E-Print Network [OSTI]

Shape Memory Alloys (SMAs) are advanced materials with interesting properties such as pseudoelasticity (PE) and the shape memory effect (SME). Recently, the CoNiGa system has emerged as the basis for very promising High Temperature Shape Memory...

Chari, Arpita

2012-10-19T23:59:59.000Z

464

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

SciTech Connect (OSTI)

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

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

2013-12-16T23:59:59.000Z

465

GA CLASSROOM ASSIGNMENT PROCEDURES POST-PUBLICATION REASONS YOU MAY WANT TO CHANGE A CLASSROOM ASSIGNMENT  

E-Print Network [OSTI]

GA CLASSROOM ASSIGNMENT PROCEDURES POST-PUBLICATION REASONS YOU MAY WANT TO CHANGE A CLASSROOM for disabled instructor and/or students PROCEDURES FOR GENERAL ASSIGNMENT CLASSROOM ASSIGNMENTS Requests

Wisconsin at Madison, University of

466

Amorphization Processes in Au Ion Irradiated GaN at 150 - 300...  

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

and small crystalline zones that are randomly oriented. Citation: Jiang W, WJ Weber, LM Wang, and K Sun.2004."Amorphization Processes in Au Ion Irradiated GaN at 150 - 300...

467

Lattice-Mismatched GaInP LED Devices and Methods of Fabricating...  

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

Stories News Events Find More Like This Return to Search Lattice-Mismatched GaInP LED Devices and Methods of Fabricating Same United States Patent Application Publication...

468

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

E-Print Network [OSTI]

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

Bang, Ambjørn Dahle

2014-01-01T23:59:59.000Z

469

Identification of the gallium vacancy-oxygen pair defect in GaN  

SciTech Connect (OSTI)

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

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

2009-10-15T23:59:59.000Z

470

Thermal annealing characteristics of Si and Mg-implanted GaN thin films  

SciTech Connect (OSTI)

In this letter, we report the results of ion implantation of GaN using {sup 28}Si and {sup 24}Mg species. Structural and electrical characterizations of the GaN thin films after thermal annealing show that native defects in the GaN films dominate over implant doping effects. The formation energies of the annealing induced defects are estimated to range from 1.4 to 3.6 eV. A 40 keV 10{sup 14} cm{sup {minus}2} Mg implant results in the decrease of the free-carrier concentration by three orders of magnitude compared to unimplanted GaN up to an annealing temperature of 690{degree}C. Furthermore, we have observed the correlation between these annealing-induced defects to both improved optical and electrical properties. {copyright} {ital 1996 American Institute of Physics.}

Chan, J.S.; Cheung, N.W. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)] [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Schloss, L.; Jones, E.; Wong, W.S.; Newman, N.; Liu, X.; Weber, E.R. [Department of Material Science and Mineral Engineering, University of California, Berkeley, California 64720 (United States)] [Department of Material Science and Mineral Engineering, University of California, Berkeley, California 64720 (United States); Gassman, A.; Rubin, M.D. [Lawrence Berkeley Laboratory, 1 Cyclotron Road, University of California, Berkeley, California 64720 (United States)] [Lawrence Berkeley Laboratory, 1 Cyclotron Road, University of California, Berkeley, California 64720 (United States)

1996-05-01T23:59:59.000Z

471

In-situ ellipsometry: Identification of surface terminations during GaN growth , T. Schmidtling1  

E-Print Network [OSTI]

1 In-situ ellipsometry: Identification of surface terminations during GaN growth C. Cobet1 , T SE, one is not limited to any special bulk or surface symmetry for optical characterisation. In PAMBE

Feenstra, Randall

472

Unambiguous determination of carrier concentration and mobility for InAs/GaSb superlattice photodiode optimization  

SciTech Connect (OSTI)

In this communication we report on electrical properties of nonintentionally doped (nid) type II InAs/GaSb superlattice grown by molecular beam epitaxy. We present a simple technological process which, thanks to the suppression of substrate, allows direct Hall measurement on superlattice structures grown on conductive GaSb substrate. Two samples were used to characterize the transport: one grown on a semi-insulating GaAs substrate and another grown on n-GaSb substrate where a etch stop layer was inserted to remove the conductive substrate. Mobilities and carrier concentrations have been measured as a function of temperature (77-300 K), and compared with capacitance-voltage characteristic at 80 K of a photodiode comprising a similar nid superlattice.

Cervera, C.; Rodriguez, J. B.; Perez, J. P.; Aiet-Kaci, H.; Chaghi, R.; Christol, P. [Institut d'Electronique du Sud (IES), UMR CNRS 5214, Case 067, Universite Montpellier 2, 34095 Montpellier Cedex 05 (France); Konczewicz, L.; Contreras, S. [Groupe d'Etude des Semiconducteurs (GES), UMR CNRS 5650, Case 074, Universite Montpellier 2, 34095 Montpellier Cedex 5 (France)

2009-08-01T23:59:59.000Z

473

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

E-Print Network [OSTI]

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

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

2009-03-01T23:59:59.000Z

474

GaN quantum dot superlattices grown by molecular beam epitaxy at high temperature  

E-Print Network [OSTI]

P-based optoelectronic devices with Si microelectronic devices. This method uses a Au-Ge eutectic alloy as the bonding. The realization of integrafion of GaAs- and InP-based optoelectronic devices with Si microelectronic components

475

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

476

Recombination Lifetime of InxGa1-xAs Alloys Used in Thermophotovoltaic Converters  

SciTech Connect (OSTI)

The family of ternary compounds of composition InxGa1-xAs are of considerable interest for thermophotovoltaic energy converters. The recombination lifetimes of the various compositions are critical to the successful application of these materials as efficient converters. Here we will describe experimental results on the composition. In0.53Ga0.47 that is lattice-matched to InP. We will also describe lifetime results on the compositions In0.68Ga0.32As, with bandgap of 0.60 eV to compositions In0.78Ga0.22As with a bandgap of 0.50 eV. Double heterostructure confinement devices have been made over a range of both n- and p-type doping. These results are preliminary, but the goal is to obtain the radiative and Auger recombination coefficients for the alloys in this composition range.

Ahrenkiel, R. K.; Ellingson, R.; Johnston, S.; Webb, J.; Carapella, J.; Wanlass, M.

1999-02-16T23:59:59.000Z

477

Understanding and development of combined acoustic and magnetic actuation of Ni?MnGa single crystals  

E-Print Network [OSTI]

Ni-Mn-Ga based ferromagnetic shape memory alloys (FSMAs) have emerged as a promising new class of active materials capable of producing a large (several %) magnetic-field-induced strain (MFIS). FSMAs still have several ...

Techapiesancharoenkij, Ratchatee, 1979-

2007-01-01T23:59:59.000Z

478

Frequency Response of Acoustic-Assisted Ni–Mn–Ga Ferromagnetic- Shape-Memory-Alloy Actuator  

E-Print Network [OSTI]

A prototype of Ni–Mn–Ga based ferromagnetic-shape-memory-alloy (FSMA) actuator was designed and built; an acoustic-assist technique was applied to the actuator to enhance its performance. A piezoelectric stack actuator was ...

Techapiesancharoenkij, Ratchatee

479

Effect of buffer layer growth temperature on epitaxial GaN films deposited by magnetron sputtering  

SciTech Connect (OSTI)

Epitaxial GaN films were deposited by reactive sputtering of a GaAs target in 100 % nitrogen at 700 deg. C on ZnO buffer layers grown at different substrate temperatures over sapphire substrates. High resolution X-ray diffraction measurements and the corresponding analysis show that the growth temperature of buffer layers significantly affects the micro-structural parameters of GaN epilayer, such as lateral coherence length, tilt and twist, while the vertical coherence length remains unaffected. The optimum substrate temperature for buffer layer growth has been found to be 300 deg. C. High epitaxial quality GaN film grown on such a buffer layer exhibited micro strain of 1.8x10{sup -4} along with screw and edge type dislocation densities of 7.87x10{sup 9} and 1.16x10{sup 11}, respectively.

Mohanta, P.; Singh, D.; Kumar, R.; Ganguli, T.; Srinivasa, R. S.; Major, S. S. [Center For Research in Nano-Technology and Science (India); Semiconductor Laser Section, RRCAT, Indore-452013 (India); Department of Metallurgical Engineering and Materials Science (India); Department of Physics, Indian Institute of Technology Bombay, Mumbai - 400076 (India)

2012-06-05T23:59:59.000Z

480

Electronic structure of the Ge/RbF/GaAs(100) heterostructure: LCAO calculations  

Science Journals Connector (OSTI)

The electronic structure of Ge/RbF/GaAs(100) system ... known however about their reactivity. In these calculations the reactive contacts were postulated and modelled. ... obtained results, compared with those of...

Barbara Stankiewicz

Note: This page contains sample records for the topic "hg cn 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.


481

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

E-Print Network [OSTI]

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

Liu, Tian-Yu

2005-01-01T23:59:59.000Z

482

Modeling and Characterization of the Magnetocaloric Effect in Ni2MnGa Materials  

SciTech Connect (OSTI)

Magnetic shape memory alloys have great promise as magneto-caloric effect refrigerant materials due to their combined magnetic and structural transitions. Computational and experimental research is reported on the Ni2MnGa material system. The magnetic states of this system have been explored using the Wang-Landau statistical approach in conjunction with the Locally Self-consistent Multiple-Scattering (LSMS) method to explore the magnetic states responsible for the magnet-caloric effect in this material. The effects of alloying agents on the transition temperatures of the Ni2MnGa alloy were investigated using differential scanning calorimetry (DSC) and superconducting quantum interference device (SQUID). Neutron scattering experiments were performed to observe the structural and magnetic phase transformations at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on alloys of Ni-Mn-Ga and Ni-Mn-Ga-Cu-Fe. Data from the observations are discussed in comparison with the computational studies.

Nicholson, Don M [ORNL; Odbadrakh, Khorgolkhuu [ORNL; Rios, Orlando [ORNL; Hodges, Jason P [ORNL; Ludtka, Gerard Michael [ORNL; Porter, Wallace D [ORNL; Sefat, A. S. [Oak Ridge National Laboratory (ORNL); Rusanu, Aurelian [ORNL; Evans III, Boyd Mccutchen [ORNL

2012-01-01T23:59:59.000Z

483

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

484

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

Science Journals Connector (OSTI)

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

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

1984-05-07T23:59:59.000Z

485

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

SciTech Connect (OSTI)

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

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

2013-12-04T23:59:59.000Z

486

Growth and characterization of liquid phase epitaxial GaP layers  

E-Print Network [OSTI]

Inside a High-vacuum Chamber . . . . . . . . . . . . . . . . . . . . . . . 3 3. Cross Section of Multi-well Sliding Graphite Boat. Solubility Curve of P in Ga Melt 5. Apparatus of LPE Growth by Tipping Method. 10 Dipping System Schematic for LPE... Growth. 10 7. Sliding Boat System Block Diagram for LPE Growth 12 Temperature Profile Along the Graphite Boat. 13 9. Disassembled Graphite Boat for Multi-layer LPE Growth. . . 14 10. Ga-P Phase Diagram 17 Solution Cooling Procedure for Three...

Kao, Yung-Chung

2012-06-07T23:59:59.000Z

487

Further observations on the operation of a GaAs polarized electron source  

SciTech Connect (OSTI)

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

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

1990-07-01T23:59:59.000Z

488

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

489

Tunnel optical radiation in In{sub x}Ga{sub 1?x}N  

SciTech Connect (OSTI)

An investigation of tunnel optical radiation in epitaxial layers of n-type In{sub x}Ga{sub 1?x}N grown on p-type GaN by novel plasma based migration enhanced epitaxy is presented. Experimental results of electro-luminescence spectra for In{sub x}Ga{sub 1?x}N/p?GaN hetero-junctions were obtained and they show two well expressed optical bands - one in range 500-540 nm and other in range 550-610 nm. An interesting detail is that each band begins and ends by sharp drops of the radiation, which nearly approach zero. A theoretical investigation of the unusual behavior of these spectra was done using LCAO electron band structure calculations. The optical ranges of these bands show that the radiation occurs in the In{sub x}Ga{sub 1?x}N region. In fact, substitutions of In atoms in Ga sites creates defects in the structure of In{sub x}Ga{sub 1?x}N and the corresponding LCAO matrix elements are found on this basis. The LCAO electron band structures are calculated considering the interactions between nearest-neighbor orbitals. Electron energy pockets are found in both the conduction and the valence bands at the ? point of the electron band structures. Also it is found that these pockets are separated by distances, for which there is overlapping between the electron wave functions describing localized states belonging to the pockets, and as a result tunnel optical radiation can take place. This type of electron transition - between such a pocket in the conduction band and a pocket in the valence band - occurs in In{sub x}Ga{sub 1?x}N, causing the above described optical bands. This conclusion concurs with the fact that the shapes of these bands change with change of the applied voltage.

Alexandrov, Dimiter; Skerget, Shawn [Semiconductor Research Laboratory, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B5E1 (Canada)

2014-02-21T23:59:59.000Z

490

Theoretical investigation of spin-filtering in CrAs/GaAs heterostructures  

SciTech Connect (OSTI)

The electronic structure of bulk zinc-blende GaAs, zinc-blende and tetragonal CrAs, and CrAs/GaAs supercells, computed within linear muffin-tin orbital (LMTO) local spin-density functional theory, is used to extract the band alignment for the [1,0,0] GaAs/CrAs interface in dependence of the spin orientation. With the lateral lattice constant fixed to the experimental bulk GaAs value, a local energy minimum is found for a tetragonal CrAs unit cell with a longitudinal ([1,0,0]) lattice constant reduced by ?2%. Due to the identified spin-dependent band alignment, half-metallicity of CrAs no longer is a key requirement for spin-filtering. Based on these findings, we study the spin-dependent tunneling current in [1,0,0] GaAs/CrAs/GaAs heterostructures within the non-equilibrium Green's function approach for an effective tight-binding Hamiltonian derived from the LMTO electronic structure. Results indicate that these heterostructures are promising candidates for efficient room-temperature all-semiconductor spin-filtering devices.

Stickler, B. A.; Ertler, C.; Pötz, W., E-mail: walter.poetz@uni-graz.at [Institute of Physics, Karl-Franzens Universität Graz, Graz (Austria); Chioncel, L. [Institute of Physics, Theoretical Physics III, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86135 Augsburg (Germany)

2013-12-14T23:59:59.000Z

491

Realizing InGaN monolithic solar-photoelectrochemical cells for artificial photosynthesis  

SciTech Connect (OSTI)

InGaN alloys are very promising for solar water splitting because they have direct bandgaps that cover almost the whole solar spectrum. The demonstration of direct solar-to-fuel conversion without external bias with the sunlight being the only energy input would pave the way for realizing photoelectrochemical (PEC) production of hydrogen by using InGaN. A monolithic solar-PEC cell based on InGaN/GaN multiple quantum wells capable to directly generate hydrogen gas under zero bias via solar water splitting is reported. Under the irradiation by a simulated sunlight (1-sun with 100 mW/cm{sup 2}), a 1.5% solar-to-fuel conversion efficiency has been achieved under zero bias, setting a fresh benchmark of employing III-nitrides for artificial photosynthesis. Time dependent hydrogen gas production photocurrent measured over a prolonged period (measured for 7 days) revealed an excellent chemical stability of InGaN in aqueous solution of hydrobromic acid. The results provide insights into the architecture design of using InGaN for artificial photosynthesis to provide usable clean fuel (hydrogen gas) with the sunlight being the only energy input.

Dahal, R.; Pantha, B. N.; Li, J.; Lin, J. Y.; Jiang, H. X., E-mail: hx.jiang@ttu.edu [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2014-04-07T23:59:59.000Z

492

Heteroepitaxial growth and surface structure of L1{sub 0}-MnGa(111) ultra-thin films on GaN(0001)  

SciTech Connect (OSTI)

L1{sub 0}-structured MnGa(111) ultra-thin films were heteroepitaxially grown on GaN(0001) under lightly Mn-rich conditions using molecular beam epitaxy. Room-temperature scanning tunneling microscopy (STM) investigations reveal smooth terraces and angular step edges, with the surface structure consisting primarily of a 2 × 2 reconstruction along with small patches of 1 × 2. Theoretical calculations were carried out using density functional theory, and the simulated STM images were calculated using the Tersoff-Hamman approximation, revealing that a stoichiometric 1 × 2 and a Mn-rich 2 × 2 surface structure give the best agreement with the observed experimental images.

Mandru, Andrada-Oana; Wang, Kangkang; Cooper, Kevin; Ingram, David C.; Smith, Arthur R. [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States)] [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Garcia Diaz, Reyes; Takeuchi, Noboru [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States) [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Centro de Nanociencias y Nanotecnologia, Universidad Nacional Autónoma de México, Apartado Postal 14, Ensenada Baja California, Codigo Postal 22800 (Mexico); Haider, Muhammad [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States) [Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701 (United States); Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran, 31261 (Saudi Arabia)

2013-10-14T23:59:59.000Z

493

Gain uniformity of InP/InGaAsP/InGaAs avalanche photodiodes with separate absorption, grading, and multiplication regions  

SciTech Connect (OSTI)

We report on the spatial uniformity of the gain M of InP/ InGaAsP/InGaAs avalanche photodiodes with separate absorption, grading, and multiplication regions (SAGM-APD's). Typically, these APD's exhibit less than 10 percent variation in the gain (for M less than or equal to 10) over the entire photosensitive area. The small nonuniformity which is observed shows a one-to-one correspondence with inhomogeneities in the epitaxial layers of the SAGM-APD structure. We also observe a reduction in the effective photosensitive diameter with increasing bias voltage.

Holden, W.S.; Campbell, J.C.; Dental, A.G.

1985-09-01T23:59:59.000Z

494

Frequency response of InP/InGaAsP/InGaAs avalanche photodiodes with separate absorption ''grading'' and multiplication regions  

SciTech Connect (OSTI)

We have measured the frequency response of InP/ InGaAsP/InGaAs photodiodes with separate absorption, ''grading,'' and multiplication regions (SAGM-APD's) for a wide range (2 less than or equal to M/sub 0/ less than or equal to 35) of dc gains. The results are explained in terms of a theoretical model which incorporates the transit time of carriers through the depletion region, the RC time constant, the accumulation of holes at the valence band discontinuity of the heterojunction interfaces, and the gainbandwidth limit.

Campbell, J.C.; Dentai, A.G.; Holden, W.S.; Qua, G.J.

1985-11-01T23:59:59.000Z

495

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

Science Journals Connector (OSTI)

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

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

2007-01-17T23:59:59.000Z

496

How much better are InGaN/GaN nanodisks than quantum wells—Oscillator strength enhancement and changes in optical properties  

SciTech Connect (OSTI)

We show over 100-fold enhancement of the exciton oscillator strength as the diameter of an InGaN nanodisk in a GaN nanopillar is reduced from a few micrometers to less than 40?nm, corresponding to the quantum dot limit. The enhancement results from significant strain relaxation in nanodisks less than 100?nm in diameter. Meanwhile, the radiative decay rate is only improved by 10 folds due to strong reduction of the local density of photon states in small nanodisks. Further increase in the radiative decay rate can be achieved by engineering the local density of photon states, such as adding a dielectric coating.

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

2014-02-03T23:59:59.000Z