| Predicting Electron Transport Using Simulated Axial Waves in a Radial-Axial Hybrid Hall Thruster Model |
Sep-2009 |
12 pages |
| Authors:
Michelle K Scharfe; Mark A Cappelli; Eduardo Fernandez; ENGINEERING RESEARCH AND CONSULTING INC (ERC INC) EDWARDS AFB CA
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 | Axial waves predicted by a two-dimensional hybrid numerical model have been used to estimate electron cross field transport due to tilted waves with azimuthal components. Since the radial-axial hybrid simulation cannot model these tilted waves directly, the predicted axial waves are assumed to couple symmetrically into two counter-propagating axial-azimuthal waves. A linearized two-dimensional dispersion relation is solved to obtain the azimuthal component of wavenumber consistent with the frequency and axial ... |
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| Pendeo-Epitaxy Process Optimization of GaN for Novel Devices Applications |
APR 2008 |
22 pages |
| Authors:
Michael A. Derenge; Tsvetanka S. Zheleva; Kenneth A. Jones; Pankaj B. Shah; Daniel Ewing; J. Molstad; Unchul Lee; Matthew H. Ervin; David N. Stepp; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| A relatively new class of materials known as wide bandgap materials and the corresponding devices fabricated from them have extremely useful characteristics for high temperature, high-frequency, high-power applications in numerous army systems and components. However the technology for these new materials is not mature enough and these materials contain various types of structural defects in high concentrations. It is well known that structural defects degrade the performance of the electronic ... |
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| Hall Thruster Electron Mobility Investigation using Full 3D Monte Carlo Trajectory Simulations (Preprint) |
24 AUG 2007 |
7 pages |
| Authors:
Darren A. Alman; Joshua L. Rovey; Robert A. Stubbers; Brian E. Jurczyk; STARFIRE INDUSTRIES LLC CHAMPAIGN IL
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| Axial electron transport represents a loss in efficiency for crossed field devices, such as Hall-effect thrusters (HETs). Previous experimental and computational investigations have revealed an anomalous axial mobility that cannot be explained with classical theory. This work describes the development of a computational model that calculates electron mobility in HETs using known electric and magnetic fields. Specifically, a full 3D Monte Carlo trajectory simulation code is developed to simulate HET ... |
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| A Planar Hall Thruster for Investigating Electron Mobility in ExB Devices (Preprint) |
24 AUG 2007 |
13 pages |
| Authors:
Joshua L. Rovey; Matthew P. Giacomi; Robert A. Stubbers; Brian E. Jurczyk; STARFIRE INDUSTRIES LLC CHAMPAIGN IL
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| Stable operation of a Hall thruster that emits and collects the Hall current across a planar discharge channel is described. The planar Hall thruster (PHT) is being investigated for use as a test bed to study electron mobility in ExB devices. The planar geometry attempts to de-couple the complex electron motion found in annular thrusters by using simplified geometry. During this initial test, the PHT was operated at discharge voltages ... |
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| Comparison of Numerical and Experimental Near-Field Ion Velocity Distributions of the BHT-200-X3 Hall Thruster |
12 JUL 2006 |
26 pages |
| Authors:
Garrett D. Reed; Jr. Hargus William A.; Douglas B. VanGilder; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| Near-field ion velocity distributions of a BusekBHT-200-X3 xenon Hall thruster obtained through numerical simulation are compared with laser-induced fluorescence measurements taken for one nominal operating condition. The numerical code Hybrid-PIC Hall, a 2D hybrid particle-in-cell model, is used to simulate an axisymmetric cross section of the plasma acceleration zone. A set of nine HP Hall simulations are run using three different cathode positions and Bohm electron mobility coefficients to study ... |
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| Hall Thruster With an External Acceleration Zone |
14 SEP 2005 |
8 pages |
| Authors:
Nicolas Gascon; Ronald L. Corey; Mark A. Cappelli; William Hargus; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
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| This work presents the general operation and the near exit plane ion velocity field of the Stanford Linear Hall Thruster in a high vacuum environment. The ionized propellant velocities were measured using laser induced fluorescence of the excited state xenon ionic transition at 834.7 nm. Ion velocities were interrogated from the channel exit plane to a distance 30 mm from it. Both axial and cross-field (along the electron Hall current ... |
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| Using Electrons on a Helium Film as Qubits |
30 JUN 2005 |
16 pages |
| Authors:
John Goodkind; CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF PHYSICS
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| Electrons, with energy less than 1 eV, when sprayed onto the surface of liquid helium become bound to the surface by the electrostatic image charge in the liquid. Their mobility along the surface is extremely high so that their motion in the plane is essentially unbound. This means that each electron is in a potential like that of a 1D hydrogen atom. |
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| Ion Velocity Measurements in a Linear Hall Thruster |
JUN 2005 |
7 pages |
| Authors:
Nicolas Gascon; Mark A. Cappelli; William A. Hargus Jr; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| This work presents the general operation and the near exit plane velocity field of the Stanford Linear Hall thruster in a high vacuum environment. The ionized propellant velocities were measured using laser induced fluorescence of the excited state xenon ionic transition at 834.7 nm. Ion velocities were interrogated from the channel exit plane to a distance 30 mm from it. Both axial and transverse (along the electron Hall current direction) ... |
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| Wide Band Gap Semiconductor Technology Initiative |
07 JAN 2004 |
14 pages |
| Authors:
Robert F. Davis; NORTH CAROLINA STATE UNIV AT RALEIGH
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| Investigations have been concerned with substrate etching, thin film growth and doping and the growth of pin structures coupled with structural, microstructural, thickness, optical and electrical characterizations. Maps of the FWHM of the x-ray rocking curves reveal that both the number and the degrees of tilt of the domains in the (112-0) wafers were significantly smaller than those observed for the 80 off-axis (0001) as-received wafers. The average FWHM values ... |
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| Mobility and Transverse Electric Field Effects in Channel Conduction of Wrap-Around-Gate Nanowire MOSFETs |
2004 |
10 pages |
| Authors:
A. K. Sharma; S. H. Zaidi; S. Lucero; S. R. Brueck; N. E. Islam; GRATINGS INC ALBUQUERQUE NM
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| The current conduction process through a nanowire wrap-around-gate, ~50 nm channel diameter, silicon MOSFET has been investigated and compared with a ~2 mum wide slab, ~200 nm thick silicon (SOI) top-only-gate planar MOSFET with otherwise similar doping profiles, gate length and gate oxide thickness. The experimental characteristics of the nanowire and planar MOSFETs were compared with theoretical simulation results based on semiempirical carrier mobility models. The SOI nanowire MOS devices ... |
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| Plasma Wave Electronic Terahertz Technology |
23 MAY 2003 |
22 pages |
| Authors:
Michael S. Shur; RENSSELAER POLYTECHNIC INST TROY NY DEPT OF ELECTRICAL COMPUTER AND SYSTEMS ENGINEERING
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| Plasma waves are oscillations of electron density in time and space. In deep submicron field effect transistors plasma wave frequencies lie in the terahertz range and can be tuned by applied gate bias. Since the plasma wave frequency is much larger that the inverse electron transit time in the device, it is easier to reach "ballistic" regimes for plasma waves than for electrons moving with drift velocities. In the ballistic ... |
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| InAs Device Process Development and Characterization |
19 MAY 2003 |
46 pages |
| Authors:
Kiki Ikossi; NAVAL RESEARCH LAB WASHINGTON DC ELECTRONICS SCIENCE AND TECHNOLOGY DIV
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| This report summarizes the results of the initial effort in InAs bipolar device development. InAs is one of the III-V semiconductor materials exhibiting a relatively small energy bandgap and extremely high electron mobility, properties both desirable for high-frequency, low-power dissipation device applications. The major accomplishment of this work is the development of a robust device fabrication process that can be directly transferred to an industrial environment. Ti/Pt/Au was used as ... |
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| Development of SiC Power MOSFETs with Low On-Resistance for Military and Commercial Applications |
31 MAR 2003 |
251 pages |
| Authors:
James A. Cooper Jr; PURDUE UNIV LAFAYETTE IN SCHOOL OF ELECTRICAL AND COMPUTER ENGINERING
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| A large number of applications for power switching devices lie in the voltage range from 600-1800 V. In this regime, the specific on-resistance of SiC power MOSFETs is limited by their MOS channel resistance, due to the low inversion layer electron mobility at the SiO2/SiC MOS interface. Although significant progress has been made in increasing the electron mobility, it is still about an order-of-magnitude lower than in silicon devices. Our ... |
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| Classical Collisional Diffusion in the Annular Penning Trap |
24 JUN 2002 |
9 pages |
| Authors:
Qudsia Quraishi; Scott Robertson; Bob Walch; COLORADO UNIV AT BOULDER DEPT OF PHYSICS
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| Transport of particles and energy by cross-field diffusion has been studied in the annular Penning trap in which a nonneutral plasma of electrons is contained between concentric cylinders. At densities sufficiently low ( |
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| Magnetic Shear Stabilization of Diocotron Instability |
24 JUN 2002 |
6 pages |
| Authors:
S. Kondoh; T. Tatsuno; Z. Yoshida; TOKYO UNIV (JAPAN) GRADUATE SCHOOL OF FRONTIER SCIENCES
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| The diocotron instability in a magnetized non-neutral plasma is a close cousin of the Kelvin-Helmholtz instability. A sheared magnetic field brings about coupling between the diocotron modes and the Langmuir waves that propagate along the magnetic field. Motion of electrons parallel to the magnetic field cancels the electric charge produced by the diocotron modes, resulting in stabilization of the diocotron instability. |
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| Compliant Substrate for Mid Infrared Wavelength Region |
24 JUN 2002 |
52 pages |
| Authors:
Shanthi Iyer; NORTH CAROLINA AGRICULTURAL AND TECHNICAL STATE UNIV GREENSBORO DEPT OF ELECTRICAL ENGINEERING
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| The work in this project was focused on the growth of GaSb epilayer on a compliant layer by Molecular Beam Epitaxial (MBE) technique. A novel approach using the low temperature melting interlayer and a thin strained layer on top was investigated for compliancy. The structures examined consisted of GaAs host substrate, InSb as the low melting point interlayer, thin (Ga,Al) Sb layer, followed by thick GaSb overlayer. Growth results and ... |
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| Approaches to Advanced Materials for Photorefractive Applications and Radiation Hardening |
01 JUN 2002 |
39 pages |
| Authors:
Seth R. Marder; ARIZONA UNIV TUCSON DEPT OF CHEMISTRY
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| We have made considerable advances in the development of optical- limiting systems based upon two-photon absorption processes. To accomplish this, it has been essential to develop an understanding of basic structure-property relationships for conjugated organic materials. To this end, we have investigated a range of phenylene-vinylene-based materials substituted with various combinations of donor and acceptor moieties. We now have a more thorough understanding of how to design materials with very ... |
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| Conjugated Polyelectrolytes: Synthesis and Applications |
28 APR 2002 |
18 pages |
| Authors:
Mauricio R. Pinto; Kirk S. Schanze; FLORIDA UNIV GAINESVILLE DEPT OF CHEMISTRY
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| Conjugated polyelectrolytes are conjugated polymers that feature ionic side groups which render the materials soluble in water and other polar solvents. In this review we summarize recent work which has been carried out to synthesize a variety of new conjugated polyelectrolyte structures, including those with poly(paraphenylene), poly(phenylene vinylene) and poly(phenylene ethynylene) backbone structures. Work that has examined the optical, photophysical and solution properties of these materials is also reviewed. Finally, ... |
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| High Power, Broadband, Linear, Solid State Amplifier |
JAN 2002 |
6 pages |
| Authors:
Lester F. Eastman; CORNELL UNIV ITHACA NY SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING
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| During the period from September 1 December 3 1, 2001, effort continued on this MURI contract, after an approved extension, using unrestricted grants from industry. This report briefly covers the highlights of the program during this period. The two key areas covered are the undoped materials growth, and the AlGaN/GaN HEMT performance. |
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| Development of AIIBVI Semiconductors Doped with Cr for IR Laser Application |
JAN 2002 |
5 pages |
| Authors:
V. A. Kasiyan; R. Z. Shneck; Z. M. Dashevsky; S. R. Rotman; BEN-GURION UNIV OF THE NEGEV BEERSHEBA (ISRAEL)
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| Electrical and optical measurements obtained with CdSe single crystals doped with chromium from a gas source CrSe over a wide temperature range (500 - 1050 deg C) are compared with ZnSe annealed in liquid metal (Zn). These processes are intended to control the concentrations of the impurity and intrinsic defects. The low temperature annealing of CdSe crystals in CrSe atmosphere allows obtaining high electron mobility up to 9000 sq cm/Vs ... |
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| Sputter Deposition Method for III-V Semiconductor |
03 NOV 2001 |
38 pages |
| Authors:
Curt M. Lampkin; SOLAR ASSOCIATES MERRITT ISLAND FL
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| The major effort in the program has been the development of a microwave source to lower the sputter plasma voltage. I originally proposed an electron gun. However, the electron gun had a fundamental flaw. It extinguished the plasma near its insertion point with a resulting non-uniform deposition. |
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| Materials Development Research |
SEP 2001 |
135 pages |
| Authors:
Emmanuel E. Boakye; Peter M. Hazzledine; Kristin A. Keller; Young-Won Kim; Pavel Mogilevsky; UES INC DAYTON OH
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| Research has been carried out in three materials systems: (1) Advanced Metallics: NbTi/silicides and gamma TiAl are being developed as high- temperature structural materials. The research included chemistry/processing/ microstructure/property relations to provide a balance in mechanical properties and oxidation resistance. Fundamental studies on microstructures and mechanical behavior in these systems have been performed using a variety of analytical and computational tools to predict aspects of plasticity, creep and fracture on ... |
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| Spontaneous Magnetization in Single and Coupled Quantum Dots |
JUN 2001 |
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| Authors:
I. I. Yakimenko; A. M. Bychkov; K. F. Berggren; LINKOEPING UNIV (SWEDEN) DEPT OF PHYSICS AND MEASUREMENT TECHNOLOGY
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 | Spontaneous magnetization of single and coupled quantum dots formed by lateral confinement of a high-mobility two-dimensional electron gas is studied for a realistic semiconductor heterostructure. The modeling of the device takes into account contributions from a patterned gate doping, surface states and mirror charges. To explore the magnetic properties we use the Kohn- Sham local spin-density formalism including the contributions from electron correlation as well as from exchange. We show, ... |
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| Dilation of the Giant Vortex State in a Mesoscopic Superconducting Loop |
JUN 2001 |
|
| Authors:
S. Pedersen; G. R. Kofod; J. C. Hollingbery; C. B. Soerensen; P. E. Lindelof; COPENHAGEN UNIV (DENMARK) NIELS BOHR INST
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| We have experimentally investigated the magnetisation of a mesoseopie aluminum loop at temperatures well below the superconducting transition temperature T(c). The flux quantisation of the superconducting loop was investigated by a mu-Hall magnetometer in magnetic intensities beween +/- 100 Gauss. The magnetic intensity periodicity observed in the magnetisation measurements corresponds to integer values of the supereonducting flux quantum Phi(0) = h-bar/2e. A closer inspection of the periodicity however reveal a ... |
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| The Bloch Oscillations and Mobile Electrical Domains in 6H-SiC Natural Superlattice |
JUN 2001 |
3 pages |
| Authors:
V. I. Sankin; P. P. Shkrebiy; RUSSIAN ACADEMY OF SCIENCES SAINT PETERSBURG IOFFE PHYSICAL-TECHNICAL INST
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| The discovenng of NDC and mobile domain due to Bloch oscillations are the more important results in study the strong field transport in SiC superlattice. The presence of unusual mobile domain creating the breakdown avalanche is evidence oscillations possibly with terra Hz frequency. |
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| Large Increase of Electron Mobility in a Modulation-Doped AlGaAs/GaAs/AlGaAs Quantum Well with an Inserted Thin AlAs Barrier |
JUN 2001 |
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| Authors:
K. Pozela; J. Poleza; V. Juciene; SEMICONDUCTOR PHYSICS INST VILNIUS (LITHUANIA)
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| The electron (polar optical (PO)) phonon scattering mechanisms which determine the electron mobility in a Al(0.25)Ga(0.75) As/GaAs/Al(0.25) Ga(0.75). As quantum well (QW) with an inserted thin AlAs barrier are considered. It is shown that the decrease of the second subband electron scattering by PO-phonon emission is responsible for the large increase of the mobility in the QW with the inserted barrier. |
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| Strained and Unstrained Bi(1-x)Sb(x) Superlattice Thermoelectrics |
19 MAY 2001 |
72 pages |
| Authors:
John B. Ketterson; Arthur J. Freeman; Jerry R. Meyer; George K. Wong; Antonio DiVenere; NORTHWESTERN UNIV EVANSTON IL DEPT OF PHYSICS AND ASTRONOMY
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| The electronic band structure of artificially ordered superlattice alloys (SLA) of Bi and Sb, prepared by alternately depositing thin layers of Bi and Sb as a superlattice, could be modified from a semimetal to a semiconductor by changing the period of the superlattice. This new SLA opens a possibility to engineer an alloy material to get more desirable thermoelectric properties, because a thermal conductivity reduction, due to an increase in ... |
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| Composition-Morphology-Property Relations for Giant Magnetoresistance Multilayers Grown by RF Diode Sputtering |
APR 2001 |
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| Authors:
W. Zou; H. N. Wadley; X. W. Zhou; R. A. Hohnson; D. Brownell; VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| A series of experiments have been conducted to evaluate the magnetotransport properties of RF diode sputter deposited giant magnetoresistive (GMR) multilayers with either copper or copper-silver-gold nonferromagnetic (NFM) conducting layers. The study revealed that RF diode deposited multilayers utilizing Cu80Ag15Au5 as the NFM conducting layer posses significantly superior giant magnetoresistance to otherwise identical device architectures that used pure copper as the NFM conducting layer. To explore the origin of this ... |
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| SiC Discrete Power Devices |
01 JAN 2001 |
130 pages |
| Authors:
Ravi K. Chilukuri; B. J. Baliga; NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| A novel planar vertical MOSFET structure, called ACCUFET, which eliminates both the problem of premature oxide breakdown and low inversion layer mobility has been demonstrated at Power Semiconductor Research Center. The contributions of the parasitic JFET regions in the ACCUFET to its forward conduction and forward blocking characteristics are discussed for the first time. A new process for fabrication of high voltage 4H-SiC ACCUFETs has been designed using insights gained. ... |
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| Modeling of the Carrier Mobility at the Silicon Oxynitride-Silicon Interface |
2001 |
5 pages |
| Authors:
K. J. Plucinski; MILITARY UNIV OF TECHNOLOGY WARSAW (POLAND)
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| The main issue which is yet to be resolved in further developing the Surface Channel MOSFETs (SCMOSFETs) is understanding and eliminating deterioration of the carrier mobility at the insulator-semiconductor interface. The main factor causing this deterioration is hole and electron trapping-detrapping. One of the ways recently suggested of minimizing hole and electron trapping-detrapping at the Si-SiO2 interface involves replacing the SiO2 by silicon oxynitride (SiON). However degradation of MOSFETs, which ... |
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| From Honey-Comb to SMMIC: Schottky Diodes at TU Darmstadt |
29 SEP 2000 |
4 pages |
| Authors:
Chih Lin; Victoria Ichizli; Manuel Rodriguez-Girones; Mustafa Saglam; Pawel Szeliga; TECHNISCHE HOCHSCHULE DARMSTADT (GERMANY F R) INST FUER HOCHFREQUENZTECHNIK
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| GaAs Schottky diode proved itself to be one the main semiconductor device used in THz-electronics. This contribution describes the evolution of THz-devices from honey-comb whisker-contacted Schottky diodes to sub-millimetre monolithically integrated circuits (SMMIC) at University of Technology (TU) Darmstadt. Short description of each device and integration type is given together with pointing technological and device particularities. |
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| An InGaAs/InAlAs Superlattice Oscillator for Frequencies Above 100 GHz |
29 SEP 2000 |
3 pages |
| Authors:
R. Scheuerer; E. Schomburg; A. Ignatov; K. F. Renk; D. G. Pavelev; INSTITUTE FOR RADIOPHYSICS NIZHNY NOVGOROD (RUSSIA)
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| We present an InGaAs/InAlAs superlattice oscillator at 150 GHz with a superlattice device mounted in a waveguide and biased at a voltage of 1.3 V (current 15 mA), radiation of a power of 0.1 mW was generated. In the doped superlattice, the electron motion is governed by miniband transport, leading to a negative differential conductance due to Bragg reflection of the electrons at the miniband boundary. As a consequence, propagating ... |
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| Long-Wavelength Vertical Cavity Lasers with Air/Semiconductor Mirrors: Nanoscale Gate Technology for Silicon MOSFETS |
JUL 2000 |
4 pages |
| Authors:
Jeffrey Bokor; Nick Lindert; CALIFORNIA UNIV BERKELEY ELECTRONICS RESEARCH LAB
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| We have investigated methods to improve sub-100 nm MOSFET performance. We discovered that Poly-SiGe has very attractive qualities when used as the transistor gate material. Poly-SiGe offers less boron penetration, less poly depletion, and higher hole mobility. Dynamic Threshold MOSFET (DTMOS) techniques were also investigated to allow for improved inverter drive current over a broader range of supply voltages. We applied these techniques to various ... |
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| High Power, Broadband, Linear, Solid State Amplifier |
SEP 1999 |
43 pages |
| Authors:
Lester F. Eastman; Vinayak Tilak; Kenneth Chu; O. Ambacher; Nils Weimann; CORNELL UNIV ITHACA NY SCHOOL OF ELECTRICAL ENGINEERING
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| Large periphery AlGaN/GaN HEMT's gave normalized power > 2 W/mm, and > 4 W/mm on sapphire and SiC substrates, respectively. A new processing method, using photolithography for all steps except for the gate, is being developed to reduce cost and raise throughput and reproducibility. The properties of the two- dimensional electron gas in undoped HEMT structures are compared with theory and explained by a combination of spontaneous and piezoelectric polarization, ... |
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| BAF2/GAAS Electronic Components. |
03 AUG 1999 |
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| Authors:
Francisco Santiago; Tak K. Chu; DEPARTMENT OF THE NAVY WASHINGTON DC
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| Metal insulator semiconductor field effect transistors (MISFETs), charge coupled devices (CCDs), and capacitors based on an epitaxial barium fluoride (BF) insulator layer deposited directly onto a single crystal gallium arsenide (GaAs) substrate. |
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| Device Characteristics of VLWIR MCT Photodiodes |
AUG 1999 |
9 pages |
| Authors:
R. E. DeWames; P. S. Wijewarnasuriya; W. McLevige; D. Edwall; G. Hildebrandt; ROCKWELL INTERNATIONAL CORP THOUSAND OAKS CA SCIENCE CENTER
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| We have characterized the current-voltage characteristics, spectral response and quantum efficiencies of Hg(1-x)Cd(x)Te photodiodes with x values equal to .209 and .194. The devices studied are double layer planar heterojunctions (DLPHJ) photodiodes fabricated by MBE. Arsenic ion implantation is used to form the heavily doped p-side. The base is indium-doped at carrier density levels of ^5x10(exp 14)/cu cm. For x - 0.194 at T =30K, the bandgap wavelength, lamba(g) is ... |
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| Observation of Negative Persistent Photoconductivity in GaAs delta-Doped by Sn |
18 JUN 1999 |
4 pages |
| Authors:
V. A. Kulbachyinskii; V. G. Kytin; R. A. Lunin; A. V. Golikov; A. V. Demin; AKADEMIYA NAUK SSSR MOSCOW INST RADIOTEKHNIKI I ELEKTRONIKI
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| GaAs delta-doped structures with various Sn doping densities have been grown on vicinal substrates. The observed at low temperatures negative persistent photoconductivity in heavily delta-doped samples is connected with increase of electron concentration and decrease of electron mobilities. Such effect may occur when the correlations among charged shallow donors and DX- centers are destroyed via photoexcitation of electron out of the DX- centers. The observed in samples with electron concentration ... |
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| Electrical Characterization of Ion-Implanted 4H-Silicon Carbide |
MAR 1999 |
166 pages |
| Authors:
Christian P. Morath; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH
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| Electrical characterization has been performed on ion-implanted p- type 4H-SiC to assess the activation efficiency and implantation-related damage recrystallization with the intention of developing an implantation/annealing scheme. Low doped (Na - Nd = 5x10(exp 15)/cu cm) epitaxial p-type layers grown by MOCVD were implanted with Al or B at doses ranging from 1x10(exp 13) to 1x10(exp 14)/sq cm at room temperature or 500 deg. C. ... |
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| Concentration Fluctuation Degradation of FPA'S |
1999 |
8 pages |
| Authors:
A. Sher; M. W. Muller; SRI INTERNATIONAL MENLO PARK CA
|
| Semiconductor alloys like Hg(1-x)Cd(x)Te and Al(1-x)Ga(x)As, where there is a close lattice constant match between the constituents, are nearly random. However, for mesoscopic size scales of radius r, that are large compared with a lattice constant (^25 A |
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| Chalcopyrite Materials Model--CM2 (Electronic Structure and Transport Properties) |
04 DEC 1998 |
9 pages |
| Authors:
Frank L. Madarasz; ALABAMA UNIV IN HUNTSVILLE RESEARCH INST
|
| Electronic transport measurements are a method of obtaining quantitative data about a semiconductor material. The measurement of the conductivity and Hall mobilities and the subsequent analysis can determine the important processes limiting the materials usefulness. For the case of Cadmium Germanium Diarsenide (CGA), saturation at higher pump power in laser systems limits its usefulness as an optical parametric oscillator (OPO) and frequency doubler. The observed saturation has been attributed to ... |
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| Theory of Non-linear Plasma Waves in FETs |
25 JUL 1998 |
13 pages |
| Authors:
Guram Samsonidze; RUSSIAN ACADEMY OF SCIENCES ST PETERSBURG IOFFE PHYSICAL- TECHNICAL INST
|
| This report describes the results of the investigation of nonlinear effects in the plasma oscillations in bounded electron systems. We studied an evolution of electron density distribution in the conduction channel of a Field Effect Transistor under various boundary conditions. The decay law of shock like waves in dynamically closed systems was found. We investigated the effects of plasma waves in the nonlinear response of the ... |
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| Correlated Dopant Distributions in Delta-Doped Layers |
JUN 1998 |
6 pages |
| Authors:
P. M. Koenraad; EINDHOVEN UNIV OF TECH (NETHERLANDS)
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| In this paper we discuss the observation of correlations in the spatial distribution of Be atoms in delta doped layers. In Si delta doped samples we show that correlations in the charge distribution occur when DX centers are populated. The mobility enhancement we measure in our structures agrees with the calculated enhancement due to correlations effects. |
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| Fabrication and Electron Transport Properties of Superconducting-Normal Metal (Ballistic) Nanostructures |
JUN 1998 |
4 pages |
| Authors:
G. M. Mikhailov; I. V. Malikov; RUSSIAN ACADEMY OF SCIENCES CHERNOGOLOVKA INST OF MICROELECTRONICS AND HIGH PURITY MATERIALS
|
| Experiments with ballistic weak link, where coherent Andreev's reflection may taken place, are of great interest. Recently, such type expenments were carried out using high electron rnobllity 2 DEG of semiconductor heterostructures contacted to the superconductors. Developing of monocrystalline metallic nanostructure fabrication capable ballistic electron transport makes it possible to fabricate superconductor normal metal (ballistic) structures, including also heteroepitaxial multilayered nanostructures. In this report we present for the first time ... |
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| Basic Studies in Plasma Physics |
31 JAN 1998 |
29 pages |
| Authors:
Lebowitz; RUTGERS - THE STATE UNIV NEW BRUNSWICKNJ
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| An improved understanding of equilibrium and non-equilibrium properties of plasmas is central to many areas of basic science as well as to the development and optimal utilization of plasmas in various technologies. This involves the study of the large variety of phenomena which take place when neutral, partially ionized atoms and electrons interact strongly with external fields and with each other in a plasma. It includes ... |
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| Theory of Indium Thallium Phosphide |
15 JAN 98 |
52 pages |
| Authors:
S. Krishnamurthy; SRI INTERNATIONAL MENLO PARK CA
|
| We have used a combination of first principles and empirical band structures to study various properties of new classes of IR materials, the III-V alloys In(1-x)TlxQ, where Q=P, As, or Sb: temperature variation of the band gap, absorption coefficient, minority carrier lifetimes, thermodynamic phase diagram, low-field electron and hole mobilities, native point defect (such as vacancies and antisites) concentrations, parameters needed for modeling MBE growth. We found that, in the ... |
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| Molecular Beam Epitaxy of Sb-based Semiconductors |
1998 |
53 pages |
| Authors:
Brian R. Bennett; B. V. Shanabrook; NAVAL RESEARCH LAB WASHINGTON DC
|
| The growth of semiconductor antimonides by molecular beam epitaxy (MBE) was first reported in the late 1970's. In recent years, the emergence of several potential device applications has resulted in increased activity in the field. Much of the work focuses on GaSb and AlSb because they are nearly lattice-matched to each other and to InAs (a sub o,AlSb=6.1355 A, a sub o, GaSb=6.0954 A, a sub ,InAs=6.0584 A). These semiconductors ... |
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| Study of the Growth, by Solid State Recrystallization, and Assessment of ZnSe Crystals as Substrates for Blue Emitting Devices |
NOV 97 |
17 pages |
| Authors:
Robert Triboulet; EUROPEAN RESEARCH OFFICE LONDON (UNITED KINGDOM)
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| For a better understanding and control, the process of solid state recrystallization of ZnSe is studied through the different aspects of growth kinetics, influence of residual impurities on the kinetics, initial texture/ orientation of the growing crystals' relationship, twinning issue, determination of the vacancy concentration, and doping. An activation energy of tilde 400 kJ/ mole is determined for the migration of the grain boundaries at the early stage of the ... |
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| Nanoflyer |
13 OCT 97 |
12 pages |
| Authors:
J. Katz; R. Garwin; W. Press; MITRE CORP MCLEAN VA JASON PROGRAM OFFICE
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| A recent proposal to use electrostatic forces to lift and propel a small airborne vehicle is examined. We show here that although this is permitted by the laws of physics, it is very inefficient, and is limited to low areal loads by the requirement to avoid electric breakdown. Electrostatic propulsion offers no special advantages which might justify the price of its inefficiency. |
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| Applications of Cd2SnO4 Transparent Conducting Oxides in CdS/CdTe Thin- Film Devices |
SEP 1997 |
6 pages |
| Authors:
X. Wu; P. Sheldon; T. J. Coutts; D. H. Rose; H. R. Moutinho; NATIONAL RENEWABLE ENERGY LAB GOLDEN CO
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| An unusual processing scheme has been developed for preparing single- phase cadmium stannate (Cd2SnO4 or CTO) films. Cd2SnO4 transparent conducting oxide (TCO) films have several significant advantages over conventional TCOs when applied to CdS/CdTe thin-film devices. They are more conductive, more transparent, have lower surface roughness, are patternable, and are exceptionally stable. Cd2SnO4-based CdS/CdTe polycrystalline thin-film solar cells with efficiencies of 14% have been ... |
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| High Power, Broadband, Linear, Solid State Amplifier |
SEP 97 |
48 pages |
| Authors:
Lester F. Eastmen; K. Chu; N. Weimann; B. Green; M. Murphy; CORNELL UNIV ITHACA NY DEPT OF ELECTRICAL ENGINEERING
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| A1GaN/GaN MODFET's grown by MBE and OMVPE with less than 25, micrometers gate lengths, yield up to 50 and 100 GHz for fk and fmax respectively. A substantial effort on circuits for combining power, including both direct power combining and traveling wave combining has been started, along with experimental studies of large pheriphery devices. A new analytical model for the effect of dislocations on electron mobility has been made, and ... |
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ELECTRON MOBILITY
