| Transport Imaging: Developing an Optical Technique to Characterize Bulk Semiconductor Materials for Next Generation Radiation Detectors |
Jun-2009 |
79 pages |
| Authors:
Sarah L Catalano; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | Characterization of the mobility-lifetime product is critical to the development of new materials for semiconductor radiation detectors. An optical technique has been developed that allows for the direct determination of the minority carrier diffusion length, drift length, and mobility-lifetime product from a single image of the recombination luminescence in semiconductor materials. Excess carriers are generated using the electron beam in a scanning electron microscope. The charge is then drifted by ... |
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| A New Method for Growth and Analysis of Next-generation Infrared (IR) Detector Materials |
Mar-2009 |
20 pages |
| Authors:
John D Demaree; Stefan Svensson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| This report describes the development of a new analysis and crystal growth method for next generation infrared materials, namely, dilute nitride III-V semiconductors, which may be used in future low-cost night vision systems. The key to this method is isotopic enrichment of nitrogen-15 during material growth via molecular beam epitaxy, which allows enhanced detection of nitrogen using resonant nuclear reaction analysis. We synthesized films of gallium arsenide nitride (GaAsN) using ... |
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| Investigations of a Coherently Driven Semiconductor Optical Cavity QED System |
30-Sep-2008 |
19 pages |
| Authors:
Kartik Srinivasan; Christopher P Michael; Raviv Perahia; Oskar Painter; NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD
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| Chip-based cavity quantum electrodynamics QED devices consisting of a self-assembled InAs quantum dot QD coupled to a high quality factor GaAs microdisk cavity are coherently probed through their optical channel using a fiber taper waveguide. We highlight one particularly important aspect of this all-fiber measurement setup, which is the accuracy to which the optical coupling level and optical losses are known relative to typical free-space excitation techniques. This allows for ... |
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| Millimeter Wave Modulators Using Quantum Dots |
Sep-2008 |
13 pages |
| Authors:
Dennis W Prather; DELAWARE UNIV NEWARK DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| In this effort electro-optic modulators for millimeter wave sensing and imaging were developed and demonstrated via design, fabrication, and experimental characterization of multi layer quantum dot structures for enhanced electro-optic interaction. Millimeter waves carry small amounts of energy inspiring us to maximize the electro-optic (EO) effect in the developed sensor material. Traditional bulk materials do not have high enough EO coefficients for this application so the goal is to custom ... |
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| Deterministic Entangled Nanosource |
Aug-2008 |
10 pages |
| Authors:
Galina Khitrova; ARIZONA UNIV TUCSON
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| During the three years of this grant, conclusions were reached that are important for the future of semiconductor cavity QED utilizing photonic crystal nanocavities. A new way was found to scan the cavity mode by condensation of xenon or nitrogen while keeping the quantum dot cold to minimize dephasing. Absorption was shown to reduce the cavity Q when the dot density is 400 per square micron. Lasing with a soft ... |
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| Deterministic Entangled Nanosource |
Aug-2008 |
10 pages |
| Authors:
Galina Khitrova; ARIZONA UNIV TUCSON
|
| During the three years of this grant, conclusions were reached that are important for the future of semiconductor cavity QED utilizing photonic crystal nanocavities. A new way was found to scan the cavity mode by condensation of xenon or nitrogen while keeping the quantum dot cold to minimize dephasing. Absorption was shown to reduce the cavity Q when the dot density is 400 per square micron. Lasing with a soft ... |
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| Understanding/Modelling of Thermal and Radiation Benefits of Quantum Dot Solar Cells |
11-Jul-2008 |
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| Authors:
Ryne P Raffaelle; ROCHESTER INST OF TECH NY
|
 | The radiation and thermal dependence of strain compensated InAs QD/ GaAs solar cells have been investigated. Strain compensation is a key step in realizing high efficiency quantum dots solar cells (QDSC). InAs quantum dots (QDs) are grown using the Stranski-Krastenov growth mode which relies on strain, resulting from the mismatch between the InAs and the GaAs lattice parameters, to initiate three-dimensional growth. The generation of QDs does reduce the local ... |
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| Femtosecond Laser Passivation of GaAs Detector Material |
07-Jun-2008 |
9 pages |
| Authors:
MARTIN RICHARDSON; Glenn Boreman; Kathleen Richardson; UNIVERSITY OF CENTRAL FLORIDA ORLANDO CENTER FOR RESEARCH IN ELECTRO-OPTICS AND LASERS
|
| As devices become physically thinner, the surface to volume ratio becomes larger, so the control of surface properties becomes increasingly important. The device surface needs to be passivated in order to reduce electronically active surface states that cause noise. This seedling grant studies a new approach to passivating surfaces and has great Air Force relevance due to its importance in making smaller electronic devices. The objective is to explore the ... |
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| Spin-Precession Organic Magnetic Sensor |
11-Apr-2008 |
43 pages |
| Authors:
Srini Krishnamurthy; SRI INTERNATIONAL MENLO PARK CA
|
| The three major tasks we addressed in this project were to: (a) identify the issues for demonstration of a polymer-based spin-precession magnetic sensor; (b) develop theoretical and computational techniques to study the effect of the interface between ferromagnetic metal and polymers for FET applications; and (c) apply the existing light propagation codes to study transmission of 1.5 micron wavelength light through GaAs. We have completed all three tasks, and the ... |
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| Slow Light in Semi-Conductor Quantum Well Waveguides |
14 FEB 2008 |
7 pages |
| Authors:
Constance Chang-Hasnain; Hailin Wang; Shun-Lien Chuang; Philip Hemmer; CALIFORNIA UNIV REGENTS BERKELEY
|
| The main objective of the program is to investigate various physical phenomena and device structures that can lead to potential applications to all optical storage and processing. The physical effects include electro-magnetic ally induced transparency (EIT), coherent population oscillation (CPO) in semiconductor quantum wells (QW) or dots. We carried out experimental implementation of EIT from electron spin coherence in a GaAs quantum well waveguide for the first time. We designed ... |
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| Wafer-Fused Orientation-Patterned GaAs |
13 FEB 2008 |
9 pages |
| Authors:
Jin Li; David B. Fenner; Krongtip Termkoa; Mark G. Allen; Peter F. Moulton; Candace Lynch; David F. Bliss; William D. Goodhue; MASSACHUSETTS UNIV LOWELL
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| The fabrication of thick orientation-patterned GaAs (OP-GaAs) films is reported using a two-step process where an OP-GaAs template with the desired crystal domain pattern was prepared by wafer fusion bonding and then a thick film was grown over the template by low pressure hydride vapor phase epitaxy (HVPE). The OP template was fabricated using molecular beam epitaxy (MBE) followed by thermocompression wafer fusion, substrate removal, and lithographic patterning. On-axis (100) ... |
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| Surface Modification Engineered Assembly of Novel Quantum Dot Architectures for Advanced Applications |
09-Feb-2008 |
58 pages |
| Authors:
Anupam Madhukar; Priya Vashishta; Aiichiro Nakano; Paul Alivisatos; Rajiv K Kalia; D H Rich; S Chou; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES SCHOOL OF ENGINEERING
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| This DURINT program proposed and undertook several ground-breaking efforts aimed at exploring novel and innovative composite nanostructures created from the integration of the two classes of nanostuctures - the epitaxial nanostructures (e.g. quantum wells) and the nanocrystal quantum structures (e.g. quantum dots). This Final Technical Report summarizes the objectives pursued and major accomplishments. The highlights include the following firsts: (1) demonstration of nonradiative resonant excitation transfer from adsorbed NCQDs to ... |
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| Transport Imaging for the Study of Nanowires and Related Nanostructures |
DEC 2007 |
105 pages |
| Authors:
Ang G. Hwee; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The goals of this thesis are to demonstrate the operation of a near-field scanning microscope (NSOM) inside a scanning electron microscope (SEM) to collect spatially resolved luminescence and to image transport on nano-scale structures particularly nanowires. The SEM is used to generate localized charge and the NSOM is used to observe the motion of the excess charge due to diffusion and/or drift via its recombination emission. This will allow direct ... |
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| Bipolar Cascade Vertical-Cavity Surface-Emitting Lasers for RF Photonic Link Applications |
SEP 2007 |
154 pages |
| Authors:
William J. Siskaninetz; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The development and demonstration of bipolar cascade vertical cavity surface emitting lasers is presented. The systematic approach to designing, fabricating, and characterizing the critical tunnel junction, incorporating the tunnel junction into an edge emitting bipolar cascade laser, and finally the transition to a VCSEL structure is detailed. A novel approach prior to growing and characterizing BC VCSELs was to investigate bipolar cascade light emitting diodes which incorporate the microcavity designs ... |
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| Dilute-Nitride Type-II Quantum Well Lasers Grown by MOCVD |
25 FEB 2007 |
31 pages |
| Authors:
Luke J. Mawst; WISCONSIN UNIV-MADISON
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| One challenging goal remaining for GaAs-based InGaAsN QW lasers is to extend the emission wavelength beyond 1.3 m, while maintaining optical material quality for the realization of longer wavelength and high performance. Higher N-content leads to increased nonradiative monomolecular recombination, thus high performance at 1.55 m has not been achieved to date. Recently, we proposed a novel approach for realizing GaAs-based diode lasers with emission wavelengths beyond =1500 nm. This ... |
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| Slow Light and Adiabatic Bandwidth Variation in Semiconductor Nanostructures |
23 FEB 2007 |
9 pages |
| Authors:
Hailin Wang; OREGON UNIV EUGENE RESEARCH SERVICES AND ADMINISTRATION
|
| We have demonstrated a mechanism of tunable optical delay that takes advantage of the strong Coulomb interactions between excitons and free carriers and uses optical injection of free carriers to broaden and bleach an exciton absorption resonance. Fractional delay exceeding 200% has been obtained for an 8 ps optical pulse propagating near the heavy-hole excitonic transition in a GaAs quantum well (QW). We have also developed a scheme of using ... |
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| Evolution of the Department of Defense Millimeter and Microwave Monolithic Integrated Circuit Program |
FEB 2007 |
168 pages |
| Authors:
William C. Pittman; ARMY AVIATION AND MISSILE RESEARCH DEVELOPMENT ENG CTR REDSTONE ARSENA AL APPLIED SENSORS GUIDANCE AND ELECTRONICS DIRECTORATE
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| The Millimeter and Microwave Monolithic Integrated Circuits (MIMIC) program had its origins in the concern of the smart weapons community for the affordable production of millimeter wave missile seekers, but the broad-based applicability of the technology to radar, communications, countermeasures, and counter-countermeasures was recognized in the formulation of the program. The program was initiated in the turbulent 1980s during the period of high technology trade deficits (and the defense buildup) ... |
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| Device Demonstration |
31 DEC 2006 |
190 pages |
| Authors:
BAE SYSTEMS ELECTRONICS AND INTEGRATED SOLUTIONS NASHUA NH
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| The goal of the Defense Advanced Research Projects Agency (DARPA) Advanced Lithography research program was to revolutionize semiconductor lithography through accelerated research of highly innovative approaches that would enable pattern transfer to wafers of features 100 nm and below. To this end, DARPA, via a Broad Agency Announcement, BAA 00-04, solicited proposals for R&D to understand and overcome specific technological obstacles to the realization of lithography for critical dimensions of ... |
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| Spin Interactions and Spin Dynamics in Electronic Nanostructures |
31 AUG 2006 |
28 pages |
| Authors:
Robert A. Buhrman; CORNELL UNIV ITHACA NY
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| This multidisciplinary research project was concerned with the development, understanding and application of powerful techniques for the manipulation and study of spin systems, the fabrication and study of interacting spin assemblies, and the study, characterization and application of spin transfer effects and of nanomagnet dynamics excited by spin polarized currents. Major accomplishments achieved during this project include the development and application of new tools and innovative techniques for the manipulation ... |
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| The Relationship of Microscopic Material Characteristics & Physical Behavior of Quantum Dots |
25 AUG 2006 |
4 pages |
| Authors:
Shan Torng; Y-C Fang; L. Hsu; CHUNG-SHAN INST OF SCIENCE AND TECHNOLOGY TAO-YUAN (TAIWAN) MATERIAL AND ELECTRO-OPTICS DIV
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| This research collected and analyzed the composition, structure and microstructure information at microscopic scales for the self-organized InAs/GaAs quantum dots through development of proper characterization techniques. |
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| Stress-Engineered Quantum Dots for Multispectral Infra-Red Detector Arrays |
30 JUN 2006 |
9 pages |
| Authors:
A. Madhukar; A. Konkar; J. C. Campbell; Y. C. Chang; W. I. Wang; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| During the above-noted period of this Final Technical Report, the following salient milestones were reached: (1) Introduced and demonstrated the concept of injecting electrons into the quantum dot (OD) active infra-red absorbing region from bracketing doped contact layers (to suppress unwanted dark current) leaving the QD region undoped; (2) Introduced and demonstrated the benefits of the concepts of (a) strain-relieving OD capping layers, (b) current blocking layers, and (c) lateral ... |
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| Scanning Photoemission Microscopy of Photo-cathode Surfaces |
APR 2006 |
2 pages |
| Authors:
J. L. Shaw; J. E. Yater; J. E. Butler; D. W. Feldman; N. Moody; P. G. O'Shea; NAVAL RESEARCH LAB WASHINGTON DC
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| We describe a scanning photoemission microscope using a focused laser beam. We find the system can provide photoemission images with ~10 micrometers resolution. Images of Cs deposited in local areas on clean p-GaAs showed that the Cs does not move significantly even when heated to 450C. |
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| Femtosecond Laser Machining of Gallium Arsenide Wafers for the Creation of Quasi-Phasematched Devices |
21 FEB 2006 |
13 pages |
| Authors:
Derryck T. Reid; HERIOT-WATT UNIV EDINBURGH (UNITED KINGDOM)
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| This report results from a contract tasking Heriot-Watt University as follows; The project will use femtosecond laser machining to create comb-like micro-structures from GaAs wafers that can be combined to produce a suitably oriented pattern for QPM. Readily available GaAs wafers will be used and the study will concentrate on evaluating; (a) the quality of femtosecond machining possible in GaAs in terms of its repeatability precision and surface finish; (b) ... |
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| A Novel, Light Weight Solar Array: Comparison with Conventional Systems |
2006 |
6 pages |
| Authors:
Jr. Vendura George J.; Patrick Malone; Larry Crawford; L'GARDE INC TUSTIN CA
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| A novel, lightweight solar panel design is described that incorporates the best features from three separate areas of development: (1) advanced solar cells; (2) light weight, flexible blanket technology; and (3) deployment by inflation. In this study, inflation-deployed panels of various powers incorporating four different types of low mass solar cells are investigated with respect to conventional systems. Depending on panel size and cell type, five-fold and three-fold improvements in ... |
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| Envelope Switched Doherty Power Amplifier For RF Applications (Preprint) |
DEC 2005 |
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| Authors:
Jinseong Jeong; Yuanxun E. Wang; MMCOMM INC TORRANCE CA
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| This report was developed under a SBIR contract. A new concept of envelope switched Doherty amplifier is introduced. The proposed amplifier maintains maximum efficiency over a wide range of output power fluctuation. The essential idea is to drive two amplifier devices connected in Doherty configuration with a pulsed envelope signal. A high-Q, low loss filter is placed at the output to recover for linearity and to generate a time-varying equivalent ... |
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| Mid-Infrared Quantum Dot Cascade Lasers |
18 NOV 2005 |
10 pages |
| Authors:
Dennis G. Deppe; TEXAS UNIV AT AUSTIN OFFICE OF SPONSORED PROJECTS
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| This project conducts research necessary to design, growth, and demonstrate laser action in semiconductor quantum dots based on unipolar injection. The designs use new injection techniques that account for the electron wavefunction symmetries based on the height-to-base aspect ratios of self-organized quantum dots. The material systems being explored are InAs quantum dots grown within either GaAs-based or InP-based heterostructures. While GaAs-based quantum dots are better developed, InP-based quantum dots benefit ... |
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| Modeling Low Temperature C-V Profiling in Blocked Impurity Band Detectors |
SEP 2005 |
67 pages |
| Authors:
Steven J. Tschanz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Silicon Blocked Impurity Band (BIB) detectors are state-of-the-art devices to detect light in the near to mid infrared range (5-40 m). Numerical modeling of BIB detectors is performed using a four-region finite difference approach to study the role of space charge in C-V (capacitance-voltage) profiling of minority carrier doping and the role of blocking layer thickness and minority doping concentration in alternate bias operation. Compensation in the blocking layer is ... |
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| Fabrication of Tunable Quantum Well Infrared Photodetectors (QWIP), Polarization Sensitive QWIPs and Enhanced Coupling Grating Structures |
24 AUG 2005 |
21 pages |
| Authors:
Sanjay Krishna; NEW MEXICO UNIV ALBUQUERQUE CENTER FORHIGH TECHNOLOGY MATERIALS
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| This project investigates the properties of intersubband reduced dimension devices based on quantum wells and quantum dots, which could be used for infrared detection. In the past few years, there has been active research on studying the performance characteristics of mid-wave infrared (MWIR, 3-5 m) and long-wave infrared (LWIR, 8-12 m) applications. Present-day photon detectors in this wavelength range need to be cooled to liquid nitrogen temperature or below. Quantum ... |
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| Defect Engineering Through Substrate Design |
31 JUL 2005 |
21 pages |
| Authors:
Thomas F. Kuech; Susan E. Babcock; WISCONSIN UNIV-MADISON
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| A comprehensive program in the control of extended defects associated with the growth of large lattice-mismatched materials was undertaken. This program was aimed at understanding the interaction of extended defects with stress that is intentionally introduced into a substrate structure and develop processes for the growth of large lattice mismatched materials with a substantially reduced defect density over large substrate areas. The narrow band gap semiconductors, GaSb and InAs, were ... |
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| Tunable Solid-State Mid-IR Laser Engineering |
JUL 2005 |
15 pages |
| Authors:
Kenneth L. Schepler; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH SENSORS DIRECTORATE
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| This report describes in-house efforts to develop advanced tunable mid-IR laser materials and nonlinear frequency conversion techniques useful for IRCM and laser radar sources. We developed a new class of laser materials, Cr2+doped II-VI materials, with broadband tunability in the 2-3 micron region with room temperature operation and 4.2-W output. We fabricated periodically poled ferroelectric materials and demonstrated broadband tuning and narrowband seeding. We demonstrated pulse energies of 60mJ from ... |
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| Threshold Dependence on the Spectral Alignment Between the Quantum-Well Gain Peak and the Cavity Resonance in InGaAsP Photonic Crystal Lasers |
01 JUN 2005 |
4 pages |
| Authors:
J. R. Cao; Wan Kuang; Seng-Jun Choi; Po-Tsung Lee; John D. O'Brien; P. D. Dapkus; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF ELECTRICAL ENGINEERING AND ELECTROPHYSICS
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| Lithographically defined multi wavelength photonic crystal laser arrays are reported. The dependence of the threshold pump power on the spectral alignment between the quantum-well gain peak and the cavity resonance wavelength is investigated. This is done at, and slightly above, room temperature. |
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| Optimized Performance GaAs-Based Diode Lasers: Reliable 800-nm 125W Bars and 83.5% Efficient 975-nm Single Emitters |
2005 |
6 pages |
| Authors:
Paul Crump; Jun Wang; Trevor Crump; Shiguo Zhang; Mike Grimshaw; Weimin Dong; Mark DeFranza; Suhit Das; Mark DeVito; Jason Farmer; NLIGHT PHOTONICS CORP VANCOUVER WA
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| GaAs-based high power diode bars produce wavelengths in the range of 780 to 980 nm and are widely used for pumping a broad range of rare earth doped solid-state lasers. As the markets for these laser systems mature, diode lasers that operate at higher power levels, greater overall efficiency, and higher reliability are in high demand. In this paper we report efficiencies of up to 83.5% in the 9xx-nm band, ... |
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| Terahertz Radiation Emitters from Narrow-Gap Semiconductors |
2005 |
39 pages |
| Authors:
Arunas Krotkus; SEMICONDUCTOR PHYSICS INST VILNIUS (LITHUANIA)
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| This report results from a contract tasking Semiconductor Physics Institute as follows: The grantee will investigate optimizing material parameters of low-temperature grown GaAs for efficient THz emitters and detectors. |
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| Study of the Formation Mechanism of Self-Assembled Quantum Dot Arrays with a Focus on Alloying and Nucleation Control |
14 DEC 2004 |
35 pages |
| Authors:
Ya-Hong Xie; HyungJun Kim; ZuoMing Zhao; Bin Shi; Jian Liu; CALIFORNIA UNIV LOS ANGELES
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| The objective of the research project is to further the understanding of key materials science with regard to the formation mechanism of semiconductor self assembled quantum dots via epitaxy. During the funding period of 3+ years, we have made significant progress in that direction. We have conducted in-depth study on the following specific topics: the importance of alloying during epitaxial growth of SAQDs; the function of buried misfit dislocation in ... |
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| Advanced Technologies for Chemical Weapons Detection and Analysis |
17 NOV 2004 |
27 pages |
| Authors:
Alex Robinson; Doug Adkins; Patrick Lewis; David Wheeler; Ron Manginell; Shawn Dirk; Steve Howell; R. J. Simonson; SANDIA NATIONAL LABS ALBUQUERQUE NM
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| Order Lattices of Quantum Dots |
01 NOV 2004 |
83 pages |
| Authors:
James S. Speck; Pierre M. Petroff; CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS
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| This program has been focused on the development of the enabling tools for future generation optoelectronic devices. We have focused on two main areas: (i) controlled position of quantum dots - primarily in the InAs/GaAs system and (ii) development of group III-nitride quantum dots - primarily in the GaN/AIN system. |
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| Low Noise Amplifiers Based on Lattice Engineered Substrates |
01 NOV 2004 |
117 pages |
| Authors:
James S. Speck; Umesh K. Mishra; CALIFORNIA UNIV REGENTS SANTA BARBARA OFFICE OF RESEARCH
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| In this program we are developing novel strain relaxed templates for device applications including low noise amplifiers. The approach we are investigating utilizes the process of relaxation of a coherent hypercritical thickness strained semiconductor overlayer (e.g., InGaAs). In the first two years of this program, we had focused on the relaxation of a strained layer in direct contact with an oxidizing Al containing semiconductor (AlAs or AlGaAs). In the third ... |
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| High Throughput Synthesis of Terahertz Quantum Cascade Lasers |
21 OCT 2004 |
23 pages |
| Authors:
Kurt J. Linden; SPIRE CORP BEDFORD MA
|
| This Phase I STTR program (Topic #AF03T024) was aimed at the design and synthesis of an AlGaAs/ GaAs-based epitaxial layer structure for terahertz quantum cascade lasers (THz QC lasers) that can be grown by metalorganic chemical vapor deposition (MOCVD). The program succeeded in growing two different THz QC laser structures by MOCVD. The wafer growths of these 10 micron thick epitaxial structures by MOCVD required 5 hours of growth time, ... |
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| Imaging Transport: Optical Measurements of Diffusion and Drift in Semiconductor Materials and Devices |
SEP 2004 |
61 pages |
| Authors:
Will Freeman; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Knowledge of transport parameters is important to the development of new optoelectronic materials and devices, such as ultraviolet (UV) semiconductor lasers and advanced solar cells. A series of experiments was performed to measure fundamental transport parameters in luminescent semiconductor materials. Using a technique that couples a scanning electron microscope (SEM) in spot mode with a charge coupled display (CCD) camera, it is possible to image the recombination of charge created ... |
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| A Novel Approach to Modeling the Effects of Radiation in Gallium- Arsenide Solar Cells Using Silvaco's ATLAS Software |
SEP 2004 |
85 pages |
| Authors:
Aaron L. Crespin; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The effects of radiation in GaAs solar cells has been extensively researched and the results of numerous investigation have yielded a considerable amount of information about the degradation in irradiated solar cells. This thesis establishes a novel method in which to use Silvaco's physically-based device simulator, ATLAS, to model the effects of radiation on solar cell output characteristics. A virtual model representing a single junction GaAs solar cell was created ... |
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| Simulating Radiation-Induced Defects on Semiconductor Devices |
SEP 2004 |
79 pages |
| Authors:
Dewey C. Gladney; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Exploring semiconductor lifetime, reliability and performance is a never-ending science for today's modern electronics. One significant problem that affects all of these areas is radiation-induced damage. Making calculations to determine how semiconductor devices will hold up in radiation-harsh environments has to be achieved in order to determine system lifetime once placed in their operational capacity. Today's high-technology investments in such areas as satellite design, medical advances, military and commercial hardware, ... |
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| Synthesis and Characterization of Ge Nanocrystals for Thin-Film Applications |
30 JUN 2004 |
9 pages |
| Authors:
Susan M. Kauzlarich; CALIFORNIA UNIV DAVIS DEPT OF CHEMISTRY
|
| The authors have developed a new route for the synthesis of alkyl terminated Germanium (Ge) nanoparticles. These nanoparticles are stable and uniform in size. This is an important first step for determining how to prepare a Ge film from Ge nanoparticles. Preliminary TEM indicates that the melting point of the Ge nanoparticles will be significantly lower than that of the bulk (937 degrees C). Once the melting point is known, ... |
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| Advanced Thermophotovoltaic Cells Modeling, Optimized for Use in Radioisotope Thermoelectric Generators (RTGs) for Mars and Deep Space Missions |
JUN 2004 |
131 pages |
| Authors:
Bradley P. Davenport; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| To accommodate the need for power on deep space missions, satellites must carry a source capable of providing adequate power for the life of the mission. This is currently done using radioisotope thermoelectric generators (RTGs). Current RTGs consist of a heat source, Pu-238, and a thermocouple that inefficiently converts heat into electricity. To improve the overall efficiency of RTGs, a better thermoelectric converter is needed to replace the thermocouple. This ... |
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| Search for Plasma Instability Driven THz Radiation Source |
MAY 2004 |
74 pages |
| Authors:
E. Gornik; G. Strasser; M. Kast; C. Pacher; M. Coquelin; R. Zobl; TECHNISCHE UNIV WIEN (AUSTRIA) INSTITUT FUER FESTKOERPERPHYSIK
|
| A novel concept for the generation of Terahertz generation based on current driven plasma instabilities in low-dimensional semiconductor quantum structures was investigated. The design principle is the combination of a step potential quantum well with a resonant tunneling diode, grown by MBE in the AlGaAs/GaAs material system. The interplay of heavy vertical current injection into the step well region with fast carrier extraction by the RTD is intended to create ... |
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| Optical Processes in High-Q Semiconductor Microcavities |
22 MAR 2004 |
15 pages |
| Authors:
Hailin Wang; OREGON UNIV EUGENE DEPT OF PHYSICS
|
| This final progress report summarizes research efforts in two areas: cavity QED of quantum dots and electromagnetically induced transparency (EIT) in GaAs quantum wells. Cavity QED studies are based on the development of a composite nanocrystal-microsphere system, in which CdSe/ZnS core/shell nanocrystals couple to whispering gallery modes (WGMs) in a fused silica microsphere. The composite microcavity system can feature a Q-factor as high as 108 and a nanocrystal decoherence rate ... |
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| Design and Fabrication of 850 and 980 nm Vertical Cavity Surface Emitting Laser |
MAR 2004 |
22 pages |
| Authors:
N. C. Das; H. Hsen; P. Newman; M. T. Lara; W. Chang; ARMY RESEARCH LAB ADELPHI MD
|
| Vertical-cavity surface-emitting lasers (VCSEL) are the most suitable light sources for certain optoelectronic applications because of their planner nature of light emission. VCSELs on GaAs substrates were grown by the molecular beam epitaxy technique. In this report we present detailed procedures to design and fabricate 850-nm top-emitting and 980-nm bottom-emitting VCSELs. First a test structure was grown by the molecular-beam epitaxy (MBE) technique and was characterized by reflectance and photoluminescence ... |
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| Road to Intelligent Optical Devices: Instrumentation for Characterization of Optical Materials |
2004 |
5 pages |
| Authors:
Hailin Wang; Miriam Deutsch; OREGON UNIV EUGENE DEPT OF PHYSICS
|
| Equipment acquired and preliminary research results utilizing the equipment are reported. A synchronously-pumped optical parametric oscillator and a regenerative Ti:Sapphire amplifier system, both from Coherent, Inc., have been acquired and installed. The equipment has been used for optical characterization of metallo-dielectric photonic crystals (MDPCs) and for realization of electromagnetically-induced transparency (EIT) in semiconductor heterostructures. Ordered MDPCs have been successfully fabricated via colloidal assembly. EIT in semiconductors have been demonstrated for ... |
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| Manipulation and Control of Nanometer-Scale Magnetism for Multifunctional Information Processing |
2004 |
7 pages |
| Authors:
David D. Awschalom; CALIFORNIA UNIV SANTA BARBARA DEPT OF PHYSICS
|
| RESEARCH TOPICS: 1. Spontaneous Spin Polarization in Hybrid FM/ semiconductor Structures; 2. Ferromagnetic Imprinting of Nuclear Spins in Semiconductors; 3. Spatial Imaging of Magnetically Patterned Nuclear Spins in GaAs Devices; 4. Voltage Control of Nuclear Spin in Ferromagnetic Schottky Diodes; 5. Giant Planar Hall Effect in (Ga,Mn)As Lateral Devices; 6. Highly Enhanced Curie Temperature in (Ga,Mn)As Epilayers. |
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| Analysis of Stoichiometry-Related Defects in Group III - Nitrides |
31 DEC 2003 |
60 pages |
| Authors:
Eicke R. Weber; CALIFORNIA UNIV BERKELEY
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| Stoichiometry-related effects in various group III-nitrides and some GaAs-based materials were investigated. An essential part of this study were low-frequency (LF) noise analyses. The new LF-noise system, acquired with an AFOSR DURIP grant (no. F49620-01-1-0285) was set up and calibrated. LF-noise spectroscopy was then applied to GOI-based MESFETs (noise caused by excess arsenic-related defects) and AlGaN/GaN HEMTs (channel noise related to an early 2D/3D growth transition for high Al-containing AlGaN ... |
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| Voltage Tunable Two-Color Infrared Detection Using Semiconductor Superlattices |
22 DEC 2003 |
4 pages |
| Authors:
K. K. Choi; J. L. Reno; D. C. Tsui; PRINCETON UNIV NJ DEPT OF ELECTRICAL ENGINEERING
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| We demonstrate a voltage tunable two-color quantum-well infrared photodetector (QWIP) that consists of multiple periods of two distinct AlGaAs/GaAs superlattices separated by AlGaAs blocking barriers on one side and heavily doped GaAs layers on the other side. The detection peak switches from 9.5 mu m under large positive bias to 6 mu m under negative bias. The background-limited temperature is 55 K for 9.5 mu m detection and 80 K ... |
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GALLIUM ARSENIDES
