| Practical Photonic Bandgap Calculations using MPB |
22 Feb 2013 |
32 pages |
| Authors:
Douglas V Nance; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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 | This report presents a series of calculations made by using the MIT Photonic Bands computer program to resolve the band structures or dispersion relations associated with a series of 2D and 3D photonic crystal lattices. We emphasis the development of techniques for drafting code input to allow the solution of more complicated crystal lattices that may not be easily described with normal code syntax. Due attention is paid to the ... |
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| Fabrication of Cu2O/TiO2 Nanotubes Heterojunction Arrays and Investigation of Their Photoelectrochemical Behaviour |
05 Nov 2012 |
23 pages |
| Authors:
Francesco Di Quarto; Monica Santamaria; PALERMO UNIV (ITALY)
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| In the frame of the grant W911NF-11-1-0386, this 4th interim report is focused on the fabrication of Cu2O/TiO2 nanotubes heterojunction arrays to be used in photovoltaic or photoelectrochemical solar cells. The presence of Cu2O nanoparticles on the TiO2 NTs surface may overcome the low charge separation efficiency because of the superior host structure provided spatially by the TiO2 nanotubes array besides their matched energy bands. Moreover, the highly ordered nanotube ... |
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| Narrow Gap, High Mobility, and Stable Pi Conjugated Polymers |
20 Sep 2012 |
20 pages |
| Authors:
John R Reynolds; FLORIDA UNIV GAINESVILLE DEPT OF CHEMISTRY
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| High mobility and ambient stable, processable pi-conjugated and electroactive polymers for optoelectronic and redox charge storage applications were developed. Dithienogermole (DTG) was developed as a new electron donor and isoindigo (iI) as a new electron acceptor. By alternating electron donor (D) and acceptor (A) moieties, new charge transport and solar polymers have been developed. Using dithienosilole (DTS) in conjunction with benzothiadiazole (BTD) as an acceptor, field-effect hole mobilities are enhanced ... |
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| Comprehensive Study of Plasma-Wall Sheath Transport Phenomena |
10 Sep 2012 |
21 pages |
| Authors:
Mitchell L Walker; Michael Keidar; William J Ready; Julian J Rimoli; Greg Thompson; GEORGIA INST OF TECH ATLANTA SCHOOL OF AEROSPACE ENGINEERING
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| The research effort aims to determine the fundamental transport properties (mass, charge, and energy) within the plasma sheath, and determine the relationship between plasma properties and wall surface modification as a function of wall material. Investigators from the Georgia Institute of Technology (GT), University of Alabama (UA), and George Washington University (GWU) have begun a comprehensive, integrated, multidisciplinary study on the nature and transport properties of the interaction between plasma ... |
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| Graphene Research Support |
Sep 2012 |
5 pages |
| Authors:
Peter Blake; Da Jiang; Craig Lang; GRAPHENE INDUSTRIES LTD MANCHESTER (UNITED KINGDOM) MANCHESTER CENTER OF MESOSCIENCE AND NANOTECHNOLOGY
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| There was a steady increase in average flake size in the years following the initial isolation of monolayer grapheme in 2004, but even by 2008, flakes rarely exceeded 1000 sq microns. As part of the research for this grant, carefully analyzed the factors that affect flake size, including: graphite source (natural, HOPG, Kish), type of adhesive tape, number of cleaves, substrate material and roughness, substrate cleaning (sonication, piranha etch, oxygen ... |
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| Higher-Order Adaptive Finite-Element Methods for Kohn-Sham Density Functional Theory |
03 Jul 2012 |
50 pages |
| Authors:
P Motamarri; M R Nowak; K Leiter; J Knap; V Gavini; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| We present an efficient computational approach to perform real-space electronic structure calculations using an adaptive higher-order finite-element discretization of Kohn-Sham density-functional theory (DFT). To this end, we develop an a priori mesh adaption technique to construct a close to optimal finite-element discretization of the problem. We further propose an efficient solution strategy for solving the discrete eigenvalue problem by using spectral finite-elements in conjunction with Gauss-Lobatto quadrature, and a Chebyshev ... |
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| Graphene Nanowalls as Ingenious Material for Catalysts and Superconductors |
14 May 2012 |
6 pages |
| Authors:
Kuei-Hsien Chen; ACADEMIA SINICA TAIPEI (TAIWAN) INSTTITUTE OF ATOMIC AND MOLECULAR SCIENCES
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| This report describes nitrogen doping of graphene nanowalls (GNWs) via in-situ doping during CVD growth. Based on the PIs experience with nitrogen doping in carbon nanotubes (CNTs), N-doping of CNTs can be achieved to enhance deposition of Pt nanoparticles, which is effective for catalytic performance in fuel cells. He adopted a similar idea for CNTs and applied it for the growth of GNWs. The N-GNWs thus produced also showed potential ... |
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| Direct Writing of Graphene-based Nanoelectronics via Atomic Force Microscopy |
07 May 2012 |
67 pages |
| Authors:
Jr Haydell Michael W; NAVAL ACADEMY ANNAPOLIS MD
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| This project employs direct writing with an atomic force microscope (AFM) to fabricate simple graphene-based electronic components like resistors and transistors at nanometer-length scales. The goal is to explore their electrical properties for graphene-based electronics. Conducting nanoribbons of graphene were fabricated using thermochemical nanolithography (TCNL). TCNL uses a heated AFM cantilever to provide precise local heating to an insulating fluorographene (FG) substrate. The heat reduces the substrate into a material ... |
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| Device Technologies for Semiconductor Spintronic Circuits |
20 Apr 2012 |
3 pages |
| Authors:
James Kolodzey; DELAWARE UNIV NEWARK DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
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| The goal of this project was to develop spin injection and detection techniques to enable spin transport to enhance the speed and design of CMOS VLSI circuits. Progress toward this goal over the duration of the award specifically impacts: (1) Understanding extrinsic origins of spin depolarization at interfaces and with localized impurity states; and (2) Quantifying the extent to which physical processes and boundary conditions affect spin dephasing in vertical-transport ... |
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| Crossbar Nanocomputer Development |
Apr 2012 |
56 pages |
| Authors:
Nathaniel C Cady; STATE UNIV OF NEW YORK AT ALBANY COLL OF NANOSCALE SCIENCE AND ENGINEERING
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| This effort expanded development of memristive nanoelectronic junction materials for high density memory and advanced logic applications. The focus of the effort was to develop metal oxide materials for resistive memory devices (RMDs), which are also known as memristors or resistive random access memory (Re-RAM or RRAM). The major goal was to fabricate such devices in a crossbar configuration (overlapping metal lines which create multiple junctions in an array format) ... |
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| Drop Tower Characterization of Army Research Lab (ARL)-Fabricated Thin-Film Lead Zirconate Titanate (PZT) Transducers |
Apr 2012 |
96 pages |
| Authors:
Tracy D Hudson; Stephen G Cruit; Michael Allen; ARMY AVIATION AND MISSILE RESEARCH DEVELOPMENT AND ENG CTR REDSTONE ARSENAL AL WEAPONS SCIENCES DIRECTORATE
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| The report documents the characterization of the impulse response of piezoelectric thin-film transducers to low-impacts provided by a ball-drop apparatus and the effects of device size and annealing process on the impulse response. The specific piezoelectric thin-film transducers are 1-micron thick Lead Zirconate Titanate (PZT) films, as deposited by Army Research Laboratory's (ARL's) Sensors and Electronics Devices Directorate in support of Army Technology Objective Sensor, Warhead, and Fuzing Technology Integrated ... |
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| Thermal Sciences |
08 Mar 2012 |
22 pages |
| Authors:
Joan Fuller; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
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| Development of Direct Band Gap Group IV Semiconductors with the Incorporation of Sn |
Mar 2012 |
7 pages |
| Authors:
Hung Hsiang Cheng; NATIONAL TAIWAN UNIV TAIPEI CENTER FOR CONDENSED MATTER SCIENCES
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| Due to the indirect energy band of group IV materials of Si and Ge, these materials and their alloys can't be used to make optical devices. In this project, direct bandgap group IV alloy of GeSn alloy was developed. This report covers: (a) growth techniques of GeSn alloy with various Sn compositions, (b) characterization of the alloy, and (c) physical properties of the alloy and identification of direct optical transitions. ... |
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| Nonlinear Dynamics and Quantum Transport in Small Systems |
22 Feb 2012 |
10 pages |
| Authors:
Ying-Cheng Lai; ARIZONA STATE UNIV TEMPE
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| MEMS/NEMS are characterized by their small size, low power consumption, and ultra fast speed. There is a growing interest in the fundamental dynamics of MEMS/NEMS and their potential applications including future military systems. To understand and generate various nonlinear dynamical phenomena including chaos in MEMS/NEMS can thus be of great interest from the standpoint of defense. During the project period, we first focused on understanding the dynamical mechanism of intrinsic ... |
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| Evaluating Superconducting YBCO Film Properties Using X-Ray Photoelectron Spectroscopy (Postprint) |
Feb 2012 |
11 pages |
| Authors:
Paul N Barnes; Justin C Tolliver; Timothy J Haugan; Sharmila M Mukhopadhyay; John T Grant; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH
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| Initial results have been recently reported that suggest a potential correlation exists between the full-width-half-maximum (FWHM) of the Y(3d) peak obtained by x-ray photoelectron spectroscopy (XPS) and the critical current density a YBa2Cu3O7-x film can carry. In particular, the Y(3d5/2) demonstrated a stronger correlation. Transport currents were determined by the 4-point contact method using the 1?V/cm criterion. An apparent correlation was also suggested between the Y(3d) FWHM and ac loss ... |
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| Flux Pinning Effects of Y2O3 Nanoparticulate Dispersions in Multilayered YBCO Thin Films |
Feb 2012 |
10 pages |
| Authors:
T A Campbell; T J Haugan; P N Barnes; I Maartense; J Murphy; L Brunke; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH
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| The flux pinning effects of Y2O3 nanoparticulate inclusions in YBa2Cu3O7-delta (Y123 or YBCO) thin films using (Y2O3/Y123) x N multilayer structures were studied. The multilayer films were made with pulsed laser deposition (PLD) on SrTiO3 and LaAlO3 substrates with a Y2O3 nanoparticulate 'pseudo-layer' thickness ranging from 0.2 to 1.4 nm, and YBCO layer thickness varying from 7 to 50 nm. Scanning electron microscopy images showed well-defined nanoparticle formation on film ... |
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| Growth Optimization of YBa2NbO6 Buffer Layers (Postprint) |
Feb 2012 |
5 pages |
| Authors:
N A Yust; T J Haugan; J C Tolliver; P N Barnes; S Sathiraju; R N Nekkanti; I Maartense; T L Campbell A L; Q X Jia; P N Arendt; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH
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| The growth optimization of YBa2NbO6 (YBNO) buffer layers on LaAlO3 (100), MgO (100) single crystals, and IBAD MgO buffered Inconel substrates has been investigated. X-ray diffraction confirms the epitaxial growth of highly h00 oriented YBNO thin films on single crystal substrates and IBAD MgO buffered Inconel substrates. The best average surface roughness of the YBNO films deposited on buffered substrates is 2 nm. The critical temperature (Tc) of YBa2Cu3O7-x (Y-123) ... |
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| YBa2Cu3O7-d Films with a Nanoparticulate Dispersion of Y2BaCuO5 for Enhanced Flux Pinning (Preprint) |
Feb 2012 |
6 pages |
| Authors:
Paul N Barnes; Timothy J Haugan; Srinivas Sathiraju; Julianna M Evans; Justin C Tolliver; Michael D Sumption; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH
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| A comparison study of YBa2Cu3O7-x (Y123) films incorporating a nano-particulate dispersion of second-phase Y2BaCuO5 (Y211) and Y123 films incorporating a material (X, not specified) more closely lattice matched with Y123 is given. The inclusion of the nano-particulate dispersion was for the purpose of increasing superconducting film's magnetic pinning strength with the resultant improved in-field critical current density. The Y211 particulate and X layered inclusions in the Y123 was accomplished with ... |
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| Growth of YBCO Thin Films on TiN(001) and CeO2-Coated TiN Surfaces |
Feb 2012 |
10 pages |
| Authors:
Paul N Barnes; Rand Biggers; Gregory Kozlowski; Chakrapani Varanasi; Iman Maartens; Rama Nekkanti; Tim Peterson; Timothy J Haugan; Ilwon Kim; Scott A Barnett; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH
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| Epitaxial growth of YBa2Cu3O7-x (YBCO) layers on TiN(0 0 1) surfaces was explored, both with and without CeO2 intermediate layers. The epitaxial TiN layers were grown on MgO(0 0 1) and textured Ni substrates. Thin CeO2 (200 nm thick) and YBCO (300 nm thick) layers were grown on TiN-coated MgO substrates, using pulsed laser deposition. While YBCO grown directly on TiN was of poor quality, a good epitaxial YBCO layer ... |
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| In Situ Creation of Nanoparticles from YBCO by Pulsed Laser Deposition (Postprint) |
Feb 2012 |
9 pages |
| Authors:
Paul N Barnes; Timothy J Haugan; P T Murray; Richard Rogow; Glen P Perram; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIR/POWER DIV/MECHANICAL ENERGY CONVERSION BRANCH
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| Nanoparticles created by the laser ablation of YBCO are reported. The experimental procedure entailed pulsed laser deposition (PLD) of YBCO at a high background pressure of 5 Torr O2. The sizes of the nanoparticles range from 3 to 5 nm and are typical of the depositions made using laser energies of 50 mJ per pulse. Optical emission spectroscopy was used to characterize the PLD plume. Under nanoparticle deposition conditions, the ... |
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| Impact of Edge-Barrier Pinning in Superconducting Thin Films (Postprint) |
Feb 2012 |
5 pages |
| Authors:
W A Jones; M J Mullins; P N Barnes; T J Haugan; F J Baca; R L Emergo; J Wu; J R Clem; DAYTON UNIV OH
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| It has been suggested that edge-barrier pinning might cause the critical current density (Jc) in bridged superconducting films to increase. Subsequent work indicated that this edge-barrier effect does not impact bridges larger than 1 micrometers. However, we provide a theoretical assessment with supporting experimental data suggesting edge-barrier pinning can significantly enhance Jc for bridges of a few microns or even tens of microns thus skewing any comparisons among institutions. As ... |
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| Towards Graphene-Based Electronics |
28 Jan 2012 |
6 pages |
| Authors:
Andre Geim; Kostya Novoselov; MANCHESTER UNIV (UNITED KINGDOM)
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| During the last year, we have published more than 20 research papers including 2 Science papers, 4 papers in Nature Physics and Nature Communications and 5 Phys. Rev. Letters. The most important technological result probably was the development of fabrication procedures to encapsulate graphene between boron-nitride crystals, which allows us to routinely achieve mobilities above 100,000 cm2/Vs and demonstrate room-temperature ballistic transport at micron scale (Nano Lett. 11, 2396, 2011). ... |
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| HVPE InGaN for LEDs- State of the Art and Horizons |
19 Jan 2012 |
5 pages |
| Authors:
Alexander Syrkin; TECHNOLOGIES AND DEVICES INTERNATIONAL INC SILVER SPRING MD
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| We grew unintentionally doped n-type InGaN layers in the temperature range from 600 to 750 deg C; using GaCl3, InCl3, and NH3 as gas sources; and argon as carrier gas. The InN content in the layers varied from 5 to 50 mole % depending on the growth conditions. Growth was performed on undoped n-GaN/sapphire films with a thickness of 2 to 20 microns, and on Mg-doped p-GaN/sapphire template with a ... |
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| Center of Excellence for Battlefield Capability Enhancements: Envronmentally Stable Flexible Displays |
18 Jan 2012 |
121 pages |
| Authors:
Shanthi Iyer; Jay Lewis; NORTH CAROLINA AGRICULTURAL AND TECHNICAL STATE UNIV GREENSBORO OFFICE OF SPONSORED PROGRAMS
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| The focus of the Center is to develop and demonstrate novel materials, both for device structures that advance the state-of-the-art in flexible electronics, as well as for environmentally-stable, hybrid, organic/inorganic semiconductors, leading to robust luminescent devices for flexible displays for the U.S. soldier. Performance of transparent and conducting oxides of indium tin oxide and F-doped ZnO films on plastics and their stability under mechanical deformation were investigated. Thin film transistors ... |
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| Wide Bandgap Semiconductor Nanowires for Electronic, Photonic and Sensing Devices |
05 Jan 2012 |
7 pages |
| Authors:
S Pearton; FLORIDA UNIV GAINESVILLE OFFICE OF RESEARCH
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| We synthesized a variety of wide bandgap nanowires using GaN and ZnO and made functional devices from them for sensing, electronics and photonics.These included a very sensitive glucose sensor and hydrogen sensors with ppm sensitivity at room temperature. We also developed amorphous InZnO for transparent TFTs and showed highly stable operation.This effort grew out of the work on ZnO nanowires,where we noticed severe segregation effects when we tried to grow ... |
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| High-Frequency, 6.2 Angstrom pN Heterojunction Diodes |
Jan 2012 |
5 pages |
| Authors:
James G Champlain; Richard Magno; Doewon Park; Harvey S Newman; J B Boos; NAVAL RESEARCH LAB WASHINGTON DC ELECTRONICS SCIENCE AND TECHNOLOGY DIV
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| Sb-based pN heterojunction diodes at 6.2 Angstroms consisting of narrow bandgap p-type In0.27Ga0.73Sb and wide bandgap n-type In0.69Al0.41As0.41Sb0.59, have been fabricated and measured. These diodes show excellent electrical characteristics with an ideality factor of 1.2 and high current density. S-parameter measurements and subsequent analysis show that these diodes have RC-cutoff frequencies over 1 THz, making these diodes excellent choices for high-frequency applications, such as sub-harmonic mixers for frequency conversion. |
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| Proof-of-Concept: Assembling Carbon Nanocrystals for Ordered 3D Network |
13 Dec 2011 |
19 pages |
| Authors:
Shiren Wang; TEXAS TECH UNIV LUBBOCK
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| In this work, we developed a simple process to assemble a 3D ordered network consisting of alternative stacks of vertically aligned carbon nanotubes array and horizontally aligned graphene sheets. The interface between carbon nanotube and graphene sheets was tailored by an ultra-thin binder material and process parameters. The experimental results indicated that a 150nm-thickness binder was preferred for the successful assembly due to the difficulty in the control of binder ... |
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| High Transition Temperature Quantum Interference Filters |
28 Nov 2011 |
3 pages |
| Authors:
Shane A Cybart; R C Dynes; CALIFORNIA UNIV BERKELEY DEPT OF PHYSICS
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| We have fabricated and tested large scale arrays of Josephson junctions. Some devices have as many as 150,000 junctions in a single device. To aid in device design we have also developed a numerical simulation program in Matlab to simulate voltage magnetic field characteristics for these arrays. Our numerical simulation code supports the modeling of 2 dimensional array structures and takes into account mutual interactions between all of the squids ... |
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| Thermal Transport in 1-D and 2-D Nanostructures |
08 Nov 2011 |
6 pages |
| Authors:
Mandar M Deshmukh; TATA INST OF FUNDAMENTAL RESEARCH BOMBAY (INDIA)
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| We have measured the thermal conductivity of individual nanowires with engineered defects. The key emphasis is on studying how the phonon spectrum can be modified using defect engineering in 1D and 2D systems. Our work with nanowires suggests that strong localization of phonons is possible due to twin defects oriented perpendicular to the axis of nanowires. This results in the reduction of measured thermal conductivity by three orders of magnitude. ... |
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| Dislocation Decorrelation and Relationship to Deformation Microtwins during Creep of a Gamma' Precipitate Strengthened Ni-based Superalloy |
Nov 2011 |
17 pages |
| Authors:
R R Unocic; N Zhou; L Kovarik; C Shen; Y Wang; M J Mills; OAK RIDGE NATIONAL LAB TN MATERIALS SCIENCE AND TECHNOLOGY DIV
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| The evolution of microtwins during high temperature creep deformation in a gamma' strengthened Ni-based superalloy has been investigated through a combination of creep testing, transmission electron microscopy (TEM), theoretical modeling, and computer simulation. Experimentally, microtwin nucleation sources were identified and their evolution was tracked by characterizing the deformation substructure at different stages of creep deformation. Deformation is highly localized around stress concentrators such as carbides, borides and serrated grain boundaries, ... |
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| Optimization of the Al2O3/GaSb Interface and a High-Mobility GaSb pMOSFET |
Oct 2011 |
10 pages |
| Authors:
Aneesh Nainani; Toshifumi Irisawa; Ze Yuan; Brian R Bennett; J B Boos; Yoshio Nishi; Krishna C Saraswat; STANFORD UNIV CA DEPT OF ELECTRICAL ENGINEERING
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| While there have been many demonstrations on n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) in III-V semiconductors showing excellent electron mobility and high drive currents, hole mobility in III-V p-channel MOSFETs (pMOSFETs) has traditionally lagged in comparison to silicon. GaSb is an attractive candidate for high-performance III-V pMOSFETs due to its high bulk hole mobility. We fabricate and study GaSb pMOSFETs with an atomic layer deposition Al2O3 gate dielectric and a self-aligned ... |
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| First-Principles Determination of Thermal Properties in Nano-Structured Hexagonal Solids with Doping Modifications for Thermal Energy Harvesting |
20 Sep 2011 |
5 pages |
| Authors:
Umesh Waghmare; JAWAHARLAL NEHRU CENTRE FOR ADVANCED SCIENTIFIC RESEARCH BANGALORE (INDIA)
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| Using the Quasi-continuum model of grapheme developed in the first phase of the work, we estimated thermal conductivity of graphene with relaxation associated with scattering of phonons by topological Stone-Wales defects. Work is in progress to estimate thermal conductivity using Kubo-Greenwood formula as well as the Fermi golden rule-based phenomenological approach. These three approaches will help in understanding thermal transport properties of graphene at a basic level. |
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| The Effects of Rare Earth Doping on Gallium Nitride Thin Films |
Sep 2011 |
182 pages |
| Authors:
Stephen R McHale; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| The thermal neutron capture cross section of the rare earth (RE) metal isotope Gd-157 is the largest of all known natural elements, which distinguishes the material as a logical candidate for neutron detection. To address an incomplete understanding of rare earth doped Gallium Nitride (GaN) materials, investigations of the surface electronic structure and interface properties of GaN thin films doped with rare earths (Yb, Er, Gd) were undertaken. Lattice ion ... |
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| A Double-Well System Composed of Phonons in a Pair of Trapped Ions |
Sep 2011 |
12 pages |
| Authors:
Patricia J Lee; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| This report presents a theoretical framework using a double-well system to describe the transverse phonon coupling between a pair of trapped ions. The double-well system is a special case of the more generalized Bose-Hubbard Model, with exactly two sites available to store particles. Analogous double-well systems in solid-state junctions and in Bose-Einstein condensates have been used for interferometric sensing, as well as quantum information processing, and many exotic quantum phenomena ... |
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| Using a Volume Bragg Grating Instead of a Faraday Isolator in Lasers Incorporating Stimulated Brillouin Scattering Wavefront Reversal or Beam Cleanup |
29 Aug 2011 |
6 pages |
| Authors:
John E McElhenny; Jeffrey O White; Steven D Rogers; Tigran Sanamyan; Leonid B Glebov; Oleksiy Mokhun; Vadim I Smirnov; ARMY RESEARCH LAB ADELPHI MD
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| A master-oscillator power-amplifier with stimulated Brillouin scattering (SBS) beam cleanup or wavefront reversal typically incorporates a Faraday isolator to outcouple the Stokes light, limiting the power scalability. Volume Bragg gratings (VBGs) have the potential for scaling to higher powers. We report here the results of tests on a VBG designed to resolve wavelengths 0.060 nm apart, corresponding to the 16 GHz frequency shift for SBS backscattering at 1064 nm in ... |
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| Realization and Integration of Large Lattice Mismatched Materials for Device Innovation: A Comprehensive Approach to the Underlying Science and Practical Application |
08 Jul 2011 |
15 pages |
| Authors:
Thomas F Kuech; Luke Mawst; Susan E Babcock; S S Lau; A S Brown; N M Jokerst; T S Kuan; WISCONSIN UNIV MADISON
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| Critical DoD need for advanced, high performance, multi-functional devices and circuits is addressed in this work. The underlying technology need is materials integration: the monolithic or polylithic assembly of functional materials and devices and the generation of device structures for which no lattice-matched substrate exists. A comprehensive program in the growth, integration, and device fabrication of large lattice mismatched materials is being carried out. Both new approaches to the engineered ... |
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| InxGa1-xSb Channel p-Metal-Oxide-Semiconductor Field Effect Transistors: Effect of Strain and Heterostructure Design |
06 Jul 2011 |
10 pages |
| Authors:
Aneesh Nainani; Ze Yuan; Tejas Krishnamohan; Brian R Bennett; J B Boos; Matthew Reason; Mario G Ancona; Yoshio Nishi; Krishna C Saraswat; NAVAL RESEARCH LAB WASHINGTON DC ELECTRONICS SCIENCE AND TECHNOLOGY DIV
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| InxGa1-xSb is an attractive candidate for high performance III-V p-metal-oxide-semiconductor field effect transistors (pMOSFETs) due to its high bulk hole mobility that can be further enhanced with the use of strain. We fabricate and study InxGa1-xSb-channel pMOSFETs with atomic layer deposition Al2O3 dielectric and self-aligned source/drain formed by ion implantation. The effects of strain and heterostructure design for enhancing transistor performance are studied systematically. Different amounts of biaxial compression are ... |
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| Boron Nitride Substrates for High Mobility Chemical Vapor Deposited Graphene |
13 Jun 2011 |
4 pages |
| Authors:
W Gannett; W Regan; K Watanabe; T Taniguchi; M F Crommie; A Zettl; CALIFORNIA UNIV BERKELEY DEPT OF PHYSICS
|
| Chemical vapor deposited (CVD) graphene is often presented as a scalable solution to graphene device fabrication, but to date such graphene has exhibited lower mobility than that produced by exfoliation. Using a boron nitride underlayer, we achieve mobilities as high as 37 000 cm(expn 20)/ V s, an order of magnitude higher than commonly reported for CVD graphene and better than most exfoliated graphene. This result demonstrates that the barrier ... |
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| Complimentary Metal Oxide Semiconductor (CMOS)-Memristor Hybrid Nanoelectronics |
Jun 2011 |
15 pages |
| Authors:
Wei Wang; STATE UNIV OF NEW YORK AT ALBANY COLL OF NANOSCALE SCIENCE AND ENGINEERING
|
| The goal of this project was to explore CMOS-memristor hybrid nanoelectronic circuits for memory, FPGA, DSP, analog, and neuromorphic applications. The specific tasks of the project included: material selection, integration flow development, circuit design and simulation, and development of demonstration vehicle fabrication and testing. The major accomplishments of this effort were, 1) a Verilog-A model of a memristor and co-simulation with SPICE for one transistor one memristor (1T1R) circuits/memory cell, ... |
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| Theory and Device Modeling for Nano-Structured Transistor Channels |
JUN 2011 |
28 pages |
| Authors:
Isaiah P. Steinke; P. P. Ruden; MINNESOTA UNIV MINNEAPOLIS DEPT OF ELECTRICAL ENGINEERING
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| We have developed two models to describe the behavior of field-effect transistors with nano-structured channels. The primary factor that limits the performance of the transistor is the presence of grain boundaries. In our macroscopic model, we have explicitly modified the field-effect mobility to include terms that are dependent upon both the local carrier concentration and longitudinal field. In our mesoscopic model, we more closely look at the role of the ... |
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| Antimonide-based pN Terahertz Mixer Diodes |
Jun 2011 |
6 pages |
| Authors:
R Magno; J G Champlain; H S Newman; D Park; NAVAL RESEARCH LAB WASHINGTON DC
|
| High frequency pN heterojunction diodes with cutoff frequencies over 1 THz have been fabricated using narrow bandgap high-mobility semiconductors. The pN heterojunction is composed of a 30 nm thick p-type In0.27Ga0.73Sb alloy and a 130 nm thick In0.69Al0.31As0.41Sb0.59 n-layer. A high-mobility n-type InAs0.66Sb0.34 contact layer is used to connect the mesa diode to a metal Ohmic contact. These alloys have a lattice constant a0=6.2 Angstroms and are grown on semi-insulating ... |
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| Silicon Nanotips and Related Nano-Systems Involving Fluid and Carrier Transport and Their Micro-Devices for Power and Sensing Applications |
10 May 2011 |
9 pages |
| Authors:
Li-Chyong Chen; Kuei-Hsien Chen; NATIONAL TAIWAN UNIV TAIPEI
|
| A number of micro-/nano-devices using arrayed silicon nanotips (SiNTs), ZnO nanorods and related advanced nano-composites as their key components have been developed. These devices possess specific attributes such as architecture- and/or surface/interfacecontrolled properties. For any targeted functionality, different treatments for the surface or interface are required for best optimizing the resultant physical/chemical properties. On-chip approach to fabricate micro-/nano-fluidic devices involving fluid and carrier transport, such as the electrochemical power and ... |
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| Local Electronic Properties of Graphene on a BN Substrate via Scanning Tunneling Microscopy |
09 May 2011 |
6 pages |
| Authors:
Regis Decker; Yang Wang; Victor W Brar; William Regan; Hsin-Zon Tsai; Qiong Wu; William Gannett; Alex Zettl; Michael F Crommie; CALIFORNIA UNIV BERKELEY DEPT OF PHYSICS
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| The use of boron nitride (BN) as a substrate for graphene nanodevices has attracted much interest since the recent report that BN greatly improves the mobility of charge carriers in graphene compared to standard SiO2 substrates. We have explored the local microscopic properties of graphene on a BN substrate using scanning tunneling microscopy. We find that BN substrates result in extraordinarily flat graphene layers that display microscopic Moir e patterns ... |
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| Tunable PhoXonic Band Gap Materials from Self-Assembly of Block Copoliymers and Colloidal Nanocrystals (NBIT Phase II) |
06 May 2011 |
14 pages |
| Authors:
Edwin Thomas; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| This collaborative Korea-USA proposal aims to design and fabricate tunable phoxonic band gap materials by self-assembly of block copolymer and/or colloidal crystals, characterize the resultant structures and finally measure and model/simulate their novel properties defined by their interaction with photons and phonons. Concerning this, we seek to develop methods and understanding to create both periodically structured materials (Bragg gap materials) and non-periodically structured materials (resonance gap materials). For that, self-assembly ... |
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| High Performance Organic Transistors: Percolating Arrays of Nanotubes Functionalized with an Electron Deficient Olefin |
03 Apr 2011 |
7 pages |
| Authors:
George G Malliaras; Graciela B Blanchet; Mandakini Kanungo; CORNELL UNIV ITHACA NY OFFICE OF SPONSORED PROGRAMS
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| Precise control over the electronic properties of the carbon nanotubes is key to their practical application in plastic electronics. In the present work, we have extended carbon nanotube functionalization via a 2-2 cycloaddition to electron withdrawing non-fluorinated olefins as well. Our results show that this is a fairly general approach, independent of specifics of the addend, to converting the grown mixture of metal and semiconductor tubes into high mobility semiconducting ... |
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| Silicon-nanocrystal Optoelectronic Kerr Effect for Complementary Metal-oxide Semiconductor (CMOS) Compatible Optical Switching |
APR 2011 |
18 pages |
| Authors:
Neal K. Bambba; Justin R. Bickford; Stefan F. Preble; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| There is a broad Army need to quickly transfer large amounts of data from sensors to processors on a wide variety of systems. Complementary metal-oxide semiconductor (CMOS) compatible optical intra-chip data communication systems would enable this data flow by increasing data rates and reducing circuit size and power. We investigated the fabrication of a monolithic CMOS-compatible optoelectronic silicon (Si) modulator for intra-chip communication. The modulator is designed to take advantage ... |
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| Characterization of a Boron Carbide Heterojunction Neutron Detector |
24 Mar 2011 |
193 pages |
| Authors:
James E Bevins; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| New methods for neutron detection have become an important area of research in support of national security objectives. In support of this effort, p-type B(sub 5)C on n-type Si heterojunction diodes have been built and tested. This research sought to optimize the boron carbide (BC) diode by coupling the nuclear physics modeling capability of GEANT4 and TRIM with the semiconductor device simulation tools. Through an iterative modeling process of controllable ... |
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| Graphene Nanowalls as Ingenious Material for Catalysts and Superconductors |
12 Mar 2011 |
8 pages |
| Authors:
Kuei-Hsien Chen; ACADEMIA SINICA TAIPEI (TAIWAN) INSTTITUTE OF ATOMIC AND MOLECULAR SCIENCES
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| This is the report of a preliminary study to prepare and characterize graphene via chemical vapor deposition for large area transferrable graphene, and microwave plasma-enhanced chemical vapor deposition for graphene nanowalls. |
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| Microstructure Instability in Cryogenically-Deformed Copper (Preprint) |
MAR 2011 |
12 pages |
| Authors:
S. L. Semiatin; T. Konkova; S. Mironov; A. Korznikov; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIR METALS CERAMICS AND NONDESTRUCTIVE EVALUATION DIV/METALS BRANCH
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| There is considerable interest in the potential use of cryogenic deformation for the production of nanocrystalline materials. It is believed that low homologous temperatures may suppress dynamic recovery and stimulate mechanical twinning, thus enhancing the refinement of grain size. The subsequent ambient-temperature stability of the microstructures thus produced is an important consideration with regard to practical use of such processing approaches. For example, primary recrystallization during static storage at room ... |
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| Imaging Electron Interferometer |
16 FEB 2011 |
10 pages |
| Authors:
Robert M. Westervelt; HARVARD UNIV BOSTON MA
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| The research supported by this grant is aimed at imaging the flow of electron waves through a two dimensional electron gas (2DEG) to understand both the fundamental quantum behavior that appears in semiconductor nanostructures at low temperatures, and to study the propagation of electron waves through semiconductor structures with interesting geometries. A custom-made liquid He cooled scanning probe microscope (SPM) was developed in Westervelt's group to carry out the measurements. ... |
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Solid State Physics
