| Development of Metal Cluster-Based Energetic Materials at NSWC-IHD |
Jan 2011 |
6 pages |
| Authors:
James M Lightstone; Chad Stoltz; Rebecca M Wilson; Jillian M Horn; Joe Hooper; D Mayo; B Eichhorn; K Bowen; M G White; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | Current research efforts at NSWC-IHD are utilizing gas-phase molecular beam studies theoretical calculations, and condensed-phase production methods to identify novel metal cluster systems in which passivated metal clusters make up the subunit of a molecular metal-based energetic material. The reactivity of NixAly + clusters with nitromethane was investigated using a gas-phase molecular beam system. Results indicate that nitromethane is highly reactive toward the NixAly + clusters and suggests it would ... |
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| Low Temperature Noise Measurement of an InAs/GaSb-based nBn MWIR Detector |
Jan 2011 |
9 pages |
| Authors:
Vincent M Cowan; Christian P Morath; Stephen Myers; Nutan Gautam; Sanjay Krishna; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| Recent experiments on conventional p-on-n and n-on-p Type II superlattices (SLS) infrared detectors still indicate larger than theoretically predicted dark current densities, despite the well known suppression of the Auger recombination mechanism. Rather, dark current in SLS is thought to still be limited by trap-assisted tunneling in the depletion region and surface leakage currents resulting from lack of fully passivated mesa sidewalls. An emerging infrared detector technology utilizing a unipolar, ... |
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| Multispectroscopic (FTIR, XPS, and TOFMS-TPD) Investigation of the Core-Shell Bonding in Sonochemically-Prepared Aluminum Nanoparticles Capped with Oleic Acid (Preprint) |
APR 2010 |
19 pages |
| Authors:
Andrew T. Rosenberger; Donald K. Phelps; Jonathon E. Spowart; Christopher E. Bunker; William K. Lewis; Christopher A. Crouse; Barbara A. Harruff; K. A. Fernando; Marcus J. Smith; Elena A. Guliants; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| Organically-capped metal nanoparticles are an attractive alternative to more conventional oxide-passivated materials, due to the lower reaction temperatures and the possibility of tuning the organic coating. Sonochemical methods have been used to produce air-stable aluminum nanoparticles capped with oleic acid. In order to understand the nature of the metal-organic bonding in this system, we have used FTIR, XPS, and TOFMS-TPD techniques to study the organic passivation layer and its desorption ... |
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| The Effects of Temperature and Electron Radiation on the Electrical Properties of AlGaN/GaN Heterostructure Field Effect Transistors |
Mar-2009 |
120 pages |
| Authors:
Jeffrey T Moran; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| AlGaN/GaN Heterostructure Field Effect Transistors (HFETs) have come under increased study, in recent years, owing to their highly desirable material and electrical properties, ruggedness, and survivability even during and after exposure to extreme temperature and radiation environments. These devices or similar devices constructed of AlGaN and/or GaN materials are being researched for their potential applications in many military and space based systems. In this study, unpassivated and SiN passivated Al(0.27)Ga(0.73)N/GaN ... |
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| Development of Passivation Technology for Improved GaN/AlGaN HEMT Performance and Reliability |
SEP 2005 |
80 pages |
| Authors:
C. R. Abernathy; Angela Hunter-Edwards; FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| Under the support of this contract, we have been successful in mitigating the current collapse that is found in nitride based high electron mobility transistors (HEMTs) that is responsible for low power performance from these devices. We have successfully and repeatedly grown oxide material that, along with surface cleaning recipes, reduce the surface states and reduce the device-device surface leakage. As part of the recipe development we have studied fundamental ... |
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| Investigation of Local Hydrogen Uptake in Rescaled Model Occluded Sites Using Crevice Scaling Laws |
APR 2005 |
46 pages |
| Authors:
John R. Scully; Michael Switzer; VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| The effects of occluded site geometry and applied potential on hydrogen production and uptake in a martensitic stainless steel (Fe-l3Cr-8Ni-2Mo-1Al) were explored. On planar electrode surfaces, the total hydrogen concentration was found to increase exponentially with hydrogen overpotential. The x(exp 2)/gap scaling law, where x is the pit/crevice depth and "gap" is the pit/crevice width, was utilized to rescale model pits from micrometer to millimeter dimensions. Such rescaling enabled local ... |
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| Quantification of Discrete Oxide and Sulfur Layers on Sulfur-Passivated InAs by XPS |
2005 |
11 pages |
| Authors:
D. Y. Petrovykh; J. M. Sullivan; L. J. Whitman; MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS
|
| The initial quality and stability in air of InAs(001) surfaces passivated by a weakly-basic solution of thioacetamide (CH3CSNH2) is examined by XPS. The S-passivated InAs(001) surface can be modeled as a sulfur-indium-arsenic layer-cake structure, such that characterization requires quantification of both arsenic oxide and sulfur layers that are at most a few monolayers thick. This thickness range complicates the quantitative analysis because neither standard submonolayer nor thick-film models are applicable. ... |
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| Properties and Improved Space Survivability of POSS (Polyhedral Oligomeric Silsesquioxane) Polyimides |
NOV 2004 |
14 pages |
| Authors:
Sandra J. Tomczak; Darrell Marchant; Steve Svejda; Timothy K. Minton; Amy L. Brunsvold; Eitan Grossman; George C. Schatz; Diego Troya; LiPeng Sun; Irina Gouzman; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| Kapton polyimide (PI) is widely used on the exterior of spacecraft as a thermal insulator. Atomic oxygen (AO) in lower earth orbit (LEO) causes severe degradation in Kapton resulting in reduced spacecraft lifetimes. One solution is to coat the polymer surface with SiO2 since this coating is known to impart remarkable oxidation resistance. Imperfections in the SiO2 application process and micrometeoroid/debris impact in orbit damage the SiO2 coating, leading to ... |
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| Constructive Nonlinear Control |
30 SEP 2003 |
9 pages |
| Authors:
Petar V. Kokotovic; CALIFORNIA UNIV SANTA BARBARA CENTER FOR CONTROL ENGINEERING AND COMPUTATION
|
| During this grant period, we have enhanced robustness of our designs and thus increased their ability to accommodate disturbances and unmodeled dynamics. We have also broadened the class of systems to which these methods are applicable. In a different direction, we have developed structure specific methods to analyze boundedness properties of systems with "stiffening" nonlinearities, as in micro-electromechanical probes. A major advance has been made on difficult output feedback problem ... |
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| Sub 0.1 Micrometer Asymmetric Gamma-Gate PHEMT Process Using Electron Beam Lithography |
03 APR 2003 |
6 pages |
| Authors:
W. S. Sul; D. H. Shin; J. K. Rhee; DONGGUK UNIV SEOUL (REPUBLIC OF KOREA)MILLIMETER-WAVE INNOVATION TECHNOLOGYRESEARCH CENTER
|
| In this paper, we have studied on the fabrication of GaAs-based pseudomorphic high electron mobility transistors (PHEMT's) for the purpose of millimeter-wave applications. To fabricate the high performance GaAs-based PHEMT's, we have developed unit processes, such as 0.1 micrometer GAMMA-gate lithography, silicon nitride passivation, and air-bridge process to achieve high performance of device characteristics. The DC characteristics of the fabricated PHEMT was measured at a unit gate width of 70 ... |
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| Silicon Etching in LAPPS |
14 MAR 2003 |
32 pages |
| Authors:
D. Leonhardt; S. G. Walton; D. D. Blackwell; R. F. Fernsler; R. A. Meger; NAVAL RESEARCH LAB WASHINGTON DC
|
| Initial tests using LAPPS to etch silicon with sulfur hexafluoride- containing plasmas were carried out. Material removal rates and anisotropy were determined with respect to gas composition and substrate RF-induced self-bias level. At room temperature, the removal rate increased linearly with substrate bias. Mixtures of argon and sulfur hexalluoride etched approximately ten times faster (5000 A/min) than similar mixtures of oxygenisulfur hexalluoride (^500 A/ min), with the difference being attributed ... |
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| Self-Assembled Monolayers at the Lithium Electrode/Polymer Electrolyte Interface |
21 JUN 2002 |
75 pages |
| Authors:
Dale Teeters; TULSA UNIV OK
|
| The proposed work involved the placement of self-assembled monolayers (SAMs) on the polymer electrolyte surface to deter and/or stabilize the formation of the passivation layer between the polymer electrolyte and the lithium electrode. This work combines two very scientifically and technologically important areas, lithium polymer batteries and self-assembled monolayers, resulting in a novel study that has advanced the basic understanding of the electrode/electrolyte interface and the development of better battery ... |
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| Development of GaN Mosfets and Misfets |
30 MAR 2002 |
24 pages |
| Authors:
Cammy R. Abernathy; FLORIDA UNIV GAINESVILLE
|
| The purpose of this program is to develop GaN power MOSFETs and IGHFETs using novel gate dielectrics. In the past year we have: 1) demonstrated low Dit, 1-4 x 10(exp 11) eV(exp -1)/sq cm, oxide/GaN interfaces using low temperature deposition of Sc2O3 and MgO; 2) investigated the microstructure of the MgO low T dielectric and determined it to be single crystal at the semiconductor interface; 3) demonstrated, for the first ... |
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| Electroluminescence and Spectral Shift of CdS Nanoparticles on Si Wafer |
JAN 2002 |
6 pages |
| Authors:
Eih-Zhe Liang; Ching-Fuh Lin; Sheng-Ming Shih; Wei-Fang Su; NATIONAL TAIWAN UNIV TAIPEI
|
| Preparation of CdS nanoparticles, devices fabrication and electroluminescence properties at room temperature of CdS nanoparticles on silicon substrates are reported. A spectral shift of 8 meV of free exciton transition was observed that was due to the passivation of hydroxyl thiophenol molecules around nanoparticles. Controlled process conditions such as heat treatment and/or with oxygen-rich environment are experimented and found to have significant influences on emission spectra. Radiative recombination corresponding to ... |
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| Chemical and Electronic Properties of Sulfer-Passivated InAs Surfaces |
2002 |
26 pages |
| Authors:
D. Y. Petrovykh; M. J. Yang; L. J. Whitman; MARYLAND UNIV COLLEGE PARK DEPT OF PHYSICS
|
| Treatment with ammonium sulfide [(NH4)2Sx] solutions is used to produce model passivated InAs (001) surfaces with well-defined chemical and electronic properties. The passivation effectively removes oxides and contaminants with minimal surface etching, and creates a covalently bonded sulfur layer with good short-term stability in ambient air and a variety of aqueous solutions, as characterized by x-ray photoelectron spectroscopy (XPS), atomic force microscopy, and Hall measurements. The sulfur passivation also preserves ... |
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| New Approaches to Understanding and Preventing Corrosion of Aluminum and its Alloys |
25 APR 2001 |
3 pages |
| Authors:
Daniel A. Buttry; WYOMING UNIV LARAMIE DEPT OF CHEMISTRY
|
| The general approach in the project is to remove intermetallic inclusions from AA2O24 surfaces by chemical etching. The procedure is to expose the surface to an oxidant, such as persulfate, in the presence of complexing agents, such as ethylene diamine (EN) and EDTA. The objective is to have the complexing agents attack the oxide, and facilitate the oxidative removal of noble metals from the intermetallic inclusions. In order to monitor ... |
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| Etching Chemistry of III-V Semiconductors and the Development of Surface Roughness |
20 NOV 2000 |
6 pages |
| Authors:
Jory A. Yarmoff; CALIFORNIA UNIV RIVERSIDE DEPT OF PHYSICS
|
| This research addressed the need for basic information concerning halogen etching of III-V semiconductors. The reactions of halogens with semiconductor surfaces are the fundamental chemical interactions in processes employed for device manufacture. In this work, the reactions of XeF2, CI2 and I2 with III-V semiconductor surfaces were investigated with synchrotron-based soft x-ray photoelectron spectroscopy, low energy electron diffraction and scanning tunneling microscopy. Fluorine reaction grows films of group III fluorides, ... |
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| New Approaches to Aluminum Passivation for Corrosion Prevention |
31 AUG 1998 |
29 pages |
| Authors:
John T. Yates Jr; PITTSBURGH UNIV PA DEPT OF CHEMISTRY
|
| A new method for producing an aluminum oxide film on an aluminum surface has been discovered. This method involves the activation of adsorbed H2O molecules by the attachment of low energy electrons-producing OH radicals which are aggressive oxidizing agents. Al2 O3 film thickness of up to 25 A are easily achieved. Al2 O3 films made this way are excellent for corrosion passivation as measured electrochemically, and ... |
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| Optoelectronic Computer-Aided Design Models |
31 AUG 1998 |
5 pages |
| Authors:
Joy Laskar; GEORGIA INST OF TECH ATLANTA SCHOOL OFELECTRICAL AND COMPUTER ENGINEERING
|
| This program has focused upon two areas: 1) development of computer aided design models for RF/optical links and 2) development of low cost, wide bandwidth optoelectronic integrated circuits. We have used existing CAD tools to model an optical subcarrier multiplexed (0SCM) communication network to study the effects of RF component integration on system performance and network scalability. The simulation approach presented here enables us to study the effect of RF ... |
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| International Conference on Shallow-Level Centers in Semiconductors (8th) SLCS '98, Held in Montpellier, France on July 27-30, 1998 |
JUL 1998 |
206 pages |
| Authors:
MONTPELLIER UNIV (FRANCE)
|
| Partial contents: Metal-insulator transitions and defect interactions; Bound excitons and Raman scattering at shallow centers; Wide-gap I; Wide-gap II-SiC; Poster Session: Hydrogen passivation and related topics, thermal donors; Low-D systems I; Shallow excited states of deep level impurities and shallow-deep crossover; New methods in experiment. New methods in theory; Low-D systems II; Wide-gap III. |
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| Etching Chemistry of III-V Semiconductors and the Development of Surface Roughness |
13 FEB 1998 |
9 pages |
| Authors:
Jory A. Yarmoff; CALIFORNIA UNIV RIVERSIDE DEPT OF PHYSICS
|
| This research addresses the need for fundamental information concerning halogen etching of III-V semiconductors. The reactions of halogens with semiconductor surfaces are the fundamental chemical interactions in processes employed for device manufacture. In this work, the reactions of XeF2, Cl2 and I2 with III-V semiconductor surfaces were investigated with synchrotron- based soft x-ray photoelectron spectroscopy, low energy electron diffraction and scanning tunneling microscopy. Fluorine reaction grows films of group III ... |
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| Non - Chromium Conversion Coatings on Aluminium |
31 DEC 1997 |
36 pages |
| Authors:
A. Bodnevas; O. Berkh; G. Rogalsky; M. Rotel; J. Zahavi; ISRAEL INST OF METALS HAIFA
|
| In the current period our efforts were concentrated on the without chromate passivation of Al 2024-T3. This material in known to be very prone to both pitting and intergranular corrosion owing to high Cu content (its composition-4.5% Cu, 1.5% Mg, 0.6% Mn) and heat treatment prehistory (solution heat- treated, then strain-hardened). Corrosion accelerates especially in the presence of halogen ions. The actual mechanism by which the Cl- or F- ions ... |
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| New Approaches to Aluminum Passivation for Corrosion Prevention |
10 OCT 97 |
27 pages |
| Authors:
John T. Yates Jr; PITTSBURGH UNIV PA DEPT OF CHEMISTRY
|
| A new method has been discovered for producing a corrosion-resistant aluminum oxide film on aluminum surfaces. The method employs the electronic activation of adsorbed water molecules on the aluminum surface, using electron- bombardment. The artificial oxide film, so produced, exhibits about 25 times higher electrical impedance using electrochemical measurements compared to aluminum oxide films made by conventional oxidation. |
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| Effect of pH, Fluorination, and Number of Layers on the Inhibition of Electrochemical Reactions by Grafted, Hyperbranched Poly(acrylic acid) Films |
31 JUL 97 |
35 pages |
| Authors:
Ninggi Zhao; Merlin L. Bruening; Yuefen Zhou; David E. Bergbreiter; Richard M. Crooks; TEXAS A AND M UNIV COLLEGE STATION DEPT OF CHEMISTRY
|
| We report the electrode-passivation properties of both fluorinated and unmodified hyperbranched poly(acrylic acid) (PAA) films as a function of pH and the number of PAA layers. Both cyclic voltammetry and ac-impedance spectroscopy show that the extent of blocking increases with the number of layers regardless of the solution pH. However, passivation resulting from unfluorinated PAA films decreases with increasing pH while passivation due to fluorinated films increases with increasing pH. ... |
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| Spectroscopic, Voltammetric, and Electrochemical Scanning Tunneling Microscopic Study of Underpotentially Deposited Cu Corrosion and Passivation with Self-Assembled Organomercaptan Monolayers |
31 JUL 1997 |
38 pages |
| Authors:
Francis P. Zamborini; Joseph K. Campbell; Richard M. Crooks; TEXAS A AND M UNIV COLLEGE STATION DEPT OF CHEMISTRY
|
| FTIR-external reflectance spectroscopy (FTIR-ERS), x-ray photoelectron spectroscopy (XPS), electrochemistry, and electrochemical scanning tunneling microscopy (ECSTM) were used to study the effect of thiol adsorbates on the oxidation of underpotentially deposited Cu on Au (Au/Cu-UPD) in HC1O(4)- containing electrolyte solutions. The morphology of the corroding Cu layer and its stripping potential are influenced by the presence of the thiol monolayers. Hexadecanethiol prevented corrosion of Cu-UPD up to potentials more than 1200 ... |
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| The National Shipbuilding Research Program. 1997 Ship Production Symposium, Paper Number 8: Environmentally Acceptable Corrosion Resistant Coating for Aluminum Alloys |
APR 1997 |
9 pages |
| Authors:
A. F. Daech; NEW ORLEANS UNIV LA
|
| A coating system is described that is based on passivation of aluminum alloys by application of Lithium salts as pigments. The resulting composition and morphology of coating films are discussed. Pigment selection applying Greco-Latin Squares statistical method to evaluate corrosion as a function of current flow on 6061-T6 test surfaces was performed. The test device is a potentiostat made by Princeton Applied Research. The pigment is an Aluminum-Lithium powder which ... |
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| Studies Concerning Enhancement of Conductivity of Polymer Electrolytes and Stability of Lithium Anodes |
14 FEB 97 |
93 pages |
| Authors:
N. Munichandraiah; INDIAN INST OF SCIENCE BANGALORE
|
| This report results from a contract tasking Indian Institute of Science as follows: The contractor will investigate the passivation process that can result in increased charge transfer and thin film resistance at the lithium electrode polymer electrolyte interface. |
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| Sidewall Passivation by Oxidation during Refractory-Metal Plasma Etching. |
19 NOV 1996 |
|
| Authors:
John Kosakowski; William Chu; Kelly W. Foster; Christie R. Marrian; Martin C. Peckerar; DEPARTMENT OF THE NAVY WASHINGTON DC
|
 | Sidewalls in a pattern of a refractory metal on a substrate are passivated during plasma etching by introducing water vapor into the etching chamber. This process obtains nearly vertical sidewalls. In one exemplified embodiment, a pattern of tungsten on a chromium etch step layer was reactive ion etched. In that embodiment, the reactive ion etching was intermittently paused. After each pause, the workpiece was warmed from below about 20 deg ... |
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| Scanning Tunneling Microscopy Studies of the Morphology and Kinetic Pathways for Corrosion Reactions of Stressed Materials |
NOV 96 |
16 pages |
| Authors:
Steven J. Sibener; CHICAGO UNIV IL DEPT OF CHEMISTRY
|
| This research program improved our understanding of how surface chemical reactions, surface stress, and atomic level microstructure influence materials oxidation/corrosion processes. Central to this effort was the construction of a new scanning probe microscopy facility which now houses a UHV- STM and a combined STM/AFM for operation in both air and electrochemical environments. It was demonstrated that applied stress fields can influence the electrochemical pitting corrosion chemistry of pure aluminum ... |
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| Inhibition of Electrochemical Reactions at Gold Surfaces by Grafted, Highly Fluorinated, Hyperbranched Polymer Films |
Oct-1996 |
21 pages |
| Authors:
Y Zhou; M Zhao; M Bruening; D E Bergbreiter; R M Crooks; TEXAS A AND M UNIV COLLEGE STATION DEPT OF CHEMISTRY
|
| We report the synthesis and passivation properties of surface-grafted, highly fluorinated, hyperbranched poly(acrylic acid) (PAA) films that contain 50 atom% F; These films are very hydrophobic (water contact angle of 114 deg) and block electrochemical reactions on gold electrodes. Cyclic voltammetry in basic solution shows that while an electrode covered with a 3-layer PAA (3-PAA) film mimics an assembly of microelectrodes, a fluorinated 3-layer PAA (3-PAA/F) film blocks nearly all ... |
|
| Volatile Organic Compound (VOC) Compliant Wash Primer |
JUL 96 |
15 pages |
| Authors:
Kestutis G. Chesonis; Christopher E. Miller; ARMY RESEARCH LAB FORT BELVOIR VA
|
| DoD-P-15328 wash primer is a unique coating that passivates metal surfaces against corrosion and enhances adhesion of primers/topcoats. However, the chromate and high-solvent content subject it to strict Environmental Protection Agency (EPA) regulations. This report evaluated waterborne (WB) polymers and coating systems as in earlier investigations. Laboratory evaluations revealed a film-softening effect when topcoated with solvent-type primers due to trapped solvents in the wash primer. Wash primers formulated with VOC-exempt ... |
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| Optoelectronics Research Center |
12 JUN 96 |
7 pages |
| Authors:
S. R. Brueck; NEW MEXICO UNIV ALBUQUERQUE
|
| The AFOSR Optoelectronics Research Center at the University of New Mexico has continued its aggressive, broadly ranging program. Novel InGaAs and AlGaAs device structures such as resonant-periodic-gain surface-emitting lasers and high-power, coherent unstable resonator wide-stripe lasers have been pioneered. Processing advances have included investigation of III-V regrowth over patterned wafers allowing unique device structures such as unstable laser arrays, and the extension of interferometric lithography techniques has led to the ... |
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| Fluoroalkyl Iodide Photodecomposition on Diamond(100)-An Efficient Route to the Fluorination of Diamond Surfaces |
96 |
7 pages |
| Authors:
V. S. Smentkowski; J. T. Yates Jr; PITTSBURGH UNIV PA
|
| The photodecomposition of CF3I and C4F9I overlayers at 119K on diamond (100) surfaces has been shown to be an efficient route to fluorination of the diamond surface. X-ray photoelectron spectroscopy (XPS) has been used for photoactivation as well as for studies of the following processes: the photodecomposition of the fluoroalkyl iodide molecules: the attachment of the photofragments to the diamond surface; and the thermal decomposition of the fluoroalkyl ligands. Chemisorbed ... |
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| Formation of Semiconductor Interfaces: Proceedings of the Fifth International Conference on the Formation of Semiconductor Interfaces, Princeton, NJ, USA, June 26-30,1995 |
96 |
|
| Authors:
A. Kahn; R. Ludeke; PRINCETON UNIV NJ
|
| This special volume contains the proceedings of the Fifth International Conference on the Formation of Semiconductor Interfaces. This fifth edition of the conference is aimed at providing a review of state of the art experimental and theoretical research on structural and electronic properties of semiconductor interfaces. The scientific program focused on various aspects of (1) semiconductor nanostructures, (2) thin insulators on semiconductors, (3) highly lattice mismatched heterostructures, (4) passivation and ... |
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| The Properties of Thermally Passivated Si(1-x)Ge(x) Produced Using High Pressure Techniques |
96 |
21 pages |
| Authors:
BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
|
| The focus of this work was the development of high pressure techniques for the electronic and chemical passivation of group IV alloy and compound semiconductor surfaces. The project goals were initially focussed on the use of ultra high pressure oxidation to produce high quality Si(1-x)Ge(x) MOS oxides and were expanded, via an ASSERT award, to include a study of the application of this technique to the oxidation of SiC. High ... |
|
| Ambient and Subambient Temperature Polymeric Electrolytes. Synthesis and Physical - Chemical Characterization of Polymer Conductors with Immobilized Ions |
17 OCT 95 |
57 pages |
| Authors:
Zbigniew Florjanczyk; WARSAW TECHNICAL UNIV (POLAND)
|
| The results obtained in several laboratories have clearly demonstrated that the lithium electrode undergoes serious passivation when in contact with highly conducting gel electrolytes. This results mainly from the high reactivity of lithium toward the organic solvents present in gels. In order to decrease the interfacial resistance, electrolytes are sought for, which would be less aggressive towards lithium, or systems are used, in which lithium metal electrode is replaced by ... |
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| High Power, High Efficiency MESFETs and HEMTs |
14 JUN 95 |
8 pages |
| Authors:
Umesh K. Mishra; CALIFORNIA UNIV SANTA BARBARA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| For the duration of the project dated above, the work on the AASERT program concentrated on improving the power performance of GaAs MESFETs with LTG GaAs surface passivation layers by studying the effects of source and drain contacts regrown by MOCVD on both device breakdown and gain. |
|
| Sidewall Passivation by Oxidation During Refractory-Metal Plasma Etching. |
14 APR 1995 |
19 pages |
| Authors:
John Kosakowski; William Chu; Kelly W. Foster; Christie R. Marrian; Martin C. Peckerar; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| Sidewalls in a pattern of a refractory metal on a substrate are passivated during plasma etching by introducing water vapor into the etching chamber. This process obtains nearly vertical sidewalls. In one exemplified embodiment, a pattern of tungsten on a chromium etch step layer was reactive ion etched. In that embodiment, the reactive ... |
|
| Hydrogen Migration and Complex Formation in Technologically Important III-V and II-VI Semiconductors and Their Alloys |
APR 95 |
41 pages |
| Authors:
N. M. Johnson; XEROX PALO ALTO RESEARCH CENTER CA
|
| Experimental and theoretical studies were conducted to identify basic mechanisms and provide quantitative information on the properties of hydrogen in selected (technologically-important) III-V and II-VI semiconductors and their alloys. Hydrogen interactions with dopants and deep level defects were investigated in GaAs, AlGaAs, InGaAs/AlGaAs quantum wells, GaP, GaN, and ZnSe. The diffusivity of H+ in GaAs was determined with a new capacitance transient technique, which provided the first direct quantitative determination ... |
|
| Investigation of GaAs Layers Grown by Molecular Beam Epitaxy at Low Temperature |
10 MAR 95 |
|
| Authors:
Chang-Lee Chen; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
|
| Over the three-year course of this program, the low-temperature- grown (LTG) GaAs and AlGaAs have been incorporated as the gate insulator or surface passivation in a variety of field-effect-transistors (FETs). The LTG gaAs used as the surface passivation layer in a metal-semiconductor FET (MESFET) with a novel overlapping gate structure increased the breakdown voltage by two folds compared to a regular MESFET. The LTG GaAs passivation also greatly improved the ... |
|
| Composite Polymer Electrolyte for Lithium Batteries |
MAR 95 |
17 pages |
| Authors:
Steve Slane; Mark Salomon; ARMY RESEARCH LAB FORT MONMOUTH NJ
|
| Composite polymer electrolyte films consisting of zeolite powders dispersed in poly(acrylonitrile)(PAN) based gels with lithium hexafluoroarsenate have been prepared and their electrochemical properties studied. Gel electrolytes prepared by adding lithium hexafluoroarsenate in propylene carbonate (PC) and ethylene carbonate (EC) mixtures with PAN have demonstrated ionic conductivities greater than 0.001 siemens per cm at room temperature and above. The addition of zeolite powders increased ionic conductivity at low temperatures due to ... |
|
| Heterostructures (CaSrBa)F2 on InP for Optoelectronics |
1995 |
23 pages |
| Authors:
Sergei L. Pyshkin; MOLDOVA ACADEMY OF SCIENCES KISHINEV INST OF APPLIED PHYSICS
|
| Temperature-reduced MBE growth of group II-a fluorides onto InP( 100) surface as well as optimal cleaning and passivation procedures for InP wafers have been newly developed taking into account exsisting literature data. High quality BaF2 and SrF2 layers onto InP(100) have been grown at 350 deg C under ultra-high vacuum conditions using epitaxial and bulk substrates. MBE and Laser Vacuum Epitaxy (LVE) growth methods for semiconductor-semiconductor (SS) and semiconductor-crystalline dielectric-semiconductor ... |
|
| Fabrication Method for III-V Heterostructure Field-Effect Transistors. |
15 NOV 1994 |
|
| Authors:
J. B. Boos; Walter Kruppa; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A heterojunction device, and a method for producing the device. A gate air bridge is formed at the mesa sidewall between the active region and the gate bonding pad to lower the gate leakage current. The device has a double recessed gate to reduce local fields in the vicinity of the gate. The fabrication method uses dielectric intermediate and final passivation layers to optimize the double-recess profile and control the ... |
|
| FTIR Studies of CH3OH On Porous Silicon |
NOV 94 |
9 pages |
| Authors:
John A. Glass Jr.; Edward A. Wovchko; John T. Yates Jr; PITTSBURGH UNIV PA SURFACE SCIENCE CENTER
|
| Fourier transform infrared spectroscopy (FTIR) was used to investigate the reaction of methanol with porous silicon and hydrogen passivated porous silicon. At 300 K methanol adsorbs onto hydrogen free porous silicon by cleavage of the O-H bond. Both of the resulting surface species, Si-H and Si- OCH3, were determined to be stable up to approx. 500 K. Above 500 K the Si-0CH3 moiety decomposes by breakage of the C-O and ... |
|
| Using Nonequilibrium Alloying Techniques for Corrosion Inhibition in Gr/ Al and Gr/Mg Metal Matrix Composites |
15 JUN 94 |
73 pages |
| Authors:
B. A. Shaw; W. C. Moshier; R. G. Wendt; P. L. Miller; A. E. Krebs; PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF ENGINEERING SCIENCE AND MECHA NICS
|
| Metal matrix composites (MMCs) have been heavily studied over the past thirty years. During that period, many proposals have been made to develop a matrix alloy that was compatible with the reinforcing phase. However, for one reason or another, the technology has continued to focus on conventional alloys and fabrication practices. Although tremendous advances have been made on composite materials, the basic technology remains similar to systems studied twenty years ... |
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| Evaluation of Environmentally Acceptable Multi-Layer Coating Systems as Direct Substitutes for Cadmium Plating on Threaded Fasteners, Tri-Service Committee on Corrosion Proceedings Held in Orlando, Florida on June 21-23 1994 |
JUN 94 |
21 pages |
| Authors:
Mark W. Ingle; I. C. Handsy; B. S. Schorr; TRI-SERVICE COMMITTEE ON CORROSION WRIGHT-PATTERSON AFB OH
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| Cadmium has been identified by the United States Army's Tank and Automotive Command as a threat to worker health and the environment. Based on already completed cadmium substitute testing, an evaluation program was conducted to quantify the performance of environmentally acceptable, multi-layer coatings that could be directly substituted for cadmium on threaded fasteners. The performance issues investigated included coating system lubricity and corrosion control performance. Data were generated from both ... |
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| Development of Si Light Emitting Technology Based on Si Quantum Wires |
31 MAR 94 |
29 pages |
| Authors:
Dim-Lee Kwong; TEXAS UNIV AT AUSTIN
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| The objectives of this program are four folds. (1) Process development: develop new techniques to fabricate luminescent PS, control the luminescence spectra, and process PS with minimal damage to the luminescent properties. To that end, we have developed a novel approach to produce luminescent PS without an external electrical bias by stain etching Si in HF- HNO3-based solution. In addition, we have utilized dry oxidation to efficiently control the PL ... |
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| Electrochemical Behavior and Surface Chemistry of Nonequilibrium Aluminum Alloys: Passivity Mechanism and Fabrication Methods |
17 JAN 94 |
30 pages |
| Authors:
G. D. Davis; B. A. Shaw; B. J. Rees; A. Lyengar; E. L. Principe; MARTIN MARIETTA LABS BALTIMORE MD
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| The electrochemical behavior of sputter-deposited nonequilibrium stainless aluminum alloys and different methods to produce bulk or thick-film material have been investigated. Nonequilibrium Al-Ta and Al-W alloys exhibit enhanced passivity over a wide pH range even though the passive film chemistry varies considerably. This enhanced passivity can be explained by the Solute-Rich Interphase Mechanism (SRIM) which states that formation and passivation of occluded cells stabilize the passive film from continued Cl ... |
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| The Effects of Molecular Orientation Geometry and Surface Anisotropy Upon Etching |
DEC 93 |
3 pages |
| Authors:
Andrew C. Kummel; CALIFORNIA UNIV SANTA BARBARA
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| Sticking probabilities have been measured for molecular chlorine upon the GaAs (100) Ga-rich c(8x2), GaAs(100) As-rich C(2.8) and GaAs(110) stoichiometric (1x1) surfaces. The sticking probability has measured as a function of incident translational energy (0.038 to 0.66 eV), surface temperature (150 K - 835 K), angle of incidence (0 deg to 37 deg), and surface chlorine coverage. Our data indicate the presence of both precursor and direct activated chemisorption mechanisms ... |
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| Environmentally Assisted Cracking of High Strength Beta Titanium Alloys |
NOV 93 |
118 pages |
| Authors:
VIRGINIA UNIV CHARLOTTESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| The objective of this integrated research program is to define the conditions under which high strength Beta-titanium alloys resist environmentally assisted cracking (EAC) in marine environments. Specific goals are to: (1) characterize EAC for metallurgical, chemical and mechanical conditions that could destabilize crack tip passive films to promote local dissolution and hydrogen (H) uptake, (2) test the hydrogen embrittlement mechanism for EAC, and (3) develop a mechanism-based model of EAC ... |
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Reports by Keyword(s)
PASSIVITY
