bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Type of Cation-Conducting Rubbery Solid Electrolyte: The Ionic Rubber
Authors: Angell C. A. , Liu Changle , Sanchez E. 
Published: March 2011

AbstractWe show that the conductivity maximum, well known for salt-in-polymer electrolytes is not the maximum conductivity in the system when the salts used are chosen for their resistance to crystallization at high concentration. The polymer + salt system, with increasing salt content, goes through a transition zone characterized by a maximum in glass transition temperature. Beyond this point additional salt serves to plasticize the salt-crosslinked polymer system, establishing thereby a region of increasing conductivity in which the conductivity can reach very large values. We show that “polymer in-salt” solutions constitute a new type of rubbery solid electrolyte in which the conductivity is dominated by cation motion. Such systems are true hybrids of the previously distinct “superionic glass” and “polymer electrolyte” types of amorphous solid conductors.
Deuteron and Oxygen-17 NMR Studies of Molecular Motion in Methanol-Saturated Nafion Membranes
Authors: Chen R.S. , Jayakody J.R.P. , Greenbaum S.G. 
Published: March 2011

AbstractDeuteron and oxygen-17 NMR linewidth and spin-lattice relaxation measurements in Nafion-117 films containing methanol at σ75% and σ100% saturation are reported. Molecular motion probed by room temperature measurements in stretched films and low T measurements in unstretched films is found to be quite rapid compared to previous results obtained for Nafion-117 containing water.
Comparisons Of Observed And Simulated Atomic Structures Of Pd/NiO Heterophase Interfaces
Authors: Buckett M. I. , Shaffer J. P. , Merkle Karl L. 
Published: March 2011

AbstractHigh-resolution electron microscopy (HREM) and image simulations using the multislice algorithm have been used to study the atomic structure of a Pd/NiO (111) interface in an intemally oxidized sample. Samples prepared in this way result in cube-on-cube oriented or twin-related precipitates whose (111) interfaces exhibit a contrast modulation along the boundary plane in HREM images. Previous studies have reported that the observed structural period of this modulation corresponds qualitatively to the expected spacing if the boundary was composed of a network of misfit dislocations. In this study, rigid models of the (111) interface as viewed from the [110] direction were simulated using the EMS suite of programs. The questions we address are: (1) whether the terminating plane on the oxide side is made up of a Ni or an 0 layer, and (2) whether a rigid body translation normal to the interface exists. Finally, the results of the simulations are compared and contrasted to through-focal experimental images to investigate the origin of the contrast modulations and their possible relation to the extent of the misfit localization in these systems.
A Microstructural Study of Reaction-Bonded Silicon Carbide
Authors: Chowdhury K. Das , Carpenter R. W. , Braue W. 
Published: March 2011

AbstractInterfaces in Reaction Bonded Silicon Carbide (RBSC) have been characterized by Analytical and High Resolution Electron Microscopy. Both Si/SiC and SiC/SiC interfaces were free of any oxygen impurity segregation, but contained metallic impurity precipitates. Oxygen was detected in the second phase particles in the SiC grains. A model is presented to explain the evolution of these second phase particles in the SiC grains.
Atomic Structures and Defects of As-Grown Nb1+αS2 Platelets on Nb Substrates
Authors: Zhou Chuxin , Hobbs L. W. 
Published: March 2011

AbstractThe interlocking of Nb1+αS2 platelets developed during sulfidation of Nb results in formation of a compact scale. The atomic structure and defects of these platelets were investigated using HREM. The resulting microstructure is very different from conventional microstructure consisting of polygonal grains and polyhedral grain boundaries because of the anisotropy of the crystal structure. The principal phase was identified as 3R-Nb2+αS2 intergrown with 2H-Nb1+αS2, or with some other arrangement of S-Nb-S slabs. The -S6- octahedral sites between two S-Nb-S slabs provide accommodation for extra Nb or foreign atoms and the large non-stoichiometry of Nb1+αS2. Stacking faults along the c axis account for the high density of planar defect structures observed within almost every platelet. Axial lattice fringe images and streaking in the diffraction pattern indicate that the planar defects are normal to the c direction.
Application of Z-Contrast Imaging to Obtain Column-by-Column Spectroscopic Analysis of Materials
Authors: Browning Nigel D. , Pennycook Stephen J. 
Published: March 2011

AbstractZ-contrast imaging has been shown to be an effective method for obtaining a highresolution image from a scanning transmission electron microscope (STEM). The incoherent nature of the high-angle scattering makes image interpretation straightforward and intuitive with the resolution limited only by the 2.2 Å electron probe. The optimum experimental conditions for Z-contrast imaging also coincide with those used for analytical microscopy, enabling microanalysis to be performed with the same spatial resolution as the image. The detection limits afforded by a parallel detection system for electron energy loss spectroscopy (EELS) allows column-by-column core-loss spectroscopy to be performed using the Z-contrast image to position the electron probe. Preliminary results from the study of Yba2Cu3O7-δ illustrate the spatial resolution available with this technique and the potential applications for materials science.
Scanning Tunneling Microscopy for Hydrogen-Desorptioninduced Structural Change of Si(111) Surface
Authors: Morita Y. , Miki K. , Tokumoto H. , Sato T. , Sueyoshi T. , Iwatsuki M. 
Published: March 2011

AbstractA scanning tunneling microscopy (STM) has revealed an atomic structure of Si(111)-√3× √3R30° which is induced by the hydrogen desorption at about 500 °C. There exist domains with the √3× √3R30° structures, indicating that each domain is formed by rearrangement of Si adatoms around each cluster present at room temperature. Near the domain boundary, the adatoms locate mostly at T4 sites and occasionally at H3 sites. The dynamic nature of the adatoms are predicted.
Metastable Structural Surface Excitations and Concerted Adatom Motions: a STM Study of Atomic Motions Within a Semiconductor Surface
Authors: Golovchenko Jene , Hwang Ing-Shouh , Ganz Eric , Theiss Silva K. 
Published: March 2011

AbstractKnowledge about atomic scale motions is essential to the understanding of dynamical phenomena on surfaces, such as diffusion, phase transitions, and epitaxial growth. We demonstrate that the addition of a very small number of Pb atoms to a Ge(111) surface reduces the energy barrier for activated processes, thus allowing one to observe concerted atomic motions and metastable structures on this surface near room temperature using a tunneling microscope. The activation energy for surface diffusion of isolated substitutional Pb atoms in Ge(111)-c(2×8) was measured by observing individual atomic interchanges from 24°C to 79°C. We also observed the formaticn and annihilation of metastable structural surface excitations, which are associated with large numbers of germanium surface atoms in one row of the c(2×8) reconstruction shifting along that row like beads on an abacus. The effect provides a new mechanism for atomic transport on semiconductor surfaces and can explain a number of other observed phenomena associated with Ge(111) surfaces, including the surface diffusion of Pb atoms.
Atomic Arrangement of Al Near the Phase Boundaries Between-√3X-√3-Al and 7X7 Structures on Si(111) Surfaces
Authors: Takaoka Katsuya , Yoshimura Masamichi , Yao Takafumi , Sato Tomoshige , Sueyoshi Takashi , Iwatsuki Masashi 
Published: March 2011

AbstractScanning tunneling microscopy (STM) is used to study the structure of Al-√3×√3 domains on the Si(111)-7×7 surface and the atomic arrangement near the domain boundary. Al-√3×√3 domains grow from the lower side of the <112> step and extend over the Si-7×7 terrace. The phase transition is observed to occur in units of the 7×7 size. Detailed investigation at around the boundary reveals that faulted halves of the 7×7 unit are adjacent to the boundary on the Si-7×7 side, while on the Al-√3×√3 side, Al adatoms occupy the T4 sites except for the rows adjacent to the phase boundaries where Al atoms occupy the Si adatom sites. The latter Al atoms play an important role to retain the dimer structure at the boundary.
Steps on the (110) Surface of INP
Authors: Liang Yong , Packard William E. , Dow John D. 
Published: March 2011

AbstractThree types of steps are observed on the cleaved InP(110) surface, using atomicresolution ultra-high vacuum (UHV) scanning tunneling microscopy (STM). The step edges are oriented along the (110), (111), and (112) directions. Atomic models of monatomic-height (111) and (112) steps indicate that the edges of each of these unrelaxed steps should have pairs of dangling bonds. We propose that the bonds dimerize, causing the edges to relax and form periodic structures along the edge.
Hrtem Observations Of A Σ=3 {112} Bicrystal Boundary In Aluminum
Authors: Medlin D. L. , Mills M. J. , Stobbs W. M. , Daw M. S. , Cosandey F. 
Published: March 2011

AbstractWe present here a study of the Σ=3 {112} incoherent twin boundary in aluminum. Atomistic studies of this boundary indicate that several high energy boundary structures may exist, with the lowest energy structure exhibiting a small rigid body shift parallel to the boundary. The observations presented here indicate that the rigid body shift does in fact occur and that its magnitude, as well as the local grain boundary structure, is well predicted by atomistic calculations using the Embedded Atom Method. The low energy boundary configuration is much narrower than the equivalent boundaries that have been observed in the lower stacking fault energy FCC metals.
Role of Photodegradation on the \x03C4;Product and Microstructure of the a-Si:H Pin Devices
Authors: Vieira M. , Fortunato E. , Lavareda G. , Carvalho C.N. , Martins R. 
Published: March 2011

PIN solar cells were light soaked up to 60 hours. The cell characteristics, the optoelectronic properties and the microstructure parameter (R=I2100/I2100+I2000) as well as the hydrogen content (CH) and density of states (g(Ef)) of the active i-layer were monitored throughout the entire light induced degradation process and compared with the correspondents μτ product (for both carriers) inferred through steady photoconductivity and FST measurements.Data show a strong correlation between the decrease of μτ product for electron and the increase of the fraction of hydrogen bonded on internal surfaces (R increases from 0.1 to 0.4) suggesting structural changes during the light induced defects' formation. For holes, the μτ product remains approximately constant and only dependent on the initial hydrogen content. As g(Ef) increases, μτ presents an asymmetrical decrease showing that electrons are more sensitive to defects' growth than holes.We also observe that the rate of degradation is faster for samples having the lowest defect densities, R and CH, showing that the amount of degradation is not a simple function of the photon exposure (Gt product) but also depends on the material microstructure.
The Relation Between Microstructure and Electronic Properties of Magnetron Sputtered a-Si1−x,Cx:H
Authors: Yang S.Y. , Maley N. , Abelson J.R. 
Published: March 2011

We have grown a-Si1-x,Cx:H films by reactive magnetron sputtering, varying the H2 partial pressure from 0 to 6 mTorr and maintaining the substrate temperature at 275°C and argon and methane partial pressures at 1.70 and 0.10 mTorr, respectively.We investigate the correlation between electronic properties and the fraction of H bonded in "microstructure," defined by the ratio of SiHx stretching mode absorptions in IR and the low temperature H2release in thermal evolution. Our results on sputtered films disprove the monotonic decrease in carrier transport with increasing microstructure fraction which is commonly observed for a-Si1-xCx:H grown by glow discharge of SiH4 and CH4. We find that the electronic properties and microstructure depend on film composition and growth technique, and that the electronic properties are not uniquely determined by the microstructure of hydrogen bonding.
A New Thin Film Transistor Structure for Increasing Storage Capacitance in the Pixel Element
Authors: Min B.H. , Choi H.S. , Park J.S. , Han M.K. 
Published: March 2011

In a high resolution TFT LCD, the ratio of a parasitic capacitance between a gate and a source electrode to the liquid crystal capacitance increase. Increase of the Cgs/Clcmakes the voltage shift of the pixel electrode large. This also results in degradation of the display quality such as image sticking or flicker. The voltage shift can be decreased by increasing the value of a storage capacitor, however, it decreases the aperture ratio.We present a new thin film transistor structure to increase the storage capacitance without reducing the aperture ratio. In the simulation results, we have observed that the pixel voltage shift is remarkably reduced compared with the conventional one.
MÖssbauer Studies of Ion Implanted Alloys
Authors: Longworth G. 
Published: March 2011

ABSTRACTA review is presented of the use of Mössbauer spectroscopy to study the mechanisms responsible for the improvements in wear resistance in ferrous alloys implanted with either light or heavy ions. The phases present in the near surface layers of iron and steel samples implanted with either nitrogen, carbon or tin ions are identified using Conversion Electron Mössbauer Scattering (CEMS) spectra. Samples of wear debris from tin-implanted iron wear discs are analysed in Mössbauer absorption measurements.
Hydrides Examined by Nuclear Magnetic Resonance
Authors: Barnes R. G. 
Published: March 2011

ABSTRACTNuclear magnetic resonance (NMR) methods offer many opportunities for studying both crystal and electronic structure in hydrides, as well as the changes that occur in these at phase transitions. NMR also affords an almost uniquely powerful approach to the study of hydrogen diffusion in hydrides. The NMR of all three hydrogen isotopes can be utilized, as well as of a range of technolgically significant metals. Single crystals are not required, samples need not be single-phase, and measurements can be conveniently made over a wide range of temperatures.
Hyperfine Interaction Investigations of Helium Trapping in Metals
Authors: Waard H. De 
Published: March 2011

ABSTRACTHelium decorated vacancies may be trapped to a high degree and with a high activation enthalpy at impurities in metals. This effect is studied by means of the hyperfine interaction of the radio-active impurities 111In → 111Cd, 119Sb → 119Sn and 129mTe → 129I, implanted into a number of f.c.c. metals and into iron and cobalt. Large changes of the magnetic hyperfine field are caused at 119Sn impurities in Ni, Co and Fe and hiqh values of the electric quadrupole interaction strength are found at 111Cd impurities in Al, Cu, Ag, Ni and Pt when helium decorated vacancies are trapped at the impurities. These effects provide a new method for studying the trapping and desorption mechanism of helium in metals.
The Nature of Fluorine Modified Oxide Surfaces: An Nmr Study
Authors: SCHLUP John R. , Vaughan Robert W. 
Published: March 2011

ABSTRACTFluorine modified oxide surfaces have received considerable attention both as research materials and as commercial catalysts. Pulsed NMR has been used to directly observe protons and fluorine on fluorine modified silica,alumina, and aluminosilicates. The center of mass of the 19F spectra is consistent with values reported for covalent siliconfluorine and aluminum-fluorine bonds. The proton and fluorine concentrations have been investigated as a function of sample preparation.
Electronic Structure of Iron Substituted Lithium Intercalated TaS2
Authors: Eibschütz M. , Murphy D. W. , DiSalvo F. J. 
Published: March 2011

ABSTRACTWe have used the 57Fe Mössbauer effect to study the electronic spin configuration of Fe substituted in the layer compound LixTal-yFeyS2(0≤x≤l;0≤y≤0.1). The Mössbauer effect results show that the Fe is localized and in Fe2+ valence state but the electronic configuration depends on the lithium concentration. At room temperature the isomer shift of Fe2+ increases from 0.56 mm/s for x = 0 (no Li) to 0.77 mm/s for x = .86 (at y = 0.05). The isomer shift results reflect the changes in the electronic configuration of the host from Ta4+(5d1) to Ta3+(5d2) and an increase in ionicity as the lithium content increases from 0 to 1.
Silicide Formation at Fe-Si Interfaces Studied by Mössbauer Spectroscopy and Rutherford Backscattering
Authors: Cohen R. L. , Feldman L. C. , West K. W. , Silverman P. J. 
Published: March 2011

EXTENDED ABSTRACTWe have deposited the Mössbauer isotope Fe 57 on (111) Si surfaces at room temperature and measured the Mössbauer spectrum using conversion electron Mössbauer spectroscopy for enhanced surface sensitivity. Samples were examined as a function of substrate preparation and thermal anneal. Rutherford backscattering was used to monitor sample preparation. The Fe 57 layers have been coated with natural iron (2.2% Fe 57) or silver to prevent them from oxidizing when exposed to air. The known distinctive Mössbauer spectra of Fe, FeSi, FeSi 2 , Fe in Si, and Si in Fe allows the identification of these phases in the samples.
Laser Annealing of Te-Implanted III-V Semiconductors Studied by Mossbauer Spectroscopy
Authors: Van Rossum M. , Dezsi I. , Langouche G. , De Bruyn J. , Coussement R. 
Published: March 2011

ABSTRACTThe laser annealing behaviour of Te-implanted GaAs, GaSb, GaP and InP has been studied by Mössbauer Spectroscopy. The spectra of the as-implanted samples are characterized by a quadrupole split multiplet, showing that the Te ions come to rest at non-substitutional lattice sites. The laser annealing is shown to shift the implanted impurities towards substitutional positions. The efficiency of the laser annealing procedure is very similar for all lattices under study.
A MÖssbauer Study of Microstructural and Chemical Changes in FE-9NI Steel During Two-Phase Tempering
Authors: Fultz B. , Morris J. W. 
Published: March 2011

ABSTRACTTwo-phase tempering of martensitic Fe-9Ni steel serves to enhance the low temperature toughness and forms austenite precipitates in this material. Hyperfine field effects in Fe-Ni alloys were systematized so that tempering induced chemical composition changes in the martensite could be quantified by Mössbauer spectrometry. The kinetics of segregation of alloy elements from the martensite into the fresh austenite can be determined simultaneously with the amount of austenite which has formed.
Interstitial-Atom Trapping and Deuterium Localization at 57Co Impurities in Cu
Authors: Ma C.T. , Makowski B. , Marcuso M. , Boolchand P. 
Published: March 2011

ABSTRACTA high purity Cu target foil doped with 57Co and cooled to 80 K has been deuteron irradiated (E = 2 MeV to .5 MeV) using a Van de Graaff accelerator. In-situ Mössbauer spectra of the target were taken as a function of deuterium dose and post irradiation annealing. Two new 57Co sites are observed in addition to the original substitutional site. The new site ‘1’, populated at low temperature following the irradiations is identified with a 57Co impurity atom having Cu-interstitials trapped in its immediate vicinity. The new site ‘2’, populated on annealing the target above 360 K is believed to represent a 57Co impurity having deuterium localized in its vicinity.
Electron Paramagnetic Resonance of Material Properties and Processes
Authors: Brower K. L. 
Published: March 2011

ABSTRACTThe purpose of this paper is to demonstrate, primarily for the non-specialist and within the context of new and recent achievements, the diagnostic value of electron paramagnetic resonance (EPR) in the study of material properties and processes. I have selected three EPR studies which demonstrate the elegance and uniqueness of EPR in atomic defect studies and exemplify unusual achievements through the use of new techniques for material measurement and preparation. A brief introduction into the origin, interaction, and detection of unpaired electrons is included.
Defects in III-V Semiconductors Studied Through EPR
Authors: Kennedy T. A. 
Published: March 2011

ABSTRACTEPR studies of Cr impurities in GaAs and intrinsic defects in GaP are reviewed to illustrate the contributions that EPR has made to the materials science and technology of III-V semiconductors. EPR has shown how the Cr impurity acts to compensate residual shallow donors or acceptors to produce semi–insulating GaAs which is used for device substrates. EPR work has identified two intrinsic defects, the PGa antisite and the VGa vacancy, and clarified their role in electrical and stoichiometric properties of GaP.
High Power Broad Area GaInAs/GaAs/GaInP Lasers Grown by CBE for Pumping Er Doped Glasses
Authors: Maurel Ph. , Garcia J.C. , Hirtz J.P. , Vassilakis E. , Baldy M. , Parent A. , Carriere C. 
Published: March 2011

ABSTRACTGaInAs/GaAs/GaInP multiquantum well laser structures have been grown by chemical beam epitaxy (CBE) using conventional sources (hydrides as group V element sources). Large area lasers were photolitographically defined and mounted for continuous wave (CW) measurements. CW output power levels of 600 mW at 25°C are reported from 100 μm wide, 300 μm long laser diodes without any facet treatment. At these levels, the delivered current is 2A, with an associated voltage of less than 1.7 V. The characteristic temperature of the structure is 95 K.The same structures were then grown using tertiarybutylarsine (TBAs) and tertiarybutylphosphine (TBP). The large area laser diodes were characterized under pulsed conditions. For a 300 μm long cavity, threshold current density of 390 A/cm2 and external quantum efficiency of 0.6 W/A (2 facets) were obtained, demonstrating the suitability of TBP and TBAs as substitutes of arsine and phosphine in chemical beam epitaxy for laser fabrication.
Recombination at Heterojunction Interfaces
Authors: Müllenborn M. , Haegel N. M. 
Published: March 2011

ABSTRACTGeneration and recombination mechanisms at heterojunction interfaces are quantitatively discussed for lattice-matched (AlGaAs/GaAs) and lattice-mismatched (InGaAs/InP) systems. The effect of increased interface recombination on photon recycling and carrier diffusion through the interface region are estimated through a calculation based on the ambipolar diffusion equation. Experimental photoluminescence power dependencies, revealing information about generation and recombination mechanisms, fit well with calculated photoluminescence intensities. Lifetimes and interface extent can be determined by these fits.