UScholar Works
 
Filters: Department: "Materials Science & Engineering" Collection: "ir_uspace"
201 - 225 of 288
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CreatorTitleDescriptionSubjectDate
201 Stringfellow, Gerald B.Effect of step structure on ordering in GaInPExamines the effect of step structure on ordering in gallium indium phosphite (GaInP) using atomic force microscopy. Coverage of the surface by islands several monolayers in height with elongated direction; Formation of the edges of the islands; Role of the observations in explaining the nature of t...Gallium indium phosphite (GaInP); Twin boundaries1995-11-12
202 Liu, FengKinetics of mesa overlayer growth: climbing of adatoms onto the mesa topWe have calculated the energy barriers for an adatom climbing up onto a Pb mesa top either over a facet-facet edge or through a facet-step joint, using a modified embedded atom method. We found that the second process is not only thermodynamically more favorable than the first one but also much fast...Mesa overlayer growth; Adatoms; Epitaxial growth2008
203 Scarpulla, MichaelMn L3,2 x-ray absorption and magnetic circular dichroism in ferromagnetic Ga1-xMnxPWe have measured the x-ray absorption and x-ray magnetic circular dichroism (XMCD) at the Mn L3,2 edges in ferromagnetic Ga1−xMnxP films for 0.018≤x≤0.042. Large XMCD asymmetries at the L3 edge indicate significant spin polarization of the density of states at the Fermi energy. The temperatur...X-ray absorption; Gallium Arsenide; Ferromagnetic semiconductors2006
204 Stringfellow, Gerald B.Surface photoabsorption transients and ordering in GaInPHeterostructures and quantum wells can be produced in GaInP without changing the solid composition by simply varying the order parameter. Since CuPt ordering reduces the band-gap energy, changes in the order parameter induced by changes in growth conditions result in heterostructures with band-ga...Order parameters; Quantum wells; P-dimers1998-03-15
205 Scarpulla, MichaelMagnetocrystalline anisotropy and magnetization reversal in Ga1-xMnxP synthesized by ion implantation and pulsed-laser meltingWe report the observation of ferromagnetic resonance (FMR) and the determination of the magnetocrystalline anisotropy in (100)-oriented single-crystalline thin film samples of Ga1−xMnxP with x=0.042. The contributions to the magnetic anisotropy were determined by measuring the angular and the te...Magnetocrystalline anisotropy; GaMnAs; Gallium arsenide2007-06
206 Tiwari, AshutoshMethods of forming three-dimensional nanodot arrays in a matrixNanostructures and methods of making nanostructures having self-assembled nanodot arrays wherein nanodots are self-assembled in a matrix material due to the free energies of the nanodot material and/or differences in the Gibb's free energy of the nanodot materials and matrix materials.Nanodots2006
207 Bedrov, Dmitro; Smith, Grant D.Integral equation theory for polymer solutions: explicit inclusion of the solvent moleculesSelf-consistent Polymer Reference Interaction Site Model (PRISM) calculations and molecular dynamics (MD) simulations were performed on athermal solutions of linear polymers. Unlike most previous treatments of polymer solutions, we explicitly included the solvent molecules. The polymers were mode...Solvent molecules; Polymer Reference Interaction Site Model; PRISM; Spinodal curve; Intramolecular dimensions; Intermolecular packing; Phase behavior2001
208 Scarpulla, MichaelNonmagnetic compensation in ferromagnetic Ga1-xMnxAs and Ga1-xMnxP synthesized by ion implantation and pulsed-laser meltingThe electronic and magnetic effects of intentional compensation with nonmagnetic donors are investigated in the ferromagnetic semiconductors Ga1−xMnxAs and Ga1−xMnxP synthesized using ion implantation and pulsed-laser melting. It is demonstrated that compensation with nonmagnetic donors and MnI ...Ferromagnetic semiconductors2008
209 Tiwari, AshutoshSynthesis and atomic-level characterization of Ni nanoparticles in Al2O3 matrixSingle domain magnetic nickel nanocrystals were embedded in alumina matrix using a pulsed-laser deposition technique. Structural characterization carried out at the atomic level using scanning transmission electron microscopy with atomic number contrast (STEM-Z) in conjunction with electron energy ...Nanophase magnetic materials; Alumina2002
210 Liu, FengSeeing the atomic orbital: first-principles study of the effect of tip termination on atomic force microscopyWe perform extensive first-principles calculations to simulate the topographical atomic-force-microscope image of an adatom on the Si(111)-(7 X 7) surface, demonstrating the feasibility of imaging not only the atoms but also the atomic orbitals. Our comparative study of tip terminations shows that ...First-principles; Tip termination; Adatoms2003-06
211 Liu, FengCreation of "quantum platelets" via strain-controlled self-organization at stepsWe demonstrate, by both theory and experiment, the strain-induced self-organized formation of "quantum platelets," monolayer-thick islands of finite dimensions. They form at the early stage of heteroepitaxial growth on a substrate with regularly spaced steps, and align along the steps. In the direc...Quantum platelets; Strain-controlled self-organization; Monolayer-thick islands; Heteroepitaxial growth2000-12
212 Liu, FengSd2 graphene: kagome band in a hexagonal latticeGraphene, made of sp2 hybridized carbon, is characterized with a Dirac band, representative of its underlying 2D hexagonal lattice. The fundamental understanding of graphene has recently spurred a surge in the search for 2D topological quantum phases in solid-state materials. Here, we propose a new ...2014-01-01
213 Scarpulla, MichaelTemperature dependent conductivity of polycrystalline Cu 2ZnSnS 4 thin filmsThe temperature-dependent conductivity of Cu2ZnSnS4 (CZTS) thin films prepared by sulfurization of different sputtered ZnS/Cu/Sn stacks and also of the same stack annealed for different times was investigated from 30-300 K. Fitting of the through-thickness conductivity requires a model including Mot...2012-01-01
214 Scarpulla, MichaelTemperature dependence of equivalent circuit parameters used to analyze admittance spectroscopy and application to CZTSe devicesWe present a device physics and equivalent circuit model for admittance spectroscopy of CZTSe based photovoltaic devices. The experimental variations of the capacitance and conductance in the depletion width are reproduced for state of the art coevaporated CZTSe devices. We will show that simple Arr...2014-01-01
215 Ostafin, AgnesCombined deletion of mouse dematin-headpiece and ß-adducin exerts a novel effect on the spectrin-actin junctions leading to erythrocyte fragility and hemolytic AnemiaDematin and adducin are actin-binding proteins of the erythrocyte "junctional complex." Individually, they exert modest effects on erythrocyte shape and membrane stability, and their homologues are expressed widely in non-erythroid cells. Here we report generation and characterization of double knoc...2007
216 Pugmire, Ronald J.Soot formation during coal pyrolysisSoot can be found in almost all combustion and pyrolysis systems. In a coal system, the impact of soot on coal combustion can be identified in two ways. First, soot particles suspended in the combustion flame significantly enhance radiative heat transfer near the burner due to their large surface ar...2001
217 Scarpulla, MichaelSynthesis of GaNxAs1-x thin films by pulsed laser melting and rapid thermal annealing of N+-implanted GaAsWe present a systematic investigation on the formation of the highly mismatched alloy GaNxAs1-x using N1-implantation followed by a combination of pulsed laser melting and rapid thermal annealing. Thin films of GaNxAs1-x with x as high as 0.016 and an activation efficiency of the implanted N up to 5...Highly mismatched alloys; Gallium arsenide2003
218 Stringfellow, Gerald B.Electron mobility in AlxGa1-xAshe electron mobility in AlxGa1-xAs grown by several techniques has been studied to determine whether VPE layers are more highly compensated than comparable LPE layers. The techniques used to grow layers included (1) organometallic VPE using Al(CH3)3, AsH3, and Ga(C2H5)3 or Ga(CH3)3, (2) ''hybrid'' o...Alloys; Organometallics1979-06
219 Stringfellow, Gerald B.; Rieth, Loren W.Effects of Br and Cl on organometallic vapor phase epitaxial growth and ordering in GaInPCuPt ordering in GaInP has significant effects on the electrical and optical properties. In fact, band gap reductions as large as 160 meV are potentially useful for devices. Thus, control of ordering is important. This has led to the investigation of surfactants that affect the surface processes d...Band gap reductions; Surfactants; Surface processes2004
220 Stringfellow, Gerald B.; Cohen, Richard M.Organometallic vapor phase epitaxial growth of high purity GaInAs using trimethylindiumGax In1−xAs lattice matched to the InP substrate (x=0.47) has been grown by organometallic vapor phase epitaxy using trimethylindium (TMIn) and trimethylgallium (TMGa) as the group III sources and AsH3 as the As source. In a simple, horizontal, atmospheric pressure reactor, the GaInAs growth proce...Electron mobilities; Photouminescience; Fabricate modulation1984-03-01
221 Liu, FengSelf-organized nanoscale pattern formation on vicinal Si(111) surfaces via a two-stage faceting transitionWe demonstrate a self-organized pattern formation on vicinal Si(111) surfaces that are miscut toward the [211] direction. All the patterns, consisting of a periodic array of alternating (7 X 7) reconstructed terraces and step-bunched facets, have the same periodicity and facet structure, independent...Vicinal Si(111); Nanoscale pattern formation; Two-stage; Faceting transition2002-02
222 Liu, FengMagnetism and local order II: self-consistent cluster calculationsThe effect of the local environment on the magnetic moment and its convergence to bulk value has been studied self-consistently by using a molecular-cluster model within the framework of spin-density-functional theory. We show that the magnetic moment of the central atom in clusters of 43 Ni atoms a...Local order; Magnetic moment; Molecular-cluster model; Spin-density-functional theory1989-07
223 Stringfellow, Gerald B.; Sadwick, Laurence P.Low pressure pyrolysis of alternate phosphorus precursors for chemical beam epitaxial growth of InP and related compoundsThe most widely used phosphorous source in chemical beam epitaxy (CBE) is phosphine (PH3). However, because it is highly toxic, alternatives to phosphine have been sought for the growth of phosphorous-containing compounds. We have investigated the pyrolysis rates and reaction products, in low pres...Chemical Beam Epitaxy; CBE1994
224 Stringfellow, Gerald B.Effect of surfactant Sb on carrier lifetime in GaInP epilayersSamples of Ga0.52In0.48P grown on (001) GaAs with small amounts of surfactant Sb were investigated using time-resolved photoluminescence. All samples show a luminescence that may be fit to a two-stage exponential decay with a fast and a slow lifetime. For growth without Sb (Sb/III(v)(0), the sample ...Semiconductor ternary alloys; Epitaxial layer; Microstructures2002-01-01
225 Smith, Grant D.; Bedrov, DmitroNMR experiments and molecular dynamics simulations of the segmental dynamics of polystyreneWe have performed NMR spin?lattice relaxation experiments and molecular dynamics (MD) computer simulations on atactic polystyrene (a-PS). The segmental correlation times of three different molecular weight a-PS (Mn = 1600, 2100, 10 900 g/mol) were extracted from NMR by measuring the 2H spin?lattice ...2004
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