Filters: Department: "Materials Science & Engineering" Collection: "ir_uspace" Type: "Text" Format: "application/pdf"
| Creator | Title | Description | Subject | Date | ||
|---|---|---|---|---|---|---|
| 226 |
 |
Liu, Feng | Thermal roughening of a thin film: a new type of roughening transition | The equilibrium thermal roughening of thin Ge layers (one and two monolayers) deposited on Si(001) has been investigated with low-energy electron microscopy. A Ge-coverage-dependent roughening is observed. For two monolayers, the temperature at which imaging contrast is lost due to surface roughness... | Thermal roughening; Roughening transition; Heteroepitaxial growth | 2000-09 |
| 227 |
 |
Liu, Feng | Enhanced growth instability of a strained film on wavy substrate | We demonstrate that the growth of a strained film is inherently less stable on a wavy substrate than on a flat substrate. For small surface undulation, the lowest strain energy state is for the film surface to adopt the same wavelength as the substrate surface in an antiphase configuration at the ea... | Growth instability; Strained film; Wavy substrate; Strain induced self-assembly | 2008 |
| 228 |
 |
Stringfellow, Gerald B. | Te doping of GaInP: ordering and step structure | The donor Te has been added to GaInP during organometallic vapor phase epitaxial growth using the precursor diethyltelluride. In agreement with previous studies, the addition of high Te concentrations leads to the elimination of the CuPt ordering observed in undoped layers. The degree of order is es... | Epitaxial growth; Heterostructures; Growth parameters | 1999-04-01 |
| 229 |
 |
Scarpulla, Michael | Effect of film thickness on the incorporation of Mn interstitials in Ga1-xMnxAs | We have investigated the effect of film thickness on the distribution of Mn atoms at various lattice sites in Ga1−xMnxAs thin films. We find that the growth surface acts as a sink facilitating the outdiffusion of Mn interstitials sMnId, and thus reducing its concentration in the film. The outdiffu... | Interstitials; Gallium arsenide | 2005 |
| 230 |
 |
Stringfellow, Gerald B. | Surface photoabsorption study of the effect of substrate misorientation on ordering in GaInP | Substrate orientation strongly affects Cu-Pt ordering in Ga0.5In0.5P layers grown by organometallic vapor phase epitaxy. In situ surface photoabsorption SPA measurements were used to measure the concentration of 1 10-oriented P dimers, characteristic of the 2 4 reconstructed surface, as a functio... | P-dimer concentration; Photoluminescence measurements; Surface reconstruction | 1996-04-15 |
| 231 |
 |
Stringfellow, Gerald B. | GaInAsSb metastable alloys grown by organometallic vapor phase epitaxy | Ga1-xlnx As1-ySby alloys have been grown by organometallic vapor phase epitaxy using trimethyl compounds of Ga, In, As, and Sb(TMGa, TMIn, TMAs, and TMSb) plus AsH3 in an atmospheric pressure, horizontal, infrared heated reactor. For the first time, alloys near the center of the region of solid immi... | Organometallic; Alloys; Vapor phase epitaxy | 1986 |
| 232 |
 |
Liu, Feng | Magnetization on vicinal ferromagnetic surfaces | Using Ising model Monte Carlo simulations, we show a strong dependence of surface magnetization on surface miscut angle. For ferromagnetic surfaces, when surface spin exchange coupling is larger than that of the bulk, the surface magnetic ordering temperature decreases, toward the bulk Curie tempera... | Vicinal ferromagnetic surfaces; Surface magnetization; Surface miscut angle | 1997 |
| 233 |
 |
Tiwari, Ashutosh | Room-temperature solid-state radiation detectors based on spintronics | In this paper we are presenting a unique approach to solve the thermal background problem encountered in semiconductor nuclear detectors. Our approach addresses above challenge by making a shift from 'electronic detection mechanism' to 'spintronic detection mechanism'. The proposed methodology is ba... | 2012-01-01 | |
| 234 |
 |
Smith, Grant D. | Molecular dynamics simulation studies of the influence of imidazolium structure on the properties of imidazolium/azide ionic liquids | Atomistic molecular dynamics simulations were performed on 1-butyl-3-methyl-imidazolium azide [bmim][N3], 1-butyl-2,3-dimethylimidazolium azide [bmmim][N3], and 1-butynyl-3-methylimidazolium azide [bumim][N3] ionic liquids. The many-body polarizable APPLE&P force field was augmented with parameters ... | 2012-01-01 | |
| 235 |
 |
Scarpulla, Michael | Pulsed and continuous wave solid phase laser annealing of electrodeposited CuInSe2 thin films | Cu(In,Ga)Se2 (CIGS) thin film photovoltaic absorber layers are primarily synthesized by vacuum based techniques at industrial scale. In this work, we investigate non-vacuum film synthesis by electrochemical deposition coupled with pulsed laser annealing (PLA) and or continuous wave laser annealing (... | 2012-01-01 | |
| 236 |
 |
Liu, Feng | Spatial and energy distribution of topological edge states in single Bi(111) bilayer | By combining scanning tunneling microscopy and spectroscopy, angle-resolved photoemission spectroscopy, and density functional theory band calculations, we directly observe and resolve the one-dimensional edge states of single bilayer (BL) Bi(111) islands on clean Bi2Te3 and Bi(111)-covered Bi2Te3 s... | 2012-01-01 | |
| 237 |
 |
Liu, Feng | A three-layer-mesh bridging domain for coupled atomistic-continuum simulations at finite temperature: formulation and testing | Although concurrent multiscale methods have been well developed for zero-temperature simulations, improvements are needed to meet challenges pertaining to finite-temperature simulations. Bridging domain method (BDM) is one of the most efficient and widely-used multiscale atomistic-continuum techniqu... | 2014-01-01 | |
| 238 |
 |
Tiwari, Ashutosh | Band-gap engineering of Zn1-xGaxO nanopowders: synthesis, structural and optical characterizations | We report the preparation and detailed structural and optical characterizations of single phase gallium doped ZnO nanopowders. A low temperature solution-based technique was developed to synthesize high-purity Zn1−xGaxO (x:0-0.05) nanopowders. Structural and optical characterization experiments we... | Zinc gallium oxide; ZnGaO; Nanopowders; Band-gap engineering | 2008 |
| 239 |
 |
Tiwari, Ashutosh | Epitaxial growth of ZnO films on Si(111) | In this paper, we report the growth of ZnO films on silicon substrates using a pulsed laser deposition technique. These films were deposited on Si(111) directly as well as by using thin buffer layers of AlN and GaN. All the films were found to have c-axis-preferred orientation aligned with normal to... | Buffer layers; Aluminum nitride; Silicon substrate; Biaxial strain | 2002 |
| 240 |
 |
Tiwari, Ashutosh | Electron tunneling experiments on La0.7A0.3MnO3 (A=Ca, Sr, Ba) | Tunneling conductance measurements of the electronic density of states of perovskite manganates, La0.7A0.3MnO3 are reported. Tunneling data of all the samples show a zero-bias anomaly with a minimum in the density of states at the Fermi level. This behavior is interpreted as arising from strong elec... | Perovskite manganates; Tunneling conductance | 1999-10 |
| 241 |
 |
Stringfellow, Gerald B. | Control and characterization of ordering in GaInP | Gae,,In,,P layers have been grown by organometallic vapor phase epitaxy on GaAs substrates with [llO]-oriented grooves on the surface that have an important effect on the formation of Cu-Pt ordered structures during growth. In this work, the groove shape is demonstrated to be critically important... | Vapor phase epitaxy; Ordered structure; Cathodoluminescence spectroscopy | 1993-06-28 |
| 242 |
 |
Bedrov, Dmitro; Smith, Grant D. | Exploration of conformational phase space in polymer melts: a comparison of parallel tempering and conventional molecular dynamics simulations | Parallel tempering molecular dynamics simulations have been performed for 1,4-polybutadiene polymer melts in the 323 K-473 K temperature domain at atmospheric pressure. The parallel tempering approach provides a vast improvement in the equilibration and sampling of conformational phase space for ... | Polymer melts; 1,4-polybutadiene; Conformational phase space; Parallel tempering | 2001 |
| 243 |
 |
Scarpulla, Michael | Probing semiconductor band structures and heterojunction interface properties with ballistic carrier emission: GaAs/AlxGa1-xAs as a model system | Utilizing three-terminal tunnel emission of ballistic electrons and holes in a planar tunnel transistor with a Mott-barrier collector, we have developed a method to self-consistently determine the energy gap of a semiconductor and band discontinuities at a semiconductor heterojunction without using... | 2010-06 | |
| 244 |
 |
Tiwari, Ashutosh | Ferromagnetism in Cu-doped ZnO films: role of charge carriers | We report the observation of room temperature ferromagnetism in Cu-doped (5%) ZnO films grown on c-plane sapphire substrates. Films were prepared by pulsed laser deposition technique and were thoroughly characterized using several state-of-the-art characterization techniques. Hall measurements sho... | Charge carriers | 2008 |
| 245 |
 |
Tiwari, Ashutosh | Metal-insulator transition in La0.7Sr0.3Mn1-xFexO3 | We report the effect of Fe doping at the Mn site in La0.7Sr0.3MnO3 oxides. We find that the doping of Fe does not cause any structural change, but the electrical transport in the system is strongly affected. The parent compound La0.7Sr0.3MnO3 shows a resistivity peak at T=Tp (365 K) and behaves as ... | Tunneling conductance; Perovskite manganates; Iron doping; Fe doping | 1999 |
| 246 |
 |
Liu, Feng | Fabricating artificial nanowells with tunable size and shape by using scanning tunneling microscopy | The authors report a method of precisely fabricating the large-scale nanocrystals with well-defined shape and size. The (111) oriented Pb islands deposited on Si(111)-7x7 substrate were investigated with a manipulation technique based on scanning tunneling microscopy. By applying a series of voltage... | Artificial nanowells | 2006 |
| 247 |
 |
Liu, Feng | Self-organization of steps in growth of strained films on vicinal substrates | Computer simulations show that if stress is present, steps on a vicinal surface can self-organize into a regular array of step bunches. Such self-organization can provide templates for subsequent fabrication of "quantum wire" nanostructures. The size and spacing of the bunches can be controlled inde... | Self-organization; Strained films; Growth; Vicinal substrates; Step bunches | 1998-02 |
| 248 |
 |
Tiwari, Ashutosh | Epitaxial growth and properties of MoOx(2 | We report the growth of epitaxial molybdenum oxide (MoOx,2<x<2.75) films on c plane of sapphire substrate using pulsed laser deposition in oxygen environment. The structure was characterized using x-ray diffraction, high resolution transmission electron microscopy and x-ray photoelectron spectroscop... | Epitaxy; MoO | 2005 |
| 249 |
 |
Bedrov, Dmitro; Smith, Grant D. | Equilibrium sampling of self-associating polymer solutions: a parallel selective tempering approach | We present a novel simulation algorithm based on tempering a fraction of relaxation-limiting interactions to accelerate the process of obtaining uncorrelated equilibrium configurations of self-associating polymer solutions. This approach consists of tempering (turning off) the attractive interactio... | Equilibrium sampling; Self-associating systems; Parallel selective tempering | 2005 |
| 250 |
 |
Liu, Feng | Theory of hydrogen pairing in yttrium | The energetics of hydrogen atoms interacting with yttrium have been investigated using the self-consistent cluster model and the local-density approximation. Our results provide a theoretical understanding of a range of novel phenomena observed recently in resistivity, neutron scattering, NMR, and ... | Hydrogen pairing; Self-consistent cluster model; Local-density approximation; Energetics | 1989-09 |