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226 Liu, FengSelf-organized replication of 3D coherent island size and shape in multilayer heteroepitaxial filmsA model is proposed to elucidate the evolution of the morphology of strained 3D islands in multilayer heteroepitaxial films. The model explains the experimental observation that islands grown in successive layers not only replicate, forming individual island columns, but self-organize to reach a com...Coherent island size; Island shape; Heteroepitaxial films; Strained 3D islands; Heteroepitaxial films1999-03
227 Tiwari, AshutoshShape of the Hanle curve in spin-transport structures in the presence of an ac driveResistance between two ferromagnetic electrodes coupled to a normal channel depends on their relative magnetizations. The spin-dependent component, R, of the resistance changes with magnetic field, B, normal to the directions of magnetizations. In the field of spin transport, this change, R(B), orig...2014-01-01
228 Liu, FengSimple generic method for predicting the effect of strain on surface diffusionWe show, by first-principles calculations, that the effect of external strain on surface diffusion is inherently correlated with the intrinsic surface stress induced by the adatom along its diffusion pathways. We demonstrate a simple generic method for a priori predicting quantitatively how an ext...Surface diffusion; First-principles calculations; Adatoms2001-11
229 Liu, FengSimple theory of the electronic structure: clusters to crystalsA simple scheme based upon a cross between the molecular clusters and the tight-binding theory has been developed to calculate the electronic structure of a large class of systems ranging from molecules to solids. The method is applied to study the variations in the magnetic moments of Fe and Ni for...Clusters; Tight-binding theory; Magnetic moment1988-09
230 Tiwari, AshutoshSingle crystal TaN thin films on TiN/Si heterostructureWe have successfully grown epitaxial cubic (Bl-NaCl structure) tantalum nitride films on Si (100) and (111) substrate using a pulsed laser deposition technique. A thin layer of titanium nitride was used as a buffer medium. We characterized these films using X-ray diffraction, high resolution transmi...Tantalum nitride; Diffusion barriers; Copper diffusion2002
231 Scarpulla, MichaelSnS thin-films by RF sputtering at room temperatureTin monosulfide (SnS) is of interest as a potential solar cell absorber material. We present a preliminary investigation of the effects of sputtering conditions on SnS thin-film structural, optical, and electronic properties. Films were RF sputtered from an SnS target using an argon plasma. Resi...2011
232 Stringfellow, Gerald B.Solid phase immiscibility in GaInNThe large difference in interatomic spacing between GaN and InN is found to give rise to a solid phase miscibility gap. The temperature dependence of the binodal and spinodal lines in the Ga1xInxN system was calculated using a modified valence-force-field model where the lattice is allowed to relax ...Interatomic spacing; Valence-force field; epitaxial growth1996
233 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
234 Liu, FengSpatial and energy distribution of topological edge states in single Bi(111) bilayerBy 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
235 Stringfellow, Gerald B.; Williams, Clayton C.Spatial mapping of ordered and disordered domains of GaInP by near-field scanning optical microscopy and scanning capacitance microscopyImaging of topography, locally induced photoluminescence and Fermi-level pinning in adjacent ordered and disordered domains on a cleaved GaInP sample is performed using a near-field scanning optical microscope and scanning capacitance microscope at room temperature in air. Highly localized photolumi...Gallium Phosphides; Surface Structure; Photoluminescence1996-04-13
236 Stringfellow, Gerald B.Spectroscopic study of surfactant enhanced organometallic vapor phase epitaxy growth of GaInPSamplen s of GaxIn1-xP grown by organometallic vapor phase epitaxy on (001) GaAs substrates by addition of TESb demonstrating a lateral superlattice compositional modulation (CM) have been studied by low temperature polarized photoluminescence (PL), power dependent PL, and photoluminescence excitati...Organometallic vapor; Photoluminescence excitation; Spectroscopy2001
237 Liu, FengStability of doubly charged transition-metal dimersThe spatial dependence of the interaction potentials in doubly charged dimers of transition-metal atoms has been calculated by use of both the tight-binding and the self-consistent-field linear combination of atomic orbitals-molecular orbitals methods. The study reveals an interesting correlation be...Doubly charged; Transition metal dimers; Spatial dependence; Interaction potentials; Metastability1987-11
238 Stringfellow, Gerald B.Step structure and ordering in GaInPPresents information from an experiment on the step structure and ordering in GalnP. Information on the step spacing and degree of order in the epitaxial layers; Details on the experiment; Results from the experiment.Physics; Ordering; Steps1998
239 Stringfellow, Gerald B.Step structure and ordering in Te-doped GaInPThe step structure and CuPt ordering in GaInP layers grown by organometallic vapor phase epitaxy on singular GaAs substrates have been investigated as a function of Te (DETe) doping using atomic force microscopy, and electrical and optical properties measurements. The degree of order decreases for T...Surfaces; Te doping; Bandgap energy1998
240 Stringfellow, Gerald B.Step structure and ordering in Zn-doped GaInPPresents the results of a study of Zinc dopant effects on both step structure and ordering in GaInP in an effort to further clarify the disordering mechanism. Comparison of the results obtained for Zinc with those reported for tellurium; Experiment; Results; Discussion; Conclusion.Gallium Compounds; Zinc; Ordering1999
241 Liu, FengStep-induced magnetic-hysteresis anisotropy in ferromagnetic thin filmsWe investigate the quasistatic magnetic hysteresis of ferromagnetic thin films grown on a vicinal substrate, using Monte Carlo simulations within a two-dimensional XY model. Intrinsic in-plane anisotropy is assigned to surface sites according to their local symmetry. The simulated hysteresis loops s...Magnetic hysteresis; Ferromagnetic thin films; Step-induced2002
242 Liu, FengStep-induced optical anisotropy of vicinal Si(001)It is demonstrated, using reflectance difference spectroscopy, scanning tunneling microscopy, and low-energy electron diffraction, combined with deliberate straining of the surface, that the presence of atomic steps dramatically changes the optical anisotropy of the Si(001) surface. The step-induce...Step-induced; Optical anisotropy; Vicinal Si(001); Electron diffraction; Atomic steps1999-01
243 Liu, FengStrain effect on adatom binding and diffusion in homo- and heteroepitaxies of Si and Ge on (001) SurfacesStrain dependence of adatom binding energies and diffusion barriers in homo- and heteroepitaxies of Si and Ge on s001d surface has been studied using first-principles calculations. In general, Si adatom binding energies and diffusion barriers are larger on Sis001d and Ges001d surfaces than a Ge ada...Strain effect; Adatom binding; Adatom diffusion; Adatoms; Heteroepitaxies; Homoepitaxies; (001) surfaces; Si; Ge2004-10
244 Liu, FengStrain-engineered surface transport in Si(001): complete isolation of the surface state via tensile strainBy combining density functional theory, nonequilibrium Green's function formulism and effective- Hamiltonian approaches, we demonstrate strain-engineered surface transport in Si(001), with the complete isolation of the Si surface states from the bulk bands. Our results show that sufficient tensile s...2013-01-01
245 Tiwari, AshutoshStress-induced tuning of metal-insulator transition in NdNiO3 filmsWe have used the lattice-mismatch epitaxial strain, induced by the constraint of epitaxy, to tune the metal-insulator (M- I) transition temperature of NdNiO3 films grown on Si(100) substrate. Films were integrated with the Si(100) substrate using several combinations of thin buffer layers. A system...NdNiO3; Silicon substrate; Tantalum nitride; Buffer layers; Biaxial strain2002
246 Smith, Grant D.; Bedrov, Dmitro; Borodin, OlegStructural relaxation and dynamic hetrogeneity in a polymer melt at attractive surfacesMolecular dynamics simulations of polymer melts at flat and structured surfaces reveal that, for the former, slow dynamics and increased dynamic heterogeneity for an adsorbed polymer is due to densification of the polymer in a surface layer, while, for the latter, the energy topography of the sur...Polymer melts; Structural relaxation; Dynamic heterogeneity; Attractive surfaces; Surface energy topography; Polymer densification2003-06
247 Tiwari, AshutoshStructural, electrical, and optical characterizations of epitaxial Zn(1-x)Ga(x)O films grown on sapphire (0001) substrateIn this paper we report the structural, electrical, and optical properties of epitaxial Zn1−xGaxO films (x=0-0.05) grown on single crystal sapphire (0001) substrate by pulsed laser deposition technique. Structural and elemental analysis was performed using high-resolution x-ray diffraction (θ-2...Transparent conductive oxides; Gallium2007
248 Scarpulla, MichaelSuppression of hole-mediated ferromagnetism in Ga1-xMnxP by hydrogenWe report the passivation of the Mn acceptors in Ga1−xMnxP upon exposure to a hydrogen plasma. The as-grown films are nonmetallic and ferromagnetic with a Curie temperature of TC=55 K. After hydrogenation the sample resistivity increases by approximately three orders of magnitude at room tempera...Ferromagnetic semiconductors; Hydrogenation2008
249 Liu, FengSuppression of spin polarization in graphene nanoribbon by edge defects and impuritiesWe investigate the effect of edge defects (vacancies) and impurities (substitutional dopants) on the robustness of spin polarization in graphene nanoribbons (GNRs) with zigzag edges by using density-functional-theory calculations. The stability of the spin state and its magnetic moments is found to ...Edge defects; Vacancy; Spin-polarization; Graphene nanoribbon; GNR2008-04
250 Liu, FengSurface mobility difference between Si and Ge and its effect on growth of SiGe alloy films and islandsBased on first-principles calculations of surface diffusion barriers, we show that on a compressive Ge(001) surface the diffusivity of Ge is 102-103 times higher than that of Si in the temperature range of 300 to 900 K, while on a tensile surface, the two diffusivities are comparable. Consequently, ...Surface mobility; SiGe film; Strained thin films; Surface diffusion barriers2006-01
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