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26 Liu, FengComputational designing of carbon nanotube electromechanical pressure sensorsWe investigate electronic transport properties of single-walled carbon nanotubes (SWNT's) under hydrostatic pressure, using first-principles quantum transport calculations aided by molecular-dynamics simulation and continuum mechanics analysis. We demonstrate a pressure-induced metal-to-semiconduc...Carbon nanotubes; Computational designing; Pressure sensors; Electronic transport2004-04
27 Liu, FengConfining P diffusion in Si by an As-doped barrier layerThe miniaturization of Si-based devices requires control of doping profile, which makes the understanding of dopant interaction and diffusion in Si critical. The authors have studied the effect of As doping on P diffusion in Si using first-principles calculations. The authors found a form of As-vaca...P diffusion; Silicon; Arsenic doping; As-doped barrier; Diffusion control2007
28 Smith, Grant D.Conformational properties of poly(vinylidene fluoride). A quantum chemistry study of model compoundsThe molecular geometries and conformational energies of model molecules of poly(vinylidene fluoride) (PVDF) have been determined from high-level quantum chemistry calculations and have been used in parametrization of a six-state rotational isomeric state (RIS) model for PVDF. The model molecules inv...Poly(vinylidene fluoride); PVDF; Conformational properties1999
29 Stringfellow, Gerald B.Control and characterization of ordering in GaInPGae,,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 spectroscopy1993-06-28
30 Stringfellow, Gerald B.Control of ordering in Ga0.5In0.5P using growth temperatureThe kinetic processes leading to ordering in Gas,, In o.4P8 have been studied by observing the effects of substrate misorientation (O-9), growth rate (0.1-0.5), and substrate temperature (570- 670 "C) during growth. The ordered structure and degree of ordering are determined using transmission elec...Ordering Structure; Growth Temprature; Growth Rate1994
31 Tiwari, AshutoshCopper diffusion characteristics in single crystal and polycrystalline TaNTaN has become a very promising diffusion barrier material for Cu interconnections, due to the high thermal stability requirement and thickness limitation for next generation ULSI devices. TaN has a variety of phases and Cu diffusion characteristics vary with different phases and microstructures. We...Diffusion barriers; Copper diffusion; Tantalum nitride2003
32 Tiwari, AshutoshCopper diffusion characteristics in single-crystal and polycrystalline TaNWe have investigated the diffusivity of copper in single-crystal (NaCl-structured) and polycrystalline TaN thin films grown by pulsed-laser deposition. Polycrystalline TaN films were grown directly on Si(100), while single-crystal films were grown with TiN buffer layers. Both poly- and single-crysta...Diffusion barriers; Copper diffusion; Tantalum nitride2002
33 Stringfellow, Gerald B.Correlation between surface structure and ordering in GaInPGa and In atoms in Ga0.52In0.48P layers spontaneously segregate to form alternating In- and Ga-rich {111} monolayers during organometallic vapor phase epitaxial (OMVPE) growth on (001) oriented GaAs substrates, thus forming the CuPt ordered structure. This ordering phenomenon is believed to be drive...Transformations; Absorbtion spectra; Surface Properties1996
34 Liu, FengCoulomb sink: a novel Coulomb effect on coarsening of metal nanoclusters on semiconductor surfacesWe propose the concept of a ‘‘Coulomb sink'' to elucidate the effect of Coulomb charging on coarsening of metal mesas grown on semiconductor surfaces.We show that a charged mesa, due to its reduced chemical potential, acts as a Coulomb sink and grows at the expense of neighboring neutral mesas. ...Coulomb sink; Coulomb effect; Metal nanoclusters; Semiconductor surface; Pb mesas2004-09
35 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
36 Liu, FengCritical epinucleation on reconstructured surfaces and first-principle calculation of homonucleation on Si(100)We introduce the concept of ‘‘critical epinucleation'' to distinguish nucleation on surfaces with and without reconstruction. On a reconstructed surface, the critical classical nucleus is stable against dissociation, but may not yet break the underlying surface reconstruction. Consequently, ther...Critical epinucleation; First-principle calculation; Homonucleation; Si(100); Islands2005-09
37 Tiwari, AshutoshCuBO2: a p-type transparent oxideThe authors report the synthesis of CuBO2, a p-type transparent oxide belonging to Cu-delafossite family. High quality thin films of CuBO2 were deposited on c-plane sapphire substrates by pulsed laser deposition technique. Detailed structural, optical, and electrical characterizations on these films...Transparent conducting oxides; Delafossite series; CuBO22007
38 Stringfellow, Gerald B.Deep electron traps in organometallic vapor phase grown AlGaAsDeep electron traps have been studied by means of deep level transient spectrosocopy in type nominally undoped and interntionally te doped Al Ga As epitaxial layers which were grown by vapor phase epitaxy from organometallic compounds (OMVPE). Three main deep electron levels are present in undoped m...Vapor phase epitaxy; Shallow impurity identity; Optoelectronic device performance1980
39 Scarpulla, MichaelDetection of ZnS phases in CZTS thin-films by EXAFSCopper zinc tin sulfide (CZTS) is a promising Earthabundant thin-film solar cell material; it has an appropriate band gap of ~1.45 eV and a high absorption coefficient. The most efficient CZTS cells tend to be slightly Zn-rich and Cu-poor. However, growing Zn-rich CZTS films can sometimes result in ...2011-01-01
40 Liu, FengDetermination of the Ehrlich-Schwoebel barrier in epitaxial growth of thin filmsWe demonstrate an approach for determining the "effective" Ehrlich-Schwoebel (ES) step-edge barrier, an important kinetic constant to control the interlayer mass transport in epitaxial growth of thin films. The approach exploits the rate difference between the growth and/or decay of an adatom and a...Ehrlich-Schwoebel barrier; Epitaxial growth; Step-edge barrier; Adatoms2006-11
41 Scarpulla, MichaelDetermination of the infrared complex magnetoconductivity tensor in itinerant ferromagnets from Faraday and Kerr measurementsWe present measurement and analysis techniques that allow the complete complex magnetoconductivity tensor to be determined from midinfrared (11-1.6 μm; 100-800 meV) measurements of the complex Faraday (θF) and Kerr (θK) angles. Since this approach involves measurement of the geometry (orientati...Magnetoconductivity tensor; Ferromagnets2007-06
42 Liu, FengDetermining the adsorptive and catalytic properties of strained metal surfaces using adsorption-induced stressWe demonstrate a model for determining the adsorptive and catalytic properties of strained metal surfaces based on linear elastic theory, using first-principles calculations of CO adsorption on Au and K surfaces and CO dissociation on Ru surface. The model involves a single calculation of the adsorp...Strained metal surfaces; Adsorption-induced stress; Adsorptive properties; Catalytic properties2004
43 Scarpulla, MichaelDiluted II-VI oxide semiconductors with multiple band gapsWe report the realization of a new mult-band-gap semiconductor. Zn1-yMnyOxTe1-x alloys have been synthesized using the combination of oxygen ion implantation and pulsed laser melting. Incorporation of small quantities of isovalent oxygen leads to the formation of a narrow, oxygen-derived band of ...Highly mismatched alloys; Zinc telluride2003-12
44 Stringfellow, Gerald B.Dislocations in GaAs17-xPxDislocations, their origins, and their effects on photoluminescence efficiency have been studied in GaAs1-xPx single crystals grown by vapor phase epitaxy. Dislocations were observed using etch pit, optical-transmission microscopy, and x-ray topography techniques. Two types of dislocations are grown...Photoluminescence efficiency; Growth mechanism; Optical transmission microscopy1969
45 Stringfellow, Gerald B.Doping studies of Ga0.5In0.5P organometallic vapor-phase epitaxyPresents doping studies of gallium[sub0.5] indium[sub0.5] phosphorus organometallic vapor-phase epitaxy. Distribution coefficient of indium; Description of growth conditions; Case of poor growth morphology for gallium[sub0.5] indium[sub0.5] phosphorus.Phosphorus; Gallium; Doping1986
46 Scarpulla, MichaelEffect of film thickness on the incorporation of Mn interstitials in Ga1-xMnxAsWe 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 arsenide2005
47 Stringfellow, Gerald B.Effect of growth rate on step structure and ordering in GaInPCuPt ordering is widely observed in GaInP epitaxial layers grown by organometallic vapor phase epitaxy. The formation of this spontaneously ordered structure during epitaxial growth is intimately related to the atomic-scale physical processes occurring on the surface, specifically surface reconst...Atomic force microscopy; Organometallic vapor phase; Crystallographic plane1997
48 Stringfellow, Gerald B.Effect of oxygen incorporation in semi-insulating (AlxGa1-x)yIn1-yPDiscusses a study conducted on oxygen-doped, semi-insulating layers of (aluminum-gallium) indium phosphide grown on gallium arsenide using organometallic vapor phase epitaxy. Effect of oxygen doping on semi-insulating layers of the substance; Secondary-ion mass spectrometry measurements; Measured co...Inactive interstitial atoms; Energy-dispersive spectoscopy; intentional oxygen1992
49 Liu, FengEffect of size and dimensionality on the magnetic moment of transition metalsThe effect of size and dimensionality on the magnetic moments of Fe, Co, and Ni have been studied theoretically by confining the atoms t o various structural forms such as chains,surfaces, and thin films. The size of these systems is controlled by limiting t h e number of atoms. A new first-princip...Magnetic moment; Dimensionality; Size effects; Fe; Co; Ni1990
50 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
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