UScholar Works
 
Filters: Department: "Materials Science & Engineering" School Or College: "College of Engineering" Collection: "ir_uspace"
226 - 250 of 288
Number of results to display per page
CreatorTitleDescriptionSubjectDate
226 Liu, FengFirst-principles study of electronic properties of biaxially strained silicon: effects on charge carrier mobilityUsing first-principles method, we calculate the electronic band structure of biaxially strained silicon, from which we analyze the change in electron and hole effective mass as a function of strain and determine the mobility of electrons and holes in the biaxially strained silicon based on Boltzmann...Biaxially strained silicon; Boltzmann transport theory2008-12
227 Scarpulla, MichaelCompensation-dependent in-plane magnetization reversal processes in Ga1-xMnxP1-ySyWe report the effect of dilute alloying of the anion sublattice with S on the in-plane uniaxial magnetic anisotropy and magnetization reversal process in Ga1−xMnxP as measured by both ferromagnetic resonance (FMR) spectroscopy and superconducting quantum interference device (SQUID) magnetometry. ...Ferromagnetic semiconductors; Nonmagnetic compensation2008-12
228 Scarpulla, MichaelBandgap and band offsets determination of semiconductor heterostructures using three-terminal ballistic carrier spectroscopyAmong the most important properties of semiconductors are their bandgaps and how the total bandgap difference distributes between the conduction band offset ΔEC and the valence band offset ΔEV at the heterojunction (HJ) interface between two semiconductors. Understanding such properties is crucial...Bandgaps; Band offsets; Gallium arsenide2009
229 Bedrov, DmitroMolecular dynamics simulation study of the pressure-volume-temperature behavior of polymers under high pressureIsothermal compression of poly (dimethylsiloxane), 1,4-poly(butadiene), and a model Estane® (in both pure form and a nitroplasticized composition similar to PBX-9501 binder) at pressures up to 100 kbars has been studied using atomistic molecular dynamics (MD) simulations. Comparison of predicted co...2009
230 Scarpulla, MichaelFerromagnetic resonance investigation of magnetic anisotropy in Ga1-xMnxAs synthesized by ion implantation and pulsed laser meltingA systematic investigation of ferromagnetic resonance (FMR) was carried out on Ga1−xMnxAs layers synthesized by Mn ion implantation into GaAs followed by pulsed laser melting. Angular and temperature dependences of FMR were measured on layers prepared on GaAs (001), (110), and (311) surfaces. The ...Magnetic anisotropy; Ga1−xMnxAs; Gallium manganese arsenide2009-12
231 Scarpulla, MichaelEnhanced absorption in optically thin solar cells by scattering from embedded dielectric nanoparticlesAbstract: We present a concept for improving the efficiency of thin-film solar cells via scattering from dielectric particles. The particles are embedded directly within the semiconductor absorber material with sizes on the order of one wavelength. Importantly, this geometry is fully compatible wit...2010
232 Scarpulla, MichaelInvestigating sputtered Cu2Si1-xSnxS3 (CSTS) for earth abundant thin film photovoltaicsThis study investigates the synthesis of chalcopyrite Cu2Si1-xSnxS3 (CSTS) thin films for photovoltaic solar cell absorber layers. Preliminary results indicate that layered sputtering of Cu, Sn, and Si followed by annealing in a sulfur atmosphere at 500⁰C does not provide adequate mixing or sulfu...2010
233 Scarpulla, MichaelHeat flow model for pulsed laser melting and rapid solidification of ion implanted GaAsIn order to further understand the pulsed-laser melting (PLM) of Mn and N implanted GaAs, which we have used to synthesize thin films of the ferromagnetic semiconductor Ga1−xMnxAs and the highly mismatched alloy GaNxAs1−x, we have simulated PLM of amorphous (a-) and crystalline (c-) GaAs. We pre...2010
234 Chaudhuri, Reaz A.Interlaminar shear stresses around an internal part-through hole in a stretched laminated composite plateThe equilibrium/compatibility method, which is a semi-analytical post-processing method, is employed for computation of hitherto unavailable through-thickness variation of interlaminar (transverse) shear stresses in the vicinity of the bi-layer interface circumferential re-entrant corner line of an...2010-03
235 Chaudhuri, Reaz A.Transverse shear stress distribution through thickness near an internal part-through elliptical hole in a stretched plateA semi-analytical post-processing method, termed the equilibrium/compatibility method here, is used for computation of hitherto unavailable through-thickness variation of transverse shear stresses in the vicinity of the circumferential re-entrant corner line of an internal part-through elliptical ...2010-03
236 Chaudhuri, Reaz A.Three-dimensional singular stress field at the front of a crack and lattice crack deviation (LCD) in a cubic single crystal plateA novel eigenfunction expansion technique, based in part on separation of the thickness variable, is developed to derive three-dimensional asymptotic stress fields in the vicinity of the front of a semi-infinite through-crack weakening an infinite plate made of a homogeneous cubic single crystal. C...2010-05-12
237 Scarpulla, MichaelProbing semiconductor band structures and heterojunction interface properties with ballistic carrier emission: GaAs/AlxGa1-xAs as a model systemUtilizing 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
238 Chaudhuri, Reaz A.On three-dimensional singular stress/residual stress fields at the front of a crack/anticrack in an orthotropic/orthorhombic plate under anti-plane shear loadingA novel eigenfunction expansion technique, based in part on separation of the thickness-variable, is developed to derive three-dimensional asymptotic stress field in the vicinity of the front of a semi-infinite through-thickness crack/anticrack weakening/reinforcing an infinite orthotropic/orthorhom...2010-07
239 Scarpulla, MichaelExact field solution to guided wave progagation in lossy thin filmsWave guidance is an important aspect of light trapping in thin film photovoltaics making it important to properly model the effects of loss on the field profiles. This paper derives the full-field solution for electromagnetic wave propagation in a symmetric dielectric slab with finite absorption. ...2011
240 Scarpulla, MichaelGrain size and texture of Cu2ZnSnS4 thin films synthesized by co-sputtering binary sulfides and annealing: effects of processing conditions and sodiumWe investigate the synthesis of kesterite Cu2ZnSnS4 (CZTS) polycrystalline thin films using cosputtering from binary sulfide targets followed by annealing in sulfur vapor at 500 ?C to 650 ?C. The films are the kesterite CZTS phase as indicated by x-ray diffraction, Raman scattering, and optical abso...2011
241 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
242 Scarpulla, MichaelEnhanced light absorption in thin-film silicon solar cells by scattering from Embedded Dielectric NanoparticlesWe investigate the light-trapping effects of dielectric nanoparticles embedded within the active semiconductor layer of a thin-film solar cell. The baseline model consists of a 1.0 μm slab of crystalline silicon on an aluminum back contact topped with a 75 nm Si3N4 anti-reflective coating. Using fi...2011-01-01
243 Scarpulla, MichaelPulsed laser processing of electrodeposited CuInSe2 photovoltaic absorber thin filmsIn this report we investigate the effects of pulsed laser annealing (PLA) on both as-electrodeposited (ED) and electrodeposited-furnace annealed (EDA) CuInSe2 (CIS) samples by varying the laser fluence (J/cm2) and number of pulses. Results for as-ED samples indicate that liquid CIS-phase formation d...2011-01-01
244 Scarpulla, MichaelElectron backscatter diffraction and photoluminescence of sputtered CdTe thin filmsElectron backscatter diffraction (EBSD) has been used to characterize the grain size, grain boundary structure, and texture of sputtered CdTe at varying deposition pressures before and after CdCl2 treatment in order to correlate performance with film microstructure. It is known that twin boundaries ...2011-01-01
245 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
246 Ostafin, AgnesNanomedicine making headway across the blood brain barrierNanotechnological advances implemented by nanomedicine have allowed significant development of imaging strategies, therapeutics and theranostics for many severe and life threatening diseases such as brain tumors, Alzheimer's disease, Parkinson's disease and other neurological disorders. The Blood-Br...2012-01-01
247 Liu, FengTopological and electronic transitions in a Sb(111) nanofilm: the interplay between quantum confinement and surface effectWhen the dimension of a solid structure is reduced, there will be two emerging effects, quantum confinement and surface effect, which dominate at nanoscale. Based on first-principles calculations, we demonstrate that due to an intriguing interplay between these two dominating effects, the topologica...2012-01-01
248 Liu, FengElectronic strengthening of graphene by charge dopingGraphene is known as the strongest 2D material in nature, yet we show that moderate charge doping of either electrons or holes can further enhance its ideal strength by up to 17%, based on first-principles calculations. This unusual electronic enhancement, versus conventional structural enhancement,...2012-01-01
249 Tiwari, AshutoshGarnet-type Li7La3Zr2O12 electrolyte prepared by a solution-based technique for lithium ion batteryHigh quality garnet-type Li7La3Zr2O12 solid electrolyte was synthesized using a solution-based technique. The electrolyte pellets were sintered at 900 oC, resulting in tetragonal phase, which then transformed to cubic phase after annealing at 1230 oC. The ionic conductivity of both phases was studie...2012-01-01
250 Liu, FengInterplay between quantum size effect and strain effect on growth of nanoscale metal thin filmsWe develop a theoretical framework to investigate the interplay between the quantum size effect (QSE) and strain effect on the stability of metal nanofilms. The QSE and strain effect are shown to be coupled through the concept of quantum electronic stress. First-principles calculations reveal large ...2012-01-01
226 - 250 of 288