The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform

Lichyong Che - One of the best experts on this subject based on the ideXlab platform.

  • thickness dependent binding Energy Shift in few layer mos2 grown by chemical vapor deposition
    ACS Applied Materials & Interfaces, 2016
    Co-Authors: Rueisa Che, Tsuchi Chou, Yihsi Lee, Yangfang Che, Kueihsie Che, Lichyong Che
    Abstract:

    The thickness-dependent surface states of MoS2 thin films grown by the chemical vapor deposition process on the SiO2–Si substrates are investigated by X-ray photoelectron spectroscopy. Raman and high-resolution transmission electron microscopy suggest the thicknesses of MoS2 films to be ranging from 3 to 10 layers. Both the core levels and valence band edges of MoS2 Shift downward ∼0.2 eV as the film thickness increases, which can be ascribed to the Fermi level variations resulting from the surface states and bulk defects. Grainy features observed from the atomic force microscopy topographies, and sulfur-vacancy-induced defect states illustrated at the valence band spectra imply the generation of surface states that causes the downward band bending at the n-type MoS2 surface. Bulk defects in thick MoS2 may also influence the Fermi level oppositely compared to the surface states. When Au contacts with our MoS2 thin films, the Fermi level downShifts and the binding Energy reduces due to the hole-doping char...

Roger Aulombard - One of the best experts on this subject based on the ideXlab platform.

  • critical layer thickness in mocvd grown ingaasgaas strained quantum wells
    Materials Science and Engineering B-advanced Functional Solid-state Materials, 1995
    Co-Authors: Xiaobo Zhang, Olivier Briot, Roger Aulombard
    Abstract:

    Abstract A series of In0.14Ga0.86AsGaAs quantum well structures have been grown by metal organic chemical vapor deposition (MOCVD). The measured dependence of photoluminescence (PL) energies on well width is compared with calculation. By the Energy Shift, line width and intensity change of PL spectroscopy, critical layer thickness has been identified. The critical layer thickness obtained for MOCVD grown material was found in agreement with theoretical value, but is smaller than molecular beam epitaxy grown ones.

  • critical layer thickness in metal organic chemical vapor deposition grown ingaas gaas strained quantum wells
    Journal of Applied Physics, 1995
    Co-Authors: Xiaobo Zhang, Olivier Briot, Roger Aulombard
    Abstract:

    A series of In0.14Ga0.86As/GaAs quantum well structures have been grown by metal organic chemical vapor deposition (MOCVD). The measured dependence of photoluminescence (PL) energies on well width is compared with calculation. By the Energy Shift, line width, and intensity change of PL spectroscopy, critical layer thickness has been identified. The critical layer thickness obtained for MOCVD‐grown material was found in agreement with theoretical value, but is smaller than material grown by molecular beam epitaxy.

Miguel Pruneda - One of the best experts on this subject based on the ideXlab platform.

  • real time td dft simulations in dye sensitized solar cells the electronic absorption spectrum of alizarin supported on tio2 nanoclusters
    Journal of Chemical Theory and Computation, 2010
    Co-Authors: Rocio Sanchezdearmas, Jaime Oviedo Lopez, Miguel A Sanmiguel, Javier Fdez Sanz, Pablo Ordejon, Miguel Pruneda
    Abstract:

    The structural and electronic properties of the alizarin dye supported on TiO2 nanoclusters have been examined by means of time-dependent density-functional (TD-DFT) calculations performed in the time-domain framework. The calculated electronic absorption spectrum of free alizarin shows a first band centered at 2.67 eV that upon adsorption features a red Shift by 0.31 eV, in agreement with both experimental and previous theoretical work. This red Shift arises from a relative stabilization of the dye LUMO when adsorbed. To analyze the dependence of the electronic properties of the dye-support couple on the size of metal-oxide nanoparticles, different models of (TiO2)n nanoclusters have been used (with n = 1, 2, 3, 6, 9, 15, and 38). As a conclusion, the minimal model is good enough to theoretically reproduce the main feature in the spectrum (i.e., the Energy Shift of the main band upon binding to TiO2). However, it fails in creating intermediate states which could play a significant role under real experim...

J A Fernandezbaca - One of the best experts on this subject based on the ideXlab platform.

  • high resolution phonon Energy Shift measurements with the inelastic neutron spin echo technique
    Journal of Applied Crystallography, 2019
    Co-Authors: Jiazhou She, S R Parnell, A Thale, M Matsuda, T Kelle, Olivie Delaire, J A Fernandezbaca
    Abstract:

    The Energy resolution of the conventional way of measuring a small change in a phonon dispersion curve using neutron scattering is restricted by the relatively coarse intrinsic resolution ellipsoid of the neutron triple-axis spectrometer (TAS). By implementing inelastic neutron spin echo on the host TAS using the Larmor precession of the neutron spin, the Energy resolution of such measurements can be further improved without reducing the resolution ellipsoid. Measurements of the temperature-dependent phonon Energy change are demonstrated using superconducting magnetic Wollaston prisms at the HB-1 instrument of the High-Flux Isotope Reactor at Oak Ridge National Laboratory, and the achievable resolution is <10 µeV.

P Fumagalli - One of the best experts on this subject based on the ideXlab platform.

  • observation of a hole size dependent Energy Shift of the surface plasmon resonance in ni antidot thin films
    Applied Physics Letters, 2015
    Co-Authors: Hui Fang, Lanca Caballero, Eser Meti Akinoglu, Th E Papaioannou, Antonio Garciamarti, Juan Carlos Cuevas, Michael Giersig, P Fumagalli
    Abstract:

    A combined experimental and theoretical study of the magneto-optic properties of a series of nickel antidot thin films is presented. The hole diameter varies from 869 down to 636 nm, while the lattice periodicity is fixed at 920 nm. This results in an overall increase of the polar Kerr rotation with decreasing hole diameter due to the increasing surface coverage with nickel. In addition, at photon energies of 2.7 and 3.3 eV, where surface-plasmon excitations are expected, we observe distinct features in the polar Kerr rotation not present in continuous nickel films. The spectral position of the peaks exhibits a red Shift with decreasing hole size. This is explained within the context of an effective medium theory by a change in the effective dielectric function of the Ni thin films.