Transport and angular resolved photoemission measurements of the electronic properties of In 2O 3 bulk single crystals

Applied Physics Letters (Impact Factor: 3.52). 05/2012; 100(21):212108. DOI: 10.1063/1.4719665

ABSTRACT High quality In 2O 3 single crystals of bcc structure were grown by chemical vapour transport. The temperature dependence of resistivity, Hall constant, and mobility yielded an electron density of n = 1.3 × 10 19*cm -3. The transport properties showed characteristics best describable by the degenerate semiconductor model. The crystals were additionally investigated by high resolution angular resolved photoelectron spectroscopy (ARPES). Emission from the valence band and the partially filled conduction band at the Γ point yielded a direct bandgap of (2.7 ± 0.1)eV. The partially filled conduction band furthermore enabled the determination of its three dimensional Fermi surface and the effective masses m * by ARPES.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Angle-resolved photoemission spectroscopy reveals the presence of a two-dimensional electron gas at the surface of In_{2}O_{3}(111). Quantized subband states arise within a confining potential well associated with surface electron accumulation. Coupled Poisson-Schrödinger calculations suggest that downward band bending for the conduction band must be much bigger than band bending in the valence band. Surface oxygen vacancies acting as doubly ionized shallow donors are shown to provide the free electrons within this accumulation layer. Identification of the origin of electron accumulation in transparent conducting oxides has significant implications in the realization of devices based on these compounds.
    Physical Review Letters 02/2013; 110(5):056803. · 7.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new 5-m normal-incidence monochromator at the third generation synchrotron source BESSY II of the Helmholz-Zentrum Berlin (HZB) has been constructed with the emphasis on angle-resolved photoelectron spectroscopy with high-resolution and at low energy utilizing photons from 5 eV to 40 eV. Optical design and preliminary performance results of the beamline and the photoemission endstation are presented and match the design goals.
    Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2012; 693:160–165. · 1.14 Impact Factor