Dresden 2011 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 9: Joint Focussed Session: Transparent Conductive Oxides I
HL 9.4: Vortrag
Montag, 14. März 2011, 12:45–13:00, WIL A317
The electronic properties of β -Ga2O3 — •Mansour Mohamed1, Christoph Janowitz1, Isaak Unger1, Zbigniew Galazka2, Justin R. Weber3, and Recardo Manzke1 — 1Humboldt-Universität zu Berlin, Institut für Physik, Newtonstr. 15, 12489 Berlin, Germany — 2Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489 Berlin, Germany — 3Materials Department, University of California, Santa Barbara, California 93106-5050, USA
Ga2O3 belongs to the group of transparent conducting oxides (TCOs) with a wide band gap. It exhibits the largest band gap with Eg = 4.9 eV [1] and thus a unique transparency from the visible into the UV region. The n-type high-quality β -Ga2O3 single crystals were grown by the Czochralski method [2]. The crystals were characterized by different techniques (LEED, STM). The experimental valence band structure of β-Ga2O3 was determined by high-resolution angle-resolved photoelectron spectroscopy (ARPES) utilizing synchrotron radiation. The calculated band structure was determined using advanced density functional theory (DFT) calculations employing hybrid functionals and projector augmented wave (PAW) potentials. From theory, we obtained a direct band gap of 4.87 eV and a slightly smaller indirect band gap of 4.83 eV, with the valence-band maximum (VBM) located slightly away from the M symmetry point. The experimental band structure of β-Ga2O3 is compared and discussed with the theoretical calculations. The effect of changing the temperature from 300K to 20K on the experimental band structure β-Ga2O3 was studied.