Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 30: Focussed session: Transparent conductive oxides II (jointly with HL, DS)

O 30.1: Topical Talk

Dienstag, 15. März 2011, 11:15–11:45, WIL B122

Experimental Electronic Structure of In₂O₃ and Ga₂O₃ — •Christoph Janowitz — Brandenburgische Technische Universität Cottbus — Humboldt Universität zu Berlin, Institut für Physik

Transparent conducting oxides (TCO’s) pose a number of serious challenges. Besides the strive for high quality single crystals and thin films their application has to be preceded by a thorough understanding of their peculiar electronic structure. It is of fundamental interest to understand why materials transparent up to the UV spectral regime behave also as conductors. In this talk two binary oxides -In₂O₃ and Ga₂O₃ from the group of TCO’s showing the smallest respectively largest optical gap- will be explored experimentally. The investigations on the electronic structure were performed on high quality n-type single crystals showing carrier densities of  10¹⁹ cm⁻³ (In₂O₃) and  10¹⁷ cm⁻³ (Ga₂O₃). Subjects addressed are the determination of the band structure along the high symmetry directions, effective masses and fundamental gap by angular resolved photoemission (ARPES). Also by resonant ARPES and a combination of X-ray photoemission and X-ray absorption complementary information on the orbital character of the valence- and conduction band regime and on the band gap are obtained. The observations are discussed by reference to calculations of the electronic structure and models for the conductivity mechanism.