Regensburg 2007 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 13: Poster 1

HL 13.16: Poster

Montag, 26. März 2007, 15:00–17:30, Poster A

The band structure of indium oxide: indirect vs. direct band gap — Paul Erhart, •Péter Ágoston, Andreas Klein, and Karsten Albe — Technische Universität Darmstadt, Institut für Materialwissenschaft, Petersenstraße 23, 64287 Darmstadt

The nature of the band gap of indium oxide is still a matter of debate. Based on optical measurements the presence of an indirect band gap has been suggested, which is 0.9 to 1.1 eV smaller than the direct band gap at the Γ-point. This could be caused by strong mixing of O-2p and In-4d orbitals off Γ. We have performed extensive density functional theory calculations using the LDA+U and GGA+U method to elucidate the contribution of the In-4d states and the effect of spin-orbit coupling on the valence band structure. Although an indirect band gap is obtained the energy difference between the overall valence band maximum and the highest occupied level at the Γ-point is less than 50 meV. It is concluded that the experimental observation cannot be related to the electronic structure of the bulk material.