Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 31: III-V-Compounds: Nitrides
HL 31.1: Talk
Tuesday, March 15, 2011, 10:15–10:30, POT 51
Direct measurement of the band gap and Fermi level position at InN(1120) — •Philipp Ebert1, Sarah Schaafhausen1, Andrea Lenz2, Aizhan Sabitova1, Lena Ivanova2, Mario Dähne2, Yu-Liang Hong3, Shangjr Gwo3, and Holger Eisele2 — 1Institut für Festkörperfoschung, Forschungszentrum Jülich GmbH, 52425 Jülich — 2Institut für Festkörperphysik, Technische Universität Berlin, 10623 Berlin — 3Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan
A non-polar stoichiometric InN(1120) surface freshly cleaved inside UHV was investigated by scanning tunneling microscopy and spectroscopy. Due to the absence of intrinsic surface states in the band gap, scanning tunneling spectroscopy yields directly the fundamental bulk band gap EG=0.7 +/- 0.1 eV. The Fermi energy is pinned 0.3 eV below the conduction band minimum due to cleavage induced defect states. Thus, intrinsic electron accumulation can be excluded for this surface. Electron accumulation is rather an extrinsic effect due to surface contamination or material decomposition, but not an intrinsic material property of InN.