Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 15: Focus Session: Crystalline n-type semiconducting oxides - SnO2, Ga2O3, and In2O3 for novel devices (HL, jointly with O)
HL 15.10: Talk
Monday, March 11, 2013, 18:45–19:00, H2
Surface and bulk derived in-gap states of In2O3 single crystals — •Dorothee Braun1, Valentina Scherer1, Christoph Janowitz1, Zbigniew Galazka2, 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
The influence of intrinsic point defects on the electronic structure of n-type In2O3 single crystals grown by two methods, namely chemical vapor transport (CVT) and melt growth, was examined by two different spectroscopic methods. First, with scanning tunneling spectroscopy (STS), a very surface sensitive technique for measuring the local density of states (LDOS). So far not resolved states within the fundamental band gap have been observed. The gap states have been studied for different crystals and after several temper treatments in oxygen. Second, low-energy angular-resolved photoemission spectroscopy (low-e ARPES) at hν=9 eV photon energy has been used to investigate the gap states in the bulk. In contrast to conventional ARPES at typical VUV we were now able to resolve individual emissions of the gap states as well as their momentum dependence. The spectroscopic results will be compared to state of the art DFT-calculations revealing the origin of the gap states in In2O3 to be due to oxygen vacancies as well as indium and oxygen interstitials.