Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 21: Poster IB (Oxide semiconductors; II-VI and group IV semiconductors; Nanotubes and Buckyballs)
HL 21.3: Poster
Montag, 16. März 2015, 15:00–20:00, Poster B
Ohmic contacts to In2O3 single crystals — •Maryam Nazarzadehmoafi1, Mattia Mulazzi1, Christoph Janowitz1, Stephan Machulik1, Zbigniew Galazka2, and Recardo Manzke1 — 1Institut für Physik, Humboldt Universität zu Berlin, Newtonstraße 15, 12489 Berlin, Germany — 2Leibniz Institut für Kristallzüchtung, Max Born Str. 2, 12489 Berlin, Germany
It is known that the barrier formation at the interface between metals and ionic semiconductors usually follows the Schottky-Mott rule. In contrast, this model fails for the several metal-In2O3 interfaces, and this is commonly attributed to an electron accumulation layer at the surface of In2O3, believed to prevent the Schottky contact formation. In order to have a deeper insight into the metal-In2O3 contacts, the barrier heights of In and Cu on the melt-grown In2O3(111) single crystals were studied by means of ARPES at room temperature (RT) and low temperature (LT). The growth of Copper on In2O3 (111) is ordered and homogenous at RT, as suggested by the presence of a distinct surface state for thick Cu films. In the case of Indium, we observed an electronic state near the Fermi level at small coverages, blurring out for increasing the metal thicknesses, what is a signature of an interface state. The ohmic behavior of both interfaces is evident at RT and LT for both metals, contrary to the prediction of the Schottky-Mott rule, with a stronger discrepancy for Cu/In2O3. We interpret the results in terms of surface electron and hole-doping of the semiconductor and with the presence of a significant density of electronic states within the band gap that is responsible for the reduction of the barrier height.