Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 29: III-V Semiconductors I (mainly Nitrides)

HL 29.5: Talk

Tuesday, March 27, 2012, 10:30–10:45, EW 201

Understanding and controlling In incorporation on InGaN surfaces: An ab initio approach — •Andrew Duff, Liverios Lymperakis, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straβe 1, 40237 Düsseldorf, Germany.

A first step in achieving full control on the growth and properties of {0001} (N-polar) InGaN surfaces is to gather a fundamental understanding of the relevant atomistic surface processes as well as to identify and investigate the differences in the growth of the N-polar face compared to the {0001} (Ga-polar) face. In this work, the incorporation of In into N- and Ga-polar surfaces is investigated using density functional theory (DFT) calculations. Total energies for an extensive range of reconstructions on the technologically relevant Ga-polar and N-polar surfaces are calculated and surface phase diagrams are constructed showing the most stable structures as a function of growth conditions. A substantially stronger binding for In adlayer/s and In adlayer/s with sub-surface In is found for N-polar compared to Ga-polar. Kinetic DFT calculations are also performed to address the competing effect of In segregation, with the surface segregation effect found to be weakest for the N-polar surface. Based on these results, the mechanisms of In incorporation, In segregation and also the self surfactant effect will be discussed in detail.