Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 96: GaN: Growth and doping

HL 96.1: Talk

Friday, March 15, 2013, 09:30–09:45, H15

Dependence of band gap bowing of epitaxial In_xGa_1−xN on composition, strain and ordering effects by first-principles calculations — •Ying Cui, Sangheon Lee, Gerard Leyson, Christoph Freysoldt, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, 40627 Düsseldorf

The band gap of In_xGa_1−xN alloys does not only depend on the In composition, but also on the strain state and the ordering of In atoms. We performed a theoretical study to disentangle the different effects. According to our results, the band gaps of In_xGa_1−xN alloys show parabolic behavior in compressive regions and linear dependence in the tensile regions. We further find a universal bowing behavior in In_xGa_1−xN alloys for the whole In content range under constant relative strain. Inhomogeneous In distributions lead to a narrower band gap, but are energetically unfavorable. Based on the calculated results, an interpolating form for the band bap as a function of ordering, biaxial strain and chemical content for In_xGa_1−xN alloys is suggested. Our results provide guidance to determine the band gaps of In_xGa_1−xN alloys under real experiment conditions.