Berlin 2012 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 13: Computational Materials Modelling III - Alloys

MM 13.4: Talk

Monday, March 26, 2012, 16:30–16:45, TC 006

Effects of In concentration in CuGa_1−xIn_xSe₂: a first-principles study — •Rolando Saniz, Dirk Lamoen, and Bart Partoens — Universiteit Antwerpen, Antwerpen, Belgium

Compounds of the family of CuGa_1−xIn_xSe₂ alloys are of great current interest for the development of better absorbers for photovoltaic applications. To advance our understanding of the effects of alloying ratio, x, we carried out a state-of-the-art hybrid functional study of the structural and electronic properties of these materials for a series of x values. In contrast to previous theoretical results, we find that (i) the structural changes induced by increasing In content do not comply to Vegard’s law, resulting in fact in a lowering of the symmetry of the system for intermediate In concentrations; (ii) as a function of x, the fundamental band gap does not follow a quadratic curve defined by a simple “bowing parameter”; (iii) the mixing enthalpies are very low and do not suggest any significant phase separation at finite temperatures.