Berlin 2012 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 51: Computational Materials Modelling VII - Oxides

MM 51.3: Talk

Thursday, March 29, 2012, 12:15–12:30, TC 006

Thermodynamic stability of Cd₂SnO₄ and Zn₂SnO₄ and their point defects: A comparative study using first-principles methods — •Arno Fey, Péter Ágoston, and Karsten Albe — Institut für Materialwissenschaft, Technische Universität Darmstadt, Petersenstr. 32, 64287 Darmstadt

Ternary oxides represent a possible alternative to current transparent conducting oxides (TCOs). Although high electric conductivities were found for Cd₂SnO₄, the presence of toxic Cadmium in widespread devices is a massive drawback. A possible alternative is Zn₂SnO₄ which is non-toxic and chemically similar, but until now its conductivity is more than one order of magnitude lower. In this study we investigate both, Cd₂SnO₄ and Zn₂SnO₄, by quantum mechanical calculations within density functional theory (DFT) in order to elucidate the reasons for the different conductivities. We study the thermodynamic stability of various arrangements of the cations in the inverse spinel structure, and the intrinsic point defects as a source for the conductivity. Our results show that Cd₂SnO₄ is thermodynamically stable for certain cation distributions, while no stable phase for Zn₂SnO₄ can be identified. The Sn_Cd- and Sn_Zn-antisite are the source of the n-type conductivity in these materials.