Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 35: New Materials: Optoelectronic and Photovoltaic Applications

HL 35.3: Vortrag

Mittwoch, 24. März 2010, 10:00–10:15, H13

Systematic ab initio study of half-Heusler materials for optoelectronic applications — Thomas Gruhn and •Claudia Felser — Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University, 55099 Mainz

The development of new, optimized optoelectronic devices depends crucially on the availability of semiconductors with taylored electronic and structural properties. At the moment, the majority of applications is based on a rather small set of semiconducting materials, while many more semiconductors exist in the huge class of ternary compounds. Especially, the class of 8-electron half-Heusler materials comprises a large number semiconducters with various properties.

With the help of ab initio density functional theory we have studied essentially all 8-electron half-Heusler compounds that are of technological relevance. For more than 650 compounds we have determined the optimum configuration by varying the lattice constant and permuting the elements over the sublattices. Within this exceptionally large data set we have studied the band structure and the lattice constants as a function of the electronegativities of the elements, the arrangement of the atoms, and the atomic radii. The results are used to select suitable materials for the buffer layer in thin-film solar cells with a Cu(In,Ga)Se₂ (CIGS) absorber layer. Considering the bandgap and the geometrical matching with the CIGS film, we have obtained a set of 29 compounds that are promissing materials for cadmium-free CIGS buffer layer. The authors gratefully acknowledge financial support by the DfG (Research Unit 559).