Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 68: Semiconductor substrates: Epitaxy and growth
O 68.8: Talk
Thursday, March 25, 2010, 12:15–12:30, H42
Surface electronic structure and morphology of epitaxial CuInSe2 — •Andreas Hofmann — Helmholtz-Zentrum Berlin für Materialien und Energie, Institut für Ladungsträgerdynamik (E-I4)
Solar cells based on chalcopyrite absorbers reach the highest efficiencies of all thin-film devices. However, the best laboratory cells still lag dramatically behind the theoretical energy conversion limit. So far, calculations for the surface reconstructions and electronic properties exist [1,2], but experimental data on crystalline material is sparse. Therefore, our approach is to study epitaxial CuInSe2 films as a model system with surface analytic techniques.
Samples of different orientation and stoichiometry were prepared by molecular beam epitaxy, the analysis was performed in-situ in a dedicated UHV system. LEED measurements confirmed the c(4x2) surface for near-stoichiometric CuInSe2(112) which was also predicted by calculation [1]. For the copper-depleted surface, however, a (1x1) structure is found. Angle-resolved photoemission data obtained for the (001) surface showed a good agreement with the band structure from DFT [2]. The morphology of surface with different orientation was investigated with scanning tunnelling microscopy.
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