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O: Fachverband Oberflächenphysik

O 68: Semiconductor substrates: Epitaxy and growth

O 68.8: Vortrag

Donnerstag, 25. März 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.

S.B. Zhang et al., Phys. Rev. B 57, 9642 (1998)
S.B. Zhang and S.-H. Wei, Phys. Rev. B 65, 081402 (2002)