Dresden 2009 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.75: Poster

Thursday, March 26, 2009, 15:00–17:30, P2

Hard x-ray photoelectron spectroscopy of chalcopyrite based solar cells — •Christian D.R. Ludwig¹, Catherine A. Jenkins², Xuefang F. Dai³, Andrei Gloskovskii³, Gerhard H. Fecher³, Claudia Felser³, Benjamin Johnson⁴, Joachim Klaer⁴, Iver Lauermann⁴, and Raquel Caballero⁴ — ¹Institute for Physics, Johannes Gutenberg - University, 55099 Mainz — ²Department of Materials Science and Engineering, University of California, Berkeley, 94720, USA — ³Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, 55099 Mainz — ⁴Helmholtz-Zentrum für Materialien und Energie, 14109 Berlin

Chalcopyrite based solar modules combine advantages of thin-film technology with the high efficiency and stability of conventional crystalline silicon cells. Hard x-ray photoemission spectroscopy (HAXPES) allows the investigation of a total buffer/absorber/substrate device stack, due to a mean free path of the excited electrons of a few tens of unit cells. The chalcopyrite compounds Cu(In,Ga)Se₂ and CuInS₂ with a CdS capping were investigated at BESSY, Berlin and at SPring8, Japan. The excitation energy was varied from 2.2 keV to 8 keV. The experimental results are compared to first principle electronic structure calculations based on density functional theory. The densities of states of the valence bands of uncapped compounds agree well with photoemission spectroscopy data and it is shown that HAXPES is a technique capable of resolving the valence bands of interfaces, buried under a CdS capping. This work is funded by the Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (project 0327665A).