Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 32: Photovoltaic

HL 32.6: Talk

Wednesday, March 29, 2006, 15:45–16:00, BEY 118

Influence of grain boundaries on electrical and structural properties of chalcopyrites — •Tobias Eisenbarth, Susanne Siebentritt, Sascha Sadewasser, Jürgen Albert, Ferdinand Streicher, and Martha Lux-Steiner — Hahn-Meitner-Institut, Glienicker Str.100, 14109 Berlin

Thin film solar cells made from chalcopyrites (e.g. CuGaSe₂) are based on polycrystalline absorber layers with grains of different orientation. The influence of grain boundaries on recombination and electrical transport is not yet completely understood. But it can be assumed, that grain boundaries have a significant effect on the efficiency. Different models are discussed for the electronic structure of grain boundaries. In the present work, we grow epitaxial (MOVPE= Metal Organic Vapour Phase Epitaxy) CuGaSe₂ on a bicrystal GaAs-wafer with a single grain boundary. Depending on the Cu-content of the epitaxial film the epitaxy leads to two separate crystals or to a genuine grain boundary with defined orientation. This allows the detailed analysis a single grain boundary. We present results of scanning tunnelling microscopy, giving information about the crystalline and electronic structure of the grain boundary.