Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 32: Photovoltaic

HL 32.4: Talk

Wednesday, March 29, 2006, 15:15–15:30, BEY 118

Influence of grain boundaries on electric transport in chalcopyrites — •Mark Wimmer, Susanne Siebentritt, Thorsten Rissom, Tobias Eisenbarth, and Martha Lux-Steiner — Hahn-Meitner-Institut, Glienicker Str. 100, 14109 Berlin

The chalcopyrite Cu(In,Ga) Se₂ is successfully used as an absorber in photovoltaic devices. The chalcopyrite photoactive layers have, among others, the advantage of being useful in the polycrystalline form. Although grain boundaries, as the essential difference between single- and polycrystalline materials, may play an important role for the performance of the devices there is currently no commonly accepted model for the electronic structure of the grain boundaries. To analyze the specific influence of grain boundaries on the carrier transport we grew CuGaSe₂-bicrystals by metal organic vapour phase epitaxy and studied them by Hall-measurements. Hall-Measurements allow to identify the barrier height for the majority carriers which is found to be at about 100meV in polycrystalline materials. The bicrystals allow the investigations of single grain boundaries. The behaviour of the bicrystals under illumination will be discussed as well as the behaviour of annealed samples.