Potential fluctuations in compensated chalcopyrites

Cu-poor chalcopyrites are highly compensated and their band structure is dominated by fluctuating potentials. Since solar cell absorbers are made from these materials, a quantitative analysis of the amplitude of the fluctuations is needed. Photoluminescence measurements of CuInSe2 and CuGaSe2 with varying Cu deficiency offer a tool to access the fluctuations amplitude. The amplitude is found in both cases to increase with increasing Cu deficiency. There appears a trend for lower fluctuation amplitudes in CuInSe2 than CuGaSe2, at least for material close to stoichiometry. (c) 2006 Elsevier B.V. All rights reserved.