IMPROVED PERFORMANCE OF CU(INGA)SE2 THIN-FILM SOLAR-CELLS USING EVAPORATED CD-FREE BUFFER LAYERS

Polycrystalline Cu(InGa)Se-2 (CIGS) thin-film solar cells using evapor ated InxSey and ZnInxSey buffer layers are prepared. The purpose of th is work is to replace the chemical bath deposited CdS buffer layer wit h a continuously evaporated buffer layer. In this study, a major effor t is made to improve the performance of CIGS thin-film solar cells wit h these buffer layers. The relationship between the cell performance a nd the substrate temperature for these buffer layers is demonstrated. Even at the high substrate temperature of about 550 degrees C for the buffer layer, efficiencies of more than 11% were obtained. Furthermore , the I-V characteristics of the cells using these buffer layers are c ompared with cells using CdS buffer layers fabricated by chemical bath deposition method. We have achieved relatively high efficiencies of o ver 15% using both the ZnInxSey and the CdS buffer layers.