Optimization of windows in ZnO-CdS-CuInSe/sub 2/ heterojunctions

Major improvement of the performance of CuInSe/sub 2/-based heterojunctions has been obtained by replacing (Zn,Cd)S by a multilayer window consisting of ZnO and thin CdS buffer. The tradeoff between conductivity of the ZnO:Al and infrared free carrier absorption has been studied in connection with a n/sup +/n doping gradient. Bath chemistry of the CBD-CdS, (in particular different Cd-salts like CdCl/sub 2/, CdI/sub 2/, and CdSO/sub 4/) plays an important role in the resulting cell performances. XPS and UPS analyses have been carried out in order to investigate contaminations, coverage of the CuInSe/sub 2/ surface, and growth kinetics of the CdS layers grown in different baths. Optimized CdS thickness has been experimentally determined.<
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