Back contact selenization and absorber layer etching for improvement in Schottky diode behavior of [Mo/CIGS/Al] structure

Abstract

The effect of back contact selenization and absorber layer etching on Cu(In,Ga)Se2 (CIGS) structure for thin-film solar cell applications was investigated. Considering the dependence of the efficiency of solar cells on the performance of the absorber layer, it is essential to find its optimum parameters. This study deals with the influence of selenization of Mo layer and KCN chemical etching of the absorber layer on the structure. The Schottky diode current-voltage curves of [Glass/Mo/CIGS] samples with the selenized Mo layer showed enhanced current intensity which was confirmed by the presence of MoSe2 phase in XRD patterns. The wet KCN etching was used to remove the copper sulfide impurities, thereby higher shunt resistance was achieved in the etched samples. The effectiveness of etching treatment was confirmed by SEM images and EDX analysis. Our results showed that the selenization of the Mo layer and etching of the absorber layer lead to a decrease in the series resistance and an increase in the sheet and shunt resistances. Moreover, the rectifying factor was enhanced about 150% with an ideality factor of 2.87.