Influence of CdS window layer on 2-μm thick CdS/CdTe thin film solar cells

Influence of the CdS window layer on the PV performances of 2-μm thick CdS/CdTe solar cells has been studied as a function of the CdS thickness, dCdS. With a reduction of dCdS from 114 to 95 nm, JSC increases due to an increase in blue response. While, at dCdS<85 nm, the conversion efficiency largely decreases due to a decrease in VOC and FF. The deterioration of the crystallinity of CdTe due to a decrease in the sulfur composition x of the CdTe1−xSx mixed-crystal layer is concluded to be the most possible mechanism for the large decreases in VOC and FF.