The effect of using different types of window layer on the performance of thin-film solar cell based on CdTe
was studied. Here, we investigated Cadmium Sulphide (CdS), Zinc Selenide (ZnSe) and Zinc Sulphide (ZnS) as window
layer candidates. The calculations of short-circuit current density, internal quantum efficacy, external quantum efficient
and the solar cell efficacy were achieved based on the optical and recombination losses. The calculation of the optical
losses was performed considering the reflection process at the interfaces of the contacted layer and absorption process in
the frontal charge-collecting and window layers. The recombination loss estimates on both front and back surfaces of the
CdTe layer is based upon the physical parameters of the window/absorber junction and absorber layer. It was found that
the highest short-circuit current density of 26 mA/cm2, the lowest optical and recombination losses of 16% and
consequently the highest cell efficiency of about 21.3% were achieved for ZnS window layer. For CdS window layer, the
values of short-circuits current density, optical and recombination losses and cell efficiency were 23.38 mA/cm2, 25% and
19%, respectively. The corresponding values of ZnSe layer were between those of ZnS and CdS. These results show that
ZnS is considered a good alternative material for the traditional CdS window layer or at least it makes a promising alloy
with CdS.