In this study, the authors investigated the performance of different buffer layers through the electrical parameters such as Jsc, Voc, QE and η of the quaternary system Cu(In,Ga)Se2 solar cells. The performance of Cu(In,Ga)Se2
solar cells has been modeled and numerically simulated by using the SCAPS-1D device simulation tool. The cells with a ZnSe, Zn(O,S) and (Zn,Mg)O buffer layers were compared with the reference CdS buffer layer. The investigation of ZnSe, Zn(O, S) and (Zn,Mg)O-based cells to substitute the traditional CdS in the future shows that the ZnSe-buffer layer is a potential material to replace CdS, which revealed the best efficiency of 20.76%, the other electrical parameters are: JSC = 34.6 mA/cm2 VOC = 0.76 V and FF = 79.6%. The losses as a function of the temperature are estimated at 0.1%/K, among all kinds of buffer layers studied. We have also shown that the use of a high
band-gap buffer layer is necessary to obtain a better short-circuit current density JSC. From our results, we note that the chalcogenide solar cells with Zn-based alternative buffer layer have almost the same stability that the traditional CdS buffer layer solar cells have.

Thin Film Solar Cells, CIGS Absorber, Alternative Buffer Layers, SCAPS-1D, Electrical Parameters