Highlighting some layers properties in performances optimization of CIGSe based solar cells: Case of Cu(In, Ga)Se–ZnS

Abstract

In this research work which is based on recent studies, we investigated the effects of the physical properties of the Zinc Sulfide (ZnS) buffer layer such as electronic affinity, doping concentration and thickness on the electrical parameters of a defined solar cell structure. These properties values, combined with those of the CIGSe absorber layer and other materials that make up our cell, provide vital information on the optimization of the layer properties that enhance the efficiency of the CIGSe based ultra-thin solar cells. After a judicious choice of the input parameters of the materials constituting our solar cell device, we obtained employing SCAPS numerical simulation software, electrical parameters more interesting than those found in the literature. In particular, for 5 nm thickness of the ZnS buffer layer and 500 nm thickness of the CuIn0.7Ga0.3Se2 absorber layer, we obtained an efficiency η = 21.42% and a fill factor FF = 82.16%. For 5 nm thickness of the ZnS buffer layer and 2500 nm thickness of the CuIn0.7Ga0.3Se2 absorber layer, we obtain an efficiency η = 26.30% and a fill factor FF = 85.15% with a good choice of others material properties such as intrinsic doping concentration, electrons and holes mobility. A good knowledge of the exact parameters of simulations, allowed us to determine the values of the optimal properties of the Cu(In, Ga)Se–ZnS solar cell, useful for their physical implementation.