Simulation of Effects of Defects and Layers Thickness on the Performance of CIGS Solar Cells

A CIGS based solar cell structure with new proposed thicknesses of different layers has been carried out using Atlas module from SILVACO technology computer-aided design (T-CAD). The purpose of this paper is to enhance the efficiency by varying the thickness of each layer and optimizing the anti-reflective coating layer, as well. The optimization takes into account the defects in different layers and at interfaces. Our contribution focuses on reducing the layers' thicknesses and maintains the efficiency as high as possible with respect to experimental results. Short-circuit current density J(SC), open-circuit voltage V-OC, fill factor FF, and conversion efficiency eta were calculated and compared in each case in order to find out the best structure. The results showed that the optimal thicknesses of 0.11, 0.25, 0.03, and 1.6 mu m for ARC layer, ZnO window layer, CdS buffer layer, and GIGS absorbent layer, respectively, give a conversion efficiency of 20.64%, which is close to experimental one.