Abstract
The main focus of this study was on the invention of device quality CIAS absorber layer with bigger grain size and smooth surface for CIAS solar cell. Initially we optimized the selenization process parameters such as temperature and time duration to produce CIAS absorber layer, but CIAS solar cell fabricated with this CIAS layer showed low efficiency and this is due to the rough surface and porous structure of CIAS absorber layer which causes serious leakage current. We carried out experiments to study the factors influencing CIAS absorber layer quality. The characteristics of Mo back contact layer including the interface between CIAS absorber layer and Mo layer and also the Na diffusion from SLG to CIAS absorber layer are influencing the CIAS absorber layer quality to a great extent. In spite of these factors, the amount of Se powder used for selenization process to produce CIAS layer from CIA precursor also influenced the quality of CIAS absorber layer through the formation of MoSe2 at the interface between these two layers. It was noticed that the MoSe2 formed at the interface could help the CIAS layer grow with smooth surface along the MoSe2 (100) hexagonal lattice direction. As we know that Na diffusion from SLG could help to obtain bigger CIAS grain formation, density and thickness of Mo was adjusted to control Na diffusion and finally, we achieved good quality CIAS absorber film to fabricate CIAS cell. The best cell CIAS cell fabricated showed an efficiency of 2.256% with a VOC of 0.24 V, JSC of 25.364 mA/cm2, and the F.F. of 0.371.