Optimum Substrate Temperature in One-stage Co-evaporation of Cu(In,Ga)Se2 Thin Films for High-efficiency Solar Cells

One-stage co-evaporation of Cu(In,Ga)Se_2) thin film has strong potential for wide adoption in industry because of its simplicity compared with multiple-stage processes. This study investigated the effects of substrate temperature during CIGS film growth on the efficiency of the resulting ITO/ZnO/CdS/CIGS/Mo structures. CIGS thin films were grown by one-stage co-evaporation at substrate temperatures ranging from 525 to 550 ℃. It was found that the device with CIGS film grown at 535 ℃ achieved the highest cell efficiency. In XRD patterns, films grown at this substrate temperature had the largest texture coefficient for the (220) plane and the smallest full widths at half maximum for both the (112) and (220) planes. Other cell electrical characteristics were also largest for this substrate temperature. Thus, we conclude that the optimal morphological characteristics of CIGS thin films grown at 535 ℃ are responsible for the high efficiency. KCI Citation Count: 5