Current Photovoltaic Research ISSN:2288-3274(Print) 2508-125X(Online)

High efficiency Cu(In,Ga)Se2 solar cells are generally prepared above 500°C. Lowering the process temperature can allow wider selection of substrate material and process window. In this paper, the three-stage co-evaporation process widely used to grow CIGS thin film at high temperature was modified to reduce the maximum substrate temperature. Below 400°C the CIGS films show poor crystal growth and lower solar cell performance, in spite of external Na doping by NaF. As a new approach, Cu source instead of Cu with Se in the second stage was applied on the (In,Ga)2Se3 precursor at 400°C and achieved a better crystal growth. The distribution of Ga in the films produce by new method were investigated and solar cells were fabricated using these films.