LAUSR

Abstract Preparing CIGS thin films with grain size above 1 μm based on quaternary CIGS target is difficult, which is a barrier for the further enhancement of CIGS cell efficiency. We proposed a two-stage method to overcome this problem. Cu-rich CIGS thin film was prepared from quaternary CIGS and Cu target and then converted into Cu-poor CIGS by depositing the In 2 Se 3 layer on the Cu-rich CIGS with the subsequent annealing. CIGS absorbers with micrometer-sized crystal based on quaternary CIGS target was prepared. The influence of the In 2 Se 3 deposition on the physical properties of the CIGS absorber and CIGS cells has been investigated. The thickness of In 2 Se 3 layer has been optimized which can result in the highest conversion efficiency of 9.5% in Cu-rich CIGS based solar cells.