Layer transfer of Cu(In,Ga)Se2 thin-film to alternative substrate and application to solar cells

To widen the variety of substrate choice of Cu(In,Ga)Se2 (CIGS) solar cells, a lift off process was developed without an intentional sacrifice layer between CIGS and Mo back contact layers. CIGS films grown on Mo/glass substrates were transferred to alternative substrates of glass and polyimide. Based on the transferred CIGS films, deices with ITO/ZnO/CdS/CIGS/Mo/epoxy/alternative-substrates structure were fabricated. Both solar cells showed almost half values of efficiencies compared to a CIGS solar cell fabricated with a standard process. Modifications on a back contact property and a composition profile of the CIGS layer will improve the device performance of the lift-off cells.