Reactive Sputtering Process for CuIn1-xGaxSe2 Thin Film Solar Cells

CuIn1-xGaxSe2 (CIGS) thin films are grown on Mo/soda lime glass using a reactive sputtering process in which a Se cracker is used to deliver reactive Se molecules. The Cu and (In0.7Ga0.3)(2)Se-3 targets are simultaneously sputtered under the delivery of reactive Se. The effects of Se flux on film composition are investigated The Cu/(In+Ga) composition ratio increases as the Se flux increases at a plasma power of less than 30 W for the Cu target. The (112) crystal orientation becomes dominant, and crystal grain size is larger with Se flux. The power conversion efficiency of a solar cell fabricated using an 800-nm CIGS film is 8.5%.