Reactive sputtering process for CuIn 1-xGaxSe 2 thin film solar cells

Abstract

CuIn 1-xGaxSe 2 (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 (In 0.7Ga 0.3) 2Se 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%. © 2012 ETRI.