Fabrication of CuIn1−xGaxSe2 thin film solar cells by sputtering and selenization process

Abstract CuIn1−xGaxSe2 polycrystalline thin films were prepared by the two-step method. Cu–In–Ga metallic precursors were deposited sequentially or simultaneously using both Cu–Ga (23 at.%) alloy and In targets by DC magnetron sputtering. The metallic precursor films were selenized in vacuum evaporation system. It is found that the CuIn1−xGaxSe2 chalcopyrite phase was formed from In–Se compounds (InSe and In2Se3) and Cu3Ga during the early stage of selenization. The flattening of CuIn1−xGaxSe2 film seemed to be achieved by the formation of liquid In–Se compound phase during the selenization. The fabricated CuIn1−xGaxSe2 films showed a smooth surface morphology and contained a single chalcopyrite phase.