Structural, electrical and optical properties of Bi-doped CuInS2 thin films prepared by a single-source thermal evaporation method were investigated. The as-deposited films were annealed in the temperature range between 100 and 500 °C for 10 min in air. The film of chalcopyrite CuInS2 single phase was obtained by annealing at 200 °C successfully. It was found that Bi atoms enhanced the growth of CuInS2 single phase at lower temperature. Furthermore, the crystalline quality of doped films was higher compared with the non-doped ones. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)