Cu2ZnSnSe4 (CZTSe) thin films were deposited on Mo-coated soda-lime glass substrates by single-stage co-evaporation process and the effect of substrate temperature (T-sub) was investigated on the CZTSe thin film growth during the process. The film thickness decreased and the grain size increased with increasing T-sub. The optimum substrate temperature to obtain CZTSe films was found to be 593 K. The film grown at T-sub of 773 K seems to have the phase decomposition into CuxSe and ZnSe, probably because of Sn loss during the process. The best cell fabricated with a CZTSe absorber layer grown at T-sub of 593 K produced 2.88% of conversion efficiency. (C) 2012 Elsevier B.V. All rights reserved.