We have synthesized an efficient Cu2ZnSn(SxSe1-x)(4) (CZTSSe) absorbers by using single-step rapid thermal sulfo-selenization process of sputtered stack metallic precursor (Zn/Sn/Cu) films. The structural and morphological studies confirm that the suitability of the rapid thermal sulfo-selenization process for the synthesis of a CZTSSe absorber without any secondary phases with large grains. The annealing atmosphere with a mixed-chalcogen source enhances the grain growth of the CZTSSe absorber as compared with pure Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) absorbers. The CZTSSe thin film solar cell shows the best conversion efficiency of similar to 7%. (C) 2014 Elsevier B. V. All rights reserved.