The selenization mechanism of Sn and Zn thin films was investigated by in situ high-temperature X-ray diffraction analysis of glass/Mo/Sn(/Se) and glass/Mo/Zn(/Se) precursors. The Sn and Zn layers were deposited by sputtering, and amorphous Se layer was added by evaporation. Based on the results of isothermal reactions at different set temperatures, the kinetic parameters for the transformation of the SnSe2 to SnSe phases and the selenization of Zn to ZnSe were estimated. It was found that severe Sn loss also occurred during the selenization of glass/Mo/Sn/Se precursor, while Zn loss was relatively negligible during the selenization of glass/Mo/Zn/Se precursor. (C) 2013 Elsevier B.V. All rights reserved.