Dense Cu2ZnSnSe4 (CZTSe) thin films with large grains of 1-6 mu m were prepared by sputtering a metallic Cu-Zn-Sn target followed by a selenization process at 600 degrees C. Selenization of Cu-Zn-Sn metallic films with the aid of (SnSe2+Se) and CuSe2 was explained, which involved the nucleation and growth stages. The design of modified Cu(ln,Ga)Se-2 barrier layer prevented high-temperature reactions between the Mo electrode and as-deposited film and led to a pore-free interface. Using our simple approach, passivated and large grains were formed in an absorption layer, which is important for fabricating CZTSe solar cells. (C) 2013 Elsevier B.V. All rights reserved.