Structural and optical properties of Cu$_{2}$ZnSn(S,Se)$_{4}$ films obtained by magnetron sputtering of a Cu$_{2}$ZnSn alloy target

Results of the study of structural and optical properties of Cu$_{2}$ZnSn(S,Se)$_{4}$ thin films obtained by sulfitation (selenization) of Cu$_{2}$ZnSn films which were sputtered by target direct current magnetron sputtering using a stoichiometric Cu$_{2}$ZnSn (99.99%) target are presented. It has been found that Cu$_{2}$ZnSn(S,Se)$_{4}$ thin films are polycrystalline with a grain size of $\sim$60 nm. The optical bandgap of Cu$_{2}$ZnSnS$_{4}$ ($E^{op}_{g}$ = 1.65 eV) and Cu$_{2}$ZnSnSe$_{4}$ ($R^{op}_{g}$ = 1.2 eV) thin films have been determined.