Structural electrical and optical properties of Zn rich CZTS thin film

Cu₂ZnSnS₄ (CZTS) thin films have been deposited by co-sputtering technique from a CZTS and ZnS target on top of glass substrate aiming to increase the Zn content on the CZTS thin films. The prepared sample was annealed at 500 °C in a high vacuum (50mTorr) ambient for 20 min. of duration. Structural, compositional, and electrical properties of the prepared films were carried out in this study. The change in the microstructure with subsequent recrystallization and grain growth was observed in annealed thin film. The peak intensity as well as crystallite grain size was observed to increase by the effect of annealing, whereas the dislocation densities and microstrain of the films are reduced as observed in XRD analysis. The films are found in Zn rich kesterite structure with a good stoichiometry. The annealing process increases the film resistivity from 17.78 Ω-cm to 192.60 Ω-cm corresponding to the as-deposited and annealed CZTS thin films. The bandgap of the films are observed to decrease by the effect of annealing process.