Deposition and characterization of Cu2ZnSnS4 thin films for photovoltaic applications

Cu2ZnSnS4 thin films were successfully deposited on glass substrates by a chemical bath deposition method for as-deposited and annealed films with different temperatures in sulphur atmosphere at 250 and 350 °C. The changes in structural and the optical phenomenon of as -deposited and annealed films have been studied. The powder X-ray diffraction (XRD) spectra show the tetragonal crystal structure of Cu2ZnSnS4(CZTS) thin films. The average crystallite size varies from 19.437 to 17.937 and 10.41 nm respectively, when the film was as-deposited and annealed at 250 and 350 °C. The surface morphologies of the as-grown surface show some voids with agglomerated particles. After sulphurization at 250 and 350 °C, the morphologies of the samples become dense. The band gap is estimated to be about 1.11 eV for the as-deposited film and 1.42 and 1.5 eV for the annealed films.