Deposition and characterization of Cu_2ZnSnS_4 thin films for photovoltaic applications

摘要

Cu_2ZnSnS_4 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 ℃. 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 Cu_2ZnSnS_4(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 ℃. The surface morphologies of the as-grown surface show some voids with agglomerated particles. After sulphurization at 250 and 350 ℃, 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.