Optimization of sulphurization temperature for the production of single-phase CZTS kesterite layers synthesized by electrodeposition

Abstract

Cu2ZnSnS4 films were grown onto FTO/glass substrate by electrodeposition. The influence of sulphurization temperature on CZTS properties was examined using XRD, Raman spectroscopy, SEM, optical transmittance and electrical resistivity measurements. The film sulphurized at 400°C exhibited CuS as the major phase mixed with CZTS and SnS2 phases. However, the films sulphurized at 450 and 500°C are mainly composed of the CZTS kesterite phase with SnS2 and CuS as secondary phases. Further sulphurization temperature increase up to 550°C led to the complete disappearance of CuS and SnS2 phases and the obtained film is a pure CZTS kesterite mono-phase. The Raman spectra exhibit a line centred at 334 cm−1; it is the most intense recorded in the spectra of the films sulphurized at 500 and 550°C. The film sulphurized at 550 °C, had an ideal band gap of 1.40 eV and electrical resistivity of (41.4 ± 5.5) Ω cm.