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

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 degrees C exhibited CuS as the major phase mixed with CZTS and SnS2 phases. However, the films sulphurized at 450 and 500 degrees C are mainly composed of the CZTS kesterite phase with SnS2 and CuS as secondary phases. Further sulphurization temperature increase up to 550 degrees 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 degrees C. The film sulphurized at 550 degrees C, had an ideal band gap of 1.40 eV and electrical resistivity of (41.4 +/- 5.5) omega cm.