Effects of sulfurization time and H2S concentration on electrical properties of Cu2ZnSnS4 films prepared by sol–gel method

Abstract

Cu2ZnSnS4 (CZTS) thin films have been successfully deposited by a sol–gel method and sulfurization process. The properties of the films were investigated by varying sulfurization time and H2S concentration. X-ray diffraction and Raman spectra analyses revealed the formation of CZTS films with a tetragonal type kesterite structure. With increasing the sulfurization time and H2S concentration, the intensity of the kesterite (112) peak became sharper. The stoichiometric ratios of the CZTS films were different from the precursors, which was due to Sn loss during the sulfurization process. The electrical resistivity and mobility of the films increased while the carrier concentration decreased with increasing the sulfurization time. The CZTS thin films sulfurized at 5% H2S concentration for 90min had the best opto-electrical properties with Eg of 1.41eV, resistivity of 3.64Ωcm, carrier concentration of 1.11×1018cm−3 and mobility of 1.54cm2/(Vs) at room temperature for PV application.