Electrical properties of CuxZnySnS4 films with different Cu/Zn ratios

p-Type conduction in Cu2ZnSnS4 (CZTS) thin films was realized by the sol-gel method. Measurements of electrical properties with the changes in the Cu/Zn ratio were carried out to determine defect behaviors. Combining with Hall, Raman, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction results, a direct link between the CuZn antisite, conduction type and hole concentration of CZTS films was established. Types of conduction and carrier density in CZTS films were found to be dependent on the Cu/Zn ratio. The formation of p-type conductivity in CZTS films might be due to the increased CuZn density.