Growth and characterization of coevaporated Cu2SnSe3 thin films for photovoltaic applications

Cu2SnSe3 (CTSe) thin films were deposited at various growth temperatures (325-425 °C) by coevaporation on soda-lime glass substrates without postannealing. X-ray diffraction and Raman analysis revealed that a single-phase CTSe thin film with a cubic structure was obtained at a growth temperature of 400 °C. The direct optical band gap of the films grown at different growth temperatures was found to vary from 0.84 to 2.1 eV. The optical absorption coefficient of the films was above ~ 104 cm− 1. All CTSe thin films showed p-type conductivity with carrier concentrations of 1017-1021 cm− 3. Hole mobilities were found to range between 6.3 and 14 cm2V− 1 s− 1. Electrical properties changed significantly as a function of Cu/Sn ratio and growth temperature.