Characterization and deposition of Cu2ZnSnS4 film for thin solar cells via sol-gel method

To achieve low-cost and high-efficiency of thin-film solar cells applications, the sol-gel method that can be coated on a large area substrate, obtain homogeneous thin films of high purity was used. We studied structural and optical characteristics versus annealing temperature of Cu2ZnSnS4 which has kesterite structure by substitution low-cost sulfur (S) instead of high-cost selenium (Se). By analyzing XRD patterns, main peak was observed at 2. = 28.5 o when Zn/ Sn ratio is 0.8/1.2. And when we observed kesterite structure which has orientation of (112) direction, the more annealing temperature increase the bigger strength of (112) direction is. Cu2ZnSnS4 thin film showed characteristics of kesterite structure at 550 degrees C. And when we calculated lattice constant, a = 5.5047 and c = 11.014 angstrom as same JCPDS (Joint Committee on Powder Standards) data measured. We measured optical transmittance to analyze optical characteristics. Optical transmittance was lower than 65 % at visible ray (lambda = 380 similar to 770 nm).