Effect of H2S treatment on properties of CuInS2 thin films deposited by chemical spray pyrolysis at low temperature

CuInS2 thin films were deposited by chemical spray of aqueous solutions containing CuCl2, InCl3 and thiourea at substrate temperature of 250°C in air and subjected to annealing at 530°C in H2S atmosphere. Structure and composition before and after annealing were studied by XRD, EDS, XPS and Raman spectroscopy. As-sprayed films were low-crystalline, showed uniform distribution of elements in film thickness and no oxygen content. For the CuInS2 films deposited from the solutions with [Cu2+]/[In3+]=1.0 and 1.1, H2S treatment for 30min increased the chalcopyrite content up to 73% and 51%, respectively. CuXS phase in sprayed CIS films promotes the crystallite growth but retards the formation of chalcopyrite phase during H2S treatment.