Effects of the growth temperature on the properties of spray deposited CuInS2 thin films for photovoltaic applications

CuInS2 absorber thin films were prepared by spray pyrolysis deposition at different substrate temperatures (250 degrees C, 300 degrees C and 350 degrees C) using an aqueous solution of CuCl2, InCl3 and SC(NH2)2 at a precursor molar ratio of Cu:In:S=1:1.25:4.5. The effect of the substrate's temperature on the structural, morphological, optical and electrical properties of CuInS2 thin films was investigated. The X-ray diffraction patterns showed that CuInS2 has a tetragonal structure. The results show that the films deposited at 300 degrees C have improved electrical conduction and photocurrent values. When increasing the substrate's temperature the absorbance decreases while the band gap energy increases, as a combined effect of crystallinity, morphology and deviation from stoichiometry. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.