Some physical investigations on AgInS2 sprayed thin films

Abstract

AgInS2 thin films have been prepared on glass substrates by the spray pyrolysis process using an aqueous solution which contains silver acetate (AgCH3CO2), thiourea (SC(NH2)2) and indium chloride (InCl3) as precursors. The depositions were carried out in the range of the substrate temperature from 260 to 420 °C. The value of the concentration ratio in the spray solution of indium and silver elements x=[Ag+]/[In3+] was varied from 1 to 1.5 with [In3+]=10−2 M and [S2−]/[In3+] was taken constant, equal to 4. The structural study shows that AgInS2 thin film, prepared at 420 °C using optimal concentration ratio x=1.3 crystallizes in the chalcopyrite phase with a strong (1 1 2) X-ray diffraction line. Moreover, microprobe analysis (EPMA) shows that a nearly stoichiometric composition is obtained for these experimental conditions. Indeed, the atomic percentage of elements were. 24.5, 25.0, 49.5 for Ag, In and S, respectively. On the other hand from transmission and reflectance spectra, the obtained band gap energy is 1.83 eV for such film.