Indium sulfide thin films deposited by chemical spray of aqueous and alcoholic solutions

Abstract

In2S3 films were grown by pneumatic chemical spray method using aqueous and alcoholic solutions containing InCl 3 and SC(NH2)2 at molar ratios of [In]/[S]=1/3 and 1/6. Films were deposited onto preheated glass sheets in air at heater (molten Sn bath) temperatures of 250 and 330 °C. Films were characterized by means of XRD, SEM, UV-VIS spectra and XPS. β- In2S3 films were formed independent of the technological variables. The films from aqueous solutions are highly orientated along (0 0 12) plane parallel to the substrate, with Eg of 2.2-2.3 eV (indirect transitions). Spray of alcoholic solutions results in thinner but more compact films with reduced (0 0 12) orientation, Eg of ca. 2.0 eV, and no chlorine contamination when deposited at 330 °C. According to XPS, the films have uniform concentration of the elements through the film thickness, spray of sulfur-rich solutions ([In]/[S]=1/6) results in the films with lower oxygen content.