Impact of substrate temperature on structural, morphological and optical properties of In2S3 thin films deposited on ITO/glass substrate by spray pyrolysis technique

In2S3 thin films were grown on indium tin oxide-coated glass substrates by a chemical spray pyrolysis technique at different substrate temperatures (300 degrees C, 360 degrees C, 400 degrees C and 460 degrees C). Structural analysis of the deposited films shows a combination of tetragonal and cubic structures. The crystallite size of the films increases with the substrate temperature. Elemental analysis reveals that the films deposited at substrate temperature of 360 degrees C are sulfur deficient. Surface topography of the In2S3 thin films was examined by atomic force microscopy (AFM), scanning electron microscopy (SEM) and optical profilometry. The results clearly show that the films adhere well to the substrate with good homogeneity. The surface roughness is also showed to increase with the substrate temperature. The optical properties of In2S3 thin films were studied as a function of wavelength. The transmittance spectra show that the film deposited at 300 degrees C acquires relatively high transmittance in the visible region. The optical band gap is found to be direct, and it decreases with the increase in substrate temperature. Photoluminescence (PL) study reveals blue and green emissions.