Effect of indium tin oxide substrate roughness on the morphology, structural and optical properties of CdS thin films

Indium tin oxide ITO.coatings of glass substrates were etched with hydrochloric acid in order to obtain different root-mean-square roughness RITO.on its surface. The effect of RITO on the morphology, structural and optical properties of CdS films deposited was investigated. Polycrystalline cadmium sulfide thin films were deposited on ITOrglass substrates by chemical-bath deposition CBD.at 358 K, and studied by atomic force microscopy AFM.. Roughness of CdS films RCdS. showed a nearly linear increase with RITO. The thickness of CdS films was investigated by Auger Electron Spectroscopy AES.and showed an increment with RCdS. X-ray diffraction results showed that CdS films have a cubic zincblende structure with a 111.preferred orientation. The measured residual strain of the CdS films showed an initial increse with RITO reaching a maximum point at 15"2 nm, and after that exhibited a decreasing dependence. The optical band gap Eo of the CdS films obtained from transmittance measurements did not depend on RITO. q2000 Elsevier Science B.V. All rights reserved.