Deposition of pristine and Ho-doped nanocrystalline CdS thin films and their characterization for solar application.

By using a modified chemical bath deposition method, pristine and Ho mixed cadmium sulfied thin films were fabricated on an adequately cleaned substrate. For the fabrication of films, an hour-long water bath deposition process at 80°C was used. When Ho is doped into CdS, the thickness of the films varies. Utilizing UV-Visible spectroscopy and XRD the characteristics of the fabricated films were examined. Structural analysis provides confirmation of the formation of the cubic structure. By using XRD, the other lattice parameters of the deposited pristine and Ho doped CdS thin films such as crystallite size, lattice constant, inter planar distance, strain, and density of dislocation were also investigated. Pure CdS thin films are found to have crystallite sizes of 2 nm, which increased to 24 nm with Ho doping. With increase in Ho doping concentration, the micro strain and dislocation density of the films were reduced. The blue shift that occurred in the absorption edge of films provided evidence of quantum confinement. The band gap y of the prepared sample was estimated to be between 2.4 and 2.55 eV. [ABSTRACT FROM AUTHOR]