Effect of Ag doping on the optical and structural properties of CdS/polyvinyl alcohol thin films by thermolysis process

Abstract Cadmium sulfide (CdS) and silver (Ag) doped CdS thin films embedded in polyvinyl alcohol (PVA) have been prepared by using solvent casting method followed by thermolysis technique to study their optical and structural properties. The X-ray diffractogram of CdS/PVA thin films for undoped and doped with different concentration (1–5% by volume/volume ratio) of silver nitrate indicate polycrystallinity with mixed cubic and hexagonal phases. The films tend more towards hexagonal phase with increase in the concentration of Ag doping. The lattice strain calculated from Williamson-Hall plot increases with increase in Ag doping concentration. The crystallites size also increases with increase of Ag doping concentration. The synthesised films are nearly uniform. However, some agglomerated nanoparticles with nearly spherical in shape appears on the surface of the films. The photoluminescence spectroscopic analysis has shown the presence of defect states related to sulfur vacancies or cadmium interstitials. The film thicknesses have been estimated from the cross sectional micrographs, obtained by using scanning electron microscope.