Assessment of the Impact of Annealing on the OpticalProperties of Cadmium Sulfide Thin Films by Spin CoatingDeposition (SCD)

Abstract

Cadmium sulfide (CdS) thin films have been fabricated on glass substrates via the spin-coating method,
followed by thermal annealing at 100°C, 150°C, and 200°C. Optical studies indicated that the deposited films
possess high transparency in the visible and near-infrared regions, with transmittance values reaching approximately
75%. The films exhibited a direct optical band gap, which showed a gradual decrease from 2.2 eV to 1.6 eV as the
annealing temperature increased. Additionally, increasing the annealing temperature resulted in noticeable
improvements in film homogeneity and crystallinity. These findings underscore the crucial role of thermal annealing
in modulating the optical properties of CdS thin films, thereby improving their suitability for optoelectronic
applications.