The document summarizes research on the optical and atomic force microscopy (AFM) studies of cadmium sulfide (CdS) thin films prepared by vacuum evaporation. CdS thin films of varying thicknesses were deposited on glass substrates. The optical band gap, absorption coefficient, and extinction coefficient were estimated from optical measurements. AFM images showed the surface morphology consists of round nano particles with grain sizes ranging from 40-180 nm. Both the optical band gap and particle size increased with increasing film thickness, while the extinction coefficient decreased with thickness.