Pure CdS thin films with different condition have been successfully deposited by thermal evaporation in vacuum on glass slide substrates. The substrates temperature of about 100oC and the vacuum of about 10-6 torr. The film was annealing with different temperature (300 to 500oC) and different time of annealing (10 to 85min). The film structure properties were characterized by x-ray diffraction (XRD). XRD
patterns indicated the presence of single –phase hexagonal CdS with good crystalline, some of the structural characterization such as lattice constant, average grain size and micro strain are calculated from the X-rays pattern. The average roughness was obtained by using AFM scanning microscope, which shows that the average roughness decreased with increase the annealing temperature. Direct band gap
values of (2.35 to 2.15eV) for different annealing temperature (300-500oC) and (2.34 to 2.33eV) for (10min to 85min) annealing time at 200oC annealing temperature respectively, the transmission value of prepared samples are between (50-80%).