Studying the effect of annealing temperatures on the optical properties of CdS:1% Cu nanoparticles thin films prepared by thermal evaporation technique

In the present study, thermal evaporation technique in vacuum has been use to prepare CdS thin films doped with 1% Cu nanoparticles with average particles sizes 50 nm. The effect of annealing temperatures with different ranges (R.T, 250, 300 and 350) degrees C on the structural and the optical properties of the prepared thins films were studied. The XRD technique has been use to study the structural properties of the prepared thins films. The AFM analysis shows that the increase in the (RMS) leads to decrease in the roughness values by increasing of the annealing temperature. The optical measurements showed that the CdS: 1% Cu films have direct optical energies gaps (E-g), and it decreases from 2.43 eV to 2.39 eV with the increasing of annealing temperatures (R.T - 350) degrees C. The optical properties had measured in the range (200-800) nm of wavelength. The refractive index (n), extinction coefficient (k), absorption coefficient (alpha) and the real and imaginary dielectrics constants (epsilon(r) and epsilon(i)) increased by increasing the annealing temperature.