Effect Annealing Temperature on the Physical Properties of Cadmium Sulphide thin Films Deposited by using Thermal Evaporation Technique

Abstract

This study measured some of the structural, electrical and optical properties of cadmium sulfide (CdS) thin films with thickness of 150 nm deposited on glass substrate by using thermal evaporation system under vacuum pressure 1x10−5mbar. X-ray diffraction technology was used to analyses the structural properties of the CdS films. Results showed that the CdS films type cube polycrystalline structure and the preferred growth path was [111].In evaluating DC conductivity, we observed two mechanism of activation energy. In the measuring Hall effect shows that the electrical conductivity of the CdS films is negative carriers (n-type). The result of the (AFM) measurements showed that the grain size and average roughness increased with annealing temperature increased. In optical properties it were found that transmittance 80% at RT that decreases with increasing annealing temperature. It also found that absorption coefficient, extinction coefficient and refraction index increased with increasing annealing temperature. Optical energy gap were found decreased with increasing annealing temperature as (RT, 150 and 300 C°) the results (2.4, 2.38 and 2.32 eV) respectively. The results electrical properties showed that the CdS thin films had two activation energy and Hall effect were found that the mobility increase with increasing annealing temperature.