Influence of Heat Treatment on the Structural and Electrical Properties of ZnS Thin Films


Zinc Sulfide thin films have been deposited onto glass substrates by spray pyrolysis method, the films were analyzed by X-ray diffraction and Hall Effect measurments.XRD analysis of the deposited and annealed films showed that all the films have polycrystalline with hexagonal structure. The effect of heat treatment enhances the grain size and improves the crystalline of the films, the grain size is found to increased from (18-40)nm, also the dislocation density (δ)decreased and in the range (1.6×1012 -1.01×1012)lines/cm. Electrical resistivity is changed after the films were exposed to heat treatment, the value of resistivity was decreased about (3) times than that before annealing. Moreover the activation energy was decreased (1.5-1.1)eV by heat treatment .Hall measurements proved that ZnS thin film is an n-type semiconductor with electron mobility around 160±10cm2/v.s. These results confirmed the improvement in crystallinity of the films with heat treatment at (400,500) °C because of decreasing crystal defects.