Electrical properties of ZnS films produced by spray pyrolysis method in the form of sandwich and planar structures

Polycrystalline ZnS semiconducting films have been prepared in planar and sandwich configurations by spray pyrolysis technique using amorphous and ZnO coated glass substrates. The produced ZnS films have been crystallized in a wurtzite structure and had a direct band gap energy of 3.62 eV. The electrical properties of the samples have been studied by an analysis based on currentvoltage characteristics and the thermally stimulated current measurements performed in the temperature range of 40?300 K with various heating rates. A set of curves of I (T) for varying initial density of filled traps at a heating rate of ß2=0.06 K s-1 indicate that the observed peaks in the TSC curve of ZnS films have first-order features. In order to evaluate the trap parameters of ZnS films, we have used the curve fitting method. The values of the frequency factor ? , the capture cross section S and the concentration of the traps Nt have been determined for three first-order peaks in the TSC spectrum of ZnS. Keywords: Thermally Stimulated Current, Trapping Parameters, Sandwich Structure, Zinc Sulphide, Spray Pyrolysis