STUDYING THE EFFECT OF DEPOSITION CONDITIONS AND DOPING ON THE PROPERTIES OF ZnTe THIN FILMS

ZnTe films have been prepared by two-sourced thermal evaporation. The effects of the deposition parameters, such as evaporation rate and substrate temperature, on the optical, and structural properties as well as the resulting composition of the films were studied. The optical parameters of the films ( Le. refractive index, absorption coefficient, optical band gap and film thickness) were calculated from the normal transmittance data. A 'model was proposed for the calculation of the optical parameters from the transmittance spectra. The transmittance formula, derived for using in the proposed model, includes most of the parameters affecting the transmittance spectra, i.e finite substrate thickness. absorption of the substrate, thickness irregularity of the film surface, reflection from the back side of the substrate in addition to the refractive index and absorption of the film itself. The model was checked by theoretically simulated transmittance spectra as well as experimental data, and good accuracy was confirmed. Comparison of fitting of different transmittance formulas, as well as different models for the refractive index and the absorption coefficient also were done.\ud \ud For reducing the resistivity of ZnTe films. Doping with different materials were performed. Cu and Ag doping was done by an ion exchange process, which is by immersion of the ZnTe films into a copper nitrate solution (in case of Cu doping). The solution temperature was fixed, and the effect of the immersion time and post vacuum heat treatment, on the physical properties and the composition of the resulting films was studied.\ud \ud Three sourced evaporation from the elemental sources, was used for Sb doping. The resulting composition of the films was controlled by controlling the elements flux ratio as well as the substrate temperature. The structure of the films was studied by X-ray diffraction and the composition of the resulting films was measured by electron microprobe analysis (EMPA)