Synthesis and characterization of pure and Sb/Sn doped ZnTe for solar cell application

Solar cells are low-cost, highly efficient medium for the realization of a renewable and eco friendly energy source. Thin film of ZnTe and Sb/Sn doped ZnTe have been deposited on glass substrate by making use of evaporation technique at high vacuum. The influence on properties (structural, morphological and optical) due to Sb and Sn doping, were investigated. From XRD measurement it has been observed that nature of the film changes from polycrystalline to amorphous after addition of Sb/Sn dopants in ZnTe thin film. The composition and micro structural characterization were done by means of SEM and EDAX. For optical characterization of the samples, absorption spectra have been determined. The optical constants such as absorption coefficient (alpha), band gap and extinction coefficient (k) have been investigated in spectral range of 400-1000 nm. The change in the optical behavior of Sb/Sn doped ZnTe thin films is explained in terms of defect states.