Synthesis and DFT calculations on electronic properties of ZnO-Sb thin film

Full text: In this work antimony (Sb) doped zinc oxide (ZnO) thin films were deposited on glass substrate at 400◦C using spray pyrolysis technique. To obtain the films, Sb₂O₃ was dissolved into a 0,2 M solution of zinc acetate and ethyl alcohol yielding mixtures of 3% up to 10% Sb₂O₃ molar fraction. The deposition was performed at controlled rate under nitrogen atmosphere. XRD measurements indicates polycrystalline morphology with hexagonal-wurtzite structure and Sb doping atoms incorporated in the ZnO structure. The optical characterization was performed using transmittance and specular reflection at normal incidence in Uv-Vis and NIR region. A quantum mechanical approach based on the periodic Density Functional Theory (DFT), with B3LYP hybrid potential was used to investigate the electronic structure of both ZnO and Sb substituted ZnO, aiming to contribute to a better understanding of the material behavior related with structure and optical properties. The CRYSTAL09 code has been used for the calculations. The calculations have been performed on the wurtzite hexagonal structure of ZnO - spatial group P63mc. The calculated structural and band structure parameters are in quite good agreement with the experimental measurements. This suggested that the semiconducting properties of ZnO arises from the overlapping of the 4s orbital of the conducting band of Zn and the 2p orbital of the top of valence band of O. Comparisons of the band structure and density of states, as project on the atoms as well on the orbitals, clearly informs on the changes in the ZnO properties through substitution of Zn atoms for Sb. (author)