Ab initio studies of the Sn-doped ZnO transparent conductive oxide

Based on density functional theory within the generalized gradient approximation, Sn-doped wurtzite ZnO transparent conducting oxide (TCO) was investigated, where structures relaxations, formation energies, and electronic structure of Sn doped in ZnO are studied. It was found that the lattice parameters of the Sn-doped ZnO increased with increasing Sn concentration. The substitutional Sn (SnZn) atom has low formation energy and introduces impurity levels below the conduction band minimum. Also, substitutional Sn atoms contribute significantly delocalized s orbitals in the conduction band states, which are expected to increase the conductivity of the material. Additionally, with increase of Sn concentration, the band gap is narrowed. We further identify that the lower concentration of heavily doped of Sn, the conductivity of ZnO is stronger. The calculated results are helpful to gain a systematic understanding of structure, electrical properties of Sn-doped ZnO transparent conducting oxide.