Ab initio study on the electronic, optical and electrical properties of Ti-, Sn- and Zr-doped ZnO

We present a comparative study on the structural, electronic, optical and electrical properties of Ti-, Sn- and Zr-doped ZnO using density functional theory and semi-classical Boltzmann theory. It was found that the Ti- and Zr-dopants improve the crystal stability of ZnO, whereas Sn-dopant could lead to some extent to crystal structure distortion. The energy band gap of the Ti-, Sn- and Zr-doped ZnO is significantly expanded. The impurity states of Ti- and Zr-dopants induce strong absorption only in the IR-light range, while those of Sn-dopant induce strong absorption in the visible region. The calculated electrical conductivities show that Ti- and Zr-doped ZnO exhibit desirable values. The results demonstrate that Ti- and Zr-doped ZnO systems could be useful for transparent conducting oxide applications.