Electronic and optical properties of W-doped SnO2 from first-principles calculations

The electronic and optical properties of W-doped SnO2 are investigated by first-principles calculations in this work. The results show that the Fermi level shifts into the conduction band and the compound exhibits n-type metallic characters with high conductivity when W atoms substitute Sn atoms. As for defect cases, oxygen vacancies increase the density of states near the Fermi level resulting in a possible increase in the conductivity of W-doped SnO2, while the Sn vacancies make the Fermi level shift into the valence band and narrow the band gap. And the formation energy analysis indicates the possibility of W dopant and related defects forming in SnO2 crystal. The W-doped SnO2 shows high optical anisotropy, and the blue-shift of optical spectra can be observed. Additionally, the increased absorption in the visible region can be expected with the presence of oxygen vacancies in the crystal. (C) 2011 Elsevier B.V. All rights reserved.