Optical and transport properties of Sb-doped SrTiO3 thin films

Optically transparent SrTi1-xSbxO3 (=0.05, 0.10, 0.15, and 0.20) thin films with transmittances higher than 85% in the visible region have been grown on SrTiO3 substrates by pulsed-laser deposition. Unless overdoped, the film s possess a single-crystal phase and impurity conduction. The temperature d ependence of the resistivities shows a metal-semiconductor transition for t he film with x=0.05, and semiconducting behaviors for the films with x=0.10 and 0.15. The overdoped film with x=0.20 is an insulator. Sb concentration has a dominant effect on the electrical properties of the films, and the A nderson localization is probably the mechanism. X-ray photoelectron spectro scopy results indicate that the Sb impurity atoms provide donor electrons t o form impurity states within the band gap, which is responsible for the el ectrical localized impurity. The wide band gap and the low density of state s in the conduction band result in the transparency of the films. The disor der increases with Sb concentration, which is the main origin of the evolut ion of the electrical properties. (C) 2001 American Institute of Physics.