Pulsed laser deposited Nb doped TiO2 as a transparent conducting oxide

Nb doped TiO2 (Nb:TiO2) is a promising indium-free transparent conducting oxide. We have examined the growth of Nb:TiO2 thin films by pulsed laser deposition (PLD) on SrTiO3, LaAlO3, and fused silica. For <004> oriented anatase Nb:TiO2 films grown on SrTiO3 by PLD at 550 °C, the conductivity can be as high as 2500 S/cm. A nearly thickness independent conductivity for Nb:TiO2 demonstrates that the conductivity is a bulk property and not a substrate interface effect. In addition, Nb:TiO2 films deposited at room temperature were annealed at temperatures up to 750 °C in either vacuum or 1.3 × 10− 3 Pa O2. For these films, conductivities as high as 3300 S/cm on SrTiO3 and 85 S/cm on LaAlO3 substrates were obtained for the highest temperature vacuum anneals, albeit with some loss in transparency.