Optical and electrical responses of magnetron-sputtered amorphous Nb-doped TiO2 thin films annealed at low temperature

Abstract Nb-doped TiO 2 (TNO) thin films were prepared by annealing at 300 °C for 30 min after a magnetron-sputter process. A laser-irradiated post-annealing Raman scattering analysis indirectly showed the possible formation of small size anatase TNO clusters within the thin film matrix Although the TNO thin films were not crystallized, oxygen vacancies were created by adding H 2 into the sputter gas during the deposition process. This improved the conductivity and carrier concentration of the thin films. As the ratio of H 2 in sputter gas is f(H 2 ) = [H 2 /Ar+H 2 ] = 10%, the carrier concentration of the amorphous TNO thin film reached 10 22 (cm −3 ) with the resistivity being about 10 −2 (Ω.cm). Even though a new methodology to decrease the fabrication temperature is not presented; this study demonstrates an efficient approach to shorten the annealing process, which ends prior to the crystallization of the thin films. Besides, in situ H 2 addition into the sputter atmosphere is proven to be a good solution to enhance the electrical conductivity of semiconductor thin films like TNOs, despite the fact that they are not well crystallized.