Microstructure and visible-photoluminescence of titanium dioxide thin films fabricated by dual cathodic arc and nitrogen plasma deposition

We report the concurrent use of plasma nitridation with cathodic arc deposition to fabricate N-doped TiO₂ thin films on Si (100) wafers. The microstructures and optical properties are investigated. Our results reveal that the incorporation of a small amount of nitrogen in TiO₂ enhances its visible photoluminescence (PL) significantly giving rise to peaks located at 472, 488, and 548 nm. Our study suggests that plasma nitridation in conjunction with cathodic arc deposition is an effective method to introduce N into TiO₂ and to improve the optical properties of the thin films. The effects and underlying mechanism are discussed in details.