X-ray photoelectron spectroscopy analysis of nitrogen-doped TiO2 films prepared by reactive-ion-beam sputtering with various NH3/O2 gas mixture ratios

Abstract

Nitrogen-doped TiO2 films were prepared by reactive ion-beam sputtering deposition (IBSD) in a mixed atmosphere ofNH3 and O2 at a substrate temperature of 400 offiC. X-ray photoelectron spectra revealed the presence of six ions, i.e., N3-, N2-, N1- N+, N2+, and N3+, respectively, in the films. The amorphous films had complex, randomly oriented chemical bonds. The Tauc-Lorentz model was employed to determine the bandgap energy of the amorphous films prepared using different NH3/O2 gas mixing ratios by ellipsometry. In addition, the optical constants of the films were measured. With the increase in the NH3/O2 gas mixture ratio to 3.0, the bandgap of N-doped TiO2 narrowed to ~2.54 eV.