Fabrication and properties of N-doped top layer of Ga2O3 films by magnetron sputtering

The β-Ga2O3 films with a top layer doping of nitrogen (N) were prepared by RF magnetron sputtering. The relationship of parameters (e.g. nitrogen flow rate and annealing atmosphere), microstructure, optical properties of N-doped top layer β-Ga2O3 films were studied by XRD, XPS, SEM, UV–VIS and PL. It is found that the crystal quality of the films was related to the N content and annealing atmosphere. The films had the smooth surface with the average roughness of ∼2 nm. The current films had a high transmittance over 85 % within the visible region but the band gap decreased. All these films emitted ultraviolet light under the incident light at 250 nm. Moreover, the Fermi level moved toward to the valence band by adding the N element, leading to the p-type doping characteristic.