Rutile-type titanium oxide films synthesized by filtered arc deposition

A filtered arc-deposition system was used to synthesize titanium oxide films by evaporating titanium ions in an oxygen environment. Fourier transform infrared spectroscopy and X-ray diffraction analysis show that the films exhibit the rutile-type structure. X-ray photoelectron spectroscopy reveals that a small amount of Ti²⁺ and Ti³⁺ still exists although Ti⁴⁺ is the main component in the films. The preferred orientation of the films is dependent on the substrate bias and oxygen pressure. Titanium oxide films with (101) and (002) preferred orientation were prepared by changing substrate bias and oxygen pressure. Ultraviolet–visible absorption spectroscopy was used to determine the optical band gap of the prepared films. The results show that the band gap of the films prepared under zero substrate bias is 2.39 eV. When the substrate bias is larger than −100 V, the optical band gap of the films is about 3.33 eV.