Amorphous titanium dioxide (TiO<sub>2</sub>) thin film has been prepared by a filtered cathodic vacuum arc technique at room temperature. It was concluded from the core level of Ti 2<i>p</i><sub>3/2</sub> (458.3 eV) and O 1<i>s</i> (529.9 eV) and their deviation in binding energy (ΔBE = 71.6 eV) that only one of Ti oxidation states, Ti<sup>4+</sup>, existed in the film and the film was of ideal stoichiometry. The film possessed high transmittance, which can reach as high as that of a quartz substrate, especially in the visible range, owing to its optical bandgap of 3.2 eV. The high refractive index (2.56 at 550 nm) and low extinction coefficient (~10<sup>−4</sup> at 550 nm) suggested that the film had a high packing density and a low scattering-center concentration. These good optical properties implied the film prepared by this technique was a promising candidate for optical application. Besides, the film was found to transform in the structure from amorphous to anatase crystalline when it was annealed at 300 °C, as evidenced by Raman and x-ray diffraction.
© 2004 Optical Society of America
Zhiwei Zhao, Beng Kang Tay, and Guoqing Yu, "Room-Temperature Deposition of Amorphous Titanium Dioxide Thin Film with High Refractive Index by a Filtered Cathodic Vacuum Arc Technique," Appl. Opt. 43, 1281-1285 (2004)