Deposition of Titania-containing Diamond-like Carbon Nanocomposite Films by Sputtering-assisted Chemical Vapor Deposition

Titania-containing diamond-like carbon (DLC) nanocomposite films were prepared by sputtering-assisted plasma chemical vapor deposition. With titanium-oxygen species sputtered from titania (TiO2) target by argon using a radio-frequency (RF) power, DLC films were simultaneously grown on the negatively-biased substrate by plasma chemical vapor deposition of acetylene gas using a pulsed direct-current (DC) power. By adjusting the Ar/acetylene gas concentration, both TiO2 and TiC nanoparticles could be incorporated in the DLC films. TiO2 nanoparticles were mainly formed in the DLC matrix with Ti-O bond being the dominant bonding for Ti in the DLC films. Furthermore, the amount of TiO2 and TiC nanoparticles embedded in the DLC film increased with the increase of Ar concentration in the gas. The TiO2-DLC nanocomposite films deposited at 80% Ar exhibited a high hardness of around 13 GPa at a relatively low stress and, particularly, a fast rate of turning super-hydrophilic by reaching zero degree of water contact angle under 40 min of ultraviolet irradiation.