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.