Photocatalytic antibacterial study of N-doped TiO₂ thin films synthesized by ICP assisted plasma sputtering method

Specific plasma engineering based synthesis can induce interesting photocatalytic antibacterial activities in TiO₂ films. This work presents the combination of pulsed DC (PDC) plasma with inductively coupled plasma (ICP) to synthesize undoped and nitrogen doped (N-doped) TiO₂ thin films using magnetron sputtering. The surface properties of resulting films were systematically analyzed in detail and correlated to the photocatalytic antibacterial activity against Gram negative Escherichia coli (E.coli). The addition of ICP source to PDC discharge generated TiO₂ films with enriched surface roughness due to the bombardment of highly activated species on the substrate. The ICP assisted films exhibited the morphology of nanoclusters with clear defined boundaries, higher O content and higher surface wettability. It was found that the films deposited with N-doping and addition of ICP source significantly increased the eradication of bacteria both in dark as well as in white light (artificial indoor light). Higher antibacterial activity of N-doped TiO₂ films in white light has been explained by photocatalytic degradation mechanism.