Enhanced Photo-Induced Property of LPCVD-TiO<SUB>2</SUB> Layer on PCVD-TiO<SUB>x</SUB> Initial Layer

Abstract

Plasma-assisted chemical vapor deposition (PCVD) was applied for amorphous TiO x deposition on Pyrex-glass substrate at low temperature below 90°C to control orientation of anatase- TiO 2 layer by low pressure chemical vapor deposition (LPCVD) using TTIP-single precursor. Preferentially <112>-oriented anatase- TiO 2 layer was successfully deposited with the orientation ratio as high as 68% on the initial layer of the thickness around 70 nm. Contact angle water was quickly decreased by UV-irradiation on the highly <112>-oriented TiO 2 layer comparing with the layer directly deposited on glass, whereas surface roughness on the former was significantly reduced in comparison to that on the latter. Methyleneblue (MB) aqueous solution with the concentration of 2 mmol/L was used to evaluate photocatalytic property on the layer. Rate constant of MB-decomposition via first order kinetics increased with the orientation ratio above 60% was resulted in 2.3 × 10 -1 min -1 for the layer with <112>-orientation ratio of 68%, whereas the constant was 2.8 × 10 -3 min -1 for the layer directly deposited on glass.