Effect of TiN thin films deposited by oblique angle sputter deposition on sol-gel coated TiO2 layers for photocatalytic applications.

• TiN/TiO 2 bilayers fabricated on glass by oblique angle sputtering and sol-gel deposition. • Surface morphology of the top TiO 2 layer modified by the TiN sub-layer. • Higher photocatalytic activity of TiN/TiO 2 bilayer than the TiO 2 monolayer. TiO 2 monolayer and TiN/TiO 2 bilayer coatings were deposited on soda-lime glass prepared by mixing two techniques, TiO 2 was deposited by sol-gel dip-coating and TiN film was deposited by oblique angle deposition using reactive magnetron sputtering at α=45° Structural analysis showed typical peaks of TiO 2 anatase phase and cubic (Na-Cl type) structure of TiN. Roughness value of 3 nm was obtained for the TiN/TiO 2 bilayer film with a rise and elongated grains size. It was found that the optical band gap energy decreases after coupling the TiN sub-layer which is explained by the incorporation of N atoms into TiO 2 structure. At constant UV irradiation time, the photo-degradation of methylene blue rate increased for TiN/TiO 2 film by 4 % compared to TiO 2 film. [ABSTRACT FROM AUTHOR]