The influence of metal interlayers on the structural and optical properties of nano-crystalline TiO2 films

► TiO2-M-TiO2 (M = W and Co) multilayer films with pure anatase phase have been deposited on glass substrates. ► Compared with pure TiO2 film, the crystallization temperature for TiO2-M-TiO2 films decreased significantly to 500 °C. ► The optical band gap of TiO2-M-TiO2 films became narrower than that of pure TiO2 film. ► The crystallization of TiO2-M-TiO2 films was attributed to the structural deformation due to the oxidation of metal layers.