Enhancing the crystallinity and surface roughness of sputtered TiO2 thin film by ZnO underlayer

TiO2 and TiO2/ZnO double layer films were sputtered on glass substrates. It was found that a thin ZnO underlayer is helpful for tailoring the microstructure and surface morphology of the TiO2 film. By applying a 70-nm-thick ZnO underlayer, a TiO2 thin film of 100 nm in thickness with well crystallized anatase phase and rough surface was successfully fabricated without heating the substrate. Relatively high photo-catalytic activity and good hydrophilic properties were observed in such TiO2/ZnO double layer films.