The Influence of Ta underlayers on the structure of TiO2 thin films deposited on an unheated glass substrate

Highlights: ► Anatase TiO2 films were successfully obtained on unheated glass substrates. ► Crystallization of TiO2 thin films using Ta underlayers. ► Ti seed layer effect on the Ta underlayer crystallization. ► Anatase TiO2 films were also obtained on Ta/Ti underlayers without annealing. - Abstract: The influence of Ta underlayers on the structures of TiO2 thin films grown onto unheated glass substrates by radio frequency magnetron sputtering has been studied and compared. The crystal, electronic, and surface structures of fabricated TiO2 films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy, respectively. The X-ray diffraction results and valence band spectra by X-ray photoelectron spectroscopy revealed that the fabricated TiO2 films on the unheated glass substrate with a highly crystallized β-Ta underlayer showed an anatase structure, whereas the TiO2 film grown directly onto glass or onto a poorly crystallized Ta film showed an amorphous one. The results showed that the crystallized anatase TiO2 films were successfully obtained on glass substrates using the Ta underlayers without substrate heating and additional annealing.