Electronic and luminescence properties of sputter-deposited TiO₂ nanostructures

TiO₂ nanostructures are synthesized here by a radiofrequency magnetron sputter deposition technique using tin as a catalyst. The catalyst seeding and the sputter deposition are performed at ambient temperature. The growth of TiO₂ is carried out in a mixed Ar + O₂ and Ar + N₂ atmosphere and is found to comprise pure anatase. The morphologies of the obtained TiO₂ nanostructures are characterized using scanning electron microscopy. The electronic structures are investigated by X-ray absorption near-edge structure spectroscopy. The chemical compositions are analyzed using X-ray photoelectron spectra analysis, which indicates the presence of Ti³⁺. The luminescence properties are examined using cathodoluminescence spectroscopy. Five peaks are resolved from the luminescence data, indicating emissions of oxygen vacancies, F, F⁺, band-to-band emission and self-trapped excitons on TiO₆.