Investigation of microstructure evolution in Pt-doped TiO2 thin films deposited by rf magnetron sputtering

Pt-doped titanium dioxide or titania (TiO2) films were grown by rf magnetron sputtering and then annealed in the conventional thermal annealing (CTA) process. Raman spectroscopy was used to characterize the structure of the films deposited. The effect of sputtering parameters was studied in focus of the nucleation sites energies (influenced by the substrate temperature) and substrate bombardment energies (influenced by the sputtering pressure or rf power). The X-ray diffractions technique was used to investigate the structural variation after the films were annealed at different temperatures. It was found that 0.75% Pt-doped TiO2 film exhibits better thermal stability and smaller grain sizes than 0.35% Pt-doped TiO2 film, suggesting that the suppression of crystallization can be expected with a proper increase of Pt doping level. And the obtained optical transparency higher than 80% even after annealing has demonstrated the films' prospect for future developments.