Structural, Morphological, and Photocatalytic Comparison of TiO₂ Thin Films Deposited by RF Magnetron Sputtering at Room Temperature and 300 °C

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Çetin A., SIMSIR M., Tuzemen E. S., ÖZER A.

Cumhuriyet Science Journal, cilt.47, sa.3, ss.557-565, 2026 (TRDizin)

Özet

In this study, TiO₂ thin films were deposited onto glass substrates at room temperature and at a moderate substrate temperature of 300 °C by RF magnetron sputtering, and their structural, morphological, chemical, and photocatalytic properties were comparatively investigated. XRD analysis revealed that the film deposited at room temperature was fully amorphous, whereas the film deposited at 300 °C exhibited weak anatase reflections superimposed on an amorphous background, indicating the onset of crystallization. Cross-sectional SEM images confirmed the formation of a homogeneous film with an approximate thickness of 330 nm, while surface SEM observations showed a denser and more developed surface morphology for the film grown at elevated temperature. AFM measurements demonstrated that the film deposited at 300 °C possessed a markedly rougher granular surface. FTIR spectra revealed the characteristic Ti–O–Ti vibrational bands, confirming the formation of the TiO₂ network structure. Photocatalytic experiments showed that the TiO₂ film deposited at 300 °C achieved approximately 74% degradation of methylene blue under UV-A irradiation after 9 h, exhibiting significantly higher activity than the room- temperature film. This enhanced performance is attributed to the combined effect of incipient anatase formation and increased surface roughness. Overall, the results demonstrate that low-temperature structural evolution strongly influences the photocatalytic response of sputtered TiO₂ thin films, and that appreciable photocatalytic performance can be achieved at 300 °C without a separate post-deposition annealing step.