Raman spectroscopy of sol–gel derived titanium oxide thin films

Abstract

Raman spectra of TiO 2 films prepared via the sol-gel process were studied by UV and visible Raman spectroscopy. The evolution of the phases of TiO 2 films during annealing was investigated, and the relative intensities of the Raman bands excited with 325 nm were found to be distinct from those of the bands excited with 514 nm. The transmittance and FTIR spectra of the films annealed at different temperatures were characterized. The crystallization process of the powders and thin films treated by different annealing methods were also studied with Raman spectroscopy. The results show that the change in the relative intensities is caused by the resonance Raman effect. The anatase to rutile transition of the powder occurs at 700 • C, while that of the thin film occurs at 800 • C. The analysis of Raman band shape (peak position and full width at half-maximum) after conventional furnace annealing and rapid thermal annealing indicates the influence of the non-stoichiometry and phonon confinement effect.

Characteristics of the mechanical milling on the room temperature ferromagnetism and sensing properties of TiO2 nanoparticles

“…The strongest peaks at 144 cm −1 , 520 and 639 cm −1 due to anatase phase are in agreement with the one reported in Ref. [34]. An increase of milling time induces a shift in the peak positions to higher wavenumbers.…”

Photochemical activity of TiO2nanotubes

“…and 824 cm −1 [11]. Most of the active Raman modes observed in our experiments were found to have energies very close to the aforementioned spectra.…”

Surface reconstruction, oxygen vacancy distribution and photocatalytic activity of hydrogenated titanium oxide thin film

“…Moreover, there are a number of reports where the strongest Raman active mode for anatase at 634-640 cm À1 was resolved [50,51]. Also, it is important to notice that the E g mode is considered as the main Raman mode in anatase [49], even though the intensities of other modes can be relatively higher [52]. This phenomenon is ascribed to UV nature of the incident laser, i.e., ''UV resonance Raman effect, because the laser light at 325 nm is in the electronic absorption region of TiO 2 '' [52].…”