The FTIR spectra for the film deposited on Si (111) for TiO2 films grown from sols (1) and (2) are shown in Fig. 5.
Curves A and B in Fig. 5b correspond to spectra recorded in the wavelength range 400±900 cm21 for the TiO2 films
deposited from sols (1) and (2), respectively. The rather weak and broad features observed in the spectra are identified with the bulk TiO2 skeletal frequency region. The spectra display features showing complex vibrations due to TiO2
and also Ti2O3. The vibration band at 871.8 cm21 is in reasonable agreement with the vibrational features observed
in the PL data (Fig. 4, inset) corresponding to the (0±8) position. Other features in the spectrum also correlate with
those observed in PL fine structure. The FTIR signal of TiO2 (sol(2)) is lower in signal level due to the reduced thickness
of the film, but exhibits essentially the same features. The strongest signal comes from a resonance at 418.5 cm21 that
corresponds to the maximum PL signal at 314 nm (difference at 309.5 nm).