Characterizations and optical discussions of thermally evaporated titanium dioxide thin films

Titania thin films of 100 nm thick have been deposited from TiO₂ powder on glass substrates under vacuum ≈2 × 10⁻⁴ Torr by thermal evaporation technique. XRD, FE-SEM, and EDX analyses of samples confirm the amorphous nature, nano granular morphology and presence of Ti-and-O elements. Absorption coefficient spectra have been derived from UV–Vis spectrophotometric measurements. Direct and indirect optical bandgap energies are obtained as 3.87 eV and 3.33 eV, respectively. Various linear and nonlinear parameters have been investigated. The refractive index has been experimentally and theoretically estimated using different models. Dispersion and oscillator energies are found to be 21.54 eV and 6.04 eV, respectively. Static refractive index, oscillator wavelength and oscillator strength values have been also evaluated as 2.13, 190 nm, 1.96 × 10¹³ m⁻², respectively. First- and third-order optical susceptibilities and nonlinear refractive index have been determined as 0.37, 3.41 × 10⁻¹² and 6.04 × 10⁻¹¹ esu, respectively. According to current findings, TiO₂ films can be employed in many optoelectronic and photonic applications.