Optical properties of SiO_2–TiO_2 composite films

Optical properties of ion-beam sputter deposited SiO₂–TiO₂ composite films were examined in terms of composition dependence of the optical parameters, optical energy gap, and absorption character of these films. The complex refractive index of SiO₂ film in the nondispersive region (λ > 310 nm) was 1.48–i0.0000, and for TiO₂ (at λ > 525 nm) the index was 2.39–i0.0000 and the corresponding energy gaps 9.2 and 3.5 eV, respectively. Composite films of SiO₂–TiO₂ exhibited a continuous change in their optical properties. SiO₂-like optical properties were dominant for the volume concentration of ${\mathrm{C}}_{{\text{TiO}}_2}\le 0.25$ and TiO₂-like at higher concentrations.