Properties of Titanium Dioxide Thin Films, Fabricated by Gel Methods

Titanium dioxide films obtained by gel method are investigated. Optical properties of the fabricated films, such as thickness, refractive index and thermo-optic coefficient were studied by the methods of integrated optics which use waveguide propagation of radiation along the film. The parameters of the films fabricated by sol-gel and gel methods were compared. It was established that the pores in the films made by gel method contain smaller amounts of water and therefore have higher density. Refractive index of gel films was determined by the resonant angle of the waveguide excitation, calculated using the optical waveguide dispersion equations and amounted to 2.1-2.4. This value is higher than in the case of using sol-gel technology for fabrication of thin films (1.5-1.8). By the reflection and transmission spectra obtained using spectrophotometer, it was found that films produced under cetrain parameters of technological regime have anisotropic properties. It was established that the presence of anisotropy is due to the structure of the film in the form of a linear oligomer. The structure and morphology of the gel films was studied by electron microscopy. It is shown that the resulting films have a porous structure that allows their doping with substances allowing to create elements of integrated optics, such as lasers, amplifiers, etc.

thin films, titanium dioxide (TiO2), sol-gel and gel process, integrated optics, birefringence