TiO2 waveguides thin films prepared by sol-gel method on glass substrates with and without ZnO underlayer

TiO2 thin films have been deposited on glass substrates with and without ZnO underlayer by sol-gel dip coating process. XRD patterns show the formation of anatase phase with the diffraction lines (1 0 1) and (2 0 0) in TiO2 /glass sample. In TiO2 /(ZnO/glass) sample, TiO2 is composed of anatase phase with the diffraction line (2 0 0) but the diffraction peaks of ZnO wurtzite are also well-defined. The determination of the refractive index and the thickness of the waveguiding layers has been performed by m-lines spectroscopy. The thickness of TiO2 thin films deduced by Rutheford Backscattering Geometry (RBS) agrees well with that obtained by m-lines spectroscopy. TiO2 /glass sample exhibits one guided TE0 and TM0 polarized modes. In TiO2 /(ZnO/glass) sample, only, TE0 single mode has been excited due to cutoff condition.