Dispersion of titania TiO2-II high-pressure phase based on ellipsometric measurements.

The optical properties of scrutinyite type TiO 2 (TiO 2 -II) were calculated using Bruggeman effective media approximation for thin films containing epitaxial rutile and TiO 2 -II. For that TiO 2 thin films containing only epitaxial rutile and containing rutile together with TiO 2 -II were used. The films were synthesized using TiCl 4 and O 3 on r-plane and c-plane sapphire at 450 °C by atomic layer deposition. Films deposited on r-plane sapphire and containing only epitaxial rutile were used for the evaluation of the optical properties of rutile. The optical dispersion of TiO 2 -II was calculated from ellipsometric measurements using the pre-evaluated optical dispersion of rutile and implementing the Bruggeman effective media approximation for two-phase rutile + TiO 2 -II films. The refractive index of TiO₂-II was found to be lesser i.e. 2.61 when compared to 2.7 of epitaxial rutile phase for measurements performed at 633 nm. The absorption edge of TiO₂-II phase has been determined to be about 3.2 eV for indirect transitions, approximately close to that of rutile. [Display omitted] • Mixed rutile + TiO 2 -II film is turned to epitaxial rutile annealing it to 1000 °C. • Rutile dispersion and absorption edge are obtained using ellipsometry. • Bruggeman EMA is used to find optical parameters of one component in a mix. • Epitaxial TiO 2 -II phase optical dispersion is found. [ABSTRACT FROM AUTHOR]