Morphological characterization of TiO2 thin films

Films prepared by reactive magnetron sputtering always present some structural and morphological heterogeneities.In this work, optical parameters, n(λ), k(λ) and E₀, of TiO₂ thin films were obtained, using only optical transmittance measurements. Films were described according to Abèles's model. Using a mono-oscillator type dispersion curve for the refractive index and a Lorentzian type curve for the absorption coefficient, we were able to demonstrate that the films were optically equivalent to a porous layer, with some dispersion in film thickness.The detailed analysis of the experimental transmittance data, fitted between 330 nm to 2200 nm, also enabled us to correlate the effective refractive index of each film with its deposition conditions.