Superhydrophilic stability enhancement of RF co-sputtered Ti xSi 1− xO 2 thin films in dark

Abstract

Ti x Si 1− x O 2 compound thin-film systems were deposited by reactive RF magnetron co-sputtering technique. The effect of Ti concentration on the hydrophilicity of Ti x Si 1− x O 2 compound thin films was studied and it was shown that the films with Ti 0.6Si 0.4O 2 composition possess the best hydrophilic property among all the grown samples. Surface ratio and average roughness of the thin films were measured by atomic force microscopy (AFM). Surface chemical states and stoichiometry of the films were determined by X-ray photoelectron spectroscopy (XPS). In addition, XPS revealed that the amount of Ti–O–Si bonds in nanometer depth from the surface of the Ti 0.6Si 0.4O 2 films was the maximum, which resulted in the most stable superhydrophilic property. According to XRD data analysis for the pure TiO 2 films, the polycrystalline anatase phase was formed with an average grain size of about 15 nm. Moreover, amorphous phase was also formed for the Ti x Si 1− x O 2 compound systems due to presence of silicon in the films. Finally, optical properties of the films such as transmission, reflection and band gap energy were investigated using UV–vis spectrophotometry. It was found that the transmittance of the films was decreased with increasing Ti concentration in the films.