title: Preparation and characterization of molecularly homogeneous silica-titania film by sol-gel process with different synthetic strategies.
abstract: Three silica-titania thin films with various degrees of molecular homogeneity were synthesized by the sol-gel process with the same precursor formula but different reaction paths. The dried films prepared by a single spin-coating process have a thickness of 500-700 nm and displayed no cracks or pin holes. The transmittances and refractive indices of the samples are >97.8% in the range of 350-1800 nm and 1.62-1.65 at 500 nm, respectively. The in-plane and out-of-plane chemical homogeneities of the films were analyzed by X-ray photoelectron spectroscopy and Auger electron spectroscopy, respectively. For the film with the highest degree of homogeneity, the deviations of O, Si, and Ti atomic contents in both in-plane and out-of-plane directions are less than 1.5%, indicating that the film is highly molecularly homogeneous. It also possesses the highest transparency and the lowest refractive index among the three samples.
authors.affiliation: Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan. sean.chen@cantab.net
authors.forename: Hsueh-Shih
authors.initials: HS
authors.lastname: Chen
authors.forename: Sheng-Hsin
authors.initials: SH
authors.lastname: Huang
authors.forename: Tsong-Pyng
authors.initials: TP
authors.lastname: Perng