Investigation on ultrathin titanium oxide films synthesized by surface sol–gel method

Ultrathin titanium oxide films were synthesized on glass substrates by surface sol–gel method. The films were grown by sequential immersion in TiCl4 solution and water. The film morphology, structure and property were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–visible spectroscopy. The results indicate that the films grow at a rate of about 2–3 nm per cycle and present an island-like growth mode. The film show an amorphous state and not a strict equilibrium TiO2 structure. Furthermore, the film absorbance gradually increases with the depositing cycle.