Synthesis and structure characterization of cluster assembled titania films produced by supersonic cluster beam deposition

Nanostructured titanium dioxide thin films were deposited by a pulsed micro plasmacluster source (PMCS) technique. As-deposited amorphous films were annealed at temperatures from 200 deg.C to 800 deg.C under ambient conditions. Amorphous-to-anatase and anatase-to-rutile phase transitions were revealed by X-ray diffraction. It was observed that the onset of the anatase-to-rutile phase transition occurs below 600 deg.C, which is significantly lower than that in TiO2 single crystals. Moreover, Raman studies show that this structural transformation depends upon the duration of the annealing treatment. Mechanisms of phase transitions have been discussed based on experimental results obtained. (author)