Crystallization of sol-gel and mesoporous anatase titania films studied by THz spectroscopy

Mesoporous and dense sol-gel titania films have been synthesized and processed in similar conditions to make a comparative study of crystallization to anatase in porous and dense samples. We have performed a correlative analysis combining THz spectroscopy with synchrotron radiation, variable angle incidence infrared spectroscopy, spectroscopic ellipsometry and grazing incidence X-ray diffraction to characterize the structure of titania films as a function of thermal processing conditions. THz spectra have shown that small anatase crystalline clusters are already present in the as-deposited samples, and both crystallization and growth process are favored in the mesoporous films. Moreover, the analysis by X-ray diffraction and variable angle incidence infrared spectroscopy has allowed identification of the presence of small textures in the samples.