Electrostatic sol-spray deposition (ESSD) and characterisation of nanostructured TiO2 thin films

A novel film fabrication technique, i.e. electrostatic sol spray deposition (ESSD), has been used in this study to prepare TiO2 thin films of various surface morphologies and crystalline structures. Scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and UV/Vis absorption spectroscopy were employed to characterize the as-deposited and annealed TiO2 thin films. It has been found that silicon dopant can increase the anatase-to-rutile phase transformation temperature up to about 1050 degrees C, Two possible mechanisms are proposed to explain the phase stabilisation effect, i.e. reduction of the oxygen vacancy concentration by dissolution of SiO2 in the TiO2 lattice and segregation of a SiO2 second phase. The energy bandgap of amorphous SiO2 doped TiO2 films decreases with increasing annealing temperature. (C) 1999 Elsevier Science S.A. All rights reserved.