TiO₂ FILMS PRODUCED BY ELECTRON BEAM VACUUM DEPOSITION FROM NANOMETRIC POWDER OBTAINED BY PECHINI’S METHOD

Resumo

Nanometric TiO₂ powders were obtained from low temperature calcination of a TiO₂ resin prepared using the Pechini’s method. Firing the TiO₂ resin at 500 °C/2h a powder with anatase phase was obtained, otherwise firing the TiO₂ resin at 700 °C/2h a powder with rutile phase was achieved as measured by X-ray diffraction (XRD). The anatase powder presented average particle size of 60 nm observed by Scanning Electronic Microscopy (SEM-FEG) micrographs and average crystallite size of 13 nm calculated from the XRD, while the rutile powder presented average crystallite size of 34 nm. Nanocrystalline TiO₂ films with good homogeneity and optical quality were obtained with 80 nm and 320 nm in thickness by Electron Beam Physical Vapour Deposition (EB-PVD) in vacuum on amorphous quartz substrates submitted at 350°C during the evaporation. The 80 nm-thick film presented average particle size of 140 nm and roughness (R_a) of 1.08 nm and the 320 nm-thick film showed average particle size of 350 nm and roughness (R_a) of 2.14 nm measured by Atomic Force Microscopy (AFM). In these conditions of deposition the films presented only anatase phase observed by XRD and MicroRaman spectroscopy.