Study of very thin TiO 2 films by high resolution transmission electron microscopy

Abstract

Very thin TiO 2 films were produced by the sol-gel method and a dip-coating process. The effect of annealing temperature on the films' microstructure was followed by high resolution transmission electron microscopy (HREM). At low annealing temperature (450 °C), amorphous TiO 2 and roughly circular anatase nanocrystals are clearly observed. At higher annealing temperatures, the amorphous part of the film tends to disappear and the nanocrystals are bigger. At high temperature (600–650 °C), the main growth mechanism seems to be coalescence of nanocrystals, which induces open porosity.