Thin films of TiO2 were grown onto (11▪2) sapphire and (001) LaAlO3 surfaces at 800C, using pulsed-laser deposition, and were characterized by means of transmission electron microscopy. The thin films which were grown onto LaAlO3 crystallized as anatase, while those grown on sapphire crystallized as rutile. The epitaxial relationship between the anatase thin film and the LaAlO3 substrate was (004)[110]A||(001)[110]L, and that between the rutile thin film and the sapphire substrate was (011)[111]R||(11▪2)[20▪1]S. The rutile thin films contained a high density of growth twins, with (101) and (011)T being the twin planes and [101] the twinning direction (where the subscript T represented the twinning plane). Neither of the epitaxial systems exhibited a good lattice match between film and substrate. A substantial similarity existed in the local atomic patterns of the substrate and the film in both systems. This was attributed to the formation of different TiO2 phases on different substrates.

High-Resolution Transmission Electron Microscopy Study of Defects and Interfaces in Epitaxial TiO2 Films on Sapphire and LaAlO3. Huang, J.Y., Park, B.H., Jan, D., Pan, X.Q., Zhu, Y.T., Jia, Q.X.: Philosophical Magazine A, 2002, 82[4], 735-49