Epitaxial growth of TiO2 thin films on SrTiO3, LaAlO3 and yttria-stabilized zirconia substrates by electron beam evaporation

Epitaxial anatase, rutile and mixed (brookite and anatase) TiO2 thin films have been obtained by reactive electron beam evaporation. Anatase TiO2 thin films have been prepared on LaAlO3 (LAO) and SrTiO3 (STO) substrates of (100) and (110) orientation. The epitaxial relationship between anatase films (A) and (110) LAO/STO substrates is (012) A ∣∣ (110) LAO/STO, [100] A ∣∣ [001] LAO/STO. The anatase films were transformed into a cubic structure similar to TiO when in situ exposed to an electron beam. On the other hand, TiO2 thin films with a mixture of epitaxial anatase and brookite grains have been grown on (100)-oriented yttria-stabilized zirconia (YSZ) at a substrate temperature of 600 °C while the pure rutile phase has been obtained at a substrate temperature of 900 °C on (100) YSZ. The crystalline structure and surface morphology of the thin films were investigated by X-ray diffraction, transmission electron microscopy and atomic force microscopy. The crystallographic reason for the epitaxy between anatase films and perovskite substrates is discussed.