Epitaxial growth of TiO_2 thin films on SrTiO_3, LaAlO_3 and yttria-stabilized zirconia substrates by electron beam evaporation

摘要

Epitaxial anatase, rutile and mixed (brookite and anatase) TiO_2 thin films have been obtained by reactive electron beam evaporation. Anatase TiO_2 thin films have been prepared on LaAlO_3 (LAO) and SrTiO_3 (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, TiO_2 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℃ while the pure rutile phase has been obtained at a substrate temperature of 900℃ 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.