Abstract

TiO2 (rutile) single crystal plates with (001) and (110) orientation were immersed in an aqueous solution of Ba(OH)2 0.5 M at temperatures of 100 and 150 °C for 1 and 4 hours in order to grow BaTiO3 on them. SEM micrographs of the samples fabricated on the (001) surface of ruffle displayed isolated grains with an average height ranging from 200 nm at 100 °C to 700 nm 150 °C. On the other hand, samples with the (001) orientation exhibited no growth at 100 °C and only a few grains along lines attributed to the polishing process of the substrate at 150 °C. The image of backscattered electrons indicated that barium is concentrated on the grains in all cases. Only the (001) samples exhibited reflections of cubic BaTiO3, as indicated by x-ray diffraction, as well as distinct Ba signals under x-ray photoelectron spectrometry. These results agree with the hypothesis of a dissolution-precipitation growth mechanism, in which dissolution is possible for the (001) face, but not for the (110) one, which is the most stable of the low-index faces of this material. Similar treatments were applied to ZrO2:Y2O3 crystals, leading to no film growth.