Effect of substrate temperature on the epitaxial growth of Au on TiO2(1 1 0)

We have studied the effects of substrate temperature on the epitaxial growth of Au on TiO2(1 1 0) surface by combined high resolution scanning electron microscopy and electron backscatter diffraction. The Au was evaporated under UHV conditions onto stoichiometric and unreconstructed (1×1) TiO2(1 1 0) surfaces. Two deposition conditions were used consisting of RT deposition followed by annealing at 775 K and direct deposition at 775 K. Two different epitaxial orientations have been observed for the two conditions. After room temperature deposition and annealing, the epitaxial orientation relationship is (1 1 1)Au//(1 1 0)TiO2 with 〈1 1 0〉Au//[0 0 1]TiO2. While for direct deposition at high temperature the epitaxial orientation relationship is (1 1 2)Au//(1 1 0)TiO2 with 〈1 1 0〉Au//(0 0 1)TiO2. For both orientations, two epitaxial variants are observed which are rotated from each other by 180° around the TiO2(1 1 0) surface normal. These two variants are in a twin orientation relationship. For the high temperature deposition, extensive (1 1 1) twinning of the Au islands is observed which are the boundaries separating two orientation variants.