Effect of substrate temperature on the epitaxial growth of Au on TiO2(110)

We have studied the effects of substrate temperature on the epitaxial growt h of Au on TiO2(1 1 0) surface by combined high resolution scanning electro n microscopy and electron backscatter diffraction. The Au was evaporated un der UHV conditions onto stoichiometric and unreconstructed (1 x 1) TiO2(1 1 0) surfaces. Two deposition conditions were used consisting of RT depositi on followed by annealing at 775 K and direct deposition at 775 K. Two diffe rent epitaxial orientations have been observed for the two conditions. Afte r room temperature deposition and annealing, the epitaxial orientation rela tionship is (1 1 1)Au//(1 1 0)TiO2 with (1 1 0)Au//[0 0 1]TiO2. While for d irect 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 orientatio ns, two epitaxial variants are observed which are rotated from each other b y 180 degrees around the TiO2(1 1 0) surface normal. These two variants are in a twin orientation relationship. For the high temperature deposition, e xtensive (1 1 1) twinning of the Au islands is observed which are the bound aries separating two orientation variants. (C) 2001 Elsevier Science B.V. A ll rights reserved.