Growth, Structure, and Stability of Au on Ordered ZrO2(111) Thin Films

The growth, electronic properties, and thermal stability of Au nanoparticles on ordered ZrO2(111) thin film surfaces were investigated by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), and synchrotron radiation photoemission spectroscopy (SRPES). The thin ZrO2(111) films were grown on a Pt(111) substrate. At room temperature, Au initially grows as 2D islands on the ZrO2(111) thin films up to 0.1 ML, followed by 3D growth with a number density of ∼1.4 × 1012 particles/cm2. The binding energy of the Au 4f peaks shifts monotonically toward a higher binding energy with decreasing the Au particle size by 0.4 eV, which can be attributed to the contribution from both the initial- and final-state effects. Au atoms most likely form Auδ− initially and become metallic states as the coverage increases. Thermal annealing experiments demonstrate that Au particles experience significant sintering before desorption from the ZrO2(111) surface. In addition, Au particles are more thermally s...