GROWTH OF RH ON AU(111) - SURFACE INTERMIXING OF IMMISCIBLE METALS

The growth of Rh on Au(111) was studied using UHV-STM and Auger electron spectroscopy. At room temperature, Volmer-Weber cluster growth was observed as expected from the surface energies and the immiscibility of Rh and Au below 650-degrees-C. After annealing to 400-degrees-C, the Rh Auger intensity decreased and STM revealed the formation of Au islands on the surface. Atomic-resolution images obtained after annealing showed a high density of defects due to Rh incorporation within the Au terraces and beneath the Au islands. The results demonstrate surface intermixing and growth by surface atom displacement and formation of substrate islands even for these immiscible systems.