Ag on Au/Si(111):mInterfacial interactions on a submicrometer scale

The interaction of Ag with a ($\sqrt{3}$×$\sqrt{3}$)R30°-Au/Si(111) interface containing Au microparticles is studied by means of photoelectron spectromicroscopy with the goal being to understand the microscopic aspects of the interface evolution. The distribution and the composition differences of the two phases are evaluated from the contrast in the Au, Ag, and Si maps and by analysis of the spatially resolved Au 4f, Si 2p, and Ag 3d photoelectron spectra. The surface processes controlling locally the evolution of the bimetal Ag+Au/Si interface and the correlation between the Au chemical state and the reactivity of the phases are revealed and discussed.