ADSORPTION OF SB ON AG(111) STUDIED USING LEED, AES AND XPS

The growth of Sb overlayers on Ag(111) has been studied using LEED, AES and XPS from sub-monolayer to multilayer coverages as a function of deposition temperature. At room temperature, growth was found to be by the Franck-van der Merwe (layer-by-layer) mechanism. Two distinct ordered structures were seen after annealing of the deposited layers, a (square-root 3 x square-root 3)R30-degrees at low coverage and a (2 square-root 3 x 2 square-root 3)R30-degrees at coverages above 1.5 monolayers. The first of these structures is thought to involve substituted Sb into the first layer of Ag atoms, forming a surface alloy. The second structure may be due to the formation of an Sb overlayer on top of the Sb substituted layer. Small core level shifts were observed in the XPS spectra of the deposited surfaces.