Silver nanostructures on a c(4x2)-NiOx/Pd(100) monolayer

The growth, morphology and epitaxial relationship of Ag nanostructures deposited onto the c(4 x 2)-NiOx/Pd(1 0 0) surface have been investigated by photoemission (both core and valence levels), scanning tunneling microscopy and angle-scanned photoelectron diffraction. Small Ag nanoparticles are obtained on the terraces, whereas the tendency of Ag to decorate the step edges can lead to the formation of extended nanowire-like features. The Ag nanoparticles adopt a fcc structure epitaxially related to the substrate according to the following relationship: Ag(1 0 0)[0 0 1]/Pd(1 0 0)[0 0 1], while by means of STM we have found that the shape of the islands is typically rectangular with the edges running along the [0 1 1] directions. According to the reported data, the NiOx ML is locally disrupted in the vicinity of the Ag nanoparticles so that the c(4 x 2)-NiOx/Pd(1 0 0) surface cannot be considered as an efficient template to stabilize metal nanoparticles against Ostwald ripening phenomena. (C) 2007 Elsevier B.V. All rights reserved.