Selective functionalization of Si(111) and Ag(110) surfaces for preparation of Co nanostructures

Si(111) and Ag(110) surfaces were nano-structured and functionalised in two different ways. Vicinal Si(111), re-arranged into regular terraces and step-bunches, were used as a template for the controlled growth of gold-rich gold-silicide nanodots. Under suitable growth conditions, these nanodots can be aligned along the step-bunches. In contrast to the nanodots, a silicon-rich gold-silicide was formed on the terraces. Different chemical reactivities of the silicides with respect to cobalt are expected and give rise to either magnetic or non-magnetic Co areas. The Ag(110) surface was functionalised with parallel one-dimensional silicon nanowires (NWs) oriented along the [-110] direction of the substrate. The deposition of a sub-monolayer coverage of cobalt at room temperature leads to preferential Co adsorption on the silicon nanowires.