Metal-rich Au-silicide nanoparticles for use in nanotechnology

We present a route to functionalize chemically and magnetically silicon surfaces by a local passivation, taking advantage of Stranski-Krastanov growth mode of the Au-Si(111) system. Metal-rich Au-silicide nanoparticles, supported on a Si-rich two-dimensional Au-silicide layer, are obtained. Subsequently deposited Co is used to form magnetic nanostructures. The two Au silicides display a different chemical reactivity with Co enabling the fabrication of localized magnetic Co nanodots. These magnetic nanostructures can be aligned along step bunches of a vicinal Si(111) surface. By varying the growth parameters, the particle density can be tuned from 10(9) to the low 10(12) dots/in.(2).