Formation and chemical-physical characterization of metallic nanoclusters in ion-implanted silica

Implantation of metal ions in glass substrates leads, under certain circumstances, to the formation of nanometer-radius colloidal particles in a thin surface layer. The nonlinear optical properties of such colloids, in particular the enhancement of optical Kerr susceptibility, suggest that the ion implantation technique may play an important role for the production of all-optical switching devices. The formation of these particles in silica mainly depends on the reactivity of the substrates and of the implanted ions, on the concentration of the metal, on its mobility. In spite of the great interest due to possible applications in device construction, processes governing the chemical and physical interactions between the dielectric host and the implanted metal are far from being completely understood. In this paper particular emphasis is given to the study of chemical interactions between implanted metals and silica hosts. Results are reported for titanium, chromium, tungsten, copper, silver and platinum.