Metallic surface doping of SiO_x nanowires

Utilising active oxidation processes at higher temperatures and low O ₂ partial pressures, a dense layer of sub-stoichiometric silica nanowires can be readily fabricated directly from an underlying metal coated Si substrate. These unique surfaces are thermally and chemically robust, providing an ideal supporting substrate for secondary materials for a range of applications, including photocatalysis and sensing. In this report we discuss methods to incorporate volume and surface metallic dopants via ion implantation into and onto these unique nanostructures. At higher temperatures, these dopants form metallic nanoparticles on the nanowire surface and when re-subjected to an active oxidation environment result in the onset of secondary nanowire growth. The incorporation of metallic Er³⁺ ions is used to optically probe the doping properties, including incorporation and agglomeration. Evidence for metal dopant incorporation during the nanowire growth is presented suggesting that hierarchically doped nanostructured silica surfaces can be readily grown via simple thermal processing.