Size-selected growth of ultrathin SiO2 nanowires on surface and their decoration by Au nanoparticles

We report about a simple, versatile, low-cost and high-throughput methodology for the size-selected growth of SiO2 nanowires on surfaces and on their surface decoration by Au nanoparticles. In contrast to a standard method involving the solid state reaction of thin Au films on Si at high temperature in presence of trace amount oxygen (resulting in the formation of SiO2 nanowires with a very high dispersion in diameters), the proposed method involves the same reaction between size-selected colloidal Au nanoparticles and the Si substrate. By microscopic analyses we demonstrate that, by such a method: 1) nanowires of very low diameter can be grown with respect to those originating by films; 2) the size dispersion of the obtained nanowires is much lower with respect to those originating by films; 3) the nanowires diameter can be finely tuned by controlling the colloidal nanoparticles starting size; 4) it is possible to decorate such nanowires by Au nanoparticles simply coating them by a Au film and inducing, by a thermal process, the dewetting of the film.