Ion implantation based selective synthesis of silica nanowires on silicon wafers

A new method for selective growth of silica nanowires on silicon wafers is demonstrated by using ion implantation through a mask. Pd ions are implanted into Si (100) to form nanoclusters of Pd. The nanoclusters get activated and act as catalyst silicide seeds for nanowire growth, when heated in an open tube quartz furnace, using Ar as carrier gas. Silica nanowires grow selectively only on the implanted region. The vapor-liquid-solid model of nanowire formation is shown to be valid. This method facilitates controlled localized and directed bottom-up growth of silica nanowires and may enable applications such as in on-chip optoelectronics, biosensors, microantennae, and metallic nanotubes.