Zero-Dimensional Nanodots on One-Dimensional Nanowires: Reductive Deposition of Metal Nanoparticles on Silicon Nanowires

We review herein the surface chemical properties of silicon nanowires (SiNWs) and show how SiNWs can be used as platforms in doing chemistry in the nanorealm. In particular, the surfaces of HF-treated SiNWs (which are H-terminated) exhibit interesting chemical reactivities towards reductive deposition of metal ions such as silver, copper, palladium, etc., giving rise to metal particles or aggregates on the SiNW surfaces. By varying the concentration of the metal ions in solution, nanostructures of these metals of different shapes, sizes, and morphologies can be fabricated. The reductive growth of ligated Au–Ag clusters of single size, shape, composition, and structure, on the SiNWs was also investigated. Two interesting phenomena, the sinking cluster and the cluster fusion processes, were observed by TEM. These assemblies of metal nanoparticles on silicon nanowires may be considered as zero-dimensional nanodots, on one-dimensional nanowires. It is hoped that fabrication of these metallic nanodots on silicon nanowires will lead to new and novel composite materials of importance in nanotechnology.