Growth of amorphous silica nanowires using nickel silicide catalyst by a thermal annealing process

We report on the growth of NiSi₂-catalyzed amorphous SiO ₂ nanowires by rapid-thermal-annealing of Ni(40 nm)/poly-Si(60 nm)/SiO₂(110 nm)/undoped Si substrate structures at 900 °C in N₂ ambient. The diameter of the nanowires is dependent on the diameter of the NiSi₂ catalyst particles; the former is about 16-45% smaller than the later. Considering the presence of the nanoparticles located at the tip of the nanowires, the growth behavior of the a-SiO₂ nanowires is described in terms of the generation of SiO vapor and the VLS mechanism.