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

We report on the growth of NiSi2-catalyzed amorphous SiO2 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.