Position-controlled carbon nanotube growth on single iron nanoparticles prepared by electron beam-induced chemical vapor deposition

Position control during carbon nanotube (CNT) growth is critical for CNT device application. We have developed a technique for precisely positioning a single iron nanoparticle on a substrate using electron beam-induced chemical vapor deposition (EB-CVD) with ferrocene source gas. A single-walled carbon nanotube (SWNT) preferably grew on the iron nanoparticle. EB-CVD makes it possible to grow 3D nanoscale structures at an exact location (Koops, et al., 1988). Such nanoscale 3D structures can be used to trigger catalytic growth of carbon nanotubes. We prepared ferrocene-based amorphous carbon nanodots containing iron by using EB-CVD. Vacuum annealing of the nanodots segregated the iron, resulting in a single iron nanoparticle inside each nanodot (Fujita et al., 2002). This was followed by oxygen ashing to remove the surrounding amorphous carbon. Carbon nanotube growth was triggered on a single iron nanoparticle by using ethanol CVD.