Graphitized wavy traces of iron particles observed in amorphous carbon nano-pillars

We found that traces of iron nano-particles were graphitized in amorphous carbon nano-pillars fabricated by electron beam induced chemical vapor deposition (EB-CVD). The random walk of iron particle in the carbon nano-pillar caused the continued growth of wavy graphite tube just after the iron particle passed by, as a result of vacuum annealing at 800 C for 30 minutes. The origin of the iron nano-particle was the decomposed ferrocene basement for the carbon nano-pillar. The size of the amorphous carbon nano-pillar was controlled to have the minimum diameter of 5 nm by adjusting the electron current and supplement of the source gas. This small feature size of the nano-pillar strongly restricted the area for the movement of the iron particle, and thus the graphitized trajectory of the iron particle was revealed on a TEM image.