Synthesis of Vertically Aligned Single- and Double-Walled Carbon Nanotubes without Etching Agents

High Resolution Image Download MS PowerPoint Slide The number of graphene shells on carbon nanotubes (CNTs) can be rationally controlled to yield high-density, vertically aligned single- and double-walled CNTs. This was obtained by thermal chemical vapor deposition at 700 °C without the use of etching agents such as water, oxygen, or plasma. The key factors for this success are controlled dissociative adsorption of acetylene (C 2 H 2 ) molecules and subnanometer thickness control of the Al/Fe/Mo trilayer films. We propose that an Al concave meniscus confines the actual growth surface areas of Fe/Mo catalytic nanoparticles and enables the control of the number of graphene shells on CNTs.