Selective synthesis of carbon nanotubes and multi-layer graphene by controlling catalyst thickness

Selective synthesis of carbon nanotubes (CNTs) and graphene was achieved by hot-filament chemical vapor deposition (CVD) using iron films as a catalyst at a temperature of 620 degrees C. The selective synthesis was performed in a very simple way, just by changing the catalyst thickness under the same CVD conditions. Only CNTs were obtained with Fe films of 5 nm and less, while multi-layer graphene was formed with the catalyst films of 20 nm and more. The thickness of multi-layer graphene can also be controlled by controlling the thickness of the catalyst further. (C) 2011 Elsevier B.V. All rights reserved.