Synthesis of carbon nanotubes on graphene quantum dot surface by catalyst free chemical vapor deposition

The growth of carbon nanotubes (CNTs) on graphene quantum dot surface has been explored using acetylene as the carbon source in a catalyst free chemical vapor deposition process. Dynamic studies were conducted to observe the CNT growth. The obtained nanotubes have a diameter distribution of 10-30 nm and show medium graphitic quality. Transmission electron microscopy observations and dynamic studies indicate that the formation of CNTs follows a different mechanism from traditional growth models, in which a wire-to-tube process and self-assembling of CNTs are involved. On the basis of these observations, a tentative continuous growth model is proposed for the CNT growth. (C) 2013 Elsevier Ltd. All rights reserved.