In situ observation of the initial growth process of carbon nanotubes by time-resolved high resolution transmission electron microscopy.

Abstract

We succeeded in plan-view dynamic observation of the initial formation process of carbon nanotubes from beta-SiC( 1 1 1) surfaces by time-resolved high resolution transmission electron microscopy. At 1360 degrees C, the flakes of graphite layers of a fibre orientation were formed on the SiC( 1 1 1) surfaces. From the graphite layers, carbon nanotubes were formed perpendicular to the ( 1 1 1) plane of the SiC. A scanning tunnelling microscopy observation showed that the end of carbon nanotube was closed. These results indicate that the caps of the carbon nanotubes are formed by a lift of a part of the graphene along the [ 1 1 1] direction of the SiC through generation of pentagons and heptagons. Two types of carbon nanotube, single-wall and double-wall, were observed in plan-view images. Different image intensity between an outer ring and an inner ring in double-wall nanotubes suggests that the inner layers of multiwall nanotubes are formed after the outer ones.