Cutting single-walled carbon nanotubes with an electron beam: Evidence for atom migration inside nanotubes

The controlled cutting of single-walled carbon nanotubes (SWNT) by using a high-energy electron beams, is discussed. The cutting was performed on bundles of SWNTs in a field-emission transmission electron microscopes (TEMs), and temperature of 600-700°C was chosen to ensure high mobility of interstitials and to prevent their agglomeration, which lead to a rapid destruction of the tubes. The maximum possible cutting speed on a SWNT bundle beam parameters (300 keV, 1×104 Acm-2) was approximately 0.3 nms -1. The stability of nanotubes under irradiation was governed by the generation and annealing of vacancy-inter-stitial pairs. The cutting was achieved by slowly moving the focused beam spot from the edge across the bundle. This techniques of cutting SWNT at high electron energies provides the high lateral precision of approximately one nanometer.