ABSTRACT
High-energy beam irradiation can have beneficial effects in manipu-
lating the carbon nanotube morphology, especially when combined
with heat treatment. The manipulation is achieved through the
irradiation-induced displacement of carbon atoms from their
equilibrium positions. When the kinetic energy transferred from
incident particles to the carbon nuclei is larger than the displace
threshold, a carbon atom leaves its initial position and is pushed
far away from the nanotube or is quenched into a metastable defect
configurationa (see Fig. 10.1, for example). Hence, bombardment
with energetic particles can be used for the sputtering of atoms
Figure 10.1 Schematic of the most relevant processes in carbon nanotube tailoring by electron-beam irradiation. (a) Electron impact creating a defect
pair by displacing a carbon atom; the white sphere represents a vacancy
and the gray sphere an adatom. (b, c) Adatom and vacancy migration.
(d) Creation of a vacancy by sputtering the displaced atom. Reprinted
with permission from Krasheninnikov, A. V., and Nordlund K., Ion and
electron irradiation-induced effects in nanostructured materials, J. Appl. Phys., 107(7), 071301, 2010. Copyright 2010, American Institute of Physics.
in pre-defined areas, and successive sputtering treatment makes it
possible to alter the local (or larger-scale) geometry of nanotubes.
