The formation, annealing and self-compression of carbon onions under electron irradiation

Electron irradiation-induced basal plane disordering in single- and multi-shell carbon nanotubes and onions is found to be inhibited at irradiation temperatures above 300 degrees C. Irradiation-induced defects anneal out due to the thermally activated migration of interstitials at elevated temperatures and leave behind perfectly coherent shells of high tensile stability. Continuous loss of atoms as a result of sputtering induces a surface tension which can be identified as the origin of the formation and self-compression of spherical concentric-shell carbon onions.