Boron nitride nanotube growth defects and their annealing-out under electron irradiation

Growth defects, namely undulating, dangling BN sheets, dislocation edges, and local irregularities in BN hexagonal sheet spacing have been observed in boron nitride multi-walled nanotubes produced by laser heating of hexagonal BN in a diamond anvil cell at a nitrogen pressure of 10.1 GPa. Most of these defects may be annealed in situ after just a few minutes of electron irradiation in a 300 kV electron microscope (electron dose of 10–20 A/cm2), while almost complete ordering of the nanotubular shells occurs. These results imply that there is not sufficient time for annealing-out of defects during BN nanotube formation.