Effect of electron irradiation on the formation and healing of defects in carbon nanotubes

The effect of electron irradiation with E = 2 MeV and a dose of 1.9 × 1017 el/cm2 of annealed and pristine carbon nanotubes (CNTs) on the electrical conductivity σ(ρ), thermoelectric emf (α), and elastic characteristics during deformation and relaxation during unloading is studied. The annealing of CNTs at 800°C removes the topological defects (the Stone–Wales ones, vacancies, and adatoms) which distort the CNT shape. As is found, after electron irradiation with small doses (0.63 × 1017 el/cm2), the defects accumulate, while at high doses (1.9 × 1017 el/cm2) they are healed. The growth and radiation defects lead separately to a topological disorder, reducing the σ(ρ) parameter and increasing α. However, upon irradiation and during the interaction between the defects of different genesis, their healing becomes more effective in comparison with annealing, and the mechanism of effective healing can be associated with the small CNT sizes, rapid migration of the sputtered atoms between the graphene layers, and their recombination with vacancies.