Correlation between the saturation of emission current and defect co-ordination number for irradiated aligned multiwalled carbon nanotubes

► This letter establishes a correlation between the saturation of field emission current density and defect co-ordination number for low energy Ar+ ion irradiation of aligned multiwalled carbon nanotubes. ► Under high dose irradiation field emission current density, as obtained by in situ ion irradiation and field emission measurement decreases with the energy of the incident ion and finally saturates. ► Defect co-ordination number, calculated through Molecular Dynamics simulations increases for the low energy and finally saturates. ► Interestingly, the saturation in the emission current density and defect co-ordination number occurs at exactly same energy of Ar+ ions.