Laser-induced graphitic healing of carbon nanotubes aligned in a sheet

A laser scanning method was developed to heal the graphitic defects of carbon nanotubes (CNTs). The laser beam was controlled to longitudinally scan CNTs aligned in the freestanding CNT sheets. The localized heating zone generated by the laser beam moved along the CNT axes and exhibited the extreme thermal conditions of fast-heating and fast-cooling. This unique laser-CNT interaction was beneficial to quickly heal the CNT defects and limited the undesired structural transformation of CNTs. The effectiveness of the introduced laser method in healing CNTs was confirmed by comparing with the conventional furnace annealing method and also verified by treating the plasma-bombarded CNTs. The generated localized heating zone and the scanning pattern controllability of the laser irradiation method are favorable to thermally treat the 1D-structured nanomaterials having the dominant longitudinal thermal conductivities such as CNTs or nanowires