Local reconstruction and controllable nanospot welding of multiwalled carbon nanotubes under mild electron beam irradiation

Mild electron beam irradiation is proved to be an effective route to realize some nanoscale manipulation on the multiwalled carbon nanotubes (MWNTs) prepared by a simple CVD method, such as nanospot welding and controllable preparation of some special nanostructures (nanospindles and nanodumbbells). When being exposed to mild electron beam irradiation in a transmission electron microscope (TEM), MWNTs make apparent morphology and structural changes: the outer layers gradually deform and swell, and are transformed to amorphous carbon, while the inner layers keep the original tube-like morphologies. The deformation zones and the number of deformed layers in MWNTs can be precisely controlled by moving electron beam focal point and changing the irradiation period, and correspondingly, a controllable local reconstruction of an isolated MWNT and nanospot welding of some crossing or neighboring MWNTs can be realized in a TEM.