Elucidation of the origin of grown-in defects in carbon nanotubes

The origin of grown-in defects in carbon nanotubes (CNTs) is elucidated by in situ atomic-scale environmental transmission electron microscope (ETEM) observations of the chemical vapor deposition growth of CNTs. Our high-resolution ETEM observations clearly demonstrate that the deformation of nanoparticle catalysts (NPCs) during the growth of CNTs triggers the formation of various defects in CNTs. The small deformation of NPCs at the interface with CNTs gives rise to the formation of bends and disorder of the interlayer spacing in CNTs. The changes in the diameter and number of graphitic layers in CNTs are caused by the large protrusion on and shrink deformations of NPCs. This study provides insightful strategies to control the grown-in defects of CNTs.