Complex branching phenomena in the growth of carbon nanotubes

We report here the experimental observation of complex branching phenomena in the growth of carbon nanotubes produced under specific arc-discharge conditions. High-resolution transmission electron microscopy (HRTEM) images demonstrate that two or three carbon nanotubes can join together under specific angles in L, Y, and T patterns with saddle surfaces at the junction. Adding to the observation of negative curvature surface in straight-line tubes that change their diameters, we report here negative curved areas that support the topography of a branching structure.