Topological structure of Y-junction carbon nanotubes

Abstract

Y-junction carbon nanotubes (CNTs) grown by hot-filament chemical vapor deposition (HFCVD) method have been investigated by transmission electron microscopy (TEM). A fish-bone like feature has been observed on the tubes around the Y-junction. It is found that all the Y-junctions have a predominant branching angle ranging from 50–80°, roughly twice the reported bending angles of single bend junctions. A speculation of the topological structure of single-walled Y-junction CNTs has been made by adopting the feature. A simulated atomic model is found to interpret well the particularly angled Y-junction CNTs, where a total of six heptagons around the Y-junctions are required as topological defects to fit well with the hexagonal network.