Abstract
Structure and electronic properties of carbon nanotubes
(CNTs) with grain boundaries (GBs) are investigated using
density-functional calculations, where the GBs parallel and perpendicular
to the tube axis are considered. Simulation results show that
the GBs have a great effect on the electronic properties of the CNTs.
For the GBs along the tube axis, the CNTs are narrow or zero band
gap (<0.16 eV) materials, independent of the misoritentaion angle
and diameter. For the GBs perpendicular to the tube axis, localized
electronic states appear within the GBs regions, leading to a larger
band gap of up to 0.6 eV. It is convenient to transport and localize the
electrons and holes by engineering the GBs. These findings are of
great significance for developing carbon-based nanomaterials and
electronic devices.