Structure Of Double-walled Carbon Nanotubes Research Articles

X-ray photoelectron spectroscopy studies of double-walled carbon nanotube bundles synthesized using thermal chemical vapor deposition

We investigated the electronic structure of double-walled carbon nanotube (DWNT) bundles by variable-energy X-ray photoelectron spectroscopy (XPS). High-purity DWNT bundles were synthesized using MgO-supported Co–Mo catalysts by chemical vapor deposition of CH 4. As the photon energy of XPS increases from 360 to 1265 eV, the width of C 1s peaks becomes broader, probably due to the van der Waals interaction between the nanotubes in bundles. The XPS valence band analysis suggests that the present DWNT bundles would have more delocalized graphite-π electrons than the multiwalled nanotubes.

Curvature-induced metallization of double-walled semiconducting zigzag carbon nanotubes.

We report total-energy electronic-structure calculations that provide energetics and electronic structures of double-walled carbon nanotubes consisting of semiconducting (n,0) nanotubes. We find that optimum spacing between the walls of the nanotubes is slightly larger than the interlayer spacing of the graphite. We also find that the electronic structures of the double-walled nanotubes with the inner (7,0) nanotube are metallic with multicarrier characters in which electrons and holes exist on inner and outer nanotubes, respectively. Interwall spacing and curvature difference are found to be essential for the electron states around the Fermi level.

Investigation of the fabrication and structure of double-wall carbon nanotubes

Using the composite graphite rods with the sulphide of iron group metals as anode, the double-wall carbon nanotubes have been fabricated by arc discharging under hydrogen atmosphere. By means of transmission electron microscope, it was found that the double-wall carbon nanotubes were formed in the inner-walls of the evaporation chamber and around the cathode.