Properties of single-wall carbon nanotubes

Measurements are reported of the Raman spectra (including the second order spectrum), the diffuse reflectance (for photon energies 0.5 - 5 eV), and de conductivity of purified single-wall carbon nanotube (SWCN) pellets made u sing the catalytic are discharge method. The Raman data indicate a strong p resence of SWCNs of diameter 1.22 nm. The diffuse reflectance shows a sharp increase above 4 eV, and a gradual increase below 3 eV down to the limit o f measurements at 0.5 eV. Metallic conduction is indicated by the observati on that the de conductivity does not extrapolate to zero at zero temperatur e. The temperature dependence of conductivity, which remains nonmetallic in sign up to 300 K, is consistent with tunnelling through thin barriers betw een metallic regions.