Structural measurements for single-wall carbon nanotubes by Raman scattering technique

Abstract The single-wall carbon nanotubes grown by different techniques have been investigated by Roman scattering and high resolution transmission electron microscopy (HRTEM). The tube diameter values and the tube distribution over diameter have been estimated from the position and shape of the low-frequency band in the Raman spectrum containing the ‘breathing” modes. The diameter-dependent enhancement of the Raman signals from the different nanotube fractions occurred not only due to optical resonance with the laser excitation energy, but also due to thermo-induced resonances. The low-field electron emission from the single-wall carbon nanotube material has been measured. The threshold fields were 0.75–2 V/μm, the emission current reached the value 15 mA/cm 2 at fields of 10 V/μm.