Strong enhancement of the Breit-Wigner-Fano Raman line in carbon nanotube bundles caused by plasmon band formation

We investigate the origin of the Breit-Wigner-Fano line in the Raman spectra of individual single-walled carbon nanotubes and their bundles. Using confocal Raman microscopy and atomic-force microscopy we found that the Breit-Wigner-Fano line intensity increases strongly with the bundle thickness. We confirmed this result by Raman investigations of partially decomposed bundles, which were additionally investigated by transmission electron microscopy. Our random-phase approximation based theory, which identifies the Breit-Wigner-Fano line as an excited band of plasmon-phonon modes, is fully consistent with the experimental results.

Electrical Transport and Confocal Raman Studies of Electrochemically Modified Individual Carbon Nanotubes

Raman investigation of single oxidized carbon nanotubes

The oxidation process of single-walled carbon nanotubes via nitric acid treatment was followed by IR-, UV-Vis-NIR, and single bundle Raman spectroscopy. The introduction of functional, oxygen-containing groups is revealed by an additional absorption band at 1725 cm−1, characteristic of carbonyl stretch vibrations. No significant shift of the optical absorption bands could be detected after oxidation. The combination of atomic force microscopy and confocal scanning resonance-enhanced Raman microscopy was used to investigate thin bundles and, eventually, individual nanotubes in detail. These experiments enabled determination of the dependence of the Raman intensity of the G-line (around 1590 …

Raman Imaging of Single Carbon Nanotubes

[19] The single crystals of the Bu4NBr0.6I1.4Cl salt, were obtained by addition of IBr to a solution of Bu4NCl in ethanol at a reagent ratio of 1:0.5. Stoichiometry of the anion has been found by EDX. Based on a Raman study the anion consists of the I2Br ‐ (band at 140 cm ‐1 ), IBr2 ‐ (band at 150‐ 176 cm ‐1 ), BrICl ‐ (band at 225 cm ‐1 ), and ICl2 ‐ (band at 250‐263 cm ‐1 ) trihalide anions. [20] The X-ray diffraction data from single crystals for both trihalide salts were measured using an Enraf Nonius CAD4 diffractometer with graphite monochromatic Mo Ka radiation (k = 0.71073 a) at room temperature. Unit cell parameters of the new a¢¢¢- crystal were determined from a leastsquares analy…