Dependence of Raman spectra G′ band intensity on metallicity of single-wall carbon nanotubes
Year: 2007
Type: article
Abstract: We report the peculiar behavior of the ${G}^{\ensuremath{'}}$ band Raman intensity, which is dependent on the metallicity of single-wall carbon nanotubes (SWCNTs). In the metallic SWCNTs, the ${G}^{\ensuremath{'}}$ band intensity was enhanced relative to the $G$ band intensity, while the ${G}^{\ensuremath{'}}$ band intensity was suppressed in the semiconducting SWCNTs. Resonance Raman spectroscopy (using laser energies of ${E}_{\mathit{\text{laser}}}=2.41$, 1.96, 1.58, and $1.165\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$) showed these features on the metal-enriched and semiconducting-enriched SWCNT samples that had been selectively separated by the nitronium ions. The metallicity dependence was explained theoretically by calculating the resonance Raman intensity within the extended tight-binding calculations. The calculated results confirm that the ${G}^{\ensuremath{'}}$ band intensity of the metallic SWCNTs is stronger than that for the semiconducting SWCNTs because the electron-phonon matrix elements for the TO phonon at the $K$ point is larger for metallic SWCNTs and the resonance window for ${E}_{33}^{S}$ is larger than that for ${E}_{11}^{M}$.
Source: Physical Review B
Institutions: Sungkyunkwan University, Tohoku University
Language: Latvian
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2074677017