Polarized Raman Study of Single-Wall Semiconducting Carbon Nanotubes

Polarized Raman spectra were obtained from a rope of aligned semiconducting single-wall nanotubes (SWNTs) in the vicinity of the $D$ band and the $G$ band. Based on group theory analysis and related theoretical predictions, the $G$-band profile was deconvolved into four intrinsic SWNT components with the following symmetry assignments: $1549{\mathrm{cm}}^{-1\mathrm{}}$ $\left[E_2\right(E_{2g}\left)\right]$, $1567{\mathrm{cm}}^{-1\mathrm{}}$ $\left[A\right(A_{1g}\left){+E}_1\right(E_{1g}\left)\right]$, $1590{\mathrm{cm}}^{-1\mathrm{}}$ $\left[A\right(A_{1g}\left){+E}_1\right(E_{1g}\left)\right]$ and $1607{\mathrm{cm}}^{-1\mathrm{}}$ $\left[E_2\right(E_{2g}\left)\right]$. The frequency shifts of the tangential $G$ modes from the $2D$ graphitelike $E_{{2g}_2}$ frequency are discussed in terms of the nanotube geometry.