Polarized Raman Study of Single-Wall Semiconducting Carbon Nanotubes

Abstract

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: $1549{\mathrm{cm}}^{\ensuremath{-}1}$ $[{E}_{2}({E}_{2g})]$, $1567{\mathrm{cm}}^{\ensuremath{-}1}$ $[A({A}_{1g}){+E}_{1}({E}_{1g})]$, $1590{\mathrm{cm}}^{\ensuremath{-}1}$ $[A({A}_{1g}){+E}_{1}({E}_{1g})]$ and $1607{\mathrm{cm}}^{\ensuremath{-}1}$ $[{E}_{2}({E}_{2g})]$. The frequency shifts of the tangential $G$ modes from the $2D$ graphitelike ${E}_{{2g}_{2}}$ frequency are discussed in terms of the nanotube geometry.