Temperature dependence of the optical excitation lifetime and band gap in chirality assigned semiconducting single-wall carbon nanotubes

Abstract

The temperature dependence of optical excitation lifetime $1∕\ensuremath{\Gamma}$ and transition energies ${E}_{ii}$ were measured for bucky papers of single-wall carbon nanotubes (SWCNTs) and inner tubes in double-wall carbon nanotubes (DWCNTs) using resonant Raman scattering on the radial breathing mode. The temperature dependence of $\ensuremath{\Gamma}$ and ${E}_{ii}$ is the same for both types of samples and is independent of tube chirality. The data suggest that electron-phonon interaction is responsible for the temperature dependence of ${E}_{ii}$ and $\ensuremath{\Gamma}$. The temperature independent contribution to $\ensuremath{\Gamma}$ is much larger in SWCNT than in DWCNT samples. This is explained by the different nanotube environment in the two types of samples. $\ensuremath{\Gamma}$ for the inner tubes of the DWCNTs is only $\ensuremath{\sim}30\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ below $150\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, which is comparable to that found for individual SWCNTs and is considered as intrinsic to the tubes.