Selective Etching of Thin Single-Walled Carbon Nanotubes

Raman spectroscopy and in situ Raman spectroelectrochemistry were applied to study the selective etching of thin tubes by lithium vapor in doped single-walled carbon nanotubes (SWCNTs). A strong doping of SWCNTs after the reaction with Li vapor was confirmed by the vanishing of the radial breathing mode (RBM) and by a strong attenuation of the tangential displacement (TG) band in the Raman spectra. The Raman spectra of the Li-vapor-treated SWCNTs after subsequent reaction with water showed changes in the diameter distribution compared with that of a pristine sample (nanotubes with diameters of