Raman studies of single-walled carbon nanotubes synthesized by pulsed laser ablation at room temperature

In this article, single-walled carbon nanotubes (SWCNTs) are synthesized at room temperature using pulsed laser ablation of ferrocene mixed graphitic target. Radial breathing mode (RBM) reveals the presence of semiconducting SWCNTs of multiple diameters. Quantum confinement model is developed for Raman line-shape of G (-) feature. It is invoked here that G-feature is the manifestation of TO phonons in the semiconducting SWCNTs. Disorder in the SWCNTs is studied here as a function of the concentration of ferrocene in the graphitic target using X-ray diffraction analysis, oscillator strength of G (-) feature and D mode and Raman line-shape model of G (-) feature. Furthermore, phonon softening of G (-) feature of semiconducting SWCNTs is observed as a function of the diameter of nanotube.