Raman Spectroscopy Investigation of Laser-Irradiated Single-Walled Carbon Nanotube Films

Raman spectroscopy (RS) is the tool of choice for the analysis of carbon nanomaterials. In graphene and carbon nanotubes (CNT), RS provides rich information such as defect concentration, CNT chirality, graphene layer number, doping, strain, and other physical parameters of interest. This work presents the RS investigation of a semiconducting CNT film after high power laser irradiation. Changes were observed in the D band revealing the change in the defect concentration induced by the laser. More importantly, it was found the relative intensity decrease of G(-) and some radial breathing modes which suggests that the effects of laser irradiation induce diameter-selective effects in CNTs. The spectroscopic changes to the selective electronic structure modification for some semiconducting CNTs were attributed as due to those CNTs getting closer to resonance conditions with the fixed laser excitation.