Resonance behavior of defect-induced modes in metallic and semiconducting single-walled carbon nanotubes



We analyze the defect-induced Raman mode (D mode) and the second order 2D mode of samples enriched with metallic and semiconducting single-walled carbon nanotube (SWCNT). By resonance Raman spectroscopy, we study the evolution of the line shape of the D and 2D mode. We compared the radial-breathing mode (RBM) frequencies with different components of the D and 2D mode in the enriched samples and a non-enriched SWCNT reference material. We show that the components of the broad D mode can be assigned to different species of nanotubes and that this assignment is not necessarily correlated to the RBM for the same excitation energy.

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Raman intensity of the 2D mode for differently enriched samples and comparison with a reference sample. The gray spectrum is the sum of the spectra from the enriched samples.