Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Intensity Ratio of Resonant Raman Modes for (n,m) Enriched Semiconducting Carbon Nanotubes



Yanmei Piao, Jeffrey R. Simpson, Jason K. Streit, Geyou Ao, Ming Zheng, Angela R. Hight Walker


Relative intensities of resonant Raman spectral features, specifically the radial breathing mode (RBM) and G modes, of eleven chirality-enriched single-wall carbon nanotube (SWCNT) species were established under second-order optical transition excitation. The results demonstrate a significantly under-recognized complexity in the evaluation of Raman spectra for the assignment of (n,m) population distributions. The strong chiral angle and mod dependencies affect the intensity ratio of RBM to G band and can result in misleading interpretations. Additionally, we validate our results on chirality dependent G+ and G- positions, supporting accuracy in literature values for these peak positions and further extend the trend to the small diameter regime by including the first (5,4) second-order resonance Raman spectra. Together, the Raman spectra library is demonstrated to be sufficient for decoupling multiple species via a spectral fitting process, to enable fundamental characterization even in mixed chiral population samples.
ACS Nano


Resonance Raman, carbon nanotubes, Raman Intensity Ratio


Piao, Y. , Simpson, J. , Streit, J. , Ao, G. , Zheng, M. and Hight, A. (2016), Intensity Ratio of Resonant Raman Modes for (n,m) Enriched Semiconducting Carbon Nanotubes, ACS Nano, [online], (Accessed May 23, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created April 29, 2016, Updated November 10, 2018