title: Intensity Ratio of Resonant Raman Modes for (n,m) Enriched Semiconducting Carbon Nanotubes.
abstract: Relative intensities of resonant Raman spectral features, specifically the radial breathing mode (RBM) and G modes, of 11, chirality-enriched, single-wall carbon nanotube (SWCNT) species were established under second-order optical transition excitation. The results demonstrate an under-recognized complexity in the evaluation of Raman spectra for the assignment of (n,m) population distributions. Strong chiral angle and mod dependencies affect the intensity ratio of the RBM to G modes and can result in misleading interpretations. Furthermore, we report five additional (n,m) values for the chirality-dependent G(+) and G(-) Raman peak positions and intensity ratios; thereby extending the available data to cover more of the smaller diameter regime by including the (5,4) second-order, resonance Raman spectra. Together, the Raman spectral library is demonstrated to be sufficient for decoupling G peaks from multiple species via a spectral fitting process, and enables fundamental characterization even in mixed chiral population samples.
authors.affiliation: Physical Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Piao
authors.affiliation: Physical Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.|Department of Physics, Astronomy and Geosciences, Towson University Towson, Maryland 20899, United States.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Simpson
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology Gaithersburg, Maryland 20899, United States.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Streit
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology Gaithersburg, Maryland 20899, United States.
authors.forename: Geyou
authors.initials: G
authors.lastname: Ao
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology Gaithersburg, Maryland 20899, United States.
authors.forename: Ming
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Material Measurement Laboratory, National Institute of Standards and Technology Gaithersburg, Maryland 20899, United States.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Fagan
authors.affiliation: Physical Measurement Laboratory, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
authors.forename: Angela R
authors.initials: AR
authors.lastname: Hight Walker
keywords: Raman intensity ratio; aqueous two phase separation; chiral angle; resonance Raman; single-wall carbon nanotubes