Chiral Index Dependence of the G+ and G鈥?/sup> Raman Modes in Semiconducting Carbon Nanotubes

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• 作者：Hagen Telg ; Juan G. Duque ; Matthias Staiger ; Xiaomin Tu ; Frank Hennrich ; Manfred M. Kappes ; Ming Zheng ; Janina Maultzsch ; Christian Thomsen ; Stephen K. Doorn
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：January 24, 2012
• 年：2012
• 卷：6
• 期：1
• 页码：904-911
• 全文大小：519K
• 年卷期：v.6,no.1(January 24, 2012)
• ISSN：1936-086X

文摘

Raman spectroscopy on the radial breathing mode is a common tool to determine the diameter d or chiral indices (n,m) of single-wall carbon nanotubes. In this work we present an alternative technique to determine d and (n,m) based on the high-energy G鈥?/sup> mode. From resonant Raman scattering experiments on 14 highly purified single chirality (n,m) samples we obtain the diameter, chiral angle, and family dependence of the G鈥?/sup> and G⁺ peak position. Considering theoretical predictions we discuss the origin of these dependences with respect to rehybridization of the carbon orbitals, confinement, and electron鈥揺lectron interactions. The relative Raman intensities of the two peaks have a systematic chiral angle dependence in agreement with theories considering the symmetry of nanotubes and the associated phonons.

Keywords:

single-wall carbon nanotubes; Raman spectroscopy; G mode; LO/TO phonons; diameter determination; (n,m) assignment