Scaling of exciton binding energy with external dielectric function in carbon nanotubes

Andrew G. Walsh, A. Nickolas Vamivakas, Yan Yin, Stephen B. Cronin, M. Selim Ünlü, Bennett B. Goldberg, Anna K. Swan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


We develop a scaling relationship between the exciton binding energy and the external dielectric function in carbon nanotubes. We show that the electron-electron and electron-hole interaction energies are strongly affected by screening yet largely counteract each other, resulting in much smaller changes in the optical transition energy. The model indicates that the relevant particle interaction energies are reduced by as much as 50% upon screening by water and that the unscreened electron-electron interaction energy is larger than the unscreened electron-hole interaction energy, in agreement with explanations of the "ratio problem." We apply the model to measurements of the changes in the optical transition energies in single, suspended carbon nanotubes as the external dielectric environment is altered.

Original languageEnglish (US)
Pages (from-to)2375-2379
Number of pages5
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Issue number7
StatePublished - May 2008


  • Carbon nanotubes
  • Dielectric
  • Excitons
  • Screening

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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