Confinement of excitons for the lowest optical transition energies of single wall carbon nanotubes

Ahmad R.T. Nugraha, Kentaro Sato, Riichiro Saito

Research output: Contribution to journalArticlepeer-review


The confinement of excitons in a single wall carbon nanotube (SWNT) is discussed based on an analysis of the environmental effect on the optical transition energies, Eii, measured by photoluminescence spectroscopy. We use the effective dielectric constant κ as a function of nanotube diameter and exciton size that has also been used to reproduce excitonic transition energies Eii from resonance Raman spectroscopy experiments. When we focus our attention to the lowest transitions, E 11 region, we find a systematic deviation of the κ values for semiconducting type-I and type-II carbon nanotubes. We suggest that the E 11 energies observed by photoluminescence are upshifted to the calculated E11 energies due to the confinement of excitons in the SWNTs. Considering this effect, the same energy shift formula for the environmental effect as that for the the Raman spectroscopy results can be used to reproduce experimental Eii values from photoluminescence spectroscopy within a good accuracy, hence providing an accurate assignment of many nanotube chiralities.

Original languageEnglish
Pages (from-to)367-371
Number of pages5
Journale-Journal of Surface Science and Nanotechnology
Publication statusPublished - 2010 Nov 6


  • Carbon nanotubes
  • Light scattering
  • Many body and quasi-particle theories

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Condensed Matter Physics
  • Mechanics of Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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