Existence of an upper limit on the density of excitons in carbon nanotubes by diffusion-limited exciton-exciton annihilation: Experiment and theory

Yoichi Murakami and Junichiro Kono
Phys. Rev. B 80, 035432 – Published 29 July 2009

Abstract

Through an investigation of photoemission properties of highly photoexcited single-walled carbon nanotubes, we demonstrate that there is an upper limit on the achievable excitonic density. As the intensity of optical excitation increases, all photoluminescence emission peaks arising from different chirality single-walled carbon nanotubes showed clear saturation in intensity. Each peak exhibited a saturation value that was independent of the excitation wavelength, indicating that there is an upper limit on the excitonic density for each nanotube species. We propose that this saturation behavior is a result of efficient exciton-exciton annihilation through which excitons decay nonradiatively. In order to explain the experimental results and obtain excitonic densities in the saturation regime, we have developed a model, taking into account the generation, diffusion-limited exciton-exciton annihilation, and spontaneous decays of one-dimensional excitons. Using the model, we were able to reproduce the experimentally obtained saturation curves under certain approximations, from which the excitonic densities were estimated. The validity of the model was confirmed through comparison with Monte Carlo simulations. Finally, we show that the conventional rate equation for exciton-exciton annihilation fails to fit the experimentally observed saturation behavior, especially at high excitonic densities.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 1 January 2009

DOI:https://doi.org/10.1103/PhysRevB.80.035432

©2009 American Physical Society

Authors & Affiliations

Yoichi Murakami1,2,* and Junichiro Kono1

  • 1Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
  • 2Department of Chemical System Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan

  • *Corresponding author. Present address: Global Edge Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan; murakami.y.af@m.titech.ac.jp

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 80, Iss. 3 — 15 July 2009

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×