Abstract Submitted to the NANOTUBE'05 Conference:

Carbon nanotubes (CNTs) have remarkable optical and transport properties, with important implications for technology. They have extraordinarily high electron and hole mobilities at low fields, although the mobility saturates at high fields. We calculate the electron-phonon scattering and binding in CNTs, within a tight binding model, and calculate mobility using a multi-band Boltzmann treatment [1]. Our results for mobility as a function of temperature, electric field, and nanotube chirality can be captured by a few simple equations, to provide a broad overview of the transport. The optical properties are also unusual, being dominated by excitons even at room temperature, with binding energies and oscillator strengths that are orders of magnitude larger than those in conventional semiconductors. We find simple scaling relationships for the exciton size, oscillator strength, and binding energy as a function the tube radius, chirality, and the dielectric constant of the embedding material [2]. For the optical absorption, we find a phonon sideband 200 meV about the zero-phonon line, which provides a signature of the excitonic character [3]. Finally, we calculate the exciton radiative lifetime, which in turn determines the efficiency. We predict an unusual nonmonotonic temperature dependence, due to optically inactive exciton bands below the optically active exciton.

References
[1] V. Perebeinos, J. Tersoff, and Ph. Avouris, Phys. Rev. Lett. 94, 086802 (2005).
[2] V. Perebeinos, J. Tersoff, and Ph. Avouris, Phys. Rev. Lett. 92, 257402 (2004).
[3] V. Perebeinos, J. Tersoff, and Ph. Avouris, Phys. Rev. Lett. 94, 027402 (2005).

 

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