Departmental Papers (MSE)

Document Type

Journal Article

Date of this Version

January 2004

Comments

Postprint version. Published in Journal of Applied Physics, Volume 95, Issue 2, January 15, 2004, pages 649-655.
Publisher URL: http://dx.doi.org/10.1063/1.1627457

Abstract

Fibers of single wall carbon nanotubes extruded from super-acid suspensions exhibit preferred orientation along their axes. We characterize the alignment by x-ray fiber diagrams and polarized Raman scattering, using a model which allows for a completely unaligned fraction. This fraction ranges from 0.17 to 0.05±0.02 for three fibers extruded under different conditions, with corresponding Gaussian full widths at half-maximum (FWHM) from 64o to 44o±2o. FWHM, aligned fraction, electrical and thermal transport all improve with decreasing extrusion orifice diameter. Resistivity, thermoelectric power and resonant-enhanced Raman scattering indicate that the neat fibers are strongly p-doped; the lowest observed ρ is 0.25mΩcm at 300 K. High temperature annealing increases ρ by more than 1 order of magnitude and restores the Raman resonance associated with low-energy van Hove transitions, without affecting the nanotube alignment.

Share

COinS

Date Posted: 21 January 2005

This document has been peer reviewed.