Applied Physics A

, Volume 74, Issue 3, pp 355–361

N-doping and coalescence of carbon nanotubes: synthesis and electronic properties

  • M. Terrones
  • P.M. Ajayan
  • F. Banhart
  • X. Blase
  • D.L. Carroll
  • J.C. Charlier
  • R. Czerw
  • B. Foley
  • N. Grobert
  • R. Kamalakaran
  • P. Kohler-Redlich
  • M. Rühle
  • T. Seeger
  • H. Terrones

DOI: 10.1007/s003390201278

Cite this article as:
Terrones, M., Ajayan, P., Banhart, F. et al. Appl Phys A (2002) 74: 355. doi:10.1007/s003390201278

Abstract.

Self-assembly pyrolytic routes to large arrays (<2.5 cm2) of aligned CNx nanotubes (15–80 nm OD and <100 μm in length) are presented. The method involves the thermolysis of ferrocene/melamine mixtures (5:95) at 900–1000 °C in the presence of Ar. Electron energy loss spectroscopy (EELS) reveals that the N content varies from 2–10%, and can be bonded to C in two different fashions (double-bonded and triple-bonded nitrogen). The electronic densities of states (DOS) of these CNx nanotubes, using scanning tunneling spectroscopy (STS), are presented. The doped nanotubes exhibit strong features in the conduction band close to the Fermi level (0.18 eV). Using tight-binding and ab initio calculations, we confirm that pyridine-like (double-bonded) N is responsible for introducing donor states close to the Fermi Level. These electron-rich structures are the first example of n-type nanotubes. Finally, it will be shown that moderate electron irradiation at 700–800 °C is capable of coalescing single-walled nanotubes (SWNTs). The process has also been studied using tight-binding molecular dynamics (TBMD). Vacancies induce the coalescence via a zipper-like mechanism, which has also been observed experimentally. These vacancies trigger the organization of atoms on the tube lattices within adjacent tubes. These results pave the way to the fabrication of nanotube heterojunctions, robust composites, contacts, nanocircuits and strong 3D composites using N-doped tubes as well as SWNTs.

PACS: 61.48.+c; 61.46.+w; 73.22.-f

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • M. Terrones
    • 1
  • P.M. Ajayan
    • 3
  • F. Banhart
    • 4
  • X. Blase
    • 5
  • D.L. Carroll
    • 6
  • J.C. Charlier
    • 7
  • R. Czerw
    • 6
  • B. Foley
    • 6
  • N. Grobert
    • 1
  • R. Kamalakaran
    • 9
  • P. Kohler-Redlich
    • 9
  • M. Rühle
    • 9
  • T. Seeger
    • 9
  • H. Terrones
    • 2
  1. 1.Fullerene Science Centre, University of Sussex, Brighton BN1 9QJ, UKUK
  2. 2.IPICyT, Venustiano Carranza 2425-A, Col. Los Filtros, 78210 San Luis Potosí, SLP. MéxicoMX
  3. 3.Department of Materials Science & Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USAUS
  4. 4.Z.E. Elektronenmikroskopie, Universität Ulm, 89069 Ulm, GermanyDE
  5. 5.Département de Physique des Matériaux, Université Claude Bernard, 69622 Villeurbanne, FranceFR
  6. 6.Department of Physics and Astronomy, Clemson University, Clemson SC 29634, USAUS
  7. 7.Unit of Physics of Materials (PCPM), University of Louvain, 1348 Louvain-la-Neuve, BelgiumBE
  8. 8.Department of Physics, Trinity College Dublin, Dublin 2, IrelandIE
  9. 9.Max Planck Institut für Metallforschung, Seestrasse 92, 70174 Stuttgart, GermanyDE