Making electrical contacts to molecular monolayers

X. D. Cui, X. Zarate, J. Tomfohr, O. F. Sankey, A. Primak, Ana L Moore, Thomas A Moore, John Devens Gust, G. Harris, S. M. Lindsay

Research output: Contribution to journalArticle

289 Citations (Scopus)


Electrical contacts between a metal probe and molecular monolayers have been characterized using conducting atomic force microscopy in an inert environment and in a voltage range that yields reversible current-voltage data. The current through alkanethiol monolayers depends on the contact force in a way that is accounted for by the change of chain-to-chain tunnelling with film thickness. The electronic decay constant, βN, was obtained from measurements as a function of chain length at constant force and bias, yielding βN = 0.8 ± 0.2 per methylene over a ± 3 V range. Current-voltage curves are difficult to reconcile with this almost constant value. Very different results are obtained when a gold tip contacts a 1, 8-octanedithiol film. Notably, the current-voltage curves are often independent of contact force. Thus the contact may play a critical role both in the nature of charge transport and the shape of the current-voltage curve.

Original languageEnglish
Pages (from-to)5-14
Number of pages10
Issue number1
Publication statusPublished - Feb 2002

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

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    Cui, X. D., Zarate, X., Tomfohr, J., Sankey, O. F., Primak, A., Moore, A. L., Moore, T. A., Gust, J. D., Harris, G., & Lindsay, S. M. (2002). Making electrical contacts to molecular monolayers. Nanotechnology, 13(1), 5-14.