Measuring relative barrier heights in molecular electronic junctions with transition voltage spectroscopy

Jeremy M. Beebe, Bong Soo Kim, C. Daniel Frisbei, James G. Kushmerick

Research output: Contribution to journalArticlepeer-review

261 Scopus citations

Abstract

Though molecular devices exhibiting potentially useful electrical behavior have been demonstrated, a deep understanding of the factors that influence charge transport in molecular electronic junctions has yet to be fully realized. Recent work has shown that a mechanistic transition occurs from direct tunneling to field emission in molecular electronic devices. The magnitude of the voltage required to enact this transition is molecule-specific, and thus measurement of the transition voltage constitutes a form of spectroscopy. Here we determine that the transition voltage for a series of alkanethiol molecules is invariant with molecular length, while the transition voltage of a conjugated molecule depends directly on the manner in which the conjugation pathway has been extended. Finally, by examining the transition voltage as a function of contact metal, we show that this technique can be used to determine the dominant charge carrier for a given molecular junction.

Original languageEnglish (US)
Pages (from-to)827-832
Number of pages6
JournalACS nano
Volume2
Issue number5
DOIs
StatePublished - May 2008

Keywords

  • Charge transport
  • Molecular electronics
  • Transition voltage spectroscopy
  • Tunneling

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