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Probing Charge Transport in Molecular Electronic Junctions With Transition Voltage Spectroscopy



J M. Beebe, BongSoo Kim, C D. Frisbie, James G. Kushmerick


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 not yet been 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, consistent with other spectroscopic measurements of the barrier height for alkyl junctions. We further show that 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.
Nature Nanotechnology


molecular electronics, nanotechnology


Beebe, J. , Kim, B. , Frisbie, C. and Kushmerick, J. (2008), Probing Charge Transport in Molecular Electronic Junctions With Transition Voltage Spectroscopy, Nature Nanotechnology (Accessed September 25, 2023)
Created October 16, 2008