Controlled Hysteresis of Conductance in Molecular Tunneling Junctions

Junwoo Park, Mohamad S. Kodaimati, Lee Belding, Samuel E. Root, George C. Schatz, George M. Whitesides*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


The problem this paper addresses is the origin of the hysteretic behavior in two-terminal molecular junctions made from an EGaIn electrode and self-assembled monolayers of alkanethiolates terminated in chelates (transition metal dichlorides complexed with 2,2′-bipyridine; BIPY-MCl2). The hysteresis of conductance displayed by these BIPY-MCl2junctions changes in magnitude depending on the identity of the metal ion (M) and the window of the applied voltage across the junction. The hysteretic behavior of conductance in these junctions appears only in an incoherent (Fowler-Nordheim) tunneling regime. When the complexed metal ion is Mn(II), Fe(II), Co(II), or Ni(II), both incoherent tunneling and hysteresis are observed for a voltage range between +1.0 V and -1.0 V. When the metal ion is Cr(II) or Cu(II), however, only resonant (one-step) tunneling is observed, and the junctions exhibit no hysteresis and do not enter the incoherent tunneling regime. Using this correlation, the conductance characteristics of BIPY-MCl2junctions can be controlled. This voltage-induced change of conductance demonstrates a simple, fast, and reversible way (i.e., by changing the applied voltage) to modulate conductance in molecular tunneling junctions.

Original languageEnglish (US)
Pages (from-to)4206-4216
Number of pages11
JournalACS nano
Issue number3
StatePublished - Mar 22 2022


  • EGaIn junction
  • charge transport
  • hysteresis in conductance
  • molecular electronics
  • molecular tunneling junctions
  • quantum tunneling
  • self-assembled monolayers (SAMs)

ASJC Scopus subject areas

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


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