Introducing ionic and/or hydrogen bonds into the SAM//Ga2O 3 top-interface of AgTS/S(CH2) nT//Ga2O3/EGaIn junctions

Carleen M. Bowers, Kung Ching Liao, Hyo Jae Yoon, Dmitrij Rappoport, Mostafa Baghbanzadeh, Felice C. Simeone, George M. Whitesides

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)


Junctions with the structure AgTS/S(CH2) nT//Ga2O3/EGaIn (where S(CH2) nT is a self-assembled monolayer, SAM, of n-alkanethiolate bearing a terminal functional group T) make it possible to examine the response of rates of charge transport by tunneling to changes in the strength of the interaction between T and Ga2O3. Introducing a series of Lewis acidic/basic functional groups (T = -OH, -SH, -CO2H, -CONH 2, and -PO3H) at the terminus of the SAM gave values for the tunneling current density, J(V) in A/cm2, that were indistinguishable (i.e., differed by less than a factor of 3) from the values observed with n-alkanethiolates of equivalent length. The insensitivity of the rate of tunneling to changes in the terminal functional group implies that replacing weak van der Waals contact interactions with stronger hydrogen- or ionic bonds at the T//Ga2O3 interface does not change the shape (i.e., the height or width) of the tunneling barrier enough to affect rates of charge transport. A comparison of the injection current, J0, for T = -CO2H, and T = -CH2CH3-two groups having similar extended lengths (in Å, or in numbers of non-hydrogen atoms)-suggests that both groups make indistinguishable contributions to the height of the tunneling barrier.

Original languageEnglish
Pages (from-to)3521-3526
Number of pages6
JournalNano Letters
Issue number6
Publication statusPublished - 2014 Jun 11
Externally publishedYes


  • EGaIn
  • Tunneling
  • charge transport
  • interfaces
  • molecular electronics
  • self-assembled monolayers

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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