Probing the nature and resistance of the molecule-electrode contact in SAM-based junctions

C. S. Suchand Sangeeth, Albert Wan, Christian A. Nijhuis*

*Corresponding author for this work

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Abstract

It is challenging to quantify the contact resistance and to determine the nature of the molecule–electrode contacts in molecular two-terminal junctions. Here we show that potentiodynamic and temperature dependent impedance measurements give insights into the nature of the SAM–electrode interface and other bottlenecks of charge transport (the capacitance of the SAM (CSAM) and the resistance of the SAM (RSAM)), unlike DC methods, independently of each other. We found that the resistance of the top-electrode–SAM contact for junctions with the form of AgTS–SCn//GaOx/EGaIn with n = 10, 12, 14, 16 or 18 is bias and temperature independent and hence Ohmic (non-rectifying) in nature, and is orders of magnitude smaller than RSAM. The CSAM and RSAM are independent of the temperature, indicating that the mechanism of charge transport in these SAM-based junctions is coherent tunneling and the charge carrier trapping at the interfaces is negligible.
Original languageEnglish
Pages (from-to)12061-12067
JournalNanoscale
Volume7
Issue number28
DOIs
Publication statusPublished - 2015
Externally publishedYes

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