# Charge Transport and Rectification in Arrays of SAM-Based Tunneling Junctions

 Title: Charge Transport and Rectification in Arrays of SAM-Based Tunneling Junctions Author: Nijhuis, Christian A.; Reus, William F.; Barber, Jabulani Randall; Dickey, Michael D.; Whitesides, George M. Note: Order does not necessarily reflect citation order of authors. Citation: Nijhuis, Christian A., William F. Reus, Jabulani R. Barber, Michael D. Dickey, and George M. Whitesides. 2010. Charge transport and rectification in arrays of SAM-based tunneling junctions. Nano Letters 10(9): 3611-3619. Full Text & Related Files: Nijhuis_ChargeTransport.pdf (8.961Mb; PDF) Abstract: This paper describes a method of fabrication that generates small arrays of tunneling junctions based on self-assembled monolayers (SAMs); these junctions have liquid-metal top-electrodes stabilized in microchannels and ultraflat (template-stripped) bottom-electrodes. The yield of junctions generated using this method is high (70−90%). The junctions examined incorporated SAMs of alkanethiolates having ferrocene termini (11-(ferrocenyl)-1-undecanethiol, SC$$_{11}$$Fc); these junctions rectify currents with large rectification ratios (R), the majority of which fall within the range of 90−180. These values are larger than expected (theory predicts R ≤ 20) and are larger than previous experimental measurements. SAMs of n-alkanethiolates without the Fc groups (SC$$_{n−1}$$CH$$_3$$, with n = 12, 14, 16, or 18) do not rectify (R ranged from 1.0 to 5.0). These arrays enable the measurement of the electrical characteristics of the junctions as a function of chemical structure, voltage, and temperature over the range of 110−293 K, with statistically large numbers of data (N = 300−800). The mechanism of rectification with Fc-terminated SAMs seems to be charge transport processes that change with the polarity of bias: from tunneling (at one bias) to hopping combined with tunneling (at the opposite bias). Published Version: doi:10.1021/nl101918m Other Sources: http://gmwgroup.harvard.edu/pubs/pdf/1093.pdf http://gmwgroup.unix.fas.harvard.edu/pubs/pdf/1093.pdf Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:9896817 Downloads of this work: