Replacing AgTSSCH2-R with AgTSO2C-R in EGaIn-Based Tunneling Junctions Does Not Significantly Change Rates of Charge Transport

This paper compares rates of charge transport by tunneling across junctions with the structures AgTSX(CH2)2nCH3 //Ga2O3 /EGaIn (n=1–8 and X= SCH2 and O2C); here AgTS is template‐stripped silver, and EGaIn is the eutectic alloy of gallium and indium. Its objective was to compare the tunneling decay coefficient (β, Å−1) and the injection current (J0, A cm−2) of the junctions comprising SAMs of n‐alkanethiolates and n‐alkanoates. Replacing AgTSSCH2‐R with AgTSO2C‐R (R=alkyl chains) had no significant influence on J0 (ca. 3×103 A cm−2) or β (0.75–0.79 Å−1)—an indication that such changes (both structural and electronic) in the AgTSXR interface do not influence the rate of charge transport. A comparison of junctions comprising oligo(phenylene)carboxylates and n‐alkanoates showed, as expected, that β for aliphatic (0.79 Å−1) and aromatic (0.60 Å−1) SAMs differed significantly. Either way: For junctions comprising thiolate‐ and carboxylate‐anchored self‐assembled monolayers (SAMs) the role of the metal–SAM interface in charge transport by tunneling was investigated and the charge‐transport rates were measured. The data suggest that Ag–SAM interfaces having either a thiolate or carboxylate anchoring group may be directly comparable.