Replacing \(Ag ^{TS} SCH_2-R\) with \(Ag^{TS}O_2C-R\) in EGaIn-Based Tunneling Junctions Does Not Significantly Change Rates of Charge Transport

Abstract

This paper compares rates of charge transport by tunneling across junctions with the structures (Ag^{TS}X(CH_2)_{2n}CH_3 //Ga_2O_3 /EGaIn \space) (n=1–8 and (X= -SCH_2-) and (O_2C-)); here (Ag^{TS}) is template-stripped silver, and EGaIn is the eutectic alloy of gallium and indium. Its objective was to compare the tunneling decay coefficient ((\beta), Å(^{−1})) and the injection current ((J_0), A cm(^{−2})) of the junctions comprising SAMs of n-alkanethiolates and n-alkanoates. Replacing (Ag^{TS}SCH_2-R) with (Ag^{TS}O_2C-R) (R=alkyl chains) had no significant influence on (J_0) (ca. (3\times10^3 A cm^{−2})) or (\beta) (0.75–0.79 Å(^{−1}))—an indication that such changes (both structural and electronic) in the (Ag^{TS}XR) interface do not influence the rate of charge transport. A comparison of junctions comprising oligo(phenylene)carboxylates and n-alkanoates showed, as expected, that (\beta) for aliphatic (0.79 Å(^{−1})) and aromatic (0.60 Å(^{−1})) SAMs differed significantly.