Comparison of SAM-Based Junctions with Ga2O3/EGaIn Top Electrodes to Other Large-Area Tunneling Junctions

This paper compares the J(V) characteristics obtained for self-assembled monolayer (SAM)-based tunneling junctions with top electrodes of the liquid eutectic of gallium and indium (EGaIn) fabricated using two different procedures: (i) stabilizing the EGaIn electrode in PDMS microchannels and (ii) suspending the EGaIn electrode from the tip of a syringe. These two geometries of the EGaIn electrode (with, at least when in contact with air, its solid Ga2O3 surface film) produce indistinguishable data. The junctions incorporated SAMs of SCn–1CH3 (with n = 12, 14, 16, or 18) supported on ultraflat, template-stripped silver electrodes. Both methods generated high yields of junctions (70–85%) that were stable enough to conduct measurements of J(V) with statistically large numbers of data (N = 400–1000). The devices with the top electrode stabilized in microchannels also made it possible to conduct measurements of J(V) as a function of temperature, almost down to liquid nitrogen temperatures (T = 110–293 K). The ...