Single-Electron Tunneling Effects in Electromigrated Coulomb Island Between Au Nanogaps

Over the past few decades several experimental methods have been used to fabricate single-electron transistors (SETs). We have reported the method for fabrication of the SETs using field-emission-induced electromigration, which is so-called "activation". By applying the activation to the nanogap electrodes, it is expected that the moved atoms accumulate within the gaps and play the dual role of reducing the gap width and forming Coulomb islands. We applied the activation procedure to the Au nanogaps at room temperature under vacuum. Following the activation, drain current I-D-drain voltage V-D characteristics of the devices were obtained with the modulation of gate voltage V-G at T= 18 K. As a result, I-D-V-D characteristics displayed Coulomb blockade properties, and the Coulomb blockade voltage was clearly modulated by gate voltage V-G. These results indicate that this simple technique can make Au nanogap-based SETs easier.