Controlling the tunnel resistance of suspended Ni nanogaps using field-emission-induced electromigration

Abstract

The authors report on the ability to control the tunnel resistance of suspended Ni nanogaps by field-emission-induced electromigration. This method is called “activation.” Suspended Ni nanogaps are ideal for investigating activation because the leakage currents flowing through the substrates are suppressed in these structures. The tips of suspended Ni nanogap electrodes are isolated from the SiO2 substrates, so it is expected that the suspended Ni nanogaps act as isolated tunnel junctions during activation. After undergoing activation, the suspended Ni nanogaps clearly exhibited tunneling I–V properties. Furthermore, the authors were able to tune the tunnel resistance of the suspended Ni nanogaps using the activation method. When the applied voltage was swept, the device current switched between high- and low-resistance states. The results imply that activation is a viable method for modulating the electrical properties of suspended Ni nanogaps at the nanometer scale.