C₆₀-Nanowire Two-State Resistance Switching Based on Fullerene Polymerization/Depolymerization

Fullerene has been expected to realize next generation nanoelectronics as a key element. However, although single-fullerene switch operation using scanning tunneling microscope (STM) has been developed, the structural architecture with electrodes is still needed to make progress as devices. Because the fullerenes are smaller than 1.0 nm, which is suitable for the STM approach, the subnanometer size is still too small, even with the latest device electrode fabrication techniques. Here we present the principle experiment on a self-assembling fullerene nanowire to drive single-fullerene switch. A fullerene C60-nanowire (C60NW), which was synthesized at a liquid-liquid interface, exhibited negative differential resistance (NDR) and two-state resistance switching generated by local polymerization and depolymerization among the C60 molecules. A C60NW was electrically characterized after a preset treatment to induce C60NW conductivity by electron-beam (EB) irradiation to form an initial conduction path. A current though the C60NW increased more than 100-fold after the preset treatment, whereas an as-grown C60NW exhibited a nanoampere-level current under a 20 V bias voltage. The current-voltage characteristics showed a nonlinear current increase and NDR, leading to reproducible two-state resistance switching under bias-voltage modulation. The nonlinear current increase, the NDR, and the resistance switching are explained by local energy control of the current-induced connection and disconnection of C60 molecules, leading to tunneling current modulation toward a single element of C60 in a nanomaterial switching function.