| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Nanomaterials | Tuesday Sessions |
| Session NM-TuM |
| Session: | Nanofabrication and Nanodevices |
| Presenter: | Keita Sakai, Tokyo University of Agriculture & Technology, Japan |
| Authors: | K. Sakai, Tokyo University of Agriculture & Technology, Japan K. Minami, Tokyo University of Agriculture & Technology, Japan S. Tani, Tokyo University of Agriculture & Technology, Japan T. Sato, Tokyo University of Agriculture & Technology, Japan M. Ito, Tokyo University of Agriculture & Technology, Japan M. Yagi, National Institute of Technology, Ichinoseki College, Japan J. Shirakashi, Tokyo University of Agriculture & Technology, Japan |
| Correspondent: | Click to Email |
For many years, neuromorphic devices that can mimic functions of biological brains have been studied in the field of neuromorphic engineering. The synaptic functionality of neuromorphic hardwares originates in a gradually modified resistance. Previously, we have investigated simple methods for controlling the tunnel resistance of the nanogaps called activation. In this technique, electromigration is induced between nanogap electrodes by a field emission current, resulting in the reduction of the gap width. The tunnel resistance of the nanogaps also decreases after activation. In this study, we apply the activation procedure for Au nanogaps and demonstrate the experimental implementation of synaptic functions in Au nanogaps. First, Au nanogaps were fabricated by electron-beam lithography and lift-off process. Then, a fixed width and height voltage pulse was loaded to Au nanogaps periodically. After the applied pulse was removed, current decayed rapidly at the beginning of the time followed by a gradual fading to a stable level. By increasing the number of stimulations, the relaxation time increased, implying a slow fade in forgetting process time. Meanwhile, it was observed that current level was clearly elevated, showing a potentiation of synaptic weight. These phenomena confirm the STP-to-LTP transition in our device. These results indicate that inorganic synapses are successfully achieved using Au nanogaps controlled by the activation.