| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Wednesday Sessions |
| Session TF-WeP |
| Session: | Thin Films Poster Session II |
| Presenter: | Koji Minami, Tokyo University of Agriculture & Technology, Japan |
| Authors: | K. Minami, Tokyo University of Agriculture & Technology, Japan S. Tani, Tokyo University of Agriculture & Technology, Japan K. Sakai, 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 |
We developed a simple and controllable nanogap fabrication method called “activation.” This method is based on electromigration induced by Fowler-Nordheim (F-N) field emission current passing through the nanogaps. The F-N field emission current plays an important role in triggering the migration of atoms. By performing the activation, gap separations and tunnel resistances of the nanogaps are reduced because of the activated atoms that accumulated at the tips of nanogap electrodes. In this method, by only adjusting the applied current, we are able to control the structural properties of the nanogaps [1]. Previously, simultaneous tuning of the structural properties of series connected Ni nanogaps was achieved by using the activation [2, 3]. In this study, we investigated the application of the activation to the series-parallel-connected Au nanogaps for structurally defined, current-induced modification of nanogaps.
First, 2x1-6x6 series-parallel-connected Au nanogaps with the initial gap separation of 40-70 nm were fabricated with electron-beam lithography and lift-off processes. After the activation, the total resistance of the series-parallel-connected nanogaps became smaller than that before the activation. According to scanning electron microscope images, the current was passed thorough the narrower initial gaps within the series-parallel-connected nanogaps, and the separations of nanogaps were narrowed to less than 10 nm after the activation. Furthermore, we applied the activation to Au nanodots with interdot spacing of 30-50 nm placed between Au nanogap electrodes. As a result, the total resistances and the interdot spacing of Au nanodots were reduced by performing the activation. This tendency is quite similar to that of the series-parallel-connected Au nanogaps. These results clearly indicate that the structural properties of the series-parallel-connected Au nanogaps can be controlled simultaneously and precisely via the activation method. The understandings possibly imply that performing the activation to the series-parallel-connected nanogaps can be applicable to the shortest path problems.
References
[1] S. Kayashima, K. Takahashi, M. Motoyama and J. Shirakashi, Jpn. J. Appl. Phys., Part 2 46 (2007) L907.
[2] M. Ito, M. Yagi, K. Morihara and J. Shirakashi, J. Appl. Phys., 118 (2015) 014301.
[3] M. Ito, K. Morihara, T. Toyonaka, K. Takikawa and J. Shirakashi, J. Vac. Sci. Technol. B, 33 (2015) 051801.