Resistive switching memory performance in oxide hetero-nanocrystals with well-controlled interfaces

• Main Authors: Takafumi Ishibe, Yoshiki Maeda, Tsukasa Terada, Nobuyasu Naruse, Yutaka Mera, Eiichi Kobayashi, Yoshiaki Nakamura
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2020-01-01
• Series: Science and Technology of Advanced Materials
• Subjects: memristor; interface control; nanocrystal; iron oxide; silicon; germanium; resistive switching characteristics
• Online Access: http://dx.doi.org/10.1080/14686996.2020.1736948

For realization of new informative systems, the memristor working like synapse has drawn much attention. We developed isolated high-density Fe3O4 nanocrystals on Ge nuclei/Si with uniform and high resistive switching performance using low-temperature growth. The Fe3O4 nanocrystals on Ge nuclei had a well-controlled interface (Fe3O4/GeOx/Ge) composed of high-crystallinity Fe3O4 and high-quality GeOx layers. The nanocrystals showed uniform resistive switching characteristics (high switching probability of ~90%) and relatively high Off/On resistance ratio (~58). The high-quality interface enables electric field application to Fe3O4 and GeOx near the interface, which leads to effective positively charged oxygen vacancy movement, resulting in high-performance resistive switching. Furthermore, we successfully observed memory effect in nanocrystals with well-controlled interface. The experimental confirmation of the memory effect existence even in ultrasmall nanocrystals is significant for realizing non-volatile nanocrystal memory leading to neuromorphic devices.