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

For realization of new informative systems, the memristor working like synapse has drawn much attention. We developed isolated high-density Fe ₃ O ₄ nanocrystals on Ge nuclei/Si with uniform and high resistive switching performance using low-temperature growth. The Fe ₃ O ₄ nanocrystals on Ge nuclei had a well-controlled interface (Fe ₃ O ₄ /GeO _x /Ge) composed of high-crystallinity Fe ₃ O ₄ and high-quality GeO _x 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 Fe ₃ O ₄ and GeO _x 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.
(© 2020 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)