Atomic-scale tuning of ultrathin memristors

Abstract

Abstract Continuous device downsizing and circuit complexity have motivated atomic-scale tuning of memristors. Herein, we report atomically tunable Pd/M1/M2/Al ultrathin (<2.5 nm M1/M2 bilayer oxide thickness) memristors using in vacuo atomic layer deposition by controlled insertion of MgO atomic layers into pristine Al 2 O 3 atomic layer stacks guided by theory predicted Fermi energy lowering leading to a higher high state resistance (HRS) and a reduction of oxygen vacancy formation energy. Excitingly, memristors with HRS and on/off ratio increasing exponentially with M1/M2 thickness in the range 1.2–2.4 nm have been obtained, illustrating tunneling mechanism and tunable on/off ratio in the range of 10–104. Further dynamic tunability of on/off ratio by electric field is possible by designing of the atomic M2 layer and M1/M2 interface. This result probes ways in the design of memristors with atomically tunable performance parameters.