Field-Driven Solid-State\nDefect Control of Bilayer\nSwitching Devices

We develop a framework for controlling and investigating\nreversible\nionic transfer between two solid metal oxides layers by examining\nfield-driven changes in electrical properties of the thin film bilayer\noxide system Pr<sub>0.1</sub>Ce<sub>0.9</sub>O<sub>2</sub>/La<sub>1.85</sub>Ce<sub>0.15</sub>CuO<sub>4</sub> (PCO/LCCO). We show that\nwe can reversibly redistribute oxygen ions by applied voltage in a\nhighly controlled and reversible fashion near ambient temperatures\nover large oxygen ion activity limits, which, for the first time,\nis directly interpretable by defect chemical models. This allowed\nus to determine how defect concentrations in each layer systematically\nvaried with voltage and the subsequent impact on each film’s\nconductance. These results showcase the relevance and applicability\nof defect chemical models, traditionally considered only at elevated\ntemperatures, to the development of bilayer devices of importance\nto neuromorphic memory applications. This allows for a more systematic\napproach for studying and understanding the solid–solid exchange\nprocess in electrochemically controlled microelectronic devices. Moreover,\nour work sets the foundation for the development of large-area field-driven\ndefect-controlled bilayer switching devices with potential application\nto a broad array of functionally modulated devices.