Investigation of resistive switching in lead-free bismuth–silver halide double perovskite

In this work, lead-free double perovskite Cs2BiAgBr6 film is fabricated and employed into resistive switching (RS) memory device with a metal/insulator/metal structure. The RS performances of the prepared device are examined both experimentally and theoretically. High-quality Cs2BiAgBr6 film is fabricated via a post-vacuum treatment and characterized systematically. In the prepared memory device, bipolar RS is observed with a high ON/OFF ratio, and the retention and endurance performances are measured. First-principles calculations based on the density functional theory reveal that the bromide vacancies (VBr) in Cs2BiAgBr6 render it metallic characteristics. Therefore, we propose that the migration of VBr under electrical fields formed and ruptured the conductive filament, leading to the RS behaviors of memory device.