Electro-Optically Tunable Passivated Double-Cation Perovskite-Based ReRAM for Low-Power Memory Applications

Abstract

3-D Hybrid halide perovskites (HHPs) have garnered significant interest as a promising contender for next-generation resistive random access memory (ReRAM) technology. However, challenges such as variations in cycle-to-cycle switching iterations, operating voltages, and restrained reproducibility arise due to the disproportionate presence of grain size (GS) and grain boundaries (GBs), which are impediments to the widespread adoption of perovskite-based memory devices in commercial applications. Since GBs present in the thin film act as pathways for ion/cation migrations that eventually lead to the formation of conducting filament (CF), by regulating GBs, the resistive switching (RS) performance of the memory devices can also be improved. Herein, we initially optimized GS and thus GBs in the 3-D HHP thin film by the incorporation of FA+ in the MAPbI3 3-D HHP to prepare double-cation 3-D MAFAPbI3 HHP and determined that the doping of 10% FAI improved the MAFAPbI3 film quality with an average grain size of ∼209.68 and 6.65 nm surface roughness, resulting in higher GBs that led to the stable RS of the fabricated Ag/MAFAPbI3/FTO up to 491 cycles under dark conditions and 245 cycles under white light illumination with significantly low statistical variations (σ/μ %) in the consecutive switching cycles. This performance was achieved while maintaining low-resistance states (LRS) and high-resistance-states (HRS) ratios, i.e., LRS/HRS of ∼15.2 (dark) and ∼54.3 (white light) conditions at power consumption of ∼0.101 mW. Further, to improve LRS/HRS, the PEAI passivation layer was deposited over the optimized MAFAPbI3 switching layer (SL) through spin-coating, and the fabricated Ag/PEAI/MAFAPbI3/FTO ReRAM configuration exhibited LRS/HRS ∼105 at considerably low power, i.e., 0.12 and 0.23 mW while operating under dark and white light illumination, respectively. Furthermore, the RS mechanisms of Ag/MAFAPbI3/FTO and Ag/PEAI/MAFAPbI3/FTO were discussed and supported by the electrochemical metallization (ECM) model.