Superionic Silver Halide Solid Electrolyte: Dielectric Property and Iontronic Memtransistor Application for Bioinspired Computing

Abstract

Technology like high-level parallel information processing and storage in the brain remains a dream to the researchers using conventional solid-state electronics. Here, a robust thin film bilayer superionic dielectric of poly(ethylene oxide) (PEO) and rubidium silver iodide (RbAg4I5) is developed to fabricate solid-state iontronic synaptic memtransistors, which can serve as the basic building blocks for the hardware-implementation of neuromorphic computing. X-ray photoelectron spectroscopy and impedance measurements precisely confirm the stoichiometric composition of RbAg4I5 and dielectric nature combining with a PEO layer, respectively. The superionic bilayer PEO/RbAg4I5 gating effectively modulates the channel conductance analogously and displays memtransistor functionality. Interestingly, the transfer curves depict a colossal hysteresis yielding negative differential transconductance of peak-to-valley ratio up to 5 × 103 after the gate-controlled resistive switching. Systematic electrical characterizations reveal a variety of synaptic behaviors, including the inhibitory postsynaptic current, paired-pulse depression, and potentiation/depression curve. Finally, an artificial neural network for off-chip digit recognition is simulated to assess the performance of the device for the neuromorphic application and achieved a test accuracy of 95.94% on the Modified National Institute of Standards and Technology dataset.