Proton Competitive Activities in Flexible Hydrogel Gated Oxide Neuromorphic Transistor for Mimicking Bienenstock– Cooper–Munro Learning Rule

Ionic modulation activities pose interesting strategy for modulating physical characteristics and electronic transport properties of condensed materials. With unique ionic/electronic interfacial coupling behaviors, ionic conductive electrolyte gated transistors have also been creatively proposed for neuromorphic electronic applications. In this work, a flexible gelatin-carboxylated chitosan (GEL-CCs) composite hydrogel electrolyte-gated indium tin oxide (ITO) transistor is fabricated. Due to self-proton modulation of the drain, interesting pseudo-diode mode is exhibited. With the loading of gate spikes and drain spikes, potentiation and depression synaptic responses are observed on transistor mode and pseudo-diode mode, respectively. Additionally, high-pass and low-pass filtering functions are realized on the two modes. Furthermore, with an effective synaptic weight updating strategy, high recognition accuracy of ~93.44% is addressed for Modified National Institute of Standards and Technology (MNIST) handwritten digits. Interestingly, proton competitive activities are observed for the gate and the drain. As leads to the implementation of enhanced depression effect (EDE) in Bienenstock–Cooper–Munro (BCM) learning rule, which has not been mimicked on previously reported neuromorphic transistors. The proton competitive activities in proton-gated oxide neuromorphic transistor pose a highly promising strategy for neuromorphic electronic applications.