High‐Entropy Perovskite Oxide Photonic Synapses

Abstract High‐entropy oxides are garnering increased attention due to their unique properties engineered by chemical disorders. Chemical disorders can cause random potential spatial fluctuations and the resulting anomalous photoconductivity, while they have not yet been exploited in high‐entropy oxides for usefulness. In this work, persistent photoconductivity (PPC) behavior in high‐entropy perovskite Ba(Zr_0.2Sn_0.2Ti_0.2Hf_0.2Nb_0.2)O₃ thin films is reported and used it as a basis to develop artificial photonic synapses. This photonic synapse can emulate distinctive biological synaptic features such as excitatory postsynaptic current, paired‐pulse facilitation, transition from short‐term memory to long‐term memory, and learning‐forgetting processes. This photonic synapse can also implement the basic “AND” and “OR” logic operations. In addition, a 5×5 photonic synaptic array is built to mimic the spatiotemporal sensing and memory functions of a visual sensing‐memory system, exhibiting the improved accuracy of dynamic machine vision classification tasks as compared to traditional visual sensing systems. This study highlights the potential of high‐entropy oxides for application in neuromorphic computing and dynamic machine vision systems.