Switching of Volatile/Non‐Volatile Photonic Synapses via Metal/Semiconductor Interface Engineering for Bio‐Inspired Sensory Processing

Neuromorphic artificial photonic synapses have garnered significant attention for their emulation of the biological perception, learning, and memory functionalities, and are recognized as a potential solution to overcome the von Neumann bottleneck. However, it is still challenging to manipulate the volatile/non‐volatile photoconductance of a device without changing the photoactive component and architecture. In this study, we developed a synaptic device with a metal‐semiconductor‐metal architecture utilizing a single ZnO microwire. By engineering the metal‐semiconductor contact configurations via a simple annealing, specifically modulating the band engineering and interface states within the device, we successfully switch its volatile/non‐volatile photoconductance state. Furthermore, synaptic functionalities, including paired‐pulse facilitation, short‐term plasticity, long‐term plasticity, and polarization‐dependent plasticity, are replicated under both operational modes. The volatile mode showcases high‐pass filtering capabilities for in‐sensor image sharpening, while the non‐volatile mode enables multi‐state data storage and processing. The proposed dual‐mode synergy mechanism overcomes the functional limitations of traditional synaptic devices and provides new insights for developing multidimensional artificial synapse systems.