Low-Power Dual-Functional Neuromorphic Optoelectronic Device Based on Bi_4.15Nd_0.85Ti₃FeO₁₅/ZnO Heterojunction

Constructing multifunctional neuromorphic optoelectronic devices that integrate sensing, memory and computing is an important approach to overcome the computational bottlenecks of the traditional von Neumann architecture and improve the performance of artificial visual systems. In this work, a Bi₄.₁₅Nd₀.₈₅Ti₃FeO₁₅(BNTF)/ZnO ferroelectric-semiconductor heterojunction device was designed and fabricated via the sol-gel method, realizing the integration of self-powered photodetection and low-power optical synapse in a single two-terminal device. Under zero bias, the device exhibited polarization-tunable photoresponsivity (R_up/R_down = 4.1) with high response speed, and thus excellent imaging capability and photoelectric coupling logic operation functions. Under small bias voltage (≤0.5 V), it could act as an artificial optical synapse device and achieve multiple types of synaptic plasticity. Notably, by the self-denoising function of the optical synapse, the recognition accuracy of digit images improved from 87.5% to 96.8%. The in-sensor reservoir computing system based on BNTF/ZnO synapse array achieved a high accuracy of 97.3% in moving target recognition. The device also featured an ultralow power consumption of 4.6 fJ, matching or even lower than that of most biological synapses. This study revealed the unique advantages and application prospects of ferroelectric-semiconductor heterojunction devices in constructing low-power integrated imaging-memory-computing vision systems.