Ferroelectric polarization modulated optoelectronic synapses based on BaTiO/TiO heterojunction for non-volatile visual memory.

The growing demand for neuromorphic computing architectures that mimic biological information processing has driven extensive research on optoelectronic synapses with multimodal neuromodulation capabilities. In this study, BaTiO/TiO optoelectronic synaptic devices with high non-volatile memory characteristics were constructed by interfacial energy band engineering. This heterojunction synaptic device achieves a 1350 % enhancement in relaxation time (τ = 84.14 s) compared to conventional BaTiO device (τ = 6.21 s). Moreover, short-term to long-term memory conversion and the cognitive process of "learning experience" are achieved by adjusting light pulse parameters. Through further investigation, a synergistic ferroelectric polarization strategy is proposed, demonstrating that downward polarization extends τ to 202.93 s, with image retention time exceeding 4800 s. The synaptic device demonstrates biological-level energy efficiency (10.45 fJ) while achieving 97.5 % and 89.05 % recognition accuracy on MNIST and Fashion-MNIST datasets, respectively, through convolutional neural networks. This work not only exhibits the application prospect of ferroelectric semiconductor-based heterojunction in artificial optoelectronic synapse but also provides new ideas for the design and application of multimodal neuromorphic devices.