Interplay of ferroelectric polarization and defect engineering in semiconductor heterostructures for photovoltaic synaptic functionality

Emerging optoelectronic synaptic devices based on two-dimensional (2D) materials are extremely attractive in the field of artificial intelligence. However, in most reports, these devices either have single functions and high energy consumption. Based on photoinduced ferroelectric polarization reversal (CuInP2S6) and synergistic defect engineering (MoS2), we propose a 2D CuInP2S6–MoS2 two-terminal optoelectronic synapse device, which has a simple structure and a wide spectral photovoltaic response and ultralow power consumption, as low as 0.03 fJ under electric pulse stimulation and 0.5 fJ under light pulse stimulation. Most importantly, complex bionic behaviors, including acquisition, extinction, recovery, and generalization, were mimicked by light and electrical stimulation, respectively. Therefore, this efficient synaptic photovoltaic device can provide a scientific perspective for future bionic synapses and artificial intelligence.