High-linearity all-2D heterojunction-based neuromorphic image-sensing transistor array with a sandwiched tunneling...

Neuromorphic visual systems have attracted tremendous attention for their in-sensor image sensing and information preprocessing paradigm that replicates human visual system. However, current neuromorphic visual devices employed in these systems still confront challenges on lateral conductivity, air-stability, and photo-response linearity. Here, we demonstrate a neuromorphic image-sensing transistor array based on a tri-layer van der Waals heterostructure composed of MoS₂, (BA)₂PbI₄ and graphdiyne (GDY). The top MoS₂ layer with high intrinsic mobility serves as carrier-transport channel, while encapsulating the 2D perovskite to shield it from ambient air. The sandwiched 2D-(BA)₂PbI₄ nanosheet converts light into electricity, and functions as a photo-tunable tunneling junction, facilitating unidirectional tunneling of photo-generated carriers toward the underlying GDY layer. GDY, featuring well-distributed alkyne bonds, enables uniform interaction and storage of charges. The device demonstrates long-term air-stability (>10 weeks), highly competitive linearity in synaptic transistor weight modulation (α_P = 0.006, α_D = 0.025), and remarkably low energy consumption (~41.8 aJ per synaptic event) among 2D heterojunction synaptic transistors. Furthermore, a hardware-level neuromorphic kernel constructed using a synaptic array of these heterostructure devices realizes spatiotemporal neuromorphic in-sensor dynamic image processing and trajectory detection for object movement. This work provides hardware architecture for the next-generation neuromorphic vision.