Narrow‐Bandgap Ferroelectric AgVP ₂ S ₆ ‐Modulated Multilayer‐Stacked 2D Heterojunction for Infrared‐Optical‐Readable Information Storage

ABSTRACT The 2D narrow‐bandgap ferroelectric materials are pivotal for advancing optical‐readable ferroelectric non‐volatile memories (Fe‐NVMs), as their narrow bandgap enables efficient absorption of near‐infrared (NIR) light, while intrinsic ferroelectricity supports non‐volatile modulation of photoelectric properties. Herein, we have designed a multilayer‐stacked gold/black phosphorus/AgVP 2 S 6 /graphene (Au/BP/AgVP 2 S 6 /Gr) heterojunction with a co‐directional step potential gradient, which achieves infrared‐optical‐readable information storage capability by leveraging AgVP 2 S 6 ’s polarization switching to dynamically regulate the built‐in electric fields. Although its on/off state ratio is only 10.2 (7.36 mW/cm 2 ), it exhibits a responsivity ( R ) of 100.7 and 6.9 mA/W, and a specific detectivity ( D *) of 1.81 × 10 10 and 3.2 × 10 9 Jones, corresponding to the on/off states, respectively. Furthermore, ferroelectric polarization exerts a significant modulation effect on its light polarization sensitivity, with the polarization ratio tunable over 4.4–8.5 between the on/off states, and infrared optical readout information storage still achievable under polarized light. This work provides a viable strategy for high‐performance infrared optical readout Fe‐NVMs.