A Self-Powered Van der Waals Nonvolatile Ferroelectric Memory Utilizing the Ferro-Pyro-Phototronic Effect

Due to ferroelectric polarization's reversibility, the ferro-pyro-phototronic effect-induced current can switch direction, endowing materials with light-based info storage/reading abilities and promoting self-powered memories. Currently, research on 2D ferroelectric materials for such memories is in its early stages. In this report, the non-volatile and reversible polarization of CuCrP₂S₆ is exploited to create a memory device with a switching ratio exceeding 10³, and by combining it with the ferro-pyro-phototronic effect, the device also achieves self-powered optical readout. When reading under weak light at 405 nm, both storage states exhibit highly stable retention capabilities for up to 2 × 10³ s, and furthermore, after undergoing 10⁶ polarization switching cycles at 2 V, demonstrating outstanding fatigue resistance. The device shows an excellent photoresponse to light with wavelengths of 405, 660, and 808 nm. Specifically, under zero bias and for 405 nm weak light (0.08 mW cm^-2), it achieves a responsivity of 4.47 mA W^-1, a specific detectivity of 2.42 × 10¹⁰ Jones. Moreover, its pyroelectric coefficient is over 2.622 × 10³ µC m^-2 K^-1. Overall, the device realizes highly stable dual storage states, self-powered optical readout, multi-band photoresponse, and high-sensitivity photodetection, thereby opening up an innovative technological pathway for the development of smart electronics.