Multilevel nonvolatile photomemory with long-term robust optical retention based on photoinduced depolarization

Ferroelectric memory is promising for implementing emerging information technologies, including digital storage and analog computing. Two-dimensional (2D) ferroelectric materials retain robust room-temperature ferroelectric characteristics at the single-layer limit, surpassing traditional ferroelectric materials. This characteristic enables further advancements in device miniaturization to meet the growing demand. Herein, we manufactured a metal-insulator-ferroelectric-semiconductor field-effect transistor (MIFSFET) using a 2D ferroelectric material (alpha-In2Se3), which displayed nonvolatile characteristics. Based on the mechanism of photoinduced depolarization in a ferroelectric semiconductor, the MIFSFET device can be used as a photomemory, capable of storing an optical image for up to 1000 s with minimal information loss and can achieve a multistate photoresponse induced by an optical pulse. Moreover, it can function as a ferroelectric memory, with an on/off ratio exceeding 10(6), endurance of above 3000 cycles, and stable retention. The proposed MIFSFET demonstrated excellent optical image sensing and memory functions, presenting a feasible approach for developing efficient visual systems in the future.