Spatially Resolved Light‐Induced Ferroelectric Polarization in α‐In2Se3/Te Heterojunctions

Light‐induced ferroelectric polarization in 2D layered ferroelectric materials holds promise in photodetectors with multilevel current and reconfigurable capabilities. However, translating this potential into practical applications for high‐density optoelectronic information storage remains challenging. In this work, an α‐In2Se3/Te heterojunction design that demonstrates spatially resolved, multilevel, nonvolatile photoresponsivity is presented. Using photocurrent mapping, the spatially localized light‐induced poling state (LIPS) is visualized in the junction region. This localized ferroelectric polarization induced by illumination enables the heterojunction to exhibit enhanced photoresponsivity. Unlike previous reports that observe multilevel polarization enhancement in electrical resistance, the device shows nonvolatile photoresponsivity enhancement under illumination. After polarization saturation, the photocurrent increases up to 1000 times, from 10−12 to 10−9 A under the irradiation of a 520 nm laser with a power of 1.69 nW, compared to the initial state in a self‐driven mode. The photodetector exhibits high detectivity of 4.6×1010 Jones, with a rise time of 27 µs and a fall time of 28 µs. Furthermore, the device's localized poling characteristics and multilevel photoresponse enable spatially multiplexed optical information storage. These results advance the understanding of LIPS in 2D ferroelectric materials, paving the way for optoelectronic information storage technologies. This study visualizes light‐induced ferroelectric polarization in an α‐In₂Se₃/Te heterojunction using photocurrent mapping. The device shows nonvolatile photoresponsivity with photocurrent enhancement up to 1000 times after polarization saturation. These findings demonstrate the potential of 2D ferroelectric materials for advanced photodetectors and optical information storage applications.