High-Performance Photoresponse and Nonvolatile Photomemory Effect in a Partially Gated MoS2/α-In2Se3 Heterojunction Photodetector

2D ferroelectric materials exhibit exceptional properties such as atomically thin layers, strong ferroelectric polarization, high carrier mobility, and suitable band gaps, making them highly promising for electronics, optoelectronics, ferroelectronics, and nonvolatile memory applications. In this study, we present a partially gated MoS₂/α-In₂Se₃ heterojunction photodetector that allows the manipulation of ferroelectric polarization in α-In₂Se₃ by both gate and drain voltages. The device shows excellent photoresponse performance and a nonvolatile photomemory effect. It achieves a maximum photoresponsivity of ∼698 A/W at 405 nm, ∼1210 A/W at 473 nm, ∼1076 A/W at 515 nm, and ∼1306 A/W at 638 nm. By enhancing the ferroelectric polarization of α-In₂Se₃, the photoresponsivity, external quantum efficiency, and detectivity are greatly improved. The photomemory effect has an extremely long retention time exceeding 4000 s with an expected information retention rate of over 95% after 10 years. The device performance is a result of the combined effects of vertical-electric-field-controlled ferroelectric polarization, horizontal-electric-field-controlled ferroelectric polarization, and light-induced depolarization. The proposed partially gated MoS₂/α-In₂Se₃ heterostructure provides a new perspective for designing 2D ferroelectric devices with significant potential for optoelectronics and nonvolatile memory applications.