Edge-Based\nTwo-Dimensional α‑In2Se3–MoS2 Ferroelectric Field Effect\nDevice

Heterostructures\nbased on two-dimensional materials offer the possibility\nto achieve synergistic functionalities, which otherwise remain secluded\nby their individual counterparts. Herein, ferroelectric polarization\nswitching in α-In2Se3 has been utilized\nto engineer multilevel nonvolatile conduction states in a partially\noverlapping α-In2Se3–MoS2-based ferroelectric semiconducting field effect device. In particular,\nwe demonstrate how the intercoupled ferroelectric nature of α-In2Se3 allows to nonvolatilely switch between n-i and n-i-n type junction configurations based on a novel\nedge state actuation mechanism, paving the way for subnanometric scale\nnonvolatile device miniaturization. Furthermore, the induced asymmetric\npolarization enables enhanced photogenerated carriers’ separation,\nresulting in an extremely high photoresponse of ∼1275 A/W in\nthe visible range and strong nonvolatile modulation of the bright\nA- and B- excitonic emission channels in the overlaying MoS2 monolayer. Our results show significant potential to harness the\nswitchable polarization in partially overlapping α-In2Se3–MoS2 based FeFETs to engineer multimodal,\nnonvolatile nanoscale electronic and optoelectronic devices.