Edge-Based Two-Dimensional α-InSe-MoS Ferroelectric Field Effect Device.

Heterostructures based on two-dimensional materials offer the possibility to achieve synergistic functionalities, which otherwise remain secluded by their individual counterparts. Herein, ferroelectric polarization switching in α-InSe has been utilized to engineer multilevel nonvolatile conduction states in a partially overlapping α-InSe-MoS-based ferroelectric semiconducting field effect device. In particular, we demonstrate how the intercoupled ferroelectric nature of α-InSe allows to nonvolatilely switch between - and -- type junction configurations based on a novel edge state actuation mechanism, paving the way for subnanometric scale nonvolatile device miniaturization. Furthermore, the induced asymmetric polarization enables enhanced photogenerated carriers' separation, resulting in an extremely high photoresponse of ∼1275 A/W in the visible range and strong nonvolatile modulation of the bright A- and B- excitonic emission channels in the overlaying MoS monolayer. Our results show significant potential to harness the switchable polarization in partially overlapping α-InSe-MoS based FeFETs to engineer multimodal, nonvolatile nanoscale electronic and optoelectronic devices.