Multifunctional Device With Switchable Hysteresis Direction Based on Multilayer rMoS₂

Recent advancements in 2D ferroelectric materials have enabled significant progress in electronic and optoelectronic devices. However, most studies have focused on single-function implementations, lacking the flexibility to switch between multiple functionalities. In this work, a multifunctional device based on a multilayer rhombohedral molybdenum disulfide (rMoS₂)/hexagonal boron nitride (h-BN) heterostructure is presented with electrically tunable hysteresis direction, integrating two operational modes: (1) Ferroelectric semiconductor field-effect transistor (FeSFET) and (2) Ferroelectric-Floating gate field-effect transistor (Fe-FGFET). The designed dual-mode device exhibits optoelectronic programmability, achieving more than 4-bit conductance states with a retention time of exceeding 120s. The system performance remains stable through 100 consecutive program/erase cycles with <1% conductance drift. Furthermore, synergistic electrical-optical modulation enables the emulation of biological synaptic functions, including the transition from short-term to long-term potentiation with tunable retention, and paired-pulse facilitation (PPF). These results establish multilayer rMoS₂ as a promising candidate for multifunctional electronics, providing enhanced flexibility and potential for integrated multifunctional applications, while paving the way for the development of advanced ferroelectric devices leveraging 2D ferroelectrics.