Ultra-low subthreshold swing across five-decade in 2D negative capacitance Dirac source-drain MoS₂-Gr heterostructure field effect transistor

In conventional field effect transistors Boltzmann distribution sets a fundamental limit to achieve sub-60 subthreshold swing (SS) at room temperature. By converging the concepts of negative differential capacitance in 2D ferroelectric and localized density state of graphene source around the Dirac point we demonstrate a state-of-art device architecture that retains average SS of 13 mV/dec over five decades of drain current with the minimum SS of 4.8 mV/dec. The negative capacitance stems from double energy landscape in layered van der Waals material is verified by applying a voltage pulse across the CuInP₂S₆ capacitor and analyzing the inductance like transient voltage dynamics. Insightful investigation has been done to understand the physics behind the improved NC performance which differs from the previous reports. Further modified device structure is demonstrated, it provides mV order of hysteresis with reasonably low sub-thermionic SS. Our study could pave the way for potential ultra-low power electronics industry.