Ultrafast van der Waals diode using graphene quantum capacitance and Fermi-level depinning.

Graphene, with superior electrical tunabilities, has arisen as a multifunctional insertion layer in vertically stacked devices. Although the role of graphene inserted in metal-semiconductor junctions has been well investigated in quasi-static charge transport regime, the implication of graphene insertion at ultrahigh frequencies has rarely been considered. Here, we demonstrate the diode operation of vertical Pt/n-MoSe/graphene/Au assemblies at ~200-GHz cutoff frequency (f).

5 nm Ultrathin Crystalline Ferroelectric P(VDF-TrFE)-Brush Tuned for Hysteresis-Free Sub 60 mV dec Negative-Capacitance Transistors.

Negative-capacitance field-effect transistors (NC-FETs) have gathered enormous interest as a way to reduce subthreshold swing (SS) and overcome the issue of power dissipation in modern integrated circuits. For stable NC behavior at low operating voltages, the development of ultrathin ferroelectrics (FE), which are compatible with the industrial process, is of great interest. Here, a new scalable ultrathin ferroelectric polymer layer is developed based on trichloromethyl (CCl )-terminated poly(vinylidene difluoride-co-trifloroethylene) (P(VDF-TrFE)) to achieve the state-of-the-art performance of NC-FETs.