Ferroelectric Field-Effect Transistors Based on MoS and CuInPS Two-Dimensional van der Waals Heterostructure.

We demonstrate room-temperature ferroelectric field-effect transistors (Fe-FETs) with MoS and CuInPS two-dimensional (2D) van der Waals heterostructure. The ferroelectric CuInPS is a 2D ferroelectric insulator, integrated on top of MoS channel providing a 2D/2D semiconductor/insulator interface without dangling bonds. The MoS- and CuInPS-based 2D van der Waals heterostructure Fe-FETs exhibit a clear counterclockwise hysteresis loop in transfer characteristics, demonstrating their ferroelectric properties. This stable nonvolatile memory property can also be modulated by the back-gate bias of the MoS transistors because of the tuning of capacitance matching between the MoS channel and the ferroelectric CuInPS, leading to the enhancement of the on/off current ratio. Meanwhile, the CuInPS thin film also shows resistive switching characteristics with more than four orders of on/off ratio between low- and high-resistance states, which is also promising for resistive random-access memory applications.