Resonant Tunneling Oscillators Based on WSe2/h-BN/WSe2 van der Waals Double Quantum Wells.

A van der Waals (vdW) heterostructure of few-layer (FL)-WSe2/FL-h-BN/FL-WSe2 exhibits resonant tunneling between the WSe2 subbands through the h-BN barrier, analogous to that in conventional double-quantum-well (DQW) structures. This resonant tunneling in the vdW DQW device gives rise to pronounced negative differential resistance (NDR). Utilizing this NDR, we demonstrate a resonant tunneling oscillator: when the vdW DQW device is integrated into an LC resonant circuit and biased within its NDR region, sustained AC voltage oscillations are achieved with frequencies exceeding 1 MHz. Furthermore, a comparison of the oscillation characteristics of two different devices indicates that lowering the device resistance is a viable route toward higher-frequency operation. This work represents the first realization of oscillators based on resonant tunneling between transition-metal dichalcogenide layers, significantly broadening the potential of vdW electronics.