Anisotropic Resonant Tunneling in Twist-Stacked van der Waals Heterostructure

Abstract

Resonant tunneling, with energy and momentum conservation, has been extensively studied in two-dimensional van der Waals heterostructures and has potential applications in band structure probing, multivalued logic, and oscillators. Lattice alignment is crucial in resonant tunneling transistors (RTTs) for achieving negative differential resistance (NDR) with a high peak-to-valley ratio (PVR) because twist-angle-induced momentum mismatch can break the resonant tunneling condition. Here, we report anisotropic resonant tunneling in twist-stacked ReSe₂/h-BN/ReSe₂ RTTs, where the PVR exhibits a strong dependence on the twist angle between the two ReSe₂ layers, reaching a maximum at the twist angle of 102°. Theoretical calculations suggest that the twist angle modulates the joint density of states of the two anisotropic bands in ReSe₂ layers during the tunneling process, significantly suppressing the valley current and thereby enhancing the PVR. Double NDR peaks were observed in twist-stacked RTTs, which are attributed to interband resonant tunneling. Moreover, our twist-stacked RTTs are utilized in multibit inverters and adjustable self-powered photodetectors, providing potentials for the design of high-performance RTTs and photodetectors via twist-stacked engineering.