Coherent Interlayer Tunneling and Negative Differential Resistance with High Current Density in Double Bilayer Graphene–WSe₂ Heterostructures

Abstract

We demonstrate gate-tunable resonant tunneling and negative differential resistance between two rotationally aligned bilayer graphene sheets separated by bilayer WSe. We observe large interlayer current densities of 2 and 2.5 μA/μm and peak-to-valley ratios approaching 4 and 6 at room temperature and 1.5 K, respectively, values that are comparable to epitaxially grown resonant tunneling heterostructures. An excellent agreement between theoretical calculations using a Lorentzian spectral function for the two-dimensional (2D) quasiparticle states, and the experimental data indicates that the interlayer current stems primarily from energy and in-plane momentum conserving 2D-2D tunneling, with minimal contributions from inelastic or non-momentum-conserving tunneling. We demonstrate narrow tunneling resonances with intrinsic half-widths of 4 and 6 meV at 1.5 and 300 K, respectively.

Quantum engineering of transistors based on 2D materials heterostructures

“…Several recent reports suggested [19] [20] that twisted layers of 2D materials can modify the transport properties of the stacked layers significantly. This method of forming heterostructures using 2D materials can significantly modify the band-structure and hence transport properties [19][20] [21].…”

Vertical Transistors Based on 2D Materials: Status and Prospects

“…In this context, using TMDs with a smaller bandgap as tunnel barriers may enhance the peak-to-valley ratio of the resonances in the electrical characteristics. Recently, Burg et al [78] demonstrated gate-tunable resonant tunneling and NDR between two rotationally-aligned bilayer Gr sheets separated by a bilayer WSe 2 . Remarkable large interlayer current densities of 2 µA/µm 2 and NDR peak-to-valley ratios of~4 were observed at room temperature in these device structures.…”

Independent Band Modulation in 2D van der Waals Heterostructures via a Novel Device Architecture

“…Resonate tunneling current and negative differential resistance (NDR) have been observed in graphene‐based heterostructure TFETs, including monolayer and bilayer graphene separated by BN25, 26, 27, 28, 29, 30 or TMDs 6, 31. However, due to the absence of a bandgap, graphene‐based TFETs are unable to obtain a high on/off ratio of the current.…”