Gate-Tunable Negative Differential Resistance Behaviors in a hBN-Encapsulated BP-MoS2 Heterojunction

Two-dimensional (2D) heterostructures show great potential in achieving negative differential resistance (NDR) effects by Esaki diodes and or resonant tunneling diodes. However, most of the reported Esaki diode-based NDR devices realized by bulk 2D films lack sufficient gate tunability, and the tuning of NDR behavior from appearing to vanishing remains elusive. Here, a gate-tunable NDR device is reported based on a vertically stacked black phosphorus (BP) and molybdenum disulfide (MoS2) thin 2D heterojunction. At room temperature, a rectifying ratio of similar to 6 orders of magnitude from a reverse rectifying diode to a forward rectifying diode by gate modulation is obtained. Through analyzing the temperature-dependent electrical properties, the tunneling mechanism at a certain gate voltage range is revealed. Moreover, the switchable and continuously gate-tunable NDR behavior is realized with a maximum peak-to-valley ratio of 1.23 at 77 K, as shown in the I-DS mappings by sweeping V-DS under different V-GS. In addition, a compact model for gate-tunable NDR behavior in 2D heterostructures is proposed. To our best knowledge, this is the first demonstration of NDR behavior in BP-MoS2 heterostructures. Consequently, this work sheds light on the gate-tunable NDR devices and reconfigurable logic devices for realizing ternary and reconfigurable logic systems.

Automated summary

This study reports a gate-tunable NDR device based on a vertically stacked black phosphorus and molybdenum disulfide thin 2D heterojunction, achieving a rectifying ratio of about 6 orders of magnitude by gate modulation at room temperature. The mechanism of tunneling in a certain gate voltage range is revealed through temperature-dependent electrical properties analysis. Additionally, switchable and continuously gate-tunable NDR behavior is demonstrated with a peak-to-valley ratio of 1.23 at 77K.