Pressure-dependent current transport in vertical BP/MoS2 heterostructures.

Abstract

van der Waals heterostructures between two-dimensional (2D) materials offer versatile platforms for innovative electrical device architectures and applications. Black phosphorus (BP) and molybdenum disulfide (MoS₂) emerge as promising candidates for heterostructures, owing to their exceptional electronic properties and gate-tunable capabilities. In this work, we study the electrical properties of a vertical BP/MoS₂ heterostructure fabricated onto a SiO₂/Si substrate in a back-gate configuration. We focus on the effect of air pressure, from atmospheric pressure to 10^-4 mbar, and show that best electrical performances are enabled at the lower pressure. The heterostructure exhibits gate-tunable rectifying current-voltage characteristics, with a rectification ratio close to 10³. The rectifying characteristics present a kink in the forward region revealing different conduction mechanisms, namely drift-diffusion and band-to-band tunneling. Furthermore, when used as a transistor, the device shows n-type conduction, high gate modulation with ON/OFF ratio of ${10}^6$ , low off-state current of ${10}^{-14}A$ and mobility of 1.6 cm² V^-1 s^-1. The results of this work highlight the potential of BP/MoS₂ heterostructures for applications in low-power electronics, high-performance transistors, and sensitive pressure sensors.