Two-dimensional van der Waals electrical contact to monolayer MoSi₂N₄

A two-dimensional (2D) MoSi₂N₄ monolayer is an emerging class of air-stable 2D semiconductors possessing exceptional electrical and mechanical properties. Despite intensive recent research effort devoted to uncover the material properties of MoSi₂N₄, the physics of electrical contacts to MoSi₂N₄ remains largely unexplored thus far. In this work, we study van der Waals heterostructures composed of MoSi₂N₄ contacted by graphene and NbS₂ monolayers using first-principles density functional theory calculations. We show that the MoSi₂N₄/NbS₂ contact exhibits an ultralow Schottky barrier height (SBH), which is beneficial for nanoelectronics applications. For the MoSi₂N₄/graphene contact, the SBH can be modulated via the interlayer distance or via external electric fields, thus opening up an opportunity for reconfigurable and tunable nanoelectronic devices. Our findings provide insights into the physics of 2D electrical contacts to MoSi₂N₄ and shall offer a critical first step toward the design of high-performance electrical contacts to MoSi₂N₄-based 2D nanodevices.