Band Modulation of Black Phosphorus and Molybdenum Disulfide van der Waals Heterojunction: Twist and Electric Field Effects

The understanding of band modulation and related band alignment in van der Waals heterojunctions (vdW HJs) is of great importance to their electronic properties and potential applications in the field of nanoelectronic devices. In our work, we investigate the band evolution and band alignment of black phosphorus (BP) and molybdenum disulfide (MoS2) vdW HJs under the approaches of twist and applied electric field using first-principles calculations. It is found that the positions and orbital contributions of conduction band minimum (CBM) and valence band maximum (VBM) in bilayer BP/MoS2 HJs will alter as the composition twists relative to each other, while the major orbital contributions that are d(2) states of Mo atoms and pz states of P atoms do not change. When applying an electric field, the band structure of bilayer BP/MoS2 HJs can experience type-II/I/II, indirect/direct/indirect, and semiconductor/metal transitions, respectively. The underlying mechanism on the twist effect and electric field modulation of electronic properties in BP/MoS2 HJs has been clarified in detail. Our results provide some essential information for the band engineering of BP/MoS2 HJ and future device fabrication.