Mechanism of Dipole Moment Effect on the Schottky Barrier at Janus MoSH/MoSiGeN ₄ Metal–Semiconductor Interfaces

Controlling the Schottky barrier (SB) at metal–semiconductor interfaces is crucial for achieving efficient carrier injection in two-dimensional electronic devices. The dipole moment crucially governs the Schottky barrier height (SBH) in Janus van der Waals heterostructures (vdWHs). However, the physical mechanism of dipole moment-controlled SB remains unclear. Furthermore, how external tuning manipulates dipoles to achieve SBH control remains a challenge. Here, based on the first-principle calculations, we have investigated the interfacial electronic properties, dipole moment, and modulation of SB and tunneling properties for Janus MoSH/MoSiGeN 4 vdWH. We identify the potential step Δ V as the decisive quantity governing the SBH, which can be continuously tuned between 0.41 eV and 0.98 eV, resulting in p -type or n -type Schottky contacts (ShC). This Δ V originates from the synergistic interplay between the intrinsic and interface dipole moments, establishing a clear physical mechanism for the observed SBH variation. Furthermore, external electric fields and interlayer distance can effectively modulate the SBH by altering the total dipole moment and the resulting Δ V . Finally, compared to electric fields, reducing the interlayer distance more significantly enhances the tunneling probability and lowers the tunneling-specific resistivity. Our findings reveal the fundamental physics governing contact behavior in this Janus-based heterostructure and provide practical design guidelines.