Janus VSSi as an efficient 2D electrode for Sb2C3 with tunable Schottky contact: a first-principles study.

Two-dimensional (2D) metal/semiconductor van der Waals (vdW) heterostructures have attracted significant attention for next-generation nanoelectronic devices due to their tunable interfacial properties. In this study, first-principles calculations are employed to comprehensively explore the structural stability, electronic behavior, and contact properties of the Janus VSSi/Sb2C3 heterostructure. Our results demonstrate that the heterostructure is energetically, mechanically, and dynamically stable. Depending on the interfacial configuration, distinct contact behaviors are observed, where the Si-terminated interface forms an ohmic contact, while the S-terminated interface exhibits an n-type Schottky contact with a relatively low barrier height, facilitating efficient electron injection. The absence of significant metal-induced gap states indicates weak Fermi level pinning, allowing the Schottky barrier to closely follow the Schottky-Mott limit. Furthermore, the tunneling probability and tunneling-specific resistivity confirm the presence of low contact resistance and efficient carrier transmission. Notably, the application of an external electric field enables effective modulation of the Schottky barrier and induces a transition between n-type and p-type contacts via band-edge engineering. These results establish Janus VSSi as a promising two-dimensional metallic electrode and highlight the VSSi/Sb2C3 heterostructure as a potential building block for future nanoelectronic and optoelectronic devices.