Fabrication of a p-Si/MoS 2 /WSe 2 bipolar junction transistor via a CVD-grown MoS 2 on p-type silicon

Abstract This study demonstrates the fabrication and characterization of a vertical heterojunction bipolar junction transistor (BJT) based on two-dimensional transition-metal dichalcogenides. Molybdenum disulfide (MoS 2 ) was directly grown on p-type silicon by chemical vapor deposition, serving as the base and forming a high-quality pn heterojunction with the emitter. Tungsten diselenide (WSe 2 ), prepared by chemical vapor transport and mechanically exfoliated, was stacked on MoS 2 to act as the collector. Electrical characterization of the p-Si/MoS 2 and MoS 2 /WSe 2 junctions confirmed their diode-like behavior with clear current–voltage rectification. The complete p-Si/MoS 2 /WSe 2 transistor operated in a common-emitter configuration, achieving an average current gain ( β ) of 329.2. These results verify the feasibility of integrating 2D materials into vertical BJT architectures and highlight the advantage of direct MoS 2 growth on silicon for efficient carrier transport and robust junction performance.