Synthetic Metal-Semiconductor Junctions of Transition Metal Disulfides

Transition metal dichalcogenides (TMDs), a group of 2D materials with diverse electronic properties, are ideal candidates to build atomically thin electronics. Although critical components of an electronic device based on TMDs, such as insulator-semiconductor and semiconductor-semiconductor junctions, have been demonstrated, there is limited experimental realization of TMD-based metal-semiconductor junctions to date. Here, we report a two-step chemical vapor deposition (CVD) strategy that enables the synthesis of high-quality solely TMD-made metal-semiconductor lateral junctions. Remarkably, we discover a novel growth behavior in such lateral TMD heterojunctions: MoS₂ was found to nucleate from the vertexes of multilayered VS₂ flakes and evolve into monolayer polycrystals, rather than the edge epitaxy observed in other TMD lateral junctions. Furthermore, we demonstrate that lattice coherency across the lateral junction is not a necessity for low-resistance contacts, as our VS₂-MoS₂ junctions manifest contact resistance as low as 500 Ωµm and a Schottky barrier height as small as 30 meV, both among the best values reported to date for contacts to 2D TMDs. This work opens up a new avenue for all-2D-based synthetic electronics.