Atomic level Thin-film And Devices laboratory

Two-dimensional in-plane transition-metal dichalcogenide (TMD) junctions have a range of potential applications in next-generation electronic devices. However, limited by the difficulties in ion implantation on 2D systems, the fabrication of the in-plane TMD junctions still relies on the lateral epitaxy of different materials, which always induces lattice mismatch and interfacial scattering. Here, we report the in-plane TMD junction formed with monolayer (ML) PtTe₂ at the boundary of ML and bilayer graphene on SiC. As the scanning tunneling microscopy/spectroscopy results revealed, the substrate screen effect is weak on ML PtTe₂, compared to the nonlayered materials. At the interface of the junction, the atomic lattice is continuous, and a smooth type-II band alignment is formed with a near-zero band offset. The reported technique can be readily extended to other 2D semiconductors with strong interlayer coupling and is feasible for fabricating TMD junctions with promising interfacial electronic structures, aimed at device applications based on low-dimensional electronic behaviors.