Mixed-dimensional van der Waals heterostructures: Synthesis, properties, and applications

Mixed-dimensional van der Waals (vdW) hetero-integration, in which different materials are physically assembled through vdW forces, offers a promising bond-free integration strategy without lattice matching and processing limitations. Owing to their self-passivated and dangling-bond-free surface, two-dimensional (2D) layered materials can integrate with non-2D materials through vdW interactions. Here, we review the state-of-the-art multifunctional devices made from mixed-dimensional vdW heterostructures. By combining materials of differing dimensionalities, the vdW heterostructures with atomically sharp interfaces and highly distinct electronic functions offer a new material platform for fundamental studies that probe the generation, transport, and confinement of charges, excitons, phonons, and photons. Finally, wafer-scale growth of mixed-dimensional vdW heterostructures is also discussed for future applications in electronics, energy, and photonics. We highlight the contributions made in this issue on synthesis, properties, and applications of mixed-dimensional heterostructures in various domains and project future growth directions for the field.