▎ 摘　　要

Dirac semimetal is an emerging class of quantum matters, ranging from 2D category, such as, graphene and surface states of topological insulator to 3D category, for instance, Cd3As2 and Na3Bi. As 3D Dirac semimetals typically possess Fermi-arc surface states, the 2D-3D Dirac van der Waals heterostructures should be promising for future electronics. Here, graphene-Cd3As2 heterostructures are fabricated through direct layer-by-layer stacking. The electronic coupling results in a notable interlayer charge transfer, which enables us to modulate the Fermi level of graphene through Cd3As2. A planar graphene p-n-p junction is achieved by selective modification, which demonstrates quantized conductance plateaus. Moreover, compared with the bare graphene device, the graphene-Cd3As2 hybrid device presents large nonlocal signals near the Dirac point due to the charge transfer from the spin-polarized surface states in the adjacent Cd3As2. The results enrich the family of van der Waals heterostructure and should inspire more studies on the application of Dirac/Weyl semimetals in spintronics.