Heterostructures with designable electronic interfaces represent the material foundation for novel electronic and optoelectronic devices. Conventionalheterostructures are usually linked together by covalent bonds and inherently limitedto materials with strict lattice-matching. The use of van der Waals (vdW) forces to assemble the building block materials allows for the combination of highly disparate materials beyond the lattice matching and processing compatibility limitations and enables the construction of versatile artificial vdW heterostructures. Here, we will discuss three vdW heterostructures assembled from low-dimensional materials, including 0D/2D, 2D/2D, 2D/3D heterojunctions and devices. Graphene/QDs[1,2] and graphene/MoS2 [3] heterostructures will be used to form photodetector devices. The third mixed-dimensional vdW (2D/3D) heterostructure will be discussed on the basis on the growth study of (In)GaN on graphene for the preparation of relaxed templates[4,5]

for light-emitting devices.

[1]G. Konstantatos et al., Nature Nanotechnology, 7 (2012) 363-368.

[2]S. Goossens et al., Nature Photonics, 11 (2017) 366-371.

[3]H. Xu et al., Small, 10, N°11(2014) 2300-2306.

[4]Y. Kim et al., Nature, 544 (2017), 340–343.

[5]W. Kong et al., Nat. Mater., 17 (2018), 999–1004.