Graphene-based in-plane heterostructures for atomically thin electronics

Two-dimensional materials are promising for use in atomically thin electronics, optoelectronics and flexible electronics because of their versatile band structures, optical transparency, easy transfer to a substrate and compatibility with current technology for integrated circuits. Three key components of contemporary integrated circuits, metals, insulators and semiconductors, have analogues in two-dimensional materials, i.e., graphene, boron nitride (BN) and transition metal dichalcogenides (TMDCs), respectively. Their controlled integration in a single layer is essential for achieving completely two-dimensional devices. In this review, we briefly describe the latest advances in graphene-based planar heterostructures, in graphene-BN, and in graphene-TMDC heterojunctions, focusing on the fabrication methods, the interfacial structure characteristics at the atomic scale and the properties of prototype electronic devices. The challenges and prospects in this field are also discussed.