Functional hetero-interfaces in atomically thin materials

Interfaces are often crucial determinants of the physicochemical properties of a material. As a result, the rational production and engineering of heterogeneities, and the resulting interfaces, can enhance the functionality of a material system. This is especially true of two dimensional (2D) materials, which are only a few atoms thick and thus sensitive to small perturbations of their surroundings. As a result, 2D materials and their heterostructures have been recently modified to function as catalysts, photodetectors, chemical sensors, memory, logic devices, single photon emitters, and more. In this review, we summarize the current understanding of functional interfaces in few-layered chalcogenide 2D systems, and address the following topics: The classification of interfaces by dimensionality and electronic structure, methods of creating 2D interfaces, characterization techniques and related challenges, applications of interfacial engineering in 2D systems, and finally a perspective on the future of this rapidly advancing field of study.