Wafer-scale vertical van der Waals heterostructures

Wafer-scale van der Waals heterostructures (vdWHs), benefitting from the rich diversity in materials available and stacking geometry, precise controllability in devices structure and performance, and unprecedented potential in practical application, have attracted considerable attention in the field of two-dimensional (2D) materials. This article reviews the state-of-the-art research activities that focus on wafer-scale vdWHs and their (opto)electronic applications. We begin with the preparation strategies of vdWHs with wafer size and illustrate them from four key aspects, that is, mechanical-assembly stack, successive deposition, synchronous evolution, and seeded growth. We discuss the fundamental principle, underlying mechanism, advantages, and disadvantages for each strategy. We will then review the applications of large-area vdWHs based devices in electronic, optoelectronic and flexible devices field, unveiling their promising potential for practical application. Ultimately, we will demonstrate the challenges they face and provide some viable solutions on wafer-scale heterostructure synthesis and device fabrication.