Epitaxial van der Waals semiconductor superlattices

Abstract

We report epitaxial stacking growth of van der Waals (vdW) semiconductor superlattices (SLs), composed of MoS2 and WS2 monolayers (MLs), by metalorganic chemical vapor depositions. The stacking sequence of constituent MLs was precisely controlled by atomic-layer epitaxy, enabling to achieve the tunable two-dimensional (2D) vdW electronic structures, whose properties are markedly different from covalent semiconductor SLs, such as a prominent example of GaAs-AlGaAs. We also present distinctive optical and electronic properties that only pertain to this epitaxially-defined 2D vdW electronic structure in ML resolutions.