Manipulating Interlayer Excitons for Ultra-pure Near-infrared Quantum Light Generation

Interlayer excitons (IXs) formed at the interface of atomically-thin semiconductors possess various novel properties. In a parallel development, nanoscale strain engineering has emerged as an effective means for creating 2D quantum light sources. Exploring the intersection of these two exciting areas, where strain and defects are exploited for the manipulation of IX toward the emergence of new functionalities, is currently at a nascent stage. Here, using MoS2/WSe2 heterostructure as a model system, we demonstrate how strain, defects, and layering can be utilized to create defect-bound IXs capable of bright, robust, and tunable quantum light emission in the technologically important near-infrared spectral range. We were able to achieve ultra-high single-photon purity with g(2)(0) = 0.01. Our strategy of creating site-controlled QEs from the defect-bound IXs represents a paradigm shift in 2D quantum photonics research, from engineering intralayer exciton in monolayer structures towards IXs at the interface of 2D heterostructures.