Activated Single Photon Emitters And Enhanced Deep‐Level Emissions in Hexagonal Boron Nitride Strain Crystal

Abstract

The peculiar defect‐related photon emission processes in 2D hexagonal boron nitride (hBN) have become a topic of intense research due to their potential applications in quantum information and sensing technologies. Here, it is reported on exotic single photons and enhanced deep‐level emissions in 2D hBN strain crystal, which is fabricated by transferring multilayer hBN onto hexagonal close‐packed silica spheres on a silica substrate. Effective activation of single photon emission is realized from the defect ensembles in the multilayer hBN at positions that are in contact with the apex of the SiO2 spheres. At these points, the local tensile strain‐induced overall blue shift of the SPE ensembles is up to 12 nm. Furthermore, high spatial resolution cathodoluminescence measurements show remarkable strain‐enhanced deep‐level emissions in the multilayer hBN with the emission intensity distribution following the periodic hexagonal pattern of the strain crystal. The maximum deep‐level emission enhancement is up to 350% with an energy redshift of 6 nm. These results provide a simple on‐chip compatible method for activating and tuning the defect‐related photon emissions in multilayer hBN, demonstrating the potential of hBN strain crystal as a building block for future on‐chip quantum nanophotonic devices.