Photoluminescence imaging of single photon emitters within nanoscale strain profiles in monolayer WSe ₂

Abstract

Local deformation of atomically thin van der Waals materials provides a powerful approach to create site-controlled chip-compatible single-photon emitters (SPEs). However, the microscopic mechanisms underlying the formation of such strain-induced SPEs are still not fully clear, which hinders further efforts in their deterministic integration with nanophotonic structures for developing practical on-chip sources of quantum light. Here we investigate SPEs with single-photon purity up to 98% created in monolayer WSe ₂ via nanoindentation. Using photoluminescence imaging in combination with atomic force microscopy, we locate single-photon emitting sites on a deep sub-wavelength spatial scale and reconstruct the details of the surrounding local strain potential. The obtained results suggest that the origin of the observed single-photon emission is likely related to strain-induced spectral shift of dark excitonic states and their hybridization with localized states of individual defects.

Abstract

Here, the authors correlate the position and spectral emission properties of single photon emitters in monolayer WSe ₂ with the surrounding local strain potential by combining deep-subwavelength photoluminescence imaging and atomic force microscopy, providing insights on the microscopic mechanisms behind the formation of the quantum emitters.