Cavity-Enhanced Single-Photon Emission from a Single Impurity-Bound Exciton in ZnSe

Impurity-bound excitons in ZnSe quantum wells are bright single-photon emitters─a crucial element in photonics-based quantum technology. However, to achieve the efficiencies required for practical applications, these emitters must be integrated into optical cavities that enhance their radiative properties and far-field emission patterns. In this work, we demonstrate cavity-enhanced emission from a single impurity-bound exciton in a ZnSe quantum well. We utilize a bullseye cavity structure optimized to feature a small mode volume and a nearly Gaussian far-field transverse mode that can efficiently couple to an optical fiber. The fabricated device displays emission that is more than an order of magnitude brighter than bulk impurity-bound exciton emitters in the ZnSe quantum well, as well as clear antibunching, which verifies the single-photon emission from the source. Time-resolved photoluminescence spectroscopy reveals a Purcell-enhanced radiative decay process with a Purcell factor of 1.43. This work paves the way toward high-efficiency spin-photon interfaces using an impurity-doped II–VI semiconductor coupled to nanophotonics.