Identifying carbon as the source of visible single-photon emission from hexagonal boron nitride

Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) have garnered increasing attention over the last few years due to their superior optical properties. However, despite the vast range of experimental results and theoretical calculations, the defect structure responsible for the observed emission has remained elusive. Here, by controlling the incorporation of impurities into hBN via various bottom-up synthesis methods and directly through ion implantation, we provide direct evidence that the visible SPEs are carbon related. Room-temperature optically detected magnetic resonance is demonstrated on ensembles of these defects. We perform ion-implantation experiments and confirm that only carbon implantation creates SPEs in the visible spectral range. Computational analysis of the simplest 12 carbon-containing defect species suggest the negatively charged VBCN- defect as a viable candidate and predict that out-of-plane deformations make the defect environmentally sensitive. Our results resolve a long-standing debate about the origin of single emitters at the visible range in hBN and will be key to the deterministic engineering of these defects for quantum photonic devices.

Automated summary

The visible single-photon emitters in hexagonal boron nitride have been confirmed to be carbon-related, based on evidence from controlling impurity incorporation and conducting implantation experiments. Computational analysis identified the negatively charged VBCN- defect as a likely candidate, with predictions of its environmental sensitivity. This resolves the long-standing debate on the origin of single emitters in hBN and will be crucial for the deterministic engineering of these defects for quantum photonic devices.