Fabrication of Single-Photon Emitters in 2D Hexagonal Boron Nitride via Carbon Annealing

As the most recent addition to the single-photon emitter library, defects in hexagonal boron nitride (hBN) have attracted much attention due to their high brightness at room temperature and stability. These emitters also have the potential to integrate with cavities and photonic waveguides thanks to their 2D hosting system. Here, we developed a new method to activate single-photon emitters in 2D hBN, which is highly desired for their further application. We annealed mechanically exfoliated hBN under mixed atmosphere with methane as carbon source, and our simple one-step annealing process yields a tremendous increase in the concentration of emitters in hBN. With several related experiments, the single defects fabricated by our method are confirmed to be quantum emitters. Some other photophysical properties indicate that the emitters show higher brightness and become more stable after carbon annealing. Our approach to the design of single photon emitters in 2D hBN opens up new avenues for the generation of single photon emitters and their integration in quantum nanophotonic devices.