Quantum Emitters in Flux Grown hBN

Hexagonal boron nitride (hBN) is an emerging material for use in quantum technologies, hosting bright and stable single photon emitters (SPEs). The B-center is one promising SPE in hBN, due to the near-deterministic creation methods and regular emission wavelength. However, incorporation of B-centers in high-quality crystals remains challenging, typically relying on additional postgrowth methods to increase creation efficiency. Here, we have demonstrated controlled carbon doping of hBN during growth, using a metal flux-based method to increase the efficiency of B-center creation. Importantly, single B-centers with g(2)(0) < 0.5 were able to be generated in the as-grown hBN when carbon additions during growth exceeded 2.5 wt % C. Resonant excitation measurements revealed line widths of 3.5 GHz with only moderate spectral diffusion present, demonstrating the applicability of the as-grown hBN as a host for high-quality B-centers.