  Development of stable room-temperature bright single-photon emitters using
atomic defects in hexagonal-boron nitride flakes (h-BN) provides significant
promises for quantum technologies. However, an outstanding challenge in h-BN is
creating site-specific, stable, high emission rate single photon emitters with
very low Huang-Rhys (HR) factor. Here, we discuss the photonic properties of
site-specific, isolated, stable quantum emitter that emit single photons with a
high emission rate and unprecedented low HR value of 0.6 at room temperature.
Scanning confocal image confirms site-specific single photon emitter with a
prominent zero-phonon line at ~578 nm with saturation photon counts of 105
counts/second. The second-order intensity-intensity correlation measurement
shows an anti-bunching dip of ~0.25 with an emission lifetime of 2.46 ns.
Low-energy electron beam irradiation and subsequent annealing are important to
achieve stable single photon emitters.
