Single Photon Emission from Zero-Dimensional Boron Nitride Nano-Structures*

Bright, robust hosts of quantum emitters are necessary for the development of integrated quantum information technologies and metrology. Quantum emitters in 2D hexagonal boron nitride (hBN) exhibit promise for photonic integration with bright fluorescence and room-temperature stability. However, they are susceptible to strain – causing unwanted wavelength shifts. We find a bright single photon emitter in boron nitride nano-cocoons (BNNC) - a boron nitride nano-allotrope that overcomes strain susceptibility through structural robustness. We optically characterize our quantum emitters and find extensive similarities to the SPEs found in other hBN allotropes. The photoluminescence intensity can be up to 100 kcps at 1 mW, the lifetime ranges from 1-10 ns, and the distance between the zero-phonon line to phonon sideband is 133 meV. We find the emission varies across 27 nm compared to the 200 nm seen in 2D hBN. This range is more similar to SPEs in bulk hBN, corroborating our idea of structural robustness. We identify the host material through cross-correlated confocal optical microscopy and transmission electron microscopy. This robust nano-allotrope of BN offers an ideal host of SPEs for use in hybrid photonic technologies, quantum metrology, and biolabeling.