Near-Infrared Single-Photon Emission from Oxygen-Related Defects in hBN

Color centers in hexagonal boron nitride (hBN) are a promising platform for quantum light sources and spin–photon interfaces. As a wide-bandgap (~6 eV) van der Waals semiconductor, hBN hosts diverse defects emitting from the UV to the NIR. Here we demonstrate a simple, scalable oxygen-plasma process that reproducibly creates bright, stable oxygen-related single-photon emitters. Hyperspectral confocal maps of >200 sites show blinking-free zero-phonon lines across 700–960 nm, robust room-temperature operation, and ultrasharp cryogenic linewidths down to ~11.1 μeV (~2.7 GHz) under quasi-resonant excitation. At 4 K, the emitters reach ~1 MHz count rates, ~1 ns radiative lifetimes, and high Debye–Waller factors. Polarization-resolved spectra reveal high emission and absorption dipole visibility. The weak phonon sidebands imply high internal quantum efficiency. Integrated into vdW heterostructures and tuned via electrostatic gating or nanophotonic cavities, these defects provide a path to indistinguishable photons, spin–optical interfaces, and free-space NIR quantum links.