Single photon generation from AlGaN exciton localization centers exhibiting narrow spectral linewidths

We report the discovery and characterization of single-photon-emitting carrier localization centers that are spontaneously formed along misfit dislocations in AlGaN. The emitters exhibit extremely narrow linewidths, which are in some cases narrower than our resolution limit of 35 µeV. Spectral analysis reveals a record-low inhomogeneous broadening (smaller than 20 µeV), which can be characterized as almost spectral-diffusion free. Such narrow linewidths allow for an unprecedented discussion of the homogeneous linewidths of quantum emitters in the III-nitrides and, in the current case, provide a lower bound on the pure-dephasing time T2 of ∼200 ps. These experimental results will pave the way to further improve the performance of III-nitride low-dimensional nanostructure-based quantum emitters.