Deciphering the photophysical properties of near-infrared quantum emitters in AlGaN films by transition dynamics

Point defects in wide bandgap III-nitride semiconductors have been recently reported to be one kind of the most promising near-infrared (NIR) quantum emitters operating at room temperature (RT). But the identification of the point defect species and the energy level structures as well as the transition dynamics remain unclear. Here, the photophysical properties of single-photon emission from point defects in AlGaN films are investigated in detail. According to the first-principles calculations, a three-level model was established to explain the transition dynamics of the quantum emitters. An anti-site nitrogen vacancy complex (V_NN_Ga) was demonstrated to be the most likely origin of the measured emitter since the calculated zero-phonon line (ZPL) and the lifetime of V_NN_Ga in the AlGaN film coincide well with the experimental results. Our results provide new insights into the optical properties and energy level structures of quantum emission from point defects in AlGaN films at RT and establish the foundation for future AlGaN-based on-chip quantum technologies.