Herein, the temperature dependent emission properties of defect‐based single photon emitters (SPEs) in GaN, with a focus on the possible interaction between phonons and electrons are investigated. Using 2D mapping and time‐correlated single photon counting measurements at both room temperature and cryogenic conditions, the spatial distribution, emission spectra, and second‐order correlation functions (g 2 ( τ )) of the SPEs are characterized. At cryogenic temperatures (4–100 K), a marked reduction in the full‐width at half maximum and a shift in the emission peak are observed, which are consistent with the suppression of phonon coupling at lower temperatures. An analysis of phonon interactions with both SPEs and free‐exciton photoluminescence reveals a weaker temperature dependence of the emission energy in SPEs compared to band‐to‐band transitions. This behavior is attributed to reduced anharmonic phonon interactions in SPE transitions relative to those involving electrons in the conduction and valence bands. The zero‐phonon line exhibits line broadening in the cryogenic temperature range, primarily due to interactions with acoustic phonons. Acoustic phonon interaction coefficients for representative SPEs are 2.8 μeV K −1 and 6.6 μeV K −1 , which are comparable but slightly larger than values reported for InAs and CdSe quantum dots.
Choi et al. (Tue,) studied this question.