GaN as a Material Platform for Single‐Photon Emitters: Insights from Ab Initio Study

Abstract GaN with atom defects is a rising material platform for single‐photon emitter (SPE) recently due to their room‐temperature working conditions, high emission rate, narrow emission line‐width and mature processing technology. However, the SPE mechanism still remains unclear to date, which greatly hinders the progress of GaN based SPE. Herein, systematic ab initio calculations predict and identify two kinds of intrinsic point defects N_Ga and N_GaV_N in GaN, which can be response for the widely observed SPEs. The formation energy, band structure, transition mechanism, and orbital composition are systematically investigated. The results indicate that N_GaV_N° possesses a large zero‐phonon line (ZPL) of 1.98 eV and a short lifetime of 3.56 ns, which may be one of the most possible origins of SPEs in visible wavelengths. The calculation results coincide well with our measured ZPL (1.92 eV) and lifetime (1.14 ns), as well as the experimental results reported previously. This work also predicts that N_Ga⁰ and N_GaV_N⁺¹ can produce SPEs at fiber telecommunications band (0.84 and 0.94 eV, respectively). These results give deep insights into the SPE emission mechanism in GaN and bridge the gap between the realized SPEs and the underlying physical mechanism.