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 NGa and NGaVN 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 NGaVN° 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 NGa0 and NGaVN+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.
Point defects in the wide bandgap III-nitride semiconductors are recently reported to be one kind of the most promising near-infrared (NIR) quantum emitters operating at room temperature (RT). But the...
Point defect-based single-photon emitters (SPEs) in GaN have aroused a great deal of interest due to their room-temperature operation, narrow line width and high emission rate. The room-temperature SPEs at the telecommunication bands have also been realized recently by localized defects in GaN in experiments, which are highly desired for the practical applications of SPEs in quantum communication with fiber compatibility. However, the origin and underlying mechanism of the SPEs remain unclear to date. Herein, our first-principle calculations predict and identify an intrinsic point defect NGa in GaN that owns a zero-phonon line (ZPL) at telecommunication windows. By tuning the triaxial compressive strain of the crystal structure, the ZPL of NGa can be modulated from 0.849 eV to 0.984 eV, covering the fiber telecommunication windows from the O band to the E band. Besides the ZPL, the formation energy, band structure, transition process and lifetime of the SPEs under different strains are investigated systematically. Our work gives insight into the emission mechanism of the defect SPEs in GaN and also provides effective guidance for achieving wavelength-tunable SPEs working in fiber telecommunication windows.
Point defect-based single-photon emitters (SPEs) in GaN have aroused a great deal of interest due to their room-temperature operation, narrow line width and high emission rate. The room-temperature SPEs at the telecommunication bands have also been realized recently by localized defects in GaN in experiments, which are highly desired for the practical applications of SPEs in quantum communication with fiber compatibility. However, the origin and underlying mechanism of the SPEs remain unclear to date. Herein, our first-principle calculations predict and identify an intrinsic point defect NGa in GaN that owns a zero-phonon line (ZPL) at telecommunication windows. By tuning the triaxial compressive strain of the crystal structure, the ZPL of NGa can be modulated from 0.849 eV to 0.984 eV, covering the fiber telecommunication windows from the O band to the E band. Besides the ZPL, the formation energy, band structure, transition process and lifetime of the SPEs under different strains are investigated systematically. Our work gives insight into the emission mechanism of the defect SPEs in GaN and also provides effective guidance for achieving wavelength-tunable SPEs working in fiber telecommunication windows.
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