The defect-based single-photon emitters (SPEs) in gallium nitride (GaN) have attracted considerable research interest due to their high emission rate, narrow line width, and room-temperature operation. However, the quenching effect greatly restricts the applications of these SPEs, and the origin of the quenching mechanism is still unclear. Here, based on systematic ab initio calculations, we reveal a possible quenching mechanism originating from the transformation between two different structures of the defect-pair N_GaV_N in wurtzite GaN. Our results indicate that the defect-pair N_GaV_N possesses two stable detect-structures A and B, where the structure B has a small zero phonon line (ZPL) and long lifetime. The transformation barrier from structures A to B is only 0.097 eV. Thus, structure A can easily transform to structure B under laser illumination due to thermal fluctuations, causing a quenching phenomenon. Our work also predicts that the barrier energy between defect structures A and B could be effectively adjusted through tuning the triaxial compressive strain of the crystal structure. This provides an effective method to suppress the quenching effect of defect-pair N_GaV_N in GaN, paving the way for practical applications of SPEs.

中文翻译：

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GaN点缺陷单光子发射极的淬灭机理及抑制方法

氮化镓（GaN）中基于缺陷的单光子发射器（SPE）由于其高发射率、窄线宽和室温操作而引起了广泛的研究兴趣。然而，猝灭效应极大地限制了这些SPE的应用，并且猝灭机制的起源仍不清楚。在这里，基于系统的从头计算，我们揭示了一种可能的猝灭机制，该机制源于纤锌矿GaN中缺陷对N _Ga V _N的两种不同结构之间的转变。我们的结果表明，缺陷对 N _Ga V _N具有两个稳定的检测结构 A 和 B，其中结构 B 具有较小的零声子线（ZPL）和较长的寿命。从结构A到B的转变势垒仅为0.097 eV。因此，结构A在激光照射下很容易因热波动而转变为结构B，从而引起淬火现象。我们的工作还预测，通过调整晶体结构的三轴压应变，可以有效地调整缺陷结构 A 和 B 之间的势垒能。这提供了一种有效的方法来抑制GaN中缺陷对N _Ga V _N的猝灭效应，为SPE的实际应用铺平了道路。