AI 中文总结
该研究针对GaN量子发射器光子提取效率低于模拟值的问题，通过插入低温GaN中间层实现了精度60 nm以下的任意深度量子发射器控制，为GaN中腔增强量子发射奠定了关键基础。
AI 中文摘要
明亮的量子发射器是量子通信系统的关键组件，氮化镓（GaN）中的辐射点缺陷是极具潜力的室温单光子发射候选材料，其工作波段覆盖可见光至电信O波段。尽管具有应用潜力，但其在光子结构中的集成仍受限于现有研究，实验测得的光子提取效率远低于模拟预测值。为明确该限制的来源，我们研究了在c平面蓝宝石衬底上生长的GaN外延层中的可见光及近红外量子发射器，这些发射器展现出窄线宽（约4 nm）、高光子计数率（>2 MHz）和强反聚束特性，室温下g⁽²⁾(0)值低至0.06。我们发现这些发射器位于GaN/衬底界面附近，这解释了其与光学模式耦合有限的问题。基于该发现，我们证明插入薄的低温GaN中间层可实现量子发射器在任意深度的形成，精度达60 nm以下，且与衬底无关。人工引入的发射器保留了与天然发射器相当的光学特性，包括窄线宽（约6 nm）、饱和计数率超过1.5 MHz、高德拜-沃勒因子（0.69-0.98）以及强反聚束特性。所得外延层在不到250 nm内完全合并，确保其与GaN基腔制备的兼容性，并能实现发射器在p-i-n二极管结构的本征区域内的定位。这些结果为实现高效的发射器-腔耦合迈出了关键一步，使GaN中腔增强量子发射的实现成为可能。
英文摘要
Bright quantum emitters are key components for quantum communication systems. Radiative point defects in gallium nitride (GaN) are promising candidates for room-temperature single-photon emission, operating from the visible to the telecom O-band. Despite their potential, their integration into photonic structures has remained limited in the literature, with experimental photon extraction efficiencies far below simulated predictions. To identify the origin of this limitation, we investigate visible and near-infrared quantum emitters in GaN epilayers grown on $c$-plane sapphire substrates exhibiting narrow linewidths ($\sim$4 nm), high photon count rates ($ > $2 MHz), and strong antibunching, reaching $g^{(2)}(0)$ values as low as 0.06 at room temperature. We find that these emitters are located near the GaN/substrate interface, explaining their limited coupling to optical modes. Building on this observation, we show that the insertion of a thin low-temperature GaN interlayer enables the formation of quantum emitters at arbitrary depths with sub-60 nm accuracy, independent of the substrate. The intentionally introduced emitters retain optical properties comparable to naturally occurring ones, including narrow linewidths ($\sim$6 nm), saturation count rates exceeding 1.5 MHz, high Debye-Waller factors (0.69-0.98), and strong antibunching. The resulting epilayer fully coalesces within less than 250 nm ensuring compatibility with GaN-based cavity fabrication and enabling emitter placement within intrinsic regions of p-i-n diode architectures. These results mark a decisive step toward efficient emitter-cavity coupling, enabling the realization of cavity-enhanced quantum emission in GaN.
Comments33 pages, 10 figures
