It is usually believed that surface plasmon (SP) coupling is practically useful only for improving the performance of a light-emitting diode (LED) with a low intrinsic internal quantum efficiency (IQE). In this Letter, we demonstrate that the performance of a commercial-quality blue LED with a high IQE ($>80\%$) can still be significantly improved through SP coupling based on a surface Ag nanoparticle (NP) structure. The performance improvement of such an LED is achieved by increasing the Mg doping concentration in its $p$-AlGaN electron blocking layer to enhance the hole injection efficiency such that the $p$-GaN layer thickness can be significantly reduced without sacrificing its electrical property. In this situation, the distance between surface Ag NPs and quantum wells is decreased and hence SP coupling strength is increased. By reducing the distance between the surface Ag NPs and the top quantum well to 66 nm, the IQE can be increased to almost 90% (an $\sim 11\%$ enhancement) and the electroluminescence intensity can be enhanced by $\sim 24\%$.

中文翻译：

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通过表面等离子体激元耦合进一步提高商业品质的发光二极管的发射效率

通常认为，表面等离子体激元（SP）耦合实际上仅用于改善具有低固有内部量子效率（IQE）的发光二极管（LED）的性能。在这封信中，我们证明了具有高IQE（$>80％$仍然可以通过基于表面银纳米粒子（NP）结构的SP偶联显着改善。这种LED的性能改进是通过增加其Mg的掺杂浓度来实现的$p$-AlGaN电子阻挡层可提高空穴注入效率，从而使 $p$-GaN层的厚度可以在不牺牲其电性能的情况下显着减小。在这种情况下，表面Ag NP与量子阱之间的距离减小，因此SP耦合强度增加。通过将表面Ag NP与顶部量子阱之间的距离减小到66 nm，IQE可以提高到几乎90％（$〜11％$ 增强）和电致发光强度可以通过 $〜24％$。