以中心波长为650 nm的氮化镓LED外延片为研究对象，提出了一种反射式表面等离激元增强型LED来提高其发光效率。该结构包含依次覆盖在正弦起伏的p型GaN层上的一层低折射率的SiO2膜与一层Ag膜。银膜用来增强内量子效率，而SiO2层能进一步提高GaN层上表面的反射率，同时通过优化蓝宝石衬底的厚度使得GaN层下方的透射率较高，从而得到了较大的发光效率。

We investigate the GaN-LED epitaxial wafers whose central wavelength is 650 nm and propose a kind of bottom-emitting surface-plasmon-enhanced LED to improve its emission efficiency. This LED includes a SiO2 layer of low refractive index and a silver film coated on the sinusoidal wavy-patterned p-GaN layer in sequence. The Ag film is used to enhance the internal quantum efficiency and the SiO2 layer is employed to further improve the reflectivity of the upper surface of GaN-layer. And the transmissivity through the sapphire substrate whose thickness is optimized is very high. The emission efficiency of this structure is raised greatly.