基于三角光栅的表面等离激元增强型发光二极管

Surface Plasmon Enhanced Light Emitting Diodes Based on Triangular Grating

为了能够同时提高GaN发光二极管(light emitting diode,LED)的光提取效率和内量子效率,将GaN LED与准对称光波导(包含光栅、Ag薄层和SiO2层)集成,并基于时域有限差分法对该结构的GaN LED进行了优化与分析。经模拟计算发现,有源区发出的光在Ag薄层激发了表面等离激元,且表面等离激元与有源区产生了珀塞尔效应,因此显著提高了内量子效率。另外,高透射光栅使得LED的光提取效率得到显著提高,且光栅层使得Ag薄层两侧处形成了折射率准对称的波导结构,这进一步提高了表面等离激元的光提取效率,且Ag薄层两侧的电场呈均匀分布。

In order to simultaneously improve the light extraction efficiency and internal quantum efficiency of Ga N light emitting diodes(LEDs),Ga N LEDs are integrated with quasi-symmetric optical waveguide(including grating,Ag thin layer and SiO2 layer)and the Ga N LED structure is optimized and analyzed based on the finite difference time domain(FDTD)method. The simulation results show that the surface plasma polaritons are excited by the light emitted from the active region in the Ag thin layer which produces the Purcell effect with the active region and thus the internal quantum efficiency is significantly improved. In addition,the existence of the high transmission grating makes the light extraction efficiency of LED significantly improved. Moreover,with the grating layer,the refractive index quasi-symmetrical waveguide structure is formed on both sides of the Ag thin layer,which further improves the light extraction efficiency of surface plasma polaritons and makes the uniform electric field distribution on both sides of the Ag thin layer.