基于缺陷光子晶体结构的GaN基发光二极管光提取效率的有关研究

Study on the light extraction efficiency of GaN-based light emitting diode by using the defects of the photonic crystals

现有的研究表明,利用光子晶体可以有效提高发光二极管的光提取效率.由于在制造时光子晶体中可能会存在缺陷和错位,本文基于时域有限差分法对光子晶体中的缺陷和错位对发光二极管发光效率的影响进行了研究.数值仿真结果表明,光子晶体中少量缺陷或者微小错位并不会降低发光二极管的光提取效率,其中某些缺陷反而能增强光子晶体发光二极管的光提取效率.本文对其物理机理给出了详细的理论分析,并设计了一种具有缺陷的光于晶体,在未刻蚀到有源层(离有源层20 nm)的情况下,其光提取效率达到了完美光子晶体的1.6倍.通过对这种缺陷光子晶体的空间频谱分析可知,可以通过设计具有特殊空间频谱分布的光子晶体来提高发光二极管的发光效率,这对设计高光提取效率的光子晶体结构和制造高效率的发光二极管有指导意义.

Many studies have shown that the photonic crystals and surface nanostructures can improve the light extraction efficiency of light emitting diode （LED）. The defects and disorders exist in photonic crystals inevitably as the manufacturing technology limitations, and so the light extraction efficiency of LED will be changed correspondingly. In this work we perform a simulation study on defects and disorder of photonic crystals by the finite-difference time-domain （FDTD） method, and we speed up the FDTD by GPU acceleration technology. Simulation results show that a small number of defects in photonic crystals LED do not reduce the LED light extraction efficiency. Instead, the light extraction efficiency of LED will be increased by adding some defects into the photonic crystals. We give a detailed analysis of its physical mechanism. We design a kind of photonic crystals with defects, and its light extraction efficiency achieves 1.6 times that of the perfect photonic crystals.