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微结构金属光栅可用于增强LED的发光效率,应用不同的金属材料则表现出不同的光谱辐射特性,使得不同金属材料的微结构光栅对同一波长的光提取效率不同.基于时域有限差分(FDTD)法,计算了在LED芯片内应用不同金属材料的微结构光栅时,LED的光提取增强特性.通过分析金属材料的介电特性和产生表面等离子(SPs)效应的品质因子,发现带内跃迁等离子频率越高的金属材料,由于其自由电子数多,越接近于完全导体,因此越适合于相对波长较短的光子提取.同时发现由散射原因引起的光提取效率增强,对于不同金属材料,其增强因子随波长的变化而变化,并且变化趋势是一致的.而对于由SPs效应引起的增强因子变化,无论是峰值的位置还是大小,都随着材料的不同而发生显著变化.
Microstructured metal gratings can be used to enhance the luminous efficiency of LEDs, and different metal materials exhibit different spectral radiance characteristics, so that the microstructured gratings with different metallic materials have different light extraction efficiencies at the same wavelength.Based on finite difference time-domain (FDTD ) Method, the LED light extraction enhancement property is calculated when the microstructured gratings with different metallic materials are used in the LED chip.By analyzing the dielectric properties of metal materials and the quality factor of the surface plasmon (SPs) effect, it is found that the band transition Due to the large number of free electrons, the closer to the perfect conductor, the more suitable for the extraction of photons with shorter relative wavelength.At the same time, it is found that the light extraction efficiency is enhanced due to scattering, and for different metal materials, The enhancement factor varies with wavelength, and the trend is the same, while for the change of enhancement factor caused by SPs, both the position and the size of the peak change significantly with different materials.