利用光子晶体提高InP基LED出光效率

Enhancement of Light Extraction of LED by Photonic Crystal Structures

应用FDTD方法计算了二维无限大光子晶体的能带结构,并制备出了InP基二维平板结构的光子晶体器件.在制备过程中尝试了仅用PMMA做掩模以及PMMA和SiO2做掩模两种方法.结果表明,不使用SiO2做掩模的情况下,由于PMMA胶选择性较差,在刻蚀过程中难以保证图形的准确转移.而增加SiO2掩模后,获得了图形质量良好的光子晶体结构.成功实现了利用光子晶体结构增强LED的出光效率,与未制作光子晶体结构的LED相比,光子晶体结构LED的出光效率可在原来基础上提高1倍以上.并且随着晶格常数的增加,出光效率进一步提高.

The band structure of a 2D infinite photonic crystal is calculated using the FDTD method. Slab photonic crystals with InP are fabricated. Two fabrication methods one using only PMMA as mask and one using PMMA and SiO2 as masks are used. The results show that the first method cannot yield an accurate pattern transfer, while the other method can. The extraction efficiency in an LED is enhanced successfully by use of the photonic crystal. The light extraction efficiency of the LED with the photonic crystal structure is twice as high as that of the unprocessed sample under the same testing conditions. Along with the increase of lattice constant, the extraction efficiency also increases.