Son Jun Ho, Yu Hak Ki, Lee Jong-Lam
Department of Materials Science and Engineering, Pohang University of Science and Technology, Gyeongbuk, Korea.
Opt Express. 2010 Sep 13;18 Suppl 3:A403-10. doi: 10.1364/OE.18.00A403.
We demonstrate novel method for improving light extraction efficiency for n-side-up vertical InGaN/GaN light-emitting diodes (V-LEDs) using MgO nano-pyramids and ZnO refractive-index modulation layer. The MgO nano-pyramids structure is successfully fabricated on n-GaN/ZnO surface using electron-beam evaporation. The light output power of n-GaN/ZnO/MgO V-LEDs is enhanced by 49% compare to that of n-GaN V-LEDs. The angular-dependent far-field emission shows the significant increase of side emission for the n-GaN/ZnO/MgO V-LEDs due to the increase of critical angle for total internal reflection as well as the roughened surface by MgO pyramids structure. These experimental results indicate the critical role of surface texturing in improving the light extraction efficiency of the V-LEDs for solid-state lighting.
我们展示了一种新颖的方法，即使用MgO纳米金字塔和ZnO折射率调制层来提高n面朝上垂直InGaN/GaN发光二极管（V-LED）的光提取效率。利用电子束蒸发在n-GaN/ZnO表面成功制备了MgO纳米金字塔结构。与n-GaN V-LED相比，n-GaN/ZnO/MgO V-LED的光输出功率提高了49%。角度相关的远场发射表明，由于全内反射临界角的增加以及MgO金字塔结构使表面粗糙化，n-GaN/ZnO/MgO V-LED的侧向发射显著增加。这些实验结果表明表面纹理化在提高用于固态照明的V-LED的光提取效率方面起着关键作用。
