Ng W N, Leung C H, Lai P T, Choi H W
Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam road, Hong Kong.
Nanotechnology. 2008 Jun 25;19(25):255302. doi: 10.1088/0957-4484/19/25/255302. Epub 2008 May 14.
Instead of using conventional electron lithography, a two-dimensional photonic crystal consisting of a hexagonal array of triangular air-holes was created on the surface of a GaN LED substrate using microsphere lithography. The microspheres self-assemble into a single-layered hexagonal-close-packed array acting as an etch mask. A significant enhancement in photoluminescence intensity was recorded from the PhC LED structure. A twofold increase in electroluminescence was observed from the PhC LED compared to an as-grown LED with identical geometry. Besides geometrical factors due to surface roughening, the dispersive nature of PhCs and diffractive properties of the PhC as a grating contribute to the enhancement of light extraction from the LED.
通过微球光刻技术，在氮化镓发光二极管（GaN LED）衬底表面制备了由三角形气孔的六边形阵列构成的二维光子晶体，而非使用传统的电子光刻技术。微球自组装成单层六边形紧密堆积阵列，作为蚀刻掩膜。从光子晶体发光二极管（PhC LED）结构记录到光致发光强度显著增强。与具有相同几何结构的生长态LED相比，观察到PhC LED的电致发光增加了两倍。除了表面粗糙度引起的几何因素外，光子晶体的色散特性以及作为光栅的光子晶体的衍射特性有助于提高LED的光提取效率。
