Wu Mount-Learn, Lee Yun-Chih, Yang Shih-Pu, Lee Po-Shen, Chang Jenq-Yang
Department of Optics and Photonics, National Central University, Jhongli, Taiwan 32054, ROC.
Opt Express. 2009 Apr 13;17(8):6148-55. doi: 10.1364/oe.17.006148.
In this paper, the irradiance-modifying concept is proposed by introducing a microlens array on the p-GaN layer of GaN-based light-emitting diode (LED). Every microlens can locally modulate photons emitting from a micro-scaled active region of multiple quantum wells (MQWs) just beneath the microlens. The azimuthally isotropic irradiance from the GaN-based LED with microlens arrays is demonstrated numerically and experimentally. To realize such a novel LED, one-dimensional GaN microlens array with a period of 1.6 microm and a filling factor of 0.64 are fabricated by using dry etching. According to experimental results, the azimuthally isotropic light emission of proposed LED is observed. By using the angular-resolved photoluminescence, its intensity variation corresponding to the azimuth angles is as low as 10% within the angle region of +/-50 degrees.
在本文中，通过在基于氮化镓（GaN）的发光二极管（LED）的p-GaN层上引入微透镜阵列，提出了辐照度调制概念。每个微透镜都可以局部调制从其下方多量子阱（MQW）的微尺度有源区发射的光子。通过数值和实验证明了具有微透镜阵列的基于GaN的LED的方位角各向同性辐照度。为了实现这种新型LED，采用干法刻蚀制备了周期为1.6微米、填充因子为0.64的一维GaN微透镜阵列。根据实验结果，观察到了所提出LED的方位角各向同性发光。通过角分辨光致发光，在±50度的角度区域内，其对应方位角的强度变化低至10%。
