Azimuthally isotropic irradiance of GaN-based light-emitting diodes with GaN microlens arrays.
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.
Department of Optics and Photonics, National Central University, Jhongli, Taiwan 32054, ROC. mlwu@dop.ncu.edu.tw
Mount-Learn
ML
Wu
Yun-Chih
YC
Lee
Shih-Pu
SP
Yang
Po-Shen
PS
Lee
Jenq-Yang
JY
Chang
D016880:Anisotropy; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry*; D007909:Lenses; D008029:Lighting / Q000295:instrumentation*; D008904:Miniaturization; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012666:Semiconductors; D012680:Sensitivity and Specificity
C473348:gallium nitride; D005708:Gallium