Light Extraction Enhancement of GaN LEDs by Hybrid ZnO Micro-Cylinders and Nanorods Array

Author

Zhengmao Yin ; Xiaoyan Liu ; Hanchao Yao ; Yongzhong Wu ; Xiaopeng Hao ; Min Han ; Xiangang Xu

Author_Institution

State Key Lab. of Crystal Mater., Shandong Univ., Jinan, China

Volume

25

Issue

20

fYear

2013

fDate

Oct.15, 2013

Firstpage

1989

Lastpage

1992

Abstract

A hybrid patterned ZnO micro-cylinders and nanorods array (MCNR) was fabricated to improve the light extraction efficiency for high brightness GaN-based light-emitting diodes (LEDs). The light extraction efficiency of the LEDs with the ZnO MCNR is increased by 86.4% compared with conventional planar LEDs. LEDs with ZnO MCNR have greater light extraction efficiency than those only with ZnO micro-cylinders or ZnO nanorods array. The optical-electrical characteristics and far-field radiation patterns are measured and analyzed. The local optical field distribution patterns of the LEDs with ZnO micro-cylinders, ZnO nanorods, and ZnO MCNR are investigated using confocal scanning electroluminescence microscopy. The higher light extraction enhancement effect of ZnO MCNR is attributed to that it combines the light outputting effect from side walls of ZnO micro-cylinders and the light scattering effect of ZnO nanorods array.

Keywords

II-VI semiconductors; III-V semiconductors; brightness; electroluminescence; gallium compounds; light emitting diodes; light scattering; micro-optics; nanophotonics; nanorods; wide band gap semiconductors; zinc compounds; GaN-ZnO; brightness; confocal scanning electroluminescence microscopy; far-field radiation pattern; gallium nitride LED; hybrid zinc oxide microcylinders; light emitting diodes; light extraction enhancement; light outputting effect; light scattering effect; local optical field distribution patterns; nanorod array; optical-electrical characteristics; Arrays; Gallium nitride; Light emitting diodes; Optical imaging; Optical reflection; Optical scattering; Zinc oxide; GaN-based light-emitting diodes (LEDs); light extraction; nanorods array; patterned micro-cylinders; zinc oxide (ZnO);

fLanguage

English

Journal_Title

Photonics Technology Letters, IEEE

Publisher

ieee

ISSN

1041-1135

Type

jour

DOI

10.1109/LPT.2013.2279502

Filename

6584759