Abstract

Uniform spreading of injection current in light-emitting diodes (LEDs) is one of the crucial requirements for better device performances. It is reported that non-uniform current spreading leads to low output power, high current crowding, heating, and reliability degradation of the LED device. This paper reports on the effects of different surface and electrode geometries in the LEDs. To increase the output power of LEDs and reduce the series resistance, a rectangular-type LED (RT-LED) with a centered island cathode has been fabricated and investigated by comparison with a conventional LED (CV-LED). The performances of RT-LEDs were prominently enhanced via uniform current spreading and low current crowding. Performances in terms of increased output power and lower forward voltage of simulated RT-LEDs are much superior to those of CV-LEDs. Based on these results, we investigated the correlation between device geometries and optical characteristics through the fabricated CV and RT-LEDs. The measured output power and forward voltage of the RT-LEDs at 100 mA are 64.7% higher and 8% smaller compared with those of the CV-LEDs.

© 2012 Optical Society of Korea

Improving light extraction of InGaN-based light emitting diodes with a roughened p-GaN surface using CsCl nano-islands

Tongbo Wei, Qingfeng Kong, Junxi Wang, Jing Li, Yiping Zeng, Guohong Wang, Jinmin Li, Yuanxun Liao, and Futing Yi
Opt. Express 19(2) 1065-1071 (2011)

High performance GaN-based flip-chip LEDs with different electrode patterns

Ray-Hua Horng, Shih-Hao Chuang, Ching-Ho Tien, Sin-Cyuan Lin, and Dong-Sing Wuu
Opt. Express 22(S3) A941-A946 (2014)

Effects of current crowding on light extraction efficiency of conventional GaN-based light-emitting diodes

Bin Cao, Shuiming Li, Run Hu, Shengjun Zhou, Yi Sun, Zhiying Gan, and Sheng Liu
Opt. Express 21(21) 25381-25388 (2013)

Design and fabrication of vertical-injection GaN-based light-emitting diodes

Hyunsoo Kim, Kyoung-Kook Kim, Sung-Nam Lee, and Kwang-Hyeon Baik
Opt. Express 19(S4) A937-A942 (2011)

Improved InGaN/GaN light-emitting diodes with a p-GaN/n-GaN/p-GaN/n-GaN/p-GaN current-spreading layer

Zi-Hui Zhang, Swee Tiam Tan, Wei Liu, Zhengang Ju, Ke Zheng, Zabu Kyaw, Yun Ji, Namig Hasanov, Xiao Wei Sun, and Hilmi Volkan Demir
Opt. Express 21(4) 4958-4969 (2013)