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Research Paper

Journal of the Optical Society of Korea 2012; 16(4): 349-353

Published online December 25, 2012 https://doi.org/10.3807/JOSK.2012.16.4.349

Copyright © Optical Society of Korea.

Fabrication and Characterization of a GaN Light-emitting Diode (LED) with a Centered Island Cathode

Yun Soo Park1, Hwan Gi Lee1, Chung-Mo Yang1, Dong-Seok Kim1, Jin-Hyuk Bae1, Seongjae Cho2, Jung-Hee Lee1, and In Man Kang1

1School of Electrical Engineering and Computer Science, Kyungpook National University; 2Department of Electrical Engineering, Stanford University

Received: July 2, 2012; Revised: July 30, 2012; Accepted: August 8, 2012


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.

Keywords: Light-emitting diode, Electrode geometries, Centered island cathode, Output power,

OCIS codes: 080.2740; 160.4670; 220.4610; 230.3670; 350.4600