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
(080.2740) Geometric optics : Geometric optical design
(160.4670) Materials : Optical materials
(220.4610) Optical design and fabrication : Optical fabrication
(230.3670) Optical devices : Light-emitting diodes
(350.4600) Other areas of optics : Optical engineering
Original Manuscript: July 2, 2012
Revised Manuscript: July 30, 2012
Manuscript Accepted: August 8, 2012
Published: December 25, 2012
Yun Soo Park, Hwan Gi Lee, Chung-Mo Yang, Dong-Seok Kim, Jin-Hyuk Bae, Seongjae Cho, Jung-Hee Lee, and In Man Kang, "Fabrication and Characterization of a GaN Light-emitting Diode (LED) with a Centered Island Cathode," J. Opt. Soc. Korea 16, 349-353 (2012)
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