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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 13 — Jun. 20, 2011
  • pp: 12719–12726

Enhanced output power of GaN-based LEDs with embedded AlGaN pyramidal shells

Shang-Ju Tu, Jinn-Kong Sheu, Ming-Lun Lee, Chih-Ciao Yang, Kuo-Hua Chang, Yu-Hsiang Yeh, Feng-Wen Huang, and Wei-Chih Lai  »View Author Affiliations

Optics Express, Vol. 19, Issue 13, pp. 12719-12726 (2011)

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In this article, the characteristics of GaN-based LEDs grown on Ar-implanted GaN templates to form inverted Al0.27Ga0.83N pyramidal shells beneath an active layer were investigated. GaN-based epitaxial layers grown on the selective Ar-implanted regions had lower growth rates compared with those grown on the implantation-free regions. This resulted in selective growth, and formation of V-shaped concaves in the epitaxial layers. Accordingly, the inverted Al0.27Ga0.83N pyramidal shells were formed after the Al0.27Ga0.83N and GaN layers were subsequently grown on the V-shaped concaves. The experimental results indicate that the light-output power of LEDs with inverted AlGaN pyramidal shells was higher than those of conventional LEDs. With a 20 mA current injection, the output power was enhanced by 10% when the LEDs were embedded with inverted Al0.27Ga0.83N pyramidal shells. The enhancement in output power was primarily due to the light scattering at the Al0.27Ga0.83N/GaN interface, which leads to a higher escape probability for the photons, that is, light-extraction efficiency. Based on the ray tracing simulation, the output power of LEDs grown on Ar-implanted GaN templates can be enhanced by over 20% compared with the LEDs without the embedded AlGaN pyramidal shells, if the AlGaN layers were replaced by Al0.5Ga0.5N layers.

© 2011 OSA

OCIS Codes
(230.0250) Optical devices : Optoelectronics
(230.3670) Optical devices : Light-emitting diodes
(230.5590) Optical devices : Quantum-well, -wire and -dot devices

ToC Category:
Optical Devices

Original Manuscript: February 16, 2011
Revised Manuscript: June 9, 2011
Manuscript Accepted: June 10, 2011
Published: June 16, 2011

Shang-Ju Tu, Jinn-Kong Sheu, Ming-Lun Lee, Chih-Ciao Yang, Kuo-Hua Chang, Yu-Hsiang Yeh, Feng-Wen Huang, and Wei-Chih Lai, "Enhanced output power of GaN-based LEDs with embedded AlGaN pyramidal shells," Opt. Express 19, 12719-12726 (2011)

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