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, Wei Chih Lai

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


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 Al0.27Ga 0.83N/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.

Original languageEnglish
Pages (from-to)12719-12726
Number of pages8
JournalOptics Express
Issue number13
Publication statusPublished - 2011 Jun 20

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics


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