Gallium nitride-based light-emitting diodes with embedded air voids grown on Ar-implanted AlN/sapphire substrate

GaN-based light-emitting diodes (LEDs) grown on sapphire with ex situ AlN nucleation layer prepared by radio-frequency sputtering were investigated. GaN-based epitaxial layers grown on the Ar-implanted AlN/sapphire (AIAS) substrates exhibited selective growth and subsequent lateral growth due to the...

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Bibliographic Details
Published in:Applied physics letters 2012-10, Vol.101 (15)
Main Authors: Sheu, Jinn-Kong, Tu, Shang-Ju, Yeh, Yu-Hsiang, Lee, Ming-Lun, Lai, Wei-Chih
Format: Article
Language:English
Subjects:
Aluminum nitride
Current injection
Gallium nitrides
Lattice parameters
Light-emitting diodes
Nucleation
Sapphire
Voids
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Summary:GaN-based light-emitting diodes (LEDs) grown on sapphire with ex situ AlN nucleation layer prepared by radio-frequency sputtering were investigated. GaN-based epitaxial layers grown on the Ar-implanted AlN/sapphire (AIAS) substrates exhibited selective growth and subsequent lateral growth due to the difference of lattice constants between the implanted and implantation-free regions. Consequently, air voids over the implanted regions were formed around the GaN/AlN/sapphire interfaces. We proposed the growth mechanisms of the GaN layer on the AIAS substrates and characterized the LEDs with embedded air voids. With a 20 mA current injection, experimental results indicate that the light output power of LEDs grown on the AIAS substrates was enhanced by 25% compared with those of conventional LEDs. This enhancement can be attributed to the light scattering at the GaN/air void interfaces to increase the light extraction efficiency of the LEDs.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4757996