Angle-tuned, evanescently-decoupled reflector for high-efficiency red light-emitting diode

We propose and demonstrate evanescently-decoupled, solid-angle-optimized distributed Bragg reflectors (DBRs) for AlGaInP light-emitting diodes (LEDs). The thickness of each DBR layer is tuned to the wavelength slightly longer than the emission peak of the active medium in order to maximize the radia...

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Bibliographic Details
Published in:Optics express 2008-04, Vol.16 (9), p.6026-6032
Main Authors: Kim, Sun-Kyung, Cho, Hyun Kyong, Park, Kyung Keun, Jang, Junho, Lee, Jeong Soo, Park, Kyung Wook, Park, Youngho, Kim, Ju-Young, Lee, Yong-Hee
Format: Article
Language:English
Subjects:
Light
Microscopy, Electron, Scanning
Microscopy, Electron, Transmission
Photons
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Summary:We propose and demonstrate evanescently-decoupled, solid-angle-optimized distributed Bragg reflectors (DBRs) for AlGaInP light-emitting diodes (LEDs). The thickness of each DBR layer is tuned to the wavelength slightly longer than the emission peak of the active medium in order to maximize the radiated power integrated over the top surface. In addition, to increase the horizontal radiation through the side facets, the glancing-angle reflectivity at the AlInP/AlAs interface is improved by employing an AlAs layer thicker than the attenuation length of the evanescent field. With the improved DBR, the integrated output power of AlGaInP LEDs is enhanced by a factor of 1.9 in comparison to those of LEDs with conventional DBRs. Additional 1.25-fold enhancement is observed by incorporating an square-lattice hole array (a=1200nm) into the top GaP surface by a conventional photolithography.
ISSN:1094-4087
1094-4087
DOI:10.1364/OE.16.006026