Improvement in the extraction efficiency of AlGaInP and GaN thin film LEDs via surface roughening

Y. J. Lee*, Hao-Chung Kuo, Tien-chang Lu, H. W. Huang, S. C. Wang, C. F. Lin

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


In the first part of this paper, we present a LED structure adopting double diffused-surfaces on-top transmitted diffuse surface and another diffuse omnidirectional reflector surface on the bottom of LED chip. According to this design, guided light scattered by bottom diffuse omnidirectional reflectors can be again scattered toward to angles inside the escape cone by top diffuse transmittance surfaces. High light external efficiency (∼ 40%) was achieved on this novel structure. This high efficiency could be attributed to the strong scattering efficiency of using double diffuse surfaces, further reducing trapping of light within LED chips. In the second part, we present n-side-up AlGaInP-based LEDs with a triangle-like surface morphology using the adhesive layer bonding technique, followed by wet etching to roughen the surface. The novel AlGaInP LED design could not only reduce internal reflection between rear mirror systems and the semiconductor/air interface, but also to effectively scatter light outside LED devices. copyright The Electrochemical Society.

Original languageEnglish
Pages (from-to)199-211
Number of pages13
JournalECS Transactions
Issue number5
StatePublished - 1 Dec 2006
EventState-of-the-Art Program on Compound Semiconductors 45 (SOTAPOCS 45) -and- Wide Bandgap Semiconductor Materials and Devices 7 - 210th Electrochemical Society Meeting - Cancun, Mexico
Duration: 29 Oct 20063 Nov 2006


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