Effect of surface texture and backside patterned reflector on the AlGaInP light-emitting diode: High extraction of waveguided light

Ya Ju Lee, Chia Jung Lee, Chih Hao Chen

Research output: Contribution to journalArticle

20 Citations (Scopus)


This paper describes a novel structure of an AlGaInP light-emitting diode (LED) to extract the waveguided light for high-brightness applications. Four devices are considered and compared. They are AlGaInP-sapphire LEDs with: 1) a planar Ag reflector (LED-A); 2) a patterned Ag reflector (LED-B); 3) a planar Ag reflector and surface-roughened features (LED-C); and 4) a patterned Ag reflector and surface-roughened features (LED-D). The patterned Ag reflector can be used to direct some of the waveguided light that bounces within the AlGaInP LED and sapphire substrate to the top escape cone of the LED surface. Additionally, the roughened features, which are randomly distributed on the LED surface, enable the waveguided light that is trapped inside the LED chip to be coupled efficiently into the air. As a result, the external quantum efficiencies of LED-A, LED-B, LED-C, and LED-D measured at I=350 mA are η=9.20%, 10.46%, 15.22%, and 16.75%, respectively.

Original languageEnglish
Article number5738955
Pages (from-to)636-641
Number of pages6
JournalIEEE Journal of Quantum Electronics
Issue number5
Publication statusPublished - 2011 Apr 4



  • AlGaInP
  • light emitting diode
  • waveguided light

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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