Improved light extraction efficiency in AlGaInP light-emitting diodes by applying a periodic texture on the surface

Liang Jyi Yan, Jinn-Kong Sheu, Wei Chih Wen, Tien Fu Liao, Ming Jong Tsai, Chih Sung Chang

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

In this letter, AlGaInP-GaP-based light-emitting diodes (LEDs) were fabricated with an Si substrate and an SiO2-ITO-Ag omni-directional reflector using a metal-to-metal bonding technique. To enhance light extraction efficiency, a periodic texture was applied to the (Al0.5Ga0.5)0.5In0.5P surface layer of AlGaInP-Si LEDs by photolithography and a wet etching process. The exterior of the etched texture consists of a series of bowl-shaped recesses. With a 350-mA current injection, the typical output power of the AlGaInP-Si LEDs with and without the textured surface (LED-I and LED-II, respectively) were measured at approximately 118 and 81 mW, respectively, when the LED chips were bonded on the TO 46 without resin encapsulation. The enhancement of output power in LED-I can be attributed to a multitude of bowl-shaped notches on the surface, which resulted in a reduction of the reabsorption probability of the photons due to the fact that the photon path length in LED-I is shorter than in LED-II before the photons escape into the free space.

Original languageEnglish
Pages (from-to)1724-1726
Number of pages3
JournalIEEE Photonics Technology Letters
Volume20
Issue number20
DOIs
Publication statusPublished - 2008 Oct 15

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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