Akademska digitalna zbirka SLovenije - logo
E-resources
Full text
  • Improved Light Extraction E...
    Liang-Jyi Yan; Sheu, J.K.; Wei-Chih Wen; Tien-Fu Liao; Ming-Jong Tsai; Chih-Sung Chang

    IEEE photonics technology letters, 10/2008, Volume: 20, Issue: 20
    Journal Article

    In this letter, AlGaInP-GaP-based light-emitting diodes (LEDs) were fabricated with an Si substrate and an SiO 2 -ITO-Ag omni-directional reflector using a metal-to-metal bonding technique. To enhance light extraction efficiency, a periodic texture was applied to the (Al 0.5 Ga 0.5 ) 0.5 In 0.5 P 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.