TY - JOUR
T1 - Improved light extraction efficiency in AlGaInP light-emitting diodes by applying a periodic texture on the surface
AU - Yan, Liang Jyi
AU - Sheu, J. K.
AU - Wen, Wei Chih
AU - Liao, Tien Fu
AU - Tsai, Ming Jong
AU - Chang, Chih Sung
N1 - Funding Information:
Manuscript received April 18, 2008; revised August 4, 2008. Current version published September 26, 2008. This work was supported in part by the National Science Council under Grant NSC 96-2112-M-006-013-MY3. L.-J. Yan and J. K. Sheu are with the Advanced Optoelectronic Technology Center and Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan 70101, Taiwan (e-mail: [email protected]). W.-C. Wen, T.-F. Liao, M.-J. Tsai, and C.-S. Chang are with High Power Opto. Inc., Daya Township, Taichung County 42878, Taiwan. Color versions of some of the figures in this letter are available online at http:// ieeexplore.ieee.org. Digital Object Identifier 10.1109/LPT.2008.2004564
PY - 2008/10/15
Y1 - 2008/10/15
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=54049131759&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=54049131759&partnerID=8YFLogxK
U2 - 10.1109/LPT.2008.2004564
DO - 10.1109/LPT.2008.2004564
M3 - Article
AN - SCOPUS:54049131759
SN - 1041-1135
VL - 20
SP - 1724
EP - 1726
JO - IEEE Photonics Technology Letters
JF - IEEE Photonics Technology Letters
IS - 20
ER -