TY - JOUR
T1 - Effect of surface texture and backside patterned reflector on the AlGaInP light-emitting diode
T2 - High extraction of waveguided light
AU - Lee, Ya Ju
AU - Lee, Chia Jung
AU - Chen, Chih Hao
N1 - Funding Information:
Manuscript received November 4, 2010; revised January 11, 2011; accepted January 17, 2011. Date of current version March 25, 2011. This work was supported in part by the National Science Council of China in Taiwan under Contract NSC-98-2112-M-003-001-MY2.
PY - 2011
Y1 - 2011
N2 - 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.
AB - 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.
KW - AlGaInP
KW - light emitting diode
KW - waveguided light
UR - http://www.scopus.com/inward/record.url?scp=79953174946&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79953174946&partnerID=8YFLogxK
U2 - 10.1109/JQE.2011.2107891
DO - 10.1109/JQE.2011.2107891
M3 - Article
AN - SCOPUS:79953174946
SN - 0018-9197
VL - 47
SP - 636
EP - 641
JO - IEEE Journal of Quantum Electronics
JF - IEEE Journal of Quantum Electronics
IS - 5
M1 - 5738955
ER -