Title :
High-Efficiency 1-mm 2 AlGaInP LEDs Sandwiched by ITO Omni-Directional Reflector and Current-Spreading Layer
Author :
Hsu, Shun-Cheng ; Wuu, Dong-Sing ; Lee, Chong-Yi ; Su, Juh-Yuh ; Horng, Ray-Hua
Author_Institution :
Dept. of Mater. Sci. & Eng., Nat. Chung-Hsing Univ., Taichung
fDate :
4/1/2007 12:00:00 AM
Abstract :
A 1-mm2 AlGaInP light-emitting diode (LED) sandwiched by an omni-directional reflector (ODR) and current-spreading layer is presented. The vertical-conducting bottom ODR consists of p-GaP, dispersive dot-contacts of Au-AuBe-Au acting as ohmic contacts, an intermediate low-refractive index layer of indium-tin-oxide, and a silver layer. A Si substrate, which acted as a heat sink, was bonded to the ODR-covered LED structure using a metal-to-metal bonding process. It was found that the maximum output power of the ODR-LED on Si reached 304 mW at 650 mA, and the output power did not saturate up to 650-mA injection current. The external quantum efficiency of 31.8% was obtained at 100 mA, and 19.4% achieved even at currents of up to 800 mA. Furthermore, under a forward current of 350 mA, the ODR-LEDs remained highly reliable after 1000-h testing at room temperature
Keywords :
III-V semiconductors; aluminium compounds; bonding processes; gallium compounds; gold; gold compounds; heat sinks; indium compounds; integrated optoelectronics; light emitting diodes; mirrors; ohmic contacts; refractive index; semiconductor quantum dots; 100 mA; 1000 h; 293 to 298 K; 304 mW; 350 mA; 650 mA; 800 mA; AlGaInP; AlGaInP LED; Au-AuBe-Au; GaP; ITO; InSnO; Si; Si substrate; current-spreading layer; device reliability; dispersive dot-contacts; heat sink; indium-tin-oxide reflector; light-emitting diodes; metal-to-metal bonding; ohmic contacts; omnidirectional reflector; p-GaP contacts; refractive index layer; room temperature testing; silver layer; vertical-conducting bottom reflector; Conductivity; Dispersion; Gallium arsenide; Indium tin oxide; Light emitting diodes; Materials science and technology; Ohmic contacts; Power generation; Substrates; Wafer bonding; AlGaInP; current spreading layer; light-emitting diode (LED); omni-directional reflector (ODR);
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2007.893820
