For the yellow-to-red spectral region, the quaternary AlGaInP material system, grown by low-pressure metal-organic chemical vapour deposition (MOCVD), has proven to be the best choice in many applications such as interior and exterior automotive lighting, traffic lights, full colour displays, and all kinds of indoor and outdoor signs. An n-side-up AlGaInP-based LED operating at a wavelength of 630 nm with a stripe-patterned omni-directional reflector (ODR) was fabricated by adopting the adhesive-layer bonding scheme. It is demonstrated that the periodic and geometrical shape of the stripe-patterned array improves the light extraction efficiency by increasing the extraction of guided light. Compared to the conventional ODR LED, the stripe-patterned ODR LED significantly enhanced the output power and with only a slightly higher forward voltage. This improvement was analysed by the scanning near-field optical microscope (SNOM) and the optimized dimension of stripe patterns was also calculated on the basis of a Monte Carlo ray tracing simulation. According to the above analysis, the increase of light extraction could not only be attributed to the geometrical shape of the stripe patterns that redirect the trapped light towards the top-escaping cone of the LED surface but also to the repetitive stripe-patterned array of diffracting elements that effectively diffract the guided light outside the LED surface. Moreover, the optimized dimension of the stripe pattern is 3 micro-m wide, 2 micro-m deep and spaced 3 micro-m apart, which coincides with experimental results.
High brightness AlGaInP-based light emitting diodes by adopting the stripe-patterned omni-directional reflector
Semiconductor Science and Technology ; 21 , 2 ; 184-189
2006
6 Seiten, 7 Bilder, 14 Quellen
Article (Journal)
English
Aluminiumverbindung , Bragg-Reflexionsbedingung , CVD-Beschichten , Galliumarsenid , Galliumindiumphosphid , Galliumverbindung , Haftschicht , Leuchtdiode , Lichtreflektor , Monte-Carlo-Methode , Nahfeld-Rastermikroskopie , Optimierungsalgorithmus , Streifenmusterung , Substrat , Superlumineszenzdiode , MOCVD (metallorganische CVD)
High Performance AlGaInP Light-emitting Diodes
IEEE | 1993
|High Performance AlGaInP Light-Emitting Diodes
British Library Conference Proceedings | 1993
|Internal Omni-Directional Reflector Using a Low Refractive Index Material for Light-Emitting Diodes
British Library Conference Proceedings | 2005
|Very High-Efficiency Transparent-Substrate AlGaInP/GaP Light-Emitting Diodes
British Library Conference Proceedings | 1994
|