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High-efficiency 650 nm thin-film light-emitting diodes Host Publication: LIGHT-EMITTING DIODES: RESEARCH MANUFACTURING, AND APPLICATIONS V Authors: C. Rooman, R. Windisch, M. Dhondt, I. Moerman, P. Mijlemans, B. Dutta, G. Borghs, R. Vounckx, M. Kuijk and P. Heremans Publisher: SPIE Publication Date: Jan. 2001 Number of Pages: 5 ISBN: 0-8194-3956-8
Abstract: The external quantum efficiency of planar light-emitting diodes (LED's) can be increased significantly by the approach of a non-resonant cavity (NRC) LED, which consists of texturing the top surface and applying a rear reflector. We demonstrate this approach for the first time on 650-nm InGaP/AlInGaP LED's. The LED's are fabricated using the processing techniques developed previously for 860-nm GaAs/AlGaAs NRC-LED's, which include wet thermal oxidation for the formation of a current aperture. With un-encapsulated NRC-LED's, we report an external quantum efficiency of 24% for an emission wavelength of 655 nm. This is an 11-fold increase of the external quantum efficiency, as compared to conventional devices. Furthermore,, the efficiency is demonstrated to increase to 31% by on-wafer encapsulation of the LED's. This results in an optical output power of 4 mW for a drive current of 7 mA
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