880-nm surface-emitting microcavity light-emitting diode

Abstract

Microcavity light emitting diodes (MCLEDs) are planar emitting devices that can achieve large brightness increase compare to conventional LEDs. We designed and fabricated a GaAs/AlxGa1-xAs surface-emitting MCLED emitting at 880 nm. Two InGaAs quantum wells are included in a (lambda) -Al0.3Ga0.7As cavity between two Al0.1Ga0.9As/Al0.8Ga0.2As Bragg mirrors. The top n-doped Bragg mirror has 4 pairs, the bottom one is p-doped like the substrate and has 20 pairs. The detuning between the source emission wavelength and the Fabry Perot wavelength is -20 nm. It is optimum for an extraction into air. By inserting the bonded MCLED device into an integration sphere we measured a maximum external quantum efficiency of 14% at 10 mA. An epoxy lens is placed on top of the device and the external quantum efficiency is increased up to 20.5% at 10 mA. These values are in good agreement with theoretical calculations if the internal quantum efficiency of the structure is equal to 85%. Additional calculations and measurements are performed and lead to a good physical understanding of the MCLED.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.