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High-efficiency surface-textured LEDs This publication appears in: Compound Semiconductor Authors: R. Windisch, M. Kuijk, B. Dutta, G. Dohler, G. Borghs and P. Heremans Volume: 6 Issue: 4 Pages: 55-58 Publication Date: May. 2000
Abstract: The light extraction from an LED can be enhanced by texturing its top surface in combination with the application of a rear reflector to form a non-resonant cavity (NRC). In such NRC LEDs, the direction of light propagation changes after every internal reflection at the top surface due to scattering at the textured surface. Hence, as the light oscillates between the top surface and the rear reflector, the angle of reflection at the top surface is different for successive reflections. As soon as the photon hits the surface at an angle smaller than the critical angle for total internal reflection, it has a high chance of being extracted from the semiconductor. In this way, surface scattering in combination with a rear reflector significantly enhances the light extraction efficiency of waveguides formed within the LED structure
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