Windisch, R., Kuijk, M., Dutta, B., Knobloch, A., Kiesel, P., Dohler, G., Borghs, G., & Heremans, P. (2001). Non-resonant cavity light-emitting diodes. Proceedings of SPIE, the International Society for Optical Engineering.

@article{2f9051eadf7c46c9b61cb2cf24893f29,
title = "Non-resonant cavity light-emitting diodes",
abstract = "The external efficiency of conventional light-emitting diodes (LED's) is limited by total internal reflection at the semiconductor-air interface. For conventional GaAs-based LED's, this results in an extraction efficiency of 2\%. In non-resonant cavity (NRC) LED's, this problem is overcome by a combination of internal scattering at a textured top surface and reflection on a back mirror, which increases the probability of escape. Using this approach, we demonstrate external quantum efficiencies of up to 40\% without encapsulation of the LED. To gain a more detailed understanding of the out-coupling mechanisms in NRC-LED's, the scattering properties of the textured surface are investigated experimentally. The optimum surface texture is found to randomize the direction of the internally reflected light almost perfectly. In addition, NRC-LED's also enables the enhancement of the external quantum efficiency for small and fast LED's. With efficiencies of about 15\%, we demonstrate bitrates of more than 1.3 GBit/s. In order to modify the lambertian output characteristics, we have successfully applied microlenses, allowing 50\% coupling efficiency into optical fibers with NA=0.5",
keywords = "light-emitting diodes, optical scattering, micro-lenses",
author = "Reiner Windisch and Maarten Kuijk and Barun Dutta and A. Knobloch and P. Kiesel and Godfried Dohler and Gustaaf Borghs and P. Heremans",
year = "2001",
month = jan,
day = "26",
language = "English",
journal = " Proceedings of SPIE, the International Society for Optical Engineering",
issn = "0277-786X",
publisher = "Society of Photo-optical Instrumentation Engineers",
note = "Unknown ; Conference date: 26-01-2001",
}