Strongly directional emission from AlGaAs/GaAs light emitting diodes

We show for the first time that strongly directional emission of defined polarization can be achieved from conventional AlGaAs/GaAs double heterostructure surface emitting LEDs via coupling to surface plasmons. By microstructuring the surface, we have fabricated LEDs with a beam divergence of less than 40 and a drastically increased quantum efficiency. We prove that surface plasmon excitation aid emission mechanism has the potential to overcome basic external quantum efficiency losses and to improve the performance of LEDs.