Factors determining the external quantum efficiency of AlGaInP microcavity light-emitting diodes

A detailed study of external quantum efficiency is reported for AlGaInP-based microcavity light-emitting diodes. By comparing numerical simulations with angle-resolved spectral measurements, the extraction efficiency could be accurately determined. This allowed precise calculation of the internal quantum efficiency. By using a simple model, we could identify the contributions of radiative and injection efficiencies to the internal quantum efficiency. We showed that the injection efficiency was limited by poor confinement of the electrons in the active region.