Effect of current spreading on luminescence improvement in selectively oxidized AlGaInP light-emitting diodes

We have systematically investigated the luminescence performance of AlGaInP light-emitting diodes with a wet-oxidized AlAs/AlGaAs distributed Bragg reflector structure. The peak intensity for a 20-mum-radius aperture is 4.2 times greater than that for a 100-mum-radius aperture at the same current density. We believe that this significant improvement in the emission characteristics with the AI-based native oxides is the result of the current-spreading effect. With an increase in the lateral depth of the oxidized layer, the near-field patterns become more centralized. This is attributed to the confinement of the current to the region about the unoxidized aperture. We also found that the centralized carriers contribute to the enhancement of the external quantum efficiency per unit area up to factor of 58.6. (C) 2003 American Vacuum Society.