Bulk GaN based violet light-emitting diodes with high efficiency at very high current density

We present experimental results on III–nitride light-emitting diodes emitting at 410 nm, grown on low-defectivity bulk GaN substrates. The epitaxial layers are optimized for high peak efficiency and maintain efficiency at very high current densities. We use a volumetric device architecture with surface roughness to maximize light extraction efficiency. We report an external quantum efficiency of 68% at 180 A cm−2⁠. No current crowding is observed at high current density. We also demonstrate flat-line reliable operation to over 1000 h.