AlGaInN laser diodes grown on an ELO-GaN substrate vs. on a sapphire substrate

The lifetime of AlGaInN-based violet laser diodes is restricted by the high dislocation densities caused by the large difference between the lattice constants and thermal expansion coefficients of GaN and sapphire. In order to reduce the dislocation density, epitaxial lateral overgrowth (ELO) techniques have been proposed, leading to the higher performance of AlGaInN lasers. In this work, we compared the lasing characteristics of AlGaInN lasers grown on ELO-GaN with those grown on sapphire substrates.