Degradation of III‐nitride laser diodes grown by molecular beam epitaxy

The defects found in electrically degraded GaN-based lasers have been characterised by transmission electron microscopy. In a laser that had been operated until failure, defects containing contact metals were observed. Combined with data from the laser's current-voltage characteristics, this suggests that the catastrophic failure may have been caused by local heating. In partially degraded lasers, four different types of defects were observed: cracks, stacking faults, inversion domains and dislocations. Cracks, stacking faults and inversion domains were present before and after the laser failure. The dislocation network, however, was only observed in the active region of a failed laser and may have resulted from recombination enhanced defect migration. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)