Dislocation glide velocities in various light-emitting devices were estimated. It was found that the results were consistent with device degradation rates that were related to dislocation motion. It was concluded that the long lifetimes of GaN-based devices with a high dislocation density was due mainly to an extremely low dislocation mobility. The latter was partly due to the small shear stress that was available for dislocation motion, and was only slightly due to a radiation enhancement effect.

L.Sugiura: Applied Physics Letters, 1997, 70[10], 1317-9