Recent progress of nitride-based light emitting devices

We review the recent progress of nitride-based light-emitting diodes (LEDs) and discuss the relation between dislocation density and quantum efficiency. We also discuss how to improve the external quantum efficiency of nitride-based LEDs. Secondly, the group-III nitride laser diodes (LDs), which emit from near-ultraviolet to pure-blue, are reviewed. Reducing threading dislocations can increase the lifetime of nitride LDs. Using the epitaxial lateral overgrowth technique, a dislocations density of the order of 10 5 cm -2 has been obtained. The relation between the lifetime of nitride LDs and the density of dislocations is discussed. Finally, near-ultraviolet LDs and pure-blue LDs are described.