Structural defects and degradation of high power pure-blue GaN-based laser diodes

In order to elongate lifetime of high power pure-blue GaN based laser diodes, reduction of newly created structural defects at active region, which consists of multiple quantum well structures, is inevitable. We, first, report on detailed structural analysis of this new type defects and discuss formation mechanism and reduction methodology of these defects. We, then, fabricated laser diodes with current injection-free structure at front facets, which is confirmed to be effective for suppression of degradation by catastrophic optical damage. We also discuss degradation mechanism of the laser diodes.