Thermal rollover characteristics up to 150 °C of buried-stripe type 980-nm laser diodes with a current injection window delineated by a SiNx layer

In order to improve device robustness of buried-stripe type 980-nm laser diodes against excess current injection even under high temperature operation, we have introduced a current injection window delineated by a SiNx layer to suppress current injection near the facets. The devices showed complete thermal rollover characteristics at temperatures up to 150 degrees C with 800-mA continuous-wave current injection while devices without the layer failed due to front facet degradation during high temperature tests. We think the improvement of device robustness with a SiNx layer is attributable to suppression of nonradiative recombination of carriers overflowing from the active layers near the facet and to reduced light absorption at the facet brought about by suppression of carrier-induced bandgap shrinkage.