Transmission electron microscope observation of dark defects appearing in InGaAsP/InP double heterostructure lasers aged at accelerated operation

Transmission electron microscopy contrast analysis is presented to reveal the nature of the defects associated with the active region in degraded InGaAsP/InP double heterostructure lasers. Dislocation loops elongating in the [11̄0] direction and platelike precipitates lying in the {111} planes associated with the above dislocation loops have been observed to correspond to dark spot defects appearing in electroluminescence pattern of the lasers operated at 10-kA/cm2 current density at 250 °C junction temperature.