Abstract
Using electroluminescence topography, we observed that a rapid degradation of an AlGaAs/GaAs quantum-well laser on Si was caused by the rapid growth of <100> dark linedefects (DLD's), and that the growth velocity was strongly dependent on the injected currentdensity. A typical lifetime of the AlGaAs/GaAs laser on Si was a few minutes. In contrast, weobserved that the growth of <110> DLD's for an AlGaAs/In0.07Ga0.93As strained quantum well laser on Si was slow compared with that of <100> DLD's, the longest life time observedin the present study was about 24 hours. This result indicates that the degradation mechanismof the A1GaAs/InGaAs laser on Si is different from that of AlGaAs/GaAs laser on Si. The improved life time seems to be caused by not only tensile stress reduction but also dislocation pinningdue to the introduction of indium in the GaAs active layer.
