The degradation behaviour of two InGaAs/AlGaAs laser structures
differing only in the Zn doping concentration of the p+ GaAs
contact layer has been compared. The ageing tests used in this
comparison are performed on lasers with Anti-Reflection (AR)
coatings on both facets, so as to increase the carrier density
in the quantum well and the gradual degradation rate. This kind
of ageing test has been discussed in a previous paper, where
a possible effect of Zn diffusion was suspected. The defects
generated during ageing are studied by Low Temperature (80 K)—Spectrally
Resolved Cathodo-Luminescence (LT-SRCL), Cathodo-Luminescence
Imaging (CLI) and Transmission Electron Microscopy (TEM). The
impact of the acceptor concentration in the contact layer is
thus clarified.