Effect of the p(+)-GaAs contact layer doping level on the gradual degradation of InGaAs/AlGaAs pump lasers
01 July 2004
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.