Laser operation-induced migration of beryllium at mirrors of GaAs/AlGaAs laser diodes

Laser operation-induced migration of beryllium at laser mirrors was studied by electron-beam-induced current. The devices investigated were single quantum well graded index separate confinement GaAs/AlGaAs ridge geometry laser diodes. In these devices, an operation-induced displacement of the p-n junction towards the n-type cladding has been observed close to the mirrors. A similar effect was induced by electron irradiation of the mirror facets in a scanning electron microscope. These effects have been attributed to recombination-enhanced diffusion/migration of beryllium from the p-type cladding. We have measured the diffusion coefficient of beryllium and, from this value, have estimated the average mirror temperature during laser operation. This temperature was found to be in excellent agreement with recently published measured mirror temperatures.