Be migration effect in low-dimensional laser structures of GaAs/AlGaAs

The SIMS depth profiles of Al, Ga and Be were investigated in the GaAs/AlGaAs GRIN SCH SQW laser diode structures grown by MBE at various substrate temperatures. Additionally, the SIMS distributions of Si and O in MMQW laser structures with undoped and Si doped active regions grown at constant temperature are also shown. Because the diffusion coefficient of Be is significantly larger than that of Si the effect of p-n junction displacement is observed from the active QW region towards the n-AlGaAs dadding layer in structures with the undoped active region and grown in high temperature. Our results confirmed results obtained by other authors which indicate that the movement of Be atoms is stopped when the central region is doped with Si. Simultaneously, it was also observed that amount of O accumulated at the GaAs/AlGaAs heterointerface was reduced. It was concluded that decreasing of amount of O together with the control of the Si doping profile are of the significant importance from the point of view of the laser operation. (author)