The effects of silicon and beryllium on the interdiffusion of GaAs/ AlxGa1−xAs and InxGa1−xAs/GaAs quantum well structures

The effects of silicon and beryllium at doping levels of up to 1019 cm−3 on the interdiffusion of GaAs/AlxGa1−xAs and InxGa1−xAs/GaAs quantum wells after annealing have been studied using photoluminescence. It was found that for beryllium concentrations up to 2.5 ×1019 cm−3 and for silicon doping concentrations up to 1018 cm−3, no change in the interdiffusion coefficients could be measured. For a silicon doping concentration of 6×1018 cm−3 a dramatic degradation of the material quality was observed following annealing at 750 °C for 15 s. This resulted in the luminescence from the well disappearing and the appearance of deep level luminescence related to donor‐gallium vacancy complexes and arsenic antisite defects. From these results we suggest that the position of the Fermi level plays no role in the intermixing of III‐V heterostructures and that most of the enhanced intermixing observed in silicon‐doped GaAs/AlxGa1−xAs structures is related to silicon relocation at very high doping levels.