Improvement of the electron density in the channel of an AlGaAs/GaAs heterojunction by introducing Si δ doping in the quantum well

The electronic subband of δ-doped AlGaAs/GaAs heterostructure has been studied theoretically by the finite differential method. We use an efficient self-consistent analysis to solve simultaneously the Schrodinger and Poisson equations. The results show the possibility to increase the electron density in the channel by the introduction of the silicon δ doping in a quantum well, where the Al concentration is smaller than in the barrier. The effect of the quantum well width is studied on the electron density. To test the validity of our calculation, we have grown, by molecular beam epitaxy, a series of δ-doped AlGaAs/GaAs heterojunctions having various alloy compositions seen by the silicon. If we consider the spreading of the silicon in space during the δ-layer growth, we show that the theoretical model explains well the experimental Hall data for all aluminum concentrations.