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

The electronic subband of delta-doped AlGaAs/GaAs heterostructure has been studied theoretically by the finite differential method. We use an efficien t self-consistent analysis to solve simultaneously the Schrodinger and Pois son equations. The results show the possibility to increase the electron de nsity in the channel by the introduction of the silicon delta doping in a q uantum 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 te st the validity of our calculation, we have grown, by molecular beam epitax y, a series of delta-doped AlGaAs/GaAs heterojunctions having various alloy compositions seen by the silicon. If we consider the spreading of the sili con in space during the delta-layer growth, we show that the theoretical mo del explains well the experimental Hall data for all aluminum concentration s. (C) 1999 American Institute of Physics. [S0021-8979(99)01611-4].