Electronic Energies in Delta Doped AlGaAs/GaAs Heterostuctures

The band bending of the potential at the AlGaAs/GaAs interface increases with the electrons concentration in the GaAs channel. This band bending is often ignored in the theoretical calculation of the electronic energies and a linear potential approximation was used. This led to imprecise energy values and occupied subband configurations. We have taken account of the band bending in the subband energies calculation. The potential expression was considered as sum of linear and quadratic terms. The quadratic term was considered as a time independent perturbation and the electronic energies were corrected to the first order. We have calculated the Fermi energy for different electronic concentrations. The relation between the Fermi energy and the electronic concentration at the interface leads to the desired configuration of the occupied subbands. When the fundamental subband is only occupied, the characteristics of those heterostructures are best enhanced. The corresponding electronic concentration was calculated. The theoretical results were used for the determination of the active electron concentration in two AlGaAs/GaAs heterostructures.