Pressure effect on the binding energies of donors in GaAs/AlxGa1−xAs heterojunctions

A variational method is developed to investigate the binding energies of donors near the interfaces in the GaAs/AlxGa1−xAs heterojunctions by considering the pressure effect. The influence of a realistic interface potential and the effect of conduction band bending are considered by a self-consistent calculation. The screening effect of the electron gas on the impurity Coulomb potential is also taken into account using a random phase approximation. The numerical computation has been performed for the Al concentration x=0.3 and the pressure region from 0 to 40 kbar. The donor binding energies versus pressure, impurity position and electron density are given, respectively. The result indicates that the donor binding energies increase with pressure obviously.