Binding energy of the impurity level in the Ga1−xAlxAs−GaAs−Ga1−yAlyAs superlattice

Abstract

The binding energy of the first impurity level in the ${\mathrm{Ga}}_{1-x}{\mathrm{Al}}_x\mathrm{A}\mathrm{s}-\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}-{\mathrm{Ga}}_{1-y}{\mathrm{Al}}_y\mathrm{As}$ superlattice is investigated by considering a variational problem in a finite quantum well with a hydrogenic impurity potential. For the case of the finite well, we first deal with the dependency of the binding energy on the impurity position and on the barrier heights of the quantum well. Each barrier height is independently changed in the present study. It is pointed out that the binding energy is underestimated when one employs an infinite barrier height to represent the quantum well. The electron distribution in the superlattice depending on various impurity positions is also discussed.