Coupling between a donor potential and quantum wells: Effect on binding energies

Considering the coupling between a donor potential and quantum wells, we have obtained an excellent trial function for donor ground states in both single-quantum-well (SQW) and multiple-quantum-well (MQW) structures. A variational calculation is performed and larger binding energies of donor ground states in narrow wells and their maxima are obtained. Calculated results show that the coupling effect is dependent on the barrier height and well width and is stronger in MQW's than in SQW's. From a comparison with the results of Mailiot, Chang, and McGill, it is shown that the coupling effect on the maximum binding energies is as important as that of the differences of the effective masses and dielectric constants between GaAs and Ga_1-x{Al}ₓ$As.