BINDING-ENERGY OF SHALLOW DONORS IN ASYMMETRICAL SYSTEMS OF QUANTUM-WELLS

The dependence of the binding energy of a shallow donor impunity on it s position in an asymmetrical system of tunnel-coupled quantum wells i s mainly determined by the structure of the one-electron envelope func tions and the difference between the dielectric constants of the quant um-well and barrier materials. An effective technique is suggested for calculating the binding energies and envelope functions of the shallo w donor states in type-I heterostructures with narrow wells and barrie rs. We present the results of calculations for AlxGa1-xAs-GaAs structu res with two or more quantum wells without imposing any restrictions o n the ratios of their sizes. (C) 1997 American Institute of Physics.