IMPURITY STATES IN QUANTUM-WELLS STRUCTURES

The shallow impurity center binding energy in a single quantum well is calculated by using the exact electron-interaction potential. It is shown that the binding energy value corresponding to a simple model Coulomb potential V(e-i) = -e2/epsilon-eff square-root Q2 + (z(e) - z(i))2, epsilon-eff = square-root epsilon-1-epsilon-2, is less than the value, corresponding to the potential roughly by 15%, even for structure with very slightly different layer dielectric permittivities (a GaAs/Al(x)Ga1-xAs structure for example).