EXCITONIC TRION X- IN SEMICONDUCTOR QUANTUM-WELLS

The ground-state energy of the negatively charged exciton in a semicon ductor quantum well is calculated assuming finite band offsets in a tw o-band model within the envelope-function approximation with isotropic electron and hole masses. A variational 66-term Hylleraas-type wave f unction has been used. The stability against dissociation into an exci ton and a free electron is investigated in the cases of GaAs/Ga1-xAlxA s and CdTe/Cd1-xZnxTe quantum wells with several compositions and diff erent values of the well width. A stable binding is obtained in all ca ses. The calculated transition energies are in reasonable agreement wi th the available experimental values. A particular experiment is propo sed in order to identify charged excitons and to distinguish them from neutral donor bound excitons.