Abstract
Exciton binding energies of heavy- and light-hole excitons affected by charge-carrier screening in GaAs-As quantum wells are calculated by the variational-perturbation method. The exciton binding energies are found to decrease rapidly when the screening length is less than 30 (effective exciton Bohr radius). This screening length corresponds to a carrier density of 7.0×/ at T=10 K. In the calculation, the Debye screening model is used for charge carriers. The exciton binding energies as functions of the screening length, carrier density, and quantum-well parameters have been calculated. The critical carrier densities, above which no excitons can be formed, are obtained at different well thickness. The effects of charge-carrier screening to the exciton photoluminescence are also discussed.
- Received 18 June 1992
DOI:https://doi.org/10.1103/PhysRevB.47.2101
©1993 American Physical Society