Abstract
We present a systematic study of optical transitions in a modulation doped quantum well with variable concentration of the hole gas. Using a semimagnetic semiconductor as the quantum well material allowed us to control independently the total hole concentration and its distribution between the two spin subbands (by a small magnetic field). Therefore, in transmission experiment we analyze population effects and distinguish the influence of spin-independent effects (screening) from spin-dependent ones (phase-space filling and intensity stealing). The observed variation of the exciton (X) and charged exciton oscillator strengths can be accounted for assuming that the influence of phase-space filling is negligible and the variation of oscillator strength due to screening is found to be similar for both exciton species. We also show that the dissociation energy significantly increases with the population of preexisting carriers with the appropriate spin.
- Received 22 April 1999
DOI:https://doi.org/10.1103/PhysRevB.60.16018
©1999 American Physical Society