Abstract
We study the polarization of the long-lived component of the band-edge photoluminescence in undoped GaAs/As multiple quantum wells at low temperatures. A high degree of both linear and circular polarizations ( and ) persists over more than 100 nsec and is attributed to separately localized e-h pairs. We show that the long-lived is not due to optical alignment but to resonant excitation and subsequent emission of e-h pairs oriented parallel to the light polarization. The spectral dependence of and on excitation energy indicates that during energy relaxation the e-h pairs preserve their spin orientation but their linear polarization is destroyed.
- Received 29 March 1993
DOI:https://doi.org/10.1103/PhysRevB.49.2935
©1994 American Physical Society