INFLUENCE OF GROWTH-CONDITIONS ON EXCITON PROPERTIES IN THIN QUANTUM-WELLS OF GAAS ALGAAS/

Exciton properties in growth interrupted quantum wells of GaAs/AlGaAs are compared with those observed for structures grown without growth i nterruption during the molecular beam epitaxy process. We report obser vation of quasi-localized excitons in quantum well structures grown wi thout growth interruptions. Quasi-localized excitons drift towards the states of a lower potential energy in the quantum well. For growth in terrupted MBE structures islands with a constant quantum well thicknes s become large compared to the exciton radius. Free or lightly localiz ed excitons are observed in that case.