CATION SUBLATTICE ORDERING IN GAXIN1-XAS QUANTUM-WELLS - EVIDENCE FROM ELECTRON-PHONON INTERACTION

We report experimental evidence for long-range ordering in thin strain ed layers. Our novel approach to probe long-range ordering is based on the study of longitudinal-optic sidebands of exciton photoluminescenc e. The sideband intensity is used as a measure of exciton localization in the plane of the quantum well. The transition from ordered arrange ment to the truly random alloy of Ga0.63In0.37As and vice versa manife sts itself in a well defined maximum of the intensity ratio as a funct ion of the composition in the interval 0.50 < x < 0.75. Our concept is based upon the theory for Frohlich interaction in a two-mode system.