Enhanced Exciton-Phonon Interaction in Strained ZnCdSe/ZnSe Quantum Well Structures

Radiative recombination processes in pseudomorphic ZnCdSe/ZnSe structures are compared to those observed in strain-relaxed structures grown on GaAs substrates with thick ZnSe buffer layers. From the temperature dependence of the photoluminescence line width we evaluate the strength of exciton-phonon interaction with acoustic (dominant at lower temperatures) and optical phonons. Stronger exciton-phonon interaction is observed for pseudomorphic structures. Such enhanced exciton-phonon interaction is likely responsible for a faster photoluminescence deactivation at increased temperatures. We also report different exciton properties (photoluminescence intensity, width, strength of exciton-phonon interaction) in quantum well of a given width but in structures grown with different order of quantum wells. More stable photoluminescence (with increasing temperature) is observed for a given quantum well if it is closer to the buffer layer and not to the cap layer.