Exciton-longitudinal optical phonon coupling in a ZnSe-Zn0.75Cd0.25Se double-superlattice at 1.4 K

Photoluminescence and photoluminescence excitation spectra have been employ ed to study the phonon emission process in a ZnSe-Zn0.75Cd0.25Se double-sup erlattice at 1.4 K. Since the excitation energy is higher than the excitoni c energy of the superlattice sample, excitons with a large kinetic energy w ill be generated. These excitons will then decay by emitting mainly longitu dinal optical phonons and reach the bottom at K = 0. The transitions of n = 1 heavy- and light-hole hot excitons from a narrow well. superlattice are observed through the LO-phonon energy m (h) over bar omega. The results sho w that the n = 2 heavy-hole excitonic band (E-2hh(1)) in the wide well supe rlattice (SL1) reabsorbs the radiation, generated by both, the n = 1 light- hole (E-11h(2)) and heavy-hole (E-1hh(2)) excitonic bands of an adjacent na rrow well superlattice (SL2). (C) 1999 Published by Elsevier Science Ltd. A ll rights reserved.