Dynamics of Free Exciton Luminescence in ZnTe/Cd sub (x) Zn sub (1-x) Te Quantum Wells

We report on the dynamics of excitons in ZnTe/Cd sub (x) ZN sub (1-x) Te multiple quantum wells studied by absorption, photoluminescence, and photoluminescence exciton (PLE). In addition, the decay of the photoluminescence under pulsed excitation (6ps FWHM) was measured with picosecond resolution. In PLE we observe broad and sharp features associated with the free exciton which are not seen in absorption. The broad features show that LO-phonon assisted absorption directly into the exciton band takes place and accounts for up to 50% of the luminescence.