  The temperature-dependent linewidths of excitons in ZnO quantum wells were
studied by measuring absorption spectra from 5 K to room temperature. We
deduced experimentally the exciton-longitudinal-optical (LO) phonon coupling
strength, which showed reduction of coupling with decrease in well width. This
reduction was explained in terms of confinement-induced enhancement of the
excitonic binding energy by comparing the binding energy dependence of
calculated coupling strength.
