Temperature-dependent luminescence dynamics in ZnO nanorods

We report on an experimental study of the temporal photoluminescence dynamics of high-quality ZnO nanopillars from 10 K to room temperature. We find that defect states play an important role in the time evolution of the photoluminescence signal. At low excitation intensities capture into defects dominates the time dependence of the PL, at higher intensities they are saturated and the intrinsic excitation decay is observed. We separate the intrinsic exciton decay from the fast nonlinear M-band with the method of decay associated spectra and obtain the temperature dependence of the intrinsic exciton decay. High excitation measurements show a reduced exciton-exciton scattering in these thin nanorods.