QUENCHING OF ZINC-OXIDE PHOTOLUMINESCENCE BY D-TRANSITION AND F-TRANSITION METAL-IONS

The photoluminescence of semiconducting zinc oxide doped with nickel, cobalt or neodymium ions has been studied. It is shown that the d-transition metal ions strongly deactivate the global emission of zinc oxide by two quenching processes: energy transfer to the transition metal ion (mainly) and trivial reabsorption of ZnO luminescence. By doping with neodymium ions the principal deactivation process is light reabsorption, but due to multiple internal reflection or the mobility of the charge carriers in the semiconducting samples, a mismatch between the theoretical approach and the experimental results is observed. Using samples of different thickness (0.1-1 mm) evidences are shown for mean path lengths of light longer than those predicted by the theory. © 1990.