Luminescence and energy transfer processes in ensembles and single Mn or Tb doped ZnS nanowires

Zinc sulfide (ZnS) nanowires with a typical diameter of 100 to 300 nm have been doped with different concentrations of either Mn or Tb using ion implantation. Both systems show very efficient and long living intra-shell luminescence with strong non-exponential decay characteristics in the range of milliseconds. The time behavior of the corresponding luminescence is well described within a modified Forster model, taking into account the lower dimensionality of the nanowires in case of radiationless dipole-dipole energy transfer. The general applicability of this model for energy transfer processes in low dimensional systems will be shown as a function of concentration, temperature, excitation density as well as for measurements on the level of single nanowires.