The effect of Mn concentration on the photoluminescence of ZnS:Mn

Thin films of ZnS with a zinc to sulphur ratio of about 1.13 were prepared by radiofrequency sputtering and were subsequently implanted with Mn ions. Luminescence was observed for Mn concentrations (C) of between 0.1 and 3 at.% after annealing at temperatures (T A ) between 300 and 500 degrees C. The intensity (I) of the total photoluminescent signal can be described empirically as I approximately C exp(E A /kT A )-C 2 exp(-E B /kT A ) where E A and E B represent activation energies of 0.65 and 0.94 eV respectively. The intensity arising from the first term of this equation is ascribed to single Mn ions whereas the quenching described by the second term possibly results from the interaction between pairs of Mn ions.