Phenomenological kinetic equation for Mn luminescence in ZnS films

In this paper time-resolved measurements of Mn2+ luminescence in ZnS electroluminescent layers grown by atomic layer epitaxy are reported. The Mn concentration ranges from 0.03 to 1.4 mol %. The intensity of the luminescence versus time is cast in the form of a kinetic equation instead of an algebraic formula. This allows one to determine on a purely phenomenological basis the kinetic rates of mono- and bimolecular processes responsible for the relaxation. We show by a Laplace transform analysis technique that the long-time behavior is not dominated by the lifetime of the single Mn2+ ion in the host matrix. The influence of the electrical properties is evidenced on the second-order kinetic rate. The methods used provide a general framework for investigating complex decay processes.