Energy Transfer Processes in (Zn, Mn)S Mixed Crystals

Abstract

Abstract (Zn, Mn)S mixed crystals with Mn concentrations up to 32 mol% and electron‐beam evaporated (Zn, Mn)S thin films are studied by photoluminescence emission, excitation, and decay measurements in the temperature range2 to 300 K. Besides the usual yellow an additional red emission band is observed with the same excitation spectrum. The measured characteristic temperature and Mn‐concentration dependence of the intensities and decay times of both bands are quantitatively discussed on the basis of an effective‐lifetime model assuming a radiationless resonance energy transfer from the primarily excited Mn 2+ ions via several other Mn 2+ ions finally to red emission and nonradiative centres, respectively. This model is further supported by the measured time dependence of the pulse‐excited red emission intensity reaching its maximum only after a Mn‐concentration dependent delay time. Characteristic parameters of the energy transfer between the Mn 2+ ions are determined. The nature of the red emission centres is discussed, especially in connection with the occurrence of octahedrally coordinated Mn 2+ ions at high Mn concentrations.