Decay of Cathodoluminescence and Nonradiative Processes in Manganese Activated Phosphors

Abstract

Cathodoluminescence emission spectra and decay processes have been investigated as a function of primary electron energy and density for single crystals, evaporated layers, and powder layers of manganese activated calcium fluoride and zinc silicate. The emission spectra were found to be unchanged by the conditions of excitation. The value of the decay constant for powder layers was also unchanged, but that for single crystals and evaporated layers increased as the primary energy was decreased. This behavior is explained in terms of an Auger recombination leading to an interaction between the luminescence centers and the high density of electrons in the conduction band at low primary voltages. It is shown that for such an effect to occur the rate of nonradiative recombination of electrons in the conduction band of the host lattice must be small. This criterion is satisfied in the case of single crystals and evaporated layers, but not in microcrystalline powder layers.