Charge Transfers in the Red-Copper Luminescent ZnS Phosphors Investigated by Electron Spin Resonance Method

概要

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A photosensitive electron spin resonance signal due to an ionized red-copper luminescence center in Cu-activated ZnS phosphors has been investigated. The excitation spectrum, pulse annealing effect, and isothermal decay of the resonance signal were measured. The observed excitation spectrum indicates that the ionization process of the red-copper center takes place subsequently to the transition of an electron from the Cu^+ level to the S^<2-> vacancy level in the center. By the detection of the red component of thermoluminescence in the phosphors the red-copper luminescence is shown to be accompanied by a long phosphorescence. The good agreement is obtained between the temperature (140°K) where the thermal bleaching of the ionized spin center occurs and that where the 'red' thermoluminescence peak is observed. The isothermal decay curve of the resonance signal shows that the decay process from the ionized state to the ground state is not governed by a simple bimolecular kinetics. On the basis of these results and the behaviors of the Fe^<8+> and Cr^+ signals observed simultaneously, the charge transfers accompanied by the red-copper luminescence are discussed.
社団法人日本物理学会の論文
1967-07-05