SOLID STATE RADIATION-INDUCED PHENOMENA

The relationship between fluorescence, fluorescence quenching, light stimulation, glow areas, and the photoinduced EPR signals in excited Cr, Cu activated ZnS phosphors was studied. Two types of trap levels exist: deep traps due to chromium and shallow traps located in the neighborhood of ionized Cu activators; their trap populations are determined. AC impedance measurements on photo-excited CdS single crystals mounted between insulating layers was carried out. The use of insulating layers eliminates electron and hole injection and allows one to study the motion of the electrons inside the crystals separately. The transfer of excitation energy in organic solvents was investigated as function of temperature. It is reduced with increasing temperature. This is, to a large part, due to the decrease of the lifetime of the excited solvent molecule. The charge injection from unexcited inorganic layers into various organic solvents under illumination, and the charge exchange between organic solvents and crystals was studied. (Author)