Elektrophotolumineszenz eines Zink-Cadmium-Sulfid-Phosphors in Abh�ngigkeit von Anregungswellenl�nge und Feldimpulsbreite

Abstract

Luminescence flashes in an excited ZnCdS (Ag) phosphor occur when electric fields are put on or off. Whether these flashes are positive or negative depends on the length of the field pulse, on the exciting wavelength, and on the polarity of the irradiated electrode. There is a critical duration of the field pulses for which no field-off flash appears. At another but related critical time, the flashes with periodic field applications change sign. These times change with the exciting wavelength. The observations are interpreted as being controlled by the gradual filling of surface traps, which in its turn is influenced by the distribution of electron and hole concentrations produced by the incident radiation and the electric field. The critical time is approximately equal to the time needed for completely filling the surface traps.