The exhaustion of traps in ZnS phosphors by electric field and the Gudden-Pohl effect

Abstract

The change of thermoluminescence intensity of certain ZnS powder phosphors brought about by an external dc field applied after excitation with ultraviolet light (366 nm) is described and compared with the light flash intensity resulting from the effect of the same field on the phosphor (Gudden‐Pohl effect). It is established that the intensity of thermoluminescence is considerably diminished by the previous application of the field which produces a strong Gudden‐Pohl effect. The change in thermoluminescence intensity as well as the flash intensity decrease if the temperature at which the field is applied diminishes. The results are explained by considering an external field to release electrons from traps. The experimental results are compared with a tunneling mechanism of electron release with phonon participation.