ac–dc Electroluminescence in ZnS (Powder and Single Crystal)

Abstract

The enhancement effect (E.E.) of ZnS is measured in a constant electric field superposed on an alternating field. Two cases are considered: a) a conventional sandwich-type electroluminescent (E.L.) ZnS (Mn, Cu, Cl) micropowder cell; b) a ZnS (Cu, Cl) single crystal ("gap") cell.Capacity, current, and 6 are simultaneously measured at different temperatures between 88 and 300 OK using frequencies in the range 6 to 20 kHz. The frequency corresponding to R, , , is determined. The variation of R near R,, is found to be independet of tg 6. The value of the time constant of the E.L. cell is equal to half a period of the optimum applied frequency. The results are consistent with both the