Hot-Electron Impact Excitation of ZnS:Tb Alternating-Current Thin-FilmElectroluminescent Devices

摘要

A new method of performing hot electron impact excitation experiments usingalternating current thin film electroluminescent (ACTFEL) devices is reported. This method relies on the use of a field control circuit to control the magnitude of the phosphor field and consists of plotting the intensity of a given electroluminescence transition, normalized by the amount of conduction charge which flows while the field control circuit is asserted (the electroluminescence intensity of a given transition divided by the conduction charge is denoted the impact excitation quantum yield eta sub ie) as a function of the phosphor field F sub p (dot) eta sub ie vs F sub p is measured for ZnS:Tb ACTFEL devices fabricated by atomic layer epitaxy (ALE) and by sputtering. eta sub ie exhibits a threshold at approximately 0.5 MV/cm and saturation at approximately 1.5 MV/cm. The magnitude of eta sub ie for the ALE ACTFEL device depends' strongly on temperature; in contrast, eta sub ie for the sputtered ACTEEL device is virtually temperature independent.