We present a discussion of the brightness–voltage (B–V) response of thin-film electroluminescent (TFEL) devices prepared by the simultaneous evaporation of ZnS and Mn (or MnS) using two separate sources. Crystal structure, threshold voltage, saturation brightness, and memory margin of the B–V characteristics have been studied as a function of the deposition rate of dopant material relative to ZnS. Optimum annealing conditions of the devices are also given. These results indicate that co-evaporation can be advantageously employed to fabricate memory TFEL display devices with excellent characteristics.