AC Thin Film Electroluminescent Devices with Rare Earth Doped ZnS

The fabrication of , Cl thin‐film electroluminescent (TFEL) devices and their emission characteristics are described. The various emission bands and lines observed in the spectra are assigned to the transitions within the RE 3+ ions. The operating voltages have been brought down below 50 V using devices with metal‐insulator‐semiconductor structure, with as the insulator. Studies on the effect of halides (F − , Cl − , Br − ) and oxide on the EL emission spectra of TFEL devices show that the fluoride dopant produces the maximum brightness. The brightest of the , Cl devices studied, , Cl, has a brightness of about 500 fL, about one‐third that of a typical EL cell.