AC THIN-FILM ELECTROLUMINESCENT DEVICES WITH RARE-EARTH DOPED ZNS

The fabrication of ZnS:Re, 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 RE3+ ions. The operating voltages have been brought down below 50 V using devices with metal-insulator-semiconductor structure, with Sm2O3 as the insulator. Studies on the effect of halides (F-, Cl-, Br-) and oxide (O2-) on the EL emission spectra of ZnS:Pr TFEL devices show that the fluoride dopant produces the maximum brightness. The brightest of the ZnS:Re, Cl devices studied, ZnS:Tb, Cl, has a brightness of about 500 fL, about one-third that of a typical ZnS:Mn EL cell.