Excitation mechanism in thin-film electroluminescent devices

Abstract

Time-resolved emission spectra of ZnS:TbF thin films in photoluminescence and electroluminescence were measured and compared within a relatively short delay. It was concluded that the excitation mechanism of the Tb center involves energy transfer from the ZnS host in which the Tb-related center acts as an efficient energy source for the excitation of the 4f8 electronic system in the Tb3+ ions. In addition to the ZnS:TbF thin film, a similar excitation mechanism was found to exist in the ZnS:Mn thin film. It is proposed that the TbF complex center and Mn act as an isoelectronic center or deep electron trap in ZnS thin films.