The structure and photoluminescent properties of the ZnF2: Mn thin films deposited by electron beam evaporation relating to the preparation conditions has been investigated. It was found that when the pressure is of the order of 10-6Torr, a fraction of the film is oxidized to ZnO if the substrate temperature is higher than 400°C. This oxidation process could not be observed even at 500°C if the pressure lies in the order of 10-8Torr. The crystallinity of the film was improved with increasing the substrate temperature and decreasing the pressure. Fluoride thin-film EL devices consisted of ZnF2: Mn as an emission layer and CaF2 as an insulating layer were also prepared and their EL properties were measured. EL intensity is observed to increase with the increase of substrate temperature. However, the breakdown voltage of the EL device is decreased at higher substrate temperatures. The mutual diffusion might take place in between CaF2 and ITO and causing breakdown of the device. This could be suppressed by an experiment in which SiO2 is inserted between the those two layers.
