The influence of residual O-2 gas in vacuum on the structural and luminescent properties of ZnF2:Mn thin films

The relationship between the structural and photoluminescent properties and the preparation conditions of ZnF2:Mn thin films deposited by electron beam evaporation has been investigated. It was found that a part of the ZnF2:Mn film deposited at a substrate temperature higher than 300 degrees C under about 10(-6) Ton is oxidized to ZnO by residual O-2 gas on the substrate. The formation of ZnO was confirmed by X-ray diffraction, spectral transmission, AES analysis and photoluminescence. This oxidation process could nor be observed even at 500 degrees C if the pressure is lowered to 10(-8) Torr, It was also found that the crystallinity was improved with increasing substrate temperature.