Orientation of vacuum–evaporated BaF2 films in the presence of nitrogen

Abstract

BaF 2 films were vacuum deposited on borosilicate glass substrates at room and higher temperatures. The films were polycrystalline with different orientations. Introduction of N2 at 3×10−4 mbar pressure during evaporation resulted in a dramatic improvement in orientation along a given direction, which itself was a function of the substrate temperature. Thus, at room temperature, the orientation was along the (111) direction, while at 100 °C it was along the (220) direction.