Polyhedral Holes in Evaporated AuCu Films

A transmission electron microscope study of ordered (001) films of Au-50 at. % Cu made by evaporation in vacuo onto cleaved rocksalt at 400°C showed (a) the presence of a 6 sided roughly hexagonal single crystal area in the film about 2 μ across apparently surrounded by polycrystals, the 3 pairs of sides being nearly parallel to [1̄00],[1̄20], and [1̄1̄0], respectively, (b) streaks within this crystal interpretable as twins on (111), (c) holes through the film tended within this crystal to be polyhedral, developing sides parallel to 〈100〉 and 〈110〉. The latter observation indicates that the effective supersaturation during evaporation is relatively low.