ANOMALOUS DEUTERIUM TRAPPING IN EVAPORATED IRON FILMS STUDIED BY POSITRON-ANNIHILATION

Forward recoil energy spectroscopy showed that thin, evaporated Fe films trap anomalously large quantities of deuterium. Positron annihilation was used to investigate how the film microstructure influenced this trapping. Polycrystalline films trapped more deuterium and contained more open volume defects than single-crystal films. Annealing reduced both trap and open volume defect concentrations. These results strongly suggest that coalescence voids produced during the thin-film deposition were the sites for the trapping of deuterium.