A Transmission Electron Microscopy Study of the Effect of Interfaces on Bubble Formation in He-Implanted Cu-Nb Multilayers
Magnetron sputtered thin films of Cu, Nb, and Cu-Nb multilayers with 2.5 and 5 nm nominal layer thickness were deposited on Si and implanted with 4He+ and 3He+ ions. Secondary ion mass spectroscopy and nuclear reaction analysis, respectively, were used to measure the 4He+ and 3He+ concentration profile with depth inside the films. Cross-sectional transmission electron microscopy was used to characterize the helium bubbles. Analysis of the contrast from helium bubbles in defocused transmission electron microscope images showed a minimum bubble diameter of 1.25 nm. While pure Cu and Nb films showed bubble contrast over the entire range of helium implantation, the multilayers exhibited bubbles only above a critical He concentration that increased almost linearly with decreasing layer thickness. The work shows that large amounts of helium can be trapped at incoherent interfaces in the form of stable, nanometer-size bubbles.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Materials at Irradiation and Mechanical Extremes (CMIME)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- 2008LANL1026
- OSTI ID:
- 1387016
- Journal Information:
- Microscopy and Microanalysis, Vol. 18, Issue 01; Related Information: CMIME partners with Los Alamos National Laboratory (lead); Carnegie Mellon University; University of Illinois, Urbana Champaign; Massachusetts Institute of Technology; University of Nebraska; ISSN 1431-9276
- Publisher:
- Microscopy Society of America (MSA)
- Country of Publication:
- United States
- Language:
- English
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