The influence of interfaces on the formation of bubbles in He-ion-irradiated Cu/Mo nanolayers

Abstract The role of immiscible Cu/Mo interfaces on the formation of helium (He) bubbles in ion-irradiated Cu/Mo 5 nm multilayers is examined. Interfaces significantly enhance the critical He concentration above which bubbles, approximately 1 nm in diameter, are detected via through-focus imaging in a transmission electron microscope. He-to-vacancy ratio affects the formation and distribution of He bubbles. The diameter of He bubbles in Cu appears to be slightly larger than that in Mo. Keywords: ion irradiationCu/Mo multilayersHe bubblesinterfaces Acknowledgments The authors at TAMU acknowledge funding by the US Army Research Office – Materials Science Division, under contract no. W911NF-09-1-0223. NL and AM at LANL acknowledge support from LANL Lab Directed R&D (LDRD) and DOE, Office of Basic Energy Sciences, Energy Frontier Research Center. The authors are grateful for discussions with M.J. Demkowicz (MIT) and Q.M. Wei (at LANL).