Helium implantation effects on the compressive response of Cu nanopillars.

A fabrication methodology for 120 nm-diameter, <111>-oriented single crystalline Cu nanopillars which are uniformly implanted with helium is described. Uniaxial compression experiments reveal that their yield strength is 30% higher than that of their unimplanted counterparts. This study sheds light on the fundamental understanding of the deformation mechanism of irradiated metallic nanocrystals, and has important implications for the interplay between irradiation-induced defects and the external sample dimensions in the nanoscale.