High strength, epitaxial nanotwinned Ag films

摘要

Epitaxial silver films with (111) and (110) orientations were deposited by magnetron sputtering onto silicon (111) and (110) substrates, respectively. High density growth twins with an average spacing of a few nanometers are observed in the (111) oriented films, with twin boundaries oriented normal to the growth direction. Twins are observed in the (110) oriented films with a much lower twin density, and the twin boundaries are oriented 60° from the growth direction. The epitaxial nanotwinned Ag (1 1 1) and (110) films have respective indentation hardness values of ~2 and 1 GPa. The influences of deposition parameters, stacking fault energy, and orientation of {1 1 1} planes on the formation of nanotwins are discussed.