[SY-N3] Kinetics of Fivefold-Twinned Nanowire Growth
Invited
There has been significant emphasis recently on the synthesis of fivefold-twinned Ag and Cu nanowires, which are considered to be excellent candidates for transparent conductors in flexible and stretchable electronic devices. A fundamental understanding of nanowire growth is important in achieving optimal syntheses. Nanowires grow from fivefold-twinned seeds and our work shows that likely shapes for these structures include {111} end facets and “notches”, {100} side facets, and {110} facets between the notches and the ends. We find that the density of islands on the {111} facets of growing wires is lower than that on {100} facets and that islands are likely to nucleate on {111} facets near {110}-{111} facet boundaries. Our climbing-image nudged-elastic band calculations of diffusion barriers based on embedded-atom method potentials indicate that diffusion in the {111} notches and on the {110} “steps” is significantly faster than diffusion on {100} facets. Thus, these structures become “superhighways” that channel atom diffusion to the wire ends to increase wire aspect ratios. Small islands facilitate trapping of atoms on {111} facets. We use finite Markov chains to model nanowire growth and to predict net atom fluxes from nanowire sides to the ends. These simulations predict anisotropic nanowires similar to those seen experimentally.