Twin-Boundary Reduced Surface Diffusion on Electrically Stressed Copper Nanowires

Abstract

Surface diffusion is intimately correlated with crystal orientation and surface structure. Fast surface diffusion accelerates phase transformation and structural evolution of materials. Here, through in situ transmission electron microscopy observation, we show that a copper nanowire with dense nanoscale coherent twin-boundary (CTB) defects evolves into a zigzag configuration under electric-current driven surface diffusion. The hindrance at the CTB-intercepted concave triple junctions decreases the effective surface diffusivity by almost 1 order of magnitude. The energy barriers for atomic migration at the concave junctions and different faceted surfaces are computed using density functional theory. We proposed that such a stable zigzag surface is shaped not only by the high-diffusivity facets but also by the stalled atomic diffusion at the concave junctions. This finding provides a defect-engineering route to develop robust interconnect materials against electromigration-induced failures for nanoelectronic devices.

Twin Proliferation and Prolongation under Kinetic Control: Pd–Au Janus Icosahedra versus Pd@Au Core–Shell Starfishes

“…14,15 At a fast reduction rate, in contrast, nucleation of the second metal tends to occur from all available sites on the decahedral seeds, leading to symmetric growth. 16,17 Such symmetric growth can generate axial structures such as bidirectional pyramids and rods, or equatorial structures including core−shell/frame decahedra and core−shell starfishes. 18 In most cases, the resultant heterogeneous metal-based decahedral derivatives can only replicate the original twin boundaries in the seed, giving the final nanocrystal a similar quantity and length or even covering the twin regions to make them disappear at the distal ends.…”

“…At a slow reduction rate, nucleation of the second metal only occurs on a limited number of equivalent sites on the decahedral seeds, resulting in asymmetric growth . The asymmetric structures include axial growth-induced nanorods, nanopyramids, nanopencils, nanowires, and equatorial growth-induced lateral nanopyramids. , At a fast reduction rate, in contrast, nucleation of the second metal tends to occur from all available sites on the decahedral seeds, leading to symmetric growth. , Such symmetric growth can generate axial structures such as bidirectional pyramids and rods, or equatorial structures including core–shell/frame decahedra and core–shell starfishes. , …”

Watching Plasmon-Induced Nanoparticle Ostwald Ripening

“…Following its formation, a neck grows laterally across the interface between nanoparticles, producing a grain boundary. The structures of these grain boundaries are expected to impact the properties of the nanoparticle formed by coalescence − and are therefore worthy of study. We observed a variety of grain boundary structures (Figure ).…”