NANOSCIENCE A new twist on nanowire growth leads to stunning structures

Abstract

Nanowires don’t grow on trees, but they can grow into tree-shaped objects, such as this stunning lead sulfide structure created by chemistry professor Song Jin’s group at the University of Wisconsin ( Science , DOI: 10.1126/science.1157131). While most nanowires sprout from catalyst seeds, the “trunks” of Jin’s nanotrees form via a new mechanism of nanowire growth that’s driven by screwlike dislocations in the PbS crystal. These defects, Jin says, create “self-perpetuating spiral steps for atoms to settle on and cause the crystal lattice to twist.” Nanowire “branches” grow off this twisting central rod via the more common catalyst-based mechanism. “When this new mechanism is well understood and well controlled, more elaborate and complex nanostructures can be rationally prepared, many of which could have interesting applications,” Jin says. ...