A new twist on nanowire growth leads to stunning structures

by Bethany Halford

Science ©2008

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.

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