Submitted on February 29, 2008
Accepted on April 16, 2008
Dislocation-Driven Nanowire Growth and Eshelby Twist
Matthew J. Bierman 1
, Y. K. Albert Lau 1, Alexander V. Kvit 2, Andrew L. Schmitt 1, Song Jin 1*
1 Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI 53706, USA.
2 Materials Science Center, University of Wisconsin–Madison, 1509 University Avenue, Madison, WI 53706, USA.
* To whom correspondence should be addressed.
Song Jin , E-mail: jin{at}chem.wisc.edu
These authors contributed equally to this work.
Hierarchical nanostructures of lead sulfide nanowires resembling pine trees were synthesized via chemical vapor deposition. Structural characterization reveals a screw-like dislocation in the nanowire trunks with helically rotating epitaxial branch nanowires. It is suggested that the screw component of an axial dislocation provides the self-perpetuating steps to enable one-dimensional crystal growth, in contrast to mechanisms that require metal catalysts. The rotating trunks and branches are the consequence of the Eshelby twist of screw dislocations with a dislocation Burgers vector along <110> directions with an estimated magnitude of 6 ± 2 Å for the screw component. The results confirm the Eshelby theory of dislocations and the proposed nanowire growth mechanism could be general to many materials.
