title: Dislocation-driven nanowire growth and Eshelby twist.
abstract: Hierarchical nanostructures of lead sulfide nanowires resembling pine trees were synthesized by chemical vapor deposition. Structural characterization revealed a screwlike 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 the 110 directions having an estimated magnitude of 6 +/- 2 angstroms for the screw component. The results confirm the Eshelby theory of dislocations, and the proposed nanowire growth mechanism could be general to many materials.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Bierman
authors.forename: Y K Albert
authors.initials: YK
authors.lastname: Lau
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kvit
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Schmitt
authors.forename: Song
authors.initials: S
authors.lastname: Jin