title: Electrically active screw dislocations in helical ZnO and Si nanowires and nanotubes.
abstract: While the presence of axial screw dislocations in helical nanowires and nanotubes is known to be due to the growth process, their effect on the electronic properties remains unexplored. Relying on objective molecular dynamics simulations coupled to density functional tight-binding models for ZnO and Si, and supporting density functional theory calculations, we predict significant screw-dislocation-induced band gap modifications in both materials. The effect originates in the highly distorted cores and should be present at radii larger than those considered in our simulations (maximum ∼2 nm) as well as in other materials. The observed band gap dependences on the size of the Burgers vector and wall thickness could motivate new strategies for growing, via the screw dislocation mechanism, stable nanostructures with desired band gaps.
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States.
authors.forename: Evgeniya
authors.initials: E
authors.lastname: Akatyeva
authors.forename: Liangzhi
authors.initials: L
authors.lastname: Kou
authors.forename: Ilia
authors.initials: I
authors.lastname: Nikiforov
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenheim
authors.forename: Traian
authors.initials: T
authors.lastname: Dumitrică
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D004574:Electromagnetic Fields; D046911:Macromolecular Substances / Q000737:chemistry / Q000528:radiation effects; D008422:Materials Testing; D008956:Models, Chemical; D008968:Molecular Conformation / Q000528:radiation effects; D056004:Molecular Dynamics Simulation; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry* / Q000528:radiation effects; D013499:Surface Properties; D015034:Zinc Oxide / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D046911:Macromolecular Substances; D015034:Zinc Oxide; D012825:Silicon