title: GaAs/AlGaAs nanowire heterostructures studied by scanning tunneling microscopy.
abstract: We directly image the interior of GaAs/AlGaAs axial and radial nanowire heterostructures with atomic-scale resolution using scanning tunneling microscopy. We show that formation of monolayer sharp and smooth axial interfaces are possible even by vapor-phase epitaxy. However, we also find that instability of the ternary alloys formed in the Au seed fundamentally limits axial heterostructure control, inducing large segment asymmetries. We study radial core-shell nanowires, imaging even ultrathin submonolayer shells. We demonstrate how large twinning-induced morphological defects at the wire surfaces can be removed, ensuring the formation of wires with atomically flat sides.
authors.affiliation: Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden.
authors.forename: Lassana
authors.initials: L
authors.lastname: Ouattara
authors.forename: Anders
authors.initials: A
authors.lastname: Mikkelsen
authors.forename: Niklas
authors.initials: N
authors.lastname: Sköld
authors.forename: Jessica
authors.initials: J
authors.lastname: Eriksson
authors.forename: Thijs
authors.initials: T
authors.lastname: Knaapen
authors.forename: Elizabeta
authors.initials: E
authors.lastname: Cavar
authors.forename: Werner
authors.initials: W
authors.lastname: Seifert
authors.forename: Lars
authors.initials: L
authors.lastname: Samuelson
authors.forename: Edvin
authors.initials: E
authors.lastname: Lundgren
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D001152:Arsenicals / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D005708:Gallium / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D001152:Arsenicals; D046911:Macromolecular Substances; C043055:gallium arsenide; D005708:Gallium; D000535:Aluminum