title: Structure, growth kinetics, and ledge flow during vapor-solid-solid growth of copper-catalyzed silicon nanowires.
abstract: We use real-time observations of the growth of copper-catalyzed silicon nanowires to determine the nanowire growth mechanism directly and to quantify the growth kinetics of individual wires. Nanowires were grown in a transmission electron microscope using chemical vapor deposition on a copper-coated Si substrate. We show that the initial reaction is the formation of a silicide, eta'-Cu(3)Si, and that this solid silicide remains on the wire tips during growth so that growth is by the vapor-solid-solid mechanism. Individual wire directions and growth rates are related to the details of orientation relation and catalyst shape, leading to a rich morphology compared to vapor-liquid-solid grown nanowires. Furthermore, growth occurs by ledge propagation at the silicide/silicon interface, and the ledge propagation kinetics suggest that the solubility of precursor atoms in the catalyst is small, which is relevant to the fabrication of abrupt heterojunctions in nanowires.
authors.affiliation: School of Materials Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: C-Y
authors.initials: CY
authors.lastname: Wen
authors.forename: M C
authors.initials: MC
authors.lastname: Reuter
authors.forename: J
authors.initials: J
authors.lastname: Tersoff
authors.forename: E A
authors.initials: EA
authors.lastname: Stach
authors.forename: F M
authors.initials: FM
authors.lastname: Ross
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning / Q000379:methods; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D053770:Nanowires / Q000737:chemistry*; D011312:Pressure; D012825:Silicon / Q000737:chemistry*; D013696:Temperature
chemical_list: D003300:Copper; D012825:Silicon