Structure, Growth Kinetics, and Ledge Flow during Vapor−Solid−Solid Growth of Copper-Catalyzed Silicon Nanowires

• Published in: Nano letters 2010-02, Vol.10 (2), p.514-519
• Main Authors: Wen, C.-Y, Reuter, M. C, Tersoff, J, Stach, E. A, Ross, F. M
• Format: Article
• Language: English
• Subjects: Catalysis; Catalytic methods; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Copper - chemistry; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Kinetics; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Methods of nanofabrication; Microscopy, Electron, Scanning - methods; Microscopy, Electron, Transmission - methods; Nanocrystalline materials; Nanoparticles - chemistry; Nanoscale materials and structures: fabrication and characterization; Nanotechnology - methods; Nanowires - chemistry; Physics; Pressure; Quantum wires; Silicon - chemistry; Temperature
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl903362y

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, η′-Cu3Si, 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.