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

C Y. Wen, Purdue University - Main Campus
M C. Reuter, IBM Corp.
J Tersoff, IBM Corp.
E A. Stach, Birck Nanotechnology Center and School of Materials Engineering, Purdue University
F M. Ross, IBM Corp.

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'-Cu3Si, and that this solid silicide remains on the wire rips 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.

Discipline(s)

Engineering | Nanoscience and Nanotechnology