Catalytic growth of nanowires: Vapor-liquid-solid, vapor-solid-solid, solution-liquid-solid and solid-liquid-solid growth

Catalytic growth is a powerful tool to form a variety of wire (whisker) like structures with diameters ranging from just a few nanometres to the millimetre range. A range of phases (gas, solid, liquid, solution and supercritical fluid) have been used for the feeder phase, i.e. the source of material to be incorporated into the nanowire. Solid, liquid, eutectic, alloy and metastable phases have all been invoked to explain the structure of the catalytic particle. Rather than focussing on the differences that lead to the proliferation of an alphabet soup of names for the various growth techniques, this review attempts to focus on the similarities between all of these catalytic growth processes in an attempt to help stimulate a more universal understanding of the phenomenon. The review begins with a precis of the materials from which nanowires have been formed and then proceeds to a discussion of mechanistic aspects. (c) 2007 Elsevier Ltd. All rights reserved.