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Fabrice Oehler

Study and analysis of the catalyzed growth mechanisms of silicon nanowires obtained by Chemical Vapour Deposition

Published on 6 July 2010


Thesis presented July 06, 2010

Abstract:
Silicon nanowires hold many technological promises but require a strict dimension and shape control. Growth of silicon nanowires can be performed by Chemical Vapour Deposition using gold catalysts and silicon precursors, with and without chlorine. We identify here the roles of chlorine on the growth stability and the wire morphology. The silicon surface is shown to chlorinate in the presence of chlorine, which reduces the gold migration on the wire surface without changing the (axial) growth kinetics. Growth conditions that use chlorine are then suitable for the stable growth of small diameter silicon nanowire down to 20 nm whereas chlorine-free growth can be unstable. The effect of chlorine is also visible on the wire sidewalls, where the facets evolution depends on the radial growth speed. Passivation of the surfaces is then a key point to stabilize the growth of wires and to control their morphology.

Keywords:
silicon, nanowire, growth, catalyst, chlorine, gold

On-line thesis.