Thermodynamic analysis for the size-dependence of Si1-xGex nanowire composition grown by a vapor-liquid-solid method

A fundamental thermodynamic approach for the size dependence of the Si1-xGex alloy nanowire composition grown by a vapor-liquid-solid method is proposed. It is shown that the experimentally observed size dependence of the Si1-xGex alloy nanowire composition originates from the capillarity effect. The direct effect of the capillarity on the composition of liquid droplets is clarified and rationalized based on the solution thermodynamics. The present approach can be a starting point for more sophisticated and quantitative studies to predict and control the composition of alloy nanowires synthesized by similar methods. (C) 2008 Elsevier Ltd. All rights reserved.