Adhikari, Hemant and Marshall, Ann F. and Goldthorpe, Irene A. and Chidsey, Christopher E. D. and McIntyre, Paul C. (2007) Metastability of Au-Ge liquid nanocatalysts: Ge vapor-liquid-solid nanowire growth far below the bulk eutectic temperature. ACS NANO, 1 (5). pp. 415-422.
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Official URL: http://dx.doi.org/10.1021/nn7001486
The vapor-liquid-solid mechanism of nanowire (NW) growth requires the presence of a liquid at one end of the wire; however, Au-catalyzed Ge nanowire growth by chemical vapor deposition can occur at similar to 100 degrees C below the bulk Au-Ge eutectic. In this paper, we investigate deep sub-eutectic stability of liquid Au-Ge catalysts on Ge NWs quantitatively, both theoretically and experimentally. We construct a binary Au-Ge phase diagram that is valid at the nanoscale and show that equilibrium arguments, based on capillarity, are inconsistent with stabilization of Au-Ge liquid at deep sub-eutectic temperatures, similar to those used in Ge NW growth. Hot-stage electron microscopy and X-ray diffraction are used to test the predictions of nanoscale phase equilibria. In addition to Ge supersaturation of the Au-Ge liquid droplet, which has recently been invoked as an explanation for deep sub-eutectic Ge NW growth, we find evidence of a substantial kinetic barrier to Au solidification during cooling below the nanoscale Au-Ge eutectic temperature.
|Uncontrolled Keywords:||sub-eutectic growth; phase diagram; nanowires; germanium; nanocatalyst; TEM; Au-Ge|
|Subjects:||Material Science > Nanochemistry|
Material Science > Nanostructured materials
|Deposited By:||Anuj Seth|
|Deposited On:||17 Dec 2008 15:38|
|Last Modified:||17 Dec 2008 15:38|
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