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://pubs.acs.org/doi/abs/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 ∼100 °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:||Analytical Science > Microscopy and probe methods|
Material Science > Nanofabrication processes and tools
|Deposited By:||Farnush Anwar|
|Deposited On:||03 Dec 2008 13:50|
|Last Modified:||20 Jan 2009 16:16|
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