Surface Crystallization of Liquid Au-Si and Its Impact on Catalysis

Federico Panciera; Jerry Tersoff; Andrew D Gamalski; Mark C Reuter; Dmitri Zakharov; Eric A Stach; Stephan Hofmann; Frances M Ross

doi:10.1002/adma.201806544

Surface Crystallization of Liquid Au-Si and Its Impact on Catalysis

Adv Mater. 2019 Feb;31(5):e1806544. doi: 10.1002/adma.201806544. Epub 2018 Dec 5.

Authors

Federico Panciera^{1

2}, Jerry Tersoff², Andrew D Gamalski³, Mark C Reuter², Dmitri Zakharov³, Eric A Stach³, Stephan Hofmann¹, Frances M Ross²

Affiliations

¹ Department of Engineering, University of Cambridge, 9 J. J. Thomson Avenue, Cambridge, CB3 0FA, UK.
² IBM T. J. Watson Research Center, Yorktown Heights, NY, 10598, USA.
³ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY, 11973, USA.

PMID: 30516864
DOI: 10.1002/adma.201806544

Abstract

In situ transmission electron microscopy reveals that an atomically thin crystalline phase at the surface of liquid Au-Si is stable over an unexpectedly wide range of conditions. By measuring the surface structure as a function of liquid temperature and composition, a simple thermodynamic model is developed to explain the stability of the ordered phase. The presence of surface ordering plays a key role in the pathway by which the Au-Si eutectic solidifies and also dramatically affects the catalytic properties of the liquid, explaining the anomalously slow growth kinetics of Si nanowires at low temperature. A strategy to control the presence of the surface phase is discussed, using it as a tool in designing strategies for nanostructure growth.

Keywords: 2D crystals; in situ transmission electron microscopy; metastable phases; nanowires; surface ordering.

Abstract

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