One-step fabrication of GeSn branched nanowires

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Doherty, Jessica
Biswas, Subhajit
McNulty, David
Downing, Clive
Raha, Sreyan
O'Regan, Colm
Singha, Achintya
O'Dwyer, Colm
Holmes, Justin D.
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American Chemical Society, ACS
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We report for the first time the self-catalyzed, single-step growth of branched GeSn nanostructures by a vapor–liquid–solid mechanism. These typical GeSn nanostructures consist of ⟨111⟩-oriented, Sn-rich (∼8 atom %) GeSn “branches” grown epitaxially on GeSn “trunks”, with a Sn content of ∼4 atom %. The trunks were seeded from Au0.80Ag0.20 nanoparticles followed by the catalytic growth of secondary branches (diameter ∼ 50 nm) from the excess of Sn on the sidewalls of the trunks, as determined by high-resolution electron microscopy and energy-dispersive X-ray analysis. The nanowires, with ⟨111⟩-directed GeSn branches oriented at ∼70° to the trunks, have no apparent defects or change in crystal structure at the trunk–branch interface; structural quality is retained at the interface with epitaxial crystallographic relation. The electrochemical performance of these highly ordered GeSn nanostructures was explored as a potential anode material for Li-ion batteries, due to their high surface-to-volume ratio and increased charge carrier pathways. The unique structure of the branched nanowires led to high specific capacities comparable to, or greater than, those of conventional Ge nanowire anode materials and Ge1–xSnx nanocrystals.
Nanowires , Germanium-tin , Branched nanostructure , Li-ion battery
erty, J., Biswas, S., McNulty, D., Downing, C., Raha, S., O’Regan, C., Singha, A., O’Dwyer, C. and Holmes, J. D. (2019) 'One-Step Fabrication of GeSn Branched Nanowires', Chemistry of Materials, 31(11), pp. 4016-4024. doi: 10.1021/acs.chemmater.9b00475
© 2019 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemistry of Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see