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Non-equilibrium induction of tin in germanium: towards direct bandgap Ge1-xSnx nanowires
Biswas, Subhajit; Doherty, Jessica; Saladukha, Dzianis; Ramasse, Quentin; Majumdar, Dipanwita; Upmanyu, Moneesh; Singha, Achintya; Ochalski, Tomasz J.; Morris, Michael A.; Holmes, Justin D.
The development of non-equilibrium group IV nanoscale alloys is critical to achieving new functionalities, such as the formation of a direct bandgap in a conventional indirect bandgap elemental semiconductor. Here, we describe the fabrication of uniform diameter, direct bandgap Ge1-xSnx alloy nanowires, with a Sn incorporation up to 9.2[thinsp]at.%, far in excess of the equilibrium solubility of Sn in bulk Ge, through a conventional catalytic bottom-up growth paradigm using noble metal and metal alloy catalysts. Metal alloy catalysts permitted a greater inclusion of Sn in Ge nanowires compared with conventional Au catalysts, when used during vapour-liquid-solid growth. The addition of an annealing step close to the Ge-Sn eutectic temperature (230[thinsp][deg]C) during cool-down, further facilitated the excessive dissolution of Sn in the nanowires. Sn was distributed throughout the Ge nanowire lattice with no metallic Sn segregation or precipitation at the surface or within the bulk of the nanowires. The non-equilibrium incorporation of Sn into the Ge nanowires can be understood in terms of a kinetic trapping model for impurity incorporation at the triple-phase boundary during growth.
Keyword(s): Physical sciences; Materials science; Nanotechnology; Physical chemistry
Publication Date:
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Institution: University College Cork
Funder(s): Science Foundation Ireland
Citation(s): Biswas, S., Doherty, J., Saladukha, D., Ramasse, Q., Majumdar, D., Upmanyu, M., Singha, A., Ochalski, T., Morris, M. A. and Holmes, J. D. (2016) 'Non-equilibrium induction of tin in germanium: towards direct bandgap Ge1−xSnx nanowires', 7, 11405. doi: 10.1038/ncomms11405
Publisher(s): Nature Publishing Group
File Format(s): application/pdf
Related Link(s):
First Indexed: 2016-07-13 05:54:18 Last Updated: 2017-07-06 05:32:06