Growth and analysis of the tetragonal (ST12) germanium nanowires

Garcia-Gil, Adriá; Biswas, Subhajit; Roy, Ahin; Saladukh, Dzianis; Raha, Sreyan; Blon, Thomas; Conroy, Michele; Nicolosi, Valeria; Singha, Achintya; Lacroix, Lise-Marie; Holmes, Justin D.

Growth and analysis of the tetragonal (ST12) germanium nanowires

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Garcia et al_SI.pdf(1.32 MB)

Supplementary Information

Date

2022-01-17

Authors

Garcia-Gil, Adriá

Biswas, Subhajit

Roy, Ahin

Saladukh, Dzianis

Raha, Sreyan

Blon, Thomas

Conroy, Michele

Nicolosi, Valeria

Singha, Achintya

Lacroix, Lise-Marie

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Publisher

Royal Society of Chemistry

Published Version

10.1039/d1nr07669h

Abstract

New semiconducting materials, such as state-of-the-art alloys, engineered composites and allotropes of well-established materials can demonstrate unique physical properties and generate wide possibilities for a vast range of applications. Here we demonstrate, for the first time, the fabrication of a metastable allotrope of Ge, tetragonal germanium (ST12-Ge), in nanowire form. Nanowires were grown in a solvothermal-like single-pot method using supercritical toluene as a solvent, at moderate temperatures (290–330 °C) and a pressure of ∼48 bar. One-dimensional (1D) nanostructures of ST12-Ge were achieved via a self-seeded vapour–liquid–solid (VLS)-like paradigm, with the aid of an in situ formed amorphous carbonaceous layer. The ST12 phase of Ge nanowires is governed by the formation of this carbonaceous structure on the surface of the nanowires and the creation of Ge–C bonds. The crystalline phase and structure of the ST12-Ge nanowires were confirmed by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The nanowires produced displayed a high aspect ratio, with a very narrow mean diameter of 9.0 ± 1.4 nm, and lengths beyond 4 μm. The ST12-Ge nanowire allotrope was found to have a profound effect on the intensity of the light emission and the directness of the bandgap, as confirmed by a temperature-dependent photoluminescence study.

Keywords

Tetragonal (ST12) germanium nanowires

Citation

Garcia-Gil, A., Biswas, S., Roy, A., Saladukh, D., Raha, S., Blon, T., Conroy, M., Nicolosi, V., Singha, A., Lacroix, L.-M. and Holmes, J. D. (2022) 'Growth and analysis of the tetragonal (ST12) germanium nanowires', Nanoscale, 14(5), pp. 2030-2040. doi: 10.1039/d1nr07669h