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Inherent control of growth, morphology and defect formation in germanium nanowires
Biswas, Subhajit; Singha, Achintya; Morris, Michael A.; Holmes, Justin D.
The use of bimetallic alloy seeds for growing one-dimensional nanostructures has recently gained momentum among researchers. The compositional flexibility of alloys provides the opportunity to manipulate the chemical environment, reaction kinetics, and thermodynamic behavior of nanowire growth, in both the eutectic and the subeutectic regimes. This Letter describes for the first time the role of AuxAg1–x alloy nanoparticles in defining the growth characteristics and crystal quality of solid-seeded Ge nanowires via a supercritical fluid growth process. The enhanced diffusivity of Ge in the alloy seeds, compared to pure Ag seeds, and slow interparticle diffusion of the alloy nanoparticles allows the realization of high-aspect ratio nanowires with diameters below 10 nm, via a seeded bottom-up approach. Also detailed is the influence the alloyed seeds have on the crystalline features of nanowires synthesized from them, that is, planar defects. The distinctive stacking fault energies, formation enthalpies, and diffusion chemistries of the nanocrystals result in different magnitudes of {111} stacking faults in the seed particles and the subsequent growth of ⟨112⟩-oriented nanowires with radial twins through a defect transfer mechanism, with the highest number twinned Ge nanowires obtained using Ag0.75Au0.25 growth seeds. Employing alloy nanocrystals for intrinsically dictating the growth behavior and crystallinity of nanowires could open up the possibility of engineering nanowires with tunable structural and physical properties.
Keyword(s): AgxAu1−x alloy; Electron microscopy; Germanium; Nanowire; Supercritical fluid−solid−solid (SFSS) growth; Twin
Publication Date:
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Institution: University College Cork
Funder(s): Science Foundation Ireland; Higher Education Authority
Citation(s): Biswas, S., Singha, A., Morris, M. A. and Holmes, J. D. (2012) 'Inherent Control of Growth, Morphology, and Defect Formation in Germanium Nanowires', Nano Letters, 12(11), pp. 5654-5663. doi: 10.1021/nl302800u
Publisher(s): American Chemical Society (ACS)
File Format(s): application/pdf
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First Indexed: 2018-09-13 06:30:59 Last Updated: 2018-09-13 06:30:59