Type

Journal Article

Authors

Justin D. Holmes
Nikolay Petkov
John J. Boland
Soon Jung Jung
Curtis O'Kelly
Subhajit Biswas
Colm O'Regan

Subjects

Physics

Topics
nanowires ge nanowires nanoelectromechanical devices semiconductor nanowires supersaturation growth rate vapor liquid solid growth anodes nucleation phase diagram germanium silicon nanowires

Engineering the growth of germanium nanowires by tuning the supersaturation of Au/Ge binary alloy catalysts (2013)

Abstract The synthesis of Ge nanowires with very high-aspect ratios (greater than 1000) and uniform crystal growth directions is highly desirable, not only for investigating the fundamental properties of nanoscale materials but also for fabricating integrated functional nanodevices. In this article, we present a unique approach for manipulating the supersaturation, and thus the growth kinetics, of Ge nanowires using Au/Ge bilayer films. Ge nanowires were synthesized on substrates consisting of two parts: a Au film on one-half of a Si substrate and a Au/Ge bilayer film on the other half of the substrate. Upon annealing the substrate, Au and Au/Ge binary alloy catalysts were formed on both the Au and Au/Ge-sides of the substrates, respectively, under identical conditions. The mean lengths of Ge nanowires produced were found to be significantly longer on the Au/Ge bilayer side of the substrate compared to the Au-coated side, as a result of a reduced incubation time for nucleation on the bilayer side. The mean length and growth rate on the bilayer side (with a 1 nm Ge film) was found to be 5.5 ± 2.3 μm and 3.7 × 10–3 μm s–1, respectively, and 2.7 ± 0.8 μm and 1.8 × 10–3 μm s–1 for the Au film. Additionally, the lengths and growth rates of the nanowires further increased as the thickness of the Ge layer in the Au/Ge bilayer was increased. In-situ TEM experiments were performed to probe the kinetics of Ge nanowire growth from the Au/Ge bilayer substrates. Diffraction contrast during in situ heating of the bilayer films clarified the fact that thinner Ge films, that is, lower Ge concentration, take longer to alloy with Au than thicker films. Phase separation was also more significant for thicker Ge films upon cooling. The use of binary alloy catalyst particles, instead of the more commonly used elementary metal catalyst, enabled the supersaturation of Ge during nanowire growth to be readily tailored, offering a unique approach to producing very long high aspect ratio nanowires.
Collections Ireland -> University College Cork -> Materials Chemistry and Analysis Group
Ireland -> University College Cork -> College of Science, Engineering and Food Science
Ireland -> University College Cork -> Tyndall National Institute
Ireland -> University College Cork -> Micro-Nanoelectronics Centre
Ireland -> University College Cork -> Chemistry
Ireland -> University College Cork -> Materials Chemistry and Analysis Group - Journal articles
Ireland -> University College Cork -> Chemistry - Journal Articles
Ireland -> University College Cork -> Research Institutes and Centres

Full list of authors on original publication

Justin D. Holmes, Nikolay Petkov, John J. Boland, Soon Jung Jung, Curtis O'Kelly, Subhajit Biswas, Colm O'Regan

Experts in our system

1
Justin D. Holmes
University College Cork
Total Publications: 287
 
2
Nikolay Petkov
University College Cork
Total Publications: 64
 
3
John J Boland
Trinity College Dublin
Total Publications: 82
 
4
Subhajit Biswas
University College Cork
Total Publications: 43
 
5
Colm O'Regan
University College Cork
Total Publications: 16