Taper-free and vertically oriented Ge nanowires on Ge/Si substrates grown by a two-temperature process
Article
Article Title | Taper-free and vertically oriented Ge nanowires on Ge/Si substrates grown by a two-temperature process |
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ERA Journal ID | 34352 |
Article Category | Article |
Authors | Kim, Jung Hyuk (Author), Moon, So Ra (Author), Yoon, Hyun Sik (Author), Jung, Jae Hun (Author), Kim, Yong (Author), Chen, Zhi Gang (Author), Zou, Jin (Author), Choi, Duk Yong (Author), Joyce, Hannah J. (Author), Gao, Qiang (Author), Tan, H. Hoe (Author) and Jagadish, Chennupati (Author) |
Journal Title | Crystal Growth and Design |
Journal Citation | 12 (1), pp. 135-141 |
Number of Pages | 7 |
Year | 2012 |
Place of Publication | United States |
ISSN | 1528-7483 |
1528-7505 | |
Digital Object Identifier (DOI) | https://doi.org/10.1021/cg2008914 |
Web Address (URL) | http://pubs.acs.org/doi/abs/10.1021/cg2008914 |
Abstract | Taper-free and vertically oriented Ge nanowires were grown on Si (111) substrates by chemical vapor deposition with Au nanoparticle catalysts. To achieve vertical nanowire growth on the highly lattice mismatched Si substrate, a thin Ge buffer layer was first deposited, and to achieve taper-free nanowire growth, a two-temperature process was employed. The two-temperature process consisted of a brief initial base growth step at high temperature followed by prolonged growth at lower temperature. Taper-free and defect-free Ge nanowires grew successfully even at 270 °C, which is 90 °C lower than the bulk eutectic temperature. The yield of vertical and taper-free nanowires is over 90%, comparable to that of vertical but tapered nanowires grown by the conventional one-temperature process. This method is of practical importance and can be reliably used to develop novel nanowire-based devices on relatively cheap Si substrates. Additionally, we observed that the activation energy of Ge nanowire growth by the two-temperature process is dependent on Au nanoparticle size. The low activation energy (∼5 kcal/mol) for 30 and 50 nm diameter Au nanoparticles suggests that the decomposition of gaseous species on the catalytic Au surface is a rate-limiting step. A higher activation energy (∼14 kcal/mol) was determined for 100 nm diameter Au nanoparticles which suggests that larger Au nanoparticles are partially solidified and that growth kinetics become the rate-limiting step. |
Keywords | Au nanoparticle; Au surfaces; Defect-free; Eutectic temperature; Gaseous species; Growth steps; High temperature; Lattice-mismatched; Low-activation energy; Nanowire growth; Practical importance; Rate-limiting steps; Si substrates; Si(111) substrate; Two-temperature; Coating Materials; Coating Techniques; Chemical Products Generally; Chemistry; Solid State Physics; Nanotechnology; Electric and Magnetic Materials; |
ANZSRC Field of Research 2020 | 401699. Materials engineering not elsewhere classified |
Public Notes | Files associated with this item cannot be displayed due to copyright restrictions. |
Byline Affiliations | Dong-A University, Korea |
University of Queensland | |
Australian National University | |
University of Oxford, United Kingdom | |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q418y/taper-free-and-vertically-oriented-ge-nanowires-on-ge-si-substrates-grown-by-a-two-temperature-process
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