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Preferred growth direction of III-V nanowires on differently oriented Si substrates

zeng, H; Yu, X; Fonseka, HA; Boras, G; Jurczak, P; Wang, T; Sanchez, AM; (2020) Preferred growth direction of III-V nanowires on differently oriented Si substrates. Nanotechnology , 31 (47) , Article 475708. 10.1088/1361-6528/abafd7. (In press). Green open access

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Abstract

One of the nanowire (NW) characteristics is its preferred elongation direction. Here, we investigated the impact of Si substrate crystal orientation on the growth direction of GaAs NWs. We first studied the self-catalyzed GaAs NW growth on Si (111) and Si (001) substrates. SEM observations show GaAs NWs on Si (001) are grown along four <111> directions without preference on one or some of them. This non-preferential NW growth on Si (001) is morphologically in contrast to the extensively reported vertical <111> preferred GaAs NW growth on Si (111) substrates. We propose a model based on the initial condition of an ideal Ga droplet formation on Si substrates and the surface free energy calculation which takes into account the dangling bond surface density for different facets. This model provides further understanding of the different preferences in the growth of GaAs NWs along selected <111> directions depending on the Si substrate orientation. To verify the prevalence of the model, NWs were grown on Si (311) substrates. The results are in good agreement with the three-dimensional mapping of surface free energy by our model. This general model can also be applied to predictions of NW preferred growth directions by the vapor-liquid-solid growth mode on other group IV and III–V substrates.

Type: Article
Title: Preferred growth direction of III-V nanowires on differently oriented Si substrates
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/1361-6528/abafd7
Publisher version: https://doi.org/10.1088/1361-6528/abafd7
Language: English
Additional information: Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. http://creativecommons.org/licenses/by/4.0/
Keywords: III-V nanowires, MBE, surface free energy, growth direction
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Electronic and Electrical Eng
URI: https://discovery.ucl.ac.uk/id/eprint/10108958
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