Rotational self-alignment of graphene seeds for nanoribbon synthesis on Ge(001) via chemical vapor deposition

Journal Article · Thu Sep 03 00:00:00 EDT 2020 · APL Materials

DOI:https://doi.org/10.1063/5.0013527· OSTI ID:1802805

Way, Austin J. ^[1]; Saraswat, Vivek ^[2]; Jacobberger, Robert M. ^[2]; Arnold, Michael S. ^[2]

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1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering; OSTI
2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering

The chemical vapor deposition of CH₄ on Ge(001) results in the anisotropic synthesis of graphene nanoribbons that are aligned to Ge$$\langle$$110$$\rangle$$ and have faceted armchair edges, sub-10 nm widths, and lengths greater than 100 nm. The utilization of small graphene seeds to initiate nanoribbon synthesis provides control over the nanoribbon placement and orientation. However, in order to exclusively grow nanoribbons and suppress the concomitant growth of lower aspect ratio crystals, it is imperative to control the crystallographic orientation of the seeds with respect to the Ge lattice. Here, we demonstrate that when seeds are less than 18 nm in diameter, they are able to rotate upon annealing at 910 °C prior to nanoribbon synthesis. The effect of this rotation on the resulting nanoribbons’ orientation is characterized as a function of the diameter and initial crystallographic orientation of the seeds. The seeds preferentially rotate to an orientation in which an armchair direction of their lattice is parallel to Ge$$\langle$$110$$\rangle$$—subsequently maximizing the anisotropy in growth kinetics. By exploiting this seed rotation phenomenon, we demonstrate the fabrication of seamless nanoribbon meshes and gain understanding that will affect future efforts to create arrays of unidirectionally aligned nanoribbons.

• Research Organization: Univ. of Wisconsin, Madison, WI (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0016007
• OSTI ID: 1802805
• Alternate ID(s): OSTI ID: 1657644
• Journal Information: APL Materials, Journal Name: APL Materials Journal Issue: 9 Vol. 8; ISSN 2166-532X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Chemical vapor deposition
Electrical properties and parameters
Electron-beam lithography
Graphene
Mask patterning
Materials properties
Nanoribbons
Semiconductors
Semimetals