Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties
In this study, epitaxial graphene layers of cm<sup>2</sup> sizes were grown on silicon carbide (SiC) substrates by high-temperature sublimation. The behavior of the two crystallographic SiC-polar faces and its effect on the growth mechanism of graphene layers and their properties were in...
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MDPI AG
2023-01-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/13/2/189 |
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| author | Stefan A. Pitsch R. Radhakrishnan Sumathi |
| author_facet | Stefan A. Pitsch R. Radhakrishnan Sumathi |
| author_sort | Stefan A. Pitsch |
| collection | DOAJ |
| description | In this study, epitaxial graphene layers of cm<sup>2</sup> sizes were grown on silicon carbide (SiC) substrates by high-temperature sublimation. The behavior of the two crystallographic SiC-polar faces and its effect on the growth mechanism of graphene layers and their properties were investigated. Crystallographic structural differences observed in AFM studies were shown to cause disparities in the electrical conductivity of the grown layers. On the silicon-polar (Si-polar) face of SiC, the graphene formation occurred in spike-like structures that originated orthogonally from atomic steps of the substrate and grew outwards in the form of 2D nucleation with a fairly good surface coverage over time. On the carbon-polar (C-polar) face, a hexagonal structure already formed at the beginning of the growth process. On both polar faces, the known process of step-bunching promoted the formation of nm-scale structural obstacles. Such a step-bunching effect was found to be more pronounced on the C-polar face. These 2D-obstacles account for a low probability of a complete nano-sheet formation, but favor 2D-structures, comparable to graphene nanoribbons. The resulting direction-dependent anisotropic behavior in electrical conductivity measured by four-point probe method mainly depends on the height and spacing between these structural-obstacles. The anisotropy becomes less prudent as and when more graphene layers are synthesized. |
| first_indexed | 2024-03-11T08:59:08Z |
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| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-11T08:59:08Z |
| publishDate | 2023-01-01 |
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| spelling | doaj.art-97983609218b425e9908af49575ac35e2023-11-16T19:54:42ZengMDPI AGCrystals2073-43522023-01-0113218910.3390/cryst13020189Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical PropertiesStefan A. Pitsch0R. Radhakrishnan Sumathi1Applied Crystallography and Materials Science Section, Department of Earth and Environmental Sciences, Ludwig-Maximilians-University (LMU), Theresienstrasse 41, D-80333 Munich, GermanyApplied Crystallography and Materials Science Section, Department of Earth and Environmental Sciences, Ludwig-Maximilians-University (LMU), Theresienstrasse 41, D-80333 Munich, GermanyIn this study, epitaxial graphene layers of cm<sup>2</sup> sizes were grown on silicon carbide (SiC) substrates by high-temperature sublimation. The behavior of the two crystallographic SiC-polar faces and its effect on the growth mechanism of graphene layers and their properties were investigated. Crystallographic structural differences observed in AFM studies were shown to cause disparities in the electrical conductivity of the grown layers. On the silicon-polar (Si-polar) face of SiC, the graphene formation occurred in spike-like structures that originated orthogonally from atomic steps of the substrate and grew outwards in the form of 2D nucleation with a fairly good surface coverage over time. On the carbon-polar (C-polar) face, a hexagonal structure already formed at the beginning of the growth process. On both polar faces, the known process of step-bunching promoted the formation of nm-scale structural obstacles. Such a step-bunching effect was found to be more pronounced on the C-polar face. These 2D-obstacles account for a low probability of a complete nano-sheet formation, but favor 2D-structures, comparable to graphene nanoribbons. The resulting direction-dependent anisotropic behavior in electrical conductivity measured by four-point probe method mainly depends on the height and spacing between these structural-obstacles. The anisotropy becomes less prudent as and when more graphene layers are synthesized.https://www.mdpi.com/2073-4352/13/2/1892D materialsgraphenesilicon carbidesublimation growthsurface morphologiesstep-bunching |
| spellingShingle | Stefan A. Pitsch R. Radhakrishnan Sumathi Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties Crystals 2D materials graphene silicon carbide sublimation growth surface morphologies step-bunching |
| title | Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties |
| title_full | Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties |
| title_fullStr | Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties |
| title_full_unstemmed | Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties |
| title_short | Effect of Polar Faces of SiC on the Epitaxial Growth of Graphene: Growth Mechanism and Its Implications for Structural and Electrical Properties |
| title_sort | effect of polar faces of sic on the epitaxial growth of graphene growth mechanism and its implications for structural and electrical properties |
| topic | 2D materials graphene silicon carbide sublimation growth surface morphologies step-bunching |
| url | https://www.mdpi.com/2073-4352/13/2/189 |
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