| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Improvement of Metal-Graphene Ohmic Contact Resistance in Bilayer Epitaxial Graphene Devices |
| HE Ze-Zhao1,2, YANG Ke-Wu1,2, YU Cui2, LI Jia2, LIU Qing-Bin2, LU Wei-Li2, FENG Zhi-Hong2**, CAI Shu-Jun2 |
1School of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300130
2National Key Laboratory of ASIC, Hebei Semiconductor Research Institute, Shijiazhuang 050051
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| Cite this article: |
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HE Ze-Zhao, YANG Ke-Wu, YU Cui et al 2015 Chin. Phys. Lett. 32 117204 |
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Abstract We report on an improved metal-graphene ohmic contact in bilayer epitaxial graphene on a SiC substrate with contact resistance below 0.1 Ω?mm. Monolayer and bilayer epitaxial graphenes are prepared on a 4H-SiC substrate in this work. Their contact resistances are measured by a transfer length method. An improved photoresist-free device fabrication method is used and is compared with the conventional device fabrication method. Compared with the monolayer graphene, the contact resistance Rc of bilayer graphene improves from an average of 0.24 Ω?mm to 0.1 Ω?mm. Ohmic contact formation mechanism analysis by Landauer's approach reveals that the obtained low ohmic contact resistance in bilayer epitaxial graphene is due to their high carrier density, high carrier transmission probability, and p-type doping introduced by contact metal Au.
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Received: 10 August 2015
Published: 01 December 2015
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| PACS: |
72.80.Vp
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(Electronic transport in graphene)
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73.40.Cg
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(Contact resistance, contact potential)
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73.40.Sx
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(Metal-semiconductor-metal structures)
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