Electrical Homogeneity Mapping of Epitaxial Graphene on Silicon Carbide

Patrick Rebsdorf Whelan, Vishal Panchal, Dirch Hjorth Petersen, David M. A. Mackenzie, Christos Melios, Iwona Pasternak, John Gallop, Frederik Westergaard Østerberg, Peter Uhd Jepsen, Wlodek Strupinski, Olga Kazakova, Peter Bøggild*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Epitaxial graphene is a promising route to wafer scale production of electronic graphene devices. Chemical vapor deposition of graphene on silicon carbide offers epitaxial growth with layer control, but is subject to significant spatial and wafer-to-wafer variability. We use terahertz time-domain spectroscopy and micro four-point probes to analyze the spatial variations of quasi-free-standing bi-layer graphene grown on 4 inch silicon carbide (SiC) wafers, and find significant variations in electrical properties across large regions, which are even reproduced across graphene on different SiC wafers cut from the same ingot. The DC sheet conductivity of epitaxial graphene was found to vary more than one order of magnitude across a 4 inch SiC wafer. To determine the origin of the variations, we compare different optical and scanning probe microscopies with the electrical measurements from nano- to millimeter scale and identify three distinct qualities of graphene, which can be attributed to the microstructure of the SiC surface.
Original languageEnglish
JournalA C S Applied Materials and Interfaces
Issue number37
Pages (from-to)31641-31647
Publication statusPublished - 2018


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