Correlating Raman Spectral Signatures with Carrier Mobility in Epitaxial Graphene: A Guide to Achieving High Mobility on the Wafer Scale

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Robinson, Joshua A.
Wetherington, Maxwell
Tedesco, Joseph L.
Campbell, Paul M.
Weng, Xiaojun
Stitt, Joseph
Fanton, Mark A.
Frantz, Eric
Snyder, David
VanMil, Brenda L.
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Abstract
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We report a direct correlation between carrier mobility and Raman topography of epitaxial graphene (EG) grown on silicon carbide (SiC). We show the Hall mobility of material on the Si-face of SiC [SiC(0001)] is not only highly dependent on thickness uniformity but also on monolayer strain uniformity. Only when both thickness and strain are uniform over a significant fraction (> 40%) of the device active area does the mobility exceed 1000 cm2/V-s. Additionally, we achieve high mobility epitaxial graphene (18,100 cm2/V-s at room temperature) on the C-face of SiC [SiC(000-1)] and show that carrier mobility depends strongly on the graphene layer stacking. These findings provide a means to rapidly estimate carrier mobility and provide a guide to achieve very high mobility in epitaxial graphene. Our results suggest that ultra-high mobilities (>50,000 cm2/V-s) are achievable via the controlled formation of uniform, rotationally faulted epitaxial graphene.
Comment: 13 pages including supplimental material. Submitted to Nature Materials 2/23/2009
Keywords
Condensed Matter - Materials Science
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