We investigate the low-temperature magneto-transport properties of monolayer epitaxial graphene films formed on the Si-face of semi-insulating 4H SiC substrates by a high-temperature sublimation process. A high-k top-gate on the epitaxial graphene is realized by inserting a fully oxidized nanometer-thin aluminum film as a seeding layer, followed by an atomic layer deposition process. At low temperatures, the devices demonstrate a strong field effect by the top gate with an on/off ratio of similar to 7 and an electron mobility up to similar to 3250 cm(2)/Vs. After the observation of the half-integer quantum-Hall effect for monolayer epitaxial graphene films, detailed magneto-transport measurements have been carried out including varying densities, temperatures, magnetic fields, and currents. We study the width of the distinguishable quantum-Hall plateau to plateau transition (Landau level index n=0 to n=1) as temperature (T) and current are varied. For both gate voltage and magnetic field sweeps and T>10 K, the transition width goes as T-kappa with exponent k similar to 0.42. This universal scaling exponent agrees well with those found in III V heterojunctions with short-range alloy disorders and in exfoliated graphene. VC 2012 American Institute of Physics. [doi:10.1063/1.3675464]
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Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 111, 013716 (2012) and may be found at http://dx.doi.org/10.1063/1.3675464. The following article has been submitted to/accepted by Journal of Applied Physics. Copyright 2012 T. Shen, A. T. Neal, M. L. Bolen, J. J. Gu, L. W. Engel, M. A. Capano and P. D. Ye. This article is distributed under a Creative Commons Attribution 3.0 Unported License.