Epitaxial graphene homogeneity and quantum Hall effect in millimeter-scale devices

• Published in: Carbon (New York) Vol. 115; pp. 229 - 236
• Main Authors: Yang, Yanfei, Cheng, Guangjun, Mende, Patrick, Calizo, Irene G., Feenstra, Randall M., Chuang, Chiashain, Liu, Chieh-Wen, Liu, Chieh-I., Jones, George R., Hight Walker, Angela R., Elmquist, Randolph E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.05.2017; Elsevier BV
• Subjects: Adsorption; Adsorption-induced molecular doping; Atomic force microscopy; Atomic structure; Carrier density; Critical current (superconductivity); Devices; Doping; Epitaxial graphene; Epitaxial growth; Graphene; Graphite; Hall effect; Homogeneity; Low-energy electron microscopy; Molecular structure; Quantized Hall effect; Quantum Hall effect; Raman microscopy; Silicon carbide; Strain; Sublimation; Topography; Transport mobility; Low-energy electron microscopy; Epitaxial graphene; Transport mobility; Raman microscopy; Quantized Hall effect; Adsorption-induced molecular doping; Carrier density; Strain
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2016.12.087

Quantized magnetotransport is observed in 5.6 × 5.6 mm2 epitaxial graphene devices, grown using highly constrained sublimation on the Si-face of SiC(0001) at high temperature (1900 °C). The precise quantized Hall resistance of Rxy=h2e2 is maintained up to record level of critical current Ixx = 0.72 mA at T = 3.1 K and 9 T in a device where Raman microscopy reveals low and homogeneous strain. Adsorption-induced molecular doping in a second device reduced the carrier concentration close to the Dirac point (n ≈ 1010 cm−2), where mobility of 18760 cm2/V is measured over an area of 10 mm2. Atomic force, confocal optical, and Raman microscopies are used to characterize the large-scale devices, and reveal improved SiC terrace topography and the structure of the graphene layer. Our results show that the structural uniformity of epitaxial graphene produced by face-to-graphite processing contributes to millimeter-scale transport homogeneity, and will prove useful for scientific and commercial applications. [Display omitted]