Quantum-Hall plateau-plateau transition in top-gated epitaxial graphene grown on SiC (0001)

Abstract

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 ~7 and an electron mobility up 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^{-κ} with exponent κ~0.42. This universal scaling exponent agrees well with those found in III-V heterojunctions with short range alloy disorders and in exfoliated graphene.

accepted by Journal of Applied Physics

References in corpus (10)

• Electric Field Effect in Atomically Thin Carbon Films
• Room-Temperature Quantum Hall Effect in Graphene
• Substrate-induced band gap opening in epitaxial graphene
• Realization of a High Mobility Dual-gated Graphene Field Effect Transistor with Al2O3 Dielectric
• Epitaxial graphene transistors on SiC substrates
• Top-gated graphene field-effect-transistors formed by decomposition of SiC
• Magnetic oscillations in planar systems with the Dirac-like spectrum of quasiparticle excitations II: transport properties
• Anomalously strong pinning of the filling factor nu=2 in epitaxial graphene
• Morphology Characterization of Argon-Mediated Epitaxial Graphene on C-face SiC
• Experimental Studies of Scaling Behavior of a Quantum Hall System with a Tunable Landau Level Mixing

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• Observation of quantum Hall plateau-plateau transition and scaling behavior of the zeroth Landau level in graphene p-n-p junctions
• Supersymmetry approach to delocalization transitions in a network model of the weak field quantum Hall effect and related models