Quasi-Freestanding Graphene on SiC(0001)

Speck, Florian; Ostler, Markus; Röhrl, Jonas; Jobst, Johannes; Waldmann, Daniel; Hundhausen, Martin; Ley, Lothar; Weber, Heiko B.; Seyller, Thomas

doi:10.4028/www.scientific.net/MSF.645-648.629

Paper Titles

Deep UV Raman Spectroscopy of Epitaxial Graphenes on Vicinal 6H-SiC Substrates
p.611

Optical Transmission of Epitaxial Graphene Layers on SiC in the Visible Spectral Range
p.615

Density Functional Simulations of Physisorbed and Chemisorbed Single Graphene Layers on 4H-SiC (0001), (000-1) and 4H-SiC:H Surface
p.619

Hydrogen Intercalation below Epitaxial Graphene on SiC(0001)
p.623

Quasi-Freestanding Graphene on SiC(0001)
p.629

Techniques for the Dry Transfer of Epitaxial Graphene onto Arbitrary Substrates
p.633

Transport Properties of Single-Layer Epitaxial Graphene on 6H-SiC (0001)
p.637

Defect Control in Growth and Processing of 4H-SiC for Power Device Applications
p.645

Effects of Thermal Oxidation on Deep Levels Generated by Ion Implantation into n-Type and p-Type 4H-SiC
p.651

HomeMaterials Science ForumSilicon Carbide and Related Materials 2009Quasi-Freestanding Graphene on SiC(0001)

Quasi-Freestanding Graphene on SiC(0001)

Abstract:

We report on a comprehensive study of the properties of quasi-freestanding monolayer and bilayer graphene produced by conversion of the (6√3×6√3)R30° reconstruction into graphene via intercalation of hydrogen. The conversion is confirmed by photoelectron spectroscopy and Raman spectroscopy. By using infrared absorption spectroscopy we show that the underlying SiC(0001) surface is terminated by hydrogen in the form of Si-H bonds. Using Hall effect measurements we have determined the carrier concentration and type as well as the mobility which lies well above 1000 cm2/Vs despite a significant amount of short range scatterers detected by Raman spectroscopy.

Info:

Periodical:

Materials Science Forum (Volumes 645-648)

Main Theme:

Silicon Carbide and Related Materials 2009

Edited by:

Anton J. Bauer, Peter Friedrichs, Michael Krieger, Gerhard Pensl, Roland Rupp and Thomas Seyller

Pages:

629-632

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.645-648.629

Citation:

F. Speck et al., "Quasi-Freestanding Graphene on SiC(0001)", Materials Science Forum, Vols. 645-648, pp. 629-632, 2010

Online since:

April 2010

Authors:

Florian Speck, Markus Ostler, Jonas Röhrl, Johannes Jobst, Daniel Waldmann, Martin Hundhausen, Lothar Ley, Heiko B. Weber, Thomas Seyller

Keywords:

Graphen, Hall Effect, Infrared Absorption, Raman Spectroscopy

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References

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Paper TitlePages

Tailoring the SiC Subsurface Stacking by the Chemical Potential

Authors: Ulrich Starke, J. Bernhardt, J. Schardt, A. Seubert, K. Heinz

415

Impact of Substrate Steps and of Monolayer-Bilayer Junctions on the Electronic Transport in Epitaxial Graphene on 4H-SiC (0001)

Authors: Filippo Giannazzo, Ioannis Deretzis, Antonino La Magna, Salvatore di Franco, Nicolò Piluso, Patrick Fiorenza, Fabrizio Roccaforte, Patrick Schmid, Wilfried Lerch, Rositza Yakimova

Abstract: Two dimensional maps of the electronic conductance in epitaxial graphene (EG) grown on SiC were obtained by conductive atomic force microscopy (CAFM). The correlation between morphological and electrical maps revealed the local conductance degradation in EG over the SiC substrate steps or at the junction between monolayer (1L) and bilayer (2L) graphene regions. The effect of steps strongly depends on the charge transfer phenomena between the step sidewall and graphene, whereas the resistance increase at 1L/2L junction is a purely quantum mechanical effect, due to the weak coupling between 1L and 2L electron wavefunctions.

113

Electrical Characterization of Epitaxial Graphene Field-Effect Transistors with High-k Al₂O₃ Gate Dielectric Fabricated on SiC Substrates

Authors: Toby Hopf, Konstantin Vassilevski, Enrique Escobedo-Cousin, Peter King, Nicholas G. Wright, Anthony G. O’Neill, Alton B. Horsfall, Jonathan Goss, George Wells, Michael Hunt

Abstract: Top-gated field-effect transistors have been created from bilayer epitaxial graphene samples that were grown on SiC substrates by a vacuum sublimation approach. A high-quality dielectric layer of Al₂O₃ was grown by atomic layer deposition to function as the gate oxide, with an e-beam evaporated seed layer utilized to promote uniform growth of Al₂O₃ over the graphene. Electrical characterization has been performed on these devices, and temperature-dependent measurements yielded a rise in the maximum transconductance and a significant shifting of the Dirac point as the operating temperature of the transistors was increased.

937

Influence of Polymer Residues on the Double Resonance Process of Bilayer Graphene

Authors: Xin Gong, Yue Hui Jia, Pei Peng, Zi Dong Wang, Zhong Zheng Tian, Li Ming Ren, Yun Yi Fu

Abstract: PMMA is commonly used for graphene transfer and device processing. However, it leaves a thin layer of polymer residues after standard acetone cleaning and causes electrical and thermal performance degradation of graphene devices. In this paper, we present a research of the impact of polymer residues on surface morphologies and electronic properties of bilayer graphene using Raman spectroscopy in combination with atomic force microscopy (AFM). The electronic structure of bilayer graphene is well captured in its Raman spectrum, of which the 2D band reveals four double resonance Raman scattering processes. The Raman analyses show universal blueshifts of the G band and the four 2D sub-bands P₁₁, P₁₂, P₂₁, P₂₂, as well as reduced intensity ratios of the sub-bands to the G band I(P_ij)/I(G) after surface contamination by polymer residues, implying an electronic structure modulation in bilayer graphene. The effects are mainly attributed to p-type doping and extrinsic scattering induced by residual impurities and defects.

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