Homogeneous Large-Area Quasi-Free-Standing Monolayer and Bilayer Graphene on SiC
| Autor: | Thorsten Dziomba, Davood Momeni Pakdehi, Hans Werner Schumacher, Christoph Tegenkamp, Johannes Aprojanz, Andrey Bakin, Franz J. Ahlers, Rainer Stosch, Frank Hohls, Stefan Wundrack, Thi Thuy Nhung Nguyen, Klaus Pierz |
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| Rok vydání: | 2019 |
| Předmět: |
Condensed Matter - Materials Science
Materials science Condensed Matter - Mesoscale and Nanoscale Physics Graphene Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences law.invention symbols.namesake Electron diffraction Chemical physics law Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Monolayer Homogeneity (physics) symbols General Materials Science Scanning tunneling microscope Raman spectroscopy Bilayer graphene Anisotropy |
| Zdroj: | ACS Applied Nano Materials. 2:844-852 |
| ISSN: | 2574-0970 |
| Popis: | In this study, we first show that the argon flow during epitaxial graphene growth is an important parameter to control the quality of the buffer and the graphene layer. Atomic force microscopy (AFM) and low-energy electron diffraction (LEED) measurements reveal that the decomposition of the SiC substrate strongly depends on the Ar mass flow rate while pressure and temperature are kept constant. Our data are interpreted by a model based on the competition of the SiC decomposition rate, controlled by the Ar flow, with a uniform graphene buffer layer formation under the equilibrium process at the SiC surface. The proper choice of a set of growth parameters allows the growth of defect-free, ultra-smooth and coherent graphene-free buffer layer and bilayer-free monolayer graphene sheets which can be transformed into large-area high-quality quasi-freestanding monolayer and bilayer graphene (QFMLG and QFBLG) by hydrogen intercalation. AFM, scanning tunneling microscopy (STM), Raman spectroscopy and electronic transport measurements underline the excellent homogeneity of the resulting quasi-freestanding layers. Electronic transport measurements in four-point probe configuration reveal a homogeneous low resistance anisotropy on both {\mu}m- and mm scales. Comment: Supplementary data is included |
| Databáze: | OpenAIRE |
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