Conductance Anisotropy in Epitaxial Graphene Sheets Generated by Substrate Interactions

Yakes, Michael K.; Gunlycke, Daniel; Tedesco, Joseph L.; Campbell, Paul M.; Myers-Ward, Rachael L.; Eddy, Charles R.; Gaskill, D. Kurt; Sheehan, Paul E.; Laracuente, A. R.

doi:10.1021/nl9035302

Cited by 108 publications

(104 citation statements)

References 34 publications

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“…This suggests that transport properties in graphene bilayers grown on epitaxial SiC inherit the non-uniformity observed in AFM and Raman measurements of graphene bilayers. Furthermore, the bilayer sample exhibits regions of high mobility (>2000 cm 2 /Vs) and low carrier density (<0.9x10 13 investigations showing a correlation between macroscopic electrical measurements and surface morphology [38][39][40]. If these properties could be uniformly achieved over large areas, then bilayers grown on epitaxial SiC layers could offer a substantial improvement to the current technique of graphene grown directly on SI SiC substrates in the context of a device oriented application.…”

Section: Discussionmentioning

confidence: 98%

Quasi-free-standing monolayer and bilayer graphene growth on homoepitaxial on-axis 4H-SiC(0 0 0 1) layers

Hassan

Winters

Ivanov

et al. 2015

Carbon

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Quasi-free-standing monolayer and bilayer graphene growth on homoepitaxial on-axis 4H-SiC (0001) The doping of the SiC epilayers may be modified allowing for graphene to be grown on a conducing substrate. Graphene growth was performed via thermal decomposition of the surface of the SiC epilayers under Si background pressure in order to achieve control on thickness uniformity over large area. Monolayer and bilayer samples were prepared through the conversion of a carbon buffer layer and monolayer graphene respectively using hydrogen intercalation process. Micro-Raman and reflectance mappings confirmed predominantly quasi-free-standing monolayer and bilayer graphene on samples grown under optimized growth conditions.Measurements of the Hall properties of Van der Pauw structures fabricated on these layers show high charge carrier mobility (>2000 cm 2 /Vs) and low carrier density (<0.9x10 13 cm -2 ) in quasifree-standing bilayer samples relative to monolayer samples. Also, bilayers on homoepitaxial layers are found to be superior in quality compared to bilayers grown directly on SI substrates.

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Section: Discussionmentioning

confidence: 98%

Quasi-free-standing monolayer and bilayer graphene growth on homoepitaxial on-axis 4H-SiC(0 0 0 1) layers

Hassan

Winters

Ivanov

et al. 2015

Carbon

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“…Yet, the overestimated step edge resistance of the winding terraces may suggest that graphene's resistance is further augmented by local morphology. Such contribution could be a consequence of residual Si atoms aggregated in the step edge area 55 or growth disorder near the step edges leading to deterioration of graphene's quality and promoting short-range scattering. 72 …”

Section: -5mentioning

confidence: 99%

“…In Ref. 55 (2014) suggested that the conduction anisotropy is a reflection of both geometric anisotropy and the extent of residual silicon atoms aggregated at the step edges, where they enhance carrier scattering.…”

Section: Introductionmentioning

confidence: 99%

Step-edge-induced resistance anisotropy in quasi-free-standing bilayer chemical vapor deposition graphene on SiC

Ciuk

Çakmakyapan

Özbay

et al. 2014

Journal of Applied Physics

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The transport properties of quasi-free-standing (QFS) bilayer graphene on SiC depend on a range of scattering mechanisms. Most of them are isotropic in nature. However, the SiC substrate morphology marked by a distinctive pattern of the terraces gives rise to an anisotropy in graphene's sheet resistance, which may be considered an additional scattering mechanism. At a technological level, the growth-preceding in situ etching of the SiC surface promotes step bunching which results in macro steps ∼ 10? nm in height. In this report, we study the qualitative and quantitative effects of SiC steps edges on the resistance of epitaxial graphene grown by chemical vapor deposition. We experimentally determine the value of step edge resistivity in hydrogen-intercalated QFS-bilayer graphene to be ∼ 190? Ωμ m for step height hS? =? 10? nm and provide proof that it cannot originate from mechanical deformation of graphene but is likely to arise from lowered carrier concentration in the step area. Our results are confronted with the previously reported values of the step edge resistivity in monolayer graphene over SiC atomic steps. In our analysis, we focus on large-scale, statistical properties to foster the scalable technology of industrial graphene for electronics and sensor applications. © 2014 AIP Publishing LLC

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“…It was found that the graphene sheet resistance was highly dependent upon the orientation of the TFM pattern. Conductance anisotropy in graphene sheets on semi-insulating SiC has been studied using scanning tunneling microscopy, and this observation is a verification of this effect on a much larger scale [8]. The average contact resistance was 1.50-mm, independent of orientation.…”

Section: Characterization and Analysismentioning

confidence: 83%

Investigation of the Epitaxial Graphene/p-SiC Heterojunction

Anderson

Hobart

Nyakiti

et al. 2012

IEEE Electron Device Lett.

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Abstract-There has been significant research in the study of in-plane charge-carrier transport in graphene in order to understand and exploit its unique electrical properties; however, the vertical graphene-semiconductor system also presents opportunities for unique devices. In this letter, we investigate the epitaxial graphene/p-type 4H-SÍC system to better understand this vertical heterojunction. The I-V behavior does not demonstrate thermionic emission properties that are indicative of a Schottky barrier but rather demonstrates characteristics of a semiconductor heterojunction. This is confirmed by the fitting of the temperature-dependent I-V curves to classical heterojunction equations and the observation of band-edge electroluminescence in SiC.

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Conductance Anisotropy in Epitaxial Graphene Sheets Generated by Substrate Interactions

Cited by 108 publications

References 34 publications

Quasi-free-standing monolayer and bilayer graphene growth on homoepitaxial on-axis 4H-SiC(0 0 0 1) layers

Quasi-free-standing monolayer and bilayer graphene growth on homoepitaxial on-axis 4H-SiC(0 0 0 1) layers

Step-edge-induced resistance anisotropy in quasi-free-standing bilayer chemical vapor deposition graphene on SiC

Investigation of the Epitaxial Graphene/p-SiC Heterojunction

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