Imaging the interface of epitaxial graphene with silicon carbide via scanning tunneling microscopy

Rutter, Gregory M.; Guisinger, Nathan P.; Crain, Jason; Jarvis, Emily; Stiles, Mark D.; Li, T; First, Phillip N.; Stroscio, Joseph A.

doi:10.1103/physrevb.76.235416

Cited by 190 publications

(258 citation statements)

References 26 publications

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“…The variation was confirmed by atomic force microscopy (AFM) thus excluding electronic effects which often mimic height variations in STM. The apparent heights of 2.3Å correlate nicely with the graphene step height seen for graphene on buffer-layer on SiC(0001) 12 and shows that the high-and low-contrast seen in SEM is related to the buffer-layer and graphene phases, respectively. Furthermore, as supported by AFM (cf.…”

supporting

confidence: 65%

Local transport measurements on epitaxial graphene

Baringhaus

Edler

Neumann

et al. 2013

Applied Physics Letters

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Growth of large-scale graphene is still accompanied by imperfections. By means of a four-tip STM/SEM the local structure of graphene grown on SiC(0001) was correlated with scanning electron microscope images and spatially resolved transport measurements. The systematic variation of probe spacings and substrate temperature has clearly revealed two-dimensional transport regimes of Anderson localization as well as of diffusive transport. The detailed analysis of the temperature dependent data demonstrates that the local on-top nano-sized contacts do not induce significant strain to the epitaxial graphene films.

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supporting

confidence: 65%

Local transport measurements on epitaxial graphene

Baringhaus

Edler

Neumann

et al. 2013

Applied Physics Letters

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“…However, such pattern is not relevant for the present study since it results from the interface contribution to the image. 46,[63][64][65] Note that this image contains 2048 × 2048 pixels, which is sufficient to resolve the graphene honeycomb atomic structure: Indeed, it shows up (together with the 6 × 6 modulation) in numerical zooms taken at random spots on Fig. 2 (ii) Rings of radius 2q F ≈ 1.1 nm −1 , associated to intervalley scattering, are found centered at K p , K p points, but with suppressed intensity along directions perpendicular to…”

Section: High-resolution Stm Results On Monolayer Graphene On Sicmentioning

confidence: 94%

Role of pseudospin in quasiparticle interferences in epitaxial graphene probed by high-resolution scanning tunneling microscopy

et al. 2012

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Pseudospin, an additional degree of freedom emerging in graphene as a direct consequence of its honeycomb atomic structure, is responsible for many of the exceptional electronic properties found in this material. This paper is devoted to providing a clear understanding of how graphene's pseudospin impacts the quasiparticle interferences of monolayer (ML) and bilayer (BL) graphene measured by low-temperature scanning tunneling microscopy and spectroscopy. We have used this technique to map, with very high energy and space resolution, the spatial modulations of the local density of states of ML and BL graphene epitaxially grown on SiC(0001), in presence of native disorder. We perform a Fourier transform analysis of such modulations including wave vectors up to unit vectors of the reciprocal lattice. Our data demonstrate that the quasiparticle interferences associated to some particular scattering processes are suppressed in ML graphene, but not in BL graphene. Most importantly, interferences with 2q F wave vector associated to intravalley backscattering are not measured in ML graphene, even on the images with highest resolution where the graphene honeycomb pattern is clearly resolved. In order to clarify the role of the pseudospin on the quasiparticle interferences, we use a simple model which nicely captures the main features observed in our data. The model unambiguously shows that graphene's pseudospin is responsible for such suppression of quasiparticle interference features in ML graphene, in particular for those with 2q F wave vector. It also confirms scanning tunneling microscopy as a unique technique to probe the pseudospin in graphene samples in real space with nanometer precision. Finally, we show that such observations are robust with energy and obtain with great accuracy the dispersion of the π bands for both ML and BL graphene in the vicinity of the Fermi level, extracting their main tight-binding parameters.

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“…For this thickness range, the 6Ö3 layer has already formed on the surface, and this structure could be contributing to the conduction. From tunneling spectroscopy, this layer is known to have a narrow band gap of about 300 meV, 22 although at room temperature a nonzero conductivity at the Fermi level is found (likely due to thermal occupation of states across the gap). 23 In any case, with the complete formation of the first graphene layer the conductivity is significantly increased.…”

Section: Electrical Propertiesmentioning

confidence: 99%

Temperature Dependence of Epitaxial Graphene Formation on SiC(0001)

Luxmi

Nie

Fisher

et al. 2008

Journal of Elec Materi

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The formation of epitaxial graphene on SiC(0001) surfaces is studied using atomic force microscopy, Auger electron spectroscopy, electron diffraction, Raman spectroscopy, and electrical measurements. Starting from hydrogenannealed surfaces, graphene formation by vacuum annealing is observed to begin at about 1150°C, with the overall step-terrace arrangement of the surface being preserved but with significant roughness (pit formation) on the terraces. At higher temperatures near 1250°C, the step morphology changes, with the terraces becoming more compact. At 1350°C and above, the surface morphology changes into relatively large flat terraces separated by step bunches. Features believed to arise from grain boundaries in the graphene are resolved on the terraces, as are fainter features attributed to atoms at the buried graphene/SiC interface.

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Imaging the interface of epitaxial graphene with silicon carbide via scanning tunneling microscopy

Cited by 190 publications

References 26 publications

Local transport measurements on epitaxial graphene

Local transport measurements on epitaxial graphene

Role of pseudospin in quasiparticle interferences in epitaxial graphene probed by high-resolution scanning tunneling microscopy

Temperature Dependence of Epitaxial Graphene Formation on SiC(0001)

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