Surface Evolution of 4H-SiC(0001) during &lt;i&gt;In Situ &lt;/i&gt;Surface Preparation and its Influence on Graphene Properties

Ul-Hassan, Jawad; Meyer, Axel; Çakmakyapan, Semih; Kazar, Özgür; Flege, Jan Ingo; Falta, J.; Özbay, Ekmel; Janzén, Erik

doi:10.4028/www.scientific.net/msf.740-742.157

Cited by 4 publications

(10 citation statements)

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“…The absence of large steps is mainly due to substrate surface preparation at low temperature and pressure and the subsequent growth under background pressure of Si. Similar reconstruction of 0.5-1 nm steps into 2-4 nm steps has been reported during graphene growth in vacuum on bare substrates that were etched in hydrogen prior to the growth of graphene [30]. However, in this case, large steps are also observed on the surface due to high temperature surface preparation.…”

Section: Growth Of Monolayer and Bilayer Graphene Under Si Ambientmentioning

confidence: 56%

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: Growth Of Monolayer and Bilayer Graphene Under Si Ambientmentioning

confidence: 56%

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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“…The XPS analysis of the pyrolyzed PEGM‐modified SMP‐10 confirms the presence of several C x SiO y components in the Si2p core level spectrum. The C 4 Si‐ and C 3 SiO‐type bonding was observed in the sample pyrolyzed at 600°C whereas on further heat treatment at 1200°C, silicon exists almost exclusively as C 2 SiO 2 ‐type bonding together with component related to silica (SiO 4 bonding) . Furthermore, in the C1s spectrum, an increased chemical shift of the C‐Si component can be observed which indicates that the corresponding carbon atoms form more bonds to silicon, that is, CSi 4 .…”

Section: Resultsmentioning

confidence: 95%

“…In fact, the main C‐C peak in the C1s spectrum indicates the presence of sp 2 ‐hybridized carbon because of its asymmetric shape modeled by a Doniach‐Sunjic line profile and because of the shake‐up visible at slightly higher energies . This suggests the presence of graphene at the surface . Overall, this leads to the conclusion that during pyrolysis, the carbon‐rich C x SiO y oxidizes further, even forming energetically favorable silica, while the carbon partially segregates to the surface to form grapheme …”

Section: Resultsmentioning

confidence: 99%

“…The elemental analysis of the ceramics obtained via pyrolysis of the PEGM-modified SMP-10 at 600°C shows the [20][21][22] Furthermore, in the C1s spectrum, an increased chemical shift of the C-Si component can be observed which indicates that the corresponding carbon atoms form more bonds to silicon, that is, CSi 4 . This does not contradict the decreased C 4 Si component as the silicon can be bond not only to carbon but also to oxygen at the same time.…”

Section: Nomentioning

confidence: 98%

“…The C 4 Si-and C 3 SiO-type bonding was observed in the sample pyrolyzed at 600°C whereas on further heat treatment at 1200°C, silicon exists almost exclusively as C 2 SiO 2 -type bonding together with component related to silica (SiO 4 bonding). [20][21][22] Furthermore, in the C1s spectrum, an increased chemical shift of the C-Si component can be observed which indicates that the corresponding carbon atoms form more bonds to silicon, that is, CSi 4 . This does not contradict the decreased C 4 Si component as the silicon can be bond not only to carbon but also to oxygen at the same time.…”

Section: Nomentioning

confidence: 99%

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High surface area SiC(O)‐based ceramic by pyrolysis of poly (ethylene glycol) methacrylate‐modified polycarbosilane

et al. 2019

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In the present work, a high surface area SiC(O)‐based ceramic powder was synthesized upon thermal transformation of a polymer‐derived macromolecular precursor, which was obtained by the chemical modification of a allylhyldrido polycarbosilane with poly(ethylene glycol) methaacrylate under argon environment. The pyrolysis of developed precursor led to the formation of amorphous and high surface area SiC(O)‐based ceramic powder with in situ generated micro/meso‐porosity. The specific surface area of the obtained powders depends on the processing temperature. It decreases from 363 to 122 m2/g as the pyrolysis temperature increases from 600 to 1200°C, respectively. Furthermore the promising samples were fabricated using pressing technique, which led to crack‐free SiC(O) monoliths on subsquent heat treatment. The present study also emphasizes the potential of produced SiC(O) ceramic powder to support NiO catalyst. The impregnation method were used to produce high surface area NiO@SiC(O) ceramic powder (NiO as a catalyst; SiC(O) as a catalyst support) for further catalytic applications. Interestingly, the distribution of the NiO was shown to strongly depend on the oxygen content present in the SiC(O) matrix. Thus, larger oxygen contents induce homogeneously distributed flower‐like NiO catalyst onto SiC(O).

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Minimum Resistance Anisotropy of Epitaxial Graphene on SiC

Pakdehi

Aprojanz

Susloparova

et al. 2018

ACS Appl. Mater. Interfaces

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We report on electronic transport measurements in rotational square probe configuration in combination with scanning tunneling potentiometry of epitaxial graphene monolayers which were fabricated by polymer-assisted sublimation growth on SiC substrates. The absence of bilayer graphene on the ultralow step edges of below 0.75 nm scrutinized by atomic force microscopy and scanning tunneling microscopy result in a not yet observed resistance isotropy of graphene on 4H- and 6H-SiC(0001) substrates as low as 2%. We combine microscopic electronic properties with nanoscale transport experiments and thereby disentangle the underlying microscopic scattering mechanism to explain the remaining resistance anisotropy. Eventually, this can be entirely attributed to the resistance and the number of substrate steps which induce local scattering. Thereby, our data represent the ultimate limit for resistance isotropy of epitaxial graphene on SiC for the given miscut of the substrate.

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Surface Evolution of 4H-SiC(0001) during <i>In Situ </i>Surface Preparation and its Influence on Graphene Properties

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Cited by 4 publications

References 2 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

High surface area SiC(O)‐based ceramic by pyrolysis of poly (ethylene glycol) methacrylate‐modified polycarbosilane

Minimum Resistance Anisotropy of Epitaxial Graphene on SiC

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