Determination of non-uniform graphene thickness on SiC (0001) by X-ray diffraction

Ruammaitree, Akkawat; Nakahara, Hiroyuki; Akimoto, Koichi; Soda, Kazuo; Saito, Yahachi

doi:10.1016/j.apsusc.2013.05.122

Cited by 45 publications

(36 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The chemical composition of the 4–6 carbophene samples were further studied by XPS analysis44454647. Figure 7(a) is the fully XPS spectrum of the 2D crystal sample coated on copper foil, which shows peaks corresponding to elements C, Cu, Al, and O.…”

Section: Resultsmentioning

confidence: 99%

A new type of two-dimensional carbon crystal prepared from 1,3,5-trihydroxybenzene

Tang

Huang

et al. 2017

Sci Rep

View full text Add to dashboard Cite

A new two-dimensional (2D) carbon crystal, different from graphene, has been prepared from 1,3,5-trihydroxybenzene, consisting of 4-carbon and 6-carbon rings in 1:1 ratio, named 4-6 carbophene by authors, in which all carbon atoms possess sp 2 hybrid orbitals with some distortion, forming an extensive conjugated π-bonding planar structure. The angles between the three σ-bonds of the carbon sp 2 orbitals are roughly 120°, 90°, and 150°. Each of the three non-adjacent sides of a 6C-ring is shared with a 4C-ring; and each of the two opposite sides of a 4C-ring is shared with a 6C-ring. Dodecagonal holes with a diameter of approximate 5.8 Å are regularly located throughout the 2D carbon crystal. Even though the bond energies in 4-6 carbophene are weaker than those in the graphene, the new planar crystal is quite stable in ambient conditions. The 4-6 carbophene can be synthetized from 1,3,5-trihydroxybenzene or other benzene derivatives through dehydration and polymerization reactions, and may possess several possible patterns that form a family of 2D carbon crystals. A possible side reaction involving 1,3,5-trihydroxybenzene is also discussed, which may produce a carbon-oxygen two dimensional crystal.Graphene 1,2 is an allotrope of elemental carbon in the form of an atomic-scale, two-dimensional, honey-comb lattice, in which all carbon atoms are in sp 2 electron configuration, resulting in an extensive conjugated π -system. Graphene is the basic structural element of several other carbon allotropes, including graphite 3,4 , carbon nanotubes 5 and fullerenes (C 60 ) 6 . Graphene is an excellent material possessing many outstanding physical and chemical properties, such as high electrical and thermal conductivity 7 , huge specific surface area 8 , good optical transparency 2 , and excellent mechanical strength 9,10 . Therefore, graphene is expected to have many applications in broad areas 11,12 .From material science and structural chemistry viewpoints, graphene is a two-dimensional (2D) crystal and a 2D carbon material 13 . Since the first 2D carbon crystal graphene was found in 2004 1,2 , several other 2D crystals and materials of carbon have emerged 14,15 . In recent years the 2D crystals and materials become a booming research field. A comprehensive review on this field can be found in a review article by Peng et al. 16 . Chemically, a sheet of graphene is a large aromatic molecule consisting of hexagonal planar structural units 17,18 that are similar to anthracene and phenanthrene. In graphene, all carbon atoms are in standard sp 2 electronic configuration so that the angles between the three σ -bonds of carbon sp 2 orbitals are 120°, 120°, and 120°, just as they are in the carbon atoms in benzene and other aromatic molecules 19,20 .Actually, the orbitals in carbon atoms can also be in a distorted sp 2 hybrid form, resulting in planar structural units other than hexagons [21][22][23][24] . This possibility raises an interesting question: "Are there other two-dimensional carbon crystals that are different from gra...

show abstract

Section: Resultsmentioning

confidence: 99%

A new type of two-dimensional carbon crystal prepared from 1,3,5-trihydroxybenzene

Tang

Huang

et al. 2017

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Because the graphene ring is obviously higher than the SiC substrate surface, bonds cannot form between the graphene ring edge and the SiC substrate. Previous results revealed that the graphene on the 0.3‐atm 1675 °C sample originates from C diffusion. The average terrace width on this sample is approximately 1.25 µm.…”

Section: Resultsmentioning

confidence: 54%

“…The structure and orientation of graphene and SiC on the samples were measured by reflection high‐energy electron diffraction (RHEED). The results reveal that the graphene unit cell is rotated by 30° with respect to the SiC unit cell (for details, please see our previous study). The edge direction of graphene rings was determined using STM measurements.…”

Section: Resultsmentioning

confidence: 99%

“…An analytical model by Liu et al revealed that the electric field enhancement factor of graphene plasmons from graphene rings is about 20 times that from gold nanorings . Large graphene can be fabricated in many ways, such as mechanical exfoliation of graphite, chemical vapor deposition of carbon‐bearing gases on the surface of copper films, and annealing of SiC substrates . Although a graphene ring can be created by simple top–down methods such as eletron‐beam lithography, these methods generate graphene rings with damaged edges.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Growth of protrusive graphene rings on Si‐terminated 6H–SiC (0001)

Ruammaitree

Nakahara

Saito

2014

Surface & Interface Analysis

Self Cite

View full text Add to dashboard Cite

Optical antennas are devices that efficiently convert the energy of free propagating radiation into localized energy and vice versa. The development of optical antennas can improve the eff iciency of sensing, photodetection, light emission, and spectroscopy. Graphene rings are a promising material for advanced optical antennas because their plasmons are more electromagnetically conf ined than metallic plasmons. In this report, we describe the growth of embedded and protrusive graphene rings by annealing Si-terminated 6H-SiC under Ar gas. We found that the growth of the graphene rings depends on both the annealing temperature and the ambient Ar pressure. A bottom-up fabrication method can preserve intact ring edges unlike electron-beam lithographic methods. Moreover, the growth of protrusive graphene rings without bonding between the ring edge and the SiC substrate is emphasized because the ring edge structures are similar to those of free-standing graphene rings, and this provides a new option for graphene applications on Si-terminated SiC.

show abstract

“…The signal measured by ellipsometry depends on the thickness and the optical constants of the layer and thus, the thickness cannot be directly determined. X-ray diffraction has been also used to determine the thickness distribution of graphene layer [3]; this method needs high energy X-ray facility, however. It is interesting that Auger electron spectroscopy (AES), the classical surface sensitive analytical tool, has been rarely used in graphene research.…”

Section: Introductionmentioning

confidence: 99%

Determination of the thickness distribution of a graphene layer grown on a 2″ SiC wafer by means of Auger electron spectroscopy depth profiling

Kotis

Gurban

Pécz

et al. 2014

Applied Surface Science

View full text Add to dashboard Cite

Auger electron spectroscopy (AES) depth profiling was applied for determination of the thickness of a macroscopic size graphene sheet grown on 2 inch 6H-SiC (0001) by sublimation epitaxy. The measured depth profile deviated from the expected exponential form showing the presence of an additional, buffer layer. The measured depth profile was compared to the simulated one which allowed the derivation of the thicknesses of the graphene and buffer layers and the Si concentration of buffer layer. It has been shown that the C made buffer layer contains about 30% unsaturated Si. The depth profiling was 2 carried out in several points (diameter 50m), which permitted the constructing of a thickness distribution characterizing the uniformity of the graphene sheet.

show abstract

Determination of non-uniform graphene thickness on SiC (0001) by X-ray diffraction

Cited by 45 publications

References 19 publications

A new type of two-dimensional carbon crystal prepared from 1,3,5-trihydroxybenzene

A new type of two-dimensional carbon crystal prepared from 1,3,5-trihydroxybenzene

Growth of protrusive graphene rings on Si‐terminated 6H–SiC (0001)

Determination of the thickness distribution of a graphene layer grown on a 2″ SiC wafer by means of Auger electron spectroscopy depth profiling

Contact Info

Product

Resources

About