Comparison of Epitaxial Graphene on Si-face and C-face 4H SiC Formed by Ultrahigh Vacuum and RF Furnace Production

Jernigan, Glenn G.; VanMil, Brenda L.; Tedesco, Joseph L.; Tischler, Joseph G.; Glaser, E. R.; Davidson, Anthony; Campbell, Paul M.; Gaskill, D. Kurt

doi:10.1021/nl900803z

Cited by 145 publications

(124 citation statements)

References 25 publications

(43 reference statements)

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“…This screening preserves the high intrinsic carrier mobility of graphene, allowing for the highest carrier mobility among the three conduction channels. While high carrier mobilities in the quasi-intrinsic part of the MLG have also been previously investigated by far infrared optical absorption techniques [11,12], the results and analysis shown here present the first evidence of such high mobility carriers in electrical measurements. The origin of the dominant hole carriers (p-type doping) in the uppermost graphene layers is currently unknown, but is likely caused by the adsorbed species on the graphene surface.…”

mentioning

confidence: 52%

“…In the Cface MLG, it was noted that cyclotron resonance measurements typically yield much higher carrier mobilities than those obtained from direct electrical measurements [11,12], suggesting non-homogeneous carriers in the system. Therefore, to characterize the transport properties of MLG grown on the C-face of SiC, alternative measurements and analysis techniques are required.…”

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confidence: 99%

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Multicarrier transport in epitaxial multilayer graphene

Lin¹,

Dimitrakopoulos²,

Farmer³

et al. 2010

Applied Physics Letters

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Variable-field Hall measurements were performed on epitaxial graphene grown on Siface and C-face SiC. The carrier transport involves essentially a single-type of carrier in few-layer graphene, regardless of SiC face. However, in multi-layer graphene (MLG) grown on C-face SiC, the Hall measurements indicated the existence of several groups of carriers with distinct mobilities. Electrical transport in MLG can be properly described by invoking three independent conduction channels in parallel. Two of these are n-and p-type, while the third involves nearly intrinsic graphene. The carriers in this lightly doped channel have significantly higher mobilities than the other two.

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confidence: 52%

mentioning

confidence: 99%

Multicarrier transport in epitaxial multilayer graphene

Lin¹,

Dimitrakopoulos²,

Farmer³

et al. 2010

Applied Physics Letters

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“…Those results are in agreement with prior reports of other workers. [1][2][3][4][5][6][7][9][10][11][12][13][14] Before graphene forms on the Si-face, the well known 6√3 layer forms on the surface after annealing in vacuum at temperatures of ≈1200°C. 40 Further heating to about 1250°C produces graphene thickness of 1 -2 ML (Fig.…”

Section: Discussionmentioning

confidence: 99%

Comparison of graphene formation on C-face and Si-face SiC {0001} surfaces

et al. 2010

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The morphology of graphene formed on the ( 1 000 ) surface (the C-face) and the (0001) surface (the Si-face) of SiC, by annealing in ultra-high vacuum or in an argon environment, is studied by atomic force microscopy (AFM) and low-energy electron microscopy (LEEM). The graphene forms due to preferential sublimation of Si from the surface. In vacuum, this sublimation occurs much more rapidly for the C-face than the Si-face, so that 150°C lower annealing temperatures are required for the C-face to obtain films of comparable thickness. The evolution of the morphology as a function of graphene thickness is examined, revealing significant differences between the C-face and the Si-face. For annealing near 1320°C, graphene films of about 2 monolayers (ML) thickness are formed on the Si-face, but 16 ML is found for the C-face. In both cases, step bunches are formed on the surface and the films grow continuously (carpet-like) over the step bunches. For the Si-face in particular, layer-by-layer growth of the graphene is observed in areas between the step bunches. At 1170°C, for the C-face, a more 3-dimensional type of growth is found. The average thickness is then about 4 ML, but with a wide variation in local thickness (2 -7 ML) over the surface. The spatial arrangement of constant-thickness domains are found to be correlated with step bunches on the surface, which form in a more restricted manner than at 1320°C. It is argued that these domains are somewhat disconnected, so that no strong driving force for planarization of the film exists. In a 1-atm argon environment, permitting higher growth temperatures, the graphene morphology for the Si-face is found to become more layer-by-layer-like even for graphene thickness as low as 1 ML. However, for the C-face the morphology becomes much worse, with the surface displaying markedly inhomogeneous nucleation of the graphene. It is demonstrated that these surfaces are unintentionally oxidized, which accounts for the inhomogeneous growth.

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“…Graphene can be also grown epitaxially on SiC surfaces by high temperature Si sublimation, in ultrahigh vacuum (UHV) [8,9] and in controlled environment [10][11][12][13]. Epitaxial graphene can also be grown on the surfaces of various metals such as Pt [14], Ni [15,16], Ir [17,18], Ru [19][20][21], and Cu [22].…”

Section: Graphene Atomic Structurementioning

confidence: 99%

Probing mechanical properties of graphene with Raman spectroscopy

2010

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The use of Raman scattering techniques to study the mechanical properties of graphene films is reviewed here. The determination of Grüneisen parameters of suspended graphene sheets under uni-and bi-axial strain is discussed, and the values are compared to theoretical predictions. The effects of the graphene-substrate interaction on strain and to the temperature evolution of the graphene Raman spectra are discussed. Finally, the relation between mechanical and thermal properties is presented along with the characterization of thermal properties of graphene with Raman spectroscopy.

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Comparison of Epitaxial Graphene on Si-face and C-face 4H SiC Formed by Ultrahigh Vacuum and RF Furnace Production

Cited by 145 publications

References 25 publications

Multicarrier transport in epitaxial multilayer graphene

Multicarrier transport in epitaxial multilayer graphene

Comparison of graphene formation on C-face and Si-face SiC {0001} surfaces

Probing mechanical properties of graphene with Raman spectroscopy

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