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Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC
AbstractGraphene grown on C-face SiC substrates using two procedures, high and low growth temperature and different ambients, was investigated using Low Energy Electron Microscopy (LEEM), X-ray Photo Electron Electron Microscopy (XPEEM), selected area Low Energy Electron Diffraction (μ-LEED) and selected area Photo Electron Spectroscopy (μ-PES). Both types of samples showed formation of μm-sized grains of graphene. The sharp (1 × 1) μ-LEED pattern and six Dirac cones observed in constant energy photoelectron angular distribution patterns from a grain showed that adjacent layers are not rotated relative to each other, but that adjacent grains in general have different azimuthal orientations. Diffraction spots from the SiC substrate appeared in μ-LEED patterns collected at higher energies, showing that the rotation angle between graphene and SiC varied. C 1s spectra collected did not show any hint of a carbon interface layer. A hydrogen treatment applied was found to have a detrimental effect on the graphene quality for both types of samples, since the graphene domain/grain size was drastically reduced. From hydrogen treated samples, μ-LEED showed at first a clear (1 × 1) pattern, but within minutes, a pattern containing strong superstructure spots, indicating the presence of twisted graphene layers. The LEED electron beam was found to induce local desorption of hydrogen. Heating a hydrogenated C-face graphene sample did not restore the quality of the original as-grown sample.
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Johansson, L.I.; Xia, C.; Hassan, J.U.; Iakimov, T.; Zakharov, A.A.; Watcharinyanon, S.; Yakimova, R.; Janzén, E.; Virojanadara, C. Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC. Crystals 2013, 3, 1-13.View more citation formats
Johansson LI, Xia C, Hassan JU, Iakimov T, Zakharov AA, Watcharinyanon S, Yakimova R, Janzén E, Virojanadara C. Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC. Crystals. 2013; 3(1):1-13.Chicago/Turabian Style
Johansson, Leif I.; Xia, Chao; Hassan, Jawad U.; Iakimov, Tihomir; Zakharov, Alexei A.; Watcharinyanon, Somsakul; Yakimova, Rositza; Janzén, Erik; Virojanadara, Chariya. 2013. "Is the Registry Between Adjacent Graphene Layers Grown on C-Face SiC Different Compared to That on Si-Face SiC." Crystals 3, no. 1: 1-13.