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Realization of continuous Zachariasen carbon monolayer

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Science Advances  10 Feb 2017:
Vol. 3, no. 2, e1601821
DOI: 10.1126/sciadv.1601821
  • Fig. 1 Islands of layered carbon grown on a Ge(100) surface and spectroscopic analysis of our Z-CM.

    (A) A typical scanning electron microscopy (SEM) image of layered carbon islands during the early stages of growth. Each carbon island is divided into two distinct areas: bright and dark. (B) The diameter of the bright carbon layer area depended on the H2 partial pressure, at a constant ratio of the CH4/H2 inlet gases. (C) SEM images of the layered carbon islands under different PH2 conditions at CH4/H2 = 1:100 after the growth times of 5, 5, 10, and 30 min, respectively. (D) Raman spectra of Z-CM and c-Gr at 514.5 nm. a.u., arbitrary units. (E) X-ray photoelectron spectroscopy (XPS) patterns (C s1 peak) obtained from Z-CM and c-Gr. The spectra were fitted to a single Doniach-Sunjic (D-S) model.

  • Fig. 2 High-resolution transmission electron microscopy (HR-TEM) of Z-CM.

    (A) HR-TEM images of the bright area (Z-CM) of Fig. 1A. The inset shows its FFT pattern. (B) Fivefold enlarged image of white box in (A). The inset shows its FFT pattern. (C) FFT spectrum of the inset of (A) and Gaussian distribution of ring pattern obtained by fitting the spectrum.

  • Fig. 3 Thickness measurements obtained from the Z-CM and c-Gr monolayers.

    (A) An optical image of the vertically stacked Z-CM and c-Gr structure for AFM measurement. (B) Tapping mode AFM image of the boundary between the Z-CM and the c-Gr/Z-CM bilayer. The inset displays an EFM image of (B), in which the monolayer layer is darker than the bilayer. (C) The thickness of the c-Gr layer was measured to be 3.5 Å within the white-boxed area of (B). (D) The thickness of Z-CM was measured to be 4.3 Å. The inset shows an EFM image of (D). (E) Cross-sectional TEM image of the as-grown Z-CM. (F) Raman map (60 × 70 μm2) of the G band intensity of Z-CM.

  • Fig. 4 The electronic properties of Z-CM.

    (A) Sheet resistance curves obtained from Z-CM and c-Gr FETs as a function of the gate bias, measured under high-vacuum conditions (1 × 10–6 torr). The inset shows the results measured from a graphene FET prepared with a Hall bar structure. (B) Low-temperature dependence of the sheet resistance, based on four-probe measurements collected from Z-CM. The red line shows the fitting results to Mott’s 2D VRH model Embedded Image. (C) The large negative MR behavior of Z-CM at low temperatures below 100 K. Rsxx is a longitudinal sheet resistance.

  • Fig. 5 Dielectric layer (Al2O3) deposited on Z-CM and ultrathin silicon layer fabrication using Z-CM.

    (A) SEM image of Al2O3 deposited onto c-Gr via ALD. The inset shows an SEM image of Al2O3 uniformly deposited onto Z-CM using the same method. (B) AFM image of Al2O3 deposited on Z-CM where surface roughness was 2.17 Å root mean square (RMS). (C) Cross-sectional TEM image of (B). (D) C-V characteristics measured at 100 kHz from Al2O3/Z-CM/Ge and Al2O3/Ge capacitors. The C-V curves were normalized with respect to their maximum accumulation capacitances. (E) Patterning and transferring of ultrathin amorphous silicon layer deposited on Z-CM/Ge.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/2/e1601821/DC1

    Supplementary Materials and Methods

    note S1. Raman analysis.

    note S2. XPS analysis.

    table S1. Lattice mismatch of typical catalytic substrates for graphene growth.

    table S2. Fitting parameters from the D-S model.

    table S3. Summary of previous studies on ultrathin dielectric layer deposition on graphene.

    fig. S1. Diameter determination of bright area within islands of layered carbon grown on Ge(100) surface.

    fig. S2. SEM images of islands of layered carbon grown on Ge(100) surface under different total pressure conditions in reaction chamber.

    fig. S3. SEM images of islands of layered carbon grown on Ge(100) surface under different hydrogen pressure conditions in reaction chamber.

    fig. S4. SEM images of islands of layered carbon grown on Ge(100) surface under different hydrogen pressure conditions in reaction chamber.

    fig. S5. HR-TEM image of layered carbon with dark brightness shown in Fig. 1A.

    fig. S6. XPS C 1s spectrum for thermodynamic stability of Z-CM.

    fig. S7. HR-TEM analysis of Z-CM.

    fig. S8. HR-TEM image (#1) and its local FT patterns.

    fig. S9. HR-TEM image (#2) and its local FT patterns.

    fig. S10. HR-TEM image (#3) and its local FT patterns.

    fig. S11. HR-TEM image (#4) and its local FT patterns.

    fig. S12. Thickness measurement of crystalline graphene (c-Gr).

    fig. S13. Thickness measurement of Z-CM.

    fig. S14. Sheet resistance curves obtained from Z-CM, c-Gr, and mixed Gr FETs as a function of gate bias, measured in air with no thermal treatment.

    fig. S15. Negative MR behavior of Z-CM at 2 K.

    fig. S16. Fabrication of ultrathin silicon using Z-CM interlayer.

    fig. S17. Time-of-flight secondary ion mass spectrometry profile of B- (or P-) doped silicon layers deposited on Z-CM layer using LPCVD.

    fig. S18. O 1s XPS spectrum of as-grown Z-CM on Ge.

    References (4351)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Materials and Methods
    • note S1. Raman analysis.
    • note S2. XPS analysis.
    • table S1. Lattice mismatch of typical catalytic substrates for graphene growth.
    • table S2. Fitting parameters from the D-S model.
    • table S3. Summary of previous studies on ultrathin dielectric layer deposition on graphene.
    • fig. S1. Diameter determination of bright area within islands of layered carbon grown on Ge(100) surface.
    • fig. S2. SEM images of islands of layered carbon layered carbon layered carbon layered carbon layered carbon layered carbon layered carbon layered carbon grown on Ge(100) surface under different total pressure conditions in reaction chamber.
    • fig. S3. SEM images of islands of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon grown on Ge(100) surface under different hydrogen pressure conditions in reaction chamber.
    • fig. S4. SEM images of islands of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon of layered carbon grown on Ge(100) surface under different hydrogen pressure conditions in reaction chamber.
    • fig. S5. HR-TEM image of layered carbon with dark brightness shown in Fig. 1A.
    • fig. S6. XPS C 1s spectrum for thermodynamic stability of Z-CM.
    • fig. S7. HR-TEM analysis of Z-CM.
    • fig. S8. HR-TEM image (#1) and its local FT patterns.
    • fig. S9. HR-TEM image (#2) and its local FT patterns.
    • fig. S10. HR-TEM image (#3) and its local FT patterns.
    • fig. S11. HR-TEM image (#4) and its local FT patterns.
    • fig. S12. Thickness measurement of crystalline graphene (c-Gr).
    • fig. S13. Thickness measurement of Z-CM.
    • fig. S14. Sheet resistance curves obtained from Z-CM, c-Gr, and mixed Gr FETs as a function of gate bias, measured in air with no thermal treatment.
    • fig. S15. Negative MR behavior of Z-CM at 2 K.
    • fig. S16. Fabrication of ultrathin silicon using Z-CM interlayer.
    • fig. S17. Time-of-flight secondary ion mass spectrometry profile of B- (or P-) doped silicon layers deposited on Z-CM layer using LPCVD.
    • fig. S18. O 1s XPS spectrum of as-grown Z-CM on Ge.
    • References (43–51)

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