Atomically Thin Heterostructures Based on Monolayer WSe2 and Graphene

  • Yu-Chuan Lin
Part of the Springer Theses book series (Springer Theses)


Heterogeneous engineering of two-dimensional layered materials, including metallic graphene and semiconducting transition metal dichalcogenides, presents an exciting opportunity to produce highly tunable electronic and optoelectronic systems. In order to engineer pristine layers and their interfaces, epitaxial growth of such heterostructures is desirable. We report the direct growth of crystalline and monolayer tungsten diselenide (WSe2) on epitaxial graphene (EG) on silicon carbide. Raman spectroscopy, photoluminescence, and scanning tunneling microscopy confirm high-quality WSe2 monolayers, while transmission electron microscopy shows an atomically sharp interface, and low-energy electron diffraction confirms near-perfect orientation between WSe2 and EG. Vertical transport measurements across the WSe2/EG heterostructure provide evidence that an additional barrier to carrier transport beyond the expected WSe2/EG band offset exists due to the interlayer gap, which is supported by theoretical local density of states (LDOS) calculations using self-consistent density functional theory (DFT) and non-equilibrium Green’s function (NEGF).


  1. 1.
    Geim, A.K., Grigorieva, I.V.: Van der Waals heterostructures. Nature. 499, 419–425 (2013)CrossRefGoogle Scholar
  2. 2.
    Britnell, L., et al.: Field-effect tunneling transistor based on vertical graphene heterostructures. Science. 335, 947–950 (2012)ADSCrossRefGoogle Scholar
  3. 3.
    Haigh, S.J., et al.: Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices. Nat. Mater. 11, 764–767 (2012)ADSCrossRefGoogle Scholar
  4. 4.
    Lin, Y.-C., et al.: Direct synthesis of van der Waals solids. ACS Nano. 8, 3715–3723 (2014)CrossRefGoogle Scholar
  5. 5.
    Liu, Z., et al.: Direct growth of graphene/hexagonal boron nitride stacked layers. Nano Lett. 11, 2032–2037 (2011)ADSCrossRefGoogle Scholar
  6. 6.
    Shi, Y., et al.: Van der Waals epitaxy of MoS2 layers using graphene as growth templates. Nano Lett. 12, 2784–2791 (2012)ADSCrossRefGoogle Scholar
  7. 7.
    Levendorf, M.P., et al.: Graphene and boron nitride lateral heterostructures for atomically thin circuitry. Nature. 488, 627–632 (2012)ADSCrossRefGoogle Scholar
  8. 8.
    Ohta, T., et al.: Evidence for interlayer coupling and Moiré periodic potentials in twisted bilayer graphene. Phys. Rev. Lett. 109, 186807 (2012)ADSCrossRefGoogle Scholar
  9. 9.
    Robinson, J.T., et al.: Electronic hybridization of large-area stacked graphene films. ACS Nano. 7, 637–644 (2013)CrossRefGoogle Scholar
  10. 10.
    Wallace, R.M.: In-situ characterization of 2D materials for beyond CMOS applications. ECS Trans. 64, 109–116 (2014)CrossRefGoogle Scholar
  11. 11.
    Herrera-Gómez, A., Hegedus, A., Meissner, P.L.: Chemical depth profile of ultrathin nitrided SiO2 films. Appl. Phys. Lett. 81, 1014 (2002)ADSCrossRefGoogle Scholar
  12. 12.
    Lin, Y.-C., et al.: Atomically thin heterostructures based on single-layer tungsten diselenide and graphene. Nano Lett. 14, 6936–6941 (2014)ADSCrossRefGoogle Scholar
  13. 13.
    Robinson, J.A., et al.: Contacting graphene. Appl. Phys. Lett. 98, 053103 (2011)ADSCrossRefGoogle Scholar
  14. 14.
    Das, S., Appenzeller, J.: Where does the current flow in two-dimensional layered systems? Nano Lett. 13, 3396–3402 (2013)ADSCrossRefGoogle Scholar
  15. 15.
    Fang, H., et al.: High-performance single layered WSe2 p-FETs with chemically doped contacts. Nano Lett. 12, 3788–3792 (2012)ADSCrossRefGoogle Scholar
  16. 16.
    de Heer, W.A., et al.: Epitaxial graphene. Solid State Commun. 143, 92–100 (2007)ADSCrossRefGoogle Scholar
  17. 17.
    Robinson, J., et al.: Nucleation of epitaxial graphene on SiC(0001). ACS Nano. 4, 153–158 (2010)CrossRefGoogle Scholar
  18. 18.
    Yeh, P.-C., et al.: Probing substrate-dependent long-range surface structure of single-layer and multilayer MoS2 by low-energy electron microscopy and microprobe. Phys. Rev. B. 89, 155408 (2014)Google Scholar
  19. 19.
    Zhang, Y., et al.: Direct observation of the transition from indirect to direct bandgap in atomically thin epitaxial MoSe2. Nat. Nanotechnol. 9, 111–115 (2014)ADSCrossRefGoogle Scholar
  20. 20.
    Ohta, T., Beechem, T.E., Robinson, J.T., Kellogg, G.L.: Long-range atomic ordering and variable interlayer interactions in two overlapping graphene lattices with stacking misorientations. Phys. Rev. B. 85, 075415 (2012)ADSCrossRefGoogle Scholar
  21. 21.
    Wilson, J.A., Yoffe, A.D.: The transition metal dichalcogenides discussion and interpretation of the observed optical, electrical and structural properties. Adv. Phys. 18, 193–335 (1969)ADSCrossRefGoogle Scholar
  22. 22.
    Koma, A.: Van der Waals epitaxy—a new epitaxial growth method for a highly lattice-mismatched system. Thin Solid Films. 216, 72–76 (1992)ADSCrossRefGoogle Scholar
  23. 23.
    Ji, Q., et al.: Epitaxial monolayer MoS2 on mica with novel photoluminescence. Nano Lett. 13, 3870–3877 (2013)ADSCrossRefGoogle Scholar
  24. 24.
    Hibino, H., et al.: Microscopic thickness determination of thin graphite films formed on SiC from quantized oscillation in reflectivity of low-energy electrons. Phys. Rev. B. 77, 075413 (2008)ADSCrossRefGoogle Scholar
  25. 25.
    Riedl, C., Coletti, C., Iwasaki, T., Zakharov, A.A., Starke, U.: Quasi-free-standing epitaxial graphene on SiC obtained by hydrogen intercalation. Phys. Rev. Lett. 103, 246804 (2009)ADSCrossRefGoogle Scholar
  26. 26.
    Zhang, C., Johnson, A., Hsu, C.-L., Li, L.-J., Shih, C.-K.: Direct imaging of band profile in single layer MoS2 on graphite: quasiparticle energy gap, metallic edge states, and edge band bending. Nano Lett. 14, 2443–2447 (2014)ADSCrossRefGoogle Scholar
  27. 27.
    Weng, X., et al.: Structure of few-layer epitaxial graphene on 6H-SiC(0001) at atomic resolution. Appl. Phys. Lett. 97, 201905 (2010)ADSCrossRefGoogle Scholar
  28. 28.
    McDonnell, S., et al.: Hole contacts on transition metal Dichalcogenides: Interface chemistry and band alignments. ACS Nano. 8, 6265–6272 (2014)CrossRefGoogle Scholar
  29. 29.
    Huang, J.-K., et al.: Large-area synthesis of highly crystalline WSe2 monolayers and device applications. ACS Nano. 8, 923–930 (2014)CrossRefGoogle Scholar
  30. 30.
    Zhang, W., et al.: Ultrahigh-gain photodetectors based on atomically thin graphene-MoS2 heterostructures. Sci. Rep. 4, 3826 (2014)Google Scholar
  31. 31.
    Shim, G.W., et al.: Large area single layer MoSe2 and its van der Waals Heterostructures. ACS Nano. 8, 6655–6662 (2014)CrossRefGoogle Scholar
  32. 32.
    Mouri, S., Miyauchi, Y., Matsuda, K.: Tunable photoluminescence of monolayer MoS2 via chemical doping. Nano Lett. 13, 5944–5948 (2013)ADSCrossRefGoogle Scholar
  33. 33.
    Buscema, M., Steele, G.A., van der Zant, H.S.J., Castellanos-Gomez, A.: The effect of the substrate on the Raman and photoluminescence emission of single-layer MoS2. Nano Res. 7, 561–571 (2014)CrossRefGoogle Scholar
  34. 34.
    Coy Diaz, H., Addou, R., Batzill, M.: Interface properties of CVD grown graphene transferred onto MoS(0001). Nanoscale. 6, 1071–1078 (2014)ADSCrossRefGoogle Scholar
  35. 35.
    Das, S., Appenzeller, J.: WSe2 field effect transistors with enhanced ambipolar characteristics. Appl. Phys. Lett. 103, 103501 (2013)ADSCrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  • Yu-Chuan Lin
    • 1
  1. 1.Center for Nanophase Materials SciencesOak Ridge National LaboratoryOak RidgeUSA

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