Tuning Electronic Transport in WSe2-Graphene

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


In many atomically thin photovoltaic devices, field effect transistors, and tunneling diodes, 2D TMDC have been used as a semiconducting layer in tandem with graphene and many other substrates. It is necessary to achieve efficient charge transport across WSe2-graphene, which creates a semiconductor to semimetal junction. In such cases, the band alignment engineering is required to ensure a low-resistance, ohmic contact. In previous chapter, we cover preparation and fundamental properties of WSe2-graphene. In this chapter, we investigate the impact of graphene properties on the transport at the interface of WSe2-graphene. Electrical transport measurements reveal a change in resistance between WSe2 and fully hydrogenated epitaxial graphene (EGFH) compared to WSe2 grown on partially hydrogenated epitaxial graphene (EGPH). Using low-energy electron microscopy and reflectivity (LEEM/LEER) on these samples, we extract the work function difference between the WSe2 and graphene and employ a charge transfer model to determine the WSe2 carrier density in both cases. The results here indicate that WSe2-EGFH displays nearly ohmic behavior at small biases due to a large hole density in the WSe2, whereas WSe2-EGPH forms a Schottky barrier junction.


  1. 1.
    Lin, Y.-C., et al.: Atomically thin heterostructures based on single-layer tungsten diselenide and graphene. Nano Lett. 14, 6936–6941 (2014)ADSCrossRefGoogle Scholar
  2. 2.
    Eichfeld, S.M., et al.: Highly scalable, atomically thin WSe2 grown via metal-organic chemical vapor deposition. ACS Nano. 9, 2080–2087 (2015)CrossRefGoogle Scholar
  3. 3.
    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
  4. 4.
    Emtsev, K.V., et al.: Towards wafer-size graphene layers by atmospheric pressure graphitization of silicon carbide. Nat. Mater. 8, 203–207 (2009)ADSCrossRefGoogle Scholar
  5. 5.
    Robinson, J.A., et al.: Epitaxial graphene transistors: enhancing performance via hydrogen intercalation. Nano Lett. 11, 3875–3880 (2011)ADSCrossRefGoogle Scholar
  6. 6.
    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
  7. 7.
    Terrones, H., et al.: New first order Raman-active modes in few layered transition metal dichalcogenides. Sci. Rep. 4, 4215 (2014)CrossRefGoogle Scholar
  8. 8.
    Lin, Y.-C., et al.: Tuning electronic transport in epitaxial graphene-based van der Waals heterostructures. Nanoscale. 8, 8947–8954 (2016)ADSCrossRefGoogle Scholar
  9. 9.
    Ferrari, A.C.: Raman spectroscopy of graphene and graphite: disorder, electron–phonon coupling, doping and nonadiabatic effects. Solid State Commun. 143, 47–57 (2007)ADSCrossRefGoogle Scholar
  10. 10.
    Robinson, J.A., Puls, C.P., Staley, N.E., Stitt, J.P., Fanton, M.A.: Raman topography and strain uniformity of large-area epitaxial graphene. Nano Lett. 9, 964–968 (2009)ADSCrossRefGoogle Scholar
  11. 11.
    Das, A., et al.: Monitoring dopants by Raman scattering in an electrochemically top-gated graphene transistor. Nat. Nanotechnol. 3, 210–215 (2008)CrossRefGoogle Scholar
  12. 12.
    Ristein, J., Mammadov, S., Seyller, T.: Origin of doping in quasi-free-standing graphene on silicon carbide. Phys. Rev. Lett. 108, 246104 (2012)ADSCrossRefGoogle Scholar
  13. 13.
    Feenstra, R.M., et al.: Low-energy electron reflectivity from graphene. Phys. Rev. B. 87, 041406 (2013)ADSCrossRefGoogle Scholar
  14. 14.
    Gopalan, D.P., et al.: Formation of hexagonal boron nitride on graphene-covered copper surfaces. J. Mater. Res. 31, 945–958 (2016)ADSCrossRefGoogle Scholar
  15. 15.
    Vishwanath, S., et al.: Comprehensive structural and optical characterization of MBE grown MoSe2 on graphite, CaF2 and graphene. 2D Mater. 2, 024007 (2015)Google Scholar
  16. 16.
    Ohta, T., et al.: Interlayer interaction and electronic screening in multilayer graphene investigated with angle-resolved photoemission spectroscopy. Phys. Rev. Lett. 98, 206802 (2007)ADSCrossRefGoogle Scholar
  17. 17.
    Kopylov, S., Tzalenchuk, A., Kubatkin, S., Fal’ko, V.I.: Charge transfer between epitaxial graphene and silicon carbide. Appl. Phys. Lett. 97, 112109 (2010)ADSCrossRefGoogle Scholar
  18. 18.
    Mammadov, S., et al.: Polarization doping of graphene on silicon carbide. 2D Mater. 1, 035003 (2014)CrossRefGoogle Scholar
  19. 19.
    Kresse, G., Furthmüller, J.: Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B. 54, 11169–11186 (1996)ADSCrossRefGoogle Scholar
  20. 20.
    Kresse, G., Joubert, D.: From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B. 59, 1758–1775 (1999)ADSCrossRefGoogle Scholar
  21. 21.
    Ceperley, D.M., Alder, B.J.: Ground state of the electron gas by a stochastic method. Phys. Rev. Lett. 45, 566–569 (1980)ADSCrossRefGoogle Scholar
  22. 22.
    Hollander, M.J., et al.: Heterogeneous integration of hexagonal boron nitride on bilayer quasi-free-standing epitaxial graphene and its impact on electrical transport properties. Phys. Status solidi. 210, 1062–1070 (2013)ADSCrossRefGoogle Scholar
  23. 23.
    Yu, Y.-J., et al.: Tuning the graphene work function by electric field effect. Nano Lett. 9, 3430–3434 (2009)ADSCrossRefGoogle Scholar
  24. 24.
    Liu, G.-B., Shan, W.-Y., Yao, Y., Yao, W., Xiao, D.: Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides. Phys. Rev. B. 88, 085433 (2013)ADSCrossRefGoogle Scholar
  25. 25.
    McCann, E., Koshino, M.: The electronic properties of bilayer graphene. Reports Prog. Phys. 76, 056503 (2013)ADSCrossRefGoogle Scholar
  26. 26.
    (Oscar) Li, M., Esseni, D., Snider, G., Jena, D., Grace Xing, H.: Single particle transport in two-dimensional heterojunction interlayer tunneling field effect transistor. J. Appl. Phys. 115, 074508 (2014)ADSCrossRefGoogle Scholar
  27. 27.
    Liang, Y., Huang, S., Soklaski, R., Yang, L.: Quasiparticle band-edge energy and band offsets of monolayer of molybdenum and tungsten chalcogenides. Appl. Phys. Lett. 103, 042106 (2013)ADSCrossRefGoogle Scholar
  28. 28.
    He, K., et al.: Tightly bound excitons in monolayer WSe2. Phys. Rev. Lett. 113, 026803 (2014)Google Scholar
  29. 29.
    Zhang, C., et al.: Probing critical point energies of transition metal dichalcogenides: surprising indirect gap of single layer WSe2. Nano Lett. 15, 6494–6500 (2015)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

Personalised recommendations