Abstract

Atomically thin two-dimensional semiconductors such as MoS2 hold great promise for electrical, optical and mechanical devices and display novel physical phenomena. However, the electron mobility of mono- and few-layer MoS2 has so far been substantially below theoretically predicted limits, which has hampered efforts to observe its intrinsic quantum transport behaviours. Potential sources of disorder and scattering include defects such as sulphur vacancies in the MoS2 itself as well as extrinsic sources such as charged impurities and remote optical phonons from oxide dielectrics. To reduce extrinsic scattering, we have developed here a van der Waals heterostructure device platform where MoS2 layers are fully encapsulated within hexagonal boron nitride and electrically contacted in a multi-terminal geometry using gate-tunable graphene electrodes. Magneto-transport measurements show dramatic improvements in performance, including a record-high Hall mobility reaching 34,000 cm2 V–1 s–1 for six-layer MoS2 at low temperature, confirming that low-temperature performance in previous studies was limited by extrinsic interfacial impurities rather than bulk defects in the MoS2. We also observed Shubnikov–de Haas oscillations in high-mobility monolayer and few-layer MoS2. Modelling of potential scattering sources and quantum lifetime analysis indicate that a combination of short-range and long-range interfacial scattering limits the low-temperature mobility of MoS2.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    , , , & Single-layer MoS2 transistors. Nature Nanotech. 6, 147–150 (2011).

  2. 2.

    et al. Flexible and transparent MoS2 field-effect transistors on hexagonal boron nitride–graphene heterostructures. ACS Nano 7, 7931–7936 (2013).

  3. 3.

    , , , & Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

  4. 4.

    et al. Atomically thin p–n junctions with van der Waals heterointerfaces. Nature Nanotech. 9, 676–681 (2014).

  5. 5.

    et al. Anomalous lattice vibrations of single- and few-layer MoS2. ACS Nano 4, 2695–2700 (2010).

  6. 6.

    et al. High-mobility and low-power thin-film transistors based on multilayer MoS2 crystals. Nature Commun. 3, 1011 (2012).

  7. 7.

    , , & High performance multilayer MoS2 with scandium contacts. Nano Lett. 13, 100–105 (2013).

  8. 8.

    , , & Intrinsic electronic transport properties of high-quality monolayer and bilayer MoS2. Nano Lett. 13, 4212–4216 (2013).

  9. 9.

    & Mobility engineering and a metal–insulator transition in monolayer MoS2. Nature Mater. 12, 815–820 (2013).

  10. 10.

    , , , & Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 108, 196802 (2012).

  11. 11.

    , , & Valleytronics. The valley Hall effect in MoS2 transistors. Science 344, 1489–1492 (2014).

  12. 12.

    , , , & Valley polarization in MoS2 monolayers by optical pumping. Nature Nanotech. 7, 490–493 (2012).

  13. 13.

    et al. Valley and band structure engineering of folded MoS2 bilayers. Nature Nanotech. 9, 825–829 (2014).

  14. 14.

    , , & Control of valley polarization in monolayer MoS2 by optical helicity. Nature Nanotech. 7, 494–498 (2012).

  15. 15.

    , , , & High mobility ambipolar MoS2 field-effect transistors: substrate and dielectric effects. Appl. Phys. Lett. 102, 042104 (2013).

  16. 16.

    , , , & Controlled charge trapping by molybdenum disulphide and graphene in ultrathin heterostructured memory devices. Nature Commun. 4, 1642 (2013).

  17. 17.

    et al. Integrated circuits based on bilayer MoS2 transistors. Nano Lett. 12, 4674–4680 (2012).

  18. 18.

    et al. Graphene/MoS2 hybrid technology for large-scale two-dimensional electronics. Nano Lett. 14, 3055–3063 (2014).

  19. 19.

    , , & Electroluminescence in single layer MoS2. Nano Lett. 13, 1416–1421 (2013).

  20. 20.

    et al. Strong light–matter interactions in heterostructures of atomically thin films. Science 340, 1311–1314 (2013).

  21. 21.

    et al. Highly flexible and transparent multilayer MoS2 transistors with graphene electrodes. Small 9, 3295–3300 (2013).

  22. 22.

    et al. Electrical characterization of back-gated bi-layer MoS2 field-effect transistors and the effect of ambient on their performances. Appl. Phys. Lett. 100, 123104 (2012).

  23. 23.

    , & Phonon-limited mobility in n-type single-layer MoS2 from first principles. Phys. Rev. B 85, 115317 (2012).

  24. 24.

    & Charge scattering and mobility in atomically thin semiconductors. Phys. Rev. X 4, 011043 (2014).

  25. 25.

    et al. Intrinsic electrical transport properties of monolayer silicene and MoS2 from first principles. Phys. Rev. B 87, 115418 (2013).

  26. 26.

    et al. Two-dimensional atomic crystals. Proc. Natl Acad. Sci. USA 102, 10451–10453 (2005).

  27. 27.

    , , , & Metallic 1T phase source/drain electrodes for field effect transistors from chemical vapor deposited MoS2. Appl. Phys. Lett. 2, 092516 (2014).

  28. 28.

    et al. Study on the resistance distribution at the contact between molybdenum disulfide and metals. ACS Nano 8, 7771–7779 (2014).

  29. 29.

    et al. Phase-engineered low-resistance contacts for ultrathin MoS2 transistors. Nature Mater. 13, 1128–1134 (2014).

  30. 30.

    et al. Transport properties of monolayer MoS2 grown by chemical vapor deposition. Nano Lett. 14, 1909–1913 (2014).

  31. 31.

    et al. Towards intrinsic charge transport in monolayer molybdenum disulfide by defect and interface engineering. Nature Commun. 5, 5290 (2014).

  32. 32.

    et al. Electronic transport and device prospects of monolayer molybdenum disulphide grown by chemical vapour deposition. Nature Commun. 5, 3078 (2014).

  33. 33.

    et al. Hopping transport through defect-induced localized states in molybdenum disulphide. Nature Commun. 4, 2642 (2013).

  34. 34.

    et al. One-dimensional electrical contact to a two-dimensional material. Science 342, 614–617 (2013).

  35. 35.

    et al. Field-effect transistors built from all two-dimensional material components. ACS Nano 8, 6256–6264 (2014).

  36. 36.

    , , , & Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices. Nature Mater. 11, 764–767 (2012).

  37. 37.

    et al. Grains and grain boundaries in highly crystalline monolayer molybdenum disulphide. Nature Mater. 12, 554–561 (2013).

  38. 38.

    , , & Contact research strategy for emerging molybdenum disulfide and other two-dimensional field-effect transistors. APL Mater. 2, 092510 (2014).

  39. 39.

    & Where does the current flow in two-dimensional layered systems? Nano Lett. 13, 3396–3402 (2013).

  40. 40.

    , & Channel length scaling of MoS2 MOSFETs. ACS Nano 6, 8563–8569 (2012).

  41. 41.

    et al. Switching mechanism in single-layer molybdenum disulfide transistors: an insight into current flow across Schottky barriers. ACS Nano 8, 1031–1038 (2013).

  42. 42.

    & Mobility of charge carriers in semiconducting layer structures. Phys. Rev. 163, 743755 (1967).

  43. 43.

    , , , & Intrinsic and extrinsic performance limits of graphene devices on SiO2. Nature Nanotech. 3, 206–209 (2008).

  44. 44.

    , & Electronic properties of two-dimensional systems. Rev. Mod. Phys. 54, 437–672 (1982).

  45. 45.

    , , & Electronic transport in two-dimensional graphene. Rev. Mod. Phys. 83, 407–470 (2011).

  46. 46.

    , , & Magneto-transport in MoS2: phase coherence, spin–orbit scattering, and the hall factor. ACS Nano 7, 7077–1082 (2013).

  47. 47.

    & Properties of semiconductor surface inversion layers in the electric quantum limit. Phys. Rev. 163, 816–835 (1967).

  48. 48.

    et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

  49. 49.

    et al. Electronic properties of graphene encapsulated with different two-dimensional atomic crystals. Nano Lett. 14, 3270–3276 (2014).

  50. 50.

    , , , & Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides. Phys. Rev. B 88, 085433 (2013).

Download references

Acknowledgements

This research was supported by the US National Science Foundation (NSF, DMR-1122594), the NSF MRSEC programme through Columbia in the Center for Precision Assembly of Superstratic and Superatomic Solids (DMR-1420634) and in part by the FAME Center, one of six centres of STARnet, a Semiconductor Research Corporation programme sponsored by MARCO and DARPA. G-H.L. was supported by the Basic Science Research Program (NRF-2014R1A1A1004632) through the National Research Foundation (NRF) funded by the Korean government Ministry of Science, ICT and Future Planning, and in part by the Yonsei University Future-Leading Research Initiative of 2014. P.Y.H. acknowledges support from the NSF Graduate Research Fellowship Program under grant DGE-0707428. Additional support was provided through funding and shared facilities via the Cornell Center for Materials Research NSF MRSEC programme (DMR-1120296). C.-H.L. was supported by Basic Science Research Program (NRF-2014R1A1A2055112) through the National Research Foundation (NRF) funded by the Korean Government Ministry of Education, and in part by the Korea Institute of Science and Technology Institutional Program (2Z04490). F.P. and B.S.J. acknowledge support from the Center for Nanostructured Graphene (CNG), which is funded by the Danish National Research Foundation (Project DNRF58). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by MEXT, Japan. T.T. acknowledges support from a Grant-in-Aid for Scientific Research (grant no. 262480621) and Innovative Areas ‘NanoInformatics’ (grant no. 25106006) from JSPS. The high magnetic field measurements were performed at NHMFL. The authors thank A. Suslov, B.J. Pullum, J. Billings and T. Murphy for assistance with the experiments at NHMFL.

Author information

Author notes

    • Xu Cui
    • , Gwan-Hyoung Lee
    •  & Young Duck Kim

    These authors contributed equally to this work

Affiliations

  1. Department of Mechanical Engineering, Columbia University, New York, New York 10027, USA

    • Xu Cui
    • , Young Duck Kim
    • , Ghidewon Arefe
    • , Daniel A. Chenet
    • , Xian Zhang
    • , Lei Wang
    •  & James Hone
  2. Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Republic of Korea

    • Gwan-Hyoung Lee
  3. School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

    • Pinshane Y. Huang
    •  & David A. Muller
  4. KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701, Republic of Korea

    • Chul-Ho Lee
  5. Department of Material Science and Engineering, Columbia University, New York, New York 10027, USA

    • Fan Ye
  6. Center for Nanostructured Graphene (CNG), DTU Nanotech, Technical University of Denmark, Ørsteds Plads, 345E, Kgs. Lyngby 2800, Denmark

    • Filippo Pizzocchero
    •  & Bjarke S. Jessen
  7. National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan

    • Kenji Watanabe
    •  & Takashi Taniguchi
  8. Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA

    • David A. Muller
  9. Department of Electrical & Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA

    • Tony Low
  10. Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA

    • Philip Kim

Authors

  1. Search for Xu Cui in:

  2. Search for Gwan-Hyoung Lee in:

  3. Search for Young Duck Kim in:

  4. Search for Ghidewon Arefe in:

  5. Search for Pinshane Y. Huang in:

  6. Search for Chul-Ho Lee in:

  7. Search for Daniel A. Chenet in:

  8. Search for Xian Zhang in:

  9. Search for Lei Wang in:

  10. Search for Fan Ye in:

  11. Search for Filippo Pizzocchero in:

  12. Search for Bjarke S. Jessen in:

  13. Search for Kenji Watanabe in:

  14. Search for Takashi Taniguchi in:

  15. Search for David A. Muller in:

  16. Search for Tony Low in:

  17. Search for Philip Kim in:

  18. Search for James Hone in:

Contributions

X.C. and G-H.L. designed the research project and supervised the experiment. X.C., G-H.L., Y.D.K., G.A., C-H.L., F.Y., F.P., B.S.J. and L.W. fabricated the devices. X.C., G-H.L. and Y.D.K. performed device measurements with supervision from P.K. and J.H. X.C., G-H.L., G.A. and X.Z. performed optical spectroscopy and data analysis. D.A.C. grew and prepared the CVD MoS2 sample. T.L. performed theoretical calculations. K.W. and T.T. prepared hBN samples. P.Y.H. and D.A.M. performed TEM analyses. X.C., G-H.L., Y.D.K. and J.H. analysed the data and wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Gwan-Hyoung Lee or James Hone.

Supplementary information

PDF files

  1. 1.

    Supplementary information

    Supplementary information

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nnano.2015.70

Further reading