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A library of atomically thin metal chalcogenides

Abstract

Investigations of two-dimensional transition-metal chalcogenides (TMCs) have recently revealed interesting physical phenomena, including the quantum spin Hall effect1,2, valley polarization3,4 and two-dimensional superconductivity5, suggesting potential applications for functional devices6,7,8,9,10. However, of the numerous compounds available, only a handful, such as Mo- and W-based TMCs, have been synthesized, typically via sulfurization11,12,13,14,15, selenization16,17 and tellurization18 of metals and metal compounds. Many TMCs are difficult to produce because of the high melting points of their metal and metal oxide precursors. Molten-salt-assisted methods have been used to produce ceramic powders at relatively low temperature19 and this approach20 was recently employed to facilitate the growth of monolayer WS2 and WSe2. Here we demonstrate that molten-salt-assisted chemical vapour deposition can be broadly applied for the synthesis of a wide variety of two-dimensional (atomically thin) TMCs. We synthesized 47 compounds, including 32 binary compounds (based on the transition metals Ti, Zr, Hf, V, Nb, Ta, Mo, W, Re, Pt, Pd and Fe), 13 alloys (including 11 ternary, one quaternary and one quinary), and two heterostructured compounds. We elaborate how the salt decreases the melting point of the reactants and facilitates the formation of intermediate products, increasing the overall reaction rate. Most of the synthesized materials in our library are useful, as supported by evidence of superconductivity in our monolayer NbSe2 and MoTe2 samples21,22 and of high mobilities in MoS2 and ReS2. Although the quality of some of the materials still requires development, our work opens up opportunities for studying the properties and potential application of a wide variety of two-dimensional TMCs.

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The authors declare no competing interests.

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References

  1. 1.

    Zhang, Y. B., Tan, Y. W., Stormer, H. L. & Kim, P. Experimental observation of the quantum Hall effect and Berry’s phase in graphene. Nature 438, 201–204 (2005).

  2. 2.

    Qian, X. F., Liu, J. W., Fu, L. & Li, J. Quantum spin Hall effect in two-dimensional transition metal dichalcogenides. Science 346, 1344–1347 (2014).

  3. 3.

    Xiao, D., Liu, G. B., Feng, W. X., Xu, X. D. & Yao, W. Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 108, 196802 (2012).

  4. 4.

    Zeng, H. L., Dai, J. F., Yao, W., Xiao, D. & Cui, X. D. Valley polarization in MoS2 monolayers by optical pumping. Nat. Nanotechnol. 7, 490–493 (2012).

  5. 5.

    Saito, Y., Nojima, T. & Iwasa, Y. Highly crystalline 2D superconductors. Nat. Rev. Mater. 2, 16094 (2017).

  6. 6.

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

  7. 7.

    Radisavljevic, B. & Kis, A. Mobility engineering and a metal-insulator transition in monolayer MoS2. Nat. Mater. 12, 815–820 (2013).

  8. 8.

    Wang, Q. H., Kalantar-Zadeh, K., Kis, A., Coleman, J. N. & Strano, M. S. Electronics and optoelectronics of two-dimensional transition metal dichalcogenides. Nat. Nanotechnol. 7, 699–712 (2012).

  9. 9.

    Roy, K. et al. Graphene-MoS2 hybrid structures for multifunctional photoresponsive memory devices. Nat. Nanotechnol. 8, 826–830 (2013).

  10. 10.

    Lopez-Sanchez, O., Lembke, D., Kayci, M., Radenovic, A. & Kis, A. Ultrasensitive photodetectors based on monolayer MoS2. Nat. Nanotechnol. 8, 497–501 (2013).

  11. 11.

    Zhan, Y. J., Liu, Z., Najmaei, S., Ajayan, P. M. & Lou, J. Large-area vapor-phase growth and characterization of MoS2 atomic layers on a SiO2 substrate. Small 8, 966–971 (2012).

  12. 12.

    van der Zande, A. M. et al. Grains and grain boundaries in highly crystalline monolayer molybdenum disulphide. Nat. Mater. 12, 554–561 (2013).

  13. 13.

    Lee, Y. H. et al. Synthesis of large-area MoS2 atomic layers with chemical vapor deposition. Adv. Mater. 24, 2320–2325 (2012).

  14. 14.

    Lin, Y. C. et al. Wafer-scale MoS2 thin layers prepared by MoO3 sulfurization. Nanoscale 4, 6637–6641 (2012).

  15. 15.

    Elías, A. L. et al. Controlled synthesis and transfer of large-area WS2 sheets: from single layer to few layers. ACS Nano 7, 5235–5242 (2013).

  16. 16.

    Lu, X. et al. Large-area synthesis of monolayer and few-layer MoSe2 films on SiO2 substrates. Nano Lett. 14, 2419–2425 (2014).

  17. 17.

    Huang, J. K. et al. Large-area synthesis of highly crystalline WSe2 monolayers and device applications. ACS Nano 8, 923–930 (2014).

  18. 18.

    Park, J. C. et al. Phase-engineered synthesis of centimeter-scale 1T′- and 2H-molybdenum ditelluride thin films. ACS Nano 9, 6548–6554 (2015).

  19. 19.

    Kimura, T. in Advances in Ceramics—Synthesis and Characterization Processing and Specific Applications (ed. Sikalidis, C.) Ch. 2 (InTech, London, 2011).

  20. 20.

    Li, S. S. et al. Halide-assisted atmospheric pressure growth of large WSe2 and WS2 monolayer crystals. Appl. Mater. Today 1, 60–66 (2015).

  21. 21.

    Xi, X. X. et al. Ising pairing in superconducting NbSe2 atomic layers. Nat. Phys. 12, 139–143 (2016).

  22. 22.

    Xi, X. X. et al. Strongly enhanced charge-density-wave order in monolayer NbSe2. Nat. Nanotechnol. 10, 765–769 (2015).

  23. 23.

    Dumcenco, D. et al. Large-area epitaxial monolayer MoS2. ACS Nano 9, 4611–4620 (2015).

  24. 24.

    Li, B. et al. Solid-vapor reaction growth of transition-metal dichalcogenide monolayers. Angew. Chem. Int. Ed. 55, 10656–10661 (2016).

  25. 25.

    Gong, Y. J. et al. Synthesis of millimeter-scale transition metal dichalcogenides single crystals. Adv. Funct. Mater. 26, 2009–2015 (2016).

  26. 26.

    Chen, Y. F. et al. Tunable band gap photoluminescence from atomically thin transition-metal dichalcogenide alloys. ACS Nano 7, 4610–4616 (2013).

  27. 27.

    Gong, Y. J. et al. Band gap engineering and layer-by-layer mapping of selenium-doped molybdenum disulfide. Nano Lett. 14, 442–449 (2014).

  28. 28.

    Lin, Z. et al. Facile synthesis of MoS2 and MoxW1 − xS2 triangular monolayers. APL Mater. 2, 092514 (2014).

  29. 29.

    Azizi, A. et al. Spontaneous formation of atomically thin stripes in transition metal dichalcogenide monolayers. Nano Lett. 16, 6982–6987 (2016).

  30. 30.

    Fei, L. et al. Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes. Nat. Commun. 7, 12206 (2016).

  31. 31.

    Wu, H.-M. & Chen, S.-A. Dopant-polymer interaction: WCl6 doped polyacetylene. Synth. Met. 20, 169–183 (1987).

  32. 32.

    Alov, N. V. XPS study of MoO3 and WO3 oxide surface modification by low-energy Ar+ ion bombardment. Phys. Stat. Solidi C 12, 263–266 (2015).

  33. 33.

    McGuire, G. E., Schweitz, Gk & Carlson, T. A. Study of core electron binding-energies in some group IIIA, VB, and VIB compounds. Inorg. Chem. 12, 2450–2453 (1973).

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Acknowledgements

This work was supported by the Singapore National Research Foundation under NRF award number NRF-NRFF2013-08, Tier 2 MOE2016-T2-2-153, MOE2016-T2-1-131, MOE2015-T2-2-007, Tier 1 RG164/15, Tier 1 RG4/17, CoE Industry Collaboration Grant WINTECH-NTU and the A*Star QTE programme. T.Y. acknowledges MOE Tier 1 RG100/15. J.L. and K.S. acknowledge the financial support of JST-ACCEL and JSPS KAKENHI (JP16H06333 and P16382). The work in SICCAS was supported by the National Key Research and Development Program of China (2016YFB0700204) and the National Natural Science Foundation of China (51502327). The work at IOP was supported by the Ministry of Science and Technology of China (grant numbers 2014CB920904, 2015CB921101 and 2016YFA0300600), the National Natural Science Foundation of China (grant numbers 11174340, 912212012, 11527806 and 91421303) and the Chinese Academy of Sciences (grant numbers XDB07010100). H.L. acknowledges the Singapore National Research Foundation for support under NRF award number NRF-NRFF2013-03. The work at Rice was supported by the US Department of Energy (DE-SC0012547) and by the R. Welch Foundation (C-1590).

Reviewer information

Nature thanks D. Akinwande, M. Terrones and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Author information

J.Z. and Z.L. designed the experiments. J.Z. grew all materials except TiSe2, NbSe2 and TaSe2. H.W. grew TiSe2, NbSe2 and TaSe2. Y.C., J.X., J.Z., T.Y. and Z.S. carried out Raman characterizations. J.L. and K.S. performed the STEM characterizations of all samples and analysis. J.Z. performed the AFM characterization of the samples. Y.Z., H.Y. and Q.L. performed the TG-DSC and XPS testing. Y.X., J.L. and B.I.Y. worked on ab initio reaction dynamics. C.-H.H., D.W. and H.L. performed electronic structure calculations. X.H., Q.Z., F.L. and Q.F. fabricated the devices. X.H., G.L., C.Y. and L.L. measured the superconductivity in MoTe2 and NbSe2. J.Z., J.L. and Z.L. wrote the paper. All authors discussed and commented on the manuscript.

Competing interests

The authors declare no competing interests.

Correspondence to Junhao Lin or Guangtong Liu or Zheng Liu.

Supplementary information

Supplementary Information

This file contains Supplementary Materials and Methods, Supplementary Text and Data, Supplementary Figures 1-63, Supplementary Tables 1-5 and Supplementary References – see contents page for details

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Further reading

Fig. 1: Flow chart of the general growth process for the production of TMCs by the chemical vapour deposition method.
Fig. 2: The transition metals and chalcogens used, and optical images of the resulting 47 different atomically thin TMCs and heterostructures.
Fig. 3: Atomic-resolution STEM images of representative monolayer materials in different phases.
Fig. 4: Reaction mechanism.

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