Superlubricity of epitaxial monolayer WS2 on graphene


We report the superlubric sliding of monolayer tungsten disulfide (WS2) on epitaxial graphene (EG) grown on silicon carbide (SiC). Single-crystalline WS2 flakes with lateral size of hundreds of nanometers are obtained via chemical vapor deposition (CVD) on EG. Microscopic and diffraction analyses indicate that the WS2/EG stack is predominantly aligned with zero azimuthal rotation. The present experiments show that, when perturbed by a scanning probe microscopy (SPM) tip, the WS2 flakes are prone to slide over the graphene surfaces at room temperature. Atomistic force field-based molecular dynamics simulations indicate that, through local physical deformation of the WS2 flake, the scanning tip releases enough energy to the flake to overcome the motion activation barrier and trigger an ultralow-friction rototranslational displacement, that is superlubric. Experimental observations show that, after sliding, the WS2 flakes come to rest with a rotation of nπ/3 with respect to graphene. Moreover, atomically resolved measurements show that the interface is atomically sharp and the WS2 lattice is strain-free. These results help to shed light on nanotribological phenomena in van der Waals (vdW) heterostacks, and suggest that the applicative potential of the WS2/graphene heterostructure can be extended by novel mechanical prospects.

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  • 16 August 2018

    The article Superlubricity of epitaxial monolayer WS<Subscript>2</Subscript> on graphene, written by Holger Büch, Antonio Rossi, Stiven Forti, Domenica Convertino, Valentina Tozzini, and Camilla Coletti, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on June 18th 2018 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed in August 2018 to © The Author(s) 2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (<ExternalRef><RefSource></RefSource><RefTarget Address="" TargetType="URL"/></ExternalRef>), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.

    The original article has been corrected.


  1. [1]

    Lotsch, B. V. Vertical 2D heterostructures. Annu. Rev. Mater. Res. 2015, 45, 85–109.

  2. [2]

    Novoselov, K. S.; Mishchenko, A.; Carvalho, A.; Castro Neto, A. H. 2D materials and van der Waals heterostructures. Science 2016, 353, aac9439.

  3. [3]

    Liu, L. T.; Kumar, S. B.; Ouyang, Y. J.; Guo, J. Performance limits of monolayer transition metal dichalcogenide transistors. IEEE Trans. Electron Devices 2011, 58: 3042–3047.

  4. [4]

    Cheng, L.; Huang, W. J.; Gong, Q. F.; Liu, C. H.; Liu, Z.; Li, Y. G.; Dai, H. J. Ultrathin WS2 nanoflakes as a highperformance electrocatalyst for the hydrogen evolution reaction. Angew. Chem., Int. Ed. 2014, 53: 7860–7863.

  5. [5]

    Forti, S.; Rossi, A.; Büch, H.; Cavallucci, T.; Bisio, F.; Sala, A.; Menteş, T. O.; Locatelli, A.; Magnozzi, M.; Canepa, M. et al. Electronic properties of single-layer tungsten disulfide on epitaxial graphene on silicon carbide. Nanoscale 2017, 9: 16412–16419.

  6. [6]

    Dendzik, M.; Michiardi, M.; Sanders, C.; Bianchi, M.; Miwa, J. A.; Grønborg, S. S.; Lauritsen, J. V.; Bruix, A.; Hammer, B.; Hofmann, P. Growth and electronic structure of epitaxial single-layer WS2 on Au(111). Phys. Rev. B 2015, 92, 245442.

  7. [7]

    Georgiou, T.; Jalil, R.; Belle, B. D.; Britnell, L.; Gorbachev, R. V.; Morozov, S. V.; Kim, Y. J.; Gholinia, A.; Haigh, S. J.; Makarovsky, O. et al. Vertical field-effect transistor based on graphene-WS2 heterostructures for flexible and transparent electronics. Nat. Nanotechnol.2013, 8: 100–103.

  8. [8]

    Mehew, J. D.; Unal, S.; Torres Alonso, E.; Jones, G. F.; Fadhil Ramadhan, S.; Craciun, M. F.; Russo, S. Fast and highly sensitive ionic-polymer-gated WS2-graphene photodetectors. Adv. Mater. 2017, 29, 1700222.

  9. [9]

    Rossi, A.; Spirito, D.; Bianco, F.; Forti, S.; Fabbri, F.; Büch, H.; Tredicucci, A.; Krahne, R.; Coletti, C. Patterned tungsten disulfide/graphene heterostructures for efficient multifunctional optoelectronic devices. Nanoscale 2018, 10: 4332–4338.

  10. [10]

    Zheng, Q. S.; Jiang, B.; Liu, S. P.; Weng, Y. X.; Lu, L.; Xue, Q. K.; Zhu, J.; Jiang, Q.; Wang, S.; Peng, L. M. Selfretracting motion of graphite microflakes. Phys. Rev. Lett. 2008, 100, 067205.

  11. [11]

    Liu, Z.; Yang, J. R.; Grey, F.; Liu, J. Z.; Liu, Y. L.; Wang, Y. B.; Yang, Y. L.; Cheng, Y.; Zheng, Q. S. Observation of microscale superlubricity in graphite. Phys. Rev. Lett. 2012, 108, 205503.

  12. [12]

    Martin, J. M.; Donnet, C.; Le Mogne, T.; Epicier, T. Superlubricity of molybdenum disulphide. Phys. Rev. B 1993, 48: 10583–10586.

  13. [13]

    Oviedo, J. P.; KC, S.; Lu, N.; Wang, J. G.; Cho, K.; Wallace, R. M.; Kim, M. J. In situ TEM characterization of shear-stress-induced interlayer sliding in the cross section view of molybdenum disulfide. ACS Nano 2015, 9: 1543–1551.

  14. [14]

    Hirano, M.; Shinjo, K. Atomistic locking and friction. Phys. Rev. B 1990, 41: 11837–11851.

  15. [15]

    Hirano, M.; Shinjo, K. Superlubricity and frictional anisotropy. Wear 1993, 168: 121–125.

  16. [16]

    Hirano, M.; Shinjo, K.; Kaneko, R.; Murata, Y. Observation of superlubricity by scanning tunneling microscopy. Phys. Rev. Lett. 1997, 78: 1448–1451.

  17. [17]

    Hod, O. The registry index: A quantitative measure of materials’ interfacial commensurability. ChemPhysChem 2013, 14: 2376–2391.

  18. [18]

    Kontorova, T. A.; Frenkel, J. On the theory of plastic deformation and twinning. II. Zh. Eksp. Teor. Fiz. 1938, 8: 1340–1348.

  19. [19]

    Guerra, R.; van Wijk, M.; Vanossi, A.; Fasolino, A.; Tosatti, E. Graphene on h-BN: To align or not to align? Nanoscale 2017, 9: 8799–8804.

  20. [20]

    Dienwiebel, M.; Verhoeven, G. S.; Pradeep, N.; Frenken, J. W. M.; Heimberg, J. A.; Zandbergen, H. W. Superlubricity of graphite. Phys. Rev. Lett. 2004, 92, 126101.

  21. [21]

    Feng, X. F.; Kwon, S.; Park, J. Y.; Salmeron, M. Superlubric sliding of graphene nanoflakes on graphene. ACS Nano 2013, 7: 1718–1724.

  22. [22]

    Li, H.; Wang, J. H.; Gao, S.; Chen, Q.; Peng, L. M.; Liu, K. H.; Wei, X. L. Superlubricity between MoS2 monolayers. Adv. Mater. 2017, 29, 1701474.

  23. [23]

    Liu, S.-W.; Wang, H.-P.; Xu, Q.; Ma, T.-B.; Yu, G.; Zhang, C. H.; Geng, D. C.; Yu, Z. W.; Zhang, S. G.; Wang, W. Z. et al. Robust microscale superlubricity under high contact pressure enabled by graphene-coated microsphere. Nat. Commun. 2017, 8, 14029.

  24. [24]

    Wang, D. M.; Chen, G. R.; Li, C. K.; Cheng, M.; Yang, W.; Wu, S.; Xie, G. B.; Zhang, J.; Zhao, J.; Lu, X. B. et al. Thermally induced graphene rotation on hexagonal boron nitride. Phys. Rev. Lett. 2016, 116, 126101.

  25. [25]

    Wang, L. F.; Zhou, X.; Ma, T. B.; Liu, D. M.; Gao, L.; Li, X.; Zhang, J.; Hu, Y. Z.; Wang, H.; Dai, Y. D. et al. Superlubricity of a graphene/MoS2 heterostructure: A combined experimental and DFT study. Nanoscale 2017, 9: 10846–10853.

  26. [26]

    Leven, I.; Krepel, D.; Shemesh, O.; Hod, O. Robust superlubricity in graphene/h-BN heterojunctions. J. Phys. Chem. Lett. 2013, 4: 115–120.

  27. [27]

    Rossi, A.; Büch, H.; Di Rienzo, C.; Miseikis, V.; Convertino, D.; Al-Temimy, A.; Voliani, V.; Gemmi, M.; Piazza, V.; Coletti, C. Scalable synthesis of WS2 on graphene and h-BN: An all-2D platform for light-matter transduction. 2D Mater. 2016, 3, 31013.

  28. [28]

    Goler, S.; Coletti, C.; Piazza, V.; Pingue, P.; Colangelo, F.; Pellegrini, V.; Emtsev, K. V.; Forti, S.; Starke, U.; Beltram, F. et al. Revealing the atomic structure of the buffer layer between SiC(0001) and epitaxial graphene. Carbon 2013, 51: 249–254.

  29. [29]

    Necas, D.; Klapetek, P. Gwyddion: An open-source software for SPM data analysis. Cent. Eur. J. Phys. 2012, 10: 181–188.

  30. [30]

    Smith, W.; Forester, T. R. DL_POLY_2.0: A generalpurpose parallel molecular dynamics simulation package. J. Mol. Graph. 1996, 14: 136–141.

  31. [31]

    Miwa, J. A.; Dendzik, M.; Grønborg, S. S.; Bianchi, M.; Lauritsen, J. V.; Hofmann, P.; Ulstrup, S. Van der Waals epitaxy of two-dimensional MoS2–graphene heterostructures in ultrahigh vacuum. ACS Nano 2015, 9: 6502–6510.

  32. [32]

    Liu, X. L.; Balla, I.; Bergeron, H.; Campbell, G. P.; Bedzyk, M. J.; Hersam, M. C. Rotationally commensurate growth of MoS2 on epitaxial graphene. ACS Nano 2016, 10: 1067–1075.

  33. [33]

    Zhang, C. D.; 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. 2014, 14: 2443–2447.

  34. [34]

    Huang, Y. L.; Chen, Y. F.; Zhang, W. J.; Quek, S. Y.; Chen, C. H.; Li, L. J.; Hsu, W. T.; Chang, W. H.; Zheng, Y. J.; Chen, W. et al. Bandgap tunability at single-layer molybdenum disulphide grain boundaries. Nat. Commun. 2015, 6, 6298.

  35. [35]

    Pierucci, D.; Henck, H.; Avila, J.; Balan, A.; Naylor, C. H.; Patriarche, G.; Dappe, Y. J.; Silly, M. G.; Sirotti, F.; Johnson, A. T. C. et al. Band alignment and minigaps in monolayer MoS2-graphene van der Waals heterostructures. Nano Lett. 2016, 7: 4054–4061.

  36. [36]

    Xu, P.; Yang, Y. R.; Qi, D.; Barber, S. D.; Schoelz, J. K.; Ackerman, M. L.; Bellaiche, L.; Thibado, P. M. Electronic transition from graphite to graphene via controlled movement of the top layer with scanning tunneling microscopy. Phys. Rev. B 2012, 86: 085428.

  37. [37]

    Xu, P.; Ackerman, M. L.; Barber, S. D.; Schoelz, J. K.; Qi, D. J.; Thibado, P. M.; Wheeler, V. D.; Nyakiti, L. O.; Myers-Ward, R. L.; Eddy, C. R., Jr. et al. Graphene manipulation on 4H-SiC (0001) using scanning tunneling microscopy. Jpn. J. Appl. Phys. 2013, 52: 035104.

  38. [38]

    Kobayashi, Y.; Taniguchi, T.; Watanabe, K.; Maniwa, Y.; Miyata, Y. Slidable atomic layers in van der Waals heterostructures. Appl. Phys. Express 2017, 10: 045201.

  39. [39]

    de Heer, W. A.; Berger, C.; Wu, X. S.; First, P. N.; Conrad, E. H.; Li, X. B.; Li, T. B.; Sprinkle, M.; Hass, J.; Sadowski, M. L. et al. Epitaxial graphene. Solid State Commun. 2007, 143, 92–100.

  40. [40]

    Lauffer, P.; Emtsev, K. V.; Graupner, R.; Seyller, T.; Ley, L.; Reshanov, S. A.; Weber, H. B. Atomic and electronic structure of few-layer graphene on SiC(0001) studied with scanning tunneling microscopy and spectroscopy. Phys. Rev. B 2008, 77: 155426.

  41. [41]

    Perea-López, N.; Lin, Z.; Pradhan, N. R.; Iñiguez-Rábago, A.; Laura Elías, A.; McCreary, A.; Lou, J.; Ajayan, P. M.; Terrones, H.; Balicas, L. et al. CVD-grown monolayered MoS2 as an effective photosensor operating at low-voltage. 2D Mater. 2014, 1: 011004.

  42. [42]

    Yoshida, S.; Kobayashi, Y.; Sakurada, R.; Mori, S.; Miyata, Y.; Mogi, H.; Koyama, T.; Takeuchi, O.; Shigekawa, H. Microscopic basis for the band engineering of Mo1-xWxS2-based heterojunction. Sci. Rep. 2015, 5: 14808.

  43. [43]

    Lin, Z.; Carvalho, B. R.; Kahn, E.; Lv, R. T.; Rao, R.; Terrones, H.; Pimenta, M. A.; Terrones, M. Defect engineering of two-dimensional transition metal dichalcogenides. 2D Mater. 2016, 3: 022002.

  44. [44]

    Parkin, W. M.; Balan, A.; Liang, L. B.; Das, P. M.; Lamparski, M.; Naylor, C. H.; Rodríguez-Manzo, J. A.; Johnson, A. T. C.; Meunier, V.; Drndic, M. Raman shifts in electron-irradiated monolayer MoS2. ACS Nano 2016, 10: 4134–4142.

  45. [45]

    Fabbri, F.; Rotunno, E.; Cinquanta, E.; Campi, D.; Bonnini, E.; Kaplan, D.; Lazzarini, L.; Bernasconi, M.; Ferrari, C.; Longo, M. et al. Novel near-infrared emission from crystal defects in MoS2 multilayer flakes. Nat. Commun. 2016, 7, 13044.

  46. [46]

    Kormányos, A.; Burkard, G.; Gmitra, M.; Fabian, J.; Zólyomi, V.; Drummond, N. D.; Fal’ko, V. Corrigendum: k.p theory for two-dimensional transition metal dichalcogenide semiconductors (2015 2D Mater. 2 022001). 2D Mater. 2015, 2, 049501.

  47. [47]

    Liu, X. L.; Balla, I.; Bergeron, H.; Hersam, M. C. Point defects and grain boundaries in rotationally commensurate MoS2 on epitaxial graphene. J. Phys. Chem. C 2016, 120, 20798–20805.

  48. [48]

    González, C.; Biel, B.; Dappe, Y. J. Theoretical characterisation of point defects on a MoS2 monolayer by scanning tunnelling microscopy. Nanotechnology 2016, 27: 105702.

  49. [49]

    Füchtbauer, H. G.; Tuxen, A. K.; Moses, P. G.; Topsøe, H.; Besenbacher, F.; Lauritsen, J. V. Morphology and atomicscale structure of single-layer WS2 nanoclusters. Phys. Chem. Chem. Phys. 2013, 15: 15971–15980.

  50. [50]

    Dong, Y. L.; Wu, X. W.; Martini, A. Atomic roughness enhanced friction on hydrogenated graphene. Nanotechnology 2013, 24, 375701.

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We wish to thank Professor Annalisa Fasolino for useful discussions and suggestions. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement Nos. 696656 – GrapheneCore1 and 785219 – GrapheneCore2.

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Correspondence to Camilla Coletti.

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The original version of this article was revised to add the missing Open Access designation.

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Büch, H., Rossi, A., Forti, S. et al. Superlubricity of epitaxial monolayer WS2 on graphene. Nano Res. 11, 5946–5956 (2018) doi:10.1007/s12274-018-2108-7

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  • superlubricity
  • graphene
  • tungsten disulfide
  • scanning tunneling
  • microscopy (STM)
  • two-dimensional (2D) materials
  • nanomechanical