Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Strain distributions and their influence on electronic structures of WSe2–MoS2 laterally strained heterojunctions

Nature Nanotechnology volume 13, pages 152–158 (2018)Cite this article

Subjects

Abstract

Monolayer transition metal dichalcogenide heterojunctions, including vertical and lateral p–n junctions, have attracted considerable attention due to their potential applications in electronics and optoelectronics. Lattice-misfit strain in atomically abrupt lateral heterojunctions, such as WSe2–MoS2, offers a new band-engineering strategy for tailoring their electronic properties. However, this approach requires an understanding of the strain distribution and its effect on band alignment. Here, we study a WSe2–MoS2 lateral heterojunction using scanning tunnelling microscopy and image its moiré pattern to map the full two-dimensional strain tensor with high spatial resolution. Using scanning tunnelling spectroscopy, we measure both the strain and the band alignment of the WSe2–MoS2 lateral heterojunction. We find that the misfit strain induces type II to type I band alignment transformation. Scanning transmission electron microscopy reveals the dislocations at the interface that partially relieve the strain. Finally, we observe a distinctive electronic structure at the interface due to hetero-bonding.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: STM images of the WSe2–MoS2 lateral heterojunction.
Fig. 2: Imaging the anisotropic strain in the WSe2–MoS2 lateral heterojunction.
Fig. 3: The electronic structure and its dependence on the strain distribution.
Fig. 4: Determinations of band edges, interface states and band alignment by constant I spectroscopy.

Similar content being viewed by others

References

  1. Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: A new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

    Article  Google Scholar 

  2. Splendiani, A. et al. Emerging photoluminescence in monolayer MoS2. Nano Lett. 10, 1271–1275 (2010).

    Article  Google Scholar 

  3. Duan, X. D., Wang, C., Pan, A. L., Yu, R. Q. & Duan, X. F. Two-dimensional transition metal dichalcogenides as atomically thin semiconductors: opportunities and challenges. Chem. Soc. Rev. 44, 8859–8876 (2015).

    Article  Google Scholar 

  4. Liu, G. B., Xiao, D., Yao, Y. G., Xu, X. D. & Yao, W. Electronic structures and theoretical modelling of two-dimensional group-VIB transition metal dichalcogenides. Chem. Soc. Rev. 44, 2643–2663 (2015).

    Article  Google Scholar 

  5. Mak, K. F. & Shan, J. Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides. Nat. Photon. 10, 216–226 (2016).

    Article  Google Scholar 

  6. Fang, H. et al. Strong interlayer coupling in van der Waals heterostructures built from single-layer chalcogenides. Proc. Natl Acad. Sci. USA 111, 6198–6202 (2014).

    Article  Google Scholar 

  7. Tongay, S. et al. Tuning interlayer coupling in large-area heterostructures with CVD-grown MoS2 and WS2 monolayers. Nano Lett. 14, 3185–3190 (2014).

    Article  Google Scholar 

  8. Hong, X. et al. Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures. Nat. Nanotech. 9, 682–686 (2014).

    Article  Google Scholar 

  9. Chiu, M.-H. et al. Determination of band alignment in the single-layer MoS2/WSe2 heterojunction. Nat. Commun. 6, 7666 (2015).

    Article  Google Scholar 

  10. Wilson, N. R. et al. Determination of band offsets, hybridization, and exciton binding in 2D semiconductor heterostructures. Sci. Adv. 3, e1601832 (2017).

    Article  Google Scholar 

  11. Huang, C. et al. Lateral heterojunctions within monolayer MoSe2–WSe2 semiconductors. Nat. Mater. 13, 1096–1101 (2014).

    Article  Google Scholar 

  12. Gong, Y. J. et al. Vertical and in-plane heterostructures from WS2/MoS2 monolayers. Nat. Mater. 13, 1135–1142 (2014).

    Article  Google Scholar 

  13. Duan, X. et al. Lateral epitaxial growth of two-dimensional layered semiconductor heterojunctions. Nat. Nanotech. 9, 1024–1030 (2014).

    Article  Google Scholar 

  14. Li, M.-Y. et al. Epitaxial growth of a monolayer WSe2-MoS2 lateral p-n junction with an atomically sharp interface. Science 349, 524–528 (2015).

    Article  Google Scholar 

  15. Yun, W. S., Han, S. W., Hong, S. C., Kim, I. G. & Lee, J. D. Thickness and strain effects on electronic structures of transition metal dichalcogenides: 2H-MX2 semiconductors (M = Mo, W; X = S, Se, Te). Phys. Rev. B 85, 033305 (2012).

    Article  Google Scholar 

  16. Johari, P. & Shenoy, V. B. Tuning the electronic properties of semiconducting transitionmetal dichalcogenides by applying mechanical strains. ACS Nano 6, 5449–5456 (2012).

    Article  Google Scholar 

  17. Li, H. et al. Optoelectronic crystal of artificial atoms in strain-textured molybdenum disulphide. Nat. Commun. 6, 7381 (2015).

    Article  Google Scholar 

  18. Shi, H., Pan, H., Zhang, Y. W. & Yakobson, B. I. Quasiparticle band structures and optical properties of strained monolayer MoS2 and WS2. Phys. Rev. B 87, 155304 (2013).

    Article  Google Scholar 

  19. Liu, Z. et al. Strain and structure heterogeneity in MoS2 atomic layers grown by chemical vapour deposition. Nat. Commun. 5, 5246 (2014).

    Article  Google Scholar 

  20. Hui, Y. Y. et al. Exceptional tunability of band energy in a compressively strained trilayer MoS2 sheet. ACS Nano 7, 7126–7131 (2013).

    Article  Google Scholar 

  21. Feng, J., Qian, X., Huang, C.-W. & Li, J. Strain-engineered artificial atom as a broad-spectrum solar energy funnel. Nat. Photon. 6, 866–872 (2012).

    Article  Google Scholar 

  22. He, K., Poole, C., Mak, K. F. & Shan, J. Experimental demonstration of continuous electronic structure tuning via strain in atomically thin MoS2. Nano Lett. 13, 2931–2936 (2013).

    Article  Google Scholar 

  23. Zhu, C. R. et al. Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS2. Phys. Rev. B 88, 121301 (2013).

    Article  Google Scholar 

  24. Rice, C. et al. Raman-scattering measurements and first-principles calculations of strain-induced phonon shifts in monolayer MoS2. Phys. Rev. B 87, 081307 (2013).

    Article  Google Scholar 

  25. Castellanos-Gomez, A. et al. Local strain engineering in atomically thin MoS2. Nano Lett. 13, 5361–5366 (2013).

    Article  Google Scholar 

  26. Conley, H. J. et al. Bandgap engineering of strained monolayer and bilayer MoS2. Nano Lett. 13, 3626–3630 (2013).

    Article  Google Scholar 

  27. Liu, N., Tersoff, J., Baklenov, O., Holmes, A. L. & Shih, C. K. Nonuniform composition profile in In0.5Ga0.5As alloy quantum dots. Phys. Rev. Lett. 84, 334–337 (2000).

    Article  Google Scholar 

  28. Cosma, D. A., Wallbank, J. R., Cheianov, V. & Fal’ko, V. I. Moiré pattern as a magnifying glass for strain and dislocations in van der Waals heterostructures. Faraday Discuss. 173, 137–143 (2014).

    Google Scholar 

  29. Jiang, Y. et al. Visualizing strain-induced pseudomagnetic fields in graphene through an hBN magnifying glass. Nano Lett. 17, 2839–2843 (2017).

    Article  Google Scholar 

  30. Zhang, C. et al. Interlayer couplings, Moiré patterns, and 2D electronic superlattices in MoS2/WSe2 hetero-bilayers. Sci. Adv. 3, e1601459 (2017).

    Article  Google Scholar 

  31. Goodier, J. N. Concentration of stress around spherical and cylindrical inclusions and flaws. J. Appl. Mech. Trans. ASME 55, 39–44 (1933).

    Google Scholar 

  32. Kang, J., Tongay, S., Zhou, J., Li, J. & Wu, J. Band offsets and heterostructures of two-dimensional semiconductors. Appl. Phys. Lett. 102, 012111 (2013).

    Article  Google Scholar 

  33. Guzman, D. M. & Strachan, A. Role of strain on electronic and mechanical response of semiconducting transition-metal dichalcogenide monolayers: An ab-initio study. J. Appl. Phys. 115, 243701 (2014).

    Article  Google Scholar 

  34. 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).

    Article  Google Scholar 

  35. Park, J. et al. Spatially resolved one-dimensional boundary states in graphene–hexagonal boron nitride planar heterostructures. Nat. Commun. 5, 5403 (2014).

    Article  Google Scholar 

Download references

Acknowledgements

This research was supported with grants from the Welch Foundation (F-1672), the US National Science Foundation (NSF) (DMR-1306878, EFMA-1542747) and the Materials Research Science and Engineering Center (DMR-1720595). L.J.L. acknowledges support from KAUST (Saudi Arabia), MOST and TCECM, Academia Sinica (Taiwan) and AOARD FA23861510001 (USA). C.Z acknowledges support from the National Natural Science Foundation of China (Grant No. 11774268). Y.S.S acknowledges support from the Yan Jici Talent Students Program. This work made use of the electron microscopy facility of the Cornell Center for Materials Research with support from the NSF (DMR-1719875 and DMR-1429155).

Author information

Authors and Affiliations

  1. Department of Physics, University of Texas at Austin, Austin, TX, USA

    Chendong Zhang, Yushan Su & Chih-Kang Shih

  2. School of Physics and Technology, Wuhan University, Wuhan, China

    Chendong Zhang

  3. Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia

    Ming-Yang Li & Lain-Jong Li

  4. Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan

    Ming-Yang Li

  5. IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY, USA

    Jerry Tersoff

  6. School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA

    Yimo Han & David A. Muller

  7. School of the Gifted Young, University of Science and Technology of China, Hefei, Anhui, China

    Yushan Su

  8. Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, USA

    David A. Muller

Authors
  1. Chendong Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Ming-Yang Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Jerry Tersoff
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Yimo Han
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Yushan Su
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Lain-Jong Li
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. David A. Muller
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Chih-Kang Shih
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

C.Z. carried out the STM/S measurements. M.-Y.L. and L.-J.L. performed the chemical vapour deposition growth of WSe2–MoS2 heterojunctions. Y.S. helped determine strain tensors from distorted moiré patterns. Y.H. and D.A.M. performed the scanning transmission electron microscopy investigations. J.T. identified the mechanisms of strain relaxation and explained the strain distribution. C.-K.S. advised on the experiments and provided input on the data analysis. C.-K.S. and C.Z. wrote the paper with input from the co-authors.

Corresponding authors

Correspondence to Chendong Zhang or Chih-Kang Shih.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Electronic supplementary material

Supplementary Information

Supplementary Figures 1–12, Supplementary references

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Zhang, C., Li, MY., Tersoff, J. et al. Strain distributions and their influence on electronic structures of WSe2–MoS2 laterally strained heterojunctions. Nature Nanotech 13, 152–158 (2018). https://doi.org/10.1038/s41565-017-0022-x

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41565-017-0022-x

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing