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.

Interlayer exciton laser of extended spatial coherence in atomically thin heterostructures

Abstract

Two-dimensional semiconductors have emerged as a new class of materials for nanophotonics owing to their strong exciton–photon interaction1,2 and their ability to be engineered and integrated into devices3. Here we take advantage of these properties to engineer an efficient lasing medium based on direct-bandgap interlayer excitons in rotationally aligned atomically thin heterostructures4. Lasing is measured from a transition-metal dichalcogenide heterobilayer (WSe2–MoSe2) integrated in a silicon nitride grating resonator. An abrupt increase in the spatial coherence of the emission is observed across the lasing threshold. The work establishes interlayer excitons in two-dimensional heterostructures as a gain medium with spatially coherent lasing emission and potential for heterogeneous integration. With electrically tunable exciton–photon interaction strengths5 and long-range dipolar interactions, these interlayer excitons are promising for application as low-power, ultrafast lasers and modulators and for the study of many-body quantum phenomena6.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Illustration of the heterobilayer/grating-cavity laser system.
Fig. 2: Properties of the heterobilayer and grating cavity.
Fig. 3: Spectral properties of the interlayer exciton laser.
Fig. 4: First-order coherence of the interlayer exciton laser.

Data availability

Data that support the findings of this study are available from the corresponding author on reasonable request.

References

  1. 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).

    ADS  Article  Google Scholar 

  2. 2.

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

    ADS  CAS  Article  Google Scholar 

  3. 3.

    Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2013).

    CAS  Article  Google Scholar 

  4. 4.

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

    ADS  Article  Google Scholar 

  5. 5.

    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).

    ADS  CAS  Article  Google Scholar 

  6. 6.

    Fogler, M. M., Butov, L. V. & Novoselov, K. S. High-temperature superfluidity with indirect excitons in van der Waals heterostructures. Nat. Commun. 5, 4555 (2014).

    ADS  CAS  Article  Google Scholar 

  7. 7.

    Eaton, S. W., Fu, A., Wong, A. B., Ning, C. Z. & Yang, P. Semiconductor nanowire lasers. Nat. Rev. Mater. 1, 16028 (2016).

    ADS  CAS  Article  Google Scholar 

  8. 8.

    Noginov, M. A. et al. Demonstration of a spaser-based nanolaser. Nature 460, 1110–1112 (2009).

    ADS  CAS  Article  Google Scholar 

  9. 9.

    Noda, S. Seeking the ultimate nanolaser. Science 314, 260–261 (2006).

    CAS  Article  Google Scholar 

  10. 10.

    Wu, S. et al. Monolayer semiconductor nanocavity lasers with ultralow thresholds. Nature 520, 69–72 (2015).

    ADS  CAS  Article  Google Scholar 

  11. 11.

    Ye, Y. et al. Monolayer excitonic laser. Nat. Photon. 9, 733–737 (2015).

    ADS  CAS  Article  Google Scholar 

  12. 12.

    Salehzadeh, O., Djavid, M., Tran, N. H., Shih, I. & Mi, Z. Optically pumped two-dimensional MoS2 lasers operating at room-temperature. Nano Lett. 15, 5302–5306 (2015).

    ADS  CAS  Article  Google Scholar 

  13. 13.

    Li, Y. et al. Room-temperature continuous-wave lasing from monolayer molybdenum ditelluride integrated with a silicon nanobeam cavity. Nat. Nanotechnol. 12, 987–992 (2017).

    ADS  CAS  Article  Google Scholar 

  14. 14.

    Shang, J. et al. Room-temperature 2D semiconductor activated vertical-cavity surface-emitting lasers. Nat. Commun. 8, 543 (2017).

    ADS  Article  Google Scholar 

  15. 15.

    Zhao, L. et al. High-temperature continuous-wave pumped lasing from large-area monolayer semiconductors grown by chemical vapor deposition. ACS Nano 12, 9390–9396 (2018).

    CAS  Article  Google Scholar 

  16. 16.

    Reeves, L., Wang, Y. & Krauss, T. F. 2D material microcavity light emitters: to lase or not to lase? Adv. Opt. Mater. 6, 1800272 (2018).

    Article  Google Scholar 

  17. 17.

    Butov, L. V., Zrenner, A., Abstreiter, G., Böhm, G. & Weimann, G. Condensation of indirect excitons in coupled AlAs/GaAs quantum wells. Phys. Rev. Lett. 73, 304–307 (1994).

    ADS  CAS  Article  Google Scholar 

  18. 18.

    Rigosi, A. F., Hill, H. M., Li, Y., Chernikov, A. & Heinz, T. F. Probing interlayer interactions in transition metal dichalcogenide heterostructures by optical spectroscopy: MoS2/WS2 and MoSe2/WSe2. Nano Lett. 15, 5033–5038 (2015).

    ADS  CAS  Article  Google Scholar 

  19. 19.

    Zhang, L. et al. Highly valley-polarized singlet and triplet interlayer excitons in van der Waals heterostructure. Phys. Rev. B 100, 041402 (2019).

    ADS  CAS  Article  Google Scholar 

  20. 20.

    Lee, C. H. et al. Atomically thin p-n junctions with van der Waals heterointerfaces. Nat. Nanotechnol. 9, 676–681 (2014).

    ADS  CAS  Article  Google Scholar 

  21. 21.

    Ross, J. S. et al. Interlayer exciton optoelectronics in a 2D heterostructure p-n junction. Nano Lett. 17, 638–643 (2017).

    ADS  CAS  Article  Google Scholar 

  22. 22.

    Zhang, L., Gogna, R., Burg, W., Tutuc, E. & Deng, H. Photonic-crystal exciton-polaritons in monolayer semiconductors. Nat. Commun. 9, 713 (2018).

    ADS  Article  Google Scholar 

  23. 23.

    Spivak, B. & Luryi, S. in Future Trends in Microelectronics (eds Spivak, B., Luryi, S. & Zaslavsky, A.) 68–76 (Wiley-Blackwell, 2007).

  24. 24.

    Deng, H., Solomon, G. S., Hey, R., Ploog, K. H. & Yamamoto, Y. Spatial coherence of a polariton condensate. Phys. Rev. Lett. 99, 126403 (2007).

    ADS  Article  Google Scholar 

  25. 25.

    Hoang, T. B., Akselrod, G. M., Yang, A., Odom, T. W. & Mikkelsen, M. H. Millimeter-scale spatial coherence from a plasmon laser. Nano Lett. 17, 6690–6695 (2017).

    ADS  CAS  Article  Google Scholar 

  26. 26.

    Daskalakis, K. S., Maier, S. A. & Kéna-Cohen, S. Spatial coherence and stability in a disordered organic polariton condensate. Phys. Rev. Lett. 115, 035301 (2015).

    ADS  CAS  Article  Google Scholar 

  27. 27.

    Yu, H., Liu, G.-B., Tang, J., Xu, X. & Yao, W. Moiré excitons: from programmable quantum emitter arrays to spin-orbit–coupled artificial lattices. Sci. Adv. 3, e1701696 (2017).

    ADS  Article  Google Scholar 

  28. 28.

    Wu, F., Lovorn, T. & MacDonald, A. H. Theory of optical absorption by interlayer excitons in transition metal dichalcogenide heterobilayers. Phys. Rev. B 97, 035306 (2018).

    ADS  CAS  Article  Google Scholar 

  29. 29.

    Tran, K. et al. Evidence for moiré excitons in van der Waals heterostructures. Nature 567, 71–75 (2019).

    ADS  CAS  Article  Google Scholar 

  30. 30.

    Seyler, K. L. et al. Signatures of moiré-trapped valley excitons in MoSe2/WSe2 heterobilayers. Nature 567, 66–70 (2019).

    ADS  CAS  Article  Google Scholar 

  31. 31.

    Jin, C. et al. Observation of moiré excitons in WSe2/WS2 heterostructure superlattices. Nature 567, 76–80 (2019); correction 569, E7 (2019).

    ADS  CAS  Article  Google Scholar 

  32. 32.

    Kirstaedter, N. et al. Low threshold, large To injection laser emission from (InGa)As quantum dots. Electron. Lett. 30, 1416–1417 (1994).

    CAS  Article  Google Scholar 

  33. 33.

    Shahnazaryan, V., Kyriienko, O. & Shelykh, I. A. Adiabatic preparation of a cold exciton condensate. Phys. Rev. B 91, 085302 (2015).

    ADS  Article  Google Scholar 

  34. 34.

    Jin, Z., Li, X., Mullen, J. T. & Kim, K. W. Intrinsic transport properties of electrons and holes in monolayer transition-metal dichalcogenides. Phys. Rev. B 90, 045422 (2014).

    ADS  Article  Google Scholar 

Download references

Acknowledgements

We acknowledge support from the Army Research Office under awards W911NF-17-1-0312. H.D. acknowledges support from the Asian Office of Aerospace R&D under awards FA2386-18-1-4086. E.T. acknowledges support from Intel Corp., and the Welch Foundation grant F-2018-20190330.

Author information

Affiliations

Authors

Contributions

E.Y.P. performed the measurements of the indirect exciton laser. L.Z. designed, fabricated and characterized the grating cavity. L.Z. exfoliated and characterized the WSe2 and MoSe2 monolayers with help from E.Y.P. G.W.B. made the rotationally aligned structure. R.G., E.Y.P. and L.Z. performed simulations of the device. H.D. and E.T. supervised the project. E.Y.P., L.Z. and H.D. performed data analysis and wrote the manuscript with input from all authors.

Corresponding author

Correspondence to Hui Deng.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Extended data figures and tables

Extended Data Fig. 1 Heterobilayer twist angle.

a, b, Optical image (a) and angle-resolved SHG measurements (b; open circles) of WSe2/MoSe2 heterobilayers. c, d, As a, b but for a different sample. The field of view of the optical images is around 60 μm. Solid lines in b, d, are fits by a cos2(3θ) function, which give relative twist angles of 0.22°± 1.78° for b, and 0.34° ± 1.5° for d.

Extended Data Fig. 2 Interlayer exciton lifetime.

a, Time-resolved PL spectrum for TM emission. b, Line-cut of a near 1.38 eV. Red line is a bi-exponential fit to the data, with a fitted lifetime of 2 ns.

Extended Data Fig. 3 Spatial mapping of PL.

The normalized intensity of PL from the device is shown as a function of position. Spectral filters centred around their respective exciton peak energies were applied for each image. The white contours mark the regions of heterobilayer (a), MoSe2 (b) and WSe2 (c).

Extended Data Fig. 4 Electric field profiles.

Shown are simulated normalized electric field profiles as a function of position near the centre of a grating cavity with lateral dimensions of 100 μm × 100 μm. a, TE-polarized light at the cavity resonance at k = 0, showing strong field enhancement in the grating layer including at its surface where the heterobilayer is placed. b, TM-polarized light at the same wavelength as a, showing negligible cavity effects. White lines outline different layers of the grating cavity. The corresponding enhancement of the exciton radiative decay rate, or the Purcell factor, is calculated to be around 2.4.

Extended Data Fig. 5 Power-dependence reproducibility.

The photon occupancy (red) and linewidth (blue) of TE emission from the heterobilayer versus input pump power, similar to that shown in Fig. 3b of the main text but measured on a different day to show the reproducibility of the device. The error bars on the photon occupancy data include the shot noise and detector read noise. The error bars on the linewidth data correspond to the 95% confidence interval of the Lorentzian fit.

Extended Data Fig. 6 Rate equation fitting.

The log–log plot of photon occupancy versus pump power. The diamonds represent measured data shown in Fig. 3b of the main text, and the solid line is a rate-equation fitting. Details of the rate equation simulation are described in Methods.

Extended Data Fig. 7 Temperature dependence.

Temperature-dependent real space PL spectra of the sample studied in the main text.

Extended Data Fig. 8 Experimental setup.

Schematic diagram of the optical experimental setup as described in Methods. BS, beam splitter; LP, long-pass filter; BP, band-pass filter; CCD, charge-coupled device.

Extended Data Fig. 9 Temporal coherence.

Shown are temporal coherence interference fringes at g(1)(τ = 0) measured using a two-retro-reflector Michelson interferometer under CW excitation above threshold. a, Interferogram image at τ = 0. b, Horizontal line-cut of a around y = 1.5 μm. The red line is a fit to the Gaussian pump beam profile modulated by a cosine function. Here g(1)(τ = 0) = 0.78.

Extended Data Table 1 Rate equation fitting parameters

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Paik, E.Y., Zhang, L., Burg, G.W. et al. Interlayer exciton laser of extended spatial coherence in atomically thin heterostructures. Nature 576, 80–84 (2019). https://doi.org/10.1038/s41586-019-1779-x

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

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