Skip to main content

Thank you for visiting 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.

Filtering the photoluminescence spectra of atomically thin semiconductors with graphene


Atomically thin semiconductors made from transition metal dichalcogenides (TMDs) are model systems for investigations of strong light–matter interactions and applications in nanophotonics, optoelectronics and valleytronics. However, the photoluminescence spectra of TMD monolayers display a large number of features that are particularly challenging to decipher. On a practical level, monochromatic TMD-based emitters would be beneficial for low-dimensional devices, but this challenge is yet to be resolved. Here, we show that graphene, directly stacked onto TMD monolayers, enables single and narrow-line photoluminescence arising solely from TMD neutral excitons. This filtering effect stems from complete neutralization of the TMD by graphene, combined with selective non-radiative transfer of long-lived excitonic species to graphene. Our approach is applied to four tungsten- and molybdenum-based TMDs and establishes TMD/graphene heterostructures as a unique set of optoelectronic building blocks that are suitable for electroluminescent systems emitting visible and near-infrared photons at near THz rate with linewidths approaching the homogeneous limit.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Graphene as a versatile emission filter.
Fig. 2: Neutralizing an atomically thin semiconductor with graphene.
Fig. 3: Laser power-dependent PL in BN-capped TMD/graphene at 4 K.
Fig. 4: Low-temperature exciton dynamics.
Fig. 5: Evidence for hot exciton transfer to graphene.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


  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).

    Google Scholar 

  2. 2.

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

    CAS  Google Scholar 

  3. 3.

    Wang, G. et al. Colloquium: excitons in atomically thin transition metal dichalcogenides. Rev. Mod. Phys. 90, 021001 (2018).

    CAS  Google Scholar 

  4. 4.

    Goryca, M. et al. Revealing exciton masses and dielectric properties of monolayer semiconductors with high magnetic fields. Nat. Commun. 10, 4172 (2019).

    CAS  Google Scholar 

  5. 5.

    Palummo, M., Bernardi, M. & Grossman, J. C. Exciton radiative lifetimes in two-dimensional transition metal dichalcogenides. Nano Lett. 15, 2794–2800 (2015).

    CAS  Google Scholar 

  6. 6.

    Robert, C. et al. Exciton radiative lifetime in transition metal dichalcogenide monolayers. Phys. Rev. B 93, 205423 (2016).

    Google Scholar 

  7. 7.

    Fang, H. H. et al. Control of the exciton radiative lifetime in van der Waals heterostructures. Phys. Rev. Lett. 123, 067401 (2019).

    CAS  Google Scholar 

  8. 8.

    Mak, K. F. et al. Tightly bound trions in monolayer MoS2. Nat. Mater. 12, 207–211 (2013).

    CAS  Google Scholar 

  9. 9.

    Ross, J. S. et al. Electrical control of neutral and charged excitons in a monolayer semiconductor. Nat. Commun. 4, 1474 (2013).

    Google Scholar 

  10. 10.

    Courtade, E. et al. Charged excitons in monolayer WSe2: experiment and theory. Phys. Rev. B 96, 085302 (2017).

    Google Scholar 

  11. 11.

    Echeverry, J. P., Urbaszek, B., Amand, T., Marie, X. & Gerber, I. C. Splitting between bright and dark excitons in transition metal dichalcogenide monolayers. Phys. Rev. B 93, 121107 (2016).

    Google Scholar 

  12. 12.

    Barbone, M. et al. Charge-tuneable biexciton complexes in monolayer WSe2. Nat. Commun. 9, 3721 (2018).

    Google Scholar 

  13. 13.

    Ye, Z. et al. Efficient generation of neutral and charged biexcitons in encapsulated WSe2 monolayers. Nat. Commun. 9, 3718 (2018).

    Google Scholar 

  14. 14.

    Paur, M. et al. Electroluminescence from multi-particle exciton complexes in transition metal dichalcogenide semiconductors. Nat. Commun. 10, 1709 (2019).

    Google Scholar 

  15. 15.

    Li, Z. et al. Revealing the biexciton and trion–exciton complexes in BN encapsulated WSe2. Nat. Commun. 9, 3719 (2018).

    Google Scholar 

  16. 16.

    Vaclavkova, D. et al. Singlet and triplet trions in WS2 monolayer encapsulated in hexagonal boron nitride. Nanotechnology 29, 325705 (2018).

    CAS  Google Scholar 

  17. 17.

    Robert, C. et al. Fine structure and lifetime of dark excitons in transition metal dichalcogenide monolayers. Phys. Rev. B 96, 155423 (2017).

    Google Scholar 

  18. 18.

    Zhou, Y. et al. Probing dark excitons in atomically thin semiconductors via near-field coupling to surface plasmon polaritons. Nat. Nanotechnol. 12, 856–860 (2017).

    CAS  Google Scholar 

  19. 19.

    Zhang, X.-X. et al. Magnetic brightening and control of dark excitons in monolayer WSe2. Nat. Nanotechnol. 12, 883–888 (2017).

    CAS  Google Scholar 

  20. 20.

    Lagarde, D. et al. Carrier and polarization dynamics in monolayer MoS2. Phys. Rev. Lett. 112, 047401 (2014).

    CAS  Google Scholar 

  21. 21.

    Lindlau, J. et al. The role of momentum-dark excitons in the elementary optical response of bilayer WSe2. Nat. Commun. 9, 2586 (2018).

    Google Scholar 

  22. 22.

    Liu, E. et al. Valley-selective chiral phonon replicas of dark excitons and trions in monolayer WSe2. Phys. Rev. Res. 1, 032007 (2019).

    Google Scholar 

  23. 23.

    Cadiz, F. et al. Excitonic linewidth approaching the homogeneous limit in MoS2-based van der Waals heterostructures. Phys. Rev. X 7, 021026 (2017).

    Google Scholar 

  24. 24.

    Ajayi, O. A. et al. Approaching the intrinsic photoluminescence linewidth in transition metal dichalcogenide monolayers. 2D Mater. 4, 031011 (2017).

    Google Scholar 

  25. 25.

    Scuri, G. et al. Large excitonic reflectivity of monolayer MoSe2 encapsulated in hexagonal boron nitride. Phys. Rev. Lett. 120, 037402 (2018).

    CAS  Google Scholar 

  26. 26.

    Back, P., Zeytinoglu, S., Ijaz, A., Kroner, M. & Imamoğlu, A. Realization of an electrically tunable narrow-bandwidth atomically thin mirror using monolayer MoSe2. Phys. Rev. Lett. 120, 037401 (2018).

    CAS  Google Scholar 

  27. 27.

    CastroNeto, A. H., Guinea, F., Peres, N. M. R., Novoselov, K. S. & Geim, A. K. The electronic properties of graphene. Rev. Mod. Phys. 81, 109–162 (2009).

    CAS  Google Scholar 

  28. 28.

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

    Google Scholar 

  29. 29.

    Hill, H. M. et al. Exciton broadening in WS2/graphene heterostructures. Phys. Rev. B 96, 205401 (2017).

    Google Scholar 

  30. 30.

    Froehlicher, G., Lorchat, E. & Berciaud, S. Charge versus energy transfer in atomically thin graphene–transition metal dichalcogenide van der Waals heterostructures. Phys. Rev. X 8, 011007 (2018).

    CAS  Google Scholar 

  31. 31.

    He, J. et al. Electron transfer and coupling in graphene–tungsten disulfide van der Waals heterostructures. Nat. Commun. 5, 5622 (2014).

    CAS  Google Scholar 

  32. 32.

    Yuan, L. et al. Photocarrier generation from interlayer charge-transfer transitions in WS2–graphene heterostructures. Sci. Adv. 4, e1700324 (2018).

    Google Scholar 

  33. 33.

    Selig, M., Malic, E., Ahn, K. J., Koch, N. & Knorr, A. Theory of optically induced Förster coupling in van der Waals coupled heterostructures. Phys. Rev. B 99, 035420 (2019).

    CAS  Google Scholar 

  34. 34.

    Basko, D., LaRocca, G., Bassani, F. & Agranovich, V. Förster energy transfer from a semiconductor quantum well to an organic material overlayer. Eur. Phys. J. B 8, 353–362 (1999).

    CAS  Google Scholar 

  35. 35.

    Massicotte, M. et al. Picosecond photoresponse in van der Waals heterostructures. Nat. Nanotechnol. 11, 42–46 (2016).

    CAS  Google Scholar 

  36. 36.

    Luo, Y. K. et al. Opto-valleytronic spin injection in monolayer MoS2/few-layer graphene hybrid spin valves. Nano Lett. 17, 3877–3883 (2017).

    CAS  Google Scholar 

  37. 37.

    Avsar, A. et al. Optospintronics in graphene via proximity coupling. ACS Nano 11, 11678–11686 (2017).

    CAS  Google Scholar 

  38. 38.

    Raja, A. et al. Coulomb engineering of the bandgap and excitons in two-dimensional materials. Nat. Commun. 8, 15251 (2017).

    Google Scholar 

  39. 39.

    Nagler, P. et al. Zeeman splitting and inverted polarization of biexciton emission in monolayer WS2. Phys. Rev. Lett. 121, 057402 (2018).

    CAS  Google Scholar 

  40. 40.

    Li, Y. et al. Measurement of the optical dielectric function of monolayer transition-metal dichalcogenides: MoS2, MoSe2, WS2, and WSe2. Phys. Rev. B 90, 205422 (2014).

    Google Scholar 

  41. 41.

    Hao, K. et al. Neutral and charged inter-valley biexcitons in monolayer MoSe2. Nat. Commun. 8, 15552 (2017).

    CAS  Google Scholar 

  42. 42.

    Yuma, B. et al. Biexciton, single carrier, and trion generation dynamics in single-walled carbon nanotubes. Phys. Rev. B 87, 205412 (2013).

    Google Scholar 

  43. 43.

    Mouri, S. et al. Nonlinear photoluminescence in atomically thin layered WSe2 arising from diffusion-assisted exciton–exciton annihilation. Phys. Rev. B 90, 155449 (2014).

    Google Scholar 

  44. 44.

    Cadiz, F. et al. Ultra-low power threshold for laser induced changes in optical properties of 2D molybdenum dichalcogenides. 2D Mater. 3, 045008 (2016).

    Google Scholar 

  45. 45.

    Steinleitner, P. et al. Direct observation of ultrafast exciton formation in a monolayer of WSe2. Nano Lett. 17, 1455–1460 (2017).

    Google Scholar 

  46. 46.

    Arp, T. B., Pleskot, D., Aji, V. & Gabor, N. M. Electron–hole liquid in a van der Waals heterostructure photocell at room temperature. Nat. Photon. 13, 245–250 (2019).

    CAS  Google Scholar 

  47. 47.

    Schneider, C., Glazov, M. M., Korn, T., Höfling, S. & Urbaszek, B. Two-dimensional semiconductors in the regime of strong light–matter coupling. Nat. Commun. 9, 2695 (2018).

    Google Scholar 

  48. 48.

    Chervy, T. et al. Room temperature chiral coupling of valley excitons with spin-momentum locked surface plasmons. ACS Photonics 5, 1281–1287 (2018).

    Google Scholar 

  49. 49.

    Mak, K. F., Xiao, D. & Shan, J. Light–valley interactions in 2D semiconductors. Nat. Photon. 12, 451–460 (2018).

    CAS  Google Scholar 

  50. 50.

    Lorchat, E. et al. Room-temperature valley polarization and coherence in transition metal dichalcogenide–graphene van der Waals heterostructures. ACS Photonics 5, 5047–5054 (2018).

    Google Scholar 

  51. 51.

    Castellanos-Gomez, A. et al. Deterministic transfer of two-dimensional materials by all-dry viscoelastic stamping. 2D Mater. 1, 011002 (2014).

    Google Scholar 

  52. 52.

    Zomer, P. J., Guimarães, M. H. D., Brant, J. C., Tombros, N. & van Wees, B. J. Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride. Appl. Phys. Lett. 105, 013101 (2014).

    Google Scholar 

Download references


We thank D. Basko, T. Galvani, L. Wirtz, G. Schull, S. Azzini, T. Chervy, C. Genet, M.A. Semina and M.M. Glazov for fruitful discussions. We are grateful to H. Majjad and M. Rastei for help with AFM measurements, to M. Romeo, F. Chevrier, M. Acosta, A. Boulard and the StNano clean room staff for technical support. We acknowledge financial support from the Agence Nationale de la Recherche (under grants H2DH ANR-15-CE24-0016, 2D-POEM ANR-18-ERC1-0009, D-vdW-Spin, VallEx and MagicValley), from LabEx NIE (grant no. ANR-11-LABX-0058-NIE) and from EUR NanoX (grant no. VWspin and MILO).

Author information




S.B. conceived and led the project, with C.R., D.L. and X.M. supervising the time-resolved PL measurements. E.L. and L.E.P.L. fabricated the samples. E.L., L.E.P.L., C.R., D.L. and S.B. carried out the measurements. E.L., L.E.P.L. and S.B. analysed the data, with input from G.F., C.R., D.L. and X.M. T.T. and K.W. provided high-quality hexagonal BN crystals. S.B. wrote the manuscript, with input from X.M., C.R., E.L. and L.E.P.L.

Corresponding author

Correspondence to Stéphane Berciaud.

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

Extended Data Fig. 1 Approaching the homogeneous limit in BN/MoSe2/graphene.

Photoluminescence (PL) spectra of a MoSe2 monolayer directly deposited on hexagonal boron nitride (BN) (top, blue line), partly covered by a single layer of graphene (1LG middle, orange) and by a bilayer of graphene (2LG, bottom, dark red). The X0 exciton energy, full-width at half-maximum (FWHM, denoted \({\Gamma }_{{{\rm{X}}}^{0}}\)) and integrated PL intensity (I\({}_{{{\rm{X}}}^{0}}\), in arbitrary units) are indicated. The spectra were recorded at T=15 K with laser photon energy of 2.33 eV. We observe nearly identical \({\Gamma }_{{{\rm{X}}}^{0}}\), as small as 1.9 meV and 2.0 meV in the 1LG/MoSe2/BN and 2LG/MoSe2/BN, respectively. We find that I\({}_{{{\rm{X}}}^{0}}\) is only quenched by a factor 2.2 (resp. 3.0) in 1LG/MoSe2/BN (resp. 2LG/MoSe2/BN) with respect to the vacuum/MoSe2/BN reference. These results demonstrate that minimal X0 PL quenching and PL linewidths approaching the homogeneous limit can be achieved in MoSe2/graphene heterostructures without the need for an extra BN top layer. This figure appears as supplementary Fig. 2 in the supplementary information file.

Extended Data Fig. 2 Trion-free photoluminescence spectra at room temperature.

PL spectra of BN-capped TMD/graphene heterostructures compared to those of a nearby BN-capped TMD reference, all recorded in ambient air in the linear regime under continuous-wave laser excitation at 2.33 eV. The X0 PL lines are symmetric in the TMD/graphene heterostructures whereas they exhibit a lower-energy shoulder arising predominantly from trions (X) in the TMD references. The scaling factors allow estimating the large room temperature PL quenching factors that strongly contrast with the low X0 PL quenching factors observed at cryogenic temperatures (see main text and supplementary Table 1). The X0 lines are slightly redshifted in TMD/graphene, as discussed in the main text and supplementary Section 4. The red lines are multi-Lorentzian fits to the data, with their different components shown with grey dashed lines. Hot luminescence from excited excitonic states (for example, X\({}_{2{\rm{s}}}^{0}\) and B excitons) is clearly visible in MoS2/graphene and MoSe2/graphene. This figure appears as supplementary Fig. 7 in the supplementary information file.

Extended Data Fig. 3 Photostability and neutrality under high photon flux at room temperature.

(a) Laser power-dependent photoluminescence spectra of a BN-capped WS2/graphene heterostructure compared to a nearby BN-capped WS2 reference, recorded in ambient air using continuous-wave laser excitation at 2.33 eV. The spectra are shown on a semilogarithmic scale and are normalised by the incoming photon flux (Φph) and the integration time. Φph is color-coded with a gradient ranging from dark red (low Φph ~ 100 nW/μm2 or equivalently ~ 3 × 1019cm2s−1) to yellow (high Φph ~ 1mW∕μm2 or equivalently ~ 3 × 1023cm2s−1). PL saturation due to exciton–exciton annihilation is clearly visible in WS2, whereas a quasi linear scaling is observed in WS2/graphene. The PL spectra in WS2 remain quasi symmetric even under high Φph, while the PL spectra from the TMD reference exhibit a lower-energy shoulder, assigned to trion (X) emission. The latter grows significantly as Φph increases and ultimately overcomes the X0 line, as shown in (b) on the selected spectra recorded at Φph ~ 2 × 1023cm2s−1 and plotted on a linear scale. This figure appears as supplementary Fig. 8 in the supplementary information file.

Supplementary information

Supplementary Information

Supplementary Figs. 1–14, Tables 1 and 2, Sections 1–9 and refs. 1–18.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Lorchat, E., López, L.E.P., Robert, C. et al. Filtering the photoluminescence spectra of atomically thin semiconductors with graphene. Nat. Nanotechnol. 15, 283–288 (2020).

Download citation

Further reading


Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research