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:

Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect

Abstract

Excitons, Coulomb-bound electron–hole pairs, are elementary photo-excitations in semiconductors that can couple to light through radiative relaxation. In contrast, dark excitons (XD) show anti-parallel spin configuration with generally forbidden radiative emission. Because of their long lifetimes, these dark excitons are appealing candidates for quantum computing and optoelectronics. However, optical read-out and control of XD states has remained challenging due to their decoupling from light. Here, we present a tip-enhanced nano-optical approach to induce, switch and programmably modulate the XD emission at room temperature. Using a monolayer transition metal dichalcogenide (TMD) WSe2 on a gold substrate, we demonstrate ~6 × 105-fold enhancement in dark exciton photoluminescence quantum yield achieved through coupling of the antenna-tip to the dark exciton out-of-plane optical dipole moment, with a large Purcell factor of ≥2 × 103 of the tip–sample nano-cavity. Our approach provides a facile way to harness excitonic properties in low-dimensional semiconductors offering new strategies for quantum optoelectronics.

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

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

Fig. 1: Schematic of tip-enhanced photoluminescence spectroscopy and electronic band structure of monolayer WSe2.
Fig. 2: Probing radiative emission of dark excitons of monolayer WSe2 through polarization- and power-dependence of tip-enhanced photoluminescence.
Fig. 3: Active control of tip-induced radiative emission of dark excitons of monolayer WSe2.
Fig. 4: Switching and modulation of dark exciton emission.

Similar content being viewed by others

References

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

    Article  Google Scholar 

  2. 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 

  3. He, K. et al. Tightly bound excitons in monolayer WSe2. Phys. Rev. Lett. 113, 026803 (2014).

    Article  Google Scholar 

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

    Article  Google Scholar 

  5. Basov, D., Fogler, M. & de Abajo, F. G. Polaritons in van der Waals materials. Science 354, aag1992 (2016).

    Article  Google Scholar 

  6. Tong, Q. et al. Topological mosaics in moire superlattices of van der Waals heterobilayers. Nat. Phys. 13, 356–362 (2017).

    Article  Google Scholar 

  7. Hao, K. et al. Direct measurement of exciton valley coherence in monolayer WSe2. Nat. Phys. 12, 677–682 (2016).

    Article  Google Scholar 

  8. Liu, G.-B., Shan, W.-Y., Yao, Y., Yao, W. & Xiao, D. Three-band tight-binding model for monolayers of group-vib transition metal dichalcogenides. Phys. Rev. B 88, 085433 (2013).

    Article  Google Scholar 

  9. Kośmider, K., González, J. W. & Fernández-Rossier, J. Large spin splitting in the conduction band of transition metal dichalcogenide monolayers. Phys. Rev. B 88, 245436 (2013).

    Article  Google Scholar 

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

    Article  Google Scholar 

  11. Zhang, X.-X., You, Y., Zhao, S. Y. F. & Heinz, T. F. Experimental evidence for dark excitons in monolayer WSe2. Phys. Rev. Lett. 115, 257403 (2015).

    Article  Google Scholar 

  12. Arora, A. et al. Excitonic resonances in thin films of WSe2: from monolayer to bulk material. Nanoscale 7, 10421–10429 (2015).

    Article  Google Scholar 

  13. Koperski, M. et al. Optical properties of atomically thin transition metal dichalcogenides: observations and puzzles. Nanophotonics 6, 1289–1308 (2017).

    Article  Google Scholar 

  14. Slobodeniuk, A. & Basko, D. Spin-flip processes and radiative decay of dark intravalley excitons in transition metal dichalcogenide monolayers. 2D Mater 3, 035009 (2016).

    Article  Google Scholar 

  15. Molas, M. et al. Brightening of dark excitons in monolayers of semiconducting transition metal dichalcogenides. 2D Mater 4, 021003 (2017).

    Article  Google Scholar 

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

    Article  Google Scholar 

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

    Article  Google Scholar 

  18. Wang, G. et al. In-plane propagation of light in transition metal dichalcogenide monolayers: optical selection rules. Phys. Rev. Lett. 119, 047401 (2017).

    Article  Google Scholar 

  19. Smoleński, T., Kazimierczuk, T., Goryca, M., Wojnar, P. & Kossacki, P. Mechanism and dynamics of biexciton formation from a long-lived dark exciton in a CdTe quantum dot. Phys. Rev. B 91, 155430 (2015).

    Article  Google Scholar 

  20. Poem, E. et al. Accessing the dark exciton with light. Nat. Phys. 6, 993–997 (2010).

    Article  Google Scholar 

  21. Combescot, M., Betbeder-Matibet, O. & Combescot, R. Bose–Einstein condensation in semiconductors: the key role of dark excitons. Phys. Rev. Lett. 99, 176403 (2007).

    Article  Google Scholar 

  22. Nirmal, M. et al. Observation of the ‘dark exciton’ in CdSe quantum dots. Phys. Rev. Lett. 75, 3728 (1995).

    Article  Google Scholar 

  23. Smoleński, T. et al. In-plane radiative recombination channel of a dark exciton in self-assembled quantum dots. Phys. Rev. B 86, 241305 (2012).

    Article  Google Scholar 

  24. Kravtsov, V., Berweger, S., Atkin, J. M. & Raschke, M. B. Control of plasmon emission and dynamics at the transition from classical to quantum coupling. Nano Lett. 14, 5270–5275 (2014).

    Article  Google Scholar 

  25. Park, K.-D. et al. Hybrid tip-enhanced nanospectroscopy and nanoimaging of monolayer WSe2 with local strain control. Nano Lett. 16, 2621–2627 (2016).

    Article  Google Scholar 

  26. Wang, Z. et al. Giant photoluminescence enhancement in tungsten-diselenide–gold plasmonic hybrid structures. Nat. Commun. 7, 11283 (2016).

    Article  Google Scholar 

  27. You, Y. et al. Observation of biexcitons in monolayer WSe2. Nat. Phys. 11, 477–481 (2015).

    Article  Google Scholar 

  28. Kühn, S., Håkanson, U., Rogobete, L. & Sandoghdar, V. Enhancement of single-molecule fluorescence using a gold nanoparticle as an optical nanoantenna. Phys. Rev. Lett. 97, 017402 (2006).

    Article  Google Scholar 

  29. Anger, P., Bharadwaj, P. & Novotny, L. Enhancement and quenching of single-molecule fluorescence. Phys. Rev. Lett. 96, 113002 (2006).

    Article  Google Scholar 

  30. Park, K.-D. et al. A new method of Q factor optimization by introducing two nodal wedges in a tuning-fork/fiber probe distance sensor. Rev. Sci. Instrum. 81, 093702 (2010).

    Article  Google Scholar 

  31. Bychkov, Y. A. & Rashba, E. I. Oscillatory effects and the magnetic susceptibility of carriers in inversion layers. J. Phys. C Solid State Phys. 17, 6039 (1984).

    Article  Google Scholar 

  32. Ochoa, H. & Roldán, R. Spin-orbit-mediated spin relaxation in monolayer MoS2. Phys. Rev. B 87, 245421 (2013).

    Article  Google Scholar 

  33. Akselrod, G. M. et al. Probing the mechanisms of large purcell enhancement in plasmonic nanoantennas. Nat. Photon. 8, 835–840 (2014).

    Article  Google Scholar 

  34. Rose, A. et al. Control of radiative processes using tunable plasmonic nanopatch antennas. Nano Lett. 14, 4797–4802 (2014).

    Article  Google Scholar 

  35. Crooker, S., Barrick, T., Hollingsworth, J. & Klimov, V. Multiple temperature regimes of radiative decay in CdSe nanocrystal quantum dots: intrinsic limits to the dark-exciton lifetime. Appl. Phys. Lett. 82, 2793–2795 (2003).

    Article  Google Scholar 

  36. Chikkaraddy, R. et al. Single-molecule strong coupling at room temperature in plasmonic nanocavities. Nature 535, 127–130 (2016).

    Article  Google Scholar 

  37. Kleemann, M.-E. et al. Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature. Preprint at https://arxiv.org/abs/1704.02756 (2017).

  38. Jin, C. et al. Interlayer electron-phonon coupling in WSe2/hBN heterostructures. Nat. Phys. 13, 127–131 (2017).

    Article  Google Scholar 

  39. Rivera, P. et al. Valley-polarized exciton dynamics in a 2D semiconductor heterostructure. Science 351, 688–691 (2016).

    Article  Google Scholar 

  40. Karrai, K. & Grober, R. D. Piezoelectric tip-sample distance control for near field optical microscopes. Appl. Phys. Lett. 66, 1842–1844 (1995).

    Article  Google Scholar 

Download references

Acknowledgements

The authors would like to thank M. D. Lukin for insightful discussions. K.-D.P., T.J. and M.B.R. acknowledge funding from the US Department of Energy, Office of Basic Sciences, Division of Material Sciences and Engineering, under award no. DE-SC0008807. G.C. and X.X. acknowledge support from NSF-EFRI-1433496. We also acknowledge support provided by the Center for Experiments on Quantum Materials (CEQM) of the University of Colorado.

Author information

Authors and Affiliations

Authors

Contributions

M.B.R. and K.-D.P. conceived the experiment. K.-D.P. performed the measurements and the FDTD simulations. K.-D.P. and M.B.R. designed the samples, and G.C. and X.X. prepared the samples. K.-D.P. and M.B.R. analysed the data, and all authors discussed the results. K.-D.P. and M.B.R. wrote the manuscript with contributions from all authors. M.B.R. supervised the project.

Corresponding author

Correspondence to Markus B. Raschke.

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

41565_2017_3_MOESM1_ESM.pdf

Supplementary Information to:Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Park, KD., Jiang, T., Clark, G. et al. Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect. Nature Nanotech 13, 59–64 (2018). https://doi.org/10.1038/s41565-017-0003-0

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41565-017-0003-0

This article is cited by

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