Excitonic linewidth and coherence lifetime in monolayer transition metal dichalcogenides

Abstract

Atomically thin transition metal dichalcogenides are direct-gap semiconductors with strong light–matter and Coulomb interactions. The latter accounts for tightly bound excitons, which dominate their optical properties. Besides the optically accessible bright excitons, these systems exhibit a variety of dark excitonic states. They are not visible in the optical spectra, but can strongly influence the coherence lifetime and the linewidth of the emission from bright exciton states. Here, we investigate the microscopic origin of the excitonic coherence lifetime in two representative materials (WS 2 and MoSe 2 ) through a study combining microscopic theory with spectroscopic measurements. We show that the excitonic coherence lifetime is determined by phonon-induced intravalley scattering and intervalley scattering into dark excitonic states. In particular, in WS 2 , we identify exciton relaxation processes involving phonon emission into lower-lying dark states that are operative at all temperatures.

Full text

Its licence does not allow us to show the full text. Read it at PubMed Central:

References 42

1. 1.

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

   Not in our library10.1103/physrevlett.113.026803

2. 2.

   Chernikov A.. Exciton binding energy and nonhydrogenic rydberg series in monolayer WS2. Phys. Rev. Lett. 113, 076802 (2014 ).

   Not in our library10.1103/physrevlett.113.076802

3. 3.

   Berghäuser G. & Malic E. Analytical approach to excitonic properties of MoS2. Phys. Rev. B 89, 125309 (2014 ).

   Not in our library

4. 4.

   Ramasubramaniam A. Large excitonic effects in monolayers of molybdenum and tungsten dichalcogenides. Phys. Rev. B 86, 115409 (2012 ).

   Not in our library

5. 5.

   Tonndorf P.. Photoluminescence emission and Raman response of monolayer MoS2, MoSe2, and WSe2. Opt. Express 21, 4908–4916 (2013 ).

   Not in our library10.1364/oe.21.004908

6. 6.

   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 ).

   Not in our library10.1103/physrevlett.105.136805

7. 7.

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

   Not in our library10.1021/nl903868w

8. 8.

   Radisavljevic B., Radenovic A., Brivio J., Giacometti V. & Kis A. Single-layer MoS2 transistors. Nat. Nano 6, 147–150 (2011 ).

   Not in our library10.1038/nnano.2010.279

9. 9.

   Lee C.. Anomalous lattice vibrations of single- and few-layer MoS2. ACS Nano 4, 2695–2700 (2010 ).

   Not in our library10.1021/nn1003937

10. 10.

    Schmidt R.. A ultrafast Coulomb-induced intervalley coupling in atomically thin WS2. Nano Lett. 16, 2945–2950 (2016 ).

    Not in our library10.1021/acs.nanolett.5b04733

11. 11.

    Qiu D. Y., Cao T. & Louie S. G. Nonanalyticity, valley quantum phases, and lightlike exciton dispersion in monolayer transition metal dichalcogenides: theory and first-principles calculations. Phys. Rev. Lett. 115, 176801 (2015 ).

    Not in our library10.1103/physrevlett.115.176801

12. 12.

    Wu F., Qu F. & MacDonald A. H. Exciton band structure of monolayer MoS2. Phys. Rev. B 91, 075310 (2015 ).

    Not in our library

13. 13.

    Steinhoff A.. Efficient excitonic photoluminescence in direct and indirect band gap monolayer MoS2. Nano Lett. 15, 6841–6847 (2015 ).

    Not in our library10.1021/acs.nanolett.5b02719

14. 14.

    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 ).

    Not in our library10.1103/physrevlett.115.257403

15. 15.

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

    Not in our library10.1039/c5nr01536g

16. 16.

    Kira M. & Koch S. Many-body correlations and excitonic effects in semiconductor spectroscopy. Prog. Quantum Electron. 30, 155–296 (2006 ).

    Not in our library

17. 17.
    Intrinsic homogeneous linewidth and broadening mechanisms of excitons in monolayer transition metal dichalcogenides · 2015

    No notice
18. 18.

    Dey P.. Optical coherence in atomic-monolayer transition-metal dichalcogenides limited by electron–phonon interactions. Phys. Rev. Lett. 116, 127402 (2016 ).

    Not in our library10.1103/physrevlett.116.127402

19. 19.

    Arora A.. Exciton band structure in layered MoSe2: from a monolayer to the bulk limit. Nanoscale 7, 20769–20775 (2015 ).

    Not in our library10.1039/c5nr06782k

20. 20.

    Koirala S., Mouri S., Miyauchi Y. & Matsuda K. Homogeneous linewidth broadening and exciton dephasing mechanism in MoTe2. Phys. Rev. B 93, 075411 (2016 ).

    Not in our library

21. 21.

    Glazov M. M.. Exciton fine structure and spin decoherence in monolayers of transition metal dichalcogenides. Phys. Rev. B 89, 201302 (2014 ).

    Not in our library

22. 22.

    Song Y. & Dery H. Transport theory of monolayer transition-metal dichalcogenides through symmetry. Phys. Rev. Lett. 111, 026601 (2013 ).

    Not in our library10.1103/physrevlett.111.026601

23. 23.

    Poellmann C.. Resonant internal quantum transitions and femtosecond radiative decay of excitons in monolayer WSe2. Nat. Mater. 14, 889–893 (2015 ).

    Not in our library10.1038/nmat4356

24. 24.

    Axt V. M. & Kuhn T. Femtosecond spectroscopy in semiconductors: a key to coherences, correlations and quantum kinetics. Rep. Prog. Phys. 67, 433 (2004 ).

    Not in our library

25. 25.

    Haug H. & Koch S. W. Quantum Theory of the Optical and Electronic Properties of Semiconductors 5th edn World Scientific Publishing Co. Pre. Ltd. (2004 ).

    Not in our library

26. 26.

    Cudazzo P., Tokatly I. V. & Rubio A. Dielectric screening in two-dimensional insulators: implications for excitonic and impurity states in graphane. Phys. Rev. B 84, 085406 (2011 ).

    Not in our library

27. 27.

    Thränhardt A., Kuckenburg S., Knorr A., Meier T. & Koch S. W. Quantum theory of phonon-assisted exciton formation and luminescence in semiconductor quantum wells. Phys. Rev. B 62, 2706–2720 (2000 ).

    Not in our library

28. 28.

    Malic E. & Knorr A. Graphene and Carbon Nanotubes: Ultrafast Optics and Relaxation Dynamics 1st edn Wiley-VCH (2013 ).

    Not in our library

29. 29.

    Zeng H., Dai J., Yao W., Xiao D. & Cui X. Valley polarization in MoS2 monolayers by optical pumping. Nat. Nano 7, 490–493 (2012 ).

    Not in our library10.1038/nnano.2012.95

30. 30.

    Cao T.. Valley-selective circular dichroism of monolayer molybdenum disulphide. Nat. Commun. 3, 887 (2012 ).

    Not in our library10.1038/ncomms1882

31. 31.

    Xu X., Yao W., Xiao D. & Heinz T. F. Spin and pseudospins in layered transition metal dichalcogenides. Nat. Phys. 10, 343–350 (2014 ).

    Not in our library

32. 32.

    Li X.. Intrinsic electrical transport properties of monolayer silicene and MoS2 from first principles. Phys. Rev. B 87, 115418 (2013 ).

    Not in our library

33. 33.

    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 ).

    Not in our library

34. 34.

    Schilp J., Kuhn T. & Mahler G. Electron-phonon quantum kinetics in pulse-excited semiconductors: memory and renormalization effects. Phys. Rev. B 50, 5435–5447 (1994 ).

    Not in our library10.1103/physrevb.50.5435

35. 35.

    Haug H. & Jauho A.-P. Quantum Kinetics in Transport and Optics of Semiconductors 2nd edn Springer-Verlag (2008 ).

    Not in our library

36. 36.

    Knorr A., Hughes S., Stroucken T. & Koch S. Theory of ultrafast spatio-temporal dynamics in semiconductor heterostructures. Chem. Phys. 210, 27–47 (1996 ).

    Not in our library

37. 37.

    Wang H.. Radiative lifetimes of excitons and trions in monolayers of the metal dichalcogenide MoS2. Phys. Rev. B 93, 045407 (2016 ).

    Not in our library

38. 38.

    Zhao W.. Origin of indirect optical transitions in few-layer MoS2, WS2, and WSe2. Nano Lett. 13, 5627–5634 (2013 ).

    Not in our library10.1021/nl403270k

39. 39.

    Kormányos A.. k⋅p theory for two-dimensional transition metal dichalcogenide semiconductors. 2D Mater. 2, 022001 (2015 ).

    Not in our library

40. 40.

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

    Not in our library

41. 41.

    Ivchenko E. L.. Optical spectroscopy of semiconductor nanostructures. Alpha Science Int'l Ltd.. (2015 ).

    Not in our library

42. 42.

    Olivero J. & Longbothum R. Empirical fits to the voigt line width: a brief review. J. Quant. Spectrosc. Radiat. Transf. 17, 233–236 (1977 ).

    Not in our library

Cited by papers we hold 3

• Photonic-crystal exciton-polaritons in monolayer semiconductors · 2018
  No notice
• Two-dimensional semiconductors in the regime of strong light-matter coupling · 2018
  No notice
• Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature · 2017
  No notice

Reads

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.