scroll to top
0

Mobile Menu

Header Layout

EBSCO Auth Banner

Let's find your institution. Click here.

Page title

Upconversion of Light into Bright Intravalley Excitons via Dark Intervalley Excitons in hBN-Encapsulated WSe 2 Monolayers.

  • Academic Journal
  • Jadczak J; Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
    Glazov M; Ioffe Institute, 194021 St. Petersburg, Russia.
    Kutrowska-Girzycka J; Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
    Schindler JJ; Experimental Physics 2, TU Dortmund University, 44227 Dortmund, Germany.
    Debus J; Experimental Physics 2, TU Dortmund University, 44227 Dortmund, Germany.
    Ho CH; Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
    Watanabe K; National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
    Taniguchi T; National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan.
    Bayer M; Experimental Physics 2, TU Dortmund University, 44227 Dortmund, Germany.
    Bryja L; Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
  • ACS nano [ACS Nano] 2021 Dec 28; Vol. 15 (12), pp. 19165-19174. Date of Electronic Publication: 2021 Nov 04.
  • English
  • Semiconducting monolayers of transition-metal dichalcogenides are outstanding platforms to study both electronic and phononic interactions as well as intra- and intervalley excitons and trions. These excitonic complexes are optically either active (bright) or inactive (dark) due to selection rules from spin or momentum conservation. Exploring ways of brightening dark excitons and trions has strongly been pursued in semiconductor physics. Here, we report on a mechanism in which a dark intervalley exciton upconverts light into a bright intravalley exciton in hBN-encapsulated WSe 2 monolayers. Excitation spectra of upconverted photoluminescence reveals resonances at energies 34.5 and 46.0 meV below the neutral exciton in the nominal WSe 2 transparency range. The required energy gains are theoretically explained by cooling of resident electrons or by exciton scattering with Λ- or K -valley phonons. Accordingly, an elevated temperature and a moderate concentration of resident electrons are necessary for observing the upconversion resonances. The interaction process observed between the inter- and intravalley excitons elucidates the importance of dark excitons for the optics of two-dimensional materials.
Additional Information
Publisher: American Chemical Society Country of Publication: United States NLM ID: 101313589 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1936-086X (Electronic) Linking ISSN: 19360851 NLM ISO Abbreviation: ACS Nano Subsets: PubMed not MEDLINE; MEDLINE
Original Publication: Washington D.C. : American Chemical Society
Nano Lett. 2019 Apr 10;19(4):2299-2312. (PMID: 30860847)
Nat Commun. 2019 Jan 10;10(1):107. (PMID: 30631049)
Materials (Basel). 2021 Jan 15;14(2):. (PMID: 33467435)
Nat Commun. 2021 Jan 22;12(1):538. (PMID: 33483475)
Science. 2018 Feb 2;359(6375):579-582. (PMID: 29420291)
Nanotechnology. 2017 Sep 27;28(39):395702. (PMID: 28832017)
Nat Commun. 2020 Jan 30;11(1):618. (PMID: 32001715)
Nat Commun. 2015 Apr 02;6:6736. (PMID: 25832503)
Nat Commun. 2018 Sep 13;9(1):3718. (PMID: 30214026)
Sci Rep. 2017 Apr 06;7:45998. (PMID: 28382955)
Phys Rev Lett. 2019 May 31;122(21):217401. (PMID: 31283327)
ACS Nano. 2017 Nov 28;11(11):11162-11168. (PMID: 29088529)
Nano Lett. 2020 Apr 8;20(4):2849-2856. (PMID: 32084315)
Phys Rev Lett. 2017 Jul 28;119(4):047401. (PMID: 29341750)
Nat Commun. 2018 Sep 13;9(1):3717. (PMID: 30214001)
Phys Rev Lett. 2012 May 11;108(19):196802. (PMID: 23003071)
Nat Commun. 2017 Apr 03;8:14927. (PMID: 28367962)
Nanotechnology. 2014 Sep 19;25(37):375703. (PMID: 25158867)
Nanotechnology. 2018 Aug 10;29(32):325705. (PMID: 29781447)
Science. 2020 Dec 4;370(6521):1199-1204. (PMID: 33273099)
Phys Rev Lett. 2020 May 15;124(19):196802. (PMID: 32469553)
Phys Rev Lett. 2019 Aug 30;123(9):096803. (PMID: 31524465)
Nat Commun. 2019 Jun 6;10(1):2469. (PMID: 31171789)
Nanotechnology. 2021 Jan 19;32(14):145717. (PMID: 33463532)
Nanotechnology. 2019 Jun 14;30(24):245708. (PMID: 30836333)
Phys Rev Lett. 2019 Jul 12;123(2):027401. (PMID: 31386514)
Phys Rev Lett. 2010 Sep 24;105(13):136805. (PMID: 21230799)
Nat Commun. 2016 Sep 02;7:12715. (PMID: 27586517)
Keywords: WSe2 monolayer; electron−electron interaction; electron−phonon interaction; inter- and intravalley excitons; photoluminescence; upconversion
Date Created: 20211104 Latest Revision: 20211231
20220908
PMC8717626
10.1021/acsnano.1c08286
34735768

banner_970x250 (970x250)

sponsored