Temperature dependent interlayer exciton diffusion in a WSe<sub>2</sub>/WS<sub>2</sub> moiré superlattice

ORAL

Abstract

The moiré potential arising from the relative twist and lattice mismatch in heterobilayers of two-dimensional materials has led to the discovery of novel excitonic species. Twist-angle dependent transport measurements of these interlayer excitons have been reported for WSe2/WS2 heterobilayers [1]. In our experiment, we use time- and spatially resolved spectroscopies to investigate the temperature dependent lifetime and diffusion length of various interlayer excitons in WSe2/WS2 heterobilayers, where the individual monolayers have been aligned to produce long-range moiré superlattices. We observe that the interlayer exciton diffusion length increases with temperature till it undergoes a phonon-driven transition where the intralayer exciton starts to dominate the photoluminescence spectrum. The temperature dependent formation of the interlayer exciton is reflected in the overall lifetime and diffusion lengths of exciton species in the WSe2/WS2 heterobilayer.

 

[1] Yuan, Long, et al. Nature materials 19.6 (2020): 617-623

*A.R. acknowledge funding from The Molecular Foundry and Center for Novel Pathways to Quantum Coherence in MaterialsJ.Z and A.R acknowledge Early Career LDRD Program of Lawrence Berkeley National Laboratory under DOE Contract No. DE-AC02-05CH11231Work at the Molecular Foundry was supported by the DOE Office of Basic Energy Sciences under Contract No. DE-AC02-05CH11231.

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Presenters

  • Antonio Rossi

    • Lawrence Berkeley National Laboratory

Authors

  • Antonio Rossi

    • Lawrence Berkeley National Laboratory

  • Jonas Zipfel

    • Lawrence Berkeley National Laboratory
    • Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, USA

  • Emma Regan

    • University of California, Berkeley

  • Daria Blach

    • Purdue University
    • Department of Chemistry, Purdue University

  • Luca Francaviglia

    • Lawrence Berkeley National Laboratory

  • Monica Lorenzon

    • Lawrence Berkeley National Laboratory

  • Edward S Barnard

    • Lawrence Berkeley National Laboratory
    • LBNL
    • Berkeley Lab

  • Eli Rotenberg

    • Lawrence Berkeley National Laboratory

  • feng wang

    • University of California, Berkeley

  • Archana Raja

    • Lawrence Berkeley National Laboratory

  • Alexander Weber-Bargioni

    • Lawrence Berkeley National Laboratory
    • LBNL