Journal Article

FZJ-2020-02148

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Unveiling Valley Lifetimes of Free Charge Carriers in Monolayer WSe 2

Ersfeld, M.RWTH* ; Volmer, F.RWTH* ; Rathmann, L.RWTH* ; Kotewitz, L.RWTH* ; Heithoff, M.RWTH* ; Lohmann, M. ; Yang, B. ; Watanabe, K. ; Taniguchi, T. ; Bartels, L. ; Shi, J. ; Stampfer, C.FZJ* ; Beschoten, B. (Corresponding author)FZJ*

2020
ACS Publ. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/24935  doi:10.1021/acs.nanolett.9b05138

Abstract: We report on nanosecond-long, gate-dependent valley lifetimes of free charge carriers in monolayer WSe2, unambiguously identified by the combination of time-resolved Kerr rotation and electrical transport measurements. While the valley polarization increases when tuning the Fermi level into the conduction or valence band, there is a strong decrease of the respective valley lifetime consistent with both electron-phonon and spin-orbit scattering. The longest lifetimes are seen for spin-polarized bound excitons in the band gap region. We explain our findings via two distinct, Fermi-level-dependent scattering channels of optically excited, valley-polarized bright trions either via dark or bound states. By electrostatic gating we demonstrate that the transition-metal dichalcogenide WSe2 can be tuned to be either an ideal host for long-lived localized spin states or allow for nanosecond valley lifetimes of free charge carriers (>10 ns).

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Contributing Institute(s):

1. Halbleiter-Nanoelektronik (PGI-9)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 521 - Controlling Electron Charge-Based Phenomena (POF3-521) (POF3-521)

Appears in the scientific report 2020

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 10 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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