Exciton tuning in monolayer WSe2 via substrate induced electron doping

Yang Pan, Mahfujur Rahaman, Lu He, Ilya Milekhin, Gopinath Manoharan, Muhammad Awais Aslam, Thomas Blaudeck, Andreas Willert, Aleksandar Matkovic, Teresa I. Madeira, Dietrich R.T. Zahn

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

We report large exciton tuning in WSe2 monolayers via substrate induced non-degenerate doping. We observe a redshift of ∼62 meV for the A exciton together with a 1–2 orders of magnitude photoluminescence (PL) quenching when the monolayer WSe2 is brought in contact with highly oriented pyrolytic graphite (HOPG) compared to dielectric substrates such as hBN and SiO2. As the evidence of doping from HOPG to WSe2, a drastic increase of the intensity ratio of trions to neutral excitons was observed. Using a systematic PL and Kelvin probe force microscopy (KPFM) investigation on WSe2/ HOPG, WSe2/hBN, and WSe2/graphene, we conclude that this unique excitonic behavior is induced by
electron doping from the substrate. Our results propose a simple yet efficient way for exciton tuning in monolayer WSe2, which plays a central role in the fundamental understanding and further device development.
OriginalspracheEnglisch
Seitenumfang7
FachzeitschriftNanoscale advances
Jahrgang2022
Ausgabenummer23
DOIs
PublikationsstatusElektronische Veröffentlichung vor Drucklegung. - 25 Okt. 2022

Bibliographische Notiz

Funding Information:
The authors gratefully acknowledge financial support by the Deutsche Forschungsgemeinschaft (DFG, projects ZA 146/43-1 and ZA 146/47-1). M. A. A. and A. M. acknowledge financial support by the Austrian Science Fund (FWF) under the grant no. I4323-N36. We thank Manuel Monecke for helping with the UPS measurement.

Publisher Copyright:
© The Royal Society of Chemistry 2022.

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