Exciton tuning in monolayer WSe2via substrate induced electron doping. Issue 23 (1st November 2022)

• Record Type: Journal Article
• Authors: Pan, Yang; Rahaman, Mahfujur; He, Lu; Milekhin, Ilya; Manoharan, Gopinath; Aslam, Muhammad Awais; Blaudeck, Thomas; Willert, Andreas; Matković, Aleksandar; Madeira, Teresa I.; Zahn, Dietrich R. T.
• Is Part Of: Nanoscale advances. Volume 4:Issue 23(2022)
• Page Start: 5102
• Page End: 5108
• Publication Date: 2022-11-01
• Subjects: 620.5
• DOI: 10.1039/d2na00495j
• Languages: English
• ISSNs: 2516-0230

Abstract

Abstract : We report large exciton energy tuning (∼62 meV) in WSe2 monolayers via substrate induced non-degenerate electron doping. 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.