Strong Second Harmonic Generation from Bilayer Graphene with Symmetry Breaking by Redox-Governed Charge Doping

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2022-05-24
Major/Subject
Mcode
Degree programme
Language
en
Pages
7
4287-4293
Series
Nano Letters, Volume 22, issue 11
Abstract
Missing second-order nonlinearity in centrosymmetric graphene overshadows its intriguing optical attribute. Here, we report redox-governed charge doping could effectively break the centrosymmetry of bilayer graphene (BLG), enabling a strong second harmonic generation (SHG) with a strength close to that of the well-known monolayer MoS2. Verified from control experiments with in situ electrical current annealing and electrically gate-controlled SHG, the required centrosymmetry breaking of the emerging SHG arises from the charge-doping on the bottom layer of BLG by the oxygen/water redox couple. Our results not only reveal that charge doping is an effective way to break the inversion symmetry of BLG despite its strong interlayer coupling but also indicate that SHG spectroscopy is a valid technique to probe molecular doping on two-dimensional materials.
Description
Funding Information: This work is supported by the National Key R&D Program of China (Grants 2018YFA0307200 and 2017YFA0303800), the National Natural Science Foundation of China (Grants 61775183, 11634010, and 61905196), the Key R&D Program of Shaanxi Province (Grant 2020JZ-10), Key R&D Program of Guangdong Province (Grants 2020B010189001, 2019B010931001, and 2018B030327001), and the Fundamental Research Funds for the Central Universities (Grants 3102017jc01001, 3102019JC008, and 310201911cx032). Publisher Copyright: © 2022 American Chemical Society.
Keywords
bilayer graphene, charge transfer, oxygen reduction reaction, second harmonic generation, symmetry breaking
Other note
Citation
Zhang , M , Han , N , Wang , J , Zhang , Z , Liu , K , Sun , Z , Zhao , J & Gan , X 2022 , ' Strong Second Harmonic Generation from Bilayer Graphene with Symmetry Breaking by Redox-Governed Charge Doping ' , Nano Letters , vol. 22 , no. 11 , pp. 4287-4293 . https://doi.org/10.1021/acs.nanolett.1c04359