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

Mingwen Zhang, Nannan Han, Jing Wang, Zhihong Zhang, Kaihui Liu, Zhipei Sun, Jianlin Zhao, Xuetao Gan*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)
35 Downloads (Pure)

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.

Original languageEnglish
Pages (from-to)4287-4293
Number of pages7
JournalNano Letters
Volume22
Issue number11
DOIs
Publication statusPublished - 24 May 2022
MoE publication typeA1 Journal article-refereed

Keywords

  • bilayer graphene
  • charge transfer
  • oxygen reduction reaction
  • second harmonic generation
  • symmetry breaking

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