Charge distribution in turbostratic few-layer graphene studied by carbon isotope labeling. (15th April 2022)

• Record Type: Journal Article
• Authors: Zhuang, Pingping; Liu, Jing; Huang, Junjie; Dou, Chao; Cai, Weiwei; Lin, Weiyi
• Is Part Of: Carbon. Volume 189(2022)
• Page Start: 21
• Page End: 26
• Publication Date: 2022-04-15
• Subjects: Isotope-labeling -- Few-layer graphene -- Charge distribution -- Layer-resolved Raman spectroscopy -- Transfer curves; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2021.12.049
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Elucidating layer-resolved charge distribution in van der Waals stacked crystals is crucial for electronic applications based on 2D materials. Here, we use CVD-grown few-layer graphene (FLG) labeled by carbon isotopes as a prototype, in which Raman features of two isotope components identify distinct layers. Electrical transfer characteristics of graphene field-effect transistors (GFETs) are employed to quantitatively calibrate the correspondence of Fermi level and G-phonon frequency that shifts with the charge-carrier concentration ( n ) variation. The isotope-assisted spectroscopy reveals previously unprobed characteristics that the n value of both top and bottom layers in FLG is close rather than following an exponential decay law. This negligible gradient likely benefits from the π − π interaction that favors the interlayer diffusion of charges. In addition, each extra layer reduces the degree of charge exchange at the graphene/dopant interface. These results have important implications for FLG nanoelectronics and provide a robust framework by which one can further investigate the critical properties of other 2D systems. Graphical abstract: Image 1