Force microscopy of two-dimensional materials

AFM;Two-dimensional materials;van der Waals force;Elasticity

Gao, Yang ; Riedo, Elisa Physics First, Phillip Davidovic, Dragomir Jiang, Zhigang Degertekin, Levent ; Riedo, Elisa

University:Georgia Institute of Technology

Department:Physics

关键词: AFM;    Two-dimensional materials;    van der Waals force;    Elasticity;   

Others  :  https://smartech.gatech.edu/bitstream/1853/59799/1/GAO-DISSERTATION-2017.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

Atomic Force Microscopy (AFM) is a powerful tool for the characterization and fabrication of two-dimensional materials, which are films of a few atomic layers with strong in-plane bonds and weak van der Waals interactions between the layers. The in-plane elasticity has been widely studied with nano-indentation where a suspended 2D film is bent substantially (~10nm to 1000nm). In this thesis we report on a novel AFM-based sub-Å-resolution indentation technique: Modulated nano-indentation (MoNI) or "Å-indentation". MoNI can allow for indentation below 1 Å, smaller than the inter-layer distance of most 2D materials. The perpendicular-to-the-plane elasticity of 2D materials can be detected with MoNI at extremely high precision while the in-plane covalent bonds are negligible. The inter-layer elasticity as well as intercalation properties of epitaxial graphene, graphene oxide and other 2D materials were carefully investigated. Furthermore, the fingerprint of a new ultra-hard phase of epitaxial graphene on SiC(0001), indicating possible diamondization at room temperature, has been observed and reported in this thesis.