Effect of Oxygen Plasma Treatment on the Structure and Mechanical Properties of Bilayer Graphene Studied by Molecular Dynamics Simulation
JC Chen and JY Pei and HY Zhao, JOURNAL OF PHYSICAL CHEMISTRY C, 125, 19345-19352 (2021).
Bilayer graphene (BG) may achieve better optoelectronic and sensing applications after modification due to its direct induced band gap and better plasma processing stability. Defect engineering based on oxygen plasma treatment has been proved to be an effective method to achieve the modification of graphene. Understanding the formation and evolution of graphene defects, which cannot be observed directly by the experiment, can help achieve more precise and controllable modification of graphene. Here, we investigate the effect of oxygen plasma treatment on the structure and mechanical properties of BG by molecular dynamics simulations. We report two mechanisms of BG destruction by oxygen plasma: direct sputtering and cascade sputtering. When the defects are mainly sp(3) defects, we report that the elastic modulus is strongly related to oxygen density, and it decreases by only about 16% at low oxygen density (3.92 x 10(21) atoms(center dot) cm(-3)). In contrast, the mechanical properties of BG decrease more significantly when vacancy defects are predominant. Based on the formation and evolution of sp3 defects and vacancy defects, we establish the relationship between defect types and the mechanical properties of BG. This study makes it possible to precisely control the graphene structure for optoelectronic and sensing applications.
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