Tensile Mechanical Properties and Edge Defect-Driven Degradation in Bilayer Graphene

Bilayer graphene attracts significant attention due to its unique electronic structure and excellent physical properties, with its mechanical performance being crucial for understanding deformation mechanisms and assessing application reliability. The mechanical properties of bilayer graphene measured by atomic force microscopy currently exhibit considerable scatter and show clear deviations from theoretical predictions. In situ tensile testing is widely regarded as a more reliable and authoritative approach for evaluating the mechanical properties of two-dimensional materials. Accordingly, the Young's modulus of bilayer graphene is measured to be 873.80 ± 12.68 GPa using a push-to-pull device inside a scanning electron microscope, which is close to the theoretical value. Moreover, the integration of bilayer graphene into device architectures requires micro/nanoscale patterning and shaping, which inevitably introduces edge defects. However, it remains experimentally challenging to precisely control the concentration of these edge defects. To address these limitations, a combined approach of molecular dynamics simulations and machine learning was employed to systematically uncover the effects of edge defects on the mechanical behavior of bilayer graphene. This study provides a theoretical foundation for a deeper understanding and optimization of the mechanical behavior of bilayer graphene, thereby laying important groundwork for its application in microelectronic devices.