Effects of surface defects on mechanical properties and fracture mechanism of gallium selenide/graphene heterostructure

Abstract

Nowadays, stacking of two-dimension (2D) van der Waals (vdW) heterostructures (Hs) to obtain hybrid structures, like Gallium selenide (GaSe) and graphene (Gr), provides more opportunities and suitable systems for designing optoelectronic devices. Therefore, we created 2D GaSe/Graphene heterostructures (GaSeGrHs) with various defect lines designed to survey its mechanical properties with tunable parameters using molecular dynamics (MD) simulations. We began with the model validation and continued with the effects of defect length, defect angle, offset line from the center, and parallel defect on the mechanical properties of GaSeGrHs. Hence, defect engineering was used to adjust the GaSeGrHs membrane anisotropic belongings. We found that Young's modulus, failure stress, and strain of the GaSeGr heterostructure are much higher than those of pristine GaSe due to the graphene substrate enhancement, with ∼5.8/1.2/5.9 times. The diagram for stress-ratio versus strain-ratio depicts the visualizing and rationalizing of the changing mechanical anisotropy of the GaSeGrHs with line defects. The line-defect designs reveal a high ability and versatility in fine-tuning the mechanical properties of GaSeGrHs in different directions. A systematic comparison between this study and the others is presented. That demonstrates the potential of fine-tuning and improving the 2D materials' mechanical properties for their potential applications in stretchable electronics and supercapacitor devices.