Effect of defect on mechanical properties of two-dimensional MoS₂ membranes

Abstract Molybdenum disulfide (MoS 2 ) has wide applications in many fields, such as electrode materials and energy storage. Therefore, it is crucial to investigate and determine how defects affect the mechanical characteristics of 2D MoS 2 membranes. This work examined the impact of vacancy defects on the tensile characteristics of uniaxially and biaxially stressed monolayer MoS 2 using molecular dynamics simulations. We have separated them into different cases, including the impact of the length size and width size of the vacancy defect, defect rotation angle, and vacancy defect’s quantity on the fracture behavior under various tensile loads. The tensile characteristics were examined in both the armchair and zigzag directions. The presence of a vacancy defect causes localized stress concentration, which initiates crack formation at the defect site, resulting in reduced fracture strain. When the size or the number of vacancies increases in the orientation perpendicular to the applied tensile force, it decreases Young’s modulus, ultimate stress, and failure strain of the material. With the same length and width of the defect, altering the angle ( θ ) between the defect edge and the tensile orientation—significantly impacts the material’s mechanical properties. Under uniaxial tension, an increase in the angle θ decreases Young’s modulus, ultimate stress, and failure strain, with the maximum strength occurring at θ = 0°. In contrast, during biaxial tension, the relationship between the mechanical properties and the rotation angle lacks a clear trend, notably, the minimum ultimate stress value is observed when θ = 45°.