A Comparative Investigation of the Mechanical Properties of Single and Bi Layer MoS2 Structures: Influences of Defect, Strain Rate and Temperature

Abstract

In this paper, the mechanical properties of single and bi layer molybdenum disulfide (MoS2) structures are investigated using uniaxial tensile molecular dynamics (MD) simulation. According to the results of MD simulations, these structures show superior mechanical properties (failure strain, ultimate tensile strength and Young’s modulus) for various applications of nanodevice. The mechanical properties of single and bi layer MoS2 structures are studied at four different temperatures between 300 K and 900 K and different strain rates from 107 s-1 to 109 s-1. As temperature increases up to 900 K, the mechanical properties of single and bi layer MoS2 structures gradually decrease, due to the high temprerature’s weakening effect. Also, changing of temperatures shows more effect on the bi layer MoS2 structure than single layer MoS2 structure. Furthermore, MD results show that the mechanical properties of single and bi layer MoS2 structures demonstrate increasing trend when the strain rate increases. Different strain rates indicate similar effects on the mechanical properties of single and bi layer MoS2 structures. On the other hand, the mechanical properties of these structures are adversely affected by structural defects. Accordingly, the influences of two different S atom types vacancy defect on the mechanical properties of single and bi layer MoS2 structures are examined. When the vacancy defect concentrations in MoS2 structures increase, the mechanical properties of these structures decrease significantly. In addition, S atom bi vacancy defects type exerts more effect on the mechanical properties of single and bi layer MoS2 structures than S atom single vacancy defect type do by increasing concentration. Additionally, vacancy defects indicate more influence on the bi layer MoS2 structure than single layer MoS2 structure. Finally, the results of this study make them excellent candidate for nano-mechanical systems.