Description
As a two-dimensional material, monolayer MoS2 possesses very unique and promising mechanical and electrical properties. However, the role of point and line defects on mechanical behavior has not been explored. In this study, molecular dynamics simulations using a reactive empirical bond order potential are performed (i) to gain insight into the failure mechanism of monolayer MoS2 by modeling nano-indentation on a suspended free-standing membrane, analogous to recent experiments, and (ii) to explore the influence of point and line defects on the mechanical properties of monolayer MoS2. Results show that the force required for fracture of the monolayer MoS2 membrane increases with increasing nanoindenter diameter. This relationship and the magnitudes of the breaking forces computed in this study are consistent with experiments in the literature. A phase transformation, caused by an abrupt change in the S–S intralayer spacing, is observed prior to failure. For monolayer MoS2 with point defects, the phase transformation initiates from clusters of neighboring point vacancies. For monolayer MoS2 with grain boundaries, molecular dynamics simulations indicate that the fracture strength is independent of the grain boundary energy.
Recommended Citation
Dang, K., & Spearot, D. (2014). Mechanical behavior of monolayer molybdenum disulphide (MoS2) with point defects and grain boundaries. In A. Bajaj, P. Zavattieri, M. Koslowski, & T. Siegmund (Eds.). Proceedings of the Society of Engineering Science 51st Annual Technical Meeting, October 1-3, 2014 , West Lafayette: Purdue University Libraries Scholarly Publishing Services, 2014. https://docs.lib.purdue.edu/ses2014/mss/mmemb/17
Mechanical behavior of monolayer molybdenum disulphide (MoS2) with point defects and grain boundaries
As a two-dimensional material, monolayer MoS2 possesses very unique and promising mechanical and electrical properties. However, the role of point and line defects on mechanical behavior has not been explored. In this study, molecular dynamics simulations using a reactive empirical bond order potential are performed (i) to gain insight into the failure mechanism of monolayer MoS2 by modeling nano-indentation on a suspended free-standing membrane, analogous to recent experiments, and (ii) to explore the influence of point and line defects on the mechanical properties of monolayer MoS2. Results show that the force required for fracture of the monolayer MoS2 membrane increases with increasing nanoindenter diameter. This relationship and the magnitudes of the breaking forces computed in this study are consistent with experiments in the literature. A phase transformation, caused by an abrupt change in the S–S intralayer spacing, is observed prior to failure. For monolayer MoS2 with point defects, the phase transformation initiates from clusters of neighboring point vacancies. For monolayer MoS2 with grain boundaries, molecular dynamics simulations indicate that the fracture strength is independent of the grain boundary energy.