Natural overlaying behaviors push the limit of planar cyclic deformation performance in few-layer MoS2 nanosheets

Abstract

<p>As a typical two-dimensional (2D) transition metal dichalcogenides (TMDCs) material with nonzero band gap, MoS2 has a wide range of potential applications as building blocks in the field of nanoelectronics. The stability and reliability of the corresponding nanoelectronic devices depend critically on the mechanical performance and cyclic reliability of 2D MoS2. Although an in situ technique has been used to analyze the mechanical properties of 2D materials, the cyclic mechanical behavior, that is, fatigue, remains a major challenge in the practical application of the devices. This study was aimed at analyzing the planar cyclic performance and deformation behavior of three-layer MoS2 nanosheets (NSs) using an in situ transmission electron microscopy (TEM) variable-amplitude uniaxial low-frequency and cyclic loading-unloading tensile acceleration test. We also elucidated the strengthening effect of the natural overlaying affix fragments (other external NSs) or wrinkle folds (internal folds from the NS itself) on cycling performances and service life of MoS2 NSs by delaying the whole process of fatigue crack initiation, propagation, and fracture. The results have been confirmed by molecular dynamics (MDs) simulations. The overlaying enhancement effect effectively ensures the long-term reliability and stability of nanoelectronic devices made of few-layer 2D materials.</p>