High Frictional Resilience of MoS₂ Nanosheets to Induced Atomic Vacancies: Implications for Nanoelectromechanical Devices

High Resolution Image Download MS PowerPoint Slide Molybdenum disulfide (MoS 2 ) exhibits exceptional mechanical and wear properties combined with thermal stability, which makes it an outstanding solid lubricant. While numerous studies have reported on the tribological behavior of few-layer pristine MoS 2, little attention has been given to the impact of defects, such as sulfur vacancies, which are inevitable during large-scale fabrications. Understanding the factors that affect friction at the atomic level is essential for the design and optimization of high-performance materials. Here, we present a systematic study of the tribology of one- and two-layer MoS 2 nanosheets, with controllably introduced atomic vacancies, performed by atomic force microscopy. We find that the friction coefficient of mono- and bilayer MoS 2 suffers more than a 3-fold increase from the as-prepared layer (with an initial defect density of 1 × 10 12 cm –2 ) to those with an induced atomic defect density of 1.2 × 10 13 cm –2 . Comparison of the results reported here with analogous results in graphene shows that MoS 2 presents an attractive high resilience of the friction coefficient to monatomic defect generation in the atomic defect density range typically obtained by scalable techniques.