Atomically thin MoS ₂ with ultra-low friction properties based on strong interface interaction

Atomically thin lubrication materials with anti-friction properties are crucial for reducing energy consumption and extending the service life of micro/nanoelectromechanical systems (MEMS/NEMS). However, achieving atomically thin films with ultra-low friction properties at the atomic/nanoscale even at the micrometer scale presents significant challenges. In this study, large-size and high-quality monolayer MoS₂ (ML MoS₂) was grown on SiO₂/Si substrate by chemical vapor deposition (CVD) method. Compared with mechanically exfoliated ML MoS₂, the CVD-grown ML MoS₂ (CVD-MoS₂) exhibits an ultra-lower friction coefficient (0.00904). Based on the stick-slip effect and Prandtl-Tomlinson model, the reduction of puckering effect indicates stronger interaction and lower interface potential barrier in tip, CVD-MoS₂ and SiO₂/Si substrate system. Moreover, combining with the density functional theory  calculations, the stronger interface adhesion and higher overall charge redistribution degree of CVD-MoS₂ can also be used to explain its ultralow friction state. This work will provide theoretical guidance for designing ultra-thin lubricating materials with ultra-low friction properties.