Current-Carrying Friction of Atomically Thin Molybdenum Disulfide

Abstract

Understanding the current-carrying nanofriction of molybdenum disulfide (MoS2) is crucial for the development of MoS2-based micro/nanoelectromechanical systems as well as for the application of MoS2 as a solid lubricant in the presence of external electric fields. Herein, the behavior of current-carrying friction in atomically thin MoS2 was explored using conductive atomic force microscopy. The friction force was found increased as the applied voltage increased. Notably, the friction was lower under positive bias voltages compared to positive bias voltages, with the difference in friction becoming more pronounced as the applied voltage increased. Atomically resolved friction imaging together with surface potential mapping revealed that surface charge accumulation on MoS2 significantly impacted its friction behavior, where the electrostatic force created a larger energy barrier for the tip sliding on MoS2 under negative bias voltages in comparison to positive bias voltages. These findings enhance our understanding of the current-carrying friction on atomically thin MoS2 and have important implications for developing next-generation low-friction technologies.

Keywords: friction, molybdenum disulfide, Electric field, conductive atomic force microscopy, friction force microscopy, scanning Kelvin probe microscopy