Nanoscale friction of strained molybdenum disulfide induced by nanoblisters

Abstract

Nanoblisters have received substantial attention owing to their ability to controllably modulate physical properties of two-dimensional (2D) layered materials. Herein, we demonstrated that nanoblisters formed by molybdenum disulfide (MoS2) can produce in-plane strains via out-of-plane deformation. The in-plane strains can effectively modulate frictional behaviors of MoS2. Friction force microscopy results showed that the friction was significantly increased at the edge of MoS2 nanoblisters due to the "step edge effect."In addition, the friction measured in the central area of the MoS2 nanoblisters was found increased as the height to radius aspect ratios of MoS2 nanoblisters increased. Our atomically resolved friction images revealed that the dynamic friction tuned via nanoblisters was originated from the changes in the movement state of the tip caused by the in-plane strains. This study clarified the feasibility of nanoblisters as a simple strain engineering strategy to modulate the friction properties of 2D materials.