Nanotribology and Nanofabrication of MoO 3 Structures by Atomic Force Microscopy

Abstract

Atomic force microscopy was used to characterize the sliding of molybdenum oxide (MoO ₃ ) nanocrystals on single-crystal molybdenum disulfide (MoS ₂ ) surfaces. Highly anisotropic friction was observed whereby MoO ₃ nanocrystals moved only along specific directions of the MoS ₂ surface lattice. The energy per unit area to move the MoO ₃ nanocrystals along their preferred sliding direction was an order of magnitude less than required to slide macroscopic MoS ₂ -bearing contacts. This extreme friction anisotropy was exploited to fabricate multicomponent MoO ₃ nanostructures. These reversibly interlocking structures could serve as the basis for devices such as mechanical logic gates.