Improving the atomic-resolution AFM imaging of monolayer MoS2 for worn tips: a molecular dynamics study

In this paper, molecular dynamics simulations were performed to investigate the atomic-scale imaging of a typical two-dimensional monolayer: molybdenum disulfide (MoS2). With a constant height mode, force-displacement curves of tips along a straight-line scanning path indicate resonant waveforms and the periodicities are capable of characterizing lattice parameters of monolayer MoS2. Some characteristic sites in the forcedisplacement curves arise only for tips with a radius of less than 3 A under 1.47 A tip-sample distance, which correlated to the atoms next to the scanning path. Such characteristic sites can be reproduced by using tips with a radius of 7 A via increasing the tip-sample distance. The underlying mechanism was illustrated by the number of interactive atoms between the tip and the sample. The work may shed light on the atomic force microscope (AFM) operation when one expects to achieve high-resolution AFM imaging of 2D materials with a worn AFM tip. (c) 2019 The Japan Society of Applied Physics