Anisotropic nanofriction on MoS2 with different thicknesses
Anisotropic nanofriction on MoS2 with different thicknesses
复制标题
不同厚度MoS2上的各向异性纳米摩擦
DOI：
10.1016/j.triboint.2019.02.010
复制
发表时间：
2019-06-01
影响因子：
6.2
通讯作者：
Yi, Wangmin
中科院分区：
文献类型：
--
作者：
Cao, Xing'an;Gan, Xuehui;Yi, Wangmin
二硫化钼（MoS2）上的纳米摩擦对于微纳机电系统（MEMS/NEMS）的长期稳定性和可靠性起着至关重要的作用。通过环境空气中校准的原子力显微镜 (AFM) 研究了 MoS2 上的各向异性纳米摩擦力与厚度的函数关系。厚度为 45.23 nm 的 MoS2 上的纳米摩擦力呈现出 180 度的周期性，与锯齿型晶格取向的相同周期性相关。采用二维 Prandtl-Tomlinson 模型来解释厚度为 45.23 nm 的 MoS2 上的各向异性纳米摩擦，即沿扶手椅晶格取向的较长移动长度相对于锯齿晶格取向耗散更多的能量。在厚度为 4.18 nm 的 MoS2 上观察到的各向异性纳米摩擦归因于晶格取向和起皱效应的结合。厚度为1.49 nm的MoS2上的各向异性纳米摩擦主要是由于起皱效应在纳米摩擦中占主导地位。随着MoS2厚度的增加，纳米摩擦的大小减小，纳米摩擦的各向异性比增加。结构各向异性与厚度的耦合在MoS2 上的各向异性纳米摩擦中起着重要作用。这项研究可以为MoS2和其他二维材料在润滑应用中的设计提供线索。
The nanofriction on molybdenum disulfide (MoS2) plays a crucial role in the long-term stability and reliability of micro- and nano-electromechanical systems (MEMS/NEMS). The anisotropic nanofriction force on MoS2 as a function of thickness was studied by a calibrated atomic force microscopy (AFM) in ambient air. The nano friction force on MoS2 with a thickness of 45.23 nm presents a periodicity of 180 degrees correlating to the same periodicity of the sawtooth-type lattice orientation. The two-dimensional Prandtl-Tomlinson model that the longer moving length along the armchair lattice orientation dissipated more energy with respect to zigzag lattice orientation was adopted in interpreting the anisotropic nanofriction on MoS2 with a thickness of 45.23 nm. The observed anisotropic nanofriction on MoS2 with a thickness of 4.18 nm was attributed to the combination of the lattice orientation and puckering effect. The anisotropic nanofriction on MoS2 with a thickness of 1.49 nm was mainly due to the puckering effect dominating the nanofriction. As the thickness of MoS2 increased, the magnitude of nanofriction decreased, and the anisotropy ratio of nanofriction increased. The structural anisotropy coupling with thickness play an important role in the anisotropic nanofriction on MoS2. This study could provide the clue for the design of MoS2 and other two-dimensional materials in lubrication applications.