Yang Junjie, Xu Xiaoxuan, Liu Lei
School of Mechanical Engineering, Southeast University, Nanjing 211189, People's Republic of China.
Nanotechnology. 2020 Sep 25;31(39):395711. doi: 10.1088/1361-6528/ab978c. Epub 2020 May 28.
MoS films as an excellent solid lubricating film can significantly decrease the friction and adhesion of nanoelectromechanical systems. Atomic layer deposition (ALD) as a surface-controlled method provides a flexible way to apply MoS to complex surfaces. In this work, MoS film deposited by ALD on substrates by a plasma-assisted process is used to study controlled friction. Firstly, layer-controlled MoS films were fabricated by ALD from one to five layers. The friction decreases as the number of layers increases. Furthermore, the average friction force of MoS deposited on AlO substrates treated by plasma for 10 s with one ALD cycle has the lowest value. Functional groups on the substrate surface can be obtained by plasma treatment, which can control the growth of the first layer of MoS in ALD so that the frictional characteristics of monolayer MoS can be controlled. Finally, the effect of plasma treatment on ALD growth at the intermediate stage of MoS is relatively weak. Only the monolayer MoS treated by plasma can affect the growth of MoS by ALD. Therefore, the controlling effect of plasma treatment on the frictional characteristics of MoS deposited by ALD mainly occurs at the initial stage of growth.
二硫化钼（MoS）薄膜作为一种优异的固体润滑薄膜，能够显著降低纳米机电系统的摩擦力和粘附力。原子层沉积（ALD）作为一种表面控制方法，为将二硫化钼应用于复杂表面提供了一种灵活的方式。在这项工作中，通过等离子体辅助工艺利用ALD在衬底上沉积的二硫化钼薄膜用于研究可控摩擦。首先，通过ALD制备了从一层到五层的层控二硫化钼薄膜。摩擦力随着层数的增加而降低。此外，在经过10秒等离子体处理的氧化铝（AlO）衬底上沉积的、经过一个ALD循环的二硫化钼的平均摩擦力具有最低值。衬底表面的官能团可通过等离子体处理获得，这可以控制ALD中第一层二硫化钼的生长，从而能够控制单层二硫化钼的摩擦特性。最后，等离子体处理对二硫化钼生长中期的ALD的影响相对较弱。只有经过等离子体处理的单层二硫化钼会影响通过ALD生长的二硫化钼。因此，等离子体处理对通过ALD沉积的二硫化钼的摩擦特性的控制作用主要发生在生长的初始阶段。
