Lee Hyunsoo, Lee Naesung, Seo Yongho, Eom Jonghwa, Lee SangWook
Faculty of Nanotechnology and Advanced Material Engineering and Institute of Fundamental Physics, Sejong University, Seoul 143-747, Korea.
Nanotechnology. 2009 Aug 12;20(32):325701. doi: 10.1088/0957-4484/20/32/325701. Epub 2009 Jul 21.
We report on the frictional force between an SiN tip and graphene/graphite surfaces using lateral force microscopy. The cantilever we have used was made of an SiN membrane and has a low stiffness of 0.006 N m(-1). We prepared graphene flakes on a Si wafer covered with silicon oxides. The frictional force on graphene was smaller than that on the Si oxide and larger than that on graphite (multilayer of graphene). Force spectroscopy was also employed to study the van der Waals force between the graphene and the tip. Judging that the van der Waals force was also in graphite-graphene-silicon oxide order, the friction is suspected to be related to the van der Waals interactions. As the normal force acting on the surface was much weaker than the attractive force, such as the van der Waals force, the friction was independent of the normal force strength. The velocity dependency of the friction showed a logarithmic behavior which was attributed to the thermally activated stick-slip effect.
我们使用横向力显微镜报告了氮化硅尖端与石墨烯/石墨表面之间的摩擦力。我们使用的悬臂由氮化硅膜制成，刚度较低，为0.006 N m(-1)。我们在覆盖有氧化硅的硅片上制备了石墨烯薄片。石墨烯上的摩擦力小于氧化硅上的摩擦力，大于石墨（多层石墨烯）上的摩擦力。还采用力谱法研究了石墨烯与尖端之间的范德华力。鉴于范德华力也按石墨-石墨烯-氧化硅的顺序排列，推测摩擦力与范德华相互作用有关。由于作用在表面上的法向力远弱于诸如范德华力等吸引力，摩擦力与法向力强度无关。摩擦力的速度依赖性呈现对数行为，这归因于热激活的粘滑效应。
