Energy Research Institute @ NTU, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore. School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
Nanotechnology. 2017 Sep 1;28(35):355704. doi: 10.1088/1361-6528/aa7a2a. Epub 2017 Jul 31.
Nano-friction of phosphorene plays a significant role in affecting the controllability and efficiency of applying strain engineering to tune its properties. So far, the friction behavior of phosphorene has not been studied. This work studies the friction of single-layer and bilayer phosphorene on an amorphous silicon substrate by sliding a rigid tip. For the single-layer phosphorene, it is found that its friction is highly anisotropic, i.e. the friction is larger along the armchair direction than that along the zigzag direction. Moreover, pre-strain of the phosphorene also exhibits anisotropic effects. The friction increases with the pre-strain along the zigzag direction, but decreases with that along the armchair direction. Furthermore, the strong adhesion between the phosphorene and its substrate increases the friction between the phosphorene and the tip. For bilayer phosphorene, its friction highly depends on its stacking mode, which determines the contact interface with a commensurate or incommensurate pattern. This friction behavior is quite unique and greatly differs from that of graphene and molybdenum disulfide. Detailed analysis reveals that this behavior results from the combination effect of the friction contact area, the potential-energy profile of phosphorene, and its unique elongation.
磷烯的纳米摩擦在影响应变工程可控性和效率方面起着重要作用，从而调控其性能。迄今为止，尚未研究过磷烯的摩擦行为。本工作通过滑动刚性尖端，研究了无定形硅衬底上单层和双层磷烯的摩擦。对于单层磷烯，发现其摩擦具有各向异性，即摩擦在扶手椅方向上大于在锯齿形方向上。此外，磷烯的预应变也表现出各向异性效应。摩擦随沿锯齿形方向的预应变增加而增加，但随沿扶手椅方向的预应变增加而减小。此外，磷烯与其衬底之间的强附着力增加了磷烯与尖端之间的摩擦力。对于双层磷烯，其摩擦高度依赖于其堆叠模式，这决定了与共形或非共形图案的接触界面。这种摩擦行为非常独特，与石墨烯和二硫化钼有很大的不同。详细分析表明，这种行为是摩擦接触面积、磷烯势能曲线以及其独特伸长的组合效应的结果。
