Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
Nanoscale Res Lett. 2009 Nov 28;5(2):291-5. doi: 10.1007/s11671-009-9478-4.
The friction and shear strength of nanowire (NW)-substrate interfaces critically influences the electrical/mechanical performance and life time of NW-based nanodevices. Yet, very few reports on this subject are available in the literature because of the experimental challenges involved and, more specifically no studies have been reported to investigate the configuration of individual NW tip in contact with a substrate. In this letter, using a new experimental method, we report the friction measurement between a NW tip and a substrate for the first time. The measurement was based on NW buckling in situ inside a scanning electron microscope. The coefficients of friction between silver NW and gold substrate and between ZnO NW and gold substrate were found to be 0.09-0.12 and 0.10-0.15, respectively. The adhesion between a NW and the substrate modified the true contact area, which affected the interfacial shear strength. Continuum mechanics calculation found that interfacial shear strengths between silver NW and gold substrate and between ZnO NW and gold substrate were 134-139 MPa and 78.9-95.3 MPa, respectively. This method can be applied to measure friction parameters of other NW-substrate systems. Our results on interfacial friction and shear strength could have implication on the AFM three-point bending tests used for nanomechanical characterisation.
纳米线（NW）-衬底界面的摩擦和剪切强度对 NW 基纳米器件的电/机械性能和寿命有重要影响。然而，由于涉及到实验挑战，文献中很少有关于这个主题的报道，更具体地说，没有研究报道过单个 NW 尖端与衬底接触的情况。在这封信中，我们使用一种新的实验方法，首次报告了 NW 尖端与衬底之间的摩擦测量。该测量基于在扫描电子显微镜中进行的 NW 原位屈曲。发现银 NW 和金衬底之间以及 ZnO NW 和金衬底之间的摩擦系数分别为 0.09-0.12 和 0.10-0.15。NW 和衬底之间的附着力改变了真实接触面积，从而影响了界面剪切强度。连续介质力学计算发现，银 NW 和金衬底以及 ZnO NW 和金衬底之间的界面剪切强度分别为 134-139 MPa 和 78.9-95.3 MPa。该方法可用于测量其他 NW-衬底系统的摩擦参数。我们关于界面摩擦和剪切强度的结果可能对用于纳米力学特性的 AFM 三点弯曲测试有影响。
