In Situ Measurement of the Kinetic Friction of Si Nanowires on SiC Substrates in SEM with a Microprobe

This research introduces a kinetic friction modeling and measurement method for silicon nanowires (NWs) and silicon carbide substrates. The NW was pushed to slide by the micro-force probe at a constant speed. Under the conditions of kinetic friction and deformation of the nanowires, the silicon nanowires are in equilibrium during the measurement. Under this condition, the value measured by the micro-force probe is the total kinetic friction force. The thermal insulation connector is used to isolate the heat conduction to the micro-force probe to avoid the influence of temperature rise on the measurement result. The Faraday cup was used to measure the surface current in the scanning electron microscope (SEM). The appropriate parameters of SEM were chosen according to the surface current to reduce the influence of the charging effect on the measurement results. The high sensitivity of the micro-force probe is used to ensure that there is no contact between the probe and the substrate, thereby avoiding the interference of the pre-load force. The entire experiment process was monitored in real-time to improve the stability of the measurement. The study in this paper found that the shear stress of silicon nanowires is 1.05 \pm 0.32\text{MPa}.