In situ SEM electromechanical characterization of nanowire using an electrostatic tensile device

This paper presents a method for simultaneously performing mechanical tensile test and electrical test on nanowire in SEM. For this purpose, an electrostatic tensile device is designed, fabricated and tested. In order to simplified the testing system, microforce sensor beam is used to measure the tensile force applied to the nanowire instead of traditional capacitive force sensor. Special care is taken on the design and fabrication process to improve the resolution of mechanical measurement by SEM imaging. Mechanical properties such as Young's modulus, elastic limit and fracture strength, and electrical resistance of nanowire can be obtained in the process of tensile testing using this device. Cu nanowire and SiC nanowire are tested as examples in this paper. Smaller Young's modulus is found in both nanowires due to the imperfection in crystallization. On the other hand, electrical properties under different tensile stress are characterized for both nanowires. Nonlinear and identical I-V curves are revealed for Cu nanowire, and linear I-V curves and the piezoresistive effect are revealed for SiC nanowire. The gauge factor of SiC nanowire is calculated and turns out to be compatible with the values of bulk SiC published in the literature.