Uncovering the machining mechanism of polycrystalline gold nanowires by nanoskiving

Abstract

The unique size effects of nanowires have inspired their implementation in superconducting materials, micro/nano electromechanical systems, and flexible devices. Nanoskiving technology has demonstrated significant potential for nanowire preparation owing to the low equipment requirements, simple operation, and wide material compatibility compared with traditional lithographic nanofabrication methods. However, the increasing application of nanowires has imposed strict requirements regarding their microstructure, morphology, and size accuracy. Limited research efforts have focused on the nanowire formation mechanism during nanoskiving, and therefore, it is difficult to prepare high-quality nanowires using this technique. The present study investigates the effects of the cutting depth on the machining (nanoskiving) mechanism of polycrystalline gold nanowire preparation. Molecular dynamics simulations indicate that the interference of grain boundaries and the extrusion of the tool lead to the formation and evolution of sub-grains. The specific energy, dislocation density, and nanowire thickness deviation all increase exponentially with decreasing depth of cut, thereby revealing a significant size effect. The nanowire microstructures, morphology, and dimensions are measured experimentally using transmission electron microscopy and atomic force microscopy, and the results are consistent with the simulations. This work provides insights into the cutting deformation mechanism during the nanoskiving of polycrystalline gold materials and contributes to the precise and controllable fabrication of nanostructures by the nanoskiving method.