Nano Manipulation and Assembly of Silver Nanowires In Situ for Advanced Fabrication

Sliver nanowires (Ag NWs) are promising building blocks for electronic nanodevices, and therefore, their precise movement and assembly are urgently needed. Here, molecular dynamics simulations are conducted to model the manipulation of Ag NWs on a silicon substrate using a tungsten (W) probe. The focus is on understanding the deformation and motion mechanisms of the Ag NWs induced by the moving probe. Throughout the manipulation process, Ag NWs undergo four distinct stages: plastic deformation, deformation extension, a hybrid stage, and either movement or fracture. At the contact area between the probe and the Ag NWs, as well as in regions of stress concentration, Ag atoms are observed to transition from FCC to HCP, BCC, and even amorphous states. Notably, the BCC phase serves as an intermediate transition state during this lattice transformation. The manipulation parameters, particularly the velocity and displacement of the probe, significantly influence the outcome of the Ag NWs. High-speed manipulation with small displacements tends to result in Ag NW fracture, whereas low-speed manipulation with larger displacements facilitates the bending or movement of the Ag NWs. Drawing from the observed deformation behaviors, a nanomanipulation platform integrated within a scanning electron microscope (SEM) was developed. This platform enables the in situ pushing, cutting, bending, and rotating of Ag NWs using a W probe, employing various probe feeding strategies. By combination of two or more of these manipulation operations, complex close-loop structures, such as triangles and hexagons, were successfully assembled via Ag NWs. This research offers valuable insights into the precise and controlled manipulation of Ag NWs, paving the way for the fabrication of sophisticated, high-performance nanodevices.