title: Side-to-Side Cold Welding for Controllable Nanogap Formation from "Dumbbell" Ultrathin Gold Nanorods.
abstract: Cold welding has been regarded as a promising bottom-up nanofabrication technique because of its ability to join metallic nanostructures at room temperature with low applied stress and without introducing damage. Usually, the cold welding process can be done instantaneously for ultrathin nanowires (diameter <10 nm) in "head-to-head" joining. Here, we demonstrate that "dumbbell" shaped ultrathin gold nanorods can be cold welded in the "side-to-side" mode in a highly controllable manner and can form an extremely small nanogap via a relatively slow welding process (up to tens of minutes, allowing various functional applications). By combining in situ high-resolution transmission electron microscopic analysis and molecular dynamic simulations, we further reveal the underlying mechanism for this "side-to-side" welding process as being dominated by atom kinetics instead of thermodynamics, which provides critical insights into three-dimensional nanosystem integration as well as the building of functional nanodevices.
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China.|Shenzhen Research Institute, City University of Hong Kong , Shenzhen 518057, China.
authors.forename: Gaole
authors.initials: G
authors.lastname: Dai
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China.|Shenzhen Research Institute, City University of Hong Kong , Shenzhen 518057, China.
authors.forename: Binjun
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China.|Shenzhen Research Institute, City University of Hong Kong , Shenzhen 518057, China.
authors.forename: Shang
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China.|Shenzhen Research Institute, City University of Hong Kong , Shenzhen 518057, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong , Tat Chee Avenue, Kowloon, Hong Kong, China.|Shenzhen Research Institute, City University of Hong Kong , Shenzhen 518057, China.
authors.forename: Yajing
authors.initials: Y
authors.lastname: Shen
keywords: cold welding; gold nanorod; in situ TEM; nanogap; ultrathin nanowire