The filamentary growth of metals

Abstract

One-dimensional structures are starting to have impact in modern technological device design. A brief history of the fabrication of metal structures in such geometries is presented. At the dawn of modern science, in 1574, a recipe was published for the formation of “metallic grass”. This ancient recipe is reintroduced into modern technology using physical vapor deposition techniques to grow nanowhiskers. Defects in dewetting layers on various substrates are proven to act as nucleation sites for the whisker growth. This general approach is shown for Cu, Ag and Co nanostructures. The whiskers are of perfect crystal structure, devoid of defects and flaws and freestanding on the substrates. A phenomenological but energetically justified growth model is presented. The unique mechanical stability of these structures is shown by bending experiments. The theoretical limit of the mechanical strength is reached reproducibly.