Tailoring atomic diffusion for in situ fabrication of different heterostructures

Atomic diffusion has been recognized as a particularly powerful tool in the synthesis of heterostructures. However, controlled atomic diffusion is very difficult to achieve in the fabrication of individual nanostructures. Here, an electrically driven in situ solid-solid diffusion reaction inside a TEM is reported for the controlled fabrication of two different hetero-nanostructures in the Ag-Te system. Remarkably, the morphology and structure of the as-formed heterostructures are strongly dependent on the path of atomic diffusion. Our experiments revealed that the surface diffusion of Te atoms to Ag nanowires leads to a core-shell structure, while the bulk diffusion of Ag atoms give rise to a Ag2Te-Te segmented heterostructure. Heat released by Joule heating caused the surface diffusion process to be replaced by bulk diffusion and thereby determined the structure of the final product. Our experimental results provide an insight into solid-state diffusion reactions under an electric field and also propose a new process for the fabrication of complex nanostructures. Atomic diffusion is a powerful tool for the synthesis of heterostructures, even though controlled atomic diffusion is difficult to achieve. Here, the authors control solid-solid atomic diffusion between an Ag nanowire and a Te nanowire, producing 1D heterostructures by applying an electrical bias inside a TEM.

Automated summary

Atomic diffusion is a powerful tool for the synthesis of heterostructures, but controlled atomic diffusion remains challenging. In this study, the authors demonstrate controlled solid-solid atomic diffusion between Ag nanowires and Te nanowires to produce 1D heterostructures by applying an electrical bias inside a TEM.