Diffusion‐Induced Void Evolution in Core–Shell Nanowires: Elaborated View on the Nanoscale Kirkendall Effect

In 2006, our group reported the fabrication of ultra‐long single‐crystal ZnAl 2 O 4 spinel nanotubes, starting from ZnO/Al 2 O 3 core–shell nanowires, involving the nanoscale Kirkendall effect. In this feature paper, we introduce our up‐to‐date results on the design of porous and hollow 1D nanostructures following this solid‐state interfacial reaction route. In particular, we present our recent understandings on void evolution induced by the unbalanced diffusion. We first give a short introduction on the distinctions of core–shell nanowires in interfacial nanoreactions, in contrast to other systems. Then we discuss the roles of desorption, stress, and/or defects on void evolution and nanotube formation. Our results demonstrate that the stress‐ and defects‐engineered diffusion mechanism can be used to specifically design hollow nanostructures, which will open up a new window in exploitation of the Kirkendall effect at the nanoscale.