Reactive Diffusion in Stressed Nanostructures

In nanoscaled objects, reaction-induced elastic stress and non-equilibrium vacancies can hardly relax. As a result, stresses may become outstandingly high, even approaching the theoretical strength of the material. A better understanding of the interrelation between diffusion, reaction and stress may lead to a perfect control of, for instance, the formation of hollow nanoparticles or hollow nanowires with a wide range of potential applications ranging from photonics to drug delivery.In order to accurately describe these phenomena we are developing a set of analytical equations solved numerically. These theoretical predictions are then put to the test by creating core-shell nanostructures produced by several techniques like ion beam sputtering, electroetching, electrodeposition… Reactive diffusion is achieved by annealing those nanostructures under different environments (Argon, Oxygen…). An accurate description of the diffusion processes at the atomic scale is then possible using a unique combination of characterization tools (SEM, TEM, Field Ion Microscopy, Atom Probe Tomography…).
Fig. 1: Kirkendall voiding during the oxidation of a metallic nanoparticle