In Situ Domain-Confined Epitaxial Regrowth of Individual Nanoparticle: Implications for Nanofabrication

Electron beam irradiation has become a powerful tool for designing material structures and studying nanostructure growth down to the individual nanoparticle (NP) level; the method has important fundamental research implications and potential technological applications. However, controlling NP growth under high-energy bombardment is challenging owing to the rapid and unconstrained evolution of NPs during nanofabrication. Herein, a real-time in situ study of epitaxial regrowth of partially sublimated NPs was performed using an FEI Titan 80-300 transmission electron microscope operated at 300 kV. Hybrid NPs containing Ag, Cu, and CuAg with particle sizes of 2-20 nm were obtained via electron beam irradiation of large (35 nm) CuAg NPs at 500 °C. NPs sublimed with increased temperature. Interestingly, domain-confined layer-by-layer epitaxial regrowth on the Ag{111} and {100} facets was observed for partially sublimated NPs. The newly grown part was mostly Ag, as determined using energy-dispersive X-ray spectroscopy. Electron beam irradiation was a key activator for epitaxial regrowth. This study provides real-time regrowth dynamics information at an atomic level, providing new insights into nanostructure growth control in gaseous environments, finding promising applications in nanofabrication.