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.