In Situ TEM Observation of a Microcrucible Mechanism of Nanowire Growth

Boston, Rebecca, Zoe Schnepp, Yoshihiro Nemoto, Yoshio Sakka, Simon R. Hall, 2014
Fusion TEM holder tip
Image courtesy of Science

Abstract

The growth of metal oxide nanowires can proceed via a number of mechanisms such as screw dislocation, vapor-liquid-solid process, or seeded growth. Transmission electron microscopy (TEM) can resolve nanowires but invariably lacks the facility for direct observation of how nanowires form. We used a transmission electron microscope equipped with an in situ heating stage to follow the growth of quaternary metal oxide nanowires. Video-rate imaging revealed barium carbonate nanoparticles diffusing through a porous matrix containing copper and yttrium oxides to subsequently act as catalytic sites for the outgrowth of Y2BaCuO5 nanowires on reaching the surface. The results suggest that sites on the rough surface of the porous matrix act as microcrucibles and thus provide insights into the mechanisms that drive metal oxide nanowire growth at high temperatures.

Impact Statement

The observation of molten nanoparticles migrating through a porous yttrium and copper-rich matrix, which produces nanowire outgrowth.