Multiply twinned aluminum nanoparticles

Multiply twinned oxide-free Al nanoparticles, with diameters of 2 nm to 50 nm, were obtained from metastable θ-Al₂O₃ particles by an electron beam irradiation technique using a high-resolution transmission electron microscope on a room-temperature stage. The phenomenon of formation, the morphology and the multiply twinned structures of the Al nanoparticles were investigated by the in situ observation method. It is clear that the morphology of polyhedral multiple twinned Al nanoparticles were mostly decahedra, and that the decahedra were categorized into pentagonal, spherical, ellipsoidal, and lamellar morphology.