Formation of tetrapod-shaped nanowires in the gas phase during the synthesis of ZnO nanostructures by carbothermal reduction.
We experimentally confirmed that charged ZnO nanoparticles were generated abundantly in the gas phase using a differential mobility analyzer (DMA). When they were size-selected by the DMA and captured on a grid for transmission electron microscopy, particles of 10 nm had a rod or tetrahedron shape, while particles larger than 10 nm tended to have a tetrapod shape. The tetrahedral particles seemed to be a seed for the growth of tetrapod nanowires. Although the growth of a tetrahedron shape enclosed by a close-packed plane (0002) of the hexagonal close-packed ZnO can be explained by the classical crystal growth theory, the growth of tetrapod nanowires can be better explained by the building block of charged nanoparticles generated in the gas phase.
Department of Materials Science and Engineering, Seoul National University, 599, Kwanak-ro, Kwanak-gu, Seoul 151-744, Republic of Korea.
Seong-Han
SH
Park
Jin-Woo
JW
Park
Chan-Soo
CS
Kim
Nong-Moon
NM
Hwang