Size effects on the stabilization and growth of tetragonal ZrO2 crystallites in a nanotubular structure.

The size effects on the stabilization of ZrO2 polymorphs in nanoscale and the growth behavior of their crystallites in 1-D nanotubular structures were investigated. Polycrystalline nanotubular structures of ZrO2 with tetragonal nanocrystallites were fabricated using nanoporous polycarbonate (PC) templates and atomic layer deposition (ALD). The as-prepared ZrO2 nanotubes showed polycrystalline structures of stabilized tetragonal polymorphs at room temperature. The wall thickness of the ZrO2 nanotubes was well controlled by the number of ALD cycles. Faster growth of the tetragonal nanocrystallites was observed in the nanotubes with a 50 nm outer diameter, than those of 200 nm. The Gibbs-Thompson relation can be used to explain the observed nanosize effects on the growth of the tetragonal ZrO2 nanocrystallites.