Self-elongated growth of nanopores in annealed amorphous Ta2O5 films

Nanoporous Ta2O5 films with oriented and elongated nanopores have been prepared by a technique which utilizes the accumulation of free volume during the crystallization of amorphous Ta2O5 annealed above 973 K. The transmission electron microscopy analyses revealed that voids were elongated in the [1 0 0] direction perpendicular to the longitudinal b axis of the orthorhombic structure. The self-assembly of a significant amount of oriented nanovoids can be contributed to the strong anisotropic crystal structure of orthorhombic Ta2O5.