Toward Submicrometer <i>c</i>-Oriented Nanoporous Films with Unidimensional Pore Network: AFI Film Morphology Control by Precursor Mixture Manipulation

c-Oriented, continuous AlPO4-5 and CoAPO-5 films with an average thickness of as low as 500 nm were synthesized by seeded growth. Growth behavior was controlled by appropriate manipulation of the precursor mixture without altering hydrothermal temperature. Employing crystalline seeds and precrystallization of the precursor mixture under proper conditions yielded a controllable and uniform growth of prism-shaped oriented crystals over the entire substrate surface. Systematically altering the water content affected growth direction, which was continuously tuned between in-plane and c-out-of-plane. The AFI films synthesized by the present work being the first thin, oriented, and well-intergrown ones represent promising materials for fabricating high-flux, unidimensional-pore membranes, for hosting and organizing molecules and clusters, and for growing arrays of monodisperse and ultrathin nanostructures, such as carbon nanotubes, inside the AFI channels targeting highly efficient optoelectronic devices.