TiO₂ ALD Coating of Amorphous TiO₂ Nanotube Layers: Inhibition of the Structural and Morphological Changes Due to Water Annealing.

ABSTRACT: The present work presents a strategy to stabilize amorphous anodic self-organized TiO₂ nanotube layers against morphological changes and crystallization upon extensive water soaking. The growth of needle-like nanoparticles was observed on the outer and inner walls of amorphous nanotube layers after extensive water soakings, in line with the literature on water annealing. In contrary, when TiO₂ nanotube layers uniformly coated by thin TiO₂ using atomic layer deposition (ALD) were soaked in water, the growth rates of needle-like nanoparticles were substantially reduced. We investigated the soaking effects of ALD TiO₂ coatings with different thicknesses and deposition temperatures. Sufficiently thick TiO₂ coatings (?8.4 nm) deposited at different ALD process temperatures efficiently hamper the reactions between water and F^- ions, maintain the amorphous state, and preserve the original tubular morphology. This work demonstrates the possibility of having robust amorphous 1D TiO₂ nanotube layers that are very stable in water. This is very practical for diverse biomedical applications that are accompanied by extensive contact with an aqueous environment.

SUBMITTER: Ng S 

PROVIDER: S-EPMC6367259 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature