Siowwoon Ng

Ideally Hexagonally Ordered TiO2 Nanotube Arrays

Abstract Ideally hexagonally ordered TiO2 nanotube layers were produced through the optimized anodization of Ti substrates. The Ti substrates were firstly covered with a TiN protecting layer prepared through atomic layer deposition (ALD). Pre‐texturing of the TiN‐protected Ti substrate on an area of 20×20u2005μm2 was carried out by focused ion beam (FIB) milling, yielding uniform nanoholes with a hexagonal arrangement throughout the TiN layer with three different interpore distances. The subsequent anodic nanotube growth using ethylene‐glycol‐based electrolyte followed the pre‐textured nanoholes, resulting in perfectly ordered nanotube layers (resembling honeycomb porous anodic alumina) without any point defects and with a thickness of approximately 2u2005μm over the whole area of the pattern.

Fabrication of titanium dioxide nanotubes in fluoride-free electrolyte via rapid breakdown anodization

This paper presents the study on the growth of bundled titanium dioxide (TiO2) nanotubes via rapid breakdown anodization method by using chloride-based electrolyte. The effects of different ratios of deionized water (DI) to ethylene glycol (EG) on the morphological, structural and photoelectrochemical properties of the TiO2 nanotubes generated were investigated. Different ratios of DI:EG showed significant changes on the diameter of nanotube bundles. Besides that, X-ray diffraction measurements revealed that anatase phase of titanium dioxide appeared within the thermally treated samples. Scherrer method was applied to calculate the mean crystallite size of the crystal growth in this study. The photoelectrochemical properties of TiO2 nanotube bundles were characterized by using three-electrode photoelectrochemical cell and showed good photocurrent response and stability.