Nanoporous titanium oxide synthesized from anodized Filtered Cathodic Vacuum Arc Ti thin films

Abstract

This paper describes the formation of self-organized nanopores in thin films of titanium prepared using a Filtered Cathodic Vacuum Arc (FCVA) deposition system. The post-deposition anodization was performed using 0.5% (wt) NH 4F in ethylene glycol and an aqueous based solution containing 0.5% (wt) NH 4F and 1 M (NH 4) 2SO 4 electrolytes. Homogenously distributed nanopores with dimensions in the range of 10 to 20 nm were obtained. Nanoporous TiO 2 thin films were obtained after annealing the anodized samples at 600 °C for 4 h. Scanning electron microscopy (SEM) and Raman spectroscopy were used to characterize these nanoporous films. Raman measurements revealed that the rutile TiO 2 polymorph dominates these structures along with imperfect titanium oxidation resulting in the formation of defect structures, particularly when aqueous electrolyte was used for the anodization.