Template-assisted growth of nano structured functional materials

Template-assisted growth is an important nano electrochemical deposition technique for synthesizing one-dimensional (1-D) nano structures with uniformly well-controlled shapes and sizes. A good template with well-defined dimensions is imperative for realizing this task. Porous anodic alumina (PAA) has been a favorable candidate for this purpose as it can be tailor-made with precise pore geometries, such as pore length and diameter as well as inter-pore distances, via the anodization of pure aluminium. This paper reports the fabrication of PAA templates and electrochemical synthesis of functional nano structures in the form of nano wires using PAA templates as scaffolds. Axial heterostructure and homogeneous nano wires formed by engineering materials configuration via composition and/ or layer thickness variations were fabricated for different functionalities. X-ray diffraction and imaging techniques were used to alucidate the microstructures, morphologies and chemical compositions of the nano wires produced. Due to their large surface area-to-volume ratios, and therefore high sensitivities, these functional nano structures have useful applications as critical components in nano sensor devices and various areas of nano technology. Potential applications include as hydrogen gas sensors in nuclear power plant for monitoring structural integrity of reactor components and containment building, as well as environmental monitoring of air pollution and leakages of toxic gases and chemicals. (Author)