| One dimensional nanostructures have become the focus of intensive research due to their unique properties and potential applications in high density nanoscale devices including sensors, optoelectronics, and magnetic memories. In early 1990s Martin and his coworkers pioneered the use of hard templates in the synthesis of metal and polymer tubes, rods and wires by electrochemical or electroless deposition into a porous anodic alumina oxide (PAAO) membrane followed by dissolution of the membrane. Afterwards this approach is widely employed to synthesize various kinds of nanoarrays including metal, semiconductor and polymer ones.Two-stepped anodization was taken to fabricate PAAO in oxalic acid solution, etc. Samples on each stage of experiment were observed to help delve into the details. The effects on the strcture of PAAO rendered by various conditions in experiment were studied and a collection of existen theories about the growth of PAAO was compiled. The impact resulting from different electrolyte and different voltage was generalized. Phosphoric acid solution and sulphuric acid solution were compared when applied to remove barrier layer.Alumina oxide nanowires obtained after a two-stepped anodization of an aluminum foil are characterized by using scanning electron microscopy. A distinct growth mechanism is proposed for these nanowires in comparison with that for those formed by using chemical etching methods. An electric field along with stress is ineluctable to the growth of these nanowires while a nano-imprinted metal surface of the aluminum foil plays a key role. Nanorods with unprecidented order were found after almost the same process. The study on their growth condition and forming mechanism would be a pioneering work and needs further work.Based on the template of PAAO, electric deposition, Sol-Gel deposition was adopted to grow tin oxide nanowires and their array which were characterized by using SEM.
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