Abstract:

We report the controlled fabrication of Ni nanotube and nanowire arrays by electrodeposition using anodic aluminum oxide (AAO) as a template. Ni nanotube arrays or nanowire arrays were obtained by changing the concentration of the electrolyte and the overpotential of the electrodeposition. The introduction of chelating species is crucial for nanotube formation because they can regulate the effective concentration of the electrolyte. A possible mechanism for the formation of the nanotubes/nanowires is proposed by considering the different contributing factors for the growth rate of the wall (Vw) and that of the bottom (Vb). Ni nanotube arrays can be obtained when Vw>Vb either at a high electrolyte concentrations (CNi2+) and at a more negative electrodeposition potential (Ued) or at a lower CNi2+ with a less negative Ued. Ni nanowire arrays can also be obtained when Vw≈Vb either at a high CNi2+ with a less negative Ued or at a lower CNi2+ with a more negative Ued. This mechanism may be used as a general strategy for the controlled synthesis of nanotube or nanowire arrays containing many kinds of metals such as Cu, Co, and Au etc.

Key words: Nanotube, Nanowire, Anodic aluminumoxide, Electrodeposition, Growth mechanism