Electrochemical growth of ordered nickel nano-rods within a composite structure of anodic-alumina-membrane/metal/silicon substrate.

Electrochemical growth of highly oriented Ni nano-rods within the arrays of anodic alumina pores has various important applications including magnetic, sensor and field-emission displays. Applicability of ordered nano-rods in practical devices requires proper designing of the structure with high stability and robustness. Anodic alumina membrane grown on Si substrate offers less fragile, stable, compact and robust structure as a host for nano-rod growth through the nanopores. We have fabricated highly ordered Ni-nanorods via cost-effective electrochemical deposition process within a porous alumina matrix. The device structure composed of Ni nano-rod/porous-alumina/tantalum/silicon-substrate. Metallic Ta is used as the electrode for Ni electrodeposition. Electron Microscopic images depict the highly uniform growth of Ni nano-rods through the alumina pores with nano-rod length around 100 nm. Energy dispersive X-ray analysis verifies the presence of Ni within the sample. One of the important applications of Ni nano-rods is the field emission devices. The host alumina template in the alumina/nano-rod/Si structure is believed to provide necessary stability of the proposed device for practical applications. Ni nano-rods encapsulated within the alumina pores with a top metallic layer can be used as a field-emission device for potential low power panel applications.