Template-based synthesis of Ni nanorods on silicon substrate

Free-standing nickel (Ni) nanorods were successfully prepared by pulsed electrodeposition using porous alumina membrane (PAM) on titanium (Ti) pre-coated silicon (Si) substrate. Initially, Si substrate was coated with subsequent layers of Ti (∼200 nm) and Al (∼600 nm) by sputtering process. The PAM/Ti/Si structure was fabricated by a two-step anodization in 0.3 M oxalic acid under a constant voltage of 40 V, and then used to grow Ni nanorods by pulsed electrodeposition. Finally, an Al layer was deposited on the Ni nanorods. The relationship between the pore-widening time and the pore diameter of the PAM on Si was also investigated. Field emission scanning electron microscopy (FESEM) was employed to observe the morphology of PAM, Ni nanorods and Al/Ni heterostructure. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to study the morphological and structural properties of Ni nanorods, respectively. Also, the compositional properties of the samples were characterized by energy dispersive X-ray spectra (EDS). The pore diameter and the pore length of the PAM were approximately 54.2 ± 12.2 nm and 800 nm, respectively. The Ni nanorods stand perpendicularly on the substrate, whose diameter and length were similar to the PAM. The Ni nanorods give an XRD pattern of face-centered cubic crystal structure. Ni nanorods with deposited a layer of Al have the potential application of a heat source or energetic material in the silicon-based micro-electromechanical systems (MEMS) compatible device.