The roles of temperature and thickness of barrier layer in the electrodeposition efficiency of nickel inside anodic alumina templates

Abstract

As a dielectric interface, the alumina barrier layer has so far been shown to influence the electrochemical deposition mechanism of different types of ions inside nanopores of anodic alumina templates. Here, the roles of temperature (Tb) and thickness of the barrier layer in the electrodeposition efficiency (EE) of nickel inside 45 nm pore diameter anodic alumina templates, made by the two step anodization process, are reported. By performing a pulsed electrodeposition method, the former role is investigated by increasing Tb from 10 to 50 C, whereas the latter role is realized by decreasing the final anodization voltage (Vth) from 40 V to 12, 16 and 20 V. While using Tb * 20 C and Vth = 16 V leads to a maximum EE of 65 % in the fabrication of 8.5 lm long nickel nanowires (NWs), the use of Tb * 50 C is indicative of the growth of approximately 3 lm long NWs, resulted from an EE of 20 %. However, by increasing Vth up to 20 V, EE reaches a plateau with an average value of 45 % as a function of Tb. On the other hand, although the crystallinity of the resulting NWs increases by increasing Tb up to 30 C, the magnetic properties are found to be almost independent of Vth and Tb.