Application of Isotropic AAO templates
Fabrication of metal nanowires
Fig. 3.1 General scheme for electrochemical deposition (ECD) of materials into porous AAO.
In general, to synthesize nanowires, the same general procedure can be applied irrespective of the materials to be deposited (Fig. 3.1). First, a thin Ag layer is deposited onto one face of an AAO membrane. This Ag layer serves as the working electrode in the deposition of desired materials. Next, a thin layer of sacrificial Ag (or Ni) is electrochemically deposited into the pores. After that, the desired material is electrochemically deposited. The resulting nanowires/AAO composite sample then is dipped into HNO3 solution to remove the Ag working electrode layer and the sacrificial layer (Ag or Ni). The nanowires can be collected by dissolving the AAO template using an appropriate AAO etchant (typically, KOH or H3PO4). The choice of oxide etchant depends on the material deposited; the etchant solution should not react with the nanowire material. The diameter of the resulting nanowires is determined by the pore size of the porous AAO template, while their length is proportional to the total amount of charge passed during the electrochemical deposition. Various metal nanowires (e.g., Au, Ag, Pt, Ni, Pb, Cu, Zn, Co, Sb) have been synthesized in porous AAO templates. These single component 1D metallic nanowires have been used as model systems for systematically investigating various research issues in chemistry and physics, for example, the catalytic, magnetic, thermoelectric, and plasmonic properties of 1D nanostructures.
Reference:
Science Advances, 2016, 2, e1501227
Nature Photonics, 2016, 10, 393–398