Formation of Thick Porous Anodic Alumina Films and Nanowire Arrays on Silicon Wafers and Glass

Abstract

A method for the fabrication of thick films of porous anodic alumina on rigid substrates is described. The anodic alumina film was generated by the anodization of an aluminum film evaporated on the substrate. The morphology of the barrier layer between the porous film and the substrate was different from that of anodic films grown on aluminum substrates. The removal of the barrier layer and the electrochemical growth of nanowires within the ordered pores were accomplished without the need to remove the anodic film from the substrate. We fabricated porous anodic alumina samples over large areas (up to 70 cm2), and deposited in them nanowire arrays of various materials. Long nanowires were obtained with lengths of at least 9 μm and aspect ratios as high as 300. Due to their mechanical robustness and the built‐in contact between the conducting substrate and the nanowires, the structures were useful for electrical transport measurements on the arrays. The method was also demonstrated on patterned and non‐planar substrates, further expanding the range of applications of these porous alumina and nanowire assemblies.

Conductive films of ordered nanowire arrays

“…To date, there are few studies on the electrical properties of organized arrays of nanowires. 53 The lack of electrical characterisation of nanowire arrays stems from the difficulties in placing nanowires into organized structures. However, the inclusion of nanowires in MTFs or AAO membranes combined with conductive atomic force microscopy (C-AFM) has the potential to yield the electrical properties of thousands of individual nanowires that are aligned in ordered architectures.…”

Porous alumina thin films on conductive substrates for templated 1-dimensional nanostructuring

“…The concomitant electrically insulating barrier layer, however, is one of the main limitations to AAO technology and its selective removal has not yet been standardized, although progress has been made by several authors [8][9][10][11][12][13][14][15][16]. When anodizing Al as a thin film, on a multilayered substrate with conductive interstitial layers, the final morphology of the barrier layer is heavily influenced by these underlying materials [17].…”

Vertically Aligned Pd Nanowires for Glucose Oxidase Bioanode

“…Pd nanowire array electrodes are high surface area three-dimensional bioanode, which are fabricated from Anodized Aluminum Oxide (AAO) template electrodeposition method [15][16][17]. These fabricated AAO templates are inherently ordered in nature and exhibits a highly self-arranged hexagonal array that permit them to be used as a template for the electrodeposition of metal species [18]. The nanowires formed on the electrode surface were characterized by Scanning Electron Microscopy (SEM).…”