Porous alumina membranes with branched nanopores as templates for fabrication of Y-shaped nanowire arrays

Leszek Zaraska,Grzegorz D Sulka,Elżbieta Kurowska,Marian Jaskuła

doi:10.1007/s10008-012-1795-3

Leszek Zaraska, Grzegorz D Sulka + Show 2 more

Open Access

https://doi.org/10.1007/s10008-012-1795-3

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Abstract

Porous anodic alumina membranes with Y-branched and double-branched nanopores were fabricated by the stepwise reduction of anodizing potential during the second step of anodization carried out in 0.3 M oxalic acid. The process of nanoporous layer formation and influence of anodizing parameters on structural features of as-obtained anodic aluminum oxide (AAO) membranes were discussed in detail. The pore rearrangement process occurring after the potential decrease was investigated on the basis of the current density vs. time curves, and results were correlated with the field-emission scanning electron microscope images of the pore bottoms taken after different anodizing durations. It was found that the reorganization of nanopores begins after 600 and 500 s from the time of the potential reduction to 42 and 30 V and the process seems to be completed after about 900 and 800 s, respectively. The through-hole AAO membranes were used as templates for the fabrication of gold and polystyrene nanowires via electrochemical deposition and simple immersing in the polymer solution, respectively. The arrays of hierarchically branched nanowires were synthesized, and the dimensions of nanowires were consistent with the shape and structure of used AAO templates.

Highlights

A strong trend towards miniaturization of electronic devices could be observed, all disciplines of nanotechnology have become the most popular scientific areas in both academic science and industry [1, 2]
Great progress has been made in fabrication of simple 1D nanostructures over the last few years [4,5,6], the synthesis of multifunctional nanodevices often requires more complex nanostructures and, many research groups are working on development of methods for nanomanufacturing
The cross-sectional views of anodic aluminum oxide (AAO) templates with Ybranched and two level-branched nanopores are presented in Fig. 2a and b, respectively

Summary

Introduction

A strong trend towards miniaturization of electronic devices could be observed, all disciplines of nanotechnology have become the most popular scientific areas in both academic science and industry [1, 2]. In order to form AAO membranes with two level branched pores, after 30 min of anodizing at 42 V, the applied potential was reduced to 30 V and the duration of this step was 10, 20, 30, and 40 min (Fig. 1h). A subsequent reduction of the anodizing potential from 42 to 30 V leads to a second division of nanochannels (pink area “3” in the SEM image) and formation of the template with hierarchically branched nanopores.

Results

Conclusion