Open Access Nano Express

Fabrication of Porous Anodic Alumina with Ultrasmall Nanopores

GuQiao Ding12*, Rong Yang12, JianNing Ding12*, NingYi Yuan12 and YuanYuan Zhu12

Author Affiliations

1 Center for Low-Dimensional Materials, Micro-Nano Devices and System, Jiangsu Polytechnic University, 1 Ge Hu Road, Changzhou, 213164, Jiangsu, China

2 Key Laboratory of New Energy Source, Changzhou, 213164, China

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Nanoscale Research Letters 2010, 5:1257-1263  doi:10.1007/s11671-010-9634-x

Published: 19 May 2010

Abstract

Anodization of Al foil under low voltages of 1–10 V was conducted to obtain porous anodic aluminas (PAAs) with ultrasmall nanopores. Regular nanopore arrays with pore diameter 6–10 nm were realized in four different electrolytes under 0–30°C according to the AFM, FESEM, TEM images and current evolution curves. It is found that the pore diameter and interpore distance, as well as the barrier layer thickness, are not sensitive to the applied potentials and electrolytes, which is totally different from the rules of general PAA fabrication. The brand-new formation mechanism has been revealed by the AFM study on the samples anodized for very short durations of 2–60 s. It is discovered for the first time that the regular nanoparticles come into being under 1–10 V at the beginning of the anodization and then serve as a template layer dominating the formation of ultrasmall nanopores. Under higher potentials from 10 to 40 V, the surface nanoparticles will be less and less and nanopores transform into general PAAs.

Keywords:
Anodic alumina; Nanofabrication; Nanopore; Ultrasmall; Nanoparticle