Fabrication of porous anodic alumina with ultrasmall nanopores.

Gu Qiao Ding,Yuan Yuan Zhu,Ning Yi Yuan,Jian Ning Ding,Rong Yang

doi:10.1007/s11671-010-9634-x

Gu Qiao Ding, Yuan Yuan Zhu + Show 3 more

Open Access

https://doi.org/10.1007/s11671-010-9634-x

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Journal: Nanoscale Research Letters	Publication Date: May 19, 2010
Citations: 33	License type: cc-by

Affiliation: Jiangsu University of Technology

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.

Highlights

Self-ordered porous anodic alumina (PAA) has attracted considerable attention due to its utilization as a host or template to fabricate diverse nanostructures for different applications, such as electronic, magnetic and optoelectronic nanodevices [1–3]
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 serve as a template layer dominating the formation of ultrasmall nanopores
Another typical PAA with ultrasmall nanopores was fabricated in the mixture of 20 wt% H2SO4, 1 wt% citric acid and 1 wt% Al2(SO4)3 under 15°C and 10 V for 30 min

Summary

Introduction

Self-ordered porous anodic alumina (PAA) has attracted considerable attention due to its utilization as a host or template to fabricate diverse nanostructures for different applications, such as electronic, magnetic and optoelectronic nanodevices [1–3]. In order to further confirm the formation of ultrasmall nanopores, we used FESEM and TEM to characterize the PAA samples anodized at 10 V in 0.3 M oxalic acid.

Results

Conclusion