Self-ordered Porous Anodic Alumina Templates by a Combinatory Anodization Technique in Oxalic and Selenic Acids

Authorsمهدیه احمدزاده ازناوه، محمد الماسی کاشی،محمد نورمحمدی، عبد العلی رمضانی
JournalJournal of Electronic Materials volume
Page number4787
Volume number50
Paper TypeFull Paper
Published At2021-06-02
Journal GradeISI
Journal TypeTypographic
Journal CountryIran, Islamic Republic Of

Abstract

A combinatory two-step anodization technique is presented to prepare self-ordered porous anodic alumina (PAO) templates. The first and second anodization steps are performed in oxalic and selenic acid at 40 V and 45 V, respectively, giving rise to 13-nm-diameter PAOs with high ordering and porosity of 1.4%. The anodization time for the second step is also changed to investigate the effect of the oxide layer thickness on the pore ordering, using field-emission scanning electron microscopy and fast Fourier transform analyses. Increasing the anodization time from 20 min to 1 h considerably improved the ordering and hexagonal domain structures. Further increasing the anodization time up to 8 h continuously deteriorated the ordering of the PAOs, although the nanopore growth rate remained almost constant. The fabrication of small-diameter PAOs in selenic acid is discussed and related to the electric field concentration at the oxide–electrolyte interface at the bottom of pores.

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