Self-Ordered Porous Anodic Alumina with Large Pore Intervals: Review on Experimental and Theoretical Research

Abstract

The production of self-organized porous anodic alumina (PAA) with large intepore intervals (Dc > 380 nm) is still under development. The PAA is very interesting for applications in optics and photonics where a large-scale periodicity corresponding to visible or infrared light is required. However, the process remains challenging because it usually involves anodization under high voltages that is prone to instabilities and breakdown events. The basic problem relies on harnessing the electrochemical conditions to find a balance between various phenomena that occur during transformation from aluminum to porous alumina. The overall process is quite complicated but it is believed that regularity of pore formation is governed mainly by an equilibrated counter-ion (Al3+ and electrolyte anions A-) exchange at the electrolyte/oxide interface. Accordingly, a new concept of PAA growth is proposed which takes into account three basic elements of field-enhanced dissolution, plastic flow, and electro-convective models. The results on recent achievements in the high-voltage anodization is discussed focusing on the strategies that led to the self-ordering growth of PAA with large Dc. It is hoped that the review will contribute to better designing of anodization parameters to produce the ordered porous material with desired morphology.

Influence of Induced Local Stress on The Morphology of Porous Anodic Alumina at The Initial Stage of Oxide Growth

“…Similar results were obtained earlier. 8,28,29 As known, the compression stress arises in the oxide layer during aluminum anodizing due to the volume expansion of aluminum oxide. [30][31][32][33][34][35] Simultaneously, tensile stress occurs in the aluminum layer due to structural deformation.…”

Influence of Anodization Mode and Temperature on the Optical Properties of Photonic Crystals Based on Porous Anodic Alumina

“…The j and U behavior is typical for the processes affected by diffusional phenomena. 19,29 It is known that as long as the diffusion of ions (such as OH − , O 2− , electrolyte species) from bulk electrolyte to the pore base occurs much faster than the ion migration through the barrier layer, the alumina growth is not limited by diffusion. However, with increasing thickness of PAA the diffusion becomes more and more inefficient in replenishing an appropriate amount of ions to the reaction spot contributing to the instable behavior of j in the U t and U q modes and U in the j t mode (e.g.…”

Hysteresis, Rectification, and Relaxation Times of Nanofluidic Pores for Neuromorphic Circuit Applications

“…Figure 10 shows the nanopores made from anodic oxides of alumina (Al 2 O 3 ) generated from valve metals via anodization. [44,97,[102][103][104][105] In this case the pore is blocked at the bottom but the ions diffuse across the barrier oxide layer. A selective flow of ions such as potassium (K + ) and chloride (Cl -) ions from salt electrolytes across the bottom barrier of the nanopores results in the characteristic ionic current rectification.…”