Ultra-narrow 12nm pore diameter self-ordered anodic alumina templates (original) (raw)
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Highly ordered anodic alumina nanotemplate with about 14 nm diameter
Korean Journal of Chemical Engineering, 2008
A novel method for the fabrication of highly ordered nanopore arrays with very small diameter of 14 nm was demonstrated by using low-temperature anodization. Two-step anodization was carried out at 25 V, sulfuric acid concentration of 0.3 M, and electrolyte temperature of −15 o C. After anodization, a regular pore array with mean diameter of 14 nm and interpore distance of 65 nm was formed. The pore diameter and regular arrangement were confirmed by scanning electron microscopy (SEM) and fast Fourier transformation (FFT), respectively. The present results strongly suggest that the diameter of pores in a highly ordered alumina template can be reduced by lowering the anodization temperature.
Fabrication of highly ordered pore array in anodic aluminum oxide
Korean Journal of Chemical Engineering, 2002
− − − −Highly ordered pore array in anodic aluminum oxide was fabricated by anodizing pure aluminum. The order of a pore array was affected by anodizing voltage, electrolyte temperature, and first anodizing time. A regular pore array with mean diameter of 24 nm and interpore distance of 109 nm could be formed by two-step anodization at 40 V, oxalic acid concentration of 0.3 M and electrolyte temperature of 15 o C. The measured interpore distance showed linearity with anodizing voltage. The diameter of pores was adjusted by pore widening treatment in a 5 wt% phosphoric acid solution at 30 o C after two step anodization. The mechanism of self-arrangement of pores could be explained by the repulsive interaction between the pore walls.
On the Growth of Highly Ordered Pores in Anodized Aluminum Oxide
Chemistry of Materials, 1998
It is now established that hexagonally ordered domain structures can be formed in anodic alumina films by repeated anodization and stripping of the porous oxide. We find that the domain size is a linear function of time and increases with temperature. The pore density is initially high but decreases with anodizing time, as dominant pores deepen. Very small pores exist in native oxide in air or nucleate after electropolishing. Pore growth may start when the electric field increases at the pore bottoms, and acid dissolves the oxide locally.
Thin Solid Films, 2018
Ordered porous anodic alumina (PAA) templates are of great interest as they facilitate the future development of nanodevices. The present study focuses on the impact of substrates with di fferent crystallographic orientations on the template's pore structure. Characteristics such as pore diameter, interpore distance, pore regularity, porosity, and circularity are calculated as a function of the anodization potential for three di fferent Al crystal orientations. The presented experiments reveal that the di fferent crystallographic orientations mainly impact the pore ordering, while other structural parameters, such as the pore diameter and interpore distance, are not significantly affected.
Fabrication of Nanomaterials on Porous Anodic Alumina Template Using Various Techniques
2015
Porous anodic aluminum oxide film is a versatile template for the fabrication of nanomaterials. Porous alumina can be fabricated electrochemically through anodic oxidation of aluminum by self-organization method yielding highly ordered arrays of nanoholes. Various techniques such as chemical vapor deposition, electrodeposition, spin coating, dip coating, physical vapor deposition are elaborated for the fabrication of nanomaterials using porous anodic alumina as template.
Ordered three-dimensional interconnected nanoarchitectures in anodic porous alumina
Nature communications, 2014
Three-dimensional (3D) nanostructures combine properties of nanoscale materials with the advantages of being macro-sized pieces when the time comes to manipulate, measure their properties or make a device. However, the amount of compounds with the ability to self-organize in ordered 3D nanostructures is limited. Therefore, template-based fabrication strategies become the key approach towards 3D nanostructures. Here we report the simple fabrication of a template based on anodic aluminium oxide, having a well-defined, ordered, tunable, homogeneous 3D nanotubular network in the sub 100-nm range. The 3D templates are then employed to achieve 3D, ordered nanowire networks in Bi2Te3 and polystyrene. Finally, we demonstrate the photonic crystal behaviour of both the template and the polystyrene 3D nanostructure. Our approach may establish the foundations for future high-throughput, cheap, photonic materials and devices made of simple commodity plastics, metals and semiconductors.
Nanomaterials
A reliable, scalable, and inexpensive technology for the fabrication of ordered arrays of metal nanoparticles with large areal coverage on various substrates is presented. The nanoparticle arrays were formed on aluminum substrates using a two-step anodization process. By varying the anodization potential, the pore diameter, inter-pore spacing, and pore ordering in the anodic aluminum oxide (AAO) template were tuned. Following a chemical etch, the height of the pores in the AAO membrane were reduced to create a dimpled membrane surface. Periodic arrays of metal nanoparticles were subsequently created by evaporating metal on to the dimpled surface, allowing for individual nanoparticles to form within the dimples by a solid state de-wetting process induced by annealing. The ordered nanoparticle array could then be transferred to a substrate of choice using a polymer lift-off method. Following optimization of the experimental parameters, it was possible to obtain cm2 coverage of metal n...
Revisiting anodic alumina templates: from fabrication to applications
Nanoscale, 2021
Anodic porous alumina,-AAO-(also known as nanoporous alumina, nanohole alumina arrays,-NAAor nanoporous anodized alumina platforms,-NAAP-) has opened new opportunities in a wide range of fields, and is used as an advanced photonic structure for applications in structural coloration and advanced optical biosensing based on the ordered nanoporous structure obtained and as a template to grow nanowires or nanotubes of different materials giving rise to metamaterials with tailored properties. Therefore, understanding the structure of nanoporous anodic alumina templates and knowing how they are fabricated provide a tool for the further design of structures based on them, such as 3D nanoporous structures developed recently. In this work, we review the latest developments related to nanoporous alumina, which is currently a very active field, to provide a solid and thorough reference for all interested experts, both in academia and industry, on these nanostructured and highly useful structures. We present an overview of theories on the formation of pores and self-ordering in alumina, paying special attention to those presented in recent years, and different nanostructures that have been developed recently. Therefore, a wide variety of architectures, ranging from ordered nanoporous structures to diameter changing pores, branched pores, and 3D nanostructures will be discussed. Next, some of the most relevant results using different nanostructured morphologies as templates for the growth of different materials with novel properties and reduced dimensionality in magnetism, thermoelectricity, etc. will be summarised, showing how these structures have influenced the state of the art in a wide variety of fields. Finally, a review on how these anodic aluminium membranes are used as platforms for different applications combined with optical techniques, together with principles behind these applications will be presented, in addition to a hint on the future applications of these versatile nanomaterials. In summary, this review is focused on the most recent developments, without neglecting the basis and older studies that have led the way to these findings. Thus, it gives an updated state-of-the-art review that should be useful not only for experts in the field, but also for non-specialists, helping them to gain a broad understanding of the importance of anodic porous alumina, and most probably, endow them with new ideas for its use in fields of interest or even developing the anodization technique.
Controlling the anodizing conditions in preparation of an nanoporous anodic aluminium oxide template
Materials Science-Poland, 2014
Porous anodic aluminium oxide (AAO) template is commonly used in the synthesis of one-dimensional nanostructures, such as nanowires and nanorods, due to its simple fabrication process. Controlling the anodizing conditions is important because of their direct influence on the size of AAO template pores; it affects the size of nanostructures that are fabricated in AAO template. In present study, several alumina templates were fabricated by a two-step electrochemical anodization in different conditions, such as the time of first process, its voltage, and electrolyte concentration. The effect of these factors on pore diameters of AAO templates was investigated using scanning electron microscopy (SEM).