KR100830834B1 - Anodic Aluminum Oxide Template - Google Patents

Abstract

       The present invention relates to an anodized aluminum template having an excellent precision of micropores filled with nano metals by having a (100) texture (crystal orientation).

The present invention, a substrate of aluminum material; An anodization layer formed on one side of the substrate; And a plurality of nano-sized micropores formed in the anodization layer, wherein the substrate provides an anodized aluminum oxide template having a structure of (100) texture.

According to the present invention, the anodized aluminum oxide template of the (100) texture has a better planar micropore shape and the degree of alignment of the cross-sectional micropores than the other (110) and (111) textures of the aluminum oxide template. Therefore, according to the present invention, it is possible to obtain a nanorod having excellent uniformity in terms of diameter and length.

Assembly tissue, crystal orientation, anodized aluminum template, aluminum substrate, nano size micropore, nano rod

Description

Anodic Aluminum Oxide Template

       Figures 1a) to 1c) is a block diagram showing an anodized aluminum oxide (AAO Template) according to the present invention,

       a) drawing cutaway section, b) drawing longitudinal section, c) drawing plan view;

       Figure 2 shows an anodized aluminum oxide template having a different structure than the anodized aluminum template according to the present invention,

       a) is a planar photograph showing micropores of (100) aggregated tissue,

       b) is a planar photograph showing micropores of (110) aggregated tissue,

       c) is a planar photograph showing the micropores of the (111) texture;

       Figure 3 is a flow chart showing step by step the manufacturing process of the anodized aluminum template according to the present invention;

       Figure 4 is a plan view and side cross-sectional view showing a state in which micropores are expanded in the anodized aluminum oxide template according to the present invention;

       FIG. 5 is a graph illustrating, by time zone, a state in which the thickness of the micropores is expanded and the thickness of the substrate is increased as the etching proceeds in the anodized aluminum oxide template according to the present invention;

       6 is a graph showing XRD patterns of anodized aluminum oxide templates having aluminum single crystals of (100), (110) and (111) textures;

       Figure 7 is a photograph of the Ni nanorods obtained from the anodized aluminum oxide template according to the present invention.

       <Explanation of symbols for the main parts of the drawings>

1 .... anodized aluminum template according to the invention

1 '... 110) Anodized Aluminum Oxide Template with Assembly Structure

1 "... (111) Anodized Aluminum Oxide Template with Assembly Structure

10,10 ', 10 "... substrate of aluminum material

12,12 ', 12 "... electropolishing

14,14 ', 14 "... First Anodic Oxidation]

15,15 ', 15 "... anodized layer 16,16', 16" ... primary micropores

18,18 ', 18 "... dimples 20,20', 20" ... fine holes

30 .... Nickel (Ni) Nano Rod 32 .... Nickel Substrate

34 .... Nickel (Ni) Nano Metals

       The present invention relates to an anodized aluminum oxide (AAO) template used to fabricate nanorods, and more particularly, to have a (100) texture (crystal orientation), thereby reducing the precision of micropores filled with nano metals. It relates to an anodized aluminum template that has been improved to achieve excellent and uniform nanorods.

In the current electronic device industry, the miniaturization and high integration of devices are rapidly progressing, thereby increasing the need for nanoscale ultrafine patterns in the past micropatterns. Techniques for making such nanopatterns or nanostructures include E-Beam lithography, Scanning Tunneling Microscope (STM), and Atomic Force Microscope (AFM). Nano pattern or nano structure can be manufactured.

However, it has very expensive equipment and a lot of time-consuming disadvantages, so there are practical problems in making a large or large area of nano dots, nano wires and nano tubes.

Therefore, as an alternative to the typical electron beam transfer industry, large-area fixed-row nanostructures are fabricated and applied to not only basic research of nanomagnetics, but also nanometal magnetic lines with potential for application in radiation, magnetic sensing, and highly integrated magnetic circuits. For this purpose, it is important to achieve an economical and efficient high alignment arrangement.

To date, the industry has demonstrated that anodized aluminum oxide (AAO) templates, known to be physically and chemically stable, have a high degree of processing power to produce low cost, high yield, large area nanorods and nanowire arrays.

The technology for manufacturing such a nanostructure is largely divided into a top-down method and a bottom-up method. Nano-fabrication is being made using top-down techniques such as Electron-Beam Lithography, Scanning Tunneling Microscope, and Atomic Force Microscope. While research is underway, this approach is expensive and limited in productivity, and lithographic techniques for producing commercially available nanostructures below 50nm are still unrealized.

On the other hand, the bottom-up method is low in cost and high in productivity, but most of them are still in the research stage because they are not able to freely manufacture desired nanostructures.

On the other hand, the bottom-up technique is a nano template (nanotemplate) technology, which produces a mold with nanometer precision, and put the desired material in the fabricated nanodot (nanodot), nanowire (nanowire) And nanostructures such as nanotubes.

Therefore, nano-template technology is interconnected with many other technologies, and the production of nano-structures based on nano-templates has attracted much attention in the field of nanotechnology.

Aluminum (Al), which is used as a material of the nano template, is present in nature in a state of being covered with an oxide film because of its high oxygen affinity, and the aluminum oxide film has a high resistance to corrosion. The aluminum-based nano-template forms an anodized aluminum oxide film on one side, and is named as an anodic aluminum oxide template, and has been established as one of the representative nano-template technologies.

In addition, since such anodized aluminum template can be used to fabricate various nanostructures having a very large aspect ratio, which is difficult to achieve with current lithography technology, related researches are being actively conducted in various fields. In the anodized aluminum template as described above, a plurality of nano-sized micropores may be formed on one side thereof, and a nickel nano rod may be manufactured by filling a metal such as nickel (Ni) in the micropores.

However, such an anodized aluminum template should be uniformly formed in the diameter and length of the micropores in which the nanometals are filled to ensure uniformity of the resulting nanometals by uniformly filling the metal into the micropores. Therefore, in order to obtain nano metals with uniform physical properties, it is essential that the physical characteristics of the micropores formed in the anodized aluminum template should be uniform.

On the other hand, in the anodized aluminum template, the precision of micropores generated in the anodic oxide layer 15 (AAO layer) is changed according to various experimental variables. Factors affecting the precision of the micropores are variously influenced such as voltage, temperature during anodization, type of etching solution, purity of aluminum, and texture of aluminum (crystal orientation).

In particular, the size precision of the micropores among them is greatly affected by the aluminum texture, which has not been studied in the art so far.

The present invention is to solve the above-mentioned conventional problems, the object of the present invention is to provide an excellent precision of the size (dimension) of fine pores in the assembly of aluminum material affecting the shape of the planar micropores and the degree of alignment of the cross-sectional micropores It is to provide an anodized aluminum oxide template improved to have.

In another aspect, the present invention provides an improved anodized aluminum template to obtain a uniform and excellent quality nano-rod finally by having an excellent fine hole (dimension) dimension precision.

In order to achieve the above object, the present invention, in the anodized aluminum oxide template used to fabricate nanostructures,

A substrate of aluminum material;

An anodization layer formed on one side of the substrate; And

And a plurality of nano-sized micropores formed in the anodic oxidation layer.

The substrate provides an anodized aluminum template, characterized in that it has a (100) texture.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

The anodized aluminum template 1 according to the present invention has an excellent precision of the size of micropores, and has a substrate 10 of aluminum material, as shown in FIG. 1, and one side of the substrate 10. An anodization layer 15 is formed, and a plurality of nano-sized micropores 20 are formed in the anodization layer 15.

And this invention is a structure in which the said aluminum substrate 10 has (100) aggregate structure (crystal orientation).

In this way, the anodized aluminum oxide template 1 of the present invention, in which the aluminum substrate 10 has a (100) aggregate structure (crystal orientation), has another aggregate structure, for example, (110) aggregate, as shown in FIG. The planar roundness of the micropores 20 formed in the anodic oxide layer 15 is much higher than that of the anodized aluminum template 1 'having the structure and the anodized aluminum template 1 "having the (111) texture. will be.

In order to explain the effect of the present invention in more detail, a series of tests were conducted as follows.

The samples used in the present invention used commercially available aluminum substrates 10, 10 ', 10 "having a diameter of 20 mm and a thickness of 2 mm, and three different textures of (100), (110), and (111). It was to have.

As described above, anodized aluminum templates 1 were manufactured using aluminum single crystal substrates 10, 10 ', and 10 ", each having different textures. Observed.

Hereinafter, anodized aluminum template (1) (1 ') (1 "using aluminum single crystal substrates 10, 10', 10" having three textures of (100), (110), and (111). Will be described and the micropore 20, 20 'and 20 " observation results.

In the present invention, a common manufacturing process was used for the (100), (110), and (111) anodized aluminum oxide templates (1) (1 ') (1 "), and the manufacturing process is shown in FIG. It is shown as shown.

Prior to anodizing each of the aluminum single crystal substrates 10, 10 ′, 10 ″, the present invention was ultrasonically washed with acetone for 10 minutes to remove surface debris, phosphoric acid: chromic acid: ultrapure water (7: 2). : 1) delivery was polished (electropolishing) (12) (12 ') (12 ") with the addition of 35g / liter CrO ₃ in a mixed solution of a solution in a ratio of (see Fig. 3a).

The electropolishing (12) (12 ') (12 ") conditions were carried out for 5 to 15 minutes by applying a current of 3 ~ 10A at an electrolyte temperature of 50 ~ 80 ℃.

Electropolishing is the electrical polishing of aluminum in an acid solution. When aluminum is oxidized in an acid solution, oxygen and aluminum combine to form a film of alumina (Al ₂ O ₃ ) on the surface. This process is called anodic oxidation because aluminum where oxidation occurs is used as positive electrode. The alumina film thus formed is corroded by an acid solution to cause etching. If the etching rate is faster than the rate of anodization, the surface of aluminum is polished.

This phenomenon is called electropolishing, which has a very important meaning as a pretreatment process for making the anodized aluminum template 1. During the oxidation of alumina, the etching proceeds perpendicular to the equipotential line, so the direction of the micropores 20, 20 ', and 20 "becomes parallel only after anodizing, starting from a flat surface. Because.

After such electropolishing, each of the aluminum single crystal substrates 10, 10 ', 10 " was subjected to primary anodic oxidation 14, 14', 14 " (see Fig. 3B).

The aluminum single crystal substrates 10, 10 'and 10 " were processed in an anodizing apparatus, and 0.3 mol% oxalic acid solution was used as the electrolyte used for the anodic oxidation. Under the conditions, electrolyte solution temperature was 0-5 degreeC, and time was produced for 5 to 15 minutes.

In the initial stages of such primary anodic oxidation 14, 14 ′, 14 ″, primary micropores 16, 16 ′, 16 ″ are formed perpendicularly to the surface of alumina, although primary micropores are formed. The arrangement of (16) (16 ') (16 ") showed irregular characteristics. However, due to stress as the volume increases as aluminum turns to alumina, these primary micropores (16) (16 ') (16 ") are arranged by self-ordering in a form that minimizes stress.

At this time, since the arrangement that can utilize the given space most efficiently is hexagonal close-packing structure, the primary micropores 16, 16 ', 16 "are arranged in a hexagon, and consequently, honeycomb ( Hexagonal structures, such as honeycomb), were formed so that the primary micropores 16, 16 ', 16 "of the sample subjected to the first anodic oxidation process were cross-sectional, as shown in Figure 3b). Seen irregularly arranged.

Meanwhile, the aluminum single crystal substrates 10, 10 ′, 10 ″ which have undergone the first anodic oxidation process as described above have a regular arrangement at the interface between aluminum and alumina. As needed, the alumina layer formed by primary anodic oxidation (14) (14 ') (14 ") was chemically dissolved in the acid solution and removed.

Such a structure is shown in FIG. 3C, whereby the aluminum single crystal substrates 10, 10 ′, 10 ″ are alumina with regular arrangement of dimples 18, 18 ′, 18 ″. The surface was formed.

Next, in the present invention, the anodic oxidation layer 15 is subjected to secondary anodization on the surface of the alumina in which dimples 18, 18 ', 18 "are regularly arranged under the same conditions as the above primary anodization conditions. Micropores 20, 20 ', and 20 "regularly arranged in (15') and 15" were formed. Initially obtained from anodization layers 15, 15 'and 15 ". The size of the micropores 20, 20 ′ and 20 ″ was generated with a diameter of 30-40 nm (see FIG. 3D).

In the present invention, in order to expand the size of the micropores 20, 20 ', 20 ", the process of expanding the micropores 20, 20', 20" was performed. This was etched without applying electricity to the anodic oxide layers 15, 15 'and 15 "which formed initial micropores 20, 20' and 20" having a diameter of 30 to 40 nm as described above. . When the etching process is performed without electricity in this way, the inside of the micropores 20, 20 ', 20 "is evenly cut out, and the depths of the micropores 20, 20', 20" and their depths are reduced. The diameter of the micropores 20, 20 ′, 20 ″ may be made large while maintaining the gap therebetween as the first time.

Accordingly, in the present invention, the first micropores 16, 16 'and 16 "having a diameter of 30 to 40 nm are subjected to the micropore 20 and 20 having a diameter of 80 to 100 nm through such a pole widening. ')' To 20 &quot; (see FIG. 3E).

In the micropore expansion process, primary micropores 16, 16 'and 16 "were expanded for 50 minutes using 6.0 wt% H ₃ PO ₄ + 1.8 wt% CrO ₃ solution maintained at 20 ° C. This is shown by a planar and cross-sectional view in FIGS. 4a) and b) where a plurality of 80-100 nm micropores 20, 20 ′, 20 ″ are formed from the anodic oxidation layer of the anodized aluminum template 1. 15) (15 ') and 15 ". One of the anodized aluminum oxide templates thus anodized was photographed by FE-SEM.

In this micropore expansion process, the micropores 20, 20 ′ and 20 ″ can be seen that their diameters are constantly expanded over time, and this process is shown graphically in FIG. 5A). In addition, as the diameters of the micropores 20, 20 ′, 20 ″ were expanded, the thickness of the anodized aluminum oxide template 1, 1 ′, 1 ″ also increased as shown in FIG. 5B).

Through such a graph, in the present invention, anodized aluminum oxide templates (1) (1 ') (1 ") having sizes of micropores (20, 20', 20") having a diameter of 80 to 100 nm (100), ( Aluminum single crystal substrates 10, 10 'and 10 " having three textures of 110 and 111 were fabricated.

In Figs. 6A, 6B and 6C, XRD patterns of anodized aluminum oxide templates (1) (1 ') (1 ") having aluminum single crystals of (100), (110) and (111) textures, respectively, are shown. It is shown differently.

Such anodized aluminum oxide templates (1) (1 ') (1 ") of the (100), (110) and (111) textures are anodes as shown in a), b), c) of FIG. Different planar roundness of the micropores 20, 20 ', 20 "formed in the oxide layers 15, 15', 15" were obtained.

Of these (100), (110), and (111) anodized aluminum oxide templates (1) (1 ') (1 "), the anodized aluminum oxide template (1) of the (100) texture is the planar fine. The shape and cross-sectional alignment of the balls 20 also proved to be the best in terms of aspect.

FIG. 7 shows a nickel (Ni) nanorod 30 fabricated using the anodized aluminum template 1 of the (100) texture according to the present invention.

Such nickel (Ni) nanorods 30 are electroplated with nickel metal to fill the micropores 20, 20 ′, 20 ″ of the anodized aluminum oxide template 1, and then the nickel nanorods 30 are filled. For observation, the anodized aluminum template 1 was removed by etching.

The nickel (Ni) nanorods 30 manufactured as described above were observed to have grown on the nickel substrate 32 with nickel (Ni) nano metals 34 of uniform size.

Therefore, it was confirmed that the use of the anodized aluminum oxide template (1) of the (100) texture obtained by the present invention enables obtaining the nickel (Ni) nanorods 30 having excellent uniformity in terms of diameter and length.

Although the present invention has been described in detail with reference to the accompanying drawings, the present invention is not limited to such a specific structure. Those skilled in the art may variously modify or change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. Nevertheless, it will be apparent that all such modifications or variations will fall within the scope of the present invention.

As described above, according to the present invention, the shape of the planar micropores and the alignment of the cross-sectional micropores are better than those of the other anodized aluminum templates of the (110) and (111) textures. To have.

Therefore, by using the anodized aluminum oxide template of the (100) texture according to the present invention it is possible to obtain a nanorod with excellent uniformity in terms of diameter and length.

Claims (1)

Anodized aluminum oxide template used to fabricate nanostructures, A substrate of aluminum material; An anodization layer formed on one side of the substrate; And And a plurality of nano-sized micropores formed in the anodic oxidation layer. And the substrate has a (100) texture.

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