TWI759950B - Method for making metal compound nanotubes - Google Patents

Abstract

A method for manufacturing a metal compound nanotube, which comprises depositing a metal seed layer with a thickness of 10 nm to 100 nm on a substrate, and then depositing an aluminum layer on the metal seed layer, and the metal seed layer and the aluminum The materials of the layers are different. Next, an anodized aluminum template having a plurality of holes for exposing the metal seed layer is formed on the aluminum layer by anodizing method, and the metal seed layer is grown into metal in the holes by anodizing method. oxide nanotubes, followed by removal of the anodized aluminum template to form the metal oxide nanotubes on the substrate. Finally, while the metal oxide nanotubes are annealed, a substance is vaporized to replace the oxygen element of each metal oxide nanotube, so that the metal oxide nanotubes form a plurality of metal compounds nanotubes.

Description

Method for making metal compound nanotubes

The present invention relates to a method for fabricating nanotubes, in particular to a method for fabricating metal compound nanotubes.

Tungsten trioxide is a transition metal oxide semiconductor material with narrow energy band width (2.6~3.0 eV), good photocatalytic properties in the visible light range, and tungsten atoms have different oxidation states (commonly W ⁴⁺ , W ⁵⁺ and W ⁶⁺ ), which make it have broad application prospects in the fields of gas sensing and electrochromic.

At present, tungsten trioxide nanopillars are often formed through anodized aluminum oxide (AAO) nanotemplates for subsequent applications such as gas sensor elements. However, there are many tungsten trioxide grown in this way. Nanopillars have poor specific surface area.

Therefore, the purpose of the present invention is to provide a method for manufacturing metal compound nanotubes.

Therefore, the manufacturing method of the metal compound nanotube of the present invention deposits a metal seed crystal layer with a thickness of 10 nm-100 nm on a substrate in advance, and then deposits an aluminum layer on the metal seed crystal layer, and the metal seed crystal layer Different from the material of the aluminum layer.

Next, an anodized aluminum template having a plurality of holes for exposing the metal seed layer is formed on the aluminum layer by anodizing method, and the metal seed layer is grown into metal in the holes by anodizing method. oxide nanotubes.

The anodized aluminum template is then removed to form the metal oxide nanotubes on the substrate, and finally, while the metal oxide nanotubes are annealed, a substance is vaporized to replace each of the metal Oxygen element of the oxide nanotubes, so that the metal oxide nanotubes form a plurality of metal compound nanotubes.

The effect of the present invention lies in that by controlling the thickness of the metal seed layer to be between 10 nm and 100 nm and matching with an anodized aluminum oxide template, a plurality of metal oxide nanotubes can be grown, and the nanotube structure can increase the ratio of components. surface area, which has better performance in applications such as gas sensing or hydrogen production electrodes. In addition, at the same time of subsequent annealing, a substance is vaporized to replace the oxygen element in each of the metal oxide nanotubes, so that the The metal oxide nanotubes form a plurality of metal compound nanotubes, and the desired metal compound nanotubes can be prepared according to this simple process.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are designated by the same reference numerals.

Referring to FIG. 1 and FIG. 2 , the fabrication method of the metal compound nanotube of the present invention includes a providing step, a forming step, and a post-processing step.

The providing step is to provide a substrate unit 2 . The substrate unit 2 includes a substrate 21, a metal seed layer 22 disposed on the surface of the substrate 21, and an aluminum layer 23 disposed on the metal seed layer 22; wherein, the metal seed layer 22 and the aluminum The material of layer 23 is different.

The substrate 21 suitable for this embodiment is not particularly limited, and a conductive substrate can be directly selected or a conductive layer made of conductive material is formed on the surface of an insulating substrate to constitute the substrate 21. In this embodiment, the substrate 21 is Taking silicon substrate as an example for illustration; and the metal seed layer 22 is selected from tungsten (W) metal, but not limited to this, and can also be titanium (Ti), niobium (Nb), or tantalum (Ta) and other metals.

Specifically, the substrate unit 2 provided in the providing step is formed by sequentially depositing the metal seed layer 22 and the aluminum layer 23 on the substrate 21 by physical vapor deposition such as sputtering or vapor deposition. Preferably, in the present embodiment, the metal seed layer 22 is formed by depositing tungsten metal with a thickness of 10 nm-100 nm on the substrate 21 by electron beam (E-beam) evaporation. Then, the aluminum layer 23 is deposited on the metal seed layer 22 by a thermal coater method to complete the substrate unit 2 . It should be noted that the formation methods of the metal seed layer 22 and the aluminum layer 23 are not particularly limited. In addition to the physical vapor deposition method described in this embodiment, chemical vapor deposition methods can also be used, or Others can be as long as the metal seed layer 22 and the aluminum layer 23 can be sequentially disposed on the substrate 21 .

After the providing step is completed, the forming step is followed by forming an anodized aluminum layer 23 with a plurality of holes 230 through which the metal seed layer 22 can be exposed by anodization. oxide, AAO) template 231.

Specifically, the manufacturing method of the anodic aluminum oxide (AAO) template 231 is mainly to immerse the aluminum layer 23 in an acid solution, and perform anodization treatment, so that the aluminum layer 23 undergoes an electrochemical etching reaction, so that the aluminum layer 23 is subjected to an electrochemical etching reaction. Layer 23 is oxidized to the anodic aluminum oxide (AAO) template 231 with nanometer-sized pores 230 .

After the anodized aluminum template 231 is formed, the metal seed layer 22 is continuously grown into the metal oxide nanotubes 24 in the holes 230 by anodization. It should be noted that, in this embodiment, the metal seed layer 22 is made of tungsten (W) metal, and the thickness of the tungsten metal is controlled to be between 10 nm and 100 nm. Therefore, when a voltage is applied by anodization method , tungsten trioxide (WO ₃ ) nanotubes can be formed in the nano-sized holes 230; wherein, the size of the applied voltage can be further adjusted according to the application to control the diameter of the tungsten trioxide nanotubes , and by adjusting the thickness of the metal seed layer 22 to adjust the height of the tungsten trioxide nanotubes, in addition, the arrangement of the tungsten trioxide nanotubes can pass through the anodic aluminum oxide (AAO) template 231 respectively. Wait for hole 230 to adjust. Referring to FIG. 3 , FIG. 3 is an SEM image showing the formation of the metal oxide nanotubes 24 on the anodized aluminum template 231 .

In the present embodiment, the forming of the anodized aluminum template 231 and the growth of the metal oxide nanotubes 24 are continuously performed under the same anodizing treatment conditions. In other words, in this embodiment, the The substrate unit 2 with the metal seed layer 22 and the aluminum layer 23 is placed in the acidic solution, and a voltage is continuously applied in the acidic solution, so that the aluminum layer 23 gradually forms the anodized aluminum template, the The metal seed layer 22 can also be grown directly into the metal oxide nanotubes 24 in the holes 230 . In this embodiment, an oxalic acid solution with a concentration of 0.3M is used as the acidic liquid, the temperature of the solution is controlled to be between 4°C and 25°C, and the applied voltage is 10V to 130V. The principle is well known to those skilled in the art and will not be described in detail here.

After the metal oxide nanotubes 24 are formed in the holes 230, the anodized aluminum template 231 can be removed to expose the metal oxide nanotubes 24 on the substrate 21 to form A nanotube coupon 3. In this embodiment, the anodized aluminum template 231 is immersed in a phosphoric acid solution with a concentration of 6 wt %, and the temperature is maintained at about 60° C. for 8 minutes, so that the anodized aluminum template 231 can be removed. It should be noted that an alkaline solution such as sodium hydroxide (NaOH) can also be used to remove the anodized aluminum template 231 , as long as the metal oxide nanotubes 24 are not damaged.

In this embodiment, the metal oxide nanotubes 24 spaced apart from each other are grown by controlling the thickness of the metal seed layer 22 and matching with the anodized aluminum oxide template 231 to increase the specific surface area of the device through the nanotube structure. Further, the application performance of the element is improved, and preferably, in order to further increase different applications, in this embodiment, the post-processing step is also implemented after the forming step.

Referring to FIG. 4 , in the post-processing step, the nanotube test piece 3 is placed in an annealing apparatus 4 to perform high temperature annealing on the metal oxide nanotubes 24 , and a substance 30 is annealed at the same time as the annealing. Vaporization replaces the oxygen element of each of the metal oxide nanotubes 24 to allow the metal oxide nanotubes 24 to form a plurality of metal compound nanotubes.

Specifically, in this embodiment, the substance 30 can be selected from chalcogenides such as sulfur, selenium, or tellurium. Therefore, in the post-processing step, annealing at a high temperature of 300° C. to 800° C. is used to anneal sulfur and selenium. , or chalcogenides such as tellurium are vaporized, and these tungsten trioxide nanotubes are subjected to sulfurization, selenization, or tellurization to form a plurality of tungsten disulfide (WS ₂ ) nanotubes, a plurality of diselenide nanotubes, respectively. Tungsten carbide (WSe ₂ ) nanotubes, or multiple tungsten ditelluride (WTe ₂ ) nanotubes. It should be noted that the temperature for vaporizing the substance 30 can be adjusted according to the type of the substance 30 . For example, when vaporizing sulfur, the operating temperature can be higher than 300°C, and when vaporizing selenium, the temperature must be increased When the temperature reaches 400°C, enough energy can be provided for selenium to replace oxygen in tungsten trioxide. However, when the temperature is higher than 800°C, tungsten trioxide is prone to grain growth and affects the shape of nanotubes.

Referring to FIG. 5 , FIG. 5 illustrates the post-treatment of growing tungsten trioxide nanotubes using an anodized aluminum template 231 and using sulfur as the substance 30 to vulcanize these tungsten trioxide nanotubes as an example. , it can be seen from the Raman spectrum measurement analysis in Figure 5 that the signal of tungsten disulfide can be detected after the annealing temperature is greater than 400 ℃, and as the temperature of the working environment increases, the disulfide disulfide can be detected. The tungsten signal is also stronger.

In this embodiment, by further performing the post-processing step, at the same time of subsequent annealing, sulfur is used as the substance 30 to replace the oxygen element of the tungsten trioxide nanotubes, so that the tungsten trioxide nanotubes are vulcanized to form many A tungsten disulfide (WS ₂ ) nanotube, the tungsten disulfide has better hydrogen production effect, and can have better performance in subsequent applications such as gas sensing or hydrogen production electrodes.

To sum up, in the method for fabricating metal compound nanotubes of the present invention, by controlling the thickness of the metal seed layer 22 (W) to be between 10 nm and 100 nm, and matching with the anodic aluminum oxide template 231 (AAO), it is possible to grow more A metal oxide nanotube 24 (WO ₃ nanotubes), the nanotube structure can increase the specific surface area of the device, and it has better performance in applications such as gas sensing or hydrogen production electrodes. At the same time, a substance is vaporized to replace the oxygen element of each of the metal oxide nanotubes, so that the metal oxide nanotubes 24 can form a plurality of metal compound nanotubes, and the desired metal can be prepared according to the application. The compound nanotube can indeed achieve the purpose of the present invention.

However, the above are only examples of the present invention, and should not limit the scope of implementation of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the patent specification are still included in the scope of the present invention. within the scope of the invention patent.

2: Substrate unit

21: Substrate

22: Metal seed layer

23: Aluminum layer

230: Hole

231: Anodized Aluminum Template

24: Metal oxide nanotubes

3: Nanotube test piece

30: Substance

4: Annealing device

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: 1 is a schematic diagram of a fabrication process, illustrating a provision step in an embodiment of a fabrication method of a metal compound nanotube of the present invention; FIG. 2 is a schematic diagram of a manufacturing process, illustrating a forming step in this embodiment of the present invention; 3 is a scanning electron microscope (SEM) image, illustrating an SEM image of an anodized aluminum template and a plurality of metal oxide nanotubes in the forming step; FIG. 4 is a schematic diagram illustrating a post-processing step in this embodiment of the present invention; and FIG. 5 is a Raman spectrogram illustrating the Raman spectrogram of the nanotube test piece of this embodiment at different annealing temperatures.

21: Substrate

22: Metal seed layer

23: Aluminum layer

230: Hole

231: Anodized Aluminum Template

24: Metal oxide nanotubes

3: Nanotube test piece

Claims (8)

A method for fabricating a metal compound nanotube, comprising: depositing a metal seed layer with a thickness of 10 nm to 100 nm on a substrate; depositing an aluminum layer on the metal seed layer, and the metal seed layer and the metal seed layer The material of the aluminum layer is different; an anodized aluminum template with a plurality of holes that can expose the metal seed layer is formed on the aluminum layer by anodizing method; the metal seed layer is formed in the holes by anodizing method growing into metal oxide nanotubes; removing the anodized aluminum template to form the metal oxide nanotubes on the substrate; and annealing the metal oxide nanotubes while annealing a selected The substance from the chalcogenide vaporizes to replace the oxygen element of each of the metal oxide nanotubes, so that the metal oxide nanotubes form a plurality of metal chalcogenide nanotubes. The method for fabricating metal compound nanotubes as claimed in claim 1, wherein the metal seed layer is selected from tungsten, so that the metal chalcogenide nanotubes form a plurality of tungsten chalcogenide nanotubes. The method for fabricating metal compound nanotubes as claimed in claim 1, wherein the chalcogenide is selected from sulfur, selenium, or tellurium, so that these metal oxide nanotubes are respectively formed into a plurality of tungsten disulfide nanotubes , a plurality of tungsten diselenide nanotubes, or a plurality of tungsten ditelluride nanotubes. The method for producing a metal compound nanotube according to claim 1, wherein, The annealing temperature is between 300°C and 800°C. The method for fabricating metal compound nanotubes as claimed in claim 1, wherein the removal of the anodized aluminum template is performed by immersing it in an acidic solution or an alkaline solution. The method for fabricating metal compound nanotubes according to claim 1, wherein the substrate is selected from silicon substrates. The method for fabricating metal compound nanotubes as claimed in claim 1, wherein the metal seed layer and the aluminum layer are sequentially deposited on the substrate by a physical vapor deposition method. The method for fabricating metal compound nanotubes as claimed in claim 7, wherein the metal seed layer and the aluminum layer are deposited by sputtering or evaporation.

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