KR20190023384A - Synthesis of Silica Nanowires Using Amorphous Silicon - Google Patents

Abstract

The present invention provides a method for manufacturing silica nanowires using amorphous silicon and silica nanowires manufactured from the same. The method for manufacturing silica nanowires using amorphous silicon comprises steps of: (a) depositing an amorphous silicon thin layer on a substrate placed in a reactor by performing a plasma enhanced chemical vapor deposition (PECVD) method; (b) forming a metal thin film layer on the substrate on which the thin film layer is deposited through the step (a) by performing a vacuum deposition method; and (c) heat-treating the metal thin film layer deposited on the substrate through the step (b) with metal atoms of the metal thin film layer as a catalyst to form silica nanowires. An object of the present invention is to provide a manufacturing method capable of forming a large amount of silica nanowires at low cost by replacing expensive silicon wafers.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a silica nanowire using amorphous silicon,

The present invention relates to a method for producing silica nanowires using amorphous silicon.

Silica nanowires are excellent in luminescence and foreign matter adsorption, and are nanomaterials that can be used in various photoelectric elements such as micro waveguides, light emitting diodes, and biosensors.

Due to the high applicability of silica nanowires, various studies have been conducted to produce them. Recently, a method for manufacturing silica nanowires using a metal catalyst has attracted much attention.

As an example of a method for producing the silica nanowire using such a metal catalyst, a metal thin film for catalyst is deposited on a crystalline silicon wafer, and then, in an atmosphere of argon (Ar) or nitrogen (N ₂ ) gas containing a small amount of oxygen, (Hereinafter, referred to as " Prior Art 1 ") for producing silica nanowires by heat treatment is generally known.

As a part of a study on a method for producing silica nanowires using the metal catalyst described above, Korean Patent Publication No. 10-2015-0053140 filed on Mar. 11, 2013, published on May 15, 2015, A technique for manufacturing a silica nanowire composite in which silica nanowires are grown on a silicon wafer and a silane group is introduced on the surface of the silica nanowires has been proposed.

The prior art 1 and the prior art 2 use silicon as a precursor for forming silica nanowires from silicon wafers and silicon as a base material for providing silicon (Si) among oxygen (O) However, the use of such a silicon wafer has a high manufacturing cost because of the high cost of the wafer itself.

In addition, since the use of a silicon wafer in manufacturing a silica nanowire uses only a part of a surface layer of a silicon wafer, there is a problem that a large amount of base material is wasted and mass production is difficult due to limitation of the area, This is a fundamental limitation.

Therefore, there is a need for a technique for manufacturing a large amount of silica nanowires at low cost.

An object of the present invention is to provide a manufacturing method capable of forming a large amount of silica nanowires at low cost by replacing expensive silicon wafers.

In order to achieve the above object, a method for manufacturing a silica nanowire using amorphous silicon according to an embodiment of the present invention includes the steps of: (a) performing a plasma enhanced chemical vapor deposition (PECVD) Depositing an amorphous silicon thin film layer on the substrate; (b) forming a metal thin film layer by performing a vacuum deposition method on the substrate on which the amorphous silicon thin film layer is deposited through the step (a); And (c) heat-treating the substrate on which the metal thin film layer is deposited through the step (b) to form silica nanowires with metal atoms of the metal thin film layer as catalysts. At this time, the amorphous silicon thin film layer is a source of silicon (Si) reacting with metal atoms of the metal thin film layer to form silica nanowires.

A step of forming a buffer layer on the substrate may be preceded by the step (a), and the buffer layer may be a silicon dioxide (SiO ₂ ) thin film layer.

Further, the step (a) in carrying out a plasma chemical vapor deposition method can be used with 5% four days alkylene (SiH ₄₎ diluted with nitrogen gas into the reaction gas.

In the step (b), the metal thin film layer may be made of nickel (Ni).

In the step (c), the substrate on which the amorphous silicon thin film layer and the metal thin film layer are deposited under a nitrogen gas containing oxygen may be heat-treated.

On the other hand, silica nanowires can be manufactured by the above-described method for producing silica nanowires using amorphous silicon.

Here, the silica nanowire is amorphous silica composed of SiOx, and x may be 0 < x < 3.

Then, a photoelectric device can be manufactured using a silica nanowire.

As described above, the present invention has the following effects.

First, silica nanowires fabricated using amorphous silicon have almost no difference from the case of using crystalline silicon wafers in all aspects, such as the microstructure and physical characteristics of silica nanowires including the formation mechanism, so that silica nanowires are manufactured It is possible to use an amorphous silicon thin film instead of a conventional crystalline silicon wafer.

Second, the present invention because it can be produced by plasma chemical vapor deposition (PECVD) of 5% four days alkylene (SiH ₄₎ supplies the gas is diluted by the method of nitrogen in the process of depositing an amorphous silicon thin film on an arbitrary substrate, a high-priced the pure four days alkylene (SiH ₄₎ prior art, reduce the amount of the gas can be the production cost savings compared to conventional crystalline silicon wafer is expensive, and this time, the amorphous silicon thin film layer can be manufactured in a large area with a limitation of the area It is also possible to produce a larger amount of silica nanowires than the crystalline silicon wafers of the present invention. That is, the use of the amorphous silicon thin film makes it possible to manufacture a large amount of silica nanowires at a low manufacturing cost as compared with the production of the silica nanowires using a conventional crystalline wafer.

Third, the manufacturing cost of the photoelectric device manufactured using the silica nanowire manufactured by the method of manufacturing the silica nanowire using the amorphous silicon of the present invention can be reduced.

1 is a flowchart illustrating a method of manufacturing a silica nanowire using amorphous silicon according to an embodiment of the present invention.
FIG. 2 is a schematic view schematically illustrating a method for manufacturing silica nanowires using amorphous silicon according to an embodiment of the present invention. Referring to FIG.
FIG. 3 is a schematic view schematically illustrating a method of manufacturing silica nanowires using amorphous silicon according to an embodiment of the present invention. Referring to FIG.
4 is a scanning electron microscope (SEM) photograph of a silicon wafer (a) coated with a nickel thin film layer and (b) a substrate on which an amorphous silicon thin film layer is deposited, after annealing at 1100 ° C for 1 hour.
5 is a scanning electron microscope (SEM) image of a silicon wafer and (b) a substrate on which an amorphous silicon thin film layer is deposited, after annealing the substrate at 1100 ° C for 1 hour and measuring the surface covered with the nanowire.
FIG. 6 is a photograph showing a high magnification transmission microscope (HRTEM) photograph and (b) an electron diffraction (ED) pattern of the silica nanowire prepared according to the method for producing silica nanowires using amorphous silicon according to an embodiment of the present invention. It is.
FIG. 7 is a graph showing an X-ray spectroscopy (EDX) spectrum of silica nanowires prepared according to the method for producing silica nanowires using amorphous silicon according to an embodiment of the present invention.
FIG. 8 is a graph showing a photoluminescence spectrum of a silica nanowire fabricated according to a method of manufacturing silica nanowires using amorphous silicon according to an embodiment of the present invention. Referring to FIG.

The preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which the technical parts already known will be omitted or compressed for simplicity of explanation.

FIG. 1 is a flowchart illustrating a method of manufacturing a silica nanowire using amorphous silicon according to an embodiment of the present invention. FIG. 2 is a schematic view illustrating a method of manufacturing a silica nanowire using amorphous silicon according to an embodiment of the present invention. And FIG. 3 is a schematic view schematically showing a method of manufacturing silica nanowires using amorphous silicon according to an embodiment of the present invention.

Referring to FIGS. 1 to 3, a method for fabricating silica nanowires using amorphous silicon according to an embodiment of the present invention may include the following steps of depositing an amorphous silicon thin film layer.

1. (a) Step < S100 >

(a) step S100 is a step of depositing an amorphous silicon thin film layer 2 on a substrate 1 placed in a reactor by performing a plasma-enhanced chemical vapor deposition (PECVD) method. In step (a), the amorphous silicon thin film layer 2 is formed on the substrate 1 by using 5% SiH ₄ gas diluted with nitrogen as a reactive gas in the plasma chemical vapor deposition (CVD) Lt; / RTI &gt; At this time, the above-mentioned reaction gas is meant to be a 5% four days alkylene (SiH ₄₎ including the ratio of nitrogen gas to the total flow rate of the mixed gas that contains nitrogen and four days alkylene (SiH ₄₎ gas. The substrate 1 is not limited to glass, plastic, or the like, but may be any substrate capable of coating the amorphous silicon thin film layer 2.

The step (a) may be preceded by a step of forming a buffer layer (bl) on the substrate 1 before the step (S100), wherein the buffer layer (bl) may be a silicon dioxide (SiO ₂ ) thin film layer. Here, the step of forming the buffer layer &quot; bl &quot; can be performed when it is necessary to prevent the specific component of the substrate 1 from affecting nanowire growth. However, when the substrate 1 is a glass substrate, since the buffer layer (bl) is a component like glass, the step of forming the buffer layer (bl) can be omitted.

At this time, the amorphous silicon thin film layer 2 deposited on the substrate 1 in step (a) provides silicon (Si) as a precursor element forming the silica nanowire and silicon (Si) as oxygen Based materials. That is, the amorphous silicon thin film layer 2 is a source of silicon (Si) reacting with metal atoms of the metal thin film layer 3 to be described later to form the silica nanowires 4.

Here, the amorphous silicon thin film layer 2 is formed by supplying 5% SiH ₄ gas diluted with nitrogen in the process of depositing the amorphous silicon thin film layer 2 on an arbitrary substrate through plasma chemical vapor deposition (PECVD) itgie to be prepared, the manufacturing cost can be reduced and expensive four days pure alkylene (SiH _4), reducing the amount of the gas. In addition, (a) the amorphous silicon thin film layer 2 can be manufactured in a large area in step (S100), and it is possible to manufacture a larger amount of silica nanowires than conventional crystalline silicon wafers having area limitation.

That is, since the amorphous silicon thin film layer 2 uses only a part of the surface layer in manufacturing a large amount of silica nanowire at a low cost, the conventional crystalline silicon nanowire has a problem of large waste of the base material, It has characteristics of a base material suitable for a silicon wafer.

2. (b) In step < S200 >

(b) Step (S200) is a step of forming a metal thin film layer 3 by performing a vacuum deposition method on a substrate on which an amorphous silicon thin film layer is deposited through (a). At this time, the metal thin film layer 3 according to an embodiment of the present invention may be made of nickel (Ni).

Here, the metal atom of the metal thin film layer 3 acts as a metal catalyst reacting with silicon (Si) supplied from the amorphous silicon thin film layer 2 in the step (c) to be described later.

3. (c) Step < S300 >

(c) In step S300, the metal nanowire 4 is formed on the substrate on which the metal thin film layer 3 is deposited through the metal thin film layer 3 as a catalyst through the heat treatment step (b) .

In step S300, the substrate 1 on which the metal thin film layer 3, the amorphous silicon thin film layer 2, and the like are deposited is placed in a tubular heating furnace. The high purity nitrogen containing oxygen is fired Annealing at a temperature in the range of 800 ° C to 1200 ° C. More specifically, the heat treatment can be performed at a temperature of 1100 캜. At this time, the heat treatment can be performed at the eutectic temperature between the metal elements of the metal thin film layer 3 used as the catalyst, that is, the nickel (Ni) and silicon (Si).

At this time, (c) the oxygen supplied into the electric furnace in step S300 provides silicon (Si), which is a precursor element forming the silica nanowire, and oxygen (O), among oxygen (O).

The substrate 1 on which the metal thin film layer 3 and the amorphous silicon thin film layer 2 are deposited in the tubular heating furnace is formed of nickel (Ni) and silicon (Si) Ni is reacted with silicon (Si) in the amorphous silicon thin film layer 2 to form a Si-Ni eutectic liquid droplet in the case of performing the heat treatment at the eutectic point temperature of the amorphous silicon thin film layer 2. At this time, oxygen (O) supplied to the furnace during the heat treatment is absorbed by the eutectic liquid droplets, and SiO, which is fine particles forming the silica nanowires by the reaction of silicon (Si) and oxygen (O) So that the solid silica nanowires 4 are grown.

At this time, the silica nanowire (4) is amorphous silica composed of SiOx, and x may be 0 <x <3.

The silica nanowire 4 can be manufactured by the above-described method for producing silica nanowires using amorphous silicon, and the photoelectric device can be manufactured using the silica nanowire 4 thus produced.

In the meantime, the silica nanowires can be manufactured through the above-described manufacturing method, and examples and comparative examples will be described in order to facilitate understanding of the present invention and will be described with reference to FIGS. 4 to 8. FIG. However, the following embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to the following embodiments.

FIG. 4 is a scanning electron microscope (SEM) photograph of a silicon wafer coated with a nickel thin film layer and (b) an amorphous silicon thin film layer deposited thereon, annealed at 1100 ° C. for 1 hour, a scanning electron microscope (SEM) photograph of a silicon wafer and (b) a substrate on which an amorphous silicon thin film layer is deposited is annealed at 1100 캜 for 1 hour and then the surface covered with the nanowire is measured. 6 is a photograph showing a high-magnification transmission microscope (HRTEM) photograph of the silica nanowire prepared according to the method for producing silica nanowires using amorphous silicon according to an embodiment of the present invention and (b) an electron diffraction (ED) pattern FIG. 7 is a graph showing an X-ray spectroscopy (EDX) spectrum of a silica nanowire fabricated by a method for producing silica nanowires using amorphous silicon according to an embodiment of the present invention, FIG. 2 is a graph showing a photoluminescence spectrum of a silica nanowire fabricated according to a method of manufacturing a silica nanowire using amorphous silicon according to an embodiment of the present invention. FIG.

Example

First, an amorphous silicon (a-Si) thin film layer was deposited on a substrate by a plasma chemical vapor deposition (CVD) method under 5% SiH ₄ gas diluted with nitrogen. At this time, the substrate was a P-type silicon wafer coated with a silicon dioxide (SiO ₂ ) film as a buffer layer. The silicon dioxide (SiO ₂ ) film was used to block the effect of the crystalline silicon wafer (c-Si) when forming the silica nanowire, and its thickness was 650 nm. The amorphous silicon thin film deposited by the plasma chemical vapor deposition method was formed to have a thickness of 1 탆.

Then, a metal thin film layer having a thickness of about 20 nm is formed on the amorphous silicon thin film layer by a vacuum deposition method, that is, a nickel film is formed. Then, the sample 1 on which the nickel film is deposited is heat treated in a tubular heating electric furnace to form SiOx- Lt; / RTI &gt; At this time, the heat treatment was performed at 1100 占 폚 for 1 hour while clouding the high purity nitrogen containing about 2.0 ppm of oxygen.

Comparative Example

In this embodiment, when a metal thin film layer is formed on the amorphous silicon thin film layer, a metal thin film layer, that is, a nickel film having a thickness of about 20 nm is formed on a crystalline silicon (s-Si) wafer by a vacuum deposition method, The silica nanowires were grown on a silicon wafer by heat treatment in a tubular heating furnace. At this time, the heat treatment was performed at 1100 占 폚 for 1 hour while clouding the high purity nitrogen containing about 2.0 ppm of oxygen.

Examples Comparative example  comparison analysis

FIG. 4 is a side-view scanning electron microscope (SEM) photograph of the sample 1 and the comparative sample 2 after heat treatment at 1100 ° C. for 1 hour at the same time. It's a picture. 4 (a) is a photograph of the sample 2 of the comparative example, and Fig. 4 (b) is a photograph of the sample 1 of the example.

In this case, it can be confirmed that nanowires are formed on the substrate in both samples. As a result, it can be seen that the amorphous silicon (a-Si) thin film also has silica nanowires formed by using nickel (Ni) metal as a catalyst. 4 (a), the surface of the crystalline silicon (c-Si) wafer is ruggedly formed because the nickel of the metal thin film layer reacts with the silicon (Si) of the silicon wafer to form a Si-Ni eutectic liquid droplet to be. Hereinafter, the process of growing the silica nanowires has been described in detail.

4 (b), the surface of the silicon (c-Si) wafer used as the substrate under the silicon dioxide (SiO ₂ ) film remains smooth, Which means that the contained Si did not participate in the formation reaction process of the Si-Ni eutectic liquid droplets. On the other hand, on the silicon dioxide (SiO ₂ ) film, it is confirmed that a layer in which small nanowires are densely arranged in a pore pattern is formed at the position of the initial amorphous silicon (a-Si) thin film layer before the heat treatment. -Si) thin film layer all react with nickel (Ni) to grow into silica nanowires.

Fig. 5 shows a scanning electron microscope (SEM) photograph taken at the same magnification of the silica nanowires of Figs. 4 (a) and 4 (b). 5 (a) is a photograph of silica nanowire (sample 2) grown using a silicon wafer, and FIG. 5 (b) is a photograph of a silica nanowire (sample 1) grown using amorphous silicon.

Here, FIG. 5 shows that nanowires of long length are formed in both samples, and the thickness is also very uniform. From these results, it can be confirmed that silica nanowires having a sufficient length and a uniform thickness can be manufactured using amorphous silicon (a-Si) thin film as well as crystalline silicon (c-Si) wafers.

At this time, the thickness of the silica nanowire shown in Fig. 5 (b) is about 53 nm in average diameter. Here, the thickness of the silica nanowire may depend on the thickness of the amorphous silicon thin film layer. That is, as the thickness of the amorphous silicon thin film layer deposited on the substrate increases, the number of silicon (Si) atoms supplied in the heat treatment step increases, and the average diameter of the silica nanowires also increases.

FIGS. 6 to 7 illustrate the microstructure, chemical composition, and photoluminescence characteristics of the silica nanowires grown by the examples.

6 (a) and 6 (b) show a high magnification transmission microscope (HRTEM) photograph and an electron diffraction (ED) pattern for silica nanowires, respectively. Here, the photograph of FIG. 6 (a) shows that the silica nanowires prepared according to the example have a very smooth surface and do not contain any particles in the nanowires. These results indicate that the nanowires are formed in a homogeneous structure. From the photograph of FIG. 6 (b), the silica nanowire produced according to the example does not show the circular pattern formed by the bright points of regular arrangement indicating crystallinity or the bright points indicating polycrystallinity.

The results of FIGS. 6 (a) and 6 (b) are in good agreement with experimental results for conventional silica nanowires, which is a typical pattern observed on an amorphous phase. From these results, the silica nanowires formed by the amorphous silicon thin- It is judged as a substance.

Figure 7 shows an X-ray spectroscopy (EDX) spectrum performed to determine the chemical composition of the amorphous silica nanowire. The silica nanowires prepared according to the embodiments include silicon (Si), oxygen (O) and nickel (Ni), and in particular, silicon (Si) and oxygen (O), which are major chemical components of silica nanowires, The chemical composition ratios of the atoms are 30.2at.% And 68.9at.%, Respectively. At this time, the above composition ratio means atomic percent of atomic number. From these results, it can be confirmed that the silica nanowire prepared according to the embodiment is amorphous silica having a composition of SiO _{2 .3} .

FIG. 8 is a photoluminescence spectrum of the silica nanowire fabricated according to the embodiment. As shown in FIG. 4, the light emitted from the excitation light source is measured on the surface of the silica nanowire- .

8, it can be seen that the main emission wavelength of the silica nanowire fabricated according to the embodiment is about 430 nm, and the results are shown in FIG. 8, which shows that the silica nanowires grown from the crystalline silicon (c-Si) It is in good agreement with the photoluminescence emission characteristics of the silica nanowires.

The comparison of the above-described examples and comparative examples shows that the production of silica nanowires using amorphous silicon is superior to the case of using crystalline silicon wafers in all aspects including the microstructure and physical properties of the silica nanowires including the mechanism of formation of silica nanowires And there is almost no difference between them.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. And the scope of the present invention should be understood as the scope of the following claims and their equivalents.

1: substrate
2: Amorphous silicon thin film layer
3: metal thin layer
4: silica nanowire
bl: buffer layer

Claims (8)

(a) depositing an amorphous silicon thin film layer on a substrate placed in a reactor by performing a plasma-enhanced chemical vapor deposition (PECVD) method;
(b) forming a metal thin film layer by performing a vacuum deposition method on the substrate on which the amorphous silicon thin film layer is deposited through the step (a); And
(c) heat-treating the metal thin film layer deposited on the substrate using the metal atoms of the metal thin film layer as a catalyst to form silica nanowires through the step (b)
Wherein the amorphous silicon thin film layer is a source of silicon (Si) reacting with metal atoms of the metal thin film layer to form silica nanowires
Process for the preparation of silica nanowires using amorphous silicon.
The method according to claim 1,
The step of forming a buffer layer on the substrate is preceded by the step (a), and the buffer layer is a silicon dioxide (SiO ₂ ) thin film layer
Process for the preparation of silica nanowires using amorphous silicon.
The method according to claim 1,
In the step (a), 5% silane (SiH ₄ ) gas diluted with nitrogen is used as a reaction gas in the plasma chemical vapor deposition
Process for the preparation of silica nanowires using amorphous silicon.
The method according to claim 1,
In the step (b), the metal thin film layer may be formed of nickel (Ni)
Process for the preparation of silica nanowires using amorphous silicon.

The method according to claim 1,
Wherein the step (c) comprises annealing the substrate on which the amorphous silicon thin film layer and the metal thin film layer are deposited under a nitrogen gas containing oxygen
Process for the preparation of silica nanowires using amorphous silicon.
A method for producing a silica nanowire using amorphous silicon according to any one of claims 1 to 5,
Silica nanowires.
The method of claim 6, wherein the silica nanowire is amorphous silica composed of SiOx, and x is 0 < x < 3
Silica nanowires.
A photoelectric device manufactured using the silica nanowire according to claim 7.

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