KR101342490B1 - Manufacturing method of non-catalyst type nanowire, nanowire, solar cells and led using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a non-catalyst type nanowire with a large area, the nanowire with the large area, a solar cell, and an LED using the same. Contamination due to a catalyst is prevented and a nanowire with high density is grown on a semiconductor substrate with a large area by including the steps of: (a) coating the semiconductor substrate with a surfactant; (b) transferring the substrate coated with the surfactant to a reactor; and (c) growing the nanowire on the semiconductor substrate with an MOCVD method after III group organic metal and V group gas or organic metal are injected into the reactor.

Description

Manufacturing method of non-catalyst type nanowire, nanowire, solar cells and LED using the same}

The present invention relates to a method for producing a large-area nanowire, a large-area nanowire, a solar cell and a light emitting diode using the same, which are capable of growing high-density nanowires over a semiconductor substrate without using a catalyst.

Nano-sized, small diameter materials have emerged as a very important field in the scientific community because of their new physicochemical properties, namely their unique electrical, optical, and mechanical properties. Researches on nanostructures that have been conducted up to now show new possibilities such as quantum size effects and future optical device materials.

Nanowires can be applied not only to optical devices including nanoelectronic devices and semiconductor light emitting devices, but also to environmentally related materials. In particular, semiconductor nano compounds are attracting attention as new optical device materials as well as single electronic transistor (SET) devices.

In particular, the manufacturing technology of nanowires has great significance in terms of the development of important device materials that are the basis of nanotechnology.

In addition, given that the nanoworld is still unexplored, nanowires can be applied to a wider field.

To date, research on nanowire synthesis has been actively conducted, and nanowires made of various materials such as Si, Ge, GaN, and GaAs have been reported. In the manufacture of such nanowires, a vapor-phase transport process using a metal such as gold as a catalyst, a method using physical vapor deposition, etc. are used, and a nanowire having a diameter of about 30 to 150 nm is used. A method of synthesizing has been developed.

In the conventional method of synthesizing nanowires using a metal catalyst, a nanometer-sized liquid droplet is prepared by annealing a metal such as gold at an appropriate temperature and using the catalyst as a catalyst. In this method, since it is synthesized through the precipitation process after being solidified by the liquid metal catalyst of the nanowire, the trace metal catalysts cannot be prevented from entering the nanowire in this process. These impurities lower the intrinsic properties of the nanowires, and in particular, in the case of semiconductor nanowires, these impurities form an unintended defect level, which causes a problem of rapidly deteriorating the electrical and optical properties.

In order to solve such a problem, Korean Patent No. 0456016 discloses a technique for growing nanowires by organometallic chemical vapor deposition using a zinc-containing organometal, an oxygen-containing gas, or an oxygen-containing organic material. Since the technique does not use a metal catalyst, impurities do not enter the nanowires, but when used in a large-area substrate, there is a problem in that the nanowires are formed locally instead of the entire nanowires.

Therefore, there is a demand for a nanowire growth method capable of growing a high density nanowires over a large-area semiconductor substrate while preventing contamination by a catalyst.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a large-area non-catalytic nanowire in which high-density nanowires can be grown on a large-area semiconductor substrate while preventing contamination by a catalyst.

In addition, another object of the present invention is to provide a nanowire manufactured by the method for producing the nanowire.

In addition, another object of the present invention is to provide a solar cell using a nanowire manufactured by the method of manufacturing the nanowire.

In addition, another object of the present invention is to provide a light emitting diode using a nanowire manufactured by the method of manufacturing the nanowire.

Nanowire manufacturing method of the present invention for achieving the above object comprises the steps of (a) coating a semiconductor substrate with a surfactant; (b) transferring the substrate coated with the surfactant to a reactor; And (c) injecting an organometallic group or group V-containing metal or a gas into the reactor and growing nanowires on the semiconductor substrate by organometallic chemical vapor deposition (MOCVD). .

In the step (a), the semiconductor substrate may be one selected from the group consisting of silicon, sapphire, glass, aluminum oxide and magnesium oxide, and the surfactant may be one selected from the group consisting of polylysine, polyethyleneimine, chitosan, and the like. .

In the step (a), the surfactant may be coated such that the coating film has a thickness of 10 to 70 nm.

In the step (c), the group III organic metal may be a mixed metal in which at least one metal selected from the group consisting of gallium, indium, aluminum, and thallium is mixed, preferably gallium and indium.

In the step (c), the group III organometallic may be at least one selected from the group consisting of dimethyl indium, dimethyl gallium, dimethyl aluminum, diethyl indium, diethyl gallium, and diethyl aluminum indium.

In step (c), the molecular flow of the group III organic metal may be 1 × 10 ⁻³ to 1 × 10 ⁻⁷ mol / min.

Group (V) in the step (c) may be one selected from the group consisting of nitrogen, phosphorus, arsenic and antimony, preferably arsenic.

In the step (c), the gas containing group V may be one selected from the group consisting of nitrogen dioxide, acin and phosphine, and the group V-containing organometallic is specifically tributylacin, tributyl. Phosphine, trimethyl antimony and the like.

 In the step (c), the molar ratio of the organic metal of Group III and the organic metal or gas containing Group V may be 1:10 to 300.

In the step (c), the nanowire growth may have a temperature of 450 to 800 ° C., and a pressure of 50 to 1300 mbar.

In addition, the nanowires of the present invention for achieving the above another object may be manufactured according to the above production method may be up to 200 nm in diameter, the density of the number of nanowires may be 1X10 ⁷ to 8X10 ⁹ / cm 2.

In addition, the solar cell of the present invention for achieving the above another object can use the nanowires prepared according to the manufacturing method.

In addition, the light emitting diode of the present invention for achieving the above another object can use the nanowires prepared according to the manufacturing method.

In the nanowire manufacturing method of the present invention, since nanowires are grown without using a catalyst, contamination by a catalyst can be prevented, and electrical and optical characteristics are excellent.

In addition, the nanowire manufacturing method of the present invention can form a high-density nanowire evenly over a large area (for example, 2x2 inches) of the semiconductor substrate.

In addition, when using the nanowire manufacturing method of the present invention, not only the nanowire thickness and length are uniform, but also well oriented in the direction perpendicular to the substrate, it shows better electrical and optical characteristics when applied to solar cells, light emitting diode infrared detectors, and the like.

1 is a SEM photograph taken from the upper side of the nanowires prepared according to an embodiment of the present invention.
Figure 2a is a view showing the structure of a nanowire manufactured according to an embodiment of the present invention.
Figure 2b is a SEM photograph taken at 45 ° nanowires prepared in accordance with an embodiment of the present invention.
Figure 2c is a SEM photograph taken from the side of the nanowires prepared according to an embodiment of the present invention.
Figure 3 is a SEM photograph taken at 45 ° nanowires prepared according to a conventional method.
Figure 4 is a graph measured by XRD nanowires prepared according to an embodiment of the present invention.
5A is a view illustrating a core-shell structure of a nanowire manufactured according to an embodiment of the present invention.
5B is a SEM photograph of a core-shell structure formed using a nanowire manufactured according to an embodiment of the present invention.

The present invention relates to a method for producing a large-area nanowire, a large-area nanowire, a solar cell and a light emitting diode using the same, which are capable of growing high-density nanowires over a semiconductor substrate without using a catalyst.

Hereinafter, the present invention will be described in detail.

Method for producing a large area nanowire of the non-catalyst method of the present invention comprises the steps of (a) coating a semiconductor substrate with a surfactant; (b) transferring the substrate coated with the surfactant to a reactor; And (c) injecting an organometallic group or group V-containing metal or gas into the reactor and growing nanowires on the semiconductor substrate by organometallic chemical vapor deposition (MOCVD).

First, in step (a), the surface of the semiconductor substrate from which the native oxide is removed is coated with a surfactant by using a buffered oxide etchant (BOE) and HF solution.

The thickness of the coating film coated with the surfactant is 10 to 70 nm, preferably 30 to 50 nm. When the thickness of the coating film does not satisfy the above range, the nanowire may grow only on a part of the large-area semiconductor substrate, and the thickness and length of the nanowire may not be uniform.

The semiconductor substrate is not particularly limited, and may be, for example, one substrate selected from the group consisting of silicon, sapphire, glass, aluminum oxide (Al ₂ O ₃ (0001) or Al ₂ O ₃ (1100)) and magnesium oxide. And preferably a silicon substrate.

The surfactant causes a charge on the surface of the semiconductor substrate so that when the nanowires are grown in the reactor, the precursor material is well adsorbed on the surface so that the reaction occurs uniformly. As the nanowires are evenly grown on the entire substrate, specifically, one or two or more selected from the group consisting of poly (lysine), polyethyleneimine, chitosan, and the like, may be mentioned.

If nanowires are grown without a surfactant coated on the semiconductor substrate, the nanowires may be locally grown on only part of the semiconductor substrate.

Next, in step (b), the substrate coated with the surfactant in step (a) is transferred to the reactor.

If a native oxide is formed on the surface of the coated substrate, the nanowire may not grow or may grow locally on a part of the semiconductor substrate, and thus, the native oxide may be rapidly transferred to the reactor to prevent the formation of the native oxide.

Next, in the step (c), the precursor material is injected into the reactor, and the nanowires are grown by conventional organometallic chemical vapor deposition (MOCVD). In this case, the reactor is an organometallic chemical vapor deposition machine, and the nanowires are grown by the lattice constant difference between the semiconductor substrate and the precursor materials.

As the precursor material, an organometallic metal or gas containing group III and group V is used, and an inert gas such as argon is used as a carrier gas. Each precursor material is individually injected through a line into a reactor, and the precursor materials are chemically reacted in the reactor to deposit and grow nanowires on a semiconductor substrate.

At this time, the temperature of the reactor is maintained at 450 to 800 ℃, preferably 500 to 650 ℃; The pressure is maintained between 50 and 1300 mbar, preferably between 50 and 900 mbar. When the temperature and / or pressure of the reactor is outside the above range, the nanowires may not grow uniformly or the nanowires may grow only on a part of the substrate.

The group III organometallic may be one or two or more metals selected from the group consisting of gallium, indium, aluminum and thallium, preferably a mixed metal in which gallium and indium are mixed.

Specifically, the group III organic metal injected into the reactor is one or two or more selected from the group consisting of dimethyl indium, dimethyl gallium, dimethyl aluminum, diethyl indium, diethyl gallium, and diethyl aluminum indium. Preferably, the gallium compound and the indium compound are mixed in the group consisting of dimethyl indium, dimethyl gallium and diethyl aluminum indium.

The molecular flow of the group III organometal is 1X10 ^-3 to 1X10 ^-7 mol / min. When the molecular flow is out of the above range, the thickness and length of the nanowire may not grow uniformly, and the nanowire may not grow on the entire surface of the substrate.

Group V may be one selected from the group consisting of nitrogen, phosphorus, arsenic, and antimony, and may be preferably arsenic.

Specifically, the group V-containing gas may be one selected from the group consisting of nitrogen dioxide, arsine, and phosphine, and preferably, acin. In addition, the organometallic group V-containing may be one selected from the group consisting of tributylacin, tributylphosphine, and trimethyl antimony, and preferably tributylacin.

At this time, the molar ratio of the organometallic of Group III and the organometallic or gas containing Group V is from 1:10 to 300, preferably from 1:10 to 200. When the molar ratio of the group V-organic metal or gas based on the group III organic metal is out of the above range, the grown nanowires may not be uniform or may not grow on the entire surface of the substrate.

By using a gas containing an organometallic and arsenic mixed with a gallium compound and an indium compound, In _x Ga _{1- x} As (X is a minority of 0.1 to 0.9) can be manufactured.

The density of the number of nanowires prepared according to the present invention is 1X10 ⁷ to 8X10 ⁹ / cm 2 (FIG. 1), since the nanowires prepared are grown as nucleating agents on the surface of the surfactant without using a metal catalyst. Contamination by the catalyst is prevented, so excellent electrical and optical characteristics.

In addition, the diameter of the nanowires can be adjusted to 200 nm or less, preferably 20 to 200 nm, and since the thickness and length of the nanowires produced are uniform as the reaction time elapses, the nanowires can be easily applied to a solar cell, a light emitting diode infrared detector, and the like. .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example  One.

Polylysine is coated on a silicon substrate to a thickness of about 50 nm and then quickly transferred to an organometallic chemical vapor deposition machine. Indium gallium arsenide nanowires on silicon substrates were injected over 1 hour by a mixture of dimethylindium and dimethylgallium and acin, respectively, injected through the line into the organometallic chemical vapor deposition system and undergoing a chemical reaction at 600 ° C. and 300 mbar pressure. Was deposited and grown. At this time, the molecular flow of the dimethyl indium and dimethylgallium mixture is 5X10 ^-5 mol / min, and the molar ratio of the dimethyl indium and dimethylgallium mixture and acin is 1:90.

Comparative Example  One.

In the same manner as in Example 1, the nanowires were grown without coating with polylysine.

Test Example  One. Nanaru SEM Measured by

2 is a SEM photograph of the nanowires prepared in Examples and Comparative Examples according to the present invention.

As shown in Figure 2a, the nanowires prepared according to the embodiment of the present invention is n-type nanowires formed perpendicular to the semiconductor substrate.

Also, as shown in FIGS. 2B and 2B, the SEM photographs taken at 45 ° and the SEM photographs taken from the side of the substrate on which the nanowires are grown according to the exemplary embodiment of the present invention are grown evenly without impurities. Compared to the nanowires (FIG. 3) prepared in Comparative Example 1, nanowires are grown with almost no empty space in the semiconductor substrate.

On the other hand, looking at the SEM photograph (FIG. 3) of the n-type nanowires prepared in Comparative Example 1, it can be seen that the thickness of the generated nanowires is not uniform and the nanowires do not grow much.

Test Example  2. Nanaru XRD Measure

4 is a graph measured by XRD of the nanowires prepared in Examples according to the present invention.

As shown in FIG. 4, the nanowires prepared in Examples according to the present invention were grown heteroepitaxially (heteroepitaxially) on a silicon substrate.

As described above, the nanowire manufactured according to the present invention may be formed in a core-shell structure as shown in FIG. 5A and applied to a solar cell, a light emitting diode, and the like.

Figure 5b is a SEM photograph taken at 45 ° after the nanowires were formed in a core-shell structure. As shown in FIG. 5B, it can be seen that the thickness and length are uniform even after the core-shell structure is formed. Therefore, it has excellent electrical and optical characteristics when applied to solar cells, light emitting diodes and the like.

Claims (19)

(a) coating the semiconductor substrate with a surfactant;
(b) transferring the substrate coated with the surfactant to a reactor; And
(c) injecting an organometallic group or group V-containing metal or gas into the reactor, and then growing nanowires on the semiconductor substrate by organometallic chemical vapor deposition (MOCVD);
In step (c), the group V-containing organic metal is one selected from the group consisting of tributylacin, tributylphosphine, and trimethyl antimony, and the group V-containing gas is nitrogen dioxide, acine and phosphine. Method for producing a large area non-catalyst nanowire, characterized in that one selected from the group consisting of. The method of claim 1, wherein the semiconductor substrate in step (a) is at least one selected from the group consisting of silicon, sapphire, glass, aluminum oxide, and magnesium oxide. The method according to claim 1, wherein the surfactant in the step (a) is a method for producing a large area non-catalytic nanowire, characterized in that the one selected from the group consisting of polylysine, polyethyleneimine and chitosan. The method of claim 1, wherein the surfactant is coated in the step (a) such that the coating film has a thickness of 10 to 70 nm. The method of claim 1, wherein the group III organic metal in step (c) is at least one metal selected from the group consisting of gallium, indium, aluminum, and thallium. The method according to claim 1, wherein the group III organic metal in step (c) is a mixed metal in which gallium and indium are mixed. The method of claim 1, wherein in step (c) the Group III organometal is at least one selected from the group consisting of dimethyl indium, dimethylgallium, dimethylaluminum, diethylindium, diethylgallium and indiethylaluminum indium. A method for producing a large area nanowire without a catalyst, characterized in that. The method of claim 1, wherein the molecular flow of the group III organometallic metal in step (c) is 1X10 ^-3 to 1X10 ^-7 mol / min. The method according to claim 1, wherein in the step (c), Group V is one selected from the group consisting of nitrogen, phosphorus, arsenic, and antimony. The method of claim 1, wherein in the step (c), Group V is arsenic. delete delete The method of claim 1, wherein the molar ratio of the group III organic metal and the group V-containing organic metal or gas in the step (c) is 1: 10 ~ 300, the production of a non-catalytic large-area nanowire Way. The method of claim 1, wherein the nanowires grow at a temperature of 450 to 800 ° C. in the step (c). The method according to claim 1, wherein the pressure during nanowire growth in step (c) is 50 to 1300 mbar. A nanowire having a diameter of 200 nm or less manufactured according to the method of any one of claims 1 to 10 and 13 to 15. The nanowire of claim 16, wherein the nanowire has a density of 1 × ^{10 7} to 8X10 ⁹ / cm 2. A solar cell manufactured using a nanowire manufactured according to any one of claims 1 to 10 and 13 to 15. A light emitting diode manufactured using a nanowire manufactured according to any one of claims 1 to 10 and 13 to 15.

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