KR20210146090A - Cadmium Arsenide Nanowire and Preparation Method Thereof - Google Patents

Abstract

The present invention relates to a cadmium arsenide nanowire, which is a Dirac metalloid compound, and a method for manufacturing the same. The cadmium arsenide nanowire of the present invention is a Dirac metalloid compound, can be used in an electrical and electronic device including a magnetic sensor, a light sensor, a superconductor, spintronics, or a quantum computer device, and has very low electrical resistance to be applied to various types of high-performance electronic materials. In addition, the method for manufacturing a cadmium arsenide nanowire of the present invention can be performed in a low-cost process at a relatively low temperature.

Description

Cadmium Arsenide Nanowire and Preparation Method Thereof

The present invention relates to a cadmium arsenide nanowire and a method for manufacturing the same, and more particularly, to a cadmium arsenide nanowire which is a Dirac metalloid compound for a magnetic sensor, superconductor, spintronics, or quantum computer electrical device, and a method for manufacturing the same will be.

Recently, research on the development of electrical materials for magnetic sensors, superconductors, spintronics, or quantum computer devices is active, and the key to developing high-performance electrical materials is to reduce energy loss due to resistance.

Three-dimensional (3D) metalloids, which can have a linear energy band dispersion relationship such as two-dimensional (2D) structure graphene and 2D graphene, cause electric resistance to flow only at the edge or surface but not inside. Since it is minimized, interest in 2D graphene and 3D metalloids is greatly increasing. 2D graphene and 3D metalloids are also called topological insulators or topological materials with minimal resistance.

The biggest characteristic of 3D metalloids is that electrons of 3D metalloids move as if they have no mass, whereas electrons of ordinary materials have mass. Therefore, the electrons of the 3D metalloid are extremely sensitive to the strength and direction of the magnetic field.

Cadmium arsenide (Cd ₃ As ₂ ), sodium bismutide (Sodium Bismuthide, Na ₃ Bi), etc. are classified as 3D Dirac semimetal (DSM).

In 3D Dirac metalloids (DSM), two states in which the energy bands always have opposite spin directions form a double degeneracy with the same energy, and the conduction band and the valence band are at the Fermi level ( Fermi level) around the cone-shaped Dirac cone is formed.

In addition, the Diraccon forms a Dirac point, an energy intersection protected by symmetry at a point where energy is equal in all momentum directions.

The Dirac point has a characteristic in that time-reversal symmetry or spatial inversion symmetry is broken, and two or four Dirac cones constituting the Dirac point are separated in momentum space. As a result, the Dirac semimetal (DSM) exhibits a Weyl semimetal characteristic through a topological phase transition.

In addition, the 3D Dirac metalloid has the above characteristics in the facet rather than the edge, unlike the 2D phase material.

And, 3D Dirac metalloid has excellent carrier mobility (~ ¹⁰⁷ cm ² /Vs at 5K for single crystal) due to its unique energy band structure and has large magnetoresistance (magnetoresistance, MR, change up to 2000%).

And, 3D Dirac metalloid exhibits very interesting magnetic quantum phenomena such as Landau quantization and Shubnikov-de Haas effect, and is a next-generation quantum material attracting attention from many researchers. These three-dimensional Dirac metalloids are expected to be able to precisely make magnetic sensors that can be used in various fields such as smartphones and magnetic resonance imaging (MRI) devices. In addition, it is emerging as a core material for quantum computers and is a material that can accelerate the development of new electronic devices such as spintronics.

In recent years, interest in the development of a one-dimensional nanostructured Dirac metalloid or a two-dimensional nanostructured Dirac metalloid having a limited dimension of a nanoscale, further from the three-dimensional Dirac metalloid in the bulk state, is growing.

_{Cadmium arsenide (Cd 3} As ₂ ), which is a kind of Dirac metalloid, is a body-centered tetragonal (bct) crystal phase, a first primitive tetragonal (pt1) crystal phase, and a second primitive tetragonal phase. (second primitive tetragonal, pt2) It exists as a crystalline phase.

The cadmium arsenide (Cd ₃ As ₂₎ the body centered tetragonal (bct) crystal phase is present at room temperature to 220 ℃, the cadmium arsenide (Cd ₃ As ₂₎ the first primitive tetragonal (first primitive tetragonal of , pt1) The crystalline phase exists at 230 °C to 456 °C, and the _{second primitive tetragonal (pt2) crystalline phase of the cadmium arsenide (Cd 3} As ₂ ) exists at 475 °C to 595 °C.

_{Among them, cadmium arsenide (Cd 3} As ₂ ) in the body-centered tetragonal (bct) crystalline phase has been mainly studied.

The cadmium arsenide (Cd ₃ As ₂₎ the first primitive tetragonal (pt1) crystal phase, and the cadmium arsenide (Cd ₃ As ₂₎ the second raw tetragonal (pt2) crystal phase is the cadmium in the theoretical calculation study It was predicted that arsenide (Cd ₃ As ₂ ) could become a 3D Dirac metalloid by modification of the Dirac point in the same way as the body-centered tetragonal (bct) crystal phase.

However, experimentally, the weight-centered tetragonal (bct) crystal phase, the first primitive tetragonal (pt1) crystal phase, or the second primitive tetragonal (pt2) crystal phase of the cadmium arsenide (Cd ₃ As _{2 ) Dirac metalloid} No studies have yet been reported on synthesizing by pure separation into individual crystal phases without mixing them with each other.

Furthermore, the cadmium arsenide (Cd ₃ As _2), while synthesizing the Dirac metalloid to 1D nanowires than the bulk, the cadmium arsenide (Cd ₃ As ₂₎ Dirac gave the body centered tetragonal (bct) of metal, the A technique for selectively separating and synthesizing the first primitive tetragonal (pt1) or the second primitive tetragonal (pt2) crystal phases into individual crystal phases has not been reported worldwide.

_{In addition, cadmium arsenide (Cd 3} As ₂ ) nanowires having a one-dimensional shape such as a carrier movement path and having a reduced cross-sectional area to a nano size are suitable materials for nanoscale electronic components.

Therefore, in order to maximize the carrier mobility, magnetic resistance, and quantum effect of cadmium arsenide nanowires, there are three types of crystalline phases (body-centered tetragonal (bct) crystalline phase and two types of primitive tetragonal ( It is urgent to secure a technology to purely separate and synthesize pt1, pt2) crystal phases into individual crystal phases, and to control the crystal growth direction of each crystal phase.

Chinese Laid-Open Patent Publication No. 108109904 China Registered Patent Publication No. 105006485 China Registered Patent Publication No. 105490146 Chinese Laid-Open Patent Publication No. 109586154

An object of the present invention is to provide a cadmium arsenide nanowire synthesized by separation into a single crystal phase.

Another object of the present invention is to provide a cadmium arsenide nanowire capable of controlling the crystal growth direction of the cadmium arsenide nanowire.

In addition, an object of the present invention is to provide a simple and economical manufacturing method capable of producing such a cadmium arsenide nanowire inexpensively.

The nanowire according to an embodiment of the present invention includes a cadmium arsenide nanowire, which is a Dirac semimetal compound.

The nanowire according to an embodiment of the present invention may be a single crystal.

The crystalline phase of the nanowire according to an embodiment of the present invention may be a weight-centered tetragonal (bct) crystalline phase, a first tetragonal (pt1) crystalline phase, or a second primordial tetragonal (pt2) crystalline phase.

In XRD analysis of the body-centered tetragonal (bct) crystalline nanowire according to an embodiment of the present invention, the diffraction angle 2θ of the (224) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (408) peak is 40.0° to It may appear at 40.3°, and the diffraction angle 2θ of the (440) peak may appear at 40.1° to 40.4°.

In addition, a space group of the body-centered tetragonal (bct) crystalline nanowire according to an embodiment of the present invention may be I4 ₁ /acd or I4 ₁ cd.

In this case, the lattice constant a of the weight-centered tetragonal (bct) crystalline nanowire according to the embodiment of the present invention may be 12.665 Å, and the lattice constant c may be 25.443 Å.

일 수 있다.And, the crystal growth direction of the weight-centered tetragonal (bct) crystalline phase nanowire according to an embodiment of the present invention is

can be

In addition, in XRD analysis of the first primitive tetragonal (pt1) crystalline nanowire according to an embodiment of the present invention, the diffraction angle 2θ of the (224) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (408) peak is It may appear at 40.0° to 40.3°, and the diffraction angle 2θ of the (440) peak may appear at 40.1° to 40.4°.

In addition, a space group of the first primitive tetragonal (pt1) crystalline nanowire according to an embodiment of the present invention _{may be P4 2} /nbc.

In this case, the lattice constant a of the first primitive tetragonal (pt1) crystalline nanowire according to the embodiment of the present invention may be 12.662 Å, and the lattice constant c may be 25.452 Å.

일 수 있다.And, the crystal growth direction of the first primitive tetragonal (pt1) crystal phase nanowire according to the embodiment of the present invention is

can be

In addition, in XRD analysis of the second primitive tetragonal (pt2) crystalline nanowire according to an embodiment of the present invention, the diffraction angle 2θ of the (202) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (400) peak is It may appear at 39.9° to 40.2°, and the diffraction angle 2θ of the (224) peak may appear at 40.1° to 40.4°.

In addition, a space group of the second primitive tetragonal (pt2) crystalline nanowire according to an embodiment of the present invention _{may be P4 2} /nmc.

In this case, the lattice constant a of the second primitive tetragonal (pt2) crystalline nanowire according to the embodiment of the present invention may be 8.994 Å, and the lattice constant c may be 12.622 Å.

In addition, the crystal growth direction of the second primitive tetragonal (pt2) crystalline nanowire according to an embodiment of the present invention may be _{[100] pt2.}

In addition, the diameter of the nanowire according to an embodiment of the present invention may be 60 nm to 200 nm, and the length of the nanowire may be 55 μm to 300 μm.

Here, the cadmium element and the arsenic element constituting the nanowire according to the embodiment of the present invention may be uniformly distributed in the nanowire.

Cadmium arsenide nanowire manufacturing method according to an embodiment of the present invention

Preparing an electric furnace consisting of cadmium arsenide powder, a silicon substrate on which a gold thin film is deposited, and a two-stage (one-phase and two-phase) reactor capable of temperature control;

putting the cadmium arsenide powder into the ceramic boat and then placing it in the single-phase reactor, and placing the gold thin film-deposited silicon substrate in the two-phase reactor at a distance of 15 cm to 25 cm from the ceramic boat;

An inert gas of argon gas or nitrogen gas is supplied into the electric furnace at 300 to 800 sccm (standard cubic centimeter per minute) during the reaction time, and the temperature of the cadmium arsenide powder placed in the one-phase reactor is 350 ° C. to 800 ° C., synthesizing for 5 minutes to 3 hours while maintaining the temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor at 250° C. to 600° C.; and

and slowly cooling the compound to room temperature to obtain a single crystalline cadmium arsenide nanowire.

Here, in the method for manufacturing cadmium arsenide nanowires according to an embodiment of the present invention, the molar ratio (Au:Cd) of gold in the silicon substrate on which the gold thin film is deposited and cadmium in the cadmium arsenide powder is 1:1 to 1:3 can be

In addition, there is provided an electrical and electronic device manufactured including a cadmium arsenide nanowire according to an embodiment of the present invention.

Here, the electrical and electronic device may include a magnetic sensor, an optical sensor, a superconductor, a spintronic device, or a quantum computer device.

The present invention can be synthesized by selectively separating cadmium arsenide nanowires into nanowires of each single crystal phase.

In addition, the present invention can control the crystal growth direction of the cadmium arsenide nanowire.

In addition, in the present invention, the existence of cadmium arsenide nanowires in the first tetragonal (pt1) crystalline phase and the cadmium arsenide nanowires in the second tetragonal (pt2) crystalline phase can be identified through experimental data.

In addition, the cadmium arsenide nanowire of the present invention is a Dirac metalloid compound with minimal resistance, and thus can be used in various types of high-performance electronic materials including superconductors.

In addition, the cadmium arsenide nanowire of the present invention is a Dirac metalloid compound and can be used in magnetic sensors, optical sensors, and spintronic devices.

In addition, the cadmium arsenide nanowire of the present invention can be used as a core element of a quantum computer as a Dirac metalloid compound.

In addition, the method for manufacturing cadmium arsenide nanowires of the present invention can be performed at a relatively low temperature and in a low-cost process.

1 is a schematic diagram of a chemical vapor transport method (Chemical Vapor Transport, CVT) synthesis equipment of cadmium arsenide nanowires according to Examples and Comparative Examples of the present invention.
2 is an X-ray diffraction (XRD, X-Ray Diffraction) pattern of cadmium arsenide nanowires in a weight-centered tetragonal (bct) crystal phase according to an embodiment of the present invention.
3 is an X-ray diffraction (XRD, X-Ray Diffraction) pattern of a cadmium arsenide nanowire in a first primitive tetragonal (pt1) crystal phase according to an embodiment of the present invention.
4 is an X-ray diffraction (XRD, X-Ray Diffraction) pattern of a cadmium arsenide nanowire in a second primitive tetragonal (pt2) crystal phase according to an embodiment of the present invention.
5A is a scanning electron microscope (SEM) image of a cadmium arsenide nanowire in a first primitive tetragonal (pt1) crystal phase according to an embodiment of the present invention.
5B is a transmission electron microscope (TEM) image of a cadmium arsenide nanowire in a first primitive tetragonal (pt1) crystal phase according to an embodiment of the present invention.
5c is an energy-dispersive X-ray spectroscopy (EDX) element mapping result and line profile of a cadmium arsenide nanowire in a first primitive tetragonal (pt1) crystal phase according to an embodiment of the present invention; FIG. profile) analysis result.
6 is a diagram of a unit cell and crystallographic axis of a weight-centered tetragonal (bct) crystalline phase, a first tetragonal (pt1) crystalline phase, or a second primordial tetragonal (pt2) crystalline phase cadmium arsenide nanowire according to an embodiment of the present invention; It is a diagram showing the correlation.
7 is an FFT (Fast Fourier Transform) image and SAED (Selected Area) image and SAED (Selected Area) analysis of the crystal growth direction and the crystal phase of the cadmium arsenide nanowire of the body-centered tetragonal (bct) crystalline phase according to an embodiment of the present invention. Electron Diffraction) pattern.
8 is an FFT (Fast Fourier Transform) image and SAED (Selected) image of the crystal growth direction and crystal phase of the first primitive tetragonal (pt1) crystalline phase cadmium arsenide nanowire according to an embodiment of the present invention analyzed with a transmission electron microscope (TEM). Area Electron Diffraction) pattern.
9 is an FFT (Fast Fourier Transform) image and SAED (Selected) analysis of the crystal growth direction and crystalline phase of the second primitive tetragonal (pt2) crystalline cadmium arsenide nanowire according to an embodiment of the present invention with a transmission electron microscope (TEM). Area Electron Diffraction) pattern.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention, and therefore, the scope of the present invention is not to be construed as being limited by these examples.

As used herein, an expression such as “comprising” is understood as an open-ended term that includes the possibility of including other embodiments, unless specifically stated otherwise in the phrase or sentence in which the expression is included. should be

As used herein, “preferred” and “preferably” refer to embodiments of the invention that may provide certain advantages under certain circumstances. However, other embodiments may also be desirable, under the same or other circumstances. Additionally, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

Hereinafter, the cadmium arsenide nanowire of the present invention will be described in detail.

The present invention provides a cadmium arsenide nanowire, which is a Dirac semimetal compound.

The cadmium arsenide nanowire may be a single crystal.

Here, when the cadmium arsenide nanowire is a single crystal, an electron beam is diffracted by a single crystal in a Fast Fourier Transform (FFT) image of a transmission electron microscope (TEM) and a Selected Area Electron Diffraction (SAED) pattern to form a dot shape. It can be seen from what appears to be separated.

In addition, the crystalline phase of the cadmium arsenide nanowire may be a weight-centered tetragonal (bct) crystal phase, a first primitive tetragonal (pt1) crystal phase, or a second primitive tetragonal (pt2) crystal phase.

In the present invention, the weight-centered tetragonal (bct) crystalline phase, the first tetragonal (pt1) crystalline phase, or the second primordial tetragonal (pt2) crystalline phase, which are the crystalline phases of the cadmium arsenide nanowire, are not mixed with each other and are separated into individual crystalline phases. and can be synthesized.

In addition, the present invention selectively selects three types of crystal phases of the body-centered tetragonal (bct) crystal phase, the first primitive tetragonal (pt1) crystal phase, or the second primitive tetragonal (pt2) crystal phase, which is the crystal phase of the cadmium arsenide nanowire. can be synthesized.

Here, the cadmium arsenide nanowire in the body-centered tetragonal (bct) crystal phase is denoted as _{bct-Cd 3} As _{2 .}

In addition, the cadmium arsenide nanowire in the first primitive tetragonal (pt1) crystal phase is denoted as _{pt1-Cd 3} As _{2 .}

In addition, the cadmium arsenide nanowire in the second primitive tetragonal (pt2) crystal phase is denoted as _{pt2-Cd 3} As _{2 .}

Here, in XRD analysis of the body-centered tetragonal (bct) crystalline nanowire, the diffraction angle 2θ of the (224) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (408) peak is 40.0° to 40.3°, The diffraction angle 2θ of the (440) peak may appear at 40.1° to 40.4°.

In addition, a space group of the body-centered tetragonal (bct) crystalline nanowire may be I4 ₁ /acd or I4 ₁ cd.

In addition, the lattice constant a of the weight-centered tetragonal (bct) crystalline nanowire may be 12.665 Å, and the lattice constant c may be 25.443 Å.

일 수 있다.The crystal growth direction of the weight-centered tetragonal (bct) crystal phase nanowire is

can be

And, in XRD analysis of the first primitive tetragonal (pt1) crystalline nanowire, the diffraction angle 2θ of the (224) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (408) peak is 40.0° to 40.3° , (440) The diffraction angle 2θ of the peak may appear at 40.1° to 40.4°.

A space group of the first primitive tetragonal (pt1) crystalline nanowire _{may be P4 2} /nbc.

In addition, the lattice constant a of the first primitive tetragonal (pt1) crystalline nanowire may be 12.662 Å, and the lattice constant c may be 25.452 Å.

일 수 있다.The crystal growth direction of the first primitive tetragonal (pt1) crystalline nanowire is

can be

And, in the XRD analysis of the second primitive tetragonal (pt2) crystalline nanowire, the diffraction angle 2θ of the (202) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (400) peak is 39.9° to 40.2°. , (224), the diffraction angle 2θ of the peak may appear at 40.1° to 40.4°.

A space group of the second primitive tetragonal (pt2) crystalline nanowire _{may be P4 2} /nmc.

In addition, the lattice constant a of the second primitive tetragonal (pt2) crystalline nanowire may be 8.994 Å, and the lattice constant c may be 12.622 Å.

The crystal growth direction of the second primitive tetragonal (pt2) crystalline nanowire may be _{[100] pt2.}

In addition, the diameter of the nanowire may be 60 nm to 200 nm, and the length of the nanowire may be 55 μm to 300 μm.

In addition, cadmium element and arsenic element constituting the nanowire may be evenly distributed in the nanowire.

Hereinafter, the cadmium arsenide nanowire manufacturing method of the present invention will be described in detail.

The method for manufacturing cadmium arsenide nanowires of the present invention is

Preparing an electric furnace consisting of cadmium arsenide powder, a silicon substrate on which a gold thin film is deposited, and a two-stage (one-phase and two-phase) reactor capable of temperature control;

putting the cadmium arsenide powder into the ceramic boat and then placing it in the single-phase reactor, and placing the gold thin film-deposited silicon substrate in the two-phase reactor at a distance of 15 cm to 25 cm from the ceramic boat;

An inert gas of argon gas or nitrogen gas is supplied into the electric furnace at 300 to 800 sccm (standard cubic centimeter per minute) during the reaction time, and the temperature of the cadmium arsenide powder placed in the one-phase reactor is 350 ° C. to 800 ° C., synthesizing for 5 minutes to 3 hours while maintaining the temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor at 250° C. to 600° C.; and

and slowly cooling the compound to room temperature to obtain a single crystalline cadmium arsenide nanowire.

Here, the synthesis equipment is an electric furnace that can accommodate a cylindrical tube and a thin film substrate, and is composed of a one-phase reactor and a two-phase reactor, which are two-stage reactors capable of temperature control.

First, put cadmium arsenide powder in a ceramic boat, put it in the cylindrical tube of the one-phase reactor, and place a gold thin film deposition silicon substrate in the place where the thin film substrate of the two-phase reactor is 15 cm to 25 cm away from the ceramic boat .

The gold deposition thickness of the gold thin film deposition silicon substrate is 3 nm to 20 nm.

During the synthesis reaction time, an inert gas of argon gas or nitrogen gas is supplied into the electric furnace at 300 to 800 sccm (standard cubic centimeter per minute).

Then, the temperature of the cadmium arsenide powder placed in the one-phase reactor is 350 ℃ to 800 ℃. The temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor is maintained at 250° C. to 600° C. and synthesized for 5 minutes to 3 hours.

Thereafter, the compound is slowly cooled to room temperature to obtain a single crystalline cadmium arsenide nanowire.

Here, the cadmium arsenide nanowire may have different reaction temperature and reaction time according to each crystal phase.

First, the first-phase reaction temperature of the cadmium arsenide nanowire of the body-centered tetragonal (bct) crystal phase is 350 °C to 550 °C, the two-phase reaction temperature is 250 °C to 450 °C, and the reaction time is 30 minutes to 3 hours. .

And, the first-phase reaction temperature of the cadmium arsenide nanowire of the first primitive tetragonal (pt1) crystal phase is 400 ℃ to 600 ℃, the second-phase reaction temperature is 300 ℃ to 500 ℃, the reaction time is 20 minutes to 2 hours am.

In addition, the first-phase reaction temperature of the cadmium arsenide nanowire of the second primitive tetragonal (pt2) crystal phase is 450 to 800 °C, the two-phase reaction temperature is 350 °C to 600 °C, and the reaction time is 5 minutes to 1 hour am.

Therefore, the cadmium arsenide nanowires of the three types of crystal phases can be synthesized by selectively separating each crystal phase at different reaction temperatures and reaction times.

In this case, the molar ratio (Au:Cd) of gold of the silicon substrate on which the gold thin film is deposited and cadmium of the cadmium arsenide powder may be 1:1 to 1:3.

In particular, when the molar ratio (Au:Cd) of the gold and the cadmium is 1:3, eutectic melting occurs around 310°C.

Here, the synthesis mechanism of the cadmium arsenide nanowire is a vapor-liquid-solid (VLS) mechanism in which gold acts as a catalyst. That is, when the reaction temperature of the first phase is raised, the cadmium arsenide powder is vaporized and moved in the direction in which the inert gas of argon gas or nitrogen gas is pushed. In addition, the gold film deposited on the silicon substrate is dissolved when the temperature rises to form gold catalyst nanoparticles in a liquid state. At this time, the vaporized cadmium (Cd) is adsorbed on the surface of the liquid gold (Au) droplet to form an alloy and melt.

Then, when Au:Cd (molar ratio) = 1:3 in the vicinity of 310 ° C., eutectic melting occurs.

And, if the vaporized cadmium arsenide powder is continuously supplied, the melting amount increases and reaches a limit value, and when the limit value is reached, saturated cadmium is precipitated.

The precipitated cadmium reacts with an arsenic (As) gas produced by vaporization on the surface of the gold catalyst to form a solid cadmium arsenide nanowire.

Here, the diameter of the cadmium arsenide nanowire is determined by the diameter size of the gold nanoparticles.

And, if the vaporized cadmium arsenide powder is continuously supplied, the growth of cadmium arsenide nanowires continues, but when the cadmium arsenide nanowires cover all the silicon substrate on which the gold thin film is deposited, the vaporized cadmium arsenide powder is applied to the gold catalyst. As it cannot reach, the growth of cadmium arsenide nanowires stops.

In addition, the present invention provides an electrical and electronic device manufactured including cadmium arsenide nanowires.

Here, the electrical and electronic device may include a magnetic sensor, an optical sensor, a superconductor, a spintronic device, or a quantum computer device.

Hereinafter, the present invention will be described in more detail through examples. It should not be construed that the scope of the present invention is limited by these examples.

<Example>

1 is a schematic diagram of a chemical vapor transport (CVT) synthesis equipment of cadmium arsenide nanowires of Examples 1 to 3 of the present invention and Comparative Examples 1 to 2 of the present invention.

The chemical vapor transport method synthesis equipment of FIG. 1 is composed of a one-phase reactor and a two-phase reactor, which are two-stage reactors capable of temperature control, and an electric furnace in which a cylindrical tube and a thin film substrate can be inserted. Cadmium arsenide powder is mounted in the one-phase reactor, and a gold-deposited silicon substrate is mounted in the two-phase reactor to synthesize a predetermined one-phase reactor reaction temperature, two-phase reactor reaction temperature and reaction time, and then slowly cool to room temperature. Cadmium arsenide nanowires were prepared as in Examples and Comparative Examples.

<Example 1> bct-Cd ₃ As ₂ Nanowire manufacturing

100 mg of cadmium arsenide (Cd ₃ As ₂ , 99%, Alfa Aesar) powder, which is a precursor, was placed in a ceramic boat, and then placed in the cylindrical tube of the 1-phase reactor of FIG. 1, and 18 cm away from the ceramic boat. A silicon substrate on which a gold thin film with a thickness of 5 nm was deposited was placed in the place where the thin film substrate of the reactor would be inserted.

During the synthesis reaction time, an inert gas of argon gas or nitrogen gas was supplied into the reactor at 500 sccm (standard cubic centimeter per minute).

Then, the reaction temperature of the cadmium arsenide powder placed in the one-phase reactor was 450 °C, and the reaction temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor was maintained at 320 °C, and the reaction time was 1 hour.

Thereafter, the composite was slowly cooled to room temperature to prepare a single crystal phase, a cadmium arsenide nanowire (bct-Cd ₃ As ₂ nanowire) in a body-centered tetragonal (bct) crystal phase.

<Example 2> pt1-Cd ₃ As ₂ Nanowire manufacturing

The reaction temperature of the cadmium arsenide powder placed in the one-phase reactor of FIG. 1 is 500 °C, and the reaction temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor is maintained at 350 °C, except for synthesizing for a reaction time of 40 minutes , was synthesized in the same manner as in Example 1 and slowly cooled to room temperature _{to prepare cadmium arsenide nanowires (pt1-Cd 3} As ₂ nanowires) in the first primitive tetragonal (pt1) crystal phase, which is a single crystal phase.

<Example 3> pt2-Cd ₃ As ₂ Nanowire manufacturing

The reaction temperature of the cadmium arsenide powder placed in the one-phase reactor of FIG. 1 is 650 ° C., and the reaction temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor is maintained at 450 ° C. Except for synthesizing for a reaction time of 10 minutes , was synthesized in the same manner as in Example 1 and slowly cooled to room temperature _{to prepare cadmium arsenide nanowires (pt2-Cd 3} As ₂ nanowires) in the second primitive tetragonal (pt2) crystal phase, which is a single crystal phase.

<Comparative Example 1> pt1-Cd ₃ As ₂ crystalline phase and pt2-Cd ₃ As ₂ Manufacture of nanowires with mixed crystalline phases

The reaction temperature of the cadmium arsenide powder placed in the one-phase reactor of FIG. 1 is 550 ° C., and the reaction temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor is 380 ° C. while synthesizing for a reaction time of 30 minutes. , was synthesized in the same manner as in Example 1 and cooled slowly to room temperature to prepare cadmium arsenide nanowires in which a first tetragonal (pt1) crystal phase and a second primitive tetragonal (pt2) crystal phase were mixed.

<Comparative Example 2> pt1-Cd ₃ As ₂ crystalline phase and pt2-Cd ₃ As ₂ Manufacture of nanowires with mixed crystalline phases

The reaction temperature of the cadmium arsenide powder placed in the one-phase reactor of FIG. 1 is 570 °C, and the reaction temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor is 420 °C while synthesizing for a reaction time of 20 minutes , was synthesized in the same manner as in Example 1 and cooled slowly to room temperature to prepare cadmium arsenide nanowires in which a first tetragonal (pt1) crystal phase and a second primitive tetragonal (pt2) crystal phase were mixed.

Cadmium Arsenide Nanowire Properties and Synthesis Conditions number crystalline phase Phase 1 temperature (℃) 2-phase temperature (℃) Reaction time (min) Example 1 bct-Cd ₃ As ₂ 450 320 60 Example 2 pt1-Cd ₃ As ₂ 500 350 40 Example 3 pt2-Cd ₃ As ₂ 650 450 10 Comparative Example 1 pt1-Cd ₃ As ₂ ,
pt2-Cd ₃ As ₂ mixed 550 380 30 Comparative Example 2 pt1-Cd ₃ As ₂ ,
pt2-Cd ₃ As ₂ mixed 570 420 20

<Experimental example>

<Experimental example> bct-Cd ₃ As ₂ Nanowire XRD measurement

FIG. 2 is an X-ray diffraction (XRD, X-Ray Diffraction) pattern of cadmium arsenide nanowires in a weight-centered tetragonal (bct) crystalline phase prepared in Example 1. FIG.

The calculated XRD pattern of the bct crystal phase was generated using the VESTA program (http://jp-minerals.org /vesta/en/), and the lattice constant was adjusted with experimental data. The lattice constant a of the bct-Cd ₃ As ₂ nanowire prepared in Example 1 was 12.665 Å, and c was 25.443 Å. When the enlarged right (408) and (440) peaks were fitted using the Voigt function, it was confirmed that they were consistent with the calculated bct values.

From the X-ray diffraction data of FIG. 2 , it was confirmed that the crystalline phase of the cadmium arsenide nanowire prepared in Example 1 was a weight-centered tetragonal (bct) crystalline phase.

Specifically, the diffraction angle 2θ of the (224) peak was measured to be 24.28°, the diffraction angle 2θ of the (408) peak was measured to be 40.15°, and the diffraction angle 2θ of the (440) peak was measured to be 40.24°.

<Experimental example> pt1-Cd ₃ As ₂ Nanowire XRD measurement

3 is an X-ray diffraction (XRD, X-Ray Diffraction) pattern of the cadmium arsenide nanowire in the first primordial tetragonal (pt1) crystal phase prepared in Example 2. Referring to FIG.

The same VESTA program (http://jp-minerals.org /vesta/en/) was used to generate a calculated XRD pattern of the pt1 crystal phase, and the lattice constant was adjusted with experimental data. It was found that the _{lattice constant a of the pt1-Cd 3} As ₂ nanowire prepared in Example 2 was 12.662 Å, and the lattice constant c was 25.452 Å. When the enlarged right (408) and (440) peaks were fitted using the Voigt function, it was confirmed that the pt1 calculated values were consistent with each other.

From the X-ray diffraction data of FIG. 3 , it was confirmed that the crystalline phase of the cadmium arsenide nanowire prepared in Example 2 was a first primitive tetragonal (pt1) crystalline phase.

Specifically, the diffraction angle 2θ of the (224) peak was measured to be 24.28°, the diffraction angle 2θ of the (408) peak was measured to be 40.15°, and the diffraction angle 2θ of the (440) peak was measured to be 40.25°.

<Experimental example> pt2-Cd ₃ As ₂ Nanowire XRD measurement

4 is an X-ray diffraction (XRD, X-Ray Diffraction) pattern of the cadmium arsenide nanowire in the second primitive tetragonal (pt2) crystal phase prepared in Example 3. FIG.

이고, 격자상수 c는 12.622

로 이루어짐을 알 수 있었다. 확대된 오른쪽 (440)면과 (224)면의 피크는 Voigt function을 사용하여 피팅(fitting)하면 pt2 계산 값과 일치하는 것을 확인할 수 있었다.The same VESTA program (http://jp-minerals.org /vesta/en/) was used to generate a calculated XRD pattern of the pt2 crystal phase, and the lattice constant was adjusted with experimental data. The lattice constant a of the pt2-Cd ₃ As _{2 nanowire prepared in Example 3 was 8.994.}

and the lattice constant c is 12.622

was found to be made of When the enlarged right (440) and (224) peaks were fitted using the Voigt function, it was confirmed that the pt2 calculated values were consistent with each other.

From the X-ray diffraction data of FIG. 4 , it was confirmed that the crystalline phase of the cadmium arsenide nanowire prepared in Example 3 was a second primitive tetragonal (pt2) crystalline phase.

Specifically, the diffraction angle 2θ of the (202) peak was measured to be 24.28°, the diffraction angle 2θ of the (400) peak was measured to be 40.07°, and the diffraction angle 2θ of the (224) peak was measured to be 40.23°.

In addition, the peaks of the bct crystal phase, the pt1 crystal phase, and the pt2 crystal phase are close to each other but have different relative intensities, and 2θ = 17.3°, 20.9°, 26.2°, 33.2°, 54.8° in the samples of the pt1 crystal phase and the pt2 crystal phase The (102)/(212), (201)/(214), (212)/(216), (302)/(326), (207)/(724) planes in It was found that relatively more peaks were included in the pt1 crystal phase and the pt2 crystal phase.

<Experimental Example> Scanning Electron Microscope (SEM) image analysis

5A is a scanning electron microscope (SEM) image of _{the pt1-Cd 3} As ₂ nanowire prepared in Example 2 above. Through the scanning electron microscope (SEM) image, _{it was confirmed that the pt1-Cd 3} As ₂ nanowires of Example 2 were synthesized in a uniform form on a silicon substrate in large quantities.

The length of the pt1-Cd ₃ As ₂ nanowire of Example 2 was 55 μm to 300 μm, and the average length was 150 μm.

<Experimental Example> Transmission Electron Microscope (TEM) image analysis

5B is a transmission electron microscope (TEM) image of _{the pt1-Cd 3} As ₂ nanowire prepared in Example 2 above. Through the transmission electron microscope (TEM) image, _{it was confirmed that the pt1-Cd 3} As ₂ nanowire of Example 2 had a smooth surface.

The average diameter of the pt1-Cd ₃ As ₂ nanowires of Example 2 was 130 nm.

<Experimental example> EDX measurement

5C is an energy-dispersive X-ray spectroscopy (EDX) element mapping result and a line profile analysis result of _{the pt1-Cd 3} As ₂ nanowire prepared in Example 2 above.

From the energy dispersive X-ray spectroscopy (EDX) element mapping image, it was confirmed that the cadmium element and the arsenic element constituting the cadmium arsenide nanowire were evenly distributed in the nanowire.

In addition, from the energy dispersive X-ray spectroscopy (EDX) spectrum analysis result, it can be confirmed that the molar ratio (Cd:As) of the cadmium element and the arsenic element constituting the cadmium _{arsenide (Cd 3} As _{2 ) nanowire is 3:2.} there was.

<Experimental Example> Correlation between unit lattice and crystallographic axis of cadmium arsenide nanowire

6 shows the correlation between the unit lattice and the crystallographic axis of _{the bct-Cd 3} As ₂ nanowire, pt1-Cd ₃ As ₂ nanowire, or pt2-Cd ₃ As ₂ nanowire prepared in Examples 1 to 3; the drawing shown.

6 shows the correlation between the unit lattice of bct, pt1, and pt2 and the crystallographic axis where [111]bct = [111]pt1 = [011]pt2, [221]bct = [221]pt1 = [021]pt2. The pt1 crystal phase has a lattice in the same direction as the bct crystal phase. The bct lattice constant is close to twice the value of the pt2 crystal phase, and the parameter a (= b) of the _bct unit lattice is diagonal to the pt2 unit lattice, and a bct = a _pt2 . Therefore, the [111]bct and [221]bct axes correspond to [011]pt2 and [021]pt2, respectively.

Here, the space group of the bct-Cd ₃ As _{2 nanowire is I4 1} /acd or I4 ₁ cd.

In addition, a space group of the pt1-Cd ₃ As _{2 nanowire is P4 2} /nbc.

In addition, a space group of the pt2-Cd ₃ As _{2 nanowire is P4 2} /nmc.

<Experimental example> bct-Cd ₃ As ₂ nanowire TEM FET image and SAED pattern analysis of crystal growth direction and crystal phase

7 is an FFT (Fast Fourier Transform) image and SAED (Selected Area Electron Diffraction) pattern obtained by analyzing the crystal growth direction and crystal phase of the bct-Cd ₃ As _{2 nanowire prepared in Example 1 with a transmission electron microscope (TEM).} . The same SAED pattern and FFT image were generated for the entire bct-Cd ₃ As ₂ nanowire, and single crystal characteristics were confirmed from the point-shaped diffraction points.

이다.7, the crystal growth direction of the bct-Cd ₃ As _{2 nanowire of Example 1 is}

am.

<Experimental example> pt1-Cd ₃ As ₂ nanowire TEM FET image and SAED pattern analysis of crystal growth direction and crystal phase

8 is a Fast Fourier Transform (FFT) image and a Selected Area Electron Diffraction (SAED) pattern obtained by analyzing the crystal growth direction and crystal phase of the pt1-Cd ₃ As _{2 nanowire prepared in Example 2 with a transmission electron microscope (TEM).} . The same SAED pattern and FFT image were generated for the entire pt1-Cd ₃ As ₂ nanowire, and single crystal characteristics were confirmed from the point-shaped diffraction points.

이다.8, the crystal growth direction of the pt1-Cd ₃ As _{2 nanowire of Example 2 is}

am.

<Experimental example> pt2-Cd ₃ As ₂ nanowire TEM FET image and SAED pattern analysis of crystal growth direction and crystal phase

9 is an FFT (Fast Fourier Transform) image and SAED (Selected Area Electron Diffraction) pattern obtained by analyzing the crystal growth direction and crystal phase of the pt2-Cd ₃ As _{2 nanowire prepared in Example 3 with a transmission electron microscope (TEM).} . The same SAED pattern and FFT image were generated for the entire pt2-Cd ₃ As ₂ nanowire, and single crystal characteristics were confirmed from the point-shaped diffraction points.

9, the crystal growth direction of the pt2-Cd ₃ As _{2 nanowire of Example 3 is [100] pt2} .

As described above in detail a specific part of the content of the present invention, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. something to do. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (21)

Cadmium arsenide nanowire, a Dirac semimetal compound. According to claim 1,
The nanowire is a single crystal (single crystal) characterized in that
Cadmium Arsenide Nanowires. According to claim 1,
The crystalline phase of the nanowire is a weight-centered tetragonal (bct) crystalline phase, a first tetragonal (pt1) crystalline phase, or a second primordial tetragonal (pt2) crystalline phase.
Cadmium Arsenide Nanowires. 4. The method of claim 3,
In XRD analysis of the body-centered tetragonal (bct) crystalline nanowire, the diffraction angle 2θ of the (224) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (408) peak is 40.0° to 40.3°, (440) ) The diffraction angle 2θ of the peak is characterized in that it appears at 40.1 ° to 40.4 °
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The weight-centered tetragonal system (bct) crystalline nanowire space group (space group) is I4 ₁ /acd or I4 ₁ cd, characterized in that
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The lattice constant a of the weight-centered tetragonal (bct) crystalline nanowire is 12.665 Å, and the lattice constant c is 25.443 Å.
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The crystal growth direction of the weight-centered tetragonal (bct) crystal phase nanowire is

characterized by
Cadmium Arsenide Nanowires. 4. The method of claim 3,
In XRD analysis of the first primitive tetragonal (pt1) crystalline nanowire, the diffraction angle 2θ of the (224) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (408) peak is 40.0° to 40.3°, ( 440) The diffraction angle 2θ of the peak is characterized in that it appears at 40.1 ° to 40.4 °
Cadmium Arsenide Nanowires. 4. The method of claim 3,
A space group of the first primitive tetragonal (pt1) crystalline nanowire is P4 ₂ /nbc
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The lattice constant a of the first primitive tetragonal (pt1) crystalline nanowire is 12.662 Å, and the lattice constant c is 25.452 Å.
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The crystal growth direction of the first primitive tetragonal (pt1) crystalline nanowire is

characterized by
Cadmium Arsenide Nanowires. 4. The method of claim 3,
In XRD analysis of the second primitive tetragonal (pt2) crystalline nanowire, the diffraction angle 2θ of the (202) peak is 23.9° to 24.6°, and the diffraction angle 2θ of the (400) peak is 39.9° to 40.2°, ( 224) The diffraction angle 2θ of the peak is characterized in that it appears at 40.1 ° to 40.4 °
Cadmium Arsenide Nanowires. 4. The method of claim 3,
A space group of the second primitive tetragonal (pt2) crystalline nanowire is P4 ₂ /nmc
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The lattice constant a of the second primitive tetragonal (pt2) crystalline nanowire is 8.994 Å, and the lattice constant c is 12.622 Å.
Cadmium Arsenide Nanowires. 4. The method of claim 3,
The crystal growth direction of the second primitive tetragonal (pt2) crystalline nanowire is [100] _pt2 ,
Cadmium Arsenide Nanowires. According to claim 1,
The nanowire has a diameter of 60 nm to 200 nm, and the length of the nanowire is 55 μm to 300 μm.
Cadmium Arsenide Nanowires. According to claim 1,
Cadmium element and arsenic element constituting the nanowire are uniformly distributed in the nanowire.
Cadmium Arsenide Nanowires. Preparing an electric furnace consisting of cadmium arsenide powder, a silicon substrate on which a gold thin film is deposited, and a two-stage (one-phase and two-phase) reactor capable of temperature control;
putting the cadmium arsenide powder into the ceramic boat and then placing it in the single-phase reactor, and placing the gold thin film-deposited silicon substrate in the two-phase reactor at a distance of 15 cm to 25 cm from the ceramic boat;
An inert gas of argon gas or nitrogen gas is supplied into the electric furnace at 200 to 800 sccm (standard cubic centimeter per minute) for the reaction time, and the temperature of the cadmium arsenide powder placed in the one-phase reactor is 350 ° C. to 800 ° C., obtaining a compound by synthesizing for 5 minutes to 3 hours while maintaining the temperature of the gold thin film deposition silicon substrate placed in the two-phase reactor at 250° C. to 600° C.; and
A method for producing a cadmium arsenide nanowire comprising the step of slowly cooling the compound to room temperature to obtain a single crystalline cadmium arsenide nanowire. 20. The method of claim 19, wherein the molar ratio (Au:Cd) of gold in the silicon substrate on which the gold thin film is deposited and cadmium in the cadmium arsenide powder is 1:1 to 1:3. Way. An electrical and electronic device manufactured including the cadmium arsenide nanowire according to any one of claims 1 to 18. The electrical/electronic device of claim 21, wherein the electrical/electronic device includes a magnetic sensor, an optical sensor, a superconductor, a spintronic device, or a quantum computer device.

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