KR100566566B1 - Nozzle beam nanoparticle generation method and generation device using ion seed - Google Patents

Abstract

The present invention relates to a method and apparatus for generating nozzle beam nanoparticles using an ion nucleus, and more particularly, to a method for generating metal nanoparticles using a nozzle beam vapor phase synthesis method, comprising: heating a metal to generate metal vapor, and corona discharge. Ionizing the argon gas through the ion and the generated ions act as a nucleus, characterized in that consisting of the step of generating metal nanoparticles by metal vapor condensation. In addition, the present invention is a metal nanoparticle generating apparatus by the nozzle beam vapor phase synthesis method evaporation chamber for generating metal vapor, corona discharge device for ionizing argon gas and metal nanoparticles generated by condensation of generated ions and metal vapor The present invention relates to a nozzle beam nanoparticle generator using an ion nucleus, characterized in that it is composed of an attachment chamber to be attached. According to the method and apparatus for generating a nozzle beam nanoparticle using the ion nucleus according to the present invention, it is possible to increase the monodispersity of nanoparticles compared to conventional nanoparticle vapor phase synthesis by homogenous condensation, and to achieve electrical control without changing thermodynamic conditions. By controlling the concentration of the ion nucleus through a more efficient and economical way to control the particle properties, thereby achieving the effect that can favor the mass production of metal nanoparticles.

Ion nuclei, nozzle beams, nanoparticles, homogeneous condensation, heterogeneous condensation, corona discharge, vapor phase synthesis, metal vapor, emission currents, patterning, aerosol etching, thin films, coatings.

Description

NOZZLE BEAM NANOPARTICLE GENERATION METHOD AND GENERATION DEVICE USING ION SEED}

1 is a schematic diagram of an apparatus for generating nozzle beam nanoparticles using an ion nucleus according to the present invention.

Figure 2 is a process diagram of a method for producing nozzle beam nanoparticles using an ion nucleus according to the present invention.

3 is a graph showing the change rate of metal vapor generation according to the temperature change of the furnace according to Experimental Example 1 of the present invention.

4 is a graph illustrating changes in emission current according to applied voltage change during corona discharge according to Experimental Example 2 of the present invention.

Figure 5a is an electron microscope (TEM) photograph of the nanoparticles produced during heterogeneous condensation according to Example 1 of the present invention.

5B is an electron microscope (TEM) photograph of nanoparticles generated during homogeneous condensation according to a comparative example of the present invention.

6 is a particle size distribution diagram of nanoparticles produced by Example 1 and Comparative Example of the present invention.

FIG. 7A is an electron micrograph (SEM) photograph of nanoparticles generated at an emission current of 0.41 mA according to Example 2 of the present invention. FIG.

7B is an electron micrograph (SEM) of the nanoparticles generated at the emission current of 0.61 mA according to Example 2 of the present invention.

7C is an electron micrograph (SEM) photograph of the nanoparticles produced at a 0.72 mA emission current according to Example 2 of the present invention.

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

10: evaporation chamber

11: as

12: tungsten electrode

13: linear motion device

20 corona discharge device

21: supersonic nozzle

22: high voltage supply

30: attachment chamber

31: attachment device

32: shutter

The present invention relates to a method and apparatus for generating nozzle beam nanoparticles using an ion nucleus, and more particularly, heating a metal to generate metal vapor, ionizing argon gas through a corona discharge, and generating the ion. Method of producing a nozzle beam nanoparticle using an ion nucleus, an evaporation chamber for generating metal vapor, and a corona discharge device for ionizing argon gas And an attachment chamber to which the metal nanoparticles generated by condensation of the generated ions and the metal vapor are attached.

In general, a gas phase synthesis method, which is one of physical manufacturing methods for producing metal nanoparticles, is a method of obtaining nanopowders by applying high energy such as heat or electron beam to a target metal to dissolve it, and then evaporating and condensing it. The nozzle beam method, which is one of vapor phase synthesis methods, has many applications such as thin film and coating, electronics, materials, and mechanical industries because the generated particles appear in the form of a beam. In this method, the generation of particles is greatly influenced by the degree of supersaturation inside, so that the control of temperature and pressure controls the characteristics of generated particles. In order to control the particle diameter of the generated particles, the temperature, atmosphere, type of gas, and pressure of the evaporation source are changed. Particles produced by this method have the advantages of high purity, uniform particle size, and easy control of particle size, but low yield, low production rate, and continuous mass production are difficult. have.

In gas phase synthesis, first, a metal gas from the molten metal must be condensed to generate a nucleus for generating particles. When such nucleation process is produced by its supersaturation degree, it is called homogeneous condensation, and when nuclear is injected from outside, it is called heterogeneous condensation. The generation of metal nanoparticles in homogenous condensation, unlike other materials, requires a high degree of supersaturation for nucleation due to the high nucleation barrier and surface tension of the metal, requiring high heat of vaporization and extremely low pressure. For this reason, in conventional homogeneous condensation, energy consumption is severe and economical is not good.

In order to solve this problem, the introduction of active nuclear concentration control, which is an advantage of heterogeneous condensation, eliminates the need for relatively high degree of supersaturation for nucleation. In particular, the primary goal of studies related to particle generation is to lower the geometric mean dispersion, which represents the degree of monodispersity, which is generally superior to particles produced through heterogeneous condensation rather than particles produced through homogenous condensation. It is known.

The present invention is to solve the problems of the method for producing metal nanopowder by the conventional vapor phase synthesis method as described above by adjusting the characteristics of the particles generated by injecting ions as a nucleus for the production of nanoparticles and controlling the concentration of ions Instead of thermodynamic particle property control method, the technical problem is to achieve more economical and efficient electric particle property control method and to utilize functional nano particle manufacturing process and particle beam deposition, thin film and coating.

An object of the present invention as described above is to heat the metal to generate metal vapor, to ionize the argon gas through a corona discharge and to the step of generating the metal nanoparticles by the condensation of the metal vapor by the generated ions nucleus It can be achieved by a method for producing a nozzle beam nanoparticles using an ion nucleus, characterized in that made,

In addition, the object of the present invention as described above consists of an evaporation chamber for generating metal vapor, a corona discharge device for ionizing argon gas, and an attachment chamber to which metal nanoparticles generated by condensation of the generated ions and metal vapor are attached. It can be achieved through a nozzle beam nanoparticle generating device using an ion nucleus characterized in that.

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

1 is a schematic diagram of a nozzle beam nanoparticle generating apparatus using an ion nucleus according to the present invention, and FIG. 2 is a process diagram of a method of generating nozzle beam nanoparticles using an ion nucleus according to the present invention. 3 to 8 are graphs and photographs showing the results of experiments using the nozzle beam nanoparticle generating apparatus using the ion nucleus according to the present invention.

First, the configuration of the nozzle beam nanoparticle generating apparatus using the ion nucleus according to the present invention will be described based on the bar shown in FIG. 1.

The nozzle beam nanoparticle generating apparatus using the ion nucleus according to the present invention includes an evaporation chamber 10 for producing metal vapor, a corona discharge device 20 for supplying ions injected into the condensation nucleus from heterogeneous condensation, and homogeneous And a deposition chamber 30 for attaching nanoparticles generated through condensation or heterogeneous condensation.

The evaporation chamber 10 is equipped with a small furnace 11 for generating metal steam and a tungsten electrode 12 for corona discharge. The tungsten electrode is attached with a circular supersonic nozzle 21 connected between the evaporation chamber 10 and the attachment chamber 30 and a linear motion device 13 to maintain a proper length.

The furnace 11 for generating metal vapor is in the form of a tungsten wire basket as a heating element around an alumina furnace having a capacity of 6 cc. The furnace 11 for the generation of metal steam can be supplied up to about 5V, up to 150A, and is equipped with a temperature controller 14 that can raise the temperature up to 1300 degrees.

The overall size of the evaporation chamber 10 is a stainless steel cylindrical structure having an inner diameter of about 100 mm, a thickness of 3 mm, and a width of 370.5 mm, and is equipped with a K-type thermocouple sensor for measuring the temperature of the inner wall and the outer wall of the chamber, respectively. A port for ionizing gas is attached.

The evaporation chamber is connected to a port to which the rotary pump 15 can be connected for pressure control independent of the attachment chamber and a pressure sensor for measuring the pressure inside the chamber. In addition, the furnace is surrounded by a heat insulating material around the chamber, and a furnace for independently controlling the internal temperature is attached, and a port for injecting argon gas is provided.

The corona discharge device 20 is a tungsten electrode 12 of the evaporation chamber 10 and a supersonic nozzle 21 connected between the evaporation chamber 10 and the attachment chamber 30 and a high voltage supply for applying a voltage ( 22).

The supersonic nozzle 22 is made of a conductive stainless steel material so that the tungsten electrode 12 and the corona discharge can be generated, and anodized on both sides of the nozzle for insulation between the nozzle and the chamber. , t = 100 μm) treated aluminum plate. The nozzle 22 is a circular nozzle with a nozzle neck of 0.5 mm in diameter and an expansion ratio of 20: 1.

Corona discharge occurs between the tungsten electrode 12 and the nozzle 21, and the linear motion device 13 is capable of adjusting the distance between the tungsten electrode 12 and the nozzle 21 to a minimum scale of 1/50 inch. It is mounted on the (12) side. A voltage can be applied between the tungsten electrode 12 and the nozzle 21 using the high voltage supply 22, and a digital multimeter for measuring the total current is provided between the tungsten electrode 12 and the high voltage supply 22. It is connected. A digital multimeter is connected to measure the loss current flowing through the nozzle 21, and by obtaining the difference between the total current and the loss current, it is possible to obtain the emission current delivered to all the generated particles. In addition, the tungsten electrode was able to move in an alumina tube having an inner diameter of 4 mm, a thickness of 1 mm, and a width of 230 mm so as to be insulated from the outside.

The attachment chamber 30 is attached to the attachment device 31 on which the TEM grid can be placed to analyze the generated particles, and a shutter 32 is attached between the nozzle 21 and the attachment device to collect in a steady state. Made it possible.

The attachment chamber 30 has a cylindrical structure having an inner diameter of 300 mm and a width of 313.4 mm, and has three observation ports attached to it so that it can look inside. A K-type thermocouple sensor for measuring the internal temperature is attached, and a diffusion pump 33 for high vacuum is connected. There is also a thermocouple sensor for measuring the internal pressure. Inside the chamber is a device that can capture and analyze the generated particles.

A shutter 32 for collecting particles in the steady state was mounted between the attachment device 31 and the nozzle 21. The attachment device 31 is located 100mm away from the nozzle 21, and a 3mm diameter groove having a diameter of 3mm is formed at 3mm intervals so as to attach up to four TEM grids to the stainless rod. The particle collection rod is also wrapped in a stainless steel tube with a diameter of 3 mm and a hole perforated parallel to the nozzle center, allowing it to be collected for each condition and equipped with a linear mover that can move up and down. In addition, a power supply line for attaching the electric line of the nozzle 21 to the high voltage supply 22 outside the chamber is attached.

In the method of generating nanoparticles using a nozzle beam nanoparticle generating apparatus using an ion nucleus, as shown in FIG. 2, the method generates a metal vapor by heating a metal (S100). The argon gas injected into the evaporation chamber is corona discharged through a corona discharge. The ionization step (S200) and the generated ions become a nucleus and the metal vapor is condensed to produce the metal nanoparticles (S300).

The amount of metal vapor generated in the metal vapor generating step (S100) may be controlled by changing the temperature of the furnace 11, thereby affecting various characteristics such as the number, concentration, particle size distribution, and crystal phase of the metal particles passing through the supersonic nozzle. Can give

Experimental Example 1 Metal Vapor Generation

Metal vapor generation was measured by varying the temperature of the furnace 11 at a fixed pressure ratio across the chamber. The pressure of the evaporation chamber was fixed at 2.5torr and the pressure of the attachment chamber at 0.015torr, and the temperatures of the furnace containing the silver powder were changed to 970 ° C, 1000 ° C and 1030 ° C, respectively. The evaporation time of silver vapor was measured by giving an evaporation time of about one hour and measuring the mass of silver before and after the experiment. A graph showing the evaporation rate according to temperature is shown schematically in FIG. 3. It can be seen that as the temperature of the furnace 11 increases, the amount of generated metal vapor increases.

Under low pressure conditions in which the flow applying the corona discharge flows in the step S200 of ionizing the argon gas through the corona discharge, some of the ions generated from the entire corona discharge flow out of the nozzle together with the flow out of the nozzle. It acts as a nucleus, causing heterogeneous condensation. At this time, it is possible to control the concentration of ions acting as a condensation nucleus by adjusting the applied voltage.

Experimental Example 2 Corona Discharge Experiment

The internal pressure of the evaporation chamber was fixed at 2.5 torr and the corona discharge characteristics were measured at an electrode spacing of 5.29 mm. 4 shows a graph of the emission current according to the applied voltage. By applying a corona discharge, the concentration of ions was adjusted according to the applied voltage, which becomes the relative condensation nuclear concentration in heterogeneous condensation. It can be seen that the concentration of ions increases as the emission current increases as the applied voltage increases.

Hereinafter, the contents of the present invention will be described in detail through examples and comparative examples related to the present invention.

Example 1

The pressures of the evaporation chamber and the attachment chamber were fixed at 2.4torr and 0.016 torr, respectively, and the furnace temperature was fixed at 1030 ° C. At this time, a voltage was applied for heterogeneous condensation so that the emission current was controlled to 0.41 ㎂. Electron microscopy (TEM) photographs of the particles thus obtained are illustrated in FIG. 5A and the particle size distribution is illustrated in FIG. 6.

The average particle diameter of the particles obtained by heterogeneous condensation through the ion nucleus of Example 1 was 12 nm, and the standard deviation was found to be 4.15.

Comparative example

Except that no voltage was applied in Example 1, the electron microscope (TEM) photograph of the obtained particles was plotted in FIG. 5B, and the particle size distribution was shown in FIG. 6 along with the results of Example 1. .

The average particle diameter of the particles obtained by homogeneous condensation of the comparative example was 16 nm, and the standard deviation was found to be 5.67.

When comparing the results of Example 1 and Comparative Example it can be seen that in the case of the method for producing nanoparticles by heterogeneous condensation according to the present invention, the particles have a smaller average particle diameter and more even particles are produced.

Example 2

In order to observe the properties of the particles produced by changing the concentration of ions under the same thermodynamic conditions, the pressures of the evaporation chamber and the adhesion chamber were fixed at 2.7torr, 0.017torr, and furnace temperature at 1030 ℃ and the voltage of corona discharge was increased. Particles were generated by varying the emission current to 0.41, 0.61 and 0.7 mA, respectively. In FIG. 7, electron microscope (SEM) photographs of nanoparticles generated by respective emission currents are illustrated. Table 1 shows average particle diameters and standard deviations of nanoparticles according to emission currents.

Emission current 0.41 0.61 0.72 Average particle diameter (nm) 25 18 16 Standard deviation (nm) 11 (44%) 7 (39%) 5 (31%)

The value of the emission current represents the relative concentration of the total supplied ions. As shown in FIG. 7 and Table 1, as the value of the emission current increases, the average particle diameter and the standard deviation decrease, and the number concentration of the particles increases relatively. This indicates that ions implanted into the condensation nucleus acted as the dominant production mechanism in particle generation rather than nucleation by homogenous condensation. As the concentration of ions increases, the number of particles also increases, but there is almost no aggregation because the electrical repulsive force is applied by the initial charge by the ions, thereby reducing the aggregation.

According to the method and apparatus for generating a nozzle beam nanoparticle using the ion nucleus according to the present invention, it is possible to increase monodispersity of nanoparticles compared to conventional nanoparticle vapor phase synthesis by homogenous condensation, and to achieve electrical control without changing thermodynamic conditions. By controlling the concentration of the ion nucleus through a more efficient and economical way to control the particle properties, thereby achieving the effect that can favor the mass production of metal nanoparticles.                     

The method and apparatus for generating nozzle beam nanoparticles using the ion nucleus according to the present invention can be used for particle beam patterning, aerosol etching, thin films and coatings in semiconductor processes.

Although the invention has been described with reference to the preferred embodiments mentioned above, many other possible modifications and variations can be made without departing from the spirit and scope of the invention. Accordingly, the appended claims are intended to cover such modifications and variations as fall within the true scope of the invention.

Claims (9)

In the method for producing metal nanoparticles by the nozzle beam vapor phase synthesis method, Applying a vacuum in the evaporation chamber and heating the metal in the furnace to generate metal vapor (S100), Ionizing argon gas injected into the evaporation chamber through corona discharge (S200) and The method of generating a nozzle beam nanoparticle using an ion nucleus, characterized in that the ion generated through the corona discharge becomes a nucleus and condenses in a vacuum attachment chamber together with metal vapor to generate metal nanoparticles (S300). . The method according to claim 1, wherein the amount of metal vapor generated in the step of generating metal vapor by heating the metal in the furnace in the evaporation chamber (S100) can be controlled by changing the temperature of the heating furnace. Nozzle beam nano particle generation method. The ion nucleus of claim 1, wherein the concentration of ions generated in the ionization of the argon gas through the corona discharge (S200) can be changed by changing the emission current by adjusting the voltage of the corona discharge. Nozzle beam nanoparticle generation method using. The method of claim 1, wherein the metal is silver, the pressure of the evaporation chamber is 2.7torr, the pressure of the attachment chamber is 0.017torr and the temperature of the furnace in the evaporation chamber is 1030 ℃, the discharge current during the corona discharge is Nozzle beam nanoparticle generation method using an ion nucleus, characterized in that 0.41 ~ 0.7 GHz In the apparatus for producing metal nanoparticles by the nozzle beam vapor phase synthesis method Evaporation chamber 10 for generating metal vapor, Installed in the evaporation chamber 10, the corona discharge device 20 for ionizing the argon gas in the evaporation chamber 10 and Connected to one end of the evaporation chamber 10, the metal vapor generated in the evaporation chamber 10 and the adhesion chamber 30 is attached to the metal nanoparticles generated by condensation of ions generated in the corona discharge device 20 to the attachment chamber 30 Nozzle beam nanoparticle generator using an ion nucleus, characterized in that configured. The evaporation chamber (10) of claim 4, wherein the evaporation chamber (10) comprises a furnace (11) for heating a metal equipped with a thermostat (14), a tungsten electrode (12) for corona discharge, the tungsten electrode (12) and a supersonic nozzle ( 21. A nozzle beam nanoparticle generator using an ion nucleus, characterized in that it comprises a linear motion device (13) for adjusting the distance from the pump and a pump (15) for pressure control in the evaporation chamber (10). The supersonic nozzle (21) of claim 4, wherein the corona discharge device (20) is connected between the tungsten electrode (12) of the evaporation chamber (10) and the evaporation chamber (10) and the attachment chamber (30). And a high voltage supply (22) for applying a voltage between the tungsten electrode (12) and the supersonic nozzle (21). 5. The deposition chamber (30) according to claim 4, wherein the attachment chamber (30) is an attachment device (31) to which condensed metal particles are attached, a shutter (32) for collection in a steady state, and a diffusion pump for high vacuum in the attachment chamber (30). Nozzle beam nanoparticle generator using an ion nucleus, characterized in that consisting of (33). 7. The nozzle beam nanoparticle generator using ion nuclei according to claim 6, wherein the supersonic nozzle 21 is fixed and the tungsten electrode 12 is attached to the linear motion device 13 to enable linear motion. .

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