WO2014148727A1

WO2014148727A1 - Multi-spark discharge generator and method for manufacturing nanoparticle structure using same

Info

Publication number: WO2014148727A1
Application number: PCT/KR2013/011884
Authority: WO
Inventors: 최만수; 하경연; 최호섭; 한규희; 정기남; 이동준; 채석병
Original assignee: 재단법인 멀티스케일 에너지시스템 연구단; 서울대학교산학협력단
Priority date: 2013-03-22
Filing date: 2013-12-19
Publication date: 2014-09-25

Abstract

The present invention relates to a spark discharge generator, and the spark discharge generator according to the present invention comprises a plurality of column-type electrodes and a grounding plate having a plurality of exit holes in positions corresponding to positions of respective column-type electrodes, thereby making it possible to manufacture a large-area nanostructure array with a three-dimensional shape uniformly and rapidly.

Description

Multi-spark discharge generator and nanoparticle structure manufacturing method using the same

The present invention relates to a spark discharge generator and a method for producing a nanoparticle structure using the same.

Nano-patterning technology, which produces micro- and nano-scale structures by selectively controlling charged nanoparticles and depositing them in the desired location, is a quantum device and nanobio that will be the key to the next generation of industries. It is expected to be useful for the development of nanobio devices.

As one example of a patterning technique of such charged nanoparticles, a method of depositing charged nanoparticles having opposite polarities after charging a substrate using an electron beam or an ion beam is known. However, this method is not only time-consuming because the method of charging the substrate is in series, but also has a limitation that it can be used only when the substrate is a non-conductor because the surface of the substrate is charged using an electron beam or an ion beam.

In addition, after forming a photoresist (photoresist) on the support and a pattern by using a photolithography (photolithography), etc., the technique of inducing and depositing only the charged nanoparticles in the pattern using the electrostatic force without the ion accumulation process This is known. However, the technique can pattern high-purity nanoparticles generated in a gaseous state, but does not accumulate ions on the photoresist pattern, so that a large number of nanoparticles are deposited not only on an electrically conductive substrate but also on an undesired location, that is, on the photoresist surface. Can be.

Spark discharge is an efficient method for generating nano-sized particles among various gas phase synthesis methods and is useful for assembling nanostructures by generating charged aerosols with simple equipment. There are many ways of spark discharge, among which rod-to-rod method has been widely used. This approach has recently been used for the synthesis of double or mixed metal nanoparticles or for nanowire growth. Spark discharge generators are known to generate nano-sized particles, but charged aerosols of less than 10 nm tend to produce electrostatic aggregation of bipolar nanoparticles. It is important to generate such anti-agglomeration and smaller size charged aerosols in the spark discharge generator.

Methods of adjusting operating parameters such as spark frequency, spark energy and flow rate of carrier gas are also known to reduce the agglomeration of particles in a spark discharge generator.

As part of this effort, the present applicant has proposed a method for producing a two-dimensional or three-dimensional nanoparticle structure by focusing patterning of nanoparticles in Korean Patent Application Publication No. 10-2009-0089787 (published Aug. 24, 2009). There is a bar. The method simultaneously combines nanoparticles and ions that are bipolarly charged by spark discharge of an electrode structure of pin-to-plate or tip-to-plate structure. After generation, the nanoparticle structure having a two-dimensional or three-dimensional shape can be efficiently manufactured regardless of the polarity of the nanoparticles or ions by injecting into the reactor in which the patterned substrate is present and applying an electric field.

The pin-to-plate or tip-to-plate structure has an asymmetrical structure consisting of a pin with a sharp tip as the anode and a ground plate with a central outlet. . Charged aerosols produced by such pin-to-plate structures are known to have a much smaller particle size, less agglomeration and a narrower particle size distribution than rod-to-rod structures.

However, the fin-to-plate structure, which has been studied so far, can form nanostructures only in a limited area, for example, an area of about 8 mm or less in diameter, so that a large area and a high speed are necessary for industrialization.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Korean Patent Application Publication No. 10-2009-0089787 (published Aug. 24, 2009)

Accordingly, an aspect of the present invention is to provide a spark discharge generator capable of uniformly forming nanostructures at high speed in a large area and a method of manufacturing nanostructures using the same.

The present invention to achieve the above object

A discharge chamber having a gas inlet and an outlet,

A plurality of columnar electrodes located in the discharge chamber,

A ground plate located in the discharge chamber and having a plurality of outlet holes at positions corresponding to the positions of the respective columnar electrodes,

A spark discharge generator having a substrate support in a position opposite to the columnar electrode and the ground plate is provided.

According to a preferred embodiment of the present invention, the columnar electrode may have a sharp, round or flat shape in the distal end portion facing the outlet hole of the ground plate.

In addition, the distal end of the columnar electrode may be spaced a predetermined distance from the outlet hole of the ground plate, at the same position as the outlet hole, or penetrate the outlet hole.

By controlling the outlet hole diameter of the ground plate, the outlet flow rate of the spark discharge generator may be adjusted to control the degree of aggregation of the particles.

According to a preferred embodiment of the present invention, the gas inlet may be further provided with a corona discharger.

According to a preferred embodiment of the present invention, the terminal portion of the columnar electrode can generate ions simultaneously with particle generation.

According to a preferred embodiment of the present invention, it is possible to control the distance between the ground plate and the substrate support, and also provided with an internal cylinder to adjust the gas inlet flow rate at the gas inlet, by using this to control the degree of aggregation of particles Can be.

The spark discharge generator according to the present invention preferably uses a circuit composed of a plurality of resistors and a plurality of capacitors as a constant high voltage source.

In addition, the reaction chamber is preferably provided with a window for viewing the spark discharge state.

The present invention also provides a method for uniformly forming a large area of a three-dimensional nanostructure array using a spark discharge generator as described above.

The spark discharge generator according to the present invention is provided with a ground plate having two or more columnar electrodes and a corresponding plurality of outlet holes, so that particles are sprayed in a large area. Therefore, a large amount of particles can move quickly along the electric field formed in the entire area of the large-area substrate, so that nanostructures can be rapidly produced on the large-area substrate, and thus, nanostructure arrays of industrially applicable scale can be manufactured by spark discharge. Can be.

1 is a schematic diagram of a spark discharge device according to a preferred embodiment of the present invention.

2 schematically illustrates the shape of an end portion of a columnar electrode according to various embodiments of the present disclosure.

3 schematically illustrates the relative positions of columnar electrodes and ground plate outlet holes in accordance with various embodiments of the present invention.

4 is a nanostructure array sample image (a) and SEM image thereof (b) formed in a large area in accordance with an embodiment of the present invention.

5 is a result of measuring the size deviation according to the substrate position of the nanostructure array manufactured according to an embodiment of the present invention.

6 is an SEM image of an array of nanostructures formed in a large area using a single-spark discharge generator according to a comparative example.

7 is a result of measuring the size deviation according to the position of the substrate of the nanostructure array manufactured according to the comparative example.

Figure 8 is a photograph comparing the structure shape according to the flow rate in the multi-spark method according to the present invention (opening diameter of the photosensitive film is 2 microns).

9 is a graph showing the particle size distribution according to the flow rate in the multi-spark method according to the present invention.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

1 is a schematic diagram of a device according to a preferred embodiment of the present invention.

As shown in FIG. 1, the spark discharge device according to the present invention is characterized by having a ground plate having a plurality of columnar electrodes and a plurality of outlet holes corresponding to each columnar electrode.

The columnar electrode covers the pin electrode, the wire electrode, and the rod electrode, and the shape thereof is not particularly limited.

In addition, although the distal end shape of the columnar electrode is illustrated as a sharp pin electrode in FIG. 1, the present invention is not limited thereto. Specifically, as shown in FIG. 2, the distal end of the columnar electrode may be sharp (a) round (b) or flat (c).

In addition, the diameter, length, and the like of the columnar electrode are not particularly limited and can be appropriately adjusted according to the application field or use.

For example, the diameter of the pin electrode may be, for example, several microns to several millimeters, for example, 0.01 to 20 mm, but is not limited thereto. In addition, the radius of curvature of the distal tip portion may be several microns to several millimeters, for example, 0.01 mm or more, but is not limited thereto.

The outlet holes of the ground plate are formed to correspond to the respective columnar electrodes and may have diameters of several microns to several millimeters, for example, 0.1-25 mm, but are not limited thereto. By controlling the outlet hole diameter of the ground plate, the outlet flow rate of the spark discharge generator may be adjusted to control the degree of aggregation of the particles.

The distance between the columnar electrode and the ground plate is not particularly limited.

As shown in FIG. 3, the columnar electrode 10 and the ground plate 20 are spaced a predetermined distance apart (a) or at the same position (b) or the outlet where the columnar electrode 10 is formed on the ground plate 20. (C) may be located through the hole (30).

As shown in FIG. 3A, the columnar electrode 10 is spaced apart from the outlet hole 30 of the ground plate path 20 by, for example, several microns to several tens of millimeters, for example, 0.01-10 mm. But it is not limited thereto.

On the other hand, as shown in FIGS. 3B and 3C, when the columnar electrode 10 is inserted or penetrated at the same position as the outlet hole 30 of the ground plate 20 or through the outlet hole 30, the columnar electrode 10 is columnar. Make sure the electrodes do not touch the ground plate.

The number of the columnar electrodes may be advantageous to form nanostructures uniformly over the entire area of 1 to ³ per 20-50 mm ^2, but is not limited thereto.

The material of the columnar electrode and the ground plate is a nanoparticle precursor, a conductive material selected from gold, copper, tin, indium, ITO, graphite, and silver; Conductive material coated with an insulator material selected from cadmium oxide, iron oxide and tin oxide; Or a semiconductor material selected from silicon, GaAs, and CdSe, and is not particularly limited.

The electrical circuit for spark discharge is a constant high voltage source structure consisting of a high voltage source (HV), an external capacitor (C), and a resistor (R). Depending on the particle size can be adjusted separately, but is not limited thereto.

Method for manufacturing a nanostructure array using a spark discharger is disclosed in detail in Korean Patent Application Publication No. 10-2009-0089787, a detailed description thereof will be omitted. However, the apparatus of the present invention may further include a corona discharger for more efficient ion generation and deposition as shown in FIG. The corona discharger may be applied with a voltage in the range of 1 kV to 10 kV.

The flow rate of the carrier gas such as nitrogen, helium, and argon is controlled by the diameter of the ground plate outlet hole inserted into the reactor, which is a variable to control the aggregation of particles generated by the multi-spark.

The flow rate of the carrier gas such as nitrogen, helium and argon can be controlled by the diameter of the inner cylinder inserted into the reactor, which is a variable to control the aggregation of particles generated by the multispark.

The distal end of the columnar electrode is characterized by generating ions simultaneously with particle generation, which may affect the formation of the structure, and may be adjusted to be sharp, round or flat as necessary.

The device according to the present invention can adjust the spacing between the plate electrode and the sample (substrate) to control the uniformity of the large-area nanostructure array fabrication and the region in which the nanostructure is formed.

The position of the inlet of the gas flowing into the multi-spark discharge generator can be adjusted, thereby controlling the particle movement path. According to a preferred embodiment of the present invention, a plurality of gas inlets and outlets is advantageous for forming a uniform nanostructure on a large area substrate. Alternatively, the particle migration path can be controlled by adjusting the positions of the inlet and outlet.

In addition, the device according to the invention preferably has a window for viewing the spark discharge state, and the sample (substrate) is preferably located in the center of the chamber.

The device according to the invention can be conveniently used to form a three-dimensional array of nanostructures in a large area, for example 0.25 cm ² or more.

Hereinafter, specific embodiments of the present invention will be described, but these are only examples, and the scope of the present invention is not limited thereto.

Example 1

As illustrated in FIG. 1, an experiment was performed using a pin-to-plate spark discharger (example) equipped with a plurality of pin electrodes and a spark discharger (comparative example) provided with one tip.

The discharge chamber had a volume of 727 cm ³ , an inner diameter of 11.5 cm, and a height of 7 cm. The diameter of the pin electrode was 4 mm each, and 16 or more things with the radius of curvature of the terminal part were about 0.13 mm. The outlet hole of the ground plate is formed corresponding to each pin electrode and is 1 mm in diameter. Both the pin electrode and the ground electrode were made of copper, and the distance between both electrodes was 2.5 mm. Nitrogen gas was used as the carrier gas. The flow rate was 0.03 m / s.

The electrical circuit for spark discharge connected HV (Bertan 205B, maximum voltage 10kV) in series with the pin electrode through a 20 Mohm resistor. A 2 nF capacitor was connected in parallel to the electrode. HV voltage was tested while changing to 4kV, 5kV, 6kV. The corona discharger was operated at 4 kV.

Nanoparticles were deposited on a 6 cm x 6 cm silicon substrate on which a nanopattern was formed with a photoresist film with holes of 2 microns in diameter spaced at 4 micron intervals for 1 hour and 30 minutes.

The resulting nanostructure array sample image (a) and its SEM image (b) are shown in FIGS. 4 and 5 (HV voltage 4 kV).

Example 2

It carried out similarly to Example 1 except having set the nitrogen gas flow rate into 0.06 m / s.

Example 3

It carried out similarly to Example 1 except having set the nitrogen gas flow rate into 0.09 m / s.

Comparative Examples 1 to 3

Nanostructures were prepared in the same manner as in Examples 1-3 (nitrogen gas flow rate changes) except that a single tip was used.

Experiment result measurement

The size of the nanostructure was measured using a SMPS device composed of a differential mobility analyzer (DMA), a bipolar chargher, a flow control system, a condensation particle counter (CPC), and a data inversion system. The nanostructure arrays manufactured through the multi-tip spark generator were measured in shape and size by using a field-emission scanning electron microscope (SUPRA 55VP).

5 is a result of measuring the height and diameter distribution of the nanostructure obtained in Example 3 (voltage 4kV). In spite of the large area, it can be seen that both the vertical and horizontal directions have a uniform distribution.

7 is a result of measuring the size deviation according to the position of the substrate of the nanostructure array manufactured according to the comparative example. The further away from the center of the tip, the poorer the formation of the structure is, and thus there is no uniformity.

8 is an SEM image of the nanostructures obtained in Examples 1, 2 and 3 (voltage 4 kV). It can be seen that as the flow rate increases, particle aggregation decreases, resulting in a structure with a smooth surface.

Figure 9 is a data measuring the size distribution of the particles generated by varying the flow rate at a voltage of 4kV. It can be seen that as the flow rate increases, the aggregation of particles decreases and the number of large particles decreases. That is, it can be confirmed through FIG. 7 that the aggregation of the particles can be controlled at a flow rate.

Claims

A discharge chamber having a gas inlet and an outlet,

A plurality of columnar electrodes located in the discharge chamber,

A ground plate located in the discharge chamber and having a plurality of outlet holes at positions corresponding to the positions of the respective columnar electrodes,

A spark discharge generator having a substrate support at a position opposite to the columnar electrode and the ground plate.
The method of claim 1,

The columnar electrode having a distal end facing the outlet hole of the ground plate, wherein the distal end has a sharp, round or flat shape.
The method of claim 2,

And the distal end of the columnar electrode is spaced a predetermined distance from the outlet hole of the ground plate, at the same position as the outlet hole, or penetrates through the outlet hole.
The method of claim 1,

By adjusting the outlet hole diameter of the ground plate to adjust the flow rate of the outlet of the spark discharge generator to control the degree of aggregation of the spark discharge generator.
The method of claim 1,

And a corona discharger at the gas inlet.
The method of claim 1,

And a plurality of gas inlets and outlets, respectively, spark discharge generator.
The method of claim 2,

A spark discharge generator, wherein the terminal portion of the columnar electrode generates ions simultaneously with particle generation.
The method of claim 1,

The spark discharge generator that can adjust the distance between the ground plate and the substrate support.
The method of claim 1,

The gas inlet is provided with an internal cylinder that can adjust the gas inlet flow rate, it is possible to control the degree of aggregation of particles by using the spark discharge generator.
The method of claim 1,

Spark discharge generator, using a circuit composed of a plurality of resistors, a plurality of capacitors as a constant high voltage source.
The method of claim 1,

And the reaction chamber is provided with a window for viewing the spark discharge state.
12. A method of forming a three-dimensional array of nanostructures using the spark discharge generator of any one of claims 1-11.