KR20080113762A - Apparatus for analyzing specimen - Google Patents

Apparatus for analyzing specimen Download PDF

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Publication number
KR20080113762A
KR20080113762A KR1020070062621A KR20070062621A KR20080113762A KR 20080113762 A KR20080113762 A KR 20080113762A KR 1020070062621 A KR1020070062621 A KR 1020070062621A KR 20070062621 A KR20070062621 A KR 20070062621A KR 20080113762 A KR20080113762 A KR 20080113762A
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KR
South Korea
Prior art keywords
sample
electron beam
biprism
objective lens
hologram
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KR1020070062621A
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Korean (ko)
Inventor
양준모
유정호
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한국과학기술원
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Priority to KR1020070062621A priority Critical patent/KR20080113762A/en
Publication of KR20080113762A publication Critical patent/KR20080113762A/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45—Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods
    • G01N21/453—Holographic interferometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
    • G01N23/225—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion
    • G01N23/2251—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material using electron or ion using incident electron beams, e.g. scanning electron microscopy [SEM]

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

An apparatus for sample analysis is provided to minimize the shading effect due to the bi prism by using carbon nanotube and nanowire having thin diameter of a nano level. An apparatus for sample analysis comprises the field electrons layer, condensing lens(302), objective lens(305), bi prism, static power supply, hologram. The field electrons layer irradiate a electron beam by the field emission effect of the electronics(304). The condensing lens condenses the electron beam radiated from the field emission electron gun and irradiates the sample(303). The objective lens forms the enlargement phase of sample by the electron beam transmitted in sample. The bi prism uses a carbon nanotube(307) generating the interference fringe from the electron beam transmitted in the objective lens. The static power supply Supplies voltage to the bi prism. By using the interference fringe generated in the bi prism, hologram is formed.

Description

Sample analysis device {APPARATUS FOR ANALYZING SPECIMEN}

1 and 2 show a general transmission electron microscope for forming a hologram.

3 and 4 show the formation principle of the hologram by the biprism of the general transmission electron microscope.

5 and 6 are views showing a transmission electron microscope for forming a hologram using carbon nanotubes and nanowires according to an embodiment of the present invention.

***** Explanation of symbols for main parts of drawing *****

301,401: electron gun

302,402 condensing lens

303,403: sample

304,404: electron beam

305,405: objective lens

306,406: constant voltage supply

307,407: carbon nanotubes, nanowires

308,408: hologram recorder

The present invention relates to a sample analysis device. More specifically, the present invention relates to a biprism of a field emission-transmission electron microscope (FE-TEM).

A general transmission electron microscope is a microscope using an electron beam instead of a lens and an electron beam having properties similar to a light source instead of a light source of an optical microscope. The basic principle of imaging is the same as that of an optical microscope.

Here, since the electron beam is significantly larger in interaction with the material compared to the light beam, the thickness of the sample should be as thin as 1000 kHz and placed in a vacuum. Therefore, the transmission electron microscope is a device using the three light and dark generation principles of scattering absorption, diffraction, and phase generated when an electron beam passes through a sample.

First, when an electron beam is irradiated to the sample from the tank gun installed inside the transmission electron microscope, it is scattered in the sample, and then transmitted through the condenser lens to form a diffraction shape on the rear focal plane of the objective lens. That is, the electron beam scattered in a certain direction in the sample is collected at one point in the post focal plane.

Subsequently, a secondary wave gathered at a point in the post focal plane creates an enlarged image at the focus of the objective lens. This image is magnified and imaged on the fluorescent plate in the projection lens. Here, by adjusting the focal length between each lens, the microscope shape and the diffraction shape can be obtained as desired. The acquired images are recorded or preserved using a charged-coupled device (CCD) camera dynamically or recorded using various storage media, and processed and analyzed by an external image processing apparatus.

On the other hand, in the field emission-type transmission electron microscope (FIELD FE-TEM), an electron beam is emitted from a field emission gun. Such an electron beam is used for interference experiments of electromagnetic waves through a biprism installed inside a field emission transmission electron microscope. Thus, the phase information of the electrons passing through the inside of the specimen is reproduced using the interference image of the electron beam. Reproducing such phase information of electrons is called Electron Holography. Electron holography may reproduce a hologram image through a Fourier transform and may be divided into a phase image and an amplitude image.

Here, the phase image shows only the phase change that is changed by the characteristics of the sample, and shows the electrical and magnetic characteristics in the local region as a nano-scale image. Electron holography having such nano-resolution (Resolving Power) is generally applied to the evaluation of the electrostatic field and the magnetization distribution.

1 to 4 are diagrams showing the principle of hologram formation by a general transmission electron microscope and a biprism forming a hologram.

A general transmission electron microscope includes a plurality of lenses for transmitting an electron beam, a biprism for generating an interference fringe using an electron beam transmitted through a sample, and a recording device for forming and recording holograms by the biprism.

Here, as the material of the biprism, quartz fiber coated with platinum (Pt) or gold (Au) having an average diameter of 1 μm is used. The biprism is attached to a limited area aperture holder or the like.

When a voltage is applied to the biprism installed in the transmission electron microscope, a fringe is formed on the fluorescent plate by the interference between the material wave passing through the sample and the reference wave passing through the major region.

As shown in FIGS. 3 and 4, when the voltage applied to the biprism is increased, spatial resolution may be obtained by decreasing the fringe spacing S and increasing the width W. FIG. However, in order to obtain good spatial resolution and to increase the field of view (FOV), the constant voltage applied to the biprism must be increased above a certain level. On the other hand, as the deflection angle γ shown in FIG. 4 increases as the constant voltage applied to the biprism increases, the spatial coherency decreases. This decrease in the degree of spatial matching lowers the contrast of the hologram formed on the fluorescent plate.

In addition, as a conventional quartz fiber (Quartz Fiber) has a thick average diameter of 1um level, there is a problem in that the shadow effect (Shadow Effect) formed by the biprism itself appears. Therefore, the overall shadowing power (Resolving Power) of the transmission electron microscope is lowered by this shadow effect, thereby having a detection limit of the electron holography analysis.

An object of the present invention to solve this problem is to provide a sample analysis device that can reduce the shadow effect caused by the biprism of the transmission electron microscope, and can obtain an analysis result of the improved electron holography.

Sample analysis apparatus using carbon nanotube (CNT) according to the present invention for solving the above technical problem is to focus the electron beam irradiated from the electric field electron gun, the electron electron beam irradiated by the electron emission by the field emission effect of the electron sample Supplying voltage to the bi-prism and bi-prism using a condenser lens irradiated to the object, an objective lens forming an enlarged image of the sample by the electron beam transmitted through the sample, and a carbon nanotube generating an interference fringe from the electron beam transmitted through the objective lens. And a hologram recording device for forming a hologram using an interference fringe generated by the constant voltage supply unit and the biprism.

Herein, the carbon nanotubes preferably have a diameter of 1 nm to 1 μm.

Herein, the length of the carbon nanotubes is preferably 0.5 mm to 10 cm.

Here, the carbon nanotubes are preferably tubular single-walled nanotubes in which carbon atoms are connected by hexagonal rings.

Sample analysis apparatus using a nanowire according to the present invention is a field electron gun for irradiating an electron beam by the field emission effect of electrons, a condenser lens for condensing the electron beam irradiated from the field electron gun, irradiated to the sample, an electron beam transmitted through the sample Using an objective lens for forming an enlarged image of the sample by using the light source, a biprism using nanowires to generate an interference pattern from an electron beam transmitted through the objective lens, a constant voltage supply unit supplying voltage to the biprism, and an interference pattern generated from the biprism. And a hologram recording device for forming a hologram.

Herein, the nanowires preferably have a diameter of 1 nm to 1 μm.

Here, the length of the nanowires is preferably 0.5 mm to 10 cm.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention;

[Sample Analysis Device Using Carbon Nanotubes]

5 and 6 are diagrams showing a sample analysis device according to an embodiment of the present invention.

Referring to FIG. 5, a sample analyzing apparatus according to an embodiment of the present invention may include a field electron gun 301 and a field electron gun that irradiate an electron beam 304 by a field emission effect of electrons. A condenser lens for condensing the electron beam irradiated onto the sample and irradiating the sample; an objective lens 305 for forming an enlarged image of the sample by the electron beam transmitted through the sample; Biprism using carbon nanotubes (CNTs) to generate an interference fringe from an electron beam, a constant voltage supply unit 306 (Power Supply and Switch of Biprism) and a biscuit to supply voltage to the biprism. It includes a hologram recording device 308 (Media To Record The Electron Hologram) to form a hologram using the interference fringe generated in the prism.

First, the field electron gun 301 installed inside the transmission electron microscope irradiates an electron beam having high nano focusing and coherency by using a field emission effect.

Here, the field emission effect is an effect in which electrons tunnel from the surface of the conductor to the vacuum plane, and when a strong electric field is given to the conductor, the potential energy of the vacuum portion is lowered, which causes the Fermi level to be in the Fermi level. The electrons break through the energy barrier and are released into the vacuum.

Using the field emission effect, the electron beam irradiated from the field electron gun 301 is collected by the condenser lens 302 and irradiated onto the sample.

Herein, the electron beam transmitted through the condenser lens 302 refers to an object wave and a reference wave.

Subsequently, an object wave is transmitted to the sample 303 thinly manufactured to a thickness of about 1000 Hz or less, and the reference wave passes through the vacuum region.

Thereafter, the material wave and the reference wave are transmitted through the objective lens 305 to form an enlarged image of the sample. In addition, the objective lens 305 may be formed of a plurality of lenses for aberration correction.

Subsequently, the material wave and the reference wave transmitted through the objective lens 305 cause an interference phenomenon by the biprism 307 applied with the constant voltage from the constant voltage supply unit 306. This interference phenomenon forms a very delicate and complicated interference fringe on the hologram recording device.

Here, the biprism 307 is a tube-shaped carbon nanotube 307 (Carbon Nanotube: CNT) in which one carbon atom is connected to other carbon atoms by a hexagonal ring (Ref. 1) LX Zheng et al. : Ultralong Single-wall Carbon Nanotubes, Nature Materials 3, 673-676 (2004)).

In addition, the carbon nanotubes 307 are single-walled nanotubes (SWNTs) in which carbon atoms bonded by hexagonal rings are composed of one wall.

Here, the diameter of the carbon nanotubes 307 may be manufactured to about 1 nm to 1 μm.

In addition, the length of the carbon nanotubes 307 may be manufactured to about 0.5 mm to 10 cm.

The carbon nanotubes 307 may be formed to be about 500 times thinner than the materials used in the conventional biprism, at least 1 nm to 1 μm in diameter. Accordingly, the shadow effect formed by the conventional biprism itself can be minimized.

In addition, carbon nanotubes 307 connected by hexagonal rings without structural defects have a mass of about one sixth of that of steel. In addition, the mechanical strength of carbon nanotubes is about 100 times stronger than steel. In addition, the current density of the single-walled carbon nanotube (Single-Walled Carbon Nanotube) is up to 109 A / ㎡ or more and has a higher electrical conductivity than copper having a current density of 106 A / ㎡.

Accordingly, in the biprism using the carbon nanotubes 307 to which high voltage is applied, it can serve as an electrically conductive material without bending in all areas by using high current density and strong mechanical strength.

Subsequently, the electrodes of the carbon nanotubes 307 may be connected by deposition of a nanomanipulator and a focused ion beam (FIB). In addition, the carbon nanotubes 307 to which the electrodes are connected may be attached to a limited area aperture holder or the like installed in the transmission electron microscope.

As the high voltage is applied by the improved mechanical strength of the carbon nanotubes 307 thus installed, phase coherence of object waves and reference waves increases, resulting in high resolution. Resolution) and high quality interference fringes. In addition, since an interference fringe of a straight shape without warping can be obtained, a uniform hologram is formed in the entire area. As a result, resolution at the atomic level can be achieved.

Subsequently, an interference fringe obtained from an object wave and a reference wave with increased phase coherence is hologramed through a hologram recording device 308 (Media To Record the Electron Hologram). Is formed.

6 is a sample analysis apparatus using a multi-biprism.

Here, as shown in FIG. 5, a plurality of biprisms 307 using carbon nanotubes may be coupled to a plurality of biprisms 407 as shown in FIG. 6. In addition, an improved holography analysis may be performed using the multi-biprism 407 as in the sample analysis apparatus of FIG. 5.

[Sample Analysis Apparatus Using Nanowire]

5 and 6 are diagrams showing a sample analysis device according to an embodiment of the present invention.

Referring to FIG. 5, a sample analyzing apparatus according to an embodiment of the present invention may include a field electron gun 301 and a field electron gun that irradiate an electron beam 304 by a field emission effect of electrons. A condenser lens for condensing the electron beam irradiated onto the sample and irradiating the sample; an objective lens 305 for forming an enlarged image of the sample by the electron beam transmitted through the sample; Bi-prism using nanowires 307 (Nanowire) to generate an interference fringe from an electron beam, a power supply and switch of biprism, and a bi-prism It includes a hologram recording device 308 (Media To Record The Electron Hologram) for forming a hologram using the interference fringe.

First, the field electron gun 301 installed inside the transmission electron microscope irradiates an electron beam having high nano focusing and coherency by using a field emission effect.

Here, the field emission effect is an effect in which electrons tunnel from the surface of the conductor to the vacuum plane, and when a strong electric field is given to the conductor, the potential energy of the vacuum portion is lowered, which causes the Fermi level to be in the Fermi level. The electrons break through the energy barrier and are released into the vacuum.

Using the field emission effect, the electron beam irradiated from the field electron gun 301 is collected by the condenser lens 302 and irradiated onto the sample.

Herein, the electron beam transmitted through the condenser lens 302 refers to an object wave and a reference wave.

Subsequently, an object wave is transmitted to the sample 303 thinly manufactured to a thickness of about 1000 Hz or less, and the reference wave passes through the vacuum region.

Thereafter, the material wave and the reference wave are transmitted to the objective lens 305 to form an enlarged image of the sample. In addition, the objective lens 305 may be formed of a plurality of lenses for aberration correction.

Subsequently, the material wave and the reference wave transmitted through the objective lens 305 cause an interference phenomenon by the biprism 307 applied with the constant voltage from the constant voltage supply unit 306. This interference phenomenon forms a very delicate and complicated interference fringe on the hologram recording device.

Here, the nanowires 307 may be made of one of silicon (Si), tin oxide (SNO), gallium nitride (GaN), and zinc oxide (ZnO) as nanocrystals forming a nano-sized crystal phase. In addition, the nanowires may be manufactured in the form of lines, rods and wires.

Here, the diameter of the nanowires 307 may be manufactured to about 1 nm to 1 μm.

In addition, the length of the nanowires 307 may be manufactured to about 0.5 mm to 10 cm.

Such nanowires 307 may serve as thin electrically conductive wires that can minimize shadow effects using nano-level thin diameters and high field emission current densities.

The electrodes of the nanowires 307 may then be connected, typically by deposition of a nanomanipulator and a focused ion beam (FIB). In addition, the nanowire 307 to which the electrode is connected may be attached to a limited area aperture holder or the like installed in the transmission electron microscope.

The nanowire 307 installed as described above reduces the shadow effect caused by the conventional biprism itself by using a nano-level thin diameter so that the phase coherence of the object wave and the reference wave may be reduced. Phase Coherence) is increased. Accordingly, high resolution and high quality interference fringes can be obtained from the hologram of a transmission electron microscope using nanowires.

6 is a sample analysis apparatus using a multi-biprism.

Here, as shown in FIG. 5, a plurality of biprisms 307 using nanowires may be coupled to each other as illustrated in FIG. 6 and installed as a multi-biprism 407. In addition, an improved holography analysis may be performed using the multi-biprism 407 as in the sample analysis apparatus of FIG. 5.

As described above, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

As described in detail above, the sample analysis device according to the present invention can minimize the shadow effect by the biprism itself using carbon nanotubes and nanowires having a thin diameter of the nano level.

In addition, it is possible to obtain an analysis result of improved electron holography by carbon nanotubes having a stable bonding structure of carbon atoms.

Claims (7)

An electric field electron gun for irradiating an electron beam by the field emission effect of electrons; A condenser lens for condensing the electron beam irradiated from the field electron gun to irradiate the sample; An objective lens forming an enlarged image of the sample by the electron beam transmitted through the sample; Biprism using carbon nanotubes to generate an interference fringe from the electron beam transmitted through the objective lens; A constant voltage supply unit supplying a voltage to the biprism; And A hologram recording device for forming a hologram using the interference fringe generated by the biprism; Sample analysis device comprising a. The method of claim 1, The carbon nanotubes are 1 nm to 1 μm in diameter, sample analysis device. The method of claim 1, Sample length of the carbon nanotubes are 0.5 mm to 10 cm. The method of claim 1, The carbon nanotube is a sample analysis device, one carbon atom is a tubular single-walled nanotube connected to the other carbon atoms in a hexagonal ring. An electric field electron gun for irradiating an electron beam by the field emission effect of electrons; A condenser lens for condensing the electron beam irradiated from the field electron gun to irradiate the sample; An objective lens forming an enlarged image of the sample by the electron beam transmitted through the sample; Biprism using nanowires to generate an interference fringe from the electron beam transmitted through the objective lens; A constant voltage supply unit supplying a voltage to the biprism; And A hologram recording device for forming a hologram using the interference fringe generated by the biprism; Sample analysis device comprising a. The method of claim 1, The nanowires are 1 nm to 1 μm in diameter, sample analysis device. The method of claim 1, Sample analysis device, the length of the nanowire is 0.5 mm to 10 cm.
KR1020070062621A 2007-06-26 2007-06-26 Apparatus for analyzing specimen KR20080113762A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20230052355A (en) 2021-10-12 2023-04-20 에이치비솔루션㈜ Analysis system with tof-meis

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20230052355A (en) 2021-10-12 2023-04-20 에이치비솔루션㈜ Analysis system with tof-meis

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