WO2019156337A1 - Matériau émetteur d'électrons amorphe stable dans l'air et procédé de fabrication associé - Google Patents

Matériau émetteur d'électrons amorphe stable dans l'air et procédé de fabrication associé Download PDF

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Publication number
WO2019156337A1
WO2019156337A1 PCT/KR2018/016083 KR2018016083W WO2019156337A1 WO 2019156337 A1 WO2019156337 A1 WO 2019156337A1 KR 2018016083 W KR2018016083 W KR 2018016083W WO 2019156337 A1 WO2019156337 A1 WO 2019156337A1
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WIPO (PCT)
Prior art keywords
emitting material
electron
amorphous
electron emitting
present
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PCT/KR2018/016083
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English (en)
Korean (ko)
Inventor
김성웅
이규형
강세황
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성균관대학교산학협력단
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Publication of WO2019156337A1 publication Critical patent/WO2019156337A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/30—Cold cathodes, e.g. field-emissive cathode
    • H01J1/304—Field-emissive cathodes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G27/00—Compounds of hafnium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/02—Amorphous compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
    • C01P2002/85—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by XPS, EDX or EDAX data
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
    • C01P2004/84—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases one phase coated with the other
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/304—Field emission cathodes
    • H01J2201/30446—Field emission cathodes characterised by the emitter material
    • H01J2201/30449—Metals and metal alloys

Definitions

  • the present invention relates to an electron emitting material and a method of manufacturing the same. More particularly, the present invention relates to an amorphous electron-emitting material that is stable in air, and to a method of manufacturing the same, which can increase the emission current at a low driving voltage due to its low work function.
  • Field emission display is a device that emits phosphors and displays images by emitting phosphors, which is one of the core technologies of large area display.
  • the fluorescent tube or lighting device uses a micro electron source with an electron emitter that emits electrons by a strong current. If the diameter of the tube is reduced by using a material having excellent electron emission characteristics, the tube is not only high luminance but also compact in size. It is possible to apply to the backlight of the non-light-emitting display device, such as liquid crystal.
  • the prior art used for FEDs or fluorescent tubes utilizes the principle that an electron beam is emitted from the electron emitter and the phosphor is excited to emit light by applying a high voltage between the electron emitter and the electrode material.
  • a metal or carbon-based material such as Mo is mainly used.
  • Metal or carbon-based materials such as Mo, which are currently used, have a work function directly related to the ease of electron emission at a level of 4 eV, and thus a method of inducing concentration by forming a fine needle structure for electron emission at low voltage is used.
  • the inventors of the present invention have developed amorphous Hf 2 S 1-y having a work function of at least 20% lower than that of Mo and carbon-based materials while studying electron emission materials having low work function properties.
  • Such amorphous Hf 2 S 1 -y is formed on the surface of the crystalline material to a thickness of several tens of nm. Also crystalline Hf 2 S 1 -y is a surface oxide easily create a HfO 2 layer to lower the work function, but the conductive properties are degraded, such as shrinking, amorphous Hf 2 S 1 -y is maintained on the surface structure compared to crystalline material is It is easy to minimize the deterioration of characteristics.
  • An object of the present invention is to provide an electron-emitting material containing the amorphous Hf 2 S 1 -y and a manufacturing method thereof.
  • the present invention provides an amorphous electron emitting material having a composition including Hf and S and represented by the following Chemical Formula 1.
  • the material surface of the formula (1) composition is Hf and S is distributed in a composition ratio of approximately 2: 1, but the amount of S may be locally excessive or insufficient.
  • the present invention also provides an electron emitter, characterized in that it comprises the amorphous electron-emitting material powder exposed to the surface.
  • this invention provides the fluorescent tube provided with the said electron emitter.
  • the present invention comprises a first step of producing a compound raw material by a heat treatment process; Melting and cooling the obtained raw material of the first system to prepare a homogeneous electron-emitting material; And it provides a method for producing an amorphous electron-emitting material powder comprising a third step of crushing and grinding the surface of the material obtained in the third step.
  • it provides a method for producing an amorphous electron-emitting material comprising a third step of crushing and grinding the surface of the material prepared in the second step.
  • the melting is preferably carried out in an inert gas atmosphere.
  • the second step may be performed once or twice or more times.
  • scraping the surface of the material prepared in the second step may be performed through chemical etching or mechanical polishing.
  • the shaving of the surface of the material prepared in the second step is preferably performed in an inert gas atmosphere for preventing oxidation such as vacuum, argon or nitrogen atmosphere.
  • the grinding can be done using ball milling, attrition milling, high energy milling, jet milling or grinding using a mortar and pestle.
  • the grinding can be done by gas atomization.
  • the S powder may be added at a ratio of 0.8 to 1.2 with respect to 2 moles of the Hf powder.
  • the third step of grinding may be performed in a vacuum or inert gas atmosphere.
  • the electron-emitting material of the present invention exhibits a very large electron-emitting effect due to the low work function characteristics expressed from the presence of localized electron layers of amorphous Hf 2 S 1 -y material.
  • Hf 2 S 1 -y included in the electron-emitting material of the present invention does not depend heavily on the value of y and has a value of about 3.0 eV. This is more than 30% lower than the work function of about 4.3 eV level of commercial electron emission material Mo and carbon. When applied to FED and fluorescent tube, it is possible to obtain a large emission current at low driving voltage without changing the existing device structure. .
  • the method for preparing Hf 2 S 1 -y electron-emitting materials provided in the present invention can easily produce a large amount of materials by simple heat treatment, melt-solidification and mechanical grinding processes.
  • the electron-emitting material provided in the present invention is easy to manufacture and can emit electrons at a low driving voltage. Therefore, it is possible to implement an electron emitter that forms a relatively large emission current based on the same applied voltage reference can be effectively applied to low-voltage driving FED, fluorescent tube and lighting device.
  • the electron-emitting material of the present invention is a TEM photograph of a microstructure y (0.2 ⁇ y ⁇ 0.2) .
  • Amorphous Hf 2 S 1 -y material is formed on the crystalline Hf 2 S surface to a thickness of several tens of nm. Localized electrons exist between the amorphous layer atoms, which is the source of the low work function properties.
  • FIG. 2 is an X-ray photoelectron spectroscopy (XPS) analysis result of amorphous Hf 2 S 1 -y prepared in Example 1.
  • XPS X-ray photoelectron spectroscopy
  • Example 3 is a core level X-ray photoelectron spectroscopy analysis of the amorphous Hf 2 S 1 - y prepared in Example 1. The area of each graph can be obtained to determine the composition of the substance Hf 2 S 1-y .
  • FIG. 4 shows the results of ultraviolet photoelectron spectroscopy (UPS) analysis on amorphous Hf 2 S 1 -y prepared in Example 1.
  • UPS ultraviolet photoelectron spectroscopy
  • FIG. 5 is an analysis result of re-measurement after 30 days of the XPS / UPS result and the measured raw material measured in FIG. 2.
  • FIG. 6 is a graph comparing the conductivity of crystalline and amorphous Hf 2 S 1 -y raw materials before and after oxidation. As a result, the conductivity deterioration of the crystalline raw material is severe, but the conductivity deterioration of the amorphous raw material is small.
  • FIG. 7 is a diagram showing the results of measurement of an electronized sample in a state before polishing and removing the surface oxidized in Example 1 by X-ray photoelectron spectroscopy. It can be seen that the pick due to oxidation is clearly visible on the surface.
  • an amorphous electron-emitting material of a composition comprising Hf and S and represented by the following formula (1).
  • the electron-emitting material represented by Formula 1 may have a large or small composition of S locally due to the nature of the amorphous material, but the overall composition converges on the Hf 2 S composition, and the electron-emitting property is not sensitive to the amount of S.
  • the electron-emitting material exhibits a large electron-emitting effect by its low work function, including localized high-density electrons.
  • the electron-emitting material may be an amorphous layer existing in the range of several to several tens of nm on the powder or bulk surface.
  • step (a) preparing a compound raw material by a heat treatment process; And (b) melting and cooling the raw material obtained in step (a) to produce a homogeneous electron emitting material. And (c) there is provided a method for producing an amorphous electron-emitting material powder comprising the step of grinding the material obtained in step (b).
  • Step (a) is a step of heat-treating a mixture of raw materials for seed phase synthesis prior to the melting process to produce the electron-emitting material.
  • Hf and S raw materials vacuum-sealed in a silica tube is put into a furnace and heat-treated for 2 to 4 days at 450 to 600 °C.
  • Step (b) is to increase the purity and homogeneity of the electron-emitting material.
  • the heat-treated mixture prepared in step (a) is placed in an arc melting facility chamber to form an inert gas atmosphere such as argon at a level capable of arc driving after forming a vacuum atmosphere. Thereafter, an arc is applied to melt the heat-treated mixture to solidify to produce an electron-emitting material.
  • an inert gas atmosphere such as argon
  • the melting method may be carried out by a commonly used melting method, for example, a process selected from the group consisting of a high temperature tubular furnace, an ultra high temperature electric furnace, and the like, and may be preferably performed by arc melting.
  • a commonly used melting method for example, a process selected from the group consisting of a high temperature tubular furnace, an ultra high temperature electric furnace, and the like, and may be preferably performed by arc melting.
  • the present invention is not necessarily limited to these methods, and any method that can be used as a melting method in the art is possible.
  • the arc melting method industrial mass production of electron-emitting materials is possible, and improved physical properties can be obtained even when a general melting method other than the arc melting method is used.
  • the raw material in order to prevent oxidation of a mixed raw material, the raw material is melted in a process of making a liquid state by heating the raw material above a melting point in an inert gas atmosphere. It is possible to obtain an electron-emitting material having a size and a shape corresponding to a sample charging part made of a copper material in an arc melting facility chamber. In order to increase the purity and homogeneity of electron-emitting materials, melting by arc melting may be repeated.
  • Step (c) is a step of preparing a powder.
  • the powder is prepared by using a mechanical grinding process such as ball milling to remove the oxidized portion during the process by scraping off the surface of the material in the form of agglomerates prepared in step (b) and preventing oxidation.
  • a mechanical grinding process such as ball milling to remove the oxidized portion during the process by scraping off the surface of the material in the form of agglomerates prepared in step (b) and preventing oxidation.
  • a method of removing the oxidized portion of the surface of the material may be a method such as chemical etching, mechanical polishing that can remove the hafnium oxide in an inert gas atmosphere.
  • etching using a mixture of hydrofluoric acid or hydrofluoric acid and various ether organic solvents in a glove box, or polishing using abrasive stone, abrasive paper, grounder, polisher or the like can be used.
  • the melt-solidified material is pulverized by a method such as ball milling, attrition milling, high energy milling, jet milling, mortar, etc. It can be prepared in the form of a powder, but is not necessarily limited to these, any method that can be used in the art as a method for producing a powder by grinding the raw material in a dry or wet manner.
  • step (c) is preferably performed in an inert gas atmosphere such as vacuum, argon or nitrogen to prevent oxidation of the material.
  • the electron-emitting material powder may be prepared by gas atomization (gas atomization).
  • gas atomization gas atomization
  • the compound raw material prepared by the melting method is heated to a melting point or more to form a liquid state, and rapidly sputtered by rapid ejection into a space of vacuum or argon atmosphere at room temperature through a nozzle to obtain a spherical raw material powder.
  • Hf 2 S 1 -y is a phase that appears at high temperature, whereas S has a very low vaporization point, so pure S is converted into Hf-S through the sintering process in order to minimize the loss of S when melting the material for synthesis.
  • the intermediate materials made by sintering are synthesized by melting and solidifying by arc melting method, and then oxidized surface in the glove box is removed by grinding and then crushed by ball milling.
  • the prepared raw material naturally forms an amorphous material of Hf 2 S 1 -y composition (0.2 ⁇ y ⁇ 0.2) on the crystalline Hf 2 S surface as shown in the TEM photograph shown in FIG. 1.
  • the oxidation of the prepared raw materials and the valence state of the elements were measured using XPS as shown in FIG. 2.
  • the raw material was crushed inside the XPS equipment. As shown in the data, the material was not oxidized, thus confirming that there was no material degradation due to oxidation.
  • the y value of amorphous Hf 2 S 1 -y was determined by core level XPS measurement.
  • the area of the Hf and S core level graphs can be obtained and substituted into the following equation to obtain the composition.
  • n i I i S i is the composition ratio, graph area, and previously reported sensitivity factor for element i , respectively.
  • the work function was measured in the same manner as in Example 1 for Mo and C.
  • Table 1 shows the work function measurement results of amorphous Hf 2 S 1 -y , Mo, and C prepared in Example 1 and Comparative Example 1.
  • Example 1 In order to evaluate the stability of Hf 2 S 1 -y , the amorphous Hf 2 S 1 -y powder prepared in Example 1 was measured again after about 30 days. As shown in the XPS and UPS results of FIG. 5, no significant difference was found in the data before / after 30 days and there was no degradation of the work function value.
  • Crystalline Hf 2 S-based materials are easily oxidized to form HfO 2 layers having a high work function and low conductivity. Therefore, when manufacturing an electron emission device using crystalline Hf 2 S, sufficient conductivity may not be obtained, deterioration of characteristics may occur, and thus desired characteristics may not be obtained or reliability of the device may be degraded.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Cold Cathode And The Manufacture (AREA)

Abstract

La présente invention concerne un matériau émetteur d'électrons et un procédé de fabrication associé. Plus particulièrement, la présente invention concerne un matériau émetteur d'électrons amorphe qui est stable dans l'air et qui permet un fort courant d'émission à une faible tension d'attaque grâce à son faible travail d'extraction, et un procédé de fabrication associé. Le matériau émetteur d'électrons de la présente invention présente une caractéristique de travail d'extraction inférieure de 30 % ou plus au travail d'extraction des matériaux émetteurs d'électrons commerciaux Mo et carbone, qui sont à un niveau d'environ 4,3 eV. Ainsi, l'application du matériau émetteur d'électrons à un FED et à des tubes fluorescents permet un fort courant d'émission à une faible tension d'attaque sans modification structurale de dispositifs préexistants. De plus, le matériau émetteur d'électrons de la présente invention peut être fabriqué à grande échelle au moyen d'un traitement thermique simple, d'une fusion-solidification et de processus de polissage mécanique.
PCT/KR2018/016083 2017-11-15 2018-12-18 Matériau émetteur d'électrons amorphe stable dans l'air et procédé de fabrication associé WO2019156337A1 (fr)

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KR20170152643 2017-11-15
KR1020180016486A KR101965813B1 (ko) 2017-11-15 2018-02-09 공기 중에서 안정한 비정질 전자방출 물질 및 이의 제조방법
KR10-2018-0016486 2018-02-09

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004307869A (ja) * 2004-05-19 2004-11-04 Sony Corp 蛍光体粉末及びその製造方法、表示用パネル、並びに、平面型表示装置
KR20110011586A (ko) * 2009-07-28 2011-02-08 성균관대학교산학협력단 산질화물계 형광체 분말, 질화물계 형광체 분말, 및 이들의 제조 방법
KR20110016289A (ko) * 2009-08-11 2011-02-17 고양미 탄소나노판 복합체 제조방법
KR20110081685A (ko) * 2010-01-08 2011-07-14 한국과학기술연구원 상온에서 증착된 Ｍｇ２Ｈｆ５Ｏ１２를 포함하는 유전체 박막, 이를 포함하는 캐퍼시터 및 트랜지스터와 이들의 제조방법
KR20170055082A (ko) * 2015-11-10 2017-05-19 성균관대학교산학협력단 전자방출 물질 및 이의 제조방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004307869A (ja) * 2004-05-19 2004-11-04 Sony Corp 蛍光体粉末及びその製造方法、表示用パネル、並びに、平面型表示装置
KR20110011586A (ko) * 2009-07-28 2011-02-08 성균관대학교산학협력단 산질화물계 형광체 분말, 질화물계 형광체 분말, 및 이들의 제조 방법
KR20110016289A (ko) * 2009-08-11 2011-02-17 고양미 탄소나노판 복합체 제조방법
KR20110081685A (ko) * 2010-01-08 2011-07-14 한국과학기술연구원 상온에서 증착된 Ｍｇ２Ｈｆ５Ｏ１２를 포함하는 유전체 박막, 이를 포함하는 캐퍼시터 및 트랜지스터와 이들의 제조방법
KR20170055082A (ko) * 2015-11-10 2017-05-19 성균관대학교산학협력단 전자방출 물질 및 이의 제조방법

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