200845084 .. 九、發明說明： • 【發明所屬之技術領域】 本發明涉及-種場發射陰極及其製備方法，尤其涉及 -種基於奈米石炭管薄膜的場發射陰極及其製備方法。 【先前技術】 奈米碳管係-種新型碳材料，其具有極其優異的導電 性能，且其具有幾乎接近理論極限的長徑比，所以，奈米 碳管係已知最好的場發射材料，其具有極低場發射電壓， 可傳輸極大電流密度，且電流極穩定，因而非常適合做場 發射顯示器的陰極發射體。 先刖技術中，使用奈米碳管作為場發射陰極的製備方 法:般包括直接生長法和印刷法。直接生長法一般採用化 相沈積法在鍍有催化義基底㈣上錢生長奈米碳 、g %發射陰極。然而，由於直魅長的奈米碳管陣列中奈 &不可避免的存在相互_且剩雜的現象，容易 導致這種場發射陰極的發射效果並不理想。 ，印刷法-般採用將含有奈米石炭管的導電聚料或者有機 枯接劑印刷成圖形通過後續處理使得奈米碳管能夠從聚料 的，藏中露出頭來成發射體。在此方法中，奈米碳管的有 效％發射體的密度較小，且將含有奈米碳管的 導電漿料以 #膜4網印_方式塗布在導電基板上，奈米碟管在聚料 务生4曲相互父織’不易形成垂直於導電基板的奈米 二s。為形成性能良好的發射尖端，需對奈米碳管進行後 、、貝處理’即將-層漿料剝離，從而使奈米碳管從漿料的埋 8 200845084 藏中露出頭來而成為發射體，惟，剝離此槳料層對太、， 管損傷很大，且生產效率低且成本較高。 ’丁、米石反 有鑒於此，提供一種製備方法步驟簡單、生 … 且成本低，易於實際_，歸有穩定的場 == 發射陰極及其製備方法實為必要。 寸性的％ 【發明内容j 一種場發射陰極，其包括— 管薄膜，其中，該奈米石山总广基底和一奈米石反 多個奈米碳管束首尾相=$膜包括擇優取向排列的 分奈米碳管從該奈米石炭管薄電基底設置，部 該奈米碳管薄臈的厚度為〇 ^ :… 該導電美底姑料皂， · 1〇〇微米。 基底材枓為氧化銦錫破璃 一種場發射陰極的势借古、+ π。 提供-導電基底；提供^少―法’其包括以下少驟. 米碳管薄膜包括擇優^層奈米碳管薄膜，該奈 尾相連，部分奈米碳管;個奈米碳管束首 及將上述奈米碳管 Ά灭管薄膜中突出；以 成場發射陰極。 、；附固定於上述導電基底形 進一步將多層奈 总# 導電基底形成場發射陰極w /#膜重4地枯附固定於 土述奈米碳管薄膜的製備 :-奈米酬列；從 夂括以下， 覓度的多個奈米碳管束；以卡反管陣列中選定一疋 于奈米石炭管陣列生長方向拉疋速度沿基本垂直 申該夕個奈米碳管束，以 200845084 “ 形成一連續的奈米碳管薄膜。 / 上述奈米碳管陣列的製備方法包括以下步驟：提 供一平整基底；在基底表面均勻形成一催化劑層；將 上述形成有催化劑層的基底在700〜900 °C的空氣中退 火約30分鐘〜90分鐘；以及將處理過的基底置於反應 爐中，在保護氣體環境下加熱到500〜74(TC，然後通 入碳源氣反應約5〜30分鐘，生長得到高度為200〜400 微米的奈米碳管陣列。 上述導電基底表面可預先形成一導電銀膠層。 可進一步使用有機溶劑處理粘附在導電基底表 面的奈米碳管薄膜。 該有機溶劑為乙醇、曱醇、丙酮、二氯乙烧或氣 仿。 相較於先前技術，所述的場發射陰極及其製備方 法，利用從一奈米碳管陣列中直接拉出的奈米碳管薄 膜，並設置於一導電基底上，方法簡單易行。所述的 奈米碳管薄膜結構中包括擇優取向排列的多個奈米 碳管束首尾相連且平行於導電基底設置，部分奈米碳 管從該奈米碳管薄膜中突出有利於發射電子，該場發 射陰極具有穩定的場發射特性。 【實施方式】 以下將結合附圖對本發明作進一步之詳細說明。 請參閱圖1，本發明實施例場發射陰極的製備方法 主要包括以下幾個步驟： 10 200845084 步驟一：提供一奈米碳管陣列，優選地，該陣列 為超順排奈米碳管陣列。 本貫施例中，超順排奈米碳管陣列的製備方法採 用化學氣相沈積法，其具體步驟包括qa)提供一平 整基底，該基底可選用p型或]^型矽基底，或選用形 成有氧化層的矽基底，本實施例優選為採用4英寸的 矽基底，（b)在基底表面均勻形成一催化劑層，該催 化f層材料可選用鐵（Fe)、銘（㈤、鎳（Nl)或其 4〜、、且。的合金之一；（c)將上述形成有催化劑層的 基底在700〜900 C的空氣中退火約30分鐘〜9〇分鐘； 將處理過的基底置於反應爐中，在保護氣體環 :兄：加t到5〇0〜74〇°C，然後通入碳源氣體反應約 分鐘，生長得到超順排奈米碳管陣列，並高卢 〜4〇〇微米。該超順排奈米碳管陣列為多個彼^平 f垂直於基底生長的奈米碳管形成的純奈米碳管 =上述控制生長條件，該超順排奈米碳管陣 1 土丨含有雜f，如無定型碳或殘留的催化劑全 屬顆粒等。該车半硭总 限丨 厌5陣列中的奈米碳管彼此通過范 k爭力緊岔接觸形成陣列。 的碳碳源氣可選用乙块等化學性質較活潑 體。σ保濩軋體可選用氮氣、氨氣或惰性氣 獲得步-=碳tr拉伸工具從奈米碳管陣列中拉取 "”人吕厚膜。该奈米碳管薄膜的製備具體包 11 200845084 括以下步驟··（a)從上述奈米碳管陣列中選定：-定寬 度的多個奈米碳管片斷，本實施例優選為採用具有一 定寬度的膠帶接觸奈米碳管陣列以選定一定寬度的 多個奈米碳管束；（b)以一定速度沿基本垂直于奈米 碳管陣列生長方向拉伸該多個奈米碳管束，以形成一 連續的奈米碳管薄膜。 在上述拉伸過程中，該多個奈米碳管束在拉力作 用下沿拉伸方向逐漸脫離基底的同時，由於范德華力 作用，該選定的多個奈米碳管束分別與其他奈米碳管 束首尾相連地連續地被拉出，從而形成一奈米竣管薄 膜。該奈米碳管薄膜為擇優取向排列的多個奈米碳管 束首尾相連形成的具有一定寬度的奈米碳管薄膜。該 奈米碳管薄膜中奈米碳管的排列方向基本平行于奈 米碳管薄膜的拉伸方向，然而，請參閱圖2，本實施 例從奈米碳管陣列直接拉出的奈米碳管薄膜中，部分 奈米碳管會從奈米碳管薄膜的表面突出。 本實施例中，該奈米碳管薄膜的寬度與奈米碳管 陣列所生長的基底的尺寸有關，該奈米碳管薄膜的長 度不限，可根據實際需求制得。本實施例中採用4英 寸的基底生長超順排奈米碳管陣列，該奈米碳管薄膜 的寬度可為lcm〜10cm，該奈米碳管薄膜的厚度為 0. 01〜100微米。 步驟三：提供一導電基底，將上述奈米碳管薄膜 粘附固定於導電基底表面，從而獲得場發射陰極。 12 200845084 本實施例中，該導電基底包括氧化銦錫（qo)玻 璃或其他可用作場發射陰極基底的導電材料。 由於本實施例步驟一中提供的超順排奈米碳管陣 列中的奈米碳管非常純淨，且由於奈米碳管本身的比 表面積非常大，所以該奈米碳管薄膜本身具有較強的 粘性。步驟三中該奈米碳管薄膜可利用其本身的粘性 直接钻附於導電基底表面。進一步地，為使得奈米碳 管薄膜牢固地附者在導電基底上’可預先在導電基底 上形成一層梳形的銀膠層，然後再鋪上奈米碳管薄膜 作為場發射陰極。由於在場發射電場較大時，奈米碳 管薄膜容易脫離導電基底，該梳形銀膠層可使奈米碳 管薄膜能更好得粘附在導電基底上。 本實施例中，該銀膠層的形狀不限於梳形，也可 形成其他形狀或一層完整的銀膠層於導電基底上。另 外，本實施例還可通過使用有機溶劑處理粘附在導電 基底表面的奈米碳管薄膜，使奈米碳管薄膜更好地固 定於導電基底。其中，該有機溶劑為揮發性有機溶 劑，如乙醇、曱醇、丙酮、二氯乙烷或氯仿，優選為 乙醇。 可以理解，本實施例還可以將多層同樣的上述奈 米碳管薄膜鋪設於同一導電基底上作為場發射陰 極，其中，奈米碳管薄膜的鋪設方向不限。 請參閱圖3，本實施例提供一場發射陰極10，其 包括一導電基底12及一奈米碳管薄膜14。該導電基 13 200845084 陰極基底錫（^™)麵或其他可用作學發射 丨友位丞坻的材料。該奈米 排列的多個奈米碳管束首尾相=包括擇優取向 12設置’部分奈米碳管 平二:導電基底 本垂直於導電基广出卡出並基 發射。該有利於電子 另外二 的厚度為〇.〇卜100微米。 重叠設；：米碳管薄膜14τ以為多層奈米碳管薄膜 士请芩閱圖4,本實施例獲得的場發射陰極在應用 時，該場發射陰極接地，並提供另一施加正電壓的基 板作為陽極，利用奈米碳管薄膜中部分突出的奈米碳 官作為場發射體，該場發射陰極具有良好地場發射性 請茶閱圖5,本發明實施例場發射陰極在應用時具 有較高的穩定性，在不同電壓下，該場發射陰極具有 %疋的場發射電流。 所述的場發射陰極及其製備方法，利用從一奈米 碳管陣列中直接拉出的奈米碳管薄膜，並設置於一導 電基底上，方法簡單易行。所述的奈米碳管薄膜結構 中包括擇優取向排列的多個奈米碳管束首尾相連且 平行於導電基底設置，部分奈米碳管從該奈米碳管薄 膜中突出有利於發射電子，該場發射陰極具有穩定的 場發射特性。 综上所述，本發明確已符合發明專利之要件，遂 14 200845084 依法提出專利申請。惟，以上所述者僅為本發明之較 ✓ _ 佳實施例，自不能以此限制本案之申請專利範圍。舉 凡熟悉本案技藝之人士援依本發明之精神所作之等 效修飾或變化，皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 圖1係本發明實施例場發射陰極的製備方法的流 程示意圖。 圖2係本發明實施例中製備的奈米碳管薄膜的掃 描電鏡照片。 圖3係本發明實施例獲得的場發射陰極的結構示 意圖。 圖4係本發明實施例場發射陰極的電流-電壓曲線 示意圖。 圖5係本發明實施例場發射陰極在不同電壓下場 發射電流示意圖。 【主要元件符號說明】 15200845084: 9. Description of the invention: • Technical field to which the invention pertains The invention relates to a field emission cathode and a preparation method thereof, in particular to a field emission cathode based on a nano-carboniferous film and a preparation method thereof. [Prior Art] Nano carbon tube system - a new type of carbon material, which has extremely excellent electrical conductivity and has an aspect ratio almost close to the theoretical limit. Therefore, the carbon nanotube system is the best known field emission material. It has a very low field emission voltage, can transmit a large current density, and is extremely stable in current, making it ideal for use as a cathode emitter for field emission displays. In the prior art, a carbon nanotube is used as a method of preparing a field emission cathode: generally includes a direct growth method and a printing method. The direct growth method generally uses a phase deposition method to deposit a nanocarbon and a g% emitting cathode on a catalytically-immobilized substrate (4). However, due to the inevitable existence of mutual _ and residual impurities in the nano-carbon nanotube array of the straight charm, it is easy to cause the emission effect of such a field emission cathode to be unsatisfactory. The printing method generally uses a conductive polymer or an organic binder containing a nano-carbon tube to be printed into a pattern, and the subsequent treatment enables the carbon nanotube to be exposed from the aggregate, and the head is formed into an emitter. In this method, the density of the effective % emitter of the carbon nanotube is small, and the conductive paste containing the carbon nanotube is coated on the conductive substrate by the film 4, and the nano tube is gathered. It is not easy to form a nanosecond s perpendicular to the conductive substrate. In order to form a good performance of the launch tip, the carbon nanotubes need to be post-processed, and the shell-like treatment is to be stripped, so that the carbon nanotubes are exposed from the slurry of the buried layer 200848084 and become the emitter. However, the stripping of the paddle layer is too large, the tube damage is large, and the production efficiency is low and the cost is high. In view of this, it is necessary to provide a preparation method with simple steps, low cost, low cost, easy to be practical, and stable field == emission cathode and its preparation method. % of the inventivity [Inventive content j] A field emission cathode comprising a tube film, wherein the nanometer stone base and the nanometer stone and the plurality of carbon nanotube bundles have a head-to-tail phase = $ film including a preferred orientation The carbon nanotubes are arranged from the thin electric base of the carbonaceous carbon tube, and the thickness of the carbon nanotubes of the carbon nanotubes is 〇^:... The conductive espresso soap, 1 〇〇 micron. The base material 枓 is indium tin oxide. The potential of a field emission cathode is ancient, + π. Providing - a conductive substrate; providing a "less" method comprising the following minor steps. The carbon nanotube film comprises a preferred layer of carbon nanotube film, the tail is connected, a portion of the carbon nanotube; a carbon nanotube bundle head and the above The carbon nanotube tube is protruded in the film; the cathode is emitted in a field. Attached to the above-mentioned conductive base shape to further form a multilayer nanometer conductive substrate to form a field emission cathode w / # membrane weight 4 dry attachment to the preparation of the carbon nanotube film: - nano reward; from 夂Included in the following, a plurality of carbon nanotube bundles with a twist; a selected one of the carbon nanotube arrays in the card-backed tube array is pulled along the growth direction of the nano-carbon nanotube bundle, and a continuous vertical carbon nanotube bundle is formed at 200845084 to form a continuous The carbon nanotube film is prepared by the following steps: providing a flat substrate; forming a catalyst layer uniformly on the surface of the substrate; and forming the substrate with the catalyst layer formed at 700 to 900 ° C Annealing in air for about 30 minutes to 90 minutes; and placing the treated substrate in a reaction furnace, heating to 500 to 74 (TC in a protective gas atmosphere, and then reacting with a carbon source gas for about 5 to 30 minutes to grow A carbon nanotube array having a height of 200 to 400 micrometers. A surface of the conductive substrate may be preliminarily formed with a conductive silver paste layer. The carbon nanotubes adhered to the surface of the conductive substrate may be further treated with an organic solvent. The organic solvent is ethanol, decyl alcohol, acetone, dichloroethane or gas. Compared with the prior art, the field emission cathode and the preparation method thereof are directly pulled out from an array of carbon nanotubes. The carbon nanotube film is disposed on a conductive substrate, and the method is simple and easy. The carbon nanotube film structure includes a plurality of carbon nanotube bundles arranged in a preferential orientation, which are connected end to end and arranged parallel to the conductive substrate. The carbon nanotubes protrude from the carbon nanotube film to facilitate electron emission, and the field emission cathode has stable field emission characteristics. [Embodiment] Hereinafter, the present invention will be further described in detail with reference to the accompanying drawings. The preparation method of the field emission cathode of the embodiment of the invention mainly comprises the following steps: 10 200845084 Step 1: providing a carbon nanotube array, preferably, the array is a super-sequential carbon nanotube array. The method for preparing a super-sequential carbon nanotube array adopts a chemical vapor deposition method, and the specific steps thereof include qa) providing a flat substrate, and the substrate may be selected from p-type or ^-type sulfhydryl groups. The bottom layer, or the tantalum substrate formed with the oxide layer, is preferably a 4-inch tantalum substrate, (b) a catalyst layer is uniformly formed on the surface of the substrate, and the catalytic fr layer material may be iron (Fe) or (5) one of nickel (Nl) or its alloy of 4 to, (c) annealing the substrate on which the catalyst layer is formed in air of 700 to 900 C for about 30 minutes to 9 minutes; The substrate is placed in the reaction furnace, in the protective gas ring: brother: add t to 5 〇 0~74 〇 ° C, and then pass through the carbon source gas reaction for about a minute, grow to obtain a super-sequential carbon nanotube array, and high Lu ~ 4 〇〇 micron. The super-sequential carbon nanotube array is a plurality of pure carbon nanotubes formed by a carbon nanotube perpendicular to the substrate growth = the above controlled growth conditions, the super-shun The carbon nanotube array 1 soil contains impurities such as amorphous carbon or residual catalysts. The carbon nanotubes in the array of the vehicle are generally in contact with each other to form an array by close contact with each other. The carbon-carbon source gas can be selected from chemically active substances such as B. The σ Baoding rolling body can be obtained by using nitrogen, ammonia or inert gas to obtain a step-=carbon tr stretching tool to pull the “human Lu thick film” from the carbon nanotube array. The preparation of the carbon nanotube film is specifically packaged. 11 200845084 includes the following steps: (a) selecting from the above-mentioned carbon nanotube array: a plurality of carbon nanotube segments of a fixed width, in this embodiment, preferably using a tape having a certain width to contact the carbon nanotube array Selecting a plurality of carbon nanotube bundles of a certain width; (b) stretching the plurality of carbon nanotube bundles at a constant speed in a direction substantially perpendicular to the growth direction of the carbon nanotube array to form a continuous carbon nanotube film. In the above stretching process, the plurality of carbon nanotube bundles are gradually separated from the substrate in the stretching direction under the tensile force, and the selected plurality of carbon nanotube bundles are respectively connected end to end with the other carbon nanotube bundles due to van der Waals force. The ground is continuously pulled out to form a nano-tube film, which is a carbon nanotube film having a certain width formed by connecting a plurality of carbon nanotube bundles arranged in a preferential orientation. Carbon tube film The arrangement direction of the carbon nanotubes is substantially parallel to the stretching direction of the carbon nanotube film. However, referring to FIG. 2, in the carbon nanotube film directly pulled out from the carbon nanotube array in this embodiment, a part of the nanometer tube The carbon tube protrudes from the surface of the carbon nanotube film. In this embodiment, the width of the carbon nanotube film is related to the size of the substrate on which the carbon nanotube array is grown, and the length of the carbon nanotube film is not limited. It can be prepared according to actual needs. In this embodiment, a 4-inch substrate is used to grow a super-sequential carbon nanotube array, and the width of the carbon nanotube film can be from 1 cm to 10 cm, and the thickness of the carbon nanotube film is 0. 01~100 microns. Step 3: Providing a conductive substrate, the above-mentioned carbon nanotube film is adhered and fixed on the surface of the conductive substrate to obtain a field emission cathode. 12 200845084 In this embodiment, the conductive substrate comprises indium tin oxide. (qo) glass or other electrically conductive material that can be used as a field emission cathode substrate. The carbon nanotubes in the super-sequential carbon nanotube array provided in step one of the present embodiment are very pure and due to the carbon nanotube itself. Specific surface The carbon nanotube film itself has a strong viscosity. In step 3, the carbon nanotube film can be directly attached to the surface of the conductive substrate by its own viscosity. Further, to make the carbon nanotube The film is firmly attached to the conductive substrate. A comb-shaped silver paste layer can be formed on the conductive substrate in advance, and then a carbon nanotube film is deposited as a field emission cathode. Since the field emission electric field is large, the nanometer is large. The carbon tube film is easily separated from the conductive substrate, and the comb-shaped silver layer can better adhere the carbon nanotube film to the conductive substrate. In this embodiment, the shape of the silver layer is not limited to a comb shape, and Forming other shapes or a complete layer of silver glue on the conductive substrate. In addition, the embodiment can also better fix the carbon nanotube film by treating the carbon nanotube film adhered on the surface of the conductive substrate with an organic solvent. On a conductive substrate. Among them, the organic solvent is a volatile organic solvent such as ethanol, decyl alcohol, acetone, dichloroethane or chloroform, preferably ethanol. It can be understood that, in this embodiment, a plurality of layers of the above-mentioned carbon nanotube film can be laid on the same conductive substrate as a field emission cathode, wherein the laying direction of the carbon nanotube film is not limited. Referring to FIG. 3, this embodiment provides a field emission cathode 10 including a conductive substrate 12 and a carbon nanotube film 14. The conductive group 13 200845084 cathode base tin (^TM) surface or other material that can be used as a learning emitter. The nano-carbon nanotube bundles in the nano-column arrangement include the preferred orientation 12 setting 'partial carbon nanotubes flat two: the conductive substrate is perpendicular to the conductive base and is out of the base and emits. This is advantageous for electrons. The thickness of the other two is 100.〇100 microns. Overlap setting: the carbon nanotube film 14τ is a multilayer carbon nanotube film. Please refer to FIG. 4. The field emission cathode obtained in this embodiment is grounded when applied, and another substrate applying a positive voltage is provided. As the anode, a partially protruding nano carbon official in the carbon nanotube film is used as a field emitter, and the field emission cathode has good field emission. Please refer to FIG. 5, and the field emission cathode of the embodiment of the invention has a higher application time. The stability of the field emission cathode has a field emission current of % 在 at different voltages. The field emission cathode and the preparation method thereof are simple and easy to use by using a carbon nanotube film directly pulled out from an array of carbon nanotubes and disposed on a conductive substrate. The carbon nanotube film structure includes a plurality of carbon nanotube bundles arranged in a preferential orientation, which are connected end to end and arranged parallel to the conductive substrate, and a portion of the carbon nanotubes protrude from the carbon nanotube film to facilitate electron emission. The field emission cathode has stable field emission characteristics. In summary, the present invention has indeed met the requirements of the invention patent, and 遂 14 200845084 filed a patent application according to law. However, the above is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application in this case. Equivalent modifications or variations made by those skilled in the art to the spirit of the invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic flow chart showing a method of preparing a field emission cathode according to an embodiment of the present invention. Fig. 2 is a scanning electron micrograph of a carbon nanotube film prepared in an example of the present invention. Fig. 3 is a schematic view showing the structure of a field emission cathode obtained in an embodiment of the present invention. Fig. 4 is a schematic view showing a current-voltage curve of a field emission cathode according to an embodiment of the present invention. Fig. 5 is a schematic view showing the field emission current of a field emission cathode at different voltages according to an embodiment of the present invention. [Main component symbol description] 15