200945401 九、發明說明： 【發明所屬之技術領域】 本發明涉及一種熱發射電子源，尤其涉及一種基於奈 米碳管的熱發射電子源。 【先前技術】 熱電子發射係把物體加熱到足夠高的溫度，物體内部 電子的此量隨著溫度的升高而增大，其中一部分電子的能 ❾量大到足以克服阻礙它們逸出的障礙，即逸出功，而由物 體内進入真空。在熱電子發射過程中，發射電子的物體被 稱為熱發射電子源。良好的熱發射電子源的材料應滿足下 列要求：其一，逸出功低，熔點高，蒸發率小；其二，具 Ϊ良好的機械性能，尤其高溫性能；其三，良好的化學穩 疋性。普通熱電子源材料通常採用純金屬材料、爛化物材 料或者氧化物材料。 採用純金屬材料製備熱發射電子源時，通常熱發射電 子源為帶狀、絲狀、薄膜狀或網狀的純 較高的比表面積。傳统的亦盔屏私曰t 一有 很得統的亦為最常見的熱發射電子源為純 2絲，其由許多纖維狀的長條微晶組成。純鶴絲作為哉發 射電子源的優點係價格較便宜，對真空度要求不高，缺點 係熱電子發射效率低，發射源直徑較大，即使經過二級或 ^級聚光鏡’在樣品表面上的電子束斑直徑也在5奈米·7 “，因此儀器解析度受到限制。而且，鶴絲被加熱到高 ^冷卻後即產生再結晶，其晶粒由原㈣細長_變為 塊狀結晶，因此，鶴絲易變脆，極易斷裂，大 作為熱發射電子源的壽命。 … 200945401 採用硼化物材料或金屬氧化物材料製備熱發射電子 * 源時，該熱發射電子源的結構為硼化物材料或金屬氧化物 - 材料包覆在耐熔基金屬基底的表面。由於此類熱發射電子 源的化學性能十分穩定，且逸出功較低，所以廣泛地用作 電子束分析儀器、電子束加工設備、粒子加速器以及其他 一些動態真空系統中的電子源。然而這樣製備的熱發射電 子源中塗層和金屬基底結合不牢固，容易脫落。此外，在 工作溫度下，熱發射電子源中的硼元素容易蒸發，極大縮 ❹短了熱電子發射體的壽命。 奈米碳管（Carbon Nanotube，CNT)係一種新型碳材 料，請參見“Helical Microtubules of Graphitic Carbon”，S. Iijima，Nature，vol.354, p56 (1991)。奈米碳管具有極優異 的導電性能、良好的化學穩定性和大的長徑比，且具有較 高的機械強度，因而奈米碳管在熱發射真空電子源領域具 有潛在的應用前景。柳鵬等人提供一種基於奈米碳管的熱 發射電子源，請參見"Thermionic emission and work Ο function of multiwalled carbon nanotube yarns", Peng Liu et al，PHYSICAL REVIEW B，Vol73, P235412-l(2006)。該熱 發射電子源採用奈米碳管長線作為熱發射電子源，由於奈 米碳管具有較高的機械強度，因此該熱發射電子源具有較 長的壽命，然，由於奈米碳管具有較高的逸出功（4.54-4.64 電子伏），所以該熱發射電子源發射效率較低，當奈米碳 管長線的溫度達到2000°C時方能發射電子，因此，難以在 較低的溫度下獲得較高的熱發射電流密度。 有鑑於此，提供一種壽命較長，能在較低的溫度下發 200945401 射電子且發射效率較高的熱發射電子源實為必要。 【發明内容】 一種熱發射電子源包括一奈米碳管絞線，其中，該奈 米碳管絞線包括複數個相互纏繞的奈米碳管，該熱發射 電子源進一步包括低逸出功材料顆粒’該低逸出功材料 顆粒至少部分填充於該奈米碳管絞線内。 與先前技術相比較，本技術方案所提供的熱發射電子 源中低逸出功材料填充於奈米碳管絞線内，與奈米碳管 絞線結合牢固，不易脫落，因此該熱發射電子源壽命較 長。而且，低逸出功材料可以使該熱發射電子源能在較 ，的溫度下發射電子，因此該熱發射電子源發射效率較 =。另外，該熱發射電子源可廣泛應用於真空螢光顯示 器、X射線管和電子腔等儀器設備中。 【實施方式】 以下將結合附圖詳細說明本技術 Ο 其製備方法 i，本技術方案實_提供—種射 :1〇 ,包括至少一奈米碳管絞線12，該熱發射二 進一步包括複數個低逸出功材料釤 逸出功；P 該低 面。 ：勻分佈於奈米碳管絞線12内部或表 崎地，±㈣魏電子源i 冤極16和一第-雷始 少匕栝一第一 第-電極18’第一電極16和一第二電極18 200945401 間iW置於熱發射電子源1G的兩端’並與熱發射電子源 10的兩端電性連接，可通過導電膠將熱發射電子源1〇的 兩端刀別枯附於第一電極16和一第二電極18上。所述電 極材料可選擇為金、銀、銅、奈米碳管或石墨等導電物質， 所述第一電極16和第二電極18的具體結構不限，本實施 例中，所述第-電極16和第二電極18優選為—長方體結 構的銅塊，熱發射電子源10的兩端分別通過銀膠粘附於第 ❹一電極16和第二電極18上，實現熱發射電子源1〇與第一 電極16和第二電極18的電性連接。第一電極“和第二電 極U用於使熱發射電子源1〇與外部電路電連接，使熱發 射電子源10在應用時更加方便。 ★所述之奈米碳管絞線12包括複數個相互纏繞的奈米 碳管，奈米碳管在奈米碳管絞線12中均勻分佈，該夺米 碳管之間通過凡德瓦爾力緊密結合。該奈米碳管絞線、 徑為20微米-1毫米。該奈米碳管絞線12中的奈米 ◎碳管為單壁奈米碳管、雙壁奈米碳管、多壁奈求碳^或 其任意組合的混合物。所述單壁奈米碳管的直徑為〇 5 奈来，雙壁奈米礙管的直徑為㈣奈米，多壁奈采碳管 的直徑為1.5-50奈米，奈米碳管的長度均為1〇微米％⑼ 微米。 所述低逸出功材料顆粒14為氧化鋇顆粒、氧化锶顆 粒、氧化鈣顆粒、硼化钍顆粒、硼化釔顆粒或其任意組合 的混合物，該低逸出功材料顆粒14的直徑為1〇卉 〇〇 微米。 不 請參閱圖2 ’所述低逸出功材料顆粒14至少部分填充 9 200945401 ==線12内部。低逸出功材料顆 ::，管絞線12的質量的5。可以理解， .與奈米碳管絞線12的結構關係包括以下三= =況:其。當逸出功材料顆粒14的直徑小於 填充:奈米碳二直二内=_= ^ ::-部分填充於奈米碳管絞線 β顆粒14另一部分在奈米碳管絞線12的表面；其二一此 =出功㈣齡14也可完全分佈在奈米碳管二“ =於低逸出功材料顆粒14至少部分填充於奈米碳； 線逸出功材料顆粒14與奈米碳管絞 合較為㈣。熱發射電子源Η)發射電子時的溫产 二^材料顆粒14的質量有關。低逸出功材料顆粒 低逸出力熱發射電子源1〇發射電子時的溫度越低， ===質量越小，熱發射電子源發射 ❹的最低發射溫度可為80(^方案所^供的熱發射電子源10 進一步地，兩個或兩個以上的至少内 功材料顆粒14的奈米好絞線12可相互扭曲纏 熱發射電子源10’該熱發射電子源1G具有更大的直徑， 方便應用於宏觀領域，且該熱發射電子源1〇強 喜 命較長。 ％ 進-步地’至少-至少内部填充有低逸出功材料顆粒 14的奈米碳管轉12可與至少—導線（圖未㈡相互扭 曲纏抓形成-複合纟5C線結構，該複合絞線結構作為熱發射 200945401 電子源ίο可具有較大的強度，壽命較長。該導線的材料不 限，可為金、銀、銅、或石墨等導電物質。200945401 IX. INSTRUCTIONS: [Technical Field] The present invention relates to a heat-emitting electron source, and more particularly to a heat-emitting electron source based on a carbon nanotube. [Prior Art] A thermal electron emission system heats an object to a temperature high enough that the amount of electrons inside the object increases as the temperature increases, and the energy of a part of the electrons is large enough to overcome the obstacles that hinder their escape. That is, the work is released, and the vacuum is entered from the inside of the object. In the process of thermal electron emission, an object that emits electrons is called a source of thermal emission electrons. The material of a good thermal emission electron source should meet the following requirements: first, low work function, high melting point, low evaporation rate; second, good mechanical properties, especially high temperature performance; third, good chemical stability Sex. Ordinary hot electron source materials are usually made of pure metal materials, erosive materials or oxide materials. When a heat-emitting electron source is prepared from a pure metal material, the heat-emitting electron source is usually a purely high specific surface area of a ribbon, a filament, a film or a mesh. The traditional one is also very well-known. The most common source of thermal emission electrons is pure 2 filament, which consists of many fibrous long strips of crystallites. The advantages of pure crane wire as the electron source of strontium are cheaper, the vacuum is not high, the disadvantage is that the thermal electron emission efficiency is low, and the diameter of the emission source is large, even after passing through the secondary or ^ concentrating mirror on the surface of the sample. The diameter of the electron beam spot is also 5 nm·7", so the resolution of the instrument is limited. Moreover, the crane wire is heated to a high temperature to recrystallize, and the crystal grains are changed from the original (four) slender to the bulk crystal. Therefore, the crane wire is brittle, extremely easy to break, and has a long life as a source of thermal emission electrons. 200945401 When a thermally-emitting electron* source is prepared using a boride material or a metal oxide material, the structure of the heat-emitting electron source is boride. Material or metal oxide - material coated on the surface of the refractory-based metal substrate. Because of its stable chemical properties and low work function, such thermal emission electron sources are widely used as electron beam analysis instruments and electron beams. Processing equipment, particle accelerators, and other sources of electrons in dynamic vacuum systems. However, the thermal emission electron source thus prepared is not well bonded to the metal substrate and is easy to bond. In addition, at the working temperature, the boron element in the heat-emitting electron source is easily evaporated, which greatly shortens the life of the hot electron emitter. Carbon Nanotube (CNT) is a new type of carbon material, see "Helical Microtubules of Graphitic Carbon", S. Iijima, Nature, vol. 354, p56 (1991). Carbon nanotubes have excellent electrical conductivity, good chemical stability and large aspect ratio, and have a high The mechanical strength, and thus the carbon nanotubes have potential applications in the field of thermal emission vacuum electron sources. Liu Peng et al. provide a thermal emission electron source based on carbon nanotubes, see "Thermionic emission and work Ο function of Multiwalled carbon nanotube yarns", Peng Liu et al, PHYSICAL REVIEW B, Vol73, P235412-l (2006). The thermal emission electron source uses a long carbon nanotube wire as a source of thermal emission electrons, because the carbon nanotubes have a higher Mechanical strength, so the heat-emitting electron source has a long life, however, since the carbon nanotube has a high work function (4.54-4.64 electron volts), The emission electron source has low emission efficiency, and can emit electrons when the temperature of the long carbon nanotube line reaches 2000 ° C. Therefore, it is difficult to obtain a higher thermal emission current density at a lower temperature. A long-life, heat-emitting electron source capable of emitting 200945401 electrons at a relatively low temperature and having a high emission efficiency is necessary. [A SUMMARY] A heat-emitting electron source includes a carbon nanotube strand, wherein The carbon nanotube strand comprises a plurality of intertwined carbon nanotubes, the heat-emitting electron source further comprising low work function material particles, the low work function material particles being at least partially filled in the carbon nanotube strand . Compared with the prior art, the low-emission work material in the thermal emission electron source provided by the technical solution is filled in the carbon nanotube stranded wire, and is firmly combined with the nano carbon tube stranded wire, and is not easy to fall off, so the heat-emitting electron The source life is longer. Moreover, the low work function material enables the heat emission electron source to emit electrons at a relatively high temperature, and thus the heat emission electron source emits more efficiently than =. In addition, the heat-emitting electron source can be widely used in instruments such as vacuum fluorescent displays, X-ray tubes, and electronic chambers. [Embodiment] Hereinafter, the present technology will be described in detail with reference to the accompanying drawings. The technical solution of the present invention provides a seeding: 1〇, including at least one carbon nanotube strand 12, and the heat emission 2 further includes a plurality A low work function material 钐 work; P low face. : evenly distributed inside the carbon nanotube strand 12 or the surface of the surface, ± (four) Wei electron source i bungee 16 and a first - first less than a first first electrode - the first electrode 16 and a first The two electrodes 18 are placed at both ends of the heat-emitting electron source 1G and are electrically connected to both ends of the heat-emitting electron source 10, and the two ends of the heat-emitting electron source 1〇 can be adhered to by the conductive adhesive. The first electrode 16 and a second electrode 18 are provided. The electrode material may be selected from a conductive material such as gold, silver, copper, carbon nanotubes or graphite. The specific structure of the first electrode 16 and the second electrode 18 is not limited. In this embodiment, the first electrode 16 and the second electrode 18 are preferably a copper block having a rectangular parallelepiped structure, and two ends of the heat-emitting electron source 10 are respectively adhered to the first electrode 16 and the second electrode 18 by silver glue to realize a heat-emitting electron source. The first electrode 16 and the second electrode 18 are electrically connected. The first electrode "and the second electrode U are used to electrically connect the heat-emitting electron source 1" to an external circuit, so that the heat-emitting electron source 10 is more convenient in application. ★ The carbon nanotube strand 12 includes a plurality of Intertwined carbon nanotubes, carbon nanotubes are evenly distributed in the carbon nanotube strands 12, and the carbon nanotubes are tightly coupled by van der Waals force. The carbon nanotube strands have a diameter of 20 Micron - 1 mm. The nanometer carbon tube in the carbon nanotube strand 12 is a mixture of a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon, or any combination thereof. The diameter of a single-walled carbon nanotube is 〇5 奈, the diameter of the double-walled nano tube is (four) nanometer, the diameter of the multi-wall carbon nanotube is 1.5-50 nm, and the length of the carbon nanotube is 1 〇 micrometer (9) micrometers. The low work function material particles 14 are a mixture of cerium oxide particles, cerium oxide particles, calcium oxide particles, barium boride particles, barium boride particles or any combination thereof, the low work function The diameter of the material particles 14 is 1 〇 〇〇 micron. Please refer to FIG. 2 for at least the low work function material particles 14 Fill 9 200945401 == Line 12 inside. Low work function material::, the quality of the strand 12 is 5. It is understood that the structural relationship with the carbon nanotube strand 12 includes the following three == condition: When the diameter of the work function material particles 14 is smaller than the filling: nano carbon two straight two inner = _ = ^ :: - partially filled in the carbon nanotube strands β particles 14 another part in the carbon nanotube strand 12 Surface; the second one = work (four) age 14 can also be completely distributed in the carbon nanotubes two " = low work function material particles 14 at least partially filled with nano carbon; line work function material particles 14 and nano Carbon tube stranding is more (4). The heat-emitting electron source Η) the temperature at which electrons are emitted is related to the quality of the material particles 14. Low-emission work material particle low-emission force heat-emitting electron source 1〇 The lower the temperature at which electrons are emitted, the lower the mass === the lower the emission temperature of the heat-emitting electron source, the lower the emission temperature can be 80 (^ Heat-emitting electron source 10 Further, two or more of the nano-strands 12 of at least the inner material particles 14 may be twisted with each other to entangle the heat-emitting electron source 10'. The heat-emitting electron source 1G has a larger diameter, which is convenient Applied to the macroscopic field, and the heat-emitting electron source 1 is relatively long-lived. % In step-at least - at least the inner carbon nanotubes 12 filled with low-flow function material particles 14 and at least - wires (Fig. 2) The two twisted and twisted forming-composite 纟 5C line structure, the composite stranded wire structure as a thermal emission 200945401 electron source ίο can have greater strength and longer life. The material of the wire is not limited, it can be gold, A conductive substance such as silver, copper, or graphite.
應用時，在熱發射電子源10的兩端加一定的電壓， 或在第一電極16和第二電極18之間施加一定的電壓， 該電壓使奈米碳管絞線12中產生電流，由於焦耳熱的作 用，使奈米碳管絞線12逐漸升溫，奈米碳管絞線、12將 熱量傳遞給低逸出功材料卿14，該低逸出功材料顆粒 内邛的電子隨著溫度的升高能量逐漸增加，當熱發射 電子源10的溫度達到80(rc左右時，電子的能量^出低 逸出功材料顆粒14的逸出功，便從該低逸出功 14内逸出，即該熱發射電子源1〇發射出電子。 粒In application, a certain voltage is applied across the heat-emitting electron source 10, or a certain voltage is applied between the first electrode 16 and the second electrode 18, which causes a current to be generated in the carbon nanotube strand 12 due to The action of Joule heat causes the carbon nanotube strand 12 to gradually heat up, and the carbon nanotube strands 12 transfer heat to the low work function material 14. The electrons in the low work function material particles follow the temperature. The rising energy is gradually increased, and when the temperature of the heat-emitting electron source 10 reaches about 80 (rc), the energy of the electrons is low and the work function of the particles of the work-releasing material 14 is released, and the low-emission work 14 escapes. That is, the heat-emitting electron source 1 〇 emits electrons.
本技術方案所提供的熱發射電子源1〇存在以下優 點：其一，熱發射電子源10中的低逸出功材料顆粒Η 使該熱發射電子源1〇開始發射電子的溫度降低，提高了 熱發射電子源10的熱發射效率；其二，低逸出功材料顆 粒14填充於奈米碳管絞線12内、附著在奈米碳管絞線 12表面且均勻分佈，與奈米碳管絞線12結合牢固，不易 脫落:因此該熱發射電子源1〇的壽命較長；其三，由於 奈米碳管絞線12的比表面積較大，可使較多的逸出功材 料顆粒Μ填充於奈米碳管絞線12 β、附著在奈米碳管 奴線12表面且均勻分佈（逸出功材料顆粒14的質量為 奈米碳管絞線12的5G%_9G%)，顯著降低熱發射電子源 10發射電子時的溫度（可最低降至8〇〇。匚）。 、 請參閱圖2,本技術方案實施例提供一種製備上述執 發射電子源10的方法，具體包括以下步驟： … 11 200945401 步驟一：提供一奈米碳管薄膜。 該奈米碳管薄膜的製備方法包括以下步驟： ' 首先’提供一奈米碳管陣列形成於一基底，優選地， 該陣列為定向排列的奈米碳管陣列。 本技術方案實施例提供的奈米碳管陣列為單壁奈米 碳管陣列、雙壁奈米碳管陣列及多壁奈米碳管陣列^的 一種。該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：（a)提供一平整基底，該基底可選 〇用P型或N型矽基底，或選用形成有氧化層的矽基底， 本技術方案實施例優選為採用4英寸的梦基底；（b)在 基底表面均勻形成一催化劑層，該催化劑層材料可選用 鐵（Fe )、鈷（Co )、鎳（Ni )或其任意組合的合金之一； (c)將上述形成有催化劑層的基底在7〇CrC-90(rc的空 氣中退火約30分鐘-90分鐘；（d)將處理過的基底置於 反應爐中，在保護氣體環境下加熱到5〇〇°c _740°C，然後 通入碳源氣體反應約5分鐘-30分鐘，生長得到奈来碳管 ©陣列。該奈米碳管陣列為複數個彼此平行且垂直於基底 生長的奈米碳管形成的純奈米碳管陣列。通過上述控制 生長條件，該定向排列的奈米碳管陣列中基本不含有雜 質’如無定型碳或殘留的催化劑金屬顆粒等。 本技術方案實施例中碳源氣可選用乙炔、乙烯等化學 性質較活潑的碳氫化合物，本技術方案實施例優選的碳 源氣為乙炔’·保護氣體為氮氣或惰性氣體，本技術方案 實施例優選的保護氣體為氬氣。 可以理解，本技術方案實施例提供的奈米碳管陣列不 12 200945401 限於上述製備方法， ，法m發沈積法等等為墨電極“電弧放電沈積 ΐΐ二用 Λ 述奈米碳管陣列製備-奈米碳管薄膜。 法種為擠壓方法。絮化方法包括以下步驟： 底刮落一，獲得用一刀奈片 ❹米。所述之奈米碳管原料中，奈米碳管的長度大於職 化處(理二獲)得將上= 奈米碳管料添加到—溶财並進行絮 匕，理獲奈米碳f絮狀結構，將上 結構從溶劑中分離，並對太 戾官糸狀 以獲得-奈米碳管^對^好絮狀結敎型處理 本技術方案實施例中，溶劑可選用 溶劑等。絮化處理可通過採用招罄冰八私：輝發的有機 ^ 分散處理或高強度 ❾二气: 本技術方案實施例採用超聲波分 刀鐘〇为鐘。由於奈米碳管具有極大的比表面積， 相互纏繞的奈米碳管之間具有較大的凡德瓦爾力。上述 絮化處理並不會將該奈米碳管原料中的奈米碳管完全八 散在溶劑中，奈米碳管之間通過凡德瓦爾力相互吸引: 纏繞，形成網路狀結構。 本技術方案實施例中，所述之分離奈米碳管絮狀結構 的方法具體包括以下步驟··將上述含有奈米碳管絮^結 構的溶劑倒入一放有濾紙的漏斗中；靜置乾燥一段時^ 從而獲得一分離的奈米碳管絮狀結構。 13 200945401 本技術方案實施例中，所述之奈米 型處理過程具體包括以下步m = 構的疋 播署於一哭+ 述奈米碳管絮狀結 :二一:一二;f該奈米碳管絮狀結構按照預定形狀 攤開，知加-疋壓力於攤開的奈米碳管絮狀結構；以及， :該奈米碳管絮狀結構中殘留的溶㈣乾或等溶劑自然 揮發後獲得一奈米碳管薄膜。 可以理解，本技術方案實_可通過㈣該奈米碳管 絮狀結構攤開的面積來控制該奈米碳管薄膜的厚度和麵 =°奈米碳管絮狀結構„的面積越大，則該奈米碳 g溥膜的厚度和麵密度就越小。本技術方案實施例中獲 付的奈求碳管薄膜，該奈米碳管薄膜的厚度& i微米_2 毫米。 另外，上述分離與定型處理奈米碳管絮狀結構的步驟 也可直接通過抽濾的方式實現，具體包括以下步驟：提 供微孔濾膜及一抽氣漏斗；將上述含有奈米碳管絮狀 結構的溶劑經過該微孔濾膜倒入該抽氣漏斗中；抽濾並 乾燥後獲得一奈米碳管薄膜。該微孔濾膜為一表面光 滑、孔徑為0.22微米的濾膜。由於抽濾方式本身將提供 一較大的氣壓作用於該奈米碳管絮狀結構，該奈米碳管 絮狀結構經過抽濾會直接形成一均勻的奈米碳管薄膜。 且，由於微孔濾膜表面光滑，該奈米碳管薄膜容易剝離。 上述奈米碳管薄膜中包括相互纏繞的奈米碳管，所述 奈米碳管之間通過凡德瓦爾力相互吸引、纏繞，形成網 路狀結構，因此該奈米碳管薄膜具有很好的韌性。該奈 米碳管薄膜中，奈米碳管為各向同性，均勻分佈，無規 14 200945401 則排列。 所述之採用擠麗方法製備奈米碳管薄膜的過 用一施壓裝置，擠壓上述奈米碳管陣列獲得一夺與 薄膜，其具體過程為： 不/、厌& 該施壓裝置施加一定的壓力於上述奈采碳管 上。在施壓的過程中，奈米碳管陣列在壓力的作用下 與生長的基底分離，從而形成由複數個奈米碳管組 具有自支撐結構的奈米碳管薄膜，且所述之複數個奈米 碳管基本上與奈米碳管薄膜的表面平行。本技術方^實 施例中’㈣裝置為一壓帛，壓頭表面光㉟，壓頭的形 狀及擠壓方向決定製備的奈来碳管薄膜中奈米碳管的排 列方式。具體地，當採用平面壓頭沿垂直於上述奈米碳 管陣列生長的基底的方向擠壓時，可獲得奈米碳管為各 向同性排列的奈米碳管薄膜；當採用滾軸狀壓頭沿某一 固定方向㈣時，可獲得奈米碳管沿該固定方向取向排 ❹ 列的奈米碳管薄膜；當採用滾軸狀壓頭沿不同方向碾壓 時，可獲得奈米碳管沿不同方向取向排列的奈米碳管薄 膜0 可以理解，當採用上述不同方式擠壓上述的奈米碳管 陣列，」奈米碳管會在壓力的作用下傾倒，並與相鄰的 奈^碳管通過凡德瓦爾力相互吸引、連接形成由複數個 奈米妷官組成的具有自支撐結構的奈米碳管薄膜。所述 之複數個奈米碳管與該奈米碳管薄膜的表面基本平行並 為各向同性或沿一固定方向取向或不同方向取向排列。 另外，在壓力的作用下，奈米碳管陣列會與生長的基底 15 200945401 分離，從而使得該奈米碳管薄膜容易與基底脫離。 本技術領域技術人員應明白，上述奈米碳管陣列的傾 倒程度（傾角）與壓力的大小有關，壓力越大，傾角越 大。製備的奈米碳管薄膜的厚度取決於奈米碳管陣列的 高度以及壓力大小。奈米碳管陣列的高度越大而施加的 壓力越小，則製備的奈米碳管薄膜的厚度越大；反之， 奈米碳管陣列的高度越小而施加的壓力越大，則製備的 奈米碳管薄膜的厚度越小。該奈米碳管薄膜的寬度與奈 ❾来碳管陣列所生長的基底的尺寸有關，該奈米碳管^膜 的長度不限，可根據實際需求制得。本技術方案實施例 中獲得的奈米碳管薄膜，該奈米碳管薄膜的厚度為工微 米-2毫米。 上述奈米碳管薄膜中包括複數個沿同一方向或擇優 取向排列的奈米碳管，所述奈米碳管之間通過凡德瓦爾 力相互吸引，因此該奈米碳管薄膜具有很好的韌性。該 奈米碳管薄膜中’奈米碳管均勻分佈，規則排列。 ❹ 可以理解’本技術方案實施例中該奈米碳管薄膜可根 據實際應用切割成預定的形狀和尺寸，以擴大盆應用^ 圍。 步驟二，提供一含有低逸出功材料或者低逸出功材料 前驅物的溶液，採用此溶液浸潤上述奈米碳管薄膜。 通過試管將溶液不斷液滴落於奈米碳管薄膜表面丄 秒-0.5分鐘，或者將奈米碳管薄膜浸入溶液_ i秒_〇 $八 鐘。 •刀 所述低逸出功材料的前驅物為可於一定溫度下分解 16 200945401 生成相應低逸出功材料的物質，如低逸出功材料屬於金 屬氧化物時，則低逸出功材料前驅物可選用該氣 物所對應的鹽類。 ％ 所述溶液的溶劑的具體成分不限，其可以溶解低逸出 功材料的前驅物形成溶液即可，該溶劑包括水、乙醇、 甲醇、丙酮或其混合物。 ❹ ❿ 所述低逸出功材料的前驅物包括罐酸鎖、石肖酸鎮或确 酸約等可形成低溢出功材料的物質。 本實施例中，所述溶液的溶質優選為硝酸鋇、硝酸勰 和石肖⑽的混合物’其摩爾比優選為1:1:請，溶劑優選 為，積比為1:1的去離子水與乙醇的混合物。氧化錯顆粒 顆粒可降低熱發射電子源1〇的逸出功和熱發射 電子源ίο於尚溫工作時氧化鎖顆粒的蒸發率，且可以提 咼該熱發射電子源1〇的抗燒結能力。 =液浸潤後的奈米碳管薄膜中，溶液包覆於奈米碳管 薄膜中奈米碳管的表面。 、步驟三：採用機械方法處理浸潤後的奈米碳管薄膜形 成一奈米碳管絞線12。 米：管薄膜的一端枯附於一工具上，以一定的速 具，將該奈米碳管薄膜擰成—奈米碳管絞線 可U理解’上述工具的旋轉方式不限，可以正 可以反轉。 付也 本實把例中，所述工具為一紡紗軸，將該其 膜的-端與紡紗軸結合後，卩鳩轉紛鐘速度^轉二纺 17 200945401 紗軸3分鐘’即得到一奈米碳管絞線i2。 十述機Μ方法處理奈米碳管薄冑的過帛中，由於 薄膜中的奈米碳管的表面包覆有含有低逸出功料斗 處理太乎墟其： 因此，經過機械方法 3 =管薄膜得到奈米碳管絞線12後，該溶液填充 本不米峡纽線12的内部或分佈於奈米碳管絞線^ 表面。 〃The heat-emitting electron source 1 provided by the present technical solution has the following advantages: First, the low-emission work material particles in the heat-emitting electron source 10 cause the temperature of the heat-emitting electron source 1 to start emitting electrons to decrease, thereby improving the temperature. The thermal emission efficiency of the thermal emission electron source 10; secondly, the low work function material particles 14 are filled in the carbon nanotube strand 12, adhered to the surface of the carbon nanotube strand 12 and uniformly distributed, and the carbon nanotube The stranded wire 12 is firmly bonded and is not easy to fall off: therefore, the life of the heat-emitting electron source 1〇 is long; and thirdly, because the specific surface area of the carbon nanotube strand 12 is large, more particles of the working material can be produced. Filled in the carbon nanotube strand 12 β, attached to the surface of the carbon nanotube line 12 and evenly distributed (the mass of the work material particle 14 is 5G%_9G% of the carbon nanotube strand 12), which is significantly reduced The temperature at which the heat-emitting electron source 10 emits electrons (can be reduced to a minimum of 8 〇〇. 匚). Referring to FIG. 2, an embodiment of the present technical solution provides a method for preparing the above-mentioned electron-emitting source 10, which specifically includes the following steps: ... 11 200945401 Step 1: Providing a carbon nanotube film. The method of preparing the carbon nanotube film comprises the steps of: 'First' providing a carbon nanotube array formed on a substrate, preferably the array is an array of aligned carbon nanotubes. The carbon nanotube array provided by the embodiment of the present technical solution is a single-walled carbon nanotube array, a double-walled carbon nanotube array, and a multi-walled carbon nanotube array. The method for preparing the carbon nanotube array adopts a chemical vapor deposition method, and the specific steps thereof include: (a) providing a flat substrate, the substrate optionally using a P-type or N-type germanium substrate, or an oxide layer formed thereon.矽 substrate, the embodiment of the technical solution is preferably a 4-inch dream substrate; (b) uniformly forming a catalyst layer on the surface of the substrate, the catalyst layer material may be selected from iron (Fe), cobalt (Co), nickel (Ni) or One of the alloys of any combination thereof; (c) annealing the substrate on which the catalyst layer is formed in the air of 7 〇CrC-90 (rc for about 30 minutes to 90 minutes; (d) placing the treated substrate in the reaction furnace In the protective gas atmosphere, it is heated to 5 〇〇 ° _ 740 ° C, and then the carbon source gas is introduced for about 5 minutes to 30 minutes to grow to obtain a carbon nanotube array. The carbon nanotube array is plural. a pure carbon nanotube array formed of carbon nanotubes grown parallel to each other and perpendicular to the substrate. The aligned carbon nanotube array contains substantially no impurities such as amorphous carbon or residual catalyst by controlling the growth conditions described above. Metal particles, etc. In the embodiment, the carbon source gas may be a chemically active hydrocarbon such as acetylene or ethylene. The preferred carbon source gas in the embodiment of the present invention is acetylene'. The shielding gas is nitrogen or an inert gas, and the embodiment of the present invention is preferred. The protective gas is argon. It can be understood that the carbon nanotube array provided by the embodiments of the present technical solution is not limited to the above preparation method, the m-deposition method, etc. is an ink electrode "arc discharge deposition" Rice carbon tube array preparation - nano carbon tube film. The method is an extrusion method. The flocculation method comprises the following steps: bottom scraping one, obtaining a glutinous rice with a knife. The nano carbon tube raw material, nai The length of the carbon tube is greater than that of the occupational department (the second is obtained). The upper carbon nanotube is added to the solvent and flocculated, and the nano carbon f floc structure is obtained to separate the upper structure from the solvent. And the 戾 戾 以获得 - 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 奈 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好 好Huifa's organic ^ dispersion Or high-intensity enthalpy gas: The embodiment of the technical solution adopts an ultrasonic splitting knife clock as a clock. Since the carbon nanotube has a large specific surface area, a large van der Waals force is interposed between the intertwined carbon nanotubes. The above flocculation treatment does not completely disperse the carbon nanotubes in the carbon nanotube raw material in the solvent, and the carbon nanotubes are mutually attracted by the van der Waals force: entanglement to form a network structure. In the embodiment, the method for separating the carbon nanotube floc structure comprises the following steps: pouring the solvent containing the carbon nanotube structure into a funnel with a filter paper; In order to obtain a separate carbon nanotube floc structure. 13 200945401 In the embodiment of the technical solution, the nano type processing process specifically includes the following steps: m = configuration of the 署 broadcast in a cry + naimi Carbon tube flocculent knot: two one: one two; f the carbon nanotube floc structure is spread according to a predetermined shape, knowing the pressure of the carbon nanotube floc structure; and: the nanometer Solvent (tetra) dry or equivalent solvent remaining in the carbon tube floc structure A natural carbon nanotube film is obtained after natural evaporation. It can be understood that the technical solution can control the thickness of the carbon nanotube film and the area of the surface of the carbon nanotube film by the area spread by the carbon nanotube floc structure. Then, the thickness and the areal density of the nano-carbon film are smaller. In the embodiment of the present invention, the carbon nanotube film is obtained, and the thickness of the carbon nanotube film is < i μm 2 mm. The step of separating and shaping the carbon nanotube floc structure can also be directly carried out by suction filtration, and specifically includes the following steps: providing a microporous membrane and an extraction funnel; and the above-mentioned carbon nanotube-containing floc structure The solvent is poured into the suction funnel through the microporous membrane; after suction filtration and drying, a carbon nanotube film is obtained. The microporous membrane is a filter membrane having a smooth surface and a pore size of 0.22 μm. The method itself will provide a large gas pressure on the carbon nanotube floc structure, and the carbon nanotube floc structure will directly form a uniform carbon nanotube film by suction filtration. Moreover, due to the microporous membrane Smooth surface, the carbon nanotube film is easy to peel off The carbon nanotube film comprises intertwined carbon nanotubes, and the carbon nanotubes are mutually attracted and entangled by van der Waals force to form a network structure, so the carbon nanotube film has a good The toughness. In the carbon nanotube film, the carbon nanotubes are isotropic and evenly distributed, and the random 14 is arranged in 2009. The above-mentioned pressure-applying device for preparing the carbon nanotube film by the squeeze method is used. Extrusion of the above-mentioned carbon nanotube array to obtain a film and a specific process is as follows: No/, anoxia & The pressure applying device applies a certain pressure to the above-mentioned carbon nanotubes. During the pressure application, Nai The carbon nanotube array is separated from the grown substrate by pressure to form a carbon nanotube film having a self-supporting structure composed of a plurality of carbon nanotube groups, and the plurality of carbon nanotubes are substantially The surface of the carbon nanotube film is parallel. In the embodiment of the present invention, the '(4) device is a pressure, the surface light 35 of the indenter, the shape of the indenter and the extrusion direction determine the carbon nanotubes in the prepared carbon nanotube film. Arrange the way. Specifically, when When the planar indenter is extruded in a direction perpendicular to the substrate grown by the carbon nanotube array, a carbon nanotube film is obtained which is isotropically arranged; when a roller-shaped indenter is used along a certain In the fixed direction (4), the carbon nanotube film in which the carbon nanotubes are oriented in the fixed direction can be obtained; when the roller-shaped indenter is rolled in different directions, the carbon nanotubes can be oriented in different directions. Arranged carbon nanotube film 0 It can be understood that when the above-mentioned carbon nanotube array is extruded by the above different methods, the carbon nanotubes will be poured under the action of pressure and passed through the adjacent carbon nanotubes. Devalli attracts and joins each other to form a carbon nanotube film with a self-supporting structure composed of a plurality of nano sergeants. The plurality of carbon nanotubes are substantially parallel to the surface of the carbon nanotube film and are isotropic or oriented in a fixed direction or in different directions. In addition, under the action of pressure, the carbon nanotube array is separated from the grown substrate 15 200945401, so that the carbon nanotube film is easily detached from the substrate. Those skilled in the art will appreciate that the degree of tilt (inclination) of the carbon nanotube array described above is related to the magnitude of the pressure, and the greater the pressure, the greater the angle of inclination. The thickness of the prepared carbon nanotube film depends on the height of the carbon nanotube array and the magnitude of the pressure. The higher the height of the carbon nanotube array and the lower the applied pressure, the greater the thickness of the prepared carbon nanotube film; conversely, the smaller the height of the carbon nanotube array and the higher the applied pressure, the prepared The smaller the thickness of the carbon nanotube film. The width of the carbon nanotube film is related to the size of the substrate on which the carbon nanotube array is grown. The length of the carbon nanotube film is not limited and can be obtained according to actual needs. In the carbon nanotube film obtained in the embodiment of the technical solution, the carbon nanotube film has a thickness of -2 mm. The carbon nanotube film includes a plurality of carbon nanotubes arranged in the same direction or in a preferred orientation, and the carbon nanotubes are mutually attracted by van der Waals force, so the carbon nanotube film has a good toughness. The carbon nanotubes in the carbon nanotube film are uniformly distributed and regularly arranged. ❹ It can be understood that the carbon nanotube film in the embodiment of the present technical solution can be cut into a predetermined shape and size according to practical applications to expand the pot application. In the second step, a solution containing a low work function material or a precursor of a low work function material is provided, and the above carbon nanotube film is infiltrated with the solution. The solution was continuously dropped on the surface of the carbon nanotube film by a test tube for 丄 second - 0.5 minutes, or the carbon nanotube film was immersed in the solution _ i seconds _ 〇 $8. • The precursor of the low work function material is a substance that can decompose 16 200945401 to generate a corresponding low work function material at a certain temperature. For example, when the low work function material belongs to metal oxide, the precursor of low work function material is precursor. The salt corresponding to the gas can be selected. % The specific component of the solvent of the solution is not limited, and it may dissolve a precursor forming solution of a low work function material including water, ethanol, methanol, acetone or a mixture thereof.前 前 The precursor of the low work function material includes a substance such as a tank acid lock, a sulphur acid acid or a sulphuric acid material which can form a low overflow work material. In this embodiment, the solute of the solution is preferably a mixture of cerium nitrate, cerium nitrate and lithograph (10), wherein the molar ratio is preferably 1:1: please, the solvent is preferably a deionized water having a 1:1 ratio. a mixture of ethanol. Oxidation of the wrong particles The particles can reduce the work function of the heat-emitting electron source and the thermal emission electron source. The evaporation rate of the oxidation-locking particles during the operation of the temperature can be improved, and the anti-sintering ability of the heat-emitting electron source can be improved. = In the carbon nanotube film after liquid infiltration, the solution is coated on the surface of the carbon nanotube in the carbon nanotube film. Step 3: Mechanically treating the infiltrated carbon nanotube film to form a nano carbon tube strand 12. M: One end of the tube film is attached to a tool, and the carbon nanotube film is twisted into a certain speed tool. The carbon nanotube strand can be understood by the above-mentioned tool. Reverse. In the example of the present invention, the tool is a spinning shaft, and the end of the film is combined with the spinning shaft, and the speed of the winding is turned to the second spinning 17 200945401 yarn shaft for 3 minutes. One nano carbon tube strand i2. The ten-machine method is used to treat the carbon nanotubes in a thin crucible. Because the surface of the carbon nanotubes in the film is coated with a low-emission hopper, it is too expensive: therefore, after mechanical means 3 = tube After the film is obtained from the carbon nanotube strands 12, the solution fills the interior of the Ben-Gorge line 12 or is distributed on the surface of the carbon nanotube strands. 〃
步驟四：烘乾該奈米碳管絞線12。 。將上述的奈米碳管絞、線12放置於空氣中，於1〇(Μ〇〇 =下供乾該奈米碳管絞線12。本實施射，將上述奈米碳 g絞線12置於空氣中’於溫度為⑽。c下烘乾w分鐘 >此過程中’填充於奈米碳管絞線12内或分佈於奈米 炭&絞線12表面的溶液中的溶劑完全揮發，溶質以顆粒的 =式填充於奈米碳管輯12内、附著於奈米碳管絞線η 面且均勻分佈於奈米碳管絞線12的内部和表面。可以 解， ,本實靶例中，汶潤於奈米碳管絞線12中的硝酸鋇、 肖酸“和《肖酸舞的混合溶液的溶劑完全揮發，溶質硝酸 鎖、硝酸師石肖酸㈣顆粒的形式填充於奈米破管絞線12 内、附著於奈米碳管絞線12表面且均勻分佈。 步驟五：激活上述烘乾後的奈米碳管絞線12，即得 到熱發射電子源10。 2將上述烘乾後的奈米碳管絞線12放置於一壓強為丄 X10帕_1χ1〇帕真空系統中，於奈米碳管絞線的兩端施 加電C，使该奈米碳官絞線的溫度達到8〇〇14〇〇。匸，持 18 200945401 續1分鐘-1小時，得到熱發射電子源10。 本實施例中，將上述烘乾後的奈米碳管絞線置於 .壓強為ixl〇_4帕的真空系統中，於該奈米碳管絞線12的 兩端施加電壓，使奈米碳管絞線12的溫度達到1000ΐ， 持續20分鐘。通常，溫度越高時，所需激活時間越短。此 過程中，硝酸鋇顆粒、硝酸锶顆粒和硝酸鈣顆粒分解生成 氧化鋇顆粒、氧化錫顆粒和氧化辦顆粒，其直徑為奈米 -100微米，填充於奈米碳管絞線12内、附著於奈米^管 絞線12表面且均勻分佈。真空高溫環境可除去該奈米碳管 絞線12表面的氣體，該氣體包括水蒸氣、二氧化碳等。將 該奈米碳管絞線12從真空系統中取出，即得到熱發 源10。 激活的目的係為了降低熱發射電子源10的逸出功， 可以使其於較低的溫度下發射電子。 一可選擇地，上述熱發射電子源10的製備方法還可進 ❹二t包括—將至少兩個激活後的奈米碳f絞線12通過機 械外力擰成-絞線結構的熱發射電子源1G的步驟，該 射電子源1〇尹，至少兩個奈米碳營絞線12相互扭曲纏繞。 可選擇地，上述熱發射電子源1〇的製備方法還可進 一步包括一將至少-個激活後的奈米碳管絞線！2與至少 -導線通過機械外力擰成—複合絞線結構的熱電 二的步驟，該熱發射電子源1〇中，奈米碳管_12 J , 導線相互扭曲纏繞。 可選擇地，還可進—舟白杯 的而嫂你访―步包括述熱發射電子源10 、第-電極16和第二電極18分別電性連接的步 19 200945401 驟，可以通過導電膠，將第一電極16和第二電極18粘 附於熱發射電子源10的兩端’與第一電極16和第二電 ' 極18電性連接。 綜上所述，本發明確已符合發明專利之要件，遂依法 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 φ 蓋於以下申請專利範圍内。 【圖式簡單說明】 圖1係本技術方案實施例的熱發射電子源的結構示意 圖。 圖2係本技術方案實施例的熱發射電子源的掃描電鏡 照片。 圖3係本技術方案實施例的熱發射電子源的製備方法 Q 的流程圖。 【主要元件符號說明】 熱發射電子源 10 奈米碳管絞線 12 低溢出功材料顆粒 14 第一電極 16 第二電極 18 20Step 4: Dry the carbon nanotube strand 12 . . The above-mentioned carbon nanotube strands and wires 12 are placed in the air, and the nano carbon tube strands 12 are supplied for drying at 1 Torr (this = the above-mentioned nano carbon g strands 12 are placed) In the air, 'at a temperature of (10). c drying for w minutes> during this process, the solvent filled in the carbon nanotube strand 12 or distributed in the surface of the nanocarbon & strand 12 is completely volatilized. The solute is filled in the carbon nanotubes 12 in the form of particles, attached to the n-plane of the carbon nanotube strands, and evenly distributed inside and on the surface of the carbon nanotube strand 12. The solution can be solved. In the example, Wenrun's yttrium nitrate and succinic acid in the carbon nanotube strand 12 are completely evaporated in the solvent of the mixed solution of the xiao acid dance, and the solute nitrate lock and the nitrate sulphuric acid (tetra) granule are filled in the form of granules. The inside of the stranded strand 12 is attached to the surface of the carbon nanotube strand 12 and uniformly distributed. Step 5: Activate the above-mentioned dried carbon nanotube strand 12 to obtain a heat-emitting electron source 10. 2 The dried carbon nanotube strand 12 is placed in a vacuum system of 丄X10 Pa_1χ1〇帕, and is applied at both ends of the carbon nanotube strand. Electric C, the temperature of the carbon carbon stranded wire reaches 8〇〇14〇〇.匸, hold 18 200945401 for 1 minute to 1 hour, to obtain a thermal emission electron source 10. In this embodiment, after the above drying The carbon nanotube strand is placed in a vacuum system with a pressure of ixl 〇 _ 4 Pa, and a voltage is applied across the carbon nanotube strand 12 to bring the temperature of the carbon nanotube strand 12 to 1000 ΐ. For 20 minutes. Generally, the higher the temperature, the shorter the activation time required. In this process, cerium nitrate particles, cerium nitrate particles and calcium nitrate particles are decomposed to form cerium oxide particles, tin oxide particles and oxidation particles, the diameter of which is The nano-100 micron is filled in the carbon nanotube strand 12 and adhered to the surface of the nano tube strand 12 and uniformly distributed. The vacuum high temperature environment can remove the gas on the surface of the nano carbon tube strand 12, the gas Including water vapor, carbon dioxide, etc. The carbon nanotube strand 12 is taken out of the vacuum system to obtain a heat source 10. The purpose of activation is to lower the work function of the heat-emitting electron source 10, which may make it lower. Emission of electrons at a temperature. Alternatively, on The method for preparing the heat-emitting electron source 10 may further include the step of twisting at least two activated nanocarbon f strands 12 into a heat-emitting electron source 1G of a stranded structure by mechanical external force, the shot The electron source 1〇尹, at least two nano carbon camp strands 12 are twisted and twisted with each other. Alternatively, the method for preparing the above-mentioned heat-emitting electron source 1〇 may further include at least one activated carbon nanotube The twisted wire! 2 and at least the wire are twisted by mechanical external force into a thermoelectric circuit of a composite stranded wire structure in which the carbon nanotubes _12 J and the wires are twisted and twisted with each other. Alternatively, It is also possible to enter the boat-white cup and visit the step-by-step including the thermal emission electron source 10, the first electrode 16 and the second electrode 18 respectively electrically connected to step 19 200945401, the first electrode can be passed through the conductive adhesive 16 and the second electrode 18 are adhered to both ends of the heat-emitting electron source 10' to be electrically connected to the first electrode 16 and the second electric pole 18. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description 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. Any equivalent modifications or variations made by those skilled in the art to the spirit of the present invention should be covered by the following claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of a heat-emitting electron source of an embodiment of the present technical solution. 2 is a scanning electron micrograph of a thermally-emitted electron source of an embodiment of the present technical solution. FIG. 3 is a flow chart of a method Q for preparing a thermal emission electron source according to an embodiment of the present technical solution. [Main component symbol description] Thermal emission electron source 10 Nano carbon nanotube stranded wire 12 Low overflow work material particle 14 First electrode 16 Second electrode 18 20