200921753 九、發明說明： 【發明所屬之技術領域】 ' 本發明涉及一種場發射電子源的製備方法，尤其涉及 ' 一種基於奈米碳管的場發射電子源的製備方法。 【先前技術】 場發射電子源在低溫或者室溫下工作，與電真空器件 中的熱發射電子源相比具有能耗低、回應速度快以及低放 電等優點，因此用場發射電子源替代電真空器件中的熱發 射電子源成為了人們研究的一個熱點。 奈米碳管（Carbon Nanotube，CNT)係一種新型碳材 料，由日本研究人員Iijima在1991年發現，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，且其具有幾乎接近理論極 限的尖端表面積（尖端表面積愈小，其局部電場愈集中）， 因而奈米碳管在場發射真空電子源領域具有潛在的應用前 - 景。目前的研究表明，奈米碳管係已知的最好的場發射材 料之一，它的尖端尺寸只有幾奈米至幾十奈米，具有極低 的場發射電壓（小於100伏），可傳輸極大的電流密度，並 且電流極穩定，使用壽命長，因而非常適合作為一種極佳 的點電子源，應用在掃描電子顯微鏡（Scanning Electron Microscope)、透射電子顯微鏡（Transmission Electron Microscope)等設備的電子發射部件中。 先前的奈米碳管場發射電子源一般至少包括一導電基 體和作為發射端的奈米碳管，該奈米碳管形成於該導電基 200921753 :上。目前，奈求碳管形成於導電基體上的方法主要包括 =法和原位生長法。其中，機械方法係通過原子力顯 a、兄或電子顯微鏡#縱早根奈米碳管，將奈米峻管用導雷 膝固定到導電基體上，此種$ 半$ 種方法私式間早，但由於單根奈 未石厌吕尺寸太小，導致操作不容易且效率低。另外， 該方法得到的奈米碳管場發射電子源的場發射電流小。 為克服上述機械法組裝的奈米碳管場發射電子源的場 1射％流小及操作複雜的缺點。先前技術提供了一種 ’=位生長的方法’該方法係先在導電基體上鍍上金屬催化 η然後通過化學氣相沈積、電孤放電或鐘射蒸發法 法在導電基體上直接生長出多根奈米碳管作為場發射兩 :、；：種方法雖然操作簡單’奈米碳管與導電基體的；接 良好。然而，奈米礙管與導電基體的結合能力較弱， 使用時奈米碳管易脫落或被電場力拔出，從而導致場發 電子源損壞。而且，由於該方法無法控制奈米碳管的^ 方向，所以仍存在效率低且可控性差的問題，另外，、言 、^發射電子源結構中多根奈米碳管之間存在電場屏=效 -，工作時往往只有少部分奈米碳管發射電子，亦無法 效提高場發射電子源的電流密度。 …/ 有雲於此，提供一種具有較大的場發射電流的場發射 電子源的製備方法實為必要。 【發明内容】 一種場發射電子源，包括一導電基體和—奈米碳管長 線。該奈米碳管長線具有一第一端以及與第—端相‘二； 7 200921753 一端，該奈米碳管長線的第一端與該導電基體電連接，該 奈米碳=長線的第二端從導電基體向外延伸，該奈米碳管 長線的第二端包括多個突出的場發射尖端。 一種場發射電子源的製備方法，其具體包括以下步 驟：提供一奈米碳管陣列形成於―基底"采用—拉伸工具 ϋ奈米ί!陣列中拉取奈米碳管獲得-奈米碳管薄膜或者 不米石厌g絲’通過使用有機溶劑或者施加機械外力處理 該奈米，膜或者奈米碳管絲得到一奈米碳管長線；將 該奈米石反官長線通電流加熱炫斷，在溶斷處形成多個場發 射尖端；以及將該炫斷後的奈米碳管長線設置體 上即得到場發射電子源。 土體 有以ΐί!技Γ比較，該場發射電子源及其製備方法具 其-，採用了奈米碳管長線作為場發射電子 的、^:2官長線包括多個突出的場發射尖端，所製備 —d射電子源具有較大的場發射電流；其二 :=:!，尖端，有效降低該場； 摔：：，效應；其三，奈米碳管長線為宏觀器件， 知作間早，因此，該場發射電子源的製備方 提尚該場發射電子源的製備效率。 °以 【實施方式】 以下將結合附圖詳細說明，枯 及其製備方法。 月本技街方案場發射電子源 口月參閱圖1，本技術方案實施例 源10,其包括一導電基體14和„ ^^發射電子 不木石反官長線12。該 200921753 奈米破管長線12具有一第一端122以及與第一端ι22相 對的第二端124，該奈米碳管長線12的第一端ι22與該 導電基體14電連接，該奈米碳管長線12的第二端 從導電基體14向外延伸作為電子發射端。 進一步地，所述的奈米碳管長線12係由多個平行的 首尾相連的奈米碳管束組成的束狀結構或由多個首尾相 連的奈米碳管束組成的絞線結構，該相鄰的奈米碳管束 之間通過凡德瓦爾力緊密結合，該奈米碳管束中包括多 個首尾相連且定向排列的奈米碳管。該奈米碳管長線Η 的長度為0.1宅米至1〇毫米，直徑為丄微米至1〇〇微米。 所述的奈米碳管長線12的第二端124為類圓錐形，且豆 直徑沿遠離導電基體14的方向逐漸減小。請參閱圖2Ϊ 該奈米碳管長線12的第二端124包括多個突出的場發射 尖端300。該場發射尖端300包括多個基本平行的太米 管’該多個奈米碳管之間通過凡德瓦爾力緊密結：:、所 述的場發射尖端為類圓錐形。該場發射尖端遍的 頂&突出有一根奈米碳管302。該奈米碳管 為Π)〜奈米石炭管3〇2的尖端直徑小於5奈米。 该奈米碳管長線12 _的夺米& ” T扪不木石厌&為早壁、雙壁或多壁奈 :::。該奈米碳管長線12，的場發射尖端·的頂端 破管緊密結合，使得該場發端的奈米 :二的熱量可以很有效地被傳導出 亚且可以承文較強的電場力。 200921753 請參閱目3，從奈米碳管 描電鏡照片可以看ψ兮中7 电卞^射糙的掃 射„、踹。〜*出該電子發射端包括多個突出的場發 射…凊參閱圖4,從奈米碳管長線 的透射電鏡昭片卜1 , 」电于發射端 5 ，可以看出奈米碳管長線12中的場發 射…了頁端突出有一根奈 少的壁數和更細的古"^ 反s具有更 、的直位，其壁數少於5層一般為2層或 者3層，其直徑通常 ^ ^ 〆 太半石山“ < 吊J於5奈未。而直接生長的超順排 :一反5車列的奈米碳管的層數多於5層，直徑為15奈 米左右0 不 該々導電基體14由導電材料製成，如鎳、銅、鎢、金、 鉬^等。該導電基體14可依實際需要設計成其他形狀， ,、隹形、、、田小的柱形或者圓臺形。該導電基體14也可為 开y成在一絕緣基底上的導電薄膜。 、可以理解，該奈米碳管長線12的第一端122可以通 導電膠與該導電基體14電連接。該電連接的方式也 (可以通過分子間力或者其他方式實現。該奈米碳管長線 =與導電基體14之間的位置關係不限’只需確保該奈米 碳管長線12的第一端122與該導電基體14電連接即可。 如奈米碳管長線12與導電基體14的夾角為銳角，奈米 石反官長線12與導電基體14的夾角為直角或者奈米碳管 長線12與導電基體14的軸向相互平行。 本實施例中，由於採用了奈米碳管長線作為場發射 電子源’該奈米碳管長線包括多個突出的場發射尖端， 所製備的場發射電子源具有較大的場發射電流；而且， 200921753 該奈米碳管長財包括多個場發射尖端，可 該場發射電子源的電場屏蔽效應。 有效降低 發射ϊ:·=5’本技術方案實施例提供-種製備上述場 毛射电子源ίο的方法，具體包括以下步驟： 步驟提供—奈米碳管陣列形成於-基底，優選 地，該陣列為超順排奈米碳管陣列。 =施例中，奈米碳管陣列的製備方法採用化學氣 ，沈積法，其具體步驟包括：（a)提供一平整基底，該基 :可選用P型或N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，該催化劑層材料可選用鐵 (Fe )、鈷（c〇 )、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70(TC〜90(TC的空氣中 退火約30分鐘〜9G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5〇〇艺〜74〇它，然後通入 石反源氣體反應約5分鐘〜30分鐘，生長得到奈米碳管陣 列，其尚度大於100微米。該奈米碳管陣列為多個彼此 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。該奈米碳管陣列與上述基底面積基本相同。通過上 述控制生長條件，該超順排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。 本實施例中碳源氣可選用乙炔、乙烯、曱烷等化學 性質較活潑的碳氫化合物，本實施例優選的碳源氣為乙 快·’保護氣體為氤氣或惰性氣體，本實施例優選的保護 11 200921753 氣體為氬氣。 . 可以理解’本實施例提供的奈米碳管陣列不限於上 •述製備方法。本實施例提供的奈米碳管陣列為單壁夺米 碳管陣列、雙壁奈米碳管陣列及多壁奈米碳管陣列中的 一種。 步驟二：採用一拉伸工具從奈米碳管陣列中拉取夺 米碳管獲得一奈米碳管薄膜或—奈米碳管絲。 , 該奈米複㈣膜或者奈米碳管絲的製備具體包括以 下_( a)從上述奈米碳管陣列中選定一定寬度的多個 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 向拉伸多個該奈米碳管束’以形成—連續的奈米碳管薄 膜或者奈米碳管絲。 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，由於凡德瓦爾力作 用’該選定的多個奈米碳管束分別與其他奈米碳管束首 尾相連地連績地被拉出，從而形成―奈米碳管薄膜或者 奈米碳管絲。該奈米碳管薄膜或者奈米碳管絲包括多 個首尾相連且定向排列的奈米石炭管I。該奈未石炭管薄膜 ，，奈米奴官絲中奈米碳管的排列方向基本平行于奈米 石厌官薄膜或者奈米碳管絲的拉伸方向。 步驟三，通過使用有機溶劑或者施加機械外力處理 該奈米碳管薄膜或者奈米碳管絲得到一奈米碳管長線 12 200921753 所述步驟—中製備的奈米碳管薄膜或者奈米碳管絲 可使用有機溶劑處理得到—奈米碳管長線12。其具體處 理過程包括：通過試管將有機溶劑滴落在奈米碳管薄膜 =奈^管絲表面浸潤整個奈㈣管薄臈或者奈求碳 官絲。可以理解，也可以將上述奈 管絲整個浸入盛有右嬙〜卞ΙΑΛ — 、：3c不未石反 劑的容器中浸潤。該有機溶劑 氣仿X太-劑’如乙醇、甲醇、丙酮、二氯乙烷或 ^仿’本3施例中優選採用乙醇。該奈米碳 ==經有機溶劑浸潤處理後，在揮發性有機溶劑 的表面張力的作爾1 _u . ，不米石反管薄膜或者奈米碳管 :平::奈来碳管片斷會部分聚集成奈米碳管二中 ㈣^碳管薄膜或者奈米碳管絲表面體積比小，盎 理，且具有良好的機械強度及韌性， 觀領域。 錢或者奈米碳管絲方便地應用於宏 斤^乂驟一中製備的奈米碳管薄膜戋者太 也可未妷官絲 供一伽力機械外力處理得到一奈米碳管長線12。提 軸的尾；：：：粘住奈米碳管陣列的紡紗轴。將該紡紗 ==::::列結合後，奈米碳管開始纏繞在 碳管陣列的方:"軸：旋轉的方式旋出並向遠離奈米 ^ 11運動。這時奈米碳管陣列相對於該0 π 繃她 維開始、，方成’其他的奈米碳管可以纏缺i 纖維的周圍，增加纖維的長度。可以理解，上述= 13 200921753 的旋轉方式不限，可以正轉，也可 反轉相結合。 反轉’或者正轉和 . 可以理解，也可以採用—拉伸 碳管陣列中直接拉取奈米碳管獲得—太、； = —的奈米 步驟四：將該奈米舰線12通=?，。 嫁斷處形成多個場發射尖端。 心加熱炫斷，在 該步驟可以在真空環境下或 進行，其具體包括以下步驟： 乳體保遵的每境下 !·" 首先，請參見圖6及圖7 空設置於一真空室5 〇内或充繼？未被官長線12懸 分古〜 円次充滿^性氣體的反應室。 該真工至5 〇包括—ΈΓ iE iE ^ / r-* 陽搞妓“ （圖中未標出）以及- 知極接線柱52與一陰極接線柱 ίο·1帕，優選為2xl(r5帕。該夺0 、，工度低於lx 與陽極接線柱52和险極接線：J長線12兩糊 ^ _ θ 和陰極接線柱^電性連接。本實施例 中’物極接線柱52與陰極接線柱5 毫 v ^ 不未妷官長線12的直徑25微米，長产2 厘米。 I扠没Ζ 斤述的充滿f“生氣體的反應室結構與真空室5〇相 同，惰性氣體可以係氦氣或氬氣等。 /、人在該奈米碳管長線12兩端施加一電壓，通入 電流加熱炫斷。 在陽極接線柱52與陰極接線柱54之間施加一 40伏 特的直流電壓。本技術領域人員應當明白，陽極接線柱 52與陰極接線柱54之間施加的電壓與所選的奈米碳管長 14 200921753 的直彳工和長度錢。在直流條件τ通過焦耳熱加熱 •不米碳官長線12。加熱溫度優選為2〇〇〇〖至24〇〇κ，加 熱^小於1小時。在真空直流加熱過程中，通過奈米 碳管長線12的電流合逐法；：卜4 ..,, Β乙渐上升，但很快電流就開始下降 直到奈米碳管長線12被溶斷。在溶斷前，奈米碳管長線 =會出現一個亮點56，奈米碳管長線12從該亮點56 處溶斷。 ^於奈米碳官長線12中各點的電阻不同，使得各點 的为電壓也不同。在奈米碳管長線12中電阻較大的一 點，會得到較大的分電壓，從而具有較大的加熱功率， 產^較多的焦耳熱，使該點的溫度迅速升高。在溶斷的 過程中’該點的電阻會越來越大，導致該點的分電壓也 越來越大’同4 ’溫度也越來越大直到該點斷裂，形 兩個電子發射端。在熔斷的瞬間，陰極與陽極之間會產 生=個非常小的間隙，同時在熔斷點位置附近，由於碳 的条發’真空度較差’這些因素會使料的瞬間在炼斷 ，附近產生氣體電離。電離後的離子轟擊熔斷的奈米碳 管長線12的端部’並在該端部形成多個場發射尖端^ 本實施例採用的真空溶斷法，避免了奈米碳管長線 12熔斷口的〉可染，而且，加熱過程中奈米碳管長線η的 機械強度會有一定提高’使之具備優良的場發射性能。 步驟五：將熔斷後的奈米碳管長線12設置於—導電 基體14上即得到—場發射電子源1〇。 將熔斷後的奈米碳管長線12通過一導電膠粘附於一 15 200921753 導電基體14之上’即可得到一場發射電子源ι〇。 .可X里解4可將夕個具有電子發射端的奈米碳管 •長線12設置於一導電基體14之上，得到具有多個電子 發射端的場發射電子源。 /本實施例中，由於奈米碳管長線12為宏觀器件，可 以很容易的被粘附於導電基體14上，操作簡$，因此， ^場發射電子源的製備方法簡單，可以提高該場發射電 子源的製備效率。 :參閱圖8，為奈米碳管長線12的場發射尖端_ 石“ j °日圖°用拉哭光譜分析表明經過熱處理的奈米 ^線12的場發射尖端的缺陷峰有明顯的降低， Z =的缺陷峰更低。也就說，奈^炭管長線12的場發 的2 3奈米碳管在溶斷的過程中品質得到了極大 少，=—^方面係由於奈米碳管經過熱處理後缺陷減 潰，剩ΖΓί因為富含缺陷的石墨層容易在高溫下崩 ‘ 下上品質較高的石墨層。 a果 > 閱圖9 ’為上述場發射電子源的場發射性能測試 奈米碳管長線12經過^时斷處理後形成兩 、°該場發㈣子源的場發射性能測試係用 該彳大作為陽極進行測量的，其中該鎢針尖分別與 的尖發射端相對。該嫣針尖與該奈米碳管長線12 子發射端均=距，為100微米。真空炫斷形成的兩個電 該奈米殘管二T供『微安以上的場發射電流。由於 長線12的電子發射端的直徑大約為5微米， 16 200921753 因此該場發射電流的密度大於700安/平方厘米。 β综上所述，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， 自不此以此限制本案之申請專利範圍。舉凡熟悉本案技藝 f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係本技術方案實施例的場發射電子源的結構示意 意圖 圖2係圖1中奈米碳管長線的電子發射端2的放大 恭圖3係本技術方案實施例獲得的奈来碳管長線的電子 毛射端的掃描電鏡照片。 圖4係本技術方案實施例獲得的奈米碳管長線的場發 、尖^頂端的透射電鏡照片。 ^係本技術方案實施例的場發射電子源的製備方法 的程示意圖。 圖^係本技術方案實施例奈米碳f長線通電流加熱溶 啤"的7F意圖。 斷的=係本技術方案實施例奈米線通電流加熱溶 射小圖/係、本技術方案實施例獲得的奈米碳管長線的場發 射大碥的拉曼光譜圖。 圖9係技術方案實施例的場發射電子源的電流-電壓 17 200921753 曲線示意圖。 【主要元件符號說明】 場發射電子源 10 奈米碳管長線 12 導電基體 14 奈米碳管長線第一端 122 奈米碳管長線第二端 124 場發射尖端 300 奈米碳管 302 真空室 50 1¾極接線柱 52 陰極接線柱 54 免點 56 18200921753 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a method for preparing a field emission electron source, and more particularly to a method for preparing a field emission electron source based on a carbon nanotube. [Prior Art] The field emission electron source operates at low temperature or room temperature, and has the advantages of low energy consumption, fast response speed, and low discharge compared with the heat emission electron source in the electric vacuum device, so the field emission electron source is used instead of the electricity. The source of thermal emission electrons in vacuum devices has become a hot topic of research. Carbon Nanotube (CNT) is a new carbon material discovered by Japanese researcher Iijima in 1991. See "Helical Microtubules of Graphitic Carbon", S. Iijima, Nature, vol.354, p56 (1991) ). The carbon nanotubes have excellent electrical conductivity, good chemical stability and large aspect ratio, and have a tip surface area close to the theoretical limit (the smaller the tip surface area, the more concentrated the local electric field), so the nanocarbon The field of field emission of vacuum electron sources has potential applications. Current research shows that one of the best field emission materials known for the carbon nanotube system, its tip size is only a few nanometers to tens of nanometers, with very low field emission voltage (less than 100 volts). It transmits extremely large current density, and its current is extremely stable and has a long service life. Therefore, it is very suitable as an excellent point electron source for electronic applications such as Scanning Electron Microscope and Transmission Electron Microscope. In the launching part. The prior carbon nanotube field emission electron source generally includes at least a conductive substrate and a carbon nanotube as a emitting end, and the carbon nanotube is formed on the conductive substrate 200921753:. At present, the method for forming a carbon tube on a conductive substrate mainly includes a method and an in situ growth method. Among them, the mechanical method is to fix the nano-junior tube to the conductive substrate by means of atomic force, a brother or electron microscope #, and the early root cannula, such a $half method is private, but Since the size of a single Nymphalil is too small, the operation is not easy and the efficiency is low. In addition, the field emission current of the carbon nanotube field emission electron source obtained by the method is small. In order to overcome the shortcomings of the small field flow and complicated operation of the nanocarbon field emission electron source assembled by the above mechanical method. The prior art provides a method of '= position growth'. The method firstly deposits a metal-catalyzed η on a conductive substrate and then directly grows a plurality of layers on the conductive substrate by chemical vapor deposition, electric solitary discharge or clock-evaporation. Nano carbon tube as a field emission two:,;: Although the method is simple to operate 'nano carbon tube and conductive substrate; good connection. However, the nano tube obstructs the ability to bond with the conductive substrate, and the carbon nanotubes are easily detached or pulled out by the electric field during use, thereby causing damage to the field electron source. Moreover, since the method cannot control the direction of the carbon nanotubes, there is still a problem of low efficiency and poor controllability. In addition, there is an electric field screen between the plurality of carbon nanotubes in the electron source structure. Efficiency - When working, only a small number of carbon nanotubes emit electrons, and it is not effective to increase the current density of the field emission electron source. .../ There is a cloud here, and it is necessary to provide a method for preparing a field emission electron source having a large field emission current. SUMMARY OF THE INVENTION A field emission electron source includes a conductive substrate and a carbon nanotube long line. The carbon nanotube long wire has a first end and a first end and a second end; 7 200921753 one end, the first end of the carbon nanotube long line is electrically connected to the conductive substrate, the nano carbon = the second long line The end extends outwardly from the electrically conductive substrate, the second end of the long section of the carbon nanotube comprising a plurality of protruding field emission tips. A method for preparing a field emission electron source, comprising the steps of: providing a carbon nanotube array formed on a "substrate" using a stretching tool ϋ nano ί! array to obtain a carbon nanotube to obtain - nanometer The carbon nanotube film or the non-rice stone is treated by using an organic solvent or applying a mechanical external force to treat the nanometer, the membrane or the carbon nanotube wire to obtain a long carbon nanotube line; and the nano stone is heated by a long line current A plurality of field emission tips are formed at the dissolution point; and a field emission electron source is obtained by arranging the long carbon nanotubes after the severing. The soil has a ΐί! technology comparison, the field emission electron source and its preparation method have its -, using the long carbon nanotube line as the field emission electron, ^: 2 official line includes a plurality of prominent field emission tips, The prepared-d-electron source has a large field emission current; the second: =:!, the tip, effectively reducing the field; the fall::, the effect; the third, the long-term carbon nanotube is a macro device, Early, therefore, the preparation of the field emission electron source provides the preparation efficiency of the field emission electron source. [Embodiment] Hereinafter, a detailed description will be given with reference to the accompanying drawings, and a method for preparing the same. Referring to FIG. 1 , a source 10 of the embodiment of the present technical solution includes a conductive substrate 14 and a ^ ^ ^ emission electron non-mudstone anti-official long line 12. The 200921753 nano tube long line 12 Having a first end 122 and a second end 124 opposite the first end ι 22, the first end ι 22 of the long carbon nanotube long line 12 is electrically connected to the conductive substrate 14, the second end of the long carbon tube 12 Extending outward from the conductive substrate 14 as an electron-emitting end. Further, the carbon nanotube long-line 12 is a bundle structure composed of a plurality of parallel end-to-end connected carbon nanotube bundles or a plurality of end-to-end nai A stranded wire structure consisting of a bundle of carbon nanotubes, the adjacent carbon nanotube bundles being tightly coupled by a van der Waals force, the bundle of carbon nanotubes comprising a plurality of carbon nanotubes connected end to end and oriented. The length of the long tube of the carbon tube is from 0.1 m to 1 mm, and the diameter is from 丄 micron to 1 〇〇. The second end 124 of the long carbon tube 12 is conical, and the diameter of the bean is away from the conductive. The direction of the base 14 is gradually reduced. See Figure 2Ϊ The second end 124 of the carbon nanotube long wire 12 includes a plurality of protruding field emission tips 300. The field emission tip 300 includes a plurality of substantially parallel TU tubes 'the plurality of carbon nanotubes are closely coupled by Van der Waals force The said field emission tip is conical-shaped. The top of the field emission tip is covered with a carbon nanotube 302. The carbon nanotube is Π)~Nano carbon tube 3〇2 The diameter of the tip is less than 5 nm. The carbon nanotube long line 12 _ of the rice & ” T扪 不木石厌& is early wall, double wall or multi-walled na:::. The carbon nanotube long line 12, the top end of the field emission tip, is tightly coupled, so that the heat of the field at the beginning of the field can be effectively transmitted and can be strongly influenced by the electric field force. 200921753 Please refer to item 3. From the photomicrograph of the carbon nanotubes, you can see the 卞 7 卞 射 射 射 射 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 〜 电子 电子 电子 电子 电子 电子 电子 电子 电子 电子 电子From the transmission electron microscopy of the long carbon nanotubes of the carbon nanotubes, "" at the transmitting end 5, it can be seen that the field emission in the long carbon tube 12 of the carbon nanotubes has a small number of walls and finer The ancient "^ anti-s has a more straight position, the number of walls is less than 5 layers, generally 2 or 3 layers, and its diameter is usually ^ ^ 〆 too half stone mountain " < hanging J in 5 Nai. The super-aligned row: the carbon nanotubes of the reverse 5 train have more than 5 layers and the diameter is about 15 nm. The conductive substrate 14 is made of a conductive material such as nickel, copper, tungsten or gold. , the molybdenum ^, etc. The conductive substrate 14 can be designed into other shapes according to actual needs, the shape of the crucible, the small column or the truncated cone shape. The conductive substrate 14 can also be opened on an insulating substrate. The conductive film. It can be understood that the first end 122 of the long carbon wire 12 of the carbon nanotube can be electrically connected to the conductive substrate 14 through a conductive paste. The manner of connection can also be achieved by intermolecular force or other means. The position of the long distance between the carbon nanotube and the conductive substrate 14 is not limited to ensure that the first end 122 of the long carbon nanotube 12 is The conductive substrate 14 can be electrically connected. For example, the angle between the long carbon wire 12 of the nano carbon tube and the conductive substrate 14 is an acute angle, the angle between the nanowire reverse length line 12 and the conductive substrate 14 is a right angle or the long line of the carbon nanotube tube 12 and the conductive substrate. The axial directions of 14 are parallel to each other. In this embodiment, since the long carbon nanotube line is used as the field emission electron source', the long carbon nanotube line includes a plurality of protruding field emission tips, and the prepared field emission electron source has a comparative Large field emission current; moreover, 200921753 The carbon nanotube long-term includes a plurality of field emission tips, and the field can shield the electron source from the electric field shielding effect. Effectively reduce the emission ϊ:·=5' provided by the embodiment of the technical solution The method for preparing the above-mentioned field laser electron source ίο, specifically includes the following steps: Step providing - a carbon nanotube array is formed on the substrate, preferably, the array is a super-sequential carbon nanotube array. The preparation method of the carbon nanotube array adopts a chemical gas deposition method, and the specific steps thereof include: (a) providing a flat substrate, which may be selected from a P-type or N-type germanium substrate, or a germanium substrate formed with an oxide layer. Preferably, the present embodiment adopts a 4-inch germanium substrate; (b) uniformly forms a catalyst layer on the surface of the substrate, and the catalyst layer material may be selected from iron (Fe), cobalt (c), nickel (Ni) or any combination thereof. (c) The above-mentioned substrate on which the catalyst layer is formed is annealed in 70 (TC to 90 (TC air for about 30 minutes to 9 G minutes; (d) the treated substrate is placed in a reaction furnace at The gas is heated to 5 〇〇 art to 74 〇 in a protective atmosphere, and then passed through a stone anti-source gas for about 5 minutes to 30 minutes to grow to obtain a carbon nanotube array having a degree greater than 100 μm. The carbon nanotube array is a series of pure carbon nanotubes formed by a plurality of carbon nanotubes that are parallel to each other and perpendicular to the substrate. The carbon nanotube array is substantially the same area as the above substrate. By controlling the growth conditions as described above, the super-aligned carbon nanotube array contains substantially no impurities such as amorphous carbon or residual catalyst metal particles. In this embodiment, the carbon source gas may be a chemically active hydrocarbon such as acetylene, ethylene or decane. The preferred carbon source gas in this embodiment is a fast gas. The shielding gas is helium or an inert gas. Preferred protection 11 200921753 The gas is argon. It can be understood that the carbon nanotube array provided by the present embodiment is not limited to the above preparation method. The carbon nanotube array provided in this embodiment is one of a single-walled carbon nanotube array, a double-walled carbon nanotube array, and a multi-walled carbon nanotube array. Step 2: Using a stretching tool to pull the carbon nanotube from the carbon nanotube array to obtain a carbon nanotube film or a carbon nanotube wire. The preparation of the nano-tetra (4) film or the carbon nanotube wire specifically includes the following: (a) selecting a plurality of carbon nanotube segments of a certain width from the carbon nanotube array, and the embodiment preferably has a certain The width of the tape contacts the carbon nanotube array to select a plurality of carbon nanotube bundles of a certain width, and (b) stretches the plurality of carbon nanotube bundles at a rate substantially perpendicular to the growth direction of the carbon nanotube array to form - continuous carbon nanotube film or nano carbon tube wire. During the above stretching process, the plurality of carbon nanotube bundles are subjected to a tensile force (the gradual separation from the substrate in the direction of stretching, and the selected plurality of carbon nanotube bundles respectively with the other nanometers due to the effect of the van der Waals force) The carbon tube bundle is pulled out end to end to form a "nanocarbon tube film or a nano carbon tube wire. The carbon nanotube film or the nano carbon tube wire comprises a plurality of end-to-end and aligned nanoparticles. Carboniferous pipe I. The naiwu carbon pipe film, the arrangement direction of the carbon nanotubes in the nanowires is basically parallel to the stretching direction of the nano-stone or the carbon nanotubes. Step 3, by using organic Solvent or mechanical external force treatment of the carbon nanotube film or nano carbon tube wire to obtain a nano carbon tube long line 12 200921753 The carbon nanotube film or the carbon nanotube wire prepared in the step described above can be treated with an organic solvent The carbon nanotube long line 12 is obtained. The specific treatment process includes: dropping the organic solvent into the carbon nanotube film through the test tube = infiltrating the entire surface of the tube, or infiltrating the carbon filament. Solution, the whole tube can also be immersed in a container containing a right 嫱~卞ΙΑΛ-, :3c not a stone counter-agent. The organic solvent is a gas-like X-agent "such as ethanol, methanol, acetone, two Ethyl chloride is preferably used in the embodiment of the present invention. The nanocarbon == after the organic solvent is impregnated, the surface tension of the volatile organic solvent is 1 _u., the non-meterite anti-tubular film Or carbon nanotubes: flat:: carbon nanotube fragments will be partially integrated into the carbon nanotubes (four) ^ carbon tube film or nano carbon tube surface volume ratio is small, reasonable, and has good mechanical strength and Resilience, view of the field. Money or nano carbon tube wire is conveniently used in the macro carbon tube film prepared in the first step of the 斤 太 太 太 太 太 太 太 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供 供Carbon tube long line 12. Lifting the tail of the shaft;::: sticking the spinning shaft of the carbon nanotube array. After the spinning ==:::: column is combined, the carbon nanotubes begin to wrap around the carbon tube array. Square: "Axis: Rotate out and move away from nanometer ^11. At this time, the carbon nanotube array is relative to the 0 π stretches her dimension to start, and Fang Cheng's other carbon nanotubes can wrap around the fiber and increase the length of the fiber. It can be understood that the above-mentioned = 13 200921753 is not limited in rotation, and can be reversed or reversed. Combination of phase inversion. Inversion 'or forward rotation and. It can be understood that it can also be obtained by directly pulling the carbon nanotubes in the stretched carbon tube array to obtain - too, ; = - nano step 4: the naval ship Line 12 pass =?,. Margin breaks form multiple field emission tips. Heart heating is stunned, and this step can be carried out in a vacuum environment, which specifically includes the following steps: Under the condition of the body protection!·" First, please refer to Fig. 6 and Fig. 7 to set up in a vacuum chamber 5 或 or to continue the reaction chamber which is not suspended by the official line 12 and is filled with gas. The true work to 5 〇 includes - ΈΓ iE iE ^ / r-* yang 妓 " (not shown) and - 知 pole 50 and a cathode terminal ίο·1 Pa, preferably 2xl (r5 Pa 0, the working degree is lower than lx and the anode terminal 52 and the dangerous pole wiring: J long line 12 two paste ^ _ θ and the cathode terminal ^ electrical connection. In this embodiment 'object pole terminal 52 and cathode The terminal 5 volt v ^ is not the length of the long line 12 is 25 micrometers long and the length is 2 centimeters. I fork is not Ζ The filling of the reaction chamber structure of the raw gas is the same as the vacuum chamber 5 ,, the inert gas can be 氦Gas, argon, etc. /, a voltage is applied across the carbon nanotube long line 12, and a current is applied to heat the sever. A 40 volt DC voltage is applied between the anode terminal 52 and the cathode terminal 54. It will be understood by those skilled in the art that the voltage applied between the anode terminal 52 and the cathode terminal 54 is the same as that of the selected carbon nanotube length 14 200921753. In the DC condition τ is heated by Joule heat. Carbon official long line 12. Heating temperature is preferably 2〇〇〇〖to 24〇〇κ, heating^ less than 1 hour In the vacuum DC heating process, the current through the long line 12 of the carbon nanotubes is combined;: Bu 4 .., Β B gradually rises, but the current begins to drop until the long carbon 12 of the carbon nanotubes is dissolved. Before the dissolution, the long line of the carbon nanotubes = a bright spot 56 will appear, and the long carbon tube 12 of the carbon nanotubes will be dissolved from the bright spot 56. ^ The resistance of each point in the long line 12 of the carbon carbon is different, so that the points are The voltage is also different. In the long line of the carbon nanotube long line 12, a larger voltage is obtained, which has a larger heating power, and more Joule heat is generated, so that the temperature of the point rises rapidly. High. During the process of dissolution, the resistance at this point will become larger and larger, resulting in a larger and higher partial voltage at the point. 'The same 4' temperature is also getting larger and larger until the point breaks, forming two electron emission. At the moment of melting, there will be a very small gap between the cathode and the anode, and at the same time near the position of the melting point, due to the fact that the carbon strip is 'poor vacuum', these factors will cause the moment of the material to be broken. Produces gas ionization. Ionized ion bombarded blown carbon nanotubes The end portion of the long wire 12 and a plurality of field emission tips are formed at the end portion. The vacuum melting method used in the embodiment avoids the dyeing of the fuse of the long carbon wire 12 of the carbon nanotube, and the nanometer during heating The mechanical strength of the long line η of the carbon tube will be improved to 'enable it has excellent field emission performance. Step 5: The long carbon wire 12 of the carbon nanotube is placed on the conductive substrate 14 to obtain the field emission electron source. The blown carbon nanotube long wire 12 is adhered to a 15 200921753 conductive substrate 14 through a conductive adhesive to obtain an electron emission source ι〇. The X-solution 4 can have an electron emission. The end carbon nanotubes • the long wires 12 are disposed on a conductive substrate 14 to obtain a field emission electron source having a plurality of electron emission ends. In the present embodiment, since the long carbon wire 12 of the carbon nanotube is a macroscopic device, it can be easily adhered to the conductive substrate 14, and the operation is simple. Therefore, the preparation method of the field emission electron source is simple, and the field can be improved. The efficiency of preparation of the emission electron source. : Referring to Fig. 8, the field emission tip of the long carbon nanotube 12 is _ stone "j ° day map ° analysis by the tearing spectrum shows that the defect peak of the field emission tip of the heat treated nanowire 12 is significantly reduced, The defect peak of Z = is lower. That is to say, the quality of the 23 carbon nanotubes in the field of the long carbon 12 of the carbon nanotubes is greatly reduced during the dissolution process, and the =-^ aspect is due to the carbon nanotubes. After the heat treatment, the defects are reduced, and the graphite layer rich in defects is easily collapsed at a high temperature to form a higher quality graphite layer. a fruit > Read Figure 9 'Field emission performance test for the above field emission electron source The carbon nanotube long line 12 is subjected to a time-breaking treatment to form two, and the field emission performance test of the field (four) sub-source is measured by using the crucible as an anode, wherein the tungsten needle tip is opposite to the pointed emitter end. The tip of the crucible and the long-term emitter of the carbon nanotube are at a distance of 100 μm. The two electrons formed by the vacuum severing are the T-T for the field emission current above the micro-ampere. The electron emission end has a diameter of about 5 microns, 16 200921753 The density of the field emission current is greater than 700 A/cm 2 . As described above, the present invention has indeed met the requirements of the invention patent, and the patent application is filed according to law. However, the above description is only a preferred embodiment of the present invention. The invention does not 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 included in the scope of the following patent application. The schematic diagram of the structure of the field emission electron source of the embodiment of the present invention is shown in FIG. 2 is an enlarged view of the electron emission end 2 of the long line of the carbon nanotube tube in FIG. 1 is a long line of the carbon nanotube tube obtained by the embodiment of the present technical solution. Scanning electron micrograph of the electron hair end. Fig. 4 is a transmission electron micrograph of the field hair and tip of the long carbon nanotube obtained in the embodiment of the present technical solution. ^ Preparation method of the field emission electron source of the embodiment of the present technical solution The schematic diagram of Fig. 2 is the 7F intention of the nano carbon f long-line current-heating dissolved beer in the embodiment of the technical solution. The broken method is the embodiment of the present invention. A small-graph/system, a Raman spectrum of a field emission ytterbium of a long line of carbon nanotubes obtained by an embodiment of the present technical solution. Fig. 9 is a schematic diagram of a current-voltage 17 of a field emission electron source of an embodiment of the technical solution. [Main component symbol description] Field emission electron source 10 Nano carbon tube long line 12 Conductive substrate 14 Nano carbon tube long line first end 122 Nano carbon tube long line Second end 124 Field emission tip 300 Carbon tube 302 Vacuum chamber 50 13⁄4 pole terminal 52 cathode terminal 54 free point 56 18