201001484 九、發明說明： 【發明所屬之技術領域】 本發明涉及一種場發射體及其製備方法，尤其涉及 一種基于奈米碳管的場發射體及其製備方法。 【先前技術】 奈米碳管係一種新型碳材料，其由日本研究人員飯島 澄男（s. 1中!^)在w91年首先發現，可參見“Heiicai Microtubules of Graphitic Carbon5% S. Iijima, Naturej Vol’354，56-58(1991)。奈米碳管具有極優異的導電性能， 且其具有幾乎接近理論極限的尖端表面積，而尖端表面積 愈小，其局部電場愈集十，所以奈米碳管係已知的最好的 場發射材料之一。奈米碳管具有極低的場發射電壓（小於 100伏特），可傳輸極大的電流密度，且電流穩定性較佳， 因而較適合做場發射顯示器件的發射材料。 奈米碳管場發射體一般包括一陰極基底及形成在陰極 基底上的作爲發射材料的奈米碳管層。奈米碳管場發射體 可應用在場發射平面顯示、真空電子源等領域。先前技術 中’通常使用的奈米碳管場發射體的製備方法包括直接生 長法及後續加工處理法兩種。 直接生長法通常係指：首先提供一陰極基底，在該陰 極基底表面形成一催化劑層；然後採用化學氣相沈積法在 該陰極基底的催化劑位置生長出奈米碳管以直接形成一奈 米碳管場發射體（請參見“ Low-temperature CVD growth of carbon nanotubes for field emission applicationM ， 201001484201001484 IX. Description of the Invention: [Technical Field] The present invention relates to a field emitter and a method of fabricating the same, and more particularly to a field emitter based on a carbon nanotube and a method of preparing the same. [Prior Art] Nano carbon tube is a new type of carbon material, which was first discovered by Japanese researcher Iijima Chengo (s. 1 in !^) in w91. See Heiicai Microtubules of Graphitic Carbon 5% S. Iijima, Naturej Vol '354, 56-58 (1991). The carbon nanotubes have excellent electrical conductivity and have a tip surface area close to the theoretical limit, and the smaller the tip surface area, the more the local electric field is, the carbon nanotubes. It is one of the best known field emission materials. The carbon nanotube has a very low field emission voltage (less than 100 volts), can transmit a large current density, and has better current stability, so it is more suitable for field emission. The emissive material of the display device. The carbon nanotube field emitter generally comprises a cathode substrate and a carbon nanotube layer as an emissive material formed on the cathode substrate. The carbon nanotube field emitter can be applied to the field emission plane display, Fields such as vacuum electron sources. In the prior art, the commonly used methods for preparing nanocarbon tube field emitters include direct growth method and subsequent processing methods. Direct growth method usually Refers to: firstly providing a cathode substrate, forming a catalyst layer on the surface of the cathode substrate; then growing a carbon nanotube at the catalyst site of the cathode substrate by chemical vapor deposition to directly form a carbon nanotube field emitter ( See "Low-temperature CVD growth of carbon nanotubes for field emission applicationM , 201001484
Kuang-chung Chen，Diamond & Related Materials，ν〇1·16， P566 ( 2007))。然，由於化學氣相沈積法生長的奈米碳管 陣列頂部表面有奈米碳管纏繞，因此，奈米碳管在該表面 的形態雜亂無章’這種情况導致該種奈米碳管場發射體的 場發射均勻性較差，且由於奈米碳管陣列中的奈米碳管的 排列密度較高，相鄰的奈米碳管之間存在著較强的電磁屏 蔽效應，影響了這種場發射體的場發射電流及其實際應用 性能。 〜 後續加工處理法通常係指··首先將已製備好的作爲發 射體的奈米碳管混合在漿料中；然後將上述漿料印刷在陰 極基底上以在該陰極基底上形成—場發射層，進而獲得一 奈米碳管場發射體。然，用㈣㈣ =密度較小’進而導致有效發射體的密度 ===取Γ採用印刷法製備的奈米碳管場發 差。切e取向雜亂無序，使得其場發射均勾性較 實為必碳管場發射體及其製備方法 句性和較大的場發：電：：：發射體具有較佳的場發射均 【發明内容】 u且實際應用性能好。 -種場發射體’其包括 片斷，該奈米碳管陣列片斷包括=體及一奈米碳管陣列 的第二端，該奈米碳管陣一端及與第-端相對 接’其中，該奈米唆管陣列片端與導電基體電連 、第一端包括多個場發射 201001484 尖端，該場發射尖端包括多個並列設置的奈米碳管。 ~發射體的製備方法，其包括以下步驟：製備-.奈米叙官陣列形成於—基底；提供一第—電極及一第二電 f "亥第電極和第二電極絕緣間隔設置；從該奈米碳管 列中取下-部分，將取下的該部分奈米碳管陣列的兩端 ^固定於第-電極與第二電極上’該部分奈米碳管陣列 2的奈米碳管從所述第—電極向第二電極延伸；以及在第 二電，和第二電極之間施加7_10伏的電壓，將該部分奈求 石厌官陣列熔斷，形成兩個相對的場發射體。 相較於先前技術，本技術方案實施例所提供的場發射 製備方法具有以下優點：其-，由於該發射體中的 :2 = B陣列片斷係經奈米碳管陣列直接熔斷獲得，該奈 米石厌官陣列熔斷處的端面整齊，即場發射體的場發射尖端 的端面签齊’因此’該發射體可實現均句的電子發射，進 而使其具有較佳的場發射均勻性；其二，由於該場發射尖 端包括多個並列的奈米碳管，因此場發射尖端頂部的距離 大於奈米碳管陣列中奈米碳管之間的距離’即電子發射端 之間的距離較大，因此，電子發射端之間的電場屏蔽效應 因此’該場發射體的場發射電流較大，實際應錄 月&較好。 【實施方式】 以下將結合附圖詳細說明本技術方案實施例 射體及其製備方法。 請-並參關ί、圖2及圖3,本技術方案實施例提供 201001484 一種場發射體10’其包括一導電基體14和一奈米碳管陣 列片斷16,所述的奈米碳管陣列片斷16包括一第一端162 及與第一端162相對的第二端164，第一端162與導電基 體電連接，第二端164包括多個場發射尖端166。 所述奈米碳管陣列片斷16包括多個長度基本相同的 奈米碳管168。奈米碳管陣列片斷16中的奈米碳管ι68在 奈米碳管陣列片斷16的第一端162相互平行排列且均勻分 布’維持奈米碳管陣列的形態。在奈米碳管陣列片斷16 的第二端164，奈米碳管168聚集形成多個奈米碳管束， 該奈米碳管束均勻分布，形成多個場發射尖端166。奈米 碳管陣列片斷16中的奈米碳管168在場發射尖端166中通 過凡德瓦爾力相互結合且並列設置。場發射尖端166的直 徑沿遠離導電基體14的方向逐漸减小，形成一 v型尖端。 場發射尖端的頂部爲電子發射端。奈米碳管陣列片斷 中奈米碳管168包括單壁奈米碳管、雙壁奈米碳管、多壁 奈米碳管或其任意組合，優選地，奈米碳管168的直徑爲 0.5奈米-50奈米，長度爲1〇〇微米q毫米。奈米碳管陣列 片斷16中的奈米碳管168之間的距離爲0.1奈米-5奈米。 奈米碳管陣列片斷16的長度爲1G微米_2毫米，直徑爲2 微米:細微米’本實施例中，奈米碳管168爲直徑爲1奈 米的早壁奈米碳管，長度爲15〇微米。奈米碳管陣列片斷 16的長度爲150微米，直徑爲5〇微米。奈米碳管⑽之 ^的距離爲G·1奈米。奈米碳管陣列片斷16中的場發射尖 端166頂部之間的距離爲50奈米-500奈米，大於奈来碳 201001484 管168之間的距離。 始二導！基體14由導電材料製成，如銅'鶴、金'雜、 /二思、、且。的合金。該導電基體14可依實際需要設計 的形狀，如錐形、細小的柱形或者圓台形。該導電 :中，道，可爲表面形成有—導電薄膜的絕緣基底。本實施 古持太、，電基體14爲鑛有銘臈㈣片。導電基體14用於 支撐不米碳管陣列片斷16，同時，可以使奈米碳管陣列片 斷16方便的與外界電路連通。 該奈米碳管陣列片斷16的第一端162通過分子間力與 導電基體14電連接。可以理解，奈米碳㈣列片斷16的 第端162與導電基n 14之間也可通過導電膝或金屬絲焊 接的方式連接。該奈米碳管陣列片斷16與導電基體“之 間的位置關係不限，只需確保該奈米碳管陣列片斷的第 一端162與該導電基體14電連接即可。 應用時，將上述場發射體10設置於一定電壓所形成的 電場中，在電壓作用下，由於奈米碳管168具有較好的場 發射特性，且場發射體10包括多個場發射尖端166，故所 述場發射體10在較小的電壓下即能發射電子。本實施例 中’當電壓達到200伏左右時’場發射體10開始發射電子， 産生場發射電流，隨著電壓的增加，場發射電流增加，在 電壓爲275伏時，可産生1〇〇微安左右的電流。請參見圖 4 ’拉曼光譜分析表明場發射尖端166處的奈米碳管ι68 的缺陷峰比標準奈米碳管168的缺陷峰低。也就說，場發 射大k 166處的奈米碳管168的品質較高，即，其導電性 201001484 ，較好，機械强度大’使上述場發射體料有較好的實際 …用性能。請參見® 5，由於該發射體1G巾的奈米碳管陣 ’ J片斷16包括夕個場發射尖端166，場發射尖端⑽頂部 的距離大於奈求碳管陣列片斷16中奈米碳管168之間的距 離’即電子發射端之間的距離較大，因此，電子發射端之 間的電場屏蔽效應較弱，因此，該場發射體W的場發射電 流較大，場發射性能較好。 a請參見圖6及圖7,本技術方案實施例提供一種上述 場發射體10的製備方法，包括以下步驟： 步驟一、製備一奈米碳管陣列2〇形成於一基底22。 本實知例中，奈米碳管陣列2〇的製備方法不限，可採 用化學氣相沈積法、電裳氣相沈積法、電弧放電法等。本 實施例中，奈米碳管陣列2 〇的製備方法選用化學氣相沈積 法’其具體包括以下步驟： (一） 提供一基底22,該基底22可選用矽晶片或表 面&有、，層氧化矽的矽晶片，優選地，其表面平整度以小於 U米以使後續在該基底22表面上生長的奈米碳管陣列 2〇的根部基本位於同一平面。 (—)在基底22表面形成一催化劑層，該催化劑層的 厚度爲幾奈米到幾百奈米，其中催化劑材料可爲鐵（Fe)、 銘（C〇)、鎳（Ni)或其任意組合的合金。 (二） 將表面沈積有催化劑層的基底22在300-400t： 酿度條件下氧化退火處理5-15小時以在該基底22表面形 成奈米級催化劑顆粒。 11 201001484 (四） 將該表面形成有奈米級催化劑顆粒的基底22 .裝載於一反應爐中，在保護氣體環境下加熱至500〜700攝 氏度（°C)，其中，該保護氣體爲惰性氣體或氮氣。 (五） 向反應爐内通入碳源氣與載氣的混合氣體，在 基底22表面生長奈米碳管陣列，進而可獲得本實施例中的 奈米碳管陣列20。其中，碳源氣可選用乙炔、乙烯等；該 載氣可爲h性軋體或氮氣；碳源氣的流量爲標準立 方厘米每分鐘（standard Cubic以如咖如⑽⑷加e， sccm) ’載氣的流量爲200-500sccm。 本實施例中所製備的奈米碳管陣歹4 2〇包括單壁太来 奈米碳管、多壁奈米碳管、或其任意組合：奈 ^官^直徑爲G.5奈米_⑽奈米，長度均爲鳩微米_2 太、 施例中，優選地，該奈米碳管陣列20爲直;p爲 1奈Γ:壁奈来碳管形成的陣列，其長度爲微； -電=二和广第一電極28及-第二電㈣，該第 和第一電極30絕緣間隔設置。 «亥苐 電極28和第二雷；ts in丄*兹& 料可選擇爲銅、鎢、金 電材料製成，其材 M 2R ^ ，，目、鉑或ΙΤ〇玻璃等。該第一雷 極28和第二電極3〇的 只弟電 與苐二電極3〇爲 限。本實施例中第一電極28 之間的距離與上述奈和第二電極3。 陣列2 〇的長度。優選地，第1 m離小於奈米破管 的距離爲100微米4 5毫 一第一電極30之間 宅未’本實施例令，奈米碳管陣列 12 201001484 20的長度爲300微米，第一電極28與第二電極3〇之間的 距離爲270微米。 步驟三、從該奈米碳管陣列2〇中取下一部分，將取下 的該部分奈米碳管陣列20的兩端分別固定於第一電極28 與第一電極30上，該部分奈米碳管陣列2〇中的奈米碳管 從所述第一電極28向第二電極3〇延伸。 優選地，此步驟在顯微鏡下操作，以精確選取部分奈 米石厌管陣列20，並將該部分奈米碳管陣列2〇的兩端分別 與第一電極28和第二電極3〇電連接。上述取下部分奈米 碳管陣列20並將其與第一電極28和第二電極州電連接的 方法具體包括以下步驟： 首先提供直徑爲20奈米- loo奈米的金屬絲。該 金屬絲的材料可爲銅、銀、金或其任意組合的合金。 咖其次，將金屬絲一端靠近奈米碳管陣列20,選取一定 寬度的部分奈米碳管陣列2〇’將一定寬度的部分奈米碳管 陣列從基底22上取下。上述過程中，由於奈米碳管與 金屬絲之間存在較强的分子間力H奈米碳管黏㈣ 金屬絲上’緩慢移動金屬絲，便可將選取㈣分奈米碳管 陣列^足基底22上取下。所述選取的部分奈米碳管陣列 2〇的寬度爲2微米.微米’本實施例中，部分奈米碳管 陣列20的寬度爲50微米。 取後將上述選取的部分奈米碳管 固定於第一電極28盥第一雷托川μ 响刀⑺ 电不仏與弟一電極3〇上’並分別與第一電極 "一電極30電連接，使部分奈米碳管陣列2〇中間懸 13 201001484 空並處於拉伸狀態。由於部分奈米碳管陣列2〇本身具有— 定的黏性，因此可將部分奈米碳管陣列2〇的兩端分別直接 黏附於第一電極28和第二電極30上或者也可以通過導電 膠如銀膠將部分奈米碳管陣列2〇的兩端分別黏附於第— 電極28和第二電極30上。 步驟四、在第一電極28和第二電極30之間施加7_1〇 伏的電壓’將該部分奈米碳管陣列2〇熔斷，形成兩個相 的場發射體10。 將該部分奈米碳管陣列2〇熔斷的方法具體包括以 步驟： 首先，將第-電極28、第二電極30和與第一電極28 和第二電極30電連接的部分奈米碳管陣列2〇置於一反應 室内。該反應室内部壓强爲低於1χ1(Γΐ帕的真空狀態，: 實施例反應室的内部的真空度優選爲2χ1〇_5帕。或者該反 應室内部可充滿惰性氣體取代真空環境，如氦氣或氬 等’以免部分奈米碳管陣列2G在溶斷過程中因化引 起結構破壞。 1 其次’在第-電極28和第二電極3〇之間施加7】伏 的電壓，通入電流加熱熔斷部分奈 本技術領域人員應當明白，第一電極=。第_妹 30之間施加的電壓與部分奈米碳管陣列2〇的寬度和長产 :關2實施例中’部分奈米碳管陣列2〇的寬度爲5〇微 米’長度爲300微米’在第一電極28與第二電極扣之門 施加- 8.25伏的直流電壓。該部分奈米碳管陣列2〇在焦 14 201001484 •耳熱的作用下加熱到溫度Α 2000Κ^2棚κ，加熱時間小 1小時。在上述真空直流加熱過程中，通過部分奈米碳 .管陣列2 0的電流會逐漸上升，但很快電流就開始下降，直 到部分奈米碳管陣列20被炫斷。在溶斷前，部分奈米碳管 陣列20的溫度最高的位置會出現亮點，部分奈米竣管陣列 20從該党點處熔斷’形成兩個相對的奈米碳管陣列片斷 26,所述的多個奈米碳管片斷26在炼斷處形成多個均句分 =的奈米碳管束’該奈米碳管束即爲場發射尖端。奈米碳 與第一電極28或第二電極3〇連接處的奈米碳管 維持奈米碳管陣列的形態不變。場發射尖端的頂部之間的 距離爲5奈米_1〇〇奈米，即€子發射端 米-100奈米。 雕舄3不 本實施例採用的真空熔斷法在加熱過程中，由於太 碳管陣列20經過—真空退火的過程，因此，奈米碳〜= 2〇中的奈米碳管的機械强度會有一定提高，‘ 良的機械性能。 丹W足俊 有以施例所提供的場發射體及其製備方法具 有j下優點.其一，由於該發射體中的奈米碳管陣列片斷 係經奈米碳管陣列直接熔斷獲 的端面整齊，即場發射體的尸典私 卡反官陣列溶斷處 4 P麥發射體的场發射尖端的端面整 該發射體可實現均勻的電子發射，進而使其具有較佳的場 ::勾：’·其二’由於該場發射尖端包括多 2官’因此場發射尖端頂部的距離大於奈米碳 不米碳管之間的距離，即電子發射端之間的 15 201001484 此，電子發射端之間的電場屏蔽效應較弱，因此，該場發 射體的場發射電流較大，實際應用性能較好；1三，本實 施例採用的真空炫斷法可避免機械法切割奈米碳管陣列時 對端口的污染。 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， 自不能以此限制本案之申請專利範圍。舉凡習知本案技藝 #援依本《明之精神所作之等效修飾或變化，皆應涵 盍於以下申請專利範圍内。 【圖式簡單說明】 圖！係本技財案實_所提㈣場發㈣的結構示 思圖。 圖2:本技術方案實施例所提供的場發射體中奈米碳 吕陣列片斷的掃描電鏡照片。 ',、端方案實施例所提供的場發射體的場發射 大螭的知描電鏡照片。 射端技術方案實施例所提供的場發射體的電子發 射蝙的拉曼光譜圖。 圖5係本技術方案實施例所 雷厭伽厅^供的場發射體的場發射 電壓與％發射電流的關係圖。 圖6係本技術方案實施例 法的流程圖。 &供的場發射體的製備方 工 圖7係本技術方案實施例所 藝流程圖。 供的場發射體的製備 16 201001484 【主要元件符號說明】 場發射體 10 導電基體 14 奈米碳管陣列片斷 16, 26 第一端 162 第二端 164 場發射尖端 166 奈米碳管 168 奈米碳管陣列 20 基底 22 第一電極 28 第二電極 30 17Kuang-chung Chen, Diamond & Related Materials, ν〇1·16, P566 (2007)). However, since the top surface of the carbon nanotube array grown by chemical vapor deposition has a carbon nanotube entanglement, the shape of the carbon nanotube on the surface is disordered. This situation leads to the carbon nanotube field emitter. The field emission uniformity is poor, and because of the high density of the arrangement of the carbon nanotubes in the carbon nanotube array, there is a strong electromagnetic shielding effect between adjacent carbon nanotubes, which affects the field emission. The field emission current of the body and its practical application performance. ~ Subsequent processing generally refers to first mixing the prepared carbon nanotubes as emitters in the slurry; then printing the above paste on the cathode substrate to form a field emission on the cathode substrate The layer, in turn, obtains a carbon nanotube field emitter. However, using (4) (4) = less density 'and resulting in the density of the effective emitter === take the difference in the field of the carbon nanotubes prepared by the printing method. The e-direction is disorderly and disorderly, which makes the field emission uniformity more realistic than the carbon tube field emitter and its preparation method. Sentence and large field emission: Electricity::: The emitter has better field emission. SUMMARY OF THE INVENTION u and the actual application performance is good. a seed field emitter comprising a segment, the carbon nanotube array segment comprising a body and a second end of the array of carbon nanotubes, the carbon nanotube array being flanked at one end and opposite the first end The end of the nanotube array is electrically connected to the conductive substrate, the first end comprising a plurality of field emission 201001484 tips, the field emission tip comprising a plurality of carbon nanotubes arranged side by side. a method for preparing an emitter, comprising the steps of: preparing a nano-array array formed on a substrate; providing a first electrode and a second electrical f " a first electrode and a second electrode insulating spacing; The carbon nanotube column is removed from the portion, and the removed ends of the portion of the carbon nanotube array are fixed on the first electrode and the second electrode. The carbon carbon of the portion of the carbon nanotube array 2 a tube extending from the first electrode to the second electrode; and applying a voltage of 7-10 volts between the second electrode and the second electrode to fuse the portion of the electron beam to form two opposing field emitters . Compared with the prior art, the field emission preparation method provided by the embodiments of the present technical solution has the following advantages: - since the 2 = B array segment in the emitter is obtained by direct melting of the carbon nanotube array, the nai The end face of the fracturing array of the fused stone array is neat, that is, the end face of the field emission tip of the field emitter is marked 'so that the emitter can realize the electron emission of the uniform sentence, thereby making it have better field emission uniformity; Second, since the field emission tip includes a plurality of juxtaposed carbon nanotubes, the distance between the tops of the field emission tips is greater than the distance between the carbon nanotubes in the carbon nanotube arrays, that is, the distance between the electron emission ends is larger. Therefore, the electric field shielding effect between the electron-emitting terminals is therefore 'the field emission current of the field emitter is large, and it is better to record the moon & [Embodiment] Hereinafter, an embodiment of the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings. Please refer to and refer to FIG. 2 and FIG. 3. The embodiment of the present technical solution provides 201001484. A field emitter 10' includes a conductive substrate 14 and a carbon nanotube array segment 16, the carbon nanotube array. The segment 16 includes a first end 162 and a second end 164 opposite the first end 162. The first end 162 is electrically coupled to the conductive substrate and the second end 164 includes a plurality of field emission tips 166. The carbon nanotube array segment 16 includes a plurality of carbon nanotubes 168 having substantially the same length. The carbon nanotubes ι68 in the carbon nanotube array segment 16 are arranged in parallel with each other at the first end 162 of the carbon nanotube array segment 16 and uniformly distributed to maintain the morphology of the carbon nanotube array. At the second end 164 of the carbon nanotube array segment 16, the carbon nanotubes 168 are aggregated to form a plurality of carbon nanotube bundles that are evenly distributed to form a plurality of field emission tips 166. The carbon nanotubes 168 in the carbon nanotube array segment 16 are bonded to each other in the field emission tip 166 by van der Waals forces and arranged side by side. The diameter of the field emission tip 166 gradually decreases in a direction away from the conductive substrate 14, forming a v-shaped tip. The top of the field emission tip is the electron emitting end. The carbon nanotube 168 in the carbon nanotube array segment comprises a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube or any combination thereof. Preferably, the diameter of the carbon nanotube 168 is 0.5. Nano-50 nm, length 1 μm qmm. The distance between the carbon nanotubes 168 in the segment 16 of the carbon nanotube array is from 0.1 nm to 5 nm. The carbon nanotube array segment 16 has a length of 1 Gm 2 mm and a diameter of 2 μm: fine micron. In this embodiment, the carbon nanotube 168 is an early-walled carbon nanotube having a diameter of 1 nm, and the length is 15 〇 micron. The carbon nanotube array segment 16 has a length of 150 microns and a diameter of 5 microns. The distance of the carbon nanotube (10) is G·1 nm. The distance between the tops of the field emission tips 166 in the carbon nanotube array segment 16 is between 50 nm and 500 nm, which is greater than the distance between the Nylon carbon 201001484 tube 168. Start two guides! The base 14 is made of a conductive material such as copper 'crab, gold', or two. Alloy. The conductive substrate 14 can be shaped according to actual needs, such as a tapered shape, a small cylindrical shape or a truncated cone shape. The conductive: medium, track, may be an insulating substrate on the surface of which a conductive film is formed. This implementation is ancient, too, and the electric base 14 is a mine with a Ming (4) piece. The conductive substrate 14 is used to support the carbon nanotube array segments 16, and at the same time, the carbon nanotube array fragments 16 can be conveniently communicated with external circuits. The first end 162 of the carbon nanotube array segment 16 is electrically coupled to the conductive substrate 14 by intermolecular forces. It will be appreciated that the first end 162 of the nano carbon (four) column segment 16 and the conductive base n 14 may also be joined by conductive knee or wire bonding. The positional relationship between the carbon nanotube array segment 16 and the conductive substrate is not limited, and it is only necessary to ensure that the first end 162 of the carbon nanotube array segment is electrically connected to the conductive substrate 14. The field emitter 10 is disposed in an electric field formed by a certain voltage. Under the action of the voltage, since the carbon nanotube 168 has better field emission characteristics and the field emitter 10 includes a plurality of field emission tips 166, the field The emitter 10 can emit electrons at a small voltage. In the present embodiment, when the voltage reaches about 200 volts, the field emitter 10 starts to emit electrons, generating field emission current, and as the voltage increases, the field emission current increases. At a voltage of 275 volts, a current of about 1 〇〇 microamperes can be generated. See Figure 4 for 'Raman spectroscopy. The defect peak of the carbon nanotube ι68 at the field emission tip 166 is smaller than that of the standard carbon nanotube 168. The defect peak is low. That is to say, the quality of the carbon nanotube 168 at the field emission large k 166 is higher, that is, its conductivity 201001484, better, and the mechanical strength is large, so that the above field emission material has better quality. Actual... use performance. Please refer to ® 5, since the carbon nanotube array J segment 16 of the emitter 1G towel includes a field emission tip 166, the distance from the top of the field emission tip (10) is greater than between the carbon nanotubes 168 in the carbon nanotube array segment 16 The distance 'that is, the distance between the electron-emitting ends is large. Therefore, the electric field shielding effect between the electron-emitting ends is weak. Therefore, the field emission current of the field emitter W is large, and the field emission performance is good. Referring to FIG. 6 and FIG. 7 , an embodiment of the present technical solution provides a method for preparing the field emitter 10, which includes the following steps: Step 1: Prepare a carbon nanotube array 2 to be formed on a substrate 22. In this embodiment, The preparation method of the carbon nanotube array 2〇 is not limited, and the chemical vapor deposition method, the electric vapor deposition method, the arc discharge method, etc. may be employed. In this embodiment, the preparation method of the carbon nanotube array 2 〇 is selected. The chemical vapor deposition method specifically includes the following steps: (1) providing a substrate 22 which may be selected from a germanium wafer or a surface & enamel wafer having a layer of yttrium oxide, preferably having a surface flatness of less than U m to make the follow-up at the base The roots of the carbon nanotube array 2〇 grown on the surface of the bottom 22 are substantially in the same plane. (-) A catalyst layer is formed on the surface of the substrate 22, and the catalyst layer has a thickness of several nanometers to several hundred nanometers, wherein the catalyst material It may be an alloy of iron (Fe), Ming (C〇), nickel (Ni) or any combination thereof. (2) The substrate 22 on which the catalyst layer is deposited is oxidized and annealed at 300-400 t: 15 hours to form nano-sized catalyst particles on the surface of the substrate 22. 11 201001484 (4) The substrate 22 having the surface formed with nano-sized catalyst particles is loaded in a reaction furnace and heated to 500~ under a protective gas atmosphere. 700 degrees Celsius (° C.), wherein the shielding gas is an inert gas or nitrogen. (5) A carbon nanotube array 20 is grown on the surface of the substrate 22 by introducing a mixed gas of a carbon source gas and a carrier gas into the reactor to obtain a carbon nanotube array 20 in the present embodiment. Wherein, the carbon source gas may be selected from acetylene, ethylene, etc.; the carrier gas may be a h-rolled body or nitrogen; the flow rate of the carbon source gas is a standard cubic centimeter per minute (standard Cubic is like a coffee (10) (4) plus e, sccm) The flow rate of the gas is 200-500 sccm. The carbon nanotubes 歹4 2〇 prepared in this embodiment includes a single-walled teracarbon tube, a multi-walled carbon nanotube, or any combination thereof: the diameter of the nanometer is G.5 nm _ (10) nanometer, the length is 鸠micron_2 too, in the example, preferably, the carbon nanotube array 20 is straight; p is 1 nanometer: an array formed by a wall carbon nanotube, the length of which is micro; - electric = two and wide first electrodes 28 and - second electric (four), the first and first electrodes 30 are insulated from each other. «Hui 电极 electrode 28 and second ray; ts in 丄 * & & material can be selected from copper, tungsten, gold materials, its material M 2R ^ ,, mesh, platinum or bismuth glass. The first and second electrodes 28 and 3 are limited to the second electrode and the second electrode. The distance between the first electrodes 28 in this embodiment is the same as the above-described second and third electrodes 3. The length of the array 2 〇. Preferably, the first m is less than the distance of the nanotube from 100 micrometers to 45 millimeters. The first electrode 30 is between the first embodiment, and the length of the carbon nanotube array 12 201001484 20 is 300 micrometers. The distance between one electrode 28 and the second electrode 3A is 270 microns. Step 3: Remove a portion from the carbon nanotube array 2, and fix the two ends of the removed portion of the carbon nanotube array 20 to the first electrode 28 and the first electrode 30, respectively. The carbon nanotubes in the carbon tube array 2〇 extend from the first electrode 28 to the second electrode 3〇. Preferably, this step is operated under a microscope to precisely select a portion of the nano-stone array 20 and electrically connect the two ends of the portion of the carbon nanotube array 2 to the first electrode 28 and the second electrode 3, respectively. . The above method of removing a portion of the carbon nanotube array 20 and electrically connecting it to the first electrode 28 and the second electrode state specifically includes the following steps: First, a wire having a diameter of 20 nm-loom nanometer is provided. The material of the wire may be an alloy of copper, silver, gold or any combination thereof. Next, one end of the wire is placed close to the carbon nanotube array 20, and a portion of the carbon nanotube array 2' of a certain width is selected to remove a portion of the carbon nanotube array of a certain width from the substrate 22. In the above process, due to the strong intermolecular force between the carbon nanotubes and the wire, the carbon nanotubes (4) on the wire are 'slowly moving the wire, and the four (four) carbon nanotube arrays can be selected. The substrate 22 is removed. The selected partial carbon nanotube array 2 has a width of 2 μm. Micron. In this embodiment, a portion of the carbon nanotube array 20 has a width of 50 μm. After taking, the selected partial carbon nanotubes are fixed to the first electrode 28, the first Leitochuan μ knife (7) is electrically connected to the first electrode and the first electrode is separated from the first electrode " an electrode 30 Connected so that part of the carbon nanotube array 2 〇 intermediate suspension 13 201001484 is empty and stretched. Since a part of the carbon nanotube array 2 has a certain viscosity, the two ends of the partial carbon nanotube array 2 can be directly adhered to the first electrode 28 and the second electrode 30, respectively, or can also be electrically conductive. A glue such as silver glue adheres both ends of a portion of the carbon nanotube array 2 to the first electrode 28 and the second electrode 30, respectively. Step 4, applying a voltage of 7 〇 volts between the first electrode 28 and the second electrode 30 to fuse the partial carbon nanotube array 2 , to form a field emitter 10 of two phases. The method of fusing the portion of the carbon nanotube array 2〇 specifically includes the steps of: first, the first electrode 28, the second electrode 30, and a portion of the carbon nanotube array electrically connected to the first electrode 28 and the second electrode 30 2〇 placed in a reaction chamber. The pressure inside the reaction chamber is less than 1χ1 (the vacuum state of the Γΐpa: The vacuum inside the reaction chamber of the embodiment is preferably 2χ1〇_5 Pa. Or the inside of the reaction chamber can be filled with an inert gas instead of a vacuum environment, such as 氦Gas or argon, etc. 'to prevent partial carbon nanotube array 2G from causing structural damage during the dissolution process. 1 Next 'apply a voltage of 7 volts between the first electrode 28 and the second electrode 3〇, and the current is applied. Heating the fuse part, the person skilled in the art should understand that the first electrode = the voltage applied between the first sister 30 and the width and length of the partial carbon nanotube array 2 :: off 2 part of the nano carbon in the embodiment The tube array 2〇 has a width of 5 μm and a length of 300 μm. A DC voltage of - 8.25 V is applied to the gate of the first electrode 28 and the second electrode button. The portion of the carbon nanotube array 2 is at the focus 14 201001484 • Under the action of ear heat, it is heated to a temperature of Κ2000Κ^2 shed, and the heating time is 1 hour. During the above vacuum DC heating process, the current through the partial nanocarbon tube array 20 will gradually rise, but the current starts very quickly. Drop until part of the nanocarbon The array 20 is stunned. Before the dissolution, some of the highest temperature positions of the carbon nanotube array 20 will appear bright spots, and some of the nanotube arrays 20 are blown from the party point to form two opposing carbon nanotubes. Array segment 26, the plurality of carbon nanotube segments 26 form a plurality of carbon nanotube bundles with a uniform sentence = at the refining point. The carbon nanotube bundle is a field emission tip. The nanocarbon and the first electrode The carbon nanotubes at the junction of 28 or the second electrode 3〇 maintain the morphology of the carbon nanotube array unchanged. The distance between the tops of the field emission tips is 5 nm-1 〇〇 nanometer, that is, the emitter end M-100 nm. Engraving 3 is not used in the vacuum fusing method of this embodiment. During the heating process, since the carbon nanotube array 20 undergoes a vacuum annealing process, the carbon in the nano carbon ~= 2〇 The mechanical strength of the pipe will be improved, 'good mechanical properties. Dan W Foot has the advantage of the field emitter provided by the application and its preparation method. First, due to the nano carbon in the emitter The tube array segment is directly fused by the carbon nanotube array and the end face is neat, that is, the field emitter The corpse private card anti-official array dissolves the end face of the field emission tip of the 4 P wheat emitter. The emitter can achieve uniform electron emission, which in turn makes it have a better field:: hook: '·二二' Since the field emission tip includes more than 2 officials', the distance between the tops of the field emission tips is greater than the distance between the carbon carbon nanotubes, that is, 15 201001484 between the electron emission ends, and the electric field shielding effect between the electron emission ends It is weaker. Therefore, the field emission current of the field emitter is large, and the practical application performance is good. 13. The vacuum slashing method used in this embodiment can avoid the pollution of the port when the carbon nanotube array is mechanically cut. 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. All the equivalent modifications or changes made by the spirit of the Ming Dynasty should be within the scope of the following patent application. [Simple diagram of the diagram] Figure! This is the structure of the textbook (4). Fig. 2 is a scanning electron micrograph of a nanocarbon array fragment in a field emitter provided by an embodiment of the present technical solution. ',, the field emission of the field emitter provided by the embodiment of the end scheme. The Raman spectrum of the electron emission bat of the field emitter provided by the embodiment of the emitter technique. Fig. 5 is a graph showing the relationship between the field emission voltage and the % emission current of the field emitter provided by the embodiment of the present invention. Figure 6 is a flow chart of an embodiment of the present technical solution. The preparation method of the field emitter for the present invention is shown in the flowchart of the embodiment of the present technical solution. Preparation of field emitters 16 201001484 [Main component symbol description] Field emitter 10 Conductive substrate 14 Carbon nanotube array segment 16, 26 First end 162 Second end 164 Field emission tip 166 Carbon nanotube 168 nm Carbon tube array 20 substrate 22 first electrode 28 second electrode 30 17