TWI386971B - Field emitter and method for making the same - Google Patents
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本發明涉及一種場發射體及其製備方法，尤其涉及一種基於奈米碳管的場發射體及其製備方法。 The invention relates to a field emitter and a preparation method thereof, in particular to a field emitter based on a carbon nanotube and a preparation method thereof.
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.Iijima)在1991年首先發現，可參見“Helical Microtubules of Graphitic Carbon”,S.Iijima,Nature,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，其局部電場愈集中，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。 The carbon nanotubes are a new type of carbon material first discovered by Japanese researcher S. Iijima in 1991. See "Helical Microtubules of Graphitic Carbon", S.Iijima, Nature, 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 concentrated the local electric field, so the carbon nanotubes are the best known field emission materials. One. The carbon nanotube has a very low field emission voltage (less than 100 volts), can transmit a large current density, and has good current stability, and thus is suitable as a radiation material for a field emission display device.
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為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。 The carbon nanotube field emitter generally comprises a cathode substrate and a carbon nanotube layer as an emissive material formed on the cathode substrate. Nano carbon nanotube emitters can be used in fields such as field emission flat display, vacuum electron source, and the like. In the prior art, the commonly used method for preparing a carbon nanotube field emitter includes both a direct growth method and a subsequent processing method.
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 application”，Kuang-chung Chen，Diamond & Related Materials，Vol.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。 The direct growth method generally 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 nanocarbon Tube field emitter (see "Low-temperature CVD growth of carbon nanotubes for field" Emission application", Kuang-chung Chen, Diamond & Related Materials, Vol. 16, P566 (2007). However, since the top surface of the carbon nanotube array grown by chemical vapor deposition has a carbon nanotube winding, The shape of the carbon nanotubes on the surface is disordered, which leads to poor uniformity of field emission of the carbon nanotube field emitters, and because of the high density of 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 current of this field emitter and its practical application performance.
後續加工處理法通常係指：首先將已製備好的作為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一場發射層，進而獲得一奈米碳管場發射體。然，用印刷法形成的場發射層中奈米碳管的密度較小，進而導致有效發射體的密度較小，場發射電流較小；並且，由於採用印刷法製備的奈米碳管場發射體中的奈米碳管取向雜亂無序，使得其場發射均勻性較差。 Subsequent processing generally refers to: firstly preparing a prepared carbon nanotube as an emitter in a slurry; then printing the slurry on a cathode substrate to form a field emission layer on the cathode substrate, and further Obtain a nano carbon nanotube field emitter. However, the density of the carbon nanotubes in the field emission layer formed by the printing method is small, which results in a smaller density of the effective emitter and a smaller field emission current; and, due to the carbon nanotube field emission prepared by the printing method. The orientation of the carbon nanotubes in the body is disorderly and disorderly, which makes the field emission uniformity poor.
有鑒於此，提供一種奈米碳管場發射體及其製備方法實為必要，其可使奈米碳管場發射體具有較佳的場發射均勻性和較大的場發射電流且實際應用性能好。 In view of this, it is necessary to provide a carbon nanotube field emitter and a preparation method thereof, which can make the carbon nanotube field emitter have better field emission uniformity and large field emission current and practical application performance. it is good.
一種場發射體，其包括一導電基體及一奈米碳管陣列片斷，該奈米碳管陣列片斷包括一第一端及與第一端相對的第二端，該奈米碳管陣列片斷的第一端與導電基體電連接，其中，該奈米碳管陣列片斷的第二端包括多個場 發射尖端，該場發射尖端包括多個並列設置的奈米碳管，所述場發射尖端的直徑沿遠離導電基底的方向逐漸减小。 A field emitter comprising a conductive substrate and a carbon nanotube array segment, the carbon nanotube array segment comprising a first end and a second end opposite the first end, the carbon nanotube array segment The first end is electrically connected to the conductive substrate, wherein the second end of the carbon nanotube array segment comprises a plurality of fields An emission tip comprising a plurality of carbon nanotubes arranged side by side, the diameter of the field emission tip gradually decreasing in a direction away from the conductive substrate.
一種場發射體的製備方法，其包括以下步驟：製備一奈米碳管陣列形成於一基底；提供一第一電極及一第二電極，該第一電極和第二電極絕緣間隔設置；從該奈米碳管陣列中取下一部分，將取下的該部分奈米碳管陣列的兩端分別固定於第一電極與第二電極上，該部分奈米碳管陣列中的奈米碳管從所述第一電極向第二電極延伸；以及在第一電極和第二電極之間施加7-10伏的電壓，將該部分奈米碳管陣列熔斷，形成兩個相對的場發射體。 A method for preparing a field emitter, comprising the steps of: preparing a carbon nanotube array formed on a substrate; providing a first electrode and a second electrode, wherein the first electrode and the second electrode are insulated from each other; Removing a portion of the carbon nanotube array, and fixing the two ends of the removed portion of the carbon nanotube array to the first electrode and the second electrode, respectively, the carbon nanotubes in the portion of the carbon nanotube array The first electrode extends toward the second electrode; and a voltage of 7-10 volts is applied between the first electrode and the second electrode to fuse the portion of the carbon nanotube array to form two opposing field emitters.
相較於先前技術，本技術方案實施例所提供的場發射體及其製備方法具有以下優點：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得，該奈米碳管陣列熔斷處的端面整齊，即場發射體的場發射尖端的端面整齊，因此，該發射體可實現均勻的電子發射，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。 Compared with the prior art, the field emitter provided by the embodiments of the present technical solution and the preparation method thereof have the following advantages: First, since the carbon nanotube array segments in the emitter are directly fused through the carbon nanotube array, The end face of the carbon nanotube array fuse is neat, that is, the end face of the field emission tip of the field emitter is neat, and therefore, the emitter can achieve uniform electron emission, thereby providing 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 array, that is, the distance between the electron emission ends is larger. Therefore, the electric field shielding effect between the electron emitting ends is weak. Therefore, the field emission current of the field emitter is large, and the practical application performance is good.
以下將結合附圖詳細說明本技術方案實施例的場發射體及其製備方法。 Hereinafter, a field emitter of an embodiment of the present technical solution and a method of fabricating the same will be described in detail with reference to the accompanying drawings.
請一並參閱圖1、圖2及圖3，本技術方案實施例提供一種場發射體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。 Referring to FIG. 1 , FIG. 2 and FIG. 3 , the embodiment of the present invention provides a field emitter 10 including a conductive substrate 14 and a carbon nanotube array segment 16 , the carbon nanotube array 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.
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168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。場發射尖端的頂部為電子發射端。奈米碳管陣列片斷16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的直徑為0.5奈米-50奈米，長度為100微米-1毫米。奈米碳管陣列片斷16中的奈米碳管168之間的距離為0.1奈米-5奈米。奈米碳管陣列片斷16的長度為10微米-2毫米，直徑為2微米-200微米，本實施例中，奈米碳管168為直徑為1奈米的單壁奈米碳管，長度為150微米。奈米碳管陣列片斷16的長度為150微米，直徑為50微米。奈米碳管168之間的距離為0.1奈米。奈米碳管陣列片斷16中的場發射尖端166頂部之間的距離為50奈米-500奈米，大於奈米碳管168 之間的距離。 The carbon nanotube array segment 16 includes a plurality of carbon nanotubes 168 having substantially the same length. The carbon nanotubes 168 in the carbon nanotube array segment 16 are arranged parallel to each other at the first end 162 of the carbon nanotube array segment 16 and are evenly 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 tapers 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 16 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 nm - 50 nm, length 100 microns - 1 mm. The distance between the carbon nanotubes 168 in the carbon nanotube array segment 16 is from 0.1 nm to 5 nm. The carbon nanotube array segment 16 has a length of 10 micrometers to 2 millimeters and a diameter of 2 micrometers to 200 micrometers. In this embodiment, the carbon nanotube tubes 168 are single-walled carbon nanotubes having a diameter of 1 nanometer and the length is 150 microns. The carbon nanotube array segment 16 has a length of 150 microns and a diameter of 50 microns. The distance between the carbon nanotubes 168 is 0.1 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 carbon nanotubes 168. the distance between.
該導電基體14由導電材料製成，如銅、鎢、金、鉬、鉑或其任意組合的合金。該導電基體14可依實際需要設計成一定的形狀，如錐形、細小的柱形或者圓台形。該導電基體14也可為表面形成有一導電薄膜的絕緣基底。本實施例中，導電基體14為鍍有鋁膜的矽片。導電基體14用於支撑奈米碳管陣列片斷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。 The conductive substrate 14 is made of a conductive material such as an alloy of copper, tungsten, gold, molybdenum, platinum or any combination thereof. The conductive substrate 14 can be designed into a certain shape according to actual needs, such as a cone shape, a small column shape or a truncated cone shape. The conductive substrate 14 can also be an insulating substrate having a conductive film formed on its surface. In this embodiment, the conductive substrate 14 is a ruthenium plate coated with an aluminum film. The conductive substrate 14 is used to support the carbon nanotube array segments 16, and at the same time, the carbon nanotube array segments 16 can be conveniently communicated with external circuitry.
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，奈米碳管陣列片斷16的第一端162與導電基體14之間也可通過導電膠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14之間的位置關係不限，只需確保該奈米碳管陣列片斷16的第一端162與該導電基體14電連接即可。 The first end 162 of the carbon nanotube array segment 16 is electrically coupled to the conductive substrate 14 by intermolecular forces. It can be understood that the first end 162 of the carbon nanotube array segment 16 and the conductive substrate 14 can also be connected by conductive glue or wire bonding. The positional relationship between the carbon nanotube array segment 16 and the conductive substrate 14 is not limited, and it is only necessary to ensure that the first end 162 of the carbon nanotube array segment 16 is electrically connected to the conductive substrate 14.
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，產生場發射電流，隨著電壓的增加，場發射電流增加，在電壓為275伏時，可產生100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168的缺陷峰比標準奈米碳管168的缺陷峰低。也就說，場發射尖端166處的奈米碳管168的品質較高，即，其導電性能較好，機械强度大，使上述場發射體10具有較好的實 際應用性能。請參見圖5，由於該發射體10中的奈米碳管陣列片斷16包括多個場發射尖端166，場發射尖端166頂部的距離大於奈米碳管陣列片斷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10的場發射電流較大，場發射性能較好。 In application, the field emitter 10 is placed in an electric field formed by a certain voltage. Under the action of the voltage, the carbon nanotube 168 has better field emission characteristics, and the field emitter 10 includes a plurality of field emission tips 166. Therefore, the field emitter 10 can emit electrons at a small voltage. In this embodiment, when the voltage reaches about 200 volts, the field emitter 10 starts to emit electrons, and generates a field emission current. As the voltage increases, the field emission current increases, and when the voltage is 275 volts, about 100 microamperes can be generated. Current. Referring to FIG. 4, Raman spectroscopy analysis indicates that the defect peak of the carbon nanotube 168 at the field emission tip 166 is lower than the defect peak of the standard carbon nanotube 168. That is to say, the quality of the carbon nanotubes 168 at the field emission tip 166 is higher, that is, the conductivity is better and the mechanical strength is large, so that the field emitter 10 has a better quality. Application performance. Referring to FIG. 5, since the carbon nanotube array segment 16 in the emitter 10 includes a plurality of field emission tips 166, the distance from the top of the field emission tip 166 is greater than between the carbon nanotubes 168 in the segment 16 of the carbon nanotube array. The distance between the electron-emitting ends is large, and therefore, the electric field shielding effect between the electron-emitting ends is weak. Therefore, the field emission current of the field emitter 10 is large, and the field emission performance is good.
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： 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:
步驟一、製備一奈米碳管陣列20形成於一基底22。 Step 1. A carbon nanotube array 20 is prepared on a substrate 22.
本實施例中，奈米碳管陣列20的製備方法不限，可採用化學氣相沈積法、電漿氣相沈積法、電弧放電法等。本實施例中，奈米碳管陣列20的製備方法選用化學氣相沈積法，其具體包括以下步驟： In this embodiment, the preparation method of the carbon nanotube array 20 is not limited, and a chemical vapor deposition method, a plasma vapor deposition method, an arc discharge method, or the like may be employed. In this embodiment, the method for preparing the carbon nanotube array 20 is a chemical vapor deposition method, which specifically includes the following steps:
(一)提供一基底22，該基底22可選用矽晶片或表面有一層氧化矽的矽晶片，優選地，其表面平整度以小於1微米，以使後續在該基底22表面上生長的奈米碳管陣列20的根部基本位於同一平面。 (a) providing a substrate 22 which may be selected from a germanium wafer or a germanium wafer having a layer of yttria on the surface, preferably having a surface flatness of less than 1 micrometer to allow subsequent growth of the nanoparticle on the surface of the substrate 22. The roots of the carbon tube array 20 are substantially in the same plane.
(二)在基底22表面形成一催化劑層，該催化劑層的厚度為幾奈米到幾百奈米，其中催化劑材料可為鐵(Fe)、鈷(Co)、鎳(Ni)或其任意組合的合金。 (2) forming a catalyst layer on the surface of the substrate 22, the catalyst layer having a thickness of several nanometers to several hundred nanometers, wherein the catalyst material may be iron (Fe), cobalt (Co), nickel (Ni) or any combination thereof. Alloy.
(三)將表面沈積有催化劑層的基底22在300-400℃溫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。 (3) The substrate 22 having the catalyst layer deposited on the surface thereof is subjected to an oxidation annealing treatment at a temperature of 300 to 400 ° C for 5 to 15 hours to form nano-sized catalyst particles on the surface of the substrate 22 .
(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(℃)，其中，該保護氣體為惰性氣體或氮氣。 (4) The substrate 22 having the surface-formed catalyst particles formed thereon is placed in a reaction furnace and heated to 500 to 700 ° C (° C.) under a protective gas atmosphere, wherein the shielding gas is an inert gas or nitrogen.
(五)向反應爐內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；該載氣可為惰性氣體或氮氣；碳源氣的流量為20-50標準立方厘米每分鐘(Standard Cubic Centimeter per Minute,sccm)，載氣的流量為200-500sccm。 (5) A carbon monoxide array 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, and the carbon nanotube array 20 in the present embodiment can be obtained. Among them, the carbon source gas may be selected from acetylene, ethylene, etc.; the carrier gas may be an inert gas or nitrogen; the flow rate of the carbon source gas is 20-50 standard cubic centimeters per minute (Standard Cubic Centimeter per Minute, sccm), the flow rate of the carrier gas It is 200-500 sccm.
本實施例中所製備的奈米碳管陣列20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。奈米碳管的直徑為0.5奈米-100奈米，長度均為200微米-2毫米。本實施例中，優選地，該奈米碳管陣列20為直徑為1奈米的單壁奈米碳管形成的陣列，其長度為300微米。 The carbon nanotube array 20 prepared in this embodiment comprises a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, or any combination thereof. The carbon nanotubes have a diameter of 0.5 nm to 100 nm and a length of 200 μm to 2 mm. In this embodiment, preferably, the carbon nanotube array 20 is an array of single-walled carbon nanotubes having a diameter of 1 nm and having a length of 300 μm.
步驟二、提供一第一電極28及一第二電極30，該第一電極28和第二電極30絕緣間隔設置。 Step 2, a first electrode 28 and a second electrode 30 are provided. The first electrode 28 and the second electrode 30 are insulated and spaced apart.
該第一電極28和第二電極30由導電材料製成，其材料可選擇為銅、鎢、金、鉬、鉑或ITO玻璃等。該第一電極28和第二電極30的形狀不限。本實施例中第一電極28與第二電極30為銅片。所述第一電極28和第二電極30之間的距離與上述奈米碳管陣列20中奈米碳管的長度有關，第一電極28和第二電極30之間的距離小於奈米碳管陣列20的長度。優選地，第一電極28與第二電極30之間的距離為100微米-1.5毫米，本實施例中，奈米碳管陣列20的 長度為300微米，第一電極28與第二電極30之間的距離為270微米。 The first electrode 28 and the second electrode 30 are made of a conductive material, and the material thereof may be selected from copper, tungsten, gold, molybdenum, platinum or ITO glass. The shapes of the first electrode 28 and the second electrode 30 are not limited. In this embodiment, the first electrode 28 and the second electrode 30 are copper sheets. The distance between the first electrode 28 and the second electrode 30 is related to the length of the carbon nanotube in the carbon nanotube array 20, and the distance between the first electrode 28 and the second electrode 30 is smaller than that of the carbon nanotube. The length of the array 20. Preferably, the distance between the first electrode 28 and the second electrode 30 is 100 micrometers to 1.5 millimeters. In this embodiment, the carbon nanotube array 20 is The length is 300 microns and the distance between the first electrode 28 and the second electrode 30 is 270 microns.
步驟三、從該奈米碳管陣列20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與第二電極30上，該部分奈米碳管陣列20中的奈米碳管從所述第一電極28向第二電極30延伸。 Step 3: Remove a portion from the carbon nanotube array 20, and fix the two ends of the removed portion of the carbon nanotube array 20 to the first electrode 28 and the second electrode 30, respectively. The carbon nanotubes in the tube array 20 extend from the first electrode 28 toward the second electrode 30.
優選地，此步驟在顯微鏡下操作，以精確選取部分奈米碳管陣列20，並將該部分奈米碳管陣列20的兩端分別與第一電極28和第二電極30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30電連接的方法具體包括以下步驟： Preferably, this step is operated under a microscope to precisely select a portion of the carbon nanotube array 20 and electrically connect the two ends of the portion of the carbon nanotube array 20 to the first electrode 28 and the second electrode 30, respectively. The above method for removing a portion of the carbon nanotube array 20 and electrically connecting the same to the first electrode 28 and the second electrode 30 specifically includes the following steps:
首先，提供一直徑為20奈米-100奈米的金屬絲。該金屬絲的材料可為銅、銀、金或其任意組合的合金。 First, a wire having a diameter of 20 nm to 100 nm is provided. The material of the wire may be an alloy of copper, silver, gold or any combination thereof.
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20，將一定寬度的部分奈米碳管陣列20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，因此，奈米碳管黏附於金屬絲上，緩慢移動金屬絲，便可將選取的部分奈米碳管陣列20從基底22上取下。所述選取的部分奈米碳管陣列20的寬度為2微米-200微米，本實施例中，部分奈米碳管陣列20的寬度為50微米。 Next, one end of the wire is placed close to the carbon nanotube array 20, and a portion of the carbon nanotube array 20 of a certain width is selected to remove a portion of the carbon nanotube array 20 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 adhere to the wire and slowly move the wire to select a part of the carbon nanotube array. 20 is removed from the substrate 22. The selected partial carbon nanotube array 20 has a width of 2 micrometers to 200 micrometers. In this embodiment, a portion of the carbon nanotube array 20 has a width of 50 micrometers.
最後，將上述選取的部分奈米碳管陣列20的兩端分別固定於第一電極28與第二電極30上，並分別與第一電極28與第二電極30電連接，使部分奈米碳管陣列20中間懸空 並處於拉伸狀態。由於部分奈米碳管陣列20本身具有一定的黏性，因此可將部分奈米碳管陣列20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20的兩端分別黏附於第一電極28和第二電極30上。 Finally, the two ends of the selected partial carbon nanotube array 20 are respectively fixed on the first electrode 28 and the second electrode 30, and are electrically connected to the first electrode 28 and the second electrode 30, respectively, to make a portion of the nanocarbon. Tube array 20 is suspended in the middle And in a stretched state. Since some of the carbon nanotube arrays 20 themselves have a certain viscosity, the two ends of the partial carbon nanotube array 20 can be directly adhered to the first electrode 28 and the second electrode 30, respectively, or can also pass through a conductive adhesive such as silver. The glue adheres both ends of the partial carbon nanotube array 20 to the first electrode 28 and the second electrode 30, respectively.
步驟四、在第一電極28和第二電極30之間施加7-10伏的電壓，將該部分奈米碳管陣列20熔斷，形成兩個相對的場發射體10。 Step 4: Applying a voltage of 7-10 volts between the first electrode 28 and the second electrode 30, the partial carbon nanotube array 20 is fused to form two opposing field emitters 10.
將該部分奈米碳管陣列20熔斷的方法具體包括以下步驟： The method for melting the partial carbon nanotube array 20 specifically includes the following steps:
首先，將第一電極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20置於一反應室內。該反應室內部壓强為低於1×10-1帕的真空狀態，本實施例反應室的內部的真空度優選為2×10-5帕。或者該反應室內部可充滿惰性氣體取代真空環境，如氦氣或氬氣等，以免部分奈米碳管陣列20在熔斷過程中因為氧化而引起結構破壞。 First, the first electrode 28, the second electrode 30, and a portion of the carbon nanotube array 20 electrically connected to the first electrode 28 and the second electrode 30 are placed in a reaction chamber. The pressure inside the reaction chamber is in a vacuum state of less than 1 × 10 -1 Pa, and the degree of vacuum inside the reaction chamber of the present embodiment is preferably 2 × 10 -5 Pa. Alternatively, the inside of the reaction chamber may be filled with an inert gas instead of a vacuum environment such as helium or argon to prevent structural damage of the partial carbon nanotube array 20 due to oxidation during the fusing process.
其次，在第一電極28和第二電極30之間施加7-10伏的電壓，通入電流加熱熔斷部分奈米碳管陣列20。 Next, a voltage of 7-10 volts is applied between the first electrode 28 and the second electrode 30, and an electric current is applied to heat the portion of the carbon nanotube array 20.
本技術領域人員應當明白，第一電極28與第二電極30之間施加的電壓與部分奈米碳管陣列20的寬度和長度有關。本實施例中，部分奈米碳管陣列20的寬度為50微米，長度為300微米，在第一電極28與第二電極30之間施加一8.25伏的直流電壓。該部分奈米碳管陣列20在焦耳熱的 作用下加熱到溫度為2000K至2400K，加熱時間小於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20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被熔斷。在熔斷前，部分奈米碳管陣列20的溫度最高的位置會出現亮點，部分奈米碳管陣列20從該亮點處熔斷，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在熔斷處形成多個均勻分布的奈米碳管束，該奈米碳管束即為場發射尖端。奈米碳管片斷26與第一電極28或第二電極30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為5奈米-100奈米，即電子發射端之間的距離為5奈米-100奈米。 Those skilled in the art will appreciate that the voltage applied between the first electrode 28 and the second electrode 30 is related to the width and length of the portion of the nanotube array 20. In this embodiment, a portion of the nanotube array 20 has a width of 50 microns and a length of 300 microns, and a DC voltage of 8.25 volts is applied between the first electrode 28 and the second electrode 30. The portion of the carbon nanotube array 20 is in Joule heat It is heated to a temperature of 2000K to 2400K and a heating time of less than 1 hour. During the above vacuum DC heating process, the current through the partial carbon nanotube array 20 gradually rises, but the current begins to drop until the partial carbon nanotube array 20 is blown. Before the fusing, a portion of the highest temperature of the portion of the carbon nanotube array 20 will have a bright spot, and a portion of the carbon nanotube array 20 is blown from the bright spot to form two opposing carbon nanotube array segments 26, which are mostly The carbon nanotube segments 26 form a plurality of uniformly distributed carbon nanotube bundles at the fuse, the nanocarbon bundle being the field emission tip. The carbon nanotubes at the junction of the carbon nanotube segments 26 with the first electrode 28 or the second electrode 30 maintain the morphology of the carbon nanotube array unchanged. The distance between the tops of the field emission tips is 5 nm to 100 nm, that is, the distance between the electron emitting ends is 5 nm to 100 nm.
本實施例採用的真空熔斷法在加熱過程中，由於奈米碳管陣列20經過一真空退火的過程，因此，奈米碳管陣列20中的奈米碳管的機械强度會有一定提高，使之具備更優良的機械性能。 The vacuum fusing method used in the embodiment has a certain increase in the mechanical strength of the carbon nanotubes in the carbon nanotube array 20 due to a vacuum annealing process during the heating process. It has better mechanical properties.
本技術方案實施例所提供的場發射體及其製備方法具有以下優點：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得，該奈米碳管陣列熔斷處的端面整齊，即場發射體的場發射尖端的端面整齊，因此，該發射體可實現均勻的電子發射，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；其三，本實施例採用的真空熔斷法可避免機械法切割奈米碳管陣列時對端口的污染。 The field emitter provided by the embodiment of the present technical solution and the preparation method thereof have the following advantages: First, since the carbon nanotube array segment in the emitter is directly melted through the carbon nanotube array, the carbon nanotube is obtained. The end face of the array fuse is neat, that is, the end face of the field emission tip of the field emitter is neat, so that the emitter can achieve uniform electron emission, thereby making it have better field emission uniformity; second, due to the field emission The tip includes a plurality of juxtaposed carbon nanotubes, so the distance between the tops of the field emission tips is greater than the distance between the carbon nanotubes in the array of carbon nanotubes, that is, the distance between the electron-emitting ends is large, and therefore, the electron-emitting end The electric field shielding effect between It is weak. Therefore, the field emission current of the field emitter is large, and the practical application performance is good. Thirdly, the vacuum fuse method used in the embodiment can avoid the pollution of the port when the carbon nanotube array is mechanically cut.
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。舉凡習知本案技藝之人士援依本發明之精神所作之等效修飾或變化，皆應涵蓋於以下申請專利範圍內。 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 of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.
10‧‧‧場發射體 10‧‧‧ Field Emitter
14‧‧‧導電基體 14‧‧‧Electrical substrate
16,26‧‧‧奈米碳管陣列片斷 16,26‧‧‧Nano Carbon Tube Array Fragments
162‧‧‧第一端 162‧‧‧ first end
164‧‧‧第二端 164‧‧‧ second end
166‧‧‧場發射尖端 166‧‧ ‧ field launch tip
168‧‧‧奈米碳管 168‧‧‧Nano Carbon Tube
20‧‧‧奈米碳管陣列 20‧‧‧Nano Carbon Tube Array
22‧‧‧基底 22‧‧‧Base
28‧‧‧第一電極 28‧‧‧First electrode
30‧‧‧第二電極 30‧‧‧second electrode
圖1係本技術方案實施例所提供的場發射體的結構示意圖。 FIG. 1 is a schematic structural diagram of a field emitter provided by an embodiment of the present technical solution.
圖2係本技術方案實施例所提供的場發射體中奈米碳管陣列片斷的掃描電鏡照片。 2 is a scanning electron micrograph of a carbon nanotube array segment in a field emitter provided by an embodiment of the present technical solution.
圖3係本技術方案實施例所提供的場發射體的場發射尖端的掃描電鏡照片。 FIG. 3 is a scanning electron micrograph of a field emission tip of a field emitter provided by an embodiment of the present technical solution.
圖4係本技術方案實施例所提供的場發射體的電子發射端的拉曼光譜圖。 4 is a Raman spectrum diagram of an electron-emitting end of a field emitter provided by an embodiment of the present technical solution.
圖5係本技術方案實施例所提供的場發射體的場發射電壓與場發射電流的關係圖。 FIG. 5 is a diagram showing a relationship between a field emission voltage and a field emission current of a field emitter provided by an embodiment of the present technical solution.
圖6係本技術方案實施例所提供的場發射體的製備方法的流程圖。 FIG. 6 is a flow chart of a method for preparing a field emitter provided by an embodiment of the present technical solution.
圖7係本技術方案實施例所提供的場發射體的製備工藝流程圖。 FIG. 7 is a flow chart of a process for preparing a field emitter provided by an embodiment of the present technical solution.
10‧‧‧場發射體 10‧‧‧ Field Emitter
14‧‧‧導電基體 14‧‧‧Electrical substrate
16‧‧‧奈米碳管陣列片斷 16‧‧‧Nano Carbon Tube Array Fragment
162‧‧‧第一端 162‧‧‧ first end
164‧‧‧第二端 164‧‧‧ second end
166‧‧‧場發射尖端 166‧‧ ‧ field launch tip
168‧‧‧奈米碳管 168‧‧‧Nano Carbon Tube
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| US20020067114A1 (en) * | 2000-12-05 | 2002-06-06 | Choi Sung Yool | Field emission devices using carbon nanotubes and method thereof |
| WO2003049134A1 (en) * | 2001-11-30 | 2003-06-12 | Sony Corporation | Electron emitter, cold-cathode field electron emitter, and method for manufacturing cold-cathode field electron emission display |
| JP2007161575A (en) * | 2005-12-13 | 2007-06-28 | Samsung Sdi Co Ltd | Method for producing carbon nanotube and field emission device by utilizing the same |
| JP2007287699A (en) * | 1998-09-21 | 2007-11-01 | Lucent Technol Inc | Method for manufacturing carbon nanotube film device |
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| JP2007287699A (en) * | 1998-09-21 | 2007-11-01 | Lucent Technol Inc | Method for manufacturing carbon nanotube film device |
| US20020067114A1 (en) * | 2000-12-05 | 2002-06-06 | Choi Sung Yool | Field emission devices using carbon nanotubes and method thereof |
| WO2003049134A1 (en) * | 2001-11-30 | 2003-06-12 | Sony Corporation | Electron emitter, cold-cathode field electron emitter, and method for manufacturing cold-cathode field electron emission display |
| JP2007161575A (en) * | 2005-12-13 | 2007-06-28 | Samsung Sdi Co Ltd | Method for producing carbon nanotube and field emission device by utilizing the same |
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