200827473 九、發明說明： 【發明所屬之技術領域】 本發明涉及-種奈米碳管陣列的製備方法盆 採用雷射漏化學氣相沈積法製備奈米碳管的方 【先前技術】 ^云。 奈米石炭管係九十年代初才發現的_種新型—維太 料。奈米碳管的特殊結構決定了其具有特殊的性質=高 抗張強度與高熱敎性奈米碳管螺旋方式的變化了 奈米碳管可呈現出金屬性或半導體性等。由於奈米碳管具 有理想的-輯構以及在力學、電學、熱學等領域優良的 性質，其在材料鮮、化學、物理科交又學科領域已展 現出廣_制前景，在科學研究以及產業制上也受到 越來越多的關注。 目箣比較成沾的製備奈米碳管的方法主要包括電弧放 電法（Arc discharge)、雷射燒蝕法（Laser Ablati〇n)及化 + 氣相沈積法（Chemical Vapor Deposition)。其中，化學 氣相沈積法與前兩種方法相比具有產量高、可控性強、與 現行的積體電路工藝相相容等優點，便於工業上進行大規 模合成，因此近幾年備受關注。 用於製備奈米碳管的化學氣相沈積法一般包括傳統熱 化學氣相沈積法（Thermal Chemical Vapor Deposition， CVD)、等離子化學氣相沈積法（piasma chemical Vapor Deposition，PCVD)與雷射辅助化學氣相沈積法 (Laser-Induced Chemical Vapor Deposition， LICVD)。 200827473 • 先前的雷射輔助化學氣相沈積法一般以雷射為快速加 ' 雷射光束直接騎在生長所f的基底上使其 ’皿度升向’達到生長所需的溫度。當含碳反應氣體流經高 溫基底表面時，受基底影響升溫，通過與基底上的催化劑 作用，反應氣體產生熱解或化學反應，從而實現奈米碳管 的生長。 然而，先前的雷射辅助化學氣相沈積法生長奈米碳管 • 有以下不足之處：首先，該方法一般需要在一密封的反應 爐内進行，並使得反應氣體充滿整個反應空間，其設備較 為複雜，且難以製作大型的反應爐用於在大面積玻璃基板 上通過化學氣相沈積法生長奈米碳管。其次，該方法採用 雷射光束直接正面照射在奈米碳管生長所需的基底上，由 於雷射場強度較高，容易破壞奈米碳管的生長。 有鑒於此，提供一種改進的雷射辅助化學氣相沈積 法，其無需在密封的反應室，且可儘量減少正面照射時雷 % 射對奈米碳管生長的破壞實為必要。 【發明内容】 一種奈米碳管陣列的製備方法，其包括以下步 驟：提供一基底；形成一光吸收層於上述基底表面； 形成一催化劑層於上述光吸收層上；通入碳源氣與載 氣的混合氣體流經上述催化劑表面；以及，以雷射光 束聚焦照射在上述基底表面從而生長奈米碳管陣列。 相較於先前技術，所述的奈米碳管陣列的製備方 法形成有一光吸收層位於催化劑層與基底之間。該光 7 200827473 ^ 吸收層可有效吸收雷射能量並加熱催化劑，可削弱雷 射光場強度，可在一定程度上避免雷射光破壞新生長 出來的奈求碳管；同時，在反應過程中可釋放碳原子 促進奈米碳管的成核及生長，因此，本發明實施例奈 米碳管陣列的製備方法無需在一密封的反應室内進 行，方法簡單可控。 【實施方式】 下麵將結合附圖對本發明作進一步的詳細說明。 • 請參閱圖1，本發明實施例奈米碳管陣列的製備方 法主要包括以下幾個步驟： 步驟一：提供一基底。 本實施例中基底材料選用耐南溫材料製成。根據 不同應用，本實施例中基底材料還可分別選用不同材 料，如，當應用於半導體電子器件時可選擇為矽、二 氧化矽或金屬材料；當應用于平板顯示器時，優選為 玻璃。基底本身厚度不影響本實施例奈米碳管陣列的 生長，其也可根據實際應用選擇不同厚度。 步驟二：在上述基底表面形成一光吸收層。 本實施例中，該光吸收層的製備方法包括以下步 驟：將一含碳材料塗敷於上述基底表面，該含碳材料 要求能與基底表面結合緊密；在氮氣環境中，將塗敷 有含碳^材料的基底在約9 0分鐘内逐漸加溫到約3 0 0 °C以上，並烘烤一段時間；自然冷卻到室溫形成一光 吸收層於基底表面。 8 200827473 > 本發明實施例中含碳材料優選為目前廣泛應用於 電子產品如冷陰極顯像管中的石墨乳材料。進一步 ^ 地，該石墨乳可通過旋轉塗敷方式形成於基底表面， 其轉速為1000〜5000轉/分（rpm)，優選為1500rpm。 所形成的光吸收層的厚度為1〜20微米。另，烘烤的 目的在於使得含碳材料中的其他材料蒸發，如將石墨 乳中的有機物蒸發。 步驟三：形成一催化劑層於上述光吸收層上。 _ 該催化劑層的形成可利用熱沈積、電子束沈積或 濺射法來完成。催化劑層的材料選用鐵，也可選用其 他材料，如氮化鎵、钻、鎳及其合金材料等。進一步 地，可通過高溫退火等方式氧化催化劑層，形成催化 劑氧化物顆粒。 另，該催化劑層可通過將一催化劑溶液塗敷於光 吸收層上形成，其具體步驟包括：提供一催化劑乙醇 溶液；將該催化劑乙醇溶液塗敷於上述光吸收層表 • 面。 本實施例中，該金屬硝酸鹽化合物包括硝酸鎂 (Mg(N〇3)2*6H2〇)與石肖酸鐵（Fe(N〇3)3*9H2〇)、石肖酸钻 (Co(N〇3)2· 6H2〇)或硝酸鎳（Ni(N〇3)2· 6H2O)中任一種或 幾種組成的混合物。本實施例優選為將硝酸鐵 (Fe(N〇3)3 · 9H2〇)與頌酸鎂（Mg(N〇3)2 · 6H2O)加入到溶液 中形成催化劑溶液，該催化劑溶液中含有0. 01〜0. 5 摩爾（Mol/L)的石肖酸鎂與0· 01〜0· 5Mol/L的硝酸鐵。 200827473 該催化劑乙醇溶液可通過旋轉塗敷形成於光吸收層 表面，其轉速優選為約1500rpm。所形成的催化劑層 的厚度為1〜100奈米。 步驟四：通入碳源氣與載氣的混合氣體流經上述 催化劑表面。200827473 IX. Description of the Invention: [Technical Field] The present invention relates to a method for preparing a carbon nanotube array. A method for preparing a carbon nanotube by a laser leakage chemical vapor deposition method [Prior Art] ^Cloud. The nano-carboniferous pipe is a new type of weitai material that was discovered in the early 1990s. The special structure of the carbon nanotubes determines its special properties = high tensile strength and high enthalpy carbon nanotube spiral mode changes. Carbon nanotubes can exhibit metallic or semiconducting properties. Because carbon nanotubes have ideal-composition and excellent properties in the fields of mechanics, electricity, heat, etc., they have shown broad prospects in the fields of fresh materials, chemistry, and physics, in scientific research and industry. The system has also received more and more attention. The methods for preparing carbon nanotubes by comparison are mainly including arc discharge, laser ablation (Laser Ablati〇n) and chemical vapor deposition (Chemical Vapor Deposition). Among them, the chemical vapor deposition method has the advantages of high yield, strong controllability, compatibility with the current integrated circuit process, and the like, and is convenient for industrial large-scale synthesis, so it has been accepted in recent years. attention. Chemical vapor deposition methods for preparing carbon nanotubes generally include conventional thermal chemical vapor deposition (CVD), piasma chemical Vapor Deposition (PCVD) and laser-assisted chemistry. Laser-Induced Chemical Vapor Deposition (LICVD). 200827473 • Previous laser-assisted chemical vapor deposition methods generally used lasers to rapidly add 'laser beams' directly on the substrate of the growth site to raise the temperature to the temperature required for growth. When the carbon-containing reaction gas flows through the surface of the high-temperature substrate, it is heated by the substrate, and by reacting with the catalyst on the substrate, the reaction gas generates a pyrolysis or a chemical reaction, thereby realizing the growth of the carbon nanotubes. However, the previous laser-assisted chemical vapor deposition method for growing carbon nanotubes has the following disadvantages: First, the method generally needs to be carried out in a sealed reactor and the reaction gas is filled throughout the reaction space. It is complicated and it is difficult to make a large-scale reactor for growing carbon nanotubes by chemical vapor deposition on a large-area glass substrate. Secondly, the method uses a laser beam to directly illuminate the substrate required for the growth of the carbon nanotubes. Because of the high intensity of the laser field, it is easy to destroy the growth of the carbon nanotubes. In view of this, an improved laser assisted chemical vapor deposition process is provided which does not require a sealed reaction chamber and which minimizes the damage of the carbon nanotube growth during frontal illumination. SUMMARY OF THE INVENTION A method for preparing a carbon nanotube array includes the steps of: providing a substrate; forming a light absorbing layer on the surface of the substrate; forming a catalyst layer on the light absorbing layer; and introducing a carbon source gas and A mixed gas of a carrier gas flows through the surface of the catalyst; and a laser beam is focused on the surface of the substrate to grow an array of carbon nanotubes. Compared to the prior art, the carbon nanotube array is prepared by forming a light absorbing layer between the catalyst layer and the substrate. The light 7 200827473 ^ The absorption layer can effectively absorb the laser energy and heat the catalyst, which can weaken the intensity of the laser light field, and can prevent the laser light from destroying the newly grown carbon tube to some extent; at the same time, it can be released during the reaction The carbon atoms promote the nucleation and growth of the carbon nanotubes. Therefore, the preparation method of the carbon nanotube array of the embodiment of the present invention does not need to be carried out in a sealed reaction chamber, and the method is simple and controllable. [Embodiment] Hereinafter, the present invention will be further described in detail with reference to the accompanying drawings. Please refer to FIG. 1. The method for preparing a carbon nanotube array according to an embodiment of the present invention mainly includes the following steps: Step 1: Provide a substrate. In this embodiment, the base material is made of a material resistant to southermost materials. Depending on the application, the substrate material in this embodiment may also be selected from different materials, for example, when used in a semiconductor electronic device, bismuth, germanium dioxide or a metal material; when applied to a flat panel display, glass is preferred. The thickness of the substrate itself does not affect the growth of the carbon nanotube array of this embodiment, and it is also possible to select different thicknesses depending on the actual application. Step 2: forming a light absorbing layer on the surface of the substrate. In this embodiment, the method for preparing the light absorbing layer comprises the steps of: applying a carbonaceous material to the surface of the substrate, the carbonaceous material is required to be tightly bonded to the surface of the substrate; and in a nitrogen atmosphere, the coating is contained. The substrate of the carbon material is gradually heated to above about 300 ° C in about 90 minutes and baked for a period of time; it is naturally cooled to room temperature to form a light absorbing layer on the surface of the substrate. 8 200827473 > The carbonaceous material in the embodiment of the present invention is preferably a graphite emulsion material which is currently widely used in electronic products such as cold cathode picture tubes. Further, the graphite emulsion may be formed on the surface of the substrate by spin coating at a rotational speed of 1000 to 5000 rpm, preferably 1500 rpm. The thickness of the light absorbing layer formed is 1 to 20 μm. In addition, the purpose of baking is to evaporate other materials in the carbonaceous material, such as evaporating organic matter in the graphite emulsion. Step 3: forming a catalyst layer on the light absorbing layer. The formation of the catalyst layer can be accomplished by thermal deposition, electron beam deposition or sputtering. The material of the catalyst layer is iron, and other materials such as gallium nitride, diamond, nickel and alloy materials thereof may also be used. Further, the catalyst layer may be oxidized by high temperature annealing or the like to form catalyst oxide particles. Alternatively, the catalyst layer may be formed by applying a catalyst solution to the light absorbing layer, the specific steps comprising: providing a catalyst ethanol solution; and applying the catalyst ethanol solution to the surface of the light absorbing layer. In this embodiment, the metal nitrate compound comprises magnesium nitrate (Mg(N〇3)2*6H2〇) and iron oxalate (Fe(N〇3)3*9H2〇), and stone osmotic acid drill (Co( N〇3)2·6H2〇) or a mixture of any one or several of nickel nitrate (Ni(N〇3)2·6H2O). In this embodiment, ferric nitrate (Fe(N〇3)3·9H2〇) and magnesium niobate (Mg(N〇3)2·6H2O) are added to the solution to form a catalyst solution, and the catalyst solution contains 0. 01~0. 5 moles (Mol/L) of magnesium sulphate and 0. 01~0·5Mol/L of ferric nitrate. 200827473 The catalyst ethanol solution can be formed on the surface of the light absorbing layer by spin coating, and the rotation speed thereof is preferably about 1500 rpm. The resulting catalyst layer has a thickness of from 1 to 100 nm. Step 4: a mixed gas of a carbon source gas and a carrier gas is passed through the surface of the catalyst.
該碳源氣優選為廉價氣體乙炔，也可選用其他碳 氫化合物如甲烷、乙烷、乙烯等。載氣氣體優選為氬 氣，也可選用其他惰性氣體如氮氣等。本實施例中， 碳源氣與載氣可通過一氣體喷嘴直接通入到上述催 化劑層表面附近。載氣與複源氣的通氣流量比例為 5 : 1〜10 : 1，本實施例優選為通以約200標準毫升/ 分（seem)的氬氣和約25sccm的乙炔。 步驟五：以雷射光束聚焦照射在上述基底表面從 而生長奈米碳管陣列。 本實施例中，雷射光束可通過傳統的氬離子雷射 器或二乳化石厌雷射器產生’其功率為0〜5W，優選為約 960mW。產生的雷射光束可通過一透鏡聚焦後從正面 直接照射在上述基底表面，可以理解，該雷射光束可 採用垂直照射或傾斜照射聚焦於基底表面的催彳匕象 層上。 劑 反應預定時間後，由於催化 …' Μ及雷肩 光束照.射在基底催化劑層上加熱催化劑，通 附近的碳源氣在一定溫度下熱解成;ε炭單元土 ’丨The carbon source gas is preferably an inexpensive gas acetylene, and other hydrocarbons such as methane, ethane, ethylene, or the like may also be used. The carrier gas is preferably argon, and other inert gases such as nitrogen may also be used. In this embodiment, the carbon source gas and the carrier gas can be directly introduced into the vicinity of the surface of the catalyst layer through a gas nozzle. The ratio of the aeration flow rate of the carrier gas to the regenerated gas is 5:1 to 10:1, and this embodiment is preferably argon gas of about 200 standard milliliters per minute (seem) and acetylene of about 25 seem. Step 5: The carbon nanotube array is grown by focusing the laser beam on the surface of the substrate. In this embodiment, the laser beam can be produced by a conventional argon ion laser or a two-emulsified stone anti-laser. The power is 0 to 5 W, preferably about 960 mW. The generated laser beam can be directly focused on the surface of the substrate from the front surface by focusing with a lens. It can be understood that the laser beam can be focused on the surface of the substrate by vertical or oblique illumination. After a predetermined reaction time, the catalyst is heated on the base catalyst layer by catalysis, and the carbon source gas is pyrolyzed at a certain temperature; ε carbon unit soil 丨
和氫氣。其中，氫氣會將被氧化的催化為丨_ ^ C μ還原，啖』 200827473 =於催化劑層表面’從而生長出奈爾。本實 由於採用雷射作為加熱熱源，且利用石墨 射能量並加熱催化劑，該化學氣相沈積法的 反應>里度可低於600攝氏度。 照:催:：二發二：：:“ 應的碳源氣’從而使氣體能量增加，；1 :二反And hydrogen. Among them, hydrogen will oxidize the catalyzed 丨 ^ ^ C μ reduction, 啖 2008 200827473 = on the surface of the catalyst layer 'and thus grow neil. In this case, since the laser is used as a heating heat source and the graphite is used to ignite energy and heat the catalyst, the reaction of the chemical vapor deposition method can be less than 600 degrees Celsius. Photo: reminder:: two hair two::: "should carbon source gas" to increase the gas energy;
来丨財發明實施例制雷㈣—射生長奈 二：二令足糾催化劑局部溫度在較短時間内能夠被加 r孰㈣的能量’同時，碳源氣為直接通入到被 近。因此’本發明實施例無需- ==所需的溫度及碳源氣的濃度，且： 化劑能夠被還原，並促使奈米碳管陣列=乳化的催 射輔例中形成的石墨乳層在本發明利用雷 以下俨點二：沈積法生長奈米碳管陣列的方法有 並加二化Γ可=石墨乳層能有效吸收雷射能量 y 了使传該催化劑層更容易達到生長奈 t'反二而溫度’本實施例中反應溫度可低於600 ，一，該石墨乳層可削弱雷射場強度，可在一宏 程度上避免雷射破壞新生長出來的奈米碳管，·第三， 11 200827473 該石墨乳層在反應過程中可釋放出碳原子促進奈米 鼉 碳管的成核及生長，因此，本發明實施例奈米碳管陣 列的製備方法無需在一密封的反應室内進行，方法簡 單可控。 請參閱圖2,本發明實施例依照上述方法以聚焦後 直徑範圍在50〜200微米的雷射光束垂直照射在玻璃 基底的催化劑上約30秒鐘，可得到如圖2所示的奈 米碳管陣列。該奈米碳管陣列為山丘形狀，且垂直於 • 基底生長。該奈米碳管陣列的直徑為100〜200微米， 高度為10〜20微米。每個奈米碳管的直徑為10〜30奈 進一步地，本實施例雷射輔助化學氣相沈積法生 長奈米碳管陣列過程中，可通過控制移動雷射光束掃 描照射在基底的催化劑層上，可實現大面積基底上生 長奈米碳管陣列。 _ 綜上所述，本發明確已符合發明專利之要件，遂 依法提出專利申請。惟，以上所述者僅為本發明之較 佳實施例，自不能以此限制本案之申請專利範圍。舉 凡熟悉本案技藝之人士援依本發明之精神所作之等 效修飾或變化，皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 圖.1係本發明實施例奈米碳管陣列的製造方法的 流程示意圖。 圖2係本發明實施例獲得的奈米碳管陣列的掃描 12 200827473 電鏡照片。 【主要元件符號說明】 無In the case of the invention of the invention, the thunder (4)-shooting growth nai 2: the local temperature of the two-step correcting catalyst can be increased by the energy of the r (4) while the carbon source gas is directly connected to the vicinity. Therefore, the embodiment of the present invention does not require - == the required temperature and the concentration of the carbon source gas, and: the agent can be reduced, and the graphite layer formed in the carbon nanotube array = emulsified auxiliaries is formed at The invention utilizes the following method: the method for growing the carbon nanotube array by the deposition method is that the graphite layer can effectively absorb the laser energy y, so that the catalyst layer can be more easily reached. In the second embodiment, the reaction temperature can be lower than 600. First, the graphite emulsion layer can weaken the intensity of the laser field, and can avoid the laser to destroy the newly grown carbon nanotubes in a macroscopic degree. , 11 200827473 The graphite emulsion layer can release carbon atoms during the reaction to promote the nucleation and growth of the carbon nanotubes. Therefore, the preparation method of the carbon nanotube array of the embodiment of the invention does not need to be performed in a sealed reaction chamber. The method is simple and controllable. Referring to FIG. 2, in the embodiment of the present invention, a laser beam having a diameter ranging from 50 to 200 micrometers after focusing is vertically irradiated on the catalyst of the glass substrate for about 30 seconds, thereby obtaining a nanocarbon as shown in FIG. Tube array. The carbon nanotube array is in the shape of a hill and grows perpendicular to the substrate. The carbon nanotube array has a diameter of 100 to 200 microns and a height of 10 to 20 microns. Each of the carbon nanotubes has a diameter of 10 to 30. Further, in the laser assisted chemical vapor deposition method for growing the carbon nanotube array in this embodiment, the catalyst layer irradiated on the substrate can be scanned by controlling the moving laser beam. On top, a carbon nanotube array can be grown on a large area substrate. _ In summary, the present invention has indeed met the requirements of the invention patent, and 提出 filed a patent application according to law. However, the above is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application in this case. Equivalent modifications or variations made by those skilled in the art to the spirit of the invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic flow chart showing a method of manufacturing a carbon nanotube array according to an embodiment of the present invention. 2 is a scanning of a carbon nanotube array obtained in an embodiment of the present invention. 12 200827473 Electron micrograph. [Main component symbol description] None
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