1311591 九、發明說明： 【發明所屬之技術領域】 陣列的製備方法’尤其涉及 製備奈米碳管陣列的方法。 本發明涉及一種奈米碳管 採用雷射輔助化學氣相沈積法 【先前技術】1311591 IX. Description of the Invention: [Technical Field of the Invention] The method of preparing an array' particularly relates to a method of preparing a carbon nanotube array. The invention relates to a carbon nanotube tube using a laser assisted chemical vapor deposition method [Prior Art]
料；=二代初才發現的-種新型-維奈米材 4奈未奴官的特殊結構決定了其具有特殊的 ^張強度與高絲紐；_奈米碳管職方式的變化 不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-_構以及在力學、電學、熱料領域優良的 性質，其在科學、化學、物理料蚊學科領域已展 現出廣闊的應时景’在科學研纽及產業助上也受到 越來越多的關注。 目前比較成熟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 予氣相沈積法（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)與雷射輔助化學氣相沈積法 (Laser-Induced Chemical Vapor Deposition, LICVD)。 6 1311591 先前的雷射輔助化學氣相沈積法一般以雷射為快速加 熱熱源’利用雷射光束直接照射在生長所需的基底上使其 溫度升高，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。== The first generation of the second generation - the new type - the special structure of the Venaimi 4 Naiwu slave officially determined that it has a special tensile strength and high silk nucleus; _ nano carbon tube position changes the carbon nanotubes It may exhibit metallicity or semiconductivity. Because the carbon nanotubes have an ideal structure and excellent properties in the fields of mechanics, electricity, and hot materials, they have shown a broad time in the field of science, chemistry, and physics, and in the field of science research and industry. Help has also received more and more attention. At present, the more mature methods for preparing carbon nanotubes mainly include arc discharge, laser ablation and laser 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). 6 1311591 Previous laser-assisted chemical vapor deposition methods generally used a laser as a fast heating heat source to directly irradiate a substrate required for growth with a laser beam to raise its 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.
然而’先削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。However, the first-shot 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.
有鑒於此，提供一種改進的雷射輔助化學氣相沈積 法，其無需在密封的反應室，且可儘量減少正面照射時^ 射對奈米碳管生長的破壞實為必要。 【發明内容】 種奈米碳管陣列的製 ，、Μ下步 驟：提供一基底；形成一光吸收層於上述基底表. 形成-催化劑層於上述光吸收層上；通人碳源氣^ 氣的混合氣體流經上述催化劑表面；以及， 人从雷射光 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 1311591 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 出來的奈米碳管；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高溫材料製成。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90分鐘内逐漸加溫到約300 °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。 1311591 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 鲁 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)與硝酸鐵（Fe(N〇3)3.9H2〇)、硝酸姑 (Co(N〇3)2 · 6H2〇)或硝酸鎳（Ni (N〇3)2 · 6H2〇)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)與确酸鎮（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)的硝酸鎂與0.01〜0.5M〇1/L的硝酸鐵。 1311591 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。 該碳源氣優選為廉價氣體乙炔，也可選用其他碳 氳化合物如甲烷、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。載氣與碳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的乙块。 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 器或二氧化碳雷射器產生，其功率為0〜5W，優選為約 參 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化劑 層上。 反應預定時間後，由於催化劑的作用，以及雷射 光束照射在基底催化劑層上加熱催化劑，通入到基底 附近的碳源氣在一定溫度下熱解成碳單元（C=C或C) 和氫氣。其中，氫氣會將被氧化的催化劑還原，碳單 1311591 元吸附於催化劑層表面，從而生長出奈米碳管。本實 施例中，由於採用雷射作為加熱熱源，且利用石墨乳 層吸收雷射能量並加熱催化劑，該化學氣相沈積法的 反應溫度可低於600攝氏度。 進一步地，由於本發明實施例採用雷射聚焦正面 照射催化劑生長奈米碳管陣列，利用雷射光束照射反 應的碳源氣，從而使氣體能量增加，提高氣體溫度， 可進一步促進碳源氣在較低溫度分解反應生長奈米 • 碳管陣列。 另，由於本發明實施例採用雷射聚焦照射生長奈 米碳管陣列，催化劑局部溫度在較短時間内能夠被加 熱並吸收足夠的能量，同時，碳源氣為直接通入到被 加熱的催化劑表面附近。因此，本發明實施例無需一 密封的反應室，即可同時保證生長奈米碳管陣列的催 化劑附近達到所需的溫度及碳源氣的濃度，且，由於 碳源氣分解產生的氳氣的還原作用，可確保氧化的催 化劑能夠被遠原，並促使奈米礙管陣列生長。 本發明實施例中形成的石墨乳層在本發明利用雷 射輔助化學氣相沈積法生長奈米碳管陣列的方法有 以下優點：第一，由於石墨乳層能有效吸收雷射能量 並加熱催化劑，可使得該催化劑層更容易達到生長奈 • 米碳管所需溫度，本實施例中反應溫度可低於600 °C ;第二，該石墨乳層可削弱雷射場強度，可在一定 程度上避免雷射破壞新生長出來的奈米碳管；第三， 11 1311591 該石墨乳層在反應過程中可釋放出碳原子促進奈米 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。 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 米。 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 流程不意圖。 圖2係本發明實施例獲得的奈米碳管陣列的掃描 12 1311591 電鏡照片。 【主要元件符號說明】 無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 damage to the growth of the carbon nanotubes during frontal illumination. SUMMARY OF THE INVENTION A carbon nanotube array is fabricated, a step of squatting: providing a substrate; forming a light absorbing layer on the substrate surface; forming a catalyst layer on the light absorbing layer; and introducing a carbon source gas The mixed gas flows through the surface of the catalyst; and a person focuses the laser beam from the surface of the substrate to grow the carbon nanotube array. 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 1311591 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 nanotubes to some extent; at the same time, the carbon atoms can be released during the reaction. The nucleation and growth of the carbon nanotubes are promoted. Therefore, the preparation method of the carbon nanotube array of the embodiment of the 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 the embodiment, the base material is made of a high temperature resistant material. 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 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; in a nitrogen atmosphere, the coating is applied The substrate of the carbonaceous material is gradually warmed to about 300 ° C or more 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. 1311591 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 number of revolutions of 1000 to 5000 rpm, preferably 1,500 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 step 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 ferric nitrate (Fe(N〇3)3.9H2〇), and nitrate (Co(N〇3)2). · 6H2〇) or a mixture of any one or several of nickel nitrate (Ni (N〇3) 2 · 6H2 〇). In this embodiment, it is preferred to add ferric nitrate (Fe(N〇3)3·9H2〇) and acid (Mg(N〇3)2·6H2O) to the solution to form a catalyst solution, and the catalyst solution contains 0. 01 to 0.5 mol% (Mol/L) of magnesium nitrate and 0.01 to 0.5 M〇1/L of ferric nitrate. 1311591 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 formed 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. The carbon source gas is preferably an inexpensive gas acetylene, and other carbon ruthenium compounds 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 carbon source gas is 5:1 to 10:1, and this embodiment is preferably an argon gas of about 200 standard milliliters per minute (seem) and an ethylene block 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 generated by a conventional argon ion laser or carbon dioxide laser having a power of 0 to 5 W, preferably about 960 mW. The resulting laser beam can be focused by a lens and directly irradiated from the front surface to the surface of the substrate. It is understood that the laser beam can be focused on the catalyst layer on the surface of the substrate by vertical or oblique illumination. After a predetermined reaction time, the carbon source gas introduced into the vicinity of the substrate is pyrolyzed into a carbon unit (C=C or C) and hydrogen at a certain temperature due to the action of the catalyst and the laser beam is irradiated on the base catalyst layer to heat the catalyst. . Among them, hydrogen will reduce the oxidized catalyst, and carbon monocarbonate 1311591 yuan adsorbed on the surface of the catalyst layer, thereby growing carbon nanotubes. In the present embodiment, since the laser is used as the heating heat source and the graphite emulsion layer is used to absorb the laser energy and heat the catalyst, the reaction temperature of the chemical vapor deposition method may be lower than 600 °C. Further, since the embodiment of the present invention uses a laser focused front-illuminated catalyst to grow a carbon nanotube array, the laser source is used to irradiate the reacted carbon source gas, thereby increasing the gas energy and increasing the gas temperature, thereby further promoting the carbon source gas. The lower temperature decomposition reaction grows the nano carbon tube array. In addition, since the embodiment of the present invention uses the laser focused irradiation to grow the carbon nanotube array, the local temperature of the catalyst can be heated and absorb sufficient energy in a short time, and at the same time, the carbon source gas is directly passed to the heated catalyst. Near the surface. Therefore, the embodiment of the present invention can simultaneously ensure that the desired temperature and the concentration of the carbon source gas are reached in the vicinity of the catalyst for growing the carbon nanotube array without a sealed reaction chamber, and the helium gas generated by the decomposition of the carbon source gas. The reduction ensures that the oxidized catalyst is able to be removed from the far field and causes the nanotube to block the growth of the array. The graphite emulsion layer formed in the embodiment of the invention has the following advantages in the method for growing a carbon nanotube array by laser assisted chemical vapor deposition in the present invention: first, since the graphite emulsion layer can effectively absorb the laser energy and heat the catalyst The catalyst layer can be more easily reached to the temperature required for growing the carbon nanotubes. In this embodiment, the reaction temperature can be lower than 600 ° C. Second, the graphite emulsion layer can weaken the intensity of the laser field, to a certain extent. Avoiding laser damage to the newly grown carbon nanotubes; Third, 11 1311591 The graphite emulsion layer can release carbon atoms during the reaction to promote nucleation and growth of the carbon nanotubes. Therefore, the present invention is a nanometer. Carbon tube array: The preparation method of the column does not need to be carried out in a sealed reaction chamber, and 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 carbon nanotube has a diameter of 10 to 30 nm. Further, in the process of growing the carbon nanotube array by the laser assisted chemical vapor deposition method of the present embodiment, the nano-area growth carbon nanotube can be realized by controlling the moving laser beam to be irradiated onto the catalyst layer of the substrate. Array. 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 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 electron micrograph of a carbon nanotube array obtained in an embodiment of the present invention. [Main component symbol description] None
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