200827475 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，尤立涉及 採用雷射漏化學氣概製備奈米碳 方法。 【先前技術】 奈米碳管係九十年代初發現的—種新型—維夺米材 料。奈米碳管的特殊結構決定其具有特殊的性質，如高抗 • 與高熱穩定性，·隨著奈米碳管螺旋方式的變化，奈 米碳管可呈現出金屬性或半導體性等。由於奈米碳管且有 理想的-維結構以及在力學、電學、熱學等領域優良的性. 質，其在材料科學、化學、物理學等交叉學科領域已展現 出廣闊的應用前景，在科學研究以及產業應用上也受到越 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 Ablation)及化 鲁 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 先鈾的積體電路工藝相容等優點，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先前熱 化學氣相沈積法（Thermal Chemical Vapor Deposition， CVD )、電漿化學氣相沈積法（piasma chemical Vapor Deposition，PCVD)與雷射辅助化學氣相沈積法 (Laser-Induced Chemical Vapor Deposition ， LICVD)。 6 200827475 先前的雷射辅助化學氣相沈積法一般以雷射為快速加 熱熱源’彻雷射絲直触射在生長所需的基底上使其 溫度升高’朗生長所需的溫度。#含碳反應氣體流經高 溫基絲面時，錄絲響升溫，通過與基底上的催化劑 作用，反應氣體產生鱗或化學反應，從而實财米碳管 的生長。 先月ίΐ的雷射輔助化學氣相沈積法生長奈米碳管通常採 用固體雷射H或氣體雷射||。其巾，目體雷射器包括如換 敍釔鋁石榴石（M:YAG)雷射器或氬離子雷射器等；氣體 雷射器包括二氧化碳雷射器等。上述雷射器的光束品質都 很好，惟，上述雷射器一般是單模或多模的，且上述雷射 器一般體積都很大，且對環境要求很高。進一步地，上述 雷射器一般還需要有對應的水冷系統和溫度控制系統、價 格昂貴的電源以及很好的防震系統與光學系統。以上缺點 都將不同程度地限制應用上述雷射器的雷射辅助化學氣相 沈積法生長奈米碳管。另，先前的使用固體與氣體雷射器 的雷射輔助化學氣相沈積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基板上通過化 學氣相沈積法生長奈米碳管。 相對於上述固體與氣體雷射器，先前的半導體雷射器 具有體積小、成本低的優點。具體地，先前的半導體雷射 器一般不需要水冷系統，普通的散熱片就可以實現散熱， 且不需要溫度控制，設備簡單，使用方便。另，先前的半 7 200827475 導體雷射器只需普通恆流電源，也不需要很好的防震系統 與光學系統。然而，先前的雷射輔助化學氣相沈積法生長 奈米碳管沒有採用半導體雷射器。 有馨於此’確有必要提供一種應用半導體雷射器的雷 射輔助化學氣相沈積生長奈米碳管陣列的方法。 【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；在上述基底一表面形成一催化劑 層’通入峻源氣與載氣的混合氣體流、纟至上述催化劑層 表面；以及提供一半導體雷射器系統發出雷射光束聚 焦照射在上述基底上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 法採用半導體雷射器產生的雷射光束照射生長奈米 碳管陣列，利用半導體雷射器尺寸小，耦合效率高， 回應速度快，波長與尺寸與光纖尺寸適配，可直接調 製，相干性好等特性，本發明實施例奈米碳管陣列的 製備方法具有成本低，可控性強等優點。另，由於半 導體雷射器比氣體雷射器的波長更短，且半導體雷射 器的雷射光束成方波分佈，更有利於基底與催化劑的 决速加熱。且，由於採用含碳催化劑層或光吸收層， 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，因此簡單可控。 【實施方式】 以下將結合附圖對本發明作進一步的詳細說明。 200827475 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透明或 不透明材料，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等不透明材料；當應用於 大面積平板顯示器時，優選為玻璃、可塑性有機材料 等透明材料。 步驟二：在上述基底的一表面均勻形成一催化劑 層0 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、銘、錄及其合金材料等。進一步 地，該催化劑層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，本發明實施例催化劑層也可選用形成一種含 碳的催化劑層，或者在該催化劑層與基底之間預先形 成一光吸收層。 當選用形成一種含碳的催化劑層時，該含碳的催 化劑層的製備方法包括以下步驟：提供一種分散劑與 一種含碳物質的混合物，並與一溶劑混合形成溶液； 將該溶液進行超聲波處理分散；在該分散後的溶液中 加入金屬硝酸鹽混合物溶解得到一催化劑溶液；將該 9 200827475 催化劑溶液均勻塗敷於基底表面；烘烤該塗敷有催化 劑浴液的基底從而在基底表面形成一含碳的催化劑 層。 其中，該含碳物質包括碳黑或石墨等含碳材料。 該分散劑用於將含碳物質均勻分散，優選為十二烧基 苯石黃酸鈉（Sodium Dodecyl Benzene Sulfonate, SDBS)。溶劑可選擇為乙醇溶液或水。該分散劑與含 碳物質的品質比為1:2〜1:10,本實施例優選為將 〇〜100毫克的十二烷基苯磺酸鈉與100〜500毫克的碳 黑混合物與乙醇溶液混合形成溶液。 該金屬硝酸鹽混合物包括硝酸鎂（Mg(N〇3)2.6H2〇) 與硝酸鐵（Fe(N〇3)3.9H2〇)、硝酸鈷（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)與硝酸鎂 (Mg(N〇3)r6H2〇)加入到溶液中形成催化劑溶液，該催 化劑溶液中含有〇·〇1〜0.5摩爾/升（Mol/L)的硝酸鎂 與0· 01〜0· 5Mol/L的硝酸鐵。 烘烤的溫度為60〜100°C。烘烤的作用為將催化劑 溶液中的溶劑蒸發從而形成一含碳催化劑層。 本實施例中，該含碳的催化劑層的厚度為1〇〜1〇〇 微米。催化劑溶液塗敷於基底表面可採用旋轉塗敷的 方式’其轉速為1000〜5000轉/分（rpm)，優選為 1500rpm 〇 當選用在該催化劑層與基底之間預先形成一光吸 200827475 收層時，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；在保護氣體環境中，將塗敷有含 碳材料的基底逐漸加溫到約3 0 0 C以上，並洪烤一段 時間；自然冷卻到室溫形成一光吸收層於基底表面。 本發明實施例中，保護氣體包括氮氣或惰性氣 體，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 1〇〇〇〜5〇〇〇了0111，優選為15〇〇印111。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条 發。 進一步地，當使用光吸收層時，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，該催化劑乙醇溶液為將金屬硝酸鹽 混合物與乙醇溶液混合形成。該金屬硝酸鹽混合物為 确酸鎂（Mg(N〇3)2,6H2〇)與靖酸鐵（Fe(N〇3)3.9H2〇)、頌 酸钻（Co(N〇3)2 · 6H2O)或石肖酸錄（Ni (Ν〇3)2 · 6H2O)中任一 種或幾種組成的混合物。優選地，該催化劑乙醇溶液 為硝酸鎂與硝酸鐵組成的混合物的乙醇溶液，溶液中 確酸鐵的含量為0.01〜〇. 5Mol/L，石肖酸鎮的含量為 11 200827475 0. 01〜0. 5Mol/L。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。 步驟三：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 氫化合物如曱烷、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。載氣與後源氣的通氣流量比例為 5 : 1〜10 : 1，本實施例優選為通以200標準毫升/分 (seem)的氬氣與25sccm的乙炔。 步驟四：提供一半導體雷射器系統發出雷射光束 聚焦照射在上述基底上從而生長奈米碳管陣列。 請參閱圖2,本實施例中該半導體雷射器系統包括 _ 一雷射二極體12、與該雷射二極體12連接的多模光 纖14及一聚焦透鏡18。該雷射二極體12與該多模光 纖14 一端耦合連接，雷射二極體12產生的雷射光束 16通過多模光纖14的另一端發出，並通過聚焦透鏡 18聚焦後照射在基底22上。 本實施例中，多模光纖14的直徑為20〜100微米。 雷射二極體12的輸出功率為0〜10瓦，產生的雷射波 長為700〜1300奈米。優選地，本實施例雷射二極體 12輸出功率為2瓦，產生的雷射波長優選為808奈 12 200827475 . 米。通過與多模光纖14耦合，並通過聚焦透鏡18聚 焦後，雷射光束16照射在基底22上的光斑直徑^ 5 0〜2 0 〇微米。 # 可以理解，該聚焦後的雷射光束16可從正面直接 照射在上述基底22催化劑層表面，或者如圖2所示， 當基底材料為透明材料或厚度較薄的不透明材料 時，該雷射光束16也可聚焦後照射在基底22的反 _ 面’當雷射光束16照射在基底22的反面時，該雷射 光束16症1可迅速透過基底22傳遞到催化劑層並加 熱催化劑。 反應預疋時間後’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) 與氫氣。其中，氫氣會將被氧化的催化劑還原，碳單 凡吸附於催化劑層表面，從而生長出奈米碳管。另， # 本實施例中，利用含碳催化劑層或光吸收層吸收雷射 月匕置的作用’該化學氣相沈積法反應溫度可低於6〇0 攝氏度。另，該含碳催化劑層或光吸收層可在反應過 私中釋放出碳原子促進奈米碳管的成核及生長。 由於本發明實施例主要利用雷射的熱效應，對雷 射的光學效應要求不高，故通過將雷射二極體12與 夕模光纖14耦合產生多模的雷射光，有利於均勻加 熱催化劑，有效提高雷射功率。另，由於半導體雷射 器比先前氣體雷射器的波長更短，且半導體雷射器的 13 200827475 雷射光束成方波分佈’更有利於基底與催化劑的快速 加熱。 另’由於本發明實施例採用雷射聚焦照射生長夺 米碳管降列’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 碳源氣分解產生的氫氣的還原作用，可確保氧化的催 化劑能夠被還原，並促使奈米碳管陣列生長。 請參閱圖3,當本發明實施例採用含碳的催化劑層 k ’雷射光束垂直地從反面照射在玻璃基底的催化, 上約5秒鐘，可得到如圖3所示的奈米破管陣列。兮 奈米碳管陣列為山丘形狀，且垂直於玻璃基底生手。 該奈米碳管陣列的直徑為50〜80微米，高度為1〇~2〇 微米。每個奈米碳管的直徑為40〜80奈米。 請參閱圖4,當本發明實施例採用石墨乳層作為光 吸收層時形成於基底與催化劑層之間時，採用雷射光 束垂直地從反面照射在玻璃基底的催化劑上約3〇秒 鐘，可得到如圖4所示的奈米碳管陣列。該奈米唆管 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，本實施例雷射辅助化學氣相沈積法生 200827475 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，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備方法的 流程示意圖。 圖2係本發明實施例奈米碳管陣列的製備方法所 用設備的結構示意圖。 圖3係本發明實施例採用含碳催化劑層獲得的奈 米碳管陣列圖形的掃描電鏡照片。 圖4係本發明實施例採用光吸收層獲得的奈米碳 管陣列圖形的掃描電鏡照片。 【主要元件符號說明】 無 15200827475 IX. INSTRUCTIONS: [Technical Field] The present invention relates to a method for preparing a carbon nanotube array, and particularly relates to a method for preparing a nanocarbon using a laser leaking chemical gas. [Prior Art] The carbon nanotubes were discovered in the early 1990s as a new type of vitamin-winning material. The special structure of the carbon nanotubes determines its special properties, such as high resistance and high thermal stability. · With the change of the helical shape of the carbon nanotubes, the carbon nanotubes can exhibit metallic or semiconducting properties. Due to its ideal-dimensional structure and its excellent properties in mechanics, electricity, and thermals, nanocarbon tubes have shown broad application prospects in the fields of materials science, chemistry, and physics. Research and industrial applications are also receiving more and more attention. At present, the more mature methods for preparing carbon nanotubes mainly include Arc Discharge, Laser Ablation, and Chemical Vapor Deposition. Among them, the chemical vapor deposition method has the advantages of high yield, strong controllability, compatibility with the integrated uranium integrated circuit process, and the like, which is convenient for industrial large-scale synthesis, and thus has been widely accepted in recent years. attention. Chemical vapor deposition methods for preparing carbon nanotubes generally include previous Thermal Chemical Vapor Deposition (CVD), piasma chemical Vapor Deposition (PCVD) and laser assisted Laser-Induced Chemical Vapor Deposition (LICVD). 6 200827475 Previous laser-assisted chemical vapor deposition methods generally used lasers as a fast heating source. The laser was directly exposed to the substrate required for growth to raise the temperature required to grow. When the carbon-containing reaction gas flows through the high-temperature base surface, the recording temperature rises, and by reacting with the catalyst on the substrate, the reaction gas generates scales or chemical reactions, thereby growing the carbon nanotubes. The growth of carbon nanotubes by laser-assisted chemical vapor deposition of the first month is usually performed using solid laser H or gas laser ||. The towel, the target laser includes, for example, a yttrium aluminum garnet (M:YAG) laser or an argon ion laser; the gas laser includes a carbon dioxide laser. The beam quality of the above-mentioned lasers is very good. However, the above-mentioned lasers are generally single-mode or multi-mode, and the above-mentioned lasers are generally bulky and environmentally demanding. Further, the above-mentioned lasers generally require a corresponding water cooling system and temperature control system, an expensive power source, and a good anti-vibration system and optical system. All of the above disadvantages will limit the growth of carbon nanotubes by laser assisted chemical vapor deposition using the above-described lasers to varying degrees. In addition, previous laser-assisted chemical vapor deposition using solid-state and gas lasers generally required to perform in a sealed reactor and to allow the reaction gas to fill the entire reaction space. The equipment was complicated and difficult to make large-scale The reactor is used to grow carbon nanotubes by chemical vapor deposition on a large-area substrate. Previous semiconductor lasers have the advantage of being small in size and low in cost relative to the solid and gas lasers described above. Specifically, the conventional semiconductor laser generally does not require a water cooling system, the ordinary heat sink can achieve heat dissipation, and does not require temperature control, and the device is simple and convenient to use. In addition, the previous half of the 200827475 conductor laser requires only a normal constant current power supply and does not require a good anti-shock system and optical system. However, previous laser-assisted chemical vapor deposition of carbon nanotubes did not use semiconductor lasers. It is indeed necessary to provide a method for laser-assisted chemical vapor deposition of carbon nanotube arrays using semiconductor lasers. SUMMARY OF THE INVENTION A method for preparing a carbon nanotube array includes the steps of: providing a substrate; forming a catalyst layer on a surface of the substrate; and introducing a mixed gas stream of a source gas and a carrier gas to the catalyst a layer surface; and providing a semiconductor laser system to emit a laser beam focused on the substrate to grow the carbon nanotube array. Compared with the prior art, the method for preparing a carbon nanotube array adopts a laser beam generated by a semiconductor laser to irradiate a growth carbon nanotube array, and the semiconductor laser has a small size, high coupling efficiency, and fast response speed. The wavelength and the size are matched with the size of the optical fiber, and can be directly modulated, and the coherence is good. The preparation method of the carbon nanotube array of the embodiment of the invention has the advantages of low cost and strong controllability. In addition, since the semiconductor laser has a shorter wavelength than the gas laser and the laser beam of the semiconductor laser is distributed in a square wave, it is more advantageous for the base and the catalyst to be heated at a constant speed. Moreover, since the carbon nanotube catalyst layer or the light absorbing layer is used, 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 thus is simple and controllable. [Embodiment] Hereinafter, the present invention will be further described in detail with reference to the accompanying drawings. Referring to FIG. 1, a method for preparing a carbon nanotube array according to an embodiment of the present invention mainly includes the following steps: Step 1: Providing a substrate. In this embodiment, the base material is made of a material resistant to southermost materials. According to different applications, the base material in this embodiment may also be selected from transparent or opaque materials, for example, when applied to semiconductor electronic devices, opaque materials such as tantalum, cerium oxide or metal materials may be selected; when applied to large-area flat panel displays In the case, a transparent material such as glass or a plastic organic material is preferable. Step 2: uniformly forming a catalyst layer on one surface of the substrate. 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, inscription, recording and alloy materials thereof may also be used. Further, the catalyst layer may oxidize the catalyst layer by high temperature annealing or the like to form catalyst oxide particles. Further, the catalyst layer of the embodiment of the present invention may alternatively form a carbon-containing catalyst layer or a light absorbing layer may be formed in advance between the catalyst layer and the substrate. When a catalyst layer for forming a carbon is used, the method for preparing the carbon-containing catalyst layer comprises the steps of: providing a mixture of a dispersant and a carbonaceous material, and mixing with a solvent to form a solution; and ultrasonically treating the solution. Dispersing; adding a metal nitrate mixture to the dispersed solution to obtain a catalyst solution; uniformly applying the 9200827475 catalyst solution to the surface of the substrate; baking the substrate coated with the catalyst bath to form a surface on the substrate A carbon-containing catalyst layer. Wherein, the carbonaceous material comprises a carbonaceous material such as carbon black or graphite. The dispersant is used to uniformly disperse the carbonaceous material, preferably sodium dodecyl Benzene Sulfonate (SDBS). The solvent can be selected from an ethanol solution or water. The mass ratio of the dispersing agent to the carbonaceous material is 1:2 to 1:10. In this embodiment, it is preferred to use 〇~100 mg of sodium dodecylbenzenesulfonate and 100 to 500 mg of carbon black mixture and ethanol solution. Mix to form a solution. The metal nitrate mixture includes magnesium nitrate (Mg(N〇3)2.6H2〇) and iron nitrate (Fe(N〇3)3.9H2〇), cobalt nitrate (Co(N〇3)2.6H2〇) or nickel nitrate A mixture of any one or several of (Ni(N〇3)2.6H2〇). In this embodiment, ferric nitrate (Fe(N〇3)3.9H2〇) and magnesium nitrate (Mg(N〇3)r6H2〇) are preferably added to the solution to form a catalyst solution, and the catalyst solution contains 〇·〇1~ 0.5 mol/L (Mol/L) of magnesium nitrate with 0·01~0·5 Mol/L of ferric nitrate. The baking temperature is 60 to 100 °C. The effect of baking is to evaporate the solvent in the catalyst solution to form a carbon-containing catalyst layer. In this embodiment, the carbon-containing catalyst layer has a thickness of 1 Å to 1 μm. The catalyst solution is applied to the surface of the substrate by spin coating. The rotation speed is 1000~5000 rpm, preferably 1500 rpm. When a catalyst is used to form a light-absorbing layer of 200827475 between the catalyst layer and the substrate. 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 the protective gas environment, the carbonaceous material is coated. The substrate is gradually heated to above about 300 ° C and blanched for a period of time; naturally cooled to room temperature to form a light absorbing layer on the surface of the substrate. In the embodiment of the invention, the shielding gas comprises nitrogen or an inert gas, and the carbonaceous material is preferably a graphite emulsion material which is currently widely used in electronic products such as cold cathode cathode tubes. Further, the graphite emulsion may be formed on the surface of the substrate by spin coating at a number of revolutions of 1 〇〇〇 5 01 0111, preferably 15 Å 111. 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 the organic matter in the graphite milk. Further, when a light absorbing layer is used, the catalyst layer may be formed by applying a catalyst solution to the light absorbing layer, and the specific steps thereof include: providing a catalyst ethanol solution; and applying the catalyst ethanol solution to the light absorbing agent Layer surface. In this embodiment, the catalyst ethanol solution is formed by mixing a metal nitrate mixture with an ethanol solution. The metal nitrate mixture is magnesium (Mg(N〇3)2, 6H2〇) and iron (Fe(N〇3)3.9H2〇), and tannic acid (Co(N〇3)2 · 6H2O Or a mixture of one or more of the lithic acid (Ni (Ν〇3) 2 · 6H2O). Preferably, the catalyst ethanol solution is an ethanol solution of a mixture of magnesium nitrate and ferric nitrate, and the content of the acid iron in the solution is 0.01~〇. 5Mol/L, the content of the stone acid is 11 200827475 0. 01~0 5Mol/L. 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 1,500 rpm. The thickness of the catalyst layer formed is from 1 to 100 nm. Step 3: 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 hydrocarbons such as decane, 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 post-source gas is 5:1 to 10:1, and this embodiment is preferably an argon gas of 200 standard cc/min (seem) and an acetylene of 25 sccm. Step 4: providing a semiconductor laser system to emit a laser beam to focus on the substrate to grow the carbon nanotube array. Referring to FIG. 2, the semiconductor laser system of the present embodiment includes a laser diode 12, a multimode fiber 14 connected to the laser diode 12, and a focusing lens 18. The laser diode 12 is coupled to one end of the multimode fiber 14 , and the laser beam 16 generated by the laser diode 12 is emitted through the other end of the multimode fiber 14 and is focused by the focusing lens 18 and then irradiated on the substrate 22 . on. In this embodiment, the multimode fiber 14 has a diameter of 20 to 100 micrometers. The output power of the laser diode 12 is 0 to 10 watts, and the resulting laser wave length is 700 to 1300 nm. Preferably, the output power of the laser diode 12 of the present embodiment is 2 watts, and the generated laser wavelength is preferably 808 奈 12 200827475 . After being coupled to the multimode fiber 14 and focused by the focusing lens 18, the laser beam 16 is irradiated onto the substrate 22 with a spot diameter of 50 to 2 0 〇 micrometers. # It can be understood that the focused laser beam 16 can be directly irradiated from the front surface on the surface of the catalyst layer of the substrate 22, or as shown in FIG. 2, when the substrate material is a transparent material or a thinner opaque material, the laser The beam 16 can also be focused and illuminated on the opposite side of the substrate 22. When the laser beam 16 is illuminated on the opposite side of the substrate 22, the laser beam 16 can be rapidly transmitted through the substrate 22 to the catalyst layer and heat the catalyst. After the reaction pre-tanning time, due to the action of the catalyst, and the laser beam is irradiated on the base catalyst layer to heat the catalyst, the carbon source gas introduced into the vicinity of the substrate is pyrolyzed into a carbon unit (c=c or c) at a certain temperature. hydrogen. Among them, hydrogen will reduce the oxidized catalyst, and the carbon will be adsorbed on the surface of the catalyst layer to grow a carbon nanotube. Further, in the present embodiment, the action of absorbing the laser ruthenium by the carbon-containing catalyst layer or the light absorbing layer is employed. The reaction temperature of the chemical vapor deposition method may be lower than 6 〇 0 ° C. Alternatively, the carbon-containing catalyst layer or the light-absorbing layer can release carbon atoms in the reaction to promote nucleation and growth of the carbon nanotubes. Since the embodiment of the present invention mainly utilizes the thermal effect of the laser, the optical effect of the laser is not high. Therefore, by coupling the laser diode 12 and the singular mode fiber 14 to generate multi-mode laser light, it is advantageous to uniformly heat the catalyst. Effectively increase the laser power. In addition, since the semiconductor laser has a shorter wavelength than the previous gas laser, and the semiconductor laser has a square wave distribution of the 200827475 laser beam, it is more advantageous for rapid heating of the substrate and the catalyst. In addition, since the embodiment of the present invention uses laser focus irradiation to grow the carbon nanotubes, the catalyst local temperature can be heated and absorbed enough energy in a short time. Meanwhile, the carbon source gas is directly passed to the heated Near the surface of the catalyst. Therefore, the embodiment of the present invention can ensure the desired temperature and the concentration of the carbon source gas in the vicinity of the catalyst for growing the carbon nanotube array without the need of a sealed reaction chamber, and the reduction of hydrogen gas due to the decomposition of the carbon source gas. The action ensures that the oxidized catalyst can be reduced and promotes the growth of the carbon nanotube array. Referring to FIG. 3, when the embodiment of the present invention uses a carbon-containing catalyst layer k' laser beam to vertically illuminate the glass substrate from the reverse side for about 5 seconds, a nanotube as shown in FIG. 3 can be obtained. Array.兮 The carbon nanotube array is in the shape of a hill and is perpendicular to the glass substrate. The carbon nanotube array has a diameter of 50 to 80 μm and a height of 1 〇 to 2 μm. Each carbon nanotube has a diameter of 40 to 80 nm. Referring to FIG. 4, when the graphite layer is used as the light absorbing layer in the embodiment of the present invention, the laser beam is vertically irradiated from the reverse surface to the catalyst of the glass substrate for about 3 seconds. A carbon nanotube array as shown in Fig. 4 can be obtained. The 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 μm and a height of 10 to 20 μm. Each carbon nanotube has a diameter of 10 to 30 nm. Further, in the laser assisted chemical vapor deposition method of the present embodiment, the 200827475 long carbon nanotube array can be irradiated onto the catalyst layer of the substrate by controlling the moving laser beam to realize the growth of nanocarbon on the large-area substrate. Tube 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 preparing a carbon nanotube array according to an embodiment of the present invention. Fig. 2 is a schematic view showing the structure of an apparatus used in a method for preparing a carbon nanotube array according to an embodiment of the present invention. Fig. 3 is a scanning electron micrograph of a carbon nanotube array pattern obtained by using a carbon-containing catalyst layer in an embodiment of the present invention. Fig. 4 is a scanning electron micrograph of a carbon nanotube array pattern obtained by using a light absorbing layer in an embodiment of the present invention. [Main component symbol description] None 15