以常壓式化學氣相沉積法成長奈米碳管及其場發射特性之研究

Study of Carbon Nanotubes Grown by APCVD and the Field Emission Property

陳鴻欣(Hung-hsin CHEN)

指導教授 ： 溫武義

中原大學/工學院/電子工程研究所/碩士(2008年)

https://doi.org/10.6840/cycu200900359

摘要

自從奈米碳管在1991年被Iijima博士發現後，即廣泛得受到了科學家的注目。由於碳管有許多優越的特性，如：高導熱性、相當大的寬高比以及高楊氏係數…等，因此應用範圍也相當廣泛。到目前為止已有相當多種合成奈米碳管的方式。本篇論文中，以常壓式化學氣相沉積法在矽基板上選擇性成長高品質之奈米碳管陣列。首先，將基板選擇性蒸鍍上催化金屬鎳並以氨氣對於基板做前處理，接著通入碳源氣體乙炔進行碳管的成長，實驗溫度固定在800度而乘載氣體為氮氣。對於前處理之時間及氨氣流量，反應氣體氨氣與乙炔之流量比以及成長時間對於所成長出之奈米碳管之品質皆有所分析。此外，利用雙極式結構進行場發射特性量測。當碳管之長度增長時所需要的電場也就越低。使用長度為18 μm之碳管陣列時得到最低之起始電場 2 V/μm，其電流密度為10 μA/cm2，而臨界電場為3.26 V/μm，其電流密度為10 mA/cm2。本研究得到的結論是利用常壓式化學氣相沉積法獲得了高品質之碳管，該材料顯示了低電場之場發射特性。

關鍵字

奈米碳管 ； 化學氣相沉積 ； 場發射

並列摘要

Since carbon nanotube (CNT) was first discovered by Iijima
in 1991, it has attracted much attention due to its unique properties, for example: high thermal conductivity、high aspect ratio and high Young’s modulus. These properties can extend the application field of CNT to different devices. So far, there have been a number of studies on the growth of CNT by different methods. In this study, selective growth of well-aligned good-quality CNT array was grown on silicon substrate by atmospheric pressure chemical vapor deposition (APCVD). First, the patterned substrate was pretreated with NH3 and then CNTs were synthesized at 800 C using Ni as the catalyst, acetylene (C2H2) as the carbon source material and N2 as the carrier gas. Effects of the NH3-pretreatment, the flow ratio of [C2H2]/[NH3], and the CNT growth time on the qualities of CNT array were analyzed in detail. Furthermore, the field emission property of CNT array was investigated using a diode structure. It was found that the turn-on electric field decreased with increasing CNT length. The turn-on electric field as low as about 2 V/μm with an emission current density of 10 μA/cm2 was achieved for a CNT-array diode with the tube length near 18 μm. For the same device, the emission current density could be elevated to 10 mA/cm2 with the applied voltage of 3.26 V/μm. In conclusion, the good quality and well-aligned carbon nanotubes and the low
threshold electric field have been achieved.

並列關鍵字

chemical vapor deposition ； field emission ； Carbon nanotube

參考文獻

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