标题: | 奈米碳管场发体在可挠性碳布上之成长及特性研究 Growth and Characterization of CNT Field Emitters on a Flexible Carbon Cloth |
作者: | 郑丞志 Cheng-Chih Cheng 吴宗信 Jong-Shinn Wu 机械工程学系 |
关键字: | 场发射;奈米碳管;可挠性;碳布;Field Emission;Carbon Nanotube;Flexible;Carbon Cloth |
公开日期: | 2007 |
摘要: | 奈米碳管场发射显示器是一种跟阴极射线管显示器比较薄的平面显示器。有较低的功率消耗,及预计成为下一个世代新且大的平面显示器。成长在碳布上的奈米碳管有较低的操作电场是由于碳布的编织几何分布。所以奈米碳管成长在可挠性碳布上在微电子工业有实际且方便的应用。在此篇论文中,我们比较利用化学气相沈积法成长在碳布上的催化剂奈米颗粒及奈米碳管,在不同的前处理及成长条件下,如前处理时间、温度、气体流量以及成长时的时间、温度、气体流量时的直径尺寸大小及场发射特性。在我们的实验里,成长过程使用乙烯当成制程气体,氢气及氮气为稀释或承载气体,镍为催化剂,钛及铝当缓冲层。实验结果显示,催化剂奈米颗粒的尺寸大小跟奈米碳管的直径大小相同而且大小尺寸差异满明显的,最大的碳管尺寸为160 nm,最小为12nm。根据此实验结果,可以藉由控制催化剂奈米颗粒的尺寸大小来形成想要的直径尺寸的奈米碳管。另外,我们也发现当我们加入铝当缓冲层时,形成在碳布上的催化剂奈米颗粒及奈米碳管尺寸比没有加入缓冲层及加入钛金属为大。因此,可以藉由加入不同的缓冲层来控制奈米碳管的直径尺寸。根据场发射的结果显示,场发特性跟不同的前处理及成长的参数有关。此篇论文中最佳的起始电压在时间30分钟、温度550℃、氢气流量100 sccm氮气流量500 sccm时为8.2 V/μm,此值远低于Jo, S. H et发表约0.34 V/μm。此差异可能是因为催化剂成长的不同,此论文是用热蒸镀的方式,Jo, S. H et是用溅镀的方式。 Carbon nanotube based field emission displays (CNT-FEDs) are generally described as devices for thin flat panel display compared with Cathode Ray Tube (CRT), having low power consumption and be expected to become new and large flat panel display in next generation. The lower operating electric field of carbon nanotubes grown on carbon cloth is due to geometrical configuration of woven nature of carbon cloth. So the carbon nanotubes grown on flexible carbon cloth has practical and convenient applications of microelectronics. In this thesis, we compare size and field emission characteristics of catalyst nano particle with carbon nanotube grown on carbon cloth under the various conditions, pretreated time, temperature, gas flux, and growth time, temperature and gas flux by thermal chemical vapor deposition. The growth process uses ethylene (C2H4) as the process gas, hydrogen (H2) and nitrogen (N2) as the carried/ diluted gas, nickel as catalyst and titanium (Ti), aluminum (Al) as buffer layers in our experiment. The experiment results reveal that the diameters of catalyst nano particle are the same as of carbon nanotube and the size difference of CNTs growth on carbon cloth is evident. The biggest size of CNT is about 160 nm, and the smallest size of CNT is 12 nm. According to the results, we can grow the diameter size of carbon nanotube that we want by controlled the size of catalyst nano particle. In addition, we also find that the catalyst nano particle and carbon nanotube formed on the carbon cloth with deposited nickel are larger than the titanium as buffer layer, but it is smaller than the aluminum as buffer layer. So we can control the diameter size of carbon nanotube by adding different buffer layer. According to the field emission results, it reveals that the emission characteristics are relation to various pretreated and growth parameters. The best turn on field of carbon nanortubes growth on carbon cloth in this thesis is near 8.2 V/μm in conditions, temperature: 550℃, H2 flux: 100 sccm, N2 flux: 500 sccm, time: 30 min, and is lower than results that Jo, S. H et. al. published in 2004. Maybe the difference is due to methods for catalyst deposited and type of catalyst. In this thesis, we deposited catalyst by using thermal evaporator, and it is by sputter deposition in that published. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT009514550 http://hdl.handle.net/11536/38539 |
显示于类别: | Thesis |