碳纳米管冷阴极制备方法及特性的研究

发布时间：2018-03-12 15:21

本文选题：碳纳米管　切入点：等离子体气相沉积法　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳纳米管(CNT)作为制备场发射冷阴极的理想材料,具有化学性质稳定、场发射电流密度大等优点,碳纳米管冷阴极有一个重要的用途就是可以用于高功率微波管的电子源。本文分别利用等离子体气相沉积法、丝网印刷法以及电泳沉积法这三种方法制备得到碳纳米管冷阴极样品,并利用场发射测试仪器测试每种碳纳米管冷阴极样品的场发射性能,并对场发射测试结果进行分析研究。本文利用等离子体气相沉积法(PECVD法)制备得到碳纳米管冷阴极样品。首先我们采用电泳沉积以及电子束蒸镀两种方法在衬底上镀覆铁催化剂颗粒层,然后利用扫描电子显微镜以及拉曼光谱对PECVD方法制备得到的碳纳米管冷阴极样品的表面形貌以及碳纳米管的缺陷程度进行表征。通过对比SEM照片发现采用电子束蒸镀法镀铁生长出的CNT的均匀性要远远优于电泳沉积法镀铁生长出的CNT。通过对比场发射测试结果发现碳纳米管的生长时间对其场发射性能也有着很大的影响。最终我们利用PECVD方法在碳纳米管的生长时间控制在20min的条件下制备得到碳纳米管冷阴极样品的最大场发射电流密度达到141mA/cm2,开启场强为1.2V/μm,阈值场强为3.8V/μm,场致发射区域的直径为3mm。本文还利用了丝网印刷法和电泳沉积法在Si片上面制备得到具有大面积发射区域的碳纳米管冷阴极样品,由于这两种方法属于移植法,相比PECVD这种直接生长法制备得到的碳纳米管冷阴极样品而言,其场发射电流密度较小,但具有成本较低、工艺简单等优点而且场致发射面积能够达到10mm×10mm。在利用丝网印刷法制备碳纳米管冷阴极样品时,我们研究了不同球磨时间、不同的有机浆料配比对制备得到的碳纳米管冷阴极样品的场发射性能的影响并分析其原因,最终我们利用丝网印刷法在球磨时间为2h、有机浆料配比为5:1:50的条件下制备得到碳纳米管冷阴极样品的最大电流密度达到2.8mA/cm2,开启场强为1.5V/μm。在利用电泳沉积法制备碳纳米管冷阴极样品时,我们研究了不同的电泳时间对制备得到的碳纳米管冷阴极样品的场发射性能的影响并分析其原因,最终我们利用电泳沉积法在磁控溅射Ti膜的Si片上面电泳沉积10min的条件下制备得到碳纳米管冷阴极样品的最大电流密度达到2.5 mA/cm2,开启场强为1.3V/μm。
[Abstract]:As an ideal material for preparing field emission cold cathode, CNT has the advantages of stable chemical properties and high field emission current density. One important application of carbon nanotube cold cathode is that it can be used as an electron source for high power microwave tube. The cold cathode samples of carbon nanotubes were prepared by screen printing and electrophoretic deposition, and the field emission properties of each kind of carbon nanotubes cold cathode samples were tested by field emission test instrument. In this paper, the cold cathode samples of carbon nanotubes were prepared by plasma vapor deposition (PECVD). Firstly, we used electrophoretic deposition and electron beam evaporation on the substrate. Coated with iron catalyst particle layer, Then the surface morphology and defect degree of carbon nanotubes (CNTs) prepared by PECVD were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The electron beam was found by comparing SEM photos. The uniformity of CNT grown by evaporation deposition is much better than that grown by electrophoretic deposition. The results of field emission test show that the growth time of carbon nanotubes has a great influence on the field emission properties of carbon nanotubes. The maximum field emission current density of carbon nanotube cold cathode samples prepared by PECVD method is 141mA / cm ~ 2, the opening field intensity is 1.2V / 渭 m, the threshold field intensity is 3.8V / 渭 m, and the field emission region is obtained by controlling the growth time of carbon nanotubes at 20min. The maximum field emission current density of carbon nanotube cold cathode samples is 141mA / cm ~ 2, and the threshold field intensity is 3.8V / 渭 m. Using screen printing and electrophoretic deposition methods to prepare carbon nanotube cold cathode samples with large emission region on Si wafer. Because these two methods belong to the transplantation method, compared with the carbon nanotube cold cathode sample prepared by PECVD, the field emission current density is lower, but the cost is lower. The process is simple and the field emission area can reach 10mm 脳 10mm. in the preparation of carbon nanotube cold cathode samples by silk-screen printing, we have studied different milling time. The effects of different organic slurry ratios on the field emission properties of the prepared carbon nanotube cold cathode samples were analyzed. Finally, we use screen printing method to prepare carbon nanotube cold cathode sample under the condition of milling time of 2 h and organic slurry ratio of 5: 1: 50. The maximum current density of carbon nanotube cold cathode sample is 2.8 Ma / cm ~ 2 and the open field strength is 1.5 V / 渭 m. Carbon is prepared by electrophoretic deposition method. When the nanotube cold cathode sample, We studied the effect of different electrophoretic time on the field emission properties of the prepared carbon nanotube cold cathode samples and analyzed the reasons. Finally, we prepared the carbon nanotube cold cathode samples by electrophoretic deposition under the condition of 10 min electrophoretic deposition on the Si substrate of magnetron sputtering Ti film. The maximum current density and the opening field intensity of the cold cathode samples are 2.5 Ma / cm 2 and 1.3 V / 渭 m respectively.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11;TB383.1

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