后栅极场致发射显示板制作的研究

介绍了具有广阔应用前景的平板显示器件——场致发射显示板及其优良的显示性能。三极结构具有低压调制的优点，而后栅极场致发射显示板更具有结构简单、发射均匀性好的优势。采用丝网印刷工艺成功地制作了后栅极场致发射显示板，利用碳纳米管作为阴极材料，并对介质层厚度对器件的影响、老炼、发光均匀性等问题进行了探讨。     

平板显示用场发射冷阴极材料

简要介绍了场致发射显示器件的结构和原理,全面总结了人们正在研究的各种场发射冷阴极材料,其中主要包括金属场致发射阵列、硅场致发射阵列、金刚石及其相关薄膜、碳纳米管和纳米纤维、一维纳米材料、碳化物、氮化物薄膜等.并展望了场致发射显示器件的发展前景.     

常开型后栅极场致发射显示板工作特性的研究

常开型后栅极场致发射显示板是一种新型的场致发射器件.它直接利用阳极使阴极产生场致电子发射,而通过埋在阴极之下的栅极上施加负电压来阻止阴极产生场致电子发射来调制显示所需的图像.为了研究该场致发射显示板的阴极发射特性,本文采用有限元法对场致发射区域内的电场分布进行了模拟计算,用Fowler-Nordheim(F-N)公式计算了阴极表面的发射情况.并研究了阳极电压、阴极电压、阴调距、阴极宽度和阴极厚度等参数的改变对阴极发射特性和栅极调制能力的影响.计算结果显示阴极发射特性和栅极调制能力与上述电参数和结构参数关系密切,从而为优化设计这种显示器件提供了方向.     

新型碳纳米管场致发射显示驱动电路的研究

采用碳纳米管作为发射源的场致发射显示器是一种新型的平板显示技术,文章研究一种碳纳米管场致发射显示器件的驱动方法。该方法灰度等级实现方法简单,大大降低了扫描电极频率,有效地解决了高压和高速度之间的矛盾,能够满足用丝网印刷制备碳纳米管阴极的场致发射显示器件驱动电压高的要求。     

平栅极氧化锌场致发射电子源的制备及性能研究

采用传统的光刻技术制备平栅极场致发射阴极阵列,利用水热法原位合成ZnO发射源,并组装成平栅极ZnO场致发射电子源;利用光学显微镜、SEM和XRD表征其微观结构,分析ZnO发射源的生长机制,并结合场发射测试系统研究其发射特性。结果表明,ZnO发射源是平均直径为300nm的六方纤锌矿氧化锌纳米棒,且沉积在平栅极场致发射阴极阵列的阴极电极表面。场发射测试表明,平栅极ZnO场致发射电子源的发射特性完全由栅极控制。当阳极电压为2000V,器件的开启电压为150V;当栅极电压为275V时,发射电流可达345μA;在栅极电压为260V时,器件的发射电流波动范围为±5.5%左右,发光亮度高达750cd/m~2,表明该器件具有较好的场发射特性。     

场致发射阴极材料的研究进展

场致发射显示是一种具有良好应用前景的新型显示技术,场致发射阴极材料是场致发射显示器的核心内容.综述了近年来场致发射材料的研发热点,对金属、硅、金刚石及类金刚石薄膜、GaAs和CaN等场致发射材料的研究做了简要的归纳,同时介绍了碳纳米管、表面传导型场致发射材料及采用定向凝固技术制备的Si-TaSi2共晶自生复合场致发射材料等新型场致发射材料的研究进展,并展望了场致发射材料的研究及应用前景.     

场致发射电子源的应用及其研究进展

由于具有低温、电子瞬间发射等优势,场致发射电子源在X射线管、负氢离子源、显示器件等领域都具有应用潜力。本文首先介绍了场致发射的几种应用;比较分析了不同场致发射电子源及其特点;最后结合实验研究工作,分析了类金刚石膜作为场致发射阴极材料的可行性。分析可知:Spindt加工困难且易于损坏;碳纳米管以其独特的结构成为目前研究最热的材料;类金刚石膜易于合成、成份可调节,它兼具的金刚石和石墨的优点使其成为一种潜在的理想场致发射阴极材料。     

碳纳米管场致发射显示器的研究进展

碳纳米管场致发射显示器(CNT-FED)具有驱动电压低、功耗小和制造成本低廉等优势,有望成为下一代平板显示器件的主流产品.全面系统地分析了制约CNT-FED商品化进程中的关键技术:碳纳米管定向可控生长、阴极低的开启场、高的电流发射密度、大面积发射均匀性、长寿命稳定发射以及低成本制造工艺等的研究进展,结合我们的课题研究与国内外现状,提出了实现碳纳米管场致发射显示器产业化的发展方向与研究途径.     

基于二次电子发射的FED中支撑结构的优化设计

基于二次电子发射的场致发射显示器(HOPFED)是一种新型的场致发射器件.其新颖之处在于其独特的支撑形状,这种结构的优点是充分提高了场致发射显示的性能,如对比度、色纯及像素内的发光均匀性,并减少了离子轰击发射源.在目前已有的结构中,环形的屏上光点不能使荧光粉得到充分的利用,而且光点尺寸较小,容易使荧光粉达到饱和.为了得到符合荧光粉要求的光点形状,本文提出了diabolo形状flu支撑、ZEUs形状hop支撑以及长flu支撑三种支撑形状,并采用数值计算的方法对这几种不同的支撑结构对屏上光点的影响进行了模拟计算.计算结果表明,对这三种不同的支撑形状进行优化以后都能得到符合荧光粉的要求的屏上光点.在现有的工艺条件下,长flu支撑是一种能改善光点和场强分布,而又易于制作的支撑结构.     

前栅极碳纳米管场发射显示板关键结构参数的研究

前栅极碳纳米管场发射显示板是一种常用的场致发射器件。该器件通过栅极与阴极之间形成的电场产生场致发射电子,在阳极高压的作用下,电子从电场中获得能量,轰击荧光粉产生可见光。本文采用模拟计算的方法研究了标准结构场发射区域内的电场分布、阴极表面的发射情况、电子轨迹和着屏束斑。并研究了关键结构参数在公差范围内变化对阴极发射特性和阳极着屏束斑的影响。计算结果显示,阴极发射状况和阳极束斑对结构参数的变化非常敏感,也证明了前栅极结构对工艺要求十分严格。     

A study of emitter formation by various etching techniques and its application to flat panel display

Abstract

In view of the potential advantages of using field‐emission cathodes as electron sources, a renewed interest in advanced IC technology utilizing silicon‐based coldcathode microelectronics is emerging. However, some etching results concerning emitter formation are still unknown. This paper presents a study of emitter formation by various wet and dry etching methods. Some geometrical models are given for the analysis of anisotropic etching results. The emission features from different emitter arrays are also given for comparison. Through understanding the emission characteristics of various emitter arrays, a novel design for Field‐Emission Flat Panel Display is proposed.     

Effect of imidazolium phosphate and multiwalled carbon nanotubes on thermal stability and flame retardancy of polylactide

A series of composites based on polylactide (PLA), have been prepared by melt-blending with multiwalled carbon nanotubes (MWNT) and Tri(1-hydroxyethyl-3-methylimidazolium chloride) phosphate (IP) functionalized MWNT (MIP). The morphology, thermal stability and burning behavior of the composites were investigated by Field Emission Scanning Electron Microscopy (FESEM), Thermogravimetric Analysis (TGA) and Cone Calorimeter Test (CCT), respectively. Significant improvement in fire retardant performance was observed for the PLA/MIP composite from CCT (reducing both the heat release rate and the total heat release) and TGA (increasing the char residue) compared to PLA/MWNT. SEM and Raman spectroscopy were utilized to explore the surface morphology and chemical structure of the char residues. It revealed that the catalytic charring effect of IP, the physical crosslinking effect of MWNT, and the combined effect of both IP and MWNT (forming continuous and compact char layers) were very efficient in improving the flame retarding properties of PLA/MIP composite.     

Synthesis of vertically aligned carbon nanotubes using natural palm oil as carbon precursor

Vertically aligned carbon nanotubes (VACNTs) have been synthesized on silicon substrates in a thermal catalytic chemical vapor reactor using natural palm oil as the carbon source. Field Emission Scanning Electron Microscopy (FESEM) and microraman analysis revealed dense bundles of mixed multi-walled and single-walled carbon nanotubes (CNTs). The diameters of the single-walled carbon nanotubes (SWCNTs) were estimated to be between 0.6 nm and 1.2 nm. Thermogravimetric analysis (TGA) results showed that 90% purity was achieved at the expense of 4% weight catalyst material.     

Electrochemical characteristics of coated steel with poly(N-methyl pyrrole) synthesized in presence of ZnO nanoparticles

Poly(N-methyl pyrrole) (PMPy) coating was electrodeposited on steel substrates in mixed electrolytes of dodecyl benzene sulphonic acid with oxalic acid in the absence and the presence of ZnO nanoparticles (NPs). The morphology and compositions were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy and Energy-dispersive X-ray spectroscopy. Electrode/coating/electrolyte system was studied by Electrochemical Impedance Spectroscopy. The comparison between the pore resistance (R_po) of synthesized PMPy in the absence and presence of ZnO NPs indicated that the existence of ZnO increased the R_po of the coating. The FESEM micrographs indicated that the size of micro-spherical grains in the morphology of PMPy is significantly reduced and the surface area of PMPy is increased with the presence of ZnO NPs. The increase of the ability to interact with the ions liberated during the corrosion reaction of steel and the increase of the rate probability for the occurrence of cathodic reduction of oxygen on the PMPy with the increase of the surface area can be considered as reasons for improvement of protective properties of synthesized PMPy in the presence of ZnO NPs.     

Properties of titania/hydroxyapatite nanostructured coating produced by gas tunnel type plasma spraying

Anatase phase titanium dioxide has a photo-catalytic performance for environmental protection. In this study, titanium dioxide/hydroxyapatite photo-catalytic coating was deposited by gas tunnel type plasma spraying using powders with nano-sized grains. The porous structure coating with high photo-catalytic activity could be prepared to vary the injecting position of powder. The phase compositions and microstructures of the coating were characterized using X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM), etc. The results showed that the porous structure coatings with relatively high anatase content could be obtained by controlling the injecting position of the powder. The bimodal microstructure of the coatings was also controllable.     

Nickel oxide thin films by spray pyrolysis

The preparative parameters have been optimized for NiO film formation in fabricated Spray Pyrolysis System using pneumatic air pressure driven aerosol formation. The structural studies by X-ray diffractometer (XRD) have been carried out to investigate crystallographic features. It was revealed that NiO crystallizes in cubic bunsenite structure. The optical band gap for direct transitions was found to be equal to 3.67 eV. Field Emission Scanning Electron Micrographs (FESEM) have been employed to study morphological aspects of the prepared films. The elemental depth profiles of film contents have been obtained Auger Electron Spectroscopic (AES) studies.     

镜面塑料模具失效表面的缺陷分析

针对1.2083镜面塑料模具在抛光过程中出现的表面疤状凸起缺陷进行了系统分析.综合运用光学显微镜、场发射扫描显微镜等分析技术对表面缺陷的形貌、组织、微区成分及其与非金属夹杂之间的联系进行研究,同时分别对失效模具产品和金相试样的表面粗糙度进行了对比测量.结果表明,由于该模具钢材内部多种非金属夹杂物的存在以及局部成分不均等因素,导致模具在抛光过程中基体的连续性遭到破坏,从而引起产品表面出现肉眼可见的疤状凸起缺陷,导致模具失效.     

Enhanced electrochemical oxidation of methanol on copper electrodes modified by electrocorrosion and electrodeposition

In this paper, we report a study of electrocatalytic oxidation of methanol on copper electrodes subjected to different surface treatments, either electrocorrosion or electrodeposition in the absence of strong hydrogen co-deposition. The surface morphology of treated electrodes was examined by Field Emission Scanning Electron Microscopy (FE-SEM). The effect of different treatment conditions and the methanol concentration dependence were evaluated by cyclic voltammetric technique. The results indicate that the oxidation of methanol can be enhanced by a suitable micro and nano structure generated by these treatments. This enhanced electrode activity is related to an increase of the effective surface area and/or to an increase of the surface concentration of electroactive molecules or intermediates.