铁电阴极材料电子发射机理的实验研究

快极化反转在铁电阴极电子发射过程中具有决定性的作用,本工作采用ＸＲＤ,ＳＥＭ等方法铁电发射机理,ＸＲＤ图谱、胞参数测试结果以及扫描电镜观察到的电畴排列状况等从多个角度反映出不同铁电材料在前、后的晶体结构及电畴铁相应变化状况,对实验结果的分析有助于理解铁电阴极电子发射机理以及民组成、结构之间的关系。     

无铅阴极的相变致电子发射研究

研究了最新无铅阴极钛酸铋钠(Na1 2Bi1.2TiO3，NBT)基铁电陶瓷的电子发射性能和电子发射的机理。采用常规陶瓷工艺制备了发射阴极样品，并在阴极上施加高达15kV的激励脉冲，获得了20A／cm^2的最大发射电流密度。在施加激励电压的同时观察到3个发射电流脉冲峰值，该现象不同于其他的阴极。通过测试NBT基铁电陶瓷的相变性能，修正了得到公认的快极化反转致电子发射理论，提出相变致电子发射理论公式，合理解释了该新型无铅NBT基阴极的电子发射3个峰现象，说明了电子发射不仅可以由快极化反转产生，也可以由相变导致的极化变化产生。     

电子发射元件驱动方法、电子源驱动和制造方法及显示器

一种电子发射元件的驱动方法，在形成有由碳纤维集合体构成的电子发射体的阴极和与该阴极对向配置的对向电极之间施加电压，从所述电子发射体发射电子，其特征是：将驱动开始之前在所述阴极与所述对向电极之间施加的最大电压设定为最大施加电压Vmax,通过在所述阴极与所述对向电极之间施加比所述最大施加电压Vmax、小的驱动电压V来驱动所述电子发射元件。     

栅控纳米碳管冷阴极X线管

本发明涉及对现有X线管的工作原理结构材料及其供电电路的重大改进。其特征是由纳米碳管膜片作为X线管阴极电子发射体，在该膜片中心的发射面积上设置有纳米碳管阵列；在纳米碳管膜片相对应的位置上设置有栅极片，栅极片是固定在阴极组合体外壳上并与之相互导通，纳米碳管膜片与栅极片及阴极组合体外壳被绝缘垫片所隔离。     

高功函数金属Al作阴极的高效率白光聚合物电致发光

我们用聚电解质PFN做电子注入层,制备了高功函数金属Al做阴极的高效率白光聚合物电致发光。以蓝绿光发光中心的聚合物为主体和掺杂红光磷光染料,通过改变红磷光的掺杂浓度调节器件的电致发光光谱,得到白光发射。并研究了电子传输材料对WILLED器件发光光谱的影响。     

微生物燃料电池阴极系统的研究进展

微生物燃料电池,简称MFCs,其阴极系统通常由电极材料、催化剂、电子受体和阴极室等组成。MFCs阴极是电子受体进行还原反应的场所,是影响MFCs性能的重要因素,决定了反应器的经济性和持久性。文章根据MFCs阴极系统的构造,综述了阴极的材料、催化剂、电子受体以及构型在国内外的最新研究进展,指出了当前MFCs阴极设计存在的问题和今后MFCs研究努力的方向。     

电子陶瓷材料及产品与技术解读

电子陶瓷在信息的检测、转化、处理和存储显示中应用广泛,是信息技术中基础元器件的关键材料。针对电子陶瓷材料的功用特点及应用领域,分别介绍了电子绝缘装置陶瓷,电子电容器陶瓷,电子铁电陶瓷和半导体陶瓷以及电子快离子陶瓷的结构原理、性能优势和制造工艺等,同时指出了电子陶瓷材料的发展前景。     

催化生成的碳纤维场致发射体和由此制得的场致发射体阴极

本发明提供一种包括在金属小颗粒上由含碳气体催化分解所生成的碳纤维的电子场致发射体和场致发射体阴极。每根碳纤维都有石墨烯片晶(graphene platelets)，石墨烯片晶相对于纤维轴以一个角度排列以便碳纤维的周边基本上由石墨烯片晶的边缘组成。这些场致发射体和场致发射体阴极可用于电脑、电视和其它种平板显示器中。     

制取六硼化镧的试验报告

一、引言六硼化镧(L_aB_6)熔点高,硬度大,化学性稳定,并具有电子逸出功小,抗中毒性强,电流密度大,寿命长等优点,是一种很好的阴极发射材料。其主要性质列于表1。在回旋加速器的离子源中用L_aB_6代替T_a作阴极时,使用寿命可由原来的12小时提高到150—180小时。此阴极有高的功率,可用于磁控管,质谱仪和电子显微镜中,也可用在电子束焊接和电子轰击炉上。随着社会主义事业的飞速发展,我国有不少单位急需使用L_aB_(60)为了确定一个经济     

微生物电解池辅助CO2甲烷化阴极材料的研究进展

微生物电解池（microbial electrolysis cell,MEC）产甲烷技术是一种有望成为缓解能源危机与温室效应的重要新型途径。它以外界输入的较小电能为能量来源,以微生物为催化剂,在阳极通过分解有机物形成电子和质子;在阴极产生氢气和甲烷。近年来,MEC在反应器构型、阴极材料设计及电子转移途径、微生物群落结构组成等方面的研究取得了重要进展,寻找高效低价的阴极材料催化剂,实现MEC从概念到应用成为相关领域的研究热点。本文综述了MEC耦合厌氧消化系统产甲烷的工作原理和常见阴极材料的发展现状;分别对碳基阴极、金属基阴极及复合阴极的甲烷产率进行了阐述;系统介绍了不同阴极系统的电子传递方式、电化学特性、生物相容性、微生物群落结构组成等属性;讨论了各类电极的优缺点,并指出了今后的重点研究方向,以期为MEC耦合厌氧消化产甲烷技术的工程应用提供基础。     

Study on the characteristics of ferroelectric electron emission

Electron emission from ferroelectric cathodes is commonly suggested as an electron source for different applications due to its special characteristics such as high current density, easy treatment and operation. In this experimental research, the electron emission properties of ferroelectric cathodes made of lanthanum-doped lead zirconate–titanate (PLZT) ceramic are studied. The electron beam spot shape was recorded via proximity-imaging techniques.     

Superior integrated field emission cathode with ultralow turn-on field and high stability based on SiC nanocone arrays

Low turn-on field (E_to) and stable electron emission are two of key parameters for reliable application of field emission (FE) cathodes. In the present work, we developed a novel high-performance integrated field emission cathode based on well-aligned SiC nanocone arrays via an electrochemical etching approach. The etched SiC nanocone emitters and the underlying remaining SiC wafer are designed into a single-crystalline integrated architecture without interfaces, which favors cathodes with a sturdy configuration to resist Joule heat during long period electron emission process and structural failure caused by the existed strong electrostatic forces. Accordingly, the E_to of the integrated SiC cathode is reduced to 0.32 V/μm, which is the lowest value among all the previously reported SiC nanostructured emitters. In addition, the integrated cathode presented superior stability with an electron emission fluctuation of 3.3% over 10 h. This work provides a new perspective for designing and fabricating advanced FE cathodes for further promising applications in harsh working conditions with high performance.     

Polarization Switching of and Electron Emission from Lead Lanthanum Zirconate Titanate Ceramics

This paper focuses on understanding the influence of ma-terial properties on the complicated ferroelectric (FE) emis-sion process. Three different compositions in the lead lan-thanum zirconate titanate (PLZT) system were chosen for study, based on their widely different dielectric and ferro-electric properties: antiferroelectric (AFE) 2/95/5, "nor-mal" ferroelectric 8/65/35, and nonferroelectric 15/65/35. Repeatable emission was obtained from the 2/95/5 compo-sition, which could also be modulated at high frequency (200 kHz). The fast AFE ⇆ FE phase transition is respon-sible for the FE emission properties of this material, which is supported by the relationship between the switching cur-rent and the emission current. Comparatively, FE emission from the 8/65/35 composition degraded rapidly, which was attributed to decreases in the remanent polarization. No emission signal was detected from the 15/65/35 composi-tion, because no switching activity occurs, which can be interpreted as additional evidence that electron emission from the previously mentioned two compositions was in-deed a FE emission process.     

Si field emitter arrays coated with thin ferroelectric films

This paper demonstrates novel approach on Si field emitter arrays (FEAs) coated with thin ferroelectric films for vacuum microelectronic applications, which exhibit enhanced electron emission behaviors. The films were deposited using sol–gel and sputtering process, respectively. In sol–gel approach, the emission behavior is highly correlated to the crystallinity of (Ba,Sr)TiO₃ (BST) layer. The interfacial reaction between Si and BST film would deteriorate the crystallinity of the films, and in turn impede the electron emission from silicon tips. The film thickness and the dopants also affect the emission behaviors significantly. In sputtering process, the nitrogen-incorporated SrTiO₃ (STO) films are deposited with eliminated interfacial due to relatively lower processing temperature. The enhanced emission characteristics are highly correlated with nitrogen-incorporation and film thickness. These encouraging results have offered great promise for the application of ferroelectric films in field emission devices.     

Carbon nanowalls on graphite for cold cathode applications

We demonstrate for the first time high performance carbon nanowall coated graphite cold cathodes. These graphite cold cathodes are capable of emitting high electron current density under low DC electric fields at room temperature. Carbon nanowalls with nanometer scale sharp edges are grown on graphite plates by means of DC plasma enhanced chemical vapor deposition in a gas mixture of methane and hydrogen. High performance cold cathodes are evaluated by means of measuring the electron field emission current density versus applied electric field (J–E), and examining the nano-graphite structures by SEM and Raman spectroscopy. Graphite is light weight, of high electrical and thermal conductivities, and chemically inert. It is expected that high performance and low cost graphite cold cathodes will find a broad spectrum of scientific and practical applications.     

Electron emission from Pb0.88La0.08(Zr0.65Ti0.35)O3 ferroelectric ceramics

The electron emission characteristics of PLZT 8/65/35 ferroelectric are studied. High current density has been obtained from PLZT 8/65/35 ferroelectric cathode. The source of the disturbance in the experiment is discussed and several methods to reduce the disturbance are proposed. It is discovered that there is a voltage threshold, and the electron emission will not occur until the amplitude of the pulse exceeds the threshold. Moreover, there are two current peaks in the FE electron emission curves, the primary peak remains stable in location and intensity, while the secondary one shows instability during repeating experiments.     

Investigation on the Plasma-Induced Emission Properties of Large Area Carbon Nanotube Array Cathodes with Different Morphologies

Large area well-aligned carbon nanotube (CNT) arrays with different morphologies were synthesized by using a chemical vapor deposition. The plasma-induced emission properties of CNT array cathodes with different morphologies were investigated. The ratio of CNT height to CNT-to-CNT distance has considerable effects on their plasma-induced emission properties. As the ratio increases, emission currents of CNT array cathodes decrease due to screening effects. Under the pulse electric field of about 6 V/μm, high-intensity electron beams of 170–180 A/cm² were emitted from the surface plasma. The production mechanism of the high-intensity electron beams emitted from the CNT arrays was plasma-induced emission. Moreover, the distribution of the electron beams was in situ characterized by the light emission from the surface plasma.     

High-current electron emission characteristics of cathodes based on diamond films

Using different gas source, four types of diamond thin films were prepared on silicon substrate by microwave plasma chemical vapor deposition (MPCVD) technology, and characterized in detail through scanning electron microscopy (SEM), Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. High-current pulsed emission characteristics, tested with a 2 MeV line-inducing injector, showed that all of CVD diamond films had high emission current density (> 70 A/cm²) and [100] textured B-doped microcrystalline diamond film possessed the largest emission current density of 115.1 A/cm². No obvious bright light and luminescent zones from side view CCD images indicated a possible pure field-emission mechanism of these diamond cathodes. Simultaneously, large decrease in the electron emission capability, above 15%, could be observed after several pulsed measurements, but this decrease could be completely recovered through the treatment of surface re-hydrogenation for emitted diamond cathodes, suggesting that emission performance of CVD diamond cathodes was closely relevant to hydrogen coverage ratio. The present data indicated that as-deposited CVD diamond films could be a potential candidate as cold cathode for the application in high-current electron emission field.