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碳纳米管场发射显示器的研究进展 总被引:14,自引:6,他引:8
碳纳米管因具有良好的电子发射特性而成为理想的场发射阴极材料,利用碳纳米管作阴极的场致发射平板显示器件的研究是目前显示技术领域的研究热点之一。报道了场发射显示器(FED)的结构及工作原理、阴极发射材料应具有的特点及碳纳米管在场发射领域中的应用情况。详细地论述了碳纳米管的场致发射特性,包括开启电场、发射电流密度、电流稳定性及发射点密度等,对国内外碳纳米管场发射显示器的发展现状及趋势作了回顾和展望,并对目前所面临的主要问题作了分析,同时提出了一些改进的思路。 相似文献
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在强电场条件下,由阴极通过场致发射产生的电子具有很强的空间电荷效应,因此真空二极管的空间电荷限制电流是设计高功率微波源等强流电子束器件时需要考虑的重要参数.场致发射电流密度只和阴极材料、阴极表面电场等有关,而空间电荷效应则会受二极管电压、间隙距离等因素的影响.为研究二极管间隙距离对场致发射过程中空间电荷效应的影响,建立了由场致发射阴极构成的一维平板真空二极管物理模型,利用第一性原理的粒子模拟方法,研究了二极管间隙距离和外加电压等参数变化时的阴极表面电场随时间的演变特性,得到了阴极表面稳态电场和二极管间隙距离之间的关系.结果表明,场致发射过程开始后,阴极表面电场先有个振荡过程,随后趋于稳定;在同一外加电场条件下,间隙距离越长,稳态电场的绝对值越小,且达到稳态所需的时间也越长;间隙距离越短,当阴极表面电场达到稳定状态时,二极管间隙区的电场分布变化越剧烈. 相似文献
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采用质点网格法(particle-in-cell),利用MAGIC软件模拟了场致发射的物理过程.对两 种典型的场致发射模型(Spindt阴极发射体和金刚石薄膜发射体)分别进行了模拟.对Spind t阴极发射,研究了发射特性与尖端尺寸,尖端与栅极面的相对高度的关系.对金刚石薄膜发 射,比较了三极管和四极管的发射特性,以及薄膜面积对发射特性的影响,得出金刚石薄膜 发射体优于Spindt发射体的特性.
关键词:
场致发射
MAGIC程序
Spindt发射体
金刚石薄膜发射体 相似文献
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生长温度对纳米氧化锌场发射性能的影响 总被引:1,自引:1,他引:0
采用锌粉和银粉为蒸发源,用热蒸发法不同温度下制备了四针状纳米氧化锌,并以单独的锌粉做对照。采用扫描电子显微镜(SEM)观察其形貌,X射线衍射(XRD)谱表征其晶体结构。采用丝网印刷方法将其制备为场致电子发射阴极,将阴极与印刷有荧光粉的阳极板组装成二极结构场致发射显示屏,并进行了场致电子发射特性对比实验。结果表明较高温度制备的氧化锌具有较好的场致发射性能;掺杂银粉的蒸发源制备的样品的发射性能明显优于没有掺杂银粉的样品。实验证明ZnO是一种优良的场致发射冷阴极材料,在真空电子方面具有广阔的应用前景。 相似文献
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四针氧化锌制备及其场致发射特性 总被引:1,自引:1,他引:0
采用了VS(Vapor-Solid)的方法制备了四针状ZnO,以此作为场致电子发射的冷阴极材料。并对材料进行了扫描电镜(SEM)和X射线粉末衍射(XRD)测试分析,揭示其表面形态和晶体结构。同时将阴极与印刷有荧光粉的阳极板组装成二极管结构场致发射显示屏,并进行了场致发射特性实验。该二极管结构的开启电压为3.6V/μm,其阈值电压为6.6V/μm,相应的电流密度为0.2mA/cm2,并且具有稳定的电流密度和均匀的显示效果。实验证明ZnO是一种优良的场致发射冷阴极材料,具有广阔的应用前景。 相似文献
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An improved planar-gate triode with carbon nanotubes (CNTs) field emitters has been successfully fabricated by conventional photolithography, screen printing and electrophoretic deposition (EPD). In this structure, cathode electrodes and ITO arrays linked with gate electrodes were interdigitated and paralleled on the same plane although the gate electrodes and cathode electrodes were isolated by dielectric layer, a so-called improved planar-gate triode structure. An electrophoretic process was developed to selectively deposit CNTs field emitters onto cathode electrodes in the CNTs suspension by an applied voltage between the gate electrodes and cathode electrodes. The optical microscopy and FESEM image showed that the CNTs emitters with the uniform packing density were selectively defined onto the cathode electrodes. In addition, field emission characteristics of an improved planar-gate triode with CNTs field emitters were investigated. The experiment results indicated that the turn-on voltage of this triode structure at current density of 1 μA/cm2 was approximately 55 V. The anode current and gate current came to 396 μA and 325 μA, at gate voltage and anode voltage of 100 V and 4000 V, respectively and at the anode-cathode spacing of 2000 μm. The emission image became brighter and the luminous image with dot matrix on the anode plate obviously increased with the increase of the gate voltage. Moreover, the emission current fluctuation was smaller than 5% for 11 h, which indicated that the improved planar-gate triode has a good field emission performance and long lifetime. 相似文献
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Field-emission displays (FEDs) have been studied intensively in recent years as a candidate for flat-display panels in the future. In a FED, electrons emit from field emitters. Some electrons may impinge on the insulator surface between cathode and gate electrodes and cause charging of that surface because the yield of secondary electron emission is usually not equal to one. The charging of the insulator walls between cathode and gate electrodes is one of the important factors influencing the performance of a FED. In this paper, a simulation program is used to calculate this charge deposition, electric field distribution and electron trajectories. From the change of the electric field upon charge deposition in the triode region, it is shown that the insulator surface is negatively charged at a low gate voltage, e.g. 20 V. However, positive charge is deposited when the gate voltage is high, e.g. 100 V. The simulations also show that the emission current will increase even further after coating the dielectric with a thin film of a material with a high-secondary emission coefficient such as MgO. If a cone-shaped dielectric aperture is used in a triode, the emission current will decrease after charge deposition. However, the focus performance of the electron beam is improving in this case. 相似文献
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A hexagon pitch carbon nanotube (CNT) array vertical to
the normal gate of cold cathode field emission displayer (FED) is
simulated by solving the Laplace equation. The calculated results
show that the normal gate causes the electric field around the CNT
tops to be concentrated and emission electron beam become a column.
The field enhancement factor and the emission current intensity step
up greatly compared with those of diode structure. Emission current
density increases rapidly with the decrease of normal-gate aperture.
The gate voltage exerts a critical influence on the emission
current. 相似文献
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Jianfeng Dai Xiaowen Mu Xiaoting Chen Junhong Wang Bi Fu 《Physica E: Low-dimensional Systems and Nanostructures》2011,44(1):152-155
The field emission performances of normal-gate cold cathode, which is composed of different multi-wall carbon nanotubes (MWCNTs) bundles array are calculated. The device parameters such as the arrangement of bundles, array density, gate location, gate voltage, anode voltages and anode–cathode distance affect the field emission properties, which is discussed in detail. The results reveal that the hexagon bundles array needs a lower threshold voltage than square array to reach high field enhancement factor and large emission current density. The emission current density is two orders larger than that of the oxide emitter. The optimal bundles array densities of hexagon and square array to get field enhancement factor are 0.0063 and 0.00375 μm−2, respectively. Meanwhile, the field emission performances are impacted critically by gate location and gate voltage. Field emission properties changed little while the anode–cathode distance varies within tens of micrometers, which increases the process-friendliness of CNTs field emission devices. 相似文献
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采用硅的局部氧化技术以及湿法刻蚀技术,利用2.6 μm的光刻掩模板在n型硅片上形成了栅极孔径为1 μm的场发射阴极的栅极空腔阵列,实现了用大阵点尺寸的栅极掩模板制备较小尺寸栅孔阵列。硅的湿法刻蚀溶液采用各向同性的硝酸和氢氟酸混合溶液,刻蚀后空腔的深度和宽度均随刻蚀时间线性增加。同时,由于刻蚀溶液具有较高的Si/SiO2 刻蚀选择比,栅极孔径随刻蚀时间增大的速度远低于深度和宽度增大的速度,栅极孔径主要取决于掩模的尺寸和氧化层的厚度。通过选择掩模板的尺寸以及氧化层的厚度,采用局部氧化技术和湿法刻蚀技术能够制备出微米或亚微米的场发射阴极的栅极空腔阵列。 相似文献
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X.Q. Wang M. Wang H.L. Ge Q. Chen Y.B. Xu 《Physica E: Low-dimensional Systems and Nanostructures》2005,30(1-2):101-106
To optimize the field emission of the infinite carbon nanotubes (CNTs) array on a planar cathode surface, the numerical simulation for the behavior of field emission with finite difference method was proposed. By solving the Laplace equation with computer, the influence of the intertube distance, the anode–cathode distance and the opened/capped CNT on the field emission of CNTs array were taken into account, and the results could accord well with the experiments. The simulated results proved that the field enhancement factor of individual CNT is largest, but the emission current density is little. Due to the enhanced screening of the electric field, the enhancement factor of CNTs array decreases with decreasing the intertube distance. From the simulation the field emission can be optimized when the intertube distance is close to the tube height. The anode–cathode distance hardly influences the field enhancement factor of CNTs array, but can low the threshold voltage by decreasing the anode–cathode distance. Finally, the distribution of potential of the capped CNTs array and the opened CNTs array was simulated, which the results showed that the distribution of potential can be influenced to some extent by the anode–cathode distance, especially at the apex of the capped CNTs array and the brim of the opened CNTs array. The opened CNTs array has larger field enhancement factor and can emit more current than the capped one. 相似文献
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Fabrication and properties of film-under-gate field emission arrays with SnO2 emitters for flat lamp
Y.A. Zhang 《Applied Surface Science》2010,257(1):306-3264
The film-under-gate field emission arrays (FEAs) have been fabricated on the glass substrates by conventional photolithography, anodic oxidation and lift-off method. SnO2 emitters were deposited on the cathode electrodes of under-gate triode by screen printing. The image of film-under-gate field emission arrays with SnO2 emitters was measured by the optical microscopy and field emission scanning electron microscopy (FESEM). The electric field distributions and electron trajectories of film-under-gate triode were simulated in the same anode voltage and different gate voltage by ANSYS. I-V characteristics of film-under-gate triode with SnO2 emitters were investigated. It indicated that the SnO2 emitters by screen printing uniformly distributed on the surface of cathode electrodes. The maximum anode current in this triode structure could come to 385 μA and the highest lightness was approximately 270 cd/m2 as the gate and anode voltage was 140 V and 2000 V, respectively, at the anode-cathode spacing of 1100 μm. Moreover, the emission current fluctuation was less than 5% for 8 h. It showed that the fabricated device has a good stability of field emission performance and long lifetime, which may lead to practical applications for field emission electron source based on flat lamp for back light units (BLUs) in liquid crystal display (LCD). 相似文献
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We propose a scheme for a topological insulator field effect transistor. The idea is based on the gate voltage control of the Dirac fermions in a ferromagnetic topological insulator channel with perpendicular magnetization connecting to two metallic topological insulator leads. Our theoretical analysis shows that the proposed device displays a switching effect with high on/off current ratio and a negative differential conductance with a good peak to valley ratio. 相似文献
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Small-signal negative conductance of a field emission monotron was calculated, which was considerably higher than that of
a thermionic monotron due to strong bunching of emitted electrons in a field emission. The amplification constant of 28dB/mm
is achieved at THz wave region by applying the monotron to a distributed amplifier and is sufficient to overcome power loss
in a transmission line. In addition, a wide band frequency tunable electromagnetic wave source may be developed at THz wave
region by providing a low loss microstrip line resonator with field emission array due to the gate voltage dependent phase
constant of the line. 相似文献