太赫兹真空电子器件用场发射阴极技术分析

本文阐述了太赫兹真空电子器件对阴极电子源的需求条件,分析了在该器件中应用场发射阴极的可能性。介绍了当前两种主要场发射阴极,即金属薄膜场发射阴极和碳纳米管场发射阴极的国内外发展情况,指出了它们各自的优势以及实际应用中存在的障碍,并提出了相应的解决途径。试验和分析结果表明,场发射阴极具有很好的太赫兹真空电子器件应用前景。     

太赫兹真空电子器件用场发射阴极技术分析

本文阐述了太赫兹真空电子器件对阴极电子源的需求条件,分析了在该器件中应用场发射阴极的可能性。介绍 了当前两种主要场发射阴极,即金属薄膜场发射阴极和碳纳米管场发射阴极的国内外发展情况,指出了它们各自的优势 以及实际应用中存在的障碍,并提出了相应的解决途径。试验和分析结果表明,场发射阴极具有很好的太赫兹真空电子 器件应用前景。     

W[111]场发射尖端的制作与使用

本文报道w[111]场发射尖端的制作,使用条件以及尖端的闪烁和重建。从实验得到其正常工作范围是尖端曲率半径在0.9～1.2×10～(-5)cm;第一阳极电位V_1在2～2.5KV之间。闪烁电压约3～4伏,时间0.5～2秒;w[111]尖端重建条件为尖端表面电场强度必须大于3×10～7V/cm,加热电压为30伏,时间1×10～(-2)秒。了解这些情况对场发射电子枪的正确使用和维护无疑是重要的,具有实用意义。     

场发射冷阴极的技术现状及其应用研究进展

基于场发射冷阴极的真空电子器件被广泛应用于通讯、医疗、安全监测等领域,本文主要回顾了近年来场发射冷阴极及其真空电子器件的最新研究进展,介绍了现行冷阴极中使用的低维纳米材料和新型复合式结构,详细探讨了场发射冷阴极在微波管、电子显微技术、X射线管及真空纳米间隙晶体管中的应用现状。最后,着重阐述了真空电子微系统的科学概念,并对未来的应用前景进行了展望。     

双栅极场发射阵列的特性模拟与设计

具有聚焦能力的双栅极场发射阵列(DGFEA)是两类最有发展前途的真空微电子器件(高分辨率场发射显示器和真空微电子微波、毫米波器件)的关键技术。本文简要比较了两种结构的DGFEA的主要性能和优缺点,叙述了双层栅极结构DGFEA的设计与模拟方法.从模拟计算获得的发射特性和聚焦性能可以看到:这种结构的DGFEA能获得几乎平行的场发射电子束,其最大发射电流密度可达到约500A/cm2以上,是发展真空微电子微波、毫米波器件和其它强流电子注器件等较理想的电子源。     

蔡司场发射扫描电镜Sigma500真空系统故障与排除

场发射扫描电镜是科研工作中不可或缺的重要工具之一,管理者要及时排查、解除故障,以缩短维修周期、节约维修经费,保障仪器高效有序运行.本文对蔡司Sigma 500真空系统在使用过程中发生的故障进行了分析排查并对解决方法进行了归纳总结,给同款仪器用户以借鉴.     

场发射阴极特性

介绍了场发射阴极阵列的特性。系统地介绍发射体材料的选择以及发射体形状与发射特性关系，获取最大发射电流密度，提高发射性能所采取的措施。     

W[111]尖端场发射电子枪的工作特性

本文报道了单晶W[111]尖端的制作,以及由W[111]尖端阴极,第一、二阳极组成的三极场发射电子枪(FEG)的工作特性。实验结果表明,这种FEG在枪室真空为510-7Pa,加速电压在30kV的条件下,其虚源半径为1.6nm;亮度为3.8109A/cm2.sterad;场发射电流为1A时,束流稳定性为5%(10min内)。说明它是一种较理想的点状电子源,在实际应用中具有广泛发展前景。     

场发射显示器及其进展

从场发射器显示器的特点,结构,工作原理及关键制备工艺等几个方面系统地描述了这种新型的平板显示部,并介绍了ＦＥＤｓ的最新发展动态。     

Numerical study on performance of pyramidal and conical isotropic etched single emitters

A full three-dimensional model was implemented in order to investigate the electrical characteristics of conical and pyramidal isotropic etched emitters. The analysis was performed using the finite element method (FEM). The simulations of both emitters were modeled using a combination of tetrahedral and hexahedral elements that are capable of creating a mapped and regular mesh in the vacuum region and an irregular mesh near the surfaces of the emitter. The electric field strengths and electric potentials are computed and can be used to estimate the field enhancement factor as well as the current density using the Fowler-Nordheim (FN) theory. The FEM provides results at nodes located at discrete coordinates in space; therefore, the surface of the emitter can be generated through a function interpolating a set of scattered data points. The emission current is calculated through integration of the current density over the emitter tip surface. The influences of the device geometrical structure on its potential distribution, electric field and emission characteristics are discussed.     

Analytical electrostatic model of silicon conical field emitters. I

We present an analytical electrostatic model for a conical field emitter surrounded by a circular gate. The model is based on a radially symmetric orthonormal expansion of the potential throughout all space in the basis of Legendre functions of nonintegral degrees. The “bowling pin” model (BPM) makes it possible to calculate the total emission current and electron trajectories. The calculated values of the emitted current are in good agreement with the data. The value for the tip radius of curvature (ROC) obtained as the adjustable parameter in the model is in good agreement with that obtained from independent numerical modeling of the same devices     

The electrical characteristics of a conical horn-reflector antennaemploying a corrugated horn

The electrical properties of a conical horn-reflector antenna of 2-3° beamwidth have been investigated over the frequency range of 12-18 GHz. It is shown that the employment of a corrugated horn reduces the characteristic spillover side lobe of the conical horn-reflector antenna by 15 dB and yields excellent main beam circularity over the full Ku band. This results from the taper of the field amplitude toward the edges of the horn aperture in both the E-plane and the H-plane illumination. The performance of the antenna makes it suitable for use in closely packed interferometers for radio astronomy     

Analytical electrostatic model of silicon conical field emitters.II. Extension to devices with focusing electrode

For pt. I see ibid., vol.48, no.1, p.134-43 (Jan. 2001). We extended the “bowling pin model” (BPM) presented in pt. I, to the case of double-gated conical field emitters. The model was used for trajectory calculations for both the single-gated and double-gated devices. Analysis also produced the governing relationship for the optimal operating voltages on the gate and focus electrodes of a double-gated emitter     

碳纳米管蒸发特性及其对场发射性能的影响

为了探究场发射阴极电流的跌落机制,采用四极质谱仪分析的方法研究高温蒸发对阴极场发射性能的影响。实验结果表明：碳纳米管阴极在1173 K以上温度时开始蒸发出碳;在1373 K高温下连续蒸发100小时,碳纳米管阴极的开启场强增加21.7%,阈值场强增加31.7%,增强因子减小16.2%,功函数增加11.9%。扫描电镜（SEM）和能量色散X射线光谱仪（EDX）分析显示：增大的功函数和减小的场增强因子降低了阴极的场发射性能。阴极材料的蒸发是阴极电流跌落的重要原因。     

Structure and electrical characteristics of silicon field emissionmicroelectronic devices

Field emission current was measured from arrays of wet chemically etched silicon cold-cathode diodes. Two types of cathode tips were measured both as-etched and after sharpening by low-temperature oxidation. The field enhancement increase resulting from tip sharpening is less than expected from simulation. The currents measured follow a Fowler-Nordheim characteristic and are temperature insensitive from 130 to 360 K. Turn-on voltage is near 4 V, a value much less than measured from most other field emission sources. With a 920-nm anode-cathode spacing, a minimum 0.2-μA current per cathode was found. Telegraph noise of about 1% at 20 V was observed. These sharpened silicon tips are a viable cold cathode for vacuum microelectronics and other electron device applications     

Atomically sharp silicon and metal field emitters

A method is described for forming atomically sharp silicon tips of less than 10-15° half-angle by utilizing a known oxidation inhibition at regions of high curvature; equally sharp silicon wedges are now made in a similar fashion. The sharp silicon tips serve as the starting point for forming sharp tips of W, β-W and gold. Field emission data from silicon emitters are compared with Fowler-Nordheim modelling and emission as a function of emitter-anode distance is described     

Low-voltage planar field emitters based on carbon nanotubes

Planar field emitters based on carbon nanotubes are studied in an ultrahigh-vacuum chamber and sealed-off vacuum devices. In the sealed-off devices, an emission current of 1 mA is obtained at a mean electric field of 5.2–5.8 V/μm and the relative fluctuation of the emission current is 0.2–0.4%. The emission characteristics of the devices remain unchanged over a storage period of one year.     

弓网系统降弓电弧电气特性仿真研究

基于Mayr电弧电路模型和Cassie电弧电路模型,考虑纵向气流吹弧效应,对电弧电压梯度U和电弧耗散功率P0进行修正,建立降弓电弧电路分析模型。研究降弓速度、降弓时刻以及降弓电弧电流对降弓电弧电压的影响。发现降弓电弧电压呈现近似线性的增长关系,降弓速度越高,降弓电弧电压增长得越快。降弓时刻对于电弧电压的影响主要体现在电弧电压出现的时刻差异,降弓电弧电压的波形基本一致。不同电弧电流情况下,电弧电压基本一致。文中的研究对于指导降弓操作、减轻弓网材料损失具有重要意义。