真空微二级管发射特性的解析解

通过保角变换方法，对具有椭圆锥形发射体的真空微电子二极管进行了研究，求得了二极管区域内电位分布和电场分布的解析表达式，进而得到了电场强度和场致发射电流密度与尖端曲率之间的关系。     

具有相分离InGaN有源层的白光发光二极管

韩国Kwangju理工学院光电子材料中心和材料科学工程系利用相分离InGaN有源层，无需添加荧光材料，制造出了白光发光二极管。这种二极管的白光发射归因于分离相InGaN三元合金中铟组分和类量子点富铟区域尺寸的宽分布。     

环形火山口式硅边缘阴极发射体特性研究

本文首次提出了新型环形火山口式边缘阴极发射体结构．采用国内现有的半导体工艺制备了这种结构的阴极发射体和二极管阵列．在高超净室的大气和10－4Pa真空下测量了这种二极管阵列的I－V特性．大气下发射的开启电压大约为150伏，真空下的发射开启电压大约为70伏．最后还讨论了制备工艺中光刻套准偏差对发射的影响．分析结果表明偏心对发射的影响并不很明显．     

真空微电子二极管及微位移传感器的研究

首次用电荷模拟法计算了真空微电子二极管及真空微电子微位移传感器的场致发射阴极与阳极间的电场分布,进而计算了真空微电子二极管的电流一电压特性和微位移传感器的电流——位移(即阴、阳极间距)的关系曲线。模拟了两种结构的场致发射阴极:圆锥形和劈形。并用测试精度可达4nm 的水槽法模拟实验对计算结果进行了验证,理论计算与实验结果符合地很好。     

垂直腔环形激光器

垂直腔环形激光器１．引言大家知道，我们需要一种高功率相干二极管激光源。为实现这一要求，已经使用了许多方法．包括瞬逝耦合边缘发射激光器一维阵列［１］，光栅耦合分布是布拉格反射器表面发射激光器二维阵列［２］，垂直腔法布里－珀罗激光器二维阵列［３，４］。本...     

有助于防止激光二极管毁坏的激光仿真器

激光二极管可能在数纳秒内自行毁坏，因此测试一个反馈稳定的激光二极管驱动器的响应和稳定性可能是费用很高的。图1所示仿真器电路示出了一个典型的激光二极管封装，封装内不仅有由电流1．驱动的激光二极管，而且还有一个光电二极管。激光二极管的前端面发射在外界起作用的主光束，而后端面则发射落到光电二极管上的参考光束。     

硅尖阵列二极管温度性能的研究

简述了真空微二极管的结构参数设计、工作特点、工艺制备技术。给出了微二极管不同的温度下Ｆ－Ｎ曲线及湿法化学腐蚀制备硅尖的形貌。该微二极管起始电压为２Ｖ左右，发射尖电流５μＡ／锥尖。     

钼阳极二极管测试大尺寸阴极发射性能的应用研究

针对大尺寸、高功率阴极在工程应用上的发射性能检测不准确问题,我们设计了不同钼阳极二极管结构并进行仿真计算,选择不同直径和深径比的阴极进行实验。仿真计算结果显示球面、栅网阳极二极管的结构可较好地表征了阴极发射电流,明显优于平面阳极二极管结构。应用研究结果与仿真结果一致,考虑工程应用成本,球面阳极二极管结构利于筛选出工程应用阴极。     

硅尖阵列二极管性能的研究

简述了真空微二极管的结构参数设计考虑、工作特点、工艺制备技术。给出了微二极管不同温度下的Ｆ－Ｎ曲线及湿法腐蚀制备硅尖的开貌。该微二极管转换电压为２伏左右，发射锥尖电流为５μＡ／锥尖。     

AlGaN/GaN肖特基二极管漏电流传输机制与模型

制备了一种势垒层为非掺杂Al0.27Ga0.73N的AlGaN/GaN肖特基二极管。通过拟合不同温度和应力时间下的电流数据,研究了该肖特基二极管的反向漏电流的传输机制和模型。研究表明,在不同温度下,ln(I/E)与E1/2呈线性关系,电流由Frenkel-Poole(FP)发射主导。考虑极化电场和势垒层缺陷的影响,对FP发射模型进行了修正。对修正后的FP模型进行了光发射显微镜测试。测试结果表明,AlGaN/GaN肖特基二极管漏电流的传输机制为高电场通过缺陷发射电子,缺陷的势垒高度约为0.3 eV。     

Theoretical Study on Field Emission Patterns of the Nanotube

The distributions of the electrical potential and field have been given from Maxwell‘s field equations. The results show that there exists very strong electric field intensity on the tip of the nanotube,and the intensity decays rapidly as the distance increases away from the tip. The strong electric field intensity on the tip is consistent with the low threshold voltage under the electric field emission from a nanotube. The calculation also revealed that the higher the aspect ratio is, the stronger the electric field intensity on the tip of the nanotube will be,if the distance and voltage between the cathode and the anode do not change, which predicts the lower threshold voltage under the field emission.     

场致发射尖端电场分布及其模拟误差研究

场致发射器件中,发射电流密度的大小和阴极表面场强呈指数关系,较为精确地计算尖端附近场强对精确计算发射电流是至关重要的。本文主要研究了不同网格划分对模拟结果产生的影响,对比了解析解和模拟结果,分析了网格细化过程中产生的误差;讨论了尖端半径、发射体高度、锥尖距离对球形顶圆锥模型尖端场强的影响。研究表明,随着网格尺寸的减小．模拟精度可以得到提高;但是当网格尺寸减小到某一数值后,误差值反而增大。最小网格尺寸约为尖端半径的1．5％时模拟结果最佳。     

同轴双栅极SPINDT阴极的模拟与分析

描述了双栅极场致发射阴极的电子束聚焦问题.通过IESLORENTZ-2D 对单栅极单个SPINDT微尖的模拟,表明模拟与实验数据符合得很好.对带有同轴聚焦电极的单个SPINDT微尖也进行了模拟,并且分析了影响电子束聚焦的各种几何和电参数.结果表明,为了满足设计标准,应当同时考虑聚焦效果和发射特性.     

A theoretical study on field emission array for microsensors

The authors present results on the analysis of two generic cone-shaped and wedge-shaped emitter-array diodes. The effects of the variations in device geometrical structure on the potential distribution, electric field, and emission current are discussed. The main geometric design parameters considered are the tip-to-collector distance, the emitter tip radius of curvature, and the intertip spacing. Pressure sensors based on these diode structures with one electrode fabricated on a pressure sensitive thin diaphragm were studied. The analysis shows that a cone-shaped emitter array has a larger emission current per emitter tip, but the wedge-shaped array has better pressure sensitivity     

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.     

Ultralow-voltage boron-doped diamond field emitter vacuum diode

A boron-doped diamond field emitter diode with ultralow turn-on voltage and high emission current is reported. The diamond field emitter diode structure with a built-in cap was fabricated using molds and electrostatic bonding techniques. The emission current versus anode voltage of the capped diamond emitter diode with boron doping, sp² content, and vacuum thermal electric (VTE) treatment shows a very low turn-on voltage of 2 V. A high emission current of 1 μA at an anode voltage of less than 10 V can be obtained from a single diamond tip. The turn-on voltage is significantly lower than comparable silicon field emitters     

On relationship between the field at an autoemitter top, anode voltage and cathode geometry

Currently a lot of electron emission experiments both in carbon nanotubes with top curvature radius <1 nm, and in emitters as short as 10³ nm with top curvature radius of some tens nanometer are carried out. Experimental results can be explained by a tunnel emission through potential barrier in vacuum near the solid-state cathode border making use of Fowler-Nordheim law. However, in case of cathodes with radius of top curvature less than 100 nm this law is not valid.To proof this statement, the potential of an autoemission diode consisting of a tip cathode located on a flat metal base and flat anode, its dependence on the shape, height of the tip as well as voltage drop on it were calculated in this paper. It has been shown that with cathode tip height and its radius of curvature decreasing (?100 nm) the transparency of the potential barrier depends non-linearly on the anode voltage in the Fowler-Nordheim coordinates when the cathode tip height decreases from 1000 down to 150 nm. To obtain a measurable autoemission current, work function must not exceed the uniform field’s potential drop between cathode top and its base. Deduced is the analytic formula for the electric field potential that extends approximation features for real cathodes shapes and enables more accurate electric field modeling at the surface.     

A physical simulation model for field emission triode

A simple but accurate physical model, which can be incorporated into circuit simulation programs such as SPICE for the field emission triode (FET), is developed. The model is based on the Fowler-Nordheim (F-N) current density-electric field (J-E) relationship. An electric field form is adopted to calculate the current density distribution along the surface of the sphere-shape tip. The cathode current is obtained by integration of the current density over the emission surface. The gate current is derived by the same integration, but over part of the emission area. A procedure to extract the values for the parameters of the model is also given. The model and the procedure has been applied to experimental devices to demonstrate its accuracy     

基于计算机仿真的ZnO场致发射显示器的研究

在Spindt结构仿真方法的基础上,将四针状纳米ZnO近似处理成尖锥结构,采用C语言程序编程,求解电位、电场分布、电子运动轨迹及发射电流密度。通过计算机模拟仿真,分析了栅极孔径、栅极电压以及阳极电压等对显示器性能的影响。在理论优化设计指导下,采用丝网印刷制作带孔的介质层,用电泳方法在阴极电极上沉积ZnO发射体,制成孔状金属栅三极结构显示屏。测试了显示器的电子发射调制性能,实验表明采用计算机仿真设计的三极结构ZnO场致发射显示器具有良好的场致发射性能。     

锥形与金字塔形场发射尖端电学特性分析

场致电子发射具有高效、响应快等优点,有着广泛的应用前景。锥形和金字塔形尖端是两种常见的场发射尖端结构。主要分析了这两种尖端结构的场发射电学特性,并在此基础上提出了进一步实现结构优化的途径。为此,建立了两种尖端的三维模型,并利用有限元法深入讨论了结构尺寸,包括尖端曲率半径、尖端与阳极间距以及尖端高度对电场分布以及电场强度的影响。结果表明,减小尖端曲率半径、缩短尖端与阳极间距、以及选择适当的锥体高度是优化尖端场致电子发射性能的三个重要途径。在综合考虑电场分布以及电场强度的情况下,可以发现锥形尖端更有利于产生高密度小束径的低能电子束,而金字塔形尖端则更适用于高压力灵敏度的应用需求。