Magnetic field effect on electron emission from plasma

The influence of external magnetic field on the significant parameters of electrons from laser induced plasma (LIP) is investigated. A Q-switched Nd:YAG laser (1064 nm, 9-14 ns, 10 mJ, 1.1 MW) is focused on annealed, 4N pure (99.99%) Silver target (2 × 2 × 0.2 cm³) for production of plasma under vacuum ∼10⁻³ torr. Temperature, density and energy measurements for electrons were made by self fabricated Langmuir probe both in the absence and presence of external magnetic field (∼1.2 T) at different positions. The signals are recorded on 200 MHz UTT 2202 digital storage oscilloscope. The results thus obtained reveal decrease in electron temperature, energy and density in presence of external magnetic field. Confinement of plasma is also observed.     

Stable electron emission from multipoint liquid-metal cathode

Low-frequency fluctuations of emission current from multipoint liquid-metal emitter power supplied in various regimes were studied. Images of the emitter surface before and after work were obtained. A change of the supply voltage amplitude for the transition from field emission to explosive emission regime were estimated.     

Multiparticle processes during field electron emission from structured carbon

The statistics of field electron emission (FEE) from structured carbon materials has been studied. Multiparticle FEE from fullerene-containing carbon has been observed. Analysis of the experimental data revealed correlations with the results of previous investigations of FEE in high-temperature superconductors. Possible models of the mechanism of multielectron processes are discussed.     

Correlated electron tunneling during the field electron emission

Elementary events of correlated electron tunneling from very small regions of a hollow metal emitter were detected. The most significant microscopic and macroscopic parameters favoring the appearance of multiparticle tunneling effects are considered.     

Enhanced emission during submillisecond low-energy electron beam generation in a diode with grid-stabilized plasma cathode and open anode plasma boundary

We have experimentally studied the phenomenon of emission enhancement in a gas-filled diode with grid-stabilized plasma cathode and open (mobile) anode plasma boundary at an accelerating voltage of up to 20 kV. As the working gas pressure is increased to p ≥ 10⁻² Pa and the longitudinal magnetic field is increased to B _z ≥ 20 mT, the current in the accelerating gap exhibits significant growth, sometimes by a factor of two or more. Experimental data show that the most probable mechanism responsible for this effect is ion-induced secondary electron emission from the emitting electrode surface bombarded by ions from plasma generated by the electron beam in the drift space. These ions are accelerated in the space charge layer between the emitting electrode surface and the mobile boundary of the beam-generated (anode) plasma.     

Electric field effect on the electron emission from Te-DX in AlxGa1−xAs

The present work is aimed to investigate the electron emission from DX centers in tellurium-doped Al_xGa_1−x As with aluminium composition x = 0.40 using deep-level transient spectroscopy. Evidence that Te-DX exhibits an alloy splitting is shown from the temperature-dependent emission at a given reverse bias. The Poole–Frenkel effect was evoked to explain the electric field-enhanced emission. A discrepancy to this model is observed from experimental results. An attempt to explain this discrepancy as due mainly to the short-range character of the Te-DX-related potential.     

碳纳米管场发射阴极的制备及其场发射特性

采用电泳法将碳纳米管组装到电化学淀积的银台阵列上作为场发射阴极并研究了它的场发射特性.场发射特性测试结果表明:该阴极具有优异的场发射特性,开启电场为2.8V/μm,在应用电场为5.5V/μm时,发射电流密度达到1.7mA/cm2.具有优异的发射性能的原因可以归结到银台的边缘和银台类山状的表面增强了碳纳米管的场致电子发射.该阴极制备工艺简单、发射特性优异,且容易实现大面积制备,可以应用到大面积场发射显示器件中.     

电泳法制备纳米金刚石场发射阴极

用电泳法制备了纳米金刚石场发射阴极，研究了不同热处理环境对场发射性能的影响．在气氛炉中热处理的样品其阈值场强为8．0V/μm，场发射电流密度在17．7V/μm场强下可达到1361aA/cm^2；而在真空环境中热处理样品的场发射特性与之相比有明显提高，其阈值场强为3．83V/Hm，场发射电流密度在9．44V/μm场强下可达到2801aA/cm^2。用X射线衍射（XRD）和扫描电子显微镜（SEM）对样品表面的结构、成份及形貌进行分析，表明真空环境下的热处理，更有利于样品的电子发射．     

基于氧化锌纳米线表面传导场发射阴极的研究

利用热蒸发和丝网印刷技术在玻璃基底上成功制备了氧化锌纳米线表面传导场发射阴极阵列,并测试其场发射性能。扫描电镜表明,在氩气和氧气流量分别为60和1mL/min,反应温度550℃保温30min条件下制备的氧化锌纳米线均匀垂直生长在玻璃基底上,直径大约在80～200nm,长度〉7μm。场发射测试表明,在阳压2000V和阴阳间距为500μm时,ZnO纳米线表面传导场发射阴极的开启电压为70V;在栅压为96V时,电子发射效率为26.2%,高于传统报道的表面传导电子发射器件,在经过80min的老练后发射接近稳定,平均发射电流接近135μA,表明ZnO纳米线表面传导场发射阴极有着稳定高效的场发射性能。     

The effect of diamond film grain size on electron field emission performance

Journal of Materials Science: Materials in Electronics - Diamond films with different grain sizes in the range of?~?9 nm to?~?50 μm have been...     

Negative ion emission accompanying the field electron emission from amorphous hydrogenated carbon

It was found that the field electron emission from the surface of amorphous hydrogenated carbon is accompanied by the emission of negative ions of hydrogen and hydrocarbons. This ion emission is explained by the formation and degradation of the local surface emission centers.     

大面积印刷纳米金刚石薄膜的场致发射的研究

研制了特定比例的纳米金刚石浆料,采用了丝网印刷工艺在石墨衬底上大面积印制了纳米金刚石场发射薄膜,实验探索了石墨衬底纳米金刚石薄膜的烧结工艺和后处理过程,利用扫描电镜(SEM)观察了纳米金刚石膜的表面形貌,经后处理的薄膜中纳米金刚石露出薄膜表面,纳米金刚石的棱角是天然的发射体.采用本课题组研制的多功能场发射测试台在10-6Pa的真空条件下进行了场发射特性的测试,结果发现石墨上低成本大面积印刷的纳米金刚石薄膜具有均匀稳定的场发射特性,作为电子器件的理想冷阴极发射,可在宇宙飞船、原子反应堆等恶劣条件下工作的平面显示器中得到应用.     

Multiparticle tunneling during field electron emission from Bi2CaSr2Cu2O8

An analysis of data on the experimental statistics of the field electron emission (FEE) from an oxide superconductor of the Bi₂CaSr₂Cu₂O₈ system reveals the multielectron tunneling effect. The spectral curves and statistical data obtained under various experimental conditions are considered, and possible mechanisms of the multiparticle tunneling are discussed.     

Effect of gas pressure on electron field emission from carbon nanotube forests

This article quantifies the effect of the operating pressure of the H2 + C2H4 gas mixture on the current density and threshold voltage of the electron emission from dense forests of multiwalled carbon nanotubes synthesized using thermal catalytic Chemical Vapor Deposition under near atmospheric pressure process conditions. The results suggest that in the pressure range of interest 400-700 Torr the field emission properties can be substantially improved by operating the process at lower gas pressures when the nanostructure aspect ratios are higher. The obtained threshold voltage approximately 1.75 V/microm and the emission current densities approximately 10 mA/cm2 offer competitive advantages compared with the results reported by other authors.     

铁电阴极几何参数对二极管电子发射的影响

主要讨论了触发电场的脉宽和阴极几何参数对铁电二极管电子发射的影响,通过对不同脉宽激励下的电子发射试验发现触发脉冲的最佳工作宽度范围是150-250ns。对不同几何参数铁电阴极片在正脉冲激励下的电子发射研究指出:一般实验条件下(触发电压小于4kV/mm),触发梯度电场相同时,阴极越厚,条栅电极越细密,发射电流密度越大;极化反转发射中前沿发射方式和后沿发射方式可以共时存在。     

用于二次电子发射阴极的纳米金刚石膜

为获得导电性和二次电子发射性能均好的金刚石阴极材料,分别以CH4/Ar/H2、CH4/N2及CH4/N2/H2混合气体作为反应气源,用微波等离子化学气相沉积(MWPCVD)法制备出不同组成结构特点的纳米金刚石薄膜.XRD和Raman检测表明3种气源条件下得到的膜材均为金刚石多晶膜,但用CH4/N2反应源沉积的膜材中非金刚石相成分明显更多;AFM分析证实所有膜层的平均晶粒尺寸均在100nm以下,属纳米晶金刚石膜.用自行设计的二次电子发射系数测量装置对比检测所得膜层的二次电子发射特性,结果表明各金刚石膜均在初级入射电子能量达约1keV时,有最高的二次发射系数(δmax);并且以CH4/Ar/H2反应源制备的金刚石相纯度最高的膜材的δmax最大,达到17左右,是适用于二次电子发射阴极的潜在材料.     

Temperature effect on the field emission from zirconium islands on tungsten

The coefficients α _T of the change in the work function with temperature are determined experimentally for two-dimensional islands of zirconium on and in the vicinity of the {001} face of tungsten. The values of α _T are an order of magnitude higher than those typical for clean metals. The reason is a change in the adatom-adatom binding energy with increasing temperature. Pis’ma Zh. Tekh. Fiz. 25, 69–73 (May 26, 1999)     

Peculiarities of field electron emission from submicron protrusions on a rough InSb surface

Technical Physics Letters - Mechanisms of field-electron emission (FEE) from submicron protrusions on a rough InSb surface have been studied. It is established that the FEE current is...     

Thermal decomposition and electrical conductivity of oxide cathode emission materials

Thermal decomposition and electrical conductivity of oxide cathode emission materials used for cathode ray tubes (CRTs) have been studied under different heat treatment conditions for commercial sprayed cathode systems based on barium-strontium carbonate precursors. Conversion of the carbonate precursor commenced at temperatures above approximately 700 K in vacuum, evidenced by increases in conductivity, however, the rate of the conversion reaction increased dramatically as the temperature was increased. The corresponding chemical and microstructural changes have also been investigated by thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM), with multiple decomposition stages identified corresponding to the conversion of the carbonate precursor and separate activation steps associated with the reaction of barium oxide with the Mg and Al activating agents in the nickel cathode substrate. © 2000 Kluwer Academic Publishers     

Linear field emission cathode with ZnO grown in aqueous solutions

A new type of linear field emission cathode with ZnO nanostructure grown on nickel wires was prepared by hydrothermal approach. The obtained ZnO nanotapers were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated that the ZnO nanotapers with sharp tips were high quality single crystals, and grow along (002) direction. The field emission properties were investigated by ZnO nanotapers on nickel wire as the cathode in the centre of a cylindrical ITO anode. The field enhancement factor β was about 2.23 × 10⁴ cm⁻¹, which improved greatly for the cylindrical configuration and sharp geometry of the ZnO nanotapers tip.