碳纳米管场致发射特性的研究进展

碳纳米管(CNT)具有优良的场致发射特性,是场致发射器件的理想阴极材料。本文介绍了几种碳纳米管阵列的制作方法以及研究碳纳米管场致发射特性的理论和实验进展。     

碳纳米管场发射微焦点高速X射线管

具有快速启动和高速拍照特性的微焦点X射线管具有广泛的应用需求。一种基于碳纳米管场致发射阴极阵列的微焦点X射线管研制成功。采用由微波等离子体化学气相沉积方法制备出的高度定向的、具有优异场致发射性能的碳纳米管微束阵列作为X射线管的冷阴极,以此设计出由六边型铜网为栅极的多级式高分辨率电子光学系统,使该X射线管可以实现高速脉冲拍照特性。当栅极电压为2.7kV时,总发射电流达到2mA,碳纳米管相应的发射电流密度达到2.5A/cm2,此时X射线的焦斑尺寸为39μm,从而可以实现高分辨率X射线成像。     

碳纳米管的场发射特性

研究了碳纳米管的场致发射特性,实验证明碳纳米管作为场发射阴极材料具有优越性.通过对碳纳米管进行温度处理,得到了与基片附着力强的碳纳米管;测试了场发射特性,发现碳纳米管其开启电压较低(30V).     

碳纳米管的场发射特性

研究了碳纳米管的场致发射特性,实验证明碳纳米管作为场发射阴极材料具有优越性.通过对碳纳米管进行温度处理,得到了与基片附着力强的碳纳米管;测试了场发射特性,发现碳纳米管其开启电压较低(30V).     

化学镀铜Si基底上碳纳米管薄膜强流脉冲发射稳定性研究

为了研究碳纳米管薄膜在强流连续多脉冲下的发射特性,采用酞菁铁高温热解方法在化学镀铜硅基底上生长了碳纳米管薄膜(Si/Cu-CNTs),作为强流脉冲发射阵列。在20GW脉冲功率源系统中采用二极结构对Si/Cu-CNTs薄膜进行连续多脉冲高电流发射测试,结果表明:连续多脉冲情况下,峰值电场达到29.1V/μm,发射电流密度为0.892kA/cm2时,Si/Cu-CNTs薄膜仍具有良好的发射可重复性,连续发射的每个电流波形基本一致,发射稳定性好。     

电泳法制备平栅极碳纳米管场发射阴极及场发射特性研究

采用电泳法在ITO玻璃基板上选择性制备了碳纳米管(CNTs)阴极薄膜,采用电子扫描(SEM)分析了CNTs薄膜的表面形貌,并测试了碳纳米管阴极的场致发射特性.结果表明,利用电泳法制得的碳纳米管阴极薄膜均匀性、致密性良好,且具有较大发射电流密度;通过控制共面栅控CNTs场发射阴极的栅极电位能够有效控制阴极的场发射电流密度...     

碳纳米管场致发射平面背光源

通过酸化、球磨、超声分散等工艺制备碳纳米管(Carbon Nanotubes,CNT)悬浮液,利用电泳沉积技术制备CNT阴极,并真空封装制备成25.4cm(10in)的CNT场致发射平面背光源器件。采用扫描电子显微镜对CNT阴极样品的表面形貌进行表征,并对器件的场致发射性能进行测试。结果表明,当电场为1.76V/μm时,CNT场致发射平面背光源器件的亮度为6500cd/m2,亮度均匀性为89%,可应用于液晶显示器的背光源。     

碳纳米管的场发射特性

研究了碳纳米管的场致发射特性，实验证明碳纳米管作为场发射阴极材料具有优越性。通过对碳纳米管进行温度处理，得到了与基片附着力强的碳纳米管；测试了场发射特性，发现碳纳米管其开启电压较低(30V)。     

表面形貌对定向氧化锌阵列场致发射性能的影响

采用热蒸发的方法生长不同形貌的ZnO纳米材料。通过调节反应温度和氧气流量,生长了梳状ZnO ,ZnO纳米针和ZnO纳米柱状。场致发射测试结果表明一维纳米ZnO材料的表明形貌对其开启电场和发射电流有很大的影响。ZnO纳米柱阵列的开启电场最低,电流密度最大。这是由于它与衬底的良好接触以及较弱的场屏蔽效应。实验结果表明ZnO纳米柱阵列是一种优良的场致发射器件的冷阴极材料。     

单根碳纳米管阴极场致发射特性研究

碳纳米管具有优异的场致发射性能,是一种很有前景的电子发射源。本文初步探讨了纳米材料发射理论机制,利用电磁计算软件CST建立仿真分析模型,并针对其具体结构特点构造了合适的仿真环境,通过仿真计算取得的成果对于研制采用碳纳米管阵列作为场致发射阴极的微波管有重要的理论指导作用。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.