碳纳米管复合阴极的稳定性研究

基于隧穿效应的双势垒模型,采用Sol-Gel法在ITO玻璃基底上制备了SiO2涂层碳纳米管阴极,利用SEM对阴极的形貌、结构进行分析,并对场发射性能、发射稳定性与发光特性进行研究,获得了发射电流高,稳定性良好的阴极.测试结果表明: SiO2质量分数为20%时阴极具有比较高的发射电流及较好的场发射稳定性能;阴极开启场为1.71 V/mm,在场强为2 V/mm时,发射电流密度为65 μA/cm2;发射电流在3 h内,波动小于3%.低成本丝网印刷制备的该阴极,适合于不同尺寸器件的冷阴极.     

四针状氧化锌/碳纳米管复合阴极的制备及其场发射性能研究

采用丝网印刷技术制备四针状氧化锌(tetrapod-liked zinc oxide nanoneedles, T-ZnO)场发射阴极, 通过向T-ZnO阴极表面电泳沉积碳纳米管(carbon nanotube, CNT)薄膜制备了T-ZnO/CNT复合阴极。扫描电子显微镜观察表明: 与T-ZnO阴极相比, T-ZnO/CNT复合阴极与衬底电极之间具有较大的有效接触面积。采用二极场发射器件结构研究T-ZnO和T-ZnO/CNT的场发射特性, 实验表明: 相对于T-ZnO阴极, T-ZnO/CNT复合阴极发射电流密度大、开启场强与阈值场强低、发射点密度高, 且具有良好的工作稳定性。     

尖锥阴极场致发射的稳定性研究

场致发射阵列（ＦＥＡ）平板显示器的实现，标志着ＦＥＡ发展到新的阶段，对ＦＥＡ的研究析的要求。场致发射的实验研究是目前推进ＦＥＡ技术的一种重要手段。文中主要从ＦＥＡ场致发射的过程和分析发射失稳现象，并从理论上加以探讨研究。结果表明，ＦＥＡ中发射不均匀是普遍的，设计中采取均流均温措施是必要的；ＦＥＡ使用前的老化钝化是必不可少的工艺手段；场致发射常伴随着热发射，对热发射的控制和利用是场致发射研究的重要内     

碳纳米管阴极平板显示器的工艺研究

碳纳米管场致发射显示器是一种新型的真空器件，也是一种具有巨大应用潜力的平板型显示设备。本文详细地介绍了碳纳米管场致发射原理，给出了碳纳米管阴极平板显示器的基本结构和工作原理，对于显示器件的真空封装，碳纳米管阴极装配，控制栅极制作等工艺问题进行了阐述和研究。采用这些技术，已经研制出了碳纳米管阴极场致发射显示器的样品。     

基于半导体工艺制备碳纳米管阴极图形阵列

提出一种成本低、简单易行的碳纳米管图形阵列制备技术。首先在硅基底上采用热解工艺生长碳纳米管(CNT)阴极,再用光刻腐蚀法制备阴极图形阵列。研究了掩模精度及腐蚀液的浓度对图形阵列的影响,对所得到的图形样品进行XPS分析表明,图形腐蚀彻底、图形边沿轮廓清晰;以二极管结构FED测试场发射性能知:该阴极开启场1.5V/μm;在电场强度为2.0V/μm下,电流密度为58mA/mm2,发光亮度高达450cd/m2。     

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。     

真空微电子学中的场致发射阴极制备

近年来,随着微机械加工技术的不断发展,人们对小功率的场致发射阴极的研究日趋活跃,本文介绍了近年来国内外对场致发射阴极的制备,电学特性及应用方面的研究进展情况,并说明该技术的发展必将取得更广泛的应用.     

钼尖场致发射阵列阴极的性能研究

利用微细加工技术和双向薄膜沉积技术对钼尖场发射阵列阴极的工艺进行了较为细致的研究，并在专用的真空系统中对所得阵列阴极的发射性能进行了测试，得到了一定的场致发射电流密度值。测试中采用数据采集系统监测栅极电压、阳极电压、阳极电流和栅极电流，测量了阴极阵列的发射稳定性和发射噪声。对发射的失效机理进行了实验研究和分析，认为发射失效的主要原因在于栅极和基底之间的漏电，尖锥和棚极孔间的暗电流，电极间的放电和放气，以及环境真空度和尖锥的均匀性等。所得结果以进一步开展有射频器件和显示器件方面的应用研究打下了一定基础。     

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)。     

A Composite Fabrication Sensor Based on Electrochemical Doping of Carbon Nanotube Yarns

This work shows evidence of conventional liquid and polymer molecules doping macroscopic yarns made up of carbon nanotubes (CNT), an effect that is exploited to monitor polymer flow and thermoset curing during fabrication of a structural composite by vacuum infusion. The sensing mechanism is based on adsorption of liquid/polymer molecules after infiltration into the porous fibers. These molecules act as dopants that produce large changes in longitudinal fiber resistance, closely related to the low density of carriers near the Fermi level of bulk samples of CNT fibers, reminiscent of their low‐dimensional constituents. A 25% decrease in fiber resistance upon exposure to electron–donor radicals formed during epoxy vinyl ester polymerization is shown as an example. At later stages of curing the matrix undergoes shrinkage and applies a compressive stress to the fibers. The resulting sharp increase in electrical resistance provides a mechanism for detection of the matrix gel point. The kinetics of resistance change during polymer ingress are related to established models for macromolecular adsorption, thus also enabling prediction of polymer flow. This is demonstrated for vacuum infusion of a 150 cm² glass fiber laminate composite, with the CNT fiber yarns giving accurate prediction of macroscopic resin flow according to Darcy's law.     

Role of Gate in Triode-Structure for Carbon Nanotube Cold Cathode

Field emission properties of carbon nanotube cold cathode(CNT-CC) of triode- and diode-structure have been investigated by using the finite element method of numerical simulation. Specially,the effects of gate voltage and hole radius R on the emission properties have been analyzed based on the finite element method. Results indicate that the gate can make the excitation electric field E increase, turn-on voltage decrease, and the emission current density J rise. The result shows that the E reaches its maximum value at the top of carbon nanotube(CNT), and the optimum field emission performance can be obtained when R is equal to 10 times the diameter of the carbon nanotube.     

新型三极碳纳米管场发射器件的研究

采用催化剂高温分解方法制备了碳纳米管薄膜阴极。利用优质云母板作为绝缘材料．结合简单的丝网印刷工艺制作了新型的栅极结构。详细地给出了新型三极碳纳米管场发射器件的制作工艺．对场致发射的机理进行了初步的讨论。采用这种新型的栅极结构．不仅极大地降低了总体器件成本．同时避免了碳纳米管薄膜阴极的损伤．提高了器件的制作成功率。所制作的三极结构平板场发射器件具有良好的场致发射特性和栅极控制能力。     

Stability of Doped Transparent Carbon Nanotube Electrodes

This paper evaluates the effectiveness of p‐doping transparent single‐walled carbon nanotube (SWNT) films via chemical treatment with HNO₃ and SOCl₂. Stability of the improvement in electrical conductivity after doping is investigated for different doping treatments as a function of exposure time to air and as a function of temperature. Doped films were found to have a greater than twofold increase in conductivity with sheet resistance values as low as 105 Ω sq^?1 with an optical transmittance of 80% at 550 nm. However, doping enhancements demonstrated limited stability in air and under thermal loading. The application of a thin capping layer of PEDOT/PSS is shown to stabilize the improvements in conductivity, evidenced by sustained lower sheet resistance in both air and under thermal loading.     

可驱动碳纳米管冷阴极数码管的研制

采用印刷技术实现了碳纳米管阴极的大面积、低成本制备，并采用等离子体表面改性技术来提高阴极的发射性能。在此工艺基础上，自行设计和封装了七段显示的碳纳米管冷阴极数码管，配以简单的驱动电路，实现了碳纳米管冷阴极数码管的动态显示。     

高性价比小型C波段宽带跳频源的研制

选取具有数字接口、高集成度的锁相环(PLL)电路,实现了具备低相位噪声、快跳变、低杂散、高稳定度C波段宽带跳频源的发射机设计方案,系统跳频速度高于10 000跳/s,跳频带宽达240 MHz,数据传输速率快,体积约50 mm×70 mm×30 mm.按照该设计方案制作完成了具体的电路,经过实际测试,验证了该电路便于数字控制,体积小,成本低,系统的整体性能优异.     

碳纳米管非对称接触结构制作及电学性能研究

实验研究了多根或单根单壁碳纳米管与非对称金属电极接触结构的制作方法。先用介电泳方法(DEP)将碳纳米管定向排列在Au电极对之间,再用电子束光刻(EBL)在碳纳米管的一端加工Al电极,获得多根碳纳米管与金铝电极的非对称接触结构。先用EBL在Au电极对一端覆盖Al电极,再用DEP排列碳纳米管,实现单根碳管与金铝电极的非对称接触结构。非对称结构器件的电学测试研究表明,器件的I-V曲线不再对称,呈现出整流特性。     

Fabrication and Electrical and Mechanical Properties of Carbon Nanotube Interconnections

Individual carbon nanotubes (CNTs) have been cut, manipulated, and soldered via electron‐beam‐induced deposition of amorphous carbon (a‐C) and using a scanning tunneling microscope inside a transmission electron microscope. All CNT structures, including simple tube–tube connections, crossed junctions, T‐junctions, zigzag structures, and even nanotube networks, have been successfully constructed with a high degree of control, and their electrical and mechanical properties have been measured in situ inside the transmission electron microscope. It is found that multiple CNTs may be readily soldered together with moderate junction resistance and excellent mechanical resilience and strength, and the junction resistance may be further reduced by current‐induced graphitization of the deposited a‐C on the junction.     

最佳碳纳米管场发射阴极阵列密度的研究①

碳纳米管(CNT)作为理想的场发射阴极材料。它在场发射阴极阵列中的密度与阴极的场发射性能有着非常密切的关系。本文通过模拟计算找出了最佳碳纳米管场发射阴极阵列密度，并通过实验进行了验证。实验证实浓度为2．5％的碳纳米管浆料制得的阴极有最佳的阵列密度。