硅基场发射阴极材料研究进展

场发射显示技术在原理上具有多种优越性能,可能在未来平板显示技术中居主导地位。硅基场发射阴极易于与其周边驱动电路实现集成,因而更具有明显的开发前景。在综述硅基场发射阴极材料最新研究进展的基础上,就其所面临的问题、可能的解决方案和未来的发展趋势做出了评述。     

O2吸附对纳米石墨片的场发射性能影响

采用（CVD）法制备了纳米石墨片,用场发射扫描电镜（FESEM）和Raman光谱对其形貌和结构进行表征,发现其为花瓣片状结构,边缘具有突出尖端。利用二极结构分别测试了有无O2氛围下纳米石墨片场发射电流,发现O2吸附在纳米石墨片表面时,场发射电流明显减小,开启电场增大。在冷阴极方面有较好应用前景。     

FESEM荷电消除技术中各参数的选择机制研究

场发射扫描电子显微镜(FESEM)在研究材料表面形貌领域有广泛的应用.荷电现象是扫描电镜中影响图像质量的重要原因之一.为了消除荷电现象,获得不导电样品真实清晰的扫描电镜图片,从荷电效应的产生机理出发,利用配备X线能谱仪的场发射扫描电镜,通过调节加速电压、驻留时间、探测器类型、扫描方式、及光阑孔径等参数,对比分析土壤、聚...     

Multiferroic and magnetoelectric properties of La0.1Ba0.9Fe12O19 ceramics

La0.1Ba0.9Fe12O19 powders with similar hexagonal crystal structure to Ba Fe12O19 have been successfully synthesized using polymer precursor method. The powders were suppressed into pellets, which were sintered into ceramics at 1,300 °C for 1 h. The structure and morphology of the ceramics have been determined by X-ray diffraction（XRD） and field emission scanning electron microscopy（FESEM）. Clear electric hysteresis loops upon different amplitude of external fields indicates that La0.1Ba0.9Fe12O19 is a kind of possible ferroelectric compound. The maximum remnant polarization of La0.1Ba0.9Fe12O19 ceramic is estimated to be ＊9.6 l C/cm2. The Fe O6 octahedron in its perovskite-like hexagonal unit cell as well as the shift of Fe3？off the center of octahedron are proposed to be the origin of electric polarization in La0.1Ba0.9Fe12O19. Simultaneous occurrence of large ferroelectricity and strong ferromagnetism has been observed in La0.1Ba0.9Fe12O19 ceramics. More interestingly, this compound demonstrates electronic polarization behavior being actuated by an applied magnetic field, indicating the existence of magnetoelectric（ME） coupling effect in the La0.1Ba0.9Fe12O19 ceramics. Our results may lead to new device applications such as magnetically recorded ferroelectric memory.     

Enhanced Field Emission from Printed Carbon Nanotubes by Hard Hairbrush

A method, the morphology of screen printed carbon nanotube pastes is modified using a hard hairbrush, is presented. In this way, the organic matrix material is preferentially removed. Compared to those untreated films, the turn-on electric field of the treated film decreases from 2.2V/μm to 1.6V/μm, while the total emission current of the treated increases from 0.6mA/cm2 to 3mA/cm2, and uniform emission site density image has also been observed.     

惰性盐辅助法合成氮化镓纳米棒及其场发射性能研究(英文)

以惰性盐为分散剂,通过直接氮化金属镓与氟化钙的混合物,在较低温度下(650℃)大量合成出角面截面型氮化镓纳米棒,大大低于以往文献报道的氮化温度(900℃以上)。通过X射线衍射和电子显微镜等设备表征,可知所制得的产物为六方相氮化镓纳米棒,且纳米线沿着c轴择优生长;每根氮化镓纳米棒都具有菱形或三角形截面。由于本方法的制备温度低,导致了氮化镓纳米棒与硅基片的良好接触。场发射实验表明,该复合系统具有很低的开启电压(5.4V/μm)和阈场(8.4V/μm)。     

氮离子轰击改善胶体石墨薄膜平面场发射特性的研究

研究了氮离子(N )轰击对石墨薄膜场发射特性的影响。片层石墨被N 轰击成较整齐排列的锥尖阵列,尖端密度~108cm-2。XPS谱证实有许多N原子注入薄膜,膜内存在大量sp2杂化轨道键。场发射测试表明,经过N 轰击,整个薄膜在场发射的均匀一致性方面有较明显的改善,场发射电流密度从0·3增大到1·65mA/cm2。     

Si-TaSi2共晶自生复合场发射材料的组织与性能

采用电子束悬浮区熔(EBFZM)技术制备了Si-TaSi₂共晶自生复合场发射材料, 并系统地对比了Czochralski(CZ)和EBFZM两种不同晶体生长技术所得到的Si-TaSi₂共晶自生复合材料的定向凝固组织特征和场发射性能. 研究表明, EBFZM法由于较高的凝固速率和较高的温度梯度, 使凝固组织明显得到细化, 也就是与CZ法制备的TaSi₂纤维相比, EBFZM技术制备的TaSi₂纤维的直径和纤维平均间距减小, 面密度和体积分数增大. 因此改善了Si-TaSi₂共晶自生复合材料的场发射性能, 表现为较好的场发射均匀性和更平直的F-N曲线.     

基底偏压对氮化硼薄膜场发射特性的影响

利用射频磁控溅射方法, 在n型（100）Si（0.008～0.02 Ω·m）基底上沉积了氮化 硼（BN）薄膜. 红外光谱分析表明, BN薄膜结构均为六角BN（h-BN）相. 在超高真空系统中 测量了BN薄膜的场发射特性, 发现BN薄膜的场发射特性与基底偏压关系很大, 阈值电场随基 底偏压的增加先增加后减小. 基底偏压为-140 V时BN薄膜样品场发射特性要好于其他样品, 阈值电场低于8 V/μm. F~N曲线表明, 在外加电场的作用下, 电子隧穿BN薄膜表面势垒发射 到真空.