ZnO-Ni壳核丝状阴极场发射特性研究

采用水热法在Ni丝上制备锥状ZnO,形成ZnO-Ni壳核丝状阴极。采用X射线衍射分析仪进行物相分析,表明该ZnO具有沿002面生长的取向。用扫描电子显微镜(SEM)观察其表面形貌,表明Ni的表面生长有一层分布均匀的锥状ZnO。通过场发射性能测试,结果表明ZnO-Ni壳核丝状阴极具有比平面结构中的ZnO纳米锥阴极更优良的场发射性能,并对该结果进行讨论。     

图形化氧化锌阵列的制备及其场发射性能研究

为了减小场发射的屏蔽效应,采用图形化技术对氧化锌(ZnO)纳米枝阵列进行调控,并研究图形化ZnO枝阵列的性能。首先采用光刻法在ITO导电玻璃上制备图形化ZnO种子层,再用电沉积法在图形化种子层上生长ZnO纳米枝阵列。利用扫描电子显微镜(SEM)、X射线衍射(XRD)研究所制备的图形化ZnO阵列形貌、结构等,并测试其场发射性能。研究结果表明,制备的图形化ZnO纳米枝是圆阵列,直径为330μm左右,纳米ZnO主干平均直径为400~500nm,发现主干上有一些精细的类似锥状的纳米量级微细枝结构,并且具有良好的场发射性能,开启场强为2.15V/μm,场增强因子为16 109。该图形化生长ZnO阵列阴极的方法是一种能较好改善材料场发射性能的方法,在场发射应用领域表现出较好的前景。     

ZnO-Ni壳核丝状阴极的制备及其场发射性能研究

采用水热法在金属镍(Ni)丝表面生长氧化锌(ZnO)纳米材料.通过改变生长条件,制备出花状、锥状、管状、棒状四种形貌的ZnO-Ni壳核丝状阴极.采用扫描电子显微镜(SEM)观察所制备丝状阴极的表面形貌,采用X射线衍射(XRD)分析仪进行物相分析,结果表明所生长的纳米ZnO具有(002)品面择优取向.测试比较了这四种形貌ZnO-Ni壳核丝状阴极的场发射性能,结果表明管状ZnO纳米材料能较好地改善阴极表面的微观形貌,提高了阴极的场增强效应.     

籽晶层热处理温度对ZnO纳米棒阵列性能的影响

以不同热处理温度下制备的ZnO籽晶层为基底,采用水热法生长ZnO纳米棒阵列,对制备得到的ZnO纳米棒阵列的相结构和微观形貌以及发光特性进行了表征,分析了籽晶层热处理温度对ZnO纳米棒阵列性能的影响机理,发现在籽晶层热处理温度为450℃时,生长得到的ZnO纳米棒阵列空间取向最优,发光性能最好。     

反应溅射CN薄膜的场发射特性

利用反应射频溅射方法在硅单晶衬底上沉积碳氮(CN)薄膜.原子力显微镜(AFM)研究结果表明,CN薄膜表面覆盖有纳米CN锥状物,所制备的CN薄膜具有良好的场发射特性,最大发射电流密度达到～10mA/cm2,并且未出现电流饱和现象.薄膜表面的CN纳米锥有利于薄膜的场发射,重复测量结果表明,CN薄膜的发射特性得到改善和提高.     

反应溅射CN薄膜的场发射特性

利用反应射频溅射方法在硅单晶衬底上沉积碳氮(CN)薄膜.原子力显微镜(AFM)研究结果表明,CN薄膜表面覆盖有纳米CN锥状物,所制备的CN薄膜具有良好的场发射特性,最大发射电流密度达到～10mA/cm2,并且未出现电流饱和现象.薄膜表面的CN纳米锥有利于薄膜的场发射,重复测量结果表明,CN薄膜的发射特性得到改善和提高.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺,并在这种图形化衬底上成功生长了图形化的ZnO纳米棒.场发射测试表明制备的ZnO纳米棒具有良好的场发射性能,即具有较低的开启电场和阈值电场,较高的发射点密度.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺,并在这种图形化衬底上成功生长了图形化的ZnO纳米棒.场发射测试表明制备的ZnO纳米棒具有良好的场发射性能,即具有较低的开启电场和阈值电场,较高的发射点密度.     

籽晶层退火温度对ZnO纳米棒形貌及发光特性的影响

以不同退火温度处理后的ZnO籽晶层为基底,采用水热法生长了ZnO纳米棒阵列。对制备得到的ZnO纳米棒阵列的形貌、结构以及发光特性进行了表征,分析了籽晶层的退火温度对ZnO纳米棒阵列的形貌及发光性质的影响,发现通过调节籽晶层的退火温度,可以控制ZnO纳米棒的大小及密度,并发现在经400℃退火后的籽晶层上生长的ZnO纳米棒阵列形貌最佳,发光性能最优。     

不同结构的一维纳米ZnO的制备及其性能研究

采用热蒸发法在不同的条件下制备出了阵列状和铅笔状的-维纳米ZnO.利用X射线衍射、扫描电子显微镜、场发射测试仪、光致发光谱对ZnO纳米材料的结晶质量、形貌及场发射性能进行了分析.阵列状氧化锌纳米结构c轴择优取向良好,铅笔状氧化锌纳米结构场发射性能良好.两种纳米结构的室温光致发光谱均显示出了强紫外发射峰和弱绿光发射峰.     

氧化锌场发射性能的研究进展

简述了以场致发射显示器(FED)为代表的平板显示技术的发展现状与趋势,重点介绍了氧化锌一维纳米材料作为场发射阴极的场发射性能与研究现状,指出了具有应用前景的氧化锌一维纳米结构所需要解决的难题。     

带电子聚焦的氧化锌场发射背光源

液晶显示需要低功耗、均匀度好的光源作为背光源。为了降低功耗,提高显示图像质量,未来的液晶显示需要实现对背光源进行时间与阵列调制。对比现有的液晶显示用背光源,研究制备了氧化锌场发射光源。该光源采用氧化锌纳米针作为场发射阴极,采用平面栅极作为门电极调制结构实现亮度的连续可调,通过带有氧化镁二次电子发射层的金属栅网对电子进行聚焦实现光源的均匀照度。实验结果表明,带电子聚焦的氧化锌场发射光源具有较低的开启场强(1.1V/μm),较小的电压调制区间(小于150V),较高的发光强度(大于1 000cd/m2),且基于电子聚焦结构的设计,实现了光源的均匀稳定照度,可以提高液晶显示的图像质量。带电子聚焦结构的氧化锌场发射光源,既可实现对发光的时间与阵列调制,同时能提高发光的均匀性,将可作为液晶显示的理想背光源。     

Morphological and spectroscopic studies on the vertically aligned zinc oxide nanorods grown on low and high temperature deposited seed layer

Vertically aligned zinc oxide nanorods were grown on low and high temperature deposited aluminium doped zinc oxide seed layer by hydrothermal method and annealed to improve crystallinity. The morphology of the seed layer and the grown nanorods were studied by field emission scanning electron microscopy characterization technique. The properties of the zinc oxide nanorods were analyzed using laser spectroscopic studies. Resonant Raman spectroscopy reveals the unique increase in the A₁(LO) mode of vibration with increase in count. The luminescence property of the nanorods was studied with photoluminescence spectrometer. The vertically aligned zinc oxide nanorods show, the very high band edge emission in the ultraviolet region of the electromagnetic spectrum.     

碳纳米球薄膜的场发射特性

利用微波等离子体化学气相沉积法,在Si(100)衬底上制备了碳纳米球薄膜。利用拉曼光谱和场发射扫描电子显微镜研究了薄膜的结构以及表面形貌,表明碳纳米球薄膜是由约2～3μm长、100nm宽的无定形碳纳米片相互缠绕、交织成球状而构成的。在高真空系统中测量了碳纳米球薄膜的场发射特性,结果表明,碳纳米球薄膜具有良好的场发射特性,阈值电场为3.1V/μm,当电场增加到10V/μm时,薄膜的场发射电流密度可达到60.7mA/cm2。通过三区域电场模型合理地解释了碳纳米球薄膜在低电场、中间电场和高电场区域的场发射特性。     

Synthesis of Tetrapodlike Zinc Oxide Nanostructures by Inductive Heating

The inductive heating method is used to synthesize regular tetrapodlike zinc oxide nanostructures on a glass substrate. The morphology of tetrapodlike ZnO nanostructures is investigated by scanning electron microscopy. It is found that the tetrapodlike ZnO structure fabricated by inductive heating is smaller than that fabricated by PVD. Therefore, more emission sites can be generated with the tetrapodlike ZnO structures obtained by inductive heating. The field-emission characteristics of ZnO nanostructures are also measured in this letter. The measurement results show that the tetrapodlike ZnO nanostructures obtained by the inductive heating method have low turn-on electric field and high emission current. Its field-emission performance is better than that of the tetrapod ZnO emitters obtained by PVD due to its good morphology and adhesion on substrate. Because ZnO nanostructures can grow directly on a glass substrate with the inductive heating method, it is very useful for the application in the field-emission display panel.      

Optical and thermal properties of precursor-controlled graphene–zinc nanocomposites

Graphene, a monolayer two dimensional carbon sheet can be utilized as a support to anchor functional nanomaterials to form novel nanocomposites for a variety of potential applications. We present an approach for the in situ preparation of graphene–zinc oxide nanocomposites through a reflux process in which either zinc acetate or zinc chloride can serve as precursors. The synthesized samples were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray analysis, ultraviolet–visible spectroscopy and thermogravimetry analysis (TGA–DSC) for structural, optical and thermal properties. It has been found that nanocomposites comprise of zinc oxide (ZnO) nanostructures deposited on graphene sheets, and the choice of zinc precursor has a deterministic influence on the morphology, structure and properties of the graphene–ZnO nanocomposites. In addition, the novel structure of zinc acetate based nanocomposite has induced improved absorption and thermal stability of the graphene/ZnO nanocomposite as compared to zinc chloride based nanocomposite and would be promising for future applications in nanotechnology.     

The preparation of oxygen-deficient ZnO nanorod arrays and their enhanced field emission

Vertical and uniform zinc oxide (ZnO) nanorod arrays (NRAs) with sharp tips were fabricated on Zn substrate by a straightforward hydrothermal method without the assistance of seed layer, template or surfactant. Whereafter, the as-synthesized ZnO NRAs were successfully doped with oxygen vacancies by sodium borohydride (NaBH₄) solution reduction, aiming to generate donor energy levels below the conduction band. More importantly, the doped concentration of oxygen vacancies could be effectively controlled by adjusting the reduction temperature, and we have ultimately achieved the purpose of controllable tailoring the energy band structure of ZnO NRAs. As with design, the oxygen-deficient ZnO NRAs present a lower turn-on field of 0.67 V/μm, higher field enhancement factor of 64601 and better field emission stability. Such excellent FE performance of the as-prepared emitter should originate from the optimization of geometry, the efficient electron transport, as well as the decreased work function.     

Influence of annealing temperature on field emission from tetrapod-shaped ZnO-whisker films obtained by screen printing

Tetrapod-shaped zinc oxide whisker-film emitters were fabricated on indium tin oxide glass substrates using a screen-printing method. The influence of annealing temperature on field emission of tetrapod-whisker ZnO-based emitters was investigated. X-ray diffraction and scanning electronic microscopy were applied to characterize the structure and the surface morphology of the deposited films. It was found that ZnO-based emitters annealed at 250 °C have the best field emission properties with the lowest turn-on field of 2.6 V/μm at a current density of 1 μA/cm², the lowest threshold field of 5.2 V/μm at a current density of 1 mA/cm² and high field emission enhancement factor of 4129. Moreover, films with homogeneous, fine and dense light spots with low emission current fluctuation of 1.7% were obtained from samples annealed at 250 °C.     

宽禁带氧化锌半导体薄膜的研究进展

氧化锌作为新一代化合物半导体,其禁带宽度对应紫外光的波长。氧化锌薄膜有望开发蓝光、蓝绿光、紫外光等多种发光器件,具有广阔的应用前景。重点介绍了氧化锌薄膜的研究进展以及存在的问题,并对氧化锌薄膜的未来进行了展望。