SiO2/聚酰亚胺/SiO2复合薄膜绝缘性能及基于聚酰亚胺复合薄膜的后栅型场致发射性能的研究

使用射频磁控溅射和化学溶液法制备了SiO2/聚酰亚胺(PI)/SiO2绝缘膜。分别使用X射线衍射、扫描电镜对薄膜结构和薄膜表面形貌进行了表征;利用超高阻微电流测试仪测试了SiO2/PI/SiO2复合绝缘膜漏电流和电压击穿特性;采用SiO2/PI/SiO2作为绝缘膜,制作了后栅型场致发射器件,使用场发射测试系统测试了器件的开启电压、发射电流以及发光亮度。结果表明:SiO2/PI/SiO2复合绝缘膜具有高的击穿电压和低的漏电流密度,后栅器件中栅极对阴极表面的电场强度调控作用明显,阳极电压为750V时,栅极开启电压为91 V,阳极电流可达384μA,栅极漏电流仅为59μA,器件最高亮度可达600 cd/m2。     

MgO纳米线的制备及其电子发射性能的研究

采用碳热还原-氧化法成功制备大小均匀的MgO纳米线,采用场致发射电子显微镜(FESEM)和X射线衍射(XRD)表征其形貌及晶体结构。采用丝网印刷将MgO纳米线转移到阴极电极,并将阴极电极与印刷有荧光粉的阳极电极组装成二级场致发射器件。场致电子发射测试表明MgO纳米线具有较好的电子发射特性:其阈值电场强度仅为3.82V/μm(1mA/cm2),最高电流密度达到2.68mA/cm2(4.01V/μm),发光亮度为1152cd/m2,4h内没有明显的衰减。MgO有望作为冷阴极材料在场致发射器件上得到应用。     

平栅极氧化锌场致发射电子源的制备及性能研究

采用传统的光刻技术制备平栅极场致发射阴极阵列,利用水热法原位合成ZnO发射源,并组装成平栅极ZnO场致发射电子源;利用光学显微镜、SEM和XRD表征其微观结构,分析ZnO发射源的生长机制,并结合场发射测试系统研究其发射特性。结果表明,ZnO发射源是平均直径为300nm的六方纤锌矿氧化锌纳米棒,且沉积在平栅极场致发射阴极阵列的阴极电极表面。场发射测试表明,平栅极ZnO场致发射电子源的发射特性完全由栅极控制。当阳极电压为2000V,器件的开启电压为150V;当栅极电压为275V时,发射电流可达345μA;在栅极电压为260V时,器件的发射电流波动范围为±5.5%左右,发光亮度高达750cd/m~2,表明该器件具有较好的场发射特性。     

平栅型双层膜阴极的脉冲电压处理及场致发射性能研究

采用脉冲电压法对平栅双层膜阴极进行处理,进一步提高其场致发射性能。采用磁控溅射法在平行栅电极上溅射氧化铋薄膜和氧化锡薄膜,并对薄膜进行AFM分析,通过场致发射测试结果表明,经过脉冲电压法处理后的平行栅双层膜阴极的发射性能,如亮度、均匀度等有了很大的提高,阳压为3 000 V,栅压为190 V,其腔体亮度可达462 cd/m2。平行栅双层膜阴极的脉冲电压处理可以有效改善阴极的场发射性能,为改善SED阴极结构及材料提供了一条有效的实验方法。     

衬底电极对SnO_2纳米材料场发射性能的影响

采用高温气相氧化法分别在Si、Au、Cr和不锈钢等不同的衬底上生长氧化锡（SnO2）纳米材料,并对SnO2的表面形貌进行表征和场致发射性能测试。研究结果表明,以Si、Au、Cr、不锈钢为衬底,其场致发射的开启电场分别为3.6、2.3、2.45、1.7V/μm。不锈钢衬底电极SnO2阴极的场致发射性能最好,硅衬底电极SnO2阴极的场发射能力最差。     

后栅型场发射显示器窜压现象的研究

提出后栅型场发射显示器(FED)测试过程中的窜压现象,解释该现象的产生原因。阴极电极侧壁场发射电子轰击栅极导致电压表示数发生变化。针对此问题设计一种具有沟槽状介质层结构的后栅型FED从而避免阴极电极侧壁的电子发射。采用全印刷技术制作场发射显示阵列。实验表明此器件具有良好的发射稳定性及栅压调控特性,有效杜绝窜压现象的发生。阳极电压为600 V,栅极电压在100~250 V范围内对阳极电流有良好的调控作用。     

常开型后栅极场致发射显示板工作特性的研究

常开型后栅极场致发射显示板是一种新型的场致发射器件.它直接利用阳极使阴极产生场致电子发射,而通过埋在阴极之下的栅极上施加负电压来阻止阴极产生场致电子发射来调制显示所需的图像.为了研究该场致发射显示板的阴极发射特性,本文采用有限元法对场致发射区域内的电场分布进行了模拟计算,用Fowler-Nordheim(F-N)公式计算了阴极表面的发射情况.并研究了阳极电压、阴极电压、阴调距、阴极宽度和阴极厚度等参数的改变对阴极发射特性和栅极调制能力的影响.计算结果显示阴极发射特性和栅极调制能力与上述电参数和结构参数关系密切,从而为优化设计这种显示器件提供了方向.     

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。     

圆锥形阴极真空微三极管的计算机模拟

利用有限元法对圆锥形场致发射阴极的真空微三极管进行了计算机模拟。改变真空微三极管的各项结构参数及阳极和栅极电压 ,得到一系列模拟数据。然后对模拟结果进行分析讨论 ,总结出圆锥形阴极有效发射、阳极电流与真空微三极管的结构尺寸、阳极电压和栅极电压之间的关系 ,对于真空微三极管的实际设计和制作有一定的参考价值     

圆锥形阴极真空微三极管的计算机模拟

利用有限元法对圆锥形场致发射阴极的真空微三极管进行了计算机模拟。改变真空微三极管的各项结构参数及阳极和栅极电压,得到一系列模拟数据。然后对模拟结果进行分析讨论,总结出圆锥形阴极有效发射、阳极电流与真空微三极管的结构尺寸、阳极电压和栅极电压之间的关系,对于真空微三极管的实际设计和制作有一定的参考价值。     

新型前栅场发射器件的研究

采用刻蚀型介质制作前栅场发射器件。该器件中阴栅结构的形成是利用刻蚀工艺刻蚀介质层,一次性实现栅孔和阴极电极的连通,最后利用电泳沉积工艺转移碳纳米管制备成阴极发射点阵。该工艺避免了对准或套印,使前栅场发射器件制作工艺更简单,降低了成本,更容易实现大面积制作。场发射测试表明当阳压在1500和2000 V时,栅压都能够有效地控制阴极的电子发射。     

Enhanced field-emission from SnO2:WO(2.72) nanowire heterostructures

The field-emission properties of SnO(2):WO(2.72) hierarchical nanowire heterostructure have been investigated. Nanoheterostructure consisting of SnO(2) nanowires as stem and WO(2.72) nanothorns as branches are synthesized in two steps by physical vapor deposition technique. Their field emission properties were recorded. A low turn-on field of ~0.82 V/μm (to draw an emission current density ~10 μA/cm(2)) is achieved along with stable emission for 4 h duration. The emission characteristic shows the SnO(2):WO(2.72) nanoheterostructures are extremely suitable for field-emission applications.     

Fabrication and device characterization of omega-shaped-gate ZnO nanowire field-effect transistors

Omega-shaped-gate (OSG) nanowire-based field effect transistors (FETs) have attracted a great deal of attention recently, because theoretical simulations predicted that they should have a higher device performance than nanowire-based FETs with other gate geometries. OSG FETs with channels composed of ZnO nanowires were successfully fabricated in this study using photolithographic processes. In the OSG FETs fabricated on oxidized Si substrates, the channels composed of ZnO nanowires with diameters of about 110 nm are coated with Al(2)O(3) using atomic layer deposition, which surrounds the channels and acts as a gate dielectric. About 80% of the surfaces of the nanowires coated with Al(2)O(3) are covered with the gate metal to form OSG FETs. A representative OSG FET fabricated in this study exhibits a mobility of 30.2 cm(2)/ (V s), a peak transconductance of 0.4 muS (V(g) = -2.2 V), and an I(on)/I(off) ratio of 10(7). To the best of our knowledge, the value of the I(on)/I(off) ratio obtained from this OSG FET is higher than that of any of the previously reported nanowire-based FETs. Its mobility, peak transconductance, and I(on)/I(off) ratio are remarkably enhanced by 3.5, 32, and 10(6) times, respectively, compared with a back-gate FET with the same ZnO nanowire channel as utilized in the OSG FET.     

电催化金属辅助化学刻蚀法制备硅纳米线/多孔硅复合结构

量子限制效应使硅纳米线具有良好的场致发射特性, 结合多孔硅的准弹道电子漂移模型可提高场发射器件的性能。传统的金属辅助化学刻蚀法制备硅纳米线的效率较低, 本研究在传统方法的基础上引入恒流源, 提出电催化金属辅助化学刻蚀法, 高效制备了硅纳米线/多孔硅复合结构。在外加30 mA恒定电流的条件下, 硅纳米线的平均制备速率可达308 nm/min, 较传统方法提升了173%。研究了AgNO₃浓度、刻蚀时间和刻蚀电流对复合结构形貌的影响规律; 测试了采用电催化金属辅助化学刻蚀法制备样品的场发射特性。结果显示样品的阈值场强为10.83 V/μm, 当场强为14.16 V/μm时, 电流密度为64 μA/cm²。     

Field-emission triode of low-temperature synthesized ZnO nanowires

A field-emission triode based on the low-temperature (75/spl deg/C) and hydrothermally synthesized single-crystalline zinc-oxide nanowires (ZnO NWs) grown on Si substrate with a silicon dioxide (SiO/sub 2/) insulator was fabricated for the controllable field-emission device application. Field-emission measurement reveals that the ZnO NWs fabricated on the Si substrate exhibit a good emission property with the turn-on electric field and threshold electric field (current density of 1 mA/cm/sup 2/) of 1.6 and 2.1 V//spl mu/m, respectively, with a field enhancement factor /spl beta/ of 3340. The field-emission properties of the ZnO NW-based triode exhibit the controllable characteristics. The well-controlled field-emission characteristics can be divided into three parts: gate leakage region, linear region, and saturation region. Therefore, this study provides a low-temperature field-emission triode fabrication process that is compatible with the Si-based microelectronic integration, and the field-emission measurements also reveal that the emission behavior can be well controlled by adopting the triode structure.     

氧化锡薄膜场致发射研究

利用直流磁控反应溅射法,制备氧化锡薄膜,利用扫描电镜等方法对氧化锡薄膜微观结构进行分析。在低真空下,对不同厚度的氧化锡薄膜进行场致发射测试,结果显示,在氧化锡薄膜厚度为60nm时,场致发射性能最佳,当电流密度为10μA/m2时,开启电压为4.5 V/μm,阴阳两极电场为7 V/μm时,有较佳的场发射密度,同时发光亮度达到2180 cd/m2,结果表明,氧化锡薄膜在场发射平板显示及真空电子器件方面具有较好的应用潜力。     

Synthesis, characterization and opto-electrical properties of ternary Zn2SnO4 nanowires

Ternary oxides have the potential to display better electrical and optical properties than the commonly fabricated binary oxides. In our experiments, Zn(2)SnO(4) (ZTO) nanowires were synthesized via thermal evaporation and vapor phase transport. The opto-electrical performance of the nanowires was investigated. An individual ZTO nanowire field-effect transistor was successfully fabricated for the first time and shows an on-off ratio of 10(4) and transconductance of 20.6 nS, which demonstrates the promising electronic performance of ZTO nanowire in an electrical device. Field emission experiments on ZTO nanowire film also indicate their potential application as a field emission electron source.     

Fabrication of reliable semiconductor nanowires by controlling crystalline structure

One-dimensional SnO(2) nanomaterials with wide bandgap characteristics are attractive for flexible and/or transparent displays and high-performance nano-electronics. In this study, the crystallinity of SnO(2) nanowires was regulated by controlling their growth temperatures. Moreover, the correlation of the crystallinity of nanowires with optical and electrical characteristics was analyzed. When SnO(2) nanowires were grown at temperatures below 900?°C, they showed various growth directions and abnormal discontinuity in their crystal structures. On the other hand, most nanowires grown at 950?°C exhibited a regular growth trend in the direction of [100]. In addition, the low temperature photoluminescence measurement revealed that the higher growth temperatures of nanowires gradually decreased the 500 nm peak rather than the 620 nm peak. The former peak is derived from the surface defect related to the shallow energy level and affects nanowire surface states. Owing to crystallinity and defects, the threshold voltage range (maximum-minimum) of SnO(2) nanowire transistors was 1.5 V at 850?°C, 1.1 V at 900?°C, and 0.5 V at 950?°C, with dispersion characteristics dramatically decreased. This study successfully demonstrated the effects of nanowire crystallinity on optical and electrical characteristics. It also suggested that the optical and electrical characteristics of nanowire transistors could be regulated by controlling their growth temperatures in the course of producing SnO(2) nanowires.