压敏电阻陶瓷材料的研究进展

详细介绍了目前国内外研究最多的低压压敏陶瓷材料(ZnO系、BaTiO3系、TiO2系、WO3系)、电容–压敏陶瓷材料(SrTiO3系、TiO2系)及高压–压敏陶瓷材料(ZnO系、SnO2系)等的基本配方、制备工艺、性能及主要应用等。还讨论了我国在压敏电阻器研究与生产方面所存在的问题及今后的研究方向。     

传送网控制平面的未来发展

ASON/GMPLS作为OTN、SDH、PTN等传送网的统一控制平面,成就了传送网的智能化。ASON/GMPLS控制平面未来将如何发展？     

基体偏压对反应磁控溅射ZrN/α-SiNx纳米多层薄膜结构及性能的影响

采用中频磁控溅射技术在3种偏压条件下(0、-80、-300V)于AISI 440C钢及单晶Si(100)基体表面制备了ZrN/α-SiNx纳米多层薄膜.通过高分辨透射电子显微镜(HRTEM)分析表征了各纳米多层薄膜微观组织结构,并通过纳米压入仪与真空球-盘摩擦试验机分别测试了各薄膜力学及真空摩擦学性能.重点研究了基体偏压对ZrN/α-SiNx纳米多层薄膜微观组织结构,进而对其力学及摩擦学性能的影响机制.结果表明:较低的基体偏压会导致纳米多层薄膜中ZrN层差的结晶状态,而较高的基体偏压则易于引起ZrN层与SiNx层层间界面的交混.上述两种薄膜组织及结构的变化均不利于该纳米多层薄膜力学及摩擦学性能的改善.在适宜的偏压条件下(-80 V),ZrN/d-SiNx薄膜呈现出具备良好层间界面的晶体/非晶体纳米多层结构,与其他偏压条件制备的纳米多层薄膜相比,该薄膜表现出更好的力学及摩擦学性能.     

低温沉积Ag-Cu薄膜的耐原子氧和摩擦学性能

采用多弧离子镀在低温(173 K)沉积了Ag-Cu薄膜,通过地面原子氧模拟试验机构考察了薄膜的耐原子氧性能,通过X射线衍射(XRD)、原子力显微镜(AFM)和球-盘摩擦试验机对薄膜结构、耐原子氧性能和摩擦学性能进行了表征,并与室温(300 K)及低温(173 K)沉积Ag薄膜进行了比较研究.结果表明:低温沉积Ag-Cu薄膜由面心立方结构的AgCu合金相和少量Ag或Cu组成,Cu元素合金和低温沉积可细化Ag薄膜的晶畴尺寸、提高其致密性,细密的薄膜结构有利于抑制原子氧对薄膜的攻击,因此低温沉积的Ag-Cu薄膜表现出较好的耐原子氧性能;磨损试验结果表明低温沉积的Ag-Cu薄膜表现出较好的耐磨性,这主要归因于其细密的薄膜结构和较高的膜-基结合强度,此外由于其耐原子氧性能的改善,低温沉积Ag-Cu薄膜在原子氧辐照前后磨损率的增加明显低于低温和室温沉积Ag薄膜.     

Variability on Raman Shift to Stress Coefficient of Porous Silicon

Porous silicon film is a capillary-like medium, which is able to reveal different meso-elastic modulus with porosity. During the preparation of porous silicon samples, the capillary force is a non-classic force related to the liquid evaporation which directly influences the evolution of residual stress. In this study, a non-linear relation of Raman shift to stress coefficient and the porosity is obtained from the elastic modulus measured with nano-indentation by Bellet et al. [J. Appl. Phys. 60 （1996） 3772] Dynamic capillarity during the drying process of porous silicon is investigated using micro-Raman spectroscopy, and the results reveal that the residual stress resulted from the capillarity increased rapidly. Indeed, the dynamic capillarity has a close relationship with a great deal of micro-pore structures of the porous silicon.     

Synthesis and room-temperature NO_2 gas sensing properties of a WO_3 nanowires/porous silicon hybrid structure

We report on the fabrication and performance of a room-temperature NO2 gas sensor based on a WO3 nanowires/porous silicon hybrid structure. The W18O49 nanowires are synthesized directly from a sputtered tungsten film on a porous silicon （PS） layer under heating in an argon atmosphere. After a carefully controlled annealing treatment, WO3 nanowires are obtained on the PS layer without losing the morphology. The morphology, phase structure, and crystallinity of the nanowires are investigated by using field emission scanning electron microscopy （FESEM）, X-ray diffractometer （XRD）, and high-resolution transmission electron microscopy （HRTEM）. Comparative gas sensing results indicate that the sensor based on the WO3 nanowires exhibits a much higher sensitivity than that based on the PS and pure WO3 nanowires in detecting NO2 gas at room temperature. The mechanism of the WO3 nanowires/PS hybrid structure in the NO2 sensing is explained in detail.     

氧化钨纳米线气敏传感器的制备及其室温NO_2敏感特性

纳米结构的氧化钨有高比表面积和气体吸附能力,在气体传感器领域得到了广泛研究.本文采用磁控溅射金属钨薄膜和两步热氧化工艺在二氧化硅衬底上生长出氧化钨纳米线.通过改变第二步氧化温度,研究退火温度对氧化钨纳米线气敏特性的影响.采用扫描电子显微镜、X射线衍射仪、X射线光电子能谱分析仪和透射射电子显微镜表征材料的微观特性和晶体结构,利用静态配气法测试气敏性能.研究结果表明,经过退火处理后氧化钨纳米线密度略微降低,300℃比400℃退火后的氧化钨结晶性差,对应的表面态含量多,有利于室温气体敏感性.测试NO_2的气敏性能,经过对比得出300℃退火温度下制备的氧化钨纳米线在室温下表现出较很好的气敏响应,对6 ppm(1 ppm=10~(-6))NO_2达到2.5,对检测极限0.5 ppm NO_2响应达1.37.氧化钨纳米线在室温下表现出反常的P型响应,是因为氧化钨纳米线表面被氧气吸附形成反型层,空穴取代电子成为主要载流子所致.     

氧化法结合快速热处理制备VOx薄膜及其性质研究

采用磁控溅射法在单晶Si〈100〉基底上沉积金属钒(V)薄膜,在高纯氧环境下快速热处理制备具有相变特性的氧化钒(VOx)薄膜.利用X射线衍射仪、X射线光电子能谱和扫描电子显微镜对薄膜结晶结构、薄膜中V的价态与组分及表面微观形貌进行分析,应用四探针测试方法和太赫兹时域频谱技术对样品的电学和光学特性进行测试.结果表明:在一定范围的快速热处理保温温度和保温时间下,都可以制备出具有热致相变特性的氧化钒薄膜,相变前后薄膜的方块电阻变化超过两个数量级,薄膜成分主要由V2O5和VO2混合组成,薄膜中V整体价态不因热处理条件改变而不同.在快速热处理条件范围内,500℃ 25 s左右条件下(中温区)制备出的氧化钒薄膜相变特性最佳,并且对THz波有一定的调制作用.     

Room temperature NO_2 gas sensing of Au-loaded tungsten oxide nanowires/porous silicon hybrid structure

In this work, we report an enhanced nitrogen dioxide(NO_2) gas sensor based on tungsten oxide(WO_3)nanowires/porous silicon(PS) decorated with gold(Au) nanoparticles. Au-loaded WO_3 nanowires with diameters of 10 nm–25 nm and lengths of 300 nm–500 nm are fabricated by the sputtering method on a porous silicon substrate. The high-resolution transmission electron microscopy(HRTEM) micrographs show that Au nanoparticles are uniformly distributed on the surfaces of WO_3 nanowires. The effect of the Au nanoparticles on the NO_2-sensing performance of WO_3 nanowires/porous silicon is investigated over a low concentration range of 0.2 ppm–5 ppm of NO_2 at room temperature(25℃). It is found that the 10-? Au-loaded WO_3 nanowires/porous silicon-based sensor possesses the highest gas response characteristic. The underlying mechanism of the enhanced sensing properties of the Au-loaded WO_3 nanowires/porous silicon is also discussed.     

多孔硅制备方法新进展及在微传感器中的应用

对近几年国内外出现的几种多孔硅制备方法和装置．特别是电化学方法如旋转电解槽法、电偶电流法和双电解槽法进行了详细的介绍，并对它们各自的优缺点进行比较和分析，认为电化学刻蚀技术因为其特殊的优势，将在以后的发展中得到更广泛的应用。多孔硅由于其独特的物理、化学和光学性能及技术优势，已经在微传感器领域得到广泛的应用。