钠钨青铜的制备与电子显微学表征

利用简单加热的方法合成了具有通道结构的钠钨青铜材料.通过X射线衍射学和电子显微学分析确定了三种产物分别是Na2 W4 O13、Na5 W14 O44和伪六角的Nax WO3+y.基于Na5 W14 O44和Nax WO3+y之间的结构关系,NaxWO3+y首次被确定为具有三斜结构的相(晶胞参数:aI I=0.7274 nm,bI I=0.7291 nm,cI I=11.031 nm,αI I=90.71°,βI I=90.69°,γI I=119.65°).研究结果为钠离子电池中新型电极材料的制备提供参考.     

Ca0.28Ba0.72Nb2O6晶体结构的高分辨电子显微学研究

Ca0.28Ba0.72Nb2O6（CBN28）晶体是一种新型的铁电材料，对其电光、压电、热电和光折变等性能的研究引起广泛的兴趣。X射线研究表明，Ca0.25Ba0.75Nb2O6（CBN25）结构上类似于四方钨青铜（TTB）晶体Sr0.5Ba0.5Nb2O6（SBN）。TTB晶体骨架由Nb-O八面体共顶点相连而成，沿c方向形成三角、四方和五角通道，不同有效半径的掺杂离子选择性地占据不同的通道。     

钾钨青铜材料中的W空位有序北大核心CSCD

本实验利用简单的加热方法合成具有通道结构六角钨青铜K_xWO_3,同时对其中存在的超结构进行原子尺度的扫描透射电子显微术分析。实验结果表明,六角钨青铜K_xWO_3中存在的超结构归因于单原子层内存在的W空位有序现象。同时发现,在电子束辐照的作用下,原子层内存在的W空位有序现象消失。该实验结果深化了对六角钨青铜K_xWO_3中存在的超结构的认识,从而为设计优异性能的钨青铜材料提供借鉴。     

铅锶钡铌系铁电性微晶玻璃的研制

主要对 Pb O- Sr O- Ba O- Nb2 O5 系铁电性微晶玻璃形成的温度制度作了研究。利用 X射线粉末衍射(XRD)图谱确证在一定配比及合理的热处理温度下 ,能够形成铁电性微晶玻璃。其主晶相为四方晶系钨青铜结构的 Pbn Bay Srz Nb1 0 O30 (0 相似文献   

低能离子束沉积制备GaAs:Gd的研究

对室温条件下用低能离子束沉积得到的GaAs∶Gd样品,借助X射线衍射(XRD)和高分辨X射线衍射(HR-XRD)进行了结构分析,结果表明没有出现新的衍射峰,并且摇摆曲线的形状与Gd的注入计量密切相关.运用X光电子能谱仪对比分析了Gd注入后,衬底中主要元素Ga2p和As3d的化学位移,以及不同计量的样品中注入的Gd4d芯能级束缚能的变化,并分析了铁磁性产生的可能原因.     

低能离子束沉积制备GaAs:Gd的研究

对室温条件下用低能离子束沉积得到的GaAs∶Gd样品,借助X射线衍射(XRD)和高分辨X射线衍射(HR-XRD)进行了结构分析,结果表明没有出现新的衍射峰,并且摇摆曲线的形状与Gd的注入计量密切相关.运用X光电子能谱仪对比分析了Gd注入后,衬底中主要元素Ga2p和As3d的化学位移,以及不同计量的样品中注入的Gd4d芯能级束缚能的变化,并分析了铁磁性产生的可能原因.     

铷蓝青铜及其钨掺杂样品的非线性电输运性质

用电解还原法生长出单晶晶体结构的铷蓝青铜及其系列钨掺杂样品,通过研究其电输运特性发现,纯样品及掺杂样品的电输运都呈相似的非线性特性,分别来源于阈值场以上电荷密度波滑移电导和杂质周围畸变引起的载流子的集体效应。     

制备工艺条件对薄膜微结构的影响

用不同的方法在石英玻璃,YAG晶体,K9玻璃和LiNbO3晶体等几种衬底上制备了ZrO2,HfO2和TiO2薄膜。HfO2薄膜利用电子束蒸发(EB)、离子束辅助(IAD)和双束离子束溅射(DIBS)三种方法沉积。对其中的一些样品进行了不同温度下的退火处理,对所有的样品进行X射线衍射(XRD)测试,以获得不同条件下得到的薄膜的晶相及晶粒尺寸等的微结构参数。实验结果表明,薄膜的晶相结构以及晶粒尺寸强烈地依赖于沉积过程的各种技术参数,如衬底的种类、沉积温度、沉积方法和退火温度。利用薄膜表面扩散以及薄膜成核长大热力学原理解释了不同技术条件下的晶相结构和晶粒尺寸不同的原因。     

退火温度对铁电薄膜钛酸锶钡的影响

用醋酸盐和钛酸酯为原料,采用改进的Sol-gel工艺在Pt/Ti/SiO2/Si基片上制备出Ba0.6Sr0.4TiO3(BST)铁电薄膜,然后进一步对薄膜进行退火实验:对(110)方向生长BST薄膜在550～750℃进行恒温退火.X射线衍射分析表明:退火温度在650℃以上时,BST薄膜转变为较为完整的ABO3型钙钛矿晶体结构,更高的退火温度将提高晶体的取向度.     

Annealing effects on the formation of semiconducting Mg2Si film using magnetron sputtering deposition

Semiconducting Mg2Si films were synthesized on silicon (11 1) substrates by magnetron sputtering deposition and subsequent annealing in an annealing furnace filled with argon gas,and the effects of heat treatment on the formation and microstructure of Mg2Si films were investigated.The structural and morphological properties were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM),respectively.The results show that the crystal quality of Mg2Si films depends strongly on the annealing temperature,the annealing time and the deposited magnesium film thickness.Annealing at 400 ℃ for 5 h is optimal for the preparation of Mg2Si film.XRD and SEM results show that magnesium silicide film with various orientations is formed on the silicon surface because of the interdiffusion and reaction of magnesium with substrate silicon atoms,and the evolution of surface features on growing films is very dependent on the annealing temperature and time.     

退火对磁控溅射法制备半导体Mg2Si薄膜的影响

通过磁控溅射和氩气氛围退火,在Si(111)衬底上制备环境友好半导体Mg2Si薄膜,并采用XRD和SEM研究了退火对Mg2Si薄膜形成和微结构的影响。结果表明Mg2Si薄膜的质量取决于退火温度、退火时间和沉积的薄膜厚度。制备Mg2Si薄膜,400℃退火5h是最优退火条件。XRD和SEM结构表明Mg2Si是通过沉积的Mg和Si衬底原子的相互扩散形成的。退火减少薄膜缺陷,也影响薄膜的表明粗糙度。     

退火时间对溶液法制备 Tips-Pentacene 电流传输特性的影响

通过测量p+Si/PEDOT∶PSS/Tips-PEN/Ag器件的J-V特性,研究了退火时间对溶液法制备Tips-PEN薄膜电流传输特性的影响。实验结果表明,在退火时间为2h和5h的条件下,随偏置电压的增加,双对数J-V曲线存在斜率依次为2,大于3以及2的不同区域,而在退火时间达到10h后,低电压下斜率为2的区域消失。根据空间电荷限制电流模型,分析了不同区域的电流传输机理,并提取了陷阱密度和空穴的迁移率。在退火时间为10h时,材料有最低的陷阱密度5.70×1018/cm3和最大的空穴迁移率1.68×10-4 cm2/(V·s),其在低偏置下传输特征的改变表明与溶剂残留有关的单一能级陷阱极大减小。     

铝青铜焊接热影响区的空蚀形貌特征

为了解铝青铜焊接热影响区(HAZ)的空蚀行为，对镍铝青铜焊接热影响区的空蚀形貌进行了扫描电镜(SEM)分析。结果表明：在空蚀初期，α相遭到选择性优先空蚀破坏；空蚀破坏呈现不均匀性，局部区域出现大的空蚀坑。热影响区空蚀破坏的机制是微坑的产生、长大、合并，进而形成裂纹，裂纹扩展最终导致失质。     

Dependence of porosity, charge recombination kinetics and photovoltaic performance on annealing condition of TiO2 films

Effect of annealing temperature, time of nanocrystalline TiO2 film on porosity, electron transport/recombination and photovoltaic performance on dyesensitized solar cell (DSSC) had been investigated in this article. Photocurrent density was slightly higher as annealing at 550℃ compared to those of annealing at 450℃ and 500℃ under the given annealing time of 60 min, which was correlated with the amount of adsorbed dye. Thermogravimetric analysis showed there was a more weight loss between 500℃ and 550℃, which revealed there were more sites for dye adsorption. Given the annealing temperature of 550℃, as annealing time varied from 60 to 90 and 120 min, results showed that the average size of pore and surface area decreased with longer annealing time, which deteriorated photocurrent density due to less dye loading. Electron diffusion rate remained almost unchanged regardless of annealing condition.However, electron recombination was influenced by annealing condition, it became slower with the increase of the annealing temperature under the given annealing time. In the contray, the electron recombination developed faster for the longer annealing time at a given annealing temperature. These results suggested that heat treatment of TiO2 film at 550℃ for 60 min in air would be the optimal annealing condition to achieve high efficiency DSSC.     

The effects of deposition temperature on the interfacial properties of SiH4 reduced blanket tungsten on TiN glue layer

Low pressure chemical vapor deposition tungsten films were deposited at various temperatures, using a WF₆−SiH₄−H₂ gas mixture. The impurity distribution at the W/TiN interface was investigated by Auger electron spectroscopy depth profiling. Some fluorine accumulation at the interface is observed when the tungsten is deposited below 300°C. However, above 300°C, no accumulation of fluorine could be observed. A result obtained from thermodynamic calculations using SOLGASMIX-PV suggests that this phenomenon is closely associated with the highly oxidized surface layer of TiN at the initial stage of deposition. The reaction of the gas mixture with the TiN surface layer seems to enhance the fluorine accumulation, which lowers the adherence of the interface and increases the contact resistance.     

Electron transport mechanism of tungsten trioxide powder thin film studied by investigating effect of annealing on resistivity

We report a new approach for improving the recharging and discharging speed of lithium ion batteries based on understanding of the electron conduction mechanism of tungsten trioxide (WO₃) powder thin films fabricated from nanoparticles and used in lithium ion battery electrodes. Resistivity measurements are carried out after annealing in N₂ or 5% O₂ + 95% N₂ ambient. Annealing in N₂ ambient decreases the resistivity owing to the increased number of oxygen vacancies in the WO₃ thin film. Fitting results obtained from the resistivity are used to propose the simultaneous existence of two types of electron conduction mechanism, band conduction and nearest-neighbor hopping (NNH) conduction, contributing to electron conduction in WO₃ thin films.     

钨浆料的稳定性研究

研究了用于质量分数为96%的氧化铝陶瓷的钨金属化配方以及相应的钨浆料生产工艺。为了提高钨浆料的稳定性,对浆料各组分的形貌、工艺进行了分析,发现粉体形貌、分散工艺、树脂性能对钨浆稳定性影响很大,提出了延长载体制备时间、提高载体黏度、选择粒度分布合理且比表面积较小的粉体等改善措施。结果表明,采用改善措施后在实际生产中取得了良好效果,制得的钨浆料印刷在陶瓷基片上于1 300℃烧结,平均封接强度达到39 MPa。