高温超导体Bi2Sr2CaCu2O8+δ单晶解理面的AFM研究

用ＡＦＭ在室温和大气下对高温超导体Ｂｉ２Ｓｒ２ＣａＣｕ２Ｏ８＋δ（Ｂｉ２２１２）单晶解理面的形貌和结构进行了系统的研究。观测到解理面绝大部分是原子级平滑的晶面。在晶面的边缘观测到高度为结构单元（ｃ／２）整倍数的台阶，这与该晶体是以层状模式生长的机制相一致的。进而证明了解理位置和解理分布。在解理面的局部区域，观测到高度为１．２５ｎｍ，面积约为０．０５μｍ２的平台。Ｘ－射线微区分析证明这些小平台正是在Ｂｉ２２１２单晶生长中常存在的少量Ｂｉ２２０１相。我们的研究表明ＡＦＭ不但在研究高温超导体单晶的形貌特征方面有重要用途，而且在对晶体的质量进行分析和结构特征研究中也有重要应用。     

4.2K低温扫描隧道显微镜的研制及 2H-NbSe2中电荷密度波的观测

We describe a home-built low temperature scanning tunneling microscope (LT-STM) which can work at room temperature,77K and 4.2K.The LT-STM main body is made of machinable glass ceramic (MACOR) which provides highly mechnical rigidity and thermal stability.The main body includes also a piezo linear step motor which realizes automatically the precise aproach of tip to sample.The LT-STM system are also consisted of a two-stage vibration isolation consisting of spring suspensaion and an air table,a 2×10^-4Pa oil-free high vacuum pumping line,a 6 tesla superconducting magnet,a helium Dewar,electronic control system and windows interfaced STM software.With this LT-STM atomically resolved images of HOPG were obtained at both room temperature and 4.3K.We have also observed a high quality atomic modulation and the charge density wave modulation and possiblly the periodic lattice distortion in crystal 2H-NbSe₂.We have also measured the tunneling spectroscopies of high temperature superconductor Bi2212 at 4.3K by using this home-built LT-STM.     

纳米结构可重入扫描隧道显微镜系统的研制

本文简介我们最近研制成功的超高真空（ＵＨＶ）扫描隧道显微镜（ＳＴＭ）系统。该系统由于同时安装有扫描电子显微镜（ＳＥＭ），可以使ＳＴＭ的针尖在ＳＥＭ的引导下移到样品表面上任一感兴趣的地方去研究那时的纳米细节，从而使它的ＳＴＭ具有纳米结构可重入性。该系统还有一些特有的样品制备功能，可用于许多有价值的研究 。     

溶液中细胞色素b6f的原子力显微镜和扫描隧道显微镜观测

本文用原子力显微镜(atomic force microscope,AFM)和扫描隧道显微镜(scanning tunneling microscope,STM)在Tricine-NaOH-OG缓冲溶液中研究了细胞色素b6f(Cytochrome b6f,Cyt b6f)在固体表面上的吸附形态。首先用AFM观察了吸附在云母表面上的cyt b6f复合体,观察到了分散较好的蛋白质颗粒。进一步用高分辨率的电化学STM(EC-STM)观察了吸附在Au(111)表面上的cyt b6f分子,在浓度较低时发现了其二聚体的吸附形态,而在浓度较高时cyt b6f分子在Au(111)表面聚集成薄膜。     

(Bi,Pb)2Sr2CaCu2O8薄膜的激光感生电压效应

采用紫外脉冲激光沉积技术和高低温沉积工艺,在LaAlO3(100)平衬底及倾斜衬底上成功制备了c轴取向的(Bi,Pb)2Sr2CaCu2O8[(Bi,Pb)-2212]薄膜;研究了在倾斜LaAlO3(100)单晶衬底上生长的(Bi,Pb)-2212薄膜激光感生热电电压信号与沉积条件及入射激光能量的关系。为避免(Bi,Pb)-2212薄膜被激光剥蚀或蒸发,还初步研究了MgO保护层对(Bi,Pb)-2212薄膜激光感生电压信号的作用,结果表明MgO层能够显著增强激光感生热电电压效应。     

Cu－Zn－Al合金中贝氏体的扫描隧道显微镜分析

本文用扫描隧道显微镜（ＳＴＭ）在天气中研究了Ｃｕ－２７．２ｗｔ．％Ｚｎ－４．７ｗｔ．％Ａｌ合金中的贝氏体的精细结构，并与透射电镜（ＴＥＭ）及扫描电镜（ＳＥＭ）下的形态进行了比较，发现Ｃｕ－Ｚｎ－Ａｌ合金中贝氏体是由亚片条或亚单元组成，亚单元由超亚单元构成，进而为贝氏体相变机制的再认识提供了重要的实验基础，并在此基础上提出Ｃｕ－Ｚｎ－Ａｌ合金中贝氏体的形成模型。     

低温烧结BaO-Nd2O3-TiO2陶瓷介质材料的研制

采用固相法制备了BaO-Nd2O3-TiO2( BNT)陶瓷,研究了Bi2O3-SiO2-ZnO-CaO( BSZC)玻璃添加量对所制BNT陶瓷介电性能的影响.结果表明:添加质量分数7％～9％的BSZC玻璃,可使BNT陶瓷在960℃下烧结致密,匹配10Pd/90Ag内电极,获得相对介电常数εr≈88,介质损耗tanδ=...     

Ba6-3xNd8+2xTi18O54陶瓷的微波合成及低温烧结

采用微波加热法于1 100℃保温30 min(升温速率为20℃/min)合成Ba6-3xNd8+2xTi18O54(x=0.30～0.75,BNT)陶瓷粉末,再添加质量分数45％的B2O3-SiO2-CaO-MgO( BM)玻璃,在马弗炉中于900℃烧结2h制得BNT陶瓷.研究了所制陶瓷的微观结构及性能.结果表明:微波...     

扫描切变力/近场光学显微镜研制及应用

在发展光纤探针制备和探针与样品近场间距非光学控制等关键技术基础上，我们研制成能与倒置光学显微镜联合使用的扫描切变力／近场光学显微镜，并具有反射和透射等工作模式以及能在溶液环境中工作。利用这套系统，获得了多种样品的表面形貌和近场光学图像以及细胞内的荧光光谱。本文将对该系统和有关实验结果作简要介绍。     

The application of the scanning electron microscope to the development of high-reliability semiconductor products

Examples are given which illustrate the wide range of applicability of the scanning electron microscope to the processing of high reliability semiconductor products. The three areas selected for presentation are devitrifying solder glass seals for hermetic packages, voltage contrast examination of biased integrated circuits, and metallization corrosion problems encountered in processing technology. The scanning electron microscope gave useful information quickly, and, in some cases, it gave answers that other methods were unable to supply.     

二氧化硅超薄膜的扫描隧道显微镜和扫描隧道谱研究

用超高真空热氧化方法在Si(111)清洁衬底上生长了二氧化硅超薄膜，并利用超高真空扫描隧道显微镜和扫描隧道谱技术对超薄膜的表面形貌和局域电学特性进行了研究。结果显示，在超薄范围二氧化硅呈层状生长，不同层的微分电导谱所测禁带宽度差别可以达到约3eV，形貌对二氧化硅带宽的影响小于膜厚的影响。     

Pyroelectric properties of AlN wide-gap semiconductor in the temperature range of 4.2–300 K

The results of measurements of AlN polarization in the range of 4.3–300 K are presented. These results are used for calculating the pyroelectric coefficients as a function of temperature. The experiment was carried out both with an original sample grown from gas phase in nitrogen atmosphere at T ∼ 2400 K and with the sample subjected to external electric action in a field of different polarity. The sample polarization at T = 4.2 K results in a radical modification of the polar state of real AlN sample: due to the structural defects, ferroelectric ordering arises and the total sample polarization dependent on T increases by an order of magnitude. First of all, the revealed anomalies are related to the occurrence of oxygen in the crystalline structure resulting in considerable deformations of coordination tetrahedra in the wurtzite structure. The process of replacement of the nitrogen vacancies by oppositely charged oxygen ions also leads to changing the dipolemoment orientation for the coordination tetrahedra in the structure instead of changing only their magnitudes. The ferroelectric ordering “in pure form” exists in this AlN sample only below T ≈ 80 K.     

Measurements of near millimeter wave atmospheric attenuation in the temperature range 259K to 282K

Field measurements of absorption of near millimetre waves by the atmosphere at temperatures below 280°K have confirmed that there is an additional absorption component characterised by a much larger temperature exponent than can be attributed to water dimers in equilibrium.     

扫描力显微镜中的点衍射干涉现象及其应用

本文论述了扫描力显微镜中的点衍射干涉现象,论证了硅微探针可以作为后向点衍射板并用于检测微探针变位的光学原理。根据这一原理设计了一种新型灵巧的扫描力显微镜,它具有量争孤抗干扰稳定优质的光电信号,理论分析及实时表明,该扫描力显微镜具有０．０１ｎｍ的纵向分辨率,５ｎｍ左右的横向分辨率。     

STM中各种金属针尖／基底组合下的蒸发场强计算

稍前通过引入有效结合能的概念,本文作者重新建立了扫描隧道显微镜的蒸发场强公式,并计算了若干同种金属针尖与金属基底组合下的蒸发场强。本文进一步给出了更多的计算实例,特别是重点讨论了异种金属针尖与金属基底组合下的蒸发场强计算。为了确定不同针尖样品间距时的有效结合能,本文提出了一个普适函数,来描述吸附原子离金属基底不同距离时的原子势能曲线。     

Measurement of very low tunneling current density inSiO2 using the floating-gate technique

The floating-gate technique for measuring extremely low gate currents has been adapted to the measurement of Fowler-Nordheim tunneling currents in metal-oxide-semiconductor (MOS) capacitors. Using a special structure consisting of an MOS capacitor and a monitor transistor sharing a common-gate electrode, it has proved possible to measure tunneling current densities as low as 2×10^-13 A/cm². The Fowler-Nordheim tunneling relationship was found to be obeyed over the entire measurable range of current density     

二氧化硅微球的扫描电镜测长及形貌观察条件

本文用日立S-4800型冷场发射扫描电镜对不同粒径二氧化硅微球进行测长研究及形貌观察,针对二氧化硅材料特性和工作目标,使用多种测试条件,通过结果对比,分别获得测定二氧化硅微球直径和进行形貌观察的适宜条件.