X射线干涉仪实现扫描探针显微镜样板线间距纳米测量

X射线干涉仪以非常稳定的单晶硅晶格作为长度单位 ,可以实现亚纳米精度的微位移测量。提出了将 X射线干涉仪和扫描隧道显微镜结合起来 ,利用单晶硅的晶格尺度测量扫描探针显微镜样板节距的技术方案 ,并进行了实验研究     

扫描隧道显微镜纳米云纹法的实验研究

提出了应用扫描隧道显微镜(STM)纳米云纹法测量面内位移的原理。测量中,把扫描隧道显微镜的探针扫描线作为参考栅,把物质原子晶格栅结构作为试件栅,对这两组栅线干涉形成的云纹进行了纳米级变形测量。对扫描隧道显微镜纳米云纹的形成原理及测量方法进行了详尽的讨论,并运用该方法对高定向裂解石墨(HOPG)的纳米级变形虚应变进行了测量研究,得到了随扫描范围变化的虚应变场,并与理论值进行了比较。     

X射线干涉仪实现扫描控针显微镜样板线间距纳米测量

X射线干涉仪以非常稳定的单晶硅晶格作为长度单位,可以实现亚纳米精度的微位移测量。提出了将X射线干涉仪和扫描隧道显微镜结合起来,利用单晶硅的晶格尺度测量扫描探针显微镜样板节距的技术方案,并进行了实验研究。     

扫描探针显微镜应用于材料纳米摩擦学研究的若干技术问题

扫描探针显微镜已经成为材料纳米摩擦学研究的主要工具之一,本文探讨了扫描探针显微镜应用于材料纳米摩擦学研究的若干测试技术问题,并用摩擦力显微镜对DLC薄膜的纳米摩擦学行为进行了研究.     

基于扫描隧道显微镜的原子电子云结构

本文简要介绍了扫描隧道显微镜的基本工作原理，展示了一些扫描样品（石墨和铜）的电子云图，在简要介绍量子力学关于原子电子云结构基本理论的基础上，通过理论上的电子云结构与扫描结果的比较，在一定程度上验证了量子力学关于原子电子云结构理论的正确性．     

扫描探针显微术与纳米科技

 扫描探针显微术（ＳｃａｎｎｉｎｇＰｒｏｂｅＭｉｃｒｏｓｃｏｐｙ,ＳＰＭ）是８０年代初发展起来的一类新型的表面研究新技术,其核心思想是利用探针尖端与表面原子间的不同种类的局域相互作用来测量表面原子结构和电子结构。它的出现使得纳米科技在近十年来得到了突飞猛进的发展。１．扫描探针显微术扫描探针显微术中最早研制成功的是扫描隧道显微镜（ＳｃａｎｎｉｎｇＴｕｎｎｅｌｉｎｇＭｉｃｒｏｓｃｏｐｙ,ＳＴＭ）,它是宾尼和罗雷尔于１９８１年发明的,二人１９８６年因此被授予诺贝尔物理奖。     

用扫描隧道显微镜操纵Cu亚表面自间隙原子

在超高真空环境下使用扫描隧道显微镜研究了吸附有双甘氨肽分子的Cu(001)表面.在一定的 偏压条件下，针尖在该表面扫描后会形成纳米尺度的Cu团簇，这些团簇可以根据意愿排列成 字母或图形.团簇的高度同偏压、隧道电流以及时间等条件有密切关系.在室温下可以稳定存 在的团簇为制造纳米器件提供了技术上的可能性.实验结果表明，形成团簇的Cu原子不是来 自Cu衬底表面或是针尖.化学吸附在Cu表面的双甘氨肽分子，受到隧道电场的作用会在Cu表 面形成张应变场，Cu亚表面自间隙原子在张应变场作用下迁移到表面是形成团簇的原因. 关键词： 扫描隧道显微镜 纳米尺度Cu团簇 自间隙原子     

扫描探针显微镜的基础知识

 本世纪80年代初,扫描探针显微镜(SPM)对硅表面第一次的实空间成象使整个世界为之震惊,现在扫描探针显微镜已在各行各业获得了广泛的应用,包括表面科学,常规表面粗糙度的分析及表面从原子级到微米级凸起的三维成象。     

扫描隧道显微镜针尖调制的薄膜表面的原子扩散

采用原子尺度的模拟方法,探讨了在零偏压下扫描隧道显微镜(STM)针尖调制的金属表面岛上原子运动及岛边的层间质量输运. 研究结果显示STM的移动对岛上及岛边的原子扩散有重要的影响. 针尖与吸附原子的交互作用及岛和基体中强的形状变化影响了岛上吸附原子的跳跃扩散及岛边的跳下扩散和交换扩散过程. 研究发现,通过调节针尖与基体的垂直距离及针尖与吸附原子的水平距离,可以降低岛上吸附原子的跳跃扩散能垒及岛边的跳下扩散和交换扩散能垒,从而实现薄膜由三维生长模式向二维生长模式的转变. 关键词： 扫描隧道显微镜 原子运动 质量输运     

用扫描热显微镜测量微小区域热导性质的探讨

随着高新技术的迅速发展,许多研究对象已进入亚微米和纳米范畴。在对这些对象的热性能和热可靠性的研究中,亚微米尺度的热物性测量已成为关键技术之一。例如：在微电子、微电子机械系统（MEMS）领域中,已使用纳米量级厚度的材质和做出纳米尺度线宽的器件。在材料科学、生物学、医学和化学等许多领域,高空间分辨率下的热物性测量也具有重要意义。本文经过实验;初步用扫描热显微镜判定了微小区域材料热导性质的差别,并从理论上探讨了用该仪器测量微小区域热导性质的方法原理。     

Single atomic manipulation and writing with scanning tunnelling microscopy at low temperatures

In the work reported in this paper,we have used a low-temperature scanning tunnelling microscope (LT-STM) system to manipulate accurately single atoms.We show how we can use a LT-STM to image and modify a bulk Ag(111) surface and manipulate Ag atoms from substrate and evaporated adsorbates on Ag(111) substrates.We present a synergistic combination of SM-induced modification and ordered arrays of nanometre-scale structures.In particular,we demonstrate the ability to modify Ag atomic nanometre structures on the Ag(111) substrate,and some English letters and a Chinese character can be written by single Ag atoms coming from the substrate and evaporated adsorbates on Ag(111),In this way ,we supply an effective basis to explore the fundamental physical properties of a nanometre structure and to develop nanotechnology with a bottom-up approach,     

发光隧道结表面粗糙度的隧道显微镜研究

本文报道用扫描隧道显微镜(STM)在空气中观测淀积在100nm厚的CaF_2薄膜上的Al-Al_2O_3-Au发光隧道结表面的研究成果.在观测中首次发现结表面呈现出横向相关长度分别为30～70nm和3～5nm的两种粗糙度;横向相关长度小的粗糙度被横向相关长度大的所调制.这种横向相关长度为3～5nm的表面粗糙度的存在与Laks和Mills预期的表面随机粗糙隧道结发光理论值一致.     

Characterization of coating probe with Ti-DLC for electrical scanning probe microscope

In electrical scanning probe microscope (ESPM) applications, the wear and conductivity of the probe are undoubtedly serious concerns since they affect the integrity of the measurements. This study investigates the characterization of Ti doped diamond-like-carbon (DLC) as coating material on a silicon cantilever for ESPM. We deposited a layer of Ti-DLC thin film on the surface of Si cantilever by magnetron sputtering. The morphology and composition of the Ti-DLC films were characterized by scanning electron microscopy and Raman spectroscopy, respectively. We also compared the wear resistance, electric conductivity and scanning image quality of the Ti-DLC-coated probes with those of commercially available conductive probes. The results showed that the electric conductivity and the scanning image quality of the Ti-DLC-coated probes were the same as the commercial conductive probes, while the wear resistance and service life was significantly better.     

Adsorption geometry of glycine on Cu（001） determined with low—energy electron diffraction and scanning tunnelling microscopy

Using low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) it has been found that glycine molecules adsorbed on Cu(001) can form but only the (2×4) and c(2×4) superstructures. On the basis of the missing LEED spots of the surface, it has been concluded that: each (2×4) unit cell consists of two molecules, one being the mirror image of the other; the C－C axis of both molecules lies in the mirror plane of the Cu substrate without a significant shift and twist from the plane; and the two O atoms of the carboxylate group of both molecules locate at the same height level without significant buckling. According to these conclusions, a structural model has been proposed for the (2×4) superstructure (a model for the c(2×4) superstructure already exists). We argue that the (2×4) and c(2×4) superstructures must have similar specific surface free energy, that their hydrogen bonds must be of N-H-O_II type, and that their local adsorption geometry must be similar or even the same. The advantage of combining STM with LEED to determine surface structures is clearly demonstrated.     

Direct measurements of conductivity and mobility in millimeter-sized single-crystalline graphene via van der Pauw geometry

We report the direct measurements of conductivity and mobility in millimeter-sized single-crystalline graphene on SiO_2/Si via van der Pauw geometry by using a home-designed four-probe scanning tunneling microscope(4P-STM). The gate-tunable conductivity and mobility are extracted from standard van der Pauw resistance measurements where the four STM probes contact the four peripheries of hexagonal graphene flakes, respectively. The high homogeneity of transport properties of the single-crystalline graphene flake is confirmed by comparing the extracted conductivities and mobilities from three setups with different geometry factors. Our studies provide a reliable solution for directly evaluating the entire electrical properties of graphene in a non-invasive way and could be extended to characterizing other two-dimensional materials.     

钒氧酞菁(VOPc)与钒酞菁(VPc)分子的扫描隧道显微镜图像模拟

利用第一性原理方法模拟了自由钒氧酞菁(VOPc)和钒酞菁(VPc)分子的扫描隧道显微镜(STM)图像,与实验观察结果相当符合.理论STM图像都显示出亚分子内结构,外围呈四叶状.其主要差异表现在VOPc分子中心处的钒氧离子在STM图像中为一空洞,而在VPc分子的STM图像中钒离子为突起的亮斑.通过分析VOPc和VPc分子的电子结构,对模拟结果给出自洽的理论解释.造成两者图像显著不同的物理原因是VPc分子在费米能级附近有明显含dz2成分的分子轨道,导致钒离子在STM图像中央为突起的亮斑.而在VOPc分子中dz2分态密度峰位由于氧原子的加入使之远离费米能级,使STM不能“看到”VOPc分子中钒氧离子. 关键词： 钒氧酞菁 钒酞菁 STM图像模拟 电子结构     

Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.     

基于微芯片的透射电子显微镜的低温纳米精度电子束刻蚀与原位电学输运性质测量

利用微芯片制备技术制备了带有电极的原位电学薄膜芯片,并结合自制的原位透射电镜样品台,实现了低温下透射电子显微镜聚焦电子束对InAs纳米线的精细刻蚀以及不同温度下的原位电学性能测量.研究发现,随着刻蚀区域截面积的减小,纳米线的电导率也随之减小.当纳米线的截面积从大于10000 nm2刻蚀至约800 nm2时,纳米线电导的减小速率与截面积的减小具有线性关系.同时利用低温聚焦电子束刻蚀,在InAs纳米线上原位制备了一个10 nm的纳米点,并在77与300 K下对该纳米点进行了电学性能测量.通过测量发现在77 K时出现库仑阻塞效应,发生了电子隧穿现象;而300 K时,热扰动提供的能量使这种现象消失.     

Compressibility determination by electrical resistance measurement: a universal method for both crystalline and amorphous solids

A new method is introduced for investigating the compressibility of solids under high pressure by in situ electrical resistance measurement of a manganin wire, which is wrapped around the sample. This method does not rely on the lattice parameters measurement, and the continuous volume change of the sample versus pressure can be obtained. Therefore, it is convenient to look at the compressibility of solids, especially for the X-ray diffraction amorphous materials. The I–II and II–III phase transition of Bi accompanying with volume change of 4.5% and 3.5% has been detected using the method, respectively, while the volume change for the phase transition of Tl occurring at 3.67 GPa is determined as 0.5%. The fit of the third-order Birch–Murnaghan equation of state to our data yields a zero-pressure bulk modulus K ₀=28.98±0.03 GPa for NaCl and 6.97±0.02 GPa for amorphous red phosphorus.