原子力显微术

本文首先介绍了原子力显微术的基本理论，其次讨论了原子力显微镜的结构原理，主要报导了一台我们研制的使用光学偏转法检测的原子力显微镜及仪器性能，仪器测试的结果表明我们这台原子力显微镜获得了原子分辨率，最后给出使用这台显微镜的首批实验结果。     

Thermoacoustic Emission from Carbon Nanotubes Imaged by Atomic Force Microscopy

The thermoacoustic effect of isolated single‐wall carbon nanotubes aligned between electrodes is experimentally observed for the first time by imaging the emitted acoustic wave using an atomic force microscopy‐based technique specifically developed for the task. The capability of such a technique for single‐point thermoacoustic measurements is first verified on carbon nanotubes layers with two electrodes for injecting alternate electric current. The technique is then demonstrated to allow the acquisition, simultaneously with the topography, of images reflecting the pressure of the acoustic wave at fixed distance from the sample. Such a capability is used to collect images reflecting the amplitude of acoustic waves generated by isolated nanotubes and nanotube bundles by the thermoacoustic effect.     

Artifacts in Atomic Force Microscopy

The origin of artifacts in atomic force microscopy is discussed. They are classified by basic distinct features. Various solutions to this problem are suggested using the literature data. Metrological issues of the problem are touched upon.     

AFM 在纳米结构加工中的应用研究

文中阐述了基于自行研制的原子力显微镜(AFM)的纳米刻蚀加工方法，研究了针尖上的载荷大小和扫描次数对加工深度的影响，利用AFM的微探针在氧化铝(Al2O3)材料表面加工出纳米结构，验证了该加工方法的可行性。实验结果表明基于AFM的纳米刻蚀技术可作为加工纳米器件的重要手段。     

原子力显微轮廓仪系统的研究

研制了原子力显微镜（AFM）轮廓仪,介绍了AFM轮廓仪的基本原理和系统设计,并展示了多孔Al2O3薄膜、MgAl2O4薄膜和TiN薄膜的表面轮廓图。跟普通光学轮廓仪相比,该系统不需要进行复杂的光路调整,避免了光学元器件带来的误差,且工作行程不受光学孔径的制约,具有操作简单、抗干扰能力强和工作行程大的优点。实验表明,该系统具有良好的重复性、稳定性,横向分辨率为1μm,纵向分辨率为1nm。     

Atomic Force Microscopy Local Oxidation of GeO Thin Films

Semiconductors - Metastable germanium monoxide (GeO) thin-insulating films have been investigated as a new promising material for atomic force microscope (AFM) oxidation lithography. The kinetics...     

原子力显微镜针尖同接触面的纳米压痕粘着力

建立了原子力显微镜(AFM)针尖同接触面的纳米压痕物理模型;根据Hamaker三个假设和Lennard-Jones 势理论,利用连续方法推导出针尖同接触面的纳米压痕粘着力表达式.针对Hamaker常数实验值受环境影响较大,给Hamaker常数的具体应用产生困难的问题,从Lifshitz理论,得出Hamaker常数的近似表达式,并计算了Au、Cu、Al、Ag、Hg的Hamaker常数.计算结果同有关文献的实验结果符合,从而为微机械中广泛存在的纳米接触、"微碰"现象研究提供理论基础.     

原子力显微镜针尖同接触面的纳米压痕粘着力

建立了原子力显微镜(AFM)针尖同接触面的纳米压痕物理模型;根据Hamaker三个假设和Lennard-Jones 势理论,利用连续方法推导出针尖同接触面的纳米压痕粘着力表达式.针对Hamaker常数实验值受环境影响较大,给Hamaker常数的具体应用产生困难的问题,从Lifshitz理论,得出Hamaker常数的近似表达式,并计算了Au、Cu、Al、Ag、Hg的Hamaker常数.计算结果同有关文献的实验结果符合,从而为微机械中广泛存在的纳米接触、"微碰"现象研究提供理论基础.     

基于原子力显微镜的微桥机械特性测量

研究了基于原子力显微镜(AFM)的微桥机械特性的测量方法。通过微机电系统(MEMS)技术制备了可用静电力驱动进行机械振动的金属微桥。利用一套改进的商用AFM实验装置对测量方法进行了优化,并对微桥的共振频率进行了测量,所得实验结果与理论估算和仿真计算的结果基本一致。基于AFM的微桥机械特性的测量具有精度高和容易实现的特点,可作为测量平台扩展用于薄膜材料或微量液体的内耗、粘弹等性质的表征。     

Sensor Referenced Real-Time Videolization of Atomic Force Microscopy for Nanomanipulations

The main problem of atomic force microscopy (AFM)-based nanomanipulation is the lack of real-time visual feedback. Although this problem has been partially solved by virtual reality technology, the faulty display caused by random drift and modeling errors in the virtual reality interface are still limiting the efficiency of the AFM-based nanomanipulation. Random drift aroused from an uncontrolled manipulation environment generates a position error between the manipulation coordinate and the true environment. Modeling errors due to the uncertainties of the nanoenvironment often result in displaying a wrong position of the object. Since there is no feedback to check the validity of the display, the faulty display cannot be detected in real time and leads to a failed manipulation. In this paper, a real-time fault detection and correction (RFDC) method is proposed to solve these problems by using the AFM tip as an end effector as well as a force sensor during manipulation. Based on the interaction force measured from the AFM tip, the validity of the visual feedback is monitored in real time by the developed Kalman filter. Once the faulty display is detected, it can be corrected online through a quick local scan without interrupting manipulation. In this way, the visual feedback keeps consistent with the true environment changes during manipulation, which makes it possible for several operations to finish without an image scan in between. The theoretical study and the implementation of the RFDC method are elaborated. Experiments of manipulating nanomaterials including nanoparticles and nanorods have been carried out to demonstrate its effectiveness and efficiency.     

Characterization of Geoinspired and Synthetic Chrysotile Nanotubes by Atomic Force Microscopy and Transmission Electron Microscopy

Geoinspired synthetic chrysotile nanotubes both stoichiometric and 0.67 wt % Fe doped were characterized by transmission electron microscopy and electron diffraction. Bending tests of the synthetic chrysotile nanotubes were performed using the atomic force microscope. The nanotubes were found to exhibit elastic behaviour at small deformations (below ca. 20 nm). Young's modulus values of (159 ± 125) GPa and (279 ± 260) GPa were obtained from the force‐deflection curves using the bending equation for a clamped beam under a concentrated load, for the stoichiometric and the Fe doped chrysotile nanotubes, respectively. The structural modifications induced by Fe doping altered the mechanical properties, with an apparent dependence of the latter on the number of constituting walls of the nanotubes.     

Photopicking: In Situ Approach for Site‐Specific Attachment of Single Multiprotein Nanoparticles to Atomic Force Microscopy Tips

Ligand–receptor interactions are fundamental in life sciences and include hormone–receptor, protein–protein, pathogen–host, and cell–cell interactions, among others. Atomic force microscopy (AFM) proved to be invaluable for scrutinizing ligand–receptor interactions at the single molecular level. Basically, a ligand is attached to the AFM tip while its cognate receptor is immobilized on a surface or vice versa, and interactions are studied following triggered ligand–receptor binding. However, with rising biological complexity it becomes increasingly challenging to attach a single intact biomolecule to the tip and ensure interaction‐specific orientation. This study presents a novel strategy of inducible in situ tip functionalization with complex multiprotein nanoparticles exemplified by viral capsids, termed photopicking. It ensures a firm attachment of single 125 nm large capsids to the tip. Specific orientation is attained by weak immunosorption of capsids to the substrate and strong photoinducible covalent cross‐linking to the tip. Validation of the tip functionalization success is immediate in situ. The versatility of the strategy is further demonstrated on 20–60 nm large amino‐modified nanoparticles. In conclusion, considering the size range of the tested biomolecules, the presented strategy is applicable to viruses, viral particles, cellular organelles, multiprotein ligands/receptors, and therapeutic nanoparticles, among others. It therefore opens up exciting new avenues in broad biomedical research fields.     

STM光纤探针的研制

以普通的石英光纤为材料运用腐蚀－熔拉－腐蚀复合的方法制备出光纤探针，而后在针尖表面镀上一层数十nm厚的金属膜。达到导电性，使其能传导隧道电镜，并在STM上取得了理想的测试结果。     

基于AFM的微纳米结构力学特性测量

原子力显微镜（ＡＦＭ）以其优异的特性不仅在微米、纳米的范围内获取图象。同时可以获取针尖与样品之间的作用力,为研究样品的力学性能提供了新思路。对ＡＦＭ在力学测量上的原理和应用进行了综述,并提出基于ＡＦＭ的生物样品的力学测量的新方法。     

用原子力显微镜和扫描电镜研究GaN外延层中的位错腐蚀坑

用原子力显微镜和扫描电镜相结合的方法表征了KOH腐蚀后的Si掺杂GaN外延层中的位错腐蚀坑.根据腐蚀坑的不同形状和在表面的特定位置可将其分成三种类型,它们的起源可由一个关于腐蚀机制的模型加以解释.纯螺位错易于沿着由它结束的表面阶梯被腐蚀,形成一个小的Ga极性面以阻止进一步的纵向腐蚀,因而其腐蚀坑是位于两个表面阶梯交结处的截底倒六棱椎.纯刃位错易于沿位错线被腐蚀,因而其腐蚀坑是沿着表面阶梯分布的尖底倒六棱椎.极性在GaN的腐蚀过程中起了重要作用.     

用原子力显微镜和扫描电镜研究GaN外延层中的位错腐蚀坑

用原子力显微镜和扫描电镜相结合的方法表征了KOH腐蚀后的Si掺杂GaN外延层中的位错腐蚀坑.根据腐蚀坑的不同形状和在表面的特定位置可将其分成三种类型,它们的起源可由一个关于腐蚀机制的模型加以解释.纯螺位错易于沿着由它结束的表面阶梯被腐蚀,形成一个小的Ga极性面以阻止进一步的纵向腐蚀,因而其腐蚀坑是位于两个表面阶梯交结处的截底倒六棱椎.纯刃位错易于沿位错线被腐蚀,因而其腐蚀坑是沿着表面阶梯分布的尖底倒六棱椎.极性在GaN的腐蚀过程中起了重要作用.     

Space Surface Parameters Determined from Fourier Transforms in Atomic Force Microscopy

A tabular analytic method for calculating space surface parameters of different materials is suggested. It uses Fourier transforms obtained with an atomic force microscope. Examples of calculation are given for periodic space structures and surfaces with different degrees of anisotropy and periodicity. It is shown that space parameters, namely, texture direction and texture direction index and also radial wavelength and radial wavelength index, allow anisotropy characterization and periodicity determination at a nanometer scale.     

超光滑光学基底表面原子力显微镜测试方法

原子力显微镜(AFM)是评价亚纳米级表面粗糙度σRMS最主要的测试仪器,但其测试结果会因采样条件(采样间距、采样点数)及测量点位置变化而改变。以AFM测试超光滑光学基底随机表面为例,应用累积功率谱理论建立了确定合理采样条件的方法,避免了采样条件选取不当带来的数据丢失或冗余;通过全局优化选取测量点和局部优化选取测量点相结合,降低了样品表面区域性差异给测试结果带来的不确定性,并大大减少了获得可靠测试结果所需的测试量。上述工作为超光滑光学基底AFM测试提供了有效方案。     

人外周血淋巴细胞体外刺激活化的原子力显微镜研究

本文利用原子力显微镜,对分离的人外周血淋巴细胞和经多克隆刺激剂佛波醇酯(PDB)和离子霉素(Ion)刺激活化的淋巴细胞形态和膜表面超微结构的形态学变化进行了研究。结果表明:淋巴细胞在受刺激后形貌发生明显变化,尺寸变大,同时细胞表面超微结构也趋复杂,出现免疫突触。这些形态变化是与淋巴细胞的功能相适应的,AFM是研究淋巴细胞形态学变化和细胞结构功能之间关系的有力工具。