基于STM的多模式扫描探针显微镜的建立

在已有的扫描隧道显微镜（STM）基础上设计了一套集STM、 光子扫描隧道显微镜（PSTM）、近场扫描光学显微镜（NSOM）、扫描近场声学显微镜（SNAM）为一体的多模式扫描探针显微系统（SPM）。系统的4种模式可通过转换开关方便地切 换,探头的更换也很容易。利用本系统对典型样品进行了扫描成像。测试表明,系统具有良好的稳定性和超高分辨率。     

扫描探针显微镜在石墨烯研究中的应用

石墨烯是近年来材料、电子和纳米科学中的热门研究课题之一。石墨烯独特的二维结构和原子尺度的平整性使其特别适合利用扫描探针显微镜进行深入研究。利用扫描探针显微镜可以对石墨烯样品的表面的电学、力学和光学等性质进行细致的表征;同时,还可以对石墨烯进行精细的纳米尺度微加工。本文以各种扫描探针显微镜为基础,综述了扫描探针显微镜在石墨烯研究中起到的重要的表征和加工作用。同时,还详细介绍了石墨烯表面研究中的最新进展,并对扫描探针显微镜在石墨烯研究中所具有的潜力进行了探讨。     

基于LCD的扫描显微镜扫描机理

为改进扫描显微镜,提出了一个新的光电扫描方法与装置。此装置采用了一个液晶显示器(LCD),它形成偏相位空间光调制器。该电寻址液晶显示器可形成不同的衍射光学元件。利用相移,可以完全控制扫描束的位置与焦点。当它被放入扫描显微镜中试用后,发现其效果良好,这表明液晶显示器可作为扫描显示镜扫描装置的关键部件。     

压电扫描器非线性校正的实验研究

针对扫描探针显微镜的压电扫描器提出一种非线性校正方法。利用双频激光干涉仪对压电扫描管的位移-电压曲线进行测量,设计非线性校正算法,修正控制电压以实现对压电扫描管非线性校正,将该方法应用于扫描探针显微镜。实验表明该方法能实现压电扫描器的非线性校正。     

扫描探针显微镜[NV2100]

日本奥林巴斯光学工业公司研制NV2100型的扫描探针显微镜,首次实现了与光学显微镜共轴一体化,并于今年四月份开始出售,利用该显微镜可对半导体薄片和光磁盘等最大达8in的大型试验材料表面形     

共焦激光扫描显微镜的研制

利用共焦和扫描原理,研制出共焦激光扫描显微镜样机。     

CHI900扫描电化学显微镜图形处理软件的改进

CHI900扫描电化学显微镜自带的软件不能直接将实验数据或者面扫描图形转换为三维扫描图形,由此提出了基于VC和Matlab混合编程的图形处理软件,实现了三维图形的转换,利用小波阈值对实验曲线降噪,取得了较好的处理效果。     

纳米结构可重入STM/SEM超高真空多功能系统的研制

扫描隧道显微镜（ＳＴＭ）分辨率极高,是微观研究的重要仪器;但由于其视场小,样品易受污染等原因,在某些研究工作听应用受到了限制,扫描电子显微镜（ＳＥＭ）的最低放大倍数在十倍左右,视场可达２０ｍｍ＾２－３０ｍｍ＾２,可以引导扫描隧道显微镜进入试样预期的区域;另外超高真空的扫描电的样品室可以为扫描隧道显微镜提供清洁的工作环境,减少样品的污染。超高真空扫描电与扫描隧道显微镜的结合,可以弥补扫描隧道显微镜的     

非接触式扫描离子电导显微镜技术在探测活体细胞表面微结构中的应用

扫描离子电导显微镜技术是在纳米尺度进行非导电的生物样品成像的一种新型扫描探针显微镜技术。通过成功制备扫描离子电导显微镜扫描探测用纳米尺度玻璃微探针,对其进行了功能性评估;而后通过绘制探针-样品接近曲线,阐述了扫描离子电导显微镜技术实现非接触高分辨率探测的工作原理;最后采用该显微镜技术对导电标准样品及活体肾上皮A6细胞进行了表面形貌扫描成像,并与A6细胞表面形貌的扫描电镜图像进行了对照。结果表明,扫描离子电导显微镜技术不仅可实现导电样品的扫描成像,而且适宜于在生理条件下、非接触式地研究活体细胞表面的三维形貌,从而为人们深入研究细胞表面微观结构与生理功能提供了全新的技术手段。     

扫描探针声显微镜原理及其应用

将声学检测技术与扫描探针显微术相结合,构成的扫描探针声显微镜,不仅可以检测材料表面、亚表面和内部的微小缺陷,还可以分析样品的弹性特性、电特性等物理性能,同时还具有分辨率高的特点,在材料科学和生命科学等领域具有很高的应用价值.目前,得到实际应用的扫描探针声显微镜主要有扫描隧道声显微镜和原子力声显微镜.本文介绍了这两类显微镜的基本工作原理,并对扫描探针声显微镜今后的发展方向进行了探讨.     

原生动物扫描电镜样品制备方法的探讨

以腹毛目纤毛虫棘尾虫、尖毛虫和游仆虫,膜口目纤毛虫草履虫以及腰鞭目鞭毛目角藻为材料,对原生动物扫描电镜样品制备方法作了探讨,提出了样品制备过程中取材固定、脱水、干燥后原生动物在样品台上的定位等值得注意的问题,取得成功的关键及一些体会。     

Macro-scale atomic force microscope: An experimental platform for teaching precision mechatronics

A macro-scale atomic force microscope (macro-AFM) has been designed and used for teaching precision mechatronics. The macro-AFM uses a novel electromagnetic self-sensing self-actuating probe. It operates in frequency-modulation AFM (FM-AFM) mode with intermittent contact. The AFM has an imaging volume of 250 mm × 40 mm × 1 mm with a resolution of about 1 μm at 1 Hz measurement bandwidth. The macro-AFM is simple and relatively inexpensive to build. It is scaled to make motion visible to the eye and is robust for a lab environment, all of which make it an affordable and effective educational tool. The macro-AFM is used in Mechatronics (2.737), a graduate level course at MIT, where in a series of 11 laboratory exercises, the students assembled and programmed the AFM system. This article provides the design and theory used for making and controlling the macro-AFM, as well as experimental results.     

Accurate carrier profiling of n-type GaAs junctions

As CMOS is approaching the 22 nm node, the importance of high-mobility materials such as Ge and GaAs is rapidly increasing. For the timely development of these new technologies accurate dopant and carrier-profiling solutions for source-drain extensions with these materials are required. Identical n-type-doped (Si, Se) layers on same and opposite type medium-doped layers on S.I. GaAs substrates will be investigated, with layer thicknesses ranging from 200 down to 50 nm and doping concentration levels up to 1e20 at/cm³. In this work, secondary ion mass spectrometry will be used for dopant profiling. For GaAs carrier profiling, conventional spreading resistance probe, as commonly used in Si-CMOS, fails. Hence, reliable alternatives need to be found for characterizing these high–low structures. Techniques to be discussed range from the more conventional approaches such as Hall or electrochemical capacitance–voltage (performed by different laboratories), over micro-Raman spectroscopy and photo-luminescence along a beveled surface, up to more advanced approaches using scanning spreading resistance microscopy.     

Atomic scale engineering of nanostructures at silicon carbide surfaces

The atomic scale ordering and properties of cubic silicon carbide surfaces are investigated by room and high-temperature scanning tunneling microscopy. In this review, we will focus on the Si-terminated β-SiC(100) surfaces only. Self-formation of Si atomic lines and dimer vacancy chains on the β-SiC(100) surface is taking place at the phase transition between the 3×2 (Si-rich) and c(4×2) surface reconstructions. Using a rigorous protocol in surface preparation, it is possible to build very long, very straight and defect free Si atomic lines, forming a very large superlattice of massively parallel lines. These self-organized atomic lines are driven by stress. They have unprecedented characteristics with the highest thermal stability ever achieved for nanostructures on a surface (900 °C) and the longest atomic lines ever built on a surface (micrometer scale long). Investigating their dynamics, we learn that their dismantling at high-temperature results from collective and individual mechanisms including one-by-one dimer removal. Overall, this is a model system especially suitable for nanophysics and nanotechnologies.     

Surface properties of AlInGaN/GaN heterostructure

Surface structural, electronic and electrical properties of the quaternary alloy AlInGaN/GaN heterostructures are investigated. Surface termination, atomic arrangement, electronic and electrical properties of the (0001) surface and (10–11) V-defect facets have been experimentally analyzed using various surface sensitive techniques including spectroscopy and microscopy. Moreover, the effect of sub-band gap (of the barrier layer) illumination on contact potential difference (V_CPD) and the role of oxygen chemisorption have been studied.     

Microdroplet and Atomic Force Microscopy Probe Assisted Formation of Acidic Thin Layers for Silicon Nanostructuring

In this work, an aqueous acidic thin‐layer‐based strategy for fabricating nanostructures on silicon by using atomic force microscopy (AFM) nanolithography is presented. The approach involves the formation of microscale droplets via dilute hydrofluoride (DHF) etching, the conversion of the droplets to acidic thin layers by AFM‐probe scanning, and subsequent lithographic operations using a biased probe in the aqueous layers. By varying the concentration of the acidic DHF layers, the thin layers can facilitate the creation of both positive and negative patterns, such as oxide dots and Si pores, through anodic oxidation and dissolution. In particular, the anodic oxidation in the acidic media is associated with the field‐enhanced nonequilibrium dissociation of the weak electrolyte. The Si pore structure formation is related to the field‐assisted dissolution of anodic oxides and the Si substrate. The acidic‐layer‐based technique allows switching between different lithographic modes by changing the acidity of the DHF layers, and is complementary to bulk solution‐based and local meniscus‐based approaches in AFM nanolithography. In principle, this method can also be extended to other materials that have similar reactions with DHF.     

Correlative microscopy analyses of thin-film solar cells at multiple scales

In the present work, a brief overview is given on how to apply transmission (TEM) as well as scanning electron microscopy (SEM) and their related techniques (electron diffraction, energy-dispersive X-ray spectrometry, electron energy-loss spectroscopy, electron holography; electron backscatter diffraction, electron-beam-induced current, cathodoluminescence) for the analysis of interfaces between individual layers or extended structural defects in a thin-film stack. All examples given in the present work were recorded on Cu(In, Ga)Se₂ thin film solar cells, however, the shown experimental approaches may be used on any similar thin-film semiconductor device. A particular aspect is the application of various techniques on the same identical specimen area, in order to enhance the insight into structural, compositional, and electrical properties. For (aberration-corrected) TEM, the spatial resolutions of such measurements can be as low as on the subnanometer scale. However, when dealing with semiconductor devices, it is often necessary to characterize electrical and optoelectronic properties at larger scales, of few 10 nm up to even mm, for which SEM is more appropriate. At the same time, these larger scales provide also enhanced statistics of the analysis. In the present review, it is also outlined how to apply SEM techniques in combination with scanning-probe and optical microscopy, on the same identical positions. Altogether, a multiscale toolbox is provided for the thorough analysis of structure-property relationships in thin-film solar cells using correlative microscopy approaches.     

Proximal probe characterization of nanoscale charge transport properties in Co/SiO2 multilayer structures

We have used scanning force microscopy to study localized charge injection and subsequent charge transport in discontinuous Co/SiO₂ multilayer structures. Charge was injected by applying a bias voltage pulse between a conductive proximal probe tip and the sample. Electrostatic force microscopy was used to image charged areas, to determine quantitatively the amount of stored charge, and to characterize charge transport. Charge was deposited controllably and reproducibly within areas ∼20–50 nm in radius and an exponential decay in the peak charge was observed. The decay times were observed to be dependent on the nominal Co film thickness and on the sign of the deposited charge, with longer decay times for positive charge than for negative charge. These results are interpreted as a consequence of Coulomb-blockade effects, considering charge transport both within the Co layer as well as from the Co layer into the Si substrate.     

一种新型的STM探针

以普通的石英光纤为材料，用熔拉腐蚀复合的方法制备出nm量级的光纤探针，而后在针尖表面镀上数十nm厚的金属膜，达到导电性，使其能传导隧道电流，从而研制出一种新型的扫描隧道显微镜（STM）光纤隧道探针，在STM上取得了比较理想的实验结果。本文将光纤隧道探针与金属隧道探针作了比较，并对其性能作了分析。