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《材料保护》2016,(5)
传统电化学检测技术难以深入研究腐蚀的萌生、发展、转移、抑制等过程,而基于扫描探针的电化学检测技术弥补了这一不足。从工作原理和应用现状,简要概述了4种适用于金属/有机涂层体系腐蚀研究的基于扫描探针、具有高空间分辨率的电化学检测技术,分别为扫描电化学显微镜(SECM)、扫描振动电极技术(SVET)、局部电化学阻抗谱(LEIS)、扫描开尔文探针技术(SKP)。4种电化学检测技术均利用金属/有机涂层体系电化学的不均一性,通过检测电流、电压或者阻抗等信号,从微观上反映该体系腐蚀的全过程。基于扫描探针的电化学检测技术的发展及应用,能够从微观上解释金属/有机涂层体系腐蚀发生、发展过程及机理。 相似文献
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扫描隧道显微镜和原子力显微镜的发明大大促进了扫描探针显微镜的发展。本文介绍扫描隧道显微镜和原子力显微镜的基本工作原理、发展背景以及以扫描隧道显微镜和原子力显微镜为基础衍生出来的各种扫描探针显微镜的应用。扫描探针显微镜是一种新的探测仪器,它在三维方向上的分辨率均可以达到原子量级的水平,因此在微电子学、微机械学、计量学、化学和生物医学等领域中有广泛的应用前景。 相似文献
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主要介绍了扫描隧道显微镜在材料的相变过程、材料表面腐蚀过程、纳米材料的组织结构等表面分析中的应用,并具体列举了扫描隧道显微镜在高分子材料聚集态结构分析中的几个实际应用例子。 相似文献
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扫描探针显微镜在粗糙度、纳米尺寸、表面形貌观测方面的应用 总被引:4,自引:0,他引:4
扫描探针显微镜是近十几年来在表面特征、表面形貌观测方面最重大的进展之一,是纳米测量学的基本工具。叙述了扫描探针显微镜的工作原理、检测模式及在观察检测纳米级的粗糙度、微小尺寸、表面形貌方面的特点和方法,比较了原子力显微镜、常规的表面轮廓仪、干涉显微镜、扫描电子显微镜在表面特性、表面形貌观测方面的性能,着重介绍了扫描探针显微镜在粗糙度、纳米尺寸、表面形貌观测方面的应用和存在的问题。 相似文献
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原子力显微镜(AFM)有接触和轻敲两种工作方式,可以在气相和液相下工作.在液相工作状态下,浸没于水中的探针和样品表面会形成一层水化膜.在探针和样品表面形成的水化膜是否会对扫描图像产生影响以及产生何种影响是一个值得研究的问题.本文用原子力显微镜对1μm标准校正光栅在空气和水两种媒质中进行了图像扫描,扫描分别采用接触和轻敲两种工作方式.扫描图像显示,在液相工作环境中,水化膜在探针和样品表面的形成将严重影响轻敲工作方式所形成的图像,而接触方式的扫描图像基本不受影响. 相似文献
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Barth C Foster AS Henry CR Shluger AL 《Advanced materials (Deerfield Beach, Fla.)》2011,23(4):477-501
The current status and future prospects of non-contact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM) for studying insulating surfaces and thin insulating films in high resolution are discussed. The rapid development of these techniques and their use in combination with other scanning probe microscopy methods over the last few years has made them increasingly relevant for studying, controlling, and functionalizing the surfaces of many key materials. After introducing the instruments and the basic terminology associated with them, state-of-the-art experimental and theoretical studies of insulating surfaces and thin films are discussed, with specific focus on defects, atomic and molecular adsorbates, doping, and metallic nanoclusters. The latest achievements in atomic site-specific force spectroscopy and the identification of defects by crystal doping, work function, and surface charge imaging are reviewed and recent progress being made in high-resolution imaging in air and liquids is detailed. Finally, some of the key challenges for the future development of the considered fields are identified. 相似文献
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We have studied grain-shape dependence of Kelvin probe force microscopy of SrBi2Ta2O9 thin films on epitaxial La0.5Sr0.5CoO3/LaAlO3 substrates. By changing the growth condition in pulsed laser deposition, we have grown the SrBi2Ta2O9 thin films with various grain shapes. The shape and the orientation of SrBi2Ta2O9 the thin films with various growth conditions have been analyzed by X-ray diffraction and scanning electron microscope. The large number of the long rectangular grains was observed accompanied with relatively larger (220) peaks than other peaks. From the Kelvin probe force microscope study, it has been observed that the long rectangular grains showed characteristics of easy ferroelectric domain switching at a low writing bias and weaker influence of surface charges. 相似文献
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I. A. Eliseyev A. N. Smirnov S. P. Lebedev V. N. Panteleev P. A. Dementev J. Pezoldt 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(4):316-320
AbstractThe buffer layer samples grown on the Si-face of the 4H- and 6H-SiC substrates were heated in a hydrogen flow at different temperatures (600–900?°C) and heating times (40–60?min) in order to obtain quasi-freestanding monolayer graphene. Their structural properties were characterized before and after heating by using the methods of Raman spectroscopy, atomic force microscopy, Kelvin probe force microscopy, and low-energy electron diffraction. The dependence of the degree of coverage of the sample with quasi-freestanding graphene and the number of defects in the resulting films on the heating temperature was studied. As a result of optimization of the technological parameters, it is shown that the highest quality of the resulting quasi-freestanding graphene can be achieved by using the following parameters: heating time of 40?minutes and temperature of 800?°C. 相似文献
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Palermo V Liscio A Gentilini D Nolde F Müllen K Samorì P 《Small (Weinheim an der Bergstrasse, Germany)》2007,3(1):161-167
A scanning probe microscopy investigation of the self-organization and local electronic properties of spin-coated ultrathin films of N-alkyl substituted perylenetetracarboxdiimide (PDI) is described. By carefully balancing the interplay between molecule-molecule and molecule-substrate interactions, PDI is able to form highly ordered supramolecular architectures on flat surfaces from solution. On an electrically insulating yet highly polar surface (mica) PDI forms strongly anisotropic architectures with needlelike structures with lengths of up to a few micrometers. On a conductive yet apolar surface (highly oriented pyrolytic graphite), the competition between the strong molecule-substrate interactions and the intermolecular forces leads to the generation of more disordered structures. The local electronic properties of these architectures are studied by Kelvin probe force microscopy by estimating their surface potential (SP). Quantitative measurements of the SP are obtained by analyzing the experimentally estimated SP data with a computational model, which discriminates between the intrinsic SP and the effect of long-range tip-surface interactions. The SP of PDI aggregates depends on the structural order at the supramolecular level. Narrow needles of constant width reveal identical SPs independent of length. Wider needles with a polydisperse width distribution exhibit a greater SP. 相似文献
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Using the scanning probe technique known as Kelvin probe force microscopy it is possible to successfully devise a sensor for charged biomolecules. The Kelvin probe force microscope is a tool for measuring local variations in surface potential across a substrate of interest. Because many biological molecules have a native state that includes the presence of charge centres (such as the negatively charged backbone of DNA), the formation of highly specific complexes between biomolecules will often be accompanied by local changes in charge density. By spatially resolving this variation in surface potential it is possible to measure the presence of a specific bound target biomolecule on a surface without the aid of special chemistries or any form of labelling. The Kelvin probe force microscope presented here is based on an atomic force microscopy nanoprobe offering high resolution (<10 nm), sensitivity (<50 nM) and speed (>1,100 microm s(-1)), and the ability to resolve as few as three nucleotide mismatches. 相似文献
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Thin blend polymer films made of poly(3-hexylthiophene-2,5-diyl) (electron donor) and fullerene derivatives as electron acceptors ([6,6]-thienylC61 butyric acid methyl ester and [6,6]-thienylC71 butyric acid methyl ester) are prepared by the spin-coating technique on indium tin oxide covered glass substrates. Time-resolved photo-induced changes of surface potentials are detected by Kelvin force microscopy (KFM). Changes of surface potentials by 10-150 mV reveal different quality and kinetics of charge generation in the two blends in short (minutes) and long (hours) time periods. This is attributed to a combination of electron accumulation, trapping, and organic material degradation under ambient conditions. As KFM characterizes the blend films directly without metal contact layer, it reveals differences in the opto-electronic behavior of the blends, which are not detected by common photovoltaic cell characterization. 相似文献
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We demonstrate frequency modulation Kelvin probe force microscopy operated in lift-mode under ambient conditions. Frequency modulation detection is sensitive to force gradients rather than forces as in the commonly used amplitude modulation technique. As a result there is less influence from electric fields originating from the tip's cone and cantilever, and the recorded surface potential does not suffer from the large lateral averaging observed in amplitude modulated Kelvin probe force microscopy. The frequency modulation technique further shows a reduced dependence on the lift-height and the frequency shift can be used to map the second order derivative of the tip-sample capacitance which gives high resolution material contrast of dielectric sample properties. The sequential nature of the lift-mode technique overcomes various problems of single-scan techniques, where crosstalk between the Kelvin probe and topography feedbacks often impair the correct interpretation of the recorded data in terms of quantitative electric surface potentials. 相似文献
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The potential of laser surface melting (LSM) as a pre-treatment prior to conventional anodising has been evaluated on an AA2050-T8 (Al-Cu-Li) aerospace alloy. A KrF excimer laser was utilized, of wavelength of 248 nm, with variation of the number of pulses received per unit area. After LSM, the specimens were anodised at a constant voltage of 12 V in 0.46 M sulphuric acid for 240 s. Material characterization, in terms of surface morphology, microstructure and phase transformation, was performed using scanning and transmission electron microscopies, interferometry and scanning Kelvin probe force microscopy (SKPFM). The corrosion behaviour was evaluated based on the standard ASTM G34-01 EXCO test, revealing the distinct improvement in performance of the combined laser and anodising treatments. 相似文献
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Shiyun Lou Changhua ZhouHuaibin Shen Gang ChengZuliang Du Shaomin ZhouLin Song Li 《Materials Chemistry and Physics》2011
The photoresponse properties of the as-prepared and annealed close-packed CdSe nanocrystal (NC) films were investigated under laser illumination by Kelvin probe force microscopy. The annealing process improved the photoresponse speed of the CdSe NC films. The work function of the annealed CdSe NC films changed more rapidly than that of the non-annealed film in air at room temperature. Combined with X-ray photoelectron spectroscopy measurements and thermogravimetric analysis, the observed phenomena can be interpreted that annealing process removed the organic capping agents completely and eliminated oxide on the CdSe surface, which formed the tunnel barrier between NCs in the CdSe NC films. Consequently, it improved the separation rate of photoelectric charges and thus provided high speed photoresponse. 相似文献
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Sascha Sadewasser 《Thin solid films》2007,515(15):6136-6141
The role of grain boundaries in polycrystalline Cu-III-VI2 absorber material for thin film photovoltaics has not been fully understood and is currently under discussion. Recently, intensive efforts have been devoted to the characterization of the properties of individual grain boundaries using microscopic techniques, including Kelvin probe force microscopy (KPFM). KPFM provides local electronic information by measuring the surface potential in addition to the topography. We introduce the KPFM method and present simulations assessing the technique's limitations with respect to spatial resolution regarding the measurement of grain boundary properties. KPFM studies of individual GBs in the Cu(In,Ga)Se2 materials system are reviewed and critically discussed, considering also results from other microscopic characterization techniques. 相似文献