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Unveiling localized electronic properties of ReS2 thin layers at nanoscale using Kelvin force probe microscopy combined with tip-enhanced Raman spectroscopy
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作者 罗宇 苏伟涛 +4 位作者 张娟娟 陈飞 武可 曾宜杰 卢红伟 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期598-603,共6页
Electronic properties of two-dimensional(2D) materials can be strongly modulated by localized strain. The typical spatial resolution of conventional Kelvin probe force microscopy(KPFM) is usually limited in a few hund... Electronic properties of two-dimensional(2D) materials can be strongly modulated by localized strain. The typical spatial resolution of conventional Kelvin probe force microscopy(KPFM) is usually limited in a few hundreds of nanometers, and it is difficult to characterize localized electronic properties of 2D materials at nanoscales. Herein, tip-enhanced Raman spectroscopy(TERS) is proposed to combine with KPFM to break this restriction. TERS scan is conducted on ReS2bubbles deposited on a rough Au thin film to obtain strain distribution by using the Raman peak shift. The localized contact potential difference(CPD) is inversely calculated with a higher spatial resolution by using strain measured by TERS and CPD-strain working curve obtained using conventional KPFM and atomic force microscopy. This method enhances the spatial resolution of CPD measurements and can be potentially used to characterize localized electronic properties of 2D materials. 展开更多
关键词 few layer ReS2 tip enhanced Raman spectroscopy local strain Kelvin probe force microscopy
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Geometric phase helical PSF for simultaneous orientation and 3D localization microscopy
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作者 周勇壮 张洪硕 +2 位作者 沈咏 Andrew R.Harvey 邹宏新 《Chinese Optics Letters》 SCIE EI CAS CSCD 2024年第3期25-30,共6页
The 3D location and dipole orientation of light emitters provide essential information in many biological,chemical,and physical systems.Simultaneous acquisition of both information types typically requires pupil engin... The 3D location and dipole orientation of light emitters provide essential information in many biological,chemical,and physical systems.Simultaneous acquisition of both information types typically requires pupil engineering for 3D localization and dual-channel polarization splitting for orientation deduction.Here we report a geometric phase helical point spread function for simultaneously estimating the 3D position and dipole orientation of point emitters.It has a compact and simpler optical configuration compared to polarization-splitting techniques and yields achromatic phase modulation in contrast to pupil engineering based on dynamic phase,showing great potential for single-molecule orientation and localization microscopy. 展开更多
关键词 PSF engineering geometric phase single-molecule orientation and localization microscopy
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Construction of a fusion protein expression vector MK-EGFP and its subcellular localization in different carcinoma cell lines 被引量:6
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作者 Li-Cheng Dai Di-Yong Xu +5 位作者 Xing Yao Li-Shan Min Ning Zhao Bo-Ying Xu Zheng-Ping Xu Yong-Liang Lu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第47期7649-7653,共5页
AIM: To construct an expression plasmid encoding human wild-type midkine (MK) and enhanced green fluorescence protein (EGFP) fusion protein (MK-EGFP), and to analyze the subcellular localization of MK in differ... AIM: To construct an expression plasmid encoding human wild-type midkine (MK) and enhanced green fluorescence protein (EGFP) fusion protein (MK-EGFP), and to analyze the subcellular localization of MK in different cardnoma cell lines. METHODS: Two kinds of MK coding sequences with or without signal peptide were cloned into plasmid pEGFP-N2, and the recombinant plasmids constructed were introduced into HepG2, MCF7 and DU145 cells, respectively, by transfection. With the help of laser scanning confocal microscopy, the expression and subcellular localization of MK-GFP fusion protein could be detected. RESULTS: Compared with the GFP control, in which fluorescence was detected diffusely over the entire cell body except in the nucleolus, both kinds of fusion protein MK-GFP were localized exclusively to the nucleus and accumulated in the nucleolus in the three kinds of cancer cell lines. CONCLUSION: This study reveals the specific nucleolar translocation independent of signal peptide, which may be involved in the mechanism that MK works. It provides valuable evidence for further study on the functions of MK in nucleus and its possible mechanisms, in which ribosomal RNA transcription and ribosome assembly are involved. 展开更多
关键词 MIDKINE Subcellular localization Laser scanning confocal microscopy
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Quantitative measurement of local elasticity of SiO_x film by atomic force acoustic microscopy 被引量:2
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作者 何存富 张改梅 吴斌 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第8期449-455,共7页
In this paper the elastic properties of SiOx film are investigated quantitatively for local fixed point and qualitatively for overall area by atomic force acoustic microscopy (AFAM) in which the sample is vibrated a... In this paper the elastic properties of SiOx film are investigated quantitatively for local fixed point and qualitatively for overall area by atomic force acoustic microscopy (AFAM) in which the sample is vibrated at the ultrasonic frequency while the sample surface is touched and scanned with the tip contacting the sample respectively for fixed point and continuous measurements. The SiOx films on the silicon wafers are prepared by the plasma enhanced chemical vapour deposition (PECVD), The local contact stiffness of the tip-SiOx film is calculated from the contact resonance spectrum measured with the atomic force acoustic microscopy. Using the reference approach, indentation modulus of SiOx film for fixed point is obtained. The images of cantilever amplitude are also visualized and analysed when the SiOx surface is excited at a fixed frequency. The results show that the acoustic amplitude images can reflect the elastic properties of the sample. 展开更多
关键词 atomic force acoustic microscopy SiOx film contact resonance frequency local elasticity
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Localization of RanBP1 in Early Embryonic Development of Mice
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作者 Hu Xiao-yang Zeng Xiao +4 位作者 Xu Ying Ding Cong Zhang Dan-dan Jia Zhen-zhen Cao Yun-kao 《Journal of Northeast Agricultural University(English Edition)》 CAS 2020年第2期116-121,共6页
RanBP1 is a binding protein of Ran that plays a pivotal role in nucleocytoplasmic transport.In this study,the localization and possible functions of RanBP1 were examined,during the early embryonic development of mice.... RanBP1 is a binding protein of Ran that plays a pivotal role in nucleocytoplasmic transport.In this study,the localization and possible functions of RanBP1 were examined,during the early embryonic development of mice.Immunofluorescence results showed that RanBP1 was mainly localized in cytoplasm at mitosis interphase,and its concentration was lower in nucleus and the lowest in nucleolus.With the formation of the spindle in the early embryonic cells,RanBP1 condensed area took the shape of spindle microtubule,the concentration of RanBP1 was low in the site of chromosome.During the formation of nucleus,RanBP1 concentrated in nucleus and there were few dots of RanBP1 around the nucleolus.These dots were lost after the nucleus full growth.The results showed that RanBP1 had important roles in nucleocytoplasmic transport,spindle formation and nuclear assembly in the early embryonic development of mice. 展开更多
关键词 RanBP1 confocal microscopy localization MOUSE early embryonic development
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Application of Fuzzy Logic Algorithm to Single-Molecule Force Spectroscopy of the Streptavidin-Biotin System
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作者 Hiroyuki Tahara Takashi Nyu +2 位作者 Evan Angelo Quimada Mondarte Tatsuhiro Maekawa Tomohiro Hayashi 《Advances in Materials Physics and Chemistry》 2018年第5期217-226,共10页
The rupture force of the streptavidin-biotin complex was investigated using atomic force microscopy (AFM). The most frequently observed rupture force (MFOF), which is essential for the evaluation of the potential land... The rupture force of the streptavidin-biotin complex was investigated using atomic force microscopy (AFM). The most frequently observed rupture force (MFOF), which is essential for the evaluation of the potential landscape, was evaluated by processing 22,500 force curves using two methods. One method is a conventional method, which is usually built in commercial AFM systems, i.e., difference between the baseline value and the minimum force value in the force curve. The other is a detection of rupture events based on a fuzzy logic algorithm to detect the rupture event from analyzing the shape of the force curves. Our statistical analysis revealed that the conventional method exhibited a significant artifact, which is the increase in the population of small forces comparable to thermal noise of cantilevers, resulting in a smaller MFOF. Based on this finding, we discuss the choice of a method and its effecton the illustrated potential landscapes of ligand-receptor complexes. 展开更多
关键词 single-molecule FORCE Spectroscopy ATOMIC FORCE microscopy Fuzzy Logic ALGORITHM STREPTAVIDIN BIOTIN
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Classification of Human Protein in Multiple Cells Microscopy Images Using CNN
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作者 Lina Al-joudi Muhammad Arif 《Computers, Materials & Continua》 SCIE EI 2023年第8期1763-1780,共18页
The subcellular localization of human proteins is vital for understanding the structure of human cells.Proteins play a significant role within human cells,as many different groups of proteins are located in a specific... The subcellular localization of human proteins is vital for understanding the structure of human cells.Proteins play a significant role within human cells,as many different groups of proteins are located in a specific location to perform a particular function.Understanding these functions will help in discoveringmany diseases and developing their treatments.The importance of imaging analysis techniques,specifically in proteomics research,is becoming more prevalent.Despite recent advances in deep learning techniques for analyzing microscopy images,classification models have faced critical challenges in achieving high performance.Most protein subcellular images have a significant class imbalance.We use oversampling and under sampling techniques in this research to overcome this issue.We have used a Convolutional Neural Network(CNN)model called GapNet-PL for the multi-label classification task on the Human Protein Atlas Classification(HPA)Dataset.Authors have found that the ParametricRectified LinearUnit(PreLU)activation function is better than the Scaled Exponential LinearUnit(SeLU)activation function in the GapNet-PL model in most classification metrics.The results showed that the GapNet-PL model with the PReLU activation function achieved an area under the ROC curve(AUC)equal to 0.896,an F1 score of 0.541,and a recall of 0.473. 展开更多
关键词 CNN PROTEIN PReLU SeLU microscopy images subcellular localization multi-cells
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微流体压力驱动的扫描电化学池显微镜长时间稳定成像
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作者 王志武 庄健 +2 位作者 宁少慧 程磊 郑强强 《光学精密工程》 EI CAS CSCD 北大核心 2024年第10期1528-1537,共10页
为了提升扫描电化学池显微镜(SECCM)对复杂形貌表面电化学活性成像能力,以及避免探针尖端微液滴蒸发和结晶,进而实现长时间、稳定成像,构建了基于纳米移液管探针微流体压力驱动的扫描电化学成像系统。对探针尖端开口处的微液滴流量补偿... 为了提升扫描电化学池显微镜(SECCM)对复杂形貌表面电化学活性成像能力,以及避免探针尖端微液滴蒸发和结晶,进而实现长时间、稳定成像,构建了基于纳米移液管探针微流体压力驱动的扫描电化学成像系统。对探针尖端开口处的微液滴流量补偿、复杂表面形貌同步电化学活性成像可靠性等进行了研究。首先,构建了基于移液管探针微流体压力驱动的SECCM扫描成像系统。接着,建立了移液管微流体压力驱动的探针检测数值模型,研究了探针末端背压与探针尖端流体流量间的关系。然后,在理论模型分析的基础上,实验测试了微流体驱动新方法对具有较大表面形貌特征的玻碳电极材料和铝合金材料表面高分辨率形貌和电化学活性同步成像能力。实验结果表明:新方法可对硬质材料表面(样品表面高度起伏为探针开口直径20倍以上)实现长时间、稳定的电化学成像。新系统的研制将为研究人员在材料电化学、金属材料腐蚀研究提供强有力的工具。 展开更多
关键词 扫描电化学池显微镜 局部高分辨率 循环伏安测量 形貌 电化学活性
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纳米级光学超分辨成像技术研究及展望
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作者 潘天颖 谷陆生 纪伟 《生物化学与生物物理进展》 SCIE CAS CSCD 北大核心 2024年第10期2519-2531,共13页
荧光显微成像技术能够将细胞生理活动可视化,是现代生命科学研究的重要手段。超分辨成像技术的出现将研究推进到亚细胞结构层次,而具有纳米级分辨率的单分子定位成像技术成为了研究细胞器、大分子复合物空间分布及相互作用的有力工具。... 荧光显微成像技术能够将细胞生理活动可视化,是现代生命科学研究的重要手段。超分辨成像技术的出现将研究推进到亚细胞结构层次,而具有纳米级分辨率的单分子定位成像技术成为了研究细胞器、大分子复合物空间分布及相互作用的有力工具。继2014年超分辨成像技术获得诺贝尔化学奖后,《自然》(Nature)发布的2024年值得关注的七大技术中再次将纳米级分辨率光学成像技术作为热点进行介绍,超高分辨率成像技术是重要的前沿研究领域。本文首先简要介绍了荧光显微成像技术的发展历史、荧光显微镜的基础概念、超分辨成像技术的基本概况,之后着重介绍了单分子超分辨成像技术的研究进展,并在最后对该技术的发展及应用做了展望。 展开更多
关键词 超分辨成像技术 单分子定位成像技术 多色成像 三维成像 纳米级成像技术
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AlSc15中间合金中Al_(3)Sc金属间化合物的电化学行为及对局部腐蚀的影响
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作者 蒋伟 高坤元 +6 位作者 胡秀华 文胜平 黄晖 吴晓蓝 魏午 聂祚仁 启世亮 《轻合金加工技术》 CAS 2024年第2期54-58,共5页
将过共晶AlSc15合金加热至液态,以10℃/h速率冷却得到毫米级尺寸的Al_(3)Sc金属间化合物。利用微区电化学和扫描开尔文探针力显微镜(SKPFM)研究了Al_(3)Sc金属间化合物在不同pH值的0.1 mol/L NaCl溶液中的电化学特征及对局部腐蚀敏感性... 将过共晶AlSc15合金加热至液态,以10℃/h速率冷却得到毫米级尺寸的Al_(3)Sc金属间化合物。利用微区电化学和扫描开尔文探针力显微镜(SKPFM)研究了Al_(3)Sc金属间化合物在不同pH值的0.1 mol/L NaCl溶液中的电化学特征及对局部腐蚀敏感性的影响。结果表明,Al_(3)Sc金属间化合物存在自钝化现象,且在碱性环境中有明显的维钝区域;随着pH值的增加,Al_(3)Sc腐蚀电位逐渐降低,在中性和碱性条件下的腐蚀速率明显低于酸性条件下的;Al_(3)Sc金属间化合物与周围铝基体之间的伏打电位差约为40 mV,在铝合金中可能作为较弱的局部阴极,对电偶腐蚀的影响不大。 展开更多
关键词 Al_(3)Sc金属间化合物 微电化学技术 扫描开尔文 局部腐蚀
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A review on the synergism between corrosion and fatigue of magnesium alloys:Mechanisms and processes on the micro-scale
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作者 Mara Cristina Lopes de Oliveira Rejane Maria Pereira da Silva +1 位作者 Ricardo M.Souto Renato Altobelli Antunes 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第8期3062-3093,共32页
Understanding the interaction between cyclic stresses and corrosion of magnesium(Mg)and its alloys is increasingly in demand due to the continuous expansion of structural applications of these materials.This review is... Understanding the interaction between cyclic stresses and corrosion of magnesium(Mg)and its alloys is increasingly in demand due to the continuous expansion of structural applications of these materials.This review is dedicated to exploring the corrosion-fatigue mechanisms of these materials,with an emphasis on microscale processes,and the possibility of expanding current knowledge on this topic using scanning electrochemical techniques.The interaction between fatigue and corrosion of Mg alloys is analyzed by considering the microstructural aspects(grain size,precipitates,deformation twins),as well as the formation of pits.Furthermore,in the case of coated alloys,the role of coating defects in these phenomena is also described.In this context,the feasibility of using scanning electrochemical microscopy(SECM),scanning vibrating electrode technique(SVET),scanning ion-selective electrode technique(SIET),localized electrochemical impedance spectroscopy(LEIS)and scanning Kelvin probe(SKP)methods to study the corrosion-fatigue interaction of Mg alloys is examined.A comprehensive review of the current literature in this field is presented,and the opportunities and limitations of consolidating the use of these techniques to study the microscale processes involved in Mg corrosion-fatigue are discussed. 展开更多
关键词 Magnesium alloys localized corrosion and protection FATIGUE Scanning electrochemical microscopy Scanning vibrating electrode technique Scanning ion-selective electrode technique Scanning Kelvin probe Chemical imaging
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超声定位显微成像对肿瘤演进及磁热疗效的评估
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作者 冯宇康 王罗军 +7 位作者 郑罕 孔新丽 杨思琦 陈海鑫 陈冕 陈昕 陈思平 林浩铭 《声学学报》 EI CAS CSCD 北大核心 2024年第3期417-423,共7页
肿瘤的演进和消融伴随着微血管网络的变化,因此使用超声定位显微成像技术评估肿瘤区域微血管及其在磁热疗作用下的变化。通过构建小鼠肿瘤动物模型,搭建实验平台进行超声动物实验,实现肿瘤内部细微血管成像。通过向肿瘤部位注射磁纳米粒... 肿瘤的演进和消融伴随着微血管网络的变化,因此使用超声定位显微成像技术评估肿瘤区域微血管及其在磁热疗作用下的变化。通过构建小鼠肿瘤动物模型,搭建实验平台进行超声动物实验,实现肿瘤内部细微血管成像。通过向肿瘤部位注射磁纳米粒子,在外部磁场的作用下产生热效应,实现对肿瘤的磁热治疗。实验结果表明,超声定位显微镜成像能观察到肿瘤生长演进过程中微血管网络的变化,且其变化情况与免疫组化结果具有一致性。此外,磁热治疗后肿瘤内部血管明显减少,与病理切片结果相符,验证了磁热治疗的可行性。 展开更多
关键词 超声定位显微成像 微血管图像 肿瘤演进 磁热治疗
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Local leakage current behaviours of BiFeO_3 films 被引量:1
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作者 邹成 陈斌 +5 位作者 朱小健 左正笏 刘宜伟 陈远富 詹清峰 李润伟 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第11期493-498,共6页
The leakage current behaviours of polycrystalline BiFeO3 thin films are investigated by using both conductive atomic force microscopy and current-voltage characteristic measurements. The local charge transport pathway... The leakage current behaviours of polycrystalline BiFeO3 thin films are investigated by using both conductive atomic force microscopy and current-voltage characteristic measurements. The local charge transport pathways are found to be located mainly at the grain boundaries of the films. The leakage current density can be tuned by changing the post-annealing temperature, the annealing time, the bias voltage and the light illumination, which can be used to improve the performances of the ferroelectric devices based on the BiFeOa films. A possible leakage mechanism is proposed to interpret the charge transports in the polycrystalline BiFeO3 films. 展开更多
关键词 polycrystalline BiFeO3 thin films local leakage current conductive atomic force microscopy
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Localized CO_2 laser bonding process for MEMS packaging 被引量:4
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作者 SUN Li A. P. MALSHE +1 位作者 S. CUNNINGHAM A. MORRIS 《中国有色金属学会会刊:英文版》 CSCD 2006年第B02期577-581,共5页
The packaging poses a critical challenge for commercialization of MEMS products. Major problems with the packaging process include degraded reliability caused by the excess stress due to thermal mismatch and altered p... The packaging poses a critical challenge for commercialization of MEMS products. Major problems with the packaging process include degraded reliability caused by the excess stress due to thermal mismatch and altered performance of the MEMS device after packaging caused by thermal exposure. The localized laser bonding technique for ceramic MEMS packaging to address above-mentioned challenges was investigated. A continuous wave CO2 laser was used to locally heat sealing material for ceramic MEMS package lid to substrate bonding. To determine the laser power density and scanning speed, finite element analysis thermal models were constructed to simulate the localized laser bonding process. Further, the effect of external pressure at sealing ring on the bonding formation was studied. Pull testing results show that the scanning speed and external pressure have significant influence on the pull strength at the bonding interface. Cross-sectional microscopy of the bonding interface indicates that the packages bonded with relatively low scanning speed and external pressure conditions have higher bonding quality. This research demonstrates the potential of localized laser bonding process for ceramic MEMS packaging. 展开更多
关键词 微电子机械系统 MEMS 封装 局部激光焊接过程 有限元分析
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STM investigations of local potential barrier distribution of the atomic surface of graphite 被引量:1
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作者 CAO Jian zhang 1, SONG Jian ping 2, XU Jia dong 1, CHEN Guo rui 1(1.Department of Electronic Engineering, Northwestern Polytechnical University, Xian, P.R.China,710072 2. Department of Electronic Engineering, Xian Jiaotong University, Xian 《原子与分子物理学报》 CAS CSCD 北大核心 2000年第4期603-607,共5页
To modulate the tunneling gap with the lock in amplifier in the scanning tunneling microscopy(STM), information of the tunneling current variation can be obtained. The local potential barrier distribution of graphite ... To modulate the tunneling gap with the lock in amplifier in the scanning tunneling microscopy(STM), information of the tunneling current variation can be obtained. The local potential barrier distribution of graphite surface atoms is got by means of such technology. Compared with STM image under topography observation mode, the local potential barrier image has higher resolution and less influence on the tip and better anti interference capability. Observed results of the graphite are given and discussed in this paper. 展开更多
关键词 STM 局部势垒分布 石墨原子表面
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超高真空原子尺度Au_(x)/Si(111)-(7×7)表面吸附的电荷分布测量
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作者 冯婕 郭强 +6 位作者 舒鹏丽 温阳 温焕飞 马宗敏 李艳君 刘俊 伊戈尔·弗拉基米罗维奇·雅明斯基 《物理学报》 SCIE EI CAS CSCD 北大核心 2023年第11期165-175,共11页
原子尺度表面吸附Au原子的物理化学性质对研究纳米器件的制备以及表面催化等起着非常重要的作用.利用调频开尔文探针力显微镜研究了室温下Au在Si(111)-(7×7)表面吸附的电荷分布的特性.首先,利用自制超高真空开尔文探针力显微镜成... 原子尺度表面吸附Au原子的物理化学性质对研究纳米器件的制备以及表面催化等起着非常重要的作用.利用调频开尔文探针力显微镜研究了室温下Au在Si(111)-(7×7)表面吸附的电荷分布的特性.首先,利用自制超高真空开尔文探针力显微镜成功得到了原子尺度Au在Si(111)-(7×7)不同吸附位的表面形貌与局域接触电势差(LCPD);其次,通过原子间力谱与电势差分析了Au/Si(111)-(7×7)特定原子位置的原子特性,实现了原子识别;并通过结合差分电荷密度计算解释了Au/Si(111)-(7×7)表面间电荷转移与Au的吸附特性.结果显示,Au原子吸附有单原子和团簇形式.其中,Au团簇以6个原子为一组呈六边形结构吸附于Si(111)-(7×7)的层错半单胞内的3个中心原子位;单个Au原子吸附于非层错半单胞的中心顶戴原子位;同时通过电势差测量得知单个Au原子和Au团簇失去电子呈正电特性.表面差分电荷密度结果显示金在吸附过程中发生电荷转移,失去部分电荷,使得吸附原子位置上的功函数局部减少.在短程力、局域接触势能差和差分电荷密度发生变化的距离范围内,获得了理论和实验之间的合理一致性. 展开更多
关键词 开尔文探针力显微镜 Si(111)-(7×7) 局域接触势能差 表面电荷
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