基于隧道效应的纳米级振动检测及补偿

微振动是提高纳米测量精度的主要障碍,为了减小微振动在STM测量中的影响,需要对微振动进行隔离和检测．因此,抗振、隔振及振动补偿技术成为了纳米测量领域的一大分支．设计了基于隧道效应的纳米级振动传感器,该传感器具有很高的灵敏度和分辨力,并用设计的振动传感器进行了纳米级振动检测试验．在隧道状态下．观察隧道间隙对外界微振动的响应情况,并用测量结果实时对STM测量进行补偿．结果表明,基于隧道效应的测振传感器具有很好的响应特性和良好的幅频特性,并且可以进行STM的振动补偿．     

纳米计量与传递标准

纳米计量不仅提供测量和表征纳米材料及器件基础,同时在纳米生产工艺控制和质量管理领域也扮演重要角色。纳米技术就某种意殳上讲就是实现原子或分子操作的超精细加工技术。纳米科技的各个领域都涉厦对纳米尺度物质的形态、成分、结构及其物理／化学性能(功能)的测量、表征。纳米测量在纳米科技中起着信息采集和分析的不可替代的重要作用。纳米测量技术包括：纳米级精度的尺寸和位移的测量,纳米级表面形貌的测量以及纳米级物理与化学特性测量。目前迫切需要解决的问题有微电子、超精密加工中线竞、台阶、膜厚等测量问题、纳米材料中的粒子特征测量问题和作为纳米科技主要测量和操作工具的扫描探针显微镜(SPM)、扫描电子显微镜(SEM)等的特性表征和测量准确度评定,文章重点评述了国际上为建立可溯源于国际基本单位制(SI)的纳米计量体系努力。包括：纳米尺度测量(台阶、节距)的国际比对,传递标准在纳米计量体系中的特殊作用,用于校准扫描探针显徽镜(SPM)、扫描电子显微镜(SEM)等的传递标准研制概况。     

扫描隧道显微镜对纳米碳酸钙的研究

由于扫描隧道显微镜(STM)具有原子级分辨率,因而是迄今为止观察微米和更小尺度上表面三维形貌极其有效的工具.利用STM可以直接观察纳米碳酸钙的表面形貌、粒径大小、晶形、分散性以及纳米碳酸钙的隧道谱.分析了纳米碳酸钙的量子效应和宏观量子隧道效应.     

纳米级正弦振动幅相特性测量技术的研究

概述外差激光干涉测量技术的基本原理和特点，针对马赫-泽德外差式激光干涉仪在绝对法振动校准技术中的应用，介绍测量系统的构架以及完成数据采集和信号处理的虚拟仪器技术。详细介绍了测量系统频移变换部分和数字信号处理部分的组成原理和技术实现，论述了其中数据采集、数字解调、曲线拟合等技术难点。本文描述的这种振动测量技术运用正弦逼近的信号处理方法，可以对线性正弦振动量进行幅值和相位的纳米级精确测量。     

纳米测量仪器和纳米加工技术

纳米科技是当今国际上的一个热点。文章对纳米科技作了简要介绍, 纳米测量和加工是纳米科技中的一个不可缺少的重要组成部分。叙述了发展纳米测量和纳米加工技术的两个主要途径：一是发展传统技术，主要是电子显微术以及最近发展起来的聚焦离子束（FIB）- 电子束数控加工中心；二是创造新的测量仪器，建立新原理和新方法，介绍了国内外电子显微镜和扫描探针显微镜这两类纳米测量分析仪器的发展、应用和生产现状。指出我国电子显微仪器和扫描探针显微镜的开发和生产面临困境，应尽快建立和加强自己的电子显微仪器和扫描探针显微镜等纳米测量和纳米加工设备制造产业，并列入国家科技发展规划。     

纳米科技浅释

一纳米是一米的十亿分之一。自从扫描隧道显微镜发明后，世界上便诞生了一门以0．1至100纳米这样的尺度为研究对象的前沿学科，这就是纳米科技。[第一段]     

美国研发出测量纳米级材料技术

美国加州大学洛杉矶分校纳米系统科学主任保罗·维斯领导的研究小组开发出了研究纳米级材料相互作用的工具——双扫描隧道显微和微波频率探针．可用于测量单个分子和接触基片表面的相互作用。     

基于SPM的纳米计量中若干重要问题

扫描探针显微镜(SPM)由于具有纳米甚至原子量级的分辨率,20多年来已引起各个领域科学家们的广泛兴趣。在精密工程领域,它作为一种极具前途的纳米计量工具,已在许多国家受到了广泛的重视,如美国NIST,德国PTB和英国NPL等都相继开展了基于SPM的纳米计量技术研究。但作为纳米级的计量分析仪器,不仅要有高分辨率,更要有纳米级甚至更高的精度。     

用于扫描探针电子能谱仪的扫描隧道显微镜

扫描探针电子能谱学是正在发展中的一种结合了扫描隧道显微技术的电子能谱学技术,可以原位地获得固体表面的形貌和能谱信息。本文针对新研制的扫描探针电子能谱仪专门设计制作了一台采用横向隧道结结构、小巧紧凑、稳定对称的扫描隧道显微镜,可以工作在隧道区测量样品表面形貌,也可以在近场发射区测量表面背散射电子能谱。在高定向热解石墨和石墨基底上蒸镀的银膜样品的得到的原子分辨、纳米结构图像和原位电子能量损失谱表明这两种功能已完全实现。     

纳米技术将如何改变生活

纳米陶瓷材料可以大幅度弯曲而不断裂,表现出金属般的柔韧性和可加工性;纳米药物可以进行基因治疗,大大延长人类的寿命……在2004年5月24日于天津开幕的2004国际纳米技术会议上,600多名纳米技术领域的科学家交流、探讨全球范围内纳米技术的最新进展,共同描绘纳米技术将给人类带来的全新生活。据介绍,国际范围内的纳米科研始于上世纪80年代末、90年代初迅速发展。1982年,科学家发明了一种研究纳米的重要工具———扫描隧道显微镜,对纳米科研产生了巨大的促进作用。正如我国著名科学家钱学森曾预言的那样:“纳米左右及纳米以下的结构将是下一…     

Assessment of the resolution of scanning tunneling microscope with a tip of a boron-doped diamond

The assessment of the resolution of scanning tunneling microscope when operated in the scanning mode has been made based on the analysis of the tunneling current on parameters of diamond tip-sample system. The scanning parameters and accuracy of supporting the constant tunneling current by the system of the instrument feedback, at which the presence of the atomic resolution is possible in the case of a single channel of tunneling, have been defined. An alternative (in respect to the best known publications) explanation of the hexagonal structure of the pyrolytic graphite surface observed with atomic resolution has been suggested. The problem of multichannel tunneling caused by the presence of several nanoprotrusions in the diamond probe test zone that initiate tunneling and impair the resolution of a scanning tunneling microscope is discussed.     

Controlled lateral manipulation of molecules on insulating films by STM

On metallic and semiconductor surfaces functional nanostructures can be built with atomic scale precision using the tip of an atomic force microscope/scanning tunneling microscope. In contrast, controlled lateral manipulation on insulators has not been reported. The traditional pushing and pulling based manipulation methods cannot be used for molecules adsorbed on insulating films because of the unfavorable ratio between diffusion barrier and desorption energy. Here, we demonstrate that molecules adsorbed on insulating films can be laterally manipulated in a controlled way by injecting inelastically tunneling electrons at well-defined positions in a molecule. The technique was successfully applied to several different molecules.     

Reversible switching among three adsorbate configurations in a single [2.2]paracyclophane-based molecule

Single 4,7,12,15-tetrakis(4'-dimethylaminostyryl)[2.2]paracyclophane molecules adsorb on NiAl(110) in different configurations. When the symmetry axes of the molecules are properly oriented with respect to the surface lattice, three adsorbate states of different conductance can be reversibly induced and directly imaged with a scanning tunneling microscope. Couplings between tunneling electrons and adsorbate vibrational and electronic states are primarily responsible for the transformation. However, change from low to high conductance configuration can also be triggered by electric field in the junction.     

Electrical Characterization of Ordered Si:P Dopant Arrays

We report on the ability to fabricate arrays of planar, nanoscale, highly doped phosphorus dots in silicon separated by source and drain electrodes using scanning tunneling microscope lithography. We correlate ex situ electrical measurements with scanning tunneling microscope (STM) images of these devices and show that ohmic conduction can be achieved through the disordered array with a P coverage of 0.8times10¹⁴ cm^-2. In comparison, we show that an ordered array of P dots ~6 nm in diameter and containing ~50 P atoms separated by ~4 nm shows nonlinear I-V, characteristic of a series of metallic dots separated by tunnel barriers. These results highlight the use of STM lithography to pattern ordered dopants in silicon down to the sub-10 nm scale     

扫描隧道显微镜轮廓测量数学模型的研究

在量子隧道效应的基础上,建立了适用于增坦表面的扫描隧道显微镜微观轮廓测量的数学模型,并采用傅里叶变换方法对该模型进行了仿真验证。仿真结果表明,该模型较好地反映了扫描隧道显微镜对样品表面轮廓的测量过程。最后,中还对该模型的适用范围进行了讨论。     

The generation of laser difference frequencies using the scanningtunneling microscope

Infrared laser radiation and radio frequency signals were coupled into the tunneling junction of a scanning tunneling microscope (STM), and the difference frequencies and their harmonics generated in the nonlinear junction were studied as a function of the tunneling parameters. Difference frequencies up to 9 GHz were observed. The importance of the results for the difference frequency mixing in metal-insulator-metal (MIM) diodes and for the STM is discussed. The experiments demonstrate that the tunneling junction of the STM can be used to generate difference frequencies of injected electromagnetic radiation in a similar way and with a similar efficiency to those of the MIM diodes. Due to the precise controllability of the tunneling parameters in the STM the frequency mixing process in its tunneling junction is highly reproducible     

Studies of topological features of the HFCVD surface of a nanocrystalline diamond film using a scanning tunneling microscope with a diamond tip

Structural features of HFCVD nanocrystalline diamond films have been considered and a physicomathematical model of the atomic structure of its surface has been constructed. The film has been studied in air using a scanning tunneling microscope with a tip of a boron-doped semiconducting diamond single crystal. Fractal analysis of images of the film surface from scanning tunneling microscope has shown the presence of diamond single crystals of different orientations having a mean size of 31 nm with a fractal dimensionality of 2.36 and 2.73.     

Tuning in to a single molecule: vibrational spectroscopy with atomic resolution

It has recently been shown that the scanning tunneling microscope can be used to obtain the vibrational spectrum of a single molecule on a surface. The ability to obtain both spatial and precise energetic information with angstrom-scale resolution should lead to an enhancement in our ability to understand and engineer surfaces at the atomic level.     

Non-Gaussian fluctuation in the charge transport of Si nanochains

The stability of the tunneling charge transport of a tangle of Si nanochains is investigated at high bias voltages using a micromanipulator in a scanning electron microscope. We confirm that the influence of electron injection due to the electron beam of a scanning electron microscope on the charge transport properties of nanochains is negligible when the electrode gap is small and the bias voltage is large. Under such conditions, current-time curves show large fluctuations. We find that the fluctuation is not a simple Brownian motion, but its distribution function can be fitted well by a Lévy distribution. Its origin is discussed in terms of percolation theory.