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1、纳纳米米材材料料与与功功能能器器件件I In nt tr ro od du uc ct ti io on n t to o N Na an no om ma at te er ri ia al ls s a an nd d F Fu un nc ct ti io on na al l D De ev vi ic ce es s郑郑耿耿锋锋Fall 2018 2What is NANO?纳米材料：基本单元的颗粒或晶粒尺寸至少在一维上小于纳米材料：基本单元的颗粒或晶粒尺寸至少在一维上小于100 nm100 nm，且必须，且必须具有与常规材料截然不同的光、电、热、化学或力学性能的一类材料体系。具有与
2、常规材料截然不同的光、电、热、化学或力学性能的一类材料体系。纳米纳米SnO2镀层镀层纳米碳黑粒子纳米碳黑粒子纳米纳米Au, Ag粒子粒子?3Nano = One billionth of something4Introduction to Nanomaterials & Nanotechnology“There is plenty of room at the bottom” Richard Feynman, 1959Feynman以“由下而上的方法（Bottom-Up）” 出发，提出从单个分子甚至原子开始进行组装，以达到设计要求“至少依我看来，物理学的规律不排除一个原子一个原子地制造物品的可
3、能性。”并预言，“当我们对细微尺寸的物体加以控制的话，将极大得扩充我们获得物性的范围。”51-D, 2-D, and 3-D (0-D) 纳米材料是指在三维空间中至少有一维处于纳米尺度范围纳米材料是指在三维空间中至少有一维处于纳米尺度范围或由它们作为基本单元构成的材料。按维度，纳米材料的或由它们作为基本单元构成的材料。按维度，纳米材料的基本单元可分为三类：零维，一维，二维。因为这些单元基本单元可分为三类：零维，一维，二维。因为这些单元具有量子性质，因此又称为：量子点，量子线和量子阱具有量子性质，因此又称为：量子点，量子线和量子阱 (Quantum dot, Quantum wire, Quan
4、tum well)(Quantum dot, Quantum wire, Quantum well)。6Nanostructure in Nature7Why Study Nanomaterials & NanotechnologyElectronics/CommunicationBiology/MedicineRenewable EnergyWater/FoodBiomimeticsDo Small, Think Big.8第二部分：光学显微镜与电子显微镜第二部分：光学显微镜与电子显微镜 纳米材料结构表征与器件制备（一）：光学显微镜与电子显微镜显微技术原理光学显微镜透射电子显微镜扫描电子显微
5、镜能量损失谱与元素分析9Lens and Imaging System Lenses are the central component of an imaging system. Multiple lens sets are used in a complex microscope to provide high magnification and resolution.10Magnification and Resolution Magnification: the lens capacity to expand an image Resolution: the smallest pixe
6、l can be spatially differentiated from its closest neighbors11Theoretical Resolution Limit for Optical System Theoretical Resolution Limit: is determined by the wavelength of light used for imaging /2 Wavelength of “light”: Optical microscope (visible light): = 400600 nm SEM (110 kV accelerating vol
7、tage): = 1.1 10-11 m (11 pm) TEM (100200 kV accelerating voltage): = 3.6 10-12 m (3.6 pm)12Aberrations Spherical Aberration（球差）（球差）: due to the focus power difference between lens center and edges13Aberrations Chromatic Aberration（色差）（色差）: due to the difference refractive indices for different wavel
8、engths (colors), (recall n = c / )14Aberrations Stigmatism Aberration（像散）（像散）: due to the asymmetry of a lens in the x- and y- directions15Practical Resolution Wavelength of “light”: (recall = h / P) Optical microscope (visible light): = 400600 nm SEM (110 kV accelerating voltage): = 1.1 10-11 m (11
9、 pm) TEM (100200 kV accelerating voltage): = 3.6 10-12 m (3.6 pm) Practical resolution Optical microscope: = 300600 nm SEM (110 kV accelerating voltage): = 210 nm TEM (100200 kV accelerating voltage): = 0.11 nm16Optical (Light) Microscope17Illumination SourceLaser Spectrum18Numerical Aperture（N. A.,
10、 数值孔径）数值孔径） N.A. = n sin The higher N.A. of the objective lens, the better resolution. Methods to improve the N.A. of an objective lens.19Bright Field and Dark Field Imaging Dark field can improve Contrast, not resolution!20Confocal Fluorescence Microscope21Fluorescence Light Path22Transmission Elec
11、tron Microscope1932: first TEM by E. Ruska (Germany)1986: Nobel physics prize组成部分：照明系统、成像系统、记录组成部分：照明系统、成像系统、记录系统、真空系统、电气系统系统、真空系统、电气系统23Working Principle 工作原理工作原理成像原理与光学显微镜类似。它们的根本不同点在于光学显微镜以可见光作照明束，透射电子显微镜则以电子为照明束。在光学显微镜中将可见光聚焦成像的是玻璃透镜，在电子显微镜中相应的为磁透镜。由于电子波长极短，同时与物质作用遵从布拉格（Bragg）方程，产生衍射现象，使得透射电镜自身在
12、具有高的像分辨本领的同时兼有结构分析的功能。 TEM image of an E. coli2425Hot Electron Gun and Field Emission GunHot Electron GunField Emission Gun26Electromagnetic Lens, Apertures Electromagnetic lens The focusing strength can be tuned by adjusting the magnetizing/exciting current（激磁电流）. Over-focus（过焦）and under-focus（欠焦）.
13、 Illumination System High vacuum ( 10-6 Torr) Condenser lens 1 & 2 Obtain highly collimated and uniform electron beam27Electron Diffraction in TEML L RddLRLK L sin 2 sin22sin2 tg 22tg 的乘积为一常数：和值确定，速电压一定时，为衍射相机长度，当加式。这就是电子衍射基本公，得：代入布拉格公式很小，所以子衍射的由于电子波长很短，电K K为相机常数。如果为相机常数。如果K K值已知，即可由衍射斑点的值已知，即可由衍射斑点
14、的R R值计算出晶面组值计算出晶面组d d值：值：RKRLd28Beam Paths in TEM for Imaging and Diffraction TEM Beam Alignment: Beam alignment (from top to down) Abbreviation correction of all lens (the most critical one: objective lens) Adjust sample eucentric height Back focal plane (for the objective aperture) Selected area e
15、lectron diffraction (SAED) aperture29Image and Electron Diffraction Pattern of CrystalsPolycrystalSingle CrystalImageDiffraction3031Example: Direct Kinetics Observation inside TEMObservation of Si nanowire growth by Au nanoparticle catalyzed Vapor-solid-liquid mechanism inside TEM Yang PD, JACS, 200
16、1, 123, 3165.Observation of fullerenes movement and rotation inside a single-wall carbon nanotube by TEM Iijima S., Nano Letters, 2007, 7, 3704.32Scanning Electron Microscope (SEM)Advantages:High magnification (up to 100 kX)High resolution (up to 1 nm)Large field of view3D imaging (although less z-resolution)Simple sample preparationPossible for low vacuum and live organism imaging (Environmental SEM, E-SEM)Energy dispersive spectrum (EDS)Used as nanoscale fabrication tools: e.g. Electron beam l
