现代分析方法与技术
透射电子显微镜
Transmission Electron Microscopy
目录 CONTENTS
1 2 3 4
历史 History 原理 Background 结构 Components
制备 Preparation
应用 Application
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2 透射电子显微镜
历史 HISTORYBiblioteka 2形制 Shapes
field will cause electrons to move according to the left hand rule
热电子发射 或 场电子发射 thermionic or field electron emission
• Hairpin-style filament
5 透射电子显微镜
目录 CONTENTS
1 2 3 4
历史 History 原理 Background 结构 Components
制备 Preparation
应用 Application
5
6 透射电子显微镜
原理 BACKGROUND
电子 ELECTRON
光学显微镜所能达到的最大分辨率受到以下条件的限制
IG Farben-Werke
The De Broglie wavelength of electrons was many orders of magnitude smaller than that for light, theoretically allowing for imaging at atomic scales 1936 改进 TEM 的成像效果，尤其是对生物样品的成像
• Small spike-shaped •使用磁场可以形成 不同聚焦能力的磁透镜
•The use of magnetic fields allows for the
filament
formation of a magnetic lens of variable focusing power
Hairpin style tungsten filament
Developed the field emission gun and added a high quality objective lens to create the modern STEM (Scanning Transmission Electron Microscopy)
A STEM equipped with a 3rd-order spherical aberration corrector
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透射电子显微镜
历史 HISTORY
分辨率的提升 IMPROVING RESOLUTION
Louis Broglie, 1927 Ruska Max de Knoll & Ernst
1932 建造一种新的电子显微镜以直接观察插入显微镜的样品 电子作为物质粒子的波动特性
Louis de Broglie The first practical TEM, originally installed at IG Farben-Werke and (15 1892 – 19 March 1987), Franch Physicist now onAugust display at the Deutsches Museum in Munich, Germany Awarded Nobel Prize in Physics (1929)
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The first international conference in electron microscopy
1950 In Paris 1954 In London 1970 Albert Crewe (Chicago University, USA)
发明了场发射枪，添加了高质量的物镜，发明了现代的扫描透射电子显微镜
Layout of optical components in a basic TEM
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荧光屏 Fluorescent Screen
• ZnS (10–100 μ m) • Films • CCD
相对论修正 An additional correction to account for relativistic effects 透射出的电子束包含有电子强度、相位、以及周期性的信息，这些信息将被用于成像 The transmitted beam contains information about electron density, phase and periodicity. This beam is used to form an image
1940), Germany mathematician and Physicist physicist August Köhler (March 4, Moritz von Rohr (4 April resolving power of about a factor of two Ernst Abbe (* 23. † 14. Januar 1905), deutscher Astronom 1866 – March 12, Januar 1948), 1840; 1868 – 20 June 1940), Germany Physicist Germany Physicist
Single crystal LaB6 filament
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透射电子显微镜
原理 BACKGROUND
电子光学设备与成像设备 OPTICAL & DISPLAY
透镜 Lens • 电子束聚焦 Beam convergence • 三级透镜 Three stages of lensing
• 聚焦透镜 The condenser lenses • 物镜 The objective lenses • 投影透镜 The projector lenses
最初研究 INITIAL DEVELOPMENT
Riecke Ferdinand Braun Max Knoll Group Hans Busch Adolf Matthias & Max Knoll Julius Plücker 对物体细节的分辨率受到用于成像的光波波长的限制 使用磁场可以使阴极射线聚焦 August Köhler and Moritz Rohr 成功的产生了在阳极光圈上放置的网格的电子放大图像 —— 第一台电子显微镜 制镜者方程在适当的条件下可以用于电子射线 考虑了透镜设计和示波器的列排列，研制可以用于产生低放大倍数（接近 1:1）的电子光学原件 阴极射线示波器 磁场可使阴极射线弯曲 The ability to resolve detail in an object was limited approximately The cathode rays could be focused by Successfully generated magnified images of mesh grids placed over the anode aperture The lens maker's equation could be applicable to under appropriate assumptions Attempted to obtain the parameters that could beelectrons optimized to allow for construction of better 研制出可以将极限分辨率提升约一倍的紫外光显 by the wavelength light used in imaging Builtdeflection primitive of cathode ray oscilloscopes The "cathode rays" (electrons) of the magnetic fields, allowing for simple lens Arguably the first electron microscope CROs, as well as the development of electron optical components which could be used to was possible by the use of magnetic fields 微镜 (CROs) intended as a measurement device designs generate low magnification (nearly 1:1) images 光学显微镜分辨率仅在微米级 Developments into ultraviolet (UV) limits the resolution of an optical microscope to 1926 1858 1931 Ferdinand Braun 1891 1897 Julius Plücker1928 (16 July 1801 microscopes allowed for (4 April in 1868 – 20 June – 22 May 1868) German an increase a few hundred nanometers
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原理 BACKGROUND
电子源 SOURCE FORMATION
材料 Materials 两种物理现象 Two Physical Effects
•运动的电子在磁场中将会根据 • Tungsten or LaB6 右手定则受到洛伦兹 力的作用 •The interaction of electrons with a magnetic 高压电源 high voltage source (typically ~100–300 kV)
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The wave nature of electrons had not been fully realized until the publication of the 通过对棉纤维成像正式地 De Broglie hypothesis in 1927 1933 证明了 TEM的高分辨率