Electron optics of transmission electron microscope Lanting Zhang School of Materials Science and Engineering. SJTU lantingzh@sjtu.edu.cn Incld.specimen preparation
Electron optics of transmission electron microscope Lanting Zhang School of Materials Science and Engineering, SJTU lantingzh@sjtu.edu.cn Incld. specimen preparation 1
Why electron microscope? Robert Hooke(1635-1703) 1 mm 于17世纪晚期设计的显微 Human eyes 镜 10 Eukaryotic cells Eukaryotic cells 10 um Prokaryotic cells Prokaryotic cells 1 um Optical microscope nig's. Viruses 100nm% Viruses Ribosomes Pneumonia 10 nm Proteins 肺炎 Ribosomes 0 1 nm mF Heavy atoms 2 Heavy atoms 100pm 颗微镜底下成串的肺炎链球菊
Why electron microscope? 2 Human eyes Optical microscope Pneumonia 肺炎
From Hooke to Ruska Ernst Ruska 1 mm Nobel prize Human eyes in Physics 100um% 1986 Eukaryotic cells Eukaryotic cells 10 um Prokaryotic cells 5 Prokaryotic cells 1 um Optical microscope 100nm- Viruses Viruses Ribosomes 10 nm Proteins Ribosomes 0 1nm 1938 Vaccinia virus Heavy atoms 牛痘病毒 3 Heavy atoms 100pm
From Hooke to Ruska 3 Vaccinia virus 牛痘病毒 Ernst Ruska Nobel prize in Physics 1986 Human eyes Optical microscope
Why electron microscope? SEM micrographs ·Higher A ceramic specimen 1400X 1400X resolution in EM than you can in○M, 个 2800X TEM HRTEM micrograph micrograph LOM micrographs 四 四
Why electron microscope? • Higher resolution in EM than you can in OM. 4 A ceramic specimen
Why electron microscope? o Correlating morphological image to composition as well structure. Ni Cr 500nm B2 L1,PFZ M23C6 S50h Precipitation at grain boundary in an B=[112y。 5 alumina forming stainless steel
Why electron microscope? • Correlating morphological image to composition as well structure. 5 Ni Cr 500nm S50h B2 L12 M23C6 L12 PFZ Precipitation at grain boundary in an alumina forming stainless steel 𝑩 = [𝟏ഥ𝟏𝟐]γ
Frequency in Wavelength cycles per second in nm 106 m 400- 1020 Gamma rays Violet One angstrom 10- 450 Indigo One nanometer Blue X-rays 500- Ultraviolex Green 105 One micrometer Visible Light Yellow 104 Infrared Orange 人无令 One centimeter Red 100- Mobile Short radio waves phone One meter Short radio waves 109 Broadeast band One kilometer 105 Visible Light:X~6000 A 10 Long radio waves X-rays: λ0.5-2.5A Electrons: 元~0.05A
6 Mobile phone
LM Lamp TEM Electrons Similarity "lllumination" between OM and Glass lens Electromagnetic lens TEM Condenser lens Specimen Glass lens Electromagnetic lens Objective lens First image Glass lens Projector lens Electromagnetic lens Final image Ocular Fluorescent screen Eye 7
Similarity between OM and TEM 7
Resolution of TEM de Broglie relationship for the wavelength of any particle: h λ= mv h 1.5 >1=、 2meV 三 nm mv2 ev 二 2 8
Resolution of TEM 8 de Broglie relationship for the wavelength of any particle: 𝜆 = ℎ 𝑚𝑣 𝑒𝑉 = 𝑚𝑣 2 2 𝜆 = ℎ 2𝑚𝑒𝑉 = 1.5 𝑉 𝑛𝑚
Resolution of TEM de Broglie relationship for the wavelength of any particle: h λ= mv h 1.5 。λ= 二 nm mv2 √2meV 2 Acc.Voltage(kV) Wavelength (nm) 10 0.012247 20 0.00866 SEM 100 0.003873 200 0.002739 TEM 400 0.001936 9 1000 0.001225
Resolution of TEM 9 de Broglie relationship for the wavelength of any particle: 𝜆 = ℎ 𝑚𝑣 𝑒𝑉 = 𝑚𝑣 2 2 𝜆 = ℎ 2𝑚𝑒𝑉 = 1.5 𝑉 𝑛𝑚 Acc. Voltage (kV) Wavelength (nm) 10 0.012247 20 0.00866 100 0.003873 200 0.002739 400 0.001936 1000 0.001225 SEM TEM
h λ= eV mo:rest mass of 2moeV (1+2moCZ the electron TABLE 1.2 Electron Properties as a Function of Accelerating Voltage Accelerating Non-relativistic Relativistic Mass Velocity voltage(kV) wavelength(nm)） wavelength(nm) (x mo) (×108m/s) 100 0.00386 0.00370 1.196 1.644 120 0.00352 0.00335 1.235 1.759 200 0.00273 0.00251 1.391 2.086 300 0.00223 0.00197 1.587 2.330 400 0.00193 0.00164 1.783 2.484 1000 0.00122 0.00087 2.957 2.823 TABLE 1.1 Fundamental Constants and Definitions Charge (e) (-)1.602×10-19C 1eV 1.602×1019J Rest mass(mo) 9.109×10-31kg Rest energy(moc2) 511 keV Kinetic energy (charge x voltage) 1.602 x 10-19 Nm (for 1 volt potential)=J Planck's constant(h) 6.626×1034Nms 1A 1C/s Speed of light in vacuum(c) 2.998×10m/s 10
10 𝜆 = ℎ 2𝑚0𝑒𝑉(1 + 𝑒𝑉 2𝑚0𝐶 2 ) m0 : rest mass of the electron