Image contrast in TEM and its application Lanting Zhang School of Materials Science and Engineering SJTU lantingzh@sjtu.edu.cn 1
Image contrast in TEM and its application Lanting Zhang School of Materials Science and Engineering, SJTU lantingzh@sjtu.edu.cn 1
Lingual nerve recorded at 13500x.120kV 200 I um B110] 0,5pm Al cold-rolled LN 3nm 20 nm HHAADF MAG:5100000x HV:200.0KV
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Why there is no colour in the pictures? Understanding the B&W contrast in image. 3
Why there is no colour in the pictures? 3
Nature of image contrast Mass-thickness contrast Annular dark field (ADF-STEM) HAADF,if 0in>50 mrad Amplitude contrast Diffraction contrast Kinematic theory and expression Phase contrast (HREM) Thin specimen 10 nm 4
Nature of image contrast • Mass-thickness contrast • Annular dark field (ADF-STEM) – HAADF, if in > 50 mrad • Diffraction contrast – Kinematic theory and expression • Phase contrast (HREM) – Thin specimen < 10 nm 4 Amplitude contrast
Electron beam Objective lens Objective aperture (back focal plane) Fixed (diffraction pattern) SAD aperture Intermediate image 1 Strength→ Intermediate change lens Intermediate Intermediate diffraction image 2 pattern Projector lens Fixed strength www.globalsino.com/EM/ Diffraction Final pattern Screen image 5 (a) (b)
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