Mass thickness contrast in crystalline specimen For crystalline specimens,mass thickness contrast is obtained using Inelastic scattering High angle scattering in STEM (scanning TEM) ·lf0n>50mrad(~3), high angle annular dark field (HAADF)=Z-contrast image 11 Courtesy of Prof.Zuo at UIUC
Mass thickness contrast in crystalline specimen • For crystalline specimens, mass thickness contrast is obtained using – Inelastic scattering – High angle scattering in STEM (scanning TEM) • If in > 50 mrad (~3 o ), high angle annular dark field (HAADF) = Z-contrast image 11 Courtesy of Prof. Zuo at UIUC
Annular dark field (ADF-STEM) BF:bright field(明场) ADF:annular dark field(环形暗场) HAADF:high angle annular dark field(高角环形暗场) Incident convergent beam Specimen 02>10->50 mrads θ1>50 mrads off axis 03 <10 mrads B2/ HAADF 旧3 HAADF detector ADF ADF detector detector BF detector detector Schematic of the HADDF detector 12 from Fig.22.13 D.B.Williams and C.B.Carter,Transmission electron microscopy(2nd edition)
12 Annular dark field (ADF-STEM) Schematic of the HADDF detector from Fig. 22.13 D.B. Williams and C.B. Carter, Transmission electron microscopy (2nd edition) BF：bright field (明场) ADF：annular dark field (环形暗场) HAADF: high angle annular dark field (高角环形暗场)
ADF and HAADF images B//110] Cr Co 3 nm 100nm Nd2Fe4B,HAADF Single crystal Ni-base superalloy,yhy structure,ADF 13
ADF and HAADF images 13 Nd2Fe14B, HAADF Single crystal Ni-base superalloy, /’ structure, ADF
Diffraction contrast 色1 Al cold-rolled 0.5μm @LN14
Diffraction contrast Al cold-rolled @ LN 14