Quantitative Measurement and Analysis of Annular Dark-Field STEM Image for Crystal Structure Analysis
Abstract: We have demonstrated quantitative annular dark-field (ADF) imaging for crystal structure analysis. Quantitative ADF contrast is given as a scattering intensity normalized by an incident probe current. We have developed a quantification procedure, in which the non-linear response of ADF detection system is corrected. Observed ADF quantitative contrast is in agreement with that of simulated images, and the quantitative ADF imaging allows us to directly count the number of graphene layers. We have also investigated how accurately atomic-resolution ADF images match between experiments and simulations. An appropriate effective source distribution function should be implemented in simulations, and we found the linear combination of Gaussian and Lorentzian functions well reproduces experimental profiles.
Key words: scanning transmission electron microscopy, annular dark-field, quantitative analysis, multislice simulation, graphene