Quantitative annular dark field scanning transmission electron microscopy for nanoparticle atom-counting: What are the limits?

Electron Microscopy and Analysis Group Conference 2015

De Backer, A.^1 ; De wael, A.^1 ; Gonnissen, J.^1 ; Martinez, G.T.^1 ; Béché, A.^1 ; MacArthur, K.E.^2 ; Jones, L.^2 ; Nellist, P.D.^2 ; Van Aert, S.^1

Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, Antwerp

B-2020, Belgium^1

Department of Materials, Uni Versity of Oxford, 16 Parks Road, Oxford

OX1 3PH, United Kingdom^2

关键词: Annular dark field scanning transmission electron microscopy;    Atomic resolution;    Detailed images;    Detection theory;    Image performance measures;    Industrial catalyst;    Probability of errors;    Statistical detection;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/644/1/012034/pdf
DOI  :  10.1088/1742-6596/644/1/012034

来源: IOP

【 摘 要 】

Quantitative atomic resolution annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique for nanoparticle atom-counting. However, a lot of nanoparticles provide a severe characterisation challenge because of their limited size and beam sensitivity. Therefore, quantitative ADF STEM may greatly benefit from statistical detection theory in order to optimise the instrumental microscope settings such that the incoming electron dose can be kept as low as possible whilst still retaining single-atom precision. The principles of detection theory are used to quantify the probability of error for atom-counting. This enables us to decide between different image performance measures and to optimise the experimental detector settings for atom-counting in ADF STEM in an objective manner. To demonstrate this, ADF STEM imaging of an industrial catalyst has been conducted using the near-optimal detector settings. For this experiment, we discussed the limits for atomcounting diagnosed by combining a thorough statistical method and detailed image simulations.