Structural quantification of nanoparticles by HAADF STEM

Electron Microscopy and Analysis Group Conference 2013

Macarthur, K.E.^1 ; Jones, L.B.^1 ; Lozano-Perez, S.^1 ; Ozkaya, D.^2 ; Nellist, P.D.^1

University of Oxford, Department of Materials, Parks Road, OX1 3PH Oxford, United Kingdom^1

Johnson-Matthey Technical Centre, Blounts Court, Sonning Common, RG4 9NH Reading, United Kingdom^2

关键词: 3-dimensional structures;    Atomic columns;    Imaging parameters;    Incident beams;    Integrated intensities;    Reference data;    Scattering cross section;    Single images;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/522/1/012061/pdf
DOI  :  10.1088/1742-6596/522/1/012061

来源: IOP

【 摘 要 】

A new method of quantifying the HAADF STEM signal on absolute scale, building on the z-contrast nature of the technique, has been developed to address the problem of characterising nanoparticles to an atomic scale. Experimental images are scaled to a fraction of the incident beam intensity from a detector map. The integrated intensity of each individual atomic column is multiplied by the pixel area yielding a more imaging-parameter robust quantity, termed a scattering cross-section. Using this cross-section approach, and simulated reference data we show how it is possible to count the number of atoms in individual columns, in order to compare against theoretical 3-dimensional structures. All this is with the aim of trying to obtain as much information as possible from a single image of these beam sensitive samples.