STEM-EDX tomography of bimetallic nanoparticles: A methodological investigation

Thomas J A Slater; Arne Janssen; Pedro H C Camargo; M Grace Burke; Nestor J Zaluzec; Sarah J Haigh

doi:10.1016/j.ultramic.2015.10.007

STEM-EDX tomography of bimetallic nanoparticles: A methodological investigation

Ultramicroscopy. 2016 Mar:162:61-73. doi: 10.1016/j.ultramic.2015.10.007. Epub 2015 Oct 22.

Authors

Thomas J A Slater¹, Arne Janssen¹, Pedro H C Camargo², M Grace Burke¹, Nestor J Zaluzec³, Sarah J Haigh⁴

Affiliations

¹ School of Materials, University of Manchester, Manchester M13 9PL, UK.
² Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
³ School of Materials, University of Manchester, Manchester M13 9PL, UK; Nanoscience and Technology Division, Argonne National Laboratory, Argonne, IL 60439, US.
⁴ School of Materials, University of Manchester, Manchester M13 9PL, UK. Electronic address: sarah.haigh@manchester.ac.uk.

PMID: 26780684
DOI: 10.1016/j.ultramic.2015.10.007

Abstract

This paper presents an investigation of the limitations and optimisation of energy dispersive X-ray (EDX) tomography within the scanning transmission electron microscope, focussing on application of the technique to characterising the 3D elemental distribution of bimetallic AgAu nanoparticles. The detector collection efficiency when using a standard tomography holder is characterised using a tomographic data set from a single nanoparticle and compared to a standard low background double tilt holder. Optical depth profiling is used to investigate the angles and origin of detector shadowing as a function of specimen field of view. A novel time-varied acquisition scheme is described to compensate for variations in the intensity of spectrum images at each sample tilt. Finally, the ability of EDX spectrum images to satisfy the projection requirement for nanoparticle samples is discussed, with consideration of the effect of absorption and shadowing variations.

Keywords: Bimetallic nanoparticles; Electron tomography; Energy dispersive X-ray spectroscopy.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.